最新刊期
卷 32 ， 期 2 ， 2004
- 摘要：Printed character image contains the information of characters and the information of fonts.Font information is essential in layout analysis and reconstruction,and is helpful to improve the performance of character recognition system.An algorithm for font recognition of single Chinese character is proposed,which needs no prior knowledge of characters.The new algorithm can recognize the font of a single Chinese character while existing methods are all based on a block of text.We extracted wavelet feature from a single character image and employed Box-Cox transformation and LDA technique to get the final feature for font recognition,which was used by a MQDF classifier.Experiment shows that our method can recognize the font of a single Chinese character effectively and a recognition rate of 97.35% is achieved.关键词：font recognition;single character;wavelet feature;LDA;MQDF2|2052|5更新时间：2025-07-16
- 摘要：In some representative methods of triangle mesh compression,the connectivity is encoded using some kinds of traversal methods,the geometry is encoded by predicting the coordinates of each vertex with neighboring vertices along the traversal path.Their main drawback is the prediction only reduces the correlation between each vertex and its neighboring vertices in the traversal path.The coordinates of all vertices in a local spatial region have strong correlation.although these vertices are neighboring in space,they are usually not neighboring in the traversal path.Inspired by image compression standard JPEG,a novel block DCT geometry compression method is proposed.The input mesh is partitioned into many blocks.Given the fact that if all vertices in a block are ordered in traversal order,their coordinates distribute periodically,we use 1-dimentional DCT transform to reduce the correlation among all vertices in a block.The experimental results show the block DCT method has good geometry information compression performance.关键词：triangle mesh;compression;geometry information;block partition;DCT2|1094|0更新时间：2025-07-16
- 摘要：Dynamic meshing integrates nonlinear shape normalization into feature extraction without introducing any new distortions.A feature extraction method using overlapped dynamic meshing is proposed for handwritten Chinese Character Recognition.a density image is defined for an input character image.Based on the density image,overlapped meshes and fuzzy membership are dynamically calculated.Fuzzy contour direction feature (FCDF) extracted with the proposed method is introduced.Experimental results show that significant improvement in recognition rate is yielded compared to conventional static or dynamic meshing methods.关键词：handwritten Chinese character recognition;feature extraction;fuzzy theory2|1049|6更新时间：2025-07-16
- 摘要：Several basic blocks could be merged into a hyperblock in predicated execution so that instructions could be scheduled on a larger scope and more instruction level parallelism could be extracted.But it also brings some new challenges to traditional optimizers without predicate analysis,which can only yield conservative results.But unfortunately,limited by predicate representations,current methods need reconstructing control flow information before analyzing predicate relationships,which limits the effectiveness and efficiency of optimization.A new representation based on path information is proposed in this paper,which can convert predicate definitions into equivalent domain codes.And a global predicate relationship query system is constructed based on it.Experiment results indicated that precise and efficient global predicate analysis could be achieved with this system and the performance of optimized codes can also be improved with little impact on compilation efficiency.关键词：predicated execution;predicate analysis;path;domain2|908|0更新时间：2025-07-16
- 摘要：A scheme for self-embedding an image into itself is proposed as a means for detecting and locating tamper,and self-recovering.The image is divided into small 8×8 blocks and each block is DCT transformed.A specified number of the lower frequency DCT coefficients are quantized and encoded using a fixed number of bits.The number of coefficients and their bit lengths are carefully chosen,according to the statistical property of these coefficients,the resulting bit-string for each block satisfies the payload of each block and has good self-recovering capability.The information about one block B (the bit string) is inserted into the LSB of another distant block,which is separated from B with an offset.We analyzed the method for choosing the offset.The proposed scheme is an one way watermarking and secure algorithm,and can well resist possible forged attack.关键词：multimedia authentication;digital watermarking;RSA public key encryption;self-embedding2|1272|29更新时间：2025-07-16
- 摘要：This paper studies an important problem in Connectivity Theory——augmenting a directed tree graph to a K-Vertex-Connected graph by adding a minimum set of edges and proves that this problem is P-Problem.An effective algorithm DTKA with complexity of is given.This algorithm contributes a foundation to the Computer Aided Design of reliable communication networks.关键词：directed tree;minimum augmentation;K-connectivity2|916|0更新时间：2025-07-16
- 摘要：With the popularization of embedded systems,low power design has become one of the most challenging tasks in the embedded system development.This paper presents a novel two-level power estimation model operating at the system-level,which including a microarchitecture level model to support hardware optimization and an instruction level model to support software compiling optimization.The microarchitecture level model based upon the information of components structure.The instruction level model based upon the microarchitecture model.Thus the proposed methodology provides an accurate and rapid model to evaluate embedded system high level design.关键词：embedded system;low power optimization;system-level power model2|1694|5更新时间：2025-07-16
- 摘要：Satisfactory results have been acquired in functional and combinational optimization by adopting particle swarm optimization.Its significant feature is simpler expression,less parameters and easier operation.However,selection of key parameters has great influence on algorithm effects.So the variance analysis of statistic theory is applied to analyze the effect of inertia weight and accelerating constants.It was proved that robust and effective optimization can be achieved by setting parameters according to the variance analysis results discussed.关键词：swarm optimization;parameter efficiency;statistic analysis2|1348|26更新时间：2025-07-16
- 摘要：We present a packet loss control scheme for IP networks-Dynamic Partial Buffer Sharing (DPBS).Compared with Static Partial Buffer Sharing (SPBS),the new scheme adjusts control thresholds dynamically according to packets loss behavior,which is endowed with better adaptability to changing network traffic.Also,DPBS avoids complicated threshold-setting problem:arbitrary initial value will never degrade system steady-state performance.Simulation results show that,DPBS can assure nearly fixed relative loss ratio,and its loss jitter performance is also better than SPBS under same traffic condition.关键词：buffer management;priority packet discarding;partial buffer sharing2|827|0更新时间：2025-07-16
- 摘要：Channel estimation using the parallel pilot channel in cdma2000 systems was investigated.The fractal theory was applied to describe multipath fading channels,and a novel channel estimation scheme using fractal filter in the sense of minimum mean square error (MMSE) was presented.It is demonstrated by computer simulations that the proposed method can estimate the channel parameters more accurately and track the changes of channel conditions self-adaptively in both rapid and slow terminal moving cases.The performance of the Rake receiver is improved notably.The results also show that the fractal model can describe multipath fading more effectively compared to the conventional statistical models.关键词：channel estimation;fractal filter;multipath fading;CDMA2000;fractal;mobile communications2|932|2更新时间：2025-07-16
- 摘要：In order to overcome fading in optical wireless channel,such as attenuation and scintillation,this paper introduces the adaptive rate compatible punctured turbo-coded ARQ scheme in optical wireless communication based on analysis of puncturing patterns.Simulations show that the adaptive error control scheme improves the throughput and stability of optical wireless link.Moreover,this paper proposes the rank retransmitting protocol to further improve throughput efficiency under adverse channel conditions according to optical wireless channel characteristic.关键词：optical wireless communication;Turbo code;hybrid ARQ;rank retransmitting2|956|2更新时间：2025-07-16
- 摘要：Classical Self-Organizing Maps presented by T.Kohonen is performed in the input sample space based on the Euclidean norm.It fails as the distrubution of input patterns becomes highly nonlinear.Kernel means,performing a nonlinear data transformation into some high dimensional feature space,increases the probability of the linear separability of the patterns within the feature space.Donald and others map the data in input space into a high-dimension feature space,where SOM algorithm are performed.However,its disadvantage lies in lack of direct descriptions about the clustering's center and result.In this paper,a novel kernel-based SOM algorithm is proposed.we replace the Euclidean norm in the SOM training procedure with kernels,which is equivalent to change the metric of distance in input space.Multiformity of kernels leads to different metrics of distance in input space ,and correspondingly results in SOM classifications.Finally we discuss the robustness and reliablity of KSOM by experimenting on Benchmark based on several classical kernel functions.关键词：SOM;kernel method;classification2|1411|9更新时间：2025-07-16
- 摘要：Filter function is the key point of CT convolution backprojection.This paper suggests a new filter function and gives the estimates of CBP,and the analysis of the time-frequency character.By the filter,Local tomography is implemented.The reconstruction results of simulation and experimental projection data show that this filter can improve Gibbs effects without decreasing the resolution of the images.关键词：convolution backprojection algorithm (CBP);new filter;error estimation;time-frequency character;local tomography2|1317|4更新时间：2025-07-16
- 摘要：Using the subthreshold MOS transistors,a low power current-mode multiplier is given in the paper.By adopting the multiplier as the kernel circuit,some modules used to compute the probability are designed.On the bases of these modules and the MAP algorithm,a soft-decision probability decoder of the (5,2,3) trellis code is implemented,and a novel pipelining serial input interface for the decoder is proposed.To verify the performance,the decoder is simulated with the model of standard 0.6μm CMOS process.关键词：analog multiplier;maximum a posteriori probability(MAP)algorithm;soft-decision decoding;trellis code;probability decoder2|858|0更新时间：2025-07-16
- 摘要：A Bloom Filter is a simple space-efficient randomized data structure for representing a set in order to support membership queries,which uses an m-bit array to represent a data set and queries by hashing.The representation is the payoff for allowing a small rate of false positives in membership queries;that is,queries might wrongly regard an element as member of the set.However,for many applications,especially large-scale data set systems,the space savings and the locate time constantly outweigh this drawback when the probability of an error is sufficiently low and can suffer from by the application.The paper firstly surveys Bloom Filter and its variants in detail,and gives mathematical analysis behind them about space/time/error rate tradeoffs in order to explain their practicability.Then,we present a new kind of Bloom Filter-Split Bloom Filter,which uses a s×m-bit matrix to represent a set,and give analysis in detail as the formers.In distributed systems,each network node owns a data set,which is reasonable that some nodes are large number of data while the large number of nodes are a bit of data,if all nodes uses same parameters of algorithm,then it will give rise to a memory space wholly wasted.In addition,if the number of the elements of a node date set increases continually,the error rate will increasingly make the representation nonsensically.We prove that the Split Bloom Filter can efficiently solve or weaken the two problems.关键词：bloom filters;distributed system;hash locating2|1605|12更新时间：2025-07-16
- 摘要：Network simulation is widely used in network research to evaluate the performance of network protocols.With the development of computer networks,network models grow in size and complexity,so execution time of simulation can be unbearably long.A parallel network simulator which runs on network of workstations is presented,the parallel network simulator is designed based on the popular sequential network simulator ns.Parallel discrete event simulation (PDES) techniques are applied to modify the event scheduling mechanism in ns.Some necessary extensions are also made to ns model library.Performance measures including speedup and memory consumption are evaluated at last.关键词：network simulation;parallel discrete event simulation;ns2|1521|7更新时间：2025-07-16
- 摘要：The criticism on the usage of Bayesian networks in expert systems is centered around the claim that the use of probabilitity requires a massive amount of data in the form of conditional probabilities.This paper shows that with given information easily obtained from experts,the dependence model probabilities can be estimated using backpropagation,such that during training the Bayesian characteristic of the network is preserved .Applying the Occam's razor principle results in defining a partial order among neural network structures.Experiments show that for the Multiplexer problem,the network compiled from the more succinct causal model is better than the one compiled from the less succinct model.关键词：bayesian networks;SIGMA-PI networks;propagation networks2|735|0更新时间：2025-07-16
- 摘要：We present a new lightpath establishment protocol CLEP (Compound Lightpath Establishment Protocol) for wavelength routed all optical networks.By using a compound lightpath establishment mechanism,as apposed to simple forward reservation by CR-LDP and backward reservation by RSVP-TE,CLEP outperforms both of them significantly in terms of connection blocking probability,lightpath setup delay,computational complexity and control message overhead.关键词：all optical networks;signaling protocols;lightpath;network simulation2|981|1更新时间：2025-07-16
- 摘要：This paper studies the phenomena of intermittent subharmonics and chaos in DC-DC converters according to the consideration of coupling filter,consequently concludes that the origin of intermittency comes from conducted or radiated EMI.By constructing a circuit model of switching converter coupled with spurious signal,simulation can gain the same results as those from experiment.Furthermore the paper discusses the different effect on intermittency induced by different sets of parameters,thus provides the design consideration of reliability.The same research method can also be used to study the intermittency in other types of nonlinear circuits and systems.关键词：switching power converters;spurious signal coupling;bifurcation;chaos;subharmonics;intermittency2|1099|5更新时间：2025-07-16
- 摘要：Let V be the space of dimension n over GF(2),f(x) a boolean function on V.In this paper,the set U of the vectors satisfying the propagation criteria is discussed.If deg f(x)=n,then U is an empty set.For all the functions of degree 2,U have at least half vectors of V.The avalanche characteristics of a class of functions is discussed.Boolean functions have no nonezero linear structure if and only if there are n linear independence vectors.Furthermore a construction of functions which satisfy propagation criteria of degree 2 is given.关键词：boolean function;propagation criteria;linear structure;linear subspace2|871|1更新时间：2025-07-16
- 摘要：Time management service is one of the main features which distinguish HLA from previous distributed interactive simulation standards,and is the most important and difficult part in RTI implementation.Its implementation method can affect the efficiency and validity of simulation directly.The key problem of the implementation of time management service is the computation of Greatest Available Logical Time (GALT).Aiming at the possible deadlock problem of the current GALT algorithm,an optimized algorithm called recursive GALT (R-GALT) algorithm along with the idea of recursive advancing check is proposed.A formalized verification is also presented.Compared with the original algorithm,the new algorithm can not only enhance the efficiency,but also avoid deadlock.The algorithm has been used in the design of RTI software StarLink which is based on CORBA and in accord with IEEE 1516.The measurement shows that the performance of time management of StarLink is better than of pRTI1516 (it's supposed to be the best RTI product in the world).关键词：high level architecture;runtime infrastructure;time management;greatest available logical time2|1413|5更新时间：2025-07-16
- 摘要：It is a new attempt to apply the case based reasoning(CBR) method to the pattern CAD domain.This paper presents a case based model for pattern design.We first decompose the pattern into pattern elements,and represents the pattern case by frame-based case structure and element-based case data,then the procedure of pattern design is modeled as the case-making process of specific pattern case frame aiming to various pattern elements.We also present some new solving strategy for the key techniques used in CBR,such as the organization and query mechanics of case base,case adoption and re-design of case etc.Meanwhile,the conductive interaction technique based on design context and the knowledge-based promotion from local operation to global layout are applied successfully in the model.Running the prototype system shows that CBR is an effective approach for the design of serial and regular pattern.关键词：pattern design;CBR;conductive interaction technique;knowledge-based promotion2|954|0更新时间：2025-07-16
- 摘要：A new model based on deterministic annealing for detecting intruders/users masquerading as other users is presented.In our model,each user is viewed as a discrete stationary source with variable memory.A sequence of characters composed of command lines from a user's account is regarded as the result that is potentially generated by the user and the intruder in different period.We determine masquerades by finding the source(s) in the sequence.Our experiment shows that the model is feasible.关键词：network security;intrusion detection system;rate distortion theory;deterministic annealing2|935|0更新时间：2025-07-16
- 摘要：Internet routing control by link weights optimization with traffic engineering objectives is studied.It is modeled as a mathematical programming problem with the objectives of network congestion minimization and delay minimization.It is a NP-hard problem,and a chaotic group search algorithm based on local search is proposed,which makes use of chaos variable to find initial solutions with favorable distribution,and applies extended greedy principle to local search process to increase global search ability.Simulation results manifest that it improves network performance with decreased congestion probability caused by unbalanced traffic distribution,and restricted extra path hops.关键词：traffic engineering;routing;congestion;delay;local search2|1023|6更新时间：2025-07-16
- 摘要：A new priority table based real-time scheduling algorithm named DVDF (Deadline-Value Density First) is proposed.This algorithm takes the deadlines and value density of real-time tasks into account synthetically,and can adapt different load conditions better.In contrast to classical EDF (Earliest Deadline First) algorithm that only considers the deadlines of real-time tasks,DVDF algorithm is shown to improve the performance of scheduling obviously by simulation with some typical data of various parameters under normal workload and overload situation,especially under overload situation,it can degrade gracefully.关键词：real-time scheduling;priority;hit value ratio;weighted guarantee ratio;differentiated guarantee ratio2|1474|6更新时间：2025-07-16
- 摘要：The paper presents a variant gray-scale histogram (VGH) for the purpose of detecting and locating captions in video images.The definition of VGH is given and the mapping relationships are analyzed between features in VGH and captions in an image.Then,we proposed an algorithm for detecting and locating captions in an image by recognizing the features,including both valleys in row-based VGH of a vertical sub-image and convexes in column-based VGH of a horizontal sub-image.Some experimental results are given in the end of the paper showing validity of the algorithm.关键词：gray-scale histogram;variant gray-scale histogram;video image;caption detection and location2|1221|5更新时间：2025-07-16
- 摘要：Rectangular fault block model is designated to solve the problem of fault-tolerant route in mesh and was improved as Minimal-Connected-Component (MCC) model.Based on MCC,we construct an overlapping graph and give a set of algorithm according to the graph to work out the route as short as possible to avoid the appearance of fault block when Manhattan route does not exist.The simulated test shows that the route found by the algorithm mentioned above is nearly the shortest one.Hence compared to other methods costing much more time,this new heuristic fault-tolerant algorithm is of no doubt a better method in finding the shortest route.关键词：adaptive routing;fault block model;fault tolerance;mesh2|836|3更新时间：2025-07-16
- 摘要：A 12-channel vertical-cavity-surface-emitting laser (VCSEL) array driver chip has been realized in a 0.25μm CMOS technology.The maximum output modulation current of a single channel is over 30 mA.Experimental results show that a single channel has a speed of 3.125Gb/s and a total capacity of 37.5Gb/s can be obtained from 12 channels.关键词：VSR;VCSEL;CMOS;laser driver2|1150|1更新时间：2025-07-16
- 摘要：Based on LK algorithm,a distributed mutual exclusion algorithm—read/write mutual exclusion (RWME) algorithm is presented.It puts different mutual exclusion operations for reading request and writing request.The algorithm belongs to nontoken-based type.It saves the message complexity and still has T synchronization delay.A read/write globe clock stamp which based on Lamport clock stamp is defined for the read/write mutual operations.Using the read/write globe clock stamp,reading and writing requests can access critical sections with fairness and freedom from deadlock or starvation.Proved by performance analysis,the algorithm has high-performance.A correctness proof is provided.关键词：RWME algorithm;distributed mutual exclusion;read/write clock stamp;message complexity2|954|9更新时间：2025-07-16
- 摘要：A novel rate-based multicast congestion control scheme—RBMCC is presented,which uses the positive explicit congestion indication and proxy-based feedback control scheme to inform the sender about the status of network,so that the sender can detect incipient congestion early and adjust the send rate to alleviate congestion by changing packet intervals.The mechanism was implemented in the Network Simulator and its performance was compared with other algorithms by simulation.The simulation results show that RBMCC improves the dynamics and responsiveness,uses the available resource of network efficiently,and also has good TCP-friendliness.关键词：multicast;congestion control;TCP-friendly;RBMCC2|1144|1更新时间：2025-07-16
- 摘要：The equivalent source theory based on lossy transmission line model is used to analyze the interconnect effect for propagating signal integrity in clock circuit which is operated at GHz frequency.Simultaneously three-port network is brought to the "T" structure in clock tree, the result shows this is an efficient method to analyze the signal integrity in clock tree.关键词：interconnect;signal integrity;equivalent source theory2|1005|0更新时间：2025-07-16
- 摘要：The existing adaptive lattice notch filter whose regressor is got from local error signal has a bias of the notch frequency after convergence of iterative procedure,and the effectiveness of filtering is not desired.This paper discusses about adaptive algorithm of cascaded lattice notch filter.Analyzing the relationship between coefficients estimated and regressor,a modified adaptive algorithm is proposed according to the deduced expectation equation of iterative error.Without additional computation,this algorithm has a reduced bias in the estimation of notch frequency,which is exhibited in former algorithms.Simulation results confirm the theoretical analysis and demonstrate the convergence of the algorithm is better than that of former algorithms.关键词：lattice filter;adaptive algorithm;convergence2|1087|12更新时间：2025-07-16
- 摘要：The domain decomposition method,when combined with flexible decomposition and load-balancing strategies,can improve the parallel performance of iterative computations and save the costs in large-scale numerical reservoir simulations.However,the ordinary domain decomposition method was found to have problems of increased computational load and slowed convergence,especially in working with non-uniform domain numerical simulations.Here,we report the results of an efficient parallel approach that we have recently designed and implemented.This approach used preconditioned domain decomposition method and load-balancing strategy based on the distributed parallel environment to reduce the computational complexity of non-uniform numerical reservoir simulations and enhance the computational speed.Our computational results showed that the simulation speed was improved largely with a high speedup.关键词：numerical simulation of reservoir;parallel computing;domain decomposition;load-balancing2|1232|1更新时间：2025-07-16
- Technical support is provided by Beijing Founder electronics co., LTD 京ICP备09064830号-19
京公网安备11010802024621 - It is recommended to read the content of this site in Chrome&IE9+. Please switch to extreme mode in browser 360.
- Cookies We use cookies to help provide and enhance our service and tailor content. By continuing, you agree to the use of cookies.
0