| 1. |
- Baraër, Christophe, et al.
(författare)
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ExPLoIT : exploiting past location information and transitivity for positioning in mobile sensor networks
- 2007
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Ingår i: 2nd International Conference on Communication Systems Software and Middleware, 2007. - Piscataway, NJ : IEEE Communications Society. - 1424406145
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Konferensbidrag (refereegranskat)abstract
- We present a novel distributed range-free technique called ExPLoIT for estimating geographical location of sensor nodes in mobile sensor networks. ExPLoIT is the first positioning technique that exploits location information at regular nodes in addition to using seeds. The key idea is the notion of confidence that a node has in its location estimate which can be used by other nodes for localization. Using Monte Carlo integration, a node estimates its current location and confidence based on its past location and the location information it receives from its neighbors. Node mobility is exploited to transitively localize the network. Our extensive simulation study shows that our proposal outperforms three other state-of-the-art range-free localization techniques under a wide range of conditions. The strength of ExPLoIT is that it is robust to irregular radio propagation, arbitrary seed and node density, and stochastic seed and node mobility; no special hardware is necessary at sensor nodes.
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| 2. |
- Channakeshava, Karthik, et al.
(författare)
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IP quality of service support for soft real-time applications
- 2005
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Ingår i: Proceedings - RTN 2005, 4th Intl. Workshop on Real-Time Networks (formerly RTLIA. - Magdeburg : Otto-von-Guericke Univ. - 3929757907
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Konferensbidrag (refereegranskat)abstract
- To obtain acceptable timeliness performance for emerging large-scale distributed real-time control applications operating in large IP internetworks, a scalable quality of service (QoS) architecture is needed. In this paper, we propose a scalable QoS architecture (abbreviated as RTQoS) in support of real-time systems, one that implements real-time scheduling at end-hosts and stateless QoS in the core routers. We address challenges and explore potential benefits achieved by integrating network services with real-time systems, through the use of a network testbed. Experimental evaluation demonstrates the RTQoS architecture as a promising approach for soft real-time applications that are subject to time/utility function time constraints and utility accrual optimality criteria.
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| 3. |
- DaSilva, Luiz A., et al.
(författare)
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Network mobility and protocol interoperability in ad hoc networks
- 2004
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Ingår i: IEEE Communications Magazine. - 0163-6804 .- 1558-1896. ; 42:11, s. 88-96
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Tidskriftsartikel (refereegranskat)abstract
- The integration of various network-level functions, including routing, management, and security, is critical to the efficient operation of a mobile ad hoc network. In this article we focus on network mobility (rather than node mobility), implying the movement of entire subnetworks with respect to one another, while individual users initially associated with one such subnetwork may also move to other domains. One example is a battlefield network that includes ships, aircraft, and ground troops. In this "network of networks", subnets (e.g. shipboard networks) may be interconnected via a terrestrial mobile wireless network (e.g., between moving ships). We discuss the design and implementation of a new ad hoc routing protocol, a suite of solutions for policy-based network management, and approaches for key management and deployment of IPsec in a MANET. These solutions, in turn, are integrated with real-time middleware, a secure radio link, and a topology monitoring tool. We briefly describe each component of the solution, and focus on the challenges and approaches to integrating these components into a cohesive system to support network mobility. We evaluate the effectiveness of the system through experiments conducted in a wireless ad hoc testbed.
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| 4. |
- Lindgren, Anders, et al.
(författare)
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Evaluation of queueing policies and forwarding strategies for routing in intermittently connected networks
- 2006
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Ingår i: The 1st International Conference on Communication System Software and Middleware. - Piscataway, N.J. : IEEE Communications Society. - 0780395751 ; , s. 1-10
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Konferensbidrag (refereegranskat)abstract
- Delay tolerant networking (DTN) and more specifically the subset known as intermittently connected networking, is emerging as a solution for supporting asynchronous data transfers in challenging environments where a fully connected end-to-end path between a source and destination may never exist. Message delivery in such networks is enabled via scheduled or opportunistic communication based on transitive local connectivity among nodes influenced by factors such as node mobility. Given the inherently store-and-forward and opportunistic nature of the DTN architecture, the choice of buffer management policies and message forwarding strategies can have a major impact on system performance. In this paper, we propose and evaluate different combinations of queueing policies and forwarding strategies for intermittently connected networks. We show that a probabilistic routing approach along with the correct choice of buffer management policy and forwarding strategy can result in much performance improvements in terms of message delivery, overhead and end-to-end delay.
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| 5. |
- Lindgren, Anders, et al.
(författare)
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Future directions in ad hoc networking research
- 2005
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Ingår i: 5th Scandinavian Workshop on Wireless Ad-hoc Networks. - Stockholm : Wireless at KTH, Royal institute of technology.
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- Much effort has gone into mobile ad-hoc network (MANET) research over the past decade. Yet, even today, mobile ad-hoc networking is seen as a relatively new area of research. The reason for this can be traced to the fact that the maturity in truly understanding these networks is still alarmingly low and actual deployment of these networks rare. In this paper, we investigate the reasons for this lack and suggest ways for overcoming the shortcomings. We then describe four sub-topics in ad hoc networking that have not received much attention, but are crucial for making real deployment of MANETs feasible.
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| 6. |
- Nykvist, Johan, et al.
(författare)
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Modeling connectivity in mobile ad-hoc network environments
- 2006
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Ingår i: Proceedings, 6th Scandinavian Workshop on Wireless Ad-hoc Networks (ADHOC'06). - Stockholm : Wireless at KTH, Royal institute of technology.
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Konferensbidrag (refereegranskat)abstract
- Spatial mobility models are commonly used to evaluate protocol performance in mobile ad-hoc networks. Choosing parameters for such models so that they correspond to the target environments is not trivial. In this paper, we present a temporal connection model that we believe is better suited for the task. We analyze traces from real world adhoc networks in order to create models that correspond to the topological and temporal properties of these networks.
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| 7. |
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| 8. |
- Phanse, Kaustubh, et al.
(författare)
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Modeling and evaluation of a policy provisioning architecture for mobile ad-hoc networks
- 2006
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Ingår i: Journal of Network and Systems Management. - : Springer Science and Business Media LLC. - 1064-7570 .- 1573-7705. ; 14:2, s. 261-278
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Tidskriftsartikel (refereegranskat)abstract
- The ability to dynamically configure mobile ad-hoc network (MANET) devices is critical for supporting complex services such as quality of service (QoS), security and access control in these networks. In our work, we address the problem of policy distribution and provisioning in MANETs. Previously, we have proposed a policy provisioning architecture that enables the operator, e.g., a military command and control center, to maintain a logically centralized control of the network as a whole, while allowing a physically decentralized and self-managing implementation essential for a MANET environment. In this paper, we present an analytical model of the availability of the policy distribution service in a MANET and analyze the performance using stochastic Petri nets (SPNs). We develop the model at two levels of complexity: as a simple Markovian model with Poisson assumptions and as a more accurate non-Markovian model with general distributions obtained using statistical parameterization. We compare and cross-validate the analytical results with simulation and experimental results. Finally, we illustrate the effectiveness of the architecture for managing QoS for soft real-time applications, using an emulated mobile ad-hoc network testbed.
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| 9. |
- Phanse, Kaustubh, et al.
(författare)
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Opportunistic wireless access networks
- 2006
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Ingår i: Proceedings of the 1st international conference on Access networks. - New York : ACM Digital Library. - 1595935134
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Konferensbidrag (refereegranskat)abstract
- Today, intermittent connectivity is common in wireless access networks and it seems like mobile users will have to deal with discontinuous network access in the future. But existing network protocol architectures are not resilient to disruption of communication links and often communication fails when faced with sporadic connectivity. We discuss a new paradigm for wireless access called opportunistic collaborative networking, where communication is disruption-tolerant and wireless devices exploit any opportunity of communication, albeit temporary, to forward messages towards the destination. For developing protocols for these innovative networks requires understanding of their structure and dynamics. We present some results from analysis of real-life traces representing two such mobile network environments with ad-hoc, intermittent connectivity.
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| 10. |
- Phanse, Kaustubh, et al.
(författare)
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Study of IEEE 802.11 wireless networks in harsh environments
- 2006
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Ingår i: Condition Monitoring and Diagnostic Engineering Management. - Luleå : Luleå tekniska universitet. - 9789163188060
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Konferensbidrag (refereegranskat)abstract
- IEEE 802.11 technologies are expected to remain the popular wireless local area networking solution for home and office environments. With growing interest within the process and manufacturing industry to go wireless, these technologies are a natural choice for enabling tetherless control and maintenance. However, the use of IEEE 802.11 suite of protocols for wireless access in unconventional, harsh environments is limited and their behavior and performance in these settings is not yet well understood. A prime example of such a setting is the LKAB underground iron-ore mine in Kiruna, Sweden. LKAB envisions an economical and effective wireless access solution in the mines for increasing automation, e.g., remotely control mining equipment such as mobile loading machines and drilling equipment. In this paper, we present our experiences of operating an IEEE 802.11g based wireless network in the LKAB underground iron-ore mine. Using measurements, we characterize and model the environment and its effect on the performance of higher layer protocols. We derive the theoretical limits of IEEE 802.11g and compare them with our experimental results. We observe a highly reflective environment in the mine, which causes multipath fading and in turn, considerably degrades the maximum achievable throughput in practice.
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