SIMULATION

Processor concepts, implementation details, and performance analysis are fundamental in computer architecture education, and MIPS (microprocessor without interlocked pipeline stages) processor designs are used by many universities in teaching the subject. In this paper we present a MIPS32 processor simulator, which enriches students’ learning and instructors’ teaching experiences. A family of single-cycle, multi-cycle, and pipeline processor models for the MIPS32 architecture are developed according to the parallel Discrete Event System Specification (DEVS) modeling formalism. A collection of elementary sequential and combinational model components along with the processor models are implemented in DEVS-Suite. The simulator supports multi-level model abstractions, register-transfer level animation, performance data collection, and time-based trajectory observation. These features, which are partially supported by a few existing simulators, enable important structural and behavioral details of computer architectures to be described and understood. The MIPS processor models can be reused and systematically extended for modeling and simulating other MIPS processors.

OMNeT++ is a discrete event simulation environment primarily designed for communication networks. In this paper we present an approach to enable OMNeT++ to simulate complex hierarchical process chains. Process chains are a common modeling paradigm in the logistics area for analysis and optimization, and have been used intensely in many practical applications. Their evaluation is supported by the ProC/B toolset, a collection of software tools for modeling, analysis, validation and optimization of process chains. Here we describe how OMNeT++ has been integrated as a new simulation engine into the toolset. The integration has to overcome some core problems to allow a smooth interaction between OMNeT++ and the other tools: in particular, the OMNeT++ model description of the logistics network should be kept manageable, it should reflect the entire model structure and non-standard performance figures, being relevant for an economic evaluation should be ascertainable in order to satisfy the specific needs of the application area. This paper highlights the main steps of the automatic transformation of a hierarchical process chain model into a hierarchical model in OMNeT++. Furthermore, we show how the transformation has been validated and how detailed performance figures can be evaluated with OMNeT++.

NeSSi (network security simulator) is a novel network simulation tool which incorporates a variety of features relevant to network security distinguishing it from general-purpose network simulators. Its capabilities such as profile-based automated attack generation, traffic analysis and support for detection algorithm plug-ins allow it to be used for security research and evaluation purposes. NeSSi has been successfully used for testing intrusion detection algorithms, conducting network security analysis and developing overlay security frameworks. NeSSi is built upon the agent framework JIAC, resulting in a distributed and extensible architecture. In this paper, we provide an overview of the NeSSi architecture as well as its distinguishing features and briefly demonstrate its application to current security research projects.

We present an end-to-end simulation framework that is capable of simulating High-Performance Computing (HPC) systems with hundreds of thousands of interconnected processors. The tool applies discrete event simulation and is driven by real-world application traces. It provides a semantically correct replay of MPI application traces and maintains reasonable simulation details of both the processors in general and the interconnection network in particular. Among other things, it features several interconnection network topologies, flexible routing schemes, arbitrary application task placement, point-to-point statistics collection, and data visualization. With a few case studies, we demonstrate the usefulness of this tool for assisting high-level system design as well as for performance projection and application tuning of future HPC systems.

Epidemiology instructors are collaborating with computer scientists to construct network-based simulations to recreate infectious disease transmission dynamics and to examine intervention strategy efficacies. Here we propose an architecture based on demographic and geographic properties to support the learning efforts of undergraduate students and novice researchers, and describe our simulations of HIV, SARS, and influenza transmission dynamics in Taiwan. Our findings are offered to support the construction of new network-based epidemic simulations.

In this paper we present a methodological approach designed to automate the decision-making in logistic systems, with deterministic time, by solving optimization problems. The Colored Petri Net (CPN) formalism has been used as a base to develop a methodology that integrates the features of operational research, artificial intelligence and simulation fields. At the same time, it combines the modeling of discrete event systems with simulation, analysis and system optimization, transforming a conceptual model into a simulation model, and a decision problem into a search problem. The use of the CPN formalism has allowed the integration of all of these different research fields into a unique decision support tool.