real-time image transmission is crucial to an emerging class of distributed embedded systems operating in open network environments. Examples include avionics mission replanning over Link-16, security systems based on...
详细信息
real-time image transmission is crucial to an emerging class of distributed embedded systems operating in open network environments. Examples include avionics mission replanning over Link-16, security systems based on wireless camera networks, and online collaboration using camera phones. Meeting image transmission deadlines is a key challenge in such systems due to unpredictable network conditions. In this paper, we present CAMRIT, a Control-based Adaptive Middleware framework for real-time Image Transmission in distributedreal-time embedded systems. CAMRIT features a distributed feedback control loop that meets image transmission deadlines by dynamically adjusting the quality of image tiles. We derive an analytic model that captures the dynamics of a distributed middleware architecture. A control-theoretic methodology is applied to systematically design a control algorithm with analytic assurance of system stability and performance, despite uncertainties in network bandwidth. Experimental results demonstrate that CAMRIT can provide robust real-time guarantees for a representative application scenario.
We present in this paper a novel load balancing and rescheduling approach based on the concept of the Sandpile cellular automaton: a decentralized multi-agent system working in a critical state at the edge of chaos. O...
详细信息
We present in this paper a novel load balancing and rescheduling approach based on the concept of the Sandpile cellular automaton: a decentralized multi-agent system working in a critical state at the edge of chaos. Our goal is providing fairness between concurrent job submissions in highly parallel and distributed environments such as currently built cloud computing systems by minimizing slowdown of individual applications and dynamically rescheduling them to the best suited resources. The algorithm design is experimentally validated by a number of numerical experiments showing the effectiveness and scalability of the scheme in the presence of a large number of jobs and resources and its ability to react to dynamic changes in realtime. (C) 2016 Elsevier B.V. All rights reserved.
The networked workstation system is one of the commonly used Virtual Environment (VE) hardware platforms. In this paper we discuss distributed graphics support for implementation of VE systems and present an experimen...
详细信息
The networked workstation system is one of the commonly used Virtual Environment (VE) hardware platforms. In this paper we discuss distributed graphics support for implementation of VE systems and present an experimental environment called DGPSE+. It provides four kinds of consistency control methods: mutual exclusion, centralized controller, sequential ordering, and distributed lock. To meet the real-time requirement of VE systems, DGPSE+ contains a set of parallel graphics rendering algorithms with different computation requirement. A distributed stereoscopic graphics rendering is also included. It can find out idle or near idle workstations to execute the parallel algorithms. DGPSE+ has advantages such as multiple consistency control mechanisms and powerful graphics rendering support capability. (C) 1996 Elsevier Science Ltd
After thoroughly reading the problem statement on the air defense system I asked myself whether the problem statement was clear and unambiguous. In order to test the internal quality and consistency of the problem sta...
详细信息
The Development Framework translates application-specific system specifications into parallel, hard real-time implementations using methods that are both familiar to developers and optimal for the application.
The Development Framework translates application-specific system specifications into parallel, hard real-time implementations using methods that are both familiar to developers and optimal for the application.
This paper discusses the requirements for the modeling of distributedreal-timesystems, both from an engineering and a reengineering point of view. A suitable extension of the object-oriented paradigm with execution ...
详细信息
To guarantee the delivery of real-time messages before their deadline, a real-time channel or connection must be established before the transmission of any message belonging to the connection. During this channel esta...
详细信息
To guarantee the delivery of real-time messages before their deadline, a real-time channel or connection must be established before the transmission of any message belonging to the connection. During this channel establishment phase, one must first select a route between the source and destination of this channel and then reserve sufficient resources along this route so that the worst-case end-to-end delay over the selected route may not exceed the user-specified delay bound. We propose an efficient distributed route selection scheme that is guaranteed to find a "qualified" route, if any, satisfying the performance requirement of the requested channel without compromising any of the existing guarantees. The proposed scheme can also eliminate the common reliability/performance bottleneck of a centralized route selection scheme while improving efficiency over the centralized and other distributed schemes. Although the proposed solution starts with searching all possible routes in parallel, it prunes infeasible routes quickly, and its worst-case operational overhead is shown to be only a linear function of the number of links in the network. Several examples and simulation results are presented to demonstrate the effectiveness of the proposed distributed route selection scheme as compared to sequential route-search schemes.
This paper describes a visual tool for developing real-time control software for distributed industrial systems. The aim of this project currently in progress, is to obtain a visual programming environment which integ...
详细信息
This paper describes a visual tool for developing real-time control software for distributed industrial systems. The aim of this project currently in progress, is to obtain a visual programming environment which integrates both the advantages of object-oriented modelling for the design and simulation of systems and the power of modern distributed control systems (i.e. computers with real-time operating systems interconnected by means of industrial real-time networks). To bridge the gap between the object-oriented system model and the implementation level, at which we have multiple parallel tasks running on a network, sequential function charts (SFCs) are used as a standard formalism [12,16] for the description of system dynamics and control software programming. (C) 1999 Elsevier Science B.V. All rights reserved.
This at-tide aims at introducing SYD, a tool for the generation of time-stamps synchronized with the Universal time Coordinate: the implementation includes an NTP client and is written in Java(1). Possible application...
详细信息
ISBN:
(纸本)0769500595
This at-tide aims at introducing SYD, a tool for the generation of time-stamps synchronized with the Universal time Coordinate: the implementation includes an NTP client and is written in Java(1). Possible applications include (but are not limited to) the measurement of the performance of distributed applications, their debugging, and Me implementation of real-time requirements in distributedsystems. The features that characterize SYD are its portability across platforms, the low cost in terms of network overhead, and the absence of interference with other applications running on the same host (SYD does not synchronize the system clock!);In this paper, we prove that the choice of Java does impact on the performance of the tool, when compared with an equivalent application written inC. SYD is available on the Web as public domain software.
暂无评论