GARDSim - A GPS Receiver Simulation Environment for Integrated Navigation System Development and Analysis

Airservices Australia has recently proposed the use of a Ground-based Regional Augmentation System (GRAS) to improve the safety of using the NAVSTAR Global Positioning System (GPS) in aviation. The GRAS Airborne Receiver Development project (GARD) is being conducted by QUT in conjunction with Airservices Australia and GPSat Systems. The aim of the project is to further enhance the safety and reliability of GPS and GRAS by incorporating smart sensor technology including advanced GPS signal processing and Micro-Electro-Mechanical-Sensor (MEMS) based inertial components. GARDSim is a GPS and GRAS receiver simulation environment which has been developed for algorithm development and analysis in the GARD project. GARDSim is capable of simulating any flight path using a given aeroplane flight model, simulating various GPS, GRAS and inertial system measurements and performing high integrity navigation solutions for the flight. This paper discusses the architecture and capabilities of GARDSim. Simulation results will be presented to demonstrate the usefulness of GARDSim as a simulation environment for algorithm development and evaluation

Performance analysis of cloud-based cve communication architecture in comparison with the traditional client server, p2p and hybrid models

Gital et al. (2014) proposed a cloud based communication architecture for improving efficiency of collaborative virtual environment (CVE) systems in terms of Scalability and Consistency requirements. This paper evaluates the performance of the proposed CVE architecture. The metrics use for the evaluation is response time. We compare the cloud-based architecture to the traditional client server and peer-2–peer (P2P) architecture. The comparison was implemented in the CVE systems. The comparative simulation analysis of the results suggested that the CVE architecture based on cloud computing can significantly improve the performance of the CVE system

An evaluation of a contract management simulation game for architecture students

Architects are currently grappling to exploit new forms of communication made possible with developments in internet communication. At the same time, the construction industry is in a state of flux as novel project management systems are being introduced. Students need to understand the first principles of project management within the context of our changing environment. One of the best ways for students to learn about the legalities of the construction process is through role play and simulation but there is a Catch 22. Unless students have a basic understanding of project management, the contractual process can be confusing and intimidating. Even fifth and sixth year architecture students are reluctant to ask practitioners questions for fear of appearing ignorant. This paper presents an evaluation of the cost and benefits of a web-based simulation game to deliver the Architecture studies curriculum. The webbased game allows students to critically observe the transformation of designs into buildings through the exploration of the contract management process. A questionnaire survey was used to assess how the computer simulation operates as a group exercise, how it compares with more traditional approaches and the best and worst features of the web-based system. The students found the game to be practical, enjoyable, motivating and effective in stimulating the learning process. The benefits of the web-based game were also found to outweigh the costs, thus providing support for its use as an active learning tool in Architectural Education

Vehicular Fog Computing Enabled Real-time Collision Warning via Trajectory Calibration

Vehicular fog computing (VFC) has been envisioned as a promising paradigm for enabling a variety of emerging intelligent transportation systems (ITS). However, due to inevitable as well as non-negligible issues in wireless communication, including transmission latency and packet loss, it is still challenging in implementing safety-critical applications, such as real-time collision warning in vehicular networks. In this paper, we present a vehicular fog computing architecture, aiming at supporting effective and real-time collision warning by offloading computation and communication overheads to distributed fog nodes. With the system architecture, we further propose a trajectory calibration based collision warning (TCCW) algorithm along with tailored communication protocols. Specifically, an application-layer vehicular-to-infrastructure (V2I) communication delay is fitted by the Stable distribution with real-world field testing data. Then, a packet loss detection mechanism is designed. Finally, TCCW calibrates real-time vehicle trajectories based on received vehicle status including GPS coordinates, velocity, acceleration, heading direction, as well as the estimation of communication delay and the detection of packet loss. For performance evaluation, we build the simulation model and implement conventional solutions including cloud-based warning and fog-based warning without calibration for comparison. Real-vehicle trajectories are extracted as the input, and the simulation results demonstrate that the effectiveness of TCCW in terms of the highest precision and recall in a wide range of scenarios

Applications of agent architectures to decision support in distributed simulation and training systems

This work develops the approach and presents the results of a new model for applying intelligent agents to complex distributed interactive simulation for command and control. In the framework of tactical command, control communications, computers and intelligence (C4I), software agents provide a novel approach for efficient decision support and distributed interactive mission training. An agent-based architecture for decision support is designed, implemented and is applied in a distributed interactive simulation to significantly enhance the command and control training during simulated exercises. The architecture is based on monitoring, evaluation, and advice agents, which cooperate to provide alternatives to the dec ision-maker in a time and resource constrained environment. The architecture is implemented and tested within the context of an AWACS Weapons Director trainer tool. The foundation of the work required a wide range of preliminary research topics to be covered, including real-time systems, resource allocation, agent-based computing, decision support systems, and distributed interactive simulations. The major contribution of our work is the construction of a multi-agent architecture and its application to an operational decision support system for command and control interactive simulation. The architectural design for the multi-agent system was drafted in the first stage of the work. In the next stage rules of engagement, objective and cost functions were determined in the AWACS (Airforce command and control) decision support domain. Finally, the multi-agent architecture was implemented and evaluated inside a distributed interactive simulation test-bed for AWACS Vv\u27Ds. The evaluation process combined individual and team use of the decision support system to improve the performance results of WD trainees. The decision support system is designed and implemented a distributed architecture for performance-oriented management of software agents. The approach provides new agent interaction protocols and utilizes agent performance monitoring and remote synchronization mechanisms. This multi-agent architecture enables direct and indirect agent communication as well as dynamic hierarchical agent coordination. Inter-agent communications use predefined interfaces, protocols, and open channels with specified ontology and semantics. Services can be requested and responses with results received over such communication modes. Both traditional (functional) parameters and nonfunctional (e.g. QoS, deadline, etc.) requirements and captured in service requests

A Multi Agent System for Flow-Based Intrusion Detection Using Reputation and Evolutionary Computation

The rising sophistication of cyber threats as well as the improvement of physical computer network properties present increasing challenges to contemporary Intrusion Detection (ID) techniques. To respond to these challenges, a multi agent system (MAS) coupled with flow-based ID techniques may effectively complement traditional ID systems. This paper develops: 1) a scalable software architecture for a new, self-organized, multi agent, flow-based ID system; and 2) a network simulation environment suitable for evaluating implementations of this MAS architecture and for other research purposes. Self-organization is achieved via 1) a reputation system that influences agent mobility in the search for effective vantage points in the network; and 2) multi objective evolutionary algorithms that seek effective operational parameter values. This paper illustrates, through quantitative and qualitative evaluation, 1) the conditions for which the reputation system provides a significant benefit; and 2) essential functionality of a complex network simulation environment supporting a broad range of malicious activity scenarios. These results establish an optimistic outlook for further research in flow-based multi agent systems for ID in computer networks

Application of Executable Architectures in Early Concept Evaluation

This research explores use of executable architectures to guide design decisions in the early stages of system development. Decisions made early in the system development cycle determine a majority of the total lifecycle costs as well as establish a baseline for long term system performance and thus it is vital to program success to choose favorable design alternatives. The development of a representative architecture followed the Architecture Based Evaluation Process as it provides a logical and systematic order of events to produce an architecture sufficient to document and model operational performance. In order to demonstrate the value in the application of executable architectures for trade space decisions, three variants of a fictional unmanned aerial system were developed and simulated. Four measures of effectiveness (MOEs) were selected for evaluation. Two parameters of interest were varied at two levels during simulation to create four test case scenarios against which to evaluate each variant. Analysis of the resulting simulation demonstrated the ability to obtain a statistically significant difference in MOE performance for 10 out of 16 possible test case-MOE combinations. Additionally, for the given scenarios, the research demonstrated the ability to make a conclusive selection of the superior variant for additional development

Performance Evaluation of Impluse Radio Ultra Wide Band Wireless Sensor Networks

This paper presents a performance evaluation of Wireless Sensor Networks (WSN) based on Impulse Radio Ultra Wideband (IR-UWB) over a new simulation platform developed for this purpose. The simulation platform is built on an existing network simulator: Global Mobile Information System Simulator (GloMoSim). It mainly focuses on the accurately modeling of IR-UWB PHYsical (PHY) and Medium Access Control (MAC) layer. Pulse collision is modeled according to the used time hopping sequence (THS) and the pulse propagation delay in order to increase the simulation fidelity. It also includes a detection and identification application based on a new sensing channel and new sensor device models. The proposed architecture is generic so it can be reused for any simulation platform. The performance evaluation is based on one of the typical WSN applications: local area protection, where sensor nodes are densely scattered in an access regulated area in order to detect, identify and report non authorized accesses to a base station for analysis. Two networks topologies using different protocol stacks are investigated. Their performance evaluation is presented in terms of reliability and latency

The NASA Lewis integrated propulsion and flight control simulator

A new flight simulation facility was developed at NASA-Lewis. The purpose of this flight simulator is to allow integrated propulsion control and flight control algorithm development and evaluation in real time. As a preliminary check of the simulator facility capabilities and correct integration of its components, the control design and physics models for a short take-off and vertical landing fighter aircraft model were shown, with their associated system integration and architecture, pilot vehicle interfaces, and display symbology. The initial testing and evaluation results show that this fixed based flight simulator can provide real time feedback and display of both airframe and propulsion variables for validation of integrated flight and propulsion control systems. Additionally, through the use of this flight simulator, various control design methodologies and cockpit mechanizations can be tested and evaluated in a real time environment