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Semantic community Web portals
Abstract
Community Web portals serve as portals for the information needs of particular communities on the Web. We here discuss how a comprehensive and flexible strategy for building and maintaining a high-value community Web portal has been conceived and implemented. The strategy includes collaborative information provisioning by the community members. It is based on an ontology as a semantic backbone for accessing information on the portal, for contributing information, as well as for developing and maintaining the portal. We have also implemented a set of ontology-based tools that have facilitated the construction of our show case — the community Web portal of the knowledge acquisition community.
... Semantic Web content is published for machines via LD services and for human consumption using web-based LD applications, such as semantic portals. In general, semantic portals are information systems which aggregate information from multiple sources and publish them using Semantic Web technologies into user interfaces for solving information needs of end-users [10,20,[25][26][27]. Such portals, based on knowledge graphs published in LD services, typically provide the end-user with intelligent services for data exploration [14] and analysis based on the well-defined semantics of the content. ...
... The state of the application (e.g., the user's facet selections and the search results) is maintained using the strict unidirectional data flow enforced by Redux. 25 To reduce the complexity of handling side effects, asynchronous data fetching is carried out uniformly by a Redux middle- 26 Redux Observable provides a base for SAMPO-UI's epics, 27 which listen for asynchronous Redux actions, send API requests to the Node.js backend and other external services, implement debouncing when necessary, and handle the possible errors in the API responses. ...
This paper presents a new software framework, Sampo-UI, for developing user interfaces for semantic portals. The goal is to provide the end-user with multiple application perspectives to Linked Data knowledge graphs, and a two-step usage cycle based on faceted search combined with ready-to-use tooling for data analysis. For the software developer, the Sampo-UI framework makes it possible to create highly customizable, user-friendly, and responsive user interfaces using current state-of-the-art JavaScript libraries and data from SPARQL endpoints, while saving substantial coding effort. Sampo-UI is published on GitHub under the open MIT License and has been utilized in several internal and external projects. The framework has been used thus far in creating six published and five forth-coming portals, mostly related to the Cultural Heritage domain, that have had tens of thousands of end-users on the Web.
... The emergence of the web has brought about the development of new information retrieval techniquessuch as peer-to-peer information retrieval, multimedia information retrieval, semantic web retrieval system [17][18], and web information retrieval techniques [16,[19][20] in which hyper-link analysis and the use of anchor text are the most obvious, but spam detection, page quality assessment, URL analysis, and a multitude of other features have become important [21][22]. The problem with web information retrieval system is with the dynamism of the web, its rate of growth and change, and the increasing richness and complexity of the information sources available in it [18,23]. ...
... Web portals stand as a gateway [25][26] for easy access to the depository and provision of other web resources for web users. Web portals help organizations, professionals and communities easily disseminate information, effectively share knowledge, and creatively engage in collaborative endeavours [20,27]. Web portal is defined as a web site for specific audience that aggregates an array of content and provides a variety of services like search engines, directories, news, e-mail and chat rooms [25][26]. ...
SMS language is characterized by fashion and user’s creativity but needs a transformation to proper English words or spelling to formulate natural language and text processing activities. The proposed application, Web Information Retrieval System Architecture Based on SMS (WIRSABoSMS), normalizes SMS language to retain its original syntactic structure. The concept of mobile agents in web technology was introduced as a medium to achieving Short Message Service (SMS) normalization. SMS normalization was carried out with the adoption of multi-agent technology, as agents are involved in character search, sort, and compare of the strings written in SMS form into its parental orthography. This architecture was designed based on web information retrieval system (IRS) in order to achieve SMS normalization. BLEU (bilingual evaluation understudy) was used to evaluate the quality of text. BLEU scores compare the human judgment with that of the machine translation using two set of corpora. The outcome of syntactic text message normalization recorded an average of 90% performance (for the corpus collected from researchers) when compared with the similar test conducted with human judgment using BLEU scores metric in an health-related domain.
... For the purposes of this chapter, we define web portals as web sites that focus, to an extended degree, on a blend of the following features (Waloszek, 2001;Warner, 1999;Staab et al., 2000;Winkler, 2001;Hazra, 2002): their content (in terms of contained information or access to external information resources), their design (in terms of providing users with a pleasant, usable and stable environment), their personalization capabilities (in terms of serving users' specific preferences and needs), and their support to the formulation of virtual communities of users (in terms of bringing together users with similar interests and needs). The collection of more than one of the above features can be accepted as what is mainly differentiating web portals from simple web sites, and what drives the need for examining portal features as a superset of features that web sites usually have. ...
... Community support facilities are another essential feature of today's web portals. We can identify two main dimensions in user satisfaction from the community support services of a web portal (Staab et al., 2000;Lacher et al., 2001): ...
In this chapter, the issue of subjective evaluation of web portals for assessing user satisfaction is addressed. We present an evaluation framework for addressing the multiple dimensions of web portals that can affect users' satisfaction. The objective of this framework is to specify a set of total satisfaction indicators that allow monitoring the user-perceived quality level of a web portal and comparing the results from different evaluation groups. Initially, we study the multiple dimensions related with four main satisfaction factors: web portal content, web portal design, web portal personalization, and web portal community support. Then, we propose a multiple criteria model that synthesizes assessment upon the multiple satisfaction dimensions into a set of monitorable quality metrics. We present how the multi-criteria model is engaged throughout the framework stages to support subjective evaluation of web portals. Finally, we demonstrate the application of the proposed framework in the context of the summative evaluation of the Greek Go-Digital e-business awareness and training portal for very small and medium enterprises (vSMEs).
... These were typically either local communities (e.g., within a University campus) or interest-driven ones (e.g., professional associations). Early work in this field focused on community networks [95] and virtual communities [90], which then evolved into Web community portals [100] and finally into Web-based communities [10]. What makes this type of community particularly interesting is the fact that users start producing content for the community. ...
This book redefines community discovery in the new world of Online Social Networks and Web 2.0 applications, through real-world problems and applications in the context of the Web, pointing out the current and future challenges of the field.
Particular emphasis is placed on the issues of community representation, efficiency and scalability, detection of communities in hypergraphs, such as multi-mode and multi-relational networks, characterization of social media communities and online privacy aspects of online communities.
User Community Discovery is for computer scientists, data scientists, social scientists and complex systems researchers, as well as students within these disciplines, while the connections to real-world problem settings and applications makes the book appealing for engineers and practitioners in the industry, in particular those interested in the highly attractive fields of data science and big data analytics.
... This makes in the semantic Web, there is a lot of structured, machine understandable object information, and it provides the foundation for semantic search. Search object [28] of this method is mainly composed of domain ontology knowledge base, through the technology of semantic web, automatic reasoning of knowledge mining and knowledge discovery model of semantic search. Ideal semantic search system workflow is roughly as follows: firstly, the user's questions process by the user interface module. ...
... These were typically either local communities (e.g., within a University campus) or interest-driven ones (e.g., professional associations). Early work in this field focused on community networks [95] and virtual communities [90], which then evolved into Web community portals [100] and finally into Web-based communities [10]. What makes this type of community particularly interesting is the fact that users start producing content for the community. ...
This chapter serves as an introduction to the book on User Community Discovery, setting the scene for the presentation in the rest of the book of various methods for the discovery of user communities in the social Web. In this context, the current chapter introduces the various types of user community, as they appeared in the early days of the Web, and how they converged to the common concept of active user community in the social Web. In this manner, the chapter aims to clarify the use of terminology in the various research areas that study user communities. Additionally, the main approaches to discovering user communities are briefly introduced and a number of new challenges for community discovery in the social Web are highlighted. In particular we emphasize the complexity of the networks that are constructed among users and other entities in the social Web. Social networks are typically multi-modal, i.e. containing different types of entity, multi-relational, i.e. comprising different relation types, and dynamic, i.e. changing over time. The complexity of the networks calls for new versatile and efficient methods for community discovery. Details about such methods are provided in the rest of the book.
... Portal types include service portals collecting a large set of services together (e.g., Yahoo! and other "start pages"), community portals [138] acting as virtual meeting places of communities, and information portals [120] acting as hubs of data. Early discussions of semantic information portals include [94,120]. ...
Cultural Heritage (CH) data is syntactically and semantically heterogeneous, multilingual, semantically rich, and highly interlinked. It is produced in a distributed, open fashion by museums, libraries, archives, and media organizations, as well as individual persons. Managing publication of such richness and variety of content on the Web, and at the same time supporting distributed, interoperable content creation processes, poses challenges where traditional publication approaches need to be re-thought. Application of the principles and technologies of Linked Data and the Semantic Web is a new, promising approach to address these problems. This development is leading to the creation of large national and international CH portals, such as Europeana, to large open data repositories, such as the Linked Open Data Cloud, and massive publications of linked library data in the U.S., Europe, and Asia. Cultural Heritage has become one of the most successful application domains of Linked Data and Semantic...
... Owning the important characteristics discussed above, ontologies can serve as explicit conceptual knowledge models and provide the semantic vocabularies that make domain knowledge available to be exchanged and interpreted among information systems. Hence, they open new opportunities for developing a new line of semantic applications such as semantic search [35,61], semantic portal [89,60,55], semantic information integration [16,73,5], intelligent advisory systems [77,6], semantic middleware [54], semantic software engineering [18]. As we discussed above, the strength of an ontology is to support sharing knowledge between information systems. ...
In recent years, ontologies have attracted a lot of attention in the Computer Science community, especially in the Semantic Web field. They serve as explicit conceptual knowledge models and provide the semantic vocabularies that make domain knowledge available for exchange and interpretation among information systems. However, due to the decentralized nature of the semantic web, ontologies are highly heterogeneous. This heterogeneity mainly causes the problem of variation in meaning or ambiguity in entity interpretation and, consequently, it prevents domain knowledge from sharing. Therefore, ontology matching, which discovers correspondences between semantically related entities of ontologies, becomes a crucial task in semantic web applications. Several challenges to the field of ontology matching have been outlined in recent research. Among them, selection of the appropriate similarity measures as well as configuration tuning of their combination are known as fundamental issues that the community should deal with. In addition, verifying the semantic coherent of the discovered alignment is also known as a crucial task. Furthermore, the difficulty of the problem grows with the size of the ontologies. To deal with these challenges, in this thesis, we propose a novel matching approach which combines different techniques coming from the fields of machine learning, graph matching and information retrieval in order to enhance the ontology matching quality. Indeed, we make use of information retrieval techniques to design new effective similarity measures for comparing labels and context profiles of entities at element level. We also apply a graph matching method named similarity propagation at structure level that effectively discovers mappings by exploring structural information of entities in the input ontologies. In terms of combination similarity measures at element level, we transform the ontology matching task into a classification task in machine learning. Besides, we propose a dynamic weighted sum method to automatically combine the matching results obtained from the element and structure level matchers. In order to remove inconsistent mappings, we design a new fast semantic filtering method. Finally, to deal with large scale ontology matching task, we propose two candidate selection methods to reduce computational space. All these contributions have been implemented in a prototype named YAM++. To evaluate our approach, we adopt various tracks namely Benchmark, Conference, Multifarm, Anatomy, Library and Large Biomedical Ontologies from the OAEI campaign. The experimental results show that the proposed matching methods work effectively. Moreover, in comparison to other participants in OAEI campaigns, YAM++ showed to be highly competitive and gained a high ranking position.
... They serve as explicit conceptual knowledge models and provide the semantic vocabularies that make domain knowledge available to be exchanged and interpreted among information systems. Hence, they open new opportunities for developing a new line of semantic applications such as semantic search [21,36], semantic portal [52,35,31], semantic information integration [7,45,3], intelligent advisory systems [47,4], semantic middleware [30], semantic software engineering [9], etc. ...
Ontology matching is a key solution to the semantic heterogeneity problem. It discovers semantic correspondences between related entities of different ontologies to enable interoperability. The fundamental challenging issues, that all automated ontology matching systems have to deal with, are matcher selection, combination and tuning [18, 46]. In this paper, we describe our approach named YAM++ by solving these issues in each of YAM++'s component, i.e., element matcher, structure matcher, combination and selection. In particular, in the element matcher, we propose a machine learning based method to automatically combine different terminological similarity metrics. In the structure matcher, we propose a similarity propagation method to deal with structural heterogeneity of ontologies. In the combination and selection component, we propose a dynamic weighted sum method to automatically combine the matching results of element and structure matchers. Moreover, this method also automatically ascertains the filter's threshold for each matching scenario. The experimental results show that our proposed methods outperform other existing methods. Additionally, in both Benchmark and Conference track in OAEI 2011 campaign, YAM++ achieved high ranked positions in comparison with other participants.
... Thus, based on web-based technology, knowledge portal is required and developed to facilitate users finding relevant, domain-specific information by using university database. The portal should provide access to information related to a wide variety of activities [12]. In the first place it will probably concentrate on teaching and learning and student administration, other areas will also needed to be considered: student's life service, financial assistant, passport and visa service, etc. ...
Knowledge portal is an approach used to provide view of domain-specific information on the World Wide Web [13]. In this paper, we present one approach by using ontology engineering as a conceptual backbone and relationships for knowledge extracting, structuring and formalizing as a comprehensive way for building knowledge portal. For illustration of a practical ontology development of knowledge portal, the described ideas are implemented in a system design for international student service.
... professional associations). Early work in this field focused on community networks (Schuler 1994) and virtual communities (Rheingold 1993 ), which then evolved into Web community portals (Staab et al. 2000) and finally into Web-based communities (Bouras et al. 2005). In the context ofFig. ...
One of the major innovations in personalization in the last 20 years was the injection of social knowledge into the model of the user. The user is not considered an isolated individual any more, but a member of one or more communities. User communities have been facilitated by the striking advancements of electronic communications and in particular the penetration of the Web into people’s everyday routine. Communities arise in a number of different ways. Social networking tools typically allow users to proactively connect to each other. Alternatively, data mining tools discover communities of connected Web sites or communities of Web users. In this article, we focus on the latter type of community, which is commonly mined from logs of users’ activity on the Web. We recall how this process has been used to model the users’ interests and personalize Web applications. Collaborative filtering and recommendation are the most widely used forms of community-driven personalization. However, we examine a range of other interesting alternatives that are worth investigating further. This effort leads us naturally to the recent developments on the Web and particularly the advent of the social Web. We explain how this development draws together the different viewpoints on Web communities and introduces new opportunities for community-based personalization. In particular, we propose the concept of active user community and show how this relates to recent efforts on mining social networks and social media.
... Existen dos elementos clave para lograr que un ordenador entienda el significado de un documento de la web. Por un lado, las ontologías (especificaciones formales y explícitas de una conceptualización compartida - Gruber, 1993;Borst, 1997;Studer, et al., 1998-), que establecen los términos relevantes del dominio (conceptos, atributos, relaciones, instancias, etc.); por otro lado, la anotación semántica de textos (Benjamins, et al., 1999;Motta, et al., 1999;Luke, et al., 2000;Staab, et al., 2000;Aguado, et al., 2002 (a;b;c);Benjamins, et al., 2003;Wilcock, et al., 2004), que hace explícito para un ordenador el significado de estos términos cuando aparecen en un texto, enlazán-dolos con sus asociados dentro de las ontologías consideradas en la anotación, mediante los mecanismos de referencia apropiados de cualquiera de los lenguajes propios de la web semántica: xml, rdfs, OWL, etc. (Gómez Pérez;Corcho, 2002;Dean;Schreiber, 2003;Peis, et al., 2003). ...
Resumen: Se presenta una aproximación práctica a la cons-trucción de ontologías a partir de tesauros inspirada en la meto-dología Methontology, que per-mite hacer uso de los lenguajes propios de la definición de onto-logías y anotación semántica ba-sada en las mismas. Asimismo es una alternativa a la publicación de tesauros en la web semán-tica mediante SKOS-Core, que es la propuesta del World Wide Web Consortium (W3C), y ofrece más semántica que el tesauro de partida y que su implementación mediante SKOS-Core. También se detalla una arquitectura ge-nérica para la representación de dominios con dos niveles de descripción: una ontología de representación del conocimiento, basada en las facetas de Ranga-nathan (1967), para representar las relaciones de alto nivel del dominio, más una ontología de dominio, que proporciona la des-cripción de un campo particular del dominio. Abstract: A practical approach to the development of ontologies from thesauri is presented, using the Methontology methodology, which permits the use of any language developed so far for the implementation of ontologies, as well as semantic web annotations based on these ontologies. This approach is an alternative to SKOS-Core, the World Wide Web Consortium (W3C) approach to publication of thesauri within the semantic web. The advantage of our approach is that it provides significantly more semantic information than a thesaurus (and, hence, than does SKOS-Core). A two-level ontological architecture for domain representation is also described, consisting of a knowledge representation ontology [based on Ranganathan's (1967) facets] for the representation of high-level relationships in the domain and a domain ontology for the description of a particular field within the domain.
... The spread of XML based applications will contribute a lot in this direction. We expect also many applications of network analysis in the implementations of the Semantic Web [9,23,29,31]. ...
In the paper different ways to derive networks from the textual data and an overview of (possible) applications of network analysis to the analysis of texts is presented. Several examples of analyses of different text networks are given as illustrations.
... • The Knowledge Annotation initiative of the Knowledge Acquisition community (KA2: http://ka2portal.aifb.uni-karlsruhe.de) which is an example of a semantic portal guided by ontologies (Staab et al., 2000). In this project, a community web portal was developed. ...
In recent years, the package tour industry has fostered a dependency on technology for its operational and strategic management. However, the existing tools for facilitating searches of availability of package tours do not provide intelligent matching between offered package tours and the personal requirements of the travellers. The objective of this research work was to design an intelligent web portal to serve as service provider in tasks related with package tours. This portal aims at helping people living in Europe to find package tours that match their personal travel preferences. For this purpose, the knowledge of the package tour domain has been represented by means of ontology. Additionally, the ontological component allows for defining an ontology‐guided search engine, which provides more intelligent matches between package tours offers and travelling preferences.
... As these technologies become more refined, the website's architecture will allow for additional relationships to be stated about the data allowing the machine to interpret and suggest more relevant results to the user [29,31]. As the websites focus, membership, and content evolve to meet the needs of the community, the ontology should also be updated to mirror the growing user base [11,32,33]. Researchers claim that the ontology can also allow for interoperability [20]. ...
People in crisis often have no idea where to find help in their commu- nity. The 9-1-1 emergency number can get "flooded" with non-emergency calls. The 2-1-1 system is a new service where anyone can get current information about local community services, via internet or telephone, re- gardless of their location. The 2-1-1 system can be used in times of need, or just for general information about services in the community. We propose a framework for information and referral systems that provides stability, integrates with other systems, and will sustain over time. We use a service oriented architecture and a relational database model, and include an on- tology system that utilizes the Extensible Markup Language (XML) and the Resource Description Framework (RDF) to deliver requested data to the user. A taxonomy system can be implemented that is consistent with other referral services. Our framework enables interoperability with other database systems, and is adaptable as needed.
... According to the World Wide Web consortium, it is "the universal format for structured documents and data on the Web" (W3C 2002a). XML is already widely used for data interchange, and efforts are being made to support XML data management (Shanmugasundaram, Tufte, Zhang, He, DeWitt & Naughton 1999, Goldman, McHugh & Widom 1999, Ceri et al. 2000, Lomet 2001) and query languages (W3C 2002c, Deutsch, Fernandez, Florescu, Levy, Maier & Suciu 1999, and to create ontologies for various domains (SemanticWeb 2002, W3C 1999b, LabBook 2002. ...
... Let us introduce two different approaches for using ontologies to guide the development of semantic web portals. On the one hand, the KA2 project (Staab et al., 2000) initiative is an example of a semantic portal guided by ontologies. In this work, a community web portal was developed. ...
Nowadays, employment has a huge social importance. Current tools for facilitating job searches lack in providing intelligent matching between employer advertisements and the curriculum vitae of the candidates. The objective of this research work was to develop an intelligent web portal to serve as service provider in recruitment tasks. This portal aims at helping people living in the region of the South-east of Spain to find a job. For this purpose, the knowledge of the recruitment domain has been represented by means of ontology, which has been used to guide the design of the application and to supply the system with semantic capabilities. Furthermore, the ontological component allows for defining an ontology-guided search engine which provides more intelligent matches between job offers and candidates' curricula. Finally, this work covers the design of the ontology and the development of the web portal. Both issues are discussed and some validation results are presented.
... The essential aspect that is focused on this study can be seen as the state of the evolution of web portals and survey existing portals that make use of Semantic Web technologies [9]. The scope of portals investigated is restricted to Semantic Web portals (SW portal for short), which are defined as follows: ...
Current state of the art of typical search engines like Google, Yahoo and others are delivering references in terms of web URL or links to the related website. As such the results did not deliver the right answers required to the users needs. In addition to that as soon as the users require a collection of the information obtained, these search engines failed to do so resulting in the human intervention in-combining the information from several sources. Due ot the advancement and the vast number of sites and information on the web, demands in providing higher precision results are required to aid users in obtaining the most relevant result to the search process. One of the promising areas of the Semantic Web is enhancing the query capabilities for information. Small vertical vocabularies and ontologies have emerged, and the community of people using these and generating data is growing daily. However queries or search mechanisms that utilizea the vasrt amount of vocabularies, ontologies and data in digital libraries is still very much lacking. Therefore searching over heteregoneous records, data in digital library community or the Web has become a well known problem to the mass public. As such a solution is needed for a federated search across multiple resources available. However it remains unclear on how Semantic Web or its technology is used in constructing a digital library system or aid in enhancing the quality of the search results performed. This leads to the current work proposed, as work will be conducted to provide possible components that will construct the semantic web portal. The work performed is essential to facilitate semantic searches for research community in large-scale distributed digital library system. The subject research community is chosen particularly to aid in ensuring hat result obtained are accordingly to the users relevant needs. The expected outcomes of the research are an architecture that utilizes the semantic technology that will promote semantic web portal in the digital library and a semantic search mechanism that will provide better results and a combination of useful results relevant to the users.
... Ontology's have shown their usefulness in application areas such as knowledge management, bioinformatics, elearning, intelligent information integration [19], information brokering [20] and natural-language processing [21]. Now it is the positional and challenging area for text classification. ...
Feature selection is of paramount concern in document classification process which improves the efficiency and accuracy of text classifier. Vector Space Model is used to represent the ¿Bag of Word¿ BOW of the documents with term weighting phenomena. Documents representing through this model has some limitations that is, ignoring term dependencies, structure and ordering of the terms in documents. To overcome this problem semantic base feature vector is proposed. That is used to extracts the concept of term, co-occurring and associated terms using ontology. The proposed method is applied on small documents dataset, which shows that this method outperforms then term frequency/ inverse document frequency (TF-IDF) with BOW feature selection method for text classification.
... In terms of managing information and information retrieval in a flexible and semantically sensitive way there are important recent developments in the area of the Semantic Web that are relevant here as well as results from past and current framework projects. Thus work has been done on automated information extraction and classification techniques using ontologies as a classification principle currently developed in association with the SHOE and Parka projects [1] [2] [3] and others in the ontology community [4] including KAON, to name but a few. The basis of the work on integrated information and knowledge management paradigms developed as part of the Burma-X and NOPIK FP5 projects is reported in [5]. ...
The paper presents results from NOPIK, a current IST project, which is in its final stages. A number of tools to support team-based problem solving activities have been developed and evaluated with the project users and with overall positive results. The toolset also sports a distributed architecture where separate installations and their content can be synchronised with a central server. This in principle provides an architecture enabling collaboration and sharing in a relatively static environment, but in an open world where ad hoc connectivity is required a peer to peer architecture is needed and which is proposed and discussed in this paper. Our research has shown that organisations are usually sensitive to letting documents be stored off their premises and thus solutions such as P2P offer the potential to overcome these barriers and provide an ad hoc connectivity otherwise not easily achievable.
... The model for personalisation used in the design of the Common Sense Design Agent draws on the work done for the The Personal Publication Reader [37] and CHIP [38] projects, countenancing several factors of personal preference among previous browsing context, query, check-box preference setting and property weighting. Significant numbers of research projects framing approaches to the personalisation of presentation and visualisation aspects of data retrieval have been undertaken over the last decade (see, for example, [39, 38] ). This research commonly relies on either of, or combinations of, context of behaviour analysis and inference or domain programming and user preference declaration. ...
This paper provides an outline for a general purpose Seman-tic Web browser which aims to provide a sensible visualisation for any RDF data. Sketched here is a web proxy for common browsers which in-terlopes on RDF/XML transmissions, transforming them at 'diplaytime' to provide the viewer with a meaningful view on the intercepted model. It suggests using the Wikipedia-style million minds approach to develop-ing two large repositories, one of common sense knowledge about design principles, and another of design templates using the Fresnel pattern. An 'intelligent' agent could make use of these two repositories, as well as personalisation information and RDF introspection, in the rendering of useful interpretations of raw RDF material.
... Os metadados podem ser utilizados como uma forma de representação do mundo real. São exemplos de linguagens de metadados, que podem ser utilizadas para marcar ou anotar estes recursos informacionais: o XML e o RDF [17]. ...
Resumo -Diante do aumento na utilização dos guidelines (diretrizes clínicas), um grande esforço faz-se necessário para sua elaboração com qualidade e a possibilidade de torná-las compartilháveis entre diferentes instituições e utilizáveis em diferentes aplicações computacionais. Este artigo apresenta um modelo e protótipo para gestão e modelagem de guidelines cujas contribuições serão avaliadas por agentes computacionais e distribuídas através do conceito da Web Semântica. Abstract -Ahead of the increase in the clinical guidelines' use, a great effort becomes necessary for its quality elaboration and the possibility to become them shareable between different institutions and usable in different computational applications. This article presents a model and prototype for guidelines' management and modeling whose contributions will be evaluated by computational agents and distributed through the Semantic Web concept.
... The use of semantically sophisticated tools for mining, filtering, and querying vast amounts of information on the Web has been studied in detail [Boley et al. 1999;Chakrabarti and Batterywala 2000;Cooley et al. 1997;Grosky et al. 2002;Lieberman 1999;Staab et al. 2000]. In particular, when people are confronted with large amounts of information on a topic they have significant interest in, their goal is to first grasp its overall makeup. ...
Information retrieval has traditionally been concerned with extracting isolated facts from large knowledge bases. There are times, however, when users have a different goal – they seek to understand the structure of the data as a whole, so that they have a conceptual framework into which individual facts can later be assimilated. Today's search tools do not explicitly support this. They typically provide only a query-response mechanism for obtaining isolated facts, one at a time. Users are forced to form a mental model on their own, inferring the broader structure from these disconnected details. Tools specifically designed to help users organize large information spaces are proposed. Such tools will raise the level of abstraction, so that the categories of mental perception can be stated, examined, and reasoned about in their own right. The user's subjectivity will be honored; different people often have different views of the same data, and they want to organize it according to their own individual perceptions. The need for such tools, and the properties designers should strive for, are discussed. A prototype that demonstrates the validity of this kind of tool is presented.
... etc. are usually convenient and efficient solutions for document sharing, however, problematic due to restrictions in data organization and semantic expressiveness. This led to the idea of semantic web portals combining semantic web technology with information portal technology (Staab et al., 2000). ...
In this paper, an attempt is made to conceptually unite three different application areas for semantic technologies, namely personal Knowledge Management, social networking, and Peer-to-Peer information-sharing. Until now, semantic technology has been applied to each of these application areas separately or in binary combinations only. By functionally combining all three areas in a single application, it is hoped to sketch a compelling Semantic Web system that will help increase the spread and acceptance of the Semantic Web vision. A concrete usage scenario of a community of researchers is used to demonstrate the approach.
... An extensive overview and state-of-art of existing Semantic Web portals is delivered by Lausen et al. [9]. An approach embedding all phases of a community Web portal (i.e., information accessing, information providing, portal development and maintenance) is described in a paper by Staab et al. [15]. Our work is focused on the existing classmates' portals. ...
Current distributed ontology practices are analyzed and illustrated with typical web portals supporting communication, data sharing and activities of former classmates. The inflexibility and restrictions imposed on users of such portals are demonstrated to support the thesis that introduction of community-driven ontology management is crucial for full-fledged satisfaction of the end user needs on the Web.
... OntoSeek combines an ontology-driven content-matching mechanism with a moderately expressive representation formalism. Benjamins et al. [1999] and Staab et al. [2000] propose an ontology-based system, the Ontobroker, to provide better and easier access to relevant information about knowledge acquisition from web pages. Craven et al. [2000] developed the WEB→KB system which automatically create a computer readable knowledge base whose content mirrors that of the World Wide Web. ...
This paper presents an adaptive agent-based framework for knowledge sharing. The framework supports semantic-based knowledge retrieval and filtering through the usage of ontologies, case-based reasoning, and genetic algorithms. First, the concept of ontologies is applied to build users' profiles and resolve semantic conflicts among multiple knowledge sources – User Profile Ontology (UPROL), Semantic Conflict Resolution Ontology (SCROL), and Domain ontology. UPROL is used by the profile agent to map users' interests into a common terminology. SCROL allows multiple views and interpretations of a given terminology by different users and applications. Domain ontology is also used to organize information sources and direct search processes. We also utilize collaborative filtering through case-based reasoning techniques for knowledge filtering and recommendation. Finally, by adopting the survival-of-the-fittest rule of genetic algorithms, we make the system continuously adapt to changing users' profiles. In conclusion, our adaptive agent-based approach allows knowledge seekers to access tacit yet interoperable knowledge.
... Community-driven ontology construction has been applied in a number of case studies in various domains, such as in environments to support work of an organization as well as for entertainment and keeping in touch [5,10,16] or infrastructures for Semantic Wikis [11,15]. The Semantic Web approach [2,6] and development of knowledge portals [8,13] brought numerous technologies for knowledge representation and sharing that serve as a ground for community-driven ontology evolution. Ontology evolution with social aspects [3] become generally important as there is an emerging need to understand how online communities advance their shared knowledge over time, how to measure and predict the ontology evolution rates, and how these rates co-relate with communities' successes or fruitful collaboration outcomes. ...
Communities on the Web capture, represent, and evolve their knowledge using ontologies, either explicitly or implicitly. The
Gene Ontology project is a typical and advanced case study of a community-driven ontology creation and evolution. We use this
case study to derive and illustrate factors that limit dynamic knowledge sharing in community environments. Specifically,
we analyze ontology evolution implemented by the Gene Ontology community over the period of five years, as well as the used
infrastructures for knowledge management. We observe limitations of communication practices within community-driven ontology
construction, the lack of correlation between requested and actual changes in the ontology, and propose social and technical
guidelines for making ontology-based knowledge sharing and evolution more responsive to users’ needs.
With the advent of the web technologies, portals are providing a wide range of comprehensive support for information processing and management focusing on content management with specific foundation for knowledge development. Knowledge management portals are emerging as web tools that can assist facilitate knowledge management in the aspect of learning, social awareness, policy implementation, and empowering the common citizen of the community. Knowledge management portals can be a rigid platform for providing integrated access to relevant content and resources in one location, for sharing and distributing information, and for bringing the community people together for knowledge interchange. This chapter focuses on the aspects of knowledge management portals through a horizontal literature review and put forwards a few cases that are being utilized in various aspects of the society for the knowledge attainment of the general public of the society.
Die Erforschung einer Domäne generiert differenzierte Forschungsergebnisse (Theorien, Methoden, Modelle, empirische Ergebnisse, Softwareprototypen etc.). Orientierungshilfe bei der Identifikation und Auswahl von in Wissenschaft und Praxis relevanten Forschungsergebnissen bieten interaktive Analysen auf Basis morphologischer Kästen und grafischer Wissenskarten. Die Kästen können die Suche auf einem Forschungsportal inhaltlich strukturieren, während grafische Wissenskarten die Vorzüge von Visualisierungen für die Gestaltung von Forschungsportalen als Instrumente nutzbar machen. In diesem Kapitel wird am Beispiel des betrieblichen Kompetenzmanagements im demografischen Wandel erörtert, wie sich ein morphologischer Kasten und grafische Wissenskarten für ein ausgewähltes Forschungsfeld entwickeln lassen. Dabei werden verschiedene Vorgehensweisen parallel verfolgt. Der Verbund stellt sicher, dass einerseits die das Portal später nutzende Community in die Entwicklung seiner Konzepte eingebunden wird und andererseits die Potenziale einer Auswertung von Massendaten teilautomatisiert und damit kostenreduziert genutzt werden.
At some point, the understudies have insufficient information to proceed further in their career, so getting right exhortation from experienced individual is vital which will be accomplished by establishing an online alumni interface. With this the alumni can communicate to the students regarding job opportunities and the students can share their department activities to the alumni. The proposed system has the dynamic architecture and less static content, which can empower the full duplex association between all graduated students and understudies. This paper portrays how the system will function and collaborate the graduated class with the present understudies.
In this article, we discuss the issues involved in adding a native score management system to object-relational databases, to be used in querying Web metadata (that describes the semantic content of Web resources). The Web metadata model is based on topics (representing entities), relationships among topics (called metalinks ), and importance scores (sideway values) of topics and metalinks. We extend database relations with scoring functions and importance scores. We add to SQL score-management clauses with well-defined semantics, and propose the sideway-value algebra (SVA), to evaluate the extended SQL queries. SQL extensions and the SVA algebra are illustrated through two Web resources, namely, the DBLP Bibliography and the SIGMOD Anthology.SQL extensions include clauses for propagating input tuple importance scores to output tuples during query processing, clauses that specify query stopping conditions, threshold predicates (a type of approximate similarity predicates for text comparisons), and user-defined-function-based predicates. The propagated importance scores are then used to rank and return a small number of output tuples. The query stopping conditions are propagated to SVA operators during query processing. We show that our SQL extensions are well-defined, meaning that, given a database and a query Q, under any query processing scheme, the output tuples of Q and their importance scores stay the same.To process the SQL extensions, we discuss two sideway value algebra operators, namely, sideway value algebra join and topic closure, give their implementation algorithms, and report their experimental evaluations.
This paper introduces inter-layer filters for the scalable extension of High Efficiency Video Coding (SHVC) standard, which is being developed by the Joint Collaborative Team on Video Coding (JCT-VC). The major new coding tool in SHVC is inter-layer texture prediction. It provides about 18% average BD-rate reduction compared with HEVC two-layer simulcast. In the case of spatial scalability, base layer reconstructed pictures are up-sampled to the enhancement layer resolution to generate inter-layer texture prediction. A set of 2D separable 8 taps (luma) and 4 taps (chroma) DCT based interpolation filters, which follow the design principles of HEVC motion compensation interpolation filter, are used in the up-sampling process. In the case of SNR scalability, the up-sampling process is not needed since the reference layer has the same spatial resolution as the current layer but encoded with lower quality. This paper proposes a novel inter-layer filter with denoising effect for SNR scalability to improve enhancement layer coding efficiency and equalize the number of stages in inter-layer processing between SNR and spatial scalabilities. Experimental results show that the usage of inter-layer de-noising filter in SNR scalability provides up to 7.5% BD-rate reduction and has observable improvement on subjective visual quality.
The Semantic Web is the next generation of current Web. It enables computers to cooperate with people well. Web Services become more prevalent now. It lifts the Web function from the collection of information to an upper level of processing information. In order to fulfill the evolution from the services of current Web into the Semantic Web to benefit the full potential of the Web, in this paper we present our preliminary ideas of building Semantic Web service system based on a multi-agent system. Our system consists of three main aspects: multi-agent system, Web service management and Semantic Web contents. In order to demonstrate the effectiveness of our mechanisms, we build a semantic community Web portal service system for Semantic Web community.
University campuses and municipalities are currently spending large sums of money to acquire systems that allow dissemination of information in emergency situations. The majority of these are mass notification systems that first register multiple contacts for community residents (email, phone, pager, etc.) and then deliver information to those residents at the push of a button to leave a message. Motivated by the limitations of such approaches, in this work we explore the use of existing metropolitan network infrastructures to design a new Location-Based Emergency Notification Service (LENS). LENS selectively redirecting residents to safety information using existing communication channels (e.g., Web browsing over HTTP). LENS eliminates the need for registration, provides minimal interruption to users and involves a low-cost setup. We prototype LENS using off-the-shelf components and demonstrate efficiency and scalability for a 60,000 user campus environment.
Semantic web portal is expected to overcome the shortcomings of the current web portals through advanced semantic web technologies and to be an effective and efficient method of knowledge sharing. In order to contribute to the knowledge sharing, semantic web portal needs to construct and integrate ontologies of each organization. Also, it needs to support search and navigation of inter-related knowledge. In this paper, we will design a semantic web portal that satisfies such requirements in the domain of display industry, and construct an ontology which links various knowledge of different fields. Moreover, we want to suggest an effective and automatic search/navigation method that supports customers who do not know the details of an ontology to easily get the desired results.
With more and more publisher bodies publish machine-processable content on the web, the so-called web-3.0 era emerges. These contents, normally in forms of RDF triples, make the Internet a huge knowledge base. Hence, the Internet now empowers virtual communities than ever before. This paper introduces a framework for web publishing community that focuses on a domain of interest. The system starts from a predefined domain ontology, and crawls resources from the web of data. By semantic match making, the system facilitates users finding related resources and sharing content. The knowledge base can evolve with users' participation. Thus the system improves communications between human users by improving interoperation among machines.
Internet of Things (IoT) as an important and ubiquitous service paradigm is one of the most important issues in IoT applications to provide terminal users with effective and efficient services based on service community. This paper presents a semantic-based similarity algorithm to build the IoT service community. Firstly, the algorithm reflects that the nodes of IoT contain a wealth of semantic information and makes them to build into the concept tree. Then tap the similarity of the semantic information based on the concept tree. Finally, we achieve the optimization of the service community through greedy algorithm and control the size of the service community by adjusting the threshold. Simulation results show the effectiveness and feasibility of this algorithm.
Hypertext is a discipline which deals with the composition and arrangement of documents. Common hypertext preoccupations are the ways in which web pages can be linked together and the types of navigation pathways that provide users with convenient access to relevant information. Until now, the linking task has been left to the intelligence of the document author or the web site designer because the rationale for linking is inevitably based upon human understanding of the document contents.
Previous attempts to automate the linking process have often yielded disappointing results. Now, the ability to model a domain of discourse with an ontology holds out the promise of computationally reasoned and reasonable linking services. This chapter describes some attempts to augment hypermedia systems with ontologies in order to provide, or improve, hypertext.
This paper shows how semantic web techniques can be applied to solving problems of distributed content creation, discovery, linking, aggregation, and reuse in health information portals, both from end-user's and content publish- ers's viewpoints. As a case study, the national semantic health portal HEALTH- FINLAND is presented. It provides citizens with intelligent searching and brows- ingservicestoreliableandup-to-datehealthinformationcreatedbyvarioushealth organizations in Finland. The system is based on a shared semantic metadata schema, ontologies, and mash-up ontology services. The content includes meta- data of thousands of web documents such as web pages, articles, reports, cam- paign information, news, services, and other information related to health.
This paper describes an implemented model of a portal framework through which users in an enterprise may control their activities by following structured plans. The artefacts they manipulate, and the temporal schedules associated with them, are regulated by finite-domain constraints to express and enforce enterprise requirements. A significant feature of the model is a well-defined formulation of experience extracted from the user interface in the form of reusable episodes. Such episodes provide a valuable resource for enterprise users engaged in the development of their plans.
Technology for knowledge management has so far focused on the management of knowledge containers. We present an approach that is oriented towards managing knowledge contents instead by identifying knowledge items at various levels of formality. This is done by providing various types of meta data that are tied to ontologies for conceptual interlinkage. Knowledge items are embedded into knowledge processes, which are supported by a suite of ontology-based tools. In order to handle this sort of rich knowledge process, we introduce a meta process that puts special emphasis on constructing and maintaining the ontology when introducing knowledge management systems. In order to elucidate our approach, we describe a case study about the building of CHAR, the Corporate History AnalyzeR.
Due to cross-border crimes rise, the EU is working on the development of international judicial cooperation between Member States. Increase of illegal immigration, trafficking of drugs, weapons and human beings, and the advent of terrorism, made necessary a stronger judicial collaboration between States. Particular attention is paid on judicial collaboration between Western Balkans and the EU. CARDS program is a suitable evidence of it. Judicial cooperation includes mutual recognition of judicial decisions, cooperation in investigations, approximation of penal legislation of involved states, including the penalties. During the investigations, prior to an international request for warrant of arrest, an exchange of information on criminal offences and administrative infringements takes place between magistrates belonging to different countries.; this create new need for judicial cooperation environment supporting a cross-border judicial cooperation between EU and Countries of enlarging Europe.
Topic Maps and RDF are two independently developed proposals for the representation, in-terchange, and exploitation of model-based data on the Web. Each proposal has established its own user communities. Each of the proposals allows data to be represented as a graph with nodes and labeled arcs which can be serialized in one or more XML-or SGML-based syntaxes. However, the two data models have signicant conceptual differences. A central goal of both proposals is to dene a format for the exchange of knowledge on the Web. In order to prevent a par tition of the Web into collections of incompatible resources, it is nec-essary to investigate ways to integrate Topic Maps and RDF data. This paper presents a rst step by representing Topic Maps as RDF data and thus allowing Topic Maps to be queried by an RDF-aware infrastructure. We achieve this by mapping a Topic Map graph model to the RDF graph model. All information from the Topic Map is preserved, such that the mapping is reversible. The mapping is per formed by modeling the graph features of a Topic Map graph model with an RDF graph. The result of the mapping is an RDF-based representation of Topic Maps data that can be queried as an RDF data source by an RDF-aware query processor. The Semantic Web is a vision: the idea of having data on the Web dened and linked in a way that it can be used by machines not just for display purposes, but for automation, integration and reuse of data across various applications.
One way overcome the weakness of semantic web to make it more user friendly is by displaying, browsing and semantically query data. In this research, we propose Semantic Web Research Community Portal at Faculty of Information Science and Technology – Universiti Kebangsaan Malaysia (FTSM RC) as the lightest platform of Semantic Web. This platform assists the users in managing the content and making visualization of relevant semantic data by applying meaningful periodically research. In such a way it will strengthen the research information related to research, publications, departments, organizations, events, and groups of researchers. Moreover, it will streamline the issuance process, making it easier for academic staff, support staff, and faculty itself to publish information of faculty and studies research information. By the end, this will provide end users with a better view of the structure of research at the university, allowing users to conduct cross-communication between faculty and study groups by using the search information.
Cultural heritage is a promising application domain for semantic web technologies due the semantic richness and heterogeneity
of cultural content, and the distributed ways in which the content is created in memory organizations and by citizens. This
chapter overviews issues and research related to creating semantic portals for publishing cultural heritage collections and
other content on the web.
One of the main shortcomings of Semantic Web technologies is that there are few user-friendly ways for displaying, browsing
and querying semantic data. In fact, the lack of effective interfaces for end users significantly hinders further adoption
of the Semantic Web. In this paper, we propose the Semantic Web Portal (SWP) as a light-weight platform that unifies off-the-shelf
Semantic Web tools helping domain users organize, browse and visualize relevant semantic data in a meaningful manner. The
proposed SWP has been demonstrated, tested and evaluated in several different use cases, such as a middle-sized research group
portal, a government dataset catalog portal, a patient health center portal and a Linked Open Data portal for bio-chemical
data. SWP can be easily deployed into any middle-sized domain and is also useful to display and visualize Linked Open Data
bubbles.
KeywordsSemantic Web data-browsing-visualization
The paper introduces a new approach, that is, semantic Web techniques, to shed a new light on the solutions for local e-government
information portal. After taking the comparison between traditional approaches and semantic approaches, the design of architecture
and components of a local e-government information portal are illustrated in details based on semantic technologies. The paper
also researches on the core technologies of implementation of the new approach, including the definition of e-government information
portal Ontologies and searching algorithms.
Access to XML-based documents currently relies on query languages that are closely tied to the document structures, i.e. when looking for information one has to be aware of this structure and cannot easily specify the information needs conceptually. Our approach uses ontologies to access sets of distributed XML documents on a conceptual level. We integrate conceptual modeling, inheritance, and inference mechanisms on the one hand with the popularity, simplicity, and flexibility of XML on the other hand. We present an approach that defines the relationship between a given ontology and a document type definition (DTD) for classes of XML documents. Thus, we are able to supplement syntactical access to XML documents by conceptual, i.e. real semantic access.
An important application of XML is the interchange of electronic data (EDI) between multiple data sources on the Web. As XML data proliferates on the Web, applications will need to integrate and aggregate data from multiple source and clean and transform data to facilitate exchange. Data extraction, conversion, transformation, and integration are all well-understood database problems, and their solutions rely on a query language. We present a query language for XML, called XML-QL, which we argue is suitable for performing the above tasks. XML-QL is a declarative, `relational complete' query language and is simple enough that it can be optimized. XML-QL can extract data from existing XML documents and construct new XML documents.
The paper argues for the use of general and intuitive knowledge representation languages (and simpler notational variants, e.g. subsets of natural languages) for indexing the content of Web documents and representing knowledge within them. We believe that these languages have advantages over metadata languages based on the Extensible Mark-up Language (XML). Indeed, the retrieval of precise information is better supported by languages designed to represent semantic content and support logical inference, and the readability of such a language eases its exploitation, presentation and direct insertion within a document (thus also avoiding information duplication). We advocate the use of Conceptual Graphs and simpler notational variants that enhance knowledge readability. To further ease the representation process, we propose techniques allowing users to leave some knowledge terms undeclared. We also show how lexical, structural and knowledge-based techniques may be combined to retrieve or generate knowledge or Web documents. To support and guide the knowledge modeling approach, we present a top-level ontology of 400 concept and relation types. We have implemented these features in a Web-accessible tool named WebKB2, and show examples to illustrate them.
Recent emerging technologies such as internetworking and the World Wide Web (WWW) have significantly expanded the types, availability, and volume of data accessible to an information management system. In this new environment it is imperative to view an information source at the level of its relevant semantic concepts. We propose that these semantic concepts be chosen from pre-existing domain specific ontologies. Domain specific ontologies are used as tools/mechanisms for specifying the ontological commitments or agreements between information users and providers on the information infrastructure. We use domain specific ontologies to tackle the information explosion by the: (a) Re-use and organization of knowledge in pre-existing real world ontologies, achieved by mapping semantic concepts in the ontologies to data structures in the underlying repositories; and (b) Knowledge integration and development of mechanisms to translate information requests across ontologies. We thus provide support for multiple domain specific ontologies as alternate world views on the vast amounts of data. Semantic information brokering is implemented by brokering across domain ontologies based on interontology relationships such as synonyms, hyponyms and hypernyms defined between terms in different ontologies. Information requests are rewritten using these relationships to obtain translations across ontologies.
Mediator modules comprise a layer of intelligent middleware services in information systems, linking data resources and application programs. Earlier programs that led to the concept of mediation were either constructed to support specific applications or provided extended services from databases. Intelligent mediators are being built now by careful domain knowledge acquisition and hand crafting the required code. In this paper we present the conceptual underpinning for automating the mediation process. Automation does not extend to fully automatic code generation, since additional knowledge is necessary to provide added value. The generation concept is based on the extraction of a hierarchical domain model out of the general network representing the available resources. Associated with the method are domain ontologies. Ontologies list the terms used by the models, and document their relationships. These terms provide the semantic foundation needed to perform the generation...
This paper describes SHOE, a set of Simple HTML Ontology Extensions which allow World-Wide Web authors to annotate their pages with semantic knowledge such as "I am a graduate student" or "This person is my graduate advisor". These annotations are expressed in terms of ontological knowledge which can be generated by using or extending standard ontologies available on the Web. This makes it possible to ask Web agent queries such as "Find me all graduate students in Maryland who are working on a project funded by DoD initiative 123-4567", instead of simplistic keyword searches enabled by current search engines. We have also developed a web-crawling agent, Expos e, which interns SHOE knowledge from web documents, making these kinds queries a reality. Introduction Imagine that you are searching the World-Wide Web for the home pages of a Mr. and Mrs. Cook, whom you met at a conference last year. You don't remember their first names, but you do recall that both work for an em...
The present paper gives a brief description of the Math-Net project which is carried out by nine mathematical institutions in Germany, supported by Deutsches Forschungsnetz (DFN) and Deutsche Telekom. The project aims at setting up the technical and organizational infrastructure for efficient, inexpensive and user-driven information services for mathematics. With the aid of active (structured retrieval mechanisms) and passive (profile services) components, electronic mathematical information in Germany will be made available to the scientist at his workplace. The emphasis is put on information about publications, software and data collections, teaching and research activities, but also on organizational and bibliographical information. Decentral organization structures, distributed search systems as well as the use of meta-information (metadata) in accordance with the Dublin Core (hopefully) guarantee a longterm, high-quality repository of data. The well-known mathematical software and data collection netlib will be used as an example to illustrate how such a collection can be adapted to Math-Net. An integration of netlib into HyperWave offers additional perspectives and functionalities.
In this paper, we present the W4F toolkit for the generation of wrappers for Web sources. W4F consists of a retrieval language to identify Web sources, a declarative extraction language (the HTML Extraction Language) to express robust extraction rules and a mapping interface to export the extracted information into some userdefined data-structures. To assist the user and make the creation of wrappers rapid and easy, the toolkit offers some wysiwyg support via some wizards. Together, they permit the fast and semi-automatic generation of ready-to-go wrappers provided as Java classes. W4F has been successfully used to generate wrappers for database systems and software agents, making the content of Web sources easily accessible to any kind of application.
We present a new focus+context (fisheye) technique for visualizing and manipulating large hierarchies. Our technique assigns more display space to a portion of the hierarchy while still embedding it in the context of the entire hierarchy. The essence of this scheme is to lay out the hierarchy in a uniform way on a hyperbolic plane and map this plane onto a circular display region. This supports a smooth blending between focus and context, as well as continuous redirection of the focus. We have developed effective procedures for manipulating the focus using pointer clicks as well as interactive dragging, and for smoothly animating transitions across such manipulation. A laboratory experiment comparing the hyperbolic browser with a conventional hierarchy browser was conducted.
Domain-specific search engines are becoming increasingly popular because they offer increased accuracy and extra features not possible with general, Web-wide search engines. Unfortunately, they are also difficult and timeconsuming to maintain. This paper proposes the use of machine learning techniques to greatly automate the creation and maintenance of domain-specific search engines. We describe new research in reinforcement learning, text classification and information extraction that enables efficient spidering, populates topic hierarchies, and identifies informative text segments. Using these techniques, we have built a demonstration system: a search engine for computer science research papers available at www.cora.justresearch.com. 1 Introduction As the amount of information on the World Wide Web grows, it becomes increasingly difficult to find just what wewant. While general-purpose search engines suchas AltaVista and HotBot offer high coverage, they often provi...
We propose a novel formalism, called Frame Logic (abbr., F-logic), that accounts in a clean and declarative fashion for most of the structural aspects of object-oriented and frame-based languages. These features include object identity, complex objects, inheritance, polymorphic types, query methods, encapsulation, and others. In a sense, F-logic stands in the same relationship to the object-oriented paradigm as classical predicate calculus stands to relational programming. F-logic has a model-theoretic semantics and a sound and complete resolution-based proof theory. A small number of fundamental concepts that come from object-oriented programming have direct representation in F-logic; other, secondary aspects of this paradigm are easily modeled as well. The paper also discusses semantic issues pertaining to programming with a deductive object-oriented language based on a subset of F-logic.
The technology for building large knowledge bases (KBs) is yet to witness a breakthrough so that a KB can be constructed by the assembly of prefabricated knowledge components. Knowledge components include both pieces of domain knowledge (for example, theories of economics or fault diagnosis) and KB tools (for example, editors and theorem provers). Most of the current KB development tools can only manipulate knowledge residing in the knowledge representation system (KRS) for which the tools were originally developed. Open Knowledge Base Connectivity (OKBC) is an application programming interface for accessing KRSs, and was developed to enable the construction of reusable KB tools. OKBC improves upon its predecessor, the Generic Frame Protocol (GFP), in several significant ways. OKBC can be used with a much larger range of systems because its knowledge model supports an assertional view of a KRS. OKBC provides an explicit treatment of entities that are not frames, and ...
Managing Web sites is a tedious data-management task, because today's Web sites often are derived from multiple data sources and have complex structures. To simplify these tasks, Web-site builders need tools for managing Web sites' content and structure. The Strudel system applies concepts from database management systems to the process of building Web sites. The key idea is separating the management of the site's data, the creation and management of the site's structure, and the graphical presentation of the site's pages. First, the site builder creates a uniform model of all the data available at the site. Second, the site builder uses this model to declaratively define the Web site's structure by applying a "site-definition query" to the underlying data. The result of evaluating this query is a "site graph", which represents both the site's content and structure. Third, the site builder specifies the graphical presentation of pages in Strudel's HTML-template language. The ...
To support the sharing and reuse of formally represented knowledge among AI systems, it is useful to define the common vocabulary in which shared knowledge is represented. A specification of a representational vocabulary for a shared domain of discourse—definitions of classes, relations, functions, and other objects—is called an ontology. This paper describes a mechanism for defining ontologies that are portable over representation systems. Definitions written in a standard format for predicate calculus are translated by a system called Ontolingua into specialized representations, including frame-based systems as well as relational languages. This allows researchers to share and reuse ontologies, while retaining the computational benefits of specialized implementations.We discuss how the translation approach to portability addresses several technical problems. One problem is how to accommodate the stylistic and organizational differences among representations while preserving declarative content. Another is how to translate from a very expressive language into restricted languages, remaining system-independent while preserving the computational efficiency of implemented systems. We describe how these problems are addressed by basing Ontolingua itself on an ontology of domain-independent, representational idioms.
The Internet presents numerous sources of useful information—telephone directories, product catalogs, stock quotes, event listings, etc. Recently, many systems have been built that automatically gather and manipulate such information on a user's behalf. However, these resources are usually formatted for use by people (e.g., the relevant content is embedded in HTML pages), so extracting their content is difficult. Most systems use customized wrapper procedures to perform this extraction task. Unfortunately, writing wrappers is tedious and error-prone. As an alternative, we advocate wrapper induction, a technique for automatically constructing wrappers. In this article, we describe six wrapper classes, and use a combination of empirical and analytical techniques to evaluate the computational tradeoffs among them. We first consider expressiveness: how well the classes can handle actual Internet resources, and the extent to which wrappers in one class can mimic those in another. We then turn to efficiency: we measure the number of examples and time required to learn wrappers in each class, and we compare these results to PAC models of our task and asymptotic complexity analyses of our algorithms. Summarizing our results, we find that most of our wrapper classes are reasonably useful (70% of surveyed sites can be handled in total), yet can rapidly learned (learning usually requires just a handful of examples and a fraction of a CPU second per example).
Ontologies are becoming increasingly more important in many different areas, including the knowledge management area. In knowledge management, ontologies can be used as an instrument to make knowledge assets intelligently accessible to people in organizations through an Intranet or the Internet. Most enterprises agree that knowledge is an essential asset for success and survival on an increasingly competitive and global market. In this paper, we present an ontology-based approach through a large-scale initiative involving knowledge management for the knowledge-acquisition research community.
RiboWeb is an online data resource for the ribosome, a vital
cellular apparatus. It contains a large knowledge base of relevant
published data and computational modules that can process this data to
test hypotheses about the ribosome's structure
. The World Wide Web (WWW) can be viewed as the largest multimedia database that has ever existed. However, its support for query answering and automated inference is very limited. Metadata and domain specific ontologies were proposed by several authors to solve this problem. We developed Ontobroker which uses formal ontologies to extract, reason, and generate metadata in the WWW. The paper describes the formalisms and tools for formulating queries, defining ontologies, extracting metadata, and generating metadata in the format of the Resource Description Framework (RDF), as recently proposed by the World Wide Web Consortium (W3C). These methods provide a means for semantic based query handling even if the information is spread over several sources. Furthermore, the generation of RDF descriptions enables the exploitation of the ontological information in RDF-based applications.
The World Wide Web (WWW) is currently one of the most important electronic information sources. However, its query interfaces and the provided reasoning services are rather limited. Ontobroker consists of a number of languages and tools that enhance query access and inference service of the WWW. The technique is based on the use of ontologies. Ontologies are applied to annotate web documents and to provide query access and inference service that deal with the semantics of the presented information. In consequence, intelligent brokering services for web documents can be achieved without requiring to change the semiformal nature of web documents. Introduction The World Wide Web (WWW) contains huge amounts of knowledge about almost all subjects you can think of. HTML documents enriched by multi-media applications provide knowledge in different representations (i.e., text, graphics, animated pictures, video, sound, virtual reality, etc.). Hypertext links between web documents ...
KBS-Hyperbook - an open hyperbook system for education
- P Fröhlich
- W Neijdl
- M Wolpers
P. Frö, W. Neijdl and M. Wolpers, KBS-Hyperbook — an open hyperbook system for education, in: Proc. 10th World Conf. on Educational Media and Hypermedia (EDMEDIA'98), Freiburg, 1998.
OKBC: a programmatic foundation for knowledge base interoperability
- V Chaudri
- A Farquhar
- R Fikes
- P Karp
- J Rice