The Design And Realization Of Distributed Network Examination System Based On The IRT

With the rapid development of computer technology and network technology, computation technology is shifting gradually from an integrated environment to a distributed environment, and the computer-based test software today tends to change into a distributed examination system rather than the single-unit version earlier, and the traditional test pattern follows the trend of Computer Auto-adaptation Test(referred as CAT). The principle of traditional computer testing system is to group the test questions into one examination paper, and the candidates will answer the questions on the computers. All the test questions are set up in advance in this test system. In contrast, CAT system can determine which questions are most suitable for a particular examinee by judging their aptitudes from their reaction to the questions.It is a constant and rough task for the society to improve the validity, utility and correctness of our educational test system as the practical means of evaluating one's capability. Most CAT tests employ a set of statistical framework based on Item Response Theory (IRT) to choose testing items and to score the responses of the candidates.In this paper I adopt a three-parameter Logistic model as the basic model for the research and design of DNES based on IRT.Firstly, the related theories and key technologies of CAT system are introduced, among which are the theory and mathematical model of CTT and IRT, and the analysis of some calculation methods of some parameters that should be resolved in these models. And the second section is a detailed introduction of the theory basis regarding the distributed application software technology, including software format, DCOM technology, CORBA technology, EJB technology, MIDAS Principle etc., discussing the approach of establishing the multi-layered MIDAS Distributed C/S software based on Delphi framework. Thirdly, according to the above theories, a distributed examination system, an IRT-based network, is developed. And finally,some key technical details involved in the actual process are described, e.g. the initialization and termination conditions, the principle of question selection, test termination conditions, Item Pool Management, access of questions, Test Equating, item equivalency etc., as well as some assumptions for improving the potential problems.