Abstract:
A computer implemented method including: periodically requesting an off-line data update processing based on automatic determination of a degree of importance of data and an update frequency; and updating the off-line data based on the requesting and displaying a page of on-line data resulting from the updating.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application is based upon and claims the benefit of priority of the prior Japanese Patent Application No. 2008-300852, filed on Nov. 26, 2008, the entire contents of which are incorporated herein by reference. 
     FIELD 
     The embodiments discussed herein relate to a relay server, mobile terminal, information browsing system and a method thereof for handling information to be updated. 
     BACKGROUND 
     In recent years, there are an increasing number of mobile terminals such as mobile phones and PDA&#39;s (personal digital assistant) provided with a full browser. Accordingly, access to contents for PC&#39;s on a Web server as an information delivery server is expanding. 
     However, mobile terminals are often connected to a network through wireless communication and are generally more frequently disconnected than PC&#39;s connected to a network through wired communication. 
     Therefore, Japanese Patent Laid-Open No. 2005-316523 discusses a mobile terminal capable of browsing a content on a Web server off-line even if the connection to the network is interrupted. The technique capable of browsing a content on a Web server off-line even if the connection to the network is interrupted transfers the content on the Web server to the inside of a mobile terminal so that the content can be browsed even if the connection to the network is interrupted. However, the user of the mobile terminal needs to explicitly transfer the content on the Web server. Furthermore, even when the content on the Web server is updated, the user of the mobile terminal needs to explicitly transfer the content from the Web server to the mobile terminal again. 
     Japanese Patent Laid-Open No. 2002-149540 discusses a technique whereby a gate way (GW) server located between a mobile terminal and a Web server checks updates of a content on the Web server side and reports every update of the content to the mobile terminal. According to the technique, updates of the content on the Web server are checked page by page. However, such a page-by-page update check on the content on the Web server regards a change of an access counter whose contents are changed with every access or a change in an advertisement portion as an update. 
     A “hatena antenna” discusses a function that allows the user to set regions to be checked for updates and regions whose update checks are to be ignored. However, it is difficult to meticulously set regions to be checked for updates and regions whose update checks are to be ignored using a limited input interface of the mobile terminal. 
     SUMMARY 
     According to an aspect of an embodiment, a computer implemented method includes periodically requesting an off-line data update processing based on automatic determination of a degree of importance of data and an update frequency, and updating the off-line data based on the requesting and displaying a page of on-line data resulting from the updating. 
     The object and advantages of the invention will be realized and attained by means of the elements and combinations particularly pointed out in the claims. 
     It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory and are not restrictive of the invention, as claimed. 
    
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         FIG. 1  is a configuration diagram illustrating an example of an information browsing system according to an embodiment; 
         FIG. 2  is a hardware configuration diagram illustrating an example of a computer system; 
         FIG. 3  is a block configuration diagram illustrating an example of a mobile terminal; 
         FIG. 4  is a block configuration diagram illustrating an example of a GW server; 
         FIGS. 5A and 5B  are sequence diagrams illustrating an example of off-line data update processing carried out by the GW server; 
         FIG. 6  is a configuration diagram illustrating an example of an update schedule DB; 
         FIG. 7  is a configuration diagram illustrating an example of an HTML cache; 
         FIG. 8  is a configuration diagram illustrating an example of an update frequency DB; 
         FIG. 9  is a configuration diagram illustrating an example of an off-line data DB; 
         FIG. 10  is a configuration diagram illustrating an example of an in-page degree of importance DB; 
         FIG. 11  is a sequence diagram illustrating an example of off-line data referencing processing carried out by the mobile terminal; 
         FIG. 12  is a configuration diagram illustrating an example of a region display time DB; 
         FIGS. 13A and 13B  are sequence diagrams illustrating an example of processing at the time of off-line data update of the mobile terminal; 
         FIG. 14  is a configuration diagram illustrating an example of a reloading count DB; 
         FIG. 15  is a configuration diagram illustrating an example of the off-line data DB; 
         FIG. 16  illustrates a first method of target region determination performed by a display region acquisition section; 
         FIG. 17  illustrates a second method of target region determination performed by the display region acquisition section; 
         FIG. 18  illustrates a third method of target region determination performed by the display region acquisition section; 
         FIG. 19  illustrates fourth and fifth methods of target region determination performed by the display region acquisition section; 
         FIG. 20  is a flowchart illustrating a procedure for update frequency discrimination processing performed by an update frequency discrimination section; 
         FIG. 21  illustrates an example of a method of averaging a time during which the user uses the mobile terminal; and 
         FIG. 22  is a flowchart illustrating another procedure for update frequency discrimination processing performed by the update frequency discrimination section. 
     
    
    
     DESCRIPTION OF EMBODIMENTS 
     Hereinafter, embodiments will be explained with reference to the accompanying drawings. A Web server will be explained according to an embodiment as an example of an information delivery server, but the information delivery server may be any server or apparatus that provides information to be updated. Moreover, a GW server will be explained an example of a relay server, but the relay server may be any terminal or apparatus that provides information delivered from the information delivery server as off-line data to a mobile terminal. 
       FIG. 1  is a configuration diagram illustrating an example of an information browsing system according to an embodiment. The information browsing system  1  in  FIG. 1  includes a mobile terminal  10 , a GW server  11 , a Web server  12 , a wireless communication network  13  and a wired communication network  14 . 
     The GW server  11  is connected to at least one mobile terminal  10  via the wireless communication network  13  such as a wireless LAN. The GW server  11  is connected to at least one Web server  12  via the wired communication network  14  such as the Internet. The GW server  11  connects the wireless communication network  13  and the wired communication network  14 , which are different networks. 
     The mobile terminal  10 , GW server  11  and Web server  12  in  FIG. 1  may be realized by a computer system in a hardware configuration as illustrated in  FIG. 2 , for example. 
       FIG. 2  is a hardware configuration diagram illustrating an example of a computer system. The computer system in  FIG. 2  includes an input apparatus  21 , an output apparatus  22 , a drive apparatus  23 , an auxiliary storage apparatus  24 , a main storage apparatus  25 , a processing unit  26  and an interface apparatus  27  interconnected with each other via a bus. 
     The input apparatus  21  includes a keyboard and mouse or the like and inputs various signals. The output apparatus  22  includes a display apparatus or the like and displays various windows and data or the like. The interface apparatus  27  includes a modem, wired/wireless LAN card or the like and is used to make connections with the wireless communication network  13  and wired communication network  14 . 
     A program for causing the computer system in  FIG. 2  to function as the mobile terminal  10 , GW server  11  or Web server  12  is delivered through distribution of a computer readable recording or storage medium  28  or delivered through downloading or the like from the wireless communication network  13  or the wired communication network  14 . For the recording medium  28  that records the program, a recording medium that optically, electrically or magnetically records information onto a CD-ROM, flexible disk or magneto-optical disk or a semiconductor memory that electrically records information such as a ROM and flash memory may be used. 
     When the recording medium  28  in which the program is recorded is set in the drive apparatus  23 , the program is installed from the recording medium  28  into the auxiliary storage apparatus  24  via the drive apparatus  23 . A program downloaded from the wireless communication network  13  or wired communication network  14  is installed into the auxiliary storage apparatus  24  via the interface apparatus  27 . 
     The auxiliary storage apparatus  24  stores the installed program and also stores necessary files and data or the like. The main storage apparatus  25  reads a necessary program from the auxiliary storage apparatus  24  at startup of the computer and stores the program. The processing unit  26  realizes various types of processing, which is described in detail below, according to the program stored in the main storage apparatus  25 . 
       FIG. 3  is a block configuration diagram illustrating an example of a mobile terminal. The mobile terminal  10  in  FIG. 3  includes a Web browser  31 , a local proxy  32 , a freshness determining section  33 , a communication section  34 , an on-line switching processing section  35 , an off-line data updating section  36 , a reloading operation recording section  37 , a region display time DB  38 , an off-line data DB  39  and a reloading count DB  40 . The Web browser  31  includes a display region acquisition section  41 . 
     The Web browser  31 , local proxy  32 , freshness determining section  33 , communication section  34 , on-line switching processing section  35 , off-line data updating section  36 , reloading operation recording section  37 , region display time DB  38 , off-line data DB  39  and reloading count DB  40  are realized by, for example, the processing unit  26  ( FIG. 2 ) executing the program. 
     Details of the Web browser  31 , local proxy  32 , freshness determining section  33 , communication section  34 , on-line switching processing section  35 , off-line data updating section  36 , reloading operation recording section  37 , region display time DB  38 , off-line data DB  39  and reloading count DB  40  are described in detail below. 
       FIG. 4  is a block configuration diagram illustrating an example of a GW server. The GW server  11  in  FIG. 4  includes a service data acquisition section  51 , an update frequency discrimination section  52 , a communication section  53 , an off-line data updating section  54 , an off-line data transfer section  55 , an update schedule management section  56 , an off-line data DB  57 , an in-page degree of importance DB  58 , an HTML cache  59 , an update schedule DB  60  and an update frequency DB  61 . 
     The service data acquisition section  51 , update frequency discrimination section  52 , communication section  53 , off-line data updating section  54 , off-line data transfer section  55 , update schedule management section  56 , off-line data DB  57 , in-page degree of importance DB  58 , HTML cache  59 , update schedule DB  60  and update frequency DB  61  are realized by, for example, the processing unit  26  ( FIG. 2 ) executing the program. 
     Details of the service data acquisition section  51 , update frequency discrimination section  52 , communication section  53 , off-line data updating section  54 , off-line data transfer section  55 , update schedule management section  56 , off-line data DB  57 , in-page degree of importance DB  58 , HTML cache  59 , update schedule DB  60  and update frequency DB  61  are described in detail below. 
     Here, off-line data update processing carried out by the GW server  11  will be explained with reference to  FIG. 4 . The update schedule management section  56  of the GW server  11  periodically requests the off-line data updating section  54  to start off-line data update processing based on a schedule stored in the update schedule DB  60 . The off-line data updating section  54  requests the service data acquisition section  51  to start the off-line data update processing. 
     Upon receiving the request to start the off-line data update processing from the off-line data updating section  54 , the service data acquisition section  51  acquires latest data of a Web page (hereinafter referred to as “page”) from the Web server  12 . The service data acquisition section  51  causes the HTML cache  59  to store the latest data acquired from the Web server  12 . 
     The update frequency discrimination section  52  determines the update frequency of each page with reference to a degree of importance per region of each page stored in the in-page degree of importance DB  58 . The update frequency discrimination section  52  updates the update frequency of each page stored in the update frequency DB  61  based on the update frequency of each page. 
     When the update frequency of each page stored in the update frequency DB  61  is updated, the update schedule management section  56  updates the schedule stored in the update schedule DB  60  according to a new update frequency. 
     The update frequency discrimination section  52  determines whether or not the latest data acquired from the Web server  12  has been updated using the degree of importance per region of each page stored in the in-page degree of importance DB  58 . The update frequency discrimination section  52  determines that the latest data has been updated when, for example, an update is detected in a region whose degree of importance is equal to or greater than a threshold. On the other hand, the update frequency discrimination section  52  determines that the latest data has not been updated when no update is detected in the region whose degree of importance is equal to or greater than the threshold although an update is detected in a region whose degree of importance is less than the threshold. 
     Upon determining that the latest data acquired from the Web server  12  has been updated, the off-line data updating section  54  updates the off-line data DB  57  with the latest data determined to have been updated out of the latest data stored in the HTML cache  59 . 
     Here, the off-line data referencing processing carried out by the mobile terminal  10  will be explained with reference to  FIG. 3 . First, the user browses the off-line data stored in the off-line data DB  39  using the Web browser  31  of the mobile terminal  10 . The local proxy  32  of the mobile terminal  10  acquires the page specified by the Web browser  31  from the off-line data DB  39  and returns the page to the Web browser  31 . When the page is displayed on the Web browser  31  for a predetermined time or more, the display region acquisition section  41  causes the region display time DB  38  to store a display time per region. 
     The on-line switching processing section  35  does not wait for the user to explicitly perform a reloading operation about the page whose latest information needs to be always referenced off-line within a content (e.g., seat reservation situation of Shinkansen (the New Trunk Line)) and automatically determines the necessity for an off-line reference simultaneously with the page display of the off-line data stored in the off-line data DB  39 . Upon determining that on-line reference is necessary, the on-line switching processing section  35  makes an on-line connection with the Web server  12 , acquires the latest data and updates the page display of off-line data to a page display of on-line data. This saves the user from having to manually specify and perform a reloading operation. 
     A page of off-line data is displayed such that real-time information within a page whose latest information within a content should always be referenced on-line is displayed, for example, in light color or with small characters. By this means, the on-line switching processing section  35  can indicate to the user that the real-time information displayed is not the latest but is being acquired from the Web server  12 . 
     The freshness determining section  33  determines whether or not real-time information (information whose latest information should always be referenced on-line) is included in the page. When the freshness determining section  33  determines that real-time information is included in the page, the on-line switching processing section  35  automatically makes an on-line connection with the Web server  12 , acquires latest data and replaces the page display of off-line data by the page display of on-line data. 
     Here, the processing of the mobile terminal  10  at the time of off-line data update will be explained with reference to  FIG. 3  and  FIG. 4 . For example, while browsing a page of off-line data stored in the off-line data DB  39  using the Web browser  31  of the mobile terminal  10 , if the user wants to browse the latest information of the page, the user performs a reloading operation from the Web browser  31 . 
     When the user performs the reloading operation, the reloading operation recording section  37  updates a reloading count stored in the reloading count DB  40 . The off-line data updating section  36  of the mobile terminal  10  transmits a reloading URL, contents stored in the reloading count DB  40  and contents stored in the region display time DB  38  from the communication section  34  to the GW server  11 . 
     The communication section  53  of the GW server  11  receives the reloading URL, contents stored in the reloading count DB  40  and contents stored in the region display time DB  38  from the communication section  34  of the mobile terminal  10 . The communication section  53  requests the off-line data updating section  54  to update the off-line data by specifying the received reloading URL. 
     The off-line data updating section  54  requests the service data acquisition section  51  to start off-line data update processing by specifying a reloading URL. Upon receiving the request to start off-line data update processing, the service data acquisition section  51  acquires the latest data of the page corresponding to the reloading URL from the Web server  12 . The service data acquisition section  51  causes the HTML cache  59  to store the latest data acquired from the Web server  12 . 
     The off-line data transfer section  55  updates the in-page degree of importance DB  58  based on the contents uploaded from the mobile terminal  10  and stored in the region display time DB  38 . The off-line data transfer section  55  updates the update frequency DB  61  based on the contents uploaded from the mobile terminal  10  and stored in the reloading count DB  40 . 
     The off-line data transfer section  55  acquires off-line data of the page corresponding to the reloading URL from the off-line data DB  57 , acquires an update frequency of each URL of the acquired off-line data from the update frequency DB  61  and creates an off-line data archive for transfer. The off-line data transfer section  55  transfers the created off-line data archive for transfer from the communication section  53  to the mobile terminal  10 . 
     The communication section  34  of the mobile terminal  10  receives the off-line data archive for transfer from the communication section  53  of the GW server  11 . The communication section  34  passes the received off-line data archive for transfer to the off-line data updating section  36 . The off-line data updating section  36  unarchives the off-line data archive for transfer and updates the off-line data stored in the off-line data DB  39 . The local proxy  32  acquires the data of the page corresponding to the reloading URL from the off-line data DB  39  and returns the data to the Web browser  31 . 
     Here, details of the off-line data update processing carried out by the GW server  11  will be explained with reference to a sequence diagram. The GW server  11  periodically makes an update check of pages stored in the Web server  12  and performs processing of updating data of pages stored in the off-line data DB  57  when an update is detected. 
       FIGS. 5A and 5B  are sequence diagrams illustrating an example of off-line data update processing carried out by the GW server  11 . The update schedule management section  56  of the GW server  11  starts to periodically execute off-line data update processing at a minimum update check frequency/interval (operation S 1 ). 
     The update schedule management section  56  acquires a URL list requiring an update check at a current date and time from the update schedule DB  60  (operation S 2 ).  FIG. 6  is a configuration diagram illustrating an example of the update schedule DB. The update schedule DB  60  in  FIG. 6  stores a schedule to make an update check of a content on the Web server  12 . 
     The update schedule DB  60  includes URL, update check frequency and final check date and time as data items. The update schedule management section  56  can determine the URL requiring an update check at the current date and time from the update check frequency and final check date and time stored in the update schedule DB  60 . The update schedule as illustrated in  FIG. 6  may be defined by the system  1  and/or a user. For example, based on a type of data (i.e., likelihood of frequent changes/updates), the update schedule may indicate frequent updates. 
     The update schedule management section  56  performs the following update check on each URL included in the URL list acquired in operation S 2  (operation S 3 ). The update schedule management section  56  requests the off-line data updating section  54  to make an update check by specifying a URL (operation S 4 ). 
     The off-line data updating section  54  requests the service data acquisition section  51  to acquire latest data by specifying a URL (operation S 5 ). The service data acquisition section  51  acquires the latest data of the page corresponding to the specified URL (operation S 6 ). The service data acquisition section  51  updates contents stored in the HTML cache  59  with the latest data acquired from the Web server  12  (operation S 7 ). 
       FIG. 7  is a configuration diagram illustrating an example of the HTML cache. The HTML cache  59  in  FIG. 7  stores HTML and a content such as an image acquired (downloaded) from the Web server  12 . The HTML cache  59  includes URL, final update date and time, and body data as data items. That is, the service data acquisition section  51  updates the URL, final update date and time, and body data stored in the HTML cache  59  with the latest data acquired from the Web server  12 . While content is illustrated as being an image, the present invention is not limited thereto. 
     The off-line data updating section  54  specifies a URL and acquires a list of terminal ID&#39;s of mobile terminals  10  checking the specified URL from the update frequency DB  61  (operation S 8 ). 
       FIG. 8  is a configuration diagram illustrating an example of an update frequency DB. The update frequency DB  61  in  FIG. 8  stores an update frequency of each page. 
     As illustrated in the update frequency DB  61  in  FIG. 8 , the update frequency for a certain URL has a value which differs from one terminal ID to another. Since a target region within a certain URL differs from one mobile terminal  10  to another or the update frequency differs from one region to another within a certain URL, the update frequency corresponding to the certain URL has a value which differs from one terminal ID to another. The update frequency DB  61  includes terminal ID, URL and update frequency (update interval) as data items. 
     The information browsing system  1  in  FIG. 1  makes an update check of a content on the Web server  12  and updates off-line data stored in the mobile terminal  10  based on the update frequency stored in the update frequency DB  61 . 
     The off-line data updating section  54  performs the following off-line data update on each terminal ID included in the list of terminal ID&#39;s acquired in operation S 8  (operation S 9 ). The off-line data updating section  54  requests the update frequency discrimination section  52  to make an update frequency check of off-line data by specifying a URL and user ID (operation S 10 ). 
     The update frequency discrimination section  52  acquires data (old HTML) from the off-line data DB  57  by specifying a terminal ID and URL (operation S 11 ).  FIG. 9  is a configuration diagram illustrating an example of the off-line data DB. The off-line data DB  57  in  FIG. 9  stores data which becomes a source to create off-line data to be transferred to the mobile terminal  10 . 
     The off-line data DB  57  includes terminal ID, URL, final update date and time, final transfer date and time, body data as data items. That is, the update frequency discrimination section  52  acquires final update date and time, final transfer date and time, and body data from the off-line data DB  57  by specifying a terminal ID and URL. 
     The update frequency discrimination section  52  acquires data (new HTML) from the HTML cache  59  by specifying a URL (operation S 12 ). The data (new HTML) acquired in operation S 12  becomes final update date and time, and body data. 
     The update frequency discrimination section  52  acquires an in-page importance degree list from the in-page degree of importance DB  58  by specifying a terminal ID and URL (operation S 13 ).  FIG. 10  is a configuration diagram illustrating an example of the in-page degree of importance DB. The in-page degree of importance DB  58  in  FIG. 10  stores regions in each page on which the mobile terminal  10  focuses attention. As illustrated in the in-page degree of importance DB  58 , regions of focus of attention within a certain URL differ from one mobile terminal  10  to another. The in-page degree of importance DB  58  includes terminal ID, URL, region (x 1 , y 1 )-(x 2 , y 2 ), and degree of importance (accumulated display time) as data items. The update frequency discrimination section  52  acquires the region (x 1 , y 1 )-(x 2 , y 2 ), degree of importance (accumulated display time) from the in-page degree of importance DB  58  by specifying a terminal ID and URL. 
     The update frequency discrimination section  52  calculates an update frequency of each page described in detail below with reference to a degree of importance per region of the page of each URL acquired from the in-page degree of importance DB  58  (operation S 14 ). 
     The update frequency discrimination section  52  updates the update frequency of the update frequency DB  61  by specifying a terminal ID, URL and update frequency (operation S 15 ). The update frequency discrimination section  52  requests the update schedule management section  56  to update the update check frequency by specifying a URL and update frequency (operation S 16 ). The update schedule management section  56  acquires the current update check frequency from the update schedule DB  60  by specifying a URL (operation S 17 ). 
     The update schedule management section  56  compares the update frequency specified by the update frequency discrimination section  52  in operation S 16  with the update check frequency acquired from the update schedule DB  60  in operation S 17  (operation S 18 ). 
     When the update frequency (new update check frequency) specified by the update frequency discrimination section  52  in operation S 16  is greater than the update check frequency (current update check frequency) acquired from the update schedule DB  60 , the update schedule management section  56  ignores a request for update of the update check frequency in operation S 16 . 
     On the other hand, when the update frequency (new update check frequency) specified from the update frequency discrimination section  52  in operation S 16  is smaller than the update check frequency (current update check frequency) acquired from the update schedule DB  60 , the update schedule management section  56  updates the update check frequency of the update schedule DB  60  to a new update check frequency by specifying a URL (operation S 19 ). 
     The update frequency discrimination section  52  returns information as to whether or not a flag indicating an update is set, that is, whether or not a target region within a new HTML is updated to the off-line data updating section  54  based on the result of operation S 107  or operation S 208  in the update frequency discrimination processing in operation S 14  (operation S 20 ). 
     When the target region within the new HTML is not updated, the off-line data updating section  54  ignores the target region even if regions other than the target region within the new HTML have been updated (operation S 21 ). When the target region within the new HTML has been updated, the off-line data updating section  54  acquires a new HTML from the HTML cache  59  by specifying a URL (operation S 22 ). 
     The off-line data updating section  54  updates the old HTML stored in the off-line data DB  57  to the new HTML acquired in operation S 22  by specifying a terminal ID and URL (operation S 23 ). To be more specific, the off-line data updating section  54  updates the final update date and time, final transfer date and time, and body data stored in the off-line data DB  57  by specifying a terminal ID and URL. The update schedule management section  56  updates the final check date and time of the update schedule DB  60  by specifying a URL (operation S 24 ). 
     The processing of creating the off-line data DB  57  from the beginning (from 0) is performed when a new service (content) on the Web server  12  is added to the information browsing system  1  or when a new mobile terminal  10  is added. The processing of creating the off-line data DB  57  from the beginning is as follows. 
     In the processing of creating the off-line data DB  57  from the beginning, the service data acquisition section  51  starts cyclic processing with a URL specified, performs the processing from operation S 4  onward of the sequence diagram illustrated in  FIGS. 5A and 5B  on all URL&#39;s included in the HTML of the specified URL and thereby creates off-line data. 
     Details of the off-line data referencing processing carried out by the mobile terminal  10  will be explained with reference to a sequence diagram here. When the user attempts to access the Web server  12  whose off-line data is stored in the off-line data DB  39  using the Web browser  31  on the mobile terminal  10 , the local proxy  32  reads an HTML file and image file corresponding to a specified URL from the off-line data DB  39  and returns the files, and the user can thereby browse the content of the Web server  12  even while being off-line. While browsing of a page, if a region in the page is displayed for a predetermined time or more, the accumulated display time of each region is updated. 
       FIG. 11  is a sequence diagram illustrating an example of off-line data referencing processing carried out by the mobile terminal  10 . When the user attempts to access the Web server  12  whose off-line data is stored in the off-line data DB  39  using the Web browser  31  on the mobile terminal  10  by specifying a URL, the Web browser  31  requests the local proxy  32  to acquire the page by specifying the URL (operation S 31 ). 
     The local proxy  32  acquires the page from the off-line data DB  39  by specifying a URL and returns the page to the Web browser  31  (operation S 32 ). Suppose a region in the page has been displayed for a predetermined time or more on the Web browser  31  (operation S 33 ). The Web browser  31  reports the display region to the display region acquisition section  41  by specifying a URL, region and display time (operation S 34 ). The display region acquisition section  41  updates the accumulated display time of the region display time DB  38  based on the URL, region and display time included in the display region report from the Web browser  31  (operation S 35 ). 
       FIG. 12  is a configuration diagram illustrating an example of a region display time DB. The region display time DB  38  in  FIG. 12  stores an accumulated display time of each region in the page. The region display time DB  38  in  FIG. 12  includes URL, region and accumulated display time as data items. 
     Details of the mobile terminal  10  at the time of off-line data update will be explained with reference to a sequence diagram here. For example, while browsing a page of off-line data stored in the off-line data DB  39  using the Web browser  31  of the mobile terminal  10 , if the user wants to browse the latest information of the page, the user performs a reloading operation from the Web browser  31 . 
     When the user performs the reloading operation, the mobile terminal  10  makes an on-line connection with the GW server  11  and acquires a latest version of the page which is the reloading target. In this case, the mobile terminal  10  also updates the off-line data stored in the off-line data DB  39  simultaneously. 
     The off-line data stored in the off-line data DB  39  of the mobile terminal  10  is updated not only at the time of reloading operation but also when the final update date and time of the off-line data becomes old relative to the update frequency. The processing in this case corresponds to operations S 46  to S 62  illustrated in the sequence diagram of  FIGS. 13A and 13B  which is described in detail below. 
     The GW server  11  stores upload data during an on-line connection in the in-page degree of importance DB  58  so as to be used to update future off-line data using the accumulated display time per region in each uploaded URL as the degree of importance. Furthermore, when the reloading count of each uploaded URL is large, the GW server  11  sets the update frequency of the off-line data higher frequency. 
       FIGS. 13A and 13B  are sequence diagrams illustrating an example of processing at the time of off-line data update of the mobile terminal  10 . When the user performs a reloading operation (operation S 41 ), the Web browser  31  requests the local proxy  32  for reloading by specifying a URL (operation S 42 ). 
     The local proxy  32  requests the reloading operation recording section  37  to record the reloading operation by specifying a URL (operation S 43 ). The reloading operation recording section  37  updates the reloading count stored in the reloading count DB  40  based on the specified URL (operation  44 ). 
       FIG. 14  is a configuration diagram illustrating an example of a reloading count DB. The reloading count DB  40  in  FIG. 14  stores the reloading count of the reloading operation carried out by the user for each page. The reloading count DB  40  includes URL and reloading count as data items. 
     The local proxy  32  requests the off-line data updating section  36  to update the off-line data (operation S 45 ). The off-line data updating section  36  acquires a reloading count list including all combinations of URL&#39;s and reloading counts from the reloading count DB  40  (operation S 46 ). The off-line data updating section  36  acquires each region display time list including all combinations of URL&#39;s, regions and accumulated display times from the region display time DB  38  (operation S 47 ). 
     The off-line data updating section  36  requests the communication section  34  to transmit an off-line data update request including the reloading URL, reloading count list and each region display time list (operation S 48 ). The communication section  34  transmits the off-line data update request including the reloading URL, reloading count list and each region display time list to the communication section  53  of the GW server  11  (operation S 49 ). 
     Upon receiving the off-line data update request including the reloading URL, reloading count list and each region display time list from the communication section  34  of the mobile terminal  10 , the communication section  53  requests the off-line data updating section  54  to make an update check by specifying the reloading URL (operation S 50 ). The update check carried out by the off-line data updating section  54  is similar to the aforementioned periodically carried out update check. 
     The communication section  53  transmits the off-line data acquisition request including the terminal ID, reloading count list and each region display time list to the off-line data transfer section  55  (operation S 51 ). The off-line data transfer section  55  updates the in-page degree of importance DB  58  by specifying a terminal ID, URL, region and accumulated display time (operation S 52 ). 
     The off-line data transfer section  55  extracts the URL included in the reloading count list and updates the update frequency of each extracted URL (operation S 53 ). The off-line data transfer section  55  updates the update frequency DB  61  with the terminal ID, URL and the new update frequency updated in operation S 53  (operation S 54 ). 
     The off-line data transfer section  55  acquires body data which are the HTML file and image file or the like updated after the previous off-line data transfer from the off-line data DB  57  by specifying a terminal ID and current date and time (operation S 55 ). 
     The off-line data transfer section  55  starts to acquire the update frequency of the URL corresponding to each piece of body data acquired in operation S 55  (operation S 56 ). The off-line data transfer section  55  acquires the update frequency from the update frequency DB  61  by specifying a terminal ID and URL (operation S 57 ). The off-line data transfer section  55  creates an off-line data archive for transfer from the body data which are the HTML file and image file or the like acquired from the off-line data DB  57  in operation S 55  and the update frequency acquired in operation S 57  (operation S 58 ). 
     In operations S 59  to S 61 , the off-line data archive for transfer is transferred from the off-line data transfer section  55  of the GW server  11  to the off-line data updating section  36  of the mobile terminal  10  via the communication section  53  of the GW server  11  and the communication section  34  of the mobile terminal  10 . The off-line data updating section  36  unarchives the off-line data archive for transfer and saves the unarchived off-line data in the off-line data DB  39  (operation S 62 ). 
       FIG. 15  is a configuration diagram illustrating an example of the off-line data DB. The off-line data DB  39  in  FIG. 15  stores body data of each URL and related information (final update date and time, final transfer date and time, and update frequency). The off-line data DB  39  includes URL, final update date and time, final transfer date and time, update frequency and body data as data items. 
     The local proxy  32  then acquires data of the page of the reloading URL from the off-line data DB  39  (operation S 63 ). The local proxy  32  returns the data of the page corresponding to the reloading URL acquired in operation S 63  to the Web browser  31 . 
     In the processing at the time of off-line data update illustrated in  FIGS. 13A and 13B , when an off-line data archive to be transferred to the mobile terminal  10  is created, it is also possible to adopt a method of transferring the difference from the off-line data already stored in the mobile terminal  10  and merging the difference on the mobile terminal  10  side. Furthermore, in the processing at the time of off-line data update illustrated in  FIGS. 13A and 13B , when an off-line data archive to be transferred to the mobile terminal  10  is created, it is also possible to adopt a method of transferring only a target region which is described in detail below. 
     Examples of the target region determination method carried out by the display region acquisition section  41  include four methods described below. In addition, a method of extracting a region where scrolling becomes slow as a target region. 
     A first method of target region determination performed by the display region acquisition section  41  may be such that the mobile terminal  10  side places importance on the update of a region with a long display time, whereas the mobile terminal  10  does not give much consideration to updates of other regions.  FIG. 16  is an image diagram of the first method of target region determination performed by the display region acquisition section  41 . 
     In  FIG. 16 , the display region acquisition section  41  of the mobile terminal  10  stores regions  102  and  103  on a page  100  displayed for a predetermined time or more in a screen size  101  of the mobile terminal  10  as target regions in the region display time DB  38 . 
     A second method of target region determination performed by the display region acquisition section  41  may be such that a page displayed on the mobile terminal  10  is delimited in predetermined units and importance is placed on an update of each predetermined delimitation unit.  FIG. 17  is an image diagram of the second method of the target region determination carried out by the display region acquisition section  41 . 
     In  FIG. 17 , an accumulated display time of each block is recorded in units of a block of 8×8 pixels on a page  100 . For example, in  FIG. 17 , each block is expressed by XY coordinates and the accumulated display time of each block (X 2 Y 10 -X 8 Y 18 ) of the display region portion expressed by a screen size  101  of the mobile terminal  10  is updated. 
     A third method of target region determination performed by the display region acquisition section  41  may be such that importance is placed on an update around a character string included in the display region of the screen size  101  of the mobile terminal  10 . For example, according to the first target region determination method, when emergency news or the like is inserted and the display is thereby shifted, attention may be focused on an unintended region. 
     In order to correctly judge the target region even when emergency news or the like is inserted and the display is thereby shifted, according to the third method of the target region determination, a target region is extracted based on a character string included in the display region. 
     The display region acquisition section  41  extracts a target region based on the character string included in the display region. When extraction processing is performed on the entire page  100  in this case, the processing load is large, and therefore the display region acquisition section  41  extracts a character string from a region having a long display time. Using a method of specifying a region by simply using only a character string, it is difficult to specify the region when the same character string is included. 
     Therefore, the third method of target region determination calculates XPath corresponding to the top left of the display region based on the HTML structure, lists character strings included in the display region, combines XPath corresponding to the location at the top left of the display region and the character strings included in the display region, stores the character strings in the region display time DB  38  illustrated in  FIG. 18 , and can thereby allow the region to be specified. 
     A fourth method of target region determination performed by the display region acquisition section  41  may be such that the mobile terminal  10  side places importance on an update of the region around a selected link, whereas the mobile terminal  10  does not give much consideration to updates of other regions. For example, when the user selects a link and moves to the linked page, the region around the selected link within the source page is regarded as a target region. 
     A fifth method of target region determination performed by the display region acquisition section  41  may be such that importance is placed on an update of a region around an anchored link coming in a jump, whereas not much consideration is given to updates of other regions. For example, when the link selected by the user is an anchored link, a region around the anchor in the linked page is regarded as a target region. 
       FIG. 19  is an image diagram of the fourth and fifth methods of target region determination carried out by the display region acquisition section  41 . According to the fourth target region determination method, when, for example, the user selects a link on a page  100  and moves to a linked page  104 , a region around the link selected in the linked page  100  (display region of a screen size  101  of the mobile terminal  10 ) is regarded as a target region. 
     Furthermore, according to the fifth method of target region determination, when, for example, a link selected by the user is an anchored link, a region  105  around the anchor in the linked page  104  is regarded as a target region. While specific methods (processes) are discussed herein, the present invention is not limited to exact processing of these methods and may include any variations including combination thereof. 
     As for the update frequency discrimination method carried out by the update frequency discrimination section  52 , the update frequency (update interval) of the entire page is calculated through averaging from an update history of past pages. In a check to determine whether or not the entire page has been updated, updates of regions where the degree of importance of the regions in the page is less than a threshold are ignored. 
       FIG. 20  is a flowchart illustrating a procedure for update frequency discrimination processing carried out by the update frequency discrimination section  52 . The update frequency discrimination section  52  acquires data (old HTML) from the off-line data DB  57  by specifying a terminal ID and URL (operation S 100 ). The update frequency discrimination section  52  acquires data (new HTML) from the HTML cache  59  by specifying a URL (operation S 101 ). 
     The update frequency discrimination section  52  acquires the in-page importance degree list from the in-page degree of importance DB  58  by specifying a terminal ID and URL (operation S 102 ). To be more specific, the update frequency discrimination section  52  acquires the region and degree of importance (for example, accumulated display time) from the in-page degree of importance DB  58  by specifying a terminal ID and the URL. 
     The update frequency discrimination section  52  extracts one region and degree of importance at a time from the acquired in-page importance degree list (operation S 103 ). The update frequency discrimination section  52  determines whether or not the extracted degree of importance is less than a threshold (operation S 104 ). 
     When the extracted degree of importance is less than the threshold, the update frequency discrimination section  52  returns to operation S 103  and extracts the next region and degree of importance from the in-page importance degree list. On the other hand, when the extracted degree of importance is not less than the threshold, the update frequency discrimination section  52  determines whether or not there is any difference in the region (target region) extracted in operation S 103  between the old HTML acquired in operation S 100  and the new HTML acquired in operation S 101  (operation S 105 ). 
     When there is no difference in the region extracted in operation S 103  between the old HTML acquired in operation S 100  and the new HTML acquired in operation S 101 , the update frequency discrimination section  52  extracts the next region and degree of importance from the in-page importance degree list (operation S 103 ). 
     When there is a difference in the region extracted in operation S 103  between the old HTML acquired in operation S 100  and the new HTML acquired in operation S 101 , the update frequency discrimination section  52  sets a flag indicating an update (operation S 106 ) and then extracts the region and the degree of importance from the in-page importance degree list (operation S 103 ). When all regions and degrees of importance have been extracted from the acquired in-page importance degree list, the update frequency discrimination section  52  moves to operation S 107  and determines whether or not a flag indicating an update is set. 
     When no flag indicating an update is set, the update frequency discrimination section  52  finishes the update frequency discrimination processing illustrated in  FIG. 20 . When a flag indicating an update is set, the update frequency discrimination section  52  calculates an update interval m, for example, by dividing a total elapsed time T by an update count n (operation S 108 ). The update frequency discrimination section  52  updates the update interval (update frequency) of the update frequency DB  61  by specifying a terminal ID and URL (operation S 109 ). 
     After operation S 109 , the update frequency discrimination section  52  returns information as to whether the target region in the new HTML has been updated to the off-line data updating section  54 . By returning the information that the target region in the new HTML has been updated to the off-line data updating section  54 , the update frequency discrimination section  52  can cause the off-line data updating section  54  to update the old HTML stored in the off-line data DB  57  to a new HTML. 
     However, in operation S 108  of  FIG. 20 , when there is a variation in the update frequency, for example, when the update frequency is high in the daytime and low in the nighttime or when the update frequency is high on weekdays and low on holidays or the like, simply taking the average may cause the update frequency to be calculated to be relatively lower than a value expected by the user. 
     Therefore, in operation S 108  of  FIG. 20 , a method of taking the average of the time during which the user uses the mobile terminal  10  may be adopted as illustrated in  FIG. 21 .  FIG. 21  is an image diagram illustrating an example of the method of taking the average of the time during which the user uses the mobile terminal  10 . 
     The update frequency discrimination processing when the aforementioned third method of target region determination is used is as illustrated in  FIG. 22 .  FIG. 22  is a flowchart illustrating another procedure for the update frequency discrimination processing carried out by the update frequency discrimination section  52 . The update frequency discrimination processing when the third method of target region determination is used compares the display contents of the old HTML with the display contents of the new HTML in character strings. When no character strings of the old HTML are found in the new HTML, such character strings are ignored. That is, the update frequency discrimination processing when the third method of target region determination is used uses character strings that will not change even if the page is updated. 
     The processing in operations S 200  to S 204  is similar to the processing in operations S 100  to S 104  of  FIG. 20  and explanations thereof will be omitted. When the extracted degree of importance is not less than a threshold in operation S 204 , the update frequency discrimination section  52  determines whether or not any character string is found within the target region of the new HTML (operation S 205 ). 
     When no character string is found within the target region of the new HTML, the update frequency discrimination section  52  extracts the next region and degree of importance from the in-page importance degree list (operation S 203 ). When a character string is found within the target region of the new HTML, the process moves to operation S 206 . The processing in operations S 206  to S 210  is similar to the processing in operations S 105  to S 109  of  FIG. 20  and explanations thereof will be omitted. 
     As described so far, the information browsing system  1  of an embodiment automatically adjusts the update frequency per page based on the user operation on the mobile terminal  10 . That is, the information browsing system  1  determines the target region in the page based on the user operation on the mobile terminal  10  side and determines the update frequency of the entire page with priority given to the update frequency of the target region. Furthermore, when the user explicitly performs a reloading operation on the mobile terminal  10  side, the information browsing system  1  increases the update frequency. 
     Therefore, the information browsing system  1  ( FIG. 1 ) of an embodiment transfers an off-line content when a region of interest for the user is updated, and can thereby suppress unnecessary communication and reduce a communication charge and battery consumption. Furthermore, automatically adjusting the update frequency based on a normal browsing operation of the user eliminates the necessity for any special operation of the user to adjust the update frequency of an off-line content. Thus, eliminating the necessity for any special operation of the user to adjust the update frequency of the off-line content has a great effect for the mobile terminal having a limited input interface. 
     The embodiments can be implemented in computing hardware (computing apparatus) and/or software, such as (in a non-limiting example) any computer that can store, retrieve, process and/or output data and/or communicate with other computers. The results produced can be displayed on a display of the computing hardware. A program/software implementing the embodiments may be recorded on computer-readable media comprising computer-readable recording media. The program/software implementing the embodiments may also be transmitted over transmission communication media. Examples of the computer-readable recording media include a magnetic recording apparatus, an optical disk, a magneto-optical disk, and/or a semiconductor memory (for example, RAM, ROM, etc.). Examples of the magnetic recording apparatus include a hard disk device (HDD), a flexible disk (FD), and a magnetic tape (MT). Examples of the optical disk include a DVD (Digital Versatile Disc), a DVD-RAM, a CD-ROM (Compact Disc-Read Only Memory), and a CD-R (Recordable)/RW. An example of communication media includes a carrier-wave signal. 
     Further, according to an aspect of the embodiments, any combinations of the described features, functions and/or operations can be provided. 
     All examples and conditional language recited herein are intended for pedagogical purposes to aid the reader in understanding the principles of the invention and the concepts contributed by the inventor to furthering the art, and are to be construed as being without limitation to such specifically recited examples and conditions, nor does the organization of such examples in the specification relate to a showing of the superiority and inferiority of the invention. Although the embodiments of the present inventions have been described in detail, it should be understood that the various changes, substitutions, and alterations could be made hereto without departing from the spirit and scope of the invention, the scope of which is defined in the claims and their equivalents.