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Showing papers in "Journal of Nanjing University of Posts and Telecommunications in 2009"


Journal Article
TL;DR: This paper discusses the relations between Next Generation Network, Cyber-Physical Systems, Wireless Sensor Network and the IOT, and proposes service types and node classification of IOT and designs the architecture and system model of Iot based on passive, active and internet nodes structure.
Abstract: The technology of the Internet of Things (IOT) has attracted highly attention of academia,industry,and news media.There are still many open issues in the definition,internal principles,architectures and system models of IOT.Through the analysis of current technical materials and application cases of IOT,this paper discusses the relations between Next Generation Network,Cyber-Physical Systems,Wireless Sensor Network and the IOT.It proposes service types and node classification of IOT and designs the architecture and system model of IOT based on passive,active and internet nodes structure of IOT.After summary of the features of IOT,it proposes the suggestions on the researches and development of IOT.

49 citations


Journal Article
TL;DR: Simulation results show that DCS can achieve acceptable estimation accuracy in an energy efficient way and the analysis of relationship between reconstruction error and compression ratio in DCS and Energy efficient performance of DCS is carried out.
Abstract: In this paper,spatial correlation-based Distributed Compressed Sensing (DCS) model and algorithm was presented in Wireless Sensor Networks (WSN),where spatial correlation and joint sparse models between the sensor nodes can be exploited in order to compress and reconstruct sensor observations in an energy efficient manner based on coding/decoding algorithm of DCSFinally,the analysis of relationship between reconstruction error and compression ratio in DCS and Energy efficient performance of DCS are carried out in simulationSimulation results show that DCS can achieve acceptable estimation accuracy in an energy efficient way

11 citations


Journal Article
TL;DR: In this article, a soft threshold function is used to process modulus maximum array and the signal after de-noising becomes more smooth, which can improve the phenomenon of thorn and oscillation effectively.
Abstract: Although traditional processing method of modulus maximum array can retain characteristics of signal,the signal after de-noising exists thorns and slight oscillation at singularity point.The improved method is that soft threshold is used to process modulus maximum array.Because the soft threshold function is continuous,the signal after de-noising becomes more smooth.The MATLAB simulation results confirm that the improved method can improve the phenomenon of thorn and oscillation effectively.

7 citations


Journal Article
TL;DR: The traffic detection system is introduced, and it is pointed out that the video based traffic detection technique is increasingly becoming the most active research topics in the field of computer vision.
Abstract: The traffic detection system is introduced first,and it is pointed out that the video based traffic detection technique is increasingly becoming the most active research topics in the field of computer vision.Then various algorithms are discussed respectively,such as the commonly used vehicle detection algorithms,the model based vehicle detection algorithms,the basic types of vehicle tracking,as well as the template matching,Kalman filtering and Particle filtering based vehicle tracking algorithms.The advantages and disadvantages of various algorithms are compared in detail.Finally,the hot spots for future research in this area are presented.

7 citations


Journal Article
TL;DR: It is shown by Matlab simulations that the proposed algorithm greatly enhances the security of image encryption without image distortion comparing with the traditional Logistic chaotic encryption algorithm.
Abstract: Logistic map is a simple non-linear model,but it has complex dynamicsThis paper analyzes Logistic chaotic image encryption algorithm,and proposes an improved encryption and decryption model based on the algorithmIt is shown by Matlab simulations that the proposed algorithm greatly enhances the security of image encryption without image distortion comparing with the traditional Logistic chaotic encryption algorithm

4 citations


Journal Article
TL;DR: The practical instance analysis and comparison of uncertain context reasoning in the intelligent space scene indicates that the concept is clear and the computing is concise, and proves the preferable practicability and perfect reliability of the approach.
Abstract: In the applications of context awareness computing,it is required that the reasoning and fusion of original context data must be executed to obtain higher level context information.A new uncertainty reasoning approach is presented by way of the cosine of identical discrepant contrary vector angle based on set pair analysis(SPA).The practical instance analysis and comparison of uncertain context reasoning in the intelligent space scene indicates that the concept is clear and the computing is concise.It also proves the preferable practicability and perfect reliability of the approach.

2 citations


Journal Article
TL;DR: The experiments indicate that the trust model that the bid and trust renewal improved improved are introduced in grid not only mobilizes the enthusiasm of the resource entities, carries out the interaction of the users and the resources, and raises the efficiency of the research, but also do better in preventing of bad recommendations.
Abstract: In order to raise the efficiency of the research and prevent of bad recommendation,the bid and trust renewal improved are introduced into a trust mode in grid in this paper.The valuators send the bid information to the resources entities,whether the resources entities bid according to the bid information,if the valuators receive bid applications sent by the resources entities,than they just only research trusted entities in the resources entities that they have send the bid applications,than the valuators sign the contract with the resources entities which accord with the conditions.The total trust value is used to be the quite real trust value after recommendations in the trust renewal,it will be compared with recommendation trust value,and the feedback will be made by the distance between them,than the trust value of the entity will be adjusted according the feedback.The experiments indicate that the trust model that the bid and trust renewal improved are introduced in,not only mobilizes the enthusiasm of the resource entities,carries out the interaction of the users and the resources,raises the efficiency of the research,but also do better in preventing of bad recommendations.

2 citations


Journal Article
TL;DR: Simulation results show that the largest posterior probability?rule and Bayesian rule can approach ascendant sensing performances in the CR networks.
Abstract: Cooperative spectrum sensing enables a Cognitive Radio(CR) networks to reliably detect primary users and avoid causing interference to primary user's communications.The data fusion technique is a key component of cooperative spectrum sensing.Four data fusion methods have been investigated in this paper,including "AND" rule,"OR" rule,the largest posterior probability?rule and Bayesian rule.We use them to sense spectrum cooperatively in CR networks and their spectrum detection performances were compared.Simulation results show that the largest posterior probability?rule and Bayesian rule can approach ascendant sensing performances in the CR networks.

2 citations


Journal Article
TL;DR: The background is firstly modeled using adaptive Gaussian mixture models in YCbCr color space, and the foreground regions including moving objects and cast shadow are extracted from current frame by comparing the each pixel with Gaussian model.
Abstract: Gaussians mixture model (GMM) has been widely used for moving object detection based on background modeling.In this paper,the background is firstly modeled using adaptive Gaussian mixture models in YCbCr color space,and the foreground regions including moving objects and cast shadow are extracted from current frame by comparing the each pixel with Gaussian model.Then,the texture of little patches is represented by local binary patterns and the cast shadow is detected and eliminated based on the texture similarity between shadow region and corresponding region in the background.Finally,the geometric features of cast shadow are imposed to further improve the performance of moving object detection.Experimental results demonstrate the proposed algorithm can effectively detect cast shadow and moving object,and has higher practicability.

2 citations


Journal Article
TL;DR: The RSSI-based distance estimated model is studied, a parameter calibration method is provided which in specific to indoor environmental applications performs well in distance estimate accuracy and experience on the prototype node—Ubicell shows that the proposed calibration method performs well.
Abstract: Localization is one of the basic services for data collection in wireless sensor networks.The localization accuracy to some extent depends on the accuracy of distance estimation.The advantage of employing the RSSI( Received signal strength indications)-based distance estimation have some metric that no extra hardware and fewer communication cost and lower implementation complex which can adapt to energy-limit wireless sensor network.In this paper,we studied and analyzed RSSI-based distance estimated model,and provide a parameter calibration method which in specific to indoor environmental applications.Experience on our prototype node—Ubicell and shows that the proposed calibration method performs well in distance estimate accuracy.

2 citations


Journal Article
TL;DR: An analysis and simulation to the protocol improved fore-and-aft showed that the optimized protocol didn't increase the complexity apparently when reduced the end-to-end delay and packet-loss-rate, and thereby improved the performance of networks.
Abstract: Based on a widely used congestion control mechanism——Random Early Detection(RED),a method was proposed to improve the AODV routing protocol: during the route found period,an intermediate node behaved in different ways according to its average queue length when received a RREQ.Thereby,the new route was more stable and data flow would bypass heavy-burden-nodes,which realized congestion control and flow balance to some extent.Finally,made an analysis and simulation to the protocol improved fore-and-aft,the result imitate that the optimized protocol didn't increase the complexity apparently when reduced the end-to-end delay and packet-loss-rate,and thereby improved the performance of networks.

Journal Article
TL;DR: A dual mode CMA algorithm MCADAMA, modified CMA-assisted decision adjusted modulus algorithm, suitable for QAM signal is proposed, which has faster convergence rate and lower bit error rate and can improve system performance effectively.
Abstract: We proposed a dual mode CMA algorithm MCADAMA(modified CMA-assisted decision adjusted modulus algorithm),which is suitable for QAM signal.Inspired by the MCMA,based on the study of dual-mode CMA algorithm CADAMA proposed by Axford,we proposed and studied the MCADAMA algorithm and compared MCADAMA with other three CMA algorithms based on a blind equalization system of QAM.The simulation results showed that the MCADAMA has faster convergence rate and lower bit error rate,and can improve system performance effectively.

Journal Article
TL;DR: The QoS provisioning techniques in the lowest three protocol layers of wireless mesh networks and the cross-layer design techniques are classified, and their research developments are systematically introduced.
Abstract: First,the basic situation of wireless mesh networks was briefly reviewed,and the necessity and significance of providing QoS guarantees for such networks were analyzed.Then,we classified the QoS provisioning techniques in the lowest three protocol layers(i.e.physical layer,MAC layer and routing layer) of wireless mesh networks and the cross-layer design techniques,and systematically introduced their research developments.Finally,some problems and research directions of these QoS provisioning techniques were given.

Journal Article
TL;DR: A mechanism to detect network attack, based on the combination of the network environment information auto-apperceiving technology and the intrusion detection technology, and a mechanism of network flow transparent redirection based on OpenVPN and strategy routing are proposed.
Abstract: Network attack flow redirection is a key technology in honeyfarm,this paper focuses on the research of its mechanism.We propose a mechanism to detect network attack,based on the combination of the network environment information auto-apperceiving technology and the intrusion detection technology,and present annother mechanism of network flow transparent redirection based on OpenVPN and strategy routing.Moreover,a network attack flow redirection system based on the proposed mechanism is accomplished.Finally,some experiments are performed and the results verify the effectiveness of the system.

Journal Article
TL;DR: A design scheme of using MPC8270 embedded processor and embedded Linux operating system to composite the network communication server to achieve at IP network communication on E1 transmission network is proposed.
Abstract: In this paper,a design scheme of using MPC8270 embedded processor and embedded Linux operating system to composite the network communication server to achieve at IP network communication on E1 transmission network is proposed.Focused on discussing one of the keys to implement the scheme,which is the design of E1 network driver.The design method of the driver for realizing the E1 network communication under HDLC communication mode based on the MPC8270 FCC Communication Controller is given.The network communication server with E1 network driver has been applied in real communication systems.

Journal Article
TL;DR: Wang et al. as mentioned in this paper analyzed the status, significance and problems of developing digital trunking communication in Jiangsu province, and certain countermeasures are put forward in the end.
Abstract: Efficient emergency communication is a reliable safeguard for government to deal with emergencies,and digital trunking communication is an efficient way of private mobile communication.Beginning with the introduction of trunking communication system,this paper analyzes the status,significances and problems of developing digital trunking communication in Jiangsu province,and certain countermeasures are put forward in the end as follows: the strategic status of the development in digital trunking communication industry should be emphasized;financial and political support should be provided by government;appropriate system should be chosen for the construction of digital trunking emergency communication;sufficient market research and program of digital trunking communication network must be carried out;the cooperation of public network,private network and shared network should be well managed.

Journal Article
You Xiaohu1
TL;DR: A cross-layer optimization approach to the spectrum sharing in cognitive radio based Ad Hoc network is proposed with the objective of minimizing the total BFP (bandwidth-footprint product).
Abstract: A cross-layer optimization approach to the spectrum sharing in cognitive radio based Ad Hoc network is proposed.Jointly considering interference constraints among cognitive radio users and rate demand,especially considering bi-directional links and the channel heterogeneity,the optimization problem is formulated in the form of binary integer linear programming(BILP)with the objective of minimizing the total BFP(bandwidth-footprint product),and the optimal spectrum sharing and routing is presented.

Journal Article
TL;DR: In this article, a dual mode bandstop filter is presented, which consists of a symmetrical dual mode square ring resonator and a coupled transmission line with quarter-wave length.
Abstract: In this paper,a dual mode bandstop filter is presented,which consists of a symmetrical dual mode square ring resonator and a coupled transmission line with quarter-wave lengthBy adding two small patches in the opposite edges of the ring resonator,the mode perturbation can be realized,thus resonant frequencies of the degenerate modes can be separated to build the working stop bandMeanwhile,the quarter-wavelength line is used as the impedance inverter between the input and output,and the gap between the resonator and the inverter is used as the feeding structureFilter samples are fabricated and measured and the experimental data validates this design well

Journal Article
TL;DR: An improved scheme based on irrational numbers is proposed, which can obtain the same key space with AES algorithm by spending the same running time with DES algorithm.
Abstract: DES and AES method for data encryption are discussed in this paper,and the analysis of security is also given,then an improved scheme based on irrational numbers is proposed.The encryption algorithm,which takes advantage of pseudo-chaos characteristics of irrational numbers,can expand key space,enhance the randomness of sub-keys and use different sub-keys in each group of 16 rounds.Therefore,the proposed scheme can obtain the same key space with AES algorithm by spending the same running time with DES algorithm.

Journal Article
TL;DR: Based on wavelet packet transform(WPT) layered technique and independent sub-band functions, a new signal processing technique to accomplish blind source separation in a single-channel mixture signal is presented.
Abstract: Based on wavelet packet transform(WPT) layered technique and independent sub-band functions,the paper presents a new signal processing technique to accomplish blind source separation in a single-channel mixture signalFirst,we discuss the single-channel mixed-signal separation model,as well as how to carry on the Layered using WPT,and how to gain the technique of the independent sub-band functionsThen,combining independent sub-wave function into the one-way mixed-signal,one-way mixed-signal conversion can become multi-dimensional vector from one-dimensional vector,in order to achieve its blind source separationFinally,the separation experiment of heart sounds signal,verifies the efectiveness and feasibility of the propsed method

Journal Article
TL;DR: The proposed LEACH-P protocol makes use of cooperation of the nodes in the phase of cluster head election to collect global information and economizes energies of nodes and extends the network life cycle compared with LEACH.
Abstract: In traditional LEACH protocol,dynamic cluster head election algorithm was used in the phase of cluster head election.The number of cluster heads elected in every round is not optimal due to the irrational probability for every node elected itself to be cluster-head.The deviation among the numbers of cluster head in each round was much more bigger,this can not optimize the energy consume of sensor nodes.This paper proposes the LEACH-P protocol to resolve this problem.It makes use of cooperation of the nodes in the phase of cluster head election to collect global information,this information can eliminates the robust of the election algorithm of LEACH and enhances the cluster head election algorithm accordingly.The simulation result shows that LEACH-P economizes energies of nodes and extends the network life cycle compared with LEACH.

Journal Article
TL;DR: An selective maximum multi-user diversity(SMUD)scheduling scheme which can reduce feedback load while preserve most of the capacity performance in MIMO Channels is proposed in this paper.
Abstract: An selective maximum multi-user diversity(SMUD)scheduling scheme which can reduce feedback load while preserve most of the capacity performance in MIMO Channels is proposed in this paper.Each user compares its maximum SINR to a threshold only those who fall above it along with the index transmit antenna are sent back to the base station.The base Station allocates independent channels to the users with the highest SINR.Average capacity and feedback load for the proposed method is obtained and shown to match the simulation very well.

Journal Article
TL;DR: In this article, the authors divide a time series into several subsequence, by the periodogram, they give an estimator of the spectral density, based on this they use the 3σ principle and two-factor analysis of variance to compare each subsequence to test for stationary of mean and covariance separately.
Abstract: We divide a time series into several subsequence,by the periodogram we give an estimator of the spectral density.Based on this we use the 3σ principle and two-factor analysis of variance to compare each subsequence to test for stationary of mean and covariance separately.Comparing to other methods,this method can help us to avoid complex compatation and give the statistics with the testing principle to avoid the subjective affect.

Journal Article
TL;DR: An adaptive routing algorithm based on the security mobile agent is proposed, in which mobile agents migrate in the net to get the network state and update the route table, which builds a communication-trust table in every network node.
Abstract: Mobile agents travel and collect information in the network.Because of the openness of the network,the security of agents and data inside are badly threatened.This paper proposes an adaptive routing algorithm based on the security mobile agent,in which mobile agents migrate in the net to get the network state and update the route table.It also builds a communication-trust table in every network node,using virtual space to ensure the agents' safety.A simple network model is also built on the Grasshopper platform to apply the algorithm.

Journal Article
Zheng Xin1
TL;DR: In this article, a case study of the discussion of users of the lily BBS of Nanjing University on the topic of Extension Project of Hankou Road was conducted, and the authors found that the collective behavior in the Internet showed much irrationality at the beginning of the case and rational ideas were mostly in the shadow.
Abstract: This article takes the discussion of users of the lily BBS of Nanjing University on the topic of Extension Project of Hankou Road for a case study.Through the analysis of the questionnaires and observations of the web discussion,we found that the collective behavior in the Internet showed much irrationality at the beginning of the case.The irrationality took a dominant role in the discussion while rational ideas were mostly in the shadow.However,with the development of the actual case and the deepening of the discussion,objective and rational views gradually took the lead and returned to the mainstream after battling with the irrational ones.Finally,the article gives some thoughts to the return of rational views: is it a true return in some sense? Will it bring another climax of the discussion if one thing associated with this event takes place? In what direction will the discussion evolve?

Journal Article
TL;DR: Based on this trust model, the dynamic evaluation method to the visit model of the Grid system security, and the proof of the possible rationality of this practice is given.
Abstract: The Grid security issue is the core problem and difficulty of the Grid research.This paper attempts to develop a trust evaluation mechanism to measure the Grid system visit credibility.Based on this trust model,it describes the dynamic evaluation method to the visit model of the Grid system security,and gives the proof of the possible rationality of this practice.

Journal Article
Wang Hui1
TL;DR: This work improves the Xavier IBES scheme, and uses the secret sharing scheme of threshold cryptography to split the master secret s among n peer to peer third PKGs.
Abstract: In order to improve the confidentiality of the private key generator(PKG)in identity-based encryption-signature(IBES)scheme,we improve the Xavier IBES scheme,and use(t,n)secret sharing scheme of threshold cryptography to split the master secret s among n peer to peer third PKGsWe apply the new IBES scheme in wireless sensor network,and discuss its efficiency and security in terms of complexity,storage requirement and securityAnalysis shows that our scheme can efficiently improve the confidentiality of the PKG and the security of wireless sensor network

Journal Article
TL;DR: Methods of DIP (digital image processing) to measure geometric parameters of optical fiber automatically is studied and this measure method has characters such as quick measurement, high precision, and easy to operate.
Abstract: In this paper,using methods of DIP(digital image processing) to measure geometric parameters of optical fiber automatically is studied.This measure method has characters such as quick measurement,high precision,and easy to operate.DIP methods are used to analyze and process various fibers end face images.The relevant mathematical models are established to calculate geometric parameters of various fibers.Software system with sufficient functions is designed with matlab7.0.

Journal Article
TL;DR: In this article, a novel force sensor based on optical beam deflection was developed to investigate the mechanical effects of iron sheet during cavitation bubble collapse near solid boundary in water, and the acoustic transient radiated by bubble collapsing is also studied experimentally by PZT hydrophone.
Abstract: A novel force sensor based on optical beam deflection was developed to investigate the mechanical effects of iron sheet during cavitation bubble collapse near solid boundary in water.The acoustic transient radiated by bubble collapsing is also studied experimentally by PZT hydrophone.The effects of the bubble energy, as well as the dimensionless parameter γ(γ=L/Rmax),RBmaxB is the maximum bubble radius and L is the distance of a cavity inception from a boundary) on the acoustic radiation during cavitation bubble collapsing near solid wall are analyzed.The experimental results are shown that the target is impacted in turn by laser-generated ablation force and high-speed liquid-jet impulse induced by bubble collapses.The liquid-jet formation appears earlier than the acoustic transient.Furthermore,the percentage of bubble energy turning into the acoustic transient energy increases with the oscillation.Compared the amplitudes of the second liquid-jet with the amplitude of the acoustic transient during the second duration,we deduce that the acoustic transient radiated by cavitaion bubble is the main attenuation mode.The results are of values in theoretical and applied research in the laser-matter interaction water.

Journal Article
TL;DR: For the abnormal process behaviors got in digital forensic process, the paper gives a method of reconstructing the crime process with the process events and validates the feasibility and effectiveness of the method with the developed simulation software.
Abstract: For the abnormal process behaviors got in digital forensic process,the paper gives a method of reconstructing the crime process with the process events.In the method,it firstly formally describes dangerous process operations and process communications by CSP theory,and builds a communication state model of process using the process records in system to get the process communication rules,then finds the communication sequence which can form reasonable evidence link after analyzing all possible communication sequences in the model with interpretation algorithm based on path search and excluding communication sequences out of rules.In the last,the paper gives a specific analysis and explanation of process behaviors by formalizing evidences and constructing CSP model,and validates the feasibility and effectiveness of the method with the developed simulation software.