电脑验光与检影验光的比较

近年来,随着国内外采用电脑验光仪进行验光的日益普及,其临床实用价值需进一步验证。为了进一步比较电脑验光与传统公认的客观检影验光的准确性,我们采用两种方法,对部分近视屈光不正患者,进行了屈光测量,并对其结果作了对比分析,现报告如下:

验光仪的不确定度分析

按照验光标准的要求,提出了验光仪不确定度的计算方法。通过仪器示值和验光仪验光镜片的的顶焦度测量误差的具体测量方法,得出计算平均值,平均值与模拟眼的标定值比较,并分析了该方法的不确定度,可指导实践的验光工作。

Reducing Item Exposure in Computerized Adaptive Testing Systems Using Automatic Item Generation

This paper studies the technics of reducing item exposure by utilizing automatic item generation methods. Known test item calibration method uses item parameter estimation with the statistical data, collected during examinees prior testing. Disadvantage of the mentioned item calibration method is the item exposure; when test items become familiar to the examinees. To reduce the item exposure, automatic item generation method is used, where item models are being constructed based on already calibrated test items without losing already estimated item parameters. A technic of item model extraction method from the already calibrated and therefore exposed test items described, which can be used by the test item development specialists to integrate automatic item generation principles with the existing testing applications.