WSEAS CONFERENCES. WSEAS, Unifying the Science

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Volume 7, 2008
Print ISSN: 1109-2734
E-ISSN: 2224-266X








Issue 1, Volume 7, January 2008

Title of the Paper:  Performance Analysis of Direct Digital Synthesizer Architecture with Amplitude Sequencing


Authors: I. Jivet, B. Dragoi

Abstract: The paper presents an analysis of a novel DDS architecture based on direct amplitude algorithmic generation in its capacity to generate pure and high frequency signals. The algorithm implementation requires very few resources and is linear in digital precision length. In its simplest form includes one compare, two additions and several increments per iteration step. A solution to compensate the known major drawback of the algorithm, sample phase non uniformity in time, is presented. The versatility of direct digital synthesizers in frequency switching and phase modulation applications is shown to be preserved in the new architecture. The paper also presents an analysis of the potential of the proposed architecture performance as reflected in the low harmonic spectrum of the quadrature output signals. A FPGA implementation of the architecture was synthesized and simulated using a VHDL description to validate the solution as proposed. Synthesis reports are compared with other FPGA direct frequency synthesizer implementations as reported in recent literature.

Keywords: Amplitude centered DDS architecture, generated sine/cosine spectrum, FPGA implementation

Title of the Paper: FPGA Implementation of the Curve Generator Algorithm for H/W Acceleration Applications


Authors: I. Jivet, B. Dragoi

Abstract: The paper presents results of the implementation of a nonparametric curve generator algorithm in FPGA as a test of concept for H/W acceleration solutions. It is shown that coordinate sequences as a curve representation when generated by the algorithm form a nonuniform sampled cosine/sine sequences of values that can be used in signal generation applications. A known draw back of the algorithm is the phase non uniformity of the samples. The paper presents solutions to fix the non uniformity by sample time delay compensation. A time sequence compensated extension of the algorithm is presented for use in digital sine and cosine signal generation applications. The VHDL description of the extended algorithm as proposed was simulated and synthesized in a Xilinx family FPGA showing low gate count. Finally the paper explores a second extension of the algorithm for random value trigonometric function computation. The performance results are compared with recent known coordinate transform solutions implemented in FPGA using the CORDIC algorithm as reported in literature.

Keywords: H/W acceleration, Jordan's curve generator algorithm, FPGA implementation, CORDIC algorithm

Title of the Paper: Complex Chaotic Dynamics of the Double-Bell Attractor


Authors: M. S. Papadopoulou, I. M. Kyprianidis, I. N. Stouboulos

Abstract: In this paper a novel non-autonomous 4th order chaotic oscillator was investigated. This oscillator consists of a nonlinear resistance RN and a negative conductance Gn. We have studied the dynamics of the circuit for various values of the input sinusoidal signal vs(t) in the low frequency area, both theoretically and experimentally. We have demonstrated the birth and catastrophe of the Double-Bell strange attractor for different frequencies values, as the amplitude Vo of the input signal varies. This work is a precursor of future investigation of circuit’s application in secure communication systems.

Keywords: Driven circuit, Double-Bell attractor, Chaos, Spectrum analysis, Secure communication

Title of the Paper: Simulation Result about Harmonics Filtering using Measurement of Some Electrical Items in Electrical Installation on UHP EAF


Authors: Manuela Panoiu, Caius Panoiu, Mihaela Osaci, Ionel Muscalagiu

Abstract: This paper present the results obtained by simulation for the functioning regime improvement of an UHP Electric Arc Furnace. Because the nonlinearity of the electric arc the EAF functioning regime are perturbed from three causes: the current harmonics, the reactive power and the unbalanced load. In this paper there are study the possibilities of harmonics filtering and compensate the reactive power. The study was made using the results of some measurements made on an EAF and using an electric arc model for simulation. The simulations are performed in PSCAD EMTDC simulation program, a program dedicated to the power system.

Keywords: PSCAD-EMTDC simulation program, electric arc modeling, harmonics mitigation, filtering, reactive power compensation

Title of the Paper: About Stability of Mechatronic Systems Driven by Asynchronous Motors


Authors: Monica Adela Enache, Sorin Enache, Mircea Dobriceanu

Abstract: This paper presents two methods for stability analysis of mechatronic systems driven by asynchronous motors: an analytical method and a numerical one, original, conceived by authors. The presentation is accompanied by simulations and experimental results leading to credible conclusions.

Keywords: Stability, mechatronic system, asynchronous motor, parameters, simulation, Matlab, experiment.

Title of the Paper: A System for Video Conversion and Text Data Overlay


Authors: Rafic Bachnak, Ramya Chakinarapu, Mario Garcia, Dulal Kar

Abstract: This paper describes the design and development of a Video Conversion and Data Overlay (VCDO) prototype that takes in an analog National Television System Committee (NTSC) video signal generated by a video camera and data acquired by a microcontroller and display them in realtime on a digital panel. An 8051 microcontroller is used to acquire power dissipation by the display panel, room temperature, and camera zoom level. The paper describes the major hardware components and shows how they are interfaced into a functional prototype. Test data results are presented and discussed.

Keywords: Overlaying Text Over Video, Data Conversion, Real-Time Video

Issue 2, Volume 7, February 2008

Title of the Paper: Algebraic Derivation of the Oscillation Condition of High–Q Quartz Crystal Oscillators


Authors: Nicolas Ratier, Remi Brendel

Abstract: A symbolic–numeric method to simulate a high–Q quartz crystal oscillator is derived in this paper. The proposed method can take into account the isochronism defect of the resonator when high precision simulations are needed. The oscillator circuit is expressed under a canonical 5–terminal network which can be easily handled. The oscillator behavior is then described under the form of a nonlinear characteristic polynomial whose coefficients are functions of the circuit components and of the oscillation amplitude. The steady state oscillation amplitude and frequency are determined by solving the polynomial in the frequency domain. Moreover, if tolerance is assigned to each circuit component, efficient worst case analysis can be performed.

Keywords: Quartz Crystal Oscillator, Nonlinear, Simulation, Characteristic Polynomial, n–Terminal Network

Title of the Paper: Research and Implementation of A Novel DC High Voltage Power Supply


Authors: Zhao Yanlei

Abstract: The high voltage power supply is widely used in various fields. The paper presents detailedly the topology, the operation and the key techniques of a high precise direct current (DC) negative high voltage power supply. To enhance the power factor of input side and the voltage precision of output side, the power supply uses BOOST converter for power factor correction and voltage regulation. It converts DC to high frequency (HF) alternating current (AC) square wave with phase-shifted full bridge. The voltage of the AC square wave is boosted by HF transformer, then the HF high voltage AC square wave is double rectified to DC high voltage output. The HF high voltage transformer, which is designed and manufactured with special material—polytetrafluoro ethylene (F4) and special technique, solves several technical difficulties including influence of distributing parameters and insulation, and meets demands of high frequency, high voltage and high power. The supply’s output voltage is 25kV and its maximal output current is 100mA.The experimental result shows the power supply has high input power factor, stable output voltage and small ripple.

Keywords: Power supply high voltage Boost Transformer ZVS phase-shifted control

Title of the Paper: Ultrashort Pulse Measurement using High Sensitivity two Photon Absorption Waveguide Semiconductor


Authors: Mohammad Mehdi Karkhanehchi

Abstract: Two photon absorption in a reverse-biased pin AlGaAs optical waveguide is observed. This waveguide was used as a combined nonlinear mixer and detector of an autocorrelator for measuring the pulse width of 1.3μm wavelength optical pulses. The autocorrelation trace gives the FWHM of a 1.3μm Q-switched semiconductor laser to be approximately 13 ps.

Keywords: Two photon absorption, autocorrelator, semiconductor laser, Q-switching, optical waveguide

Title of the Paper: Mathematical Models of High-Speed Trains Movement


Authors: Cismaru Cristian Daniel, Nicola Doru Adrian, Manolea Gheorghe, Drighiciu Mircea Adrian, Bulucea Cornelia Aida

Abstract: In the paper it is presented the mathematical model of the useful movement of the high-speed trains. On the mathematical model basis it is built the structural diagram associated of the useful movement. The obtained structural scheme can be easily implemented in SIMULINK. An immediately example of the utilization of the useful movement model it constitutes the drawing of the movement diagrams, which it illustrates the dynamics aspect of the useful movement. Like application, by means of the SIMULINK model they are traced, on the basis of the traction and braking characteristics and of the imposed conditions of the route, the movement diagram of the high-speed train.

Keywords: modeling, simulation, electric vehicle, high-speed train, useful movement

Title of the Paper: Design and Implementation of Self-Calibration for Digital Predistortion of Power Amplifiers


Authors: Dua Idris, Yannick Le Moullec, Patrick Eggers

Abstract: The linearization of Power Amplifiers (PAs) on mobile handsets is a critical problem for stringent systems such as WiMAX. In this paper we present the results of our investigation on the feasibility of self-calibration from a theoretical point of view as well as on a FPGA-based hardware platform for the predistortion of PAs. We propose a system design in three phases i) self-calibration, ii) inverse function calculation and iii) predistortion. MATLAB simulation results show that the functionality of the self-calibration, inverse function calculation and predistortion can linearize the PA characteristics and that the FPGA implementation results of the self-calibration are promising, paving the way for an efficient self-calibrating digital predistorter.

Keywords: DPD, self-calibration, PA

Title of the Paper: Nonuniform Sampling Delta Modulation - Decoding Problems


Authors: Ryszard Golanski, Jacek Kolodziej

Abstract: The problems of reconstructing signals coded with use of adaptive sampling delta modulation have been shown in the paper. Synchronization procedure of the algorithm "with return to the basic sampling instant" has been analyzed. Investigations of the bit error robustness of the delta system with sampling adaptation have been presented. Special interest was aimed at the behaviour of Non-uniform Sampling Delta Modulation system with reference to the transmission errors. The phenomena of the parasitic oscillation and dynamic regulation of the dc level in the reconstructed signal, as a result of the channel errors, have been discussed. Parasitic oscillation parameters have been analyzed. It has been found that the algorithm "with return to the basic sampling instant" improves the bit error robustness of the adaptive sampling delta modulation.

Keywords: Adaptive delta modulation, Non-uniform sampling, Error compensation, Robustness, Parasitic oscillation.

Issue 3, Volume 7, March 2008

Title of the Paper: On Bifunctional Polymorphic Gates Controlled by a Special Signal


Authors: Richard Ruzicka

Abstract: Polymorphic digital circuits are circuits composed of polymorphic (multifunctional) as well as ordinary gates. In addition to its standard logic function (such as NAND), a polymorphic gate exhibits another logic function which is activated under a specific condition, for example, when Vdd, temperature, illumination or a special signal reaches a certain level. This paper describes existing polymorphic gates and their features, benefits and limits and discusses special class of polymorphic gates – bifunctional polymorphic gates controlled by a special signal. These gates seem to be most flexible polymorphic gates. In the paper a new two-input bifunctional gate for polymorphic circuits is proposed. The gate produces NAND or XOR function according to a special signal. The proposed gate is effective in terms of area overhead – it consists of 9 transistors only, while corresponding circuit employing conventional gates consists of more than 10 transistors.

Keywords: hardware engineering, digital circuits, CMOS logic gates, polymorphic electronics, VLSI, reconfigurable digital circuits

Title of the Paper: A Low Cost CPLD-Based Ultrasonic Flowmeter


Authors: Ioan Lie, Virgil Tiponut, Ivan Bogdanov, Sabin Ionel, Catalin Daniel Caleanu

Abstract: Based on the characteristics of ultrasonic non-contact measurement and the combination of temperature measurement with ultrasonic flow measurement, a flowmeter was designed. The structure of the ultrasonic flowmeter and the circuits of temperature and flow measurement were described. The design method of the meter with low power consumption was given by selecting MSP430 single chip microcomputer. In order to enhance flowmeter's precision and stability a Xilinx CoolRunner CPLD was applied in high precision timing. The result is a low cost portable solution working with a 3.3V supply and operating with ultrasonic transducers at 1MHz frequency.

Keywords: ultrasonic flowmeter, delay line, transit-time, CPLD, ultrasonic transducer

Title of the Paper: Dedicated hardware for Inheritance-Oriented Crossover Operation


Authors: Masaya Yoshikawa, Kentaro Otsuka, Hidekazu Terai

Abstract: Traveling salesman problem is basic combinatorial optimization problem of various practical applications in engineering. Genetic Algorithm (GA) is one of algorithms to solve the traveling salesman problem efficiently. GA is a powerful optimization algorithm, which is based on the mechanism of biological evolution. However, an essential difficulty exits in GA with regard to large amount of computation time, because GA is population-based search algorithm. Reducing the computational time is the most important priority, if GA is applied to practical problems. On the other hand, GA has three genetic operations, and the crossover operation is one of the most important genetic operations. In this paper, we propose novel hardware architecture for crossover operation in order to reduce computation time while keeping the search performance. The proposed architecture introduces a new hardware-oriented crossover algorithm considering character inheritance. Experiments prove that the proposed architecture achieves not only high speed processing but also reduction of the number of processing steps, while keeping the quality of solution.

Keywords: Hardware architecture, Crossover engine, Traveling Salesman Problem, Character inheritance, Genetic Algorithm, High speed processing

Title of the Paper: Dynamic Stability Analysis based on Energy-Passivity Considerations


Authors: Chieh-Tsung Chi

Abstract: This study aims at researching the relations between the stability characteristics of an ac contactor and the passivity conditions during power disturbances such as voltage sag. Based on the basic definitions of energy passivity, the stability performance of contactor can be determined by employing the flux linkage versus coil current curve of contactor. On the basis of the governing equations of ac contactor, a digital simulation model is first established. The correctness of the contactor model is verified by comparing the difference of the coil current and the armature displacement between model and contactor. The dynamic stability of contactor can be determined by the energy transferred direction in the electric part or the polarity of the time rate of the change of coil inductance. There are three types of voltage sag are respectively assumed to be the experimental case. Finally, we found that the results which were obtained from simulation tests agree well with those of the theoretical inferences. The identifying rules of the stability of contactor during voltage sag are presented here is valuable for the contactor designer to draft an effective compensation strategy in future so as to improve the momentary performance of contactor.

Keywords: Dynamic stability, contactor, passivity, energy, voltage sag, model

Title of the Paper: Current Or/And Voltage-Mode Quadrature Oscillators with Grounded Capacitors and Resistors using FDCCIIs


Authors: Jiun-Wei Horng, Chun-Li Hou, Chun-Ming Chang, Shih-Ting Cheng, Hsin-Yu Su

Abstract: Two quadrature oscillator circuits each using one fully differential second-generation current conveyor (FDCCII), two grounded capacitors and two grounded resistors are presented. The current-mode quadrature signals can be obtained from the first proposed circuit. The current-mode and voltage-mode quadrature signals can be simultaneously obtained from the second proposed circuit. In both proposed circuits, the current-mode quadrature signals have the advantage of high output impedance. The oscillation conditions and oscillation frequencies are orthogonal controllable. The use of only grounded capacitors and resistors makes the proposed circuits ideal for integrated circuit implementation. Simulation results are included.

Keywords: Quadrature oscillator, Current-mode, Voltage-mode, Current conveyor, FDCCII.

Title of the Paper: Efficient Implementation and Performance Evaluation of the Second Order Volterra Filter based on the MMD Approximation


Authors: Georgeta Budura, Corina Botoca

Abstract: Considered as a prototype of nonlinear system models the second order Volterra filter (FV2) is characterized by an increased complexity in comparison with a linear filter. This complexity is given by the large number of filter coefficients, as well as by the filter operations and it requires an increased computational power in technical applications. The filter based on the multi memory decomposition (MMD) structure represents a good approximation of the FV2 and significantly reduces the number of filter operations. In this paper we propose an efficient implementation of the MMD filter studied in a typical nonlinear identification problem. The simulations show the very good performance of our proposed MMD structure in comparison with the results obtained by using a second order LMS Volterra filter. We have evaluated the performance of our method based on the system response to different input signals.

Keywords: second order Volterra filter, multi memory decomposition, efficient implementation, performance evaluation

Title of the Paper: Reactive Power Requirements of Grid Connected Induction Generator in a Weak Grid


Authors: K. S. Sandhu, Shelly Vadhera

Abstract: Induction generators are gaining the popularity due to its simplicity and no synchronization problem. However the major drawback of this machine is its additional reactive burden on the system, where it is connected. In this paper an attempt is made to explore the performance of a grid connected induction generator (GCIG) due to weak grid conditions i.e. voltage and frequency fluctuations. Iterative model developed by the authors is used to predict the reactive burden of the generator due to voltage and frequency fluctuations. The comparison between experimental and simulated results proves the validity of technique proposed. Further proposed modeling is also used to include the effects of saturation.

Keywords: Grid connected induction generator, Iterative technique, Magnetizing reactance, Saturation, Weak grid

Issue 4, Volume 7, April 2008

Title of the Paper: Current-Starved Pseudo-Floating Gate Amplifier


Authors: Mehdi Azadmehr, Yngvar Berg

Abstract: In this paper we present Current-Starved Pseudo-Floating Gate (CSPFG) inverters with capacitive feedback. The analog CSPFG inverter suppresses low frequencies due to the active, local feedback. This inverter can be used in designing circuits and amplifiers where high frequency signal processing is the main goal. One good area of use is in filter design where a narrow band pass or reject filter is to be designed. Typical applications are detection of high frequency components in sensor signals, i.e. airbag sensors. AC simulation of the inverter is presented to show that the circuit is suited for high performance filter design. Linearity simulations of the analog CSPFG inverters shows the good transient properties suited for amplifier design.

Keywords: Analog, CMOS, Floating gate, Inverter, Amplifier, Filter.

Title of the Paper: Real-time Voltage Control to Improve Automation and Quality in Power Distribution


Authors: Francesco Muzi

Abstract: A new power digital voltage controller is described able to improve quality in power distribution using real-time compensation of both slow voltage changes and quick disturbances as sags and swells. Voltage control was achieved by means of a special transformer able to change the magnetic flux linked to the secondary winding; moreover, secondary voltage was monitored through a feedback control managed by a properly programmed micro-controller. The completely automated system includes a power section, namely a special transformer, a power electronic section consisting of an inverter driven by an actuator, and a digital section involving a micro-controller with implemented software. The capabilities of the proposed voltage conditioner were verified by laboratory experimental tests performed on a specifically manufactured prototype. Experimental results are reported and the behavior of the conditioner under different working conditions is discussed.

Keywords: Electrical distribution systems, Power quality, Power systems control and automation, Voltage conditioning.

Title of the Paper: Reliability Assessment and Improvement of Large Power Induction Motor Winding Insulation Protection System using Predictive Analysis


Authors: Mahfoud Chafai, Larbi Refoufi , Hamid Bentarzi

Abstract: The paper presents a reliability assessment of a widely used protection system of large power squirrel cage induction motors. In conjunction with published field induction motors Failure data this assessment effort is based on a integrated predictive analysis using three methods: (1) a Fault Tree Analysis (FTA) that allows to identify and then quantify the initiating failure cause weighting factors; (2) an Event Tree Analysis (ETA) that allows to predict the protection system probability outcomes following an external disturbance and (3) a Failure Mode Effect and Criticality Analysis (FMECA) that will help set the stage for developing a preventive maintenance program fit to keep up the induction motor protection system reliability at the required level with particular attention given to aggressive environmental factors such as found in cement plants.

Keywords: FTA, ETA, FMECA, Induction motors , Protection, Reliability , Failure Modes.

Title of the Paper: PWM Encoding Method for Wireless Communication in Sensor Networks


Authors: Ciprian Seiculescu, Ioan Lie, Aurel Gontean

Abstract: When designing low power sensor with radio capabilities the choice of the encoding for the radio signal can have great impact on performance and implementation requirements. The paper presents different encodings with their advantages and disadvantages, looking at both performance and implementation requirements. Finally the paper presents a proposed PWM encoding and the way that it was implemented and shows that the implementation advantages over other more traditional encoding outweigh the loss in performance. As well the paper presents different implementation methods for transmitters and receivers using the PWM encoding.

Keywords: PWM, amplitude modulation, Low power sensors networks, FPGA Prototyping, radio communication

Title of the Paper: Design and Implementation of DC Motor Speed Controller using Fuzzy-Adaptive Controllers


Authors: Hengameh Kojooyan Jafari

Abstract: As adaptive control systems have parametric construction and high accuracy against disturbances, and fuzzy control systems can compensate deficiency of dynamic parameters in time [1], in this paper fuzzy–adaptive controllers is used. Drive method is PWM and 8955 microcontroller is used for DC motor speed controlling. Simulation studies has been performed by MATLAB SIMULINK6.1 and SIDE51 (ver1.04R11) software by C language is used for program of controller and its compiler is used for making hex file to program 8955 microcontroller by EPROM PROGRAMMER (PGM89)[6,7] . The DC motor is VGFMED-BSMIB52 and driving IC is L298 IC.

Keywords: Fuzzy-adaptive control, Microcontroller, DC motor .

Title of the Paper: Optimization Frequency Design of Eddy Current Testing


Authors: Narong Mungkung, Komkrit Chomsuwan, Narong Pimpru, Toshifumi Yuji

Abstract: The purposes of this research were to construct the nondestructive metal testing instrument by using eddy current method and to find an optimal frequency for the metal testing instrument. The testing instrument consist of a sine wave oscillator circuit which can adjust the frequency between 20 – 90 kHz, and a 50 ohms sensor circuit. There are three kinds of testing instrument. The first was the nondestructive imperfection testing by using eddy current method. The sample irons are constructed with different imperfection on surface. The output signals of testing from the sensor circuit are compared. The second was the nondestructive categorization metal testing by using eddy current method. Many kinds of metals are taken to testing. The last one was the nondestructive testing for finding the thickness of films on iron by using eddy current method. In this testing the thickness of films varied between 100 – 700 microns. In all testing, differences of the signal testing were compared to analyze the optimal frequency for the testing instrument. The results of research showed that the nondestructive metal testing instrument by using eddy current method can be used to find a different imperfective iron, categorize the metal and find thickness of films. In addition, the range of an optimal frequency is 30 kHz to 70 kHz for testing instrument.

Keywords: Nondestructive , eddy current, thickness of films, optimal frequency

Title of the Paper: Behavioural Modelling of On-Chip Optical Interconnect with Potential Applications for Testing Linking-with-Light Circuits and Systems


Authors: HJ Kadim

Abstract: An integrated circuit (IC) or a system where light beams displace wires or metallic interconnects to pass signals between different subsystems requires new test techniques. Based on a knowledge of light properties and the transmitting medium, possible factors or parameters that may affect the propagation of light and the consequent changes in the expected output can be identified. Using these parameters as the ingredients, a mathematical model is constructed to study the effect of parameter fluctuations on the on-chip optical interconnect and hence providing information that will assist in identifying abnormal deviations in circuit’s behaviour.

Keywords: Optical interconnect, test, modelling, parameter fluctuations, SoC

Title of the Paper: Capacitive Sensing Device in a Postural Control System


Authors: Ivan Marinovic, Duje Coko, Igor Zanchi

Abstract: This paper presents a theremin used as a sensing device which provides a DC voltage output proportional to distance between the device and a human body in standing position. This device consists of a pair of Butler’s oscillators, a heterodyning mixer, a low-pass 4th order Butterworth filter and a frequency-to-voltage converter. Output signal may be sent to another device such as an actuator or a measurement module, depending on the application type. Three sets of measurements for various types of sensing electrodes have been taken, and a third degree polynomial function has been fitted using a least square method.

Keywords: Human posture identification, proximity sensing, theremin, Butler’s oscillator, posturography, least square method, curve fitting

Title of the Paper: On-Line Dynamic Cable Rating for Underground Cables based on DTS and FEM


Authors: Y. C. Liang, Y. M. Li

Abstract: The development of surface temperature on-line monitoring techniques for 110kV and above XLPE power cable gives a strong support to power cable load dynamic adjustment. However, the problem is how to determine the conductor temperature from the surface temperature. A technique based on distributed temperature sensing (DTS) and finite element method (FEM) is presented to estimate the soil thermal properties by matching the computed thermal fields to that obtained from measurement and predict the realtime current carrying capacity by iterative method in order to prevent overheat of insulation. Compare with the thermal circuit model, the method based on DTS and FEM is more accuracy.

Keywords: Online monitoring, Dynamic cable rating, Distributed temperature sensing, Finite element method, current carrying capacity, Underground cables

Title of the Paper: A Numerical Evaluation of Damages Caused by Asynchronous Motors to the Environment


Authors: Francesco Muzi, Luigi Passacantando

Abstract: In recent years a slow but progressive increase in the world’s temperatures has been consistently recorded. To oppose this global warming trend, two especially important actions are the monitoring and reduction of greenhouse emissions, in large quantity caused by global electric energy production. To this regard an algorithm is proposed to estimate the particles released into the atmosphere as a consequence of the electric energy produced for the operation of asynchronous motors, which in industrialized countries absorb as much as 60 % of the total electric energy generated. The described procedure can also help to evaluate the possibility to supply motors with electric energy produced from renewable sources instead of from thermal power plants supplying traditional public networks, which would of course reduce the environmental impact of motors to almost zero. Emissions linked to electric energy generation were evaluated on the basis of statistics collected from the main electric utilities. The proposed algorithm was validated by means of laboratory tests performed on a single asynchronous motor working under different operating conditions.

Keywords: Electric motor operation and consumption, Emissions and pollution, Environmental sustainability.

Title of the Paper: Device and Memory Array Models for Flash EEPROM Technology


Authors: Hassen Aziza, Bertrand Delsuc

Abstract: In this paper, three EEPROM memory cell models are presented. The first model is a compact model based on Mos Model 11 (MM11) and fully validated on silicon. From this first model we propose two alternative models (level 1 & level 2). These last models allow a reduction of simulation time and memory space overheads, with respect of accuracy, compared to the original compact model. The technique used to build the level 1 and level 2 models is based on the complexity reduction of the original EEPROM model. We also present simulation time results using the different models within memory arrays.

Keywords: EEPROM, Modeling, Memory arrays, Simulation time.

Title of the Paper: Use of RBF Neural Network in EMG Signal Noise Removal


Authors: V. R. Mankar, A. A. Ghatol

Abstract: The bioelectric potentials associated with muscle activity constitute the electromyogram (EMG). EMG signal is used in biomedical applications to detect abnormal muscle electrical activity that occur in many diseases and conditions like muscular dystrophy, inflammation of muscles, pinched nerves, peripheral nerve damages, amyotrophic lateral sclerosis, disc herniation, myasthenia gravis and others. In this paper, it is depicted that an RBF neural network as compared with other types of neural networks can be effectively used for EMG signal noise removal, which is a typical nonlinear multivariable regression problem. The performance parameters i.e. MSE and correlation coefficient are found to be in the expected range of values.

Keywords: EMG, RBF, MSE, MLP, PE, Correlation Coefficient, NN.

Title of the Paper: User Intention based Personalized Search : HPS (Hierarchical Phrase Search)


Authors: GunWoo Park, JinGi Chae, Dae Hee Lee, SangHoon Lee

Abstract: Personalized search has recently got significant attention in the web search. Accordingly, user’s intention of search is very important information to retrieval information in aspect of personalized Search. Although many personalized search and strategies have been proposed, the majority of web users are difficulty in retrieval information corresponding their search intention. In this paper, we present personalized search based on User Intention through the HPVM(Hierarchical Phrase Vector Model) to solve these problems using and machine learning methodology. Users can navigate through the prior user’s intention by their own needs. This is especially useful for various meaning and poor queries. By analyzing the results, we find out that there is an unique representation of user intention under different queries, contexts and users. Furthermore, we can find out that this knowledge is very important in improving personalized information retrieval performance by filtering the results, recommending a new query, and distinguishing user’s characteristics. With this approach, search engines can provide more predictive information for Web searchers. Based on this approach, we developed a personalized search engine, HPS (Hierarchical Phrase Search).

Keywords: Personalization, Information retrieval, Hierarchical phrase search, Support vector machine, Machine learning, Relevance feedback

Title of the Paper: An Efficient Error Resilience Scheme based on Wyner-Ziv Coding for Region-of-Interest Protection of Wavelet based Video Transmission


Authors: Zhuo Xue, K. K. Loo, J. Cosmas, P. Y. Yip

Abstract: In this paper, we propose a bandwidth efficient error resilience scheme for wavelet based video transmission over wireless channel by introducing an additional Wyner-Ziv (WZ) stream to protect region of interest (ROI) in a frame. In the proposed architecture, the main video stream is compressed by a generic wavelet domain coding structure and passed through the error prone channel without any protection. Meanwhile, the predefined ROI area related wavelet coefficients obtained after an integer wavelet transform will be specially protected by WZ codec in an additional channel during transmission. At the decoder side, the error-prone ROI related wavelet coefficients will be used as side information to help decoding the WZ stream. Different size of WZ bit streams can be applied in order to meet different bandwidth condition and different requirement of end users. The simulation results clearly revealed that the proposed scheme has distinct advantages in saving bandwidth comparing with fully applied FEC algorithm to whole video stream and in the meantime offer the robust transmission over error prone channel for certain video applications.

Keywords: Distributed Video Coding, Wyner-Ziv, Wavelet, ROI, Integer Wavelet Transform.

Title of the Paper: Benchmarking in Digital Circuit Design Automation


Authors: Lech Jozwiak, Dominik Gawlowski, Aleksander Slusarczyk

Abstract: This paper focuses on benchmarking, which is the main experimental approach to the design method and EDA-tool analysis, characterization and evaluation. We discuss the importance and difficulties of benchmarking, as well as the recent research effort related to it. To resolve several serious problems related to quality of benchmarking and use of practical industrial benchmarks, we proposed an adequate benchmarking methodology based on the statistical experimental design approach, and developed corresponding digital circuit benchmark generators. These benchmark generators enable research, evaluation and fine-tuning of circuit synthesis methods and EDA-tools largely independent of the actual industrial benchmarks, and much better than having only some industrial benchmarks. Using the results of extensive experiments that involved large sets of diverse benchmarks generated with our FSM benchmark generator, we discuss several crucial problems of benchmarking and demonstrate how to resolve them.

Keywords: Microelectronic Circuit Design, Digital Circuits, EDA-tools, Benchmarking, Statistical Experimental Design, Benchmark Set Quality

Issue 5, Volume 7, May 2008

Title of the Paper: A General Mathematical Model Based on Laplace and Modified Z-Transform for Time and Frequency Domain Investigation of Three-Phase Switched Circuits


Authors: Jiri Klima

Abstract: A general mathematical method for both the time-domain and frequency domain analysis of power converters with periodic switching cuircuits is proposed .The method is based on mixed using of the Laulace and modified Z-Transform in linear periodically time-varying system. The model was used for the analysis of three-phase voltage source inverters with Space Vector PWM feeding a three-phase static load, or an induction motor drive but it is applicable for all types of converters with an explicitly determined output voltage (converters with forced commutation) and periodical modulation..From the modulated waveforms we can easily obtained equations for the six step waveforms.The derived equations are validated using a 3 kW three-phase inverter.

Keywords: Mathematical model,Laplace transform,Modified Z-Transform

Title of the Paper: Pulse Density Recurrent Neural Network Systems with Learning Capability using FPGA


Authors: Yutaka Maeda, Yoshinori Fukuda, Takashi Matsuoka

Abstract: In this paper, we present FPGA recurrent neural network systems with learning capability using the simultaneous perturbation learning rule. In the neural network systems, outputs and internal values are represented by pulse train. That is, analog recurrent neural networks with pulse frequency representation are considered. The pulse density representation and the simultaneous perturbation enable the systems with learning capability to easily implement as a hardware system. As typical examples of the recurrent neural networks, Hopfield neural network and the bidirectional associative memory are considered. Details of the systems and the circuit design are described. Analog and digital examples for these Hopfield neural network and the bidirectional associative memory are also shown to confirm a viability of the system configuration and the learning capability.

Keywords: Hardware implementation, Pulse density, Hopfield neural network, Bidirectional associative memory, Learning, Simultaneous perturbation, FPGA

Title of the Paper: Lump Circuits Elements Values Extraction of Acoustic Transducers using Impedance Measurement Approach


Authors: Yeong-Chin Chen, Lon-Chen Hung, Shuh-Han Chao, Tseng-Hsu Chien

Abstract: Acoustic transducers are the popular elements for sonar array. The transducer of the simplify electrical equivalent circuit is discussed, and a impedance measurement system is developed to estimate the elements value of transducer’s lump circuit model at or near resonance. For practial application, a matching transformer is designed to make the transducer a high efficiency and high power transmitter. The experiment result approves the. Impedance Measurement Approach is the effective method for high power acoustic transducer development.

Keywords: Lump circuits, Elements values extraction, Acoustic transducers, Impedance measurement

Title of the Paper: Improvements in Power Quality and Efficiency with a new AC/DC High Current Converter


Authors: Francesco Muzi, Luigi Passacantando

Abstract: A very flexible AC/DC converter featuring high-output current, reduced voltage ripple and highly adjustable current control is described. The whole system consists of four stages and uses a proper switching technique in conjunction with a feedback control performed by means of a PID regulator. Moreover, the built prototype exhibits high efficiency and reduced harmonic pollution. In order to evaluate the harmonic distortion on the current drawn from the supply network, an FFT (Fast Fourier Transform) analysis is performed. Finally, experimental and computation results for output currents up to 400A, which confirm the correct behavior of the proposed converter, are presented and discussed.

Keywords: AC/DC converter, High direct-current, FFT, Electrical distribution systems, Power quality.

Title of the Paper: Design and Calculation Method for Dynamic Increasing Transmission Line Capacity


Authors: Lijia Ren, Xiuchen Jiang, Gehao Sheng, Wu Bo

Abstract: The Dynamic Line Rating (DLR) system is designed to improve the transmission capacity of overhead lines, which decreases or delays to re-build transmission lines. The system is composed of sampling terminals installed on dead-end configuration of a line and one control instrument equipped in dispatch center. The data between the sampling terminals and the control instrument is transmitted through GPRS/GSM. Through Ethernet, the control instrument exchanges data with SCADA interface in order to integrate DLR and SCADA system. A solar Photovoltaic (PV) power supply system based on Perturb & Observe MPPT techniques was designed and successfully applied to outdoor on-line monitoring DLR system. The paper analyzed mechanical actions for overhead line concerned wind speeds and wind direction in a deflection plane. The force balance for overhead line in wind was analyzed in detail, which deduces the mechanical model to calculate sags from the measured tension. Overhead line’s state equation was corrected used the relation of temperature and sags, and deduced the ultimately line’s temperature. Analyzed the advantages and drawbacks of some mathematical model used to calculate transmission capacity. In order that the DLR system received the optimum dynamic capacity curve, combined the WM and TS model. The result shows that the DLR system is effective in increasing line capacity without violating the legal ground clearance, monitoring the on-line parameters of transmission lines, and insuring the safe ground clearances of transmission line at all times.

Keywords: Dynamic Line Rating (DLR); Transmission line; Transmission capacity; Data acquisition terminal; Photovoltaic Power Supply, MPPT, Conductor sag; Conductor tension

Title of the Paper: Accident Analysis of a Surveillance Camera System through a Frequency-Based Processing


Authors: Jaejoon Kim, Dae Gyu Lee

Abstract: The surveillance camera systems are commonly used in detecting the traffic violation on the roads. A key requirement in most detection systems is the ability for rapid automated analysis to identify the accidents. This paper describes an accident analysis based on frequency information for detecting the accident, identifying the cause of the accident and storing the accident scene. When an accident happens, the surveillance system analyzes the accident sound and stores the accident scene in real-time. The proposed system utilizes the sound magnitude (dB) and frequency analysis (FFT) in order to increase the accuracy of accident assessments. In addition, this system accomplishes a continuous buffering without the presence of an accident. It stores the prior accident scene, accident scene and post accident scene. When this system is applied to the actual crossroads, it can detect the accident presence and save the inspection expense. Results of applying the proposed technique to data obtained from the detection of accidents are presented and compared.

Keywords: Traffic accident surveillance system, accident scene, sound analysis, frequency information, accident presence, accident inspection.

Title of the Paper: Embedded Real-Time Video Encryption Module on UAV Surveillance Systems


Authors: Ciprian Racuciu, Nicolae Jula, Constantin Balan, Cosmin Adomnicai

Abstract: A real-time video encryption module, developed to be used on an electrical accelerated mini-helicopter (UAV), is presented in this paper. The surveillance system is composed from six modules: image capture, encryption, two radio link modules, decryption and display module. The hart of the encryption system is the CV700C motherboard and it’s VIA C7 microprocessor with ultra low power consumption and efficient heat dissipation. For encryption, Rijndael algorithm was used.

Keywords: Encryption, Rijndael, DirectShow, Real-time, Wireless, Embedded

Title of the Paper: Identification of a Continuous Linear Time-Varying System using Haar Wavelet with Unit Energy


Authors: S. J. Park, K. J. Kim, S. W. Nam

Abstract: In this paper, identification of a continuous-time linear time-varying (LTV) system is proposed, where Haar wavelet with unit energy is employed. For that purpose, an algebraic equation is derived by expanding the input-output data and the time-varying impulse response using normalized Haar wavelets. Unknown wavelet coefficients for the a LTV system’s impulse response can be effectively estimated by solving the algebraic equation. Finally, the time-varying impulse response of a LTV system can be synthesized from the estimated wavelet coefficients.

Keywords: Linear time-varying system, impulse response, identification, Haar wavelet

Title of the Paper: A New Study in Maintenance for Transmission Lines


Authors: Lijia Ren, Xiuchen Jiang, Gehao Sheng, Wu Bo

Abstract: Because of increasingly common damage and thefts of the transmission towers, a new function is proposed to enhance the state maintenance of transmission lines. It relies on the monitoring of the high-voltage transmission towers to ensure the reliability and safety of the power grid operation. An approach which combines Independent Component Analysis (ICA) with neural network based on Particle Swarm Optimization (PSO) algorithm is presented. Its purpose is to extract the vibration source signals caused by the theft of the towers. Initially, the proposed algorithm separates the source vibration signals from the observed mixing signals based on the FastICA of negentropy and Exploratory Projection Pursuit (EPP). In order to distinguish the vibration pulse signal from other similar interference pulses, the algorithm of the feed forward neural network (FFNN) is used to identify the vibration pulses. It is trained online with particle swarm optimization (PSO), which incorporates the pulse extraction algorithm based on an adaptive threshold. Numerical results show that the algorithm is effective in extracting and identifying the vibration signals, and it also can suppress the interference signals.

Keywords: Transmission tower; ICA; Negentropy; Adaptive threshold; Particle swarm optimization (PSO); Neural network

Title of the Paper: Fuzzy Techniques in Analog Circuit Design


Authors: Gabriel Oltean

Abstract: The aim of his paper is to present some applications of fuzzy techniques in the optimization-based design of analog circuits. Our approach turns into profit the advantages offered by different fuzzy techniques. Fuzzy systems or fuzzy sets are involved in every algorithm phase. The optimization problem formulation is accomplished in a flexible manner using fuzzy sets to define fuzzy optimization objectives. Also, the initial guess of design parameters is based on matching degrees determined with fuzzy sets. The optimization engines use fuzzy systems to compute the coefficients to modify the design parameters in each iteration. In order to reduce the time spent for circuit performance evaluation, we use a fuzzy system to model each circuit performance. Two computer-aided design tools, at the cell level are developed in Matlab. A large collection of experimental results proves the validity of our approach. Different analog modules as simple transconductance operational amplifier, Miller operational transconductance amplifier, and common-emitter stage were designed for several sets of design requirements with very good results.

Keywords: Analog design, Multiobjective optimization, Fuzzy sets, Fuzzy systems, Unfulfillment degree.

Title of the Paper: A Genetic Algorithm based Approach for System-on-Chip Test Scheduling using Dual Speed TAM with Power Constraint


Authors: Chandan Giri, Dilip Kumar Reddy Tpparthi, Santanu Chattopadhyay

Abstract: Increasing complexity of System-on-Chip (SOC) has encouraged the engineers to design versatile automated test equipment (ATE) that can drive simultaneously different data channels at different data rates so that overall test cost can be reduced. Devices like Agilent 93000 series tester and Tiger system from Teradyne provide such flexibility to drive different channels at different data rates. Number of tester channels with higher data rate is limited due to different constraints like power rating of the SOCs, limitation of scan frequency, complexity of ATE etc. Hence proper utilization of the tester channels to reduce test time and thereby test cost is important. In this paper we provide a Genetic algorithm based approach for SOC-level TAM architecture optimization that minimizes testing time considering two different data rates for ATE channels. Our approach achieves better results than those reported in the literature. Experimental results show that the maximum improvement of 40.99% in testing time can be achieved.

Keywords: System-On-Chip test, Test scheduling, Test access mechanism, Dual speed, Power constraints, TAM, Power-constrained testing.

Title of the Paper: High-PSR-Bandwidth Capacitor-Free LDO Regulator with 50µA Minimized Load Current Requirement for Achieving High Efficiency at Light Loads


Authors: Huan-ChienYang, Ming-Hsin Huang, Ke-Horng Chen

Abstract: A capacitor-free LDO regulator with the minimized-Q (MQ) and adaptive zero compensation (AZC) techniques is proposed in this paper. With the MQ technique, light load efficiency is greatly improved since only 50iA minimized load current is required. Furthermore, due to noise cancellation from power supply, the LDO regulator with the MQ technique has higher PSR bandwidth with compatible compensation capacitors compared to the Q-reduction technique [1]. Besides, fast transient response time is also achieved because phase margin equals to 60 degree is always maintained by the MQ and AZC techniques. The capacitor-free LDO regulator with the MQ and AZC techniques was fabricated in TSMC 0.35im 2P4M CMOS process with small compensation capacitors 5pF and 1.5pF. Experimental results demonstrate that the minimum load can be reduced to about 50iA and transient response time can be reduced by the MQ and AZC techniques to be smaller than 4is. The measured load and line regulation are 20iV/mA and 3.3mV/V respectively.

Keywords: Capacitor-free LDO regulator, minimum load, frequency compensation, PSR bandwidth, fast transient response

Title of the Paper: Modeling and Design of Control System for Variable Speed Wind Turbine in All Operating Region


Authors: Wu Dingguo, Wang Zhixin

Abstract: In order to get the maximum power from the wind, the variable-speed wind turbine should run at different speed when wind speed changes. In this paper a control system is introduced to get this purpose base on establishing the three-mass model of the wind turbine. The control system consists of two parts: one is a speed controller for generator control; the other is a PI controller for pitch control. Simulation results by using actual detailed parameters for wind turbine show the effectiveness and robustness of this control system.

Keywords: three-mass model, feed-forward compensator, loop-shaping, speed controller, pitch controller, wind turbine, doubly-fed induction generator (DFIG)

Issue 6, Volume 7, June 2008

Title of the Paper: A Method for Content-Based 3D Model Retrieval by 2D Projection Views


Authors: Hang Xiao, Xiubin Zhang

Abstract: An effective approach for 3D model retrieval is to represent models by a set of projection views . In this paper, we propose a flexible framework for view-based 3D model retrieval. The framework provides users the ability to configure three components: the number of views, the type of views, and the 2D shape descriptors used to distinguish views. Because the three components are closely related to the performance of a view-based 3D model retrieval system and usually application-dependent, it is necessary to make them configurable. To achieve this goal, the framework employs a new view polyhedron positioning algorithm and provides an adaptable interface to its 3D shape feature extraction module. We build a demo 3D model retrieval system based on the framework. Experiment shows that the performance of the demo system is satisfactory.

Keywords: 3D model retrieval, information retrieval, 3D shape analysis, model feature extraction, viewbased models

Title of the Paper: Robust Control Applied to Improve the Performance of a Buck-Boost Converter


Authors: Wilmar Hernandez

Abstract: In this paper, H∞ loop-shaping control is applied to improve the performance of a buckboost dc-dc power converter based on pulse-width-modulation (PWM) techniques. Here, classical control techniques (i.e., proportional-integral-derivative (PID) control) and post-modern control techniques (i.e., H∞ control), are used to design the feedback loop of a buck-boost dc-dc power converter. The results of the experiment are satisfactory and show that robust controllers do not depend strongly on the operating point, and that H∞ loop-shaping control performs better than PID control.

Keywords: buck-boost converter, state-space averaging procedure, robust stability, PID control, H∞ loop-shaping control, disturbance rejection

Title of the Paper: Technological Process Optimisation and Process Characterisation in Relation to the Quality Assessment


Authors: Radovan Novotny

Abstract: In order to optimise and characterize technological processes for quality planning, evaluation and development purposes must be used proper methodology. Methodology for designed experiment and uncertainty can be one possible way to do this. Variation and effect of various technological factors in relation to the material structures stability, consistency and overall performance in the relation to the important aspects related to the observation and analysis of the influence more than one variable at a time on the response of interest.

Keywords: multi-vari analysis, variation, optimization, experiment, factor, response, design

Title of the Paper: Low Noise, Dual Gain Preamplifier with Built In Spectroscopic Pulser for Highly Segmented High-Purity Germanium Detectors


Authors: G. Pascovici, A. Pullia, F. Zocca, B. Bruyneel, D. Bazzacco

Abstract: We present a fast and very low noise hybrid front-end electronic device consisting of a complex charge sensitive preamplifier with a built in fast reset circuitry and a very accurate spectroscopy pulser. The front-end electronics was developed for the central electrode of 36-fold segmented, high purity germanium detectors in the frame of AGATA array of detectors. The intrinsic energy resolution in conjunction with a highly segmented detector is less then 900 eV for central electrode with a detector capacity of ~ 47 pF. The dynamic range of the central charge sensitive stage is as large as 100 dB, ranging from 0.1 fC to 10 pC, i.e. from ~2 keV to 180 MeV in terms of photon energy. To achieve such an unprecedented wide dynamic range, we split the whole spectroscopic range in four sub-ranges, namely 0-5 MeV, 0-20 MeV, 5-180 MeV and 20-180MeV, respectively. The first two ranges are measured with standard pulse-high spectroscopy techniques. Thereto, the analog electronics was designed with two conversions gains, 200 mV/MeV and 50mV/MeV, respectively to match the 1 V input dynamic range of the very fast pipe line ADC used by the digitizer units. To extend the pulse-height spectroscopy range well beyond the fast ADC analog input range, a new method was implemented and at a certain threshold we are switching from a standard pulse height analysis method to a time over threshold technique [TOT]. In order to achieve that, adjacently to the pole-zero cancellation circuit, a fast-reset circuit controlled by a fast comparator and an accurate zero crossing detector has been developed. Using this technique we can achieve an energy resolution of 0.04% at equivalent gamma energies of 180MeV. A programmable spectroscopic pulser has been designed and implemented in the central electrode (core) front-end electronic to achieve ‘self-calibration standards’ in both time and amplitude domain, which was needed to characterize such a complex, highly segmented high purity solid state detector.

Keywords: low noise, fast preamplifier, tracking gamma spectroscopy, extended ADC range

Title of the Paper: Hardware Accelerator for Evolutionary Robotics


Authors: Masaya Yoshikawa, Hidekazu Terai

Abstract: Evolution robotics is one of the autonomous learning and its approaches have been applied to various fields. In this paper, we discuss new evolutionary robotics technique. The proposed evolutionary robotics acquires their behavior using genetic-based machine learning. It adopts new if-then rules for learning algorithm. Moreover, it introduces novel hardware accelerator in order to reduce simulation time for calculation, since the genetics-based machine learning requires very long computational time. Experiments using quasi-ecosystem demonstrate not only the effectiveness of the proposed learning algorithm, but also that of the proposed hardware accelerator.

Keywords: Evolutionary robotics, Hardware accelerator, If-then rules, Genetic-based machine learning, Quasi-ecosystem

Title of the Paper: Aspects Regarding a New Method for the Optimal Control Law’s Synthesis of Aircrafts’ Move


Authors: Lungu Mihai, Lungu Romulus, Jula Nicolae, Cepisca Costin, Calbureanu Madalina

Abstract: The paper presents a new algorithm for optimal control law’s synthesis in rapport with state vector of the aircraft’s move. Starting from state equation of the movement, the system is brought to Jordan canonic form and Riccati algebraic matricidal equation (whose solution is the gain matrix of the control law) is brought to an equivalent form with transformation relation. The new gain matrix is partitioned conform to equations (35) ? (40). Using ALGLX algorithm, one studies elastic no deformed (no dimensional description) longitudinal and lateral move of an aircraft and dimensional elastic deformed move. One obtained Matlab/Simulink models and numerical programs and with them time characteristics expressing state variables’ dynamic are obtained.

Keywords: algorithm, optimal, control law, longitudinal and lateral move, synthesis

Title of the Paper: Optimal Control of Flying Objects’ Move After Estimated State Vector Using a Reduced Order Observer


Authors: Lungu Mihai, Lungu Romulus, Jula Nicolae, Calbureanu Madalina, Cepisca Costin

Abstract: In this paper one presents an algorithm for project of a reduced order observer (ALGLOOR) with applications to flying objects’ move. The command law is an optimal one in rapport with state vector of the observer. Numeric calculus examples are also presented: for longitudinal and lateral move and vertical move of a rocket in vertical plane in rapport with equal signal line; using Matlab/Simulink model of closed loop system one has made numeric calculus programs and with them one obtained different time characteristics, which expresses state variables’ dynamics of the flying objects dynamic models.

Keywords: algorithm, optimal, control law, rocket, state vector, reduced order observer, command

Title of the Paper: A Unified Treatment of Deterministic and Random Transients in Electrical Circuits


Authors: Sabin Ionel, Virgil Tiponuţ, Catalin Caleanu, Ioan Lie

Abstract: The continuity of capacitor voltages and inductor currents, well-known from the deterministic case, cannot be directly applied if the initial conditions are random. In this paper, new continuity relations for probability densities, mean values, correlation and covariance functions of the state variables are introduced. These continuity relations can be used for a global characterization of random transients. New formulas for initial condition and forced components of transient statistical moments are also presented. These formulas offer a direct approach for random transient analysis. Deterministic transients can be regarded as particular, degenerated, random transients. On this basis, one can develop a unified treatment of deterministic and random transients in electrical circuits. This unified framework is certainly an advantage, not only in teaching activities related to transient phenomena.

Keywords: Electrical circuit, Initial condition, Random transients, Statistical moments, Continuity relations

Title of the Paper: Optimum Sway Control for Overhead Traveling Cranes


Authors: Kamal A. Khandakji, K. P. Zdrozis

Abstract: Sway control for industrial applications and for cranes particularly is a historical problem that has accompanied the development in power semiconductors since the 1980’s. This article proposes a power semiconductor drive system, which can be used in the anti-sway control of overhead cranes driven three-phase induction motor. The developed system is based on the rotor current control. The proposed power semiconductor drive system is simulated using the developed comprehensive mathematical model. The performance of the proposed systems is analyzed and compared to voltage-controlled anti-sway system. A prototype of the proposed anti-sway control system is developed at the laboratory of electric drives and automation in ATEI – Greece, while the mechanism prototype was developed by the project sponsor - Arab Manufactures Company in Amman – Jordan.

Keywords: Anti-sway control, overhead traveling cranes, controlled current converter, three-phase induction motor.

Title of the Paper: Robustness of Systems with Various PI-like Fuzzy Controllers for Industrial Plants with Time Delay


Authors: Snejana Yordanova

Abstract: The robustness of the systems with fuzzy logic controllers (FLC) has lately focused the attention of researchers in relation with the expansion of their industrial application. The contemporary complex, nonlinear, time varying processes with time delay and various disturbances and the high demands for their control require to account for system stability and robustness in the FLC’s design. The simplicity of the design is of great importance in connection to its easy practical application. The aim of the present investigation is to develop a generalised procedure for the design of various PI-like FLCs with regard to system performance robustness and to compare the robustness of the control systems. The approach is developed for PI incremental and position FLCs based on the single input fuzzy controller (SI FC), Popov stability and Morari robustness and considers the control of industrial plants with time delay and model uncertainty. The main contributions are: 1) a generalised design procedure for FLCs accounting for system stability and robustness; 2) FLCs’ general tuning algorithm. The results are applied for the stabilisation of the air temperature in a furnace using MATLAB™. The performance of the designed FLC systems is assessed and compared to the performance of control systems with internam model controller via simulations.

Keywords: Frequency domain PI-like process FLC design, MATLAB, robust performance, temperature control, time delay, tuning algorithm

Title of the Paper: Noise-based Wavelet Denoising Technique for Partial Discharge Measurement


Authors: Zhou-Sheng Zhang, Deng-Ming Xiao

Abstract: For enhancement the insulation quality of medium voltage and high voltage power cables, on-site partial discharge (PD) diagnosis tests such as detection, location and identification are used to find defects or faults and assess ageing degree of the cable insulation. Typical test methods such as oscilating voltage waves (OVW), very low frequency (VLF) for medium cables and frequency-tuned resonance (FTR) for high voltage cables are adopted by far, especially for XLPE cable system. However, on-site interferences and noises make this PD detection very difficult. It requires a better method to extract PD pulses from severe noise circumstance. Wavelet transform technique used to suppress noises from PD signal (PDs) requires reasonable mother wavelet, amount of scales and thresholds to produce its best effect. This paper proposed a new wavelet-based denoising technique for on-site PD measurement of power cables. It aimed at applying discrete wavelet transform (DWT) with better denoising effect to on-site PD measurement. Firstly, it described and analyzed the testing methods for on-site PD measurement. Secondly, resonable amount of scales selection algorithm and threshold determine algorithm have been studied with this denoising technique. Finally, simulation studies associated with this method are presented. Moreover, previous wavelet denoising techniques are also studied here to compare to the new technique. Results indicate that this technique can not only attain better denoising effect but also improve the sensitivity of PD detection.

Keywords: Partial discharge, discrete wavelet transform, power cables, oscilating voltage wave, very low frequency, frequency-tuned resonance.

Title of the Paper: An Active Islanding Detection Method for Small-Scale Distributed Generators


Authors: Wen-Yeau Chang

Abstract: This paper proposes a new islanding detection method for use in a small-scale, grid-interconnected distributed generator system. The proposed islanding detection method is based on voltage fluctuation injection, which can be obtained through high-impedance load switching on the grid periodically. The correlation factor between the periodic switching signal and the perturbed voltage is then used as an islanding detection index in the proposed islanding detection method. Experimental results demonstrate the principles of the proposed technique and show the new proposed method is reliable, economical, and easy to implement.

Keywords: Islanding detection, Distributed generator, Voltage fluctuation injection, Correlation factor

Title of the Paper: An Efficient Scheduling Algorithm based on Multi-Frequency TAM for SOC Testing


Authors: Jiann-Chyi Rau, Po-Han Wu, Jia-Shing Ma

Abstract: In recent years the advance of CMOS technology has led to a great development, especially on the complexity of the system-on-chip (SOC). As the development of circuit with different technology, the embedded cores embedded into system-on-chips (SOCs) usually have multi-frequency to drive it. In this paper, we present a heuristic approach of TAM optimization according to the reality and reduce the test application time. The proposed method is applicable to the design model with hierarchy SOCs. We pay the price in hardware overhead in order to decrease test application time.

Keywords: SOC, Testing, TAM

Title of the Paper: Analysis of Signals Characterization of Circuits on the Traction Power Systems


Authors: Ying-Tung Hsiao, Kuang-Chieh Lin

Abstract: In this paper present the characteristics of the signals and ripple harmonics in the circuits of the traction power systems of the Taipei mass rapid transit system. This analysis provides a novel simulation method, using Matlab software program application to the signals and ripple and harmonics simulate. This investigation uses a reality circuits and systems to simulate the DC traction power system operation for the Taipei metro systems. The analyses discover that the ripple harmonics and operation waveform affect the circuits of the power system design, feature and regulation, and influence on the operation stability of the DC-link between the traction power and vehicle propulsion systems. The simulation data can observe the typical harmonic characteristics for the behavior of the DC traction power systems. This study reveals the running waveforms of the traction power rectifier and vehicle propulsion system operation that can be precise control and regulation. This analysis results of the characteristic of the operation waveform and ripple harmonics in the DC link systems can help engineers to identify system design and after maintenance regulation.

Keywords: harmonics, ripple, inverter, converter, DC link, traction power system.

Title of the Paper: SUT-CARG Car-Like Robots: Their Electronics and Control Architecture


Authors: Suchart Punpaisarn, Sarawut Sujitjorn

Abstract: This article presents the development of the SUT-CARG car-like robot system. CARG car-like robots consist of four mobile robot agents and are built as integrated systems with IR, sonar, ultrasonic, vision sensors and controller modules. Hardware details are given. The software interface module for commanding the robots is described. The article also presents the details of robot following control which utilizes geometrical control approach based on vision and image processing. Colour tracking and flocking of the robot agents are demonstrated (VDO available online

Keywords: Car-Like Robot, Visual Servo, Image Processing, Colour Tracking, Robot Following Control, Flocking.


Issue 7, Volume 7, July 2008

Title of the Paper: Neural Design Procedure for an ATTR System based on Video Imagery Usage


Authors: Constantin-Iulian Vizitiu, Petrica Ciotirnae

Abstract: It is well known that the design and effective development of ATTR systems incorporating in their architecture some characteristic elements belong to artificial intelligence represents and will represent a very important research direction in this area. Accordingly, in the current study a specific design algorithm for a full neural implementation of an ATTR system based on video imagery usage is described. Using an actual database, the theoretical and experimental results obtained confirm the great potential of the proposed design algorithm to be implemented into concrete ATTR application.

Keywords: ATTR system, pattern recognition, neural networks, video imagery

  Title of the Paper: An Adaptive Channel Parameter Estimation Using QQ-plot


Authors: Z. Djurovic, I. Kovacevic, B. Kovacevic

Abstract: New algorithm for estimation of parameters of communication channel in the circumstances of existence of intensive impulse noise within measurement sequence is proposed in this paper. Proceeding from the theory of robust estimation, a simple, adaptive, practically applicable algorithm is derived that in the circumstances of contaminated normal distribution of measurement noise demonstrates high level of efficiency. QQ-plot technique is used as a framework for estimation of contaminated measurements distribution providing the algorithm adaptation. Application of proposed algorithm is broad, both in the field of wireless communications, equalization of transmitting channels, suppressing of noise and in modeling communication and control systems.

Keywords: Channel identification, robustness, adaptation, QQ-plot

Title of the Paper: MIMO U-model Based Control: Real-Time Tracking Control and Feedback Analysis via Small Gain Theorem


Authors: Ali Syed Saad Azhar, Fouad M. Al-Sunni, Muhammad Shafiq, Jamil M. Bakhashwain

Abstract: In this paper, MIMO U-model based IMC is used for the tracking control of multivariable nonlinear systems. The algorithm is implemented in real-time on a 2DoF robot arm. The stability and convergence issues for the control-oriented U-model are also discussed. In order to guarantee stability and faster convergence speeds, bounds are suggested for the learning rate of adaptation algorithm that estimate the parameters of U-model. The adaptation algorithm is first associated with a feedback structure and then its stability is investigated using l2 stability and small gain theorem. The paper also discusses about the robustness of adaptation algorithm in the presence of noise and suggests optimal choices for faster convergence speeds.

Keywords: U-Model, LMS, Convergence Speed, Learning Rate, Small Gain Theorem

Title of the Paper: Utilization of Soft Computing to Improve Cooperative Management Efficiency


Authors: Seyed A. Shahrestani

Abstract: Provision of collaborative services requires cooperation among various entities of an organization. Furthermore, efficient management of any complex system, such as large enterprises or modern enterprise networks, depends on understanding the roles of its constituents and their interactions with one another. Interaction of humans is partially or fully dictated by their level of awareness of the capacity that others have in supporting them in fulfilling the tasks at hand. As such, awareness modelling and levels can play significant roles in improving the management efficiency. The awareness levels in human beings and managers have a fuzzy nature with linguistic variables extensively used in their characterizations and communications. Noting the underlying fuzziness, this paper explores how soft computing can be used to improve awareness modelling to achieve more effective cooperative management. This is further demonstrated through its application to an illustrative example that utilizes fuzzy proximity networks.

Keywords: Soft Computing, Fuzzy logic, Cooperative Management, Network Management, Awareness Modelling.

  Title of the Paper: New Ways for Terology through Predictive Maintenance in an Environmental Perspective


Authors: Torres Farinha, Inacio Fonseca, Antonio Simoes, Maciel Barbosa, Jose Viegas

Abstract: Terology is defined as the combined use of techniques of operational research, information systems and engineering, with the objective of accompanying the life cycle of facilities and equipments; it includes the definition of specifications referred to its purchase, installation and reception, as well as the management and control of its maintenance, modification and substitution and, still, its accompaniment in service. Under this perspective, maintenance is the core of terology and it correspond a subject that, instead of reducing importance of maintenance with the increasing of equipment reliability, it increases its role in the companies and obliges the increasing of the level of demand of professionals involved because of the new technical and environmental demands. This reveals the importance of this scientific area and the necessity to concentrate and to increase the research around it. The maintenance area is an example that offers challenges to both science and companies in order to optimize the performance of equipment and facilities. But, the scientific developments, namely in this area, must be more and more environmentally friendly or, in other words, must close the technology to nature, guarantying its life through an adequate maintenance management. It is because of this kind of challenge that the authors are developing new methodologies, almost antagonistic, because of the areas under development, namely diesel engines and wind generators, but as we will demonstrate, areas which are compatible and can contribute for a better environment. In the case of wind generators, the methodology aims to optimize the cycles of production and, consequently, reduce the other kinds of energy production. On the other hand, the methodologies for maintenance of diesel engines are based on environmental indicators that can predict the “health state” taking into account restrictions including health human factors among others. The new methodologies will later be incorporated through new predictive maintenance modules in an integrated maintenance management system called SMIT (Terology Integrated Modular System). The SMIT was developed as a traditional system, but it includes several innovations, like a fault diagnosis module, a non-periodic maintenance planning module and a generic on-condition maintenance module, among others. The new features will include, in the case of wind generators, on-line measures and the corresponding on-time treatment, using algorithms based on time-series forecasting and TCP/IP technology to transmit the signals. In the case of diesel engines, the algorithms are based on Markov chains and hidden Markov chains. It is based on these developments and the new researches mentioned so far, that this paper is built upon, and we believe that it will be a contribution to the maintenance management area.

Keywords: Terology; Maintenance management; Predictive maintenance; Diesel engines; Wind generators

Title of the Paper: Fast Stereo-based Visual Odometry for Rover Navigation


Authors: Aldo Cumani, Antonio Guiducci

Abstract: The object of visual odometry is the computation of the path of a rover from onboard passive vision data only. The approach presented here relies on the accumulation of ego-motion estimates obtained by stereo vision and bundle adjustment of tracked feature points. We also propose a new feature detector/descriptor, which is a simplified and faster form of other well known descriptors (SURF). For cyclic paths, a d/ej`a vu mechanism allows further control over the accumulated error. Tests on real-world data show that our descriptors are effective for accurate path estimation, while being fast enough for use in tasks such as autonomous planetary exploration.

Keywords: Robot localisation, Stereo vision, SLAM, Hessian feature detectors

Title of the Paper: Use of An Equivalent Thermal Network for the Analysis of a Coupled Thermo-Magnetic problem


Authors: Francesco Della Torre, Sonia Leva, Adriano Paolo Morando

Abstract: The coupled magneto-thermal problem is analyzed, with reference to a particular heating application, by means of an equivalent thermal network, that is based on a first-approximation interpretation of the field equations. The connections between the thermal characteristics and the magnetic ones are taking into account by considering the skin-effect and the dependence of electric conductibility on the temperature. Also the dependence of the produced heat – by Joule effect – on frequency is taken into account. A specific and straightforward applicative case is analyzed in order to underline the validity and the advantages of the proposed model. A single conductive loop is lighting by an impressed perpendicular magnetic field and both the forward and inverse problems are analyzed. An integration technique, based on Matlab-Simulink, is shown for the solution of the problem. Moreover, the dependence of the achieved results on the geometric characteristics of the analyzed system is studied.

Keywords: Electroheat applications, Coupled thermo-magnetic problem, Numerical method, Thermal network

Title of the Paper: Neuro - Adaptive Command Systems for Very Maneuverable Flying Objects


Authors: Lungu Mihai, Lungu Romulus, Jula Nicolae, Cepisca Costin

Abstract: One presents a dynamic model of the very maneuverable flying objects (A), which expresses the dependence between the vector formed by angles of A regarding aerodynamic trihedron and the vector of angular velocities of A or the vector of linear acceleration components in rapport with the trihedron related to A. Control structures (stabilization of movement) are also presented. These consist of loops after angles, angular velocities and linear accelerations and an adaptive control loop with neuronal network for dynamic inversion errors compensation of the non-linear function which describes unknown system of the dynamic model of A. Adaptive command is projected upon stability theory using Liapunov functions [1], [2], [3]. As calculus examples one presented two systems and stabilization models of the very maneuverable rocket’s longitudinal move [4]. Time evolution of the attack angle for the studied cases is also presented.

Keywords: dynamic model, adaptive command, neuronal network, rocket, maneuverable

  Title of the Paper: Systems for Move Stabilisation and for Aircrafts and Rockets Flight Optimization


Authors: Lungu Mihai, Lungu Romulus, Jula Nicolae, Cepisca Costin

Abstract: This paper deals with models of the rockets’ motion around mass centre, command laws of vertical and horizontal planes trajectory, stabilisation laws of the roll motion of the rockets and target control laws [1], [2]. One also studies the way to choose of the parameters of general command laws which assures state variables simultaneous cancellation. Some automatic control systems, using the previous laws, are also presented. Also, one presents some extremal systems for optimization of aircrafts and rockets’ flight using test signals for extreme’s search [3], [4].

Keywords: rocket, command law, target, control, extremal system, testing signal

Title of the Paper: Bifurcation and Chaotic Aspects in Peak Current Controlled Buck-Boost Converters


Authors: Dan Negoitescu, Dan Lascu, Viorel Popescu, Corina Ivan

Abstract: The paper investigates the bifurcation and chaotic behavior of a current-mode controlled Buck- Boost converter operating in continuous conduction mode (CCM). The analysis comprehends both open loop and proportional closed loop operation cases. Classical averaged dynamic models cannot predict the chaotic converters behavior which leads to typical phenomenology like period-doubling, quasiperiodic and chaotic operation. The most important dynamic behavior aspects are revealed by simulation, together with a rigorous mathematical description that exactly predicts the converters operation modes.

Keywords: Non-Linear dynamics, bifurcation, chaos, subharmonic oscillation, dc-dc converters, buck-boost converter, current-mode control, power electronics

Title of the Paper: Diagnosis and Repair Method of SoC Memory


Authors: Vladimir Hahanov, Anna Hahanova, Svetlana Chumachenko, Sergey Galagan

Abstract: An exact method of memory elements diagnosis and repair by spares that enables to cover a set of fault cells by minimally possible quantity of spares is represented. The method is oriented on implementation to the Infrastructure Intellectual Property for SoC functionality. It enables to raise yield essentially on the electronic technology market by means of faulty chip repair in the process of production and operation, as well as to increase the life cycle duration of memory matrixes by repair of them in real time.

Keywords: Diagnosis, System-on-Chip, Built-In Repair Analysis, Built-In Self Repair, Fault, Simulation.

Title of the Paper: Algebra-Logical Diagnosis Model for SoC F-IP


Authors: Vladimir Hahanov, Vladimir Obrizan, Eugenia Litvinova, Ka Lok Man

Abstract: Algebra-logical model, method and algorithm of fault embedded diagnosis in functional blocks of SoC are proposed. The reduced SoC Functional Intellectual Property Infrastructure that is characterized by minimal set of the embedded diagnosis processes in real time and enables to realize the services: testing of the nominal functions on basis of generable input patterns and analysis of output reactions; fault diagnosis with given resolution of fault location by means of utilization of the IEEE 1500 multiprobe; fault simulation to provide of realization of the first two procedures on basis of the fault detection table is presented.

Keywords: Diagnosis, System-on-Chip, Electronic System Level, Transaction Level Modelling, Infrastructure Intellectual Property, Functional Intellectual Property, Testbench, Fault

Title of the Paper: Selective Encryption Techniques of JPEG2000 Codestream for Medical Images Transmission


Authors: Zahia Brahimi, Hamid Bessalah, A. Tarabet, M. K. Kholladi

Abstract: In this paper, novel selective encryption image schemes based on JPEG2000 are proposed. The first one encrypts only the code-blocks corresponding to some sensitive precincts. In order to improve the security level we introduce the permutation of codeblocks contributing in the selected precincts. The idea of combining permutation and selective encryption is used in order to minimize the amount of processed data encryption while ensuring the best possible degradation through the permutation. Many of proposals format compliant encryption schemes for JPEG2000 that have been made encrypt packet body data, but leave header packet in plaintext. The second approach, combines code-blocks data encryption to a cyclic permutation of all packets headers in the bitstream. Actually, in the JPEG2000 codestream, packet header information is specific to the visual content, and it is can be used as a fingerprint of the codestream. Symmetric encryption AES with CFB mode is used to encrypt in the two schemes. The proposed schemes don’t introduce superfluous JPEG2000 markers in the protected codestream, i.e, its format is compliant to JPEG2000 codestream one. It keeps file format and compression ratio unchanged and doesn’t degrade the original error robustness. The proposed scheme works with any standard ciphers and introduces negligible computational cost.

Keywords: Communication system security, JPEG2000 Compression, Selective Encryption, permutation, medical images, Computer applications.

Title of the Paper: Optimal Voltage Assignment Approach for Low Power using ILP


Authors: Yu-Cheng Lin, Hsin-Hsiung Huang, Cheng-Chiang Lin, Tsai-Ming Hsieh

Abstract: In this paper, we proposed an optimal voltage assignment approach which determines the proper voltage for each gate in the gate level netlist using dual supply voltages. To the best of our knowledge, it is the first work to integrate the impact of the level shifters into the integer linear programming (ILP) formulations. The objective of the paper is to minimize the total power, including the gates and the level shifters, under the given delay constraints. For the gate level netlist, the voltage assignment approach, which determines the delay for gates and wires and the power for the gates and level shifters, is proposed. To reduce the runtime for the ILP constraints, we also propose the node-based concept to formulate the timing constraints. Finally, we optimally assign the voltages for all gates. The ILP formulations are solved by using the ILP solver (LINGO 10.0) and the experimental results with ISCAS circuits indicate the significant improvement on total power using the dual supply voltages.

Keywords: Dual Voltage, Low Power, Timing Constraint, Integer Linear Programming, Delay, Optimal

Title of the Paper: Different Methods for Direct Torque Control of Induction Motor Fed From Current Source Inverter


Authors: Aleksandar Nikolic, Borislav Jeftenic

Abstract: Two different methods for direct torque control (DTC) of induction motor fed from current source inverter (CSI) is analyzed in the paper. The first one is derived from well-known DTC strategy developed for voltage inverter drives. This type of control basically uses hysteresis type controllers for torque and flux. In CSI drive there is only one controller used for torque control loop. The problems that arises in such a drive is significant torque pulsations due to the nature of CSI and occasional speed drops because of variable switching frequency. The other DTC method, proposed in the paper, is based on constant switching frequency with modification of the inverter optimal switching table. Further improvements are reduced number of sensors since all measurements are performed in DC link only and in flux estimator. Both simulation and experimental results shows that this algorithm has better performance without problems that exist in the same drive with torque hysteresis comparator. Finally, proposed method is simpler for implementation in a real drive without rotational transformation and parameter dependences that exist in vector control of the same drive.

Keywords: DTC, hysteresis comparator, constant switching, CSI, induction motor

Title of the Paper: FPGA-based Real-Time Implementation of an Adaptive RCMAC Control System


Authors: Chih-Min Lin, Chao-Ming Chung, Chun-Fei Hsu

Abstract: T
he main advantage of the recurrent cerebellar model articulation controller (RCMAC) is its rapid learning rate compared to other neural networks. This paper proposes an adaptive RCMAC control system for a brushless DC (BLDC) motor. The proposed control scheme is composed of an RCMAC controller and a robust compensator. The RCMAC controller is used to mimic an ideal controller, and the robust controller is designed to compensate for the approximation error between the ideal controller and the RCMAC controller. The Lyapunov stability theory is utilized to derive the parameter tuning algorithm, so that the stability of the closed-loop system can be achieved. As compared with standard adaptive controller, the proposed control scheme does not require persistent excitation condition. Then, the developed adaptive RCMAC control system is implemented on a field programmable gate array (FPGA) chip for controlling a brushless DC motor. Experimental results reveal that the proposed adaptive RCMAC control system can achieve favorable tracking performance. Since the developed adaptive RCMAC control system uses a robust compensator to compensate for the approximation error, there is no chattering phenomenon in the control effort. Thus, the proposed control system is more suitable for real-time practical control applications.

Keywords: BLDC, FPGA implementation, RCMAC, adaptive control, Lyapunov function, neural control

Title of the Paper: A Second Order Autoregressive based Technique for Pipeline Leak Detection.


Authors: Marllene Daneti

Abstract: Efficient leak detection techniques need to be characterized both by rapidity and robustness. This paper studies a simple detection method based on the second order autoregressive (AR) parameters of the pipeline signals- a trade-off between the two required characteristics. The theoretical geometrical positions defined by the AR coefficients are developed for some particular cases of interest. The resulted model proves to be in concordance with the experimental data. The algorithm is next tested under non-stationary burst-type conditions induced both soft and hard, indicating a good stability in comparison with the basic most inexpensive computational detection method. The area under the Receiver Operating Characteristics (ROC) curves indicates also a better performance of the proposed detector.

Keywords: Leak detection, pipeline monitoring, AR models, ROC curves.

Title of the Paper: Design Optimization of Discrete-time Single-Loop Sigma-Delta ADCs via Nonideality and Power Analyses


Authors: Fu-Chuang Chen, Meng-Syue Li

Abstract: A conventional SD ADC design approach is a time consuming process and needs much trials and errors. An optimization algorithm for the discrete-time single-loop SD ADCs design is proposed. Circuit nonideality models are derived in output noise power forms through a systematic circuit imperfection study. A power model is also presented in order to estimate relative power consumption. These models reveal that design parameter variation can potentially affect several noises and errors in different ways, and may change system power consumption. This design complexity is qualitatively summarized into a table. Model completeness allows us to propose an optimization algorithm to search globally for a design parameter combination which meets SNR requirement while minimizing power consumption. Our optimization algorithm is tested against two published design results, and is verified by behavior simulations. Comparisons with behavioral-simulation-based optimization approaches are also made.

Keywords: Sigma delta modulator, noise model, power model, optimization.

Issue 8, Volume 7, August 2008

Title of the Paper: Distributed Simulation and Profiling of Multiprocessor Systems on a Chip


Authors: Zdenek Prikryl, Tomas Hruska, Karel Masarik

Abstract: Embedded systems – multiprocessor systems on a chip with application specific instruction-set processors (ASIPs) – become indivisible part of our everyday lives. They are everywhere. Therefore, powerful and flexible way of design and simulation of these systems is needed. The simulators of ASIPs are created using an architecture description language called ISAC. In this paper, the basic concept of simulation, the communication protocol among ASIPs and the three-state synchronization protocol that is used in the distributed multiprocessor simulation are described. Further, the basic concept of profiling and consequential evaluation of profiling information is described. One needs the results from the simulation itself and the results from the profiling to find bugs in the system and to optimize the system as a whole.

Keywords: Application specific instruction-set processor, multiprocessor system on a chip, simulation, simulator, synchronization protocol, communication protocol, profiling, ISAC.

Title of the Paper:  Impact of Voltage Source and Initial Conditions on the Initiation of Ferroresonance


Authors: Kruno Milicevic, Ivan Rutnik, Igor Lukacevic

Abstract: The impact of voltage source and initial conditions on the initiation of ferroresonance is investigated. The investigation is carried out by simulating the behaviour of the mathematical model of ferroresonant circuit realized in the laboratory. The initiation of ferroresonance is investigated by varying the values of phase shift and amplitude of voltage source in order to incite the ferroresonance. Thereby, the initial conditions are varied within a practically possible range of initial values of transformer voltage and transformer flux linkage.

Keywords: Ferroresonance, Iron-cored reactor, Bifurcation diagram, Chaos, Nonlinear circuits

Title of the Paper: An Enhanced Congestion-Driven Floorplanner


Authors: Yu-Cheng Lin, Shin-Jia Chen, Ping-Liang Chen, Hsin-Hsiung Huang

In this paper, a rectilinear-based congestion-driven floorplanning algorithm is presented to enhance the wire congestion and the CPU runtime. The proposed algorithm contains two stages, including the simulated-annealing (SA) based approach with the concept of ant algorithm (SANTA) and the nonlinear programming based method. The objective of the first stage and the second stage are to minimize the multiple objectives, such as the area, wire length and wire congestion, and to further improve the wire congestion of the local congested region without the area overhead, respectively. First, the effective concept of the ant algorithm is integrated into the multiple objectives floorplanner, which simultaneously minimizes area, wire congestion and the total wire length, to speedup the runtime. Besides, the nonlinear programming (NLP) based formulations are provided to perform the module reshaping, which maximizes the common length between two adjacent congested modules. For the floorplanner, the sequential-pair (SP) presentation is utilized to deal with the floorplan data at every iteration. For each iteration of the floorplanner, we first use SANTA to improve the neighbor searching and reduce the runtime. After performing the first state, we will obtain a floorplan with the objectives of the area, wire congestion and total length. For the intermediate floorplan, we select the two adjacent soft modules located at the most congested regions and divide the two soft modules into a set of connected sub-rectangles. Hence, we further reduce the congestion by enlarging the common boundary between the selected adjacent modules. Of course, the modular reshaping technique significantly increases the common length and the capacity of pins to reduce the wire congestion by utilizing the nonlinear programming based approach. To deserve to be mentioned that there is no area overhead after we perform the modular reshaping for the selected adjacent modules. Compared to the results of the traditional SA, SANTA achieves an average
improvement on the area, the total wire length and CPU runtime by 3% and 8.1% and 23.0%, respectively. To show the superior to our approach, 30 floorplan samples are randomly selected from Microelectronics Center of North Carolina (MCNC) benchmarks. The experimental result shows that the reshaping method improves the wire congestion and total wire length by 22% and 1.54%, respectively.

Keywords: Simulated annealing, Ant algorithm, SANTA, NLP, Module reshaping, Floorplan

Title of the Paper: Image Contrast Enhancement using Morphological
Decomposition by Reconstruction


Authors: Ioan Jivet, Alin Brindusescu, Ivan Bogdanov

The paper presents a novel algorithm for the computation of the image decomposition using a morphological filter with reconstruction The target applications are image contrast enhancement especially those with high dynamic content. Both bright and dark regions contrast enhancement were considered. A new hardware efficient implementation of decomposition is presented. Following decomposition in 5 levels of detail a local contrast enhancement is performed. The new reconstruction algorithm and its hardware implementation as proposed is shown to be independent on structural element size and that it results in a predictable time frame operation. A mixed schematic and VHDL/Verilog description of the decomposition filters was synthesized and results show far higher speed performance compared with solutions found in recent literature. The FPGA implementation had as main objective real time operation. The performance of the architecture was found to exceed real time conditions of operation and fit into medium size FPGA. A test sample image was used for contrast enhancement schemes validation. The white areas local contrast was
enhanced expanding the gray scale for the detail levels after a parabolic series. The scale warping in the white areas resulted in contrast enhancement while the dark areas did not.

Keywords: image filtering, multi-dimensional kernel, FPGA implementation

Title of the Paper: A Coin Detection System by Coupled Printed Spiral Inductors


Authors: Junichi Fukatani, Sho Yamaguchi, Masayuki Yamauchi, Kazuhisa Yoshimatsu, Hisashi Aomori, Mamoru Tanaka

Abstract: This paper describes a coin detection system using coupled Printed Spiral Inductors (PS-Inductors). In this research, the PS-Inductor is composed of copper foil spiral on the printed board. As an advantages, the PSInductor can be made easily and does not need the iron core. The experimental measurement and the theoretical calculation of the inductance of the PS-Inductor are derived. This enables the easily realizable coin detection system using PS-Inductor. In this system, a coin can be identified as changes of the mutual inductance of coupled PS-Inductors. The mutual inductance is investigated by inserting the coin between two PS-Inductors.

Keywords: Coin detection, Mutual inductance, Printed Spiral Inductor, Combination inductance, Self-inductance

Title of the Paper: Analysis of Some Solutions that Improve Performances of Plate-Type Electrostatic Precipitators


Authors: Gabriel Nicolae Popa, Ioan Sora, Victor Vaida, Iosif Popa, Sorin Deaconu

Abstract: The plate-type electrostatic precipitators are use in burning industry applications and can treat large gas flows. The paper presents the maximum ionization distance, analytic and graphic, near discharge wires depending on the voltage supply frequency and the discharge wires radius. A problem of this type of precipitator is difficulty to collection high resistivity fly ash. In the inlet section the fly ash resistivity is moderate and is necessary to charge dust particles as many is possible. It is useful to use traditional dc energization. For the middle section and especially for outlet section, where the fly ash resistivity is high, it is necessary another supply solution for section because the charging particle decrease when is use traditional dc energization. The paper presents analysis of different types supplies of ESP sections. The intermitent energization of sections can be a cheap solution to middle and outlet section (without change the power supply structure, it is necessary the change of the automatic voltage control unit). It is important to know the current-voltage characteristics to obtain the optimal control of the amplitude, the voltage shape, the input power and the collection efficiency. With comparative analyze of the measured and computed characteristics, with different mathematical model of current-voltage characteristics, it can be found which models estimate the current-voltage characteristics for plate-type electrostatic precipitators.

Keywords: plate-type electrostatic precipitators, dc energization, intermitent energization, current-voltage characteristics, mathematical models

Title of the Paper: VLSI Architecture Design Approaches for Real-Time Video Processing


Authors: A. Ahmad, K. K. Loo, J. Cosmas

Abstract: This paper discusses the programmable and dedicated approaches for real-time video processing applications. Various VLSI architecture including the design examples of both approaches are reviewed. Finally, discussions of several practical designs in real-time video processing applications are then considered in VLSI architectures to provide significant guidelines to VLSI designers for any further real-time video processing design works.

Keywords: Dedicated, programmable, Very Large Scale Integration (VLSI) architecture, video processing

Title of the Paper: Design and Synthesis of a Configurable Fractional Order Hold Device for Sampled-data Control Systems


Authors: Koldo Basterretxea, Rafael Barcena, Unai Ugalde

Zero-order hold devices (ZOH) are mainly used in digital control applications to obtain the output analog signals of digitally implemented controllers. However, it is proved that special hold devices such as the fractional order hold device (FROH) can improve, if properly tuned, the performance of hybrid control systems. Although the applicability of these devices has been theoretically studied in numerous works, there is no report of real experimentation with digital controllers that include special hold devices for the control signal interpolation. This lack of real application experiments is mainly due to the difficulties encountered in implementing such hold devices with the processing speed and configurability that real-time digital controllers require. This paper describes a totally configurable digital design of a FROH device, adequate for any digital control system platform. The implementation of an 8-bit resolution FROH prototype has been carried out and its performance tested on a field programmable gate array (FPGA).

Keywords: Hold device, FROH, configurable hardware, FPGA, digital controller, D/A conversion

Title of the Paper: A Multi-layer Obstacles-Avoiding Router Using X-Architecture


Authors: Yu-Cheng Lin, Hsi-An Chien, Chia-Cheng Shih, Hung-Ming Chen

Abstract: In recent years, scaling down device dimension or utilizing novel crystallization technologies provide the opportunity of applying much more devices to integrated circuit fabrication. Due to emerging DSM effects, the research about routing has drawn much attention in VLSI Physical Design. In this paper, we will focus on three issues. One, the traditional Manhattan routing has longer length and larger delay than X-Architecture routing. Second, in multilayer routing, the delay of one via is much larger than the delay of Manhattan routing. Third, since a routed segment and macro cell should be considered as obstacles, we must consider the rectangle and non-rectangle obstacles, and consider the number of vias as well. Our algorithm can handle both rectangle obstacles and non-rectangle obstacles, and we use fewer vias and X-Architecture router by region to construct the multilayer routing trees. The main purpose is to obtain an obstacles-avoiding routing tree of minimal wire length and minimal delay.

Keywords: X-Architecture, routing, multi-layer, physical design, VLSI, algorithm

Issue 9, Volume 7, September 2008

Title of the Paper: Analog Adaptive Filter LMS Algorithm using CMOS 0.5 μm Technology


Authors: Jose E. Perez-Carmona, Hector M. Perez-Meana, Juan C. Sanchez-Garcia

Abstract: In this paper an analog adaptive filter circuit is presented, their coefficients are adapted with analog LMS algorithm using CMOS HP 0.5um technology. The layout simulation result shows fast convergence speed and low power consumption. The performance in configuration as an identifier shows that this circuit can be used in portables VLSI communications systems.

Keywords: Adaptive filters, LMS identifier, Analog CMOS circuits, Analog building blocks, Analog processing.


Title of the Paper: The Sigma-Delta CNN with Second Order Noise Shaping Property


Authors: Masatake Hirano, Hisashi Aomori, Tsuyoshi Otake, Mamoru Tanaka

Abstract: In this paper, a novel spatial domain 2-D sigma-delta modulation using two-layered discrete-time cellular neural networks (DT-CNNs) with multi-stage noise shaping (MASH) property is proposed. Although the sigmadelta modulation is widely used for realizing of analog to digital converter (ADC), sigma-delta concepts are only for 1-D signals. Signal processing in the digital domain is extremely useful in 2-D signals such as image processing, medical imaging, ultrasound imaging and so on. In the proposed architecture, the A-template is used for a digital to analog converter (DAC), the C-template works as an integrator, and the nonlinear output function is used for the bilevel output. Besides, due to the CNN characteristic, each pixel of an image corresponds to the cell of CNN, and each cell is connected spatially by the A-template. Also, the multi stage noise shaping (MUSH) property, which is one of a very effective framework for a high order sigma-delta modulation, is exploited for realizing a second order sigma-delta modulator by cascade connected first-order CNN sigma-delta modulators.

Keywords: Celluler neural network, Sigma-delta modulation, Image reconstruction, Image halftoning, Secondorder noise shaping.

Title of the Paper: On-Condition Maintenance of Wind Generators - from Prediction Algorithms to Hardware for Data Acquisition and Transmission


Authors: Inacio Fonseca, Torres Farinha, Fernando Maciel Barbosa

Abstract: Maintenance management is a subject that, instead of reducing importance, with the increase of equipment reliability, it increases its role in the companies and obliges the increase of the level of demand of professionals involved because of the new technical and environmental demands. Sometimes, scientific developments anticipate the company’s needs while other times it is the company that challenges science. The maintenance area is an example that offers challenges to both science and companies in order to optimize the performance of equipment and facilities. This is also the case of wind generators, because their expansion, evolution, maintenance and reliability guarantee, needs to be adequately articulated in order to maximize production time and, obviously, to optimize maintenance interventions. It is because of this kind of challenge that the authors are developing new methodologies in the area of wind generators that aims to optimize the cycles of production and, consequently, reduce other kinds of energy production. The new features include on-line measures and the corresponding on-time treatment, using algorithms based on time-series forecasting and wireless technology to transmit the signals. The prediction models uses regression techniques based on SVR, ARMA and ARIMA models, modified according to this specific case. The weather conditions and the technical and construction characteristics of wind generators are only some variables that we have in account in the models that are under development. But, if these conditions are important, it is also very important to collect, read and treat data from sensors placed in wind generators that, because their geographic dispersion, and difficulty of transmission, must be solved adequately and conjugated with the above referred algorithms, in order to implement an adequate system. This is the ambit of the present article that reports a wide approach of a subject that usually is managed separately, this is, the hardware from one side and the prediction algorithms from other side. This is possible because the team has being researching and developing algorithms and an information system, since many years ago, around the terology subject that is a wider vision of maintenance. Then, the new methodologies, above mentioned, will be, later, incorporated through new predictive maintenance modules in an integrated maintenance management system called SMIT (Terology Integrated Modular System). The base of SMIT is accessed through a client-server system and a browser system that includes the main modules of a traditional system, as well as a fault diagnosis module, a non-periodic maintenance planning module and a generic oncondition maintenance module, among other innovations.

Keywords: Maintenance management; Predictive maintenance; Wind generators.

Title of the Paper: Automatic Design of Optimal Logic Circuits Based on Ternary Quantum-dot Cellular Automata


Authors: Miha Janez, Iztok Lebar Bajec, Primoz Pecar, Andrej Jazbec, Nikolaj Zimic, Miha Mraz

Abstract: This paper treats the problems involved in the design of logic circuits based on novel processing platform. It begins with description of the ternary quantum-dot cell, an extended classic binary cell. These cells are basic building blocks of quantum-dot cellular automata. They are used to construct simple structures with inputs and output which implement some ternary logic function. These structures are employed as building blocks of larger and more complex circuits. The computer-aided design tool that finds an optimal implementation of a circuit by bottom-up approach is described. The search of a solution is based on iterative deepening. Since searching over all possible solutions is too computationally complex, heuristics are used to reduce the computation time.

Keywords: Quantum-dot cellular automata, Ternary quantum-dot cell, Computer-aided design, Ternary logic, Logic circuits, Iterative deepening, Heuristics

Title of the Paper: THAWS: Automated Design and Deployment of  Heterogeneous Wireless Sensor Networks


Authors: Sean Harte, Emanuel M. Popovici, Brendan O'Flynn, Cian O'Mathuna

Abstract: This research focuses on the design and implementation of a tool to speed-up the development and deployment of heterogeneous wireless sensor networks. The THAWS (Tyndall Heterogeneous Automated Wireless Sensors) tool can be used to quickly create and configure application-specific sensor networks, based on a list of application requirements and constraints. THAWS presents the user with a choice of options, in order to gain this information on the functionality of the network. With this information, THAWS uses code generation techniques to create the necessary code from pre-written templates and well-tested, optimized software modules from a library, which includes an implementation of novel plug-and-play sensor interface. These library modules can also be modified at the code generation stage. The application code and necessary library modules are then automatically compiled to form binary instruction files for each node in the network. The binary instruction files then wirelessly propagate through the network, and reprogram the nodes. This completes the task of targeting the wireless network towards a specific sensing application. THAWS is an adaptable tool that works with both homogeneous and heterogeneous networks built from wireless sensor nodes that have been developed in the Tyndall National Institute. Its advantage over traditional methods of WSN development is simplification of development.

Keywords: Wireless sensor networks, Automated application development, Code generation

Title of the Paper: Analog Adaptive Filter LMS Algorithm using CMOS 0.5 μm Technology


Authors: Jose E. Perez-Carmona, Hector M. Perez-Meana, Juan C. Sanchez-Garcia

Abstract: In this paper an analog adaptive filter circuit is presented, their coefficients are adapted with analog LMS algorithm using CMOS HP 0.5um technology. The layout simulation result shows fast convergence speed and low power consumption. The performance in configuration as an identifier shows that this circuit can be used in portables VLSI communications systems.

Keywords: Adaptive filters, LMS identifier, Analog CMOS circuits, Analog building blocks, Analog processing .

Issue 10, Volume 7, October 2008

Title of the Paper: Stability of Driving Systems with Induction Motors. A New Method of Analysis.


Authors: Sorin Enache, Alexandru Bitoleanu, Monica Enache, Mircea Dobriceanu

Abstract: - This paper analyzes the stability of the driving systems with induction motors by two methods. The first one consists in using the geometrical locus of the roots and the second one is an original method developed by authors. The paper details the mathematical models which are used, the results obtained by computer simulation and the conclusions obtained by carrying out the analysis.

Key-Words: - Driving system, stability, static converter, induction motor, simulation.

Title of the Paper: A 2.4-GHz ISM Band Delta-Sigma Fractional-N Frequency Synthesizer with Automatic Calibration Technique


Authors: Shiwei Cheng, Ke Zhang, Shengguo Cao, Xiaofang Zhou, Dian Zhou

Abstract: - In the paper, a programmable phase-locked loop (PLL) based ISM band fractional-N frequency synthesizer, commonly used in wireless communication system, is presented. The third order error-feedback Delta-Sigma modulator and high linearity offset phase frequency detector (PFD)/ Charge Pump (CP) are adopted to reduce close-in phase noise due to DS quantization noise folding. Automatic calibration technique is also introduced to select the optimal frequency sub-band of voltage controlled oscillator (VCO) automatically through process, voltage and temperature (PVT) variation. The Synthesizer is designed in UMC .18um RF process and has a die size of 1.5mm*2.3mm. The measured phase noise is -112 dBc/Hz at 1 MHz offset.

Key-Words: - Fractional –N Frequency Synthesizer, Delta-Sigma Modulation, Quantization noise folding, Automatic Calibration Technique.

Title of the Paper: Current Decomposition Methods Based on p-q and CPC Theories for Active Filtering Reasons


Authors: Alexandru Bitoleanu, Mihaela Popescu, Mircea Dobriceanu, Felicia Nastasoiu

Abstract: - This paper presents a comparative analysis of three current decomposition methods in three-phase systems without neutral wire on the basis of some case studies. The analysis takes into consideration the Currents’ Physical Components (CPC) introduced by Professor Czarnecki in 1988 [1], the active and the reactive components of the p-q theory of the instantaneous power introduced by Professor Akagi and his coauthors in 1983 [2] and a modified variant of the Akagi’s components proposed by the authors for the operation under unbalanced or nonsinusoidal conditions [3]. We propose four components of the current space-vector in terms of DC and AC components of the instantaneous active and reactive powers. The term of supplementary useless current vector is also pointed out. The analysis shows that the current decomposition which respects the definition of the instantaneous apparent power vector is useful for compensation reasons only if the supply voltages are sinusoidal. A modified definition of the components of the current is proposed for the operation under no sinusoidal voltage conditions. This case studies based-analysis allows finding again some deficiencies that Professor Czarnecki has pointed out relating to Akagi’s current decomposition [4], [5]. It is shown that the proposed active and reactive current components are identical to those of Czarnecki’s CPC theory.

Key-Words: - Active current, Reactive current, Unless current, Unbalanced load, Nonsinusoidal conditions.

Title of the Paper: Design and Implementation of a Chassis Dynamometer for Testing Battery-Powered Motorcycles


Authors: Ding-Tsair Su, Ying-Shing Shiao, Jui-Liang Yang

Abstract: - The objective of this paper is to design and implement a chassis dynamometer for testing dynamic characteristics of a battery-powered motorcycle (BPM). By using a load simulation system, which is constituted with a DC motor and two rollers, a roller of the test platform is connected to a DC motor through a torque sensor, and a controller is designed to control the DC motor to simulate driving resistance produced when the BPM runs on various roads. The test platform can simulate each drag force when the BPM is in acceleration or in a constant-speed drive, and also can simulate kinetic energy gained by the BPM when braking, deceleration and running downhill. A computer not only controls the test platform but also collects signals from sensors on the test platform and the BPM, and can analyze related data such as driving resistance, driving range, speed, kinetic energy recycle and so on. The test platform has an integral steel structure and a stable center of gravity, and the height and length adjustment of the machine is convenient and as well the test is easy to perform, thus it can provide efficient tests on battery-powered motorcycles (BPMs) which are currently popularized by all circles with great efforts, so as to achieve the objective of performance measurement, performance analysis and data collection. From experiment results, the BPM performance test platform can simulate various road patterns and complete an automatic testing process.

Key-Words: - Chassis dynamometer, Battery-powered motorcycle, Test platform, Driving resistance, Drag force, Kinetic energy recycle, Road patterns.

Title of the Paper: Design of a Fast, High Power Magnetic Generator for the Stimulation of Living Tissues: A Biomedical Engineering Application of Electromagnetism and Power Electronics


Authors: R. Charlet De Sauvag, Ph. Dondon, C. Martin, J. Donkin , B. Veyret

Abstract: This paper relates to the design and realization of a high power (6000 A, 650 V) magnetic generator delivering ultra short (340 μs) high intensity (2 T) pulses. More than ten years of technical collaboration between two important graduate engineering schools of Bordeaux were necessary to carry out this project. This practical realization was supported perfectly by the power electronics, electromagnetism and microprocessor courses given at ENSCPB and ENSEIRB graduate engineering schools. In the first place, we explain the educational interests of this realization. Then, we give a detailed description of the system, including the tests which were used to check the specifications. Finally we conclude on possible uses of our equipment in biomedical research. As an illustration of bio medical applications, our apparatus was used for tests on living tissues (animal, bacteria, etc).

Key words: Magnetic stimulation, Living tissues, Biological tests, Power electronics, Electromagnetism.

Title of the Paper: A Comparative Study of Simple Online Learning Strategies for Streaming Data


Authors: M. Millan-Giraldo, J. S. Sanchez

Abstract: Since several years ago, the analysis of data streams has attracted considerably the attention in various research fields, such as databases systems and data mining. The continuous increase in volume of data and the high speed that they arrive to the systems challenge the computing systems to store, process and transmit. Furthermore, it has caused the development of new online learning strategies capable to predict the behavior of the streaming data. This paper compares three very simple learning methods applied to static data streams when we use the 1-Nearest Neighbor classifier, a linear discriminate, a quadratic classifier, a decision tree, and the Na¨ıve Bayes classifier. The three strategies have been taken from the literature. One of them includes a time-weighted strategy to remove obsolete objects from the reference set. The experiments were carried out on twelve real data sets. The aim of this experimental study is to establish the most suitable online learning model according to the performance of each classifier.

Key–Words: Data mining, Online learning, Static streaming data, Forgetting.

Title of the Paper: REI Equivalent Design for Electric Power Systems with Genetic Algorithms


Authors: Mihai Gavrilas, Ovidiu Ivanov, Gilda Gavrilas

Abstract: - Present day power systems are often large or very large systems, with a high degree of interconnectivity. Their analysis can be simplified using network equivalents, which decrease the size of the system by replacing a significant part of it with only a few nodes. The chosen equivalent is the REI equivalent. This paper describes a new approach to the problem of the REI equivalent design optimization, based on the sensitivity of the complex bus voltage from the internal unmodified section of the power system to a set of simulated representative contingencies. The optimal equivalents are determined using artificial intelligence techniques, namely genetic algorithms. The optimum design of the REI equivalent aimed to determine the number of REI buses to be used and the aggregation of external buses into the REI buses. The method was tested on a slightly modified version of the IEEE 57 bus test system. The obtained results prove the efficiency of the proposed method.

Key-Words: - Static network equivalents, REI equivalent, Load flow analysis, Contingency, Genetic algorithms, Sensitivity analysis.

Issue 11, Volume 7, November 2008

Title of the Paper: Device and Memory Array Models for Flash EEPROM Technology


Authors: Hassen Aziza, Bertrand Delsuc

Abstract: - In this paper, three EEPROM memory cell models are presented. The first model is a compact model based on Mos Model 11 (MM11) and fully validated on silicon. From this first model we propose two alternative models (level 1 & level 2). These last models allow a reduction of simulation time and memory space overheads, with respect of accuracy, compared to the original compact model. The technique used to build the level 1 and level 2 models is based on the complexity reduction of the original EEPROM model. We also present simulation time results using the different models within memory arrays.

Key-Words: - EEPROM, Modeling, Memory arrays, Simulation time.

Title of the Paper: Sensor Data Acquisition for Climate Change Modelling


Authors: Subana Shanmuganthan, Akbar Ghobakhlou, Philip Sallis

Abstract: - This paper describes recent advances in sensor technology and wireless radio frequency (telemetry architecture) with the capability for measuring changes in weather and atmospheric conditions that permit modellers to analyse the climate change, its variability and effects on viticulture across the world’s major wine producing regions. When combined with GPS (global positioning system) functionality enabling geo-referenced information to be gathered and analysed in real-time, new opportunities emerge for the development of wireless sensor networks (WSN) for decision making in precision agriculture (PA). The use of WSN technologies in precision viticulture (PV) to date is mostly confined to on-farm and narrow regions within a city or in the case of a larger region the data collection is limited to monitoring weather conditions alone. This paper reviews three application scenarios: a) within a vineyard b) regionally within the state of Washington in the USA and c) cities within the Asia Pacific Region. It then details the development of a system proposed for comparative analysis of viticulture management information from two countries, namely Chile and New Zealand that have the same latitude but are at different longitude points. The paper looks at a variety of remotely located real-time sensors (telemetry devices), associated hardware devices (server, workstation, architectures and topologies) and software suitable for data collection, logging, distribution and streaming. Data gathered by the sensors is relayed via a series of repeaters to a workstation, which logs the data and is connected directly to the Internet for transmission to a server acting as the final collection and data analysis point for a comparative information matching synthesis. The data collected is to be used for building models that could enhance our understanding about the effects of climate change on grapevine growth and wine quality within major wine regions in the two countries being studied in this initial research. Finally, the paper describes variable parameters considered for analysis in this research so far in relation to plant growth, weather, climate, atmospheric influences such as climate change, pollution and also wine quality determinants such as soil, terrain and grape variety.

Key-Words: - Telemetry devices, plant growth factors, weather data, GPS and precision viticulture.

Title of the Paper: Automatic Placement of Micropipeline Standard Cells


Authors: Alaaeldin Amin

Abstract: - A new algorithm for automated standard cell placement of asynchronous Micropipeline designs has been developed. The resulting placement solutions are targeted to meet all bundled-data timing constraints while providing efficient chip areas. The placement algorithm utilizes the simulated evolution iterative heuristic. The cost function is a weighted sum of an area factor and a timing factor. Results of five experimental circuits show that full routability with reasonably efficient areas are possible.

Key-Words: - Asynchronous systems; Micropipelnes; Automatic placement and routing; Stochastic Evolution.

Title of the Paper: Design and Implementation of a New Permanent Magnet AC Contactor with Colenoid Actuator


Authors: Chieh-Tsung Chi

Abstract: - This paper focuses on presenting a new permanent magnet with colenoid actuator for the purpose of reducing the energy dissipation during a complete operation. The methodology developed is a hardware based approach. It emphasizes on minimizing the cost of operation over a specified time period rather than a fixed operating point. The practical operating concerns of proposed ac permanent magnet (PM) contactor and the coordination with a new actuator are also addressed. The developed ac PM contactor has been implemented as a prototype grade product. Test results on the experimental prototype and computer simulation model show that the energy-saving performance of this newly developed ac PM contactor is effective and feasible.

Keywords: - AC PM contactor, permanent magnet, energy saving, simulation model, experimental prototype, actuator..

Title of the Paper: The Efficient TAM Design for Core-Based SOCs Testing


Authors: Jiann-Chyi Rau, Po-Han Wu, Chih-Lung Chien, Chien-Hsu Wu

Abstract: - This paper presents a framework and an efficient method to determine SOC test schedules. We increase the test TAM widths by the framework. Our method deals with the traditional scan chains and reconfigurable multiple scan chains. Experimental results for ITC’02 SOC TEST Benchmarks show that we obtain better test application time when compared to previously published algorithms. Test access mechanism (TAM) and test schedule for System-On-chip (SOC) are challenging problems. Test schedule must be effective to minimize testing time, under the constraint of test resources. This paper presents a core section method based on generalized 2-D rectangle packing. A core cuts into many pieces and utilizes the design of reconfigurable core wrappers, and is dynamic to change the width of the TAM executing the core test. Therefore, a core can utilize different TAM width to complete test.

Keywords: - SOC Testing, TAM, Testing Scheduling.

Issue 12, Volume 7, December 2008

Title of the Paper: Path Tracking Laws and Implementation of a Vision-Based Wheeled Mobile Robot


Authors: Ying-Shing Shiao, Jui-Liang Yang, Ding-Tsair Su

Abstract: This paper has studied techniques for building system configuration, control architecture and implementation of a vision-based wheeled mobile robot. The completed WMR has been built with the dead-reckoning method so as to determine the vehicle’s velocity and posture by the numerical differentiation/integration over short travelling. The developed PID controllers show good transient performances, that is, velocity of right and left wheels can track the commands quickly and correctly. Moreover, the path tracking control laws have been also executed in the DSP-based controller in the WMR. The image-recognized system can obtain motion information 15 [frames/sec] by using H-S model, which is one of the well -known color detection methods. The better performance a vision system has, the more successful the control laws design. The WMR obtains its posture from the deadreckoning device together with the vision system. Finally, we integrate these subsystems and complete the operators of the whole system. This complementing wheeled mobile robot system can be thought of as a platform for testing various tracking control laws and signal filtering method. To solve the problem of position/orientation tracking control of the WMR, two kinematical optimal nonlinear predictive control laws are developed to manipulate the vehicle to asymptotically follow the desired trajecto ries. A Kalman filtering scheme is used to reduce the bad effect of the imagine nose, thereby improving the accuracy of pose estimation. The experimental system is composed of a wireless RS232 modem, a DSP -based controller for the wheeled mobile robot and a vision system with a host computer. A computation -effective and highperformance DSP-based controller is constructed for executing the developed sophisticated path tracking laws. Simulation and experimental results are included to illustrate the feasibil ity and effectiveness of the proposed control laws.

Keywords: Predictive control, Mobile robot, Path tracking, Nonlinear characteristics, Kalman filtering

Title of the Paper: Evaluation Method of the Sensors Errors in an Inertial Navigation System


Authors: Teodor Lucian Grigorie, Nicolae Jula, Costin Cepisca, Ciprian Racuciu, Dan Raducanu

Abstract: The subject of this paper is a study of the influence of the inertial sensors errors on the position, speed and attitude of a bidimensional strap-down inertial navigation system in a horizontal plane. The MATLAB/SIMULINK models used for the acceleration and rotation sensors are based on the sensors data sheets and on the IEEE equivalent models for the inertial sensors. The models can be used in the numerical simulation of the strap-down inertial navigation system, close by real conditions from the point of view of the distortions suffered by the useful acceleration and rotation signals at the passing through any type of accelerometers or gyros desired to be implemented in the navigator. These models have the advantage to work independent from each of the sensors’ errors and thus to study their influence on the inertial navigator.

Keywords: Sensors Models, Positioning Errors, Inertial Navigator, Inertial Sensors, Strap-Down

Title of the Paper: Performance Analysis of High Speed Power Quality Disturbance Recognition Scheme for Static Transfer Switch Application


Authors: Ramesh Pachar, Harpal Tiwari, Ramesh C. Bansal

Abstract: The static Transfer Switch (STS) is a network reconfiguring device and is used for power quality improvement of sensitive loads. It selects, at high speeds, between two or more sources of power and provides the best available power to the sensitive load. This paper presents fundamentals of solid state STS with a detailed emphasis on power quality disturbance recognition scheme, as it is responsible for fast and accurate detection of disturbances, thereby ensuring healthy transfer of load to an alternate source. Extensive simulations are carried out for investigating the performance of rather commonly employed detection scheme. The behavior of detection scheme is analyzed against various types of disturbance scenarios including system transients.

Keywords: Power Quality, Static Transfer Switch, Detection Scheme, Transfer Time, Sensitive Loads, Custom Power Devices

Title of the Paper: Theoretical and Practical Aspects for Study and Optimization of the Aircrafts' Electro Energetic Systems


Authors: Nicolae Jula, Costin Cepisca, Lungu Mihai, Ciprian Racuciu, Tudor Ursu, Dan Raducanu

Abstract: The paper presents a concrete case of an actual aircraft electric power system analysis. Using the Boolean logical structures we define a conceptual fault tree. The fault tree will express all the combination of factors that can lead to system failure in the onboard electric system. The further on analysis rely on AND – OR logic elements, and the goal is to improve the fault-tolerance behavior of the system. The examples and numeric figures are for a c.c. electric power system of an operational aircraft.

Keywords: Reliability analysis, Boolean logic, aircraft, electric power, energetic system

Title of the Paper: Chaos-Low Periodic Orbits Transition in a Synchronous Switched Circuit


Authors: N. Jabli, H. Khammari, M. F. Mimouni

Abstract: In this paper we consider a modified model of an Alpazur oscillator with a periodically switching operation. Complex oscillatory phenomena are observed due to both switching operation and the appearance of an additional nonlinear component in circuit model. Indeed, subharmonic oscillations and chaotic behavior are illustrated. In addition, time series, phase trajectories and power spectrum was examined in the analysis of the system dynamics. The transition to chaotic states through doubling period bifurcation cascade and the direct transition from fundamental harmonic or odd subharmonic orbits and transition from a special bifurcation paths to chaotic states are discussed in the state space. The role of higher harmonic spectral lines in period-1 responses under parameter variation have seemingly similarities with the results obtained in previous works for non switched dynamical system. Chaotic states resulting from different transition modes are also presented in this paper. For the numerical simulations, techniques for deriving time and composite Poincare method are applied.

Keywords: Switching operation,Transition modes, higher harmonic predominance, doubling period cascade

Title of the Paper: Household Type Load's Effects on Photovoltaic Systems


Authors: Nazmi Ekren, Nevzat Onat, Safak Saglam

Abstract: The solar energy is one of the most important energy sources available because, besides the fact that it is not polluting the environment and it helps to the reduction of green house effect, it is free of charge and it can be easily converted to other forms of energy. Clean and renewable energy production is getting more attractive due to global warming, environmental factors and decrease in conventional energy sources. Photovoltaic cells will be a good alternative against the conventional energy sources in the near future, with their decreasing costs and increasing efficiencies. Photovoltaic cells (PV) are exposed to a lot of various loads depending on their increasing usage areas. Among the energy expenses for a building, the lighting system can contribute up to 50% of the total electrical consumption, and especially large quantities of energy are used in schools and office buildings. For that reason lighting devices are important energy consuming units in our daily life. In this study different load effects on PV cells are examined experimentally. D.C. and A.C. load behaviors are analyzed in switching and in steady state regime and their power-time curves are obtained for the demand of system power. Negative effects of the inverter circuit, which is used for feeding A.C. loads on the system, are expressed experimentally.

Keywords: Photovoltaic System, A.C. Loads, D.C. Loads, Power LED, Compact Fluorescent Lamp

Title of the Paper: The Application of Compound Neural Network in Condition Estimate of Power Transformer


Authors: Zhang Weizheng, Wang Zhenggang, Fu Yingshuan, Liu Fazhan, Yang Lanjun, Li Yanming

Abstract: The analyses of light gases in transformer oil provide the basis of a diagnostic evaluation of equipment health. Two new normalized methods which named characteristic normalization and mix normalization are presented in this paper. The Fisher rule to evaluate the results of the two pretreatment methods is also introduced. The evaluation of the results indicates that both of the two data pretreatment methods can achieve the purpose of big difference in the value of mean between classes and small difference in dispersion of a class. The DGA data of the failure transformers are treated by different normalization methods as the training samples, and then the samples are trained in the compound neural networks which use the CP algorithm. The diagnosis results of the test samples indicate that the new methods may help to improve the precision of network diagnosis.

Keywords: Transformer, analysis of reliability data, CP compound neural networks, condition estimate

Title of the Paper: NIRE: A New Approach in Obtaining Transfer Functions for a Linear Network


Authors: F. R. M. Rashidi, R. M. T. R. Ismail, R. Ishak

Abstract: Nowadays, there are lots of classic and alternative method that has been used to obtain and compute transfer function for a linear network. Although, problems still occur especially in the number of nodes, loops and simultaneous equations that need to be solved by this approaches. A proposed approach called NIRE (Network-Impedance Relationship Equation) will solve these problems by developing fixed equations for obtaining transfer function, rather than to extract its nodes, loops or simultaneous equations of its network. In this approach, the only required parameters are the network’s impedance connections which will be taken from two sources which are from the input terminal and output impedance. The approach has been developed in an algorithm using software called MATLAB. It can be adapted in a computer-based application and also can be introduced as an alternative method in obtaining transfer function for educational purpose.

Keywords: Transfer function, impedance, circuit, large-scale, linear, symbolic circuit analysis

Title of the Paper: Transition Faults Detection in Bit Parallel Multipliers over GF(2m)


Authors: Hafizur Rahaman, Jimson Mathew, Ashutosh K. Singh, Dhiraj K. Pradhan, Biplab K. Sikdar

Abstract: In this article, a C-testable design for detecting transition faults in the polynomial basis (PB) bit parallel (BP) multiplier circuits over GF(2m) is discussed. For 100 percent transition fault coverage, the proposed technique requires only 10 vectors, irrespective of multiplier size, at the cost of 6 percent extra hardware. The proposed constant test vectors which are sufficient to detect both the transition and stuck-at faults in the multiplier circuits can be derived directly without any requirement of an ATPG tool. As the GF(2m) multipliers have found critical applications in public key cryptography and need secure internal testing, a Built-in Self-Test (BIST) circuit may be used for generating test patterns internally. This will obviate the need of having three extra pins for the control inputs and also provides public-key security in cryptography. Area and delay of the testable circuit are analyzed using SynopsysO tools with 0.18m CMOS technology library from UMC.

Keywords: Transition fault, Galois field, multiplier, cryptography, error control code, VLSI testing

Title of the Paper: DSP Based On-line Partial Discharge Monitoring System for High Voltage Power Cable


Authors: Canxin Guo, Yong Qian, Chengjun Huang, Linpeng Yao, Xiuchen Jiang

Abstract: In high voltage power cable system, partial discharge (PD) is a common phenomenon which reflects the degradation of insulation. When partial discharge happens inside the cable, leakage current will flow through the grounded conductor. To couple the partial discharge current, one feasible and effective method is placing a clamp-on high frequency current transformer around the grounded strap. In order to precisely monitor the insulation degradation, a digital signal processor (DSP) based partial discharge on-line monitoring system is developed and presented in this paper. The system mainly consists of PD sensor, pre-amplifier, front-end sample device and remote server center. The front-end device is the kernel part of the system, as it performs PD signals sampling and some essential digital signal processing such as noise filtering, pulse extraction and parameters statistics. Then, the derived characteristic parameters are sent to the remote server center by ethernet communication for further analysis. The field test and data analysis show the presented system is effective and helpful for power cable condition diagnosis.

Keywords: High voltage, Power cable, Partial discharge, DSP, On-line monitoring, Signal Processing, Ethernet communication

Title of the Paper: Current Conveyor-Based Versatile Precision Rectifier


Authors: Montree Kumngern, Kobchai Dejhan

Abstract: A versatile precision rectifier based on a current conveyor and current mirrors is presented. The proposed circuit performs positive half-wave, negative half-wave, positive full-wave, and negative full-wave rectification into a single circuit. The current-mode technique has been employed to provide the high-precision capability of the circuit. The circuit configuration is very suitable for integrated circuit implementation both in bipolar and CMOS technologies and it exhibits a precise rectifier and good temperature stability. Simulation results using the PSPICE program based on 0.5?m CMOS parameter through MIETEC demonstrate the performance of the proposed rectifier. Experimental results are provided to confirm the theory.

Keywords: Precision rectifier, current conveyor, current-mode, half-wave, full-wave

Title of the Paper: Wu Elimination Method Applied in Static Analysis of the Power System


Authors: Qing Zhang, Chen Chen

Abstract: Wu Elimination Method is applied to obtain analytical solution of power flow equations without either extraneous roots or missing roots. The symbolic process of Wu Elimination is implemented by software MAPLE. A minor group of solutions is obtained under low load other than the major group of solutions. Based on computation, analytical , curves as well as the steady state operation area. The results are compared with the results of Homotopy Method. Discussion on unstable equilibrium points is presented which is potentially valuable for research on voltage stability and angle stability of complex power systems.

Keywords: Wu Elimination Method, Power system, curve, Voltage stability, Angle stability

Title of the Paper: A New Classification Pattern Recognition Methodology for Power System Typical Load Profiles


Authors: G. J. Tsekouras, F. D. Kanellos, V. T. Kontargyri, I. S. Karanasiou, A. D. Salis, N. E. Mastorakis

Abstract: In this paper a new pattern recognition methodology is described for the classification of the daily chronological load curves of power systems, in order to estimate their respective representative daily load profiles, which can be mainly used for load forecasting and feasibility studies of demand side management programs. It is based on pattern recognition methods, such as k-means, adaptive vector quantization, self-organized maps (SOM), fuzzy k-means and hierarchical clustering, which are theoretically described and properly adapted. The parameters of each clustering method are properly selected by an optimization process, which is separately applied for each one of six adequacy measures: the error function, the mean index adequacy, the clustering dispersion indicator, the similarity matrix indicator, the Davies-Bouldin indicator and the ratio of within cluster sum of squares to between cluster variation. This methodology is applied for the Greek power system, from which is proved that the separation between work days and non-work days for each season is not descriptive enough.

Keywords: Load profiles, clustering algorithms, adaptive vector quantization, fuzzy k-means, hierarchical clustering, k-means, self-organized maps, pattern recognition, adequacy measures

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