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Reasoning About Context-Awareness in the Presence of Mobility

Electronic Notes in Theoretical computer science 2004年 97卷 259-276页

作者： Christine Julien Jamie Payton Gruia-Catalin Roman Mobile Computing Laboratory Department of Computer Science and Engineering Washington University Saint Louis MO USA

Context-awareness is emerging as an important computing paradigm designed to address the special needs of applications that must accommodate or exploit the highly dynamic environments that occur in the presence of physical or logical mobility. A number of formal models are available for reasoning about concurrency. Models designed to capture the specifics of mobility are fewer but still well represented (e.g., mobile Ambients, π-Calculus, and mobile UNITY). These models do not, however, provide constructs necessary for explicit modeling of context-aware interactions. This paper builds upon earlier efforts on state-based formal reasoning about mobility and explores the process by which a model such as mobile UNITY can be transformed to explicitly capture context- awareness. Starting with an examination of the essential features of context-aware systems, this paper explores a range of constructs designed to facilitate a highly decoupled style of programming among context-aware components. The result of this exploration is a model called Context UNITY .

关键词： Formal methods context-awareness mobile computing UNITY Context UNITY shared variables

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Using hybrid selection schemes to support QoS when providing multihop wireless Internet access to mobile ad hoc networks

Using hybrid selection schemes to support QoS when providing...

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International Conference on Quality of Service in Heterogeneous Wired/Wireless Networks (QSHINE)

作者： H. Ammari H. El-Rewini Mobile Computing and Parallel Processing Laboratory Computer Science and Engineering Department Southern Methodist University Dallas TX USA

The quality of service (QoS) of wireless Internet access that could be provided to multihop wireless networks, so-called mobile ad hoc networks (MANETs), is highly dependent on the quality of the design of the intermediate facility that will integrate MANET and the Internet. This facility is equipped with a hybrid mechanism being able to fulfill the working requirements of MANET and the Internet so that it can connect to either one of these orthogonal network architectures. The architecture that we propose in order to provide MANET nodes with Internet access utilizes fixed gateways (or access points) and exploits the mobility capability of additional mobile ones. Since Internet access to MANET nodes is provided through mobile gateways, the quality of such service depends on the selection procedure used by MANET nodes to choose the most convenient mobile gateways and register with. In this paper, we suggest to use a hybrid criterion based on the weighted sum of the Euclidean distance between MANET nodes and mobile gateways, and the load of mobile gateways, defined as the number of MANET nodes currently registered with them. Moreover, the sum of the weights is normalized to one, where each weight measures the level of interest of the corresponding criterion in the hybrid one. Simulation results show that the hybrid criterion has an impact on the quality of wireless Internet access service depending on the level of interest assigned to each of the Euclidean distance and load criteria in the weighted sum.

关键词： Spread spectrum communication IP networks mobile ad hoc networks Quality of service Web and internet services Routing protocols Euclidean distance Access protocols mobile computing computer networks

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Integration of mobile ad hoc networks and the Internet using mobile gateways

Integration of mobile ad hoc networks and the Internet using...

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International Symposium on Parallel and Distributed Processing (IPDPS)

作者： H. Ammari H. El-Rewini Mobile Computing and Parallel Processing Laboratory Computer Science and Engineering Department School of Engineering Southern Methodist University Dallas TX USA Mobile Computing and Parallel Processing Lab Computer Science and Engineering Department School of Engineering Southern Methodist University Dallas TX USA

Summary form only given. mobile ad hoc networks (MANET) and the Internet exhibit differences in their network architecture. These differences concern the various sorts of assumptions imposed not only on the structure and topology of the underlying networks, but also on communication patterns of mobile nodes in both networks. Integrating MANET and the Internet into a hybrid network is a challenging problem due to these differences. We propose a three-layer approach that uses both mobile IP and dynamic destination-sequenced distance vector (DSDV) to integrate these two types of networks into a hybrid environment, in order to provide MANET nodes with Internet connectivity and access to the Internet resources. Our approach is based on the use of mobile gateways as an interface between MANET and the Internet. These mobile gateways can use mobile IP when they communicate with the Internet and DSDV when they interact with MANET. We also show the results of several simulation experiments that were conducted to study the integrated environment.

关键词： mobile ad hoc networks IP networks Internet mobile computing computer networks mobile communication Routing protocols Concurrent computing Parallel processing computer science

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A multicast protocol for mobile ad hoc networks using location information

A multicast protocol for mobile ad hoc networks using locati...

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Workshop on Applications and Services in Wireless Networks, ASWN

作者： H. Ammari H. El-Rewini Mobile Computing and Parallel Processing Laboratory Computer Science and Engineering Department School of Engineering Southern Methodist University Dallas TX USA

Multicasting is a one-to-many process by wbich a node can send the same packet to a subset of nodes, called multicast group, which have already registered to the same multicast group address. The goal of this paper is to propose a multicast algorithm for mobile ad hoc networks using location information, where a multicast group is definro with respect to a specific network space area, called millticost domain. A mohile ad hoc network (MANET) is a set of nodes that agrero upon fonning a spontaneous, temporar y network so that they can communicate over wireless Iinks despite the lack of any centraIized administration and any fonn or infrastructure. The proposed algorithm benefits from the location-oriented service offered by a glohal positioning system (GPS), which provides MANET nodes (or nodes for short) with their location information when needed. Moreover, the protocol makes use of the Vorono; diagram properties in order to multicast a packet in a selective manner towards its target multicast dOmain, where ouly a small subset of nodes is involved in the forwarding process. These nodes, called authorized forwarders, are identified from the *** Voronoi graph that a multicast source node or an authorized forwarder constructs based on the location infonnation of its neighborhood as well as the target multicast domain. The analysis bas shown that fhe protocol helps minimize the transmission overhead, which would be caused during the forwarding of a multicast packet, while guaranteeing convergence and correctness. Compared to other existing location-based multicast protocols, the proposed one yields more reduction of transmission overhead and perfonns correctly even with particular MANET topologies. Keywords - Multicasting, mobile ad hoc networks, locationbased service, Voronoi diagmms, global positioning system.

关键词： Multicast protocols mobile ad hoc networks Routing protocols Multicast algorithms Network topology mobile computing computer networks Concurrent computing Parallel processing Laboratories

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Blocking probability analysis in future wireless networks

Blocking probability analysis in future wireless networks

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IEEE International Conference on Communications (ICC)

作者： R. Beaubrun S. Pierre J. Conan Department of Computer Science and Software Engineering Université LAVAL QUE Canada Mobile Computing and Networking Research Laboratory (LARIM) Ecole Polytechnique de Montrèal Montreal Canada

This paper proposes to model each cell of future wireless networks as a G/G/c/c queueing system. As such a model has not been explicitly addressed in the literature, we apply maximum entropy principles to evaluate both traffic distribution and blocking probability within each cell. Analysis of numerical results enables to specify the conditions under which the system offers good quality of service in terms of blocking probability. More specifically, such an analysis reveals that coefficient of variation of call arrivals has more impact over the blocking probability than coefficient of variation of channel holding time.

关键词： Intelligent networks Wireless networks Telecommunication traffic Traffic control Quality of service mobile communication Entropy Context modeling computer science Software engineering

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Secure sharing of tuple spaces in ad hoc settings

Secure sharing of tuple spaces in ad hoc settings

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SecCo'03, First International Workshop on Security Issues in Coordination Models, Languages, and Systems (Satellite Event for ICALP

作者： Handorean, Radu Roman, Gruia-Catalin Mobile Computing Laboratory Computer Science and Engineering Department Washington University Saint Louis MO 63130-4889 United States

Security is emerging as a growing concern throughout the distributed computing community. Typical solutions entail specialized infrastructure support for authentication, encryption and access control. mobile applications executing over ad hoc wireless networks present designers with a rather distinct set of security requirements. A totally open setting and limited resources call for lightweight and highly decentralized security solutions. In this paper we propose an approach that relies on extending an existing coordination middleware for mobility (LIME). The need to continue to offer a very simple model of coordination that assures rapid software development led to limiting extensions solely to password protected tuple spaces and per tuple access control. Password distribution and security are relegated to the application realm. Host level security is ensured by the middleware design and relies on standard support provided by the Java system. Secure interactions among agents across hosts are accomplished by careful exploitation of the interceptor pattern and the use of standard encryption. The paper explains the design strategy used to add security support in LIME and its implications for the development of mobile applications over ad hoc networks. © 2003 Published by Elsevier science B.V.

关键词： Security of data

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Trust negotiation for authentication and authorization in healthcare information systems

Trust negotiation for authentication and authorization in he...

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Annual International Conference of the IEEE Engineering in Medicine and Biology Society (EMBC)

作者： D.K. Vawdrey T.L. Sundelin K.E. Seamons C.D. Knutson Mobile Computing Laboratory Brigham Young University Provo UT USA Internet Security Research Laboratory Department of Computer Science Brigham Young University Provo UT USA

The expanding availability of health information in an electronic format is strategic for industry-wide efforts to improve the quality and reduce the cost of health care. The implementation of electronic medical record systems has been hindered by inadequate security provisions. This paper describes the use of trust negotiation as a framework for providing authentication and access control services in healthcare information systems. Trust negotiation enables two parties with no preexisting relationship to establish the trust necessary to perform sensitive transactions via the mutual disclosure of attributes contained within digital credentials. An extension of this system, surrogate trust negotiation is introduced as a way to meet the security requirements of healthcare delivery systems based on mobile computing devices and wireless communication technologies. These innovative technologies have enormous potential to improve the current state of security in healthcare information systems.

关键词： Authentication Authorization Medical services Information systems Information security Communication system security Industrial electronics Electrical equipment industry Electronics industry Costs

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A mailbox-based scheme for improving mobile IP performance

A mailbox-based scheme for improving mobile IP performance

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International Conference on Distributed computing Systems Workshop

作者： Liang Zhang Jiannong Cao S.K. Das Internet and Mobile Computing Laboratory Department of Computing Hong Kong Polytechnic University Kowloon Hong Kong China Center for Research in Wireless Mobility and Networking Department of Computer Science and Engineering University of Texas Arlington Arlington TX USA

mobile IP route optimization and mobile IP local registration are two approaches to solve performance problems associated with the base mobile IP protocol proposed by IETF. The route optimization scheme solves the triangular routing problem by introducing the binding cache concept. The local registration scheme reduces the large overhead for location management by processing the mobile host's registration request only at a local foreign agent. In this paper, we present a mailbox-based approach to take advantages of both approaches. Each mobile host migrated to a foreign network is associated with a mailbox, which can be decoupled with the owner host, and packets destined to the receiver will be delivered to the mailbox whose address is cached in the sender. Separating mailbox from its owner host allows us to achieve adaptive location management, while at the same time buffering incoming packets in the mailbox located somewhere in the network closer to the receiver reduces the retransmission cost. The dynamic migration of mailbox also eliminates the need of pre-structuring mobility agents into hierarchy which is a necessary in the local registration scheme.

关键词： Home automation Routing Sprites (computer) Waste management Bandwidth Added delay Internet telephony Streaming media Telecommunication traffic Protocols

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Managing uncertain trajectories of moving objects with DOMINO 4

Managing uncertain trajectories of moving objects with DOMIN...

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4th International Conference on Enterprise Information Systems, ICEIS 2002

作者： Trajcevski, Goce Wolfson, Ouri Hu, Cao Lin, Hai Zhang, Fengli Rishe, Naphtali Database and Mobile Computing Laboratory Department of Computer Science Univeristy of Illinois Chicago United States

ISBN: (纸本)9729805067

This work describes the features of the DOMINO (Database fOr MovINg Objects) system, which brings several novelties to the problem of managing moving objects databases. Our robust model of a trajectory captures the inherent parameter of uncertainty of the moving objects location, which impacts both the semantics of spatio - temporal queries and the algorithms for their processing. In DOMINO, we present a set of novel operators which capture the spatial, temporal and uncertainty aspects of a moving object. The operators are implemented as UDFs (User Defined Functions) on top of existing ORDBMS and can be used for answering queries and generating notification triggers. DOMINO's implementation, in which ORDBMS are coupled with other systems, seamlessly integrates several technologies: 1. existing electronic maps are used to generate the trajectory plan on behalf of a mobile user;2. real-time traffic sources are used to automatically update the moving object's trajectories;3. powerful (web-browser) GUI enables users to monitor and pose queries about objects.

关键词： Trajectories

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Challenge: Integrating mobile wireless devices into the computational grid

Challenge: Integrating mobile wireless devices into the comp...

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Proceedings of The Eight Annual International Conference on mobile computing and Networking

作者： Phan, Thomas Huang, Lloyd Dulan, Chris Pervasive Computing Laboratory Computer Science Department The Univ. of California Los Angeles Los Angeles CA 90095 United States Semiconductor Manufacturing International Corp. Shanghai 201203 China Vizional Technologies Inc. Santa Monica CA 90405 United States

ISBN: (纸本)9781581134865

One application domain the mobile computing community has not yet entered is that of grid computing - the aggregation of network-connected computers to form a large-scale, distributed system used to tackle complex scientific or commercial problems. In this paper we present the challenge of harvesting the increasingly widespread availability of Internet-connected wireless mobile devices such as PDAs and laptops to be beneficially used within the emerging national and global computational grid. The integration of mobile wireless consumer devices into the Grid initially seems unlikely due to the inherent limitations typical of mobile devices, such as reduced CPU performance, small secondary storage, heightened battery consumption sensitivity, and unreliable low-bandwidth communication. However, the millions of laptops and PDAs sold annually suggest that this untapped abundance should not be prematurely dismissed. Given that the benefits of combining the resources of mobile devices with the computational grid are potentially enormous, one must compensate for the inherent limitations of these devices in order to successfully utilise them in the Grid. In this paper we identify the research challenges arising from this problem and propose our vision of a potential architectural solution. We suggest a proxy-based, clustered system architecture with favourable deployment, interoperability, scalability, adaptivity, and fault-tolerance characteristics as well as an economic model to stimulate future research in this emerging field.

关键词： Personal computers

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