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Networking and Communications, 2008. WIMOB '08. IEEE International Conference on Wireless and Mobile Computing,

Date 12-14 Oct. 2008

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Displaying Results 1 - 25 of 137
  • [Front cover]

    Page(s): C1
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  • [Title page i]

    Page(s): i
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  • [Title page iii]

    Page(s): iii
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  • [Copyright notice]

    Page(s): iv
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  • Table of contents

    Page(s): v - xiv
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  • Message from the General Chair

    Page(s): xv - xvi
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  • Message from the Technical Program Committee Co-chairs

    Page(s): xvii
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  • Message from the Workshops Co-chairs

    Page(s): xviii
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  • Message from the HWN-RMQ Workshop Organizing Technical Co-chairs

    Page(s): xix
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  • Message from the SAUCE Workshop Organizing Technical Co-chairs

    Page(s): xx
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  • Message from the SecPri Workshop Organizing Technical Co-chairs

    Page(s): xxi
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  • Message from the STWiMob Workshop Organizing Technical Co-chairs

    Page(s): xxii
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  • Organizing Committees

    Page(s): xxiii
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  • Program Committee

    Page(s): xxiv - xxvii
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  • Spectrum Management in Cognitive Radio Networks

    Page(s): xxviii
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  • Inter-vehicles Communication: A New Frontier of Ad Hoc Networking

    Page(s): xxix
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  • Rate Allocation with Lifetime Maximization and Fairness for Data Aggregation in Sensor Networks

    Page(s): 1 - 6
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (263 KB) |  | HTML iconHTML  

    We consider the rate allocation problem for data aggregation in wireless sensor networks with two objectives: 1) maximizing the lifetime of a local aggregation cluster and 2) achieving fairness among all data sources. The two objectives are generally correlated with each other and usually they cannot be maximized simultaneously. We adopt a lexicographic method to solve this multi-objective programming problem. First, we recursively induce the maximum lifetime for the local aggregation cluster. Under the given maximum lifetime, we then formulate the problem of maximizing fairness as a convex optimization problem, and derive the optimal rate allocation strategy. We also present low-complexity algorithms that a local aggregation cluster can use to determine the optimal rate allocation. Our simulation results validate our analytical results and illustrate the effectiveness of the approach. View full abstract»

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  • Adaptive Data-Gathering Protocols with Mobile Collectors for Vehicular Ad Hoc and Sensor Networks

    Page(s): 7 - 12
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (309 KB) |  | HTML iconHTML  

    Energy efficiency and low message delay are the basic QoS requirements for data collection in vehicular ad-hoc and sensor networks. In order to achieve these requirements, many solutions have been developed by attaching collectors/sinks to vehicle or aircraft and moving them either randomly or along a predefined route. This paper presents an adaptive data gathering protocol (ADG) that employs multiple mobile collectors (instead of sinks) to help an existing wireless sensor network achieve such requirements. In the proposed ADG protocol, a virtual elastic-force model is used to help mobile collectors adjust their moving speed and direction while adapting to changes within the network. Because of the irregularity of the information generation rate as well as the cost of mobile collectors, the number of collectors can not be predefined. Mobile collectors are sent out by sink if the information in the network is beyond the capabilities of existing mobile collectors, and are called back when they become redundant. In this paper we discuss our ADG protocol, highlight how its performance can be enhanced using both multi-hop OCOPS and LEACH protocols. We report on the performance evaluation of ADG protocol using an extensive set of simulation experiments. Our simulation results show that the proposed ADG algorithm can be a flexible means of meeting the constraints and different requirements of monitoring applications. View full abstract»

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  • Low-Power 2.4 GHz Wake-Up Radio for Wireless Sensor Networks

    Page(s): 13 - 18
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (230 KB) |  | HTML iconHTML  

    Power consumption is a critical issue in many wireless sensor network scenarios where network life expectancy is measured in months or years. Communication protocols typically rely on duty-cycle mechanisms to reduce the power usage at the cost of decreased network responsiveness and increased communication latency. A low-power radio-triggered device can be used to continuously monitor the channel and activate the node for incoming communications, allowing purely asynchronous operations. To be effective, the power consumption of this wake-up receiver must be on the order of tens of microwatts since this device is always active. This paper presents the ongoing efforts to design such a low-power receiver. Initial results indicate an average power consumption below 20 uW. View full abstract»

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  • Directional Sensor Placement with Optimal Sensing Range, Field of View and Orientation

    Page(s): 19 - 24
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (277 KB) |  | HTML iconHTML  

    The directional sensor placement problem is an essential part of any planning model for directional wireless sensor networks. Its goal is to find an optimal subset of locations where directional sensors should be placed so that the total network cost is minimized while the requirements of coverage and connectivity are satisfied. Directional sensors are characterized by three important parameters: sensing range, field of view and orientation. These parameters have significant impact on the overall cost of the directional sensor network. In this paper, we present an integer linear programming formulation for the directional sensor placement problem in which the goal is to minimize the network cost by appropriately choosing the values of the above parameters for each sensor to be installed in the sensor field. We show the viability and effectiveness of the proposed model through numerical results. View full abstract»

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  • SOLIST or How to Look for a Needle in a Haystack? A Lightweight Multi-overlay Structure for Wireless Sensor Networks

    Page(s): 25 - 31
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (3537 KB) |  | HTML iconHTML  

    In this paper, we consider sensor database systems. Sensors are attached to objects and queries on the objects are operated at the sensor network level. Although queries to such a system might be extremely complex, ensuring efficiently basic functionalities such as broadcast or anycast without any central element is not trivial. In this paper, we provide a suite of *-cast (anycast, k-cast, broadcast) functionalities in a fully decentralized manner. More specifically, we present the design and evaluation of SOLIST, a multi-layer structure for sensors, largely inspired from structured peer-to-peer systems providing such functionalities. The main goal of SOLIST is to limit the overall energy consumption. A type is associated to each sensor, and the *-cast functionalities are implemented at a type granularity regardless of the number of types and their distribution within the network. A typical use of such a system is sensor-based stock management. We evaluate SOLIST through simulations and show that SOLIST achieves a reasonable trade-off between performance and energy consumption. View full abstract»

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  • On Gateway Selection Protocol for DYMO-Based MANET

    Page(s): 32 - 37
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (532 KB) |  | HTML iconHTML  

    The coupling of mobile ad-hoc networks (MANETs) and the Internet is gaining attention by researchers working towards future ubiquitous computing environments. In this work, we focus on the situation that occurs when specialized, sensitive data are sent to the Internet from MANET nodes. These special data types are especially susceptible to security risks such as information leak and data falsification. Therefore, it is necessary for such special data to be forwarded by a secure/trusted gateway which is under control of a trusted network administrator. However, we assume there can be multiple gateways deployed in a MANET, where the cost ineffectiveness makes it difficult for a network administrator to simultaneously manage every gateway. Because of the risk of forwarding special data through an unmaintained gateway, we propose a routing protocol which allows a source node to have all data forwarded to the Internet through a trusted gateway. To achieve desirable performance, we improve upon one of the newest routing protocols, Dynamic MANET On-demand (DYMO). Through simulations, we evaluated our proposal in comparison with the conventional DYMO protocol. The results show that our proposal achieves performance allowing MANET source nodes to choose gateways for specific data. View full abstract»

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  • AVERT: Adaptive SerVicE and Route Discovery ProTocol for MANETs

    Page(s): 38 - 43
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (349 KB) |  | HTML iconHTML  

    In the past few years there has been increasing research interest in service discovery protocols for mobile ad hoc networks (MANET). The most promising approaches so far address energy efficiency by merging the service discovery process with the routing process. Actually the service information is piggy-backed into routing messages, so that a node is simultaneously informed of available services and of routes towards the corresponding service providers. This cross layering leads to improved adaptation to the network conditions and at the same time to significant energy savings. Those savings are infeasible if the two processes are implemented separately, because then each one would have to use its own messages and create additional (if not) redundant network overhead. In this paper we propose such a hybrid adaptive protocol for energy consumption-avert users. This protocol, named AVERT, is based on the independent zone routing framework (IZR) and has the ability to allow each node to adapt its zone range (similarly to the way it is done in IZR). We also add a mechanism to adapt the sending rate of proactive messages on each node based only on local traffic monitoring. Through simulations we show that using this mechanism, the energy efficiency achieved is substantially higher compared to similar hybrid service and route discovery protocols. View full abstract»

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  • Accurately Predicting Residual Energy Levels in MANETs

    Page(s): 44 - 50
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (260 KB) |  | HTML iconHTML  

    To support energy-efficient routing, accurate state information about energy level should be available. But due to bandwidth constraints, communication costs, high loss rate and the dynamic topology of MANETs, collecting and maintaining up-to-date state information is a non-trivial task. In this work, we use Optimized Link State Routing (OLSR) as the underlying routing protocol and focus on residual energy level as QoS metric, which has been used for routing decisions in many energy-efficient routing protocol proposals. Our experiments show that nodes have at best imprecise state information, especially under high traffic rates. We propose and evaluate two additional techniques to reduce inaccuracies and compare them against the basic OLSR protocol. These techniques show significant improvements in accuracy levels. In particular, a technique we call Smart Prediction achieves highly accurate perceived residual energy levels under all traffic loads, mobility scenarios, and radio models. View full abstract»

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  • A Dynamic Energy Efficient Clustering Algorithm for MANETs

    Page(s): 51 - 56
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (459 KB) |  | HTML iconHTML  

    This paper proposes a dynamic energy efficient clustering algorithm for mobile ad hoc networks (MANETs). The proposed algorithm elects first the nodes that have a higher energy and less mobility as cluster-heads, then periodically monitors the cluster-heads' energy and locally alters the network topology or the clusters to increase the network lifetime by reducing the energy consumption of the suffering cluster-heads. The algorithm employs two dynamically-computed energy thresholds: a yellow threshold that is used to achieve some sort of local load balancing by distributing the load equally among the adjacent cluster-heads, and a red threshold that is used to trigger local re-clustering in the network. Simulation results show that the proposed algorithm outperformed the weight clustering approach found in the literature. View full abstract»

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