Abstract:The wireless sensor network,which has a range of application values,is the important carrier for the Internet of Things and the key technology extending the covering area of Internet in the future.Due to the variability of communications environment and the diversity of communications service,topology control based on the information of monolayer faces a new challenge.This paper utilizes the game theory to involve the expected node degree,the connected factor and the Interference node numbers of MAC layer into the revenue function,which also constructs the game model of topology control.Next,the paper proves the existence of Nash equilibrium and proposes an energy-balanced and reliable topology control game algorithm(EBRGA)for sensor networks. Theoretic analysis and simulations validate that it could ensure networks good characteristics of connectivity,high reliability,fast convergence and energy equilibrium etc.

Abstract:Wireless sensor network(WSN)can effectively perceive,collect,and process the data in the monitored area.It provides an approach for human to get information.In the field of WSN,the query and storage of data is very important.It mainly used to solve how to effectively manage the distributed data in the monitored area with extremely limited resources.Recent advances in technology have made the number of sensor of the sensing model developed from single sensor to multiple sensors.The existing storage scheme for one-dimensional is not suitable for the multi-dimensional data or when it used it costs too much energy.Meanwhile the scheme has a certain degree of robustness to packet loss and node failure.Finally,the study has created experiments on the platform of Matlab and the results have shown that it has some advantages compared with the existing methods.

Abstract:In wireless ad-hoc and sensor networks,localization is often viewed as one of the most significant problems.This study has designed a localization system that abstracts the distance of every neighbor nodes pair as the length of a spring between them and then attains the final position information through spring updating. Compared with other spring-based localization methods,this system converges faster because it uses a displacement vector that has proven to be more efficient in updating coordinates.The system performs better than range-free localization methods even under high ranging error.

Abstract:Wireless sensor networks are widely used to monitor various kinds of events that happened in the sensing area.On the contrary,in order to avoid being detected,intelligent mobile targets are exerting themselves to seek paths with the least exposure passing the sensing area.Looking at the issue of intelligent moving targets seeking the appropriate moving path,the study analyzed the defects of existing moving path algorithms and proposed the AFMP(Angle First Moving Path)algorithm that generates a moving path via choosing the appropriate direction.Theoretical analysis and simulation results illustrate that the AFMP algorithm does not require global node information and isomorphic sensing radius of nodes.Also,it has a lower sensitivity when compared to the node deployment density and distribution.Therefore,the algorithm is especially suitable for the case when only local node information is known.Moreover,the complexity of the algorithm is lower than that of the Voronoi algorithm and the ideal grid algorithm.

Abstract:A mechanism based on target assistance is proposed in this paper.This mechanism is mainly divided into two forms:static target assistance based self-localization mechanism and mobile target assistance based self-localization mechanism.The former,according to the measured DOA by nodes,first beacons through the pseudo-linear least square method to locate the static targets.Next,the unknown nodes are located by previously located static targets through BML.For the latter,BML,PCML and RML three algorithms are adopted in the self-localization and have been compared among themselves.From the MATLAB simulation results,the increasing the number of static targets contributes to an improvement of accuracy.PCML and RML can compensate the delay of sound propogation and increase the accuracy of localization when the target with a high speed.Finally,the feasibility of this mechanism is validated by experimental datas.

Abstract:In vehicular delay tolerant network(VDTN),vehicles nodes often move frequently,which results in existing no end-to-end communication path between any nodes at a given moment,and VDTN has intermittently connectivity.The clock oscillators in the vehicle nodes are also susceptible to environment factors,and the crystal frequency fluctuates in the state of irregular.There exits much limitation and difficulty,when the traditional network clock synchronization algorithms are introduced directly into VDTN.A two-dimensional clock synchronization algorithm for vehicular delay tolerant network is proposed,which includes two synchronization processes in the vertical dimension and in the horizontal dimension.The two-dimensional clock synchronization algorithm reduces the time synchronization error and improves the synchronization accuracy,compared with the one-way synchronization.The experimental results show that VDTN obtains a higher synchronization accuracy through the two-dimensional clock synchronization algorithm.

Abstract:With the aim of resolving the problem that sensors use asynchronous sleep-wake scheduling to increase the communication delay,this paper proposes a regulating duty-cycle mechanism based on the excellence of parallel of Dual-Radio.This mechanism makes the wake-up time of node earlier by regulating the duty-cycle of nodes dynamically,and predicts the conflict on the data transmission to reduce the interference of conflict.Simulation experimental results and theoretical analysis show that solution uses less energy and reduces the communication delay.

Abstract:In wireless sensor networks,RSSI is considered as an appealing modality for localization in WSN as RSSI information can be obtained at almost no additional cost.To effectively utilize RSSI for localization,two directions have been investigated:RSSI fitting and RSSI profiling.Many state-of-art localization algorithms—falling in these two categories,however,work poorly in real environments because of imprecise mapping relationship between RSSI and the physical distance due to the impact from multi-path,environment noisy,et al. This paper proposes an Omni-Fitting RSSI Map Based Self-Localization Algorithm(ORM).In ORM,the study samples limited RSSI values in several different directions and distances in advance.Based on this information,the study can endue the global radio strength distribution map of the positioning area.According to this map,the unknown nodes can conduct localization to acquire their coordinates.ORM considers the anisotropic characteristics of radio transmission model carefully which makes it own the advantages of both good scalability and acceptable precision.In order to demonstrate the performance of the approach,the study builds up a testbed with 14 MICAz motes to run ORM.The results show that this method can outperform W-Centroid algorithm by about 26% in indoor environment and as much as 42% under outdoor circumstance.

Abstract:The high mobility of vehicles causes the frequent change of networks topology.This is part of a huge huge challenge on the data dissemination of VANETs.Even though existing flood-based routing protocols provide high reliability,they can not achieve the good trade-off shown among delivery ratio,delay,and the number of message redundant copies.A data dissemination scheme based on adaptive node density for VANETs is proposed. Nodes can rapidly gain the geographical distribution of“hotspot”regions via the proposed distributed algorithm. The hop-count limit function is established which is based on the Euclidean distance of the nearest“hostspot” region and density of nodes.When making forwarding deciding,nodes set a dynamically upper bound on the message hop count to avoiding unnecessary message redundant copies in the“hotspot”region.The number of message redundant copies can be effectively reduced in the network.The simulation results show that the delivery ratio and delay of this scheme are close to the epidemic routing protocol,but the number of message copies can be reduced by 37.5%.

Abstract:Enabling anytime and anywhere random data access for the mobile sinks is an important solution to the problem in the large scale wireless sensor networks.However,the data discovery in large scale sensor networks faces a non-trivial challenge because of the double blindness between the data and the sinks.The existing schemes are not able to provide the high success rate and consume less energy at the same time.In this paper,the tradeoff between randomness and structure is explored.Based on random line walk scheme,three scalable and efficient data discovery methods are presented to solve the double-blindness.These methods utilize simple geometric property to construct the path of data cache and query and can work well without location.The extensive simulations,using ns-2 and theoretical analysis,have proven the efficient trade off between randomness and structure.

Abstract:Location is of great importance wireless sensor network applications because location information can often be used to identify events.TODA is a typical localization scheme widely used in previous work,but it requires time synchronization over all anchor nodes with known positions.Time synchronization increases the cost and complexity of system,and the errors caused by software and hardware seem subtle but often lead to bad accuracy of localization.A new TDOA localization scheme is presented in this paper,whose basic idea is to use an additional, position-known signal source,S′to change the way of calculating TODA values.After the emission of the source signal S,the new signal S′is emitted.The TDOA of S between different receivers can be derived from the time difference of receiving S and S′,called TD2S,at each receiver.This way eliminates the dependence of TODA on time synchronization,and improves the localization accuracy.Experiments under three-dimensional space have been conducted with mobile phones,and the results show that the proposed scheme is not only of high accuracy,but also of easy deployment,low cost,and robustness.

Abstract:There are shortcomings in traditional anti-theft technology which can not satisfy a user’s demand.The common ways of anti-theft are limited in wireless sensor networks.On the topic of the shadowing effect in wireless communication,this paper introduces a anti-theft technology based on wireless sensor networks.System can check intrusion by analyzing received signal strengths.This paper establishes a framework of anti-theft system and studies the key technologies.By defining the graph model in anti-theft system,the agent distribution problem is abstracted into edges partitioned by vertices problem.B-EPV algorithm is proposed for obtaining the optimal solution.Blade algorithm is designed for solving k-mode set problem to get steady status of link.This paper constructs experimental environment with real motes and verifies the performance of the system.The result shows low false positives and false negatives in the system.

Abstract:This paper studies the cooperative routing algorithm for maximizing the network lifetime in sensor networks.The study assumes nodes in the network are able to perform cooperative transmission to achieve transmit diversity,and proposes a joint cooperative transmission and energy conserving routing algorithm to prolong the network lifetime.First,a lifetime maximization problem via cooperative nodes is considered and performance analysis for MPSK modulation is provided.With an objective to maximize the minimum device lifetime under a constraint on bit-error-rate performance,the optimization problem determines which nodes should cooperate and how much power should be allocated for cooperation.Since the formulated problem is NP hard,a distributed suboptimal algorithm is developed for multi-node scenarios.The study demonstrates through simulation that the proposed solution achieves more than twice the length of the network lifetime compared with non-cooperative routing,when it is used with FA algorithms.

Abstract:Due to the instability of wireless links and the complexity of geographical environment where wireless sensor networks are deployed,sensor nodes can not guarantee communication with their neighboring nodes with high probabilities.Resolving the problem of finding the sensor nodes that communicate well in practical settings can play an important role in node clustering and the optimization of routing protocols.It is important to note the discovery which nodes in a region are more close to each other in actual movement.A new algorithm called K-CLOSE is proposed in this paper to solve the problem which finding the most k close regions.First,K-CLOSE abstracts wireless sensor networks into uncertain graphs in a distributed manner.Then,the closeness threshold is determined by an approximation algorithm proposed in this paper,which has approximate rate 2.Finally,the k close regions where sensor nodes communicate with high probabilities are discovered using tree searching and branch-and-bound methods.Moreover,the experimental results show that the proposed algorithm is efficient in practice.

Abstract:An optimal scheduling structure for data aggregation in wireless sensor networks is proposed.The paper evaluates this scheduling policy with different-weight based binary tree networks.The analysis and experiments indicate that the total delay in whole network can be efficiently decreased by using this scheduling policy,especially when the number of binary nodes in the experiment equals to 25,the result approaches the most optimal line.Unfortunately,this scheduling cannot maintain stability when network scale improves rapidly.

Abstract:When sensor networks are deployed in mission-critical applications such as target detection,data fusion technologies can significantly improve sensing coverage.Based on the probabilistic sensing model with an exponential decay factor,the paper analyzes the intrinsic relationship between data fusion and coverage performance.The paper also proposes some definitions,including node virtual radius,fusing-cover,to quantize the improvement on network coverage performance caused by data fusion.The effect of data fusion on node density, where sensor nodes are deployed virtually in the regular polygon way,is evaluated.On the base of above theoretical analysis,a virtual radius based coverage algorithm to schedule sensor nodes is designed to guarantee every interest point in the region being either covered,or fusing-covered.The theoretical analysis indicates that the number of nodes which are participated in fusion process within virtual radius must be less than six.Otherwise,data fusion does not reduce the node density,and has a negative effect on the node density.The experimental result demonstrates that the proposed method can efficiently improve the coverage performance and prolong sensor network’s lifetime.

Abstract:Due to high mobility and sparse distribution of vehicle nodes,data packets transmission in VANET face great challenges.To address the problem,this paper proposes a link-ware routing protocol named as LALO. The study first introduces a distributed beacon detection scheme to gather local traffic statistics,so vehicle nodes storing packets can predict performance matrix of transmission paths and decide which path is the optimal one to choose.Results show that the proposed LALO protocol outperforms existing solutions in terms of packet delivery ratio,protocol overhead and transmission range.

Abstract:To balance the energy consumption of nodes and maximize the lifetime of wireless sensor networks,a sleeping schedule mechanism which rotates the dominators is proposed.One abstraction considered for the sleeping schedule is the domatic partition problem,whose essence is to find some disjoint dominating sets and to achieve an energy efficient sleeping schedule by rotating them.This paper solves the 2-domatic partition problem.Based on uniform clustering,a constant-factor approximation algorithm DPUC(domatic partition by uniform clustering)is proposed for 2-domatic partition with the approximate radio of (δ+1)/4,where δ is the minimum degree of nodes. The algorithm runs in a constant-rounds time and can be extended into a k-DP approximation algorithm.Meanwhile, the algorithm solves one open problem proposed by Pemmaraju and Pirwani.That is,whether a k-DP algorithm can run in a constant-rounds time using connectivity information only.Finally,the simulations demonstrate the correctness and feasibility of the DPUC algorithm.

Abstract:Wireless reprogramming approach of sensor node is a requirement for flexible configuration and update. Considering the communication overhead and the program overhead,this paper presents a novel lightweight wireless reprogramming approach–EasiLWR with the following merits.By comparing the functions of the new program and the old program,the different codes between functions are transferred instead of entire codes.The communication overhead is reduced.Moreover,using the code shift,the parts of program,which need frequently update are stored and implemented in RAM rather than in the internal Flash of microcontroller unit(MCU).This translates to a reduced programming time.The experimental results show the outperformance of EasiLWR.

Abstract:For real-time surveillance applications based on wireless sensor networks,the requirement for real-time performance and the energy efficiency are two mutually-restricted metrics,which can be satisfied by sleep scheduling.On the other hand,controlled deployment is another method for cost and performance guarantee.This paper manages to put the two apparently independent issues into a simultaneous optimization framework and make tradeoffs among the deployment cost,the network lifetime and the real-time performance.This paper proposes a simultaneous deployment and scheduling strategy based on NSGA-Ⅱ and obtains Pareto solutions which satisfy multiple metrics.It also analyzes extensively the impact of sensor’s duty-cycle factor,the delay constraints and the sensor’s sleep mode on deploying and scheduling a performance.