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ieee international conference on Computational Science and Engineering, CSE

作者： Denis R. Ogura Edson T. Midorikawa Laboratory of Architecture and High Performance University of São Paulo Sao Paulo Brazil

Cloud computing is one of the hottest topics researched today, with the objective of taking advantage of data center computational resources. Hardware and software virtualization make the environment scalable, redundant, and lower cost. this paper intends to characterize scientific and transactional applications in Cloud infrastructures IaaS, identifying the best virtual machine configuration in terms of the optimal processor allocation for executing parallel and distributed applications. through the study, it was achieved 3 times improvements of the elapse time on scientific and transactional applications.

关键词： Cloud computing Benchmark testing Databases Hardware File systems Virtual machining Computer architecture

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Optimal Scheduling of Urgent Preemptive Tasks

Optimal Scheduling of Urgent Preemptive Tasks

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ieee international conference on embedded and real-time computing systems and applications (RTCSA)

作者： Stefan Andrei Albert Cheng Martin Rinard Lawrence Osborne Department of Computer Science Lamar University Beaumont TX USA Department of Electrical Engineering & Computer Science Massachusetts Institute of Technology Cambridge MA USA Department of Computer Science University of Houston Houston USA

Tasks' scheduling has always been a central problem in the embedded real-time systems community. As in general the scheduling problem is NP-hard, researchers have been looking for efficient heuristics to solve the scheduling problem in polynomial time. One of the most important scheduling strategies is the Earliest Deadline First (EDF). It is known that EDF is optimal for uniprocessor platforms for many cases, such as: non-preemptive synchronous tasks(i.e., all tasks have the same starting time and cannot be interrupted), and preemptive asynchronous tasks (i.e., the tasks may be interrupted and may have arbitrary starting time). However, Mok showed that EDF is not optimal in multiprocessor platforms. In fact, for the multiprocessor platforms, the scheduling problem is NP-complete in most of the cases where the corresponding scheduling problem can be solved by a polynomial-time algorithm for uniprocessor platforms. Coffman and Graham identified a class of tasks for which the scheduling problem can be solved by a polynomial time algorithm, that is, two-processor platform, no resources, arbitrary partial order relations, and every task is nonpreemptive and has a unit computation time. Our paper introduces a new non-trivial and practical subclass of tasks, called urgent tasks. Briefly, a task is urgent if it is executed right after it is ready or it can only wait one unit time after it is ready. Practical examples of embedded real time systems dealing with urgent tasks are all modern building alarm systems, as these include urgent tasks such as `checking for intruders', `sending a warning signal to the security office',`informing the building's owner about a potential intrusion', and so on. By using propositional logic, we prove a new result in schedulability theory, namely that the scheduling problem for asynchronous and preemptive urgent tasks can be solved in polynomial time.

关键词： Processor scheduling Optimal scheduling Scheduling Polynomials Schedules Complexity theory real time systems

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Context-Based Analysis of System Execution Traces for Validating Distributed real-time and embedded System Quality-of-Service Properties

Context-Based Analysis of System Execution Traces for Valida...

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ieee international conference on embedded and real-time computing systems and applications (RTCSA)

作者： James H. Hill Department of Computer and Information Science Indiana University Indianapolis IN USA

System execution traces are useful artifacts for capturing distributed system behavior and validating quality-of-service (QoS) properties, such as end-to-end response time, throughput, and scalability. Although system execution traces assist in validating QoS properties, system execution traces are very dense. this is because system execution traces capture a system's complete behavior and execution in its target environment, which can consist of many components deployed across many hosts that execute for long periods of time. It therefore can be hard for distributed system testers to effectively analyze different views of QoS properties using system execution traces and/or pinpoint performance bottlenecks that need to be resolved. this paper provides two contributions on validating distributed system QoS properties. First, this paper presents Aspects for System Execution Traces (AsSET), which is a join point model for applying aspects to system execution traces and enabling context-based analysis of system execution traces. Secondly, it shows how applying AsSET to a representative enterprise distributed system can improve QoS analytical capabilities for distributed system testers. the tools and techniques discussed in this paper have been realized in an open-source system execution modeling tool named CUTS, which is currently used on several industry-related projects.

关键词： Quality of service Context Data mining time factors Context modeling Data models Software

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Detecting, Locating, and Tracking Hacker Activities within a WLAN Network

Detecting, Locating, and Tracking Hacker Activities within a...

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ieee international conference on embedded and real-time computing systems and applications (RTCSA)

作者： Kevin C. Shum Joseph K. Ng Department of Computer Science Hong Kong Baptist University Hong Kong China

With a good location estimation integrated into a Wi-Fi surveillance system, system administrator can closely monitor the network traffic as well as the behavior of the mobile users. Hence, there is a growing demand to have a quick and efficient way to indentify a specific group of people, or devices or asset within a controlled wireless network. In our proposed system, all the Wi-Fi traffic and information especially the MAC addresses and RSSI from the mobile clients (i.e. Wi-Fi devices) can be sniffed by an open-source Wi-Fi access point (AP) with custom-made embedded software program and without pre-loading any client program on the mobile user devices. these sniffed information is then analyzed and stored in a database which will help network administrator to monitor the wireless network for surveillance purpose and security concerns. In summary, this paper proposes a wireless LAN system that can detect, locate and track down wireless communication within the system by modifying the embedded software in off-the-shelf WLAN APs. Experiment results have shown that abnormal wireless activities can be detected and by our signal strength based localization algorithm, positions of these wireless mobile devices can be identified and be tracked within meters inside our WLAN system.

关键词： Wireless LAN Wireless communication Mobile communication Mobile handsets Estimation Communication system security ieee 802.11 Standards

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Global Reliability-Aware Power Management for Multiprocessor real-time systems

Global Reliability-Aware Power Management for Multiprocessor...

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ieee international conference on embedded and real-time computing systems and applications (RTCSA)

作者： Xuan Qi Dakai Zhu Hakan Aydin Department of Computer Science University of Texas San Antonio San Antonio TX USA Department of Computer Science George Mason University Fairfax VA USA

Recently, the negative effect of the popular power management technique Dynamic Voltage and Frequency Scaling (DVFS) on the system reliability has been identified. As a result, various reliability-aware power management (RAPM) schemes have been studied for uniprocessor real-time systems. In this paper, we investigate global scheduling-based RAPM (G-RAPM) schemes for a set of frame-based real-time tasks running on a homogeneous multiprocessor system. An important dimension of the problem is how to select the appropriate subset of tasks for energy and reliability management (i.e., schedule a recovery for each selected task and scale down their executions). We show that making this decision optimally (i.e., the static G-RAPM problem) is NP-hard. then we propose two efficient G-RAPM heuristics, which rely on local and global task selections, respectively. Moreover, to reclaim dynamic slack generated at runtime, we extend the slack-sharing based global dynamic power management scheme to the reliability-aware settings. the proposed schemes are evaluated through extensive simulations. the results show that our static G-RAPM heuristics can preserve system reliability while achieving significant energy savings (within 3% of an upper bound for most cases). Moreover, G-RAPM with global task selection provides better opportunities for dynamic slack reclamation and up to 15% more energy savings can be obtained at runtime compared to that of local task selection.

关键词： Reliability real time systems Transient analysis Schedules time frequency analysis Energy consumption Multiprocessing systems

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An intelligent on-line route guide system in a fleet

An intelligent on-line route guide system in a fleet

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international conference on Intelligent Transportation

作者： Pin-Yung Chen Ya-Wen Shih Shih-Hung Chang Yi-Hsuan Hung Industrial Technology and Research Institute Hsinchu Taiwan National Tsing Hua University Taiwan National Taiwan Normal University Taipei Taiwan

this paper presents an intelligent on-line route guide system using leader-following concept in a fleet. In order to achieve the concept of a car leader leading other car members in a fleet, we establish their contact through the real-time GPS position data with a 3G wireless communication. Every car members can obtain the real-time positions of the leader car and other car members. then, the corresponding following route can be computed and shown by a client device in the car. Finally, a dynamic and real-time following function in a motorcade is achieved. the experimental results are provided to verify the reliability and the real-time function of this proposed concept. the most impressive advantage is that the proposed concept can provide more convenience in driving and can be easily extended to other applications such as a stolen-car searching system, a dynamic public bus regulation system, a collision prevention system, etc..

关键词： Global Positioning System Software Servers Vehicles real time systems Monitoring

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QAFT: A QoS-Aware Fault-Tolerant Scheduling Algorithm for real-time Tasks in Heterogeneous systems

QAFT: A QoS-Aware Fault-Tolerant Scheduling Algorithm for Re...

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ieee international conference on Computational Science and Engineering, CSE

作者： Xiaomin Zhu Jianghan Zhu Manhao Ma Dishan Qiu Science and Technology on Information Systems Engineering Laboratory National University of Defense Technology Changsha China

Fault-tolerant scheduling, effective means of improving system reliability, plays a significant role in some mission-critical applications. Although extensive fault-tolerant scheduling algorithms have been proposed for real-time tasks in distributed systems, quality of service (QoS) requirements demanded by mission-critical tasks have not been taken into consideration. this paper proposes a QoS-aware fault-tolerant scheduling algorithm named QAFT that can tolerate one processor's permanent failure at one time instant for real-time tasks with QoS needs in heterogeneous systems. QAFT strives to advance the start time of primary copies and delay the start time of backup copies to make backup copies adopt passive execution scheme or decrease the simultaneous execution time of the primary and backup copies of a task as much as possible to improve resource utilization. Besides, overlapping technology of backup copies is employed. Compared with NOQAFT and DYFARS, QAFT shows obvious superiority to others with higher scheduling quality by simulation experiments.

关键词： Quality of service Program processors real time systems Fault tolerance Fault tolerant systems Scheduling algorithm

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Traffic and mobility data collection for real-time applications

Traffic and mobility data collection for real-time applicati...

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international conference on Intelligent Transportation

作者： J. Lopes J. Bento E. Huang C. Antoniou M. Ben-Akiva Instituto Superior Técnico Brisa Auto Estradas de Portugal Portugal MIT Intelligent Transportation System Laboratory Cambridge MA USA

Successful development of effective real-time traffic management and information systems requires high quality traffic information in real-time. this paper presents the state-of-the-art of traffic and general mobility sensory technology and a suite of methods for data pre-processing and cleaning for real-time applications. We propose a suite of methods and techniques to be applied from traffic data acquisition, preprocessing, transformation and integration until data advanced processing and transfer. Next, we detail some techniques for data preprocessing and integration, or fusion, phases. Even though the comprehensive use of historical traffic data and assignment models to support the most part of online services and operations, real-time data is extremely important to promote models' accuracy and, therefore, the reliability of information and outputs derived from data fusion and processing. Together with techniques and theoretical formulas we present a case study applied to the Portuguese Brisa's A5 motorway, a 25 km inter-urban highway between Lisbon and Cascais. Traffic on this motorway heading to Lisbon in the morning rush hours typically experiences high levels of congestion. Brisa, the motorway operator company, has equipped A5 with a variety of traffic sensors to be used in a real-time multi-purpose way, either for traffic management and control or for traveler information and third-part applications.

关键词： Vehicles Sensors real time systems Roads Traffic control Data preprocessing Telematics

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Towards Garbage Collection Mechanism for RTSJ-Oriented embedded Java Processor

Towards Garbage Collection Mechanism for RTSJ-Oriented Embed...

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international conference on Computer and Information Technology (CIT)

作者： Guang Hu Zhilei Chai Wenke Zhao Shiliang Tu Department of Computer Science Department of Computer Science and Engineering Fudan University Shanghai China Center of Intelligent and High Performance Computing School of Information Technology Jiangnan University Wuxi China Siemens Corporate Technology Beijing China Department of Computer Science and Engineering Fudan University Shanghai China

Currently, Java has been gradually applied in embedded real-time area with the improvement by the real-time Specification for Java (RTSJ). Accordingly, a hardware Java execution engine for embedded real-time applications, JPOR-32 (32-bit Java Processor Optimized for RTSJ), is designed. Taking JPOR-32 for an example, this paper presents the garbage collection mechanism for RTSJ-oriented embedded processor in detail. JPOR-32 provides effective architectural support for garbage collection. And the object reference format of JPOR-32 provides supports for objects tracing and heap scanning. the support for write barrier of real-time concurrent GC is also performed. Moreover, JPOR-32 provides optimized instruction level support for garbage collection. In addition, different garbage collection algorithms are compared on the base of the resource-constrained feature and the real-time requirement of the processor, and the hybrid garbage collectors are suggested.

关键词： Java real time systems Resource management Registers Memory management Loading Head

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Proceedings - 14th ieee international conference on embedded and real-time computing systems and applications, RTCSA 2008: Preface

Proceedings - 14th IEEE International Conference on Embedded...

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Proceedings - 14th ieee international conference on embedded and real-time computing systems and applications, RTCSA 2008 2008年 x页

作者： Shih, Chi-Sheng Fohler, Gehard Satoh, Ichiro

No abstract available

ISBN: (纸本)9780769533490

No abstract available

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