7_知识管理_RDFppt课件

1、1知识管理Knowledge Management李海生Li_haisheng163 .2课程邮箱btbukm126PWD：12345678.3与知识管理相关的Topic信息检索 Information Retrieval知识工程 Knowledge Engineering语义网 Semantic Web本体 Ontology资源描画框架 Resource Description Framework本体描画言语 Ontology Web Language知识网格 Knowledge Grid面向效力的架构 Service-Oriented Architecture知识管理成熟度模型 Knowl

2、edge Management Maturity Model (K3M)知识管理案例.知识管理规范知识管理规范国家规范GB/T 23703.1欧洲规范澳大利亚国家规范加拿大国家规范英国国家规范美国APQC规范美国消费力与质量中心American Productivity and Quality Center4.知识管理国家规范框架术语组织文化知识活动实施指南评价5.知识管理业务流程知识管理成熟度模型K3M知识管理评价模型6.7上次课程内容回想元数据召回率Recall检索出的相关文档数和文档库中一切的相关文档数的比率衡量的是搜索引擎的查全率 精度Precision 检索出的相关文档数与检索出的文

3、档总数的比率 衡量的是搜索引擎的查准率.8语义Web语义Web的根底架构Tim Berners-Lee，2000 .语义网书籍引荐9.语义网书籍引荐10.11元数据表示言语 标志言语 规范通用标志言语SGML超文本标志言语HTML可扩展标志言语XML虚拟现实模型言语VRML无线标志言语WML元数据规范 Dublin Core HL7描画医学网络资源的元数据 教育资源元数据 机读目录MARC .12XML 性质W3C于1998年2月发布的一种规范 是SGML的一个简化子集 可扩展标志言语 特点较好地处理了HTML无法表达数据内容等问题允许各个组织、个人建立适宜本人需求的标志集合 .13XML与H

4、TML比较文档的3个要素数据、构造以及显示方式 HTML 显示方式内嵌在数据中 在创建文本时，要时时思索输出格式 创建文档的反复任务量大 不易抽取语义信息 XML显示格式从数据内容中独立出来，保管在款式单文件(Style Sheet)中 自我描画性质可以很好地表现许多复杂的数据关系 .14XML构造 文件头 与HTML类似，是可选的文件主体 包括一个或多个元素 方式是一棵分级的树 混杂的“结尾部分 由注释、处置指令和空白组成 注释用表示，可在文档中恣意位置 .15元素(Element) 表示方法由开场标志、终了标识以及标识之间的数据构成 标志之间的数据被以为是元素的值 每个元素都有不同的标志名

5、王力元素名是director 元素值是“王力 王力 元素名是actor元素值是“王力.16元素要点关键的3点 一切元素必需有终了标志 一切元素必需正确嵌套，不允许交迭 一切属性值必需加引号 留意点XML文档主体有且仅有一个XML根元素 可以嵌套XML元素，构成一棵树形构造 .17XML文档例子 数据构造 许卓群等 数据发掘 韩家炜等 .18例子的树状构造 .19XML属性 给元素提供进一步的阐明信息 必需出如今起始标志中 以称号/取值对出现，属性名不能反复称号与取值之间用等号“=分隔用引号把取值引起来 例如 100000阐明了工资的货币单位是人民币元 .20XML处置器 目的解析XML文档提供

6、对XML文档内容和构造的访问 文档对象模型(Document Object Model，DOM)将完好的XML转换成一棵树的方式放在内存中 供随机访问元素、属性 XML简单API(Simple API for XML，SAX) 采用事件驱动模型 经过标志的起止来触发事件 DOM与SAX的比较讨论.21处置指令(Processing Instruction) 目的给XML处置器提供信息，使其可以正确解释文档内容 表示起始标志是“ 方法XML分析器把这些信息原封不动地传给运用程序 由运用程序来解释这个指令 遵照它所提供的信息进展处置 .22两种处置指令XML声明 必需包括version属性，指明所

7、采用的XML的版本号，而且它必需在属性列表中排在第一位standalone属性阐明该XML文档能否和一个外部文档类型定义DTD配套运用 encoding属性那么指明了数据所采用的编码规范 XSL款式单援用 通知XSL款式单解析器，款式单的类型是text-xsl 类型text-xsl可以在文档contacts.xsl中找到 .23XML的名字空间 背景由于XML对互操作性的支持，每个人都可以创建属于本人的XML词汇 不同的开发者会用一样的元素来代表不同的实体 作用为XML文档元素提供了一个上下文 允许开发者按一定的语义来处置元素 为什么引入NS(命名空间)讨论.24XML NS 例子?xml v

8、ersion=1.0?hamburgersxmlns:purchase=/franchise/pricesxmlns:sales=/customer/priceshamburger lowfat=dream onnameCowBurger/namedescriptionGreasy and good./descriptionpurchase:price0.99/pricesales:price2.99/price/hamburger/hamburgers.25XSL(Extensible Stylesheet Language) 背景用规范的DO

9、M API来实现XML数据的交互，是非常单调乏味的 如想找到一切满足某些条件的元素，或转换为简单的HTML表格，必需手工书写代码遍历整棵树来寻觅 目的为规范化及简化人们完成这些义务所需做的任务 .26食品的例子 XML文档 月饼 中秋节食用的传统食品 2.99 HTML文档 食品 月饼, 中秋节的传统 食品, 2元 .27XSL文件 选取了当前结点的一切食品子结点 hamburgers 标识出符合给定条件的结点 , , 取结点中各个元素的值 .28XSL用途加强了互操作性 XML数据转换为HTML从一种XML格式到另一种XML格式之间的转换 开发人员不用为了描画某种类型的数据而采用通用的词汇某

10、个人向他的系统发送了一篇XML文档，而他的系统不认识它所采用的XML词汇只需进展一次简单的XSL转换就可以得到本人熟习的词汇 .29文档类型定义 DTD 目的定义XML文档构造，即其中的元素、属性以及元素之间关系的 定义了文件中的元素能用什么名字，能放在什么位置，应该怎样组合 可以检测XML文档的构造能否正确 例如描画一组，其中每个又可以包含假设干个DTD中应该有语句: 生成的表 ：管乐弦乐器乐 .30DTD 援用内部援用包含在XML文档的前导阐明部分 如 文档体外部援用作为一个外部文档被援用 如 文档体SYSTEM指一个作者或组织所编写的通用的DTD 或是 PUBLIC 指由权威机构制定的、

11、提供应特定行业或公众运用的DTD .31DTD中ETD(元素类型声明)作用声明一切有效的文档元素 构造 类型 空元素类型 运用空元素标志，元素中没有内容 ANY元素类型 元素中可以包含任何内容 父元素类型 元素中可以包含子元素在DTD中经过正那么表达式规定子元素出现的顺序和次数 混合元素类型 元素中可以包含文本文本之间可以有选择地插入子元素，子元素出现的顺序和次数不受限制 .32XML Schema DTD缺陷 采用了非XML的语法规那么不支持数据类型扩展性较差 XML方式己经渐有取代DTD的趋势拥有比DTD更强大的功能 用于更准确和有效地描画XML文档构造.33XML方式的优点一致性直接借助

12、XML本身的特性利用XML的根本语法规那么定义XML文档的构造 不用再利用一种特定的方式化的言语扩展性 引入了数据类型、命名空间在根本数据类型根底上用户可本人扩展数据类型 互换性 利用方式可以书写XML文档并验证文档的合法性 对不同的方式进展转换，以实现更高层次的数据交换 规范性 利用元素的内容和属性来定义XML文档的整体构造 基于XML，更具有规范性 .34数据类型 用途为Element Type和Attribute Type指定数据类型 根本数据类型 10种)entity，entities，enumeration，id，idref，idrefs，nmtoken，nmtokens，notat

13、ion和string 扩展数据类型 bin.baSe64，bin.heX，boolean，char，date，dateTime，dateTime.tz，fixed.14.4，float，int，number，timetime.tz，i1 ，i2, i4，r4, r8，ui1, ui2，ui4, uri，uuid .35XMLS元素类型根本格式 取值及含义 (略.36XMLS属性类型根本格式 取值及含义 (略.37数据类型的运用例子1定义元素“名字和“生日 其中string和date类型都是Schema中自带的根本数据类型 minOccurs和maxOccurs是最少和最多出现次数的约束，这里表

14、示有而且只出现一次 .38数据类型的运用例子2扩展数据类型Schema中没有规定的类型，如“性别类型 定义例子 注释name属性是该数据类型的称号 数据类型由restriction子元素进展约束该元素中的base属性是基类型 .39元数据自动抽取技术 预处置 剔除在格式、内容、言语等方面存在问题或严重缺失的文档 产生格式相对规整的文本文档 提取元数据 由数字化文档元数据的规范定义，产生提取元数据的各种方式 根据元数据方式进展数字化文档的发掘与匹配 利用与数字化文档相关的启发式规那么和阅历规那么，有效提取元数据 .40MathML含义Mathematical Markup Language用途用

15、来描画数学符号、纪录其构造和内容目的是在Web上实现能像HTML处置文本一样，处置数学问题 .41例：x2 + 4x + 4 =0 applyplus/applypower/cix/cicn2/cn/applyapplytimes/cn4/cncix/ci/applycn4/cn/apply.42SMIL含义Synchronized Multimedia Integration Language用途一种基于XML的表述多媒体演示的言语 将一组独立的多媒体对象整合为一个多媒体演示 .43SMIL例子HTMLHEADSTYLE.time behavior:url(#default#time); /

16、STYLE/HEADBODYDIV CLASS=time t:timeline=seqP class=time t:dur=1 This appears for one second and goes away/P P class=time t:dur=1 This appears after one second, remains visible for one second and goes away /PP class=time t:dur=1 This appears after two seconds, remains visible for one second and goes

17、away /P/DIV/BODY/HTML.44CDF 含义Channel Definition Format 一种开放的规格允许Web的发布者经常更新信息或是频道 CDF起到了频道内容目录的作用用户仅需选择一下频道 信息就会从Web效力器定时的传送到客户端 .45资源描画言语RDF.46资源描画框架言语RDF采用元数据来索引网络上的信息运用RDFResource Description Framework来描画元数据以及元数据之间的关系元数据是“关于数据的数据，是用来描画网络资源的数据。RDF是处置元数据的根底，它为在运用程序之间交换机器可了解的网络数据提供了可互操作性。.47RDF的运用领

18、域RDF可以运用在很多领域中在资源发现中，RDF可以加强搜索引擎语义处置才干在编目领域中，RDF可以用来描画某个网站、网页之间或者数字图书馆中的内容及内容之间的关系采用RDF的智能主体Agent可以提高机构之间知识共享和交换的才干.48RDF的作用?RDF (Resource Description Framework)来描画元数据以及元数据之间的关系长江的XML描画文档 6300 kilometers western Chinas Qinghai-Tibet Plateau East China SeaHere is data about the Yangtze River. It has

19、a length of 6300 kilometers.Its startingLocation is western Chinas Qinghai-Tibet Plateau. Its endingLocationis the East China Sea.49XML - RDF 6300 kilometers western Chinas Qinghai-Tibet Plateau East China SeaXML将XML文档修正为有效的RDF文档: 6300 kilometers western Chinas Qinghai-Tibet Plateau East China SeaRD

20、FYangtze.xmlYangtze.rdfconvert to.50RDF格式 6300 kilometers western Chinas Qinghai-Tibet Plateau East China SeaRDF provides an ID attribute for identifying the resource being described. The ID attribute is in the RDF namespace.Add the fragment identifier symbol to the namespace.123.51RDF格式 (cont.) 630

21、0 kilometers western Chinas Qinghai-Tibet Plateau East China SeaIdentifies the type(class) of the resource being described.Identifies the resource being described. Thisresource is an instance of River.These are properties,or attributes, of thetype (class).Values of the properties1234.52命名规那么xmlns=ge

22、/river#Question: 为什么在命名空间后放置 #? E.g.,Answer: RDF is very concerned about uniquely identifying things - uniquely identifying the type (class) and uniquely identifying the properties.If we concatenate the namespace with the type then we get a uniqueidentifier for the type, e.g.,/ri

23、ver#RiverIf we concatenate the namespace with a property then we get a uniqueidentifier for the property, e.g.,/river#/river#startingL/river#endingLocationThus, the # symbol is simply a mechanism for separating the namespace from the type name and the pr

24、operty name.Best PracticeBest Practice.53RDF格式 value value .54运用RDF格式的益处The RDF format, if widely used, will help to make XML more interoperable:Tools can instantly characterize the structure, this element is a type (class), and here are its properties.RDF promotes the use of standardized vocabulari

25、es . standardized types (classes) and standardized properties.The RDF format gives you a structured approach to designing your XML documents. The RDF format is a regular, recurring pattern.It enables you to quickly identify weaknesses and inconsistencies of non-RDF-compliant XML designs. It helps yo

26、u to better understand your data!You reap the benefits of both worlds:You can use standard XML editors and validators to create, edit, and validate your XML.You can use the RDF tools to apply inferencing to the data.It positions your data for the Semantic Web!Network effectInteroperability.55运用RDF格式

27、的缺陷受限制：在设计XML文件时遭到RDF格式的约束.RDF运用命名空间来独一识别类(types /classes), 属性和资源。要求对命名空间有准确的了解。必需掌握RDF格式的语法。.56独一识别资源Earlier we said that RDF is very concerned about uniquely identifying the type (class) and the properties. RDF is also very concerned about uniquely identifying the resource, e.g., 6300 kilometers w

28、estern Chinas Qinghai-Tibet Plateau East China SeaThis is the resource being described. We want to uniquelyidentify this resource.57rdf:IDThe value of rdf:ID is a relative URI.The complete URI is obtained by concatenating the URL of the XML document with # and then the value of rdf:ID, e.g., 6300 ki

29、lometers western Chinas Qinghai-Tibet Plateau East China SeaSuppose that this RDF/XML document is located at this URL: /geography/rivers.Thus, the complete URI for this resource is:Y/geography/rivers#Yangtze.58xml:baseOn the previous slide we showed how the URL of the doc

30、ument provided the base URI.Depending on the location of the document is brittle: it will break if the document is moved, or is copied to another location.A more robust solution is to specify the base URI in the document, e.g., 6300 kilometers western Chinas Qinghai-Tibet Plateau East China SeaResou

31、rce URI = concatenation(xml:base, #, rdf:ID) = concatenation(/geography/rivers, #, Yangtze) = /geography/rivers#Yangtze.59rdf:about不运用相对的URI，而是用rdf:about 标识出完好的资源URI。 6300 kilometers western Chinas Qinghai-Tibet Plateau East China Sea.60RDF三元组-资源/属性/值/geography/rivers#Yang

32、tze has a /river#length of 6300 /geography/rivers#Yangtze has a /river#startingLocation of western Chinas ./geography/rivers#Yangtze has a /river#endingLocation of East China Searesourcepropertyval

33、ue.61The RDF Format = triples!The fundamental design pattern of RDF is to structure your XML data as resource/property/value triples!The value of a property can be a literal (e.g., length has a value of 6300 kilometers).Also, the value of a property can be a resource, as shown above (e.g., property-

34、Ahas a value of Resource-B, property-B has a value of Resource-C). We will see examplesof properties having a resource value in a little bit. Value-C value of property-Avalue of property-BNotice that the RDF design pattern is analternating sequence of resource-property.This pattern is known as strip

35、ing.62命名规范类名的第一个字母大写，属性名的第一个字母小写。便于快速识别类名，属性名。 6300 kilometers western Chinas Qinghai-Tibet Plateau East China Seauppercaselowercase.63RDF Model (graph)Legend: Ellipse indicates Resource Rectangle indicates literal string value.64rdf:Description + rdf:typeThere is still another way of representing t

36、he XML. This way makes it very clear that you are describing something, and it makes it very clear what the type (class) is of the thing you are describing: 6300 kilometers western Chinas Qinghai-Tibet Plateau East China SeaThis is read as: This is a Description about the resource /geograph

37、y/rivers#Yangtze.This resource is an instance of the River type (class). The /geography/rivers#Yangtzeresource has a length of 6300 kilometers, a startingLocation of western Chinas Qinghai-Tibet Plateau,and an endingLocation of the East China Sea.Note: this form of describing a resource is

38、called the long form. The form we have seen previously is anabbreviation of this long form. An RDF Parser interprets the abbreviated form as if it were this long form.65AlternativeAlternatively we can use rdf:ID rather than rdf:about, as shown here: 6300 kilometers western Chinas Qinghai-Tibet Plate

39、au East China Sea.66Equivalent Representations! 6300 kilometers western Chinas Qinghai-Tibet Plateau East China Sea 6300 kilometers western Chinas Qinghai-Tibet Plateau East China Sea 6300 kilometers western Chinas Qinghai-Tibet Plateau East China SeaNote: In the RDF literature the examplesare typic

40、ally shown in this form.67RDF N/1999/02/22-rdf-syntax-ns#IDabouttyperesourceDescription.68术语As you read the RDF literature you may see the following terminology:Subject: this term refers to the item that is playing the role of the resource.predicate: this term refers to the item that i

41、s playing the role of the property. Object: this term refers to the item that is playing the role of the value.SubjectObjectpredicateResourceValuepropertyEquivalent!.69RDF ParserThere is a nice RDF parser at the W3 Web site:/RDF/Validator/This RDF parser will tell you if your XMLis in the prop

42、er RDF format.70Example #2 6300 kilometers western Chinas Qinghai-Tibet Plateau East China Sea The Three Gorges Dam 1.5 miles 610 feet $30 billion Yangtze2.xmlModify the following XML document so that it is RDF-compliant:.71Note the two types (classes)RiverDamInstance: YangtzeProperties:lengthstarti

43、ngLocationendingLocationInstance: ThreeGorgesProperties:namewidthheightcost.72Dam - out of place 6300 kilometers western Chinas Qinghai-Tibet Plateau East China Sea The Three Gorges Dam 1.5 miles 610 feet $30 billion DamTypes (classes) contain properties . Here we see the River type containing the p

44、roperties - length, startingLocation, and endingLocation. It also shows River containing a type - Dam. Thus, there is a Resource that contains another Resource. This is inconsistent with RDF design pattern. (We are seeing one of the benefits of using the RDF format - to identify inconsistencies in a

45、n XML design.).73Property value must be a Literal or a Resource6300 kilometerspropertyValue is a Literal The Three Gorges Dam 1.5 miles 610 feet $30 billion propertyValue is a Resource.74Modified XML (to make it consistent) 6300 kilometers western Chinas Qinghai-Tibet Plateau East China Sea The Thre

46、e Gorges Dam 1.5 miles 610 feet $30 billion Yangtze2,v2.xmlThe Yangtze River has an obstacle that is the ThreeGorges Dam. The Damhas a name - The Three Gorges Dam. It has a width of 1.5 miles, a height of 610 feet,and a cost of $30 billion.75RDF Format 6300 kilometers western Chinas Qinghai-Tibet Pl

47、ateau East China Sea The Three Gorges Dam 1.5 miles 610 feet $30 billion Changed id to rdf:IDAdded the # symbolAs always, the other representations using rdf:about and rdf:Description are available.76RDF Model (graph).77 The Three Gorges Dam 1.5 miles 610 feet $30 billion 6300 kilometers western Chi

48、nas Qinghai-Tibet Plateau East China Sea Three-Gorges-Dam.rdfAlternatively, suppose that someone has already created a document containing information about the Three Gorges Dam:Yangtze.rdfThen we can simply reference the Three Gorges Dam resource using rdf:resource, as shown here:.78Note: reference

49、 is to a resource, not to a fileWhy was this the reference:and not this:That is, why wasnt the reference to a file?Answer:1. What if the file moved? Then the reference would break.2. By using an identifier of the Three Gorges Dam, and keeping a particular file unspecified, then an aggregator tool wi

50、ll be able to collect information from all the files that talk about the Three Gorges Dam resource (see next slide).Do Lab2.79Anyone, Anywhere, Anytime Can Talk About a ResourceIn all of our examples we have provided a unique identifier to resources, e.g.,/geography/rivers#YangtzeConsequent

51、ly, if another RDF document identifies the same resource then the data that it specifies gives additional data about that resource.An aggregator tool will be able to collect all data about a resource and present a consolidated set of data for the resource. Thats powerful!.80rdf:ID versus rdf:aboutWh

52、en should rdf:ID be used? When should rdf:about be used?When you want to introduce a resource, and provide an initial set of information about a resource use rdf:IDWhen you want to extend the information about a resource use rdf:aboutThe RDF philosophy is akin to the Web philosophy. That is, anyone,

53、 anywhere, anytime can provide information about a resource.81 6300 kilometers western Chinas Qinghai-Tibet Plateau East China S/geography/rivers/yangtze.rdf Dri Chu - Female Yak River Tongtian He, Travelling-Through-the-Heavens River Jinsha Jiang, River of Golden Sand /yangtze-alternate-names.rdf 6300 kilometers western Chinas Qinghai-Tibet Plateau East China Sea Dri Chu - Female Yak River Tongtian He, Travell