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排序方式: 共有112条查询结果,搜索用时 31 毫秒
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Gini指数可用来描述分布的不均匀性,已广泛应用于决策树算法,本文开发了基于Gini指数的认知诊断计算机化自适应选题策略,并在饱和模型和缩减模型下与SHE, MPWKL,GDI,PWKL选题策略进行比较。模拟研究表明,基于Gini指数的选题策略与SHE,MPWKL,GDI相比,分类精度相近并提高了题库的利用率;与PWKL相比,提高了分类的精度和选题速度,综合来看,基于Gini指数的选题策略能够兼顾分类精度和题库使用均匀性。  相似文献   
94.
陈平 《心理学报》2016,48(9):1184-1198
在线标定技术由于具有诸多优点而被广泛应用于计算机化自适应测验(CAT)的新题标定。Method A是想法最直接、算法最简单的CAT在线标定方法, 但它具有明显的理论缺陷--在标定过程中将能力估计值视为能力真值。将全功能极大似然估计方法(FFMLE)与“利用充分性结果”估计方法(ECSE)的误差校正思路融入Method A (新方法分别记为FFMLE-Method A和ECSE-Method A), 从理论上对能力估计误差进行校正, 进而克服Method A的标定缺陷。模拟研究的结果表明:(1)在大多数实验条件下, 两种新方法较Method A总体上可以改进标定精度, 且在测验长度为10的短测验上的改进幅度最大; (2)当CAT测验长度较短或中等(10或20题)时, 两种新方法的表现与性能最优的MEM已非常接近。当测验长度较长(30题)时, ECSE-Method A的总体表现最好、优于MEM; (3)样本量越大, 各种方法的标定精度越高。  相似文献   
95.
CD–CAT中已有选题策略较注重测验效率,而对题库使用率不够重视。针对此问题,基于DINA模型,引入两种新的选题策略KLED和RHA,同时对HA进行模拟研究。结果显示:PWKL与KLED只在测验效率上具有优势;KLED若按属性向量分层,题库使用率有所提高,KLED比ED更容易推广到其他有显式表达的诊断模型场合;HA、RHA和RP–PWKL可较好兼顾测验效度和题库使用率,但RP-PWKL需设置项目的最大曝光率阈值。两种新选题方法在定长和变长CD-CAT都具有一定的应用价值。  相似文献   
96.
Brock J  Norbury C  Einav S  Nation K 《Cognition》2008,108(3):896-904
It is widely argued that people with autism have difficulty processing ambiguous linguistic information in context. To investigate this claim, we recorded the eye-movements of 24 adolescents with autism spectrum disorder and 24 language-matched peers as they monitored spoken sentences for words corresponding to objects on a computer display. Following a target word, participants looked more at a competitor object sharing the same onset than at phonologically unrelated objects. This effect was, however, mediated by the sentence context such that participants looked less at the phonological competitor if it was semantically incongruous with the preceding verb. Contrary to predictions, the two groups evidenced similar effects of context on eye-movements. Instead, across both groups, the effect of sentence context was reduced in individuals with relatively poor language skills. Implications for the weak central coherence account of autism are discussed.  相似文献   
97.
人类精子库伦理管理的困惑与对策   总被引:1,自引:0,他引:1  
建立人类精子库主要用于解决不孕不育问题,在一定程度上解决了男性不育的难题,拓展了生殖医学及发育生物学领域,为许多不孕不育夫妇带来了福音,具有广泛的科学及社会学意义。但是,冷冻精子的使用所涉及的医学、人文、法律、伦理、道德等问题已成为严肃的值得深思熟虑的社会问题。如不加以规范和管理,必将对人类及整个社会造成危害。  相似文献   
98.
Do economic indicators predict the general level of support for gender equality? This question was investigated in a sample of countries in Central and Eastern Europe, a region that has been undergoing rapid economic changes since the early 1990s. In this overall sample of male and female college students from ten countries, including the United States as a comparison, the predicted association between stronger beliefs in gender role egalitarianism and positive economic factors was generally supported. Also, consistent with other research, women were more in support of gender equality than men were. There was no support for a predicted trend in less support for gender equality over the time period of the present study.  相似文献   
99.
This paper compared three different procedures common in infant speech perception research: a headturn preference procedure (HPP) and a central-fixation (CF) procedure with either automated eye-tracking (CF-ET) or manual coding (CF-M). In theory, such procedures all measure the same underlying speech perception and learning mechanisms and the choice between them should ideally be irrelevant in unveiling infant preference. However, the ManyBabies study (ManyBabies Consortium, 2019), a cross-laboratory collaboration on infants’ preference for child-directed speech, revealed that choice of procedure can modulate effect sizes. Here we examined whether procedure also modulates preference in paradigms that add a learning phase prior to test: a speech segmentation paradigm. Such paradigms are particularly important for studying the learning mechanisms infants can employ for language acquisition. We carried out the same familiarization-then-test experiment with the three different procedures (32 unique infants per procedure). Procedures were compared on various factors, such as overall effect, average looking time and drop-out rate. The key observations are that the HPP yielded a larger familiarity preference, but also reported larger drop-out rates. This raises questions about the generalizability of results. We argue that more collaborative research into different procedures in infant preference experiments is required in order to interpret the variation in infant preferences more accurately.  相似文献   
100.
The aim of this study is to investigate the working memory (WM) of very-low-birthweight (VLBW, ≤ 1500 g) children at the age of 11 years using Baddeley’s WM model. A regional cohort of 95 VLBW children was assessed for the domains of the WM model (central executive [CE], visuospatial sketchpad [VS], and phonological loop [PL]) using subtests from the Working Memory Test Battery for Children (WMTB-C) and the Wechsler Intelligence Scale for Children – Fourth Edition (WISC-IV). VLBW children were categorized into three groups according to their degree of brain pathology (normal, minor, or major) in neonatal brain magnetic resonance imaging at the term age, and the WM performance was compared between groups to test norms. The structure of the WM model was studied by analyzing correlations among domains. Even VLBW children with normal cognitive development (general ability index ≥ 85) performed worse compared to the test norms (M = 100, SD = 15) on CE (M = 87.64, SD = 20.54, < .001) and VS (M = 91.65, SD = 11.03, p < .001), but their performance on PL was above the norm (M = 110.79, SD = 13.79, p < .001). VLBW children with major brain pathology performed significantly worse on VS and PL compared to the other groups. The correlations among the WM domains of the VLBW children differ from earlier findings in normative populations. To conclude, the WM of the VLBW children in the study differ—especially in the CE and VS subtest scores—from the normative population irrespective of the degree of brain pathology and level of cognitive development.  相似文献   
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