Earticle

According to the defects that community detection algorithm in unknown complex networks has a pre-parameter. We propose Adaptive Label Propagation Algorithm (ALPA) to detect community structures in complex networks. The ALPA algorithm find out all disjoint Maximal Clique (MC) and let each MC share the identical weight and unique label so as to reduce the redundant labels and uncontrollable factors. The stability of ALPA algorithm is enhanced by synchronous update during iterations. Meanwhile it will converge easily due to the termination condition that all of the vertexes have the label. During iterations we use the adaptive threshold method to overcome the pre-parameter limitation. Compared with other community detection algorithms in synthetic networks and real networks, our experiments show that ALPA algorithm not only improves the tolerance of mixing parameter, but also enhances its robustness.

New advancements in wireless sensor networks (WSNs) make it a significant technology in research and academic community. Because of its ad-hoc and minimum infrastructure nature, it has gained lot of attention by researchers in past few years. In WSN, sensor nodes are small sized with limited energy processors which have most important task in WSN. They gather data, process it and further send it to the destination. In many applications like rescue operations, military tracking, environment monitoring etc. it is required that location of sensors must be known else the information collected gets no meaning. So, many localization algorithms are introduced in WSN which meet the resource, hardware, cost and energy constraints of WSN. Range free localization techniques are best suited for these requirements of network. DV-HOP and APIT range free techniques have gained attention in most of research efforts. So,in this paper ,performance of these techniques is evaluated on the basis of accuracy obtained while implementeing them in WSN . Detail analysis of localization error is done by considering different network parameters effecting it directly. Further structured deployment of anchors is proposed that gave more reliable results.

With the development of Internet technology, network based activities such as e-commerce, internet voting and e-government, etc. have become increasingly frequent, People are increasingly concerned about the identity of network activity, content and other private information. In order to protect user privacy in network communications, governments, companies, universities and research institutes are pushing the research and development of the onion routing systems (TOR). Tor is the most popular anonymous communication system currently, which is based on technology of the second-generation onion routing. Tor has a low latency, encrypted data transmission, secure channel, etc., which are widely used in anonymous Web browsing, instant messaging, Secure Shell Client (SSH), etc. However, the development of the onion routing systems is constrained by complicated code factors. According to this situation, this paper put forward an overall architecture of TOR code, which contains Application Needs, Code Analysis and Improvement. This paper summarizes the overall framework of tor code structure, in order to make the code structure clearer, the whole code module is divided into several sub modules, using the function call diagram and UML diagram illustrates the main function of each module and call relation between each module. This paper gives code analysis for anonymous architecture of TOR. Finally, this paper put forward the improvement of routing algorithms of TOR. Based on this paper, a method has been created which is used to understand the tor code easily. Furthermore, systematic analysis of the tor code provided in this paper aims to research the working principle and promote the further development of the onion routing.

In order to solve such problems as large delay and large energy consumption in current wireless sensor network (WSN) during data collection, a network structure for WSN data collection based on delay perception is designed in this article. Firstly, the tree structure thought is introduced therein to divide WSN sensor nodes into multiple single-layer clusters with different sizes so as to construct a new network structure, thus to improve the topological structure and enable the cluster heads to complete the data communication in an interlaced mode as well as significantly reduce the delay during data collection; secondly, the model for calculating the delay and the energy consumption during WSN data collection is established in this article; thirdly, Top-Down technology is introduced therein to design the network structure formation algorithm, thus to optimize the energy consumption of the data collection mechanism through the communication distance minimization. The experiment shows: compared with existing network structure for WSN data collection, the proposed network structure can not only effectively reduce the delay during WSN data collection, but also maintain the whole communication energy consumption at a relatively low level.

Mobile service providers allow their customers to use roaming services when they travel to other countries. In the standard mobile call setup procedures, multiple VPMN MSISDNs cannot be provided to the roamers. Also, call setup to the roamer is indirectly routed through the home network of the roamer, which results in the usage of expensive international carrier’s trunks. In this paper, we propose a software framework that provides multiple VPMN MSISDNs in a UMTS. The proposed framework solves the indirect routing problem and can be easily deployed to mobile operators since it does not modify standard telecommunication protocols.

Data fusion application is one of the most popular applications in Wireless sensor networks (WSNs). Time synchronization is an important technology for data fusion applications due to its necessary for data fusion in the networks. Aimed at reliable time synchronization performance, this paper proposes a novel two-way time synchronization protocol (NTSP). Combing node’s clock model and two-way packet exchange mechanism, NTSP makes time synchronization protocol more precise and much steadier. NTSP adopts simulated annealing (SA) algorithm to defend random noise and malicious delay attacks. Network simulations are carried out to analyze performances of NTSP on time synchronization accuracy, convergent rate and defensive degree for malicious delay attacks. Comparing to traditional time synchronization protocols, NTSP is an effective time synchronization protocol in WSNs.