In many practical scenarios, nodes gathering at points of interest yield sizable connected components (clusters), which sometimes comprise the majority of nodes. While recent analysis of mobile networks focused on the...
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ISBN:
(纸本)9781450301831
In many practical scenarios, nodes gathering at points of interest yield sizable connected components (clusters), which sometimes comprise the majority of nodes. While recent analysis of mobile networks focused on the process governing node encounters ("contacts"), this model is not particularly suitable for gathering behavior. In this paper, we propose a model of stochastic coalescence (merge) and fragmentation (split) of clusters. We implement this process as a Markov chain and derive analytically the exact stationary distribution of cluster size. Further, we prove that, as the number of nodes grows, the clustering behavior converges to a mean field, which is obtained as a closed-form expression. This expression translates the empirical merge and split rate of a scenario, a microscopic property, to an important macroscopic property-the cluster size distribution-with surprising accuracy. We validate all results with synthetic as well as real-world mobility traces from conference visitors and taxicabs with several thousand nodes. Copyright 2010 ACM.
Scheduling through wireless shared channels is a very challenging problem because of each user's link-state variations through time. The challenge lies in the support of the quality of service (QoS) of each user u...
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ISBN:
(纸本)9783800729616
Scheduling through wireless shared channels is a very challenging problem because of each user's link-state variations through time. The challenge lies in the support of the quality of service (QoS) of each user under the uncertainty of channel behavior. This problem becomes even more difficult for some of the 2.5G and 3.5G network architectures (e.g EDGE,HSDPA, HDR) where the supported transmission rate can take multiple values and the channel can not be modeled by the traditional ON-OFF model. In this paper we propose Expo-pred-wei, a new scheduling algorithm, which take advantage of the channel variations in order to maximize the total cell throughput and at the same time to preserve, in an efficient way, a minimum QoS for each user. In contrast to other proposed algorithms, our algorithm exhibits very good performance in a wide set of traffic scenarios including Real-Time (RT) or Non-Real-Time (NRT) traffic as well as mixed RT and NRT traffic.
This paper presents a novel approach to detecting and resolving service interactions in run-time of the Parlay-Based converged network (PCN) with service intentions. In this paper, we focus on feature interactions in ...
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This paper presents a novel approach to detecting and resolving service interactions in run-time of the Parlay-Based converged network (PCN) with service intentions. In this paper, we focus on feature interactions in the service layer and propose a novel approach of detecting and resolving feature interactions in run-time based on behavior context of services with the Parlay APIs in the Parlay-based Next generation intelligent network (NGIN). Some theory analysis of the approach is given. With the experiment prototype of the architecture of Parlay-based NGIN as well as the two entities of the Telestar application server entity (TASE) and the Telestar parlay gateway entity (TPGE), we extend the TASE of platform with the Service interaction manager (SIM) to manage the service interactions. At last, some experiment results are given.
We present two local approaches that yield polynomial-time approximation schemes (PTAS) for the Maximum Independent Set and Minimum Dominating Set problem in unit disk graphs. The algorithms run locally in each node a...
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ISBN:
(纸本)9781595930927
We present two local approaches that yield polynomial-time approximation schemes (PTAS) for the Maximum Independent Set and Minimum Dominating Set problem in unit disk graphs. The algorithms run locally in each node and compute a (1 + Ε)-approximation to the problems at hand for any given Ε > 0. The time complexity of both algorithms is O(TMIS + log*n/ΕO(1)), where TMIS is the time required to compute a maximal independent set in the graph, and n denotes the number of nodes. We then extend these results to a more general class of graphs in which the maximum number of pair-wise independent nodes in every r-neighborhood is at most polynomial in r. Such graphs of polynomially bounded growth are introduced as a more realistic model for wireless networks and they generalize existing models, such as unit disk graphs or coverage area graphs. Copyright 2005 ACM.
Ring Ingress Aggregated with Spatial Reuse (RIAS) has been proposed as a fairness model for Resilient Packet Rings (RPR) where available bandwidth is allocated among traffic flows in max-min sense. In this paper, we s...
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Resilient Packet Ring (RPR), which is being standardized as IEEE 802.17, is a new Medium Access Control (MAC) protocol for high-speed metro-area ring networks. RPR supports spatial reuse and therefore requires to ensu...
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In this paper the ETHMICS project with its novel network interface is introduced. The requirements of the communication system are elaborated, based on the functionality described. The implementation of the Interactio...
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Intrusion or misbehaviour detection systems are an important and widely accepted security tool in computer and wireless sensor networks. Their aim is to detect misbehaving or faulty nodes in order to take appropriate ...
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ISBN:
(纸本)1595935541
Intrusion or misbehaviour detection systems are an important and widely accepted security tool in computer and wireless sensor networks. Their aim is to detect misbehaving or faulty nodes in order to take appropriate countermeasures, thus limiting the damage caused by adversaries as well as by hard or software faults. So far, however, once detected, misbehaving nodes have just been isolated from the rest of the sensor network and hence are no longer usable by running applications. In the presence of an adversary or software faults, this proceeding will inevitably lead to an early and complete loss of the whole *** this reason, we propose to no longer expel misbehaving nodes, but to recover them into normal operation. In this paper, we address this problem and present a formal specification of what is considered a secure and correct node recovery algorithm together with a distributed algorithm that meets these properties. We discuss its requirements on the soft- and hardware of a node and show how they can be fulfilled with current and upcoming technologies. The algorithm is evaluated analytically as well as by means of extensive simulations, and the findings are compared to the outcome of a real implementation for the BTnode sensor platform. The results show that recovering sensor nodes is an expensive, though feasible and worthwhile task. Moreover, the proposed program code update algorithm is not only secure but also fair and robust. Copyright 2007 ACM.
Stationary properties of node distribution and speed distribution for random direction model were studied. Firstly, geometric probability was applied to analyze stationary node distribution. A closed form probability ...
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McCullagh-Barreto key agreement protocol and its variant achieve perfect forward security and key generation center （KGC） forward security, but provide no resistance to key compromise impersonation attack （KCI att...
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McCullagh-Barreto key agreement protocol and its variant achieve perfect forward security and key generation center （KGC） forward security, but provide no resistance to key compromise impersonation attack （KCI attack）. In this paper, we give a formal treatment of key compromise impersonation （KCI） attack and define the security notion against it. Then an variant of McCullagh-Barreto protocol is presented with only one more Hash operation. The improved protocol preserves perfect forward security and KGC forward security, and furthermore is proved to be secure against KCI attack under k-Gap-BCAA1 assumption.
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