最新刊期
卷 30 ， 期 11 ， 2002
- 摘要：In this paper the four sets of standard processes developed by Institute of microelectronics of Peking University are presented.In these four sets of standard process,three of them are bulk micromachining processes and one is surface sacrificial process.The key technologies used in these processes were studied systematically.Research work included:systematically study how to control the stress of polysilicon film;developed two anti-stiction technologies;research of Si/Si bonding,Si/Ni/Si bonding and Si/Glass bonding;study and optimization of high aspect ratio silicon etching;successfully reducing RIE Lag from 23% to 5%;exploiting two kinds of multi-step silicon etching technologies.关键词：MEMS standard process;high aspect ratio;bonding;polysilicon;stress;anti-stiction2|3798|23更新时间：2025-07-16
- 摘要：A new kind of piezoelectric transformer,radial vibration mode piezoelectric transformer,is investigated through linear piezoelectric equations combined with the theory of elasticity,and its equivalent circuit model is deduced.According to the model,the mathematical expressions of the input impedance,output impedance,voltage gain,output power and efficiency of radial vibration mode piezoelectric transformer are concluded.These expressions are verified by the experiment results.关键词：piezoelectric transformer;radial vibration;equivalent circuit2|2348|9更新时间：2025-07-16
- 摘要：An extension of the equivalent small parameter symbolic method to constant-frequency current-mode controlled converter systems is presented,along with two methods of determining the system's duty-ratio,the precise and the simple methods .It is shown that the former is practical due to its having no assumptions of linear inductor current waveforms and small output ripples,and the latter is useful for simplified engineering analysis.The resulted analytical expressions are helpful to understand the mechanism of the circuit.关键词：current-mode control;switching power converter;closed-loop systems;symbolic analysis2|753|0更新时间：2025-07-16
- 摘要：With the development of the VLSI circuits,the feature size has been decreased to the deep sub-micron level,andworking frequency has reached to 2GHz. In order to assure the correctness of the IC design with high performance,the parasitic interconnect inductance and resistance should be calculated quickly and accurately.In this paper,we propose a description format to fit for 3-D hierarchical interconnect,an approach to automatically partitioning filaments in consideration of skin effect.An improved multipole accelerative computation based on the non-uniform cube subdivision is implemented.Numerical results show that it runs faster than the FastHenry[1] from several to several tens' times with comparable accuracy.关键词：VLSI;parasitic inductance;PEEC;skin effect;multipole acceleration2|1026|0更新时间：2025-07-16
- 摘要：The factors which determine the quality (Q) factor of planar spiral inductor are presented in this paper,and a technology to fabricate suspended MEMS devices for RF circuits is presented.A simplified electrical model is used to study the influence of high-frequency magnetic fields on the parasitical resistance,including the eddy effect and skin effect.To get high-Q suspended inductor,porous silicon (PS) is used as sacrificial layer,and SiO2 film is used as a support membrane.During the process,TMAH solution with Si powder and (NH4)2S2O8 is used to remove the PS layer through small etching holes with no influence on the uncovered Al in the devices.A suspended inductor structure is realized using this technology. The fabrication is proved to be reliable.关键词：MEMS;inductor;quality (Q) factor;porous silicon;sacrificial layer3|1049|0更新时间：2025-07-16
- 摘要：A closed-form model able to predict high frequency thermal noise of SOI MOSFETS for all channel length down to deep sub-micron in saturation region has been presented. By incorporating the energy balance equation, this model can exactly describe the noise behavior of SOI MOSFET.At the same time, the phenomena that a deep sub-micron MOSFET exhibits a minimum noise value at a certain drain current (Iopt) when working in saturation can be explained very well. This model has been verified by experimental data and can be easily implemented into existing circuit simulators such as SPICE.关键词：modeling;SOI MOSFET;high frequency noise2|1056|0更新时间：2025-07-16
- 摘要：A novel structure,which is implemented by anti-doped silicon island to realize fully depletion in thick film SOI MOSFET,is proposed in this paper and the relationship between its performance and structure key parameters is analyzed.The thick film SOI MOSFET can be fully depleted under normal operating condition,if there is an anti-doped silicon island near the back gate in the channel.Two-dimensional(2-D)numerical simulations have proved that through some optimizations of the width,the height,the doping concentration and the position in the channel of the anti-doped silicon island,thick film SOI MOSFET can achieve fully depleted channel which means no KINK effects,and more driving current resulting in high speed,while it suppresses the SCEs effectively.The simulation results show that:optimized anti-doped silicon island should be positioned in the center of the channel near the back gate,and its width is three fifth of the channel length with height half of the thickness of silicon film,while its doping concentration keeps higher than that of the substrate.Most importantly,this novel structure shows excellent tolerance of the fluctuation of the width,height,position and doping concentration.It can be seen that this thick-film FD SOI MOSFET will be one of the promising structures in design of thick film SOI MOSFET devices.关键词：anti-doped silicon island;thick film fully depleted SOI;Kink effect3|1308|0更新时间：2025-07-16
- 摘要：The new still image compression standard JPEG2000 adopted Discrete Wavelet Transform(DWT)as the key transform technology and recommended to implement it with lifting algorithm.Spatial Combinative Lifting Algorithm (SCLA) based 2-D DWT with 9/7 filter requires 7/12 amount of computation the conventional lifting based implementation.This paper proposes a novel VLSI architecture to compute multilevel SCLA based 2-D DWT with 9/7 filter,which greatly speeds up the transform process and achieves higher hardware utilization.This architecture can be used as a compact and efficient core for JPEG2000 VLSI implementation and various real-time image/video applications.关键词：discrete wavelet transform(DWT);JPEG2000;lifting;spatial combinative lifting algorithm(SCLA)2|1024|3更新时间：2025-07-16
- 摘要：To support the retrieval by example,audio multimedis database ought to be capable of automatically analyzing audio data for producing the index of the audio data.We combined the index method based on discrete wavelet transform with the method based on time-frequency analysis in this paper.And a method was proposed that utilize the wavelet subband,a certainly proportional high-frequency coefficient of the wavelet subband and all the approximately coefficient etc.to form the index vector.The proposed method introduced double index search,that is using zero-cross vector and average magnitude vector at first pre-search and then using key coefficient of the wavelet transform as index to make more detailed search.The experiment shows that this method has a high retrieval precision and search efficiency,and has importance sense in the audio multimedis database based on example index and search.关键词：wavelet transform;time-frequency analysis;key coefficient;zero cross rate;average magnitude2|765|0更新时间：2025-07-16
- 摘要：Data type conversion in distributed heterogeneous system is all along an important problem related to the computer and automatic domain.In electric power system,there wasn't any successful application that use CORBA in such a conversion in our country.This paper presents that CORBA can be used in electric power system,and further,it presents a new concept of data type discriminator.These two ideas above are feasible with the solution of the problem of a general query about the database in a distributed heterogeneous system of an electric control centre.关键词：distributed system;data type discriminator;general query about database;CORBA2|667|0更新时间：2025-07-16
- 摘要：Stochastic Petri Net (SPN) are a powerful modeling and analyzing tool for system performance evaluation.But the problem of state space's explosion of SPN limits its ability to analyze complex and large-scale systems.So it is more feasible to simplify SPN model on the basis of performance equivalence before analyzing it.In this paper,the authors define a class of SPN-Elementary SPN (ESPN) which is composed of four elementary subnets including sequence subnet,parallel subnet,choice subnet and iteration subnet,and propose a group of performance equivalence formulas for the four elementary subnets,as well as a method of performance equivalence simplification and analysis for ESPN with linear time complexity.In addition,two transforming rules are put forward to transform non-elementary subnets into combined elementary subnets such that the proposed algorithm can be used in analysis of more general SPN.关键词：stochastic Petri nets;elementary stochastic Petri nets;performance equivalence;performance analysis2|1707|12更新时间：2025-07-16
- 摘要：Today workflow technology is a hot research topic and workflow models should support adaptation and be able to model large-scale and complex systems in order to be widely applied.We first put forward using Process Algebra(PA)-Communication Sequential Process(CSP) to model workflow systems and solve the adaptation of the models.The composition property of PA can be used to construct complex systems from simple systems,so it can solve the difficult problem to model complex systems and support the reusability of workflow models.关键词：process algebra;adaptive workflow;consistency;soundness2|1627|4更新时间：2025-07-16
- 摘要：Employ the model of closed network,decompose the circuit by opening,shorting and coloring some edges auording to the element parameters,one tier by one tier,then a graph called the Network Expansion Diagram (NED) is built up.The concept and rules of NED are given.It is pointed out that the value of every path in NED just is one valid term of the expanded network determinant.Then the symbolic network functions can be obtained from NED.This method handles directly circuits by graph operations.It is applicable for generating all types of network functions to general active circuits.关键词：symbolic network analysis;network functions;network graph theory;the network expanding diagram;colored edges2|911|0更新时间：2025-07-16
- 摘要：Traffic behavior in a large-scale network is very perplexing and can be viewed as a complicated non-linear system.So far the research on traffic behavior doesn't have a well-rounded method.According to the character of non-linear network traffic,the traffic time series is decomposed into trend component,period component,mutation component and random component.With such decomposition,a complicated traffic can be simulated by compound of four simpler sub-series with different mathematical tools.In order to check our model,the long-term traffic behavior of the CERNET backbone network and NSFNET backbone network are analyzed using the decomposed model,and the results are compared with ARIMA model.According to the autocorrelation function value and prediction error function value,the decomposed model has the advantage of simplicity and high precision to describe the traffic marco-behavior.关键词：non-linearity;traffic macro-behavior;decomposed model2|1455|3更新时间：2025-07-16
- 摘要：Different Shared Risk Link Groups(SRLG)identifiers can be assigned to each link by network administrator in optical Traffic Engineering(TE)with GMPLS to satisfy connection's reliability requirement.A dependable connection can be achieved by establishing two SRLG-disjoint paths.A new routing algorithm for shared path-protection based on SRLG-disjoint is presented in this paper.It provides the same level of protection against single SRLG failure as dedicated path-protection scheme.Moreover it is superior to dedicated path-protection scheme in network utilization.Network performance, based on dynamic traffic with different load,is investigated via simulations.The results show that the scheme can improve the performance of the network significantly.关键词：generalized multi-protocol label switching (GMPLS);shared risk link groups (SRLG);shared path-protection;dynamic routing and wavelength assignment(RWA)2|1018|8更新时间：2025-07-16
- 摘要：In heterogeneous cluster environment,the network topology is irregular,and performance gap exists among computer nodes and among interconnected networks.These factors affect the performance of collective communication.To solve this problem,we present MGO (Multi-Granularity Optimization) algorithm.In MGO algorithm,we optimize the path for collective communication by network topology and the performance of the computer nodes and the networks.The simulation results show that by comparing MGO algorithm with related optimized algorithm,the former can result in notable performance improvement.Moreover,the performance-enhancing ratio increases to some extent as the cluster scales up.关键词：collective communication;cluster;topology;message passing2|772|0更新时间：2025-07-16
- 摘要：To numerically simulate bistatic scattering from fractal rough dielectric surface at low grazing angle (LGA),a hybrid approach of the forward-backward method (FBM) with spectral accelerate algorithm (SAA) is developed.The impedance matrix of the electric or magnetic field integral equations is decomposed into four sub-matrices for fast FBM algorithm.Bistatic scattering from and transmitting through one-dimensional (1-D) fractal rough surface with any dielectric constant are calculated.Angular reflectivity and transmitivity demonstrate the energy conservation,and its functional dependencies upon the surface parameters are discussed.A linear relationship between the envelope slope of the bistatic scattering pattern and the fractal dimension is also discussed.关键词：bistatic scattering;transmitting;FBM/SAA;fractal rough surface2|1059|7更新时间：2025-07-16
- 摘要：The selection of secure elliptic curves and the scalar multiplications of elliptic curves are two important problems in the practice of efficiently implementing an elliptic curve cryptosystems.In this paper,we study those two problems jointly,give a class of secure elliptic curves mainly based on the computer words,describe a detailed process of how to selecting those curves,and present a new method,which is based on the idea of "baby step-giant step",of computing the scalar multiplication concerning those curves.With the new method,the amount of scalar multiplications based on those curves can be reduced greatly. Besides,when those curves are used,special representation method for the elements in the base field is no longer needed,and all the arithmetic in the field can be quickly accomplished.关键词：elliptic curve cryptosystem;secure elliptic curves;scalar multiplication;Frobenius expansions2|1108|3更新时间：2025-07-16
- 摘要：Chinese Wall security policy (CWSP) is one of the most important security policies in commercial information area.But the CWSP proposed by Brewer and Nash can't fully meet the practical requirement.The role-based access control (RBAC),a policy neutral model,has recently received considerable attention as a most promising alternative to traditional discretionary access control (DAC) and mandatory access control (MAC) models.RBAC and the Chinese Wall security policies are given,and expanded due to the practical application.The RBAC-based method to expand CWSP is systematically discussed.Thus,the enhanced CWSP (ECWSP) is presented firstly.And then the method of configuring RBAC to enforce the ECWSP is systematically studied.关键词：information security;role;role-based access control;enhanced Chinese Wall security policy2|952|0更新时间：2025-07-16
- 摘要：A model of synchronous chaotic coupling system for optical fiber chaotic secure communication is presented.A system with distributed feedback semiconductor lasers with external light injection of 1.31μm bas been successfully stimulated in long distance fiber.The synchronization is limited by the intercross-phase modulation in the fiber.The propagation limit is presented.Both analong and digital optical fiber chaotic secure communications with the system are studied by numerical simulations in the long propagating distances.The system shows a good ability of robust security and anti-code-breaking.Optical fiber chaotic secure communications can be realized.关键词：chaos;synchronization;optical fiber chaotic secure communications2|1040|5更新时间：2025-07-16
- 摘要：YH TS-1 is a 32-bit embedded microprocessor designed by School of Computer in National University of Defense Technology.It is a top-down design and has fully intellectual property.YH TS-1 has a RISC core,six-stage pipeline,separated data Cache and Instruction Cache.Specially,YH TS-1 has dynamic instruction schedule with two instruction fetch units,vector processing mechanism towards embedded application,content copy/switch based register window interrupt processing mechanism,and support of the open WISHBONE IP interface specification.This paper will mainly describe the YH TS-1 RISC core design methodology and its critical implementation technologies.The experimental results will also be given at the end of the paper.TS-1 has been implemented and verified in Altera's FPGA EP20K400EBC,and the clock frequency can be 36.7MHz.关键词：embedded microprocessor;architecture;vectorization;pipeline;RISC2|876|0更新时间：2025-07-16
- 摘要：The exponential stability of stochastic cellular neural networks with delay was investigated.For such neural networks,we establish two types of sufficient conditions for the exponential stability in the mean square and surely exponential stability.One type involves delay independent results while the other type involves delay dependent results.关键词：cellular neural network;exponential stability;lyapunov functional;Lyapunov function2|1076|4更新时间：2025-07-16
- 摘要：Routers must perform packet classification at high speeds to support advanced functions such as firewalls and QoS routing.While several efficient solutions are known for the one-dimensional IP lookup problem,the mult-dimensional packet classification has proved to be far more difficult.Existing filter schemes with fast lookup time do not scale to large filter database.Based on tuple space search,a packet classification algorithm called bitmap vector of tuple space for multi-dimensional conflict-free filters is presented in this paper.The result of the performance analysis in two-dimension and multi-dimension shows that the scheme provides better worse case bounds about time and space complexity than what have existed,so the algorithm is more scalable and faster.The novel approach can be easily implemented both from software and hardware which made this algorithm more practical to application.关键词：conflict-free packet filters;classification;tuple space;bitmap2|826|3更新时间：2025-07-16
- 摘要：Enterprise computing focuses on seamless integration of critical applications under distributed and heterogeneous environments.Traditional enterprise computing models are "top-down" ones that are inconsistent with "bottom-up" interoperation requirements.This paper brings forward a novel model named UECM for enterprise computing which is based on the coordination of loose-coupled messages and peer-to-peer technology.It aims to provide a light-weighted,low-cost,robust and scalable infrastructure for interoperations among enterprise applications under heterogeneous,distributed and decentralized environment and better solve the problems of extensibility and server bottle-neck caused by traditional models.关键词：information island;interoperation;peer-to-peer computing;peer;service;message;UECM2|690|0更新时间：2025-07-16
- 摘要：Modeling and simulation of multi-body system dynamics is a difficulty in mechatronics integrated designing environment.Traditionally through multi-body domain-specific software packet,the DAEs is generated,which is then converted to the uniform modeling language and embedded in the integrated environment.Based on port-based modeling paradigm,this paper constructs the Multi-Ports Component model for multi-body system dynamics,and detailed component behavior model is given adopting VHDL-AMS uniform modeling language.At the end,an example is used to demonstrate the main ideas.关键词：mechatronics;multi-body system;port;VHDL-AMS2|1189|0更新时间：2025-07-16
- 摘要：A new convertible designated confirmer signature based on elliptic curve is presented.The new scheme not only can resist all forgery attacks,but also has the properties of convertibility and retraction.The convertibility is that the designated confirmer signature can be converted into general signature if needed.The retraction is that the original signer can retract the right of the designated confirmer's signature verification if needed.The new scheme is constructed based on elliptic curve,therefore the scheme is possessed of the merits of higher security,higher efficiency,smaller key,and very simplicity etc.关键词：designated confirmer signature;forgery attacks;elliptic curve2|867|1更新时间：2025-07-16
- 摘要：Based on Capacity Rule and Block Partitioning (BP) strategy,a robust Multilevel Coding (MLC) scheme is proposed for AWGN and Rayleigh fading Channels using punctured convolutional codes.The system performance is compared with that of the uncoded 4ASK system and the MLC with BCH codes.The formulations for computing the soft decision metrics with Channel State Information (CSI) are presented for multistage decoding (MSD) and the performance comparisons are made for soft and hard decision decoding.The research can present some references for the optimal design of Multilevel Coding schemes.2|745|1更新时间：2025-07-16
- 摘要：The protection designing issue for the optical network consisting of the two-level optical cross-connect node is investigated in this paper.The protection capacities programming model is built and simulated.The simulation result shows that the protection performance severely depends on the optimization function of the model and the assignment policy of network capacities.关键词：optical network;multiple granularities cross-connect;protection programming model;protection performance2|765|1更新时间：2025-07-16
- 摘要：A novel laser diodes' driver was introduced.Using only 4 discrete NPN double polysilicon bipolar transistors and one conventional silicon bipolar transistor as active devices,the driver can provide 50 mA modulation current to drive laser diodes for a load of 25Ω and can provide 2.5 V modulation voltage to drive EA modulators for a load of 50Ω.The driver has the rise/fall time of less than 100 ps and can be used for bit rate up to 3 Gb/s with the modulation and the bias current of 5~50 mA respectively.关键词：LD driver;EAM driver;high bit rate modulation;bi-stable trigger2|795|0更新时间：2025-07-16
- 摘要：A novel capacitor mismatch calibration technique for pipelined analog-to-digital conversion is presented.The nonlinear capacitor mismatch error is reduced to the second order through an algorithmic circuit method,which involves charge summing,capacitors exchange,and charge redistribution.Simulation results confirm the observation and a case of 12-bit INL realized by 4-bit capacitor matching is shown.Compared to the conventional circuit,the new approach is still a simple implementation by requiring only some extra analog switches.On the other hand,the conversion speed is slowed because one conversion now requires three clock phases instead of two.Therefore this technique is most suitable when moderately high speed combined with high resolution is required.关键词：capacitors exchange;capacitor mismatch calibration;pipelined A/D conversion;circuit techniques2|1095|1更新时间：2025-07-16
- 摘要：Yield and reliability are two problems that are focused on semiconductor manufacturing.The researched results show that there exists a relation between yield and reliability of IC's.In order to describe this correlativity,the yield critical area and the reliability critical area are analyzed based on the mechanism of open circuit of interconnections caused by manufacturing defects,and the model of relation between IC's yield and reliability is presented in this paper.Finally,the validity of this model is shown by computer simulation.关键词：yield;reliability;critical area2|747|0更新时间：2025-07-16
- 摘要：The open-short-load(OSL)method is very simple and widely used for one-port test fixture calibration.In this paper,this method is extended to the calibration of two-port test fixtures for the first time.The problem of phase uncertainty arising in this application has been solved.The comparison between our results and those obtained with the short-open-load-thru(SOLT)method shows that the method established is accurate enough for practical applications.关键词：calibration;microwave network analyzer;scattering-parameter measurement;phase uncertainty2|1259|3更新时间：2025-07-16
- 摘要：By combining the strong tracking filtering theory with data fusion estimation technology,a new joint state and parameter estimation algorithm of multisensor based on strong tracking filter is proposed.For the multisensor and single model nonlinear dynamic systems having the same sample rates for every sensor,the fusion estimate on the basis of global information by use of strong tracking filter is established,and the effectiveness of the new algorithm is also illustrated by use of an example.These give a primary solution to the fusion estimation problem having bigger errors produced by Kalman filter because of uncertainties of modeling system.This work enriches and develops the information fusion theory.关键词：strong tracking filter;fusion estimation;fading factor;dynamic systems;Kalman filtering2|963|7更新时间：2025-07-16
- 摘要：Parallel programming paradigms to support multi-models in cluster and Grid environment,such as Master/Slave,Divide and Conquer,Phase Parallel and so forth this paper proposes a Master/Group/Slave programming model－JOGR with which we can realize data allocation and load-balance dynamically in cluster environment.Furthermore,based on WebService technology and Java language,we focus on the implementation of JOGR.Experimental results show that JOGR can provide effective support for developing and running parallel programs.关键词：webService;object group;cluster computing;grid computing;parallel programming paradigm2|767|0更新时间：2025-07-16
- 摘要：In the Automatic Fingerprint Identification System(AFIS),we face the fact how to effectively use the huge curve information of fingerprint to describe fingerprint.This article proposes a novel algorithm;it embraces information of few fingerprint ridges nearby to extract a new characteristic which can describe the curvature feature of fingerprint.Experimental results show the algorithm is feasible,and the characteristics extracted by it can clearly show the inner macroscopic curve properties of fingerprint image and can be used for fingerprint verification as a supplement to the customary minutiae.The result also shows that this kind of characteristic is robust to noise and pollution.关键词：fingerprint recognition;minutiae;feature extraction;curvature2|1206|1更新时间：2025-07-16
- 摘要：In order to cancel the reflecting echo of telephone speech interactive system,the telephone channel and line echo were studied.The channel impulse response is firstly estimated,and the convolution of channel impulse response and suggestive speech is calculated,which will be used to counteract the echo.The time delay between echo and primary signal is estimated and canceled using de-convolution or Cross-power Spectrum Phase method before the channel impulse response is estimated.This algorithm can get better echo canceling and primal speech fidelity than LMS adaptive filter.After Echo Cancellation,the speech recognition correction rate and accuracy rate are improved by about 29% and 60% respectively.关键词：telephone speech;echo cancellation;correlation;comb filter2|1372|3更新时间：2025-07-16
- 摘要：First the BER performance is analyzed given the channel statistics information.And the BER is calculated given the delayed channel states information under assumptions of different Doppler frequency.Based on the upper bound of channel prediction algorithms,we point out that developing good channel prediction algorthms is a potential direction.关键词：close loop transmit diversity;delayed feedback;channel prediction2|854|0更新时间：2025-07-16
- 摘要：An active queue management algorithm for flows called MBUE is proposed.It uses packet loss and link utilization history to indicate the congestion,and not relies on average queue length as an estimator of congestion.MBLUE detects incipient congestion,and notifies connections either by dropping packets or explicit congestion notification (ECN).It makes no assumptions about queuing architecture and will work with a FIFO queue.There is small amount of each flow maintained to achieve fair bandwidth allocation among flows sharing the bottle-neck connection.This algorithm removes biases against bursty sources,and gives protection to fragile flows.It can manage non-adaptive flows also.Using simulation and experiments of TCP and UDP traffic,MBLUE is shown to perform better than other algorithms on both fairness and packet loss rate.关键词：congestion control;flow;queue management2|833|2更新时间：2025-07-16
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