Abstract:
A purpose of the invention is to transmit data certainly even if some trouble happens on one of communicating lines and to enhance a masking effect of information. In the case that data including A, B and C stored in a device at a place transmits to another device  20  located at the different place, communicating lines including at least three lines are connected and divided data portion AB, BC and CA is transmitted to the communicating lines, respectively.

Description:
[0001]    The entire disclosure of Japanese Patent Application No. 2000-134117 filed on May 8, 2000 including specification, claims, drawings and summary is incorporated herein by reference in its entirety.  
         BACKGROUND OF THE INVENTION  
         [0002]    The invention relates to data transmitting means with high communicating reliability and high masking performance by utilizing a plurality of communicating lines when data is transmitted to a remote place.  
           [0003]    It has been used a network communication such as a leased line, a telephone communication line and a radio communication line as means for transmitting data stored in a device such as a personal computer and a workstation to a device such as a personal computer or a workstation located at a remote place.  
           [0004]    Recently, lines commonly used with the third parties such as Internet are used much more than the leased lines.  
           [0005]    In the case of communicating with a network, it has been often happened that transmitting data was intermitted caused by troubles on the network such as shutdown of communication line and fault of the transmitting device. In a conventional art, in such a case, communicating devices are handshaked each other so as to detect missing part of the data and retry to transmit the missing part of the data.  
           [0006]    However, it has to spend a redundant time to handshake and retry in the above described method. Further, the data can not be transmitted if the transmitting line is only a single line and any trouble is still happened on the single line.  
           [0007]    On the other hand, in the case of utilizing the lines commonly used with the third parties such as the Internet, it can not be denied that the transmitted data is observed by the third parties. It would be difficult to mask the data.  
         SUMMARY OF THE INVENTION  
         [0008]    To resolve the above disadvantage, a first aspect of a distributed communicating device according to the present invention is characterized of utilizing at least three communication lines and dividing transmitted the data to each communication lines in the case of transmitting the data to a device located at a remote place.  
           [0009]    To resolve the above disadvantage, a second aspect of the distributed communication device according to the present invention is characterized of dividing data and transmitting the divided data in the distributed communication device so as to recover an optional portion of the divided data even if the optional portion is destroyed.  
           [0010]    To resolve the above disadvantage, a third aspect of the distributed communicating device according to the present invention is characterized of not analyzing transmitted data unless number of divided data is equal or more than a predetermined number, that is, the total divided number minus 1. 
       
    
    
     BRIEF EXPLANATION OF THE DRAWINGS  
       [0011]    [0011]FIG. 1 shows an idea for transmitting data according to the present invention.  
         [0012]    [0012]FIG. 2 shows the first embodiment according to the present invention for showing a connecting example of communicating lines.  
         [0013]    [0013]FIG. 3 shows the second embodiment according to the present invention for showing an example of a remote control plant. 
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0014]    As shown in FIG. 1, if data is transmitted from a transmitting device  10  to a receiving device  20  located at a remote place, at least three communicating lines (transmitting paths)  30  are necessary.  
         [0015]    In the case that a total number of the communicating lines  30  is N, an inequality of N 3 is existed:  
         [0016]    In the transmitting device, transmitted data is divided into N parts. A data dividing method is a redundancy distributing method, which has been used in a disk array and so on.  
         [0017]    As the redundancy distribution method, it has been known the following method so called as “laid” One of the methods is a method so called as “striping”, wherein one file is divided into a plurality of parts and the parts are simultaneously written in a plurality of hard discs so as to accomplish a high speed file access.  
         [0018]    In accordance with the striping method, the high speed file access can be accomplished by distributing the operation.  
         [0019]    Further, there is also a method so called as “mirroring” wherein one file is simultaneously written in a plurality of hard discs so as to improve the safety performance of a hardware equipment.  
         [0020]    In the mirroring method, it means that “back up” is always operated in a spare hard disc. Even if anyone of hard discs is crashed, the crashed data can be recovered by the other hard disc.  
         [0021]    In the present invention, at least three communicating lines are utilized by combining the striping method and the mirroring method.  
         [0022]    In the case that one data is divided into N parts, even if anyone of divided data is destroyed or crashed, an original data can be recovered from (N−1) divided portion of the data in a distribution method according to the present invention.  
         [0023]    For example, one data is divided into three parts such as regions A, B and C and two regions are selected from the three regions so as to form the divided data portions AB, BC and CA.  
         [0024]    In the method, unless at least two divided data portions, that is, (N−1) data divided portions, can be received, the original data can not be analyzed.  
         [0025]    Such divided data portions are transmitted to the receiving device  20  through N communication lines  30 .  
         [0026]    The receiving device  20  receives divided data portions through N communication lines in order to form the original data.  
         [0027]    By repeating the operation, the data can be transmitted from the transmitting device  10  to the receiving device  20 .  
         [0028]    In accordance with the present invention, even if some trouble are happened on one of the communicating lines  30  and one of the lines can not transmit any data, the original data can be correctly transmitted.  
         [0029]    In the above described case, even if one of the communicating lines meets some trouble and one divided data portions, for example, the divided data portion AB, can not be transmitted through the communicating line, the data consisting the three regions A, B and C can be recovered by the divided data portions BC and CA which can be received by the receiving device  20 .  
         [0030]    Further, if someone eavesdrops information, two communicating lines  30  out of three communicating lines  30  have to be monitored so that masking performance with respect to information can be improved.  
         [0031]    In the distributed communicating device according to the present invention, the reliability and the masking performance of the communicating lines can be improved by combining the conventional striping method and the conventional mirroring method.  
         [0032]    As similarly, in the case that one data is divided into four regions A, B, C and D, divided data portions, ABC, BCD, CDA and DAB are formed by optionally selecting three regions out of the four regions so as to transmit the divided data portions through four communicating lines, even if some trouble happen on the two communicating lines, the original data can be recovered.  
         [0033]    Further, it is possible to divide one data into a lot of regions, A, B, C, D, . . . and select optional number of the regions from the regions A, B, C and D, . . . so as to transmit the divided and selected data portions through a plurality of communicating lines.  
         [0034]    It is necessary to previously determine a data distributed transmitting method between the transmitting device  10  and the receiving device  20 .  
         [0035]    The transmitting device  10  may code or compress transmitted data and the receiving device  20  may decode or defrost the data.  
         [0036]    Although a dividing unit is not restricted, 8 bits, 7 bits are acceptable and the data may be divided by every one byte.  
         [0037]    In addition, one data may be divided into three regions A, B and C. The each divided data A, B and C may be transmitted through three communicating lines, respectively.  
         [0038]    In such a case, the original data can be recovered by monitoring the all three communicating lines so that the masking performance with respect to information can be highly improved.  
         [0039]    However, if anyone of three communicating lines is in fault, the original data can not be recovered.  
         [0040]    In the case that one data is divided into two parts and the divided data are transmitted through two communicating lines, the masking performance can be improved.  
         [0041]    Detailed embodiments according to the present invention will be explained with reference to the accompanying drawings.  
         [0042]    [Embodiment 1] 
         [0043]    A distributed communication device of the first embodiment according to the present invention is shown in FIG. 2.  
         [0044]    In the first embodiment, the different kinds of communication lines are utilized.  
         [0045]    As shown in FIG. 2, as a communicating line  30  for transmitting data from a transmitting device  10  to a receiving device  20  located at a remote place, the first line is a satellite line  31 , the second line is a telephone line  32  and the third line is an internet line  33 .  
         [0046]    On the satellite line  31 , data from the transmitting device  10  is coded by a converter  41  and transmitted through a communicating satellite  42 . At the receiving device  20 , the data is decoded by a converter  43 .  
         [0047]    On the telephone line  32 , data is coded by a modem  51  and the coded data is transmitted through a general line. At the receiving device  20 , the data is decoded by the converter  43 .  
         [0048]    On the Internet line  33 , data is transmitted through a provider  61 . At the receiving device  20 , the data is received through another provider  62 .  
         [0049]    In the embodiment, for example, one data is divided into three regions A, B and C and then two regions are optionally selected from the three regions so as to form divided data portions AB, BC and CA at the transmitting device  10 . The divided data portions is transmitted to the receiving device  20  through the satellite line  31 , the telephone line  32  and the internet line  33 , respectively. The receiving device  20  receives the divided data portions from the three communication lines  30  so as to recover the original data. Such an operation is repeated.  
         [0050]    Thereby, one data can be transmitted from the transmitting device  10  to the receiving device  20 .  
         [0051]    In the first embodiment, even if one of the communicating lines  30  meets some trouble, for example, the telephone line  32  is in fault, the original data can be recovered. Since the divided data portions BC and CA are received through the satellite line  31  and the Internet line  33  by the receiving device  20 .  
         [0052]    At least two divided portions out of the three divided portions AB, BC and CA are necessary to analyze a content of the data so that the masking performance with respect to the information can be improved.  
         [0053]    In the first embodiment, the satellite line  31 , the telephone line  32  and the Internet line  33  are used as a communicating line  30 . However, the other kinds of lines are acceptable.  
         [0054]    For example, leased lines or LAN (local area network) provided at factories and works, radio communication and lines for CATV (cable television) may be used. Regarding the telephone line  32 , ISDN lines are also acceptable except normal analog lines.  
         [0055]    Further, it is acceptable one way communication system from the transmitting device  10  to the receiving device  20  as well as two way communication system.  
         [0056]    [Embodiment 2] 
         [0057]    A distributed communicating device of a second embodiment according to the present invention is shown in FIG. 3.  
         [0058]    The second embodiment is suitable for a remote observation with respect to a plant.  
         [0059]    At the plant  100 , a gas turbine  101  is controlled by a controlling device  102  and data including control data is recorded by a data recording device  103 . On the other hand, at a monitoring section  200  located at a remote place from the plant  100 , a data control device  201  and a monitor  202  are provided. The control data has to be transmitted from the plant  100  to the monitoring section  200 .  
         [0060]    Thus, the plant  100  and the monitoring section  200  are communicated by a satellite communication line  310 , a telephone line  320  and an internet line  330 .  
         [0061]    On the satellite line  310 , data from the plant  100  is coded by a converter  410  and the coded data is transmitted through the satellite line  310 . At the monitoring section  200 , the coded data is decoded by a converter  430 .  
         [0062]    On the telephone line  320 , the data is coded by a modem  510  and the coded data is transmitted through a general line. At the modem  520 , the coded data is decoded and transmitted to the monitoring section  200 .  
         [0063]    On the Internet line  330 , the data is transmitted through the provider  610  and the data is received at the monitoring section  200  through the provider  62 .  
         [0064]    In the second embodiment, the data recording device  103  of the plant  100  divides one data into three regions A, B and C and optionally select two regions from the three regions so as to form divided data portions AB, BC and CA. The divided data portions is transmitted to the monitoring section  200  through the satellite line  310 , the telephone line  320  and the internet line  330 , respectively.  
         [0065]    At the monitoring section  200 , divided data portions transmitted through the three communication lines  300  are received and the original data is recovered by the data controlling device  201 . Such an operation is repeated. If necessarily, the data is displayed on the monitor  202 .  
         [0066]    Thus, the data such as the control data from the local plant  100  can be transmitted to the monitoring section  200 .  
         [0067]    In the embodiment, even if one of the communicating lines  300  meets some trouble and the data portion can not be transmitted the data can be correctly transmitted.  
         [0068]    In the case of earthquake occurrence and the telephone line  320  destroyed, the data including the control data can be transmitted from the local plant  100  to the monitoring section  200  if the remained two lines, that is, the satellite line  310  and the internet line  330  are still operable condition.  
         [0069]    Further, at least two divided data portions out of the divided data portions AB, BC and CA are necessary in order to analyze the content of the data, the masking performance with respect to information can be improved.  
         [0070]    [The Other Embodiments] 
         [0071]    As one embodiment of a distributed communicating device according to the present invention, fixed data such as a text file and a still picture data can be transmitted to a remote place.  
         [0072]    In another embodiment, moving picture data can be transmitted to a remote place as a remote picture observation device.  
         [0073]    Further, the present invention can transmit analysis data such as vibration analysis to a remote place so that the present invention can be utilized as a two way communication between two points (telephone).  
         [0074]    The present invention can be utilized to transmit music distribution data such as KARAOKE data through communicating lines.  
         [0075]    As described above with reference to the embodiments, a feature of a distributed communicating device according to the present invention is to transmit data in a device located at one place to the different device located at a different place, wherein at least three communicating lines are utilized and one data is divided and transmitted through the corresponding communicating lines, respectively. Therefore, at least two communicating lines have to be monitored so as to recover the original data so that the masking performance with respect to the data can be improved.  
         [0076]    That is, a divided data portion for each communicating line is one of the divided data portions, which does not have any important meaning independently. Even if the third party observes/eavesdrops one of the divided data transmitted on a sheared line, the original data can not be recovered. The masking performance with respect to the data can be improved.  
         [0077]    Another feature of the distributed communicating device according is to transmit divided data at the distributed communicating device, wherein the original data can be recovered even if an optional divided data portion is destroyed. Anyone of the communicating lines is in fault, the original data can be recovered by the remained divided data portions. A data transmitting error can be avoided due to troubles on communicating lines.  
         [0078]    Another feature of the distributed communicating device according to the present invention is to transmit the divided data portions at the distributed communication device, wherein the data is divided into N divided data portions and the original data can not be analyzed unless at least N−1 divided data portions are received. The masking performance with respect to information can be improved.  
         [0079]    The present invention is, of course, in no way restricted to the specific disclosure of the specification and drawings, but also encompasses any modification within the scope of the appended claims.