1,721,204 research outputs found
A Multi-service Group Key Management Scheme for Stateless Receivers in Wireless Mesh Networks
No full textWireless mesh networks facilitate the development of the many group oriented applications by extending the coverage area of the group communication. Group communication in a wireless mesh network is complicated due to dynamic intermediate mesh points, access control for communications between different administrative domains, and the absence of a centralized network controller. In this study, we propose a topology-matching decentralized multi-service group key management scheme for wireless mesh networks. It allows service providers to update and deliver their group keys to valid members in a distributed manner using the identity-based encryption scheme. The analysis result indicates that the proposed scheme has advantages with regard to the rekeying cost and storage overhead for a member and a mesh point in multi-sender group communication environments. The stateless property is also achieved such that a stateless member, who could not be constantly online, can easily decrypt the rekeying messages without recording the past history of transmission
A Decentralized Multi-Group Key Management Scheme
No full textScalability is one of the most important requirements for secure multicast in a multi-group environment. In this study, we propose a decentralized multi-group key management scheme that allows each multicast group sender to control the access to its group communication independently. Scalability is enhanced by local rekeying and inter-working among different subgroups. The group key secrecy and backward/forward secrecy are also guaranteed
Punctuated Equilibria in Simple Genetic Algorithms for Functions of Unitation
No full textDuring a genetic search, the population may get stuck in a local optimum. The population can escape from this after a long duration. This phenomenon is called punctuated equilibrium. The punctuated equilibria observed in nature and computational ecosystems are known to be well described by diffusion equations. In this paper, simple genetic algorithms are theoretically analyzed to show that they can also be described by a diffusion equation when fitness is the function of unitation. Using theoretical results on the diffusion equation, the duration of equilibrium is shown to be exponential of such parameters as population size, 1/(mutation probability), and potential barrier. This is corroborated by simulation results for one-dimensional bistable potential landscapes with one local optimum and one global optimum
Autonomous clustering scheme for wireless sensor networks using coverage estimation-based self-pruning
No full textEnergy-efficient operations are essential to prolonging the lifetime of wireless sensor networks. Clustering sensor nodes is one approach that can reduce energy consumption by aggregating data, controlling transmission power levels, and putting redundant sensor nodes to sleep. To distribute the role of a cluster head, clustering approaches should be based on efficient cluster configuration schemes. Therefore, low overhead in the cluster configuration process is one of the key constraints for energy-efficient clustering. In this paper, we present an autonomous clustering approach using a coverage estimation-based self-pruning algorithm. Our strategy for clustering is to allow the best candidate node within its own cluster range to declare itself as a cluster head and to dominate the other nodes in the range. This same self-declaration strategy is also used in the active sensor election process. As a result, the proposed scheme can minimize clustering overheads by obviating both the requirements of collecting neighbor information beforehand and the iterative negotiating steps of electing cluster heads. The proposed scheme allows any type of sensor network application, including spatial query execution or periodic environment monitoring, to operate in an energy-efficient manner
Wireless packet fair queueing algorithms with link level retransmission
No full textin order to provide quality of service to wireless networks, a number of wireless fair queueing algorithms have recently been proposed. They, however, require perfect channel prediction before transmission and rarely consider algorithms under the link layer. Instead of perfect channel prediction, most wireless systems adopt the Link Level Retransmission (LLR) algorithm within the link layer for recovering channel errors. However, the LLR algorithm does not work well with the previous prediction-based wireless fair queueing algorithms. Therefore, we propose a new wireless fair queueing algorithm, Wireless Fair Queueing with Retransmission (WFQ-R), which is well matched with the LLR algorithm and does not require channel prediction. In the WFQ-R algorithm, the share consumed by retransmission is regarded as a debt of the retransmitted flow to the other flows. So, the WFQ-R algorithm achieves wireless fairness with the LLR algorithm by penalizing flows that use wireless resources without permission in the link layer. Through analyses, we proved that the WFQ-R algorithm guarantees throughput and delay fairness. Through simulations, we showed that our WFQ-R algorithm maintains fairness adaptively. Furthermore, our WFQ-R algorithm is able to achieve flow separation and compensation. (c) 2004 Elsevier B.V. All rights reserved
THE PM221 INTERCONNECTION NETWORK
No full textThis work was supported in part by The Ohio State University Seed Grant 221630
Design and analysis of a fair scheduling algorithm for QoS guarantees in high-speed packet-switched networks
No full textHandoff procedure for seamless service in IP and OFDM based 4G mobile systems
No full textWe propose an efficient and practical seamless handoff scheme for 4G mobile systems based on IP and OFDM. The seamless handoff scheme obtains the physical channel for handoff in a contention-free manner with pre-synchronization and pre-forwarding IP contexts. As a result, it thoroughly decreases the physical channel blocking time as well as IP layer context-switching time to minimize total handoff delay
Free submesh list strategy: A best fit submesh allocation in mesh connected multicomputers
No full textThe submesh allocation problem is to recognize and locate a free submesh that can accommodate a request for a submesh of a specified size. In this paper, we propose a new best-fit submesh allocation strategy. The proposed strategy maintains and uses a free submesh list to get global information for free submeshes. For an allocation request, the proposed strategy tries to allocate a best-fit submesh which causes the least amount of potential processor fragmentation so as to reserve the large free submeshes as many as possible for later requests. For this purpose, we introduce a novel function for quantifying the degree of potential fragmentation of submeshes. The proposed strategy has the complete submesh recognition capability. Extensive simulation is carried out to compare the proposed strategy with the previous strategies and it is shown that the proposed strategy exhibits the best performance. © World Scientific Publishing Company
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