Scalable Simulation Environment Research Articles

Autonomous Identification and Optimal Selection of Popular Smart Vehicles for Urban Sensing—An Information-Centric Approach

Today, vehicles are becoming powerful sensor platforms capable of collecting, storing, and sharing large amounts of sensory data by constant monitoring of urban streets. It is quite challenging to upload such data from all vehicles to the infrastructure due to limited bandwidth resources and high cost. This invokes the need to identify the appropriate vehicles, important for different urban sensing tasks based on their natural mobility. This paper address this problem of leveraging the self-decision making ability of a “smart vehicle” to measure its relative importance in the network. To do so, we present InfoRank as an information-centric algorithm for a vehicle to first autonomously rank different location-aware information. It then uses the information importance along its mobility pattern to find its importance in the network. We also present a selection algorithm to find the best ranked vehicles for urban sensing and vicinity monitoring to achieve a desired coverage within a limited budget. Our vehicle ranking system is the first step toward identifying the best information hubs to be used in the network for the efficient collection, storage, and distribution of urban sensory information. We evaluate InfoRank under a scalable simulation environment using realistic vehicular mobility traces. Results show that the proposed ranking system efficiently identified socially important vehicles in comparison to other ranking schemes.

A Scalable Modeling and Simulation Environment for Chemical Gas Emergencies

To reflect an evacuation process using a conventional agent-based approach to model human movement under chemical gas exposure, a scalable and hybrid agent-based simulation (ABS) model incorporates an interactive computational fluid dynamics (CFD) gas flow model. To embrace the hybrid ABS model, CFD model, and models for countermeasure in various domains, a scalable runtime infrastructure (RTI)-based simulation environment is also proposed. This environment provides a simulator-level interface to integrate a continuous and discrete-event simulator into the RTI by resolving data/event interaction and time synchronization among heterogeneous simulation models. The authors successfully interoperated the hybrid ABS model, interactive CFD model, control center model, and gas sensor model to evaluate the countermeasures in the proposed environment. As a case study, they applied a 3D-based virtual training engine as a standalone modeling and simulation element to show the scalability of the proposed environment.

Complex fluid simulations with the parallel tree-based Lattice Boltzmann solver Musubi

We present the open source Lattice Boltzmann solver Musubi. It is part of the parallel simulation framework APES, which utilizes octrees to represent sparse meshes and provides tools from automatic mesh generation to post-processing. The octree mesh representation enables the handling of arbitrarily complex simulation domains, even on massively parallel systems. Local grid refinement is implemented by several interpolation schemes in Musubi. Various kernels provide different physical models based on stream-collide algorithms. These models can be computed concurrently and can be coupled with each other. This paper explains our approach to provide a flexible yet scalable simulation environment and elaborates its design principles and implementation details. The efficiency of our approach is demonstrated with a performance evaluation on two supercomputers and a comparison to the widely used Lattice Boltzmann solver Palabos.

Economic application of virtual commissioning to mechatronic production systems

The interaction of heterogenous control hard and software plays a key role in enabling mechatronic production systems to become flexible and agile systems. Nevertheless, control software engineering still tends to be the last step within the development process. To a large extent it is carried out during the commissioning phase of the production ramp-up. On the first hand this leads to a loss of time and quality as well as to a loss of reputation and future orders on the second hand. A method that is referred to as Virtual Commissioning tries to overcome this situation. The aim is to enable control software engineering to, both take over the initiative in system design and to perform important activities earlier in the design process of production equipment. In this paper, the technological and economical scalability of Virtual Commissioning is analyzed. Based on the analysis, a technical concept for a scalable simulation environment is presented. The paper concludes with a new method for the economic application of Virtual Commissioning.

SimDS

Design of a distributed transaction processing system is a complex process. The paper describes the design and implementation of a general purpose scalable simulation environment (SimDS) for designing and evaluating the performance of distributed transaction processing systems. SimDS is a distributed simulation system where each data server is implemented as a separate process that communicates with each other through user datagram protocol. The paper describes the features of SimDS including various design policies that can be modeled by the system. It also discusses different design issues that one needs to consider in the implementation of a distributed simulation environment. The paper concludes with some test examples where SimDS was used to simulate different configurations of a real-time transaction processing system.