Dynamic Behaviour

Abstract—This paper reports on the control structure of the pneumatic biped Lucy. The robot is actuated with pleated pneumatic artificial muscles, which have interesting characteristics that can be exploited for legged machines. They have a high power to weight ratio, an ...

We test herein the hypothesis that the succession of low tides-during which biomass increases-and high tides-during which biomass decreases-controls the dynamic behaviour of the microphytobenthic compartment. Results indeed show that during a complete lunar cycle Abridged version (see p. 507) Note p&e&e par Michel Thellier

This paper describes the dynamic behaviour of a doubly-fed induction machine, operating with wind turbine. The rotor circuit of the machine consists only of a generator-side converter working under abnormal condition at stator side (fault condition and voltage drop take place in transmission lines of the grid system). The induction machine model is based on the stationary reference frame and the control-unit model is based on the line-voltage oriented reference frame. The generator-side controller provides good decoupling between active and reactive power. A powerful MATLAB/SIMULINK was used for the simulation of the wind energy conversion system of a 4 kW wind generator. The simulation results of the generator side converter show that the speed, torque and the ϕ sin (power factor) can be regulated independently to match the reference signals. The effects of assumed abnormal condition in the grid system are discussed with regard to stator current and rotor current of the induction m...

This report was prepared as an account of work sponsored by an agency of the United States Government. Neither the United States Government nor any agency thereof, nor any of their employees, makes any warranty, express or implied, or assumes any legal liability or responsi. bility for the accuracy, completeness, or uselulness of any information, apparatus, product, or process disclosed, or represents that its use would not infringe privately owned rights. Reference herein to any specific commercial product, process, or service by trade name, trademark, manufacturer, or otherwise does not necessarily constitute or imply its endorsement, recommendation, or favoring by the United States Government or any agency thereof. The views and opinions of authors expressed herein do not necessarily state or reflect those of the United States Government or any agency thereof.

Immersive visualisation is increasingly being used for comprehensive and rapid analysis of objects in 3D and object dynamic behaviour in 4D. Challenges are therefore presented to provide natural user interaction to enable effortless virtual object manipulation. Presented in this paper is the development and evaluation of an immersive human-computer interaction system based on stereoscopic viewing and natural hand gestures. For the development, it is based on the integration of a back-projection stereoscopic system for object and hand display, a hybrid inertial and ultrasonic tracking system to provide the absolute positions and orientations of the user's head and hands, as well as a pair of high degrees-of-freedom data gloves to provide the relative positions and orientations of digit joints and tips on both hands. For the evaluation, it is based on a two-object scene with a virtual cube and a CT (computed tomography) volume created for demonstration of real-time immersive object manipulation. The system is shown to provide a correct user view of objects and hands in 3D with depth, as well as to enable a user to use a number of simple hand gestures to perform basic object manipulation tasks involving selection, release, translation, rotation and scaling. Also included in the evaluation are some quantitative tests of the system performance in terms of speed and latency.

The increasing demand for more fuel efficiency and environmentally friendly cars coupled with the consumers' drive for more comfort, safety and luxury has led to the introduction of more electrical and electronic systems in the passenger car. This is further impacted by the current trend in automotive industry to replace mechanical and hydraulic systems with their electrical counterparts. The handling

ISO tank containers are used to transport bulk liquids by road, rail and sea. The tank itself is designed using ASME regulations, while the frame designs have evolved through experience. The primary area of concern is the attachment of the tank to the frame as this does not lend itself to analysis using traditional mechanics. The design objective is to reduce the overall weight of the container, thereby allowing greater payloads, as the total laden weight of the container is controlled. Traditionally containers have been built and then tested statically, but there is now a growing emphasis on the dynamic behaviour of the tank, particularly with the ISO introduction of a compulsory dynamic impact test. This paper discusses the finite element modelling of the tank container, statically and dynamically, for road and rail conditions. The static conditions are modelled using the implicit solver in ANSYS 5.6, and the dynamic conditions are modelled using the ANSYS pre-processor and LSDYNA explicit solver. Using the FEA results a new modular tank and frame was designed and built. This tank was then tested in France according to Llyods certification standards. The results from these tests were used to validate and refine the computer model. The paper will discuss the following aspects of the project: Static modelling of the tank and support structure and verification of the model using, static load data gathered from prototype testing. Crash test methods and mathematical modelling. Dynamic FEA modelling to simulate a standard ISO crash test and verification of the model by comparison with SNCF crash test results obtained from the prototype. Design modifications to improve the tank performance during impact.

By analysing the temperature of the external surface during the application of cyclic loading, it is possible to evaluate the dynamic behaviour of an element and to determine the fatigue limit. The methodology (Risitano method) does not need any particular testing machine and allows reliable results to be obtained using a very limited number of specimens in a very short time. This methodology also yields information on the energy retained by the specimen and mechanical components. The results of 15 years of research into a new methodology for the determination of the fatigue limit of materials or mechanical components are reported.

This paper presents a dynamic simulator of the semi-autogenous grinding operation deduced from first principles coupled to an on-line parameter estimation scheme able to simulate industrial operations for control purposes. Model equations are based on conventional non-stationary population balance approach to develop the necessary dynamic model of the semi-autogenous mill operation. The model is able to predict the time-evolution of key operating variables such as product flow rate, level charge, power-draw and load position, as function of other important variables such as mill rotational speed and fresh feed characteristics. The set of ordinary differential equations was solved using MATLAB/SIM-ULINK as a graphic programming platform, a very helpful tool for understanding the grinding phenomenon.

Entangled states play a crucial role in quantum information protocols, thus the dynamical behavior of entanglement is of a great importance. In this paper we consider a two-mode squeezed vacuum state coupled to one thermal reservoir as a model of an entangled state embedded in an environment. As a criterion for entanglement we use a continuous-variable equivalent of the Peres-Horodecki criterion, namely the Simon criterion. To quantify entanglement we use the logarithmic negativity. We derive a condition, which assures that the state remains entangled in spite of the interaction with the reservoir. Moreover for the case of interaction with vacuum as an environment we show that a state of interest after infinitely long interaction is not only entangled, but also pure. For comparison we also consider a model in which each of both modes is coupled to its own reservoir.

the increasing demand for more fuel efficiency and environmentally friendly cars coupled with the consumers' drive for more comfort, safety and luxury has led to the introduction of more electrical and electronic systems in the passenger car. This is further impacted by the current trend in automotive industry to replace mechanical and hydraulic systems with their electrical counterparts. The handling capability of the current 14V DC system is getting very close to reaching its limits. To meet the new growing electrical power demands with minimum fuel consumption and minimum environmental effects, the automobile industry is looking into increasing the present voltage threefold, from 14V to 42V for future cars.

In this contribution we show how the phenomenological theory of sedimentation-consolidation processes can be extended to the presence of centrifugal field. The modelling starts from the basic mass and linear momentum balances for the solid and liquid phase, which are referred to a rotating frame of reference. These equations are specified for flocculated suspensions by constitutive assumptions that are similar to that of the pure gravity case. The neglection of the influence of the gravitational relative to the centrifugal field and of Coriolis terms leads to one scalar hyperbolicparabolic partial differential equation for the solids concentration distribution as a function of radius and time. Both cases of a rotating tube and of a rotating axisymmetric vessel are included. A numerical algorithm to solve this equation is presented and employed to calculate numerical examples of the dynamic behaviour of a flocculated suspension in a sedimenting centrifuge. The phenomenological model is appropriately embedded into the existing theories of kinematic Ž. centrifugation processes of ideal non-flocculated suspensions.

Purpose-Success of a television game show requires brand-building effort and brand value management like any other product. However, aspects of information, entertainment, novelty, instant gratification, and experience dimensions are more salient in game shows. This has been amply proven by the television game show Who Wants To Be A Millionaire. The purpose of this research is to explore why some entertainment products succeed, while others fail. Design/methodology/approach-In this paper, we present the system dynamic model of brand management of the game show Kaun Banega Crorepati (KBC), the Indian version of Who Wants To Be A Millionaire. Initially, we present the reference mode behaviour, drawn from published data. In the dynamic model, we include factors such as channel popularity, host popularity, prize money, and competition that work towards building the viewership and influencing operational revenues. Computer-based simulation and experimentalism are then applied as a research method to the model to explore its dynamic behaviour. Findings-Our analysis shows that the right mix of host popularity, channel popularity and prize money has enabled KBC to achieve unprecedented success. Research limitations/implications-Validation of the model is based on the strength that the simulation results can replicate the reference mode behaviour and produce behaviour expected under extreme conditions. The validated model is used to draw what-if scenarios, some of which resemble the experiences of competing game shows. Originality/value-Understanding the dynamics of brand management of this game show can serve as an important tool for brand management of entertainment products. Further, the use of system dynamics for dynamic modelling of brand value has application in broader areas of marketing, and would be of interest to a wide managerial audience.

Ball bearings in space mechanisms are subjected to vibration during launch which can lead to a temporary loss of contact between the balls and the raceway. On re-establishing contact the transient high contact stresses which arise may cause damage to the bearing. This transient loss of contact is referred to as "gapping". Despite the fact that it is clearly of interest to understand how exposure to the launch vibration impacts upon bearing and lubricant performance, the dynamic behaviour of bearings subjected to vibration typical of that occurring during launch has been little studied. This paper describes a theoretical and experimental investigation to examine the influence of simulated launch vibration on the torque performance of solid and liquid lubricated ball bearings. A fixture containing a pair of preloaded face-to-face angular contact bearings was mounted on an electro-dynamic vibrator. Two laser triangulation transducers were used to measure the relative axial displacement of the bearing components at a range of acceleration levels. A simple analytical model was also developed to predict gapping for a range of different test conditions. Data from this model was compared to measured gapping. The effect of vibration on bearing torque was measured following each level of acceleration. Finally, features arising in the bearing raceway due to vibration testing were assessed.

The problem of the evaluation of the seismic vulnerability of hospital buildings, whose structures often do not respect prescriptions of modern codes, is tackled through a structural identification procedure. In this paper an integrated numerical-experimental methodology is illustrated: forced dynamic tests with harmonic excitation (vibrodyne) are carried out on the existing building and the analysis of signals recorded by accelerometers fixed in several points of the structure is performed; at the same time a finite element model of the structure is built and the modal analysis is performed. The comparison of the results enables to verify and calibrate numerical predictions on the base of data obtained from modal testing: then, calibrated FEM models can be used to simulate the effect of small earthquakes, the structural linear response to which can be assumed as a good approximation. Moreover it is possible to extrapolate the building's response to greater intensity earthquakes.

Nonlinear static and dynamic behaviours of freely supported Rhombic sandwich plates have been studied following Banerjee's hypothesis. Numerical results for 0 ° skew angle are compared with other known results. Results for other skew angles are believed to be new. Sommario. Si studia, seguendo l'ipotesi di Banerjee, il comportamento nonlineare statico e dinamico di piastre rombiehe semplicemente appoggiate. Si presentano fisultati numefici relativi a piastre rombiche e rettangolari: questi ulfimi vengono paragonati a risultati gi~ nofi, mentre i primi si fitengono nuovi.

Testing embedded systems is inherently incomplete; no test suite will ever be able to test all possible usage scenarios. Therefore, in the past decades many coverage measures have been developed. These measures denote the portion of a system that is tested, that way providing a quality criterion for test suites. Formulating coverage criteria is not an easy task. The measures provided in the literature are consequently almost all very trivial and syntax-dependent. Well-known examples are statement and path coverage in white-box testing, and state and transition coverage in black-box testing. The complexity of designing coverage measures for embedded systems is contained in the highly dynamic behaviour of such systems, which is state-dependent and subject to many interleavings. In this talk we introduce a framework on actual test coverage. This measure denotes the number of faults actually shown present or absent. Our framework contains a method to evaluate the actual coverage of a gi...

This paper presents a combined experimental and computational study into the aerodynamics and performance of a small scale Vertical Axis Wind Turbine (VAWT). Wind tunnel tests were carried out to ascertain overall performance of the turbine and two and three dimensional unsteady computational fluid dynamics (CFD) models were generated to help understand the aerodynamics of this performance. Wind tunnel performance results are presented for cases of different wind velocity, tip-speed ratio and solidity as well as rotor blade surface finish. It is shown experimentally that the surface roughness on the turbine rotor blades has a significant effect on performance. Below a critical wind speed (Reynolds number of 30,000) the performance of the turbine is degraded by a smooth rotor surface finish but above it, the turbine performance is enhanced by a smooth surface finish. Both two bladed and three bladed rotors were tested and a significant increase in performance coefficient is observed for the higher solidity rotors (three bladed rotors) over most of the operating range. Dynamic stalling behaviour and the resulting large and rapid changes in force coefficients and the rotor torque are shown to be the likely cause of changes to rotor pitch angle that occurred during early testing. This small change in pitch angle caused significant decreases in performance. The performance coefficient predicted by the two dimensional computational model is significantly higher than that of the experimental and the three dimensional CFD model. The predictions show that the presence of the over tip vortices in the 3D simulations is responsible for producing the large difference in efficiency compared to the 2D predictions. The dynamic behaviour of the over tip vortex as a rotor blade rotates through each revolution is also explored in the paper.

In 2003 the IAEA has initiated a Coordinated Research Project (CRP) on "Studies of Advanced Reactor Technology Options for Effective Incineration of Radioactive Waste". Major intermediate results have been obtained and will be reported here. The overall objective of the CRP, performed within the framework of IAEA's Nuclear Energy's Department Technical Working Group on Fast Reactors, is to increase the capability of Member States in developing and applying advanced technologies in the area of long-lived radioactive waste utilization and transmutation. Sixteen institutions from 12 member states and one international organization participated in this CRP. The CRP concentrated on the assessment of the dynamic behaviour of various transmutation systems. The reactor systems investigated comprise critical reactors, subcritical accelerator driven systems with heavy liquid metal and gas cooling, critical molten salt systems and hybride fusion/fission systems. Both fertile and fertile-free fuel options have been investigated. For a deep assessment of the transient and safety behaviour, the analytical capabilities have to be qualified. A major effort of the CRP consisted in the benchmarking of steady state core configurations and performing transient/accident simulations. For a general assessment and comparison, the safety coefficients were determined for the individual systems. In a second step transient analyses were performed which reflected the generic behaviour of the various reactors types. In addition the transmutation potential, burn-up behaviour and decay heat of minor actinide bearing fuels were investigated.

This study, carried out in cooperation with ESSAIM, Ecole Superieure des Sciences Appliquees pour l'Ingenieur, Mulhouse in France, was aimed at developing accurate mathematical models of some types of tyre, in order to analyze their influence on vehicle dynamics. The complete vehicle was studied under dynamic conditions, to quantify the influence of all factors, such as rolling forces, aerodynamic forces and many others, acting on their components on torque distribution and vehicle dynamics. Mathematical models for two common types of vehicle, namely front and rear wheel drive, each ones equipped with the different types of tyre, were developed. Both models were used to simulate the behaviour of a real vehicle, developing complete simulation software, developed in Matlab-Simulink environment at MIPS, Modelisation Intelligence Processus Systemes. Therefore, this car model, running on a straight and curve track, was also developed, to get a qualitative insight of the influence of ...

A reliable machine fault prognostic system can be used to forecast damage propagation trend in rotary machinery and to provide an alarm before a fault reaches critical levels. Currently, there are several techniques available in the literature for time-series prediction. Among the most promising methods are recurrent neural networks (RNNs) and neuro-fuzzy (NF) systems. In this paper, the performance of these two types of predictors is evaluated using two benchmark data sets. Through comparison it is found that if an NF system is properly trained, it performs better than RNNs in both forecasting accuracy and training efficiency. Accordingly, NF system is adopted to develop an on-line machine fault prognostic system. In order to facilitate the automatic monitoring process, reference function approach is proposed here to enhance feature representation. The performance of the developed prognostic system is evaluated by using three test cases including a worn gear, a chipped gear, and a cracked gear, as well as using data sets from previous studies corresponding to a gear pitting damage and a shaft misalignment. From these tests, the NF prognostic system is found to be a very reliable and robust machine health condition predictor. It can capture the system dynamic behaviour quickly and accurately.

Two impulsive models of integrated pest management (IPM) strategies are proposed, one with fixed intervention times and the other with these unfixed. The first model allows natural enemies to survive but under some conditions may lead to extinction of the pest. We use a simple prey-dependent consumption model with fixed impulsive effects and show that there exists a globally stable pesteradication periodic solution when the impulsive period is less than certain critical values. The effects of pest resistance to pesticides are also studied. The second model is constructed in the light of IPM practice such that when the pest population reaches the economic injury level (EIL), a combination of biological, cultural, and chemical tactics that reduce pests to tolerable levels is invoked. Using analytical methods, we show that there exists an orbitally asymptotically stable periodic solution with a maximum value no larger than the given Economic Threshold (ET). The complete expression for this periodic solution is given and the ET is evaluated for given parameters. We also show that in some cases control costs can be reduced by replacing IPM interventions at unfixed times with periodic interventions. Further, we show that small perturbations of the system do not affect the existence and stability of the periodic solution. Thus, we provide the first demonstration using mathematical models that an IPM strategy is more effective than classical control methods.

Tool-support is strongly required in order to ease the use of task models and make them acceptable to a large number of designers. CTTE is an automatic environment that has been developed for this purpose. This tool can be useful to better develop and analyse task models and their dynamic behaviour including those for cooperative applications.

This paper presents theoretical investigations into the dynamic characterisation of a flexible manipulator system. A constrained planar single-link flexible manipulator is considered. A dynamic model of the system, incorporating structural damping and hub inertia, is developed using finite element method. Simulation exercises are performed with bang-bang input torque applied to the actuator. The simulation algorithm thus developed is implemented in Matlab. To study the effects of length on the response of the flexible manipulator, the results are evaluated with varying beam's length in the algorithm. Simulation results are presented in time and frequency domains. Performance of the algorithm in describing the dynamic behaviour of the system is examined in terms of level of vibration frequencies and time response specifications. Finally, a comparative assessment of different beam's length to the system performance is assessed and discussed.

The paper deals with the development of a parallel robotic arm for deep-sea maintenance operations on oil and gas exploitation scaffoldings and piping, at 2000÷3000 m under sea-level. Resort to the innovative architecture looks to be a useful improvement as compared with traditional approaches, due to inherent capabilities in terms of stiffness, accuracy and effectiveness, which grant higher mission success

A forest fire can be a real ecological disaster, regardless of whether it is caused by natural forces or human activity. It is impossible to control nature, but it is possible to map forest fire risk zones and thereby minimise the frequency of fire, avert damage, etc. Forest fire risk zones are ...

Polymeric supports are presented as an alternative to granular activated carbon (GAC) for organic contaminants removal from waste waters from industrial processes. The present work describes the sorption of an azo dye (Acid red 14) from aqueous solution onto Macronet polymeric sorbent MN200 and MN300. Batch experiments were performed to determine loading isotherms and loading rates at different pH. The behaviour of a non-functionalized Macronet support MN200 was compared with Macronet MN300 containing tertiary amine groups. The loadings achieved were 65 g kg À1 for MN200 and 108 g kg À1 for MN300. The influence of the acidity on dye removal was notable; the decrease of pH provides an increase on the loading around 100% of the value reported at neutral pH. Equilibrium data were modelled with Langmuir, Freundlich and Redlich-Peterson isotherms. The hyper-cross-linked polymers extract Acid red 14, via a complex sorption process depending on the aqueous feed composition and depending on the nature of the sorbent evaluated. The Redlich-Peterson isotherm provides a better description of sorption data for both resins. Kinetic experiments were carried out for both sorbents at different pH and azo dye concentrations. Three theoretical models (pseudo-first, pseudo-second-order reaction and the Elovich model) were used to describe the Acid red 14 sorption kinetics, and to determine the sorption rate constants by graphical and numerical analysis of the experimental data by using the proposed models. The study showed that sorption systems followed a pseudo-first-order reaction model although the pseudo-second-order reaction model provides a good description of the sorption process. Column experiments were performed in order to compare the dynamic behaviour of the sorbents and their capacity of regeneration. Non-functionalized MN200 resin showed excellent behaviour during the regeneration process. After 3 bed volumes the amount of Acid red 14 eluted was almost 100%.

With the aim of providing a tool for the comprehensive seismic analysis of steel moment resisting frames (MRFs), the paper presents the development of a structural model which is able to describe the deformation modes of the panel zone in beam-tocolumns joints, without resorting to a computationally heavy FE discretization. The model is able to take into account the finite dimensions of the joint, differently from the ''scissor model'' currently adopted, and can incorporate the most recently proposed constitutive models for monotonic and cyclic loading. The proposed approach, based on a simple structural representation of the joint, does not modify the centre-to-centre line scheme and the nodal degrees of freedom usually adopted in the analysis of plane frames, but adds up to five more degrees of freedom to each node. These describe the deformation modes of the panel zone, namely extensional, flexural and due to shear. A non-linear behaviour can be associated to each of these modes; based on experimental results, a simple hysteretic model is proposed for the shear deformation. The panel zone model has been implemented in an ad hoc developed computer code for the non linear seismic analysis of steel MRFs (named STEFAN, STEel Frame ANalysis), including a non-linear fracturing beam model as well. As an example of application, the dynamic behaviour of a 5-bay 9-story frame designed according to Eurocodes 3 (EC3) and 8 (EC8) has been investigated, for different panel zone stiffness and with different models, both in the linear and non linear range, emphasizing the need for a correct panel zone modelling.

The objective of the paper is to present a mathematical model for analysis of prestressed cable structures with flexible contour beam. The proposed numerical procedures are based on a discrete scheme according to the finite element method. A reliable model of the interaction of the flexible contour beam with the cable network enables the achievement of more efficient solutions in the design analysis. Geometrical nonlinearity is accounted for in the cable net substructure and the contour beam is modelled by linear beam elements. Equations are solved by iterative methods and explicit time integration. The described numerical technique has been employed to model prestressing, static and dynamic behaviour. Theoretical results have been compared to experimental data and used in practical applications.

This paper reports on the control structure of the biped Lucy. The robot is actuated with pleated pneumatic artificial muscles which have interesting characteristics that can be exploited for legged machines. They have a high power to weight ratio, an adaptable compliance and they reduce impact effects. The considered control structure can be divided into two parts: a real-time joint trajectory generator and a trajectory tracking controller. The latter consists of a computed torque controller, a delta-p unit, a PI controller and a bang-bang pressure controller. The trajectory generator provides polynomial joint trajectories while the computed torque in combination with the delta-p unit calculates the required muscle pressure levels. The PI and bang-bang controller work at pressure level to cope with modelling errors and to set the pressures in each muscle. The proposed control architecture is evaluated with a full hybrid dynamic simulation model of the biped. This simulator combines the dynamical behaviour of the robot with the thermodynamical effects that take place in the muscle-valves system. The observed hardware limitations of the real robot and expected model errors are taken into account in order to give

The Solar Electron and Proton Telescope (SEPT), one of four instruments of the Solar Energetic Particle (SEP) suite for the IMPACT investigation, is designed to provide the three-dimensional distribution of energetic electrons and protons with good energy and time resolution. This knowledge is essential for characterizing the dynamic behaviour of CME associated and solar flare associated events. SEPT consists of two dual double-ended magnet/foil particle telescopes which cleanly separate and measure electrons in the energy range from 30-400 keV and protons from 60-7 000 keV. Anisotropy information on a nonspinning spacecraft is provided by the two separate telescopes: SEPT-E looking in the ecliptic plane along the Parker spiral magnetic field both towards and away from the Sun, and SEPT-NS looking vertical to the ecliptic plane towards North and South. The dual setup refers to two adjacent sensor apertures for each of the four view directions: one for protons, one for electrons. The double-ended setup refers to the detector stack with view cones in two opposite directions: one side (electron side) is covered by a thin foil, the other side (proton side) is surrounded by a magnet. The thin foil leaves the electron spectrum essentially unchanged but stops low energy protons. The magnet sweeps away electrons but lets ions pass. The total geometry factor for electrons and protons is 0.52 cm 2 sr and 0.68 cm 2 sr, respectively. This paper describes the design and calibration of SEPT as well as the scientific objectives that the instrument will address.

The main concern of this research work is to analyse and model supply chains (SCs) in the particular context of small and medium enterprises (SMEs) in the field of mechatronic. The study is based on the analysis of the organisational features, the actors' behaviour, and performance considerations. The development of the model relies on an iterative framework that progressively integrates different aspects into the model. This framework is the ArchMDE process, which is based on MDE (Model Driven Engineering). A major feature of this work lies in its contribution to two different areas of research. The first contribution of the work is to propose a generic metamodel for SCs. Based on a literature review, an incremental framework is proposed for the modelling of SCs in terms of concepts, structure and relationships. The application of the framework to the studied context is described and its result is a domain-metamodel for SCs. The second contribution of this work lies in the formalisation of the dynamic behaviour of the concepts in the metamodel. This formalisation is based on the multi-agent approach. An agentification of the metamodel is thus drawn, thanks to the natural links between multiagent theory and SC reality. This step leads to an agentified-domain-metamodel which also includes the monitoring of the SC and synchronisation protocols. By adding relationships and dynamic behavior aspects, we obtain a 2 metamodel of the domain that can be implemented, with its static and dynamic aspects. To validate this model, an industrial case study is detailed and has been instantiated and encoded in JAVA.

Use of power electronic equipment has increased and introduced new dynamical phenomena in power systems. For example, new electric rail vehicles (locomotives) equipped with modern power electronic traction chains have caused situations of low frequency power oscillations and instability in singlephase railway power supply systems. This paper presents the development and implementation of an instantaneous value model and simplified fundamental frequency (RMS) models of such an advanced electric rail vehicle in order to investigate their representation of low-frequency dynamics. The dynamical behaviour is studied by use of both time-domain simulations and linear analysis (eigenvalues) and the degree of simplifications regarding controller dynamics and power system dynamics are presented and discussed. An enhanced RMS model is tested in order to account for the impact of fast current dynamics on the low-frequency behaviour. The results show that this enhanced model is corresponding more closely to the instantaneous value model than what can be obtained by the traditional RMS simplifications and indicate that current dynamics should be included in stability studies involving power electronic inverters.

We formulate a deterministic model with two latent periods in the non-constant host and vector populations, in order to theoretically assess the potential impact of personal protection, treatment and possible vaccination strategies on the transmission dynamics of malaria. The thresholds and equilibria for the model are determined. The model is analysed qualitatively to determine criteria for control of a malaria epidemic and is used to compute the threshold vaccination and treatment rates necessary for community-wide control of malaria. In addition to having a disease-free equilibrium, which is locally asymptotically stable when the basic reproductive number is less than unity, the model exhibits the phenomenon of backward bifurcation where a stable disease-free equilibrium coexists with a stable endemic equilibrium for a certain range of associated reproductive number less than one. From the analysis we deduce that personal protection has a positive impact on disease control but to eradicate the disease in the absence of any other control measures the efficacy and compliance should be very high. Our results show that vaccination and personal protection can suppress the transmission rates of the parasite from human to vector and vice-versa. If the treated populations are infectious then certain conditions should be satisfied for treatment to reduce the spread of malaria in a community. Among the interesting dynamical behaviours of the model, numerical simulations show a backward bifurcation which gives a challenge to the designing of effective control measures.

The response of a flow-through biosensor is the consequence of complex interrelations between the dilution of the sample in a continuous stream (governed by physical variables) and the phenomena involved in the reactions between enzyme and substrate (governed by diffusion and kinetic processes). These interrelations make it difficult to know in advance the influence of manifold parameters in the biosensor response. If a reliable model of these processes is attainable, it will be possible to test rapidly, by computer, the effect of the variation of different operating variables on the response of the biosensor. This paper presents the results obtained when two models are applied to describe dynamic behaviour of a potentiometric flow-through urea biosensor. One of these models uses an empirical approach based on neural networks, while the other proposes a deterministic approach that takes into account reaction-diffusion equations.

Large flexible structures and aerospace structures can be studied by building a model flexible beam with an appendage. The appendage can be used as a passive or an active vibration absorber for a structure under sinusoidal and random excitation. In this study, a cantilever beam-tip mass-pendulum system is investigated by using Finite Element method (FEM). Dynamical behaviour of the model

th August 2009 Literature shows that exchange rates are largely unpredictable, and that a simple random walk outperforms structural exchange rate models. In order to determine whether fundamentals explain exchange rate behaviour in South Africa, the two approaches to exchange rate forecasting - the technical and fundamental approach - will be compared. Various univariate time series models, including the random walk model, will be compared to various multivariate time series models (using the MAD/mean ratio), combining the two approaches. The determinants of the South African exchange rate are identified, and these determinants are used to specify multivariate time series models for the South African exchange rate. The multivariate models (VARMA) outperformed the univariate models (except for the Random walk model) in the short-run forecasts, one step ahead, while the multivariate models, performed better in the longer-run forecasts. To improve the accuracy of especially the multiva...

The modeling and simulation of the dynamic behavior of organizational systems is essential for understanding their current functionality and for supporting business process analysis and reengineering. The behavior of organizational systems is viewed here in terms of the behavior of their business processes. Multi-level Modified Petri nets are used as the underlying formalism for modeling and simulating organizational systems behavior at various abstraction levels. Each level of abstraction corresponds to one or more levels of the involved part of the organizational hierarchy. The constructed models represent existing or redesigned business processes. Simulation and graphical animation are used for discovering problems in existing business processes as well as in the proposed solutions. The whole approach is supported by a development environment called ERMIS.

A detailed nonlinear time series analysis of the hourly data of the geomagnetic horizontal intensity H measured at Kodaikanal (10.2 • N; 77.5 • E; mag: dip 3.5 • N) has been carried out to investigate the dynamical behaviour of the fluctuations of H. The recurrence plots, spatiotemporal entropy and the result of the surrogate data test show the deterministic nature of the fluctuations, rejecting the hypothesis that H belong to the family of linear stochastic signals. The low dimensional character of the dynamics is evident from the estimated value of the correlation dimension and the fraction of false neighbours calculated for various embedding dimensions. The exponential decay of the power spectrum and the positive Lyapunov exponent indicate chaotic behaviour of the underlying dynamics of H. This is also supported by the results of the comparison of the chaotic characteristics of the time series of H with the pseudo-chaotic characteristics of coloured noise time series. We have also shown that the error involved in the short-term prediction of successive values of H , using a simple but robust, zero-order nonlinear prediction method, increases exponentially. It has also been suggested that there exists the possibility of characterizing the geomagnetic fluctuations in terms of the invariants in chaos theory, such as Lyapunov exponents and correlation dimension. The results of the analysis could also have implications in the development of a suitable model for the daily fluctuations of geomagnetic horizontal intensity.

Service-oriented computing, an emerging paradigm for distributed computing based on the use of services, is calling for the development of tools and techniques to build safe and trustworthy systems, and to analyse their behaviour. Therefore many researchers have proposed to use process calculi, a cornerstone of current foundational research on specification and analysis of concurrent and distributed systems. We illustrate this approach by focussing on COWS, a process calculus expressly designed for specifying and combining services, while modelling their dynamic behaviour. We present the calculus and one of the analysis techniques it enables, that is based on the temporal logic SocL and the associated model checker CMC. We demonstrate applicability of our tools by means of a large case study, from the financial domain, which is first specified in COWS, and then analysed by using SocL to express many significant properties and CMC to verify them.