bluuebunny/crossref_metadata_2025_split huggingface dataset:
Secure and Anonymous Source Routing Protocol for Wireless Ad Hoc Networks
Authors: Xu Li , Chen Sisheng 
Published: January 2009

Wireless ad hoc network is formed by a group of mobile hosts that communicate through radio transmissions. In the hostile environment, this kind of network is vulnerable to traffic analysis which allows the adversary to trace the routing messages and the sensitive data packets. So, anonymous routing protocol for ad hoc networks is an important thing and has attracted more and more attention recently. In this paper, we propose a novel, secure, and anonymous source routing, called SADSR (Secure and Anonymous Dynamic Source Routing) based on DSR. During the routing request of the SADSR, in order to hide the identity, the source node uses its current pseudonym to sponsor the routing request. And it uses the hash value of the changing share key between the source and destination as the tag of the destination. Meanwhile, it employs an initialized Bloom Filter as the routing record table to record the route. When the intermediate nodes receive the routing request, it randomly chooses a secret key and adds its identity into the Bloom Filter with seeding the secret key. So, when the destination node receives the routing request, the Bloom Filter has recorded the route information. Because the feature of the pseudonym employed in our scheme, the destination node can authenticate the source node and updates their share secret key when it replies to the routing request. During the routing reply phase, the intermediate node can determine whether it is the router by checking the Bloom Filter in the reply packet. The router applies the pseudonym based signature to protect the message during the routing reply phase, which makes sure that the neighborhood node en route can authenticate the upstream node and does not disclose its identity. SADSR also contains the routing maintenance and secure anonymous data transmission which are separately used by the end-to-end validate mechanism and HMAC strategy. The performance of security and anonymity of SADSR is analyzed by both in theory and simulation. Compared to the other anonymous routing protocols, SADSR is not only an anonymous routing protocol, but also a secure one. It can provide authentication and integrity, anonymous neighborhood, identity anonymity, and route anonymity. The simulation results using NS-2 indicate that though SADSR is a secure and anonymous routing protocol, but the efficiency of SADSR is close to the secure routing protocol SDSR and anonymous routing protocol AnonDSR.
Efficient Data Transmitting Model in Wireless Sensor Networks
Authors: Wang Tian , Dong Weiqing , Wu Lin 
Published: January 2009

Considering the high similarity among sensor data sequences in wireless sensor networks(WSNs), we propose an efficient data transmitting model—EDTM, which optimizes the data collection scheme utilizing the correlation among sensor nodes. The aim of EDTM is to extend the lifetime of the sensor networks as much as possible, meanwhile guaranteeing the accuracy of data provided to the user which is measured by two parameters, error bounds and confidence. To realize this purpose, EDTM exploits the matching relationship, and if some nodes are matching with each other to a certain degree, it selects the optimal representative nodes Vs to undertake the transportation task. Thus, the measurements of some nodes can be substituted and the energy is conserved. A challenge of the matching algorithm is the time drifting and data lost problem. To obtain the real variation curves of sense attribute, we piecewise fit data sequences using least squares and the fitting error is eliminated in the matching estimation. EDTM computes a parameter IDST based on the sensing curves and we prove that according to the IDST we could analyze the matching degree of any two nodes. At the end, the sensor nodes are distributed into matching sets. We also design the optimal representative node selection scheme including three phases. Every node in the matching sets need to send a cmsg packet to sink in order to inform sink its energy cost information. Sink computes each node's parameter L, which reflects the energy consumption and the influence of energy balance of the node, selects Vs, and informs the transmitting node Vs by sending a tmsg packet. In order to test our approach, an experimental simulation has been done over real-world data and the performance of EDTM has been analyzed. The outcome demonstrates the low error ratio of EDTM, and its effectiveness in decreasing the energy cost.
NS2 Extension for Multi-Channel MAC Simulation Model
Authors: Geng-Yu Wei , Hua Wang , Xiao-Xiao Li , Liu-Tong Xu 
Published: January 2009

In order to improve network performance of delay and throughput, an increasing number of networks begin to support multi-channel communications. Although Network Simulator 2 (NS2) has been the dominant network simulation tool, it does not provide native support for multi-channel simulation. Existing works on extending NS2, such as Hyacinth's and Ramon's contributions, show apparent limitations for usage. This paper proposes a novel extension of NS2, named Multi-channel MAC Simulation Model (MMSM), which defines the facilities for multi-channel MAC protocol simulation. This paper describes the initiative, simulation model architecture of MMSM. Based on extensions of NS2 MobileNode architecture, MMSM has features of flexibility of configuration and transparency to the upper layer. MMSM defines one MAC entity associated with a number of NetIF (Network Interface) entities and each NetIF adhered to one channel. So the mobile node has the ability to send and receive packets simultaneously through multiple channels to or from different adjoining nodes. Thus MMSM provides strong support for simulating newly designed multi-channel MAC protocols such as MAC over Multiple Input Multiple Output (MIMO) or MIMO-like mechanisms. MMSM not only makes the specific simulation available, but also keeps the upper layer facilities unchanged as usual when implementing multi-channel simulation. The paper also describes the implementation of MMSM in NS2 (version 2.29). Modifications are carried out both on TCL and on C++ codes. In TCL level ns-mobilenode.tcl and ns-lib.tcl are modified to assemble the multi-channel components and to make TCL scripts to support multi-channel configuration. In C++ level mac.{h,cc}, mobilenode.{h,cc} and channel.{h,cc} are modified to add the channel selection algorithm and to manage the multi-channel node lists. Based on modifications of NS2 described above, researchers can implement their multi-channel MAC protocols conveniently. To validate the implementation of MMSM, two existing MAC protocols in NS-2.29, the Mac802_11 and Tdma, are extended to have the capability of multi-channel processing. Two typical scenarios are chosen to run the simulation on both the multi-channel and the single channel. Simulation results show that the network throughput of multi-channel MAC is enhanced over the single channel MAC, and therefore it proves the multi-channel capability of MMSM.
ePet: A Physical Game Based on Wireless Sensor Networks
Authors: Tan Wei-Hua , Li Wen-Jun , Zheng Yao-Zhan , Zhou Xiao-Cong 
Published: January 2009

This paper describes ePet, a novel multi-player physical game based on the WSN (Wireless Sensor Network). ePet shifts the traditional virtual pet games to the real world, featuring with the popular RPG (Role-Playing Game) elements. The game, capitalizing on the wireless communication, mobile computing, and sensing ability, can be played both indoors and outdoors, and thus gives players a new exciting gaming experience that profits by the blend of real and virtual game elements. The physical game acquires physical interactions among players, which can bring exciting and novel features to the game and more importantly, avoids some problems caused by traditional computer games such as health problems. The WSN is a promising technology for developing physical games. Although there is already some research and applications of WSN based physical games, the major advantages of the WSN (e.g. wireless communication, mobile computing, and sensing ability) are not fully cultivated in these gaming applications. ePet, which takes good advantages of both the WSN and traditional computer games, simulates a pet both indoors and outdoors. The pet has two life modes: Peaceful Life Mode (PLM) and Aggressive Life Mode (ALM). In the PLM, ePet simulates the physiological activities of a real pet such as hunger and easily getting flu when it is cold in the real world. Moreover, the pet can date with other pets to increase its physiological values. In the ALM, the pet is a character of an RPG controlled by the player and the pet can have a fight with other pets, from which the pet gains experience for level up. This ALM is similar to the computer RPG games but relatively novel in WSN based games. All of the above features are enabled by the WSN technology. For the two life modes, a friend-making protocol and an RPG battle protocol are designed respectively. The architecture design and implementation of ePet are described in detailed. Unlike traditional WSN based games, ePet does not need a centralized base station to organize the network. To implement a self-adaptive wireless sensor network in which each node has a similar functionality, and solve the network conflict problems in the WSN communications, a multi-hop communication routing protocol is designed for ePet. Furthermore, a PC application was developed as the game interface, from which players can check out the ePet's properties and interact with ePet. It makes ePet more attractive than traditional WSN based games without losing WSN's advantages.
An Efficient Semantic-Based Search Schema in Unstructured P2P Network
Authors: Sun Xin , Chao Zhao , Liu Yushu , Zhang Lei 
Published: January 2009

How to efficiently organize and manage distributed resources is a critical issue of P2P systems. In this paper, we focus on both the P2P search mechanism and the topology structure of overlay network which are the key factors to dominate the performance of resource search and discovery. We mostly concern these issues as follows: Heterogeneity of nodes in P2P networks. Topology match between the P2P overlay network and the underlying physical network. In general, most peers that hold similar shared resources have similar requirements. We consider all the factors mentioned above, and propose a semantic-based and locality-aware hybrid P2P architecture (SLHP) including the method of model construction and maintenance and the multi-root mechanism to avoid the single point failure. SLHP considers the physical locality and the semantic similarity of the shared resource at the same time, in which nodes are clustered into domains according to the physical distance, and the nodes in a domain are clustered into groups according to the similar shared resource. The physical distance is measured by the RTT value of two peers. The calculation method of semantic similarity is also given. And then a semantic-based search schema is proposed. When the search occurs, the query is forwarded to super peers, and among super peers the query is forwarded to the neighbors who have the most similar shared resource with the query keyword. We also give a proof that according to the algorithm of construction and maintenance of SLHP, it is ensured that the existed resource must be found in theory. The semantic-based search can reduce the number of the transferred messages comparing with the standard flooding scheme, since it only produces k messages each hop, and forward to the most expected peers. Along with the routing indices being optimized continuously, which represents the knowledge of nodes about the entire overlay network, the hit ratio can be improved. Finally, in order to evaluate the performance of semantic-based search schema, three sets of simulations are set up to evaluate the key features of the network topology and semantic-based search algorithm. Experimental results show that the semantic-based search schema can reduce the search space, and get a good tradeoff between the performance and the overhead.
Improving Cluster-Based Peer-to-Peer Systems
Authors: Gong Yadong , Lin Xiaola 
Published: January 2009

To make P2P (Peer-to-Peer) logical overlay network match the physical topology, cluster-based P2P systems have been proposed. In such systems, nodes maintain two types of links: local link and remote link. Node uses local links to cluster nodes with short network distance and the remote link to build connections with some remote nodes according to certain rules. When a query is generated, it is first processed in local cluster (intra-cluster query) based on local links, and if it fails, it will be selectively relayed to other clusters (inter-cluster query) based on remote links. Because the number of nodes and the distance between nodes in local clusters are small compared to the entire P2P network, intra-cluster query processes can get high efficiency just using some simple search methods such as Flooding or Random Walk. Nevertheless, the dynamic character of nodes and decentralized distribution of resources in the systems make the nodes in one cluster difficult to maintain up-to-date resource distribution information in other clusters. Thus, the efficiency of inter-cluster query is limited. In P2P systems, stable nodes have much longer online time, so they have a longer time to let other nodes download resources from them. Also, maintaining resource distribution of stable nodes can cause much less traffic, incurred by the dynamic nature of nodes, than dynamic nodes. Based on the above analysis, we propose the Differentiated Publishing (DiffPublishing) architecture by letting resources of stable nodes serve queries in large areas and having resources of dynamic nodes answer queries in local clusters. In the proposed system, the resources of the stable nodes are indexed by a decentralized topology: service provider overlay. When a query is generated, it is first processed in the local cluster, and if it fails, it will be forwarded to the service provider overlay. Because most resources in P2P systems are provided by a small portion of super nodes that tend to be stable, a high query success rate can be achieved in the service provider overlay. Also, maintaining resource indices of stable nodes can save much traffic caused by the dynamic nature of nodes, so the maintenance cost in service provider overlay is not expensive. Search traffic in the proposed system is dramatically reduced due to the shrunken search scope. More importantly, the proposed DiffPublishing architecture can be easily deployed in existing cluster-based P2P systems to improve their inter-cluster query processes.
Dynamic Coverage Based on Neural Gas Learning Algorithm for Wireless Sensor Network
Authors: Sun Yanjing , Qian Jiansheng , Li Li 
Published: January 2009

With the rapid development of microelectro mechanical systems (MEMS), wireless communications, and information networking and integrated circuits technologies, wireless sensor network technology came into being. For the monitoring of large areas or dangerous region or enemy region, commonly used, such as randomly dropping the sensor nodes, and coverage is one of the main problems to solve for the WSN. Control of the coverage for WSN, can be seen as when the energy of sensor network nodes, wireless communications network bandwidth, network computing ability are limited, through placing the sensor nodes and choosing routing at the network and other means to optimize the allocation of resources of WSN, avoid blind spots in the coverage area, or get in a local minimum value. Covering algorithm needs to consider network connectivity, energy efficiency, dynamics of the network, and other issues. According to the configuration of wireless sensor nodes, coverage is divided into certainty coverage and random coverage. In the actual environment, network topology is unpredictable, and network topology changes complexly, so it seems particularly important to achieve a dynamic coverage. It is a NP problem to achieve optimal coverage for monitoring the area of unfixed and intensive signals, so we made an effective distributed approximation algorithm to ensure that the sensor nodes change rapidly to achieve optimal coverage. Assuming each sensor node can directly communicate with other nearby sensors, have the same sensing range, and have data-processing functions, and move free according to the “order” of the nodes surrounding. Assume that each sensor can know its position, and the positioning algorithm has been adopted. Using a neural network algorithm can solve the nodal redistribution problem of WSN according to the detected region changes. In the artificial neural network, the learning algorithm can be divided into erection and growth structure learning algorithm. Growth learning algorithm starts training from a small network structure, then gradually increases until it achieves the final request. We choose the GNG algorithm, and the improved GNG-U algorithm which is improved on the basis of the GNG algorithm. To the nonstationary input signal, if the distribution suddenly changes, using the algorithm can quickly delete unused nodes, effect nodes will unite together fast, and redistribution, reduce redundant nodes finally reach optimal coverage rapidly. Combine the improved GNG-U algorithm with wireless sensor network, the network can rapidly re-coverage the target region especially for special environments. The simulation results show that, compared with the growing neural gas algorithm, the GNG-U and improve GNG-U algorithm can reduce redundant nodes, improve mobility of the network, accelerate the rate of convergence, and arrive at the optimal re-coverage dynamically.
A Markov Prediction Model Based on Page Hierarchical Clustering
Authors: Yao Yao , Shi Lei , Wang Zhanhong 
Published: January 2009

The Markov prediction model is the basis of Web prefetching and personalized recommendation. It can be used to extract connotative Web link hierarchy. The visualized site structure can not only help users understand the relationships between the pages they have visited, but also suggest where they can go next. But the existence of a large amount of Web objects results in data redundancy and model hugeness. Therefore, how to mine and improve the link structure of a website has become a chief problem and it has positive meanings for prefetching. This paper presents an improved method that simplifies the topology structure of a website and extracted the conceptual link hierarchy which can make the organization clearly and legibly. First, the Markov Tree is constructed for the reason that a more capable mechanism for representing past activity in a form usable for prediction is a Markov Tree. In this case the Markov chain model can be defined as a three-tuple (A, S, P), where A is the collection of operation, S is the state space consisting of all the states in a link structure, and P is the one-step transition probability matrix. The transition probability matrix is calculated based on the Markov tree. Second, an algorithm is given to extract the hierarchical tree from the above matrix. The website link hierarchy (WLH) is obtained accordingly. A WLH only contains a trunk link which is a hyperlink from a page on a higher conceptual level to a page on its adjacent lower conceptual level. With the levels increment, there must be more and more pages in each level. It may blur the structure of the website. In order to tackle the problem, a clustering algorithm is proposed to cluster conceptually-related pages on same levels based on their in-link and out-link similarities, which are measured by the concept of weighted Euclidean distance. After the pages in WLH have been clustered, WLC can be constructed. Finally, the simplified model will be used for Web page prediction. Three parameters, i.e. precision, recall, and PRS have been employed to measure the performance in the experiments. Experiments based on two real Web log data demonstrate the efficiency of the proposed method, which can not only have good overall performance and clustering effect but also keep the relative higher prediction accuracy and recall.
Performance Analysis for Large-Scale Parallel Microscopic Traffic Simulation System
Authors: Fei Yin , Dongliang Zhang 
Published: January 2009

PMTS (Parallel Microscopic Traffic Simulation) is a large-scale microscopic traffic network simulation system using a real traffic network of Shanghai, China. It describes traffic events in object oriented mode, uses MPI (Message Passing Interface) as communicate middleware, partitions the simulation traffic network into subnetworks, and runs simulations of subnetworks concurrently on a cluster of processors connected by high-speed Ethernet. To optimize the performance of PMTS, a number of challenges need to be solved, including traffic network partition, subnetworks communication and synchronization, and workload balance. The parallelization of PMTS is domain decomposition, which means that the geographical region for simulation is decomposed into several domains of similar size and each processor of the PC cluster is responsible for a different geographical area. The partition method needs to fulfill two conditions to make it efficient: minimize the communication overhead and partition the subnetworks of the equal computation load. The goals of maximizing the parallelization and minimizing the communication overhead is conflict, and the tradeoff should be made. PVTM simulates the vehicles activities on the traffic network, and the computation overhead for one vehicle is certain. The time overhead on one processor depends on the number of vehicles for simulation. The individual simulation of vehicle activity includes: vehicle generation, vehicle running, and the vehicle going through the boundary zone. The derivation of the predictive performance is demonstrated and the calculation of the time cost for one processor with a certain number of vehicles is provided. In order to be efficient, the load on different processors should be as similar as possible. The load depends on the actual vehicle number on the respective processor that also varies as the simulation run. In each time step, the workload is collected for each processor. For the next iteration, the information will be fed back to the load-balancer, which will move the boundary of the grid to balance the vehicle numbers among the domains. The performance metrics of the simulation system mainly depend on the load balance, scalability, speedup, and efficiency. The performance optimization of PMTS has been proved to be effective when it is put into use and the experiment results are also provided which match the analysis.