Wednesday, May 6, 2009

This paper describes the optimization, parallelization, and simulated performance of a software double-binary turbo decoder implementation suitable for software-defined radio (SDR) supporting the WiMAX standard. Turbo codes offer excellent bit-error rate (BER) performance, but present high computational requirements, hence a parallel approach is desirable when seeking to exploit the flexibility of SDR. The development of a flexible parallel maximum a postiori (MAP) decoding algorithm is detailed, with simulation speedup results demonstrating good parallel efficiency (above 80%). For the same number of threads, a linear-log-MAP decoder implementation using 4 iterations was shown to be have nearly twice the throughput with comparable BER performance of a max-log-MAP decoder implementation using 8 iterations. In addition to parallel execution, other performance enhancements in software and through customized instructions provide a combined per-thread improvement of up to 57%.

This paper presents a dynamic semantics for the parallel language HARPO/L, based on Reynolds's grainless approach. It shows that the approach scales to somewhat more sophisticated languages with few changes, while providing a solid semantics for the language, which will be used as a basis for compilation and optimization.

Super-resolution algorithms can be used to reconstruct a high-resolution high-quality image from a set of low-quality images. A novel hybrid demosaicing and color super-resolution approach proposed recently by Farsiu, Elad, and Milanfar relies on the minimization of a nonconvex multiterm objective function using a rudimentary fixed step-size steepest-descent approach. In this paper, we show that improved performance can be achieved by implementing this approach in terms of powerful quasi-Newton algorithms.

The advanced hardware based algorithms and architectures are very demanded for low-cost and high-performance motion estimation solutions. A hardware implementation for a novel H.264 motion estimator, with adaptive crossed quarter polar search patterns, is presented in this paper. Design trade-offs, including search patterns and memory accesses, have been made to target at very low implementation complexity. This hardware architecture is optimized for variable block sizes utilized in H.264 motion estimation. The architecture is mapped and verified with co-design techniques. The experimental results show that the proposed hardware motion estimator can sufficiently support the real-time 4CIF @ 30fps video encoding running at 50MHz, and yield an average PSNR of -0.05dB, +0.34dB and +0.11dB when compared to the full search, diamond search and adaptive rood pattern search algorithms, respectively.

Classical image-based visual servo methods regulate error in the image space and undergo difficulties when the initial and desired robot positions are distant. It is not trivial to introduce constraints in the realized trajectories and to ensure convergence due to the nonlinearity of the system. This paper proposes a trajectory planning scheme based on Probabilistic Roadmaps (PRM) in order to achieve more robust visual servoing through the introduction of desired constraints at the task planning level such as visibility and occlusion avoidance constraints that ensure the object remains in the camera field of view (FOV). Off-line path planning is performed on a 5DOF robot arm to confirm the validity of the approach.

This study proposes a Selective Compliant Assembly Robotic Arm (SCARA) with two revolute joints for poultry deboning. The joints of the arm are based on two high performance rotary type hydraulic actuators. These actuators are operated by servo valves, which control hydraulic fluid flow and direction. A PID based independent joint control system is considered for controlling the position of each joint. The system was modelled using the MATLAB - SIMULINK toolbox. The simulation results show that the arm was capable of covering a work envelope of 0.9 m x 0.9 m, reaching controlled velocities of up to 7.5 m/s with an average of 5.8 m/s. Obtaining such high speeds and torques would be a difficult task with electrical actuators of the capacity as the hydraulic counterparts considered here.

In this paper the comparative performances of the interior permanent magnet synchronous motor (IPMSM) drive system using proportional integral (PI) controller, proportional integral derivative (PID) controller, adaptive neural network (NN) controller, and wavelet based multiresolution proportional integral derivative (MRPID) controller are presented. In the proposed wavelet based MRPID controller, the discrete wavelet transform is used to decompose the error between actual and command speeds into different frequency components at various scales. The wavelet transformed coefficients of different scales are scaled by their respective gains, and then are added together to generate the control signal. The performances of the IPMSM drive system are investigated in simulation and experiments at different dynamic operating conditions. The vector control scheme of the conventional and proposed speed controllers based IPMSM drive system is successfully implemented in real-time using the digital signal processor board ds1102 on the laboratory 1-hp IPMSM. The simulation and laboratory test results confirm the superiority of the proposed wavelet based MRPID controller over the conventional speed controllers for wide spread applications in high performance industrial motor drive systems.

A model based efficiency optimization algorithm for speed control of interior permanent magnet synchronous motor (IPMSM) drive is proposed in this paper. In order to optimize the efficiency the loss minimization algorithm is developed based on motor model and operating conditions. The d-axis armature current is utilized to minimize the losses of the IPMSM in a closed loop vector control environment. The complete simulation model for the closed loop vector control of IPMSM drive incorporating the proposed loss minimization algorithm is developed using Matlab/Simulink software. The effectiveness of the proposed algorithm is tested in simulation at different dynamic operating conditions. It is found for the results that the efficiency of the proposed IPMSM drive is improved significantly as compared to the conventional id=0 control technique.

The purpose of a one-time password (OTP) is to make it more difficult to gain unauthorized access to restricted resources, like a computer account. Traditionally static passwords can more easily be accessed by an unauthorized intruder given enough attempts and time. By constantly altering the password, as is done with a one-time password, this risk can be greatly reduced. In this paper, we propose the new noisy password technique. The proposed system attempts to alleviate the problem of shoulder surfing or eves dropping by making the replay of a password useless. Every time a user is authenticated by totally different password. The noisy password constitute of several parts, the actual password and additional noisy parts that are well studied to generate different passwords almost every time a user wants to authenticate himself. The noisy parts are proven to be robust against any hacking attacks. Experimental results give good indication of the ease of utilization of the new system with low error rates that can be enhanced by time.

The existing restoration schemes require detailed link-state information to be advertised between the nodes in the network. This makes them less attractive to networks with multiple autonomous domains where network status information needs to be abstracted within each domain for efficiency and scalability reasons. In this paper, we present a distributed end-to-end shared restoration scheme, referred to as Virtual Node-based Shared Restoration (VNSR), which provides routing and shared restoration across multiple domains with limited information exchange among the domains. With this scheme, every domain is modeled as a single virtual node with a certain internal capacity that can be advertised to other domains. This minimum advertised information is used to compute a pair of link-disjointed primary and backup paths between any given source and destination nodes across the domains. The performance of the proposed scheme is evaluated and compared with another published scheme referred to as Virtual Path-based Shared Restoration (VPSR), which modeled every domain as a set of virtual paths. We will show that the VNSR scheme is more scalable and efficient in terms of the routing overhead, while still yielding the same capacity performance, compared with the VPSR scheme.

Cooperative diversity has been adopted to form virtual antenna arrays in order to obtain spatial diversity gains. Various partner selection methods in cooperative diversity systems were proposed and analyzed. However, these methods are not effective for users with high speed, such as users in cars on high way. A novel partner selection strategy is presented in this paper by dividing users into three groups according to their moving speeds and directions if there are any high speed users in a certain cell. The partners for cooperation are selected from the same group with the source user. Simulation results show that the selection strategy can increase duration of cooperation, as well as decrease the partner handoff times and probability of unsuccessful partner selection.

This paper introduces a new multiple-access technology named frequency band width division multiple-access (FBW-DMA). The proposed method processes signal in fractional Fourier transform (FrFT) domain to avoid some crucial problems in CDMA, such as high requirement of synchronization and suffering from single-frequency interference generated by other systems. By using chirp signals with different frequency band widths as carriers at the transmitter, transform the received signal into corresponding FrFT domain, then narrow band matching coherent demodulation is used. Simulation results indicate that the proposed frequency band width division multiple-access achieves better bit error rate (BER) performances compared with CDMA when serious single-frequency interferences exist, and the BER is lower one or two orders of magnitude.

Over the last two decades, extensive studies and research have opened a new era for Fiber Bragg Grating (FBG) based sensing technologies. One of the new applications is the FBG based accelerometers. In various field applications, FBG based accelerometers are replacing conventional electronic sensors, due to their long term stability, high accuracy and low power consumption. In this paper, theoretical analysis on FBG is introduced followed by the sensing principles. In-depth studies are made on three existing FBG based accelerometers for their unique transducer designs and signal interrogation techniques, and most importantly their possible use for seismic measurements.

A device for detecting advanced glycation end products (AGE) fluorescence spectrum of skin has been designed. Some of the AGE has special fluorescence. When the tissue of skin is illuminated with excitation light, fluorescence emitted by tissue is detected. The intensity of detected fluorescence is related with the concentration of tissue AGE, which can determine a tissue state of individual. The device can scan excitation light, and also can scan fluorescence emitted by tissue. Because the detection is performed noninvasively, the device could be adapted for using conveniently. We make use of the system to detect the excitation spectrum. At the same time, the emission spectrum is also be detected on the skin of no diabetic individual and diabetes respectively, the result of the experiment indicates that there are difference distinctly about 450nm between them. The patient can benefit from it to forecast and diagnose the state of illness such as diabetes, decrepitude, and oxidative stress etc. conveniently.

The need to train satellite ground station operators is of critical importance for the success of a space mission. An operator is responsible for monitoring the health of a spacecraft and recording of payload data. This paper proposes an architecture that reuses existing ground stations for training purposes in the form of emulation. Telemetry is simulated and transmitted to a ground station from a remote location, thus allowing the use of all the available physical equipment. In addition, means are provided for the simulator to inject noise and incorrect telemetry that test the operator's understanding not only of a satellite mission, but also their ability to react to anomalies that may occur. The paper also suggests incremental modes of training that guide an operator through different scenarios leading to communicating with an amateur satellite.

This paper outlines the design and implementation of Phase Two of the Command and Data Handling System for the WinCube project. WinCube is a multi-year, multi-disciplinary project conducted at the University of Manitoba in which students participate in the design of a CubeSat. The purpose of the WinCube project is to provide an opportunity for engineering students to design and develop a space ready satellite. The project also acts as a vessel for a high school science experiment, which will run an experiment while in space, and relay results down to a base station. The Command and Data Handling system must manage the operations and internal communications of the various systems inside the satellite. The work completed focused on thorough and exhaustive designs, and implementation of component parts. This work included developing a power management application, the serial communications required to relay information, customizing the operating system, and developing a trustworthy timing system. The power management application must monitor the state of the battery, the output of the solar panels, as well as control the amount of power provided to each of the primary systems. Serial communications are used to access external resources such as memory devices and a smart battery monitor. A minimal operating system was used to manage the various applications. Finally, an external real time clock and watch dog timer were used to enhance the reliability of the system.

A workstation requires a low-power design similar to a typical PC. In this paper we propose several strategies to reduce the power consumption of a workstation. First, we must comprehend the needed dynamic power management for the CPU by using a PWM (Pulse Width Modulation) chip to detect the workload or the current consumption of the CPU. The design then automatically adjusts the CPU voltage and the operating frequency to save power. Second, we design the chipset and memory and include a power saving control. Third, we provide the design with phase switching of the power switch to save power. The number of phases of a power switch can be controlled and is based on the loading of the CPU. The different loading of the CPU presents different power efficiencies of the VRM (Voltage Regulator Module), hence we design a power switch which can automatically change phases in order to obtain greater efficiency in power saving. Fourth, in addition to saving power due to the S0 state, as we have examined the PC power states, such as the S3/S5 Standby power states, we have found that many peripheral devices don’t need electricity to maintain operation in these states. We therefore redesign the circuit to cut off the current and thus save more power. For example, we can disable the PCIE add-on card function in certain machine states to save power.

This paper presented the watermarking scheme for a GIS vector digital map using polygon area distribution. This approach focuses on the watermark embedding with the robustness against RST, data or layer cutting and rearrangement, and other geometric attacks. The GIS vector digital map consists of various layers with spatial data and attributes data. Firstly, the proposed algorithm selects randomly the target layer with high polygon distribution and generates the set of polygon data group according to the sampled area distance. Secondly, the proposed algorithm embeds the binary watermark into the local mean area of polygon data group by changing vertices that are included in all polygon data. Experimental results verified that the proposed algorithm has the robustness against the above geometric attacks and the invisibility of the watermark.

The block based full search algorithm has been widely used for motion estimation in video coding, but it has the serious problem of significant computation requirements. In order to reduce the computation, this paper proposes a novel partial distortion search algorithm which reduces the computation of each distortion measure instead of number of checking points by using partial distortion search. In this algorithm, the entire macroblock is divided into different sub-blocks and the calculation order of partial distortion is determined based on the complexity of sub-blocks. A lossy algorithm is also presented by adaptively changing the early termination threshold for the current accumulated partial sum of absolute difference value. Experimental results show that the proposed lossless and lossy algorithm can significantly saves about 60% and 70% of the total computational costs, respectively. PSNR degradation of lossy algorithm is very negligible which is about 0.016 dB.

A new set-membership affine projection (SM-AP) algorithm for adaptive filtering applications is proposed. The new SM-AP algorithm eliminates the error-bound estimation problem of the conventional SM-AP algorithm. The poor tracking performance in nonstationary environments of the conventional SM-AP algorithm is also considered. A solution to this problem is proposed by incorporating a switching mechanism in the proposed SM-AP algorithm. The new SM-AP algorithm has better convergence efficiency and yields lower misadjustment than the conventional AP algorithm. On the other hand, with the switching mechanism it has better convergence efficiency and yields lower misadjustment than the conventional SM-AP algorithm in nonstationary environments.

A new Current Feedback Amplifier (CFA) suitable for low power VLSI applications is presented in two different designs to serve both low bandwidth (LBW) and high bandwidth (HBW) applications. The new circuit is employing positive current conveyor followed by amplifier followed by buffer to achieve vey high trans-impedance for this CFA circuit without needing to stack many transistors together and at the same time to use the whole bandwidth range. The proposed circuit is designed and simulated using 90nm technology kit in cadence. The bandwidth of the LBW circuit is approximately constant at 32MHz and for HBW is around 107MHz.

Advances in hardware technology, and wireless network have led to widely usage of implantable wireless micro-systems. However, they still present many challenges in different applications, mainly due to the size constrains and limited available power. In this work, the simulation results of a low voltage CMOS 180nm passive analog front-end circuit intended for powering implants are presented. The 2.4GHz ISM band frequency is employed for transmitting power. The RF signal is converted to a DC power by a charge pump circuit and stabilized at 1V by a voltage regulator. At the same time, the data signals are transmitted through the Medical Implant Communication Service (MICS) band. Subsequently, a low noise amplifier (LNA) with a voltage gain of 16.48dB at 1V is implemented to recover the data signals.

This paper provides guidelines in the form of a sequence of steps for optimization of step-up dc-dc converters using models derived from first and second order circuit equations. The models have been developed for three degrees of damping in the solution of the second order differential equation. Design issues for each case are discussed to obtain an optimized design. With specifications of input voltage, output voltage and power provided, the designer can employ the models to select appropriate component values and optimize circuit performance.

Abstract—In this paper, a high frequency soft switch DC/DC converter is proposed for power semiconductors (e.g., GCT, GTO). The proposed design includes six Parallel Isolated Power Supplies (PIPS), each supplying a GCT gate driver at regulated 20Vdc. Unlike self-powered supply which is design for powering up the switch gate driver for only one specific converter topology such as CSR, VSR, VSI, etc., our design features a general power supply for powering the gate drivers of switches used in different converter topologies where high voltage insulation level is required, such as Medium Voltage Neutral Point Clamped to PWM CSI converters. One isolated power supply is currently being tested for a 40W output power while operating with a switching frequency of 120kHz. This has been made possible while ensuring zero voltage switching (ZVS) for the main converter within the power supply. Since PIPS operates in ZVS, the switching losses are low and hence the efficiency of the proposed converter is high. Design of the converter and transformer with multiple outputs are verified by simulation and experimental results. Based on the comparisons with other existing converter configurations, we show that PIPS achieves high efficiency, and significant reduction in the cost and size of the power supply.

Abstract—In this paper, self-powered supply (SPS) techniques for gate drivers of different high power switches such as SCRs, IGBTs, GTOs, IGCTs, MOSFETs, and ETOs are surveyed. System configurations and operation principles of selected proposals in the literature are demonstrated. Compared to the external power supplies, SPSs bear the advantages of lower system cost and size, and increased reliability of power devices. The merits and drawbacks of some techniques are also discussed.

Shunt capacitors are extensively used in power system for reactive power compensation. Due to the existence of harmonic sources such as arc furnaces, harmonic-producing loads the possibility of harmonic resonance significantly increases. Switching shunt high voltage capacitors may cause over- voltages and this may damage the equipment considerably. In this paper the voltage profile and power losses in the sub-transmission network under study before and after installation of two high voltage shunt capacitors are compared. The harmonic analysis is employed to determine harmonic indexes such as HD in the network buses and to compare the capacitor loading limits with IEEE standard. The effect of the capacitor size on the resonance frequency is determined by using scan frequency analysis. Results show that the resonance frequency may occur in the lower frequency range with respect to the size of shunt capacitors. By considering the exact electromagnetic transient modeling of the network equipment, over-voltages during back to back switching of capacitor banks are also compared with the equipment characteristic.

This paper investigate the effect of using heterogeneous mobile terminals (e.g. single-mode, dual-mode, triple-mode, etc.) on call blocking and call dropping probabilities in next generation wireless networks (NGWN) . We develop an analytical model for heterogeneous mobile terminals in NGWN. Using a two-class three-RAT heterogeneous wireless network as an example, the effect of using heterogeneous terminals in the network is evaluated. Results show the overall call blocking/ dropping probability experienced by subscribers in heterogeneous wireless networks depends on the capabilities of mobile terminals used by the subscribers. In the worst case scenario, when all subscribers use single-mode mobile terminals, each subscriber is confined to a single RAT and consequently, joint radio resource management in the heterogeneous network has no improvement on new call blocking and handoff call dropping probabilities. However, in the best case scenario, when all subscribers use three-mode terminals, new class-1 call blocking probability decreases from 0.37 (for 100% single-mode terminals) to 0.05, at the arrival rate of 6 calls per minute. New class-2 call blocking probability also decreases from 0.8 to 0.52. Similarly, handoff class-1 call dropping probability decreases from 0.14 to 0.003, and handoff class-2 call dropping probability decreases from 0.44 to 0.09

In this paper, we determine the channel capacity of 60GHz wireless communications over additive white Gaussian noise channels. The channel capacity with phase shift keying (PSK) is investigated under FCC power constraints for the unlicensed 59-64GHz radio spectrum. It is shown that the capacity of 60GHz wireless communications is a function of distance and signal to noise (SNR) ratio, which demonstrates a fundamental trade-off for 60GHz system design. 60GHz system capacity is also compared to the capacity of Ultra Wideband radio system.

The microstrip patch antenna is a popular printed resonant antenna for narrow-band microwave wireless links applications such as radio frequency identification (RFID) systems that require semi-hemispherical coverage. In this paper, an 865 MHz microstrip patch antenna fed by a microstrip line designed on a substrate is considerably studied and thoroughly analyzed. The antenna has been designed using the 3D High Frequency Structure Simulator (HFSS). The initial design provides a gain of 4.2 dBi, while the final optimized design achieved a total antenna gain of 5.6 dBi and a return loss or reflection coefficient (S11) of -35dB at 865 MHz for 116 mm patch length. Modeling and optimization of the presented microstrip patch antenna has produced results that are suitable for RFID applications.

A complex system is expected to show different nominal behaviors under different conditions, and the deviation from these nominal behaviors is an indicator of potential faults. The nominal behaviors are either default working states, or learned patterns from extensive historical data. Based on nominal behaviors, change detection is utilized for diagnostics, especially on soft failures. A new technique, the inverse data transformation, is proposed in this paper, which simplifies the abnormality detection with a scaler decision threshold, and the fitting needs to be done only once; otherwise in direct deviation method, multiple curve fittings are required and the decision boundaries are curves, making the decisions on irregularly shaped decision regions difficult and inefficient. Wind turbine’s power curve analysis is utilized as the application example of this technique. Three functions are experimented for nominal behavior fitting, and Gaussian CDF function is selected in the inverse data transformation method for its fitting accuracy and one-to-one mapping property in inversion, comparing to Sigmoid function fitting and polynomial function fitting. In the fittings by Sigmoid function and Gaussian CDF function, the models are extended by adding two extra degrees of freedom accounting for shifting. The dynamic fitting is optimized by particle swarm optimization (PSO). Due to the random nature of PSO, multiple trials are carried out, and the parameter variation is small, only from the 9th digit. The states defined by Gaussian CDF method match the real data evenly in the middle region of the power curve, and it describes both the lower and upper kink regions in the power curve consistently. A diagnostic scheme is presented at last to illustrate the usage of the inverse data transformation.

In this paper, A particle swarm optimization (PSO) based multilateration algorithm is presented for a sensor network using UWB modulation. The PSO uses less energy and slightly less error than the traditional iterative least square approach making it a good choice for a wireless network of small devices. The PSO multilateration algorithm really improves localization error over the one step least square algorithm. This new multilateration algorithm can be used anywhere other multilateration algorithms are currently used with good results.

In this paper, we propose a method using mean-field neural networks to solve the placement problem for the layout design of analog integrated circuits. By means of the energy function, our method can not only meet the basic requirements of placement, but also handle the symmetry and proximity constraints that are special for analog layouts. Compared with other work, our experimental results show this proposed optimization scheme can achieve more efficient performance and obtain optimal solutions.

Extreme ultraviolet (EUV) radiation with wavelengths of 11 to 14 nm is seen as the most promising candidate for a new lithographic technology. Compared to synchrotron radiation sources and laser produced plasmas, gas discharge produced plasma (GDPP) sources for EUV radiation are expected to offer lower cost of ownership. This paper describes the dependence of EUV emission on gas flow rate. Using xenon a broadband emission in the investigated wavelength range from 10 to 18 nm is observed. Very short current pulses were applied across the xenon-filled Z-pinch capillary(3 mm diameter and 5 mm length) to produce EUV radiation. A EUV radiation from the Z-pinch plasma was characterized, which is based on the temporal behavior of EUV intensity and the pinhole images.

In this paper a dual crypto-processor for elliptic curve cryptography has been proposed. The proposed architecture can perform two independent scalar multiplications in parallel over GF(2^m). Although in this crypto-processor two independent scalar multiplications are performed in parallel, no extra arithmetic unit is employed in this crypto-processor (except an addition unit). Thus the architecture includes a field multiplier, a field divider, a field squarer and two field adders over the extension field with the degree of 163, which could perform complete arithmetic operations for elliptic curve cryptography. In this crypto-processor two scalar multipliers are synchronized and no conflicts occur in using the arithmetic units (during the execution of scalar multiplication). The implemented results of the Synchronized Dual Elliptic Curve Crypto-processor show that two scalar multiplications could be performed in1.95 msec, (in XC3S1500 platform) while one scalar multiplication takes approximately the same time for this crypto-processor.

We describe our development of a road traffic multi CA (Cellular Automata) model of the four most common types of 4-way intersection (Yield-controlled intersections, Stop-controlled intersections, Signal-controlled intersections, and Roundabout-based intersection). We developed this model to study how these four different types of 4-way intersection affect road traffic flow & congestion in general and “travel time” in particular. In this paper, we focus in particular on the mathematical algorithm, on the model abstractions, and on the simulator architecture. We adhere as much as possible to the CA paradigm as a way of avoiding hard to detect inconsistencies that could invalidate the model and the results obtained by using it.

This paper presents an automata-based approach for analyzing traces generated by the kernel of an operating system. We identified a list of typical patterns of problematic behavior, to look for in a trace, and selected the most convenient language to describe them. These patterns were then fed into an off-line analyzer which efficiently checks for their occurrences even in traces of several gigabytes. The checker achieves a linear performance with respect to the trace size. The remaining factors impacting its performance are discussed.

If UML is formalized with dynamic semantics, automatic verification can be performed for system model in the early stage of software procedure. It becomes more and more important to apply model checking in UML, such that software architecture can be formalized with dynamic semantics. We explicitly proposed the mapping rules between UML state diagram and Kripke structure semantics. UML state diagram is mapped to the value transition of variable rather than the transition of states, thus the situation in that system finite state automata can’t be exhausted can be resolved. Finally, a critical resource competition example is illustrated according to the theory. The mapping rules we proposed are bi-direction, as a result,the theory can be applied in both forward software engineering in design phase and reverse software engineering in implementation phase.

The discrete formal FRFT is hardly obtained by the directly sampling the continuous FRFT because the kernel function of the continuous fractional Fourier transform (FRFT) exists drastic oscillation and the oscillation amplitude has the distinct difference from the different order of the FRFT. Discrete formal FRFT has been great investigated recently and many definitions of the discrete FRFT have emerged. In this paper, the multiplicity of discrete FRFT is presented according to the multiplicity of continuous FRFT and the discrete FRFTs are classified in term of its definition mode. Some of discrete FRFTs are demonstrated which kind of the continuous FRFT they correspond to. On top of, the problem of the discrete FRFT is analyzed and digital simulations are presented to verify the surprising phenomenon. The generalized discrete FRFT are presented finally.

In this paper a new efficient fractal based compression algorithm is proposed for electrocardiogram (ECG) signals. The self-similarities in the ECG signals make them suitable to be compressed efficiently using fractal based methods. In the proposed scheme, as in the basic fractal based compression method, each part of the signal is mapped to another part with a reasonable error. The transforms performing the maps are stored instead of the signal samples. The signal is built up using these transforms in an iterative process using an arbitrary initial signal. Here mainly the morphological information of ECG is incorporated to improve the compression algorithm both in compression ratio and PRD (Percent of Root-mean-square Distance) and CC (Cross Correlation). As a novel point and in contrary to other schemes there is no need to detect the complexes of the ECG, This makes the algorithm more robust and accurate. The fixed block sizes with differentiating in higher steps for rapidly varying and remaining constant for less slope parts, rotated transforms and utilizing optimal coefficients for the maximum similarity between blocks is employed. The proposed algorithm is tested on a reasonable set of MIT-BIH database signals. The experiments all show that the proposed algorithm outperforms all reported Fractal_Based Schemes.

In this paper a new prediction method is proposed for compression of RNAi images. The large number of RNAi images that are produced, from experiments on biological cells for diagnosis and prognosis of diseases, require special compression methods. Images are segmented so that the boundaries of the cells are recognized form the smooth areas. The proposed scheme adaptively changes its function to exploit the spatial features of the cell boundaries and the smooth regions. The proposed predictor has either better performance and comparable complexity, or it has lower complexity and comparable performance, when compared to the existing predictors for this specific application.

A new compression method is proposed in this paper which uses the contourlet transform. The proposed algorithm, unlike non-linear approximation (NLA) methods, modifies the coefficients in a controlled manner. This is performed in such that the difference between a modified coefficient and its original value is within a certain range. At the same time the modification is performed with the goal of minimizing the entropy of the coefficients. The implementation results show that our method produces images with higher PSNR, for similar bit-rate conditions, as compared to NLA compression algorithms. Furthermore, the visual quality of the images produced by our method is higher than the mentioned NLA algorithms. The implementation results also show the superiority of our method over WBCT algorithm which is based on the joint application of wavelet and contourlet transforms.

Motion estimation is a critical part of any video coding scheme. Block matching schemes, though being easy to implement, could produce poor results when multiple moving objects exist in one block. In this paper a new mesh-based algorithm is presented which uses affine transforms. The algorithm searches for codirectionality among pixels of a mesh element. When objects pass each other in a scene the superiority of the proposed algorithm is more apparent. The results from implementation of the proposed algorithm show its overall advantage in most instances with respect to comparable algorithms of its class.

Content base image retrieval is an important research field with many applications. This paper presents a new approach for finding similar images to a given query in a general-purpose image database through content-based image retrieval. Color and Texture are used as basic features to describe images. In addition a binary tree structure issued to describe higher level features of an image. It has been used to keep information about separate segments of the images. The performance of the proposed system has been compared with the SIMPLIcity system.

This paper proposes a two-stage approach to reconstruct the map of a scene given tagged photographs of that scene. In the first stage, several methods are proposed that transform tag data from photographs into an intermediate distance matrix. These methods are compared against each other. In the second stage, a method based on the physical mass-spring system is proposed that transforms the distance matrix into a map. It is compared against and outperforms MDS-MAP(P) given human-tagged input photographs. Experiments are carried out on two test datasets. An evaluation method is described and the optimal overall reconstruction generates maps with accuracies of 47% and 66% respectively for the datasets, both scoring 40% higher than the average random reconstruction. The proposed approach is applied to three sample datasets, and upon a qualitative inspection, the resulting maps show that they are able to convey the high-level organization of the scenes.

The steadily growing share of converter connected distributed generations have been receiving more attention in the last few years because of their high efficiency and superior reliability. This paper presents a novel remote power control method of a small single phase grid connected inverter using a DC-DC converter and an ADR101 serial data acquisition card. Before grid connection characteristics of the inverter are programmed for a desired input DC voltage versus output power. Input dc voltage of the inverter is adjusted by controlling the DC-DC converter. A PC receives the required output power signal from a dispatch center via the Internet. The PC measures the power being fed by the inverter to the grid and uses an ADR101 to control the dc-dc converter to adjust the power flow to the grid. This paper presents the control scheme and test results of a 250W grid connected inverter.

This paper deals with discrete-time multivariable feedback systems that are subject to sensor time delays. Supposing a controller exists that provides good performance without sensor delays, we consider how an estimator can be used to recover closed-loop performance when sensor time delays are introduced into the feedback loop. Using separation principle arguments, we first show that stability and tracking performance can be recovered for a broad range of estimators, and then we determine how disturbance rejection and sensor noise rejection properties of the (delayed) closed-loop system are related to those of the original (undelayed) closed-loop system and those of the estimator.

A novel oil & water mixture sensor has been developed recently in the INCA lab. In order to analyze the sensor’s accuracy and robustness under various conditions, we have developed a miniature multi-phase flow loop. The loop features two precision gear pumps and a gravity based separator. The pumps are controlled by a Linux PC based data acquisition card. This allows for an integrated uniformation of the calibration processes.

A framework for supervisory cooperative estimation in multi-agent linear time-invariant (LTI) systems is presented in the companion work (Part I). We introduced a set of sub-observers such that each estimates some states with a given set of input, output, and state information. A discerete-event system (DES) supervisory control framework is used for cooperation among the sub-observers. The supervisor selects a set of sub-observers to successfully estimate all states of the multi-agent system. In addition, in presence of a fault in the system, the supervisor reconfigures the set of selected sub-observers to minimize the fault impact on the estimation performance. Our general framework can be applied to any multi-agent system including industrial processes. In the companion paper (Part I), our proposed framework for the supervisory estimation is developed based on the notion of sub-observers and DES supervisory control. In this paper (Part II), a DES-based combinatorial optimization method for selection of an optimal set of sub-observers is presented, the feasibility of the overall integrated sub-observers is validated, and the application of our proposed method in a practical industrial process is demonstrated through numerical simulations.

In this work, we propose a framework for supervisory cooperative estimation of multi-agent linear time-invariant (LTI) systems. We introduce a group of sub-observers, each estimating certain states that are conditioned on given input, output, and state information. The cooperation among the sub-observers is supervised by a discrete-event system (DES) supervisor. The supervisor makes decisions on selecting and configuring a set of sub-observers to successfully estimate all states of the system. Moreover, when certain anomalies are present, the supervisor reconfigures the set of selected sub-observers so that the impact of anomalies on the estimation performance is minimized. This framework is applicable to any multi-agent system including large-scale industrial processes. In this paper (Part I), our proposed framework for supervisory estimation is developed based on the notion of sub-observers and DES supervisory control. In the companion paper (Part II), a DES-based combinatorial optimization method for selection of an optimal set of sub-observers is presented, the feasibility of the overall integrated sub-observers is validated, and the application of our proposed method in a practical industrial process is demonstrated through numerical simulations.

A novel formulation of quarter-symmetry SHE-PWM problems for five-level voltage inverters is proposed. The SHE modulation scheme features a broad solution space and can eliminate a large number of low-order harmonics. An effective method for obtaining initial values of switching angles is proposed. This method is based on rules of equal area and superposition of barycenter of the PWM section with a sine-reference signal. To illustrate the effectiveness of the proposed SHE method, a five-level voltage source inverter with elimination of 11 low-order harmonics is investigated. The SHE-PWM equations that can eliminate harmonics from 5th to 35th with modulation index M varying from 0 to 1.15 are formulated, and solutions are presented. Simulations and experiments based on several sets of solutions are carried out. It is demonstrated that the experimental results agree well with simulated ones, which proves the validity and practicability of the new method proposed.

This paper presents the small signal model and closed loop control design using average current control for an L-L type active-clamped zero-voltage switching (ZVS) current-fed isolated DC-DC converter. State-space averaging technique is used to derive the small signal model. The controller is designed for fixed-frequency duty cycle modulation and works for wide input voltage and load variation. A complete design procedure is presented. Frequency response curves are obtained at different input voltage and load conditions to verify the stability and design, and to evaluate the performance of the controller. Simulation results for step changes in input voltage and load are given to check the transient response of the converter.

This paper presents the development and performance testing of a new switching strategy for single-phase ($1\phi$) voltage-source (VS) AC-DC converters. The proposed switching strategy is based on employing scale-based linearly-combined wavelet basis functions and their dual synthesis ones for switching $1\phi$ 4-pulse bridge AC-DC converters. The employed wavelet basis functions are meant to sample a DC reference signal in a non-uniform recurrent manner, then reconstruct it using the AC-DC converter's switching actions. The output of such an AC-DC converter is found to contain low harmonic contents along with a unity input power factor.

I-V characteristic of a solar array is very important for the design and long-term performance evaluation of a photovoltaic (PV) generation system. Manufacturers provide only I-V characteristic of (PV) modules at standard conditions in Lab. However, a PV generation system will operate at a widely variable environment conditions. Besides, the different combinations of PV Models in series and parallel may give rise to some energy loss because of nonuniform characteristic of individual PV modules. Therefore, accurate performance evaluation of a PV station faces great challenges. This brings about great needs for fast field testers for I-V characteristic of the solar array. This paper presents capacitor charging schematic for fast field testing of I-V characteristic of solar arrays. A prototype based DSP TMS320F2806 is designed and manufactured. The prototype is featured in automatic pre-estimated measurement scale by the theory model of I-V curve, and digital filtering of sampling data. The field experiment results show that the testing system operates stately, and with high measurement accuracy and speed. A complete testing procedure only takes about 10s, and the measured I-V characteristics of solar arrays can be displayed on LCD directly in the form of a curve.

Abstract: This paper presents detailed analysis to compare and evaluate the performances of four control strategies for extracting the reference currents of shunt active power filter under distorted and unbalanced source and load conditions. The four controllers are based on instantaneous reactive power (p-q), d-q coordinate formulation (d-q), unity power factor (UPF), and perfect harmonic cancellation (PHC) strategies. Detailed analysis and simulation results (performed with Simulink\Matlab) are used to highlight the advantages and limitations of each control approach.

In recent years, there has been a strong interest in incorporating multihop relaying strategies in cellular systems to develop Multihop Cellular Networks (MCNs). This increases the network capacity, improves its coverage and reduces transmit power levels. In this paper, a joint relay selection and resource allocation algorithm is proposed to maximize the throughput. The proposed algorithm is evaluated and compared with three other existing algorithms. Simulation results show that our proposed algorithm achieves at least 30% more throughput than those of others when there are 10 active users in the cell.

Abstract – This study focuses on the investigation of microwave scatter for data transmission relay to extend the signal coverage whether indoor or outdoor for non-line-of-sight (NLOS) applications. This provides an economic solution to improve broadband access to subscribers in remote places. A series of CW measurements over 29-30 GHz was conducted indoor at an intersection of two hallways in presence of a microwave scatterer such as flat surface metallic reflector. Also measurements were carried outdoor to target an office building in the campus of the CRC. Whether indoor or outdoor, Results show that microwave scatter provides better signal coverage and data throughput. Its strength depends strongly on the scatterer’s type and surface. Results also indicate that, for systems operating at a short range, microwave scatter provides an alternative to LOS systems, cables or the use of retransmission systems. The measurement system involves a new evolutional method of providing phase coherence between transmitter and receiver where both transmitter and receiver are connected by means of a single-mode optical fiber cable.

The purpose of this paper is to introduce a model intended to capture the behavior of the wireless channel at time scales which are related to packet transmission times. In this approach it is assumed that the prime factor affecting the data rate selection is the path attenuation. We model the wireless channel using a multistate process where each state corresponds to the nominal data rate achieved by the station when it uses a particular combination of modulation and coding (i.e., adaptive modulation). Differently from other proposals, in this model state changes are created from mobility assumptions. We illustrate the use of this model with a case study.

To mitigate the single-event effect, improve the stability and also maintain the low power characteristic of sub-threshold SRAM, a Dual Interlocked Storage Cell (DICE) based SRAM cell in 90nm CMOS technology was proposed to eliminate the drawback of conventional DICE cell during read operation. In order to make the proposed SRAM cell work under different power supply voltages from 0.3V to 0.6V , an improved replica sense scheme is applied to produce a reference control signal, with which the optimal read time could be achieved. In this paper, a 256 * 8bytes SRAM core was simulated and the operating frequency at VDD = 0:3V is up to 4.7MHz with power dissipation 6.0uW, while it is 45.5MHz at VDD = 0.6V dissipating 140uW. The layout of SRAM core was also done in 90nm CMOS technology.

This work presents a Field Programmable Gate Array (FPGA) implementation of the Min-Sum iterative de- coding algorithm for the (8,4) extended Hamming code using a reconfigurable computing system. The Mitrion-C high level language (HLL) is used to program the FPGAs, since it provides flexible tools for FPGA-based prototyping and func- tional verification for hardware design. A hardware-efficient implementation of the Min-step in the Min-Sum decoder, which eliminates the use of floating point multipliers, is also presented. The parallelism offered by the Min-Sum algorithm is exploited in hardware, resulting in a 15 fold speedup over optimized software implementations. The performance of the hardware implementation is virtually the same as that predicted by computer simulations, validating the hardware design.

In this paper, we present a new block cipher, referred as PUFFIN2, that is designed to be used with applications requiring very low circuit area. PUFFIN2 is designed to be implemented exclusively with CMOS technologies and in a serialized architecture, so that the maximum reuse of hardware components is achieved resulting in a very compact implementation. PUFFIN2 has a block size of 64 bits and a key size of 80 bits. Compared with a serialized implementation of cipher PRESENT, which has the same block size and key size and is claimed as the smallest practical block cipher implementation to date, our cipher has 17% fewer gates using the same CMOS technology. Further, PUFFIN2 inherently supports both encryption and decryption while the serialized PRESENT is an encryption-only implementation.

Bulk-driven MOSFET technique meets the low-voltage and low-power requirements demanded in the modern analog circuit design. Due to submicron/nanometer technologies and critical short-channel effects, choosing a suitable MOSFET model for circuit design becomes increasingly important. However, the conventional MOSFET models normally set up for the typical gate-driven applications may not perform correctly and accurately for the bulk-driven applications in the advanced technologies. In this paper, three most widely used MOSFET models, including BSIM, EKV, and PSP, have been extracted for the modern technologies and used in the simulation of bulk-driven applications. Measurement data of fabricated devices are compared with simulation results from distinct models. Several critical MOSFET parameters have been chosen to compare and analyze MOSFET characteristics. The experimental results demonstrate the advantages of the bulk-driven technique compared with the gate-driven scheme. Finally, the performance of distinct MOSFET models is summarized in order to provide analog circuit designers with practical directives.

Implementation of a high quality spiral inductor on silicon substrate is a long lasting challenge for the microfabrication researchers; in this paper a new spiral inductor which is compatible with the standard IC technology is proposed.This new inductor shows more quality factor and higher resonance frequency even though the overall inductance value remains almost the constant in compare with the traditional designs. This new structure shows more improvement in the peak of quality factor as the number of turn increases.

Le but d'un système de détection passive cohérente est de récupérer l'écho provenant de la réflexion sur la cible à détecter. La méthode par analyse propre basée sur la projection de signaux dans un sous-espace orthogonal au signal direct permet de pallier le problème d'interférence qu'engendre la présence du signal en trajet direct dans ce type de système de détection. Dans le cas de la présence d'un écho et du signal direct, l'étude de la distribution des puissances de chaque signal par l'analyse de la variation des valeurs propres en fonction du nombre d'éléments du réseau d'antennes ou du nombre de sous-réseaux démontre que ces signaux demeurent cantonnés dans leur sous-espace orthogonal respectif sans influencer de manière importante l'autre sous-espace.

The accuracy of direction finding (DF) systems can often be improved by using techniques for the time averaging of information from multiple data records, particularly when the signal-to-noise ratio is low. One approach used for DF involves the computation of the emitter angle of arrival (AOA) from the phase angle of a complex-valued signal. For this type of system, there are two closely related but distinctly different approaches to AOA data averaging. The first approach directly averages the complex signal values and only then computes the value of AOA from the phase angle of the resultant averaged signal. The second approach reverses the order of operations of the first approach by first computing the phase angle of each signal sample and then averaging the computed individual phase angles. Experiments with off-the-air data have indicated that the first approach is preferable. This paper gives a theoretical proof for this result given the assumption that the complex data sequence processed by the AOA estimator is i.i.d. Gaussian distributed.

The additional estimation error introduced by the use of finite ground planes is evaluated numerically for two types of conventional direction finding (DF) systems. The analysis reveals that commonly accepted ground plane dimensions result in degraded estimation accuracy when the incoming signals are of unknown polarization.

Exact numerical procedures for computing the normalized detection threshold for the FFT J-out-of-L detector are presented. Accurate approximations are also provided for cases where numerical procedures break down due to rounding errors. Some of the numerical procedures detailed here are also useful in other signal processing problems.

An important idea for improving the practical performance of direction finding (DF) systems involves the use of calibration tables. These are generally based on experimental measurements of systemic errors obtained using a known signal to illuminate the antenna. However, the accuracy of the calibration data, and therefore that of the system, is affected by various error mechanisms. This paper uses full-wave analysis to investigate the errors resulting from a spherical wave front and from ground reflections when experimental methods are used to produce calibration data. These results show that the distance between the calibration source and the DF system should be larger than has been previously believed and that additional restrictions on the operating frequency ranges of the DF system may be necessary when experimental calibration data is used.

In the future, autonomous Unmanned Aerial Vehicles (UAVs) need to work in teams to share information and coordinate activities. The private sector and government agencies have implemented UAVs for homeland security, econnaissance, surveillance, data collection, urban planning, and geometrics engineering. Significant research is in progress to support the decision-making process for a Multi-Agent System (MAS) consisting of multiple UAVs. This paper investigates fundamental issues in path planning for multiple UAVs. MASs with multiple UAVs are typical distributed systems. We propose to use genetic algorithms to plan multiple paths for multiple UAVs. Simulation technologies have become important to the development of aerospace vehicles. In this research, we verify the proposed path planning approach using Matlab. Simulation results demonstrate that the proposed approach is able to plan multiple paths for UAVs successfully.

le travail présenté dans ce papier consiste à présenter une méthodologie de commande neuronale d’un processus dynamique non linéaire. Cette technique est appliquée à une soufflerie de séchage installée dans un laboratoire de la Faculté des sciences de Tunis. Le modèle neuronale de la dynamique inverse est entraîné avec une base d’apprentissage puis testé et validé avec d’autres mesures pratiques.

L’information est une ressource essentielle dans les activités quotidiennes de notre vie socio-économique. L’information est principalement collectée, manipulée, préservée et diffusée sous un format numérique. Ceci l’expose aux problèmes reliés à l’utilisation des technologies de l’information et de la communication. La présence d’une vulnérabilité dans un système informatique peut avoir un impact plus ou moins important sur la sécurité de l’information : perte, vol, modification, falsification … Afin de prévenir ces types de situations, il existe de nombreuses méthodes d’analyse des risques de sécurité, permettant de faire un audit complet du système d’information et d’émettre des recommandations de correctifs en conséquence. D’autre part, des normes de sécurité ont été mises au point afin d’établir des règles de sécurité précises et de donner une certification aux systèmes qui respectent l’ensemble de ces règles. Cependant, les méthodes de gestion des risques actuelles tentent d’aider à les évaluer, à implanter des contrôles appropriés, à se conformer aux règlements et aux lois de protection de l’information et de la vie privée, sans toutefois être complètement compatibles avec les normes en vigueur. Ce document a pour but de présenter, sur la base de certains critères, les résultats d’une étude sur différentes méthodes et normes de sécurité des systèmes d’information, utilisées en Europe et en Amérique du nord.

Utilizing aggregated electric loads as system resources has several benefits. It can provide ancillary services for power systems. At the same time, it can provide demand management for electricity customers. It is necessary to develop integrated control strategies for aggregated electric loads. Most domestic water heaters (DWHs) are electric and they consume much power especially in winter. DWHs represent a substantial share of the residential electricity consumption. Due to the energy storage capability of DWHs they are the best candidates for load control strategies. In this paper, we propose a novel centralized fuzzy controller for peak shaving of the power demand profiles. The proposed centralized controller does not sacrifice customers' convenience level. Simulation results show that the proposed centralized control strategy is effective in shaving the aggregated DWHs load demands while filling valleys of the aggregated load profile.

This paper formalizes the supervisory control of Fuzzy Discrete Event Systems (FDES) that can be effectively used in navigating mobile robots. In order to introduce a supervisor for FDES, the fuzzy controllable and uncontrollable events are defined. Here the uncontrollable events occur without the supervisory knowledge. Both controllable and uncontrollable events are triggered by the sensor readings and the inference occurs through fuzzy rule base system. The controllable events are fired only through supervisor while uncontrollable events occurs without any supervision. By this way the supervisor can activate and control fuzzy controllable events simultaneously with fuzzy uncontrollable events to achieve the planned objectives. The fuzzy observability concept is incorporated to show the existence of a fuzzy partially observation supervisor. The proposed theoretical development is then extended to discuss an application with behavior based control of mobile robots.

In the area of fault analysis, SDG (Signed Directed Graph) models can be used to describe the system states and the fault propagation paths which are the composition of qualitative deviation from the normal state. In control systems, besides the natural relations caused by the physical properties, the forced control actions determine the dynamic properties of the systems, which cause the particularity of SDG model-based analysis. In this paper, the SDG description and the analysis methods of fault propagation in control systems are presented, and the typical cases like PID control, feedforward control, split-range control, cascade control etc are illustrated. A graphical analysis method is proposed to substitute the algebraic methods based on equations. These results can be expanded to various control systems and even be applied to large-scale industrial systems by the combination and connection of several basic elements.

This paper sheds light on the concepts of decision making and optimal control in the supervisory control of hybrid systems. Here, “decision-making” is defined as “priority-setting,” meaning that we construct a priority mapping that is allowed to be defined from both policies and the system’s physical limitations. At the run time, the supervisory control of any hybrid system results in a set of possible transitions for the current state from which one should be picked. However, the set may consist of more than one transition at the highest priority. In such a case, hybrid optimal control is defined to be applied. Therefore, the purpose of this paper is to highlight these stages of specification to be implemented through a novel multi-layer framework for the execution and control of hybrid systems.

An application of guardian maps to design a robust PI controller is presented. The PI is used to control a given first order system with known parameters. The guardian maps identify in the complex plane the regions where the application is stable. The objective is to select the controller’s parameters so that the closed loop poles are confined to a predetermined region in the complex plane. This region is built to insure desired performance such as rise time, overshoot, or response time, i.e. it insures robust performance.

The rotor of a typical water current turbine rotates below 100 rpm. In conventional hydro installation the generator is coupled to the turbine via a gear box, so that it can typically rotate at a speed of 1500 or 1800 rpm. The water current turbine can be simplified by eliminating the gear box and by using a low-speed generator, the rotor of which rotates at the same speed as the rotor of the turbine. The main design challenge for a direct driven Permanent Magnet Generator (PMG) is to minimize the cogging torque. Cogging torque is an inherent characteristic of PMGs and is caused by the geometry of the generator. In this paper a new approach to minimize the PMG cogging torque is proposed. Basic design of a low cogging torque generator is also provided.

Permanent magnetic electric machine (PMEM) is widely employed in variety of applications because of their numerous advantages beyond other electric machines. Cogging torque is caused by the reluctance change between the stator teeth and magnet poles on the rotor, it is an inherent characteristic of PMEM. In many applications, cogging torque has become one important design specifications and considering issue of PMEM. Study on cogging torque calculation methods and the cogging torque reduction measures are becoming more and more important nowadays. In the paper, the cogging torque calculation methods are introduced, and various practical cogging torque reduction measures are studied and compared.

Power from wind or water current can be extracted using a horizontal or vertical axis turbine. Vertical axis turbines are capable of extracting power from wind or water current regardless of the direction of flow. A hybrid turbine consists of two types of turbines on a same shaft. Such a design exploits good features of two turbines. This paper presents the design of a hybrid turbine based on a straight bladed Darrieus (lift type) turbine along with a double step Savonius (drag type) turbine. Four bladed Darrieus rotor is placed on top of a Savonius rotor. The hybrid vertical axis turbine has much better self-starting characteristics and better conversion efficiency at higher flow speeds. The hybrid turbine is built and tested in variable speed water currents. This turbine design can also be used as a wind turbine. This paper presents the system design and performance test results of the hybrid turbine. The designed hybrid vertical axis turbine will be used to generate power at the sea floor for an instrumentation system.

The paper presents a digital simulation and validation study of a novel control system for control of a Wave Energy Converter (WEC)-Battery renewable energy system for DC type loads. The performance and dynamic characteristics of the controllers to any load nonlinear J, B parameters and load torque is examined for PMDC Motor Drives. The proposed dynamic error driven control system is digitally simulated using the MATLAB/Simulink/SimPowerSystems software. The dynamic performance of the unified green energy Wave Energy-DC utilization system is examined for the proposed controller.

The advance in FPGA technology allowed embedding different types of resources on a single chip. These resources range from a simple look-up table to a complete processor. The resources available on the FPGA fabric allow building various hardware systems for different applications with several trade-offs in terms of performance and power consumption. This paper proposes six different architectures to implement VLSI maze routing algorithm on FPGAs. These architectures utilize two processors (MicroBlaze and Power-PC) and a separate hardware accelerator. The hardware accelerator was designed for the maze routing algorithm with two different protocols for data transfer. All architectures are evaluated based on seven benchmarks. The evaluation includes the performance and the power consumption of the architectures. This work demonstrate that the architecture composed of a soft-core processor directly connected to the hardware accelerator with fully utilized FIFO channel achieves the best power-delay product among all the investigated architectures.

Performance of analog circuits is highly sensitive to layout parasitics. This paper presents an improved algorithm that automatically conducts performance-constrained parasitic-aware retargeting and optimization of analog layouts. In order to meet the desired circuit specification, performance sensitivities with respect to layout parasitics are first determined. Then the algorithm applies sensitivity-based model to control parasitic-related layout geometries by constructing a set of performance constraints subject to maximum performance deviation due to parasitics. The formulated problem is finally solved using graph-based techniques and nonlinear programming. The algorithm has been demonstrated to be effective and efficient by successfully retargeting several operational amplifiers within minutes of CPU time.

As the precise wire length for a given placement can only be known after routing, accurate and fast to compute wire-length estimates are required by FPGA placement algorithms. In this paper, we describe a new model, called star+, for estimating wire length during FPGA placement. The proposed model is continuously differentiable and can be used with both analytic and iterative improvement placement methods. Moreover, the time to calculate incremental changes in cost from moving/swapping blocks can always be computed in O(1) time. When incorporated into the well-known VPR [1,2] framework, and tested using the 20 MCNC benchmarks [3], the results produced show that the star+ model achieves a 6-9% reduction in critical-path delay compared with HPWL, while requiring roughly the same amount of computational effort.

This paper presents a solution to handling multiple symmetry constraints in the placement design using transitive closure graph (TCG) representation for analog layouts. We propose a set of symmetric-feasible conditions, which can guarantee symmetric placement of sensitive cells with respect to multiple symmetry axes for reduction of parasitic mismatch and thermal gradients. We also develop a new contour-based packing scheme with time complexity of О(p∙nlgn), where p is the number of symmetric groups and n is the number of the placed cells. Furthermore, a set of perturbation operations with time complexity of O(n), where n is the number of the placed cells, are defined in order to generate a random symmetric-feasible TCG configuration from an existing one. Our experimental results show the effectiveness of this approach compared to other state-of-the-art placement algorithms.

A truly monolithic clock and data recovery (CDR) circuit for low-cost low-end data communication systems has been realized in 0.6μm CMOS. The implemented CDR comprises a phase-and frequency-locked loop using an I/Q ring VCO to recover clock from incoming non-return-to-zero (NRZ) data stream and a data decision circuit to retime the received data, respectively. The novelty of this design is that silicon-saving active inductors are used to improve the transmitted bit rate and the compatibility with digital circuits for monolithic integration, to reduce silicon area, while the excessive noise is suppressed by fully differential topology. The tested CDR IC achieves a locking range from 400MHz to 950MHz and a RMS jitter of 0.008 UI for a 622Mb/s pseudorandom bit sequence (PRBS) length of 2^31-1.

This paper presents a 10-Gb/s backplane transmitter with a finite impulse response (FIR) pre-emphasis equalizer to suppress inter-symbol-interference (ISI) at data centers and transition edges simultaneously. The design concepts are discussed. Circuits in 0.13µm IBM CMOS technologies are given. Comparison with conventional data center oriented equalizer and transition edge oriented equalizer are carried out on a 40-inch FR4 differential backplane.

This paper studies the effects of the design parameter on the efficiency of two-way Doherty power amplifiers driven by signals having high peak to average power ratio (PAPR). The optimal value of the design parameter is calculated as a function of the output power back-off for two WCDMA signals having a PAPR of 7.3 dB and 9.8 dB. It is shown that, for the considered signals, the optimal value of the design parameter depends only on the output power back-off. Parametric study demonstrated that while the optimal value of the design parameter results in high efficiency over a reduced power range, a judicious sub-optimal choice of the design parameter will lower the peak average efficiency but considerably increase the high efficiency power range of the Doherty amplifier.

This paper presents a programmable pre-cursor ISI equalization circuit for high-speed serial data transmission over highly lossy electrical backplane channels. Although decision-feedback-equalizer (DFE) provides an effective way to compensate various channel impairments, such as frequency dependent loss, dispersion and reflections in the legacy backplane environment, for high-speed, highly lossy band-limited channel, the pre-cursor inter-symbol interference (ISI) is still a significant problem for channel equalization. A programmable pre-cursor ISI equalizer combined with a 3-tap DFE is implemented to work at 10-Gb/s and compensate the channel loss of -20 dB. The results show it outperform a traditional 5-tap DFE.