最新刊期
卷 32 ， 期 S1 ， 2004
- 摘要：A change of telecom service mode is analyzed and the environment and requirements that faced telecom high technology R&D (863) Program of China at beginning of new century is presented in this paper.The strategic deployment of Telecom Subject of 863 Program during 10th Five Year Plan is introduced.The progress and innovative reserach achievements on new generation information network,large capacity optic fiber transport network and beyond 3G mobile communications system are mostly summarized.关键词：communication;internet protocal;automatic switch optical network (ASON);beyond 3G2|1014|0更新时间：2025-07-16
- 摘要：This paper discusses key research topics of future mobile communications,analyzes specially technique bottleneck of high speed and efficiency transmission,revelation of high speed coding,obsession from cellular structure and wireless coverage,and harmonization of mobile networks,then points out technical challenge faced and revolutionary new method.关键词：future mobile communications;4G;high speed and efficiency techniques;mobile cellular structure;mobile network configuration and protocol2|1238|0更新时间：2025-07-16
- 摘要：The latest research advances of advanced optical network and its supporting technologies are reviewed.The current status of advanced optical network including high speed optical devices,optical node equipments,and optical networking technologies are introduced,and some key technologies of automatically switched optical network (ASON) are analyzed.Considering the evolution and development of ASON,some directions and hot spots in the later research are pointed out.关键词：advanced optical network;high-speed optical devices;optical node;optical networking;ASON2|1090|0更新时间：2025-07-16
- 摘要：Distributed radio and its application in cellular mobile communications system are investigated.Based on the analysis of evolution trends of mobile communications system and related key technologies,a novel generalized cell structure,radio resource management model and handover algorithm for future mobile communications system are proposed to meet the requirement of new technology applications like MIMO,multi-carrier,radio over fiber,mobile IP and higher working frequency.关键词：distributed radio;cellular mobile communications system;generalized cell structure;radio resource management model;handover algorithm2|3060|0更新时间：2025-07-16
- 摘要：Multicast is an important research topic for the Internet.Recent research shows some intrinsic limitation in IP Multicast,and Application Layer Multicast (ALM) is proposed.In this article we discuss and classify some major algorithms proposed for ALM.The fundamental problems in ALM research are identified and the metrics for evaluation of ALM algorithms are summarized.Some topics (e.g.,Overlay Network,media encoding method) are also discussed for their close relationship with ALM research.Finally,some possible directions for future research are discussed.关键词：multicast;application layer;overlay;internet2|3003|0更新时间：2025-07-16
- 摘要：The larger overhead of mobile IPv6 reduces the transmission efficiency of wireless networks.This paper presents a compression profile for mobile IPv6 based on the Robust Header Compression in order to increase the efficiency of wireless networks.The simulation performance is showed that the profile is efficient for mobile IPv6.The implementation of mobile IPv6 header compression in PDA is descr ibed.关键词：Mobile IPv6;header compression;wireless networks6|1239|0更新时间：2025-07-16
- 摘要：Mobile IPv6 is complicated and distributed,which makes it difficult to describe protcol and generate test sequences.The idea of hierarchy protocol description is proposed.Finite state machine (FSM) and multi-node finite state machine (MN-FSM) are defined.Mobile IPv6 protocol is divided into four layers.FSM and MN-FSM are used to describe protocol performing procedure,mobile IPv6 nodes,internal data structure management and discrete functions.The state goto graphes are changed into directed graph.Test generation algorithm for directed graph is designed and the set of test sequences covering mobile IPv6 is generated.关键词：Mobile IPv6;Conformance Testing;protocol description;test generation2|973|0更新时间：2025-07-16
- 摘要：Due to the parallelism and load balancing of parallel switches,the packets (or cells) within the same flow will be spread into several low speed switching fabrics for processing.When these packets are sent to the output,however,their sequence can not be guaranteed.For keeping packet order,this paper proposes a novel technique that includes the buffer structure of two stage Virtu al Input Queues (VIQ) and the scheduling algorithm named sequence keeping round robin (SKRR).The throughput and average delay performance of the technique are also analyzed.关键词：parallel switch;load balancing;delay;scheduling2|924|0更新时间：2025-07-16
- 摘要：A new label switching scheme based on regional code is proposed.The framework,operational principle and main characteristics of the system are described.The scheme divides the whole Internet into regions,and every region is assigned a unique fixed length regional code.The corresponding regional code label is inserted between data link frame header and IP packet header by accessing label switching when packet accesses label switching network.The core label switching identifies destination regional code of packet to follow the packet in label switching network only.It is showed by theoretical analysis and simulation that the network can greatly reduce the number of routing entries in routers,and largely lessen link bandwidth and processor overhead for maintaining these entries.The scheme can effectively overcome the Internet shortcoming of IPv4 address space exhausted,simplify the complexity of the implementation of the core switching,enhance the system throughput,and provide good QoS.关键词：label switching;routing lookup;regional code;aggregation gain2|1025|0更新时间：2025-07-16
- 摘要：Many new security problems will appear when the service capabilities are opened in NGN.The Parlay Framework,which is used to solve security issues when network capabilities are opened,is not able to handle all security problems appearing in the opening of service capabilities.Firstly,a number of security issues are discussed.Then a role model of the security service platform is provided which is used to solve these issues.At last,according to layered method,a concept model of the security service platform is put forward.Based on this model,it is quite easy and convenient to observe,analyze and study the security requirement,security services required and corresponding implementation mechanisms from different views.关键词：NGN;security service;opening service capability2|778|0更新时间：2025-07-16
- 摘要：We proposed a weighted max-min fair scheduling (WMFS) algorithm,that provides approximately normalized fair service guarantees and weighted max-min fair bandwidth allocation distribution among the contending flows,for input-queued crossbars.Furthermore,results from simulation show that the algorithm is able to achieve asymptotically 100% throughput and low cell latency under uniform traffic.关键词：quality of service;input queuing;weighted max-min fairness;normalized fair service2|1018|0更新时间：2025-07-16
- 摘要：The resource management policy of network nodes is the key element to influence the Quality of Service (QoS) of the future IP core transportation network.In this paper,aimed to distribute the data path resource,a hierarchical scheduling algorithm with hybrid algorithm structure and a buffer management mechanism with hierarchically dynamic threshold are proposed.The simulation results show that when the hierarchical resource management policy is adopted,the forwarding rate will approximate the theoretical value under the situation with non-uniform priorities distribution among output ports.关键词：core transportation network;scheduling algorithm;buffer management;QoS2|968|0更新时间：2025-07-16
- 摘要：A kind of tunable wavelength selective optical switch was proposed for the first time.It is based on Fabry-Perot cavity.The optical switch has two-input and two-output fiber ports.Each fiber carries N wavelengths,one or more of which can be selected.The maximum insertion loss is 3 dB and the tunable wavelength range is over 10 nanometers.The tuning mechanism is a sand-wiched multi-layered piezoelectric ceramic.The tunable span can reach 3.3 nm under 5 VDC voltages.The switching time is about 1 ms and the on/off ratio is over 30dB.The optical spectrum of the switch is also studied.At last,some applications of such optical switch are discussed.关键词：wavelength selective optical switch;Fabry-Perot cavity;piezoelectric effect;wavelength tuning;optical communication2|1445|0更新时间：2025-07-16
- 摘要：The large capacity ultra long haul(ULH) transmission is a very promising technology for future.This paper introduces the research and realization of 160×10Gb/s actual 3040km optical fiber transmission system without electronic regeneration in C+L Band.This system uses the channel interval 50GHz,line rate 10.7Gb/s,adopting CSRZ (Carrier-Suppressed Return Zero) as the line code and super FEC(Forward Error Correction),with OSNR(Optical Signal Niose Ratio) being larger than 15dB.Moreover,in the nationit first achieves successfully 10Gb/s signals in C+L band transmitted in an actual 3040km G.652 fiber line,and in the nationit first employs the C+L board band distributed Raman fiber amplifier on the ULH system,and the system runs error free for continuous 24 hours.These achieved practical significative experimental results offer the experimental foundations for studying the system perfor mances,parameters,characteristics and standards for ULH system applications.关键词：10Gb/s wavelength divided multiplexer system;ultra long haul (ULH);10Gb/s ultra long haul optical transmission;CSRZ(carrier-suppressed return zero);C+L band optical transmission;C+L board band Raman fiber amplifier2|1139|0更新时间：2025-07-16
- 摘要：The relation between channel spacing and effect of XPM and FWM in DWDM system was analyzed,and a new solution for simulation of high speed and long haul DWDM system was derived.In further numerical calculation,it was demonstrated that Q of center channel wasn't sensitive to increase of channel number when channel number is larger than 9 (in SMF) and 15 (in NZDSF) in DWDM system with 50GHz channel spacing.This result can be used in experimental design of DWDM system.关键词：XPM;FWM;DWDM2|1311|0更新时间：2025-07-16
- 摘要：Four kinds of routing and connection management schemes in hierarchical ASON are proposed in this paper.These schemes are Link State based Hierarchical Routing and Forward resource Reservation (LS HRFR),Link State based Source Routing and Forward resource Reservation (LS-SRFR),local information and Probing based Hierarchical Routing and Backward resource Res ervation (P-HRBR),local information and Probing based Source Routing and Backward resource Reservation (P-SRBR) respectively.The performances of these schemes in hierarchical networks are compared through discrete event simulation.The results indicate that,compared with link state based schemes,probing based schemes can improve the connection acceptance capacity of a network greatly in source routing scenarios while they hardly improve that capacity in hierarchical routing scenarios.关键词：automatelly switched optical network(ASON);routing;connection management;hierarchical routing;source routing2|946|0更新时间：2025-07-16
- 摘要：An experiment of two-stages four degrees high-order PMD compensation in 40Gb/s RZ optical communication system with a large PMD is achieved.The former stage adopts polarization controller and fixed time-delayed line of PMF.The second stage consists of a polarization rotator and a magneto optical crystal of tunable DGDs that are used to compensate remnant first-order PMD.The PMD monitoring technique is based on DOP as error signal.A novel practical adaptive optimization algorithm was introduced in dynamic adaptive PMD compensation.The experimental results show the improvement in PMD.With this compensator,a significant improvement of system performance can be achieved in the eye pattern of a received signal.Most first-order compensating ability of the compensator is 35 ps.Second order compensating ability of the compensator is 200ps2.The optimum compensating time is within several milliseconds.2|1015|0更新时间：2025-07-16
- 摘要：Ethernet-Passive Optical Network is playing a vital role in today's fibre to the home broadband access engineering.Delay compensation,Dynamic Bandwidth Allocation (DBA) and bridging are key technologies in EPON system design.To avoid several ONUs transmit collision and realize the ONU's plug and play function,absolute timestamp was used in the round trip delay compensation design,thus calculation of the round trip time (RTT) and ranging process can be easily done on timestamp bases.Also a native statistic algorithm based on each LLID,combining with its Service Level Agreement (SLA) and RTT value,was deployed in upstream DBA.It can bring low delay and high efficiency to bandwidth allocation.The proposed dynamic filtering database method was applied in EPON center system bridging,which achieved one OLT to many ONUs logic link MAC emulation,to comply with the traditional Ethernet LAN.These solutions have been tested strictly in WRI 863 R&D project and the results all accord with the anticipated analysis.The field experiment data given prove that the prototype system behaves very well when running triple play services.关键词：ethornet passive optical network (EPON);FTTH;DBA;absolute timestamp;dynamic filtering database;Logical link ID(LLID);SLA2|1301|0更新时间：2025-07-16
- 摘要：The restoration performance and reliability of connections depend on that of the signaling communications network (SCN) in the automatically switched optical network.This paper analyzes the performance,transmission delay and reliability of the SCN and gets some important factors which affect the performance and reliability of the routing and signaling.Then,a planning scheme for the performance of the SCN based restoration time of the connection and a planning scheme for the reliability of the SCN based on single link-fault no-failure restoration are addressed.The planning scheme for the performance enables estimation of the restoration time for connection.The planning scheme for the reliability solves the issue of no-failure restoration on single link-fault and improves the ef ficiency of the broadcasting of routing information.关键词：signaling communication networks(SCN);planning;performance;reliability;no-failure restoration2|829|0更新时间：2025-07-16
- 摘要：Compared to the Wavelength Routing (WR) and Optical Packet Switching (OPS) networks,Optical Burst Switching (OBS) is believed to be a more attractive technical solution for future Internet infrastructure.One of the issues of design of OBS switches is how to keep the implementation cost low while maintain high performance.A novel design of photonic switch for OBS net-works is proposed,which is called PM?1? P structure.The Internal Blocking can be effectively avoided in this structure,hence much higher throughput of data burst can be achieved.On the other hand,the proposed design uses less optical elements in terms of optical switching elements,multiplexers and couplers.It turns out to be a more cost-saving design than other photonic switches with similar throughput performance.Results of extensive simulations are presented,and the performance of proposed design is proved.关键词：photonic switch;internal blocking;fiber delay line;optical burst switching2|955|0更新时间：2025-07-16
- 摘要：The use of multi granularity OXC in DWDM network results in reduction of the number of ports both for the switches and for the optical multiplexers and de-multiplexers,which lead to cost saving.However,it introduces more difficulties for the routing and wavelength assignment problem.In this paper,a new model,called Multi-Dimension Graph,is proposed to provide an exact description of the states of multi granularity WDM network.The algorithm based on the MDS-G can solve routing and wavelength assignment subproblems in multi-granularity networks simultaneously.The simulation results prove that the algorithm based on the MDS-G performs better than existing algorithms that deal with routing and wavelength assignment separately.关键词：optical networks;multi-granularity optical(MG-OXC);RWA;MDS-G2|848|0更新时间：2025-07-16
- 摘要：By analysis of optical internet architecture,a new hybrid model architecture for network is presented.Its characteristic is that a signal transformation mechanism is used in optical node,and the node functions for overlay and peer model are provided.The internetworking from a core optical network to different model networks are realized,and the valid supervision for management plane to control plane is taken.Simulation results indicate the technology is effective.关键词：optical internet;architecture;signal transform;hybrid model2|841|0更新时间：2025-07-16
- 摘要：We report a heterogeneous ASON test-bed composed of two different types of OXC.A connection control interface in each node hides the architecture difference for control plane.A unified control plane as well as a friendly network manager runs in the heterogeneous domain to demonstrate establishment,release and recovery of virtual wavelength paths.关键词：automatically switched optical networks(ASON);control plane;heterogeneous network;virtual wavelength path;mesh topology2|932|0更新时间：2025-07-16
- 摘要：A generalized multi-carrier (GMC) wireless transmission scheme is presented in multi-input and multi-output (MIMO) channel environments for beyond 3G mobile communications.Several key techniques including the design and implementation of the GMC synthesis/analysis system,adaptive double-cyclic timeslot structure,pilot design and channel estimation,and iterative detection/decoding are briefly discussed.Link-level simulation results in Rayleigh fading MIMO channels are provided.关键词：multi-carrier transmission;multi-input and multi-output (MIMO);filter bank;channel estimation;detection/decoding2|1407|0更新时间：2025-07-16
- 摘要：This paper proposes a new method of pilot arrangement for channel estimation in Single-Carrier modulation with Frequency Domain Equalization (SC-FDE) systems,and analyzes its performance.The new method,which is based on Hadamard transform and interleaver,can eliminate cross interference between pilot and data part in severe multipath environment,and can achieve accurate channel parameters easily.Theoretical analyses and simulation results show that this scheme with low overhead and low implementation complexity has good performance in channel estimation,and it is suitable for mobile transmission with high spectrum efficiency even in time-varying multipath channel.关键词：channel estimation;pilot;single-carrier modulation;frequency domain equalization2|1677|0更新时间：2025-07-16
- 摘要：Recently,a new generation mobile communication system,which is named B3G (Beyond 3G) or 4G,has been put into the schedule and become one of the hotspots of international research.On the other hand,Multi-In-Multi-Out (MIMO) system is a very promising frame for B3G,not only for its high potential of increasing frequency efficiency,improving communication quality and possessing flexibility structure,but also for its capability of providing plenty of room for all kinds of new technologies.Based on this frame,a novel network constructing policy-Group Cell and its special handover method-Group Handover are put forward to combat the frequent handover problem in smaller cells.In this paper,the basic idea of the two concepts is explained in detail,and problems together with research directions in this area are investigated.关键词：beyond 3G;multi-input multi-output (MIMO);cellular;handover;group cell;group handover2|1957|0更新时间：2025-07-16
- 摘要：Transmission Optimization for Multiple Input Multiple Output (MIMO) Multi access channel with delay limited constraints is analyzed.Applying standard optimization method,the transmission strategies and optimal power allocation schemes are proposed for users.To reduce the complexity of the optimal solution,the analysis is considered in two stages.The first stage gives the distributed optimal pre-codeword ensembles for users using successive decoding and interference avoidance methods.The second stage allocates power for users in the equivalent single-user channel using the water filling method.The best possible ordering of users for successive decoding is also involved.We propose a suboptimal power control strategy based on individual SINR constraints as a substitute for the optimal one when employing the MMSE receiver with successive interference cancellation.Numerical results show that the optimum transmission strategy and the suboptimal one combined with power allocation have the similar performance and both are capable of improving the system capacity and performance.关键词：multiple-input multiple-output;multi-access channel;delay-limited capacity;power allocation;interference avoidance2|892|0更新时间：2025-07-16
- 摘要：Providing seamless mobility support is one of the most challenging problems towards the system integration of fourth generation (4G) all-IP wireless networks.Mobility management protocols can be operated in different layer (such as link layer,network layer,transport layer and application layer).Each of them comes with its own advantages and disadvantages according to the characteristics of its layer of operation.Architecturally,the network layer is the "right layer",but the protocol stack needs to be modified.Because of the transparency to the lower layer characteristics,application-layer mobility management protocol seems a good choice,but it introduces larger latency.Therefore,a real open,accommodative but still efficient mobility management solution is called for by the next-generation wireless system.关键词：mobility management;network layer;application layer;all-IP network2|1246|0更新时间：2025-07-16
- 摘要：In dense multipath channels,rapid acquisition of Ultra Wideband (UWB) signals is a crucial problem due to very high pulse rate and extremely low per-path energy.This paper presents a two-stage acquisition scheme to improve acquisition performance in the Impulse Radio UWB systems.Specifically,two kinds of sub-optimal maximum-likehood criteria are proposed for a coarse search.Then,a maximum/threshold-crossing criterion is employed for a fine estimation within the obtained limited region.The probability of acquisition is redefined from the view of energy capture that may guarantee expected system performance after acquisition.The impact of captured energy on system performance,as well as,the selection of criterion parameters are evaluated and analyzed in terms of simulation.关键词：ultra wideband;multipath;acquisition2|1112|0更新时间：2025-07-16
- 摘要：Referring to the geometrically based single bounce (GBSB) model,a new geo-propagation model is proposed to predict the delay spread as well as the direction-of-arrival of multipath components in channels for high altitude platform station (HAPS) communications.Furthermore,an approach to calculate the probability of existence of single bounce paths caused by building blockages is given.By using the model,numerical simulation gives the power delay profile and the joint time-angle spread of the HAPS channels.关键词：blockage;multipath channel;geometrical model;HAPS2|1303|0更新时间：2025-07-16
- 摘要：The impact of timing error on the receiver's BER performance of TDD phase pre-equalized OFDM systems is investigated.The analytic BPSK BER expressions of ideally and nonideally pre-equalized OFDM systems in multi-path Rayleigh fading environments are obtained.The corresponding simulations verify the analytic expressions.Compared with the theoretical system performance bound of Rayleigh fading,the performances of ideal and nonideal pre-equalization entail loss of 1dB and 3dB respectively,when the normalized timing error is 1/8.When it is 1/4,both of the two systems' performances degrade severely.At the same time,the gap between them diminishes.In that case,timing error becomes dominant among those elements which would affect systems performance.关键词：orthogonal frequency division multiplexing(OFDM);pre-equalization;timing error;channel estimation2|1007|0更新时间：2025-07-16
- 摘要：The article provides an overview of Smart Antenna technology in wireless LAN systems.Since Smart Antenna technology has powerful spatial processing ability,it is regarded as a promising solution to enhancing the data rates and capacity of wireless LAN systems.This article discusses the switched beam based,the adaptive array based and Multiple-Input-Multiple-Output based wireless LAN systems and their relevant key technologies.A set of small size,practical switched beam antenna system,well suited for IEEE 802.11b Standard,is designed and tested.The antenna system has 9dB gain and can be applied to the wireless Access Point.Based on the testing results,an improved scheme is also proposed,with all the beams cophasal excited.关键词：wireless LANs;smart antenna system;switched-beam;adaptive array;multiple input multiple-outputq3|1908|0更新时间：2025-07-16
- 摘要：Wireless LANs have achieved a tremendous amount of growth in recent years.The IEEE has standardized the 802.11 protocol for Wireless LAN.The performance of the Medium Access Control has been examined over the past years and several models had been provided.In this paper,a simple but accurate analytical model is presented to compute the saturation throughput and access delay of 802.11 DCF.Compared with other models,this model is able to predict the behaviors of 802.11 more simply and accurately.关键词：wireless LAN;saturation throughput;access delay2|1124|0更新时间：2025-07-16
- 摘要：IP based mobility management scheme makes mobile host roaming in heterogeneous network without changing its IP address.How to select the best candidate network and when to make handoff have a strong effect on performance of mobility management.This paper proposed a location information based handoff decision algorithm.MH can select right candidate access router and make handoff in best occasion.Theoretical analysis and simulation show that number of handoff and packet loss rate can be decreased.关键词：MH;AR;LBHD2|1072|0更新时间：2025-07-16
- 摘要：An ultra-wideband orthogonal frequency division multiplexing system (UWB-OFDM) may be an ideal transmission/access solution for short-range,high data rate,wireless networks.As the occupied bandwidth increases,however,its implementation becomes more and more difficult.To solve this problem,we investigate a few of typical implementation structures,frequency-domain direct spreading (FDDS),multi-branch diversity (MBD),multi-branch frequency-domain equalization (MBFDE),double-layer multi-carrier frequency division multiplexing (DLMC-FDM),double-layer multi-carrier frequency diversity (DLMC-FD),double-layer multi-carrier frequency-hopping (DLMC-FH),and their combinations,for UWB-OFDM systems.The analysis focuses on the characteristics of each structure and the relationship between any two structures.The findings try to provide a theoretical foundation for the design of UWB-OFDM systems.关键词：ultra-wideband;orthogonal frequency division multiplexing (OFDM);frequency diversity;implementation structure;parallel processing2|866|0更新时间：2025-07-16
- 摘要：KTRA (Kernel Tree Routing Algorithm) is a new self-organization algorithm for mobile Ad Hoc networks.It recon structs the net as a logical tree topology,thus the nodes need only to maintain a part of routing information for networking and routing,and the update requirement is restricted in the area of branch.KTRA has low delay as the preactive tech and high flexibility as the reactive tech.The idea and technology of KTRA and the results of the KTRA applied to an experimental Ad Hoc network are described.关键词：AdHoc network;mobile;tree topology;routing algorithm;KTRA(kernel tree routing algorithm)2|974|0更新时间：2025-07-16
- 摘要：Software component library is the most effective way to manage the software component.With the development of the distributed component,the component library manages not only the traditional off-line components,but also on-line components.In addition to this,the component library must support QoS (Quality of Service) of component.In order to tackle the problem,first a component quality model,the ways of quality attributes measurement and corresponding specification are introduced in this paper.Then a method to support the QoS of component based on the model and specification mentioned above are put forward.At last,the implementation of the method in Jade Bird component library management system (JBCLMS) is described.关键词：quality of service(QoS);component library;subjective feedback;objective feedback2|863|0更新时间：2025-07-16
- 摘要：This paper proposes a new pervasive computing paradigm:transparence computing.The hardware environment of this paradigm still consists of clients and servers.However,the clients should be computing devices designed with the transparence computing paradigm.These devices can be desktop or mobile one,such as PDA or mobile phone.The server of this paradigm is a machine with a hard disk,including a general PC.In transparence computing paradigm,no OS,middleware and any application program are installed in the clients,they are loaded from the server through network dynamically when users want to run them in a client.Users can choose any OS and application programs running on it,which has been installed in the server and can be run by the clients.Transparence computing paradigm can improve the security of the information systems,reduce the complexity of the managements,improve the sharing of software and reduce the costs of hardware and software of information systems greatly.This paper introduces the concept and architecture of the transparence computing paradigm.Moreover,we also give an application example of this paradigm.This example is Manageable Multimedia Network Computer (MMNC),which has been developed and commercialized.MMNC system can show the transparence computing is feasible and effective.关键词：transparence computing;computer network;client/server2|3066|0更新时间：2025-07-16
- 摘要：IEEE nomenclature and criterion of software engineering defines that Metric is the quantificational measurement of a system,component,or a degree with any specifically attribute.In order to assist such quantificational measurement,a Java oriented measuring tool was designed.Firstly a series of definition of algorithms of measurement for Java was given.Then the paper discussed how to implement these algorithms by a layered architecture.The measurement tool designed by this way was extensible.It can help to improve the quality of programs.关键词：object-oriented metric;arithmetic of measurement;design of Java measurement tool2|1365|0更新时间：2025-07-16
- 摘要：J2EE specifications haven 't yet definitely defined any common service which provides load balance.To meliorate the scalability of network software,however,supporting load balance at middleware level has become an important issue which should be focused on by all J2EE application server providers.In this paper,we first analyze load-balance related technologies currently used on J2EE platforms.After that,we present a flexible and customizable load balancing framework which supports several load balancing strategies and describe the implementing details of the framework on a J2EE application server PKUAS.关键词：load balance;middleware;J2EE(Java 2 platform, enterprise edition);EJB(enterprise Java beans)3|860|0更新时间：2025-07-16
- 摘要：Workflow technology has been a research hotspot of computer application domain.WfMC has brought out a reference model of workflow management system,which includes process definition tools,workflow engine,invoked APIs,client application and process monitoring tools.Based on JadeBird workflow process meta-model,this thesis discussed the design of the process monitoring tools.关键词：workflow;workflow management system;process monitoring2|1076|0更新时间：2025-07-16
- 摘要：Advanced Audio Coding (AAC) is the standard audio coding specification of MPEG-4.As description of AAC audio coding,the high frequency part of audio is always omitted,and only the low frequency part of audio will be coded to enhance the audio compression efficiency.The high frequency reconstruction technology plays an important role in the AAC decoder design to improve the output audio quality.This paper discusses the basic principles of high frequency reconstruction based on spectral bandwidth replication (SBR) technology.The implementation of an AAC decoder with SBR is presented in this paper.Some evaluation results of the implementation show its efficiency of audio decoding.关键词：high frequency reconstruction;advanced audio coding (AAC);spectral bandwidth replication(SBR);aacPlus2|1357|0更新时间：2025-07-16
- 摘要：Face hallucination is to synthesize a high-resolution facial image from a low-resolution input.A novel two-step approach to hallucinating faces based on the MAP criterion is presented in this paper.First,a linear relationship between high-resolution and low-resolution facial images is established by applying PCA on both of them,and the global image,which is similar to the original high-resolution image,is reconstructed based on the MAP criterion.Second,a linear model between the residual image (the difference between the original image and the global image) and the low-resolution residual image (the difference between the low-resolution input and the manually down-sampled global image) is built,and,following a MRF prior,the optimal residual image is estimated based on the MAP criterion again.Experiments demonstrate that our approach can be applied to yield 4-8 fold super-resolution with high-quality hallucinated results.关键词：face hallucination;resolution enhancement;MAP criterion2|881|0更新时间：2025-07-16
- 摘要：With the direction of the theory of Bionic Pattern Recognition,this paper puts toward an extended nearest Neighbor method.It makes use of the continuity rule between the samples which belong to the same pattern to increase the number of samples.We cover the possible samples by means of the combination of the hyperspheres.This method is proved effective by simulation result of the face recognition experiment.关键词：bionic pattern recognition;nearest neighbor method;face recognitionq2|1202|0更新时间：2025-07-16
- 摘要：Grid portal gives a center access point to access Grid applications and resources.Currently the existing Grid portals are mainly designed for computational Grid which puts focus on how to view files,submit and monitor jobs that alleviate the complex ity of using the Grid application,while the information Grid portal puts focus on how to provide various services in Grid environment to the public rather than scientists.In Information Grid portal the portal information service,workflow service and transaction service are very important to achieve the goal of building a web interface for citizens to seamlessly and transparently use the services located in Information Grid environment.This paper reports the current research and implementation in Information Grid portal based on ShanghaiGrid.2|736|0更新时间：2025-07-16
- 摘要：During the process of component reusing,users often have no all-around understanding of the component description mechanism.So it’s difficult for users to propose exact retrieval requirements,which leads to lower precision.We refer to association mining theory in data mining field,and present a self-adaptive component retrieval model with user-feedback and the association mining-based self-adaptive learning algorithm.It can obtain the internal relationships between users’ explicit retrieval conditions and their implicit requirements through mining in the retrieval history,thus making the retrieval conditions more complete and precise,which increase the precision of component retrieval.The experimental results show that this solution is feasible and effective.关键词：component repository;component retrieval;faceted description;association mining;self-adaptive2|970|0更新时间：2025-07-16
- 摘要：Reflective middleware opens up the implementation details of middleware platform and applications at runtime to improve the adaptability of traditional middleware.However,such openness brings new threats to security of middleware platform and applications.This paper studies how to protect a reflective J2EE application server with a set of access control mechanisms.At first,a computation model of reflective middleware is built up and illustrates that the access control of reflective middleware is far more com plex and difficult to implement than that of traditional middleware.With the model,all potential access control points are identified while only some of the points require access control mechanisms.It reveals that the complexity and cost of the access control framework are mainly related to the concrete implementation of reflective mechanisms.At last,the framework is implemented mainly by reusing the access control mechanisms existing in traditional middleware and the performance is evaluated.2|868|0更新时间：2025-07-16
- 摘要：Meta models and meta-modeling are becoming popular as one of techniques in the main steam of software develop ment,resulting from the fact that general modeling languages such as UML become ubiquitous.Firstly,this paper analyzes the features of meta model architecture and corresponding requirements,including especially meta model assessment,of managing meta information.Taking OMG's four level meta model architecture as an example,UML meta model,as the core part of the architecture,is the focus of debating among researchers and practitioners.The situation proves the necessity of UML meta models measurement.The hall marks in terms of meta and OO metrics provide the feasibility of the evaluation.Secondly,a quantitative method,measuring the stability from the internal perspective and design quality from external perspective,is applied to assess 5 UML meta models.The results of the assessment are then analyzed in comparison with related subjective comments on UML evolution.The promising application of the method is presented as a conclusion.关键词：meta model;measurability;metrics;unified modeling language(UML)6|1506|0更新时间：2025-07-16
- 摘要：Coalition Formation is a key topic in Mult-iAgent System.The current strategies don't embody the difference of Agents.contribution to coalition for allocating utility averagely,so they cannot guarantee the coalition stability.This paper presents a novel behavior strategy for coalition formation.It remains the principle of non-reducing utility allocation,and improves the justice of allocation for accrued utility.In task oriented domains this strategies can achieve a global optimal solution,which is stable,speedy and distributed.关键词：multi-agent system;coalition;behavior strategy;auction2|955|0更新时间：2025-07-16
- 摘要：How to universally measure the quality of fused image is one of the most important problems in image fusion.This paper analyses the measures of fused image quality in existence,then presents a new evaluation of fused image,which combines objective and subjective factors.In addition,it considers the characteristics of human visual system without reference image and can be used to choose the best algorithm in image fusion applications.The experiments of different kinds of images and image fusion algorithms demonstrate that it is a practical,effective,and universal measure of quality of fused image.关键词：image fusion;quality measure for image;human visual system2|4103|0更新时间：2025-07-16
- 摘要：A selective testing method for reactive systems is presented.UML Statecharts is employed to model the system under test (SUT) and temporal logic is used to specify the functional property.Then targeted test sequences are derived from the model according to the given property.This method has been implemented in a property-oriented testing tool.Experimental results show that testing efforts can be focused on behaviors of interest of the SUT.With the appropriate extensions,this method can also be applied to real time systems.关键词：software testing;reactive system;unified modeling language(UML) statecharts;temporal logic2|770|0更新时间：2025-07-16
- 摘要：How to realize software coordination in the Internet environment becomes a hotspot nowadays.Traditional Single-pattern coordination model can not adapt to the Internet environment.Multi-pattern coordination model will help a lot.This article proposes a space-based coordination architecture,in which space is a shared data store.This kind of architecture has outstanding flexibility and adaptability,which gives a good supporting to Multi-pattern coordination.关键词：coordination;space;tuple;match4|904|0更新时间：2025-07-16
- 摘要：Software testing is an important method of assuring quality and enhancing reliability and path coverage is an essential criterion for testing adequacy.Since the rigid path cover testing is infeasible,we select and test some key paths,which outweigh others on affecting the overall quality of the system,to enhance test efficiency and profit.A general statistics-based automated tool aiming at object-oriented software systems was proposed.By static analysis and interpolation on code,this tool offers a diagnosis of statistical data derived from continual executions,which are driven by random test cases,for information of selecting key paths in correctness testing and reliability testing.Primary idea,corresponding algorithms of this tool,and some problems in implementation are exposed.关键词：path-oriented;object-oriented testing;interpolation;Statistics4|1080|0更新时间：2025-07-16
- 摘要：Based on distributed artificial intelligence,the paper put forward MAS based distributed intelligent malfunction diagnosis method and process,and discussed pattern-clustering based malfunction solution-finding mechanism and the identification and decomposing of a diagnosis task.It also studied the restriction and relationship of multi-agent in the macroscopic sense,and designed the expression mechanism for applied agent's work status.Else it ascertained the influence and the communication and the interaction among applied agents,and constructed a multi-agent fuzzy related model.The last aspect is that the paper presented an integrated descriptive structure of local diagnosis decision and global diagnosis decision,and established a distributed agent diagnosis system structure and its prototype model system too.Diagnosis system can be divided into applied agent and service agent,using distributed communication mechanism to realize intercommunication of information,realize distributed system s information exchange and diagnosis,and enhance system's efficiency,security and error standing for problem-dealing.When the model was applied in the power enterprise's security monitor system the result was similar to expert system,and the model overcame many deficiencies of previous monitor diagnosis system,enhanced the efficiency of the enterprise security running.关键词：intelligence malfunction diagnosis;multi agent system (MAS);task decompose;cooperation control5|1137|0更新时间：2025-07-16
- 摘要：Preservation of consistency is the ultimate criterion of component evolution.With component interaction processes and inspired by typing system and process construction methods of Pi-calculus,component interaction typing system and interaction-based component model are proposed.To ensure correct interaction behaviors of component ports and channels,service port type and channel type are introduced.At the same time,consistent component system is defined based on the notion of well-typedness in Pi-calculus.Then,based on the peculiarity of component evolution,static and dynamic evolution rules are proposed.At last,method for recovering from inconsistent state is introduced.关键词：component system maintenance;component interaction;component evolution;Pi-calculus2|1056|0更新时间：2025-07-16
- 摘要：With the development of distributed component technology,people set more and more focus on the diagnosis problem in such systems.Whereas,the current research on the diagnosis problem about distributed component systems often omits an important factor the system semantics.The system semantics are composed of the structure and behavior information under the normal and abnormal conditions.The paperproposes a novel ideal of diagnosis,which is a semantic centric method.After introducing principle of model based diagnosis,the paper puts forward a novel model compiling approach by providing the time series information in the Horn clauses,which can express complicated temporal semantics and compute the minimal diagnosis by the theorem provers of first order logic.Further more,the paper sets forth the model compiling method by a philosopher dinner problem.In the end,the diagnosis subsystem implemented in StarCCM is introduced,which consists of the diagnosis engines,diagnosis agents and diagnosis callback interfaces.The novel diagnosis model compiling approach is proved to be applied in the distributed component system effectively.关键词：fault diagnosis;model;semantic;time series;distributed components;common object request broker architecture (CORBA)2|929|0更新时间：2025-07-16
- 摘要：It may be desirable to manage non-canonical software requirements to facilitate requirements development and improve the quality of requirements specifications during the requirements stage.To address this,the framework for managing frequent non-canonical requirements is provided.The technique for reasoning about requirements in the presence of inconsistency plays an important role in the framework.Moreover,it could be used to manage other non-canonical requirements associated with inconsistency,including vague requirements or redundant requirements.关键词：requirements engineering;non-canonical software requirements;inconsistency3|1095|0更新时间：2025-07-16
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