Internet Draft Wang Liang Document: draft-liang-irpdl-00.txt hust Expires: March 2003 September 2003 Information Retrieval Protocol for Digital Library draft-liang-irpdl-00.txt Status of this Memo This document is an Internet-Draft and is in full conformance with all provisions of Section 10 of RFC2026. Internet-Drafts are working documents of the Internet Engineering Task Force (IETF), its areas, and its working groups. Note that other groups may also distribute working documents as Internet-Drafts. Internet-Drafts are draft documents valid for a maximum of six months and may be updated, replaced, or obsoleted by other documents at any time. It is inappropriate to use Internet-Drafts as reference material or to cite them other than as "work in progress." The list of current Internet-Drafts can be accessed at http://www.ietf.org/ietf/1id-abstracts.txt. The list of Internet-Draft Shadow Directories can be accessed at http://www.ietf.org/shadow.html. This Internet-Draft will expire on March 10, 2004. Copyright Notice Copyright (C) The Internet Society (2003). All Rights Reserved. Abstract This document specifies an information retrieval protocol for digital library. This protocol has two parts: standard search Webservice for heterogeneous databases and the method to find and select such search Webservice. By using this protocol, all the databases including web page database, digital issue database, and video database, can release the uniform search Webservice, though these databases may have different metadata standards and architecture. And these Webservice can be easily found and visited by search systems. This very protocol makes it possible that users can obtain all kinds of information on the Internet in single search engine, but not visit lots of different search engines one by one. WANG Expires - March 10,2004 [Page 1] Internet Draft Information RPDL September 2003 1. Introduction Hundreds of databases have been introduced in many libraries, and there are many more free information resources on the Internet. It has become a kind of acrobatics for us to find the complete and precise results about our query in so many databases. Everyone hopes to obtain all kinds of information in one search engine, such as web pages, Videos, but does not care where the information lies in. Webservice [1] give us a good method to realize this desire. As long as these databases can provide Webservice, it will be an easy mission to integrate all kinds of information resources in one search engine. Now Google [2] and some other databases have provided search Webservice. But standard protocol for these searches Webservice does not exist. Even different web search engines Webservice have distinct formats of queries and search results, needless to mention the Webservice of many other kinds of databases. Thus, a uniform Webservice applicable for all the information resources and an efficient method to find such Webservice should be established. This document just achieves these two goals. The protocol comprises of two interacting parts, Standard Search Webservice (SSW) which can be applied to all databases and Search Webservice Description, Discovery and Integration (SDDI) which provides an efficient way to find the appropriate search Webservice. 2 Standard Searches Webservice Information Retrieval Protocol defines a standard search Webservice with its classes and functions. Most of databases can distribute the uniform search Webservice by using this definition. 2.1 data encoding In order to support searching documents in multiple languages, all requests and responses should be in accordance with the UTF-8 encoding. 2.2. The format of query words Query words are applied to present request. The query words can include the logical operator Boolean OR: "OR" A OR B: A or B must appear in the results Boolean AND: "AND" A AND B: A and B must appear in the results Boolean NOT: "NOT" NOT A: the word A can't appear in the results The logical operator can be used together. WANG Expires - March 10, 2004 [Page 2] Internet Draft Information RPDL September 2003 For example: (A AND B) AND (NOT C) means the results must include A and B but can't have C. The character "("and ")" in the query words will be treated as word separators. 2.3 class and function The standard Webservice with its class structures and functions are detailed here and also presented in the form of WSDL [3]. There are three function components in a search Webservice.1 receive the query words and return results.2 analyze and explain the results. 3 depict every recorder of the results. All these functions are implemented with three classes of Webservice. 2.3.1 Class Search Main function of this class is to submit a query string and a set of parameters to the search service and receive in return a set of search results. There are three levels of search function in this class: basic search, advanced search, full search. a. Basic search basicSearch(title.start,maxResults) title: query words; represent the basic description of a recorder. Field "title" is available in all the metadata and databases. Book, video, webpage database all can provide the search in "title" start: Zero-based index of the first desired result. maxResults: Number of results desired per query. The maximum value per query set to 100, and the minimum is defined as 10. If you make a query that doesn't have many matching items, the actual number of results you get may be smaller than that of you request. b. Advanced search advanceSearch(title,keywords,author,abstract, dateStart,dateEnd,start,maxResults,order) the meaning of title start maxResult is just the same as those in Basic search. The reason to select the keywords, author, and date as the search fields is that these fields are normally available in most databases and metadata. WANG Expires - March 10,2004 [Page 3] Internet Draft Information RPDL September 2003 keywords: query words, keywords for recorder author : query words, author of the recorder. abstract: the basic description of the recorder. dateStart,dateEnd: present date range. If you want to limit your results to document that are published within a specific date range, you can use this query term to accomplish this. Order: the sort order of the results. It can be "date" which means sorting by date or "correlativity" which means sorting by correlativity, or some other orders else. c. Full search fullSearch(" ", start, maxResults) Full search will provides all the query formats of one database. They will be confirmed by the database owners. 2.3.2 Class SearchResponse Each time you issue a search request to the search service, a response is returned back to you. This class describes the meanings of the values returned to you. The character of this class is described as follows. TotalResultsCount: The estimated total number of results that exist for the query. resultElements: An array of "resultElement" items. This corresponds to the actual list of search results. startIndex:Indicates the index (1-based) of the first search result in "resultElements". endIndex: Indicates the index (1-based) of the last search result in "resultElements". searchTime :Text, floating-point number indicating the total server time to return the search results, which measured in seconds. 2.3.3 Class ResultElement This class describes every record in return results. This Class has three characters as follows. Sourcename: name of the information source. WANG Expires - March 10,2004 [Page 4] Internet Draft Information RPDL September 2003 Title: title of the recorder. URL: The URL of the recorder, returned as text, with an absolute URL path. Otherinformation: some information such as a snippet of a webpage, author of the recorder. This character will be defined according to different search Webservice. 2.3.4 WSDL of standard search Webservice WANG Expires - March 10,2004 [Page 5] Internet Draft Information RPDL September 2003 ...... WANG Expires - March 10,2004 [Page 6] Internet Draft Information RPDL September 2003 WANG Expires - March 10,2004 [Page 7] Internet Draft Information RPDL September 2003 3 the description of the search Webservice To describe the search Webservice, we refer to the UDDI[4]. Search Webservice Description, Discovery and Integration (SDDI) is proposed in this part. SDDI will help the search system find and select the appropriate data sources. 3.1 The XML schema of the SDDI We use the DC[5] standard to descript the character of the search Webservice. 9 of 15 sub elements of DC are selected and divided into three groups. The other basic information for a web service is also added in the SDDI. Because all the search services use the uniform standard Webservice, the business service, binding template and Model in UDDI will be useless in SDDI. The information like BusinessEntity in UDDI is enough to identify a search Webservice. The elements and attributes to describe a search Webservice are represented as follows. 1 content Title: A name given to the resource. Description: An account of the content of the resource. Language: A language of the intellectual content of the resource. 2 copyright Creator: An entity primarily responsible for making the content of the resource. Publisher: An entity responsible for making the resource available Rights: Information about rights held in and over the resource. 3 characters Date: A date of an event in the lifecycle of the resource Format: The physical or digital manifestation of the resource. Identifier: An unambiguous reference to the resource within a given context. 4 UDDI: Key the UDDI content of this Webservice if available. WANG Expires - March 10,2004 [Page 8] Internet Draft Information RPDL September 2003 5 categorybag: This is an optional list of name-value pairs that are used to tag a search Webservice with specific taxonomy information. Some classification methods according to subjects can be adopted, such as (CLC) Chinese Library Classification (LCC) Library of Congress Classification. 6 accesspoint: URL of this Webservice The XML schema of SDDI as follow. WANG Expires - March 10,2004 [Page 9] Internet Draft Information RPDL September 2003 3.2 The API of SDDI 3.2.1 Publish When a library purchase a database, a SDDI of this database will be authorized at the same time and saved at the local servers. The library can revise the SDDI itself according to its own needs. 3.2.2 Inquiry API Inquiry API will provide two simple functions that help the search engine find the appreciate Webservice that matches the requirements of users. The definition of element should refer the SDDI. Meanwhile, the element can have complex structure. 1 find(element,value) Return the accesspoint according to the element and its value. For example: find(copyright, "Tom", "publisher","right") find(title, "ACM") 2 get(element1,value,element2) Return the value of element2 according to the value of element1.For example: Get((title, "ACM", character) Security Considerations The security considerations should refer to those of Webservice. There are no any additional security concerns in this protocol. WANG Expires - March 10,2004 [Page 10] Internet Draft Information RPDL September 2003 References [1] Webservice , http://www.w3.org/2002/ws/ [2] The web service of Google, http://www.google.com/apis/ [3] WSDL, http://www.w3.org/TR/wsdl [4] UDDI, http://www.uddi.org [5] S. Weibel, J. Kunze, "Dublin Core Metadata for Resource Discovery", rfc2413, September 1998. Author's Addresses Wang liang HUST WUHAN 430074 China Phone: 86-27-87553494 Email:wangliang_f@163.com Guo YiPing HUST WUHAN 430074 China Email:wangliang_f@163.com Fang Ming HUST WUHAN 430074 China Email:fangming_w@263.net Xu Yuedong HUST WUHAN 430074 China Email: xuyaodong2000@yahoo.com.cn WANG Expires - March 10,2004 [Page 11] Internet Draft Information RPDL September 2003 Full Copyright Statement Copyright (C) The Internet Society (2003). All Rights Reserved. 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