查看更多>>摘要：Traffic information acquisition system is an essential part of the intelligent transportation system (ITS). This paper presents a novel traffic information acquisition system, i.e., a dynamic traffic information acquisition system based on wireless mesh networks (WMN). The system comprises of probe vehicles and wireless mesh networks. Compared to the conventional systems, it is independent of other network infrastructures and easy to implement. It can acquire the real-time traffic information correctly with lower cost.
查看更多>>摘要：The mining of association rules is one of the primary methods used in telecommunication alarm correlation analysis, of which the alarm databases are very large. The efficiency of the algorithms plays an important role in tackling with large datasets. The classical frequent pattern growth (FP-growth) algorithm can produce a large number of conditional pattern trees which made it difficult to mine association rules in telecommunication environment. In this paper, an algorithm based on layered frequent pattern tree (LFP-tree) is proposed for mining frequent patterns. Efficiency of this algorithm is achieved with following techniques: 1) All the frequent patterns are condensed into a layered structure, which can save memory occupied. The layered structure can not only reduce the mining time but also be very useful for updating the alarm databases. 2) Each alarm item can be viewed as a triple < a, v, t >, in which t is a Boolean variable that shows the item frequent or not. 3) Deleting infrequent items with dynamic pruning can avoid produce conditional pattern sets. Simulation and analysis of algorithm show that it is a valid method with better time and space efficiency, which is adapted to mine association rules in telecommunication alarm correlation analysis.
查看更多>>摘要：This paper proposes a mathematical model for distinguishing services at bit-level. By using correlation analysis, the features of bit flows are extracted. The feature analyses of time division multiplex (TDM) service and Gigabit Ethernet (GE) service are described in detail, and then the performance of the proposed method is evaluated. Both of the undetected probability and the misjudgment probability for GE service are as low as 2% at the average Ethernet frame length of 300 B.
查看更多>>摘要：Network selection mechanisms play a vital role in ensuring quality of service in the heterogeneous multi-access environment. In this article we develop a network selection scheme for an integrated cellular/wireless local area network (WLAN) system to guarantee mobile users being always best connected (ABC). The proposed scheme comprises three parts, with the first detecting the availability of WLAN, while the second applying an analytic hierarchy process (AHP) to decide the relative weights of evaluative criteria set according to user preferences, network condition and service applications, the third normalizing parameters and calculating decision-making index. Simulations conducted in a heterogeneous system with UMTS and wireless LAN reveal that the proposed network selection technique can effectively decide the optimum network through making trade-offs among network condition, user preference, and service application, while avoiding frequent handoffs.
查看更多>>摘要：Hybrid peer-to-peer (P2P) system can improve the performance of the entire system using super-peer. But it is difficult to measure a peer's capability exactly and ensure high reliability of the network. This paper proposes a scheme to solve these problems. Firstly, we present a hybrid P2P network in which the upper layer is Chord network and the lower layer is cluster. Then we provide a strategy to measure a peer's capability so that a cluster can be organized to be a sorting network in which peers are classified into three types: dynamic-super-node (DSN), backup-node (BN) and ordinary-node (ON). In a cluster, DSN and BNs are strongly connected. And based on this, we present an algorithm DSN flood min (DSNFM) to select DSN BN and maintain consensus of the cluster. Furthermore, we do a reliability analysis of the cluster based on churn rate of the network and gathered three rules of thumb from our simulations.
查看更多>>摘要：Currently most wireless sensor network applications assume the presence of single-channel medium access control (MAC) protocols. However, lower sensing range result in dense networks, single-channel MAC protocols may be inadequate due to higher demand for the limited bandwidth. In this paper we proposed a method of multi-channel support for DMAC in Wireless sensor networks (WSNs). The channel assignment method is based on local information of nodes. Our multi-channel DMAC protocol implement channel distribution before message collecting from source nodes to sink node and made broadcasting possible in DMAC. Analysis and simulation result displays this multi-channel protocol obviously decreases the latency without increasing energy consumption.
查看更多>>摘要：Web 2.0 has been becoming the new tendency of the Internet development. In order to get better management of web 2.0 network resource and guarantee of service quality, the architecture and the advantages of web 2.0 over Ajax technology is analyzed, and the impact of Ajax on bandwidth performance of web application is discussed.
查看更多>>摘要：Session initiation protocol (SIP) is one of the most popular protocols these days. There are lots of SIP implementations, but not all of them have good quality, so we need SIP conformance test to verify the conformance between the SIP implementations and SIP related protocols.
查看更多>>摘要：In this paper, we put forward a new classification algorithm based on RGH-Tree search and perform the classification analysis and comparison study. This algorithm can save computing resource and increase the classification efficiency. The experiment shows that this algorithm can get better effect in dealing with three dimensional multi-kind data. We find that the algorithm has better generalization ability for small training set and big testing result.
查看更多>>摘要：The wireless wearable network and wireless body-centric network can assistant to the user anywhere at anytime communicating with wireless components seamlessly. In this paper, the wireless wearable network and wireless body-centric network have been discussed, and the frequency band and human body effect has been estimated. The bluetooth and UWB technology can be used to construct the narrow band and the broad band wireless wearable network and wireless body-centric network separately. Further, the narrow band wireless wearable network and wireless body-centric network based on bluetooth technology has been constructed by integrated planar inverted-F antenna and the communication channel character has been studied by measurement. The results can provide the possibility of producing a prototype radio system that can be integrated with the wearable computers by suitable wireless technologies developed and applied to facilitate a reliable and continuous connectivity between the system units.
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