Search (28 results, page 1 of 2)

  • × theme_ss:"Verteilte bibliographische Datenbanken"
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  1. Avrahami, T.T.; Yau, L.; Si, L.; Callan, J.P.: ¬The FedLemur project : Federated search in the real world (2006) 0.14
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    Abstract
    Federated search and distributed information retrieval systems provide a single user interface for searching multiple full-text search engines. They have been an active area of research for more than a decade, but in spite of their success as a research topic, they are still rare in operational environments. This article discusses a prototype federated search system developed for the U.S. government's FedStats Web portal, and the issues addressed in adapting research solutions to this operational environment. A series of experiments explore how well prior research results, parameter settings, and heuristics apply in the FedStats environment. The article concludes with a set of lessons learned from this technology transfer effort, including observations about search engine quality in the real world.
    Date
    22. 7.2006 16:02:07
  2. Krause, J.: Heterogenität und Integration : Zur Weiterentwicklung von Inhaltserschließung und Retrieval in sich veränderten Kontexten (2001) 0.08
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    Abstract
    As an important support tool in science research, specialized information systems are rapidly changing their character. The potential for improvement compared with today's usual systems is enormous. This fact will be demonstrated by means of two problem complexes: - WWW search engines, which were developed without any government grants, are increasingly dominating the scene. Does the WWW displace information centers with their high quality databases? What are the results we can get nowadays using general WWW search engines? - In addition to the WWW and specialized databases, scientists now use WWW library catalogues of digital libraries, which combine the catalogues from an entire region or a country. At the same time, however, they are faced with highly decentralized heterogeneous databases which contain the widest range of textual sources and data, e.g. from surveys. One consequence is the presence of serious inconsistencies in quality, relevance and content analysis. Thus, the main problem to be solved is as follows: users must be supplied with heterogeneous data from different sources, modalities and content development processes via a visual user interface without inconsistencies in content development, for example, seriously impairing the quality of the search results, e. g. when phrasing their search inquiry in the terminology to which they are accustomed
  3. Croft, W.B.: Combining approaches to information retrieval (2000) 0.07
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    Abstract
    The combination of different text representations and search strategies has become a standard technique for improving the effectiveness of information retrieval. Combination, for example, has been studied extensively in the TREC evaluations and is the basis of the "meta-search" engines used on the Web. This paper examines the development of this technique, including both experimental results and the retrieval models that have been proposed as formal frameworks for combination. We show that combining approaches for information retrieval can be modeled as combining the outputs of multiple classifiers based on one or more representations, and that this simple model can provide explanations for many of the experimental results. We also show that this view of combination is very similar to the inference net model, and that a new approach to retrieval based on language models supports combination and can be integrated with the inference net model
  4. Smith, N.: Z39.50 and the OPAC Network in Europe (ONE) Project (1996) 0.06
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    Abstract
    Examines the use of the Z39.50 Information Retrieval protocol for provision of access to its collections. Z39.50 offers a translation of different search engines developed by library systems suppliers and online database hosts. Traces its development and describes its abstraction and metalanguage, and the TCP/IP and OSI layer. It is being further developed in project ONE - OPAC Network in Europe, and European Union Library Plan project which began in Jan 95, of which the British Library is a partner. It aims to link national library catalogues in an open standards and telecommunications network, and to achieve interoperability by use of Z39.50. Describes the project so far, agreements made, and future developments
  5. Ashton, J.: ONE: the final OPAC frontier (1998) 0.05
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    Abstract
    Describes the European Commission's OPAC Network in Europe (ONE) project which attempts to make it simpler to search a number of major European OPACs crossing all frontiers via online interface. Explains how this is done and the British Library's involvement in it, assessment of the project and plans for the future
    Source
    Select newsletter. 1998, no.22, Spring, S.5-6
  6. Burrows, T.: ¬The virtual catalogue : bibliographic access for the virtual library (1993) 0.05
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    Abstract
    Proposes a new model for bibliographic access, the virtual catalogue, to serve the virtual library. Suggests the use of current software and networks to build links between bibliographic databases of all kinds, including full text, to enable the user to search a specified subset of databases. Suggests that local data be limited to holdings information linked to, but separate from, bibliographic databases both local and remote
    Date
    8.10.2000 14:47:22
  7. Johnson, E.H.: Objects for distributed heterogeneous information retrieval (2000) 0.05
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    Abstract
    The success of the World Wide Web Shows that we can access, search, and retrieve information from globally distributed databases. lf a database, such as a library catalog, has some sort of Web-based front end, we can type its URL into a Web browser and use its HTML-based forms to search for items in that database. Depending an how well the query conforms to the database content, how the search engine interprets the query, and how the server formats the results into HTML, we might actually find something usable. While the first two issues depend an ourselves and the server, an the Web the latter falls to the mercy of HTML, which we all know as a great destroyer of information because it codes for display but not for content description. When looking at an HTML-formatted display, we must depend an our own interpretation to recognize such entities as author names, titles, and subject identifiers. The Web browser can do nothing but display the information. lf we want some other view of the result, such as sorting the records by date (provided it offers such an option to begin with), the server must do it. This makes poor use of the computing power we have at the desktop (or even laptop), which, unless it involves retrieving more records, could easily do the result Set manipulation that we currently send back to the server. Despite having personal computers wich immense computational power, as far as information retrieval goes, we still essentially use them as dumb terminals.
    Date
    22. 9.1997 19:16:05
  8. Nicholson, D.; Steele, M.: CATRIONA : a distributed, locally-oriented, Z39.50 OPAC-based approach to cataloguing the Internet (1996) 0.04
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    Abstract
    The aims of CATRIONA were: (1) to investigate the requirements for developing procedures and applications for cataloguing and retrieval of networked resources, and (2) to explore the feasibility of a collaborative project to develop such applications and procedures and integrate them with existing library systems. The project established that a distributed catalogue of networked resources integrated with standard Z39.50 library system OPAC interfaces with information on hard-copy resources is already a practical proposition at a basic level. At least one Z39.50 OPAC client can search remote Z39.50 OPACs, retrieve USMARC records with URLs in 856$u, load a viewer like Netscape, and use it to retrieve and display the remotely held electronic resource on the local workstation. A follow-up project on related issues is being finalised.
    Source
    Cataloging and classification quarterly. 22(1996) nos.3/4, S.127-141
  9. Teets, M.; Murray, P.: Metasearch authentication and access management (2006) 0.03
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    Abstract
    Metasearch - also called parallel search, federated search, broadcast search, and cross-database search - has become commonplace in the information community's vocabulary. All speak to a common theme of searching and retrieving from multiple databases, sources, platforms, protocols, and vendors at the point of the user's request. Metasearch services rely on a variety of approaches including open standards (such as NISO's Z39.50 and SRU/SRW), proprietary programming interfaces, and "screen scraping." However, the absence of widely supported standards, best practices, and tools makes the metasearch environment less efficient for the metasearch provider, the content provider, and ultimately the end-user. To spur the development of widely supported standards and best practices, the National Information Standards Organization (NISO) sponsored a Metasearch Initiative in 2003 to enable: * metasearch service providers to offer more effective and responsive services, * content providers to deliver enhanced content and protect their intellectual property, and * libraries to deliver a simple search (a.k.a. "Google") that covers the breadth of their vetted commercial and free resources. The Access Management Task Group was one of three groups chartered by NISO as part of the Metasearch Initiative. The focus of the group was on gathering requirements for Metasearch authentication and access needs, inventorying existing processes, developing a series of formal use cases describing the access needs, recommending best practices given today's processes, and recommending and pursing changes to current solutions to better support metasearch applications. In September 2005, the group issued their final report and recommendation. This article summarizes the group's work and final recommendation.
  10. Veen, T. van; Oldroyd, B.: Search and retrieval in The European Library : a new approach (2004) 0.03
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    Abstract
    The objective of the European Library (TEL) project [TEL] was to set up a co-operative framework and specify a system for integrated access to the major collections of the European national libraries. This has been achieved by successfully applying a new approach for search and retrieval via URLs (SRU) [ZiNG] combined with a new metadata paradigm. One aim of the TEL approach is to have a low barrier of entry into TEL, and this has driven our choice for the technical solution described here. The solution comprises portal and client functionality running completely in the browser, resulting in a low implementation barrier and maximum scalability, as well as giving users control over the search interface and what collections to search. In this article we will describe, step by step, the development of both the search and retrieval architecture and the metadata infrastructure in the European Library project. We will show that SRU is a good alternative to the Z39.50 protocol and can be implemented without losing investments in current Z39.50 implementations. The metadata model being used by TEL is a Dublin Core Application Profile, and we have taken into account that functional requirements will change over time and therefore the metadata model will need to be able to evolve in a controlled way. We make this possible by means of a central metadata registry containing all characteristics of the metadata in TEL. Finally, we provide two scenarios to show how the TEL concept can be developed and extended, with applications capable of increasing their functionality by "learning" new metadata or protocol options.
  11. Stark, T.: ¬The Net and Z39.50 : toward a virtual union catalog (1997) 0.02
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    Abstract
    The State Library of Iowa, USA, received a Higher Education Act title II grant from the US Dept. of Education in 1994 to create a demonstration project of new library information technologies. Describes 2 interlinked components of the project: Web-based union catalogue development and statewide deployment of the ANSI/NISO Z39.50 standard for database search and retrieval. Z39.50 was chosen because of its ability to searching multiple remote databases in a single session and its common interface across a variety of implementations. Use of a distributed Z39.50 search makes the need for maintaining large union catalogues unnecessary
  12. SRW/U erleichtert verteilte Datenbankrecherchen (2005) 0.02
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    Content
    "Seit zwei Jahrzehnten nutzen vor allem Bibliotheksverbünde das Protokoll Z39.50, um ihren Benutzern im Internet die simultane Abfrage mehrerer Datenbanken zu ermöglichen. Jetzt gibt es einen Nachfolger dieses Protokolls, der eine einfachere Implementierung verspricht. Damit ist auch eine größere Verbreitung für die Suche in verteilten Datenbeständen anderer Institutionen, wie z.B. Archiven und Museen, wahrscheinlich. SRW/U (Search and Retrieve Web Service bzw. Search and Retrieve URL Service, www.loc.90v/z3950/agency/zing/srw) wurde von einer an der Library of Congress angesiedelten Initiative entwickelt und beruht auf etablierten Standards wie URI und XML. Die mit SRW und SRU möglichen Abfragen und Ergebnisse unterscheiden sich nur in der Art der Übertragung, verwenden aber beide dieselben Prozeduren. Davon gibt es nur drei: explain, scan und searchRetrieve. Die beiden Erstgenannten dienen dazu, allgemeine Informationen über den Datenanbieter bzw. die verfügbaren Indexe zubekommen. Das Herzstück ist die search-Retrieve-Anweisung. Damit werden Anfragen direkt an die Datenbank gesendet und die Parameter des Suchergebnisses definiert. Verwendet wird dafür die Retrievalsprache CQL (Common Query Language), die simple Freitextsuchen, aber auch mit Boolschen Operatoren verknüpfte Recherchen ermöglicht. Bei SRU werden die Suchbefehle mittels einfacher HTTP GET -Anfragen übermittelt, die Ergebnisse in XML zurückgeliefert. Zur Strukturierung der Daten dienen z.B. Dublin Core, MARC oder EAD. Welches Format von der jeweiligen Datenbank bereitgestellt wird, kann durch die explain-Anweisung ermittelt gebracht werden."
  13. Fang, L.: ¬A developing search service : heterogeneous resources integration and retrieval system (2004) 0.02
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    Abstract
    This article describes two approaches for searching heterogeneous resources, which are explained as they are used in two corresponding existing systems-RIRS (Resource Integration Retrieval System) and HRUSP (Heterogeneous Resource Union Search Platform). On analyzing the existing systems, a possible framework-the MUSP (Multimetadata-Based Union Search Platform) is presented. Libraries now face a dilemma. On one hand, libraries subscribe to many types of database retrieval systems that are produced by various providers. The libraries build their data and information systems independently. This results in highly heterogeneous and distributed systems at the technical level (e.g., different operating systems and user interfaces) and at the conceptual level (e.g., the same objects are named using different terms). On the other hand, end users want to access all these heterogeneous data via a union interface, without having to know the structure of each information system or the different retrieval methods used by the systems. Libraries must achieve a harmony between information providers and users. In order to bridge the gap between the service providers and the users, it would seem that all source databases would need to be rebuilt according to a uniform data structure and query language, but this seems impossible. Fortunately, however, libraries and information and technology providers are now making an effort to find a middle course that meets the requirements of both data providers and users. They are doing this through resource integration.
  14. Lynch, C.A.: Building the infrastructure of resource sharing : union catalogs, distributed search, and cross database linkage (1997) 0.02
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    Abstract
    Effective resourcesharing presupposes an infrastructure which permits users to locate materials of interest in both print and electronic formats. 2 approaches for providing this are union catalogues and Z39.50 based distributed search systems and computer to computer information retrieval protocols. The advantages and limitations of each approach are considered, paying particular attention to a relaistic assessment of Z39.50 implementations. Argues that the union catalogue is far from obsolete and the 2 approaches should be considered complementary rather than competitive. Technologies to create links between the bibliographic apparatus of catalogues and abstracting and indexing databases and primary content in electronic form, such as the new Serial Item and Contribution Identifier (SICI) standard are also discussed as key elements in the infrastructure to support resource sharing
  15. Smith, N.A.: ONE, OPAC network in Europe : taking a further step towards a Europe-wide information network (1995) 0.02
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    Abstract
    OPAC Network in Europe (ONE) is a project aimed at providing users with better ways to access library OPACs and national catalogues and which will stimulate and facilitate internetworking between libraries in Europe. The project is based on SR/Z39.50 standards which enable users to search widely different computer systems across networks and offer end users the promise of greater ease of use through a solution to the proliferation of different user interfaces to library catalogues
  16. Cousins, S.; Sanders, A.: Incorporating a virtual union catalogue into the wider information environment through the application of middleware: Interoperability issues in cross-database access (2006) 0.02
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    Abstract
    Purpose - To explore the use of middleware to provide access to a virtual catalogue via Z39.50, allowing its integration with other services. To consider issues arising from the cross-database search process and the problem of interoperability between systems. Design/methodology/approach - Middleware was used to establish a Z39.50 server for an existing virtual union catalogue, InforM25. The Copac physical union catalogue was used to carry out cross-database search tests, investigating the value of query transformation by the middleware and illustrating many of the issues associated with interoperability in cross-database searching. Findings - The test results demonstrate the viability and benefits of using middleware to allow the integration of virtual catalogues with other services. The results also illustrate the range of issues affecting the performance of the virtual catalogue, with supporting evidence from the use of the Copac physical union catalogue for cross-database searching via Z39.50. In particular the discussion highlights the issue of semantic interoperability, as well as emphasising the value of centralised virtual catalogue support. Research limitations/implications - The research was limited to work on a specific virtual union catalogue, that is InforM25, but the results highlight issues with general relevance in the development of any virtual catalogue. The need for more work on response times in the virtual union catalogue is apparent, along with the related issue of result set post processing. Originality/value - This paper provides a practical demonstration of the issues important to those involved in making their local catalogue accessible to services, and individuals, outside their own institution, as well as those working on virtual union catalogue development.
  17. Laegreid, J.A.: ¬The Nordic SR-net project : implementation of the SR/Z39.50 standards in the Nordic countries (1994) 0.02
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    Abstract
    The Nordic SR-net project started in 1991, with the aim to develop communications between university library systems and union catalogues in all five Nordic countries, based on the ISO protocol Search and Retrieve. The plan was to develop totally integrated solutions, where the use interface of the remote systems would be hidden, and users can use their own interfaces from their own home systems
  18. Kunz, M.: Subject retrieval in distributed resources : a short review of recent developments (2003) 0.02
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    Abstract
    Subject-based retrieval in distributed resources is a current problem in online searches for bibliographic references. Building portals to similar resources is only the ferst step, the subsequent navigation via different search interfaces presents certain difficulties. To make retrieval easier it is necessary to adapt these different resources. Potential approaches (standardisation as opposed to "cross-walks") and methods (automated as opposed to intellectual effort) will be discussed. This includes a Brief appraisal of the future of work with multilingual terminology: - The "classical" approach (Multilingual Thesauri), - The "Internet" approach (linking) Recent developments in mono- and multilingual environments will be presented (MACS, CARMEN, Economics Crosswalk).
  19. Xu, J.; Croft, W.B.: Topic-based language models for distributed retrieval (2000) 0.01
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    Abstract
    Effective retrieval in a distributed environment is an important but difficult problem. Lack of effectiveness appears to have two major causes. First, existing collection selection algorithms do not work well on heterogeneous collections. Second, relevant documents are scattered over many collections and searching a few collections misses many relevant documents. We propose a topic-oriented approach to distributed retrieval. With this approach, we structure the document set of a distributed retrieval environment around a set of topics. Retrieval for a query involves first selecting the right topics for the query and then dispatching the search process to collections that contain such topics. The content of a topic is characterized by a language model. In environments where the labeling of documents by topics is unavailable, document clustering is employed for topic identification. Based on these ideas, three methods are proposed to suit different environments. We show that all three methods improve effectiveness of distributed retrieval
  20. Roszkowski, M.; Lukas, C.: ¬A distributed architecture for resource discovery using metadata (1998) 0.01
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    Abstract
    This article describes an approach for linking geographically distributed collections of metadata so that they are searchable as a single collection. We describe the infrastructure, which uses standard Internet protocols such as the Lightweight Directory Access Protocol (LDAP) and the Common Indexing Protocol (CIP), to distribute queries, return results, and exchange index information. We discuss the advantages of using linked collections of authoritative metadata as an alternative to using a keyword indexing search-engine for resource discovery. We examine other architectures that use metadata for resource discovery, such as Dienst/NCSTRL, the AHDS HTTP/Z39.50 Gateway, and the ROADS initiative. Finally, we discuss research issues and future directions of the project. The Internet Scout Project, which is funded by the National Science Foundation and is located in the Computer Sciences Department at the University of Wisconsin-Madison, is charged with assisting the higher education community in resource discovery on the Internet. To that end, the Scout Report and subsequent subject-specific Scout Reports were developed to guide the U.S. higher education community to research-quality resources. The Scout Report Signpost utilizes the content from the Scout Reports as the basis of a metadata collection. Signpost consists of more than 2000 cataloged Internet sites using established standards such as Library of Congress subject headings and abbreviated call letters, and emerging standards such as the Dublin Core (DC). This searchable and browseable collection is free and freely accessible, as are all of the Internet Scout Project's services.
    As well developed as both the Scout Reports and Signpost are, they cannot capture the wealth of high-quality content that is available on the Internet. An obvious next step toward increasing the usefulness of our own collection and its value to our customer base is to partner with other high-quality content providers who have developed similar collections and to develop a single, virtual collection. Project Isaac (working title) is the Internet Scout Project's latest resource discovery effort. Project Isaac involves the development of a research testbed that allows experimentation with protocols and algorithms for creating, maintaining, indexing and searching distributed collections of metadata. Project Isaac's infrastructure uses standard Internet protocols, such as the Lightweight Directory Access Protocol (LDAP) and the Common Indexing Protocol (CIP) to distribute queries, return results, and exchange index or centroid information. The overall goal is to support a single-search interface to geographically distributed and independently maintained metadata collections.