SIMUTools2010

Pero Latkoski, Valentin Rakovic, Ognen Ognenoski, Vladimir Atanasovski and Liljana Gavrilovska.
SDL+QualNet: A Novel Simulation Environment for Wireless Heterogeneous Networks

Abstract: The development of new network communication protocols has to include a process of concept evaluation in order to prove its soundness. Simulation-based techniques provide assessment of communication quality in complex and realistic working conditions. This paper introduces a novel and unique combined simulation technique, by merging the QualNet simulator and the SDL protocol developer. Many complex modifications of the QualNet nodes, including totally new communication procedures, can be efficiently implemented, which is very difficult by a straightforward re-coding of QualNet components. The proposed methodology was utilized in the development process of a wireless heterogeneous IEEE 802.21-based network. The paper provides a detailed insight of the model’s three basic parts: QualNet simulation environment, SDL developed radio resource manager and the novel SDL2QualNet interface. We present useful information for 802.21 simulation implementation, data acquisition from QualNet and calculation of dynamic network parameters needed for the resource manager, information transmission and buffer management, methods for improvement of simulation efficiency, and many other modeling and simulation hints which enable a comprehensive wireless heterogeneous network simulation  platform.

Shun Nakamura, Kazuo Furuta, Taro Kanno, Shigeki Yoshihara and Takamichi Mase.
Multi-Agent Simulation of Ground Aircraft Operations at a Large Airport

Abstract: How to realize efficient ground aircraft operations at a large airport is a key issue to respond increasing air traffic demands. This study aims at establishing a systematic and concrete method for assessing not only ground facility designs but also operation schemes in terms of aircraft operations on airfields. A multi-agent simulation system was developed for ground aircraft operations based on the simulation model constructed through field visit and observation considering implicit action rules of field experts. An interactive design process of visualizing simulation results, showing them to field experts, getting their opinions, and considering the obtained feedbacks is very effective for brush-up of the simulation model or design plans.
Comparison of simulation results with the field data demonstrated that the simulation system can well predict the actual operation performance and that it is useful to comparatively assess design plans for ground aircraft operations. The method proposed was then applied to a case study to assess the operation plans expected after the scheduled extension of a runway and a terminal building at Tokyo International Airport (Haneda). As a result of simulation, several problems in the present plans could be pointed out, and the findings will be useful to revise them.

Georg Möstl, Richard Hagelauer, Andreas Springer and Gerhard Mülller.
Including Real-Life Application Code into Power Aware Network Simulation

Abstract: We present a methodology and a toolset for power aware HW/SW co-simulation including real-life application code at network level. The toolset consists of the known OMNeT++ network simulation environment and the PAWiS framework, which was extended to include time-annotated and natively executing C code, and allows detailed analysis of the power consumption of single modules in the network. In conjunction with the support of interrupt handling, this especially addresses the needs of applications running on nodes of wireless sensor networks (WSNs). The presented partitioning of the application into platform-dependent and platform-independent SW layers provides easy porting of the simulated code to real sensor nodes. To demonstrate the functionality of this approach, the methodology was applied to a simple real-world networking test scenario and the achieved simulation results are compared to real-world measurements.

Rainer Bye, , Jan Clausen, Karsten Bsufka and Sahin Albayrak.
Optimization and Early-Warning in DSL Access Networks based on Simulation

Abstract: Network providers run large DSL-based access networks to o ffer customers Broadband Internet. But, these networks are to be observed and controlled by performance management systems to cope with incidnets such as link failures or congestions. In this research, we present a performance management optimization approach using in particular simulation. In this regard, we present traffic models based on real network performance data reflecting: (I) individual subscribers and (II) an aggregated model for multiple subscribers. Next, we introduce the overall simulation approach based on an extension mechanism incorporated in the Network Security Simulator NeSSi². Third, we conduct a use case for simulation-based verication of applied optimization strategies and a use case for continuous forecast to predict upcoming link congestions.

Mario Montagud and Fernando Boronat.
A new Network Simulator 2 (NS-2) module based on RTP/RTCP protocols to achieve Multimedia Group and Inter-Stream Synchronization

Abstract: Network simulation represents a broadly methodology for communication network performance analysis. As a system modeling approach, simulation allows one to model arbitrary scenarios that many times are very difficult to implement in practical platforms, or when it is intended to evaluate some alternative solutions without necessity of implementing all of them.  In this paper, we present a modification of the NS-2 code for the RTP/RTCP standard protocols by adding all the attributes that are specified in RFC 3550. Also, we have extended this code to include a multimedia group and inter-stream synchronization approach using these protocols. RTP protocol is used for data stream transmission and RTCP is used for participants’ feedback information transmission. This approach was already implemented and evaluated in a real WAN scenario with satisfactory results, but we needed to validate its performance in other more complex heterogeneous scenarios using simulation techniques. The simulation results have proved this approach as a suitable solution for multimedia applications which require group and inter-stream synchronization.

Petr Matousek, Ondrej Rysavy, Gayan de Silva and Martin Danko.
Combination of Simulation and Formal Methods to Survivability Network Survivability

Abstract: Modern computer networks are complex and their topology can dynamically change when links go down. It is difficult to predict behaviour of a large network with dynamic routing protocols. To automatically prove survivability and reliability of an end-to-end connection, formal analysis combined with simulation can be exploited. In this paper, an approach based on detection of critical elements using formal analysis and subsequent simulation of time related properties is introduced. Our network model is based on graph theory and is automatically extracted from configurations of network devices. Then, critical network elements are detected using graph search algorithms. In addition to graph analysis, several simulation scenarios are executed over the model in order to detect time dependencies. Modeling and simulation is done in OMNeT++ simulator, formal analysis is computed using scripting. The first results of this combined analysis show feasability of this
approach and help to reveal both qualitative parameters (status of links and nodes), and  quantitative parameters (timers, routing protocols) that influence reliability and survivability of the network. The approach is demonstrated on a simplified topology of Czech Academic Network (CESNET).

Mohamed Amine Ismail, Giuseppe Piro, Luigi Alfredo Grieco and Thierry Turletti.
An Improved IEEE 802.16 WiMAX Module for the ns-3 Simulator

Abstract: IEEE 802.16 WiMAX is a promising new wireless technology for providing broadband ubiquitous network access. As more and more researchers and industrials are interested in simulating such networks, a number of WiMAX simulators have been emerged in the networking community. One of the most recent WiMAX simulator is the one developed for ns-3. This module provides a standard compliant and well designed implementation of the standard and benefits from the major enhancements provided by ns-3 (compared to other network simulators) which has all the capabilities of becoming the leading network simulator in near future. However, this WiMAX module still lacks some important features which motivated this work. In this paper, we first provide a snapshot of existing WiMAX simulators available in the public domain, while highlighting their limitations. Then, we describe the new features and enhancements we have integrated within the ns-3 WiMAX module, and in particular: a realistic and scalable physical model, an IP packet classifier for the convergence sub-layer, efficient uplink and downlink schedulers, support for multicast traffic and pcap packet tracing functionality. The new design of the physical layer has improved the simulation time by several magnitude orders while still providing a realistic implementation of the standard. Furthermore, the IP classifier has enabled the simulation of an unlimited number of service flows per subscriber station, while the proposed schedulers improve the management of the QoS requirements for the different service flows.

Francesco Cece, Valerio Formicola, Francesco Oliviero and Simon Pietro Romano.
An Extended ns-2 for Validation of Load Balancing Algorithms in Content Delivery Networks

Abstract: This paper deals with the design, the development and the usage guidelines of a novel Content Delivery Network library for the ns2 simulator. Such library allows evaluating new application-level load balancing approaches, in particular referred to distributed content web servers. It includes some typical load balancing algorithms proposed in the literature and it can be extended to support new solutions. The proposed tool extends the ns2 simulator with new HTTP data types and new application components which are in charge of data treatment. Moreover a new agent has been added to allow the simulation of data transferring. The library has been designed to work  n a non-hierarchical and peer to peer cooperation environment. Several examples of testing scenarios are proposed in the paper.

Alberto Alvarez, Rafael Orea, Sergio Cabrero, Xabiel G. Pañeda, Roberto García and David Melendi.
Limitations of network emulation with single-machine and distributed ns-3

Abstract: Research on large-scale internet services requires an extensive evaluation prior to deployment. A good analysis must include tests over large networks, using real devices and a considerable number of users. However, how to test in these scenarios with many users is an open question. Network emulation can be a good alternative before real deployments, which are complex and expensive. In this paper, we examine the new ns-3 network simulator/emulator in order to determine its capacity in the evaluation of large scale services. For that purpose, a real client/server video service is deployed over an emulated network. The service is progressively scaled up by increasing the number of clients on a single machine. In addition, we have extended ns-3 to support a distributed architecture for network nodes, thus, we repeat the experiments with a distributed set-up. Advantages, disadvantages, possibilities and limitations of both approaches are thoroughly discussed.

Nicola Baldo, Manuel Requena, Jose Nunez, Marc Portoles, Jaume Nin, Paolo Dini and Josep Mangues.
Validation of the ns-3 IEEE 802.11 model using the EXTREME testbed

Abstract: We validate the IEEE 802.11 MAC layer model in ns-3 by means of measurements on the EXTREME testbed. We consider different scenarios of interest: single pair communications, multi-user VoIP, multi-user saturated, and hidden node. For each scenario we describe in detail our testbed and simulation setup, and compare the results provided by the ns-3 simulator with the performance measured on the testbed.

Euiyul Ko, Hanjin Park and Ikjun Yeom.
A New Event-Driven Network Simulator for Delay-Tolerant Networks (DTNs)

Abstract: As wireless networking technologies have evolved, wireless networks are deployed in wider areas. In some of them, end-to-end paths may not be guaranteed due to high mobility or low density of network nodes. Delay/Disruption Tolerant Networks (DTNs) or Intermittently Connected Networks (ICNs) are proposed to handle packet delivery in those networks. In DTNs, network simulation may play a critical role for developing new technologies since it is very expensive and time-consuming to perform real experiments. In this paper, we present a new simulation tool for DTNs. This tool is developed with an event-driven manner to accommodate discrete events in packet delivery processes in DTNs, and also it is highly flexible and easily extensible for developing new protocols. We validate the tool with well-known mathematical models of DTNs.

Wan Du, David Navarro, Fabien Mieyeville and Frédéric Gaffiot.
Towards a Taxonomy of Simulation Tools for Wireless Sensor Network

Abstract: Many limitations (e.g. complexity, cost, scalability and capability) make the analytical methods and physical testbeds improper to evaluate the performances of wireless sensor networks (WSNs). Simulations can provide a good approximation at lower cost and in less time. Hence, a number of simulation tools for WSN have been developed in the past few years. However, different tools may emphasize on different features. For example, besides the general network simulators, some SystemC-based simulators have been developed recently in order to realize the hardware/software (HW/SW) co-design of the node system (hardware and software of a single sensor node) at the system-level that also takes into account its network performances. So it is necessary to study the existing WSN simulators and to distinguish their different features. In this paper, we propose a classification scheme that categorizes the existing simulation tools into four classes according to their modeling methodologies. In order to prove that the proposed taxonomy is reasonable and comprehensive, we use it to make a survey of the existing simulation tools. This study is intended to be broad enough to cover all the important existing simulation tools, including some newer ones, e.g. one in published in 2009. The goal of this paper is to analyze the WSN simulation tools and help the WSN designers find an appropriate simulator to their special requirements.

Gustavo Vejarano and Janise McNair.
WiMAX-RBDS-Sim: An OPNET Simulation Framework for IEEE 802.16 Mesh Networks

Abstract: In this paper, a simulation model for IEEE 802.16 (WiMAX) wireless mesh networks with distributed scheduling is developed. It provides a framework for the evaluation and comparison of reservation-based distributed scheduling (RBDS) policies at the medium access control (MAC) layer. The simulation model, called WiMAX-RBDS-Sim, is developed under the OPNET event-driven simulation environment. It provides interfaces for the integration of RBDS policies and link-establishment algorithms. As an example of the use of WiMAX-RBDS-Sim, a new RBDS policy is proposed and evaluated with it. This policy is called Sliced-GM-RBDS and is based on the GM-RBDS policy proposed in (:cell PQA(PSS(20):). The WiMAX-RBDS-Sim simulation results show that Sliced-GM-RBDS outperforms GM-RBDS in terms of network stability. Finally, a link-establishment algorithm is also evaluated with WiMAX-RBDS-Sim. This evaluation is performed in terms of the time required for the completion of link establishments across the network.

Fatma Hrizi and Fethi Filali.
An Integrated and Realistic Simulation Platform for Vehicular Networks

Abstract: In the last few years, a rapid emergence of vehicular networks has been perceived. The premise that vehicular communications can enhance road safety and efficiency has increased the interests of both governments and private entities to support several national and international projects around the globe. Since this new kind of networks requires the design of new communication protocols, many efforts have been conducted in previous researches. The performance evaluation of these proposals is a crucial step for their validation. Therefore, the need for an open-source, realistic and integrated simulation environment is a fundamental and extremely pervasive motivation behind this work. In this paper, we describe the main architecture of a realistic and open-source platform. Additionally, we provide the details about its implementation. Using ns-3 as a network simulator and SUMO as a road traffic simulator, the main idea is to integrate these two types of simulation environments in order to make the simulation more realistic by the real time exchange of simulation data. The proposed simulation platform is mainly designed to enable researchers to better evaluate communication protocols for vehicular networks in realistic constraints.

Isabel Dietrich, Falko Dressler, Winfried Dulz and Reinhard German.
Validating UML Simulation Models with Model-Level Unit Tests

Abstract: We describe model-level unit tests for model-driven simulation based on UML models. We refer to the well-known unit testing method and apply this concept on a higher abstraction level, that is on UML simulation models. The concept of model-based simulation has become more and more popular throughout the last years. This trend is fostered by the availability of tools that automatically transform UML models into executable simulation code. Typically, both functionality and behavior are modeled in UML, whereas debugging and validation are mainly an issue of investigating the executable code. We contribute to the field of model-driven simulation by defining a novel testing method. Our method allows the modeler to stay with abstract models by providing means to specify test cases in UML. In spite of the high abstraction level, the full functionality of unit testing is provided and the modeler can rely on automated test case generation and execution. In this paper, we show the principles of this method and discuss its use in the scope of our simulation framework Syntony as well as its general applicability. Our implementation allows to compile and to execute the test code in combination with the simulation code. After execution of the tests, the achieved test coverage is computed as a measure for the test quality.

Daniel Cordeiro, Gregory Mounie, Swann Perarnau, Denis Trystram, Jean-Marc Vincent and Frederic Wagner.
Random graph generation for scheduling simulations

Abstract: In parallel and distributed systems, validation of scheduling heuristics is usually done by simulation on randomly generated synthetic workloads, typically represented by task graphs. Since there is no single generation method that models all possible workloads for scheduling problems, researchers often re-implement the classical generation algorithms or even implement ad hoc ones. A bad choice of generation method can mislead the validation of the algorithm due to biases it can induce. Moreover, different implementations of the same randomized generation method may produce slightly different graphs. These problems can harm the experimental comparison of scheduling algorithms. In order to provide a comparison basis we propose GGen -- a unified and standard implementation of classical task graph generation methods used in the scheduling domain. We also provide an in-depth analysis of each generation method, emphasizing important graph properties that may influence scheduling algorithms.

Matthew Collinson, Brian Monahan and David Pym.
Semantics for Structured Systems Modelling and Simulation

Abstract: Simulation modelling is an important tool for exploring and reasoning about the dynamics and properties of complex systems, and many supporting languages are available. Commonly occurring features of these languages are constructs that capture concepts such as process, resource, and location. We describe a mathematical framework that supports a modelling idiom based on these core concepts, and which also adopts stochastic methods for representing the environments within which systems exist. We explain how this framework can be used to give a formal  semantics to a simulation modelling language, Core Gnosis, that includes basic constructs for process, resource, and location. We include a brief discussion of a system of logic for reasoning about our models that is compositional with respect to the structure of models. We believe that our mathematical analysis of systems in terms of process, resource, location, and stochastic environment, together with a language that captures these concepts quite directly, leads to an efficient and robust modelling framework within which natural mathematical reasoning about systems is captured in the associated tools.

Sebastian Max, Daniel Bültmann, Ralf Jennen and Marc Schinnenburg.
Evaluation of IMT-Advanced Scenarios using the open Wireless Network Simulator

Abstract: With the commence of the IMT-Advanced (IMT-A) submission and evaluation process, the vague term "4th generation wireless networks" moves towards existing standards, technologies and hardware. A signifcant part of the evaluation process is based on the system level simulation of reference scenarios. In this paper, we present how the open Wireless Network Simulator (openWNS), developed in the last 5 years at the department of Communication Networks (ComNets) at RWTH Aachen University, can be used to study protocols of wireless networks. Due to the complexity of IMT-A candidate systems, the features of openWNS are described by means of the lightweight WiFiMAC. This module provides the functions of IEEE 802.11, including amendment n. On this basis, the following details of the simulator are explained: (a) the modular simulation framework for protocol stack development, (b) the WiFiMAC module, (c) simulator calibration to ensure the reliability of the results and (d) the simulation of urban-micro scenarios based on the IMT-A evaluation guidelines.

Jinglong Zhou, Anthony Lo and Ignas Niemegeers.
Evaluation of MPEG-4 Video Streaming Over Multi-hop Cellular Networks

Abstract: Next generation communication networks will comprise third-generation (3G) cellular and multi-hop ad hoc networks. MPEG-4 video streaming can be a killer application for this novel multi-hop cellular network. The paper has evaluated the end-to-end performance of streaming MPEG-4 video over a multi-hop cellular network that comprises the High-speed Downlink Packet Access (HSDPA), Universal Mobile Telecommunication System (UMTS) and the IEEE 802.11 ad hoc networks. The factors, which can affect the end-to-end performance of MPEG-4 video transmission, are analyzed using simulation. For the same configurations, the simulation results reveal that different MPEG-4 video contents can cause different performance for HSDPA. The transmission strategies used in HSDPA and UMTS also results in performance differences. Moreover, the number of hops, error rate in the 802.11 multi-hop network and traffic contentions level have a strong impact on the end-to-end MPEG-4 video streaming performance. Our results can be used for gateway selection, resource reservation and QoS provision in the novel multi-hop cellular network.

Stefan Leye and Adelinde M. Uhrmacher.
A flexible and extensible architecture for experimental model validation

Abstract: With the rising number and diversity of validation methods, the need for a tool supporting an easy exploitation of those methods emerges. We introduce FAMVal, a validation architecture that supports the seamless integration of different validation techniques. We structure a validation experiment into the tasks specification of requirements, configuration of the model, model execution, observation, analysis, and evaluation. This structuring improves the flexibility of the approach, by facilitating the combination of methods for different tasks. In addition to the overall architecture, basic components and their interactions are presented.
The usage of FAMVal is illuminated by several validation experiments with a small chemical model. The architecture has been realized using the plug-in based design of the modeling and simulation framework JAMES II.

Stefan Leye, Mathias John and Adelinde M. Uhrmacher.
A flexible architecture for performance experiments with the pi-Calculus and its extensions

Abstract: The pi-Calculus is a modeling formalism for concurrent processes. Realized as part of the plug-in based modeling and simulation framework JAMES II, we propose an architecture for pi-Calculus-based modeling and simulation, which supports both: flexibility and efficiency. Facilitating the design of new pi-Calculus-based formalisms and simulators is of particular relevance in the field of computational systems biology, for which many different pi-Calculus dialects and simulators have been and still are being developed. Therefore, a flexible representation of pi-Calculus models is used, which is illustrated by a mapping from the biochemical variant of the pi-Calculus to the representation. Simulation engines are exchangeable and even automatically configurable according to the task at hand. Moreover, we present three different simulator implementations, working on the model representation. Efficiency denotes, that our architecture supports the implementation of high-performance simulators. In order to proof efficiency, we perform experiments with these simulators and compare the results to the current cutting edge implementation in the field, the Stochastic Pi Machine.

Jörg Dallmeyer, Tjorben Bogon, Yann Lorion and Ingo J. Timm.
Migration simulation on potential field based landscapes

Abstract: In this paper we present a novel migration simulation of entities over landscapes. The entities can explore the environment or ``walk" from point to point depending on their programmable attributes. For a fast adaptation to new maps we have developed a converter which creates 3D-landscapes from 2D satellite (or map) images. With different color codes the different altitudes are represented and automatically converted into the landscape. The underlying system is based on a potential field which is fully configurable and extendable for additional information about the landscape (weather, GIS). We show how this simulation can be applied to researches by simulating for example human-migrants over a specific landscape and helps to get information about the course of the walking-tour.

Eric Heien, Masao Okita, Yoshiyuki Asai, Taishin Nomura and Kenichi Hagihara.
insilicoSim: an Extendable Engine for Parallel Heterogeneous Biophysical Simulations

Abstract: Recently, several multidisciplinary projects have begun to model and simulate human physiological systems.  However, the simulators for these models are often limited in terms of simulation type and lack of parallel computing support.  In this paper we describe insilicoSim, an extendable simulation engine for performing parallel large scale biophysical simulations.  We present three key components of the simulator for improving extensibility and performance.  First, we demonstrate how a standardized plugin interface allows for easy extension of the simulator to new types of input, output and simulation methods.  We detail a technique for improving simulation performance by simplifying and compiling simulation related mathematical expressions into an internal byte code representation for fast evaluation.  Finally, we describe the simulation object manager which allows for shared object access between simulation interfaces while transparently performing parallel synchronization.  We demonstrate the effectiveness of these methods by simulating several models on both serial and parallel computing platforms.

Judicael Ribault, Olivier Dalle, Denis Conan and Sebastien Leriche.
OSIF: A Framework To Instrument, Validate, and Analyze Simulations

Abstract: In most existing simulators, the outputs of a simulation run consist either in a simulation report generated at the end of the run and summarizing the statistics of interest, or in a (set of) trace file(s) containing raw data samples produced and saved regularly during the run, for later post-processing.  In this paper, we address issues related to the management of these data and their on-line processing, such as: (i)~the instrumentation code is mixed (piggy-backed) in the modeling code; (ii)~the amount of data to be stored may be enormous, and often, a significant part of these data are useless while their collect may consume a significant amount of the computing resources; and (iii)~it is difficult to have confidence in the treatment applied to the data and then make comparisons between studies since each user (model developer) builds its own ad-hoc instrumentation. In particular, we propose OSIF, a new component-based instrumentation framework designed to solve the above mentioned issues. OSIF is based on several mature software engineering techniques and frameworks, such as COSMOS, Fractal and its ADL, and AOP.

Silas De Munck, Kurt Vanmechelen and Jan Broeckhove.
Design and Performance Evaluation of a Conservative Parallel Discrete Event Core for GES

Abstract: The empirical study of large-scale distributed systems often calls for the use of computer simulations as real-world experimentation is too costly or simply infeasible. Computer simulations can also provide results on a much shorter timespan, increasing productivity. Nevertheless, large-scale system simulation can prove to be non-responsive on modern computers, especially when the modeled system has a high level of complexity or when detailed and compute intensive models are used. In order to fully harness the computational power of modern multi-core computer architectures, computer simulations need to execute in a parallel fashion. In this paper we investigate the potential of parallelizing the execution of the Grid Economics Simulator (GES), a Java-based discrete-event simulator that is targeted towards the simulation of distributed systems in general, and economic forms of resource management in grids in particular. We present the design of a parallel continuation-based simulation core that uses a conservative time synchronization protocol. We analyze the performance of the parallel simulation core through synthetic benchmarks. The results of our performance evaluation give a clear insight in the impact of simulation model properties such as event arrival rates, computational workload, remoteness of events, and look-ahead size, on the speedup that can be achieved through parallel execution.

Jean-Luc Béchennec, Mikaël Briday, Sébastien Faucou, Florent Pavin and Fabien Juif.
ViPER: a lightweight approach to the simulation of distributed and embedded software.

Abstract: This paper describes a simulation platform for embedded software named ViPER (Virtual Platform and Environment Runtime). ViPER is oriented toward (but not limited to) systems of the automotive domain. It allows to model and simulate distributed embedded hardware platforms in a scripting environment in order to ease the early development stages of the embedded software.
Each node of the system is virtualized in a process that runs an ad-hoc port of the real-time operating system Trampoline. ViPER manages global time, hardware interrupt and offers a quick and easy way to model hardware devices. In order to close the loop, relevant parts of the environment can be simulated. Once a platform is modeled, ViPER generates description files for each node that ensure the conformance of the hardware abstraction layer to the virtual hardware. ViPER and Trampoline are available as free software.

'David Rieck, Bjoern Schuenemann, Ilja Radusch and Christoph Meinel.
Efficient Traffic Simulator Coupling in a Distributed V2X Simulation Environment

Abstract: For the simulation of all aspects of V2X Communication scenarios, different simulators have to be combined and an interaction among them at runtime of the simulation has to be enabled. Hence, we developed the V2X Simulation Runtime Infrastructure (VSimRTI). It couples discrete event-based simulators, e.g. for communication network, traffic, and V2X application simulation. The flexibility of VSimRTI allows us to vary the composition of integrated simulators depending on the specific requirements of a scenario.  In this paper, we combine both the traffic simulators VISSIM and SUMO. VISSIM is used to get a high accurate simulation of the most interesting region whereas the more efficient traffic simulator SUMO simulates surrounding areas. We show that this simulator coupling reduces the overall simulation time without having a decrease of accuracy.

Yoshinori Koizumi, Yoshifumi Nishida, Yoichi Motomura, Yusuke Miyazaki and Hiroshi Mizoguchi.
Presenting Potential Injury Risk by Biomechanical Simulation Based on Bodygraphic Injury Data and Product Usage Data

Abstract: Injury prevention is one of the most important and urgent issue in children health since the primary cause of death of children is unintentional injuries. Injury prevention requires a technology for making products and environment safe by evaluating their risks. This paper proposes a system for presenting and evaluating potential injury risk using a biomechanical simulation based on bodygraphic injury data collected in hospitals and product usage data collected by sensors. To prove the effectiveness of the proposed system, this paper describes the application of the system to risk analysis of swing type of play equipment in a park. Potential head injury risk around swing equipment was calculated using a physical simulator which consists of a multi-body model, a finite element model of a head, a head injury model, and a children’s play behavior model.

Dalibor Klusacek and Hana Rudová. Alea 2.1 - Job Scheduling Simulator

Abstract: This work describes the Grid and cluster scheduling simulator Alea 2.1 designed for study, testing and evaluation of various job scheduling techniques. This event-based simulator is able to deal with common problems related to the job scheduling like the heterogeneity of jobs, resources, and the dynamic runtime changes such as arrivals of new jobs or resource failures and restarts. Alea 2.1 is based on the popular GridSim toolkit and represents a major extension of the Alea simulator, developed in 2007. The extension covers both improved design, extended functionality as well as improved scalability and higher simulation speed. Finally, new visualization interface was introduced into the simulator. The main part of the simulator is a complex scheduler which incorporates several common scheduling algorithms working either on queue or schedule (plan) based principle. Additional data structures are used to maintain information about resource status, objective
functions and to collect and visualize simulation results. Many typical objectives such as the machine usage, the average slowdown or the average response time are included. The paper concludes with an example of the Alea 2.1 execution using a real-life workload, discussing also the scalability of the simulator.

Michele Fumarola, Mamadou Seck and Alexander Verbraeck.
A component library for simulation based design of container terminals

Abstract: Modeling and simulation in design processes is traditionally used during the analysis of the future system. However, simulation-based design allows the use of modeling and simulation throughout the synthesis phase which offers greater flexibility to quickly compare alternative designs. In case of container terminals, these alternatives are based on different aspects such as layouts, terminal operating systems, and equipments. Container terminals are characterized by a large number of entity types with multiple instances, interacting in various non-trivial ways. A component-based approach makes the construction of a suitable model easier: the designer can focus on the relevant constructs instead of lower level details. However, much effort is needed to achieve compatibility and modularity between the components. DEVS provides the higher level constructs to conceptualize a complex system independently from the underlying implementation. We present a DEVS component library for container terminal design wherein much attention has been put into the conceptual distinction between control and mechanics. This results in a library that can actively support the design process of containers terminals. In this paper, we will present these components and demonstrate the usefulness of the library through a typical design process.

'Nils Aschenbruck, Raphael Ernst, Elmar Gerhards-Padilla and Matthias Schwamborn.
BonnMotion - a Mobility Scenario Generation and Analysis Tool

Abstract: Simulation and emulation are techniques frequently used for performance evaluation of wireless multi-hop networks. If the wireless devices are mobile, the movement patterns of these objects are found to have significant impact on the simulation and emulation results. This is quite obvious as the movements influence the topology of the network.
In this paper we describe and present BonnMotion. BonnMotion is an open-source Java software which creates and analyzes mobility scenarios. It is developed at the University of Bonn, Germany, where it serves as a tool for the investigation of mobile multi-hop network scenario characteristics. The scenarios can also be exported for the network simulators ns-2, GloMoSim/QualNet, COOJA, and MiXiM.

Dimosthenis Pediaditakis, Yuri Tselishchev and Athanassios Boulis.
Performance and scalability evaluation of the Castalia Wireless Sensor Networks simulator

Abstract: Castalia is an open-source simulator for wireless sensor networks and body area networks which is widely used in the academic and research community. This paper presents a basic evaluation study of Castalia, reporting computation time and memory usage for a variety of scenarios/benchmarks. Moreover, key parameters, such as network size, simulation time, fraction of mobile nodes are varied to reveal Castalia’s scalability potential. We discuss our results and explain counterintuitive findings in performance. The results and their explanation can be used by Castalia users as a guide to determine the limits they can push their simulations, as well as to make parameter choices that trade-off accuracy for performance. They also provide an indication of Castalia’s performance capabilities to potential users.

Brandon Aaby, Kalyan Perumalla and Sudip Seal. Efficient Simulation of Agent-Based Models on GPU and Multi-Core Clusters

Abstract: An effective latency-hiding mechanism is presented in the parallelization of agent-based model simulations (ABMS) with millions of agents. The mechanism is designed to accommodate the hierarchical organization as well as heterogeneity of current state-of-the-art parallel computing platforms. We use it to explore the computation vs. communication trade-off continuum available with the deep computational and memory hierarchies of extant platforms and present a novel analytical model of the tradeoff. We describe our implementation and report preliminary performance results on two distinct parallel platforms suitable for ABMS: CUDA threads on multiple, networked graphical processing units (GPUs), and pthreads on multi-core processors. Message Passing Interface (MPI) is used for inter-GPU as well as inter-socket communication on a cluster of multiple GPUs and multi-core processors. Results indicate the benefits of our latency-hiding scheme, delivering as much as over 100-fold improvement in runtime for certain benchmark ABMS application scenarios with several million agents.  This speed improvement is obtained on our system that is already two to three orders of magnitude faster on one GPU than an equivalent CPU-based execution in a popular simulator in Java.  Thus, the overall execution of our current work is over four orders of magnitude faster when executed on multiple GPUs.

Mehdi Mekni.
Hierarchical Path Planning for Situated Agents in Informed Virtual Geographic Environments

Abstract: Multi-Agent Geo-Simulation (MAGS) is a modelling and simulation paradigm which involves a large number of autonomous situated agents evolving in, and interacting with, an explicit description of a geographic environment called a Virtual Geographic Environment (VGE). Path planning in MAGS has to be solved in real time, often under constraints of limited memory and CPU resources. Moreover, the computational cost of path planing increases in complex and large scale VGEs. In addition, most current planners only provide agents with obstacle-free paths and do not take into account the environments' topologic and semantic characteristics nor the agents' capabilities. In this paper, we propose a novel approach to build a semantically-enhanced and geometrically-accurate VGE called an Informed VGE (IVGE). We also present a hierarchical path planning algorithm which takes advantage of this IVGE's rich description in order to provide autonomous situated agents with plausible paths with respect to both the environment's and the agents' characteristics.

Olivia Brickley, Martin Koubek, Susan Rea and Dirk Pesch.
A Comprehensive Simulation Environment for CALM-based Cooperative Vehicular Systems

Abstract: The concept of Intelligent Transportation Systems (ITS) presents new R&D challenges in the transportation and ICT sectors and is currently receiving considerable interest from the research community. The primary objective of ITS is the creation of advanced road traffic systems for improved traffic safety, efficiency, and travelling comfort. Applications such as trip planning, automatic tolling and emergency warnings, among others, are envisaged in a system which can potentially reform modern transportation. Basic vehicle and roadside infrastructure collaboration allows an increase in efficiency and safety and acts as a foundation for an extensive application set to achieve these ITS goals. The use of software tools to simulate the behaviour of a network, and then analysing the effect of various parameters on the network performance, is a crucial task for such new technologies' application development and implementation. Currently, since neither infrastructure nor communications capabilities exist in vehicles beyond small scale prototypes, computer simulation is the only viable option in evaluation of potential ITS solutions. This paper presents a comprehensive simulation environment for CALM-based cooperative vehicular systems. Using the OPNET modeler simulation tool, a number of elements necessary for accurate emulation of the complex cooperative vehicular network are identified and addressed. Important areas of consideration include vehicle mobility, communications channel behaviour, application structure and RSU and OBU device modelling to accurately emulate the envisaged ITS concept.

Mohammed Muqsith and Hessam Sarjoughian.
Modeling and Simulation of Service Based Software Systems: A Co-design Approach

Abstract: The adoption of the Service Oriented Architecture (SOA) as the foundation for developing a new generation of software systems poses important challenges in system design. While simulation as a methodology serves a principal role in design, there is a growing recognition that simulation of Service Based Software Systems (SBS) requires modeling capabilities beyond those that are developed for the traditional distributed software systems. In this paper, a novel approach supporting DEVS simulation modeling of not only the services consistent with Service-Oriented Computing (SOC) concepts and principles, but also the networked hardware components on which services must execute on. The resulting software/hardware co-design called SOC-DEVS has been realized using an extended version of the SOA-compliant DEVS simulator. An example model for a voice communication system is developed to illustrate the kind of hardware and software components that can be modeled and simulated. Future research in the larger context of adaptable SBS is also presented.

Kalyan Perumalla.
µn: A Highly Scalable and Transparent System for Simulating MPI Programs

Abstract: µπ is a highly scalable, transparent system for predicting the performance of parallel programs.  Performance can be investigated by executing actual applications on customized configurations of hypothetical parallel machines.  The level of detail can be varied for application behavior as well as machine characteristics.  Unique features of µπ are repeatability of execution, scalability to very large number of processing elements, portability of the system to a wide variety of platforms, and ease of experimentation with scientific applications with source-code.  The design of µπ supports experimentation using thousands of real cores to predict the performance of applications using several fold as many virtual cores as real cores.  Low slowdowns are observed, due to the scalability and efficiency of the underlying simulator, µsik.

Özer Özdikiş, Umut Durak and Halit Oguztüzün.
Tool Support for Transformation from OWL Ontology to HLA Object Model

Abstract: Designing simulation architectures based on domain models is a promising approach. Tools to support transformation of formalized domain models to design models are essential. Ontologies offer a way of formally specifying the domain knowledge. We adopt a user-guided approach to model transformation, where the source is an OWL ontology and the target is an HLA Object Model, in particular, a federation object model (FOM).  This paper presents a flexible transformation tool that enables the user to define transformations by using mappings from OWL constructs to HLA Object Model Template (OMT) constructs. The overall objective is to facilitate ontology-based model-driven development in simulation domain.

Davide Cangelosi.
SSALeaping: Efficient Leap Condition Based Direct Method Variant for the Stochastic Simulation of Chemical Reacting Systems

Abstract: The tau-leaping methods are very promising solutions for accelerating stochastic simulation of well-stirred chemically reacting systems. In this paper, we propose a new stochastic simulation algorithm variant, called SSAL, which lays in the middle between the Gillespie's Direct Method and a tau-leaping approach. Essentially, SSAL works as a standard Direct Method. However, it uses the typical Leap Condition to incrementally build leaps, avoiding at the same time the risk of getting into negative populations. We compare SSAL with one of the most known and efficient tau-leaping method, called Modified tau-leaping. We provide for both of them a detailed theoretical asymptotic analysis and some practical tests using three realistic models.

Esa Hyytiä, Lauri Häme, Aleksi Penttinen and Reijo Sulonen.
Simulation of a large scale dynamic pickup and delivery problem

Abstract: We study a variant of Dynamic Vehicle Routing Problem with Pickups and Deliveries where a vehicle is allocated to each service (i.e., trip) request immediately upon the arrival of the request. Solutions to this problem can be characterized as dynamic policies that define how each customer is handled by operating a fleet of vehicles. Evaluation of such policies is beyond the grasp of analytical studies and requires extensive simulations. We present an efficient and modular simulation tool developed for studying the performance of a large scale system with different policies under given trip arrival process. Numerical and analytical observations on the simulation model are utilized to provide guidelines for solving the routing problem efficiently, and to support the validation of the simulation results. Application of the developed framework is demonstrated by several numerical examples including a policy parameter optimization.

George Riley.
Invited talk: the ns-3 project; where we are and where we are heading

Abstract: Since the initial effort to design and implement the new ns-3 network simulator began in Summer 2006, the project has made significant progress towards its initial goals. In this talk, we will discuss some of the stated goals, discuss the design decisions to meet those goals, and present the current capabilities of the ns-3 tool. Then we will show a roadmap for the immediate and long-term future plans to ensure ns-3 will continue to thrive and attract both users and contributors.