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摘要：Mobile Ad Hoc Network(Manet) is a new kind of wireless mobile network.Because of its self-organization,dynamic topology,distributed control and multi-hop routing,traditional security mechanisms are not sufficient to secure Manet.Therefore,some new security mechanisms must be used.Security threats faced by Manet are studied,and a secure distributed authentication scheme based on multi-hop signing with encrypted signature functions is proposed.Here mobile cryptography and (n,t) threshold cryptography distributed authentication are combined,and distributed fault tolerance processing algorithm and private key share refreshing technology are used to detect and prevent attackers from violating authentication using digital signature and protect private key shares and authentication private key from leaking.  

摘要：The technique of Stochastic Petri Nets(SPN) was wildly used in the field of performance evaluation in the past 20 years.But the SPN model is still in face of the problem of explosion of the state space.And if in stochastic modeling the idealized assumption of exponential distribution is removed,the resulting stochastic process is non-Markovian.In this paper,we present Queuing Petri Net including Non-Markovian processes (NM-QPN),a novel high level modeling technique,which is based on the former research.This modeling technique integrates the characteristics of Queuing Nets,Stochastic Petri Nets and simulation solving.A complete solving scheme of NM-QPN was presented.The algorithm of Flow Equivalent is used to analyze and simplify the Markovian processes parts in the model so that the state space will be greatly reduced,and then simulation technique to solve the remaining non-Markovian processes was used.  

摘要：A novel inversion method combining the Born iterative method (BIM) with multi-grid technique is developed to solve the nonlinear inverse scattering problem for two-dimensional lossless dielectric inhomogeneties using time-domain scattering data.In the inversion procedure,the size of the discretization grid inside objects is reduced gradually.In the previous inversion procedure,because the condition number and dimension number of the matrix obtained by discretizing the integral equation are relatively small,this method has a good robustness and ability to converge more easily to the true profile.Several examples are given to show that this method reduces vastly computational time of the inversion procedure and can accurately reconstruct the higher-contrast scattering object than that of the BIM.It is more important that this method has the simplicity and can be used to other arbitrary inverse scattering method.  

摘要：This paper proposes a new persistent contention-based real-time Ethernet MAC protocol that provides a predictable upper bound for the delivery delay of real-time frames.Under the new protocol,if a collision occurs,the real-time station keeps on sending a contention signal instead of stopping transmissions.Through this persistent transmission mechanism the protocol informs non real-time and low-priority real-time stations to stop transmissions and leaves the bandwidth to high-priority stations.Moreover,this protocol is compatible with Ethernet MAC protocol and thus real-time stations can coexist with standard Ethernet stations in the same system.The paper describes the protocol in detail and analyses the delivery delay for real-time traffic.The analysis and the simulation results demonstrate the method is correct and efficient.  

摘要：Consider a system composed of N nodes that can be faulty or fault-free.The purpose of system-level fault diagnosis is to have each fault-free node determine the state of all nodes of the system.Probabilistic diagnosis algorithm is very important in the system level fault diagnosis research.A system-level fault probabilistic diagnosis algorithm based on parallel group was proposed,PGSFPD algorithm,and the software emulation system of system-level fault diagnosis was presented.Experimental results are given through simulation of the algorithm for large systems of from 200 nodes to 1000 nodes under the emulation system.The results indicate the PGSFPD algorithm has better performance than the Somani & Agrawal algorithm,which is a classic probabilistic algorithm in system level fault diagnosis.  

摘要：The accelerated-life tests with high stresses and noise spectrum measurement at normal bias conditions are performed for Al-based interconnection in VLSI,and the variation of frequency exponent γof 1/f ^γ noise with the electromigration evolution during the test is observed.It is found that the abrupt change of the exponent γ,from 1.0 to 1.6 above,occurs after a period of the test.The change may be caused by the voids induced by electromigration,and hence the invertible structure variation in the metal thin films starts to be formed at the time.Therefore,the exponent γof 1/f ^γ noise can be used as an indicator to evaluate the destruction to thin film interconnection induced by electromigration.  

摘要：Additive noise and instantaneous disturbance may produce adverse influences to system identification.However,an output of a real system is often affected by both noise and disturbance.To reduce these disadvantageous influences,system output data polluted by additive noise are repeatedly decomposed,denoised and reconstructed employing different wavelet functions and different threshold methods.After the output data are denoised by wavelet approaches,the identification results obtained by employing the least squares(LS) identification method are still unsatisfactory due to instantaneous disturbances.Hence,An identification algorithm based on wavelet and least absolute errors (WLA) is proposed.The simulation study shows that the presented approach can overcome the influences of noise and disturbance simultaneously.  

摘要：The future electronic cash should have all the advantages of note and not have the disadvantages of it.The system presented in the paper has following characteristics:revocable anonymity;off_-line;as simple as eCash^TM in application and payment processes;overcome the two flaws in the eCash^TM system:1.anyone who somehow observes the eCash^TM Coins can spend them;2.when the dispute about if one Coin has been doubly spent between Bank and a user takes place,it should be impossible for other person to arbitrate it.So the system should be one of the most practical systems proposed at present.  

摘要：The active phased-array antenna not only can improve the communication system performance,but also can extend its function,so it is used in communication system more and more widely.This paper introduces an active phased-array antenna system that has eight antenna elements without high frequency phase shifters.The system consists of planar array,digital T/R modules,receiving DBF and system control/analysis software etc.The basic theory is:in transmitting mode,the traditonal high frequency phase shifters and attenuator can be replaced by direct digital synthesis(DDS).Because the operation frequency of DDS is very low,the frequency must be converted to needed operation frequency(2.0GHz) by upper frequency conversion.In transmitting mode,through controlling DDS,it produces the amplitude and phase weights needed by transmitting beam,and the local oscillation signal needed by upper frequecy conversion.In receiving mode,through controlling DDS,it produces the local oscillation signal needed by down frequency conversion of the receiving signal.Then the DBF is used to form the receiving beam.This paper introduces in detail the ways and results of the experiment of the active phased array antenna based on DDS.Through the research of eight-element active phased array antenna based on DDS, the notable virtues of DDS technology in phased array antenna,and the potential application market of the phased array antenna in communication are proved.  

摘要：In recent work on decoding space-time codes,it is assumed that a channel estimate is obtained.To estimate the channel increases the computation load and a loss in performance of decoding is incurred by the error of channel estimate.In this paper,we propose a new decoding algorithm for space-time block coding.Combined with the structure of space-time block coding,the subspace of the transmitted signal are exploited to carry out the decoding without knowledge of the channel.Simulation results show that with the increase of the precision of noise subspace,the performance of our decoding algorithm approaches that of the coherent decoding algorithm with knowledge of channel.  

摘要：The availability of fully polarimetric SAR data makes it possible to utilize the co-polarized and cross-polarized images for speckle reduction.In this paper,many of the despeckling processing methods is introduced in detail.The part weighting algorithm is proposed.With minimum resolution broadening and coupling between polarimetric and frequency channels,a series of experimental results about image speckle reduction demonstrate the effectiveness and less computational load.  

摘要：In the existing method of digital watermark,for embedding watermark information,authors modify more or less original image data through various methods to limit its robustness and security.Zero-watermark is a new digital watermarking technology without modifying the data of original image.In this paper,we construct zero-watermark using high-order cumulants.The result of experiment shows that this zero-watermark constructed by this method has good performance.  

摘要：The quantization scheme for the iterative belief propagation (BP) algorithm of low-density parity-check (LDPC) codes is studied.The effects of the bound,resolution,and other parameters for uniform and nonuniform quantization schemes are discussed.Good performance of decoding under properly designed quantization can be obtained as shown by simulations.Furthermore,we found that the quantization of high order for the mid-variables of BP decoding algorithm can improve the performance and reduce the error floor of LDPC codes at regions of high signal-to-noise ratio.  

摘要：It appears many real-time applications with conversion delay between binary and decimal algorithms is a bottleneck of system performance.This paper introduces a kind of shift-based algorithm in order to shorten this delay with minimum cost.Based on the principle of data representation of binary and decimal algorithms,both binary-to-decimal and decimal-to-binary algorithms are deduced mathematically in equation. They are featured as converting data value through shift operation.Double of BCD,constructed to be Logic N,is atomic operation of binary-to-decimal bit-shifting conversion and half of BCD,constructed to be Logic M,is one of reverse conversion.Without carrying propagation froLogic M N to Logic N or froLogic M M to Logic M,the conversion speed only depends on the longest combinatorial path of Logic N or M.These radix-2^<em>r algorithms,i.e.by one-bit shift per cycle,is expanded to radix-2^<em>r algorithms,i.e.by multi-bit shift per cycle,to accelerate the conversion speed further.Finally,it shows that the shift-based algorithms are much faster than other algorithms by comparisons of these conversion algorithms.  

摘要：Role authorization constraint is one of focal points of RBAC research.It is a difficult problem to effectively represent the authorization and activation order constraints of multiple roles.Novel role authorization coordination relations were presented and coordination order relations such that existing role relation concepts are expanded.It is able to make RBAC represent complex order constraints when granting or activating multiple roles.The new Petri Net to analyze and simulate the consistence of role authorization coordination as well as its order relation is proposed.  

摘要：A new multipath multistage interconnection network called the recursively constructed composite banyan network is proposed.The basic building blocks of the network are 3×3 switching elements.The advantage of this network is to resolve the problem that the composite banyan network proposed by Seo and Feng can't perform arbitrary permutation by adding middle stages.The network can easily generate a primary routing tag and more alternate tags through simple binary operations,which increase the degree of fault-tolerance.A permutation routing algorithm suitable for the network is introduced.The major feature of the network is pre-fault-tolerance.By setting a flag bit to identify whether the status of one witch is usable or not,the network can choose appropriate routing tag to avoid the switch that can't work in advance.  

摘要：In this paper we propose a method of wavelet coefficient compensation with noise model.In the wavelet transform domain,the wavelet coefficient which is truncated to 0 by quantizer is simulated by noise model.According to these parameters of model,the stochastic texture is synthesized at decoder to improve the distortion and improve the visual quality of decoded image.The result shows that the bit rate is only 0.013 bpp for the parameter of model,and at the same bit rate,compared to the JPEG2000,the visual quality of decoded image is much improved.  

摘要：By analyzing the pattern of the uniform circular array(UCA),a dually weighted adaptive antenna zero processing method is put forward in this paper,based upon the rules of the maximum directivity and the maximum signal-to-noise ratio.The question of one dimension adaptive zero forming is discussed with the method in the case of UCA,and the correctness of the method is proved through computer simulation.  

摘要：The artifacts of wavelet spatial adaptation de-noising method is discussed,and the stationary wavelet transform is proposed.Harr wavelet is selected to decompose the noisy ECG signal for several levels.The noise mean square σ_j is estimated by the stationary wavelet transform details at every level.The detail d_j goes toward 0 by threshold σ_j 2lnn ,where n is length of the detail.The recovery signal is reconstructed and experimental result shows this de-noising method suppress Gibbs phenomena and reserves geometrical character of ECG signal.  

摘要：Method of LFM signal detection by Wigner_-Transform and its evaluation is presented.A discrete algorithm is devised here for this method and multicomponent LFM simulation proved its expected performance.  

摘要：Pseudo random sequence has broad applications in stream cipher,channel coding,and spread spectrum communication.Linear complexity and its robustness are important features of pseudo randomness.C Ding presented a novel class of sequences with ideal autocorrelation and almost balanced 0-1 distribution.This paper discusses other pseudo-randomness of such sequences.The major results are the following:such sequences have quite satisfactory linear complexities;their linear complexities do not degenerate under single symbol substitution.  

摘要：Using line of sight (LOS) measurements from space-based infrared sensors,ballistic trajectory estimation problem of ballistic missile is studied in this paper.Taking into account poor target motion observability,an improved position constrained Gauss-Newton algorithm is proposed to solve maximum likelihood estimation problem of trajectory.Monte Carlo simulation verifies the efficiency of this algorithm.And,estimation error is analyzed.  

摘要：This paper proposed a new scheme to segment an image into meaningful regions based on its intensity distribution and spatial information.First,an image is separated into a large number of small partitions by a highly optimized watershed algorithm;then,the characteristic parameters are calculated for each partition,and the topological relation is determined between each other;finally,fuzzy C-means clustering algorithm is used to obtain the final segmentation result.The result shows that this scheme can obtain more meaningful regions with less time consumption than that by the direct fuzzy C-means clustering algorithm.  

摘要：This paper proposes a new security management system for the mobile network,which uses the asymmetric cryptosystems to authenticate the mobile users.As the visited network can authenticate the user independently in roaming,the system is called independent security management (ISM).An authentication protocol based upon ISM is given.As shown in our analysis,the greatest advantage of ISM over other security managements is that the security responsibility is made clear and the authentication procedure is more efficient.  

摘要：Multiple Flow Regulator (MFR),a novel network component that can be implemented simply,is proposed in this paper.MFR can identify the flow with the biggest rate inside an aggregated flow and separate it from this aggregated flow.MFR can also be used in measurements of characters of an aggregated flow,and to penalize non-responsive flows and so on.Static mathematical model of MFR is analyzed in this paper.Extensive simulations are conducted based on ns2-generated flows.Simulation results show that,the working character of a MFR coincides with the mathematical descriptions given in this paper.  

摘要：To obtain partial information of network's resources,which indicates what fraction of each link's bandwidth,is currently used by working paths,and is used by protection paths,is feasible in IP over WDM(Wavelength Division Multiplex) networks using MPLS technology.In this partial information scenario,this paper proposes a new dynamic routing algorithm of protection design for IP over WDM networks.For working paths selection,the algorithm makes a tradeoff between the routing costs and the corresponding transmitting length.As for protection paths selection,a tradeoff between the sharing of the protection paths and the associated transmitting length is made.Simulation results show that the developed load balance based algorithm performs very well in terms of performance metrics such as the number of rejected requests and the network link load balance.  

摘要：This paper presents the application of heating load prediction and predictive control in the heat supply system for energy saving and high grade heat supply.First,it introduces time series analysis principle.Then,heating load and model error prediction are given by this principle.The load forecast is used as set point of heat supply system,and model error is used as corrected value of predictive control.Finally,the application of two prediction methods in heat supply system and simulation result are given.  

摘要：Starting with investigating the Haar scaling function,the scaling coefficient function is first presented.Then the Battle-Lemarié basis is extended to the generalized Battle-Lemarié basis by introducing time-shift factor to the scaling coefficient function of the Battle-Lemarié.The rationality of the extending method,which is used in this paper,is theoretically proved.Some basic properties of the generalized Battle-Lemarié basis are also discussed.Our research results show that all the Battle-Lemarié bases inherit many good properties of the original Battle-Lemarié bases,such as orthonormality,time frequency localization,exponential decay and so on.Meanwhile a series of neoteric symmetric multiresolution analysis basis are generated.The generalized Battle-Lemarié wavelets are better than the corresponding original Battle-Lemarié wavelets in regularity.  

摘要：A new adaptive filtering algorithm is proposed in this paper.The proposed algorithm is of simple structure,medium computational complexity and fast convergence,and makes up for the defects that general LMS algorithm is of less computational complexity but of slow convergence and the Affine Projection Algorithm (APA) is of fast convergence but of large computational complexity.The structure of the new algorithm is much simpler than APA and its improved version,but it has the same convergence as APA.We not only analyses its performance but also succeed to apply it to multi-channel echo cancellation.Simulation in MATLAB shows its computational complexity is much lower than Sankaran's(1997) and Benesty's(1996) but they have the same convergence and accuracy.Hence it has better tracking ability.  

摘要：Broadcasting is an original and important operation for wireless networks.The Competitive Broadcasting Algorithm is a competition-based broadcasting algorithm for mobile ad hoc networks.Analyses and simulations show that Competitive Broadcasting Algorithm can save a large number of redundant rebroadcasts compared with Flooding Scheme,an intuitive broadcasting method.And it also improves the network broadcasting performance;increases the network throughput.In addition,the idea of Competitive Broadcasting Algorithm can also be used in other applications,such as routing discovery schemes,to enhance the performance.  

摘要：The semantics for interoperations among peers is expressed in a logic of mental attitudes and action,formalized in a first order modal language,and provides an unambiguous reference point for implementations of interoperations.There exists some defects in the semantics of traditional persistent goal,which make initiator lose their controls of interoperations.In order to solve this problem,this paper brings forward the concept of degree of perseverance,which means the grade of commitment of interoperations.Perseverant goal,based on the concept of degree of perseverance,is an improvement on persistent goal,and realizes supports of different levels of commitment for interoperations.  

摘要：Access control is the key problem in a hierarchy system.An access control scheme based on Lagrange's interpolation polynomial is proposed,and the property is analyzed from the view of time and space complexity.The scheme is of very strong security,and it allows all users to select their own secret keys.A general access control scheme in a hierarchy is proposed based on threshold secret sharing scheme.Its basic idea,constructing algorithm and security are discussed.  

摘要：A heretofore unsolved problem of great archaeological importance is the automatic assembly of fragments of cultural relic from the hundreds(or thousands)of sherds found at an excavation site.This paper presents a novel method for searching for similar fragments of 3D curves.In this method,a Hash vector(a vector of real numbers) is associated with each fixed-length fragments of 3D sherds.Each vector consists of low frequence components of Fourier-Like spectrum for the distance between profile curve and the centroid.Then we can analyze the similarity between fragments by evaluating the difference between Hash vectors.The novel aspect of the method is that the following property is proved theoretically:if the distance between two fragments of curve is small,then the distance between the Hash vectors is small.  

摘要：Based on the new-coming H.26L video compression standard,an RD optimal Macro-Block mode decision scheme for Internet error channel streaming is introduced.The scheme employs the luminance Rate Distortion (RD) optimal mode decision scheme so as to take the effects of video encoding distortion and the channel error propagation to get higher error robustness for error transmission.Experimental results under real Internet channel condition fully prove its superior adaptive error resilient capability.  

摘要：With the development of nano-fabrication techniques,nano-structure devices will be the basis of the next generation integrated circuits.We report process of Si quantum wire and dot based on EBL and RIE processes and process of nano-structure metal gate based on EBL,electron beam evaporation and lift-off techniques.Single electron transistors (SETs) on p-type SIMOX substrates were also fabricated based on the processes.Coulomb blockade and single electron tunneling are observed in the SETs.  

摘要：This paper presents a universal circuits theory for binary,multiple-value and adiabatic circuits,i.e.theory of three essential circuits elements-signal,network and load.A versatile N+1 value algebra is firstly defined,and then by means of N+1 value algebra the operater transform theorem and some multiple-value circuits formulae are proved.In order to put it to good use,the component level circuits structures is deduced from N-value circuits function or flip-flops characteristic equation.The above theory is extended to adiabatic circuits while N tends to infinity,so that quantitative analysis and synthesis for adiabatic circuits are made with universal theory under the restrictive condition,such as the cross-coupled adiabatic flip-flops and adiabatic synchronous sequential circuit which are vertified by Computer simulaton.  

摘要：A 14 bit,50MS/s current CMOS DAC is introduced.The DAC core is composed of an array of 31 thermometer-coded MSB current sources,15 thermometer-coded upper LSB (ULSB) current sources,and 5 binary-coded lower LSB (LLSB) current sources.Moreover the 5 MSB has a background self-trimming to meet high resolution.The new analog self-trimming technique introduced here does not need a replacement to replace the self-trimmed one.The circuit was fabricated in a 0.25μm CMOS technology.The die area is 3.54mm².The measured results have shown that the circuit has more than 12 bit static resolution.  

摘要：A dispersed-pulse CELP (DP-CELP) speech coding algorithm is proposed.The excitation is generated by means of convoluting the algebraic codevector with a fixed dispersion pulse.The constructed speech quality is efficiently improved with this excitation,but the search complexity for algebraic codebook not increased.The informal subjective test shows that the speech quality for this DP-CELP algorithm at 4 kb/s closes to that of a G.723.1 codec at 6.3 kb/s.  

摘要：Management information model conformance testing is carried out according to the corresponding Implementation Conformance Statement (ICS) proforma.Each kind of information model should have its own ICS proforma.In this paper,SMIv2-based ICS proforma is proposed based on the ITU-T methodology for ICS proforma and the grammar rule of SMIv2.Its provides standard format for interface implementers or suppliers to state their implementation of a management information model and can meet all the requirements of information model conformance testing for SNMP(Simple network management protocol)-based network management interface.An MIB-file-based ICS auto generation method is also presented.The system developed by this method is being used for conformance testing for SNMP interface.  

摘要：In this paper,a new Matched Transform based on phase compensation is proposed.By constructing the matched function,this new transform can make the signal energy concentrate in the transform domain.And as the result,the good performance of signal detection and parameters estimation can be obtained.The chirp signal is analyzed in detail as an example.The comparison with other methods shows that the new algorithm is more robust and can obtain the lower sidelobes and better resolution.In addition,the Matched Transform combined with Genetic Algorithm is also studied to detect and estimate the complex signal.The effective parameters estimation and high convergent speed can be achieved.The simulation results prove the validity of the whole algorithm.