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   Internet Draft                                      Wang Liang,et al
   Document: draft-ietf-liang-irpdl-03.txt                         hust
   Expires: April 2004                                    November 2003


           Information Retrieval Protocol for Digital Resources
                       draft-liang-irpdl-03.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 April 10, 2004.

Copyright Notice

   Copyright (C) The Internet Society (2003).  All Rights Reserved.


Abstract

   This document specifies an information retrieval protocol for
   heterogeneous information resources. This protocol has two parts:
   standard search Webservice, which defines the format of query words
   and the search results; and a 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 architectures. 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



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   information on Internet in single search engine, but not visit lots
   of different search engines one by one.
Conventions used in this document

   The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
   "SHOULD", "SHOULD NOT", "RECOMMENDED",  "MAY", and "OPTIONAL" in this
   document are to be interpreted as described in [RFC-2119].


Table of Contents

   1.Introduction .................................................2
   2.Standard Search Webservice....................................3
     2.1 Data encoding.............................................3
     2.2 The format of query words.................................3
     2.3 class and function........................................5
         2.3.1 Class Search........................................5
         2.3.2 Class Search Response...............................7
         2.3.3 Class Result Element................................7
     2.4 WSDL of standard search Webservice........................8
   3.The description of the search Webservice......................10
      3.1 The XML schema of the SDDI...............................11
      3.2 The API of SDDI..........................................14
          3.2.1 Publish............................................14
          3.2.2 Inquiry API........................................14
   4.Security consideration........................................15
   5.Reference.....................................................15
      5.1 Normative references.....................................15
      5.2 Informative references...................................15
   6.Author's Address..............................................15
   7. Copyright Statement..........................................16

1. Introduction

   Nowadays there are many kinds of information on Internet, such as web
   pages, FTP, and hundreds of databases in many libraries. It has
   become a kind of acrobatics for us to find the complete and precise
   results about our query form so many data resources. 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 [4] 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 [5] and some other databases have provided search
   Webservice. But standard protocol for these searches Webservice does
   not exist. Even different web search enginesÆ Webservice have
   distinct formats of queries and search results, needless to mention
   the Webservice of many other kinds of databases. Thus, a uniform


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   Webservice applicable for all the information resources and an
   efficient method to find such Webservice should be established. This
   memo 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

   Standard Searches Webservice 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

   The query words specify attribute based boolean queries. Different
   communities will require their own sets of attributes, so these query
   words is flexible enough to allow attributes from different
   communities.

   There are three kinds of query words : basicQuery, advancedQuery,
   fullQuery. The XML Schema of query word defined as follow.

   Element "logops" contains three logical operators
   "AND","NOT","OR".The XML Schema of "logops" is defined as follow.


   <xsd:simpleType name="logops">
   <xsd:restriction base="xsd:string">
   <xsd:enumeration value="AND">
   <xsd:enumeration value="NOT">
   <xsd:enumeration value="OR">
   </xsd:restriction>
   </xsd:simpleType>

   Element "operator" defines the string operation, whose value can be
   "contain", "equal" or "like".

   equal: operator that provide simple equality matching on property
   values.
   contain operator that search the documents that contain the special
   words.


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   like: operator that give simple wildcard-based pattern matching
   ability. Wildcard can be "?" or "%".The "?" wildcard matches exactly
   one character. The "%" wildcard matches zero or more characters.

   The XML schema of element "operator" is defined as follows.
   <xsd:simpleType name="operator">
   <xsd:restriction base="xsd:string">
   <xsd:enumeration value="contain">
   <xsd:enumeration value="equal">
   <xsd:enumeration value="like">
   </xsd:restriction>
   </xsd:simpleType>

   All the query words will be defined as a series of combination of
   logical operator, operator, and search field. For example:

   <logops>AND</logops>
   <oprator>contain<operator>
   <title>java</title>
   It represents that the title of result must contain the "java".

   The basicQuery is defined as follow. "title" represents 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".

   <xsd:complexType name="BasicQuery">
   <xsd:complexType name="field" minOccurs="0" maxOccurs="unbounded">
   <xsd:sequence>
   <xsd:element ref="logops">
   <xsd:element ref="operator">
   <xsd:element name="title" type="xsd:string">
   </xsd:sequence>
   </xsd:complexType>
   </xsd:complexType>


   The advancedQuery is defined as follow. Selecting element "title",
   "keywords", "author", "abstract" as the search fields is because
   these fields are normally available in most databases and metadata
   and represent the same meaning.

   <xsd:simpleType name="AdvancedField">
   <xsd:restriction base="xsd:string">
   <xsd:enumeration value="title">
   <xsd:enumeration value="keywords">
   <xsd:enumeration value="author">
   <xsd:enumeration value="abstract">
   </xsd:restriction>


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   </xsd:simpleType>

   <xsd:complexType name="advancedQuery">
   <xsd:complexType name="field" minOccurs="0" maxOccurs="unbounded">
   <xsd:sequence>
   <xsd:element ref="logops">
   <xsd:element ref="operator">
   <xsd:element ref="AdvancedField">
   </xsd:sequence>
   </xsd:complexType>
   </xsd:complexType>


   The fullQuery is defined as follow. FullQuery will provide all the
   search field of one database. They will be decided by the database
   owners.

   <xsd:simpleType name="FullField">
   <xsd:restriction base="xsd:string">
   <xsd:enumeration value="title">
   <xsd:enumeration value="keywords">
   <!--and so on-->
   </xsd:restriction>
   </xsd:simpleType>

   <xsd:complexType name="FullQuery">
   <xsd:complexType name="field" minOccurs="0" maxOccurs="unbounded">
   <xsd:sequence>
   <xsd:element ref="logops">
   <xsd:element ref="operator">
   <xsd:element ref="FullField">
   </xsd:sequence>
   </xsd:complexType>
   </xsd:complexType>

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 [1].

   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




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   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 according to the three
   kinds of query words in this class: basic search, advanced search,
   full search.

   a. Basic search

   basicSearch(
   query as basicQuery,
   start as integer,
   maxResults as Integer)

   query: XML format parameter, it accords with the different
   definitions of query words.

   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 1. 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

   advancedSearch(
   query as advancedQuery,
   dateStart as date,
   dateEnd as date,
   start as Integer,
   maxResults as Integer,
   orderby as String,
   order as string)


   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.

   orderby: the sort order of the results. It can be "date" which means
   sorting by date or "Relevance" which means sorting by the relation
   between results recorders and query, or "title", sorting by field
   "title".

   Order: can be "descending" or "ascending", recorders is sorted in
   descending or ascending.



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   c. Full search

   fullSearch(
   query as fullQuery,
    Start as Integer,
    maxResults as Integer,
   other parameters)

   Full search will provides all the query formats of one database. They
   will be guaranteed by the database owners.

2.3.2 Class Search Response

   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 characters of this class are
   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 Result Element

   This class describes every record in return results. This Class has
   three characters as follows.

   Sourcename: name of the information source.

   Title: title of the search 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.


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2.4 WSDL of standard search Webservice

   <definitions name="search"
   targetNamespace="databaseSearch "
   xmlns:typens=" databaseSearch "
   xmlns:xsd="http://www.w3.org/2001/XMLSchema"
   xmlns:soap="http://schemas.xmlsoap.org/wsdl/soap/"
   xmlns:soapenc="http://schemas.xmlsoap.org/soap/encoding/"
   xmlns:wsdl="http://schemas.xmlsoap.org/wsdl/"
   xmlns="http://schemas.xmlsoap.org/wsdl/">
   <types>

   <xsd:schema
   xmlns=http://www.w3.org/2001/XMLSchema
   targetNamespace=" databaseSearch ">
   <xsd:complexType name="SearchResult">
   <xsd:sequence>
   <xsd:element name="ResultsCount" type="xsd:int" />
   <xsd:element name="resultElements" type="typens:ResultElementArray"/>
   <xsd:element name="startIndex" type="xsd:int" />
   <xsd:element name="endIndex" type="xsd:int" />
   <xsd:element name="searchTime" type="xsd:double" />
   </xsd:sequence>
   </xsd:complexType>

   <xsd:complexType name="ResultElement">
   <xsd:sequence>
   <xsd:element name="Sourcename" type="xsd:string" />
   <xsd:element name="title" type="xsd:string" />
   <xsd:element name="URL" type="xsd:string" />
   <xsd:element name=" otherInfomation" type="xsd:string" />
   </xsd:sequence>
   </xsd:complexType>


   <xsd:complexType name="ResultElementArray">
   <xsd:complexContent>
   <xsd:restriction base="soapenc:Array">
   <xsd:attribute ref="soapenc:arrayType"
   wsdl:arrayType="typens:ResultElement[]" />
   </xsd:restriction>
   </xsd:complexContent>
   </xsd:complexType>
   </xsd:schema>
   </types>

   <message name="basicSearch">
   <part ref="basicQuery"/>


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   <part name="start" type="xsd:int" />
   <part name="maxResults" type="typens:intScope" />
   </message>

   <message name="advancedSearch">
   <part ref="advancedQuery"/>
   <part name=" dateStart " type="xsd:date" />
   <part name=" dateEnd" type="xsd:date" />
   <part name="start" type="xsd:int" />
   <part name="maxResults" type="typens:intScope" />
   <part name="order" type="xsd:string " />
   </message>

   <message name="fullSearch">
   <part ref="fullQuery"/>
   ......
   <part name="start" type="xsd:int" />
   <part name="maxResults" type="typens:intScope" />
   </message>

   <message name="searchResponse">
   <part name="return" type="typens:SearchResult" />
   </message>

   <portType name="SearchPort">
   <operation name="basicSearch">
   <input message="typens:basicSearch" />
   <output message="typens:searchResponse" />
   </operation>

   <operation name="advancedSearch">
   <input message="typens:advancedSearch" />
   <output message="typens:searchResponse" />
   </operation>

   <operation name="fullSearch">
   <input message="typens:fullSearch" />
   <output message="typens:searchResponse" />
   </operation>

   </portType>

   <binding name="SearchBinding" type="typens:SearchPort">
   <soap:binding style="rpc"
   transport="http://schemas.xmlsoap.org/soap/http" />
   <operation name="basicSearch">
   <soap:operation soapAction=" searchAction" />
   <input>



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   <soap:body use="encoded" namespace="databaseSearch"
   encodingStyle="http://schemas.xmlsoap.org/soap/encoding/" />
   </input>
   <output>
   <soap:body use="encoded" namespace="databaseSearch"
   encodingStyle="http://schemas.xmlsoap.org/soap/encoding/" />
   </output>

   <operation name="advancedSearch">
   <soap:operation soapAction="searchAction" />
   <input>
   <soap:body use="encoded" namespace="databaseSearch"
   encodingStyle="http://schemas.xmlsoap.org/soap/encoding/" />
   </input>
   <output>
   <soap:body use="encoded" namespace="databaseSearch"
   encodingStyle="http://schemas.xmlsoap.org/soap/encoding/" />
   </output>
   </operation>

   <operation name="fullSearch">
   <soap:operation soapAction=" searchAction" />
   <input>
   <soap:body use="encoded" namespace="databaseSearch"
   encodingStyle="http://schemas.xmlsoap.org/soap/encoding/" />
   </input>
   <output>
   <soap:body use="encoded" namespace="databaseSearch"
   encodingStyle="http://schemas.xmlsoap.org/soap/encoding/" />
   </output>
   </binding>
   <service name="SearchService">
   <port name="SearchPort" binding="typens:SearchBinding">
   <soap:address location=" " />
   </port>
   </service>
   </definitions>

3 The description of the search Webservice

   To describe the search Webservice, we refer to the UDDI [2] and UKOLN
   SCD [6] and define Search Webservice Description, Discovery and
   Integration (SDDI) in this part. SDDI will help the search system
   find and select the appropriate data sources.







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3.1 The XML schema of the SDDI

   We use the DC [3] standard to descript the character of the search
   Webservice. The other basic information for a web service is also
   added in the SDDI. All elements are divided into four groups.

   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.

   Source: Information about a second resource from which the present
   resource is derived.  While it is generally recommended that elements
   contain information about the present resource only, this element may
   contain metadata for the second resource when it is considered
   important for discovery of the present 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.

   Admin: The person or organization responsible for service operation
   and administration. Typically the value of Admin will be a name or
   name and email address.

   3 Instantiation

   Date A date of an event in the lifecycle of the resource

   Identifier  An unambiguous reference to the resource within a given
   context.


   Format Typically, Format may include the media-type or dimensions of
   the resource. Format may be used to identify the software, hardware,
   or other equipment needed to display or operate the resource.
   Examples of dimensions include size and duration. Recommended best
   practice is to select a value from a controlled vocabulary.


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   Type: The category of the resource, such as home page, novel, poem,
   working paper, technical report, essay, dictionary.  For the sake of
   interoperability, Type should be selected from an enumerated list
   that is currently under development in the workshop series.

   Categorybag: This is an optional list of name-value pairs that are
   used to tag a resource with specific taxonomy information. Some
   classification methods according to subjects can be adopted, such as
   (CLC) Chinese Library Classification  (LCC) Library of Congress
   Classification.


   4 Interface: the definition of program interface.

   AccessPolicy: A description of any constraints or legal prerequisites
   for accessing the collection or its component items.

   UDDI the UDDI content of this Webservice if available.

   accesspoint: URL of this Webservice

   queryschema: all supporting search parameters.

   The XML schema of SDDI is defined as follows.

   <xsd:element name = "SourceEntity">
   <xsd:complexType>
   <xsd:element ref= "Content" >
   <xsd:element ref= "Instantiation" >
   <xsd:element ref= "Copyright" >
   <xsd:element ref= "Interface" >
   </xsd:complexType>
   </xsd:element>


   The XML schema of element "Content":

   <xsd:element name= "Content" >
   <xsd:complexType>
   <xsd:element name = "Title" type="xsd:string"/ >
   <xsd:element name = "Description" type="xsd:string"/>
   <xsd:element name = "Language" type="xsd:language"
   maxOccurs="unbounded"/>
   <xsd:element name = "Source" type="xsd:string" minOccurs="0"
   maxOccurs="unbounded"/>
   </xsd:complexType>
   </xsd:element>



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   The XML schema of element "Copyright":

   <xsd:element name = "Copyright" >
   <xsd:complexType>
   <xsd:element name = "Creator" type="xsd:string" minOccurs="1"
   maxOccurs="unbounded"/>
   <xsd:element name = "Publisher" type="xsd:string" />
   <xsd:element name = "Rights" type="xsd:string"/>
   <xsd:element name = "Admin" type="xsd:string"/>
  </xsd:complexType>
   </xsd:element>

   The XML schema of element " Instantiation ":

   <xsd:element name = " Instantiation " >
   <xsd:complexType>
   <xsd:element name = "Date" type="xsd:date" />
   <xsd:element ref = " Identifier " type="xsd:string" minOccurs="0"
   maxOccurs="unbounded"/>
   <xsd:element ref = "Format" type="xsd:string" minOccurs="0"
   maxOccurs="unbounded"/>
   <xsd:element ref = "Type" type="xsd:string" minOccurs="0"
   maxOccurs="unbounded"/>
   <xsd:element ref = " Categorybag" type="xsd:string" minOccurs="0"
   maxOccurs="unbounded"/>
   </xsd:complexType>
   </xsd:element>

   <xsd:element name = "Categorybag" />
   <xsd:complexType>
   <xsd:attribute name= "keyName"/>
   <xsd:attribute name= "keyValue" use = "required"/>
   </xsd:complexType>

   The definition of "Identifier", "Format", "Type" is as same as that
   of "categorybag". They are all an optional list of name-value pairs.

   The XML schema of element "Interface":

   <xsd:element name = " Interface " >
   <xsd:complexType>
   <xsd:element name = " AccessPolicy" >
   <xsd:element ref = "UDDI" minOccurs="0" maxOccurs="1"/ >
   <xsd:element ref="Queryschema">
   <xsd:element name= "Accesspoint" type="xsd:anyURL" use="required"/>
   </xsd:complexType>

   <xsd:element ref=" Queryschema ">
   <xsd:complexType>


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   <xsd:sequence>
   <xsd:element ref = "Searchfield" minOccurs="1" maxOccurs=
   "unbounded"/>
   <xsd:element ref = "otherParameter" minOccurs="0" maxOccurs=
   "unbounded"/>
   </xsd:sequence>
   </xsd:complexType>

   "Searchfield" is all supported search field. We can use it to
   construct the "Fullquery" in query words. "otherParameter" defines
   the other parameter supported by function "Fullsearch"." Queryschema"
   is defined by resource provider.


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 to the SDDI.
   Meanwhile, the element can be complex element.

   1 find(element,value)

   Element:the name of element.
   Value: the value of element, which is xml format according to the
   different element of SDDI.

   This function returns the "accesspoint" according to the element and
   its value. For example:

   find(title, "ACM")

   This function will return the "acesspoint" of SDDI whose element
   "title" is "ACM".

   2 get(element1,value,element2)

   Return the value of element2 according to the value of element1.the
   format of results is accordance with XML. For example:

   Get((title, "ACM", character)


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   This function will return the element "character" of SDDI whose
   element "title" is "ACM".

4. Security Considerations

   Since the databases are always purchased by some organization, the IP
   access control will be used to protect the copyright.

   The organization will build their own search engine based on this
   protocol, so the Webservice and SDDI will not open to end user. The
   more additional security concerns should be decided by the
   corresponding organization.

5. Reference

5.1 Normative References
   [1] WSDL, http://www.w3.org/TR/wsdl12
   [2] UDDI, http://uddi.org/pubs/uddi_v3.htm
   [3] S. Weibel, J. Kunze, "Dublin Core Metadata for Resource
       Discovery", rfc2413, September 1998.

5.2 Informative References
   [4] Webservice , http://www.w3.org/2002/ws
   [5] The web service of Google, http://www.google.com/apis/
   [6] Simple Collection Description scheme,
   http://www.ukoln.ac.uk/metadata/cld/simple/



6. Author's Addresses

      Wang liang
      HUST
      WUHAN 430074
      P.R.China
      Phone: 86-27-87553494
      Email:wangliang_f@163.com


      Guo YiPing
      HUST
      WUHAN 430074
      P.R.China
      Email:gyp@hust.edu.cn


      Fang Ming
      HUST


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      WUHAN 430074
      P.R.China
      Email:fangming_w@263.net

Full Copyright Statement

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