智能搜索引擎如何应用WEB信息挖掘技术

介绍网络信息挖掘技术定义、关键技术，以Google为例，剖析网络信息挖掘技术在搜索引擎的应用。智能搜索引擎如何应用WEB信息挖掘技术进行个性化服务。     

基于样本加权的文本聚类算法研究

样本加权聚类算法是一种最近才引起人们注意的算法,还存在一些需要解决的问题,例如,聚类对象之间的结构信息对样本加权聚类是否有帮助,如何将结构信息自动转换为样本或对象的权重?针对该问题,本文以学术论文为聚类对象,以K-Means算法为聚类算法基础,利用论文之间的引用关系计算每篇论文的PageRank值,并将其作为权重,提出一种基于样本加权的新的文本聚类算法.实验结果表明,基于论文PageRank值加权的聚类算法能改善文本聚类效果.该算法可推广到网页的聚类中,利用网页的PageRank进行加权聚类,来改善网页的聚类效果.     

体育统计中的几个重要概念及其作用

对统计总体、随机样本、统计变异以及统计距离等概念的内涵及其在体育统计中的应用进行深刻剖析,认为只有切实领会统计学的基本概念,抓住统计思想及其本质,才能真正提高体育工作者的统计水平。     

浅谈乡镇面对食糖市场价格低迷的对策--云南昌宁县更戛乡甘蔗产业发展现状个案分析

对云南省昌宁县一个乡的甘蔗及甘蔗农特税被取消后的复杂形势进行分析，进而提出促进农民增收和广大农村的全面建设小康社会步伐的相应对策。     

又向荒唐演大荒──《红楼梦》幻曲结构析说

运用结构主义手法,分析《红楼梦幻曲》结构的特征,指出其中所揭示的全书主旨是揭露无情无爱的现实人生,以及十二钗各自命运与结构主题的呼应。     

A RAPID FUZZY RULE EXTRACTION METHOD FOR FUZZY CONTROLLER

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利用分光光度法检测生活饮用水中的氰化物

用分光光度计测出不同浓度KCN反应溶液的吸光度,绘制出标准工作曲线。将待测水样在酸性条件下进行蒸馏,取蒸馏液使之与氯胺T、异烟酸－巴比妥酸试剂反应,比色分析,定性判断水样中是否含有氰化物;再用分光光度计测出其吸光度,在标准工作曲线上查值,经过计算即可行出水样中氰化物的含量。     

The Benefits of Fixed Item Parameter Calibration for Parameter Accuracy in Small Sample Situations in Large‐Scale Assessments

Large‐scale assessments such as the Programme for International Student Assessment (PISA) have field trials where new survey features are tested for utility in the main survey. Because of resource constraints, there is a trade‐off between how much of the sample can be used to test new survey features and how much can be used for the initial item response theory (IRT) scaling. Utilizing real assessment data of the PISA 2015 Science assessment, this article demonstrates that using fixed item parameter calibration (FIPC) in the field trial yields stable item parameter estimates in the initial IRT scaling for samples as small as n = 250 per country. Moreover, the results indicate that for the recovery of the county‐specific latent trait distributions, the estimates of the trend items (i.e., the information introduced into the calibration) are crucial. Thus, concerning the country‐level sample size of n = 1,950 currently used in the PISA field trial, FIPC is useful for increasing the number of survey features that can be examined during the field trial without the need to increase the total sample size. This enables international large‐scale assessments such as PISA to keep up with state‐of‐the‐art developments regarding assessment frameworks, psychometric models, and delivery platform capabilities.     

Posttraumatic stress avoidance symptoms as mediators in the development of alcohol use disorders after exposure to childhood sexual abuse in a Swiss community sample

This study examined the role of posttraumatic stress disorder (PTSD) symptoms of re-experience, avoidance, and hyperarousal in the relationship between different types of trauma and alcohol use disorders (AUD). We used data from 731 trauma-exposed individuals who participated in the first wave of the PsyCoLaus-study. Trauma characteristics were assessed relatively to the occurrence of lifetime PTSD symptoms and AUD. The results suggest that lifetime and childhood sexual abuse as well as overall childhood trauma were directly linked to AUD and PTSD symptoms, in particular to avoidance symptoms. From single symptom clusters PTSD avoidance was found to specifically mediate the trauma-AUD pathway. Both childhood and sexual trauma strongly contribute to the comorbidity of PTSD and AUD and avoidance-type symptoms appear to play a central role in maintaining this association. Hence, the alleviation of avoidance symptoms might be an important target for therapeutic intervention among victims of sexual abuse before specific addiction treatment is initiated.     

石墨烯基固相微萃取涂层的制备及其对多溴联苯的检测

采用直接涂层的方法将石墨烯纳米材料均匀地涂布在铜丝表面制得了石墨烯基固相微萃取涂层纤维,结合固相微萃取-气相色谱-电子捕获检测器(SPME-GC-ECD)技术,建立了对水中多溴联苯(PBBs)的直接测定方法。实验优化了萃取时间、萃取温度、离子强度等固相微萃取条件。在优化的条件下,该方法在20-2000ng·L-1的范围内表现出了良好的线性,检出限为5.2-10.2ng·L-1;单个纤维间和纤维与纤维间的精密度分别为4.84-9.96%和8.3-12.4%。纤维对环境样品中PBBs加标2滋g·L-1的回收率为94.5-111%。该方法简单、快速、灵敏,可实现多溴联苯的快速检测。