Abstract:
To allow a user to use an appropriate search engine, this invention provides a computer system including: a client computer; a search engine; and a management computer, in which the management computer is configured to: collect logs of access; specify a parameter transferred from the client computer to an access destination of the client computer by analyzing the collected logs of access; judge that an access including a parameter judged as a search query is an access to the search engine; select a log of access to the search engine from the collected logs of access; extract an address of the search engine and the search query from the selected log of access to the search engine; and store a correspondence between the extracted address of the search engine and the extracted search query in a search engine profile.

Description:
CLAIM OF PRIORITY 
     The present application claims priority from Japanese patent application P2006-179519 filed on Jun. 29, 2006, the content of which is hereby incorporated by reference into this application. 
     BACKGROUND OF THE INVENTION 
     This invention relates to a meta-search technique with which a search engine is discriminately used according to a request of a user, and more particularly, to a technique of retrieving a search engine that meets a request of a user. 
     As a result of prevalence of personal computers and the Internet, an amount of electronic documents that can be accessed by a user is increasing. As a countermeasure for such situation, there is known a document search technique. The document search technique is a technique of retrieving a document that matches a search query input by the user. It should be noted that the search query may be a keyword or a sentence. 
     A large number of search engines have been constructed on intranets of companies and the like, and on the Internet. The user uses those search engines to acquire an appropriate document. It should be noted that the search engines are classified into a general-purpose search engine, that is the horizontal search engine, and a dedicated-purpose search engine, that is the vertical search engine. 
     The general-purpose search engine searches large variety of document stored in the search engine. An example of the general-purpose search engine is Google™. 
     The vertical search engine retrieves the document requested by the user from among the specific types of documents. Examples of the vertical search engine include a patent search engine, a search engine for in-company reports, and a manual search engine. 
     The user needs to discriminately use an appropriate search engine to acquire an appropriate document. However, it is extremely complicated for the user to discriminately use the search engine according to a purpose of the search. 
     JP 2002-278980 A discloses a meta-search technique that solves the problem described above. The meta-search technique is a technique of integrally performing search processing with respect to a plurality of search engines. The specific processing is as follows. First, a search query is input to a meta-search engine. Then, the meta-search engine transmits a search request to the plurality of search engines in parallel. After that, the meta-search engine collectively outputs search results received from the respective search engines. As described above, the meta-search technique improves convenience of the user. 
     On the other hand, a quality of the search result is important for improving the convenience of the user. JP 2005-242760 A discloses a technique for improving a search quality. In the technique disclosed in JP 2005-242760 A, a search know-how of other users is used. Specifically, judgment is made on a value of a document corresponding to a search result, based on an operation of the user with respect to the search result. 
     Alternatively, “Information Retrieval Algorithm” by Kenji Kita, Kazuhiko Tsuda, and Masami Shishibori, KYORITSU SHUPPAN CO., LTD discloses various techniques for retrieving a document, such as a search using a Boolean expression, which includes an OR search, and a similarity search using a vector model. 
     SUMMARY OF THE INVENTION 
     The conventional meta-search techniques are provided under a presupposition that the search engines are known. Thus, a list of the known search engines needs to be managed. However, it is extremely difficult to manage the list of search engines. Therefore, the meta-search techniques require a high cost. 
     Further, the meta-search engine needs to transmit a search query in a format conforming to the respective search engines. Thus, the format that conforms to the respective search engines needs to be managed as additional information in the list of search engines. Accordingly, the cost required for managing the list of search engines further increases. 
     This invention has been made in view of the above-mentioned problems, and it is therefore an object of this invention to provide a technique for supporting a user in discriminately using a search engine. 
     According to an exemplary embodiment of this invention, there is provided a computer system, comprising: at least one client computer including a processor, a memory, and an interface; at least one search engine; and a management computer, and the client computer, search engine, and the management computer are connected via a network; wherein the management computer is configured to: collect logs of access from the client computer; specify a parameter transferred from the client computer to an access destination of the client computer by analyzing the collected logs of access; judge whether the specified parameter is a search query; judge that an access including the parameter judged as the search query is an access to the search engine; select a log of access to the search engine from the collected logs of access; extract an address of the search engine and the search query from the selected log of access to the search engine; and store a correspondence between the extracted address of the search engine and the extracted search query in a search engine profile. 
     According to a representative embodiment of this invention, the user can use an appropriate search engine depending on its purpose. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The present invention can be appreciated by the description which follows in conjunction with the following figures, wherein: 
         FIG. 1  is a block diagram of a configuration of a computer system according to a embodiment of this invention; 
         FIG. 2  is an explanatory diagram of a access log stored in a meta-search server according to the embodiment of this invention; 
         FIG. 3  is a configuration diagram of a search engine profile stored in the meta-search server according to the embodiment of this invention; 
         FIG. 4  is an explanatory diagram of syntax of a URL in the CGI specification according to the embodiment of this invention; 
         FIG. 5  is a configuration diagram of a search engine attribute file stored in the meta-search server according to the embodiment of this invention; 
         FIG. 6  is a flowchart of information update processing executed by the meta-search server according to the embodiment of this invention; 
         FIG. 7  is a flowchart of a query term list creation processing executed by the meta-search server according to the embodiment of this invention; 
         FIG. 8  is an explanatory diagram of a search site screen displayed on a client computer according to the embodiment of this invention; 
         FIG. 9  is an explanatory diagram of a HTML document transmitted from the search engine according to the embodiment of this invention; 
         FIG. 10  is a flowchart of meta-search processing executed by the meta-search server according to the embodiment of this invention; and 
         FIG. 11  is an explanatory diagram of a search result screen displayed on the client computer according to the embodiment of this invention. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     Hereinafter, an embodiment of this invention will be described with reference to the drawings. 
       FIG. 1  is a block diagram of a configuration of a computer system according to the embodiment of this invention. 
     The computer system includes one or more client computers  201 , a meta-search server  100 , a plurality of search engines  301 , a network  400 , and a network  500 . 
     The network  400  connects the client computers  201  with the meta-search server  100 . The network  400  is, for example, a local area network (LAN). 
     Further, the network  500  connects the meta-search server  100  with the search engines  301 . The network  500  is, for example, the Internet. It should be noted that the networks  400  and  500  may constitute a single network. 
     Each of the client computers  201  includes a CPU, a main memory, and an interface. The CPU provided in the client computer  201  executes a program stored in the main memory to perform various types of processing. The main memory provided in the client computer  201  stores the program executed by the CPU, information required by the CPU, and the like. The interface provided in the client computer  201  is connected to the meta-search server  100  via the network  400 . 
     The client computer  201  transmits a search query to the search engines  301 . After that, the client computer  201  receives search results from the search engines  301 . 
     Each of the search engines  301  includes a CPU, a main memory, and an interface. The CPU provided in the search engine  301  executes a program stored in the main memory to perform various types of processing. The main memory provided in the search engine  301  stores the program executed by the CPU, information required by the CPU, and the like. For example, the main memory provided in the search engine  301  stores a common gateway interface (CGI) program. The interface provided in the search engine  301  is connected to the meta-search server  100  via the network  500 . 
     The search engine  301  receives a search query from the client computer  201 . Next, the search engine  301  searches for a site that matches the received search query. Then, the search engine  301  transmits to the client computer  201  information on the searched site as the search result. In other words, the search engine  301  serves as a database for searching for a site required by the client computer  201 . 
     The meta-search server  100  includes a CPU  101 , a main memory  102 , an I/O device  103 , a network device  104 , and a disk device  110 . Further, the meta-search server  100  is equipped with a function similar to that of a general proxy server. The proxy server is a computer that permits web access of the client computer  201  based on user authentication. 
     The CPU  101  executes a program stored in the main memory  102  to perform various types of processing. Specifically, the CPU  101  loads and executes a program stored in the disk device  110  in the main memory  102 . 
     The main memory  102  stores the program executed by the CPU  101 , information required by the CPU  101 , and the like. A user inputs information to the I/O device  103 . In addition, the I/O device  103  outputs information in response to an instruction of the CPU  101 . For example, the I/O device  103  includes at least one of a keyboard, a mouse, and a display. 
     The network device  104  is connected to the client computer  201  via the network  400 . Further, the network device  104  is connected to the search engine  301  via the network  500 . 
     The disk device  110  stores various types of information. Specifically, the disk device  110  stores an OS  111 , an access log collecting program  112 , an access log analyzing program  113 , an access log  114 , a search engine profile  115 , and a search engine attribute file  116 . 
     The OS  111  controls overall processing performed by the meta-search server  100 . 
     The access log collecting program  112  collects logs of access to a search engine or other web page via network  500  from the client computer  201 . The access log collecting program  112  manages the collected logs as the access log  114 . It should be noted that the access log collecting program  112  may use an log file of the proxy server as the access logs of the client computer  201 . 
     The access log analyzing program  113  analyzes the access log  114 . Accordingly, the access log analyzing program  113  updates the search engine profile  115  and the search engine attribute file  116 . 
     The access log  114  includes logs of access from the client computer  201 , which have been collected by the access log collecting program  112 . It should be noted that the access log  114  will be described later in detail with reference to  FIG. 2 . 
     The search engine profile  115  manages a correspondence between the search engine  301  and a term transmitted as the search query to the search engine  301 . It should be noted that the search engine profile  115  will be described later in detail with reference to  FIG. 3 . 
     The search engine attribute file  116  manages attribute information of the search engine  301 . It should be noted that the search engine attribute file  116  will be described later in detail with reference to  FIG. 5 . 
     The meta-search server  100  may be realized by a plurality of servers. For example, the meta-search server  100  may be realized by a server that executes the access log collecting program  112  and a server that executes the access log analyzing program  113 . 
       FIG. 2  is an explanatory diagram of the access log  114  stored in the meta-search server  100  according to the embodiment of this invention. 
     The access log  114  includes a command type  1141 , an access destination uniform resource locator (URL)  1142 , and a user ID  1143 . 
     The command type  1141  is a type of a command transmitted from the client computer  201 . It should be noted that in this embodiment, the client computer  201  transmits a command according to a hypertext transfer protocol (HTTP). However, the client computer  201  may transmit a command according to other protocols. 
     The access destination URL  1142  is an address of a site accessed according to the command. 
     Information is registered as “http://&lt;host&gt;:&lt;port&gt;/&lt;path&gt;?&lt;searchpart&gt;” in the access destination URL  1142 . The “host” indicates a domain name of a network host or an IP address thereof. The “port” indicates a port number used for connection. It should be noted that when the “port” is omitted, a default value “80” is used as the “port”. The “path” indicates a path for specifying a location of a resource to be accessed. The “searchpart” indicates a query character string which is passed to an http server as an argument. The search query with respect to the search engine is embedded in the “searchpart”. 
     The user ID  1143  is an identifier unique to the client computer  201  as a transmission source of the command. 
       FIG. 3  is a configuration diagram of the search engine profile  115  stored in the meta-search server  100  according to the embodiment of this invention. 
     The search engine profile  115  includes a URL  1151 , a name  1152 , and a characteristic word list  1153 . 
     The URL  1151  is an address of a site judged as being the search engine  301  by the meta-search server  100 . It should be noted that the meta-search server  100  automatically judges, based on access from the client computer  201 , whether a site of the access destination is the search engine  301 . 
     The name  1152  is information used by the search engine  301  corresponding to the URL  1151  of the record, for specifying a search query from the search command. Transmission of the search command is a type of access from the client computer  201  to the search engine  301 , and the search command contains a URL of a CGI specification to be described later with reference to  FIG. 4 . 
     The characteristic word list  1153  includes a characteristic word and the number of search times. The characteristic word is a term transmitted as the search query to the search engine  301  corresponding to the URL  1151  of the record. The number of search times is the number of times the characteristic word has been transmitted to the search engine  301  corresponding to the URL  1151  of the record. 
       FIG. 4  is an explanatory diagram of the URL of the CGI specification according to the embodiment of this invention. 
     The CGI is a specification on how general programs can be run on the web server in response to a web request (including setting of an environment variable (meta-variable) name and value). 
     Information in a format unique to the CGI is included in the URL as the “searchpart”. Specifically, one or more pairs of a name and value are included in the URL as the “searchpart”. In the case where a plurality of pairs of the name and value are included, the pairs are coupled to each other by a symbol “&amp;”. Further, in each of the pairs, the name and the value are coupled to each other by a symbol “=”. In other words, a pair of an i-th name and a value corresponding to the name is described as “name i=value i”. 
     A CGI program of the search engine  301  acquires a character string corresponding to the “searchpart” according to an environment variable QUERY_STRING, for example. Next, the CGI program of the search engine  301  reads the acquired character string according to the CGI format. Accordingly, the CGI program of the search engine  301  extracts the pair of the name and value from the acquired character string. 
     With what kind of character string the name to be stored as the “searchpart” is to be described is not particularly specified in the CGI. In actuality, a name to be used in transmitting a search query input by the user to the CGI program is set in advance in the client computer  201  and the search engine  301 . In other words, the set name indicates that the value in pair with the name is the search query. 
     The client computer  201  converts the search query input by the user into a value. Next, the client computer  201  stores the converted value and the name set in advance in a pair in the URL as the “searchpart”. Then, the client computer  201  transmits the URL to the search engine  301 . 
     The search engine  301  extracts a value in pair with the name set in advance from the received URL. Then, the search engine  301  determines that the extracted value is the search query. 
     As described above, a name for specifying the search query is set in advance in the client computer  201  and the search engine  301 . Thus, the search engine  301  can read information in the CGI format. 
     It should be noted that a pair of a name and value that do not indicate the search query may be included as the “searchpart” in the URL transmitted to the search engine  301 . At this time, which name indicates the search query depends on a design of an HTML document, for inputting the search query to the search engine  301 . 
     Here, an effect of this embodiment will be described. The conventional meta-search server cannot grasp which name indicates the search query. Therefore, the conventional meta-search server cannot specify which part of the URL indicates the search query. 
     However, the meta-search server  100  of this embodiment can extract a search query from the URL transmitted to an arbitrary search engine  301 . Details of this processing will be described later. 
       FIG. 5  is a configuration diagram of the search engine attribute file  116  stored in the meta-search server  100  according to the embodiment of this invention. 
     The search engine attribute file  116  includes a URL  1161 , a title  1162 , a termhood  1163 , and an access frequency  1164 . 
     The URL  1161  is an address of a site judged as being the search engine  301  by the meta-search server  100 . The title  1162  is a character string in a TITLE tag contained in the HTML document which is acquired by accessing the URL  1161  of the record. 
     The termhood  1163  indicates a degree of technicality of the search engine  301  corresponding to the URL  1151  of the record. The termhood  1163  is a ratio of the number of kinds of terms to a total number of terms. The total number of terms is the number of terms that have been transmitted as the search query to the search engine  301 . The number of kinds is the number of different terms among the terms transmitted as the search query to the search engine  301 . 
     The closer the termhood  1163  is to “0”, the higher the technicality of the search engine  301 . This is because, since terms regarding a field of expertise conforming to the search engine  301  is input to the search engine  301  having high technicality, the possibility of the same term being input is high. On the other hand, the technicality of the search engine  301  becomes lower as the termhood  1163  becomes closer to “1”, which means that the search engine is a general search engine  301 . This is because, since terms regarding various fields are input to the general search engine  301 , the possibility of the same term being input is low. 
     The access frequency  1164  is the number of times the search engine  301  corresponding to the URL  1161  of the record has been accessed. 
       FIG. 6  is a flowchart of information update processing executed by the meta-search server  100  according to the embodiment of this invention. 
     The information update processing is executed periodically, for example. 
     First, the meta-search server  100  executes query term list creation processing (S 11 ). It should be noted that the query term list creation processing will be described later in detail with reference to  FIG. 8 . By this processing, the meta-search server  100  creates a query term list for each search engine  301 . 
     Subsequently, the meta-search server  100  updates the search engine profile  115  based on the created query term list (S 12 ). 
     Specifically, the meta-search server  100  selects from the search engine profile  115  a record whose URL  1151  of the search engine profile  115  matches the URL of the search engine  301  corresponding to the created query term list. Next, the meta-search server  100  sequentially selects the terms contained in the query term list. Then, the meta-search server  100  selects from the selected record, a column whose characteristic word contained in the characteristic word list  1153  of the search engine profile  115  matches the selected term. Next, the meta-search server  100  increments the number of search times of the selected column. 
     It should be noted that the meta-search server  100  adds a new column to the characteristic word list  1153  of the selected record when being unable to select a column. Subsequently, the meta-search server  100  stores the selected term as the characteristic word of the added column. Further, the meta-search server  100  stores “1” as the number of search times of the added column. 
     In addition, the meta-search server  100  adds a new record to the search engine profile  115  when being unable to select a record that matches the URL. Next, the meta-search server  100  stores a URL of the search engine  301  corresponding to the created query term list as the URL  1151  of the newly added column. Then, the meta-search server  100  stores a name specified as being indicative of a search query in the query term list creation processing in Step S 11 , the processing of which is shown in  FIG. 7 , as the name  1152  of the new record. After that, the meta-search server  100  stores all the terms contained in the query term list as the characteristic word list  1153  of the new record. 
     As described above, the meta-search server  100  updates the search engine profile  115 . 
     Next, the meta-search server  100  updates the search engine attribute file  116  (S 13 ). 
     Specifically, the meta-search server  100  adds a new record to the search engine attribute file  116 . Subsequently, the meta-search server  100  stores a URL of a site judged as being the search engine  301  in Step S 115  to be described later as the URL  1161  of the new record. 
     Then, the meta-search server  100  acquires an HTML document by accessing the stored URL. After that, the meta-search server  100  extracts a character string from the TITLE tag of the acquired HTML document. Then, the meta-search server  100  stores the extracted character string as the title  1162  of the new record. 
     Subsequently, the meta-search server  100  stores a difference ratio calculated in Step S 115  to be described later as the termhood  1163  of the new record. Next, the meta-search server  100  stores the total number calculated in Step S 114  to be described later as the access frequency  1164  of the new record. 
     As described above, the meta-search server  100  updates the search engine attribute file  116 . 
     Then, the meta-search server  100  ends the information update processing. 
       FIG. 7  is a flowchart of the query term list creation processing executed by the meta-search server  100  according to the embodiment of this invention. 
     It should be noted that the query term list creation processing is executed in Step S 11  of the information update processing. 
     First, the meta-search server  100  classifies the access destination URLs  1142  of the access log  114  for each site of the access destination (S 111 ). 
     For example, the processing is carried out by a method as described below. The meta-search server  100  extracts a character string from the head of the URL to immediately before the symbol “?” from the access destination URL  1142  of the access log  114 . Next, the meta-search server  100  removes the head part “http://” from the extracted character string. Then, the meta-search server  100  removes the character string from the symbol “:” to immediately before the symbol “/” from the removed character string. Accordingly, the meta-search server  100  acquires from the extracted character string a character string corresponding to the “host”+“path” of the URL. 
     Then, the meta-search server  100  classifies the access destination URLs  1142  of the access log  114  for each site of the access destination based on the character string corresponding to the “host”+“path” of the URL. In other words, when the character string corresponding to the “host”+“path” of the URL is the same as the removed character string, the meta-search server  100  judges the log as being an access log for the same site. 
     Next, the meta-search server  100  judges whether processing from Steps S 113  to S 116  has been executed with respect to all the classified access destination URLs  1142  (S 112 ). When processing is executed on all the access destination URLs  1142 , the meta-search server  100  ends the query term list creation processing. 
     On the other hand, when any of the access destination URLs  1142  is not processed, the meta-search server  100  selects one of the sites of the access destination which has not been selected in the previous Step S 113 . Then, the meta-search server  100  extracts all the pairs of the name and value from all the URLs  1142  classified as the selected site (S 113 ). 
     Next, the meta-search server  100  extracts the name and value from all the extracted pairs according to a construction of the CGI format. Specifically, the meta-search server  100  specifies a break between the pairs by the symbol “&amp;”. Further, the meta-search server  100  specifies a break between the name and the value by the symbol “=”. Accordingly, the meta-search server  100  can extract the name and value from all the extracted pairs. 
     It should be noted that even when the format is that other than the CGI format, the meta-search server  100  can extract the name and value according to a construction thereof. This is because a construction resides in other formats than the CGI format as well. 
     Next, the meta-search server  100  classifies the extracted values for each of the extracted names. Then, the meta-search server  100  calculates the total number and the number of kinds of the classified values (S 114 ). The total number is the number of values classified for each name by the meta-search server  100 . The number of kinds is the number of different values that do not overlap one another among the values classified for each name by the meta-search server  100 . 
     Next, the meta-search server  100  judges whether the access destination site selected in Step S 113  is the search engine  301  based on the calculated total number and number of kinds (S 115 ). 
     Specifically, the meta-search server  100  divides the calculated number of kinds by the calculated total number to obtain a difference ratio. Then, the meta-search server  100  compares the obtained difference ratio with a preset threshold. When the obtained difference ratio is equal to or larger than the threshold, the meta-search server  100  judges that the access destination site selected in Step S 113  is the search engine  301 . This is because, since various terms are transmitted to the search engine  301  as the search query, the difference ratio increases. At this time, the meta-search server  100  specifies the names to be used for specifying the search query from the names extracted in Step S 113 . 
     Next, the meta-search server  100  extracts all the values that are in pair with the names to be used for specifying the search query from the values extracted in Step S 113 . Then, the meta-search server  100  decodes the extracted values to acquire the terms input as the search query. It should be noted that when the term input as the search query is in Japanese, the argument part of the CGI has been encoded based on a hexadecimal system. Subsequently, the meta-search server  100  stores all the acquired terms in the query term list (S 116 ). 
     Next, the meta-search server  100  returns to Step S 112 . Then, the meta-search server  100  repeats the query term list creation processing until all the access destination URLs  1142  of the access log  114  are processed. 
     On the other hand, when the obtained difference ratio is smaller than the threshold, the meta-search server  100  judges that the access destination site selected in Step S 113  is not the search engine  301 . Thus, the meta-search server  100  does not need to create the query term list. Therefore, the meta-search server  100  directly returns to Step S 112 . Then, the meta-search server  100  repeats the query term list creation processing until all the access destination URLs  1142  of the access log  114  are processed. 
     As described above, the meta-search server  100  specifies only the access to the search engine  301  from the access logs. Next, the meta-search server  100  extracts the term transmitted to the search engine  301  as the search query from the specified access. Then, the meta-search server  100  stores the extracted term in the list to create the query term list. 
     It should be noted that the meta-search server  100  has judged whether the access destination site is the search engine  301  based on the total number and the number of kinds in Step S 115 . However, the meta-search server  100  may judge whether the access destination site is the search engine  301  by other methods. 
     For example, when the client computer  201  is operated by a user using Japanese, there is a high possibility that the search query is a Japanese term. Thus, the meta-search server  100  specifies a name that is often in pair with a value corresponding to a Japanese character string as the name to be used for specifying the search query. Further, the meta-search server  100  judges a frequently accessed site, a URL of which includes the value corresponding to the Japanese character string, as being the search engine  301 . 
     In addition, the meta-search server  100  may judge whether the access destination site is the search engine  301  based on information included in the HTML document. Specifically, the meta-search server  100  acquires an HTML document by accessing a URL of the access destination site. Subsequently, the meta-search server  100  judges whether information unique to the search engine  301  is included in the acquired HTML document. The information unique to the search engine  301  includes a text area for input of the search query and a transmission button for transmitting the search query. 
     When the information unique to the search engine  301  is included in the HTML document, the meta-search server  100  judges the access destination site as being the search engine  301 . 
       FIG. 8  is an explanatory diagram of a search site screen displayed on the client computer  201  according to the embodiment of this invention. 
     The search site screen displays an HTML document transmitted from the search engine  301  using a web browser equipped in the client computer  201 . 
     The search site screen includes a text area for input of the search query and a search button for requesting transmission of the search query. 
       FIG. 9  is an explanatory diagram of the HTML document transmitted from the search engine  301  according to the embodiment of this invention. 
     The HTML document of this explanatory diagram is transmitted for displaying the search site screen shown in  FIG. 8 . 
     The HTML document for displaying the search site screen includes a “FORM” tag and an “input” tag. The “FORM” tag is a tag for creating an input form. The “input” tag is used as a part of the form. It should be noted that a “TEXTAREA” tag or the like may be used instead of the “input” tag. 
     The HTML document for displaying the search site screen includes character strings related to the search, such as a “keyword”, “retrieve”, and “search”. Those character strings are displayed so that the user recognizes the search site. 
     In other words, the meta-search server  100  can judge whether the access destination site is the search engine  301  based on whether the HTML document includes the “FORM” tag, the “input” tag, the character strings related to the search, and the like. 
       FIG. 10  is a flowchart of search engine search processing executed by the meta-search server  100  according to the embodiment of this invention. 
     Here, descriptions will be made of a case where the search engine  301  is retrieved through the AND search. However, this invention can be applied to any technique for retrieving a document, such as a search using a Boolean expression, which includes an OR search, and a similarity search using a vector model. Those search techniques are disclosed in “Information Retrieval Algorithm” by Kenji Kita, Kazuhiko Tsuda, and Masami Shishibori, KYORITSU SHUPPAN CO., LTD. 
     The client computer  201  transmits a search request of the search engine to the meta-search server  100 . It should be noted that the search request of the search engine includes one or more terms to be the search query. 
     The meta-search server  100  receives the search request of the search engine from the client computer  201 . Next, the meta-search server  100  extracts a term to be the search query one at a time from the received search request (S 21 ). 
     Then, the meta-search server  100  selects from the search engine profile  115  all the records whose characteristic word contained in the characteristic word list  1153  of the search engine profile  115  matches the extracted term. Next, the meta-search server  100  extracts the URL  1151  from the selected record (S 22 ). 
     Subsequently, the meta-search server  100  judges whether all the terms contained in the received search request have been extracted in Step S 21  (S 23 ). When not all the terms contained in the search request have been extracted, the meta-search server  100  returns to Step S 21  and repeats the processing with respect to the term not yet extracted. 
     On the other hand, when all the terms contained in the search request have been extracted, the meta-search server  100  specifies the extracted URL  1151  even in the processing for any of the terms extracted in Step S 21  (S 24 ). 
     Next, the meta-search server  100  transmits to the client computer  201  the specified URL  1151  as a result for the search engine search request (S 25 ). For example, the meta-search server  100  creates a search result screen including the search result. Then, the meta-search server  100  transmits the created search result screen to the client computer  201 . 
     The client computer  201  receives the search result screen from the meta-search server  100 . Next, the client computer  201  displays the received search result screen. The user can select an appropriate search engine  301  by referring to the displayed search result screen. 
       FIG. 11  is an explanatory diagram of the search result screen displayed on the client computer  201  according to the embodiment of this invention. 
     A URL, a title, a representative keyword, a termhood, and an access frequency are displayed on the search result screen as the search result. 
     The URL is an address of the search engine  301  that satisfies a condition requested by the client computer  201 . 
     The title is a name that indicates characteristics of the search engine  301  corresponding to the URL of the record. The representative keyword is a representative term transmitted to the search engine  301  corresponding to the URL of the record. 
     The termhood indicates a degree of technicality of a document that can be searched for by the search engine  301  corresponding to the URL of the record. The access frequency is the number of times the search engine  301  corresponding to the URL of the record has been accessed. 
     By providing the title, the termhood, and the access frequency in the search result screen, the user can select an appropriate search engine. In addition, by providing the representative keyword in the search result screen, the user can judge whether the search engine matches the request. 
     Next, a description will be given of search result screen creation processing executed by the meta-search server  100 . 
     First, the meta-search server  100  stores the URL specified in Step S 24  in the search engine search processing of  FIG. 10 , as the URL of the search result screen. Next, the meta-search server  100  selects a record whose URL  1161  of the search engine attribute file  116  matches the URL specified in Step S 24  in the search engine search processing of  FIG. 10 . 
     Then, the meta-search server  100  extracts the title  1162 , the termhood  1163 , and the access frequency  1164  from the selected record. After that, the meta-search server  100  stores the extracted title  1162  as the title of the search result screen. Subsequently, the meta-search server  100  stores the extracted termhood  1163  as the technicality of the search result screen. Then, the meta-search server  100  stores the extracted access frequency  1164  as the access frequency of the search result screen. 
     Next, the meta-search server  100  selects from the search engine profile  115  a record whose URL  1151  of the search engine profile  115  matches the URL specified in Step S 24  in the search engine search processing of  FIG. 10 . Then, the meta-search server  100  extracts a characteristic word that has frequently been searched for from the characteristic word list  1153  of the selected record. After that, the meta-search server  100  stores the extracted characteristic word as the representative keyword of the search result screen. 
     As described above, the meta-search server  100  creates the search result screen. 
     While the present invention has been described in detail and pictorially in the accompanying drawings, the present invention is not limited to such detail but covers various obvious modifications and equivalent arrangements, which fall within the purview of the appended claims.