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29th ieee international conference on Distributed computing systems

作者： Mangharam, Rahul Pajic, Miroslav Univ Penn Dept Elect & Syst Engn Philadelphia PA 19104 USA

ISBN: (纸本)9781424444465

embedded wireless networks have largely focused on open-loop sensing and monitoring. To address actuation in closed-loop wireless control systems there is a strong need to re-think the communication architectures and protocols for reliability, coordination and control. As the links, nodes and topology of wireless systems are inherently unreliable, such time-critical and safety-critical applications require programming abstractions where the tasks are assigned to the sensors, actuators and controllers as a single component rather than statically mapping a set of tasks to a specific physical node at design time. To this end, we introduce the embedded Virtual Machine (EVM), a powerful and flexible programming abstraction where virtual components and their properties are maintained across node boundaries. In the context of process and discrete control, an EVM is the distributed runtime system that dynamically selects primary-backup sets of controllers to guarantee QoS given spatial and temporal constraints of the underlying wireless network. the EVM architecture defines explicit mechanisms for control, data and fault communication within the virtual component. EVM-based algorithms introduce new capabilities such as predictable outcomes and provably minimal graceful degradation during sensor/actuator failure, adaptation to mode changes and runtime optimization of resource consumption. through the design of a natural gas process plant hardware-in-loop simulation we aim to demonstrate the preliminary capabilities of EVM-based wireless networks.

关键词： real-time systems embedded systems wireless sensor networks virtual machines

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SDSPM-based User Interest Prediction in Collaborative Graphics Design systems under Ubiquitous Environment

SDSPM-based User Interest Prediction in Collaborative Graphi...

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13th international conference on Computer Supported Cooperative Work in Design

作者： Jiang, Bo Zhou, Jian Bu, Jiajun Zhejiang Gongshang Univ Coll Comp & Informat Engn Hangzhou Zhejiang Peoples R China Zhejiang Univ Coll Comp Sci Zhengzhou Peoples R China

ISBN: (纸本)9781424435340

Rapid advances in the enabling technologies for mobile and ubiquitous computing help portable devices to join collaborative graphics design conveniently. the limitation of display size and computational power of these embedded devices makes it hard for mobile users to browse large pattern that renewed in real time efficiently. We present a novel user interest region prediction algorithm and related system that use state duration based segmental probability model (SDSPM) to forecast user's intention in the near future. Related experiment was carried out to test the effectiveness of the algorithm. Based on the prediction, only sub-patterns that might be interested to user are issued to the embedded sites. the proposed user interest prediction system is effective and the feasibility of the collaborative graphics design system in ubiquitous environment is enhanced.

关键词： SDSPM User Interest Collaborative Graphics Design System Ubiquitous Environment

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Managing imprecise worst case execution times on DVFS platforms

Managing imprecise worst case execution times on DVFS platfo...

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15th ieee international conference on embedded and real-time computing systems and applications, RTCSA 2009

作者： Berten, Vandy Chang, Chi-Ju Kuo, Tei-Wei Fonds National de la Recherche Scientifique Université Libre de Bruxelles Brussels Belgium CSIE National Taiwan University Taipei Taiwan

ISBN: (纸本)9780769537870

Although energy-efficient real-time task scheduling has attracted a lot of attention in the past decade, most existing results assumed deterministic execution lengths for tasks, or probabilistic lengths with a stable distribution. Such an assumption results in significant difficulty in their application to real problems. In this work, we relax this hypothesis by assuming that the worst case execution number of cycles (WCEC) might be imprecisely known. We present several methods to react to such a situation. We provide simulation results attesting that with a small effort, we can provide very good results, allowing to keep a low deadline miss rate as well as an energy consumption similar to clairvoyant algorithms. the main contribution of this work is to improve the robustness of low-power scheduling algorithms on DVFS (Dynamic Voltage and Frequency Scaling) frame-based platforms. © 2009 ieee.

关键词： real time systems

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An Improved Algorithm to Smooth Delay Jitter in Cyber-Physical systems

An Improved Algorithm to Smooth Delay Jitter in Cyber-Physic...

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international conference on Scalable computing and Communications/8th international conference on embedded computing

作者： Al-Omari, Huthaifa Wolff, Francis Papachristou, Christos McIntyre, David Case Western Reserve Univ Dept Elect Engn & Comp Sci Cleveland OH 44106 USA Cleveland State Univ Dept Comp & Informat Sci Cleveland OH 44115 USA

ISBN: (纸本)9781424453320

Delay jitter is a critical factor that must be considered in networked real-time applications that require accurate prediction of packet delivery times. Delay jitter can be smoothed by holding packets in a play-back buffer for a certain time called a play-back delay. In this paper, we propose a scheme to enhance the prediction of the play-back delay in Networked Control systems (NCSs) with no need for clock synchronization. Our newly proposed scheme differs from previous schemes by using the one way delay variation. We have studied the behavior of one way delay variation by conducting extensive measurements between 50 strategically located wired and wireless connected hosts. the advantage of our scheme is that it significantly improves handling of sudden delay spikes, provides a closer approximation to the round trip time (RTT), and exhibits less frequent outliers.

关键词： Networked control systems

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Implementing OpenGL ES on OpenGL

Implementing OpenGL ES on OpenGL

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2009 ieee 13th international Symposium on Consumer Electronics, ISCE 2009

作者： Hwanyong, Lee Nakhoon, Baek Huone Inc. Bokhyun-dong 573-13 Daegu 702-020 Korea Republic of School of EECS Kyungpook National University Korea Republic of School of EECS Kyungpook National University Daegu 702-701 Korea Republic of Mobile Graphics Inc. Daegu Korea Republic of

ISBN: (纸本)9781424429769

We present an OpenGL ES implementation which utilizes the existing OpenGL library, aiming to support various embedded systems in current consumer markets. Nowadays OpenGL ES becomes an improved version of OpenGL for embedded systems through introducing new features including the fixed-point numeric type. We optimized arithmetic operations on its specific data types such as fixed-point numbers, and achieved totally new optimized implementations of newly introduced features. Efficient ways of parameter conversions between our OpenGL ES implementation and underlying OpenGL are also accomplished even with strictly obeying the standard specifications. Our final implementation result of OpenGL ES 1.1 library completely provides more than 200 API functions in the standard specification and satisfies all the conformance tests. From the efficiency point of view, we compared execution speeds of real world applications to existing commercial implementations to finally show at most 33.147 times speed-ups, which is fastest among the same category implementations. ©2009 ieee.

关键词： embedded systems

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A portable and efficient User Dispatching Mechanism for multicore systems

A portable and efficient User Dispatching Mechanism for mult...

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15th ieee international conference on embedded and real-time computing systems and applications, RTCSA 2009

作者： Tu, Tang-Hsun Hsueh, Chih-Wen Chang, Rong-Guey Embedded System and Wireless Network Laboratory Graduate Institute of Networking and Multimedia National Taiwan University Taipei 106 Taiwan System Software Laboratory Graduate Institute of Computer Science and Information Engineering National Chung Cheng University Chia-Yi 621 Taiwan

ISBN: (纸本)9780769537870

In multicore environment, using multiple threads is a common useful approach to improve application performance. Nevertheless, even in many simple applications, the performance might degrade when the number of threads increases. Users usually impute this phenomenon to the overhead of creation or termination of threads. However, in our observation, the more significant effect is the dispatching of threads. We discuss the problems on using threads, and present a novel User Dispatching Mechanism (UDispatch) that provides controllability in user space to improve application performance. Since user threads cannot directly control system resources, a virtual device is adopted between user space and operating system for portability and efficiency instead of adding new system calls through kernel modification. We also experiment UDispatch through multi-threading multimedia applications. the results show that a skip-line application speeds up to 111.3% and 111.6% on a 4-core machine and an 8-core machine, respectively, and an optimized H.264/AVC decoder speeds up to 18.4% on a 4-core machine. © 2009 ieee.

关键词： Computer architecture

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A conflict resolution methodology for collective ubiquitous context-aware applications

A conflict resolution methodology for collective ubiquitous ...

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2009 13th international conference on Computer Supported Cooperative Work in Design, CSCWD 2009

作者： Silva, thais R.M.Braga Loureiro, Antonio A.F. Ruiz, Linnyer Beatrys Computer Science Department Federal University of Minas Gerais Belo Horizonte Minas Gerais Brazil State University of Maringa Department of Informatics Maringa Parana Brazil

ISBN: (纸本)9781424435357

the context-aware computing is a research field that defines systems capable of adapting their behavior according to any relevant information about entities (e. g. , people, places and objects) of interest. the ubiquitous computing is closely related to the use of contexts, since it aims to provide personalized, transparent and on-demand services. Ubiquitous systems are frequently shared among multiple users, once they are designed to be embedded into everyday objects and environments such as houses, cars and offices. In scenarios where more than one user shares the same ubiquitous context-aware application, conflicts may occur during adaptation actions due to individual profiles divergences and/or environment resources incompatibility. In such situations it is interesting to use computer supportedcollaborative work techniques in order to detect and solve those conflicts, considering what is better for the group but also being fair enough with each individual demand, whenever possible. this work presents theimportant concepts on the collective ubiquitous context-aware applications field. Furthermore, it proposes a new methodology for conflicts detection and resolution that considers the trade-off between quality of services and resources consumption. © 2009 ieee.

关键词： Ubiquitous computing

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Presentation title: Cryptography in embedded environments

Presentation title: Cryptography in embedded environments

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2009 ieee 13th international Symposium on Consumer Electronics, ISCE 2009

作者： Matsui, Mitsuru Information Technology R and D Center Mitsubishi Electric Corporation Japan

ISBN: (纸本)9781424429769

this talk explores cryptographic algorithms and protocols in embedded computing environments. Cryptography is an essential technology for protecting privacy and secret information, and is now widely used in portable devices such as mobile phones and smart cards. How to design small and low power crypto algorithms is one of the central topics in cryptography, and in addition how to protect crypto devices from cryptanalytic attacks is another big challenge, which attracts many cryptographers from both theoretical and practical points of view. In this presentation, we begin with briefly introducing history of modern cryptography and cryptographic algorithms, and talk about software implementation techniques of cryptographic primitives for embedded environments. We then discuss recent advances of cryptanalysis methods against crypto devices called "side-channel attacks," which can extract secret information without giving any damage to the devices and hence often lead to serious threats to real-world crypto applications. the presentation will also include how to protect embedded systems from these powerful cryptanalytic attacks.

关键词： Smart cards

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Improving Quality-of-Service in Wireless Sensor Networks by Mitigating "Hidden-Node Collisions"

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ieee TRANSACTIONS ON INDUSTRIAL INFORMATICS 2009年第3期5卷 299-313页

作者： Koubaa, Anis Severino, Ricardo Alves, Mario Tovar, Eduardo Al Imam Muhammad Ibn Saud Univ Dept Comp Sci Riyadh 11681 Saudi Arabia Polytech Inst Porto ISEP IPP CISTER Res Unit P-431 Oporto Portugal

Wireless sensor networks (WSNs) emerge as underlying infrastructures for new classes of large-scale networked embedded systems. However, WSNs system designers must fulfill the quality-of-service (QoS) requirements imposed by the applications (and users). Very harsh and dynamic physical environments and extremely limited energy/computing/ memory/communication node resources are major obstacles for satisfying QoS metrics such as reliability, timeliness, and system lifetime. the limited communication range of WSN nodes, link asymmetry, and the characteristics of the physical environment lead to a major source of QoS degradation in WSNs-the "hidden node problem." In wireless contention-based medium access control (MAC) protocols, when two nodes that are not visible to each other transmit to a third node that is visible to the former, there will be a collision-called hidden-node or blind collision. this problem greatly impacts network throughput, energy-efficiency and message transfer delays, and the problem dramatically increases with the number of nodes. this paper proposes H-NAMe, a very simple yet extremely efficient hidden-node avoidance mechanism for WSNs. H-NAMe relies on a grouping strategy that splits each cluster of a WSN into disjoint groups of non-hidden nodes that scales to multiple clusters via a cluster grouping strategy that guarantees no interference between overlapping clusters. Importantly, H-NAMe is instantiated in ieee 802.15.4/ZigBee, which currently are the most widespread communication technologies for WSNs, with only minor add-ons and ensuring backward compatibility with their protocols standards. H-NAMe was implemented and exhaustively tested using an experimental test-bed based on "off-the-shelf" technology, showing that it increases network throughput and transmission success probability up to twice the values obtained without H-NAMe. H-NAMe effectiveness was also demonstrated in a target tracking application with mobile robots over a WSN depl

关键词： Energy-efficiency hidden-node problem networked embedded systems quality-of-service (QoS) timing performance wireless sensor networks (WSNs)

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Proceedings of the 2009 13th international conference on Computer Supported Cooperative Work in Design, CSCWD 2009

Proceedings of the 2009 13th International Conference on Com...

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2009 13th international conference on Computer Supported Cooperative Work in Design, CSCWD 2009

ISBN: (纸本)9781424435357

the proceedings contain 125 papers. the topics discussed include: many computers, many people, and everything in between: supporting shared computing;multiagent systems and semantic services for very large-scale participatory design;management strategy for distributed data in collaborative design;an ontological conceptualization approach for awareness in domain-independent design groupware;a role hierarchical group awareness model and its time possibility analysis based fuzzy time;model for planning problem of diaphragm caustic soda and its approach based on particle swarm optimization algorithm;leveraging single-user AutoCAD for collaboration by transparent adaptation;a self-embedded watermarking scheme based on relationship function of corresponding inter-blocks DCT coefficient;user-centered design and evaluation of support management system;and collaborative ethnography: an approach to the elicitation of cognitive requirements of teams.

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