SIMULTECH 2012 Abstracts


Area 1 - Simulation Tools and Platforms

Full Papers
Paper Nr: 17
Title:

Rate-based Simulation of Coke Calcination in Rotary Kilns

Authors:

E. M. Elkanzi, F. S. Marhoon and M. J. Jasim

Abstract: This paper presents the simulation of the green petroleum coke calcining processes using the simulation program ASPEN HYSYS. The results are validated using actual industrial data. The present study provides a detailed description of the rate-based simulation. It considers the rate of physical and chemical phenomena of interest: the rate of moisture removal, the rate of volatile matter release and combustion, and the rate of coke dust and sulfur combustion. Data supplied by a local coke calcining kiln in operation are used to validate the simulation results. It is found that the rate-based simulation can be implemented as a useful tool to predict the operating conditions needed to control the content of undesirable impurities in the calcined petroleum coke, namely, sulfur, volatile matter and moisture contents. Except for the metal content, the simulation shows that it is possible for the kiln operator to process any type of green coke for varying sulfur, volatile matter and water contents by adjusting the amount of tertiary air and/or fuel.

Paper Nr: 18
Title:

Mechatronic System Optimization based on Surrogate Models - Application to an Electric Vehicle

Authors:

Moncef Hammadi, Jean-Yves Choley, Olivia Penas and Alain Riviere

Abstract: Preliminary optimization of mechatronic systems is an extremely important step in the development process of multi-disciplinary products. However, long computing time in optimization based on multi-domain modelling tools need to be reduced. Surrogate model technique comes up as a solution for decreasing time computing in multi-disciplinary optimization. In this paper, an electric vehicle has been optimized by combining Modelica modelling language with surrogate model technique. Modelica has been used to model the electric vehicle and surrogate model technique has been used to optimize the electric motor and the transmission gear ratio. Results show that combining surrogate model technique with Modelica reduces significantly computing time without much decrease in accuracy.

Paper Nr: 19
Title:

Elastomeric Seismic Isolators Behavior at Different Pads Thickness

Authors:

Gabriele Milani and Federico Milani

Abstract: A seismic isolator has the main function to be extremely deformable for horizontal forces, but at same time sufficiently stiff when loaded with vertical actions. These properties may be strongly influenced by both the isolator geometry (i.e. overall dimensions, number and thickness of rubber pads and steel laminas) and the mechanical properties of rubber pads. Mechanical properties of the pads, especially Young modulus, may be evaluated as a function of hardness, by means of consolidated empirical formulas. In this work, the influence of rubber pads thickness and hardness on both vertical and horizontal stiffness of realistic seismic isolators is discussed. Three full 3D Finite Element models referred to three different seismic isolators having different slenderness are analysed in detail in both vertical compression (elastic analysis) and simple shear in large deformations. Uniaxial and shear response of the seismic devices obtained numerically are finally critically compared, with the aim of evaluating the best compound to be used in practice.

Paper Nr: 25
Title:

Simulation of Shallow-water Flows in Complex Bay-like Domains

Authors:

Yuri N. Skiba and Denis M. Filatov

Abstract: A new numerical method for the simulation of shallow-water flows in a bay-like domain is suggested. The method is based on the splitting of the original nonlinear operator by physical processes and by coordinates. An essential advantage of our finite difference splitting-based method versus others in the field is that it leads to a model allowing accurate simulation of shallow-water flows in a domain of an arbitrary shape with both closed and open boundaries, which besides may contain onshore parts inside (interior isles in the bay); the model also takes into account irregular bottom topography. Specially constructed approximations of the temporal and spatial derivatives result in second-order unconditionally stable finite difference schemes that conserve the mass and the total energy of the discrete inviscid unforced shallow-water system. Moreover, the potential enstrophy results to be bounded, oscillating in time within a narrow range. Therefore, the numerical solution, aside from being accurate from the mathematical point of view, appears to be physically adequate, inheriting a number of substantial properties of the original differential shallow-water system. Furthermore, the method can straightforwardly be implemented for distributed simulation of shallow-water flows on high-performance parallel computers. To test the method numerically, we start with the inviscid shallow-water model and verify the conservatism of the schemes in a simple computational domain. Then we introduce a domain with a more complex boundary consisting of closed and open segments, and consider more realistic viscous wind-driven shallow-water flows. Numerical experiments presented confirm the skills of the developed method.

Paper Nr: 46
Title:

Observations of Discrete Event Models

Authors:

Gauthier Quesnel, Ronan Trépos and Éric Ramat

Abstract: The observation of a simulation is an important task of the modeling and simulation activity. However, this task is rarely explained in the underlying formalism or simulator. Observation consists to capture the state of the model during the simulation. Observation helps understand the behavior of the studied model and allows improving, analyzing or debugging it. In this paper, we focus on appending an observation mechanism in the Parallel Discrete Event System Specification (PDEVS) formalism with guarantee of the reproducible simulation with or without observation mechanism. This extension to PDEVS allows us to observe models at the end of the simulation or according to a time step. Thus, we define a formal specification of this extension and its abstract simulators algorithms. Finally, we present an implementation in the DEVS framework VLE.

Paper Nr: 57
Title:

A Simple Efficient Technique to Adjust Time Step Size in a Stochastic Discrete Time Agent-based Simulation

Authors:

Chia-Tung Kuo, Da-Wei Wang and Tsan-sheng Hsu

Abstract: This paper presents a conceptually simple approach on adjusting the time step size in a stochastic discrete time agent-based simulation and demonstrates how this could be done in practical implementation. The choice of time step size in such a system is often based on the nature of the phenomenon to be modelled and the tolerated simulation time. A finer time scale may be desired upon the introduction of new events which could possibly change the system state in smaller time intervals. Our approach divides each original time step into any integral number of equally spaced sub-steps based on simple assumptions, and thus allows a simulation system to incorporate such events and produce results with finer time scale. Regarding the tradeoff between finer scale and higher use of resource, our approach also highlights the implementation techniques that increase the resource usage and simulation time only marginally. We analyze the results of this refinement on a stochastic simulation model for epidemic spread and compare the results with the original system without refinement.

Paper Nr: 81
Title:

A Model-driven Approach to Build HLA-based Distributed Simulations from SysML Models

Authors:

Paolo Bocciarelli, Andrea D'Ambrogio and Gabriele Fabiani

Abstract: The analysis and design of complex systems, which very often are composed of several sub-systems, takes advantages by the use of distributed simulation techniques. Unfortunately, the development of distributed simulation systems requires a significant expertise and a considerable effort for the inherent complexity of available standards, such as HLA. This paper introduces a model-driven approach to support the automated generation of HLA-based distributed simulations starting from system descriptions specified by use of SysML (Systems Modeling Language), the UML-based general purpose modeling language for systems engineering. The proposed approach is founded on the use of model transformation techniques and relies on standards introduced by the Model Driven Architecture (MDA). The method exploits several UML models that embody the details required to support two transformations that automatically map the source SysML model into a HLA-specific model and then use the latter to generate the Java/HLA source code. To this purpose, this paper also introduces two UML profiles, used to annotate UML diagrams in order both to represent HLA-based details and to support the automated generation of the HLA-based simulation code.

Paper Nr: 92
Title:

A Simulation-based Scheduling Strategy for Scientific Workflows

Authors:

Sergio Hernández, Javier Fabra, Pedro Álvarez and Joaquín Ezpeleta

Abstract: Grid computing infrastructures have recently come up as computing environments able to manage heterogeneous and geographically distributed resources, being very suitable for the deployment and execution of scientific workflows. An emerging topic in this discipline is the improvement of the scheduling process and the overall execution requirements by means of simulation environments. In this work, a simulation component based on realistic workload usage is presented and integrated into a framework for the flexible deployment of scientific workflows in Grid environments. This framework allows researchers to simultaneously work with different and heterogeneous Grid middlewares in a transparent way and also provides a high level of abstraction when developing their workflows. The approach presented here allows to model and simulate different computing infrastructures, helping in the scheduling process and improving the deployment and execution requirements in terms of performance, resource usage, cost, etc. As a use case, the Inspiral analysis workflow is executed on two different computing infrastructures, reducing the overall execution cost.

Paper Nr: 98
Title:

SimCore: A Library for Rapid Development of Large Scale Parallel Simulations

Authors:

Sunil Thulasidasan, Lukas Kroc and Stephan Eidenbenz

Abstract: We present the SimCore parallel simulation library, an object-oriented framework for developing parallel distributed discrete-event simulation applications, implemented in C++ with a Python front-end. SimCore is designed to scale to thousands of processors but is simple enough to use for application programmers, an outcome of its fast C++ core and message passing routines integrated with the full expressive power of Python. We discuss the design philosophy of SimCore including the software architecture and the C++/Python interface implementation that allows applications to be written in pure Python or a hybrid of Python and C++ or even pure C++. We also provide real world examples of the scalability and briefly describe a few diverse applications that have been deployed using SimCore.

Short Papers
Paper Nr: 23
Title:

Simulation and Multi-Objective Optimization of Vaccuum Ethanol Fermentation

Authors:

Jules Thibault, Rubens Maciel Filho, Marina O. S. Dias, Tassia L. Junqueira, Otavio Cavalett, Charles D. F. Jesus, Carlos E. V. Rossell and Antonio Bonomi

Abstract: With the overall objective of optimizing an integrated first and second generation bioethanol production plant, a simple illustrative example is first used to examine the advantages and challenges of using a combination of VBA and UniSim Design for multi-objective optimization. In this paper, the simulation and optimization of a vacuum fermentation system using glucose and xylose as substrates is performed. The simulation of the fermentation system and the optimization are performed in the VBA environment, while UniSim Design is used to provide thermodynamic data necessary to perform calculations and used to simulate the downstream portion of the fermentation vacuum system. The Pareto domain of the system was circumscribed based on three decision variables (starting time of vacuum, rate of broth removal by vacuum and condenser temperature) and four objective functions (minimum ethanol loss, maximum productivity, minimum residual sugars and minimum compression energy). The procedure developed has allowed to easily circumscribe the Pareto domain of this system and to observe clearly the compromises that are required when all objective functions are optimized simultaneously. Some challenges to overcome are the time required for exchanging information between VBA and UniSim Design and the risk of non-converging for complex problems. For this procedure to be implemented effectively for the integrated ethanol plant, some innovative measures need to be developed.

Paper Nr: 24
Title:

Process-oriented Discrete-event Simulation in Java with Continuations - Quantitative Performance Evaluation

Authors:

Antonio Cuomo, Massimiliano Rak and Umberto Villano

Abstract: In discrete-event simulation the process interaction view is appreciated in many different contexts, as it often provides the cleanest and simplest way to express models. However, this view is harder to implement than the more common event-oriented view. This is mostly due to the need for the simulation engine to support in a efficient way the coroutine-like semantics needed to implement the simulation processes. A common solution adopted in many Java-based simulators is the use of system threads to provide coroutines. This paper shows that this choice leads to unnecessary overheads and limitations, and presents an alternative implementation based on continuations. For many common models the continuation-based simulator shows significant performance gains compared to the most popular open source Java engines.

Paper Nr: 51
Title:

A Really Simple Explanation of Policy Punctuations? - Interdependence, Complexity, and Policy Punctuations

Authors:

Florian Prange and Søren Serritzlew

Abstract: We know for a fact that changes in budgets follow a leptokurtic or power law distribution. We have solid evidence that the degree of leptokurtosis can be explained by factors such as special features of policy areas, information processing, decision costs, and differences in the institutional setting (Jones & Baumgartner, 2005a; 2005b, Breunig, 2007; Jones, Sulkin and Larsen, 2003; Breunig and Koski, 2006). However, we do not know why leptokurtosis is omnipresent. In this paper we conjecture that leptokurtosis can be explained by four simple observations which must be true of any budgeting process: (1) that several actors request and spend budgets, (2) several actors allocate funding, (3) that actors which do not receive sufficient funding will eventually close down, and (4) that available funding is limited and often smaller than requested funding. We first review the literature on policy punctuations and leptokurtosis, and identify the four simple observations. We then discuss how a simulation can be useful in investigating the implications of these four observations, and introduce a simulation of the interaction of beggars and philanthropists in a budget game. We show that the four observations can account for the omnipresence of leptokurtosis at the sub system level. They cannot, however, explain the magnitude of leptokurtosis found in empirical distributions of budget changes.

Paper Nr: 52
Title:

A Framework to Provide Real Time Useful Knowledge in E-Learning Environments

Authors:

Àngela Nebot, Francisco Mugica and Félix Castro

Abstract: This research presents a framework that provides valuable knowledge to teachers and students, mainly based on fuzzy logic methodologies. The framework offers the following knowledge: 1) gives a sets of rules describing the students’ learning behaviour; 2) provides a relative assessment of the features involved in the students’ evaluation performance, i.e. detects and assess the most important topics involved in the course evaluation process; 3) groups the learning behaviour of the students involved in online courses, in an incremental and dynamical way, with the ultimate goal to timely detect failing students, and properly provide them with a suitable and actionable feedback. In this paper the proposed framework is applied to the Didactic Planning course of Centre of Studies in Communication and Educational Technologies virtual campus. The application shows it usefulness, improving the course understanding and providing valuable knowledge to teachers about the course performance.

Paper Nr: 54
Title:

Modelling Passengers Flow at Airport Terminals - Individual Agent Decision Model for Stochastic Passenger Behaviour

Authors:

Wenbo Ma, Clinton Fookes, Tristan Kleinschmidt and Prasad Yarlagadda

Abstract: Airport system is complex. Passenger dynamics within it appear to be complicate as well. Passenger behaviours outside standard processes are regarded more significant in terms of public hazard and service rate issues. In this paper, we devised an individual agent decision model to simulate stochastic passenger behaviour in airport departure terminal. Bayesian networks are implemented into the decision making model to infer the probabilities that passengers choose to use any in-airport facilities. We aim to understand dynamics of the discretionary activities of passengers.

Paper Nr: 56
Title:

Reusing Simulation Models for Weapons Effectiveness Analysis

Authors:

Kangsun Lee and Taesup Kim

Abstract: Simulation-based weapons effectiveness analysis involves complex modeling tasks to represent weapons, natural environment and operational environment. An integrated M&S (Modeling and Simulation) environment provides useful tools and services to partly automate the modeling tasks. Along with the M&S environment, a model repository can help model developers to ease the required tasks by sharing predefined and already validated models, generated from inside and outside the M&S environment. In this paper, we introduce our M&S environment, OpenSIM (Open Simulation Engine for Interoperable Models), and illustrate how the model repository in OpenSIM can enable users to reuse models for weapons effectiveness analysis. OpenSIM manages weapon ontology and thesaurus dictionaries to assess structural and contextual similarity between weapon models. We present semantic information and similarity measures of OpenSIM and illustrate how the model repository of OpenSIM helps users locate reusable weapon models.

Paper Nr: 77
Title:

Estimating Real Process Derivatives in on-Line Optimization - A Review

Authors:

M. Mansour

Abstract: The solution of the Integrated System Optimization and Parameter Estimation (ISOPE) problem necessitates the calculus of real process output derivatives with respect to the inputs. This information is needed in order to satisfy first and second order optimality conditions. Several methods exist and have been developed for calculating these derivatives. In this paper a review of most of the existing methods is presented, in which the Finite Difference Approximation, Dual Control Optimization, Broydon’s method, Dynamic Model Identification, with both linear and nonlinear models, together with a neural networks scheme are presented and applied, under simulation, to a cascade Continuous Stirred Tank Reactor (CSTR) system. The results are then discussed and compared to identify the advantages and disadvantages of using each method.

Paper Nr: 79
Title:

Automatic Design Optimisation of Pharmaceutical Tablets using PDEs

Authors:

Norhayati Ahmat, Gabriela González Castro and Hassan Ugail

Abstract: Pharmaceutical tablets and capsules are the dominant forms for drug delivery. Both types of dosage forms need to be strong enough to handle different types of stress due to packaging and loading conditions before use. Hence, it is important to produce these pharmaceutical forms with maximum mechanical strength while conserving the properties of their active ingredients during the design process. The present work describes a methodology for parametric design and optimisation of a solid cylindrical tablet and a soft spherical capsule, which is based on the use of Partial Differential Equations (PDEs). The PDE-based formulation is capable of parameterising complex shapes using the information at some boundary curves that describe the shape. It is shown that the optimal designs of both tablet and capsule can be obtained using an automatic design optimisation which is performed by combining the PDE method and a standard method for numerical optimisation.

Paper Nr: 80
Title:

A Structuring Mechanism for Embedded Control Systems using Co-modelling and Co-simulation

Authors:

Xiaochen Zhang and Jan F. Broenink

Abstract: In most embedded control system (ECS) designs, multiple engineering disciplines and various domain-specific models are involved, such as embedded software models in discrete-event (DE) domain and dynamic plant model in continuous-time (CT) domain. In this paper, we advocate collaborative modelling and co-simulation to verify different aspects of the system as a whole before implementation. This paper proposes a development approach and structuring mechanism for CT-intensive ECS designs using co-modelling and co-simulation techniques. Based on this approach, an integrated co-model can be developed and refined using different domain-specific languages and tools. Influences from one domain to the other can be simulated via cosimulation and analysed in both perspectives. Our structuring and development process has been applied to a mobile robot using this co-simulation technique. We have experienced that structuring the co-modelling process allows us to produce co-models an co-simulations effectively. Future work is on checking for model inconsistencies during collaboration, and provide approaches to deal with this.

Paper Nr: 86
Title:

Enhancing the Performances of D-MASON - A Motivating Example

Authors:

Michele Carillo, Gennaro Cordasco, Rosario De Chiara, Francesco Raia, Vittorio Scarano and Flavio Serrapica

Abstract: Agent-based simulation models are an increasingly popular tool for research and management in many, different and diverse fields. In executing such simulations the “speed” is one of the most general and important issues and the traditional answer to this issue is to invest resources in deploying a dedicated installation of dedicated computers, with highly specialized parallel applications, devoted to the purpose of achieving extreme computational performances. In this paper we present our experience with a distributed framework, D-MASON, that is a distributed version of MASON, a well-known and popular library for writing and running Agent-based simulations. D-MASON introduces the parallelization at framework level so that scientists that use the framework (domain expert but with limited knowledge of distributed programming) can be only minimally aware of such distribution. The framework allowed only a static decomposition of the work among workers, and was not able to cope with load unbalance among them, therefore incurring in serious performance degradation where, for example, many of the agents were concentrate on one specific part of the space. We elaborated two strategies for ameliorate the balancing and enhance the synchronization among workers. We present their design principles and the experimental tests that validate our approach.

Paper Nr: 93
Title:

A Model for Simulation of Application and Resource Behavior in Heterogeneous Distributed Computing Environments

Authors:

Per-Olov Östberg

Abstract: Accurate modeling of the behavior of resources and scientific applications in distributed computing environments is complicated by factors such as resource heterogeneity, variability, and volatility. In this work we present a simulation model for fine-grained simulation and analysis of resource environments composed by multiple types of distributed computing resources. The simulation model is based on simulation of individual computational resources and emulation of virtual infrastructures and resource environments. Application and resource behavior are modeled in behavior profiles that capture the wide variability of distributed computing applications and resources, and allow modeling of non-standard metrics such as heterogeneity, variability, and volatility of resources and resource environments. Around the behavior profiles, virtual infrastructures are emulated using discrete-event simulations where infrastructure components are independently modeled. The design of the framework is aimed to facilitate both verification of middleware and application software as well as experimentation with prototype infrastructure components.

Paper Nr: 94
Title:

A Meta-Model for DEVS - Designed following Model Driven Engineering Specifications

Authors:

Stéphane Garredu, Evelyne Vittori, Jean-François Santucci and Paul-Antoine Bisgambiglia

Abstract: In this paper we give a state-of-art of DEVS components interoperability, and we propose a meta-model for classic DEVS formalism, designed following a Model-Driven Engineering philosophy. After glancing at the existing related works, we explain in a step-by-step way how our meta-model is built, starting from the formal definition of DEVS formalism. As the hardest steps when defining a DEVS Platform-Independent Model (PIM) are the definition of the states and the definition of the DEVS functions, we particularly focus on those concepts and we propose a way to describe them in a simple and platform-independent way. UML class diagrams were chosen to represent this meta-model. Not only can this meta-model be useful to generate DEVS PIMs but it can also be seen as a powerful tool to improve interoperability between DEVS models (and in a larger way discrete-event models, via model-to-model transformations) and to provide automatic code generation towards DEVS simulators (model-to-text transformations). As this meta-model is not a final version but rather a starting point, we tried to make it as modular and upgradable as possible.

Paper Nr: 104
Title:

OPN-Ont: Object Petri Nets Ontology Tool

Authors:

Lynda Dib and Fouad Bousetouane

Abstract: Ontologies are being used nowadays in many areas, including software engineering, business, and biology, to evaluate their suitability for representing and simulating domain processes. To assist users in developing and maintaining ontologies a number of tools have been developed. The representation of knowledge bases and conceptual domain models, hierarchical process, the structural components that participate in the process and the roles that they play in a complex domain, is therefore a major challenge for computer scientists for this complex domain. Without aiming at exhaustiveness, our study combining ontology and Petri Nets (PNs) tries to identify some promising tracks in this area, which seems a rather interesting alternative in the optics of the expressive power of the deductive representations. The context of our work consists to develop a graphical knowledge model for complex domain. This paper presents the OPN-Ont (Object Petri Nets Ontology) model. In this system ontology is represented in the PNs format, which allows verification of formal properties and qualitative and quantitative simulation. It leads to represent and exploit the different ontological components: concepts, relations and requests. The illustration of our model is made in biological domain where process supports methods for qualitative and quantitative reasoning.

Paper Nr: 110
Title:

Simulation of Protection Mechanisms against Botnets on the Basis of “Nervous Network” Framework

Authors:

Igor Kotenko and Andrey Shorov

Abstract: The paper suggests a simulation approach to investigate the protection against botnets on the basis of the “nervous network” framework. This approach is an example of bio-inspired approaches to the computer networks protection. The developed simulator is described. Results of the experiments are considered. Finally, we analyze and compare the performance of the basic protection mechanisms with “nervous network” protection technique.

Posters
Paper Nr: 14
Title:

An Approach to Implementation of Physical Simulation Models

Authors:

Shpakov Vladimir

Abstract: Advantages of a rule-based approach to dynamic system physical models specification and implementation are discussed. Much need for the approach at the modern state of system engineering is pointed out. In particular, such an approach may be useful for simulation of control and self-organizing systems. A rule-based situation formalism of an interacting hybrid processes specification is briefly stated and some ways of its use for physical simulation model implementation are shown. Facilities of the considered methods are illustrated by examples of some simple dynamic system models implementations. Specifications of these physical models and some results of simulation are presented.

Paper Nr: 27
Title:

Simulative Model and Multicriteria Optimization of Truss Beam in Super-Large Columns at High Temperature

Authors:

Yanzhen Liu, Hong Gao and Jinsheng Sun

Abstract: With the increasingly enlarged process scale and the consequent requirement for large equipment, such as column, trusses ever widely applied in civil and building engineering have been introduced in petroleum chemical industry these years. Under this circumstance, truss structure optimization emerges as a study focus to balance safety, durability and economy. In this paper, an optimization example is introduced of a main truss beam system, namely centre, and its side beams in super-large column at high temperature. The main truss beam is optimized on three counts, that is, cross-section shape of the chord members, structure height and the pairs of the web members, while side beams are optimized by compromising among workability, stress, stiffness and weight.

Paper Nr: 67
Title:

Simulation of Real-time Data Grid Systems via DGridSim Simulator

Authors:

Safai Tandoğan, Mustafa Müjdat Atanak and Atakan Doğan

Abstract: In this study, DGridSim simulator will be introduced and some example simulation results will be presented. DGridSim can simulate four different Data Grid system organizations. Furthermore, for every system organization, the simulation of job scheduling, data dissemination, and data replication algorithms are supported, while all related system resources including computing, data storage, and network are reserved in advance in order to meet deadlines associated with jobs. DGridSim simulator is designed to be modular and easily extensible.

Paper Nr: 74
Title:

RECORD - An Integrated Platform for Agro-ecosystems Study

Authors:

Ronan Trépos, Hélène Raynal and Gauthier Quesnel

Abstract: The complexity of models developped in order to improve the agricultural systems and the need to have efficient tools to build them, simulate and analyse them have motivated the conception and the development of the new modelling and simulating platform RECORD. This paper describes how this initiative of the French National Institute for Agricultural Research has been conducted. A pragmatic strategy consisting in integrating heterogeneous tools into a same framework has been used. The example of the integration of the 3 different tools: VLE, R, Python illustrates how the users’ requirements have been fullfilled. The platform is currently used in various projects, and on the basis of the first experiences, we conclude on the interest of this strategy. We underline that this strategy must be accompanied by efforts on developping user’s training and coaching on these powerful tools. Finally software design should facilitate collaborative developments, which will motivate our future works.

Paper Nr: 90
Title:

A General Process for Developing Business Simulations Games

Authors:

Claudia Ribeiro, José Borbinha, João Pereira and José Tribolet

Abstract: Nowadays people, groups and organizations are increasingly confronted with problems and situations that show an increasing level of complexity. However, human abilities to deal with complex dynamic systems and processes, while behaving in a sustainable way, have not improved to the required extent. One way to deal with complex situation is the simulation approach: build a simplified model of this reality, learn from this simplified model, and, finally, translate the findings or knowledge back to reality. Simulation games are based on this idea. Nevertheless, if we want to make inferences about reality based on experiences and knowledge acquired in a simulation game, we have to be sure that the underlying conceptual model is a good, or valid, representation of the real situation. Based on knowledge gather from the simulation development process and Agent-based Modelling, this paper proposes a general process for developing business simulation games.

Area 2 - Formal Methods

Full Papers
Paper Nr: 30
Title:

Sigmapoint Approach for Robust Optimization of Nonlinear Dynamic Systems

Authors:

Sebastian Recker, Peter Kühl, Moritz Diehl and Hans Georg Bock

Abstract: Mathematical models describing dynamic processes contain parametric uncertainties. Robust model-based optimization thus becomes a challenging task in process engineering. Current approaches either require high computational effort or they make use of oversimplified approximations that do not capture changes in the solution structure due to nonlinear effects of the uncertain parameters on the states of the process. In this paper we propose an improved optimization approach that uses sigmapoints to characterize the space of uncertain parameters. Propagating sigmapoints through the process model and directly using them in the optimization problem allows to capture relevant nonlinearities for the uncertain parameters. Main advantages of this simple yet elegant approach are the relatively low computational burden and the independence from the optimizer, as no further derivatives are needed. The approach is applied to two examples from process engineering, a batch distillation and a semibatch reactor.

Paper Nr: 45
Title:

A Simulation Study of Learning a Structure - Mike’s Bike Commuting

Authors:

Mamoru Kaneko, Jeffrey J. Kline, Eizo Akiyama and Ryuichiro Ishikawa

Abstract: This paper undertakes a simulation study of a player’s learning about the structure of a game situation. In a simple 1-person example called Mike’s Bike Commuting, we simulate the process in which Mike experiences and accumulates memories about the structure of Mike’s town. It is the basic requirement that to keep an experience as a long-term memory, Mike needs enough repetitions of that experience. By the choice of our simple and casual example, we can discuss relevant time spans for learning. The limit case of Mike’s learning as time tends to infinity is of little relevance to the problem of learning. We find that the concept of “marking” introduced by Kaneko-Kline is important for obtaining sufficient structural knowledge in a reasonable time span. Our study shows that Mike’s learning can change drastically with the concept. We also consider Mike’s learning about his preferences from his experiences, where we meet various new conceptual problems.

Paper Nr: 88
Title:

A Geometrical Refinement of Shape Calculus Enabling Direct Simulation

Authors:

Federico Buti, Flavio Corradini, Emanuela Merelli and Luca Tesei

Abstract: The Shape Calculus is a bio-inspired timed and spatial calculus for describing 3D geometrical shapes moving in a space. Its purpose is twofold: i) modelling and formally verifying (not only) biological systems, and ii) simulating the models for validation and hypothesis testing. The original geometric primitives of the calculus are highly abstract: the associated simulator needs to attach a lot of code to the model specification in order to perform an effective simulation. In this work we propose a calculus refinement in which a detailed 3D characterization of the geometric primitives is injected into the syntax of the calculus. In this way, models written with the new syntax can be directly simulated.

Posters
Paper Nr: 63
Title:

Simulation of the Thermal Management of the Semiconductor Disk Laser

Authors:

Yanrong Song, ZhenHua Yu, Peng Zhang and Zili Li

Abstract: For the optically pumped semiconductor disk lasers, the thermal problem is the key to obtain the high out power. To solve this problem, we simulated the heat distribution of the gain chip by finite-element analysis method to discover the heat spread affected by the thickness of the substrate and found the outstanding heat spread result of the diamond chip.

Paper Nr: 85
Title:

The Application of Evolutionary Algorithm for the Linear Dynamic System Modelling

Authors:

Ivan Ryzhikov and Eugene Semenkin

Abstract: The approach to dynamic system modelling in the linear differential equations form is presented. The given approach fits the identification problems with the system output observations sample and the input sample even if the output data is distorted by a noise. The structure and parameters identification problem is reduced to a global optimization problem, so that every solution consists of the model structure and its parameters. This allows searching the analytical model in the ordinary differential equation form with any limited order. The analytical model delivers a special benefit in its further use in the control and behaviour estimation problem.

Area 3 - Complex Systems Modeling and Simulation

Full Papers
Paper Nr: 62
Title:

Direct Numerical Simulation of Flow Past a Sphere in a Plane Turbulent Boundary Layer with Immersed Boundary Method

Authors:

Hui Zhao, Anyang Wei, Kun Luo and Jianren Fan

Abstract: Direct Numerical Simulation coupled with Immersed Boundary Method (IBM) has attracted wide atten¬tion recent years, making this technique a significant role in many practical engineering areas. This paper described a direct numerical study of flow past a sphere above a plane, which can obtain detail infor¬mation of flow field and vortex structure. A combined multiple-direct forcing and immersed boundary method (MDF/IBM) was used to deal with the coupling between fluid and solid. The Reynolds number based on sphere diameter was 4171. Behaviours of the vortices were observed through the simulation. The velocity distribution switched from laminar boundary to turbulent boundary. A recirculation region was observed behind the sphere. The influence of the sphere on the boundary layer, the center peak defect, the turbulence intensity and the Reynolds stresses are explored.

Paper Nr: 69
Title:

Airflow and Particle Deposition in a Dry Powder Inhaler - A CFD Simulation

Authors:

J. Milenkovic, A. H. Alexopoulos and C. Kiparissides

Abstract: In this work the steady-state flow in a commercial dry powder inhaler device (i.e., Turbuhaler) is described. The DPI geometry is constructed in a CAD/CAM environment (i.e., CATIA v5) and then imported into GAMBIT where the geometry is discretized into a computational grid. The Navier-Stokes equations are solved using FLUENT (v6.3) considering different flow models, i.e., laminar, k-ε, k-ε RNG, and k-ω SST. Particle motion and deposition are described using an Eulerian-fluid/Lagrangian-particle approach. Flow and particle deposition for a range of mouthpiece pressure drops (i.e., 800-8800Pa), as well as particle sizes corresponding to single particles and aggregates (i.e., 0.5-20μm) are examined. The total volumetric outflow rate, the overall particle deposition as well as the particle deposition sites in the DPI are determined. The transitional k-ω SST model for turbulent flow was found to produce results most similar to a reference Large Eddy Simulation solution as well as experimental results for the pressure drop in the DPI. Realistic particle deposition results could only be obtained by considering a nonideal sticking coefficient corresponding to a critical capture velocity of 2.7m/s. Overall, the simulation results are found to agree well with available experimental data for volumetric flow and particle deposition.

Paper Nr: 99
Title:

Fast Assessment of Wildfire Spatial Hazard with GPGPU

Authors:

Donato D'Ambrosio, Salvatore Di Gregorio, Giuseppe Filippone, Rocco Rongo, William Spataro and Giuseppe A. Trunfio

Abstract: In the field of wildfire risk management the so-called burn probability maps (BPMs) are increasingly used with the aim of estimating the probability of each point of a landscape to be burned under certain environmental conditions. Such BPMs are computed through the explicit simulation of thousands of fires using fast and accurate simulation models. However, even adopting the most optimized simulation algorithms, the building of simulation-based BPMs for large areas results in a highly intensive computational process that makes mandatory the use of high performance computing. In this paper, General-Purpose Computation with Graphics Processing Units (GPGPU) is applied, in conjunction with a specifically devised wildfire simulation model, to the process of BPM building. Using two different GPGPU devices, the paper illustrates two different implementation strategies and discusses some numerical results obtained on a real landscape.

Paper Nr: 112
Title:

Agent based Modelling and Simulation using State Machines

Authors:

Ilias Sakellariou

Abstract: Although agent based modelling has drawn significant attention in the recent years, with a significant number of simulation platforms proposed, the latter target usually relatively simple reactive agents. Thus, little has been done toward enhancing the modelling capabilities of platforms with richer agent oriented programming constructs that could potentially lead to the implementation of more sophisticated models. This paper presents an extension to the TSTATES library that aims to support the implementation of state based intelligent agents and a more complex example drawn from the pedestrian simulation domain that demonstrates the potential of the library in programming complex agent systems.

Paper Nr: 113
Title:

Simulating Vaccination Control and Herd Immunity Threshold in EcoDemics

Authors:

Yasaman Majdabadi Farahani and Robin Gras

Abstract: Modeling infectious diseases and exploring immunization interventions has been a major concern for the last century. Deadly pandemics transmitted from animals to humans such as SARS, rabies, H1N1 and the lack of extensive parameters in most of the epidemic simulations, imposes a great importance on simulating realistic ecosystems to study different aspects of epidemics and mitigation strategies. To this end, EcoDemics was built upon EcoSim to model epidemics in an evolutionary ecosystem simulation. Due to the high mitigation capacity and significance of the immunization intervention, we explore vaccination techniques with various time delays and population proportions. Based on the herd immunity theory, the whole population can be protected against a contagious disease by vaccination of a fraction of individuals. We investigate this principle in EcoDemics and compare our results with real epidemics data.

Short Papers
Paper Nr: 8
Title:

CFD in the Capillary Rheometry of Polyethylene Melts

Authors:

Evan Mitsoulis and Savvas G. Hatzikiriakos

Abstract: The capillary flow of a commercial LDPE melt was studied both experimentally and numerically. The excess pressure drop due to entry (Bagley correction), the compressibility, the effect of pressure and temperature on viscosity on the capillary data analysis have been examined. It was found that only the viscoelastic simulations (using the K-BKZ constitutive relation) were capable of reproducing the experimental data well, while any viscous modeling always underestimates the pressures, especially at the higher apparent shear rates and L/D ratios.

Paper Nr: 21
Title:

Eulerian-Lagrangian Modeling of Forestry Residues Gasification in a Fluidized Bed

Authors:

Jun Xie, Wenqi Zhong, Baosheng Jin, Ming Song, Yingjuan Shao and Hao Liu

Abstract: A comprehensive three-dimensional model is developed to simulate forestry residues gasification in a fluidized bed gasifier using Eulerian-Lagrangian method. Both complex gas-solid flow and chemical reactions are considered. The model is based on the multiphase particle-in-cell (MP-PIC) method, which uses an Eulerian method for fluid phase and a discrete particle method for particle phase. Homogenous and heterogeneous chemistry are described by reduced-chemistry and the reaction rates are solved on the Eulerian grid. Simulations were carried out in a laboratory scale pine gasifier at different operating conditions. The predicted product gas contents and carbon conversion efficiency compare well with the experimental data. The formation of flow patterns, profiles of temperature and distributions of gas compositions were also obtained.

Paper Nr: 34
Title:

Two Modes of Scheduling in a Simple Economic Agent-Based Model

Authors:

Sarah Wolf, Steffen Fürst, Sophie Knell, Wiebke Lass, Daniel Lincke, Antoine Mandel, Jonas Teitge and Carlo Jaeger

Abstract: Agent-based models (ABMs), and with them simulation, are gaining importance in economics. As they allow to study coordination problems in a dynamic setting, they can be helpful tools for identifying win-win strategies for climate policy. This paper argues that strongly simplified models can support a better understanding of economic ABMs. We present work in progress on an example case: while in economic systems in the real world many actions and interactions by various agents take place in parallel, often ABMs use sequential computation. With a simple economic agent-based model of firms that trade and produce goods, we explore and discuss two alternative modes of scheduling: the timetable model, where all agents complete one step after the other, and the heliotropic model, where one agent after the other completes steps. We find that the timetable model is better suited for working with data from national statistics, while the heliotropic model dispenses with random shuffling that is often introduced to guarantee symmetric expectations for agents. The latter can be used in a completely deterministic fashion, providing a baseline case for studying the system’s dynamics.

Paper Nr: 38
Title:

A Fast, Efficient Multi-Direct Forcing of Immersed Boundary Method for Flow in Complex Geometry

Authors:

Anyang Wei, Hui Zhao, Jin Jun and JianRen Fan

Abstract: The Immersed Boundary method (IBM) has received wide attention from last decade, due to its promising application to solve the fluid-solid interaction problems in large quantities of practical engineering areas. This paper implemented IBM with Multi-Direct-Forcing (MDF), presenting the evaluation of momentum forces on the body surface - interaction forces between fluid-solid. Grounded on the Multi-Direct-Forcing method, we constructed a new system that could be efficiently and fast solved. Meanwhile, this proposed algorithm is easy to code and implement parallelization. Besides, it can be extended to three-dimensional simulation without much more extra efforts. Accuracy of the proposed MDF immersed boundary method has been investigated, as well as some applications such as flow past the cylinder at a set of low Reynolds numbers.

Paper Nr: 55
Title:

A Combined DTA Approach for Road Network Robustness Analysis

Authors:

Minwei Li, Henk J. van Zuylen and Huimin Wen

Abstract: In this paper a DTA model with two components is described: a user equilibrium (UE) model and an en-route model. The UE model is called MARPLE (Model for Assignment and Regional Policy Evaluation) that uses an iterative process to achieve equilibrium (deterministic or stochastic) (Taale et al., 2004). In each iteration a network loading model is used to determine travel times. MARPLE en-route is developed based on the MARPLE model, which runs one-shot simulation starting with the equilibrium assignment results. It updates the path sets and path costs after each evaluation interval during the simulation. Travellers will update their path choice according to the instantaneous path costs at the end of each interval using some heuristic rules. A systematic framework for the robustness study of road networks is built up by combining both DTA approaches, in which the results of UE approach are used as references and en-route approach is used to simulate the network response for non-recurrent and short-term disturbances. The results for a hypothetical network show that for evaluating the network performance after such disturbances, the en-route assignment approach based on UE assignment results shows its capability and advantages in appropriately representing dynamic drivers’ route choice behaviour when facing unfamiliar or unexpected situations on the route.

Paper Nr: 72
Title:

SysML Parametric Models for Complex System Performance Analysis - A Case Study

Authors:

Nga Nguyen and Hubert Kadima

Abstract: Parametric analysis is an essential tool in optimizing the performance of any system; it is, in particular, used to fine-tune key parameters in a system design process. In this paper, using a vehicle cruise control system as a non-trivial case study, we introduce a new approach for the performance parametric analysis of complex systems using SysML models and a parametric constraint solver. System requirements are taken into account to verify automatically whether the design solutions satisfy these requirements. This suggests that in order to reduce time and resources, it is possible to perform initial performance analysis in a modeling tool, just after the system functional and architectural analyses. Of course, once an approximate operating point has been determined using this approach, experiments in specialized simulation tools can be used to confirm and further refine the parameters of a system.

Paper Nr: 82
Title:

Enhancing the RAMSAS Method for System Reliability Analysis - An Exploitation in the Automotive Domain

Authors:

Alfredo Garro and Andrea Tundis

Abstract: The paper proposes an enhancement and exploitation of the RAMSAS method, a model-based method for system reliability analysis which combines in a unified framework the benefits of popular OMG modeling languages (UML, SysML) with the wide adopted Mathworks simulation and analysis environments (Matlab, Simulink). The flexibility and scalability of the proposal, as well as its effectiveness in evaluating through simulation the system reliability performances, is exemplified through a case study in the automotive domain.

Paper Nr: 87
Title:

Modeling Cell Populations in Development using Individual Stochastic Regulatory Networks

Authors:

Paweł Bednarz and Bartek Wilczyński

Abstract: We present a new approach to high level stochastic simulations of cell populations. The proposed method employs the Stochastic Logical Network (SLN) method for simulating independent regulatory processes occurring in individual cells allowing for efficient simulations of systems consisting of thousands of cells. The stochastic logical network model is extended to account for not only regulatory control of gene expression but other related processes such as: inter-cellular signaling, cell division and programmed cell death. In the paper, we present the method and several case studies, where the proposed approach is used to provide models of biological phenomena. These examples include community effect in gene expression, the role of negative feedback in growing epithelial cell lineage and the role of asymmetric cell division in cell fate choices. We present also an efficient implementation of the method using GPU computing and show that its performance is significantly better than that using CPU.

Posters
Paper Nr: 35
Title:

Parametric Study of Complex Liquid Flow in a Centrifugal Pump Consisting of an Impeller, a Volute and a Diffuser

Authors:

Guyh Dituba Ngoma, Walid Ghie and Nicolas La Roche-Carrier

Abstract: In this work, the numerical investigation of the complex liquid flow in a centrifugal pump modelconsisting of an impeller, a diffuser and a volute was done to analyze the effects that the blade height, the diffuser blade number, and the volute size had on the pump performance. The continuity and Navier-Stokes equations with the k- turbulence model and the standard wall functions based on the logarithmic law were used by mean of ANSYS-CFX code. The results achieved reveal that the selected key design parameters have an impact on the pump head, the brake horsepower and the overall efficiency.

Area 4 - Application Domains

Full Papers
Paper Nr: 15
Title:

Simulation of Backflow in Automotive Body Assemblies

Authors:

Jaedeuk Yun, Sunghoon Lee, Jianhui Fu, Jungwoon Lee, Yoongho Jung and Sungbae Park

Abstract: The many parts required for aircraft and automotive development are developed by functional or sectional design groups for efficiency. Interferences and gaps can be found when the parts and subassemblies from those design groups are to be assembled. When rainwater enters the spaces between parts and there is not sufficient drainage, the rainwater within the structure can backflow to gaps or unexpected outlets, which may cause severe problems of part corrosion and electric shock. We have developed a method and a program to simulate backflow of rainwater within spaces between automotive parts; the method can find unexpected outlets and gaps. The developed program can simulate not only simple liquid flows, but also division and joining of flows with multiple channels. The developed method can also be applied to aircraft and ship design.

Paper Nr: 32
Title:

Hybrid Simulation Approach for Prospective Assessment of Mobile Stroke Units

Authors:

Anatoli Djanatliev, Peter Kolominsky-Rabas, Bernd M. Hofmann, Axel Aisenbrey and Reinhard German

Abstract: Technology innovations in health care offer high potentials for all stakeholders (e.g., patients, healthcare providers and health industry), but the development phase of such innovations is often very expensive and the effects are hardly predictable without a systematic strategy. The new interdisciplinary approach Prospective Health Technology Assessment (ProHTA) uses simulation techniques to indicate the effects of new health technologies, early before the cost-intensive development process begins. Furthermore, ProHTA helps to detect gaps and bottlenecks in the health system to catch potentials for new innovations. The scope of ProHTA includes both a strategic aggregated level of analyses as well as an individual detailed level. This paper describes the use of hybrid simulation approaches, consisting of System Dynamics and Agent-Based Simulation, to analyze the effects of an innovative stroke technology. We discuss an example of the prospective assessment of Mobile Stroke Units within a Metropolitan Scenario. The project ProHTA is a part of the Centre of Excellence for Medical Technology - Medical Valley EMN - and is supported by the German Federal Ministry of Education and Research (BMBF), project grant No. 01EX1013B.

Paper Nr: 53
Title:

Machine Modelling for Transient Stability Analysis in Distribution Grids - A Comparison of Synchronous and Induction Machine Models in Medium and Low Voltage Grids

Authors:

Johannes Weidner and Lutz Hofmann

Abstract: The complete models for synchronous and induction machines are compared with selected approximated models. This is to validate the approximations for the utilisation in transient stability analysis in distribution grids. The results show that they can be used to simulate stable oscillations, but they lose their accuracy approaching the area of transient instability. The main reason is the active power exchange during faults, which is not jumping to zero as it does in high voltage scenarios.

Paper Nr: 61
Title:

Plant Level Framework for Material Flow in a Nuclear Reprocessing Facility

Authors:

Hyo Jik Lee, Won Il Ko and Han Soo Lee

Abstract: A plant level framework has been developed for a nuclear recycling facility. A plant level model generally consists of multi-tiered models. The bottommost tier is a unit process model regarding electro-chemical phenomenon. The middle tier is an operation model regarding mechanical handling of the process equipment. The topmost tier is a systemic integration in the level of the plant. Even though a unit process model is fundamental to build higher tier models it takes time to make a model with high fidelity. Therefore, a different strategy for a plant level model building is suggested in this study. One of the important issues that nuclear recycling process must consider is dynamic material flow, which could be done with the help of a unit process model. However, from plant level aspect, it can be simply obtained from mass balance sheet rather than understanding of electro-chemical behavior during process time. A plant level framework was suggested to be able to include dynamic material flow even without a unit process model. Thus, a more reliable unit process model can be added later selectively. The characteristic of the current framework was addressed and evaluated for further improvement. The current version of the plant-level-framework could provide many unforeseeable results which are difficult to obtain by intuition. Nevertheless, the next version will include more function to provide various analyses linked with other nuclear related codes.

Paper Nr: 75
Title:

Simulation of Photovoltaics for Defence Applications - Power Generation Assessment and Investigation of the Available Integration Areas of Photovoltaic Devices on a Virtual Infantryman

Authors:

Ioannis Paraskevopoulos and Emmanuel Tsekleves

Abstract: The use of photovoltaic (PV) technology for the harvesting of renewable energy is a reality and is widely employed today. However this is mainly focused towards house and industry energy harvesting. Recent development in thin and flexible materials mean that photovoltaic technology can be integrated into wearable computing and expanded to other commercial as well as defence applications. This paper presents work under the Solar Soldier project that aims to assess the incorporation of flexible PV technology on the modern infantry soldier through the modelling and simulation of virtual military scenarios. The scenarios consist of various military operational terrains, various lighting conditions as well as motions of the virtual infantry soldier. The scenarios are simulated in a systematic way and for numerous global positions of military interest. The results of these simulations are then organised and presented in a manner leading to the assessment of the power generation potential per scenario and investigation of the optimum integration areas of flexible PV devices on the infantryman.

Paper Nr: 96
Title:

Dynamic Simulation of Opioid Misuse Outcomes

Authors:

Alexandra Nielsen and Wayne Wakeland

Abstract: The objective of the study was to develop a system dynamics model of the medical use of pharmaceutical opioids, and the associated diversion and nonmedical use of these drugs. The model was used to test the impact of simulated interventions in this complex system. The study relied on secondary data obtained from the literature and from other public sources for the period 1995 to 2008. In addition, an expert panel provided recommendations regarding model parameters and model structure. The behaviour of the resulting systems-level model compared favourably with reference behaviour data (R2=.95). After the base model was tested, logic to simulate interventions was added and the impact on overdose deaths was evaluated over a seven-year period, 2008-2015. Principal findings were that the introduction of a tamper resistant formulation unexpectedly increased total overdose deaths. This was due to increased prescribing which counteracted the drop in the death rate. We conclude that it is important to choose metrics carefully, and that the system dynamics modelling approach can help to evaluate interventions intended to ameliorate the adverse outcomes in the complex system associated with treating pain via opioids.

Paper Nr: 111
Title:

Optimizing Energy using Probabilistic Routing in Underwater Sensor Network

Authors:

Sanjay K. Dhurandher, Mohammad S. Obaidat, Abhishek Gupta, Prateek Gupta and Siddharth Goel

Abstract: As the Importance of Applications, Such as Ocean Sampling, Environmental Monitoring, Disaster Prevention, and Distributed Tactical Surveillance, Has Recently Grown, the Need for Underwater Communication Has Become More Pronounced. unlike Terrestrial Sensor Networks, Underwater Sensor Networks (Uwsns) Have Different Characteristics Such as a Long Propagation Delay, a Narrow Bandwidth and High Packet Loss.Considering the Various Challenges Posed by the Underwater Environment, a Routing Algorithm Has Been Proposed in This Paper. the Algorithm Consists of Special Features, including Three Different Types of Nodes in the Architecture Proposed, a Mathematical Formula in Order to Select the next Node to Be Used for Transmission. The Major Aim of the Algorithm Is to Select the next Node to Be Used for Successful Data Delivery, and Ensure Minimum Energy Consumption. the next Node Is Chosen With Utmost Care in Order to Increase the Probability of Successful Data Delivery. the Packet Is Transferred from the Source to the Sub-Destination by Exploiting Minimum Energy of the Nodes. the Simulation Studies for the Protocol Were Conducted using AQUA-GLOMO Network Simulator. the Protocol Was Benchmarked With DSR Routing Protocol. The Matrices That Were Considered for the Simulation Study Were Throughput, PDR, Energy Consumption and Delay and It Was Observed That Our Proposed Model Performed Better in the Underwater Environment.

Short Papers
Paper Nr: 10
Title:

The Improved SSR Electromagnetic Simulation Model and Its Comparison with Field Measurements

Authors:

Xiaorong Xie, Yipeng Dong, Kai Bai, Xun Gao and Ping Liu

Abstract: Electromagnetic simulation (EMS) plays an important role in the evaluation of subsynchronous resonance (SSR). To meet the requirement of practical engineering, this paper discusses how to improve the modeling method of SSR-EMS in three important aspects, i.e., the shaft system of turbine generator, the series compensation and the supplementary excitation damping controller (SEDC). Thus a systematically improved EMS model was put forward, which includes a lumped mass-spring model with adjustable and non-linear mechanical damping, a series compensation model incorporating MOV with the gap protection logic and an engineering model of SEDC to reflect the dynamics of the power-electronic exciter. The developed model overcomes the shortage of the traditional one and is applicable to the accurate analysis on SSR stability, transient torque and fatigue expenditure when the system experiences large disturbances. The proposed method is then used for the simulation of a real SSR event caused by a short-circuit fault in the Shangdu series-compensated power system. The simulation results are compared with the field measurements and a good consistence is found. Consequently, the improved EMS model is proved to be applicable, accurate and effective for SSR analysis in practical engineering.

Paper Nr: 47
Title:

Job-shop Problems with Objectives Appropriate for Train Scheduling in a Single-track Railway

Authors:

Omid Gholami, Yuri N. Sotskov and Frank Werner

Abstract: A train scheduling problem in a single-track railway is studied using a mixed graph model for a job-shop with appropriate criteria. There are several performance evaluations for a train schedule. Optimizing a train schedule subtends minimizing total tardiness of the trains, minimizing the sum of train transit times, minimizing the makespan for a train schedule, etc. Since the corresponding job-shop problems with the above three criteria are NP-hard, several heuristic algorithms have been developed using different priorities based on the release times of the jobs, the job due-dates and the job completion times. Experiments on a computer were used for evaluating the quality and efficiency of the heuristic algorithms developed for appropriate job-shop problems. The release times, due-dates and completion times of the jobs have been used as input parameters (priorities) in the computer simulation to see the effect of them on the quality of the schedules with different objective functions. The efficiency of the developed heuristics was demonstrated via a simulation on a set of randomly generated instances of small and medium sizes. The computational results showed that one heuristic algorithm outperformed the other algorithms tested for two of the three objective functions under consideration.

Paper Nr: 48
Title:

Optimizing Operation Costs of the Heating System of a Household using Model Predictive Control Considering a Local PV Installation

Authors:

Cosmin Koch-Ciobotaru, Fridrik Rafn Isleifsson and Oliver Gehrke

Abstract: This paper presents a model predictive controller developed in order to minimize the cost of grid energy consumption and maximize the amount of energy consumed from a local photovoltaic (PV) installation. The usage of as much locally produced renewable energy sources (RES) as possible, diminishes the effects of their large penetration in the distribution grid and reduces overloading the grid capacity, which is an increasing problem for the power system. The controller uses 24 hour prediction data for the ambient temperature, the solar irradiance, and for the PV output power. Simulation results of a thermostatic controller, a MPC with grid price optimization, and the proposed MPC are presented and discussed.

Paper Nr: 91
Title:

Flatness based Control of a 2 DOF Single Link Flexible Joint Manipulator

Authors:

E. D. Markus, J. T. Agee, A. A. Jimoh, N. Tlale and B. Zafer

Abstract: The demand for high speed robotic manipulators with little or no vibrations has been a challenging research problem. In this paper, a position control for a 2 DOF single link flexible manipulator with joint elasticity is studied. It is shown that using the flatness control approach, faster response and less oscillations and overshoots can be achieved. The flat output of the linearized system is determined as the tip of the manipulator end effector. This output and a finite order of its derivatives is defined in terms of the input and states variables of the manipulator. Using the parameters of the output in flat space, a trajectory is planned and executed to test the effectiveness of the designed control.

Posters
Paper Nr: 16
Title:

Strategic and Standardized Simulation of a Distribution Network - A Case for a Drugstore Company in Mexico

Authors:

Homero H. Contrera, José Pablo Nuño, Eric Porras and Eduardo Zelaya

Abstract: Analysis of distribution network is a crucial issue in supply chain management. There is a vast array of analysis tools for logistics, but analytic tools cannot deal with the inherited variability. Thus, simulation might be a better alternative, and the use of standardized models represents a promising areas. In this paper, a simulation model facing a strategic approach will be proposed as a way to analyze a distribution network based on model consisting of two-echelons; this model can work both forwards and backwards in a recursive manner, and relies on operative key performance indicators that affect the strategy in the long term. Using a standardized model increases flexibility, focus the problem and provides a better computer performance. The model is validated through a business case for a Mexican company dealing with bottom of pyramid clients in the drugstore sector.

Paper Nr: 41
Title:

Practical Considerations for Enabling a srTCM Behavior in Opnet Modeler

Authors:

Pana Flavius and Put Ferdi

Abstract: Different Quality of Service (QoS) mechanisms have been proposed over time. Differentiated Services (DiffServ) represents one of the main QoS mechanisms developed, and is based on a strategy of traffic differentiation. Introduced in order to be used within DiffServ, the single rate Three Color Marker (srTCM) represents a policer which meters the IP packet stream and marks the traffic with different drop probabilities. This paper presents the technical aspects of implementing the srTCM in one of the most important network simulation tools on the market, OPNET Modeller. Practical considerations and a test case of the proposed implementation are presented.