首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献,搜索用时 312 毫秒
1.
A user-based document management system has been developed for small communities on the Web. The system is based on the free annotation of documents by users. A number of annotation support tools are used to suggest possible annotations, including suggesting terms from external ontologies. This paper outlines some evaluation data on how users actually interact with the system in annotating their document especially on the use of standard ontologies. Results indicate that although an established external taxonomy can be useful in proposing annotation terms, users appear to be very selective in their use of the terms proposed and to have little interest in adhering to the particular hierarchical structure provided.  相似文献   

2.
Making annotations on books and learning materials is part of students' everyday life. Although there are many computer-based annotation systems, many people prefer to print digital documents and make annotations on physical paper. We introduce a classification scheme for computer-based annotation systems and provide an overview of different systems using this scheme. During our investigations, we identified several shortcomings in existing annotation systems: limitation to single document formats, no capturing of relations to reflect lateral reading, loss of context information an annotation was created in and limited sharing capabilities among collaborative users. To overcome these shortcomings, we introduce the concepts of Anchor Points , Artefacts and Spaces . Anchor Points define locations in arbitrary documents. Artefacts capture annotations on multiple Anchor Points in several documents, allowing students to map their current working context that typically contains several open documents and a relationship between them. Spaces are repositories for the learning materials and annotations that are automatically replicated among collaborative mobile users.  相似文献   

3.
Providing efficient access to XML documents becomes crucial in XML database systems. More and more concurrency control protocols for XML database systems were proposed in the past few years. Being an important language for addressing data in XML documents, XPath expressions are the basis of several query languages, such as XQurey and XSLT. In this paper, we propose a lock-based concurrency control protocol, called XLP, for transactions accessing XML data by the XPath model. XLP is based on the XPath model and has the features of rich lock modes, low lock conflict and lock conversion. XLP is also proved to ensure conflict serializability. In sum, there are three major contributions in this paper. The proposed XLP supports most XPath axes, rather than simple path expressions only. Conflict conditions and rules in the XPath model are analyzed and derived. Moreover, a lightweighted lock mode, P-lock, is invented and integrated into XLP for better concurrency.  相似文献   

4.
Internet上的化学数据库是宝贵的化学信息资源,如何有效地利用这些数据是化学深层网所要解决的问题。本文总结了化学深层网的特点,基于XML技术实现从数据库检索返回的半结构化HTML页面中提取数据的目标,使之成为可供程序直接调用做进一步计算的数据。在数据提取过程中,先采用JTidy规范化HTML,得到格式上完整、内容无误的XHTML文档,利用包含着XPath路径语言的XSLT数据转换模板实现数据转换和提取。其中XPath表达式的优劣决定了XSLT数据转换模板能否长久有效地提取化学数据,文中着重介绍了如何编辑健壮的XPath表达式,强调了XPath表达式应利用内容和属性特征实现对源树中数据的定位,并尽可能地降低表达式之间的耦合度,前瞻性地预测化学站点可能出现的变化并在XSLT数据转换模板中采取相应的措施以提高表达式的长期有效性。为创建化学深层网数据提取的XSLT数据提取模板提供方法指导。  相似文献   

5.
Jourdan  M.  Roisin  C.  Tardif  L. 《Multimedia Tools and Applications》2000,12(2-3):257-279
This paper introduces Kaomi, a scalable toolkit for designing authoring environments of multimedia documents. The underlying concept is to provide the designer of multimedia applications with a fast method to get an authoring system based on a set of synchronized views (the presentation view for displaying the document, the scenario view for showing the temporal organization of the document, ...) so that each view is the support of editing actions. Kaomi is flexible enough to support a variety of multimedia documents declarative formats. It is indeed a scalable toolkit since it provides facilities for extending and/or for modifying the resulting authoring environment. In addition, cross-platform portability is provided which allows operation in the heterogenous Internet environment. The use of Kaomi is mainly described through the design of two authoring environments: one for authoring a sub-set of the Smil standard of the W3C and the other one for Madeus, a constraint based multimedia language.  相似文献   

6.
Automatic ontology-based knowledge extraction from Web documents   总被引:4,自引:0,他引:4  
To bring the Semantic Web to life and provide advanced knowledge services, we need efficient ways to access and extract knowledge from Web documents. Although Web page annotations could facilitate such knowledge gathering, annotations are rare and will probably never be rich or detailed enough to cover all the knowledge these documents contain. Manual annotation is impractical and unscalable, and automatic annotation tools remain largely undeveloped. Specialized knowledge services therefore require tools that can search and extract specific knowledge directly from unstructured text on the Web, guided by an ontology that details what type of knowledge to harvest. An ontology uses concepts and relations to classify domain knowledge. Other researchers have used ontologies to support knowledge extraction, but few have explored their full potential in this domain. The paper considers the Artequakt project which links a knowledge extraction tool with an ontology to achieve continuous knowledge support and guide information extraction. The extraction tool searches online documents and extracts knowledge that matches the given classification structure. It provides this knowledge in a machine-readable format that will be automatically maintained in a knowledge base (KB). Knowledge extraction is further enhanced using a lexicon-based term expansion mechanism that provides extended ontology terminology.  相似文献   

7.
Collaborative social annotation systems allow users to record and share their original keywords or tag attachments to Web resources such as Web pages, photos, or videos. These annotations are a method for organizing and labeling information. They have the potential to help users navigate the Web and locate the needed resources. However, since annotations are posted by users under no central control, there exist problems such as spam and synonymous annotations. To efficiently use annotation information to facilitate knowledge discovery from the Web, it is advantageous if we organize social annotations from semantic perspective and embed them into algorithms for knowledge discovery. This inspires the Web page recommendation with annotations, in which users and Web pages are clustered so that semantically similar items can be related. In this paper we propose four graphic models which cluster users, Web pages and annotations and recommend Web pages for given users by assigning items to the right cluster first. The algorithms are then compared to the classical collaborative filtering recommendation method on a real-world data set. Our result indicates that the graphic models provide better recommendation performance and are robust to fit for the real applications.  相似文献   

8.
A limitation of current Web-based collaborative learning is the restricted ability of students to create and share individual annotations with annotated documents. Applying Web 2.0 collaborative annotation systems and analyzing students’ annotation behavior has attracted attention to improve collaborative learning. This study designed a personalized annotation management system 2.0 (PAMS 2.0) for managing, sharing, and reusing individual and collaborative annotations as well as providing a shared mechanism for discussion about shared annotations among multiple users.  相似文献   

9.
10.
Direct touch manipulation interactions with technology are now commonplace and significant interest is building around their use in the culture and heritage domain. Such interactions can give people the opportunity to explore materials and artefacts in ways that would otherwise be unavailable. These are often heavily annotated and can be linked to a large array of related digital content, thus enriching the experience for the user. Research has addressed issues of how to present digital documents and their related annotations but at present it is unclear what the optimal interaction approach to navigating these annotations in a touch display context might be.In this paper we investigate the role of two alternative approaches to support the navigation of annotations in digitised documents in the context of a touch interface. Through a control study we demonstrate that, whilst the navigation paradigm displays a significant interaction with the type of annotations task performed, there is no discernible advantage of using a natural visual metaphor for annotation in this context. This suggests that design of digital document annotation navigation tools should account for the context and navigation tasks being considered.  相似文献   

11.
Specifying and enforcing access control policies for XML document sources   总被引:10,自引:0,他引:10  
The Web is becoming the main information dissemination means in private and public organizations. As a consequence, several applications at both internet and intranet level need mechanisms to support a selective access to data available over the Web. In this context, developing an access control model, and related mechanisms, in terms of XML (eXtensible Markup Language) is an important step, because XML is increasingly used as the language for representing information exchanged over the Web. In this paper, we propose access control policies and an associated model for XML documents, addressing peculiar protection requirements posed by XML. A first requirement is that varying protection granularity levels should be supported to guarantee a differentiated protection of document contents. A second requirement arises from the fact that XML documents do not always conform to a predefined document type. To cope with these requirements, the proposed model supports varying protection granularity levels, ranging from a set of documents, to a single document or specific document portion(s). Moreover, it allows the Security Administrator to choose different policies for documents not covered or only partially covered by the existing access control policies for document types. An access control mechanism for the enforcement of the proposed model is finally described. This revised version was published online in August 2006 with corrections to the Cover Date.  相似文献   

12.
The use of declarative languages in digital TV systems, as well as IPTV systems, facilitates the creation of interactive applications. However, when an application becomes more complex, with many user interactions, for example, the hypermedia document that describes that application becomes bigger, having many lines of XML code. Thus, specification reuse is crucial for an efficient application development process. This paper proposes the XTemplate 3.0 language, which allows the creation of NCL hypermedia composite templates. Templates define generic structures of nodes and links to be added to a document composition, providing spatio-temporal synchronization semantics to it. The use of hypermedia composite templates aims at facilitating the authoring work, allowing the reuse of hypermedia document common specifications. Using composite templates, hypermedia documents become simpler and easier to be created. The 3.0 version of XTemplate adds new facilities to the XTemplate language, such as the possibility of specifying presentation information, the attribution of values to variables and connector parameters during template processing time and the template ability to extend other templates. As an application of XTemplate, this work extends the NCL 3.0 declarative language with XTemplate, adding semantics to NCL contexts and providing document structure reuse. In addition, this paper also presents two authoring tools: the template processor and the wizard to create NCL documents using templates. The wizard tool allows the author to choose a template included in a template base and create an NCL document using that template. The template processor transforms an NCL document using templates into a standard NCL 3.0 document according to digital TV and IPTV standards.  相似文献   

13.
14.
15.
语义标注是实现语义网的一个重要研究内容,目前已有很多标注方法取得了不错的效果。但这些方法几乎都没有注意到本体所描述的知识往往稀疏地分布在文档中,也未能有效地利用文档的组织结构信息,使得这些方法对质量较差的文档的标注不理想。为此提出了一种基于稀疏编码的本体语义自动标注方法((Semantic Annotation Method based on Sparse Coding, SAMSC),该方法先按本体知识描述从文档中识别出一定的语义作为初始值,再通过迭代解析文档段落结构和描述主题,完成本体知识与文档资源的相关系数矩阵计算,最后在全局文档空间中通过最小化损失函数来实现用本体对文档的语义标注。实验表明,该方法能有效地对互联网中大量良芬不齐的文档进行自动语义标注,对质量差的文档资源能取得让人接受的结果。  相似文献   

16.
The XML linking language (XLink) is a language for describing links between resources by means of XML attributes and a special namespace. The specification of the XLink language developed by the World Wide Web consortium provides only data structures for describing links and a minimal model of their behavior. In this paper, a language that allows the application to transparently formulate queries to XLink links and traverse the arcs determined by these links is suggested. The suggested language was named XPathLink, since it was developed as a natural extension of XPath, the language for addressing structural parts of XML documents. The XPathLink encapsulates complexities of XLink syntax from the application and provides a higher abstraction level when processing a set of XML documents connected by XLink links compared to the existing approaches. An implementation of the suggested XPathLink language by functional methods is considered. The functionality of the query language to XML documents connected by XLink links is achieved owing to the integration of the suggested implementation with the general-purpose programming language Scheme at the level of nodes of the processed XML documents and Scheme functions.__________Translated from Programmirovanie, Vol. 31, No. 3, 2005.Original Russian Text Copyright © 2005 by Lizorkin.  相似文献   

17.
Semantic search has been one of the motivations of the semantic Web since it was envisioned. We propose a model for the exploitation of ontology-based knowledge bases to improve search over large document repositories. In our view of information retrieval on the semantic Web, a search engine returns documents rather than, or in addition to, exact values in response to user queries. For this purpose, our approach includes an ontology-based scheme for the semiautomatic annotation of documents and a retrieval system. The retrieval model is based on an adaptation of the classic vector-space model, including an annotation weighting algorithm, and a ranking algorithm. Semantic search is combined with conventional keyword-based retrieval to achieve tolerance to knowledge base incompleteness. Experiments are shown where our approach is tested on corpora of significant scale, showing clear improvements with respect to keyword-based search  相似文献   

18.
SMIL is an XML-based language for specifying documents with temporal and spatial synchronization relationships, recommended by the W3C. However, SMIL has some limitations as a hypermedia authoring language. In order to overcome these limitations, this work presents the integration of SMIL documents with HyperProp, a hypermedia system based on an object-oriented model called NCM (Nested Context Model). As benefits, the integration makes both NCM facilities and HyperProp authoring and formatting tools available for SMIL documents. Furthermore, this work presents how the SMIL language can be extended to incorporate NCM facilities through the inclusion of new XML elements and attributes found in NCL, the NCM declarative language. Among the facilities, we can highlight the possibility of reusing document components and their presentation characteristics, offering flexibility in temporal specifications, adapting a document presentation according to user navigation and specifying n-ary relationships expressing causality or constraint among components.  相似文献   

19.
方勃  贺贵明 《计算机工程》2006,32(22):212-214
研发了一个基于IE核的协同浏览系统,应用Java Script语言编程实现界面动态画线,底层采用XML文档存储线条数据,可以实现对网页进行注释。此项研究的基本目标是把底层文档元素(如文本、图片等)和线条进行相互联系,实现线条的准确定位并为今后更多的应用打下基础。  相似文献   

20.
Hypermedia composite templates define generic structures of nodes and links to be added to a document composition, providing spatio-temporal synchronization semantics. This paper presents EDITEC, a graphical editor for hypermedia composite templates. EDITEC templates are based on the XTemplate 3.0 language. The editor was designed for offering a user-friendly visual approach. It presents a new method that provides several options for representing iteration structures graphically, in order to specify a certain behavior to be applied to a set of generic document components. The editor provides a multi-view environment, giving the user a complete control of the composite template during the authoring process. Composite templates can be used in NCL documents for embedding spatio-temporal semantics into NCL contexts. NCL is the standard declarative language used for the production of interactive applications in the Brazilian digital TV system and ITU H.761 IPTV services. Hypermedia composite templates could also be used in other hypermedia authoring languages offering new types of compositions with predefined semantics.  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号