Self-assessment in a feasible, adaptive web-based testing system

Adaptive testing systems generate tests for assessment that are tailored to each student. In these tests, students are assessed through a process that uses Item Response Theory (IRT), a well-founded psychometric theory. This theory is responsible for estimating student knowledge, determining the next question that must be posed at each moment, and deciding test finalization. System of Intelligent Evaluation Using Tests for Teleeducation (SIETTE) is a Web-based environment for generating and constructing adaptive tests. In SIETTE, teachers can create tests for self-assessment. In this kind of test, questions are posed one by one, and the correction of each question is shown immediately after the student's answer. Along with this correction, and in terms of the student's answer, feedback is provided. Feedback consists of pieces of knowledge that help students detect misconceptions or reinforce concepts correctly learned. Furthermore, hints can be included when questions are posed to supply students with some kind of help or explanation about the stem. As a result, this kind of test can be used not just for assessment, but also for instructional purposes. The first goal of this paper is to show how SIETTE can be used for instructional purposes, by combining adaptive student self-assessment test questions with feedback and hints. This paper also shows that the Web is a feasible platform for the generation of adaptive tests, supporting the use of SIETTE for this purpose.     

计算机检修管理系统中Gateway的设计与性能测试

针对电厂状态检修的实际需求,采用国产的三维力控软件平台与PI数据库和Oracle数据库相结合,完成了石嘴山电厂状态检修系统计算机检修管理系统(CMMS)的详细设计。其中,状态检修系统需要的绝大部分实时数据都取自厂级监控信息系统(SIS)的PI实时数据库,因此,PI数据库和力控实时数据库之间的接口Gateway的性能将直接决定整个状态检修系统的性能。采用VC/C 、PI数据库的API和力控平台的ActiveX控件,开发了PI和力控系统间的Gateway,并对Gateway的结构进行了优化。通过对软件平台中Gateway的极限测试表明,该软件平台能满足状态检修系统性能指标的要求。     

嵌入式软件测试系统的设计与实现

随着嵌入式技术的发展,如何对它进行快速有效的测试已经成为现在的一大热点.本文提出了一种通用的嵌入式软件测试系统的基本框架图,该测试系统分为五个功能模块: 功能测试模块,代码性能测试模块,数据分析和文档报告模块和通信接口转换模块.并且使用程序插桩的方法,设计并实现了基于汇编的嵌入式自动测试系统.有效的解决了传统手工测试程序带来的一些问题,满足了国内用户对嵌入式汇编进行测试的需求.     

A computerized technique for reliability evaluation in power system transmission planning

The paper discusses two computer programs to calculate the composite system reliability indices, the loss of load probability and the expected demand not served, for use in long-range power system transmission expansion planning. The programs are based on the maximum-flow-minimum-cut technique and a decomposition principle which transforms the network capacity state space into nonoverlapping subsets to calculate the reliability indices.A modified version is also discussed in which the respective individual load reliability indices at each bus are determined.The programs have been applied to different test systems and typical results are presented in the paper.     

Design and implementation of an adaptive Kalman filtering for the launcher of multiple launch rocket system

Practical application for performing an adaptive Kalman filtering with a digital signal processor is studied. A multiple launch rocket system (MLRS) is considered, and an adaptive Kalman filtering is designed for the state estimation of the launcher by using the measured outputs from a fiber optical gyro mounted on the MLRS. The proposed algorithm remains convergent in the presence of noise covariance errors. The performance of the proposed method is demonstrated by simulations and compared with other types of Kalman filtering algorithms. Eventually, an experiment is implemented for the state estimation of the launcher of MLRS using the TMS320F2812 digital signal processor.     

OFDM系统中自适应调制结构设计与性能分析

自适应调制技术作为一种有效提高宽带无线通信系统性能的方法,得到了人们的广泛关注。对OFDM自适应调制技术进行了研究和分析,设计了基于子载波的OFDM自适应调制结构,并对该结构的性能进行了仿真分析。仿真结果表明:自适应调制技术能根据信道情况自适应改变系统子载波的调制方式,能有效地提高系统数据传输效率,改善系统的性能。     

Development and field testing of an adaptive flicker controller for15-kV systems

An adaptive flicker controller (AFC) device is developed and field tested. The AFC control strategy is described for systems with large and rapidly varying loads connected to a weak feeder. The control algorithm does not require knowledge of system parameters such as line impedance. The algorithm is fast and adaptive to system variations. The AFC is tested in a utility distribution system having a severe voltage flickering problem. The hardware and software required to implement the AFC is discussed. The results of a field test are presented and analyzed     

Coupling an adaptive protection system with an energy management system for microgrids

Energy Management Systems (EMS) are control schemes in charge of defining the optimal scheduling of dispatchable units in a microgrid. Output set points from the EMS could be exploited in other control loops that may benefit from the microgrids expected behavior improving their operation. In this context, this paper proposes a novel coupled operation of an EMS with an Adaptive Protection System (APS), such that the information of the EMS serves to compute the parameters of the protective devices deployed in a microgrid. This aspect is formalized in the present proposal based on already developed APS and EMS frameworks. To evaluate the performance of the proposal, the microgrid installed in Huatacondo, north of Chile, was used as a test-bed. The obtained results indicate that considering the information provided to the APS form the EMS improves the overall performance of the microgrid in case of failure, despite the operating conditions. This also indicates that moving towards an integrated design of the EMS and APS might enhance the behavior (robustness) of a microgrid (as a whole) in case of failures or contingencies.     

雷达高度表自动测试系统设计与实现

为优化基层部队高度表测试过程设计了1种新型自动测试系统,介绍了测试系统的总体设计思想、各模块工作原理,详细阐述各级电路的硬件实现方法和软件设计流程;以工控机和PCI总线为控制核心,通过高速数据采集卡和数字化仪对测试信号进行采集,独立完成所有信号调理PCB板卡和程控高度模拟器的设计,依托虚拟仪器的软件设计实现人性化人机交...     

高精度弹载压力测试系统的设计与改善

针对弹载压力测试过程中,传感器易受复杂多变的测试环境的影响从而导致测试结果与实际值偏差较大的问题,分析、设计了一套用于复杂环境温度下的高精度弹载压力测试系统,并对其进行了实验测试,将其测试结果与常规压力测试系统的输出进行了对比分析.结果证明该弹载压力测试系统的满量程最大相对误差为0.025 6,仅为常规压力测试最大误差...     

数字式保护虚拟测试仪的设计与实现

提出了一种新的数字式保护测试方法,基于虚拟测试仪实现对数字式保护原理和逻辑功能的测试。应用在产品研发阶段,与传统数字式保护测试方法相比,实现了测试数据的完全再现,具有灵活性、快速性、可追溯性。本文详细介绍了虚拟测试仪在数字式保护测试中的应用和基于LabVIEW虚拟测试仪的实现方法。     

数字式直流伺服系统性能测试系统设计

针对某数字式直流伺服系统维修调试需要,设计了一种基于单片机的性能测试系统。该系统以STC12C5A60S2单片机为处理器,构成主从式结构。从机按照测试方案控制伺服系统运行,主控机用于信号采集、处理与结果显示。该系统还扩展了CH375作为USB主机控制芯片,解决了数据空间不足与测试报告保存的问题。     

能量管理系统中一种基于XML的Web应用研究

随着Internet和电力市场的发展．能量管理系统(EMS)有了长足的进步。可扩展标记语言(XML)的出现及其技术的优势,使它可以成为EMS中Web服务的理想选择。为此,提出了一个在EMS中基于XML的Web应用系统框架,并在上述平台上重点探讨了如何将关系型数据转换成XML数据的方法。     

Design, simulation and testing of an EHV metal-encloseddisconnector

One of the most demanding design issues in the development of metal-clad disconnecters for application at 500 kV and over is to ensure the switching capabilities of the device. This paper presents the issues and processes involved from the initial design through to final testing of a 550 kV disconnector. The initial work concentrated on defining the design parameters in order to minimize the risk of arc breakout. Computer analysis using 2D and 3D modeling of the contact configuration was carried out. As a following step, before building the disconnector, the results of the computations were validated by a static test where the electrode arrangement was set manually at different gap distances and discharges between contacts were monitored. From the computational and test data a final contact design was optimized and a disconnector prototype was built. Finally the capabilities for bus-charging current switching were tested in accordance with the IEC 1259 standard. The results of these tests include measurement and comparison with EMTP simulations of the fast transient overvoltages generated by disconnector operations     

基于GPIB的自动测试系统设计

本系统设计的目的是组建某接收组件的自动测试平台.系统采用了虚拟仪器设计思想,主要设计方法为Visual c 面向对象设计及GPIB总线技术.本文首先介绍了GPIB总线结构的特点,然后阐述自动测试系统的组成及功能,并详细论述了系统软件的设计方法与思想,以及生成测试报表的方法.本系统可以实现对接收组件的实时监控、实验数据采集、数据的分析处理,以及报告生成等功能.利用虚拟仪器设计思想组建的自动测试系统提高了测试工作的效率、精确度,以及自动化程度,且结构灵活,扩展性好,因此具有良好的应用前景.     

Design of an ANN tuned adaptive UPFC supplementary damping controller for power system dynamic performance enhancement

A supplementary damping controller for a unified power flow controller (UPFC) is designed for power system dynamic performance enhancement. To maintain a good damping characteristic over a wide range of operating conditions, the gains of the UPFC supplementary damping controller are adapted in real time, based on online measured transmission line loadings (active and reactive power flows). To speed up the online gain adaptation process, an artificial neural network is designed. A major feature for the proposed adaptive UPFC supplementary damping controller is that only physically measurable variables (active and reactive power flows over the transmission line) are employed as inputs to the adaptive controller. To demonstrate the effectiveness of the proposed adaptive UPFC supplementary damping controller, computer simulations are performed on a power system subject to a three-phase fault. It is concluded from the simulation results that the proposed adaptive UPFC supplementary damping controller can yield satisfactory dynamic responses over a wide range conditions. The electromechanical mode with an oscillation frequency around 0.78 Hz has been effectively damped by the proposed damping compensators.     

96通道图像声纳测试系统的设计与实现

本文介绍了一种图像声纳测试系统的设计与实现。该型测试系统既可用于声透镜成像质量的分析,也可用于数字图像声纳波束形成质量的测试。该测试系统模拟部分共有96个通道,数字部分用7片DSP(TMS320C64×)芯片构成高速数据并行处理模块。声信号的原始数据或处理后的数据都可以用高速串行芯片传输至水面单元,经过对数据计算分析,可以获得声透镜成像的质量,或数字图像声纳波束形成的最佳参数。水池测试结果证明该测试系统实用便捷,性能稳定。     

基于动态测试技术的交流接触器性能评判系统

本文基于动态特性测试技术,开发交流接触器性能综合评判系统.针对交流接触器动态特性参数的数据特点,提出自适应模糊分级聚类方法,并以模糊分级聚类为基准,形成基于模糊聚类及神经网络的交流接触器综合性能评判系统.本文提出的理论与方法,对电器产品的研发样机与出厂产品检测,具有实际指导意义.     

传感器自动检测系统的设计与实现

为提高传感器的检测精度和检测效率,本文介绍了如何利用微计算机的硬件和软件改造老式传感器检测系统;讨论了灵敏系数、常温蠕变、机械滞后等传感器主要性能指标的检测方法;实现了传感器的性能检测、检测路数扩展和性能检测数据可视化等功能;并根据实际应用方面的需求,对程序进行了优化设计和改进,保证了传感器测试系统的功能实现和方便使用;最后探讨了传感器检测系统检测精度的提高方法.     

A/D转换器转换特性参数自动测试系统的设计

A/D转换器是许多电子系统中的一个重要器件,其性能好坏直接影响到整个系统的性能指标。本文介绍了一种自动测试系统,可对12位及12位以下的A/D转换器的转换特性进行测试。系统采用了模块化和开放式的设计方法,分别对各个模块进行优化设计,并且各个模块可以按需组合。文中重点介绍了该自动测试系统的硬件实现及系统调试。