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At a time when most professions are undergoing massive automation and transformation there are still quite a few professions that have not changed in the past fifty years. One of those professions is chimney sweeping. This thought led to the initial idea for this paper. In this paper, we have proposed a design of an in-pipe robot that could be used for chimney cleaning and inspection. Mathematical modelling of the movement of the robot and actuators was carried out, which allowed us to study the proposed design. Since the mathematical model is quite abstract, computer simulations were done in order to prove the mathematical model, with the possibility to further parameters adjustment of the robot. After the simulations were concluded, the total distance and total time of one cycle of the actuator were obtained. [ABSTRACT FROM AUTHOR]

A key parameter of the linear programming (LP) models widely used for production planning in industry and academia are the lead times, the estimated delay between material becoming available to a resource and its completion at that resource. Lead times are commonly treated as exogenous, workload-independent parameters and assumed to be integer multiples of the planning period. Although formulations with non-integer lead times have been implemented in industry, we are unaware of any studies systematically evaluating their performance. In this paper, we compare the performance of LP models with and without non-integer lead times by simulating the execution of the resulting release plans. We also compare their performance to that of a formulation incorporating workload-dependent lead times using nonlinear clearing functions. We find that the performance of the models with non-integer lead times is substantially better than those with integer lead times, and often superior to that of the much more complex clearing function models. These results suggest that whenever reasonable estimates of the lead times are available, non-integer lead times should be used due to their simplicity of implementation and excellent performance. [ABSTRACT FROM AUTHOR]

Copyright of LogForum is the property of LogForum and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Health care is a complex system with multiprofessional staff and multiple patient care pathways. Time pressure and minimal margins for error make it challenging to implement new policies or procedures, no matter how desirable. Changes in health care also requires the participation of the staff. System dynamics (SD) simulations can lead to shared systems understanding and allows for the development and testing of new scenarios in silico before implementing solutions. However, research shows that the actual implementation rate of simulations is low. This paper presents a reanalysis of a successful change project in health care combining SD principles with basic action research (AR) premises. The analysis was done by a multidisciplinary research group using qualitative methodology and identifies that a fruitful combination of AR inquiry and SD modelling potentially can improve implementation rates. [ABSTRACT FROM AUTHOR]

In this paper, we propose and analyze a nonlinear mathematical model to study the effect of skill development on unemployment. We assume that government promulgates different levels of skill development programs for unemployed persons through which two different categories of skilled persons, namely, the low-skilled and the highly-skilled persons, are coming out and the highly-skilled persons are able to create vacancies. The model is studied using stability theory of nonlinear differential equations. We find analytically that there exists a unique positive equilibrium point of the proposed model system under some conditions. Also, the resulting equilibrium is locally as well as globally stable under certain conditions. The effective use of implemented policies to control unemployment by providing skills to unemployed persons and the new vacancies created by highly-skilled persons are identified by using optimal control analysis. Finally, numerical simulation is carried out to support analytical findings. [ABSTRACT FROM AUTHOR]

This paper presents the mathematical model and numerical analysis of the convective drying process of thick slices of colloidal capillary-porous materials slowly moving through conveyor-belt dryer. A flow of hot moist air was used as drying agent. The drying process has been analyzed in the form of a 2-D mathematical model, in two directions: along the conveyor and perpendicular on it. The mathematical model consists of two non-linear differential equations and one equation with a transcendent character and it is based on the mathematical model developed for drying process in a form of a 1-D thin layer. The appropriate boundary conditions were introduced. The presented model is suitable for the automated control of conveyor-belt dryers. The obtained results with analysis could be useful in predicting the drying kinetics of potato slices and similar natural products. [ABSTRACT FROM AUTHOR]

Temperature fields in electric energy generators may lead to mechanical dissbalance of an already balanced rotor. The author collected information in a number of steam power plants and confirmed the existence of the problem. This paper presents the specific case of thermal deformation of the rotor, caused by an asymmetrical temperature field in scale of rotor. On the grounds of the relevant physical aspects, we proposed a mathematical model identifying fields in a turbo generator rotor and suggest the optimum control by which the unwanted effects are eliminated. [ABSTRACT FROM AUTHOR]

This paper presents modeling guidelines and a benchmark system for power system simulation studies of grid-connected, three-phase, single-stage Photovoltaic (PV) systems that employ a voltage-sourced converter (VSC) as the power processor. The objective of this work is to introduce the main components, operation/protection modes, and control layers/schemes of medium- and high-power PV systems, to assist power engineers in developing circuit-based simulation models for impact assessment studies, analysis, and identification of potential issues with respect to the grid integration of PV systems. Parameter selection, control tuning, and design guidelines are also briefly discussed. The usefulness of the benchmark system is demonstrated through a fairly comprehensive set of test cases, conducted in the PSCAD/EMTDC software environment. However, the models and techniques presented in this paper are independent of any specific circuit simulation software package. Also, they may not fully conform to the methods exercised by all manufacturers, due to the proprietary nature of the industry. [ABSTRACT FROM AUTHOR]

In the above paper, Iannazzo et al. propose an improvement of the compact model by introducing a new expression for the description of the bias-dependent saturation velocity. They compare their model to simulation results using the compact model. We comment on this paper, since Iannazzo et al. use inappropriate parameter values for the compact model. We further show that with suitable parameter values, the results from both models are very close. [ABSTRACT FROM AUTHOR]

Numerical simulation of shielding effectiveness (SE) of a perforated shielding enclosure is carried out, using the finite element method (FEM). Possibilities of model definitions and differences between 2D and 3D models are discussed. An important part of any simulation is verification of the model results-here the simulation result are verified in terms of convergence of the model in dependence on the degrees of freedom (DOF) and by measurements. The experimental method is based on measurement of electric field inside the enclosure using an electric field probe with small dimensions is described in the paper. Solution of an illustrative example of SE by FEM is shown and simulation results are verified by experiments. [ABSTRACT FROM AUTHOR]

In trustworthy service discovery for Mobile Social Networking in Proximity (MSNP), conventional trust computation faces a big challenging issue—relatively high latency. To cope with it, trustworthiness determination strategies were proposed in our previous study, aiming at avoiding trust computation under certain conditions, so as to reduce the latency. These strategies are conceived based on the assumption that data of a user's past experience and current profile could be used, and they are incorporated with a set of thresholds from the analysis result of these data. The settings of these thresholds directly affect service quality and user satisfaction on the MSNP service, which in turn becomes an optimization problem. In this paper, we focus on formulating this optimization problem and demonstrating the effectiveness of our proposed solution by designing a simulation experiment. In detail, we establish mathematical models and adjust parameters. We conduct simulations on MATLAB and analyze the results obtained under several different settings. We further compare our work with related works. The results show that our proposed solution is practically feasible and effective in reducing latency under certain conditions. [ABSTRACT FROM AUTHOR]

This paper presents a mathematical model of hydro power units, especially the governor system model for different operating conditions, based on the basic version of the software TOPSYS. The mathematical model consists of eight turbine equations, one generator equation, and one governor equation, which are solved for ten unknown variables. The generator and governor equations, which are different under various operating conditions, are presented and discussed in detail. All the essential non-linear factors in the governor system (dead-zone, saturation, rate limiting, and backlash) are also considered. Case studies are conducted based on one Swedish hydro power plant (HPP) and three Chinese plants. The simulation and on-site measurements are compared for start-up, no-load operation, normal operation, and load rejection in different control modes (frequency, opening, and power feedback). The main error in each simulation is also discussed in detail. As a result, the model application is proved trustworthy for simulating different physical quantities of the unit (e.g., guide vane opening, active power, rotation speed, and pressures at volute and draft tube). The model has already been applied effectively in consultant analyses and scientific studies. [ABSTRACT FROM AUTHOR]

Modeling and simulation are used to support a wide range of applications including design, analysis, operations research, test and evaluation, training, etc. Each application has different fidelity requirements and computational limitations. Consequently, a variety of models are required to support a single aircraft type throughout its life cycle. Validation and configuration management of this array of models is costly. FLIGHTLABis a software tool that supports selective fidelity modeling and simulation to insure trace-ability and commonality between models, ranging from the comprehensive models required for design to the real time models required for training and hardware-in-the-loop testing. Providing a single tool with this range of modeling options greatly enhances the configuration management capability. Also once the highest fidelity, comprehensive, model is validated, it can be used to provide reference data for validation of simpler models, thereby expediting the validation process for all levels of modeling. This paper describes the real-time simulation capability of FLIGHTLABmodels and their trace-ability to higher level FLIGHTLABmodels. [ABSTRACT FROM AUTHOR]

Discrete event simulation (DES) has been widely applied to modelling and simulation of computer and engineering systems and is an active field of research that has now evolved from 2D to 3D discrete event simulation. This paper attempts to address several key issues in a successful implementation of DES models based on our own and the previous experiences of others. It describes the common basis, which forms the core for the application of modelling and simulation methodologies that are available to support manufacturing systems analysis, design and performance evaluation. Through a comprehensive literature survey, this paper summarises and compares the most widely used optimisation techniques for simulation of manufacturing systems; an overview of the recent and popular simulation languages and packages available for the modelling and simulation community and the classification of their utility for modelling and simulation of manufacturing systems is also given. Finally, this paper summarises and reports the latest development in the most exciting world wide web (www)-based simulation techniques that represent a future that may completely change the nature and future exploitation of modelling and simulation technology in industry. [ABSTRACT FROM AUTHOR]

The main goal of this paper is to describe a new multistage Monte Carlo (MMC) simulation method for solving influence diagrams using local computation. Global methods have been proposed by others that sample from the joint probability distribution of all the variables in the influence diagram. However, for influence diagrams having many variables, the state space of all variables grows exponentially, and the sample sizes required for good estimates may be too large to be practical. In this paper, we develop a MMC method, which samples only a small set of chance variables for each decision node in the influence diagram. MMC is akin to methods developed for exact solution of influence diagrams in that we limit the number of chance variables sampled at any time. Because influence diagrams model each chance variable with a conditional probability distribution, the MMC method lends itself well to influence diagram representations. [ABSTRACT FROM AUTHOR]

This paper presents a computational heat transfer model of a rotary kiln used for the production of rutile titanium dioxide by the calcination of paste-like hydrous titanium dioxide. The work details the modelling of several chemical reactions occurring in the solid bed region along with turbulent convection of gas, radiation heat exchange among hot gas, refractory wall and the solid surface, and conduction in the refractory wall. Finite-difference techniques are used and the steady state thermal conditions are assumed. The kiln is divided into axial segments of equal length. The solution is of marching type and proceeds from the solid inlet to the solid outlet. The direction of gas flow is opposite to that of the solids. Mass balance of each species in the solid charge, and mass and energy balances of the solid and gas in an axial segment are used to obtain solids and gas temperatures, and species concentration at the exit of that segment. The kiln length predicted by the present model is 45.75 m as compared to 45 m of an actual kiln reported by Ginsberg and Modigell (2011). The steady-state axial gas and solid temperature profiles have been also satisfactorily validated with the numerical results of the aforementioned paper. The output data consist of refractory wall temperature distribution, the axial solids and gas temperature profiles, axial solids composition profile, the length required for drying of the solid charge and the total kiln length required to achieve 98% conversion of anatase TiO 2 to rutile TiO 2 . A detailed parametric study with respect to the controlling parameters such as percent water content (with respect to dry solids), solids flow rate, gas flow rate, kiln inclination angle and kiln rotational speed lent a good physical insight into the rutile-TiO 2 production process in a rotary kiln. [ABSTRACT FROM AUTHOR]

Since the first outbreak of Middle East Respiratory Syndrome (MERS), Korea has a quite rapid MERS spread compared to other countries. Possible causes for such a sudden increase include the undiagnosed initial patient and lapses in infection control practices. To characterize MERS infection and transmission, this paper applies the period-based discrete SEIR model. Infected people of SEIR model shows a good fit to observed patients and MERS will become extinct around 113 days since the first outbreak. Through an effective quarantine plan, if we can reduce exposable people by 20%, it is estimated that the maximum number of infectious people may decrease by about 69% and MERS fade-out period will be shortened by about 30%. Simulations on assumed model support that Korean government's two policies to control MERS infection rate are effective in lessening its spread. Simulation on reproduction ratio scenarios in SEIR model indicates that success in early infection control practices is critical for shortening the period of disease fade-out. Even there are some restrictions and assumptions on SEIR model simulation, our simulation results are to be helpful in developing strategies to prevent the infectious diseases like MERS. [ABSTRACT FROM AUTHOR]

Copyright of Informatics in Education is the property of Informatics in Education and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Bayesian methods have seen an increase in popularity in a wide variety of scientific fields, including epidemiology. One of the main reasons for their widespread application is the power of the Markov chain Monte Carlo (MCMC) techniques generally used to fit these models. As a result, researchers often implicitly associate Bayesian models with MCMC estimation procedures. However, Bayesian models do not always require Markov-chain-based methods for parameter estimation. This is important, as MCMC estimation methods, while generally quite powerful, are complex and computationally expensive and suffer from convergence problems related to the manner in which they generate correlated samples used to estimate probability distributions for parameters of interest. In this issue of the Journal, Cole et al. (Am J Epidemiol. 2012;175(5):368–375) present an interesting paper that discusses non-Markov-chain-based approaches to fitting Bayesian models. These methods, though limited, can overcome some of the problems associated with MCMC techniques and promise to provide simpler approaches to fitting Bayesian models. Applied researchers will find these estimation approaches intuitively appealing and will gain a deeper understanding of Bayesian models through their use. However, readers should be aware that other non-Markov-chain-based methods are currently in active development and have been widely published in other fields. [ABSTRACT FROM AUTHOR]

This paper describes the research on adaptronic systems made by the author and offers to use biosensors that can be later inserted into the adaptronic systems. Adaptronic systems are based, on the one hand, on the adaptronic approach when the system is designed not to always meet the worst condition, but to change the structure of the system according to the external conditions. On the other hand, it is an extension of common automatic control ad adaptive systems. So, in the introduction firstly the adaptronic approach and biosensor as a term is explained. Adaptive systems, upon which adaptronic ones are based, are also mentioned. Then the construction of biosensor is described, as well as some information is given about the classification of biosensors and their main groups. Also it is suggested to use lichen indicators in industry to control concentration of chemical substances in the air. After that mathematical models and computer experiments for adaptronic system and biosensor analysis are given. [ABSTRACT FROM AUTHOR]

In this paper, the mechanical sensitivity of a vibration sensor is investigated by developing a mathematical model with the function of a relative movement modulus and measurement error. This model enables mechanical sensitivity to be improved by enhancing the performance of the vibration sensor. The purpose of the present work is to reduce measurement error by choosing the right damping rate that enables vibration sensor sensitivity to be optimized. The presented model is validated by computer simulation and experimental tests. The obtained results have shown that correct choice of damping rate and frequency range keeps the mechanical sensitivity constant. [ABSTRACT FROM PUBLISHER]

In this paper, the use of continuous mathematical models of an aircraft in an aircraft simulator is described. The models are of lower degree and less time-consuming for calculation. Computer implementation of the models capable to work faster and more accurately and efficiently is also described. The suggested approach allows to achieve the required precision at accelerated simulation speed using the continuous mathematical models of an aircraft. Frequency of the computation of continuous mathematical models of an aircraft is higher, reaching up to 200 times per second. The main focus of the paper is designing continuous mathematical models of an aircraft, their simulation and visualization in aircraft simulators. Current mathematical models of a control of objects motion are based on aircraft aerodynamics. In our approach, these models have impact on the quality and completeness of simulation process and are crucial for computer modeling and visualization of equations of the continuous mathematical models of an aircraft. In the paper, creating continuous mathematical models of an aircraft and the way of visualization of simulation results are described in detail. The main aim of computer simulation of continuous mathematical models of an aircraft is pilots training. Aircraft simulator plays a key role in the process of pilots training; it enables pilots to control the aircraft and its equipment. Standard computer with a graphic processing unit for the visualization results from continuous mathematical models of an aircraft can be utilized. [ABSTRACT FROM AUTHOR]

In this paper, a two-stage dispatching rule for the on-time delivery of an order-driven FAB is presented. Dispatching rules have a significant impact on the performance of FABs. Consequently, many such rules have been created, such as first in first out, earliest due data, operation due date, and critical ratio. Because these conventional dispatching rules make decisions only by considering the due date of each lot, they might not be suitable for dynamic order-driven FABs, for which it is very essential to monitor not only the due date of each lot but also the production rate of each step. In the first stage of the proposed two-stage dispatching rule, the production rate of each step is taken into account, and the due date of each lot is considered in the second stage. In this paper, the production rates of steps are computed by combining forward simulation and backward pegging. A simulation model, based on a wafer FAB data-set, has been developed, and simulation is conducted using commercial software SEEPLAN®. The simulation results clearly show the advantages of the proposed dispatching rule over existing rules. [ABSTRACT FROM PUBLISHER]

Laboratory-scale experimental studies have demonstrated that Chemical-Looping Combustion (CLC) is an advanced technology which holds great potential for high-efficiency low-cost carbon capture. The generated syngas in CLC is subsequently oxidized to CO2 and H2O by reaction with an oxygen carrier. In this paper, process-level models of CLC are established in ASPEN Plus code for detailed simulations. The entire CLC process, from the beginning of coal gasification to reduction and oxidation of the oxygen carrier is modeled. The heat content of each major component such as fuel and air reactors and air/flue gas heat exchangers is carefully examined. Large amount of energy is produced in the fuel reactor, but energy needs to be supplied to the air reactor. The overall performance and efficiency of the modeled CLC systems are also evaluated. [ABSTRACT FROM AUTHOR]

Computer simulations of complex food-webs are important tools for deepening our understanding of these systems. Yet most computer models assume, rather than generate, key system-level patterns, or use mathematical modeling approaches that make it difficult to fully account for nonlinear dynamics. In this paper, we present a computer simulation model that addresses these concerns by focusing on assumptions of agent attributes rather than agent outcomes. Our model utilizes the techniques of complex adaptive systems and agent-based modeling so that system level patterns of a marine ecosystem emerge from the interactions of thousands of individual computer agents. This methodology is validated by using this general simulation model to replicate fundamental properties of a marine ecosystem, including: (i) the predator-prey oscillations found in Lotka-Volterra; (ii) the stepped pattern of biomass accrual from resource enrichment; (iii) the Paradox of Enrichment; and (iv) Gause's Law. [ABSTRACT FROM AUTHOR]

'The problem with simulations is that they are doomed to succeed.' So runs a common criticism of simulations-that they can be used to 'prove' anything and are thus of little or no scientific value. While this particular objection represents a minority view, especially among those who work with simulations in a scientific context, it raises a difficult question: what standards should we use to differentiate a simulation that fails from one that succeeds? In this paper we build on a structural analysis of simulation developed in previous work to provide an evaluative account of the variety of ways in which simulations do fail. We expand the structural analysis in terms of the relationship between a simulation and its real-world target emphasizing the important role of aspects intended to correspond and also those specifically intended not to correspond to reality. The result is an outline both of the ways in which simulations can fail and the scientific importance of those various forms of failure. [ABSTRACT FROM AUTHOR]

In this paper, an accelerometer mathematical model is developed and simulated to choose the best damping rate value to limit the measurement error to 1%. Using this model, the equations of relative movement modulus and measurement error with respect to damping rate and frequency ratio can be determined. The developed model is validated by a series of tests carried out by computer simulation. The obtained results have shown that a suitable damping rate can minimize the measurement error of relative movement to 1 %. The presented model is a useful tool to improve the damping rate and measurement precision of the accelerometer. [ABSTRACT FROM PUBLISHER]

In this paper, the effects of nonlinear High Power Amplifier (HPA) with memory on Multi-Input Multi-Output (MIMO) Orthogonal Frequency Division Multiplexing (OFDM) system are analyzed and a theoretical framework is proposed. The memory effects are represented by Generalized Memory Polynomial (GMP) model. Moreover, we derive an analytical formulation with infinite nonlinearity order and infinite memory length. The channel is assumed MIMO frequency selective and it is modeled as a linear dispersive channel with uniform power profile. We show that the decision variables of the nonlinearity distortion can be modeled by the complex attenuation and zero mean additive noise model. The analytical expressions for complex attenuation, mean and variance of nonlinear noise are derived and SER of MIMO-OFDM system using HPA with memory is presented. Excellent agreement between the analytical results and numerical simulations is observed that verifies the accuracy and efficiency of the proposed method. [ABSTRACT FROM PUBLISHER]

This paper presents results of experimental and numerical modeling of ductile fracture and failure of elements made of S235JR steel subjected to static tension. The prediction of failure was generally based on the stress modified critical strain (SMCS) model. The numerical simulations were performed using the Gurson-Tvergaard-Needleman (GTN) model, which takes into consideration the material structure. The approach applied in this study was based on the computational cells with microstructurally based length scales. The cell size and initial porosity were determined through microstructural examinations of S235JR steel. The parameters of the GTN model for S235JR steel were established on the basis of the microstructural analysis and the numerical modeling of tensile strength tests. As a result, it was possible to determine the SMCS failure criterion to predict ductile fracture for S235JR steel. [ABSTRACT FROM AUTHOR]

Conducted disturbances induced into automotive electronic equipment can be predicted in the early design phase by numerical simulation. This supposes a realistic modeling of the cable harness, as well as the electronic equipment. This paper evaluates a modeling method by the results obtained on a realistic automotive subsystem. The latter is composed of two pieces of electronic equipment connected to each other by a cable harness. This test case was performed on printed circuit boards (PCBs) with full or partial ground planes and using a representative sample of harnesses. Simulation results are compared with measurement results using multiple cable harness samples. A good agreement between measurement and simulation can be obtained for PCBs with full ground plane, provided that fringing effects of the electronic components are taken into account in the equipment model. [ABSTRACT FROM AUTHOR]

The paper focuses on the design of a robust H-infinity attitude controller for an unmanned small-scale helicopter. To take into account the salient nonlinearities, a model with six-degrees-of-freedom nonlinear dynamics and some linear approximation of the aerodynamic parts are used when extracting a linear model and performing simulations to check the performance of the designed controller. To design a robust H-infinity controller, an augmented plant is constructed by adjusting several weighting functions. Then, a robust controller is synthesized utilizing the augmented system with the weighting functions and H-infinity control methodology. Using computer simulation it is shown that the H-infinity controller works well when applied to the nonlinear model even though it is designed using a linear model approximation. Through frequency response analysis, it is shown that the proposed controller can overcome more than half of the uncertainty variations around a nominal point at the input side. The time-domain simulation with the nonlinear model demonstrates that the proposed controller is very robust in relation to the uncertainties, as was expected, overcoming large gain uncertainties and time delay in each input channel. The analysis and simulation results also show that the control system satisfies the Level 1 handling requirements, as defined in Aeronautical Design Standard ADS-33E-PRF. [ABSTRACT FROM AUTHOR]

This paper presents a mathematical model of carbon nanotubes-based mediatorless biosensor. The developed model is based on nonlinear non-stationary reaction-diffusion equations. The model involves four layers (compartments): a layer of enzyme solution entrapped on a terylene membrane, a layer of the single walled carbon nanotubes deposited on a perforated membrane, and an outer diffusion layer. The biosensor response and sensitivity are investigated by changing the model parameters with a special emphasis on the mediatorless transfer of the electrons in the layer of the enzyme-loaded carbon nanotubes. The numerical simulation at transient and steady state conditions was carried out using the finite difference technique. The mathematical model and the numerical solution were validated by experimental data. The obtained agreement between the simulation results and the experimental data was admissible at different concentrations of the substrate. [ABSTRACT FROM AUTHOR]

Systems of technological networks (so-called Critical Infrastructures) might undergo strong perturbations leading to the reduction of their functionalities (crisis scenarios). Under perturbed conditions, infrastructures deliver their specific services in a range from a partial reduction up to a complete loss. Systems of complex technological networks (electrical, telecommunications, roads and railways, oil, gas and water pipelines etc.) are known to display large interdependences (a fault on one system spreads over the others); for this reason, it is relevant to devise simulators and decision support systems able to capture the complexity of such a "system of systems". The paper presents parts of the outcomes of a larger scientific project aiming at realizing a Decision Support System to predict the occurrence of undesired events and their consequences. In particular, we present a conceptual modeling approach consisting of a declarative language and a software implementation for the description and simulation of elements of Crisis Scenarios. The software application is conceived for risk managers, i.e. operators with a deep knowledge of critical infrastructure scenarios, but not necessarily with high-level IT or mathematical skill. [ABSTRACT FROM AUTHOR]

Teaching and Design Workbench (T&D-Bench) is a framework aimed at education and research in the areas of computer architecture and embedded systems. It includes a set of features not found in other educational environments. This set of features is the result of an original combination of design requirements for T&D-Bench: that the framework should provide modeling capabilities similar to that of Architecture Description Languages (popular in embedded systems design), and that it should have the simulation capabilities found only in educational simulators. This paper highlights the main features and the latest achievements of the framework and of its didactic and research simulators. The results of a new didactic strategy, supported by the simulators, are presented and discussed. The design of a new architectural feature for embedded processors, using a research simulator, is introduced, and it is shown how to employ such a research work as an educational module to teach the complexities involved in embedded systems design. [ABSTRACT FROM AUTHOR]

The modern approach of the exploration of dynamic characteristic of elements or system of some device has been enabled by system dynamics. System dynamics is an excellent software system for studying the dynamic of the behaviour of natural, technical and societal realities i.e. system of various natures and features in which there exist relatively high analogy rate. The methodology of its work, including even the use of digital computers has shown to be an efficient mean for solving the problems: management, behaviour, sensitivity, flexibility and studying of dynamics of the behaviour of the systems of high complexity by computer simulation, in laboratory what means without danger for the realities observed. For the usage of system dynamics in the solution of complex problems, various complex knowledge from various scientific disciplines are required, but good knowledge of the nature of the problem itself, which is being analyzed. The paper has analyzed dynamic characteristic of cooling system in marine diesel engines by means of system dynamics. The cooling system of propulsion of MDE is a complex system onto which various disorders act and due to their changeable act result into the changes of working temperature of MDE. System dynamic approach in the analysis of MDE enable us to obtain the answer to the question "What if…" in other words we arrive at the solution what the reaction would be at the changes of any variable in the cooling system. The paper has shown: dynamic and static regime of work, mathematic model of the cooling system of MDE, simulation model in POWERSIM programme language and diagrams of the flows of water. [ABSTRACT FROM AUTHOR]

In this paper the MADA mathematical model is presented for the optimal management of aquifer exploitation. The model is built by embedding the AQÜIMPE model for simulation of ground water aquifers into a linear programming algorithm. MADA is used to evaluate exploitation in «Cuenca Sur de la Habana» aquifer, following a given water use plan (PUA). It is shown in the paper that PUA distribution of well abstractions is not considering possible saline intrusion in the aquifer and to that end a solution is presented. [ABSTRACT FROM AUTHOR]

The dual-use of games in both military and entertainment applications has a long history. This has taken the form of sand tables, miniatures, board games, and computer games. The current tension between entertainment and military applications over games is just the return of similar concerns that have surrounded gaming tools and technologies in previous generations. Dynamic representations of the physical world are interesting and useful tools in a number of fields, to include the military, city planning, architecture, education, and entertainment. Modern computer games contain technologies and tools that allow many different communities to accomplish similar goals. [ABSTRACT FROM AUTHOR]

Computer simulations are an exciting tool that plays important roles in many scientific disciplines. This has attracted the attention of a number of philosophers of science. The main tenor in this literature is that computer simulations not only constitute interesting and powerful new science, but that they also raise a host of new philosophical issues. The protagonists in this debate claim no less than that simulations call into question our philosophical understanding of scientific ontology, the epistemology and semantics of models and theories, and the relation between experimentation and theorising, and submit that simulations demand a fundamentally new philosophy of science in many respects. The aim of this paper is to critically evaluate these claims. Our conclusion will be sober. We argue that these claims are overblown and that simulations, far from demanding a new metaphysics, epistemology, semantics and methodology, raise few if any new philosophical problems. The philosophical problems that do come up in connection with simulations are not specific to simulations and most of them are variants of problems that have been discussed in other contexts before. [ABSTRACT FROM AUTHOR]

This paper argues that a successful philosophical analysis of models and simulations must accommodate an account of mathematically rigorous results. Such rigorous results may be thought of as genuinely model-specific contributions, which can neither be deduced from fundamental theory nor inferred from empirical data. Rigorous results provide new indirect ways of assessing the success of models and simulations and are crucial to understanding the connections between different models. This is most obvious in cases where rigorous results map different models on to one another. Not only does this put constraints on the extent to which performance in specific empirical contexts may be regarded as the main touchstone of success in scientific modelling, it also allows for the transfer of warrant across different models. Mathematically rigorous results can thus come to be seen as not only strengthening the cohesion between scientific strategies of modelling and simulation, but also as offering new ways of indirect confirmation. [ABSTRACT FROM AUTHOR]

Event graphs model the dynamics of a discrete-event simulation model. This paper demonstrates the modeling power of event graphs by presenting a model that simulates a Turing machine. Therefore, according to Church's thesis, event-graph models are able to model any system that can be implemented on a modern computer. Theoretical and practical implications of this assertion are also discussed. [ABSTRACT FROM AUTHOR]

Network research generally requires a simulation or emulation environment to test protocol implementations, to evaluate the performance of a scheme or a system, and to study complicated and highly varying network operations. For large network simulation, simulators will consume a large amount of time and memory, and its result is largely based on some modeling assumptions that may not hold in the real world. Emulators are difficult to scale for large network emulation because of the high cost of equipment if a one-to-one mapping scheme is employed. Otherwise, the target network has to be abstracted to a single router modeled with some performance metrics. In this paper, we present a distributed IP network emulator cluster EMPOWER, which not only can be used to emulate a large network with a limited number of commodity computers, but also can generate user-defined arbitrary network conditions and traffic dynamics at packet level for specific test scenarios. EMPOWER is highly scalable in that each emulator node could be configured to emulate multiple network nodes, and the increment of the number of emulator nodes does not affect emulation validity. Some significant research issues such as network mapping and mobile wireless network emulation are discussed and addressed. Preliminary emulation results show that EMPOWER is capable of assisting the study of both wireline and wireless network protocols and applications. [ABSTRACT FROM AUTHOR]

This paper describes the measurement setup and modeling technique used for obtaining a linear wide band frequency-dependent black box model of a two-winding power transformer, for the purpose of calculation of electromagnetic transients in power systems. The measurement setup is based on a network analyzer, shielded cables, and a connection board. The setup is demonstrated to give a consistent data set where the effect of the measurement cables can be eliminated. The accuracy of the data set is increased by using a combination of current measurements and voltage transfer measurements. A rational approximation of the admittance matrix is calculated in the frequency domain in the range of 50 Hz to 1 MHz and subjected to passivity enforcement, giving a stable model which can be included in electromagnetic transients program (EMTP)-type simulation programs. The accuracy is validated both in the frequency domain and in the time domain. [ABSTRACT FROM AUTHOR]

This paper deals with simulation platform of optical transmission system in Matlab Simulink. A detailed mathematical methodology in order to accurately model parts of optical transmission system is presented. The simulation platform is suitable for simulation single channel optical transmission system. The selected approach takes into account noises that occurs on the parts of optical transmission system. [ABSTRACT FROM AUTHOR]

There are many techniques available for performance modeling of flexible manufacturing systems, including computer simulation and queuing models. This paper presents MAP/1, a simulation-based modeling and analysis program developed specifically for manufacturing systems. We begin with a short description of the MAP/1 program. This is followed by a discussion of special features available to support the modeling of flexible manufacturing systems. An example model illustrating these features is then presented. [ABSTRACT FROM AUTHOR]

Operational performance in residential construction production systems is assessed based on measures such as average house-completion time, number of houses under construction, lead time, and customer service. These systems, however, are prone to nonuniformity and interruptions caused by a wide range of variables such as inclement weather conditions, accidents at worksites, fluctuations in demand for houses, and rework. The availability and capacity of resources therefore are not the sole measures for evaluating construction production systems capacity, especially when rework is involved. The writers' aim is to investigate the effects of rework timeframe and frequency/length on tangible performance measures. Different call-back timeframes for rework and their impact on house-completion times are modeled and analyzed. Volume home-building was chosen as the industry sector studied in the research reported in this paper because it is a data-rich environment. The writers designed several experiments to model on time, late, and early call-back timeframes in the presence of rework with different length and frequency. Both mathematical modeling and discrete-event simulation were then used to compare and contrast outputs. The measurements showed that the average completion time is shorter in systems interrupted by frequent but short rework. In other words, a smaller downstream buffer between processes is required to avoid work starvation than those systems affected by infrequent but long interruptions. Early call-backs for rework can significantly increase the number of house completions over the long run. This indicates that there is an opportunity for the mass house-building sector to improve work practice and project delivery by effectively managing rework and its related variables. The research reported in this paper builds on the current body-of-knowledge by applying even-flow production theory to the analysis of rework in the residential construction sector, with the intention of ensuring minimal disruption to construction production process and improving productivity. [ABSTRACT FROM AUTHOR]

This paper presents numerical studies of large-size and high-quality fused silica glass synthesis by SiCl 4 flame hydrolysis deposition method, specifically the correlation of uniformities of SiO 2 deposition and OH concentration with the optimal location of the substrate placement. A comprehensive computational model is developed to describe the complex turbulent reacting flow with the detailed SiCl 4 -H 2 -O 2 reaction mechanism. Numerical simulation is first conducted to obtain the characteristics of SiCl 4 hydrolysis flame without considering the substrate and the SiO 2 particle formation. The distribution of SiO 2 accumulation is then calculated. The potential region and location for placing substrate are initially determined based on the criterion of a uniform SiO 2 accumulation. Further, the effects of H 2 -O 2 equivalence ratio and the SiCl 4 flow rate on the distributions of the temperature, SiO 2 concentration and OH concentration are investigated. It is found that the H 2 -O 2 equivalence ratio is sensitive to the temperature and the OH concentration, and the flow rate of SiCl 4 mainly affects the temperature and SiO 2 concentration. This finding indicates that the H 2 -O 2 equivalence ratio and the flow rate of SiCl 4 have equally important roles in determining the optimal location for the deposition substrate placement. The presence of the substrate also changes the distributions of the temperature and compositions concentrations in the furnace. Adjusting the substrate location is an effective strategy to achieve optimal location with more uniform distributions of the SiO 2 accumulation and the OH concentration on the deposition surface. [ABSTRACT FROM AUTHOR]

The main market studies depict a future in which all one-aisle aeroplanes will mount engines composed of elements with complex surfaces. Among the new generation of tools, the barrel-shaped tools were released to the market for the machining of such types of surfaces. However, there are no evidences reported in the literature about how do these tools work. This work presents for the first time a mathematical model based on the numerical discretization of barrel cutters to predict the cutting forces. The effects of helix angle, runout and lead and tilt angles were included and the model was validated for a range of conditions in a 5-axis machine. In this line, this paper enables future mathematical developments including more details and aiming at other complex problems. [ABSTRACT FROM AUTHOR]

Agent-based simulation modelling has been used in many epidemiological studies on infectious diseases. However, because agent based modelling is a field without any clear protocol for developing simulations the researcher is given a high amount of flexibility. This flexibility has led to many different forms of agent-based epidemiological simulations. In this paper we review the existing literature on agent-based epidemiological simulation models. From our literature review we identify key similarities and differences in the existing simulations. We then use these similarities and differences to create a taxonomy of agent-based epidemiological models and show how the taxonomy can be used. [ABSTRACT FROM AUTHOR]

Modern passenger terminals are characterized by dynamic processes variability, diverse options consideration, taking into account the criteria of safety, reliability analysis and the continuous research of passenger processing. For any modern marine passenger terminal it is necessary to use the tool to simulate passenger flows. In this way it is possible to obtain the analytical information and use it for decision-making when solving the problem of the amount of personnel required for passenger services.in line with the original ship arrival schedule, to solve problems of forecasting groups at the terminal. Of particular relevance is the choice of the mathematical transport model and the practical conditions for the implementation of the model in the real terminal operation. In this article the analysis technique of simulation-based terminal services, provides a mathematical model of passenger movement inside the terminal. Also, the conditions of implementation of the transportation model during the operation of marine passenger terminal are examined. The object of the research is the marine Passenger Port of St. Petersburg “Marine Facade”. The paper discusses advantages of using such systems and their introduction in the early stages of operation of the terminal. In addition, the conclusion about the effectiveness of such systems for the analysis of the correctness of internal space of the marine terminal. The study represents an example of analytical information used for the forecast of the terminal operations, the analysis of the workload and efficiency of the organization of the marine terminal. [ABSTRACT FROM AUTHOR]