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认知诊断计算机化自适应测验中的项目增补 被引量:27
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作者 陈平 辛涛 《心理学报》 CSSCI CSCD 北大核心 2011年第7期836-850,共15页
项目的增补对认知诊断计算机化自适应测验(CD-CAT)题库的开发与维护至关重要。借鉴单维项目反应理论(IRT)中联合极大似然估计方法(JMLE)的思路,提出联合估计算法(JEA),仅依赖被试在旧题和新题上的作答反应联合地、自动地估计新题的属性... 项目的增补对认知诊断计算机化自适应测验(CD-CAT)题库的开发与维护至关重要。借鉴单维项目反应理论(IRT)中联合极大似然估计方法(JMLE)的思路,提出联合估计算法(JEA),仅依赖被试在旧题和新题上的作答反应联合地、自动地估计新题的属性向量和新题的项目参数。研究结果表明:当项目参数相对较小且样本量相对较大时,JEA算法在新题属性向量和新题项目参数估计精度方面表现不错;而且样本大小、项目参数大小以及项目参数初值都影响着JEA算法的表现。 展开更多
关键词 认知诊断计算机化自适应测验 项目增补 在线标定 属性自动标识 新题
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Time-domain compressive dictionary of attributed scattering center model for sparse representation
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作者 钟金荣 文贡坚 《Journal of Central South University》 SCIE EI CAS CSCD 2016年第3期604-622,共19页
Parameter estimation of the attributed scattering center(ASC) model is significant for automatic target recognition(ATR). Sparse representation based parameter estimation methods have developed rapidly. Construction o... Parameter estimation of the attributed scattering center(ASC) model is significant for automatic target recognition(ATR). Sparse representation based parameter estimation methods have developed rapidly. Construction of the separable dictionary is a key issue for sparse representation technology. A compressive time-domain dictionary(TD) for ASC model is presented. Two-dimensional frequency domain responses of the ASC are produced and transformed into the time domain. Then these time domain responses are cutoff and stacked into vectors. These vectored time-domain responses are amalgamated to form the TD. Compared with the traditional frequency-domain dictionary(FD), the TD is a matrix that is quite spare and can markedly reduce the data size of the dictionary. Based on the basic TD construction method, we present four extended TD construction methods, which are available for different applications. In the experiments, the performance of the TD, including the basic model and the extended models, has been firstly analyzed in comparison with the FD. Secondly, an example of parameter estimation from SAR synthetic aperture radar(SAR) measurements of a target collected in an anechoic room is exhibited. Finally, a sparse image reconstruction example is from two apart apertures. Experimental results demonstrate the effectiveness and efficiency of the proposed TD. 展开更多
关键词 attributed scattering center model parameter estimation DICTIONARY time domain
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