P2P系统中降低错误相关性的方法

目前许多P2P网络存储系统都采用了m／n容错机制来提高系统的可用性和可靠性,但是在实际应用中,服务器之间发生相关错误会导致这种容错机制具有低容错率．针对这种问题,描述了一种在P2P系统中寻找低错误相关的服务器节点集合的方法,m／n容错机制可以通过使用此集合中的服务器节点来提高其容错率,从而使得系统具有高可用性和可靠性,并对此方法进行了实验分析,验证了方法实用有效．     

Test Time Minimization for Hybrid BIST of Core-Based Systems

This paper presents a solution to the test time minimization problem for core-based systems. We assume a hybrid BIST approach, where a test set is assembled, for each core, from pseudorandom test patterns that are generated online, and deterministic test patterns that are generated off-line and stored in the system. In this paper we propose an iterative algorithm to find the optimal combination of pseudorandom and deterministic test sets of the whole system, consisting of multiple cores, under given memory constraints, so that the total test time is minimized. Our approach employs a fast estimation methodology in order to avoid exhaustive search and to speed-up the calculation process. Experimental results have shown the efficiency of the algorithm to find near optimal solutions.     

远距离射频识别系统及其应用简论

RFID(Radio Frequency Identification)采用无线射频实现可移动存储设备与计算机或PLC之间的数据交换。一个典型的RFID系统包括载码体(即数据存储器),与载码体通讯的天线,以及处理天线与PC(或PLC)之间通信的控制器(天线与控制器一体时,我们称之为只读器或读写器)。射频识别技术被广泛应用于工业自动化、商业自动化、交通运输控制管理、防伪等众多领域,甚至军事用途。     

WCDMA中RF优化及路测数据分析方法

WCDMA网络是目前在用的主流网络,WCDMA的网络优化对用户和运营商有重要作用。RF优化是WCDMA网络优化的主要部分之一。RF优化主要结合路测数据进行。因此,本文通过对RF优化流程及路测数据分析方法的分析,提出路测的主要的KPI指标,并对弱覆盖、导频污染、邻区漏配和切换问题等常见的网络优化问题进行分析。     

WCDMA中RF优化及路测数据分析方法

WCDMA网络是目前在用的主流网络,WCDMA的网络优化对用户和运营商有重要作用。RF优化是WCDMA网络优化的主要部分之一。RF优化主要结合路测数据进行。因此,本文通过对RF优化流程及路测数据分析方法的分析,提出路测的主要的KPI指标,并对弱覆盖、导频污染、邻区漏配和切换问题等常见的网络优化问题进行分析。     

小波变换在单片机信号去噪中的应用

在单片机系统工作环境中存在着各种噪声干扰,尽管已采取了一些抗干扰措施,但不可避免会有噪声进入系统。该文根据单片机系统中的信号特点,基于小波变换自动变焦功能,提出用小波变换对含噪信号进行去噪。基于小波变换的去噪是在对含噪信号进行分解的过程中,通过门限方法抽取有用信号的小波系数,然后重建而得以实现。仿真结果表明了在单片机控制系统中利用小波变换进行信号去噪的可行性和有效性。     

Logical Time in Distributed Software Systems

This paper presents a survey of implementation of logical time in asynchronous distributed systems. We provide an argument that justifies the use of logical time as a mechanism for detecting causal relationships between events. Further, we formally introduce the notion of a logical time system (a logical clock) and proceed to discuss the properties of the scalar, vector, and matrix clocks. Finally, we consider the modifications of the vector clock that reduce the average communication overhead while retaining the property of isomorphism.     

Decreasing Computational Time of Urban Cellular Automata Through Model Portability

This paper investigates how portability of a model between different computer operating systems can lead to increased efficiency in code execution. The portability problem is not a trivial one, as many geographic models are designed to be run inside a set environment (Unix, Solaris, Linux, and Windows), and are further limited by hardware constraints. The SLEUTH urban growth model [K.C Clarke, S. Hoppen, and L. Gaydos. “A self-modifying cellular automaton model of historical urbanization in the San Francisco Bay area”, Environment and Planning B, 24:247–261, 1997.] was implemented under three different operating systems (Solaris, Linux, and Windows). Results suggest that the model's performance is optimized by porting it from its original environment (Unix/Solaris) to Linux or Windows where faster processors are available. While the results show optimization of model performance, there are some suggestions of computational bottlenecks that may eventually limit the increased performance of the model. Regardless, the research demonstrates that the portability of a model can lead to not only to a decrease in computation time, but may increase the viability in practical applications and attract a wider user base.     

Empirical Test Observations in Client-Server Systems

Formal statistical analysis of defect databases for two commercial client-server products for disparate applications - C-language parsing and geophysical modeling - tests the hypothesis that defects in the graphical client mask more important underlying defects in the computational server. It also quantifies the benefit of continued testing after delivery in terms of reduced software defect densities apparent to end users.     

工作流系统中的时间管理

介绍了工作流系统中时间管理的范畴。从工作流系统中时间约束的建模、时间约束的执行和运行后的数据分析三个方面全面概述时间管理的研究内容,为在实践中构建具有时间约束的工作流系统奠定了理论基础。     

基于LUA脚本的无线模块自动化测试

分析传统无线模块测试方法的制约性,设计和构建了基于LUA脚本的无线模块自动化测试平台,并且能够有效地加快无线模块测试进度,提高测试脚本的可复用性。该平台通过对被测对象的研究,对测试方法、系统架构、系统软硬件通用性的分析,并引入了基于LUA测试脚本的程序开发环境,实现了无线模块的自动化测试。通过不同的测试用例结果分析表明：该测试方法相对于传统无线模块测试方法缩短了测试周期,降低了开发成本,减少测试开销,运行稳定可靠,达到预期的目的。     

基于ATEasy的通用射频测试系统研究与实现

针对引进现代电子装备及系统中射频模块故障频发的问题,为实现对引进电子装备及系统射频模块的自动测试及故障诊断,达到降低外送维修成本、缩短维修周期、提高维修效率等目的,研制通用射频测试系统;通用射频测试系统硬件基于GPIB及VXI总线技术集成精密测试仪器仪表实现,利用VXI矩阵开关构建模块串并回路,设计系统通用接口适配器,提出自动测试射频模块工作电流及电压的电路设计;软件架构及测试程序采用美国GEOTest公司的ATEasy8.0;目前基于ATEasy集成开发环境开发射频模块测试程序,已实现20余种射频模块的自动测试及故障诊断;经验证,测试结果有效;该系统为引进现代电子装备及系统射频模块的测试开辟新的途径,提供新的支持.     

通用射频参数测试系统软件架构设计

针对射频参数测试系统的设计复杂性和可扩展性需求,提出一种新的测试系统软件架构;通过将测试过程中抽象为测试框架和测试方法集,实现了通用的射频参数测试系统软件架构;测试框架包含测试资源管理、测试流程调度、数据管理以及图形用户界面等复杂的软件组件,但没有任何具体测试操作实现;测试方法是执行具体参数测试的组件,通过抽象测试方法接口访问测试系统资源;由于测试方法组件的开发难度很低,便于快速扩展应用,此软件架构已应用于多套实用射频参数测试系统。     

大时滞系统时间协调参数调整控制策略

针对大时滞系统难以实现闭环稳定控制的问题,引入脉冲响应等效系统的概念,提出时间协调参数修改控制算法.该算法由两部分组成.一是通过时间协调原则修改控制器的输出;二是利用脉冲响应等效系统来修改控制器的参数,使脉冲响应等效系统和大时滞系统匹配,跟踪被控制对象参数变化产生自适应性,保证控制系统精度和稳定性.并用于氧化铝生产过程碳酸化分解工序,将原来手动操作开环控制改为闭环控制,提高了分解率和产品的合格率.该控制算法是递推算法,计算量小,便于在线实现.     

基于Web的自适应考试系统

本文介绍了计算机化自适应考试（Ｃｏｍ ｐｕｔｅｒｉｚｅＡｄａｐｔｉｖｅ Ｔｅｓｔ）的基本理论和过程。并提出了一个基于Ｗｅｂ自适应考试系统的框架。     

Integration and Test Sequencing for Complex Systems

The integration and test phase of complex manufacturing machines, like an ASML lithographic manufacturing system, is expensive and time consuming. The tests that can be performed at a certain point in time during the integration phase depend on the modules that are integrated and, therefore, on the preceding integration sequence. In this paper, we introduce a mathematical model to describe an overall integration and test sequencing problem, and we propose an algorithm to solve this problem. The method is a combination of integration sequencing and test sequencing. Furthermore, we introduce several strategies that determine when test phases should start. With a case study within the development of a software release that is used to control an ASML lithographic machine, we show that the described method and strategies can be used to solve real-life problems.      

An ILC-Based Adaptive Control for General Stochastic Systems With Strictly Decreasing Entropy

In this paper, a new method for adaptive control of general nonlinear and non-Gaussian unknown stochastic systems has been proposed. The method applies the minimum entropy control scheme to decrease the closed-loop randomness of the output under an iterative learning control (ILC) basis. Both modeling and control of the plant are performed using dynamic neural networks. For this purpose, the whole control horizon is divided into a certain number of time domain subintervals called batches and a pseudo-D-type ILC law is employed to train the plant model and controller parameters so that the entropy of the closed-loop tracking error is made to decrease batch by batch. The method has the advantage of decreasing the output uncertainty versus the advances of batches along the time horizon. The analysis on the proposed ILC convergence is made and a set of demonstrable experiment results is also provided to show the effectiveness of the obtained control algorithm, where encouraging results have been obtained.