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IEEE International Conference on Wireless and Mobile computing, Networking And Communications (WiMob)

作者： J. Naoum-Sawaya B. Ghaddar S. Khawam H. Safa H. Artail Z. Dawy Department of Electrical and Computer Engineering American University of Beirut Beirut Lebanon Mobile Computing and Networking Research Laboratory (LARIM) Ecole Polytechnique de Montreal Montreal Canada Department of Computer Science American University of Beirut Beirut Lebanon

the IEEE 802.11e standard has been introduced recently for providing quality of service (QoS) capabilities in the emerging wireless local area networks. This standard introduces a contention window based enhanced distributed channel access (EDCA) technique that provides a prioritized traffic to guarantee the minimum bandwidth needed for time critical applications. However, the EDCA technique resets statically the contention window of the mobile station after each successful transmission. This static behavior does not adapt to the network state hence reduces the network usage and results in bad performance and poor link utilization whenever the demand for link utilization increases. This paper proposes a new adaptive differentiation technique for IEEE 802.11e wireless local area networks that takes into account the network state before resetting the contention window. The performance of the proposed technique is evaluated compared to the original differentiation techniques of the IEEE 802.11a and IEEE 802.11e standards. Preliminary results show that the proposed adaptive technique enhances the channel utilization and increases throughput.

关键词： Wireless LAN Quality of service Bandwidth Intelligent networks Telecommunication traffic Throughput Helium Local area networks IP networks Delay

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I/O profiling for distributed IP storage systems

I/O profiling for distributed IP storage systems

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International Conference on Embedded Software and Systems

作者： Jizhong Han Dan Zhou Xubin He Jinzhu Gao Institute of Computing Technology Chinese Academy and Sciences Beijing China Department of Electrical & Computer Engineering Tennessee Technological University Cookeville TN USA Computer Science & Mathematics Division Oak Ridge National Laboratory Oak Ridge TN USA

The popularity of Web services demands data storage over the network. iSCSI is a newly emerging protocol with the goal of deploying storage over the mature TCP/IP in an economic and convenient way. In a typical Web service using iSCSI storage systems, I/O requests issued by Web users can be satisfied by different parties, such as client cache, proxy cache, Web server cache, iSCSI target cache, and disks, along the I/O path from Web clients to iSCSI storage. Understanding the characteristics of I/O traffic under such environment is increasingly important as the networked storage prevails. This paper profiles I/O for Web services using iSCSI storage systems and identifies how these I/O requests are distributed and satisfied. Both simulation and benchmarking results show that the I/O profiling is helpful to identify I/O performance bottleneck of Web services and helps to improve iSCSI performance.

关键词： Web services IP networks TCPIP Cache storage Memory Protocols Web server Storage area networks Web and internet services Telecommunication traffic

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Journal of Information science and engineering: Editorial notice

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Journal of Information science and engineering 2005年第5期21卷 i-ii页

作者： Lee, Der-Tsai Amato, Nancy M. Chang, Shih-Fu Chen, Homer H. Chen, Tsuhan Hsu, Tsan-Sheng Hwang, Jenq-Neng Kuo, Sy-Yen Kuo, Tei-Wei Li, Chung-Sheng Tokuyama, Takeshi Wing, Jeannette Wu, Tzong-Chen Yen, John Computer Science at Texas A and M University United States Parasol Laboratory United States IEEE Transactions on Parallel and Distributed Systems Computing Research Association's Committee on the Status of Women in Computing Research CRA-W's Distributed Mentor Program United States Department of Electrical Engineering Columbia University United States Lab. United States College of Electrical Engineering and Computer Science National Taiwan University Taiwan IEEE Transactions on Circuits and Systems for Video Technology IEEE Department of Electrical and Computer Engineering Carnegie Mellon University Pittsburgh PA United States ACM ACM SIGACT IEEE Computer Society IICM Austria Research and Development of the Department Multimedia Signal Processing Technical Committee IEEE Signal Processing Society United States IEEE Transactions on Circuits and systems for Video Technology College of Electrical Engineering and Computer Science National Taiwan Ocean University Keelung Taiwan Department of Electrical Engineering National Taiwan University Taiwan Department of Computer Science and Information Engineering National Taiwan University Taipei Taiwan IEEE Technical Committee on Real-Time Systems Computer Science Division IBM T.J. Watson Research Center United States IBM Research Division Graduate School of Information Sciences Tohoku University Japan ACM IPSJ Mathematical Society of Japan Japan Department of Computer Science Computer Science Department Carnegie Mellon University United States National Academies of Science's Computer Science and Telecommunications Board United States Microsoft's Trustworthy Academic Advisory Board Intel Research Pittsburgh's Advisory Board United States Dartmouth's Institute for Security Technology Studies Advisory Committee Canada Sloan Research Fellowships Program Committee United States ACM Taiwan China Information Sciences and Technology Pennsylvania State University United States Laboratory for Intelligent Agents Penn State's School of Info

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real time head tracking via camera saccade and shape-fitting

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2nd International Conference on Image Analysis and Recognition, ICIAR 2005

作者： Zhang, Jason Z. Lu, Ye Wu, Q.M. Jonathan Micro-technology and Sensing Group Institute for Fuel Cell Innovation National Research Council of Canada Vancouver BC V6T 1W5 Canada Vision and Media Laboratory School of Computing Science Simon Fraser University Burnaby BC V5A 1S6 Canada Department of Electrical and Computer Engineering University of Windsor Ont. N9B 3P4 Canada

ISBN: (纸本)3540290699

This paper presents a system that tracks human heads in real-time under unconstrained environments where target occlusion, varying illumination, and cluttered backgrounds exist. Tracking is formulated as an active visual servo problem based on the integration of a saccade and a smooth pursuit processes. The head is modelled as an ellipse computed from the color clusters of candidate targets using a robust least square ellipse fitting algorithm. The Farnsworth Perceptually Uniform Color Model is employed to represent the color information of the visual objects. Kalman filtering is applied to the head ellipse to track the evolution of the position, size, and orientation of the target such that the occlusion of objects with similar color and shape as those of the target are effectively accommodated. Experiments with tracking scenarios demonstrate the effectiveness of the system. © Springer-Verlag Berlin Heidelberg 2005.

关键词： Tracking (position)

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LiSP: A Lightweight Security Protocol for Wireless Sensor Networks

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ACM Transactions on Embedded computing Systems 2004年第3期3卷 634-660页

作者： Park, Taejoon Shin, Kang G. Real-Time Computing Laboratory (RTCL) Department of Electrical Engineering and Computer Science The University of Michigan Ann Arbor MI 48109-2122 United States

Small low-cost sensor devices with limited resources are being used widely to build a self-organizing wireless network for various applications, such as situation monitoring and asset surveillance. Making such a sensor network secure is crucial to their intended applications, yet challenging due to the severe resource constraints in each sensor device. We present a lightweight security protocol (LiSP) that makes a tradeoff between security and resource consumption via efficient rekeying. The heart of the protocol is the novel rekeying mechanism that offers (1) efficient key broadcast without requiring retransmission/ACKs, (2) authentication for each key-disclosure without incurring additional overhead, (3) the ability of detecting/recovering lost keys, (4) seamless key refreshment without disrupting ongoing data encryption/decryption, and (5) robustness to inter-node clock skews. Furthermore, these benefits are preserved in conventional contention-based medium access control protocols that do not support reliable broadcast. Our performance evaluation shows that LiSP reduces resource consumption significantly, while requiring only three hash computations, on average, and a storage space for eight keys. © 2004, ACM. All rights reserved.

关键词： Authentication Design key management lightweight security Security sensor networks

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Integrated modeling and analysis of automotive embedded control systems with real-time scheduling

Integrated modeling and analysis of automotive embedded cont...

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2004 SAE World Congress

作者： Gu, Zonghua Wang, Shige Kim, Jeong Chan Shin, Kang G. Real-Time Computing Laboratory Electrical Engineering and Computer Science Dept. University of Michigan Ann Arbor MI 48109 United States

ISBN: (纸本)0768013194

As the complexity of automotive embedded software grows, it is desirable to bring as much automation into the development process as possible, as evidenced by efficient code generators from modeling tools such as Simulink. However, the current development process does not pay enough attention to non-functional issues such as real-time requirements. Modeling tools such as Simulink do not allow representation of the target platform, so it is not possible to analyze real-time behavior in the early design stage. The typical approach is to download the executable to the target micro-controller and measure to see if there are any missed deadlines. We describe a tool that can be used to model system-level software and hardware architectures and analyze system timing behavior at early design stages, and assess the impact of the target platform on control system performance. Copyright © 2004 SAE International.

关键词： Simulink

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On soft real-time guarantees on ethernet

On soft real-time guarantees on ethernet

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9th International Conference on real-time and Embedded computing Systems and Applications, RTCSA 2003

作者： Cho, Min-gyu Shin, Kang G. Real-Time Computing Laboratory Department of Electrical Engineering and Computer Science The University of Michigan Ann ArborMI48109-2122 United States

ISBN: (纸本)9783540246862

The medium access protocol of Ethernet, CSMA/CD, has an inherent limitation in providing real-time guarantees. Since Ethernet is the most commonly used local area network (LAN) technology due to its low cost, high bandwidth and robustness, it is very important to overcome this problem so that Ethernet can be used as a network for soft real-time applications like multimedia. An adaptive traffic smoother (ATS) was proposed as a kernel-level software solution that provides soft real-time guarantees on Ethernet. This paper addresses the reconfigurability, scalability and portability of ATS. First, a mechanism to read and adjust several user-specific parameters of ATS is discussed, and metrics or parameters to indicate the achievement of the user-required Quality-of-Service (QoS) are developed since these parameters are indirectly related to the user-specific QoS. Our experimental evaluation validates the feasibility of enhancing the reconfigurability and portability of ATS. Second, ATS is extended to a switched Ethernet which is commonly used for scalability. Our solution employs an ATS for each port of the switch for real-time packet delivery guarantees. Finally, a prototype of the user-level ATS is implemented and evaluated to enhance the portability of ATS. The performance of this user-level ATS is shown to be comparable to that of the kernel-level implementation, while enhancing both the reconfigurability and portability of real-time Ethernet solutions. © Springer-Verlag Berlin Heidelberg 2004.

关键词： Ethernet

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Component allocation with multiple resource constraints for large embedded real-time software

Component allocation with multiple resource constraints for ...

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Proceedings - RTAS 2004 10th IEEE real-time and Embedded Technology and Applications Symposium

作者： Wang, Shige Merrick, Jeffrey R. Shin, Kong G. Real-Time Computing Laboratory Department of Electrical Engineering University of Michigan Ann Arbor MI 48109-2122

ISBN: (纸本)0769521487

Allocating software components while meeting multiple platform resource constraints is crucial for model-based design of large embedded real-time software and automatic design model transformation. In this paper, we propose a new method for component allocation using an informed branch-and-bound and forward checking mechanism subject to a combination of resource constraints. We have implemented this method in the Automatic Integration of Reusable Embedded Software (AIRES) toolkit - which has been developed under the DARPA MoBIES Program - and applied it to an automotive electronic throttle control (ETC) system. Our evaluation based on randomly-generated design models has shown that the proposed method scales well for large and complex embedded real-time software.

关键词： real time systems

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Multi-view modeling and analysis of embedded real-time software with meta-modeling and model transformation

Multi-view modeling and analysis of embedded real-time softw...

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Proceedings - Eighth IEEE International Symposium on High Assurance Systems engineering

作者： Gu, Zonghua Wang, Shige Kodase, Sharath Shin, Kang G. Real-Time Computing Laboratory Department of Electrical Engineering University of Michigan Ann Arbor MI 48109-2122 United States

We present an end-to-end tool-chain for model-based design and analysis of component-based embedded real-time software, with Avionics Mission computing as an application domain. The tool-chain covers the entire system development life-cycle including modeling, analysis, code generation, and runtime instrumentation. Emphasis is placed on integration of tools developed by multiple institutions via standardized interface format definitions in XML. All aspects of an embedded real-time system are captured in domain-specific models, including software components and architecture, timing and resource constraints, processes and threads, execution platforms, etc. Configuration code generation allows automated building of the application executable. Instrumentation of the application running on a target platform is used to collect runtime statistics that are fedback into the models. Analysis tools perform various static analyses based on the models, including system-level dependency analysis, execution-rate assignment to component ports, real-time and schedulability analysis, and automated allocation of components to processors. By capturing all relevant information explicitly in models at the design level, and performing analysis that provides insight into non-functional aspects of the system, we can raise the level of abstraction for the designer, and facilitate rapid system prototyping.

关键词： Embedded systems

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Bonding plus: real-time message channel in linux ethernet environment using regular switching hub

Bonding plus: Real-time message channel in linux ethernet en...

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9th International Conference on real-time and Embedded computing Systems and Applications, RTCSA 2003

作者： Lin, Hsin-hung Hsueh, Chih-wen Huang, Guo-Chiuan Real-Time Systems Laboratory Department of Computer Science and Information Engineering National Chung Cheng University Chiayi621 Taiwan

ISBN: (纸本)9783540246862

Bandwidth management is very important to quality of service of network applications. Communications and data transmissions between hosts in a LAN environment may be large in many systems, such as clustering systems and parallel systems. If the network bandwidth is not enough, real-time packets may be delayed and miss their timing constraints. There are many technologies developed to increase host bandwidth in a LAN environment, but most of them need switching hubs with special support such as IEEE Link Aggregation Standard and are very expensive. In this paper, we propose a real-time message channel, BondingPlus, in Linux Ethernet environment which can make use of multiple Ethernet adapters simultaneously between hosts connected with regular switching hubs. When receiving packets from upper network layer, BondingPlus schedules packets in data link layer. real-time packets can be dispatched into a higher-priority queue so that the packets can be transmitted through the physical Ethernet interface right away. Furthermore, real-time applications can transmit real-time packets via one or several dedicated network adapters which create real-time message channels between hosts and thus reduce transmission delay and jitter dramatically, especially suitable for applications that have high bandwidth and real-time requirements. This approach is implemented in two Linux kernel modules and is backward compatible, flexible and transparent to users. BondingPlus pseudo Ethernet device driver module receives packets from upper network layer and dispatches the packets to multiple physical network adapters with a single IP address. ARP+ protocol module is responsible for maintaining a table of the mapping between an IP address and its corresponding MAC addresses of multiple physical network adapters. © Springer-Verlag Berlin Heidelberg 2004.

关键词： Ethernet

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