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Availability of a common, shared benchmark to provide repeatable, quantifiable, and comparable results is an added value for any scientific community. International consortia provide benchmarks in a wide range of domains, being normally used by industry, vendors, and researchers for evaluating their software products. In this regard, a benchmark of untimed Petri net models was developed to be used in a yearly software competition driven by the Petri net community. However, to the best of our knowledge there is not a similar benchmark to evaluate solution techniques for Petri nets with timing extensions. In this paper, we propose an evaluation framework for the comparative analysis of generalized stochastic Petri nets (GSPNs) simulation techniques. Although we focus on simulation techniques, our framework provides a baseline for a comparative analysis of different GSPN solvers (e.g., simulators, numerical solvers, or other techniques). The evaluation framework encompasses a set of 50 GSPN models including test cases and case studies from the literature, and a set of evaluation guidelines for the comparative analysis. In order to show the applicability of the proposed framework, we carry out a comparative analysis of steady-state simulators implemented in three academic software tools, namely, GreatSPN, PeabraiN, and TimeNET. The results allow us to validate the trustfulness of these academic software tools, as well as to point out potential problems and algorithmic optimization opportunities. [ABSTRACT FROM AUTHOR]

This paper presents the details of JFETIDG, a compact model for independent dual-gate junction field-effect transistors with any combination of p-n junction or MOS gates. JFETIDG accounts for nonlinearity from depletion pinching, velocity saturation, and self-heating, and includes extensive modeling of geometry and temperature dependences, parasitics, noise, and statistical variations. We also demonstrate that it accurately models long channel junctionlessMOS transistors. Themodel is verified by comparison with TCAD simulations and experimental data. Verilog-A code for JFETIDG is available in the public domain. [ABSTRACT FROM AUTHOR]

This paper presents a method to estimate the inverter lifetime so that we can predict a failure prior to it actually happening. The key contribution of this study is to link the physics of the power devices to a large scale system simulation within a reasonable framework of time. By configuring this technique to a real system, it can be used as a converter design tool or online lifetime estimation tool. In this paper, the presented method is applied to the grid side inverter to show its validity. A power cycling test is designed to gather the lifetime data of a selected insulated gate bipolar transistor (IGBT) module (SKM50GB123D). Die-attach solder fatigue is found out to be the dominant failure mode of this IGBT module under the designed accelerated tests. Furthermore, the crack initiation is found to be highly stress dependent while the crack propagation is almost independent with stress level. Two different damage accumulation methods are used and the estimation results are compared. [ABSTRACT FROM AUTHOR]

This paper presents a new three-phase phase-locked loop (PLL) system that primarily estimates the phase angles, frequency, and magnitudes of the a three-phase input signal and also provides a filtered version of the input. It is then extended to the estimation of sequence components, their magnitudes, and phase angles. As compared with the conventional three-phase PLL, this method does not suffer from errors that are caused by signal unbalance and dc offset. It also provides estimate for several other variables which are not included in the conventional three-phase PLL. As compared with the method of using three independent single-phase enhanced PLLs, the proposed method offers a simpler structure. Moreover, the estimated frequency is more accurate and smoother because it uses the information from all three phases to estimate a single value for frequency. The paper also presents a modification that makes the PLL parameters independent from the input signal amplitude. The same modification is applicable to existing methods such as conventional three-phase PLL. Simulation and experimental results are presented to confirm desirable performance of the proposed method. [ABSTRACT FROM AUTHOR]

This paper deals with a new family of high boost voltage inverters called switched-inductor quasi-Z-source inverters (SL-qZSIs). The proposed SL-qZSI is based on the well-known qZSI topology and adds only one inductor and three diodes. In comparison to the SL-ZSI, for the same input and output voltages, the proposed SL-qZSI provides continuous input current, a common ground with the dc source, reduced the passive component count, reduced voltage stress on capacitors, lower shoot-through current, and lower current stress on inductors and diodes. In addition, the proposed SL-qZSI can suppress inrush current at startup, which might destroy the devices. This paper presents the operating principles, analysis, and simulation results, and compares them with those of the SL-ZSI. To verify the performance of the proposed converter, a laboratory prototype was constructed with 48 Vdc input and an ac output line-to-line voltage of 120 Vrms. The simulation and experimental results verified that the converter has high step-up inversion ability. [ABSTRACT FROM AUTHOR]

This paper presents and discusses different approaches for the measurements of the shielding effectiveness of thick multilayered panels, based on the use of nested reverberation chambers. In particular, it is considered the case of thick multilayered panels, characterized by one highly reflecting face, like a protected composite laminate or a protected glazing window. The paper proposes a novel test procedure, which allows one to estimate from the measurement of a finite dimension panel, the shielding performance of an infinite material sheet against a reverberating field. The method is validated by comparison with the results of analytical simulations and provides accurate results in a wide frequency range, above the lowest-usable frequency of the outer chamber. [ABSTRACT FROM PUBLISHER]

The west coast and islands of Taiwan have abundant wind resource, which offers a great opportunity for large-scale offshore wind power generation. In Taiwan, the first stage of the offshore wind farms at the Jhang-Bin and Penghu areas has been planned. In particular, the Jhang-Bin wind farm will become the first and one of the largest wind farms in Taiwan. Therefore, its impacts on system operation and security have to be investigated and studied in advance. Following a general connection design discussion, this paper is consist of four major system impact analyses: load flow, fault current, voltage variation, and transient stability. Moreover, three types of typical wind turbines have been adopted in this paper in order to compare their performances on the wind farm integration system. From the simulation results, some significant conclusion and recommendations have been extracted, which would contribute to the first offshore wind farm development in Taiwan. [ABSTRACT FROM AUTHOR]

3-D simulations of electromagnetic field by finite difference time-domain (FDTD) algorithm were helpful for analyzing propagations of electromagnetic wave. In industrial fields, FDTD simulations are necessary to design telecommunication devices. Furthermore, structures of photonic crystal and light transmissions in nanoscale–microscale structures of it were also actively studied and FDTD simulations are also utilized for designing of it. Many bioorganisms produce biophotonic crystals that have nanocyclic structures. For example, guanine crystals stacked in fish skin strongly reflect light to camouflage their body. Our group studies this crystal to apply for development of biogenic microoptical devices. In this paper, we analyzed light scattering on guanine crystal by FDTD simulations with model structure of the crystal. Rotating the crystal axis to the incident light, the direction of reflected light was simulated. Distributions of strength of light reflectance on the surface of crystal plane were also analyzed and compared with three kinds of incident wavelengths. Results suggested the relations of directivity of the reflected light with the incident angle of light irradiation to the crystal. [ABSTRACT FROM AUTHOR]

Conventional heaters used in microelectromechanical systems (MEMS) electrothermal displacement sensors typically feature a uniform cross section, which results in a nonuniform temperature profile. In this paper, electrothermal sensors with a shaped beam profile are introduced, with simulation results showing that a much flatter temperature distribution is achieved across the length of the heater. The proposed sensor design is implemented as the displacement sensor for a MEMS nanopositioner together with a more conventional electrothermal sensor design for comparative purposes. Experimental testing indicates that the shaped profile significantly improves upon the conventional sensor design in a number of areas, including sensitivity, linearity, and noise performance.\hfill[2012-0291] [ABSTRACT FROM AUTHOR]

Cooperative diversity exploits the broadcast nature of wireless channels and uses relays to improve link reliability. Most of the cooperative communication protocols are assumed to be synchronous in nature, which is not always possible in vehicle-to-vehicle (V2V) communication due to fast moving nature of the nodes. Also the relay nodes are assumed to be half duplex which in turn reduces the spectral efficiency. In this paper, we propose an asynchronous cooperative communication protocol exploiting polarization diversity, which does not require synchronization at the relay node. Dual polarized antennas are employed at the relay node to achieve full duplex amplify-and-forward (ANF) communication. Hence the transmission duration is reduced which results into an increased throughput rate. Capacity analysis of the proposed scheme ascertains the high data rate as compared to conventional ANF. Bit error rate (BER) simulation also shows that the proposed scheme significantly outperforms both the non-cooperative single-input single-output and the conventional ANF schemes. Considering channel path loss, the proposed scheme consumes less total transmission energy as compared to the conventional ANF and non-cooperative scheme. Thus the proposed scheme is suitable for high rate and energy efficient relay-enabled communication. [ABSTRACT FROM AUTHOR]

This paper describes the comparison and parameterization process of dynamic battery models for cell and system simulation. Three commonly used equivalent circuit battery models are parameterized using a numeric optimization method and basic electrical tests with a lithium-ion polymer battery cell. The maximum model performance is investigated, and the parameterized models are compared regarding the parameterization effort and the model accuracy. For the model with the best tradeoff between the parametrization effort and the model accuracy, a reasonable simplification of the parameterization process is presented. This model is parameterized with the simplified parameterization process and, finally, validated by using a current profile obtained from an electric vehicle simulation performing a real-life driving cycle. [ABSTRACT FROM AUTHOR]

This paper presents several of the problems encountered with vector-controlled single-phase induction motor (SPIM), and discusses about the complex implementation of a vector controlled SPIM drive. The vector-controlled symmetrical two-phase induction motor (TPIM) is presented as a viable replacement for the vector-controlled SPIM. The implementation of the proposed vector-controlled TPIM is simple compared to the vector-controlled SPIM. All the TPIM parameters can be calculated simply and precisely. The proposed strategy for TPIM is derived from the indirect vector control strategy used for three-phase ac machines. Several differences between the vector control strategies for the TPIM and for three-phase ac motor are discussed. The validity of the proposed vector-controlled TPIM was verified by simulations and experiments. [ABSTRACT FROM AUTHOR]

To reduce the variance of speckle in coherent imaging systems, one must average images with different speckle realizations. Traditionally, these images have been formed by observing the target region from slightly different angles (spatial compounding) or by varying the involved temporal frequencies (frequency compounding). In this paper, we investigate a third option based on Thomson?s multitaper approach to power spectrum estimation. The tapers are applied spatially, as array weights. Our investigations, based on both recorded ultrasound data and simulations, verify that the multitaper approach can be used for speckle reduction at a rate comparable to that of the more traditional method of spatial compounding. Because of the spectral concentration of the tapers, an added benefit is reduced side lobe levels, which can result in steeper edges and better definition of cyst-like structures. [ABSTRACT FROM PUBLISHER]

This paper studies the effects of natural convection on longitudinal heat transfer and on the air-gap thermal resistance of cables inside conduit installations. Oversimplification of the physical placement of cables inside unfilled conduits is the main shortcoming in currently available thermal models. The study closely investigates the share of each heat-transfer mechanism and the effect of the natural placement of trefoil cables inside the conduit. Measurements from various installation setups are investigated for their impact on heat transfer. The installation-dependent convection correlations adopted in this study have broader applications for the dynamic thermal rating of underground cables inside conduit, troughs, and tunnels. Laboratory measurements are compared with numerical solutions from the IEC 60287 standards, Electra 143 methods, and FEA simulations. [ABSTRACT FROM AUTHOR]

In this paper, three dc/dc ladder multilevel converters are compared. The first one is the classical ladder topology and the two other topologies presented are based on the classical one. A mathematical calculation of the output resistance and the gain of the converter as a function of the number of levels is carried out for the three topologies in order to estimate the voltage drop due to the output current. These calculations are validated with simulations and experimental results. Finally, the behavior of the three topologies is compared through experimental tests. Results show higher performance for the presented converters compared to the classical ladder. [ABSTRACT FROM AUTHOR]

In order to improve the efficiency of wind power generation system (WPGS), many researchers have tried to develop a larger WPGS and a superconducting synchronous generator (SCSG) has been suggested to develop over 5 MW class WPGS. There are two expected types of drive-train, geared and gearless. The structure and electrical parameters of the SCSG depend on the type of drive-train used. This paper deals with a comparative analysis of the 10 MW class geared and gearless types of the SCSG for WPGS. Three drive-trains are designed for the 10 MW class SCSGs using the finite elements method analysis tool. The PSCAD/EMTDC is utilized to simulate electrical and dynamic behaviors of the modeled SCSGs. The simulation results show the operation characteristics of the designed SCSGs and suggest that the single-stage gearbox type drive-train is the most efficient drive-train for the SCSG due to the reduction of the number of rotor poles and the volume of the generator, even though the geared-type drive-train requires periodical maintenance. [ABSTRACT FROM PUBLISHER]

This paper aims at comparing the pseudospectral method and discrete geometric approach for modeling quantization effects in nanoscale devices. To this purpose, we implemented a simulation tool, based on both methods, to solve a self-consistent Schrödinger–Poisson coupled problem for a 2-D electron carrier confinement according to the effective mass approximation model (suitable for FinFETs and nanowire FETs). [ABSTRACT FROM PUBLISHER]

Compared with neutral-point-clamped (NPC) inverters, active NPC (ANPC) inverters enable a substantially increased output power and an improved performance at zero speed for high-power electrical drives. This paper analyzes the operation of three-level (3L) ANPC inverters under device failure conditions, and proposes the fault-tolerant strategies to enable continuous operating of the inverters and drive systems under single and multiple device open- and short-failure conditions. Therefore, the reliability and robustness of the electrical drives are greatly improved. Moreover, the proposed solution adds no additional components to standard 3L-ANPC inverters; thus, the cost for robust operation of drives is lower. Simulation and experiment results are provided for verification. Furthermore, a comprehensive comparison for the reliability function of 3L-ANPC and 3L-NPC inverters is presented. The results show that 3L-ANPC inverters have higher reliability than 3L-NPC inverters when a derating is allowed for the drive system under fault-tolerant operation. If a derated operation is not allowed, the two inverters have similar reliability for device open failure, while 3L-NPC inverters have higher reliability than 3L-ANPC inverters for device short failure. [ABSTRACT FROM AUTHOR]

The matrix converter (MC) is arousing considerable attention as an alternative for conventional ac/ac converters due to the advantages it offers. However, the control and modulation of this converter is complex. This, together with the fact that the MC usually operates at high modulation frequencies, makes the computational load of the platform to be simulated excessively high. All this makes the simulation time of models including the MC excessively long, even more so when both the transient and steady state of the system must be analyzed. This paper presents a new MC simulation technique called Switching State Matrix Averaging (SSMA). Although this is a fixed-step technique, a long simulation step can be used without forfeiting the accuracy of an ideal variable-step simulation. Likewise, the SSMA drastically speeds up the simulation, reducing the amount of required resources and the tuning time of the complex platforms in which the MC is used. A series of simulations has been performed in order to verify the proposed method. Moreover, a comparison between experimental and simulation results has been made, demonstrating the effectiveness of the proposed method. [ABSTRACT FROM AUTHOR]

CMOS technologies can be either dual-well or triple-well. Triple-well technology has several advantages compared to dual-well technology in terms of electrical performance. Differences in the ion-induced single-event response between these two technology options, however, are not well understood. This paper presents a comparative analysis of heavy ion-induced upsets in dual-well and triple-well 40-nm CMOS SRAMs. Primary factors affecting the charge-collection mechanisms for a wide range of particle energies are investigated, showing that triple-well technologies are more vulnerable to low-LET particles, while dual-well technologies are more vulnerable to high-LET particles. For the triple-well technology, charge confinement and multiple-transistor charge collection triggers the “Single Event Upset Reversal” mechanism that reduces sensitivity at higher LETs. [ABSTRACT FROM PUBLISHER]

Design, simulation, fabrication and measurement of two different novel flexible bow-tie antennas, a conventional and a modified bow-tie antenna with reduced metallization, are reported in this paper. The antennas are mounted on a flexible substrate fabricated at the Flexible Display Center (FDC) of Arizona State University (ASU). The substrate is heat stabilized polyethylene naphthalate (PEN) which allows the antennas to be flexible. The antennas are fed by a microstrip-to-coplanar feed network balun. The reduction of the metallization is based on the observation that the majority of the current density is confined towards the edges of the regular bow-tie antenna. Hence, the centers of the triangular parts of the conventional bow-tie antenna are removed without compromising significantly its performance. The return losses and radiation patterns of the antennas are simulated with HFSS and the results are compared with measurements, for bow-tie elements mounted on flat and curved surfaces. The comparisons show that there is an excellent agreement between the simulations and measurements for both cases. Furthermore, the radiation performance of the modified bow-tie antenna is verified, by simulations and measurements, to be very close to the conventional bow-tie. [ABSTRACT FROM AUTHOR]

This paper describes three data driven methods to monitor electromechanical oscillations in interconnected power system operation. The objective is to compare and contrast the performance of the methods. The accuracy of damping ratio and frequency of oscillations are the measures of the performance of the algorithms. The advantages and disadvantages of various techniques and their limitations to measurement noise have been considered while assessing performance. The target frequency and damping are computed using the Nordic power system simulation model. [ABSTRACT FROM PUBLISHER]

In this paper, a new topology of a cascaded multilevel converter is proposed. The proposed topology is based on a cascaded connection of single-phase submultilevel converter units and full-bridge converters. Compared to the conventional multilevel converter, the number of dc voltage sources, switches, installation area, and converter cost is significantly reduced as the number of voltage steps increases. In order to calculate the magnitudes of the required dc voltage sources, three methods are proposed. Then, the structure of the proposed topology is optimized in order to utilize a minimum number of switches and dc voltage sources, and produce a high number of output voltage steps. The operation and performance of the proposed multilevel converter is verified by simulation results and compared with experimental results of a single-phase 49-level converter, too. [ABSTRACT FROM AUTHOR]

In this paper, printing characteristics for the bit printing and the edge printing were compared by micromagnetic simulation. As a result, servo signal can be clearly recorded using both printing methods, and printing field dependence of printing performance for each method is considerably different. The transition of bit-printed magnetization is almost straight for any pattern, while that of edge-printed magnetization has several ridges. On the other hand, the edge printing is robust for the change in the printing field, compared with the bit printing. [ABSTRACT FROM AUTHOR]

The growing importance of signal integrity (SI) analysis in integrated circuits (ICs), revealed by modern system-in-package methods, is demanding for new models for the IC sub-systems which are both accurate, efficient and extractable by simple measurement procedures. This paper presents the contribution for the establishment of an integrated IC modeling approach whose performance is assessed by direct comparison with the signals measured in laboratory of two distinct memory IC devices. Based on the identification of the main blocks of a typical IC device, the modeling approach consists of a network of system-level sub-models, some of which with already demonstrated accuracy, which simulated the IC interfacing behavior. Emphasis is given to the procedures that were developed to validate by means of laboratory measurements (and not by comparison with circuit-level simulations) the model performance, which is a novel and important aspect that should be considered in the design of IC models that are useful for SI analysis. [ABSTRACT FROM PUBLISHER]

As the output power of photovoltaic (PV) array changes with the change of external environment and load, the maximum power point tracking (MPPT) technology is needed to bring the efficiency of PV device into full play. In this paper, the chaos search theory is first applied on the MPPT technology of PV system; the chaos search algorithm based on dual carrier increases the adequacy of chaos search and overcomes the blindness of traditional chaos search, thus improves the search efficiency and solves the problem of multiple MPP under partially shadowing conditions. Comparative tests show that the proposed method can track the step response quickly and accurately; at the same time get better optimization result. Simulation and experimental results showed the effectiveness and good performance of the proposed method. [ABSTRACT FROM AUTHOR]

This paper compares four different methods for determining the electrical damping of a power system seen from one generator as a function of frequency. This information is useful when the risk for subsynchronous resonance (SSR) in the system is evaluated. The study compares one frequency scanning method which is implemented in a time-domain digital simulation program with three methods of different complexity based on analytical calculations. The time-domain simulation method is easily implemented with a detailed model of the power system including complex load and generator models, whereas the analytical methods are based on simpler models of the power system. The computational effort is much larger for the time-domain method than for the analytical methods. In the study, all methods were used to determine the damping characteristics of a four-machine power system in different configurations. The study shows that fast analytical methods may provide results which closely agree with the detailed method of time-domain simulation. However, the study also shows that the level of accuracy in the analytical model is very important. [ABSTRACT FROM AUTHOR]

This paper compares several medium-voltage power conversion systems for plasma torch application. The thermal plasma torch rated for 3 MW, 2 kA with the physical size of 1 m long is selected. The dynamic characteristics of the dc arc in a plasma torch are investigated using advanced 3-D magnetohydrodynamics simulation. The arc voltage noise of ±10% due to the periodic pressure wave is modeled as a sawtooth waveform in arc power loss term. The parameters of the Cassie-Mayr arc model are calculated based on 3-D simulation. A 12-pulse thyristor rectifier and two-phase staggered three-level step-down dc-dc converter having 12-pulse front-end diode rectifier are compared under the same dynamic operating condition. The three-level dc-dc converter has superior dynamic performance over the 12-pulse thyristor rectifier under the existence of arc disturbance noise. This power converter topology provides higher ignition voltage around 5 kV during ignition phase and higher arc stability. [ABSTRACT FROM AUTHOR]

This paper presents a driving simulation whose aim is twofold: 1) to investigate the possibility of reducing motion clearance to achieve compact and low-cost driving simulators and 2) to evaluate multimodal and immersive virtual reality motion restitution in platooning driving. The choice has been made for a driving simulator having at least two degrees of freedom (DOF). These consist of the longitudinal displacement and seat rotations. The simulator is also equipped with a force feedback steering wheel for virtual drive assistance. These components are gathered on a serial kinematics-type platform to facilitate a control scheme and avoid the architecture complexity. A comparative study was made to devise a motion cueing strategy, taking into account both the psychophysical and technological constraints. Experimentations were carried out for several case combinations of the longitudinal displacement and seat rotations. [ABSTRACT FROM AUTHOR]

A new algorithm, the "shifted Rayleigh filter," is introduced for two- or three-dimensional bearings-only tracking problems. In common with other "moment matching" tracking algorithms such as the extended Kalman filter and its modern refinements, it approximates the prior conditional density of the target state by a normal density; the novel feature is that an exact calculation is then performed to update the conditional density in the light of the new measurement. The paper provides the theoretical justification of the algorithm. It also reports on simulations involving variants on two scenarios, which have been the basis of earlier comparative studies. The first is a "benign" scenario where the measurements are comparatively rich in range-related information; here the shifted Rayleigh filter is competitive with standard algorithms. The second is a more "extreme" scenario, involving multiple sensor platforms, high-dimensional models and noisy measurements; here the performance of the shifted Rayleigh filter matches the performance of a high-order bootstrap particle filter, while reducing the computational overhead by an order of magnitude. [ABSTRACT FROM AUTHOR]

Several new "sum-of-sinusoids" models have recently been introduced for the simulation of Rayleigh fading channels. These models are statistical in nature implying that their simulation parameters such as the Doppler frequencies are random. They have been shown to accurately reproduce some of the desired statistical properties of the faded envelope such as the time autocorrelation and the level crossing rate. However, a comparative analysis of these models, hitherto scattered throughout the literature, is not available. This paper compares these models in terms of their complexity and performance. The performance assessment is based upon the variance of the time average statistical properties from their ideal ensemble averages. [ABSTRACT FROM AUTHOR]

RFID tag identification is a crucial problem in UHF RFID systems. Traditional tag identification algorithms can be classified into two categories, ALOHA-based and tree-based. Both of them are inefficient due to the incidental high coordination cost. In this paper, we bring CSMA into UHF RFID systems to enhance tag read rate by reducing coordination cost. However, it is not straightforward due to the simple hardware design of passive RFID tags, which is unable to sense the transmissions or collisions of other tags. To tackle this challenge, we propose receiver-based CSMA (RCSMA) in this paper. In RCSMA, the reader notifies the tags channel condition. According to different sensing results of reader's notifications, the tags take corresponding actions, e.g., random back off. RCSMA does not require special RFID tag hardware design. An absorbing Markov chain model is presented to analyze the performance of RCSMA and shown to be consistent with the simulation results. Compared with optimized ALOHA-based algorithms and optimized tree-based algorithms, RCSMA can enhance the tag read rate by 30-70 percent under different reader and tag data rates. [ABSTRACT FROM AUTHOR]

This paper describes a greatly simplified model for the prediction of phase noise in oscillators which use a negative resistance as the active element. It is based on a simple circuit consisting of the parallel addition of a noise current, a negative admittance/resistance, and a parallel (Qlimited) resonant circuit. The transfer function is calculated as a forward trans-resistance (VOUT/IIN) and then converted to power. The effect of limiting is incorporated by assuming that the phase noise element of the noise floor is kT/2, i.e., -177 dBm/Hz at room temperature. The result is the same as more complex analyses, but enables a simple, clear insight into the operation of oscillators. The phase noise for a given power in the resonator appears to be lower than in feedback oscillators. The reasons for this are explained. Simulation and experimental results are included. [ABSTRACT FROM PUBLISHER]

A method to detect partial discharge (PD) is considered effective for gas insulated switchgear (GIS) insulation diagnostics. In this paper, for a 154 kV model GIS, the influence of the enclosure diameter on PD propagation characteristics was initially investigated using model GIS by varying the enclosure size. Secondly, an experiment was conducted for metallic particles placed in different locations as a source of PD (particle adhering to the center conductor or free metallic particle). Thirdly, an actual PD experiment was conducted in an Lshaped form to study the influence of GIS shape on PD-radiated electromagnetic (EM) waves. In addition, in order to study the experimental results in detail, a simulation using the FD-TD method was conducted for comparison with these experimental results. Following the experiment, the larger the enclosure diameter, the greater the measured amplitude of PD having occurred around the center conductor. In addition, it emerged that, where the particle was close to the center conductor, EM waves propagating due to PD were less likely to be damped compared with the case where particles were placed on the bottom of the enclosure. Furthermore, following the investigation of the propagation characteristics in the L-shaped form, it emerged that, while a high frequency component of frequency exceeding that of the TEM wave component was reflected at the L-shaped part, the TEM wave component passed through almost unaffected by the latter. The propagation of the TEM mode component could be also found via FD-TD analysis. [ABSTRACT FROM AUTHOR]

The paper addresses the problem of adaptive manoeuvring targets tracking in clutter with a phased array radar. The tracking algorithm is based on the combination of the interacting multiple models (IMM) algorithm and the joint probabilistic data association filter (JPDAF), the resulting algorithm is named IMMJPDAF algorithm. Moreover, the phased array radar is a multifunction radar with the capability to select adaptively the sampling time interval; consequently, the tracking performance is improved. First, a complete comparative study between the IMMJPDAF algorithm and the multirate IMMJPDAF (MRIMMJPDAF) algorithm for tracking close manoeuvring targets with varying amounts of clutter density is presented. Then a description is made of the integration of a new fast method into the IMMJPDAF algorithm to adaptively select the next update time according to the targets motions. We call the resulting algorithm, the fast adaptive IMMJPDAF (FAIMMJPDAF) algorithm. Furthermore, an enhancement of the tracking accuracy in the FAIMMJPDAF algorithm is made by also taking into account the separation distance between targets in the selection of the next update time. The performance of the proposed algorithm, named improved fast adaptive IMMJPDAF (IFAIMMJPDAF) algorithm is assessed via Monte Carlo Simulations and compared with that of four algorithms that use an adaptive selection of the update time: FAIMMJPDAF algorithm, the adaptive IMMJPDAF that uses a modified version of the van Keuk criterion (MAIMMJPDAF), the adaptive IMMJPDAF that uses the original van Keuk method (AIMMJPDAF), and the IMMJPDAF (CIMMJPDAF) that uses a constant update time. [ABSTRACT FROM AUTHOR]

In this paper, a detailed description and comparison of speckle reduction of medical ultrasound, and in particular echocardiography, is presented. Fifteen speckle reduction filters are described in a detailed fashion to facilitate implementation for research and evaluation. The filtering techniques considered include anisotropic diffusion, wavelet denoising, and local statistics. Common nomenclature and notation are adopted, to expedite comparison between approaches. Comparison of the filters is based on their application to simulated images, clinical videos, and a computational requirement analysis. The ultrasound simulation method provides a realistic model of the image acquisition process, and permits the use of a noise-free reference image for comparison. Application of objective quality metrics quantifies the preservation of image edges, overall image distortion, and improvement in image contrast. The computational analysis quantifies the number of operations required for each speckle reduction method. A speed-accuracy analysis of discretization methods for anisotropic diffusion is included. It is concluded that the optimal method is the OSRAD diffusion filter. This method is capable of strong speckle suppression, increasing the average SNRA of the simulated images by a factor of two. This method also shows favorable edge preservation and contrast improvement, and may be efficiently implemented. [ABSTRACT FROM AUTHOR]