一种支持分类数据源查找的语义覆盖网络   总被引：1，自引：0，他引：1  

乔百友  王国仁  谢可心 《东南大学学报》2007,23(3):322-326

针对使用分类层次来描述数据语义的分布式数据源,提出了一种支持数据共享的基于super-peer的语义覆盖网络SSON.SSON能够根据数据的语义,动态地将peer划分成多个语义簇,语义簇之间组织成语义覆盖网络.每个语义簇由一个super-peer和一组peer组成,仅负责回答其语义子空间上的查询.查询首先根据其语义被路由到适合的语义簇中,然后被转发给包含结果的peer.同时给出了相关的算法,并进行了实验研究,实验结果表明,SSON具有良好的可扩展性,并在查找性能和代价之间取得了一个良好的折中.  相似文献   

A STUDY ON ENGLISH READING PROFICIENCY OF STUDENTS IN COLLEGE     

顾敏 《读与写:教育教学刊》2008,5(10)

The study attempted to investigate the mean level of the participants' reading proficiency and identify what levels of reading comprehension questions (literal,reorganization and inferential)the participants are able to answer. A written reading comprehension test wag administered. The participants consisted of 45 students enrolled in college English class. The data obtained from a written reading comprehension test,a background questionnaire,and a structured interview which was analyzed by using SPSS. The results indicated that the participants' mean level of reading proficiency Was below the standard.  相似文献   

DNA条形码在原生动物系统分类学中的应用     

王绍彬  唐发辉  赵元莙 《教育教学论坛》2019,(7):158-159

DNA条形码技术是利用目的基因中一段标准的、有足够变异的且相对较短的DNA序列来进行物种快速与准确鉴定的一种分子生物学技术。DNA条形码技术历经十几年的发展,在动物、植物和微生物等领域的物种分类和鉴定研究中得到应用。本文从DNA条形码的概念和特点、DNA条形码在原生动物系统分类学研究中的应用等方面进行了综合介绍,以期拓展中小学生的知识面,促进中小学素质教育的发展。  相似文献   

沿阶草亚科植物的叶表皮特征及其在分类学上的意义   总被引：1，自引：0，他引：1  

戴伦凯  梁松筠 《中国科学院研究生院学报》1991,29(4):335-346

本文用扫描电镜和光学显微镜观察研究了沿阶草亚科(Ophiopogonoideae)3属39种1变种叶   片远轴面的表皮特征。认为这些气孔器周围的邻近细胞和表皮细胞特征在分类上有比较重要的意义，  主要是：(1)有助于沿阶草属、山麦冬属和球子草属种间和属间种类的鉴别；(2)给这些植物类群的分类提供了有用的性状；(3)对沿阶草属的归类有着比较重要的意义；(4)为探讨沿阶草亚科内3个属间的亲缘关系提供了有益的证据。并认为，这三个属的气孔器邻近细胞和表皮细胞特征的演化趋势为无气孔带类型→无角质突起类型→具角质突起类型(具气孔带)。根据这些特征和外部形态性状认为这三个属 的亲缘关系比较密切，应归属于同一个大类群—沿阶草亚科。  相似文献   

应用数量分类探讨鹅观草属的归属问题     

陈守良  徐克学 《中国科学院研究生院学报》1989,27(3):190-196

研究全世界鹅观草属只Roegneria C．Koch中绝大多数种类与其有关属(冰草属、披碱草 属、偃麦草属及赖草属)的外部形态、解剖、细胞等30个性状，应用相关系数抑或距离系数以及各种聚类方法组合所得出的树系图，均明确显示鹅观草属应归入披碱草属。  相似文献   

中国萱草属数量分类研究   总被引：1，自引：0，他引：1  

熊治廷  陈心启  洪德元 《中国科学院研究生院学报》1997,35(4):311-316

用聚类分析和主成分分析研究了国产萱草属11个类群的分类。结果发现这些类群形成4簇。第一簇：北黄花菜、黄花菜、小黄花菜和多花萱草。第二簇：小萱草和大苞萱草。第三簇：折叶萱草，西南萱草和矮萱草。第四簇：萱草及其三倍体类型。各簇都有其区别特征。讨论了簇内各类群之间的亲缘关系及属下分组问题。  相似文献   

组织中的知识冲突研究   总被引：4，自引：0，他引：4  

张钢  倪旭东 《科学学与科学技术管理》2007,28(1):106-110

随着知识资源在企业价值创造过程中的地位和作用日益突出，根源于知识异质性的冲突在企业组织中变得越来越普遍，这就迫切需要有一个跨越知识管理和冲突管理的全新的知识冲突管理框架来应对这一问题。从组织中的知识类型分析入手，探讨了知识冲突的根源、类型和过程，以期为组织中知识冲突的分析及管理提供新的理论框架。  相似文献   

浙江省薯蓣科植物的数量分类研究     

奚镜清  毛宗秀  杨建伟  奚可椿 《中国科学院研究生院学报》1990,28(6):442-451

以浙江省薯蓣科全部植物——薯蓣属17种和1变种为18个分类单位，以形态为主兼顾组织结构、化学成分及地理分布，列出72项性状，对这些植物进行了数量分类。用最短距离法、最长距离法、中间距离法甲、中间距离法乙、重心法、类平均法以及离差平方和法的系统聚 类，探索了这些植物彼此间的亲缘关系，认为以前对它们的经典分类处理基本合理。由于”薯莨”性状明显特殊，建议成立新组——薯莨组。  相似文献   

Using the taxonomy of cognitive learning to model online searching     

Bernard J. Jansen  Danielle Booth  Brian Smith   《Information processing & management》2009,45(6):643-663

In this research, we investigated whether a learning process has unique information searching characteristics. The results of this research show that information searching is a learning process with unique searching characteristics specific to particular learning levels. In a laboratory experiment, we studied the searching characteristics of 72 participants engaged in 426 searching tasks. We classified the searching tasks according to Anderson and Krathwohl’s taxonomy of the cognitive learning domain. Research results indicate that applying and analyzing, the middle two of the six categories, generally take the most searching effort in terms of queries per session, topics searched per session, and total time searching. Interestingly, the lowest two learning categories, remembering and understanding, exhibit searching characteristics similar to the highest order learning categories of evaluating and creating. Our results suggest the view of Web searchers having simple information needs may be incorrect. Instead, we discovered that users applied simple searching expressions to support their higher-level information needs. It appears that searchers rely primarily on their internal knowledge for evaluating and creating information needs, using search primarily for fact checking and verification. Overall, results indicate that a learning theory may better describe the information searching process than more commonly used paradigms of decision making or problem solving. The learning style of the searcher does have some moderating effect on exhibited searching characteristics. The implication of this research is that rather than solely addressing a searcher’s expressed information need, searching systems can also address the underlying learning need of the user.  相似文献   

Geography tests in the Finnish Matriculation Examination in paper and digital forms – An analysis of questions based on revised Bloom’s taxonomy     

《Studies in Educational Evaluation》2020

This study examines the possible change in cognitive processes and geographical knowledge requirements during the digitalisation process of the Finnish Matriculation Examination in Geography (digitalised in the autumn of 2016). The theoretical background is derived from revised Bloom’s taxonomy, which is applied as a framework for the content analysis of the questions (n = 331) of the geography tests between the autumn of 2013 and the spring of 2019. The results show that the questions mainly require an understanding of conceptual and factual knowledge. Because of the digitalisation, questions that require remembering have been reduced, whereas questions that require analysing have been increased. In addition, more comprehensive use and more extensive production of materials are required in the tests. Based on our research findings, we emphasise the need for a careful re-evaluation of the kind of cognitive processes and knowledge that should be assessed in geography tests, both nationally and internationally.  相似文献