最新刊期

摘要：Multicast is the fundamental communication mechanism for all sorts of group oriented application sush as video conference or cooperative work.It is important to study and improve the security of multicast.As multicast is layered on top of unreliable communication protocols such as UDP in TCP/IP protocol suites,data packets are lost possibly.Most multicast authentication schemes do not tolerate packets loss,some others may only work in random packets loss while vulnerable to active attack.In this paper,a new concept of partial collision resistant hash function is introduced,base on which,together with hash graph and error correcting code,an efficient multicast authentication scheme over lossy channel is presented.The scheme is not only very efficient in computation and communication complexity,but also secure against active attack.After a formal security modeling of multicast authentication schemes over lossy channel,the security of the proposed scheme is proved under this definition.  

摘要：Concerning the problem of decrease in Wireless Mesh Network(WMN)throughput caused by channel interference,this paper proposes a new multi-channel allocation strategy based on the interference model.This strategy first stratifies WMN and then allocates channels according to the priority of layers.By alleviating channel interference of the network,it promotes each node’s throughput in WMN and thus to increase the network throughput.The simulation results show that the strategy is efficient.  

摘要：The routing optimization problem existed in nested mobile network based on Mobile IPv6 is introduced by the traditional Internet architecture in essence,where the IP address functions as locator as well as identifier.In this paper,a new Internet architecture based on identifier/locator split is proposed.In this new architecture,the IP address functions only as locator while endpoint identifier is introduced to function as transport identifier.In addition,a route optimization mechanism for nested mobile network based on the identifier/locator split architecture is proposed.The mechanism introduces route update option,route acknowledgement option,and route delete option,which are encapsulated in IPv6 hop-by-hop extended header,to perform the route optimization.The analytical results show that the new mechanism has lower packet overhead and routing update delay than traditional mechanism.  

摘要：Communication and direction-finding play important roles in modern electronic systems.In order to design transmit sources for integrated systems of communication and direction-finding,we propose a new space modulation OFDM technique,with which the system can transmit microwave signal carrying 2-dimensional directional information.The main idea is that the eight element antennas spaced in more than half wavelength are divided into four arrays to produce multi-beams,so that the received OFDM signal has been modulated by azimuth angle and elevation angle.The single-antenna receiver could accomplish communication and direction-finding by demodulating signals in the beam-space.This paper presents how to choose the signal constellations of space-time modulation ,how to design the scheme of the differential coding,and how to develop the algorithm of demodulating and estimating directional information.The performances of bit error rate and direction-finding in Gaussian channel are investigated.Simulation results show that the design of system is successful.  

摘要：Based on the configuration of spaceborne distributed InSAR system,the height measurement error sources including satellite attitude error,interferometric baseline error,interferometric phase error,time,frequency and beam synchronization error and slant range measurement error are analyzed.The error transfer relationship of distributed InSAR system is presented.Emphasizing on the synchronization error,the error transfer model from all kinds of error sources to height measurement error is deduced.The theoretic performance evaluation method of the distributed InSAR system is presented.Based on the simulating system which containing full process of the distributed InSAR system,a novel system simulation method is proposed by constructing a typical scene or nature scene with determinate average slope.Combining the theoretic and simulation experimental performance evaluation methods,the performance evaluation result of the distributed InSAR system will more comprehensive and believable.  

摘要：This paper presents the model of satellite planar array multi-beam antenna and the concepts of beam-space and element-space.The adaptive nulling and interference localization based on beam-space of satellite planar array multi-beam antenna are investigated and some simulation results are also presented.Theoretic analysis and simulation results show that the adaptive nulling and interference localization based on beam-space of satellite planar array multi-beam antenna can be applied to satellite communication systems and it can increase the anti-jamming ability of satellite communication systems sharply.  

摘要：A reconfigurable optical network test-bed driven by dynamic traffic is designed,integrated and demonstrated.Permanent connection and switched connection is established.A realizing technique of the full fit scheme in reconfigurable grooming of dynamic traffic is discussed and a kind of the network which structure can be automatically reconfigured according to dynamic traffic is implemented.The remote management to erbium-doped fiber amplifiers and optical cross connect (OXC) and monitor to optical performance of data stream are achieved under the condition of the reconfigurable optical networks.The supervision of the wavelength stability,optical signal to noise ratio,time jittering,extinction ratio and bit error rate (BER) of any optical wavelength channel in the network is realized.The real time channel power equalization is also implemented under the dynamic routing condition.  

摘要：Based on the adjustable direction sensing model,we propose a Potential Field based Path Coverage Enhancement algorithm (PFPCE).This algorithm transports the pending issue into the study on the force laws to govern the interaction between centroid-centroid and centroid-trackpoint,in order to maximize path coverage while minimizing the overlapping sensing area among multiple neighboring video nodes,thus achieve better path coverage rate.Simulation results show the PFPCEalgorithm can obtain effective path coverage with small cost.  

摘要：As one of the support technology of wireless sensor network applications,node localization has been paid much attention to both academia and industry all the times.Existing localization methods are not suitable for 3-dimensional(3D)terrains due to their design for planar applications.According to the shortage of some existing algorithms proposed for 3D,in this paper we present a dynamic localization scheme based on spherical coordinates which translates the localization problem into a solution of multiple linear equations and utilizes the Cramer's rule to eliminate the probability of multiple solutions or void solution for the equations.Simulation results indicate that the relative localization error is 50.7 percent when 100 sensor nodes are deployed in 100*100*100m 3 scenarios with 10 meters' communication range and the anchor node density is 10 percent.The least square estimate(LSE)is applied to our algorithm to estimate the sensor nodes' positions and a result filtration strategy is used to reduce the localization error,the experiment data show that the improved solution outperforms the original scheme by 32.2 percent.  

摘要：Due to energy limitation,the wireless Ad hoc networks face to the challenge of lifetime,wireless resource utilized efficiency and delay.Now,the power control in the wireless Ad hoc networks has been the focus of extensive research,its main objectives are to reduce the total energy consumed in packet delivery,reduce the interference to other users in the network.For energy reserving,a method of Random Power Control (RPC) is proposed,the RPC lets the transmission power of nodes randomly distribute in an interval.By theoretic analyzing and numerical computing in the successful transmission probability and average transmitting power of RPC and fixed power control,it indicates that when choosing the proper minimum transmission power in the RPC,the successful transmission probability is almost the same as the fixed power control,the energy consumed is lower,and the lifetime of network is prolonged.  

摘要：As a representative of chain-based protocol in wireless sensor network,PEGASIS is an elegant solution on energy efficiency.However,there are still three deficiencies,inevitability of long link (LL) between neighboring nodes,unevenness of energy consumption distribution among nodes and too much overhead on LEADER node reelection strategy,with PEGASIS protocol.In this paper,we propose a new energy-efficient PEGASIS-based protocol called EEPB that uses distance threshold to avoid formation of LL and adjusts the frequency of LEADER node reelection to lessen overhead.Also unlike LEADER node election method used in PEGASIS,our proposed algorithm adopts the remaining energy levels of nodes and the distances between nodes and the BS (base station) to decide which node is qualified to be the LEADER of the chain.Our analysis and simulation results show that our proposed algorithm,without increase in complexity,provides more uniform energy consumption among nodes and can prolong network lifetime compared to PEGASIS.  

摘要：This paper proposes a minimum transmission power adaptive modulation algorithm to realize unequal error protection for data transmission in OFDM system.The power gains of sub-carriers in OFDM system are different,which is utilized to classify the sub-carriers into groups.Different group provides different transmission rate and transmission quality,thus different group transmits different kind of data.In addition,the modulation order and transmission power of each sub-carrier is adjusted by an adaptive modulation algorithm,so that the unequal error protection for data transmission is realized with minimal total transmission power.The simulation results indicate that the MTP AM-OFDM algorithm presented in this paper can provide different transmission quality for different kinds of data according to the QoS requirements of each data,as well as minimize the total transmission power.  

摘要：An algorithm on the blind estimation of the users’ chip sequence based on blind source separation technology is presented on the analysis of the DS-CDMA system model.Simulation results show that the algorithm can estimate the chip sequence of the different users accurately on the single or multiple path circumstance.At the same time,a blind multi-user detection algorithm based on blind source separation technology is also presented,which not only need not know the users’ chip sequence and channel information,but also make full use of the independence of different users.Therefore the performance of this multi-user detection algorithm presented in the paper is greatly improved relative to the traditional match filtering and de-correlation algorithm.When the signal to noise ratio(SNR)is equal to 6dB,the bit error rate(BER)of the algorithm presented is decreased by 2 orders of magnitude.  

摘要：In this paper,an model of adaptive multi-user diversity based on random beamforming and adaptive modulation MIMO-OFDM system is established. An resource allocation algorithm and simplified algorithm of adaptive multi-user diversity combining random beam-former and linear QR receiver are proposed. The system BER performance is deduced when the system throughput is maximal. Simulation result shows that the algorithm can make the system performance approach that of eigen-beamforming system even the user number is small. Multi-user diversity with antenna allocation can achieve better performance than that of eigen-beamforming system. Finally,adaptive subchannel coded modulation is adopted to improve system throughput and BER performance further.  

摘要：Two novel STTD scheme in CDMA system which combine the advantage of combating fading and improving the capacity of the spatial time transmit diversity (STTD) with the advantage of high efficiency of spectrum and robustness to the frequency selective channel of the multi-carrier code division multiple access (MC-CDMA) are proposed in this paper,the application of the two scheme in MIMO MC-CDMA system is also studied,we compared and simulated the proposed two scheme with the conventional STTD based on the spatial time block code (STBC) in MIMO CDMA system and MIMO MC-CDMA system respectively.  

摘要：In this paper,a new family of hopping sequences called an-optimal Hamming-correlation set for use in frequency-hopping(FH)code-division multiple-access(CDMA)system is proposed.The construction of the new hopping sequences is based upon the polynomial theory and discriminant theory over the finite field.The polynomial hopping sequences we present are based on polynomial with 2 degree and 3 degree.Comparing with the original method,this method can get hopping sequences with optimal Hamming-correlation and are good candidates for the anti-interference frequency-hopping communication systems in army.In addition the method for constructing the hopping sequences with optimal Hamming-correlation is very simple,feasible and has better applied foreground.  

摘要：By applying tomography theory which is highly developed in fields such as medical computerized tomography and seismic tomography to communication network,network tomography has become one of the focused new technologies,which can infer the internal performance of the network by external end-to-end measurement.In this paper,we propose a novel Inference algorithm based on the recurrent multilayer perceptron(RMLP)network capable of tracking nonstationary network behavior and estimating time-varying,internal delay characteristics.Simulation experiments demonstrate the performance of the RMLP network.  

摘要：Image registration for digital subtraction angiography (DSA) is an important preprocess for 3D reconstruction of blood vessels based on DSA image sequence.A new image registration algorithm based on weighted histogram for DSA image is firstly proposed in this paper.The registration method is divided into two phases,i.e.motion correction and gray-level registration,according to the two different types of noise.A series of methods are introduced to improve the performances of traditional DSA registration algorithms,including selection of control points on the basis of edges in subtraction image,construction of new similarity measure based on the energy of weighted histogram of differences,generation of blood exclusion template and determination of gray value shifts according to the new weighted histogram of subtraction image.Various experimental results have demonstrated that the proposed algorithm is able to eliminate the motion noises and gray noises more effectively.The visualization of blood vessels is enhanced and the quality of subtraction image registration is improved therefore.  

摘要：The existing fragile watermarking algorithms almost can’t recognize the modification made to the watermarked image is on the image content or on the embedded watermark.In this paper,a novel fragile watermarking scheme is proposed.The recovery watermark of each block is embedded into the Hypo-LSB of the corresponding excursion block selected by a key,and the authentication watermark of each block is embedded into its LSB.Theoretical analysis and simulation results show that the proposed algorithm can not only thwart the VQ attack and locate tampered blocks accurately,but also discriminating tampering watermark from that of content.And in some case,it can restore the tampered region effectively.  

摘要：In matrix transform based image scrambling,the cost to restore image by periodicity is expensive.To restore image by inverse mapping,existing methods do not solve the problem computing inverse matrix in Z _<em>N.To address it,this paper expanded the method getting inverse matrix by adjoint matrix to Z _<em>N through constructing mapping regulations.To decrease the expensive cost of it,this paper generalized Doolittle decomposition and Crout decomposition into Z _N ,which solves the inverse problem of any n dimensional matrix scrambling transform where every order rank principal minor of transform matrix is prime with N.To weak the expanded Doolittle decomposition and Crout decomposition condition,this paper expanded Gauss-Jordan elimination into Z _N and gave the inverse matrix generation algorithm and simplified algorithm.The proposed methods can get the inverse matrix in Z _N directly to restore image without computing the periodicity.The experiments show the proposed methods feasibility and validity.  

摘要：Kerdock code and Preparata code are two certain notorious nonlinear binary codes,which have more codewords than any comparable linear code have presently known.In 1994,these two codes are proved to be extended cyclic codes over Z₄ under Gray map by Hammons,which greatly simplifies encoding and decoding.F₂+uF₂ is a ring with four elements which shares some good properties of both Z₄ and F 4.Coding theory over this ring has recently received a great deal of interest among coding theorists.In this paper,the concepts of Kerdock code and Preparata code are first introduced into the ring F_p+uF_p,and it is showed that they are dual to each other;the trace representation of Kerdock code over this ring is given.In the case p=2,we give the relations of these two codes with Reed-Muller codes over F₂;and we prove that the binary one order Reed-Muller code is the Gray image of a linear subcode of Kerdock code.  

摘要：A non-authenticated group key agreement protocol cannot provide participant and message authentication,thus it must depend on an authenticated network channel or use another scheme to provide authentication.This paper indicates that Horng’s group key agreement protocol which based on the authenticated broadcast channel is unable to withstand the disruption attack of malicious participants in group.This attack leads that other honest participants will not be able to correctly agree on a group key consistently.In this paper,an improved protocol is proposed.The proposed protocol which joins the message authentication method in original protocol can detect the malicious participant.Under the random oracle model,paper proves the proposed protocol can withstand the interrupted attack from malicious participant.  

摘要：In the verifiably encrypted signature (VES) schemes from pairings,the pairing operations are the most time-consuming.So,in the schemes of such kind,the pairing operations should be less used.Based on a new construction of the signature scheme from pairings,a novel randomized and verifiably encrypted signature scheme is proposed,in which there is the least pairing operation.That is,there is only one pairing operation in the new scheme.Therefore,compared with the other randomized VES schemes from pairings,the new scheme is more efficient.The security of our scheme depends on the hardness assumption of k-CAAP (collusion attack algorithm with k traitors problem) and DLP (discrete logarithm problem).  

摘要：For solving the issue of keys management in the mass wireless sensor networks,a Two-Level Key Management Scheme which will be used in clustered sensor networks based on EBS system was proposed.This scheme runs from network’s deployment to the end of lifecycle,to manage all of the nodes’ keys.Regarding of the specialty of sensor networks,this scheme consists of three phases which are initialization phase,working phase and update phase.The experiments show that the sensor nodes only need to store fewer keys and the whole network performs good ability in keeping network flexibility.  

摘要：Considering limitation of power,computation and storage resources of wireless sensor networks.The paper proposes an efficient key agreement scheme for wireless sensor networks.Firstly,the proposed scheme pre-distributes network system parameters using identity based encryption algorithm and computes nodes’ parameters.Then it broadcasts node’s identity to networks and exchange parameters between nodes and computes nodes’ key using Diffie-Hellman key exchange technology and identity based encryption algorithm.Final of the proposed scheme is the message encryption and decryption operations based on symmetric cryptography,for example IDES.In the proposed scheme,key exchange technique and identity based encryption algorithm make it safer,Analyses show that the proposed scheme needs less resource than other schemes need when we apply it to wireless sensor networks.Compared with traditional public key scheme and symmetric key scheme through comprehensive simulation,the simulation results show that our key agreement scheme is efficient for wireless sensor networks.  

摘要：Inspired by the similarity between radial basis function (RBF) network and immune system,a RBF online training algorithm based on immune model is proposed to solve dynamic problems.The algorithm takes its inspiration from the dynamic adjustment mechanism of natural immune system to combat an ever-changing cast of antigens.Immune operations such as initial immune coverage,cross-reactive response and immune vaccination are implemented in the algorithm to improve the efficiency,precision and dynamic performance.Through these immune operations the RBF network can quickly adjust its structure and parameters according to changes in training set.Computer simulations demonstrate that the RBF network designed by the algorithm has good precision and generalization ability in dynamic environments.  

摘要：Perceptual hashing is a class of one way mappings from multimedia presentations to a perceptual hash value in terms of their perceptual content.It features the perceptual robustness and security.Perceptual hashing could be applied to multimedia content identification,retrieval,authentication,etc.On the basis of the human perceptual model,definition of perceptual hashing is proposed in this paper,as well as the properties and the general descriptions.Its typical algorithm reviews,application scenarios and benchmark are presented.The prospect of perceptual hashing algorithms and techniques is also discussed.  

摘要：Wireless multimedia sensor network is a novel information acquiring and processing technology.Its potential applications span a wide spectrum from military to industrial,from commercial to environmental monitoring.The distinct features of wireless multimedia sensor networks,such as various media category,great data amount,complex processing task,make the issue of QoS guarantee in wireless multimedia sensor networks is challenging.This paper explores this issue,and discusses the QoS requirements and technical challenges faced in this field.In particular,this paper summarizes the current research progresses from six aspects:MAC layer,network layer,transport layer,application layer,cross layer and middleware.Finally,the problems to be solved and the research trend are also pointed out.  

摘要：All internet routers contain buffers to store packets.Selecting appropriate buffer size can not only ensure router performance,but can also contribute to reducing uncertainty in the internet.This paper aims to size buffers for forwarding engines known as the main part of a router.First,a high-speed pipeline which is designed for forwarding engines is presented,and its memory analysis model is also given,then,the memory demand of forwarding engines is analyzed under two situations:the forwarding capability being not less than and less than the input rate.Our analysis results and experiments both show that,when the forwarding capability is not less than the input rate,a forwarding engine only need to buffer a several packets of maximum length,when the forwarding capability is less than the input rate,a forwarding engine only needs to buffer about ten packets in the view of buffer use efficiency,and further increasing the buffer size will have little effect.  

摘要：The draft IEEE 802.11e standard aims at providing quality of service (QoS) support in 802.11 wireless local area networks (WLANs).Enhanced distributed coordination function (EDCF),being the fundamental medium access control mechanism in IEEE 802.11e,can only provide service differentiation but offers no QoS guarantees.While service differentiation does not perform well under high traffic load conditions,call admission control (CAC) becomes necessary in order to provide and support the QoS of existing calls.In this paper,we first establish a new 3-D Markov model to analyze the non-saturation throughput and mean access delay performance of differentiated service provided by EDCF.Based on the new model,we propose a novel CAC strategy in WLANs based on utility function,which can maximize the total income of WLAN.Simulated performance results demonstrate the effectiveness of the proposed CAC algorithm.  

摘要：In Virtual Bridged Local Area Networks,asymmetric VLAN was brought forward in order to segregate users in different VLAN.At the same time,all users regardless of their VLAN membership can access shared resources in server VLAN.In this paper,we first analyzed the shortage of SVL-based Asymmetric VLAN and IVL-based Asymmetric VLAN,and then we provided a novel CSVL MAC learning and forwarding model and CSVL-based Asymmetric VLAN.Our experiment shows CSVL-based Asymmetric VLAN can achieve the function of Asymmetric VLAN perfectly without adding an extra amount of MAC address entries in FDB.Furthermore,CSVL-based Asymmetric VLAN can reduce the complexity of Asymmetric VLAN and decreases the usage time of CPU comparing with IVL-based Asymmetric VLAN.  

摘要：The pitch contents in the spectrum of voiced segments in wideband signals do not extend over the whole spectrum range,and the amount of voicing shows more variation compared to narrow-band signals.Thus this paper presents a new paradigm to improve the closed-loop pitch analysis to better accommodate the variations in the voicing level.The paradigm is an adaptive pitch searching paradigm which automatically selects an optimal low pass filter applied to the past excitation based on the inter-band waveform cross correlation.The complexity of new algorithm is only 54% of that of adaptive multi-rate wideband (AMR-WB) speech codec selected by 3GPP.We verify that the performance,both in terms of weighted signal-to-noise ratio (SNR) and perceptual quality,is higher as apposed to that of AMR-WB.  

摘要：As to small amounts of training and test speech data,it proposed a new speaker recognition algorithm.By the kernel mapping,it used the fuzzy vector quantization to quantize the speakers’ speech features in the high dimensional feature space.In order to improve the discriminations of different speakers,it presented a novel weights assignment method.It assigned the lager weight to the code vector with higher discriminative power.Then,it used the codebooks and weights to form the speakers’ database.In the matching phase,it proposed a fuzzy kernel weighted nearest prototype classifier,which can identify different speakers in the high dimensional space.Experimental results show that when the training speech data is less than 8s,and test speech data is 1s,this algorithm can get good performance.  

摘要：Transmit power control technology contributes as a fundamental part in fault tolerant topology control,through which reliably-connected and highly efficient topology can be constructed.Centralized Transmit Power Control algorithm (CTPC) is firstly proposed.Its correctness,as well as its optimal property,namely minimizing the maximum communication radius,is formally proved.CPTC is then extended to two distributed versions,namely Global knowledge based Distributed Transmit Power Control algorithm (GDTPC) and Localized Distributed Transmit Power Control algorithm (LDTPC).Their corresponding correctness is proved and optimal property is discussed in details.LDTPC employs local knowledge only and suits well in large scaled wireless sensor network.  

摘要：Digital angiography is one of wide-using technique of visualization in modern medical treatment.However,it seems hard for doctor to diagnose cardio-vascular diseases by angiograms due to noise influence.It is difficult for traditional techniques to enhance vessels,especially some distal vessels,from the angiograms with low contrast and complex background.Due to coherent configuration of vessels in local space,an angiogram enhancement method is proposed,which integrates contextual information based on a co-circularity constraint.We performed this method on angiograms in our experiment,making vessels to pop out perceptually from their background,and the result was quite satisfactory.  

摘要：We propose a novel video denoising method with 3D Context Model in Surfacelet Transform Domain(3DCMST)in this paper.In order to take advantage of the characteristic of the coefficients,the Context model was extended from 2D to 3D.The ST coefficients were divided into several parts according to their energy distribution by 3D Context model and each part had independent energy estimate and threshold.Experimental results show that the proposed method achieves better denoising performance than other 3D or hierarchical 2D denoising methods,and remarkably improves the PSNR of video about 2dB.In terms of visual quality,the proposed method can effectively preserve the video detail,and the trajectory of motion object is very smooth,which is especially adequate to process the video frames with acute movement and plenty of texture.  

摘要：In order to bring the speed potential of the middling resolution ADC to play effectively,predigest the design of bioelectricitical amplifier and reduce its cost,oversampling is used to detect bioelectricity in this paper.Human’s ECG detection based on oversampling is used to check it’s validity,and three sample methods are utilized to experiment.The results show that the ECG has better precision and SNR by the method of oversampling than the conventionality.This method can be applied to various bioelectricity signal detection widely.  

摘要：The previous distributed ring signature schemes proposed by Javier Herranz inherit key escrow problem of identity-based public key cryptography.In this paper,we propose two secure certificateless distributed ring signature schemes.Such schemes provide unconditional anonymity to a subset of users who sign a message on behalf of a family of subsets.Our first scheme is based on bilinear pairings,and can be used for general families of possible signing subsets.Its idea comes from that of Schnorr’s ring signature scheme.The second scheme is based on Shamir’s secret sharing scheme and more efficient for threshold families of subsets.Futhermore,in certificateless scenarios,the trusted authority takes part in generating entities’private keys,but he does not access to these private keys.So our two schemes retain the desirable properties of identity-based distributed ring signature schemes and avoid the inherent escrow of them,therefore actually possess the alleged unforgeability.