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Mobile Computing, IEEE Transactions on

Issue 1 • Date Jan.-March 2003

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Displaying Results 1 - 7 of 7
  • Policy-driven personalized multimedia services for mobile users

    Publication Year: 2003 , Page(s): 16 - 24
    Cited by:  Papers (8)  |  Patents (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (2368 KB) |  | HTML iconHTML  

    This paper proposes an agent-based service provisioning system for mobile users. It describes a set of cooperative agents distributed over different sites that work together to provide personalized services for mobile users over the Internet. Users moving outside the office are able to maintain an off ice-like environment at home, or at temporary locations such as a meeting at another company, a business trip, or a hotel. Agents representing the end-users and the system agents engage in a negotiation process to facilitate access to personalized services at other sites. This access is obtained in accordance with the users' home policies as well as those at their current location. An Adaptive Service Presentation agent is used to adapt the service presentation to the capabilities of the users' workstations, laptops, phones, PDAs, or other devices. This work is conducted in Canada as part of the Mobile Agent Alliance project involving the University of Ottawa, the National Research Council, and the Mitel Corporation. View full abstract»

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  • Self-organized public-key management for mobile ad hoc networks

    Publication Year: 2003 , Page(s): 52 - 64
    Cited by:  Papers (225)  |  Patents (2)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (2128 KB) |  | HTML iconHTML  

    In contrast with conventional networks, mobile ad hoc networks usually do not provide online access to trusted authorities or to centralized servers, and they exhibit frequent partitioning due to link and node failures and to node mobility. For these reasons, traditional security solutions that require online trusted authorities or certificate repositories are not well-suited for securing ad hoc networks. We propose a fully self-organized public-key management system that allows users to generate their public-private key pairs, to issue certificates, and to perform authentication regardless of the network partitions and without any centralized services. Furthermore, our approach does not require any trusted authority, not even in the system initialization phase. View full abstract»

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  • Efficient PDA synchronization

    Publication Year: 2003 , Page(s): 40 - 51
    Cited by:  Papers (15)  |  Patents (10)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1260 KB) |  | HTML iconHTML  

    Modern personal digital assistant (PDA) architectures often utilize a wholesale data transfer protocol known as "slow sync" for synchronizing PDAs with personal computers (PCs). This approach is markedly inefficient with respect to bandwidth usage, latency, and energy consumption since the PDA and PC typically share many common records. We propose, analyze, and implement a novel PDA synchronization scheme (CPIsync) predicated upon previous information-theoretic research. The salient property of this scheme is that its communication complexity depends on the number of differences between the PDA and PC, and is essentially independent of the overall number of records. Moreover, our implementation shows that the computational complexity and energy consumption of CPIsync is practical and that the-overall latency is typically much smaller than that of slow sync or alternative synchronization approaches based on Bloom (1970) filters. Thus, CPIsync has potential for significantly improving synchronization protocols for PDAs and, more generally, for heterogeneous networks of many machines. View full abstract»

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  • Performance analysis of a preemptive and priority reservation handoff scheme for integrated service-based wireless mobile networks

    Publication Year: 2003 , Page(s): 65 - 75
    Cited by:  Papers (73)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (2219 KB) |  | HTML iconHTML  

    We propose an analytical model for integrated real-time and non-real-time services in a wireless mobile network with priority reservation and preemptive priority handoff schemes. We categorize the service calls into four different types, namely, real-time and non-real-time service originating calls, and real-time and non real-time handoff service request calls. Accordingly, the channels in each cell are divided into three parts: one is for real-time service calls only, the second is for non-real-time service calls only, and the last one is for overflow of handoff requests that cannot be served in the first two parts. In the third group, several channels are reserved exclusively for real-time service handoffs so that higher priority can be given to them. In addition, a realtime service handoff request has the right to preempt non-real-time service in the preemptive priority handoff scheme if no free channels are available, while the interrupted non-real-time service call returns to its handoff request queue. The system is modeled using a multidimensional Markov chain and a numerical analysis is presented to estimate blocking probabilities of originating calls, forced termination probability, and average transmission delay. This scheme is also simulated under different call holding time and cell dwell time distributions. It is observed that the simulation results closely match the analytical model. Our scheme significantly reduces the forced termination probability of real-time service calls. The probability of packet loss of non-real-time transmission is shown to be negligibly small, as a non-real-time service handoff request in waiting can be transferred from the queue of the current base station to another one. View full abstract»

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  • Optimal location area design to minimize registration signaling traffic in wireless systems

    Publication Year: 2003 , Page(s): 76 - 85
    Cited by:  Papers (21)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (3091 KB) |  | HTML iconHTML  

    A new scheme is developed for optimal location area design in wireless systems. New algorithms based on intercell traffic prediction and traffic-based cell grouping are used to select the optimal set of cells for location areas (LAs). The expected intercell movement patterns of mobiles are determined by using the new intercell traffic prediction algorithm. Further, the cells are partitioned into LAs by applying the new traffic-based cell grouping algorithm where the cell pairs with higher intercell mobile traffic are grouped into the same LA. Hence, the inter-LA mobile traffic is decreased by increasing the intra-LA mobile traffic. Experimental results show that this cell grouping algorithm reduces the number of location updates by 27 percent to 36 percent on average compared to proximity-based cell grouping schemes. View full abstract»

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  • Quantitative analysis of a hybrid replication with forwarding strategy for efficient and uniform location management in mobile wireless networks

    Publication Year: 2003 , Page(s): 3 - 15
    Cited by:  Papers (10)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (543 KB) |  | HTML iconHTML  

    A location management scheme in wireless networks must effectively handle both user location update and search operations. Replication and forwarding are two well-known techniques to reduce user search and update costs, respectively, with replication being most effective when the call to mobility ratio (CMR) of the user is high, while forwarding is most effective when the CMR value is low. Thus, based on the user's CMR, the system can adopt a CMR threshold-based scheme such that if the user's CMR is lower than a threshold, then the system applies the forwarding scheme; otherwise, it applies the replication scheme. Applying different location management schemes based on per-user CMR values introduces undesirable high complexity in managing and maintaining location- related information stored in the system as different system support mechanisms must be applied to different users. In this paper, we quantitatively analyze a hybrid replication with forwarding scheme that can be uniformly applied to all users. The most striking feature of the hybrid scheme is that it can determine and apply the optimal number of replicas and forwarding chain length on a per-user basis to minimize the communication cost due to location management operations while still being able to use the same data structure and algorithm to execute location management operations in a uniform way for all users. We develop a stochastic Petri net model to help gather this information and show how the information obtained statically can be used efficiently by the system at runtime to determine the optimal number of replicas and forwarding chain length when given a use user's profile. We show that the proposed hybrid scheme outperforms both pure replication and forwarding schemes, as well as the CMR threshold-based scheme under all CMR values. View full abstract»

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  • The critical transmitting range for connectivity in sparse wireless ad hoc networks

    Publication Year: 2003 , Page(s): 25 - 39
    Cited by:  Papers (142)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (651 KB) |  | HTML iconHTML  

    We analyze the critical transmitting range for connectivity in wireless ad hoc networks. More specifically, we consider the following problem: assume n nodes, each capable of communicating with nodes within a radius of r, are randomly and uniformly distributed in a d-dimensional region with a side of length l; how large must the transmitting range r be to ensure that the resulting network is connected with high probability? First, we consider this problem for stationary networks, and we provide tight upper and lower bounds on the critical transmitting range for one-dimensional networks and nontight bounds for two and three-dimensional networks. Due to the presence of the geometric parameter l in the model, our results can be applied to dense as well as sparse ad hoc networks, contrary to existing theoretical results that apply only to dense networks. We also investigate several related questions through extensive simulations. First, we evaluate the relationship between the critical transmitting range and the minimum transmitting range that ensures formation of a connected component containing a large fraction (e.g., 90 percent) of the nodes. Then, we consider the mobile version of the problem, in which nodes are allowed to move during a time interval and the value of r ensuring connectedness for a given fraction of the interval must be determined. These results yield insight into how mobility affects connectivity and they also reveal useful trade offs between communication capability and energy consumption. View full abstract»

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Aims & Scope

Mobile Computing, as proposed in this Transactions, focuses on the key technical issues related to (a) architectures, (b) support services, (c) algorithm/protocol design and analysis, (d) mobile environments, (e) mobile communication systems, (f) applications, and (g) emerging technologies.

Full Aims & Scope

Meet Our Editors

Editor-in-Chief
Prasant Mohapatra
Interim Vice-Provost and CIO
Professor, Dept. Computer Science
University of California, Davis, USA
pmohapatra@ucdavis.edu