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Push-on-Demand: An enhancement to IEEE 802.11e EDCA for AP downlink access provisioning

Dongbei Daxue Xuebao/Journal of Northeastern University 2010年第SUPPL. 2期31卷 275-278+287页

作者： Dong, Yong-Qiang Xiang, Wu Wang, Yun School of Computer Science and Engineering Southeast University Nanjing 210096 China Key Laboratory of Computer Network and Information Integration Ministry of Education Southeast University Nanjing 210096 China Financial Bureau Information Center of Lishui Zhejiang Province Lishui 323000 China

In IEEE 802.11e EDCA wireless LANs, the capability of AP for channel access is equivalent to those of ordinary stations, which makes it hard to satisfy the throughput and delay requirements of AP downlink traffic under heavy load conditions. Taking the delay constraints of real-time traffic into consideration, an improved EDCA scheme was proposed to enhance AP downlink access provisioning. The essential mechanism is called Push-on-Demand operation which shall be trigged if there are too many frames accumulated in AP's transmission queues, or the queueing time of a real-time frame appears too long to satisfy the service requirements. While in Push state, AP can access channel directly to transmit frames, bypassing the contention window-based backoff procedure. To resolve the collisions between contending ACs within AP, interior collision scheduler is designed deliberately, and Push-Deferred state is defined further to protect wireless channel against greedy external traffic. Simulation results show that the proposed EDCA scheme enhances effectively the capability of AP for channel access, leading to improved downlink access provisioning in IEEE 802.11e wireless LANs.

关键词： Wireless local area networks (WLAN)

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Distance Estimation by Constructing The Virtual Ruler in Anisotropic Sensor networks

Distance Estimation by Constructing The Virtual Ruler in Ani...

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2010 Proceedings IEEE INFOCOM

作者： Yun Wang Kai Li Jie Wu School of Computer Science & Engineering Southeast University Key Lab of Computer Network and Information Integration MOE Nanjing China 210096 Department of Computer and Information Sciences Temple University Philadelphia PA 119122

ISBN: (纸本)9781424458363

Distance estimation is fundamental for many functionalities of wireless sensor networks and has been studied intensively in recent years. A critical challenge in distance estimation is handling anisotropic problems in sensor networks. Compared with isotropic networks, anisotropic networks are more intractable in that their properties vary according to the directions of measurement. Anisotropic properties result from various factors, such as geographic shapes, irregular radio patterns, node densities, and impacts from obstacles. In this paper, we study the problem of measuring irregularity of sensor networks and evaluating its impact on distance estimation. In particular, we establish a new metric to measure irregularity along a path in sensor networks, and identify turning nodes where a considered path is inflected. Furthermore, we develop an approach to construct a virtual ruler for distance estimation between any pair of sensor nodes. The construction of a virtual ruler is carried out according to distance measurements among beacon nodes. However, it does not require beacon nodes to be deployed uniformly throughout sensor networks. Compared with existing methods, our approach neither assumes global knowledge of boundary recognition nor relies on uniform distribution of beacon nodes. Therefore, this approach is robust and applicable in practical environments. Simulation results show that our approach outperforms some previous methods, such as DV-Distance and PDM.

关键词： Distance Estimation Wireless Sensor networks Virtual Ruler

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P2P-based application-layer multicast tree active update mechanism

P2P-based application-layer multicast tree active update mec...

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International Seminar on Future information Technology and Management Engineering, FITME

作者： Yang, Xianhe Shen, Jun Peng, Wei School of Computer Science and Engineering Southeast University Nanjing Jiangsu China Key Laboratory of Computer Network and Information Integration of Ministry of Education Southeast University Nanjing Jiangsu China

ISBN: (纸本)9781424490882

Currently most of the high-bandwidth internet applications use both P2P technology and application-layer multicast technology. Considering the loose coupling between the P2P technology and application-layer multicast technology in the existing applications, this paper proposes a new active update mechanism of P2P-based application-layer multicast tree from the view of the network architecture. This active update mechanism makes full use of the fault-tolerance and detection capabilities of P2P technology, sends feedback information of underlying network actively, and triggers the strategic management module of application-layer multicast These studies demonstrate that such active update mechanism can enhance the efficiency of the update of application-layer multicast tree and decrease the number of reconstruction of multicast tree to guarantee its stability by using redundant state information and alternative capacity of P2P technology. © 2010 IEEE.

关键词： network architecture

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D-TDMA: An Approach of Dynamic TDMA Scheduling for Target Tracking in Wireless Sensor networks

D-TDMA: An Approach of Dynamic TDMA Scheduling for Target Tr...

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IEEE/ACM Int'l Conference on & Int'l Conference on Cyber, Physical and Social Computing (CPSCom) Green Computing and Communications (GreenCom)

作者： Yun Wang Peizhong Shi Kai Li Zhikui Chen Department of Computer Science & Engineering Key Laboratory of Computer Network and Information Integration MOE South-East University Nanjing China School of software technology Dalian university of technology Dalian China

ISBN: (纸本)9781424497799

In the application of target tracking based on dynamic convey tree-based collaboration (DCTC) in wireless sensor networks, collisions and interferences among nodes pose a challenge for data aggregation. In this paper, we refine slot allocation to the nodes in dynamic convey tree and design an energy efficient MAC protocol called D-TDMA, which avoids collisions and interferences and allocates contiguous active slots to nodes as far as possible during data aggregation from leaf nodes to a root node. As a result, the energy consumption in switching from sleeping to active state is saved. Simulation results show that D-TDMA not only gets rid of the impact of collisions and interferences among nodes in dynamic convey tree, but also performs similar throughput to that of CSMA-like mechanism where nodes work without active/sleep scheduling strategy. Our protocol outperforms ESR in both energy efficiency and low delay.

关键词： Wireless sensor networks Target tracking Dynamic scheduling Interference Resource management Protocols Sensors

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SOA-based method for cooperative tasks distribution in large-scale optimization environments

SOA-based method for cooperative tasks distribution in large...

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International Conference on computer Supported Cooperative Work in Design

作者： Qiuxiang Cui Xia Zhu Yi Zhang Xiaoping Li Key Laboratory of Computer Network and Information Integration Ministry of Education South-East University Nanjing China School of Computer Science & Engineering Southeast University Nanjing P.R. China

In this paper, operators are encapsulated by services in algorithms for large-scale optimization problems and the services are deployed in distributed systems. Response time is an important factor for the performance of cooperative services. The message parse time is analyzed. Initial service accessing time is the main overhead for service calling. To decrease both the initial time and the response time, SBP (Service Buffering Pool based Scheduling Algorithm) is proposed by integrating a resource pool with a cache. Appropriate number of computing resources can be determined for large-scale optimization problems after analyzing the influence of the number of computing resources on algorithms. The proposed algorithm is compared with a centralized algorithm and a distributed algorithm without cache. Experimental results show that the proposed algorithm has a lower overhead than the other two algorithms.

关键词： Large-scale systems Optimization methods Web services Simple object access protocol Scheduling algorithm Delay Algorithm design and analysis Distributed computing Middleware Time factors

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A reputation-based trust model for P2P systems

A reputation-based trust model for P2P systems

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2009 International Conference on Computational Intelligence and Security, CIS 2009

作者： Wu, Peng Wu, Guoxin Key Laboratory of Computer Network and Information Integration Ministry of Education School of Computer Science and Engineering Southeast University Nanjing China

ISBN: (纸本)9780769539317

One of the fundamental challenges for Peer to Peer (P2P) systems is the ability to manage risks involved in interacting and collaborating with prior unknown and potentially malicious parties. Reputation-based trust management systems have proven to be essential to enforcing cooperative behavior in P2P networks. However, in many existing reputation-based trust models, the validity of peers' trust valuation is seriously affected by peers' malicious behaviors, such as strategic cheating, dishonest recommending and collusion. In this paper, we propose a novel reputationbased trust model for P2P systems. In our approach, the trustworthiness of peers consists of the experience-based and recommendation-based trust. To provide adequate reaction to peers' malicious behaviors, some factors are introduced to distinguish these experiences about peers' behaviors. Simulation shows that the proposed model has advantages in countering peers' malicious behaviors over the existing trust models. © 2009 IEEE.

关键词： Peer to peer networks

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Policy-driven autonomic network resource management for observation and detection data communication

Policy-driven autonomic network resource management for obse...

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2009 International Conference on High Performance Computing, networking and Communication Systems, HPCNCS 2009

作者： Feng, Jing Ma, Weijun Liu, Dawei Yu, Xiaoxing Institute of Meteorology PLA University of Science and Technology Nanjing 211101 China Key Laboratory of Computer Network and Information Integration Ministry of Education Southeast University Nanjing 210096 China School of Information Science and Engineering Southeast University Nanjing 210096 China

ISBN: (纸本)9781615676606

The increase of the business and management complexity requires more adaptive and higher selfmanaged equipments, application processes and management systems, which promotes the development of autonomic computing and communication networks. The meteorological and hydrological business system (MHBS) is a typical composite functional system, which includes data collecting, transporting, convergence and clean up, distributing and publishing, pre-processing, storage, and weather forecasting. In order to realize self-management of MHBS, autonomic concept is introduced and autonomic network management architecture with associated model is proposed firstly. According to the measured data from observation and / or detection devices, the system may perceive the work situations of these devices by means of prediction models. Driven by a set of system management polices, some well-defined events can be processed, which enable generating configuration and adjustment suggestions automatically. The instances of policy-driven data communication management with multiple channels are given literally to show the model's mechanisms.

关键词： Weather forecasting

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QoS and Preference Based Web Service Evaluation Approach

QoS and Preference Based Web Service Evaluation Approach

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International Conference on Grid and Cooperative Computing (GCC)

作者： Jiuxin Cao Jingyu Huang Guojin Wang Jun Gu School of Computer Science and Engineering Jiangsu Provincial Key Laboratory of Network and Information Security Key Laboratory of Computer Network and Information Integration Ministry of Education South-East University Nanjing China

With the advance of Web services and applications, quality of service (QoS) has becoming a key issue in Web service selection. Current discovery model and standards such as UDDI, WSDL do not give much support to QoS description and evaluation. Meanwhile, many researches only focus on QoS model and computation, without taking user individual preference into consideration. How to dynamically evaluate candidate Web services based on user preference is an important problem to be solved. This paper proposes a QoS and user preference based evaluation model called Q-WSEM(QoS-based Web service evaluation model) that extends the existing model by adding Web service evaluation center, and establishes a three-layer framework to achieve Web service evaluation based on QoS and user preference. In the third layer, information entropy method of multiple-attribute decision making theory is adopted to facilitate QoS assessment, and preference model is also introduced to provide interface for user to modify preference-based objective weight. Moreover, we have developed and implemented a Q-WSEM prototype, and measured the validity under different preferences. Experiment results demonstrate the effectiveness of this approach.

关键词： Web services Quality of service computer networks Laboratories information entropy Decision making Web and internet services Grid computing computer science information security

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A SOA Based Framework of Service Ability Description and Selection Methods for Application integration in Manufacturing Domain

A SOA Based Framework of Service Ability Description and Sel...

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International Conference on Interoperability for Enterprise Software and Applications China, IESA

作者： Weihua Huang Xiaoping Li School of Computer Science & Engineering Key Laboratory of Computer Network and Information Integration Ministry of Education South-East University Nanjing China

In this paper, an SOA based framework for service ability description and selection methods is proposed for the application integration in manufacturing domain. A uniform and standard schema is introduced to accurately describe both user requirements and service abilities. Services are organized and classified by an index tree, by which the service ability matching procedure which is the key of service selection can be simplified. An effective matching algorithm is presented along with the matching degree definition and calculation. The entire framework is implemented.

关键词： Service oriented architecture Application software Pulp manufacturing computer aided manufacturing computer integrated manufacturing Classification tree analysis computer science Laboratories computer networks computer science education

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A Novel Clustering Algorithm in Wireless Sensor networks

A Novel Clustering Algorithm in Wireless Sensor Networks

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International Conference on Industrial and information Systems, IIS

作者： Jiangpeng Dai Shu Liu Key Laboratory of Computer Network and Information Integration Ministry of Education School of Computer Science & Engineering South-East University Nanjing China

ISBN: (纸本)9781424439362

The demands of energy-efficient, distributed and scalable features are critical factors for designing topology control and routing management scheme in wireless sensor networks. To meet these demands, clustering is a good method in sensor networks topology control and routing. But by analyzing former clustering algorithms, it is found that there are deficiencies and limitations because of the usage of random method in cluster head election. In this paper, clustering mechanism is modeled and analyzed theoretically, and then turned to approximate optimization problem. A novel heuristic information based clustering algorithm is proposed to solve the above problem. The performance of this novel algorithm is analyzed and validated by simulation experiments. The results of experiments indicate that the algorithm can conduct clustering in network well and obtain excellent network performance, such as improved robustness, lower global energy cost and longer network lifetime. In particular, the performance is still stable while increasing the nodes scale.

关键词： Clustering algorithms Wireless sensor networks network topology Routing Algorithm design and analysis Energy efficiency Energy management Nominations and elections Performance analysis Analytical models

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