System Simulation

In this paper a new intelligent identification method of uncertainty bound utilizes an adaptive neurofuzzy inference system (ANFIS) in a feedback scheme is proposed. The proposed ANFIS feedback structure performs better in determining the uncertainty bounds with minimum number of iterations and error. In our proposed technique, the intelligent identified uncertainty weighting function is validated utilizing v-gap to ensure the stability of the designed H controlled system. Our proposed intelligent identification of uncertainty bound is demonstrated on a servo motion system. Simulation and experimental results show that the new ANFIS identifier is more reliable and highly efficient in estimating the best uncertainty weighting function for robust controller design.

The design of #exible manufacturing systems (FMSs) is an essential but costly process. Although FMS design appears to be an excellent area for applying arti"cial intelligence (AI) and computer simulation techniques, to date there have been limited investigations on integrating AI with the modular simulation software available for FMS design. In this paper an integrated approach for the automatic design of FMS is reported, which uses simulation and multi-criteria decision-making techniques. The design process consists of the construction and testing of alternative designs using simulation methods. The selection of the most suitable design (based on the multi-criteria decision-making technique, the analytic hierarchy process (AHP)) is employed to analyze the output from the FMS simulation models. Intelligent tools (such as expert systems, fuzzy systems and neural networks), are developed for supporting the FMS design process. Active X technique is used for the actual integration of the FMS automatic design process and the intelligent decision support process.

In this paper a reactive local navigation system is presented, for an autonomous non-holonomic mobile robot navigating in dynamic environments. The reactive navigation system integrates an obstacle detection method [4] and a new reactive collision avoidance method. The sensory perception is based in a laser range finder (LRF) system. Simulation results are presented to verify the effectiveness of the proposed local navigation system in unknown environments with multiple moving objects. The comparison of results are shown, between two different approaches, a Velocity Obstacle (VO) approach and our own, based in the Dynamic Window (DW) concept.

The test environments for system level evaluations of IMT-A (International Mobile Telecommunications-Advanced) candidate technologies are analyzed. Compared to the evaluation criteria for previous IMT standards, the IMT-A test environments provide significantly more realistic settings for evaluating system-level performance. The models include line-ofsight probability in all scenarios, different groups of users in terms of propagation and speed, as well as indoor and outdoor deployments. This contribution scrutinizes the evaluation conditions and presents resulting performance for a basic Long-Term Evolution (LTE) candidate system. Each environment contains challenging characteristics. Examples include a mix of indoor and outdoor users, a mix of line-of-sight and non-line-ofsight conditions, and terminal speeds making accurate tracking of channel quality difficult. Together, these characteristics suggest that a radio transmission technology fulfilling the ITU IMT-A requirements is well suited for meeting a variety of challenges of real deployment scenarios.

The solidification behavior of liquid metal in a container under rapid cooling process is one of the major concerns to be analyzed. In order to analyze its fundamental behavior, a three- dimensional (3D) fluid dynamics simulation was developed using a particle-based method, known as the smoothed particle hydrodynamics (SPH) method. Governing equations that determine the fluid motion and heat transfer involving phase change process are solved by discretizing their gradient and Laplacian term with the moving particles and calculating the interaction with its neighboring particles. The results demonstrate that the SPH mehod can successfully reproduce the behavior and defect prediction of liquid metal solidification process.

The Human System Simulation Laboratory (HSSL) at the Idaho National Laboratory is one of few facilities of its kind that allows human factors researchers to evaluate various aspects of human performance and human system interaction for proposed reactor designs and upgrades. A basic system architecture, physical configuration and simulation capability were established to enable human factors researchers to support multiple, simultaneous simulations and also different power plant technologies. Although still evolving in terms of its technical and functional architecture, the HSSL is already proving its worth in supporting current and future nuclear industry needs for light water reactor sustainability and small modular reactors. The evolution of the HSSL is focused on continual physical and functional refinement to make it a fully equipped, reconfigurable facility where advanced research, testing and validation studies can be conducted on a wider range of reactor technologies. This requires the implementation of additional plant models to produce empirical research data on human performance with emerging human-system interaction technologies. Additional beneficiaries of this information include system designers and HRA practitioners. To ensure that results of control room crew studies will be generalizable to the existing and evolving fleet of US reactors, future expansion of the HSSL may also include other SMR plant models, plant-specific simulators and a generic plant model aligned to the current generation of pressurized water reactors (PWRs) and future advanced reactor designs. Collaboration with industry partners is also proving to be a vital component of the facility as this helps to establish a formal basis for current and future human performance experiments to support nuclear industry objectives. A long-range Program Plan has been developed for the HSSL to ensure that the facility will support not only the Department of Energy's Light Water Reactor Sustainability Program, but also to provide human factors guidance for all future developments of the nuclear industry.

Compact silicon carbide (SiC) power semiconductor device models for circuit simulation have been developed for power Schottky, merged-PiN-Schottky, PiN diodes, and MOSFETs. In these models, the static and dynamic performance of the power SiC devices requires specific attention to the low-doped, voltage blocking drift region; the channel transconductance in MOS devices; the relatively low-intrinsic carrier concentration; the incomplete ionization of dopants; and the temperature dependent material properties. The modeling techniques required to account for each of these characteristics are described.

GATE (Geant4 Application for Tomographic Emission) simulation toolkit has become a well validated toolkit for the simulation of SPECT and PET systems. A very important feature of GATE is that it allows modelling of time-dependent phenomena. In addition, complex voxelized object such as realistic anthropomorphic or small animal phantoms can be used as emission sources. In this work two small field of view scanners have been evaluated experimentally, modelled in GATE and mice studies have been simulated using MOBY mouse phantom. Two scanners have been simulated: The first one is a mouse sized gamma camera (field of view is 5x10cm) that is based on two Hamamatsu H8500 PSPMTs, a NaI pixelized scintillator and a tungsten collimator with hexagonal parallel holes. The system has been modelled in GATE and good agreement has been found between simulation and experimental results. MOBY mouse has been introduced as a voxelized source and planar and tomography simulations were carried out. The second small animal PET scanner has four heads which are equipped with a H8500 PSPMTs and a pixelated LYSO scintillator. System's geometry has been modelled in GATE. The results of both systems simulation and comparison between simulation and experimental data are presented. In addition, mouse bone scans were simulated both for SPECT and PET and tomographic image are derived. The presented methodology is aimed to provide all necessary tools in order to perform optimized simulations of small animal emission tomography scans..

The Greater sage-grouse (Centrocercus urophasianus) occupies the sage brush habitats of Western North America. Large population declines in the last several decades have made it a candidate for possible listing under the Endangered Species Act. Listing was recently avoided in part because local working groups are developing long-range management plans in conjunction with federal and local agencies. The Foster Creek Conservation District, a working group in Douglas County, Washington, saw the potential for system dynamics to synthesize known sage-grouse dynamics and local land use patterns to support development of their Habitat Conservation Plan and subsequent land management decisions. This case study highlights the integration of science, local knowledge and social concerns into a participatory process that uses system dynamics as a forum for the exploration of the impacts of land management decisions upon the sage-grouse population and the landowners of Douglas County, Washington.

This paper is devoted both to the study of observability criteria and the design of observers in the continuous Petri net setting. The concept of structural observability, regarding the possibility of estimating the marking of places, i.e., the system state, for any speed of the transitions is introduced and studied for the subclass of join-free Petri nets (JF). For non-join-free Petri nets, conditions to compute suitable state estimates are established. The proposed observers are piecewise linear systems that assure the continuity of the estimate even when a switch occurs. The system simulation may allow us to estimate even the unobservable space of the net system during a given time period.

Modelling and simulation of PEM fuel cell stack operation is developed in Simulink Ò environment and validated through experimental data. The present work is the starting point for the development of a user friendly and versatile tool aimed at controlling and optimizing the operation of a PEMFC stack; in addition, it could be of help in stack and BOP components design, for instance feeding and humidification systems, cooling circuit, temperature control logic and electrical interface. The constitutive equations used to model the FC stack operation are the fundamental equations of electrochemistry. First, the model is used to describe the behaviour of a single cell under steady-state conditions upon varying variables such as temperature, pressure and relative humidity of reactants; then, it is applied to simulate the operation of a stack configuration, including also fluid-dynamics aspects, thermal and kinetic behaviour of feed systems. In particular, thermal control modelling is based on a simplified approach where different heat removal mechanisms are accounted for in a separate way. In its present state, the simulation tool so developed allows a feasible investigation of some process variables influence on the FC stack performances. The stack modelling is tested against benchmark results obtained from a 300W 20-cell air-cooled stack under variable operative conditions. MEAs based on Nafion 112 and Carbon cloth GDLs developed ad hoc are assembled into each cell of the stack. Although the model is quite simple, these preliminary results point out that it may be an adequate tool to set design targets and support further steps of optimization.

An advanced vehicle simulator model called ADVISOR has been developed at the National Renewable Energy Laboratory to allow system-level analysis and trade-off studies of advanced vehicles. Because of ADVISOR's fast execution speed and the open programming environment of MATLAB/Simulink, the simulator is ideally suited for doing parametric studies to map out the design space of potential high fuel economy vehicles (3X) consistent with the goals of the Partnership for New Generation of Vehicles (PNGV). Five separate vehicle configurations have been modeled including 3 lightweight vehicles (parallel, series, and conventional drivetrains) along with 2 vehicles with 1996 vehicle weights (parallel and conventional drivetrains). The sensitivity of each vehicle's fuel economy to critical vehicle parameters is then examined and regions of interest for the vehicles mapped out through parametric studies. Using the simulation results for these vehicles, the effect of hybridization is isolated and analyzed and the trade-offs between series and parallel designs are illustrated.

Article CITATION 1 READS 78 4 authors, including: Some of the authors of this publication are also working on these related projects: Optoelectronic Properties of Nanofibres Zn-doped and Zr-doped Perovskite-type as Transparent and Conductive Oxide Films View project Photovoltaic Solar Thermal Technology (PV/T) View project Salwan S. Dihrab

In the last ten years, there has been much research on active noise control (ANC) systems and transaural sound reproduction (TSR) systems. In those fields, multichannel FIR adaptive filters are extensively used. For the learning of FIR adaptive filters, recursive-least-squares (RLS) algorithms are known to produce a faster convergence speed than stochastic gradient descent techniques, such as the basic least-mean-squares (LMS) algorithm or even the fast convergence Newton-LMS, the gradient-adaptive-lattice (GAL) LMS and the discrete-cosine-transform (DCT) LMS algorithms. In this paper, multichannel RLS algorithms and multichannel fast-transversal-filter (FTF) algorithms are introduced, with the structures of some stochastic gradient descent algorithms used in ANC: the filtered-x LMS, the modified filtered-x LMS and the adjoint-LMS. The new algorithms can be used in ANC systems or for the deconvolution of sounds in TSR systems. Simulation results comparing the convergence speed, the numerical stability and the performance using noisy plant models for the different multichannel algorithms will be presented, showing the large gain of convergence speed that can be achieved by using some of the introduced algorithms.

SimCity is a system simulation game frequently used in educational settings. This study investigates whether playing SimCity could change Turkish adolescents' perception of the city they live in. We hypothesized that playing the game would lead to perceptional changes in the players regarding their ideal and real cities. Two hundred forty eight 13year old Turkish adolescents attending 7th grade constituted the sample. Ninety adolescents played the game for six weeks. Their scores on various perception variables on city issues were compared to those of the control group's. Results showed that students in the experimental group changed their expectations of an ideal city to resemble the game, expected city authorities to pay greater attention to city issues, and reported higher level of distrust to city authorities at the post-test compared to those in the control group. Findings are discussed in terms of the potential of SimCity in training informed citizens. Ó

A fuel cell clearly is a multidisciplinary system. The authors have chosen an original energy approach that they have applied via the Bond Graph formalism. A PEM fuel cell Bond Graph model is proposed and detailed. Its potentialities are then illustrated by studies on the fuel cell dynamic behavior (current harmonic effects, etc.) and system simulations (electricity generating unit based on a PEM fuel cell, etc.).

In this paper, a finite-difference time-domain (FDTD) analysis of the transmission line equations for a general circuit simulator is presented. A two-port circuit representation is derived for integrating a dispersive transmission line network within a circuit/system simulator. The circuit model consists of resistive elements and dependent current sources, which are updated at every time step by the FDTD algorithm. The frequency dependence of the conductors' parameters is taken care of by a recursive integration that employs the Vector Fitting algorithm. The application of this model is presented for several examples, such as nonuniform transmission lines, plane wave excitation of the line, and determination of overvoltages induced by a nearby lightning stroke.

Finding the longest simple path in a generic undirected graph is a challenging issue that belongs to the NP-Complete class of problems. Four approaches based on genetic algorithms to solve this question are presented in this report. The first three algorithms proposed use crossover mechanisms between pairs of solutions based on their intersecting regions and the fourth one uses a mutation mechanism on individual solutions, in which the perturbation applied depends on the state of the system. Simulation results validate the distinct approaches, reveal their good performance and provide hints for their application in robotics, package networks and other fields.

This work addresses the attitude control of a satellite by applying MIMO quantitative feedback approach. The objective is to design a set of proper controllers in presence of unknown disturbances and parametric uncertainties for a nonlinear MIMO system. The physical model of satellite utilizes three reaction wheels as actuators. The controller goal is to change the rotational speed of reaction wheels to adjust the satellite in desired course. First, the mathematical model of satellite and its actuators using angular kinematics and kinetic equations is developed. Quantitative feedback theory is then applied to synthesize a set of linear controllers that deals with both nonlinearities in the equations and unknown parameters or disturbance sources. By using basically non-interacting desired outputs and extracting sets of linear time invariant equivalent (LTIE) plants, the controllers set is designed for nine SISO systems. Simulation of closed loop system shows that all desired specifications of closed loop (tracking, stability, disturbance rejection) are robustly satisfied.

As the number of processing nodes on chip multi-processors (CMPs) keeps increasing, providing efficient communication with the on-chip interconnect becomes increasingly critical. With 32core CMP designs on the drawing table of engineers, there is a demand for accurate simulation models that capture all the complexities and interactions of the different design layers including the application, operating system, cache hierarchy, coherency protocol, and other on-chip resources. These components cannot be modeled anymore in isolation as unpredicted performance anomalies may arise once all the system variables are taken into account.

This work includes the evaluation of the solar contribution in solar cooling systems by the newly developed solar cooling design chart. The effect of collector area and storage volume on the solar fraction is well taken into account in the cooling design charts. The results of several experimental installations are compared with the present cooling f-chart predictions. The agreement is very good, which verifies the validity of design predictions by the new cooling f-chart. Changing the collector area in a solar cooling system has a similar effect on the solar fraction as that in a solar heating system. Storage volume appears to show an optimum in a solar cooling system with a marked influence on the solar contribution. The cooling f-chart may be used in equation form for design purposes. Design by solar cooling design charts is applicable for different building constructions, solar collector types, length of cooling season, location and meteorological conditions.

Increasing attention is being paid to the application of uncertainty and sensitivity analysis methods to model validation and building simulation. The idea is to let users to apply uncertainty bands to their model input data. These bands are then propagated through the model to determine the uncertainty bands of the simulation results. Mathematical methods to deal with uncertainties in computer simulations are well developed. One of the main difficulties the practitioner finds when trying to apply these techniques to building simulation is the lack of information on the uncertainty that affects to typical input variables (thermophysical properties of materials, internal gains, infiltration, etc.). This paper is a contribution to fill this gap. We present polynomial fits for the average thermal conductivity and its standard deviation as functions of density for typical insulation materials. These functions were obtained by processing a large experimental data set, which was compiled in a previous European project headed by the BRE Scottish Laboratory. To illustrate how these results can be used in practice, an example is discussed on the validation of the mathematical model of a solar thermal collector.

In this paper a complete communication system simulation package is described, which includes digital as well as analog operations to be performed on the signal to be transmitted. The package simulates the transmitter, the communication channel, and the receiver.

This work presents the development, validation and use of a SIMULINK integrated vehicle system simulation composed of engine, driveline and vehicle dynamics modules. The engine model links the appropriate number of single-cylinder modules, featuring thermodynamic models of the in-cylinder processes with transient capabilities to ensure high fidelity predictions. A detailed fuel injection control module is also included. The engine is coupled to the driveline, which consists of the torque converter, transmission, differential and prop shaft and drive shafts. An enhanced version of the point mass model is used to account for vehicle dynamics in the longitudinal and heave directions. A vehicle speed controller replaces the operator and allows the feedforward simulation to follow a prescribed vehicle speed schedule. For the particular case reported here, the simulation is configured for the International 4700 series, Class VI, 4x2 delivery truck powered by a V8 turbocharged, intercooled diesel engine. The integrated vehicle simulation is validated against transient data measured on the proving ground. Comparisons of predicted and measured responses of engine and vehicle variables during vehicle acceleration from 0 to 60 mph and from 30 to 50 mph show very good agreement. The simulation is also used to study trade-offs involved in redesigning control strategies for improved performance of the vehicle system.

This work presents a top-down design methodology for a behavioral modeling System, based on smart sensors for aerospace structures monitoring, implemented on a MATLAB/Simulink environment. The modeled acquisition platform in this aeronautic health monitoring systems (AHMS) is built using the following specific sensors: humidity, pressure, temperature, stress and acceleration. For this application it has been implemented frequency acquisition techniques ensuring

Research on more productive and sustainable sugarcane production systems would be aided by a comprehensive simulator of the sugarcane crop that is cognisant of a broader crop-soil-management system. A sugarcane crop model is described that can be deployed in the APSIM framework for agricultural systems simulation. The model operates on a daily time step, grows a leaf canopy, uses intercepted radiation to produce assimilate, and partitions this assimilate into leaf, structural stalk and sugar. The crop physiological processes represented in the model respond to the radiation and temperature environment and are sensitive to water and nitrogen supply. The model simulates growth, water use, N accumulation, sugar dry weight and fresh cane yield for plant and ratoon crops in response to climate, soil, management and genotypic factors. The model was developed on 35 datasets from Australia, Hawaii, South Africa and Swaziland, covering a wide range of crop classes, latitudes, water regimes and nitrogen supply conditions. Coefficients of determination for model predictions compared to observed data included 0.79 for LAI, 0.93 for crop biomass, 0.83 for stalk sucrose and 0.86 for N accumulation in above ground tissues. The particular strengths of this model are discussed in the context of agricultural systems simulation.

An integrated transient simulation program is developed for simulating the Iraqi solar house cooling system, using TRNSYS as a design tool. The simulation is modeled for other virtual solar cooling systems similar to the Iraqi solar house. A number of computer programs were developed and used in parallel with TRNSYS for developing an integrated program for the complete simulation of a solar cooling system with a lithium bromide-water absorption chiller. The results obtained from the simulation were used to develop a general design procedure for solar cooling systems, presented in a graphical form called the cooling f-chart. Using this design chart simplifies the designerÕs task for predicting the long term cooling energy supplied from a solar collector array serving an absorption chilled water system. A correlation was developed from the simulation results for estimating the hot water storage size necessary for the solar cooling system. This was based on minimizing the energy discarded from the vent valve when the solar heated water attains a temperature higher than the boiling temperature.

Systems which assess the comparative environmental impact of pesticides may enable farmers and policy makers to choose effective practices for pest control with the least detrimental impact. This paper reviews a number of approaches that have been proposed by research, planning and regulatory agencies for assessing pesticide impacts. Major issues and challenges in developing assessment models include how to incorporate and synthesize a broad range of environmental parameters in creating an integrated assessment; how to evaluate, integrate and present economic and environmental information within one assessment framework; and how to strike a balance between the advantages of the ease of use of simpler systems with the information-richness of more complex systems that may be prohibitively difficult to use. We conclude that universal answers to these questions are not possible because of different specific objectives, methods and decision-making contexts of particular assessment systems.

Cheese analogues are usually defined as products made by blending individual constituents, including non-dairy fats or proteins, to produce a cheese-like product to meet specific requirements. They are being used increasingly due to their cost-effectiveness, attributable to the simplicity of their manufacture and the replacement of selected milk ingredients by cheaper vegetable products. Sales of cheese analogues are closely linked to developments in the convenience food sector, where they extend the supply and lower the cost. Moreover, there is an ever-increasing interest among consumers in food products which contain less total fat, saturated fat, cholesterol, and calories. Development of cheese analogues involves the use of fat and/or protein sources other than those native to milk, together with a flavour system simulating as closely as possible that of the natural product. It is also necessary to develop a suitable processing regime capable of combining these elements to provide the required textural and functional properties. Cheese analogues may be regarded as engineered products. Cheese analogues represent little threat to the continued consumption of natural cheeses: Their major role at present is undoubtedly in the cost-cutting exercises of pizza manufacturers. The dairy industry has to take the view that imitation products are the result of developments in product technology and market demand. Thus not to get involved would mean curtailment of product innovation and market opportunities.

Shipping contributes 4.5% to global CO 2 emissions and is not covered by the Kyoto Agreement. One method of reducing CO 2 emissions on land is combined cooling heating and power (CCHP) or trigeneration, with typical combined thermal efficiencies of over 80%. Large luxury yachts are seen as an ideal entry point to the off-shore market for this developing technology considering its current high cost.

A dynamic model of a centrifugal compressor capable of system simulation in the virtual test bed (VTB) computational environment is presented. The model is based on first principles, i.e. the dynamic performance including the losses is determined from the compressor geometry and not from the experimentally determined characteristic performance curves. In this study, the compressor losses, such as incidence and friction losses, etc., are mathematically modeled for developing compressor characteristics. For easy implementation in the VTB platform, the non-linear governing equations are discretized in resistive companion (RC) form. The developed simulation model can be applied to virtually any centrifugal compressor. By interfacing with a composite system, such as a Brayton cycle gas turbine, or a fuel cell, the compressor dynamic performance can be evaluated. The surge line for the compressor can also be determined from the simulation results. Furthermore, the model presented here provides a valuable tool for evaluating the system performance as a function of various operating parameters.

This paper examines the interrelationships between public transport and road pricing at both theoretical and empirical grounds. First, the main decision parameters of the interplay between road pricing and public transport are reviewed and appropriate methodological approaches are identified. A set of policies which aim at improving urban public transport ridership and reducing private vehicle use, are considered on the basis of a flexible consumer demand system and evaluated through simulation experiments. The experiments focus on the hypothetical implementation of a national distance-based road charging policy package in Greece. The simulation results indicate that a suitably designed policy package can significantly enhance modal split in favor of public transport without significantly increasing the level of road user charges. To be more specific, for a nation-wide scheme, a combination of an optimal vehicle-km charge (in terms of the optimal fuel price index share required to achieve the desired urban public transport expenditure share) with a half-fare policy results in a considerable reduction of the private vehicle expenditure share, but with a much lower level of road user charge. For the highly urbanized region of Attica, the imposition of the optimal vehicle-km charge per se (without affecting urban transit fares) can provide the largest benefits, in terms of considerably reducing private vehicle share and attaining the target level of urban public transport share.

A lithium-ion battery employing a novel phase change material (PCM) thermal management system was designed for an electric scooter. Passive thermal management systems using PCM can control the temperature excursions and maintain temperature uniformity in Li-ion batteries without the use of active cooling components such as a fan, a blower or a pump found in air/liquid-cooling systems. Hence, the advantages of a compact, lightweight, and energy efficient system can be achieved with this novel form of thermal management system. Simulation results are shown for a Li-ion battery sub-module consisting of nine 18650 Li-ion cells surrounded by PCM with a melting point between 41 and 44 • C. The use of aluminum foam within the PCM and fins attached to the battery module were studied to overcome the low thermal conductivity of the PCM and the low natural convection heat transfer coefficient. The comparative results of the PCM performance in the presence of Al-foam and Al-fins are shown. The battery module is also simulated for summer and winter conditions. The effect of air-cooling on the Li-ion battery was also studied. These simulation results demonstrate the successful use of the PCM as a potential candidate for thermal management solution in electric scooter applications and therefore for other electric vehicle applications.

Multi-Input Multi-Output (MIMO) has emerged as a hot topic in wireless communications during the last decade. This is due to possible dramatic increases in reliability and capacity as compared to single-antenna solutions. However, much of the existing theoretical results are based on very simplistic models of the antennas and transciever circuitry. Within the Strategic Research Center on Atenna Systems Charmant at Chalmers, we are developing a systems simulator for making more realistic studies of MIMO systems. Models of different complexity can be used for the different components. For the linear components, S-parameters are used as the interface. These can come from theoretical models, electromagnetic field simulations, or directly from measurements. For the non-linear components, simple memoryless models can be used, as existing in the RF Toolbox. However, wideband applications demand more elaborate models. We have implemented a so-called memory polynomial model, which has been found to match measurements of nonlinear wideband power amplifiers well. Since RF Toolbox cannot handle multi-port scattering matrices (yet), the MIMO part is here computed in a Matlab function, and then implemented as a MIMO transfer function. The paper describes an implementation of a transciever chain including mixers, filters, PA/LNA, matching network, MIMO antennas and channel models. The simulator can be used for a wide range of wireless communication applications.

In this paper the implementation of a low complexity Rake Receiver (RR) and Channel Estimator (CE) for Direct Sequence Spread Spectrum (DSSS) systems is presented with main scope to provide adaptability in receiver parameters while keeping the complexity at low levels. The trend in communication systems is towards dynamically adjusting system implementations that can adapt their structure to the continuously changing transmission characteristics. Following this trend we propose an architecture that is based on the spreading factor of the system, which controls the number of the taps that the CE and the RR will use depending on the current channel conditions. Moreover, based on a resource sharing approach of the main system components, that yet meets the standard bit rates, low complexity is achieved avoiding otherwise necessary complex structures such as complex multipliers. Furthermore we implement the proposed system on FPGA that gives us the ability to measure performance in terms of Bit Error Rate (BER) in addition to that of power dissipation and area. Thus the performance of the system is compared with the performance of a high level system simulation of the same system, accomplishing the same BER levels. Finally the system implemented on a Xilinx Spartan-3 MB board occupies 56% of the total slices and consumes 103.45mW with a 5V supply.

« La décennie comprise entre 1910 et 1920 fut l'âge des ténèbres de la musique moderne américaine. Les rares lueurs d'activité étaient aussitôt éclipsées par une obsession quasi absolue envers le répertoire historique européen. » 7 C'est dans ce climat peu propice à la créativité que le pianiste Leo Ornstein (1893-2002) se démarque de la scène musicale new-yorkaise. Il interprète, lors d'une série de récitals, parmi des oeuvres de compositeurs européens tels que Schoenberg, Scriabine et Ravel, ses propres compositions. Les oeuvres de Ornstein, comme Wild Men's Dance, Impression of Notre-Dame, Dwarf Suite et A la Chinoise, partagent certains traits : titres à programme, clusters, 8 approche percussive du piano, langage harmonique postimpressionniste et structures fluides. Par son charisme, Ornstein donne un coup d'envoi à la musique moderne américaine : « Avec un don pour la flamboyance et la self-promotion, Ornstein apportait un premier modèle de la façon dont un compositeur de la modernité pouvait faire une carrière aux États-Unis. » 9 Le compositeur californien Henry Cowell (1897-1965), qui rencontre Ornstein à New York, compose Dynamic Motion (1916) et The tides of Manaunaun (1917), dans lesquels il demande à un pianiste de jouer des clusters en frappant les touches du clavier avec le poing, la paume de la main ou l'avant bras. Dans Aeolian Harp (1923), il demande de frapper, de balayer et de pincer les cordes à l'intérieur du piano. À partir des années 1920, une conscience musicale différente de celle de l'Europe commence à émerger, notamment à New York qui va devenir progressivement un centre majeur de création artistique. New York est une ville cosmopolite qui accueille, par vagues successives, de nombreux réfugiés et apatrides. La ville devient un véritable vivier intellectuel et artistique recevant sans a priori les idées nouvelles venues de l'Europe. Des organisations collectives pour la nouvelle musique américaine commencent à apparaître, telles que l'International Composers' Guild (1921-1927), le 7 Trad. : « The decade between 1910 and 1920 was the mysterious Paleolithic period of American modernist music. Occasional glints of activity were overshadowed by a near singleminded focus on historic European repertories.

... The thermoelectric module is clamped between a cooling jacket and a heater block. The heater block is made from aluminum. ... To control the hot-end temperature T H , the coolant flow through the cooling jacket is turned on and off by two control valves installed in the flow lines. ...

A distance relaying scheme is susceptible to power swing. To avoid unintended trip operation during such conditions, a power swing blocking function is utilized in distance relays. However, if a fault occurs during power swing, the relay should detect the fault and trip as soon as possible. The detection of fault in a series-compensated line during the power swing is further complicated due to complex transients produced by series capacitor and the metal-oxide varistor (MOV) protecting it. This paper proposes a negative-sequence current-based technique for detecting all types of faults during the power swing in a series-compensated line. The technique is tested for different series-compensated systems including a 9-bus 3-machine power system. Different types of faults: symmetrical, asymmetrical, and high resistance occurring during the power swing are simulated through EMTDC/PSCAD to test the algorithm. The method is compared with available techniques and found to be accurate and fast.

This paper presents a synergetic controller for pulse current charging of advanced batteries from a fuel cell power source. Pulse current charging protocol that has been shown to have many advantages over the traditional constant current/constant voltage protocol is applied in a fuel cell powered battery-charging station to reduce the total charging time. Strong nonlinearity and dynamics exist in such systems. In this paper, the synergetic control approach is applied to regulate the buck converters that control the pulse charging currents to the many batteries. A practical synergetic controller to coordinate pulse current charging of the battery is synthesized and discussed. It provides asymptotic stability with respect to the required operating modes, invariance to load variations, and robustness to variation of the input and converter parameters. The synergetic controller is then implemented in Simulink. The dynamic characteristics of the synergetic controller are studied and compared with PI controller by conducting system simulation and experimental tests. Simulation and experiment results show the synergetic controller is robust for such nonlinear dynamic system and achieves better performance than the standard PI controller.

SUMO is an open source traffic simulation package including net import and demand modeling components. We describe the current state of the package as well as future developments and extensions. SUMO helps to investigate several research topics e.g. route choice and traffic light algorithm or simulating vehicular communication. Therefore the framework is used in different projects to simulate automatic driving or traffic management strategies.