JP4964282B2 - Data transfer device, data transfer method and program, and data transfer system - Google Patents

Description

  The present invention relates to a data transfer apparatus, a data transfer method, a program therefor, and a data transfer system that transfer data acquired from the outside to a server.

  Conventionally, various techniques have been proposed to prevent the efficiency of data transfer from being lowered even if the line state (line quality) fluctuates during data communication (for example, Patent Document 1 and Patent Document 2).

  Patent Document 1 discloses a data transfer method for determining the frame length to be transmitted next time depending on the success / failure state of frame transmission.

  Patent Document 2 also measures the level of Ec / Io (pilot signal strength vs. total received signal strength) of radio signals in wireless communication to determine whether the line status is in a recovery trend or a deterioration trend. Based on the result, a technique for performing communication by setting the data size of one packet is disclosed.

JP-A-11-122226 JP 2005-20550 A

  However, in the technique disclosed in Patent Document 1, if the connection is cut off during communication, the data transmitted until then is lost. Therefore, after re-establishing the connection, the data is transmitted from the beginning. I need to fix it.

  In the technique disclosed in Patent Document 2, data to be transmitted is transferred by a plurality of sessions, and when the line state is good, the number of sessions is increased. Thereby, a huge amount of data is efficiently transferred. A session ID is assigned to the session, and both hosts that perform data communication store and hold the session ID. Both hosts can request and respond to each other for a session ID, so that even if communication is interrupted, they can resume from the session with that session ID, and there is no need to retransmit data from the beginning.

  However, since the amount of data to be transferred in one session is fixed, the line condition is bad, and if the session is disconnected and retransmitted, the session is likely to be disconnected again in the middle Even if it exists, there exists a problem that resending must be repeated with the same data amount.

  Accordingly, there is a need for a proposal of a new technique for avoiding a decrease in data transfer efficiency caused by a disconnection in the middle of communication that may occur when the line condition is poor.

  The present invention has been made in view of such circumstances, and by adjusting the amount of data to be transmitted in one session according to the line state, the efficiency of data transfer caused by disconnection in the middle of communication It is an object of the present invention to provide a data transfer apparatus, a data transfer method, a program for the data transfer system, and a data transfer system that prevent the degradation.

In order to achieve the above object, a data transfer apparatus according to the present invention provides:
Data acquisition means for acquiring data from other devices and storing the data in a buffer;
Communication means for transmitting data stored in the buffer to a server connected via a predetermined network;
Line state acquisition means for acquiring line state data relating to the line state;
Line state storage means for accumulating and storing the line state data acquired by the line state acquisition means;
Based on the line state data stored in the line state storage means and the total amount of data stored in the buffer, the amount of data that can be transmitted in one session with the server can be transmitted. A transmission data amount determining means for determining a data amount;
Said communication means, if the total amount of data stored in the buffer is greater than the transmittable data amount, and transmits the data stored in the buffer is divided into at least two or more sessions, the line status memory The line state data stored in the means includes a data transfer amount in the previous session, and the transmission data amount determining means includes the data transfer amount in the previous session and the data transfer amount in the previous session. The amount of transmittable data is determined based on the success or failure of .

  ADVANTAGE OF THE INVENTION According to this invention, it becomes possible to prevent the efficiency fall of the data transfer resulting from the disconnection in the middle of communication.

It is a block diagram which shows the structure of the data transfer system which concerns on one Embodiment of this invention. It is a block diagram which shows the structure of a wide area communication part. It is a figure which shows an example of the line state data stored in a line state memory | storage part. It is a figure which shows an example of the environmental information stored in an environmental information storage part. It is a flowchart which shows the procedure of the process performed with a data transfer apparatus. It is a flowchart which shows the procedure of a data transmission process.

  Hereinafter, a data transfer system according to an embodiment of the present invention will be described in detail with reference to the drawings.

  FIG. 1 is a block diagram showing the configuration of the data transfer system according to this embodiment. As shown in FIG. 1, the data transfer system includes a data transfer device 10 and a data collection server 20.

  In the present embodiment, the data transfer device 10 plays a role as a data logger that collects various log data related to solar power generation from one or a plurality of devices. The data transfer device 10 transfers the collected log data to a data collection server 20 connected to a wide area network N such as the Internet.

  In the present embodiment, TCP / IP (Transmission Control Protocol / Internet Protocol) is used as a communication protocol between the data transfer apparatus 10 and the data collection server 20, and HTTP (HyperText Transfer Protocol) is used as a data transfer protocol. use. The data transfer apparatus 10 has an HTTP client function, and the data collection server 20 has an HTTP server function. In addition, data transfer may be performed using a protocol such as FTP (File Tranfer Protocol) or SMTP (Simple Mail Transfer Protocol).

  The data transfer apparatus 10 includes a data acquisition unit 101, a buffer 102, a wide area communication unit 103, a line state acquisition unit 104, a line state storage unit 105, an environment information acquisition unit 106, an environment information storage unit 107, A transmission data amount determination unit 108. Although not shown, each component is connected to a CPU or MPU (hereinafter referred to as a CPU or the like) built in the data transfer apparatus 10. The CPU or the like controls each component by executing a predetermined program stored in a ROM or a hard disk drive (not shown).

  The data acquisition unit 101 is connected to each device (for example, a solar cell, various sensors, a power conditioner, etc.) in photovoltaic power generation so that data communication can be performed by wire or wirelessly. Log data such as power generation amount and weather conditions transmitted from each device at a time interval). The data acquisition unit 101 stores the received log data in the buffer 102. The buffer 102 is composed of, for example, a readable / writable nonvolatile semiconductor memory.

  The wide area communication unit 103 is connected to a data communication apparatus 30 such as a modem, is connected to an AP (access point) 40 provided by an ISP (Internet Service Provider) via a telephone line, and is further connected via a wide area network N. Then, communication connection is made to the data collection server 20. The telephone line here is a wireless telephone line such as GSM (Global System for Mobile Communications), and the wide area communication unit 103 uses PPP (Point-to-Point Protocol) as a data link layer protocol by dial-up. Connect to AP40.

  As shown in FIG. 2, the wide area communication unit 103 includes a communication control unit 110, a billing target connection execution unit 111, and a data communication execution unit 112. The data communication execution unit 112 includes communication software such as TCP / IP and HTTP client functions, and executes processing for transferring the log data acquired by the data acquisition unit 101 and stored in the buffer 102 to the data collection server 20. .

  The billing target connection execution unit 111 has a function of controlling the data communication device 30 by an AT command, a PPP communication function for connecting to the AP 40, and the like, and is related to communication with a telephone line provider and ISP, that is, billing. Perform communication connection and disconnection. The communication control unit 110 controls communication processing by the charge object connection execution unit 111 and the data communication execution unit 112 according to the processing result of the transmission data amount determination unit 108 described later.

  The line status acquisition unit 104 acquires data related to the line status (line status data) such as an error and the amount of transmission data that occurred while the wide area communication unit 103 is performing communication. In the present embodiment, the line status acquisition unit 104 divides and transmits the start time, transfer success / failure, the total number of bytes to be transferred (total number of bytes), and the entire data into a plurality of sessions. In this case, the number of divisions and the order of transmission (division), the scheduled transfer byte number, and the actual transfer byte number are acquired and stored in the line state storage unit 105 as line state data (see FIG. 3).

  The line state storage unit 105 is configured by, for example, a readable / writable nonvolatile semiconductor memory. As shown in FIG. 3, line state data for the past several hours is accumulated and stored in the line state storage unit 105.

  The environment information acquisition unit 106 acquires various information related to the current weather condition from each measuring instrument (not shown) as environment information. In the present embodiment, the environment information acquisition unit 106 acquires, as environment information, a weather state that is generally considered to affect the line state, that is, weather, temperature, relative humidity, water vapor density, atmospheric pressure, and the like. The environmental information acquisition unit 106 is based on data acquired from various measuring instruments (not shown) (for example, a visibility meter, a sunshine meter, a thermometer, a hygrometer, a barometer, etc.) connected to the data transfer device 10 for these weather conditions. To decide. If the log data received by the data acquisition unit 101 includes information on weather conditions, the environment information acquisition unit 106 may extract and use the information from the log data, or You may make it the specification which downloads the information regarding a weather condition from the collection server 20. FIG.

  The environment information acquisition unit 106 acquires the above environment information every predetermined time, and stores it in the environment information storage unit 107 composed of, for example, a readable / writable nonvolatile semiconductor memory (see FIG. 4).

  Based on the line state data stored in the line state storage unit 105, the environment information stored in the environment information storage unit 107, and the total number of bytes, the transmission data amount determination unit 108 performs a session (HTTP session). ) Calculates the amount of data (number of bytes) that can be transmitted without being disconnected.

  Subsequently, a procedure of processing executed by the data transfer apparatus 10 configured as described above will be described with reference to flowcharts of FIGS. 5 and 6.

  When the power of the data transfer device 10 is turned on, the CPU or the like is activated, and a predetermined program stored in a ROM or a hard disk drive (both not shown) is executed, so that the following processing is repeated. Is called. First, the data acquisition unit 101 executes processing for acquiring log data from another device (step S101 in FIG. 5).

  For example, the data acquisition unit 101 issues a log data transmission request message to all the devices to be connected (for example, a solar cell, various sensors, a power conditioner, and the like). In response to the transmission request message, each device transmits log data held by each device to the data transfer device 10. The data acquisition unit 101 receives log data transmitted from each device and stores it in the buffer 102.

  In synchronization with the execution of the above process by the data acquisition unit 101, the environment information acquisition unit 106 executes a process of acquiring environment information (step S102). The environment information acquisition unit 106 acquires data (measured values) from each measuring instrument (for example, a visibility meter, a sunshine meter, a thermometer, a hygrometer, a barometer, etc.) not shown, and based on these, current weather conditions That is, the weather, temperature, relative humidity, water vapor density, and atmospheric pressure are obtained. Then, the obtained weather condition is stored in the environment information storage unit 107 as environment information. The environment information acquisition unit 106 may execute the environment information acquisition process asynchronously with the process by the data acquisition unit 101, that is, at different time intervals.

  Next, the CPU or the like determines whether there is data (transmission data) to be transmitted to the data collection server 20, that is, whether there is untransmitted log data in the buffer 102 (step S103). If there is transmission data (YES in step S103), data transmission processing is executed (step S104). On the other hand, if there is no transmission data (NO in step S103), the process proceeds to step S105.

  Here, the data transmission processing will be described in detail with reference to the flowchart of FIG. First, the billing target connection execution unit 111 executes dial-up connection (step S201). The dial-up connection is established by telephone line connection by operating the data communication device 30 with an AT command and establishment of a PPP connection with the AP 40 by the PPP protocol. In the present embodiment, the fee required for communication is charged according to the usage time of the telephone line and the connection time of PPP.

  Next, the transmission data amount determination unit 108 includes the line state data stored in the line state storage unit 105, the environment information stored in the environment information storage unit 107, and the log data stored in the buffer 102. Based on the total amount (that is, the total number of bytes), a data amount (scheduled transfer byte number) that can be transmitted in one session is calculated and determined (step S202). A specific example of this calculation method is shown below.

(1) Calculation method based on line status data (transfer success / failure, actual transfer byte count) and total byte count In this calculation method, the transmission data amount determination unit 108 performs transfer according to the success / failure of the previous transfer. Determine the planned number of bytes. Regardless of the success or failure of the previous transfer, if the current total number of bytes is less than or equal to the previous transfer actual number of bytes, the transmission data amount determination unit 108 stores the entire data to be transferred (that is, stored in the buffer 102). The number of bytes of all log data) is determined as the number of bytes to be transferred this time.

  If the current total number of bytes exceeds the previous transfer actual number of bytes, and the previous transfer is successful, the transmission data amount determination unit 108 must not be less than the previous transfer actual number of bytes. As a condition, a value (number of bytes) obtained by dividing the total number of bytes by n (n is an integer equal to or greater than 1) is determined as the current scheduled transfer number of bytes.

  On the other hand, if the current total number of bytes exceeds the previous transfer actual number of bytes and the previous transfer has failed, the transmission data amount determination unit 108 sets the total number of bytes to n (n is If the value is less than or equal to the previous transfer actual number of bytes, the value is determined as the current transfer scheduled byte number.

  For example, in FIG. 3, in the session indicated by the record of number 1, data transfer has been successful, and the transfer result byte number is 204,800 bytes. In the subsequent session, that is, the session indicated by the record of number 2, the total number of bytes is 307,200 bytes. Accordingly, when applied to the above calculation method, the number of bytes scheduled to be transferred in this session is 307,200 bytes.

  In the session indicated by the record with the number 2, data transfer has failed, and the actual transfer byte count is 285,000 bytes. In this case, it is necessary to retransmit the data of the total number of bytes (307,200 bytes) in subsequent sessions. The transmission data amount determination unit 108 divides 307,200 bytes into n (n is an integer equal to or greater than 2) so that the scheduled transfer byte number is equal to or less than the previous transfer actual byte number (285,000 bytes). In this case, when divided into two, the data transfer amount in one session is 153,600 bytes, so the above calculation condition is cleared. Therefore, as indicated by the records of number 3 and number 4, 307,200 bytes of data are transmitted in two sessions of 153,600 bytes. If retransmission also fails, it is further divided and retransmitted.

  In the session indicated by the record with the number 5, the total number of bytes is 204,800 bytes. In the previous session (the session indicated by the record with the number 4), the data transfer was successful, and the transfer record The number of bytes is 153,600 bytes. In this case, when divided into two, the data transfer amount in one session is 102,400 bytes, which is less than 153,600 bytes. Therefore, the transmission data amount determination unit 108 determines 204,800 bytes, which is a value that is not divided (in other words, a value that is divided by 1), as the current transfer planned number of bytes.

(2) Calculation Method Based on Environmental Information In this calculation method, the transmission data amount determination unit 108 is a publicly known document such as “Radio Wave Propagation Handbook (Realize Science and Technology Center, 1999) Chapters 5 and 6”. Based on the information disclosed in the above, the attenuation rate of the radio wave is obtained by referring to the environment information stored in the environment information storage unit 107. The amount of data that can be transmitted in one session (transfer) using a predetermined calculation formula or table prepared in advance to derive the number of bytes estimated to be transferable from the obtained attenuation rate of radio waves Determine the planned number of bytes).

  As in the calculation example described above, the transmission data amount determination unit 108 may determine the number of bytes to be transferred by referring to only one of the line state data and the environment information, and depending on various conditions, It may be switched whether to refer to. For example, when the line state data is not stored in the line state storage unit 105 such as when the data transfer apparatus 10 is started up, the transmission data amount determination unit 108 stores the environment information stored in the environment information storage unit 107. The number of bytes scheduled for transfer may be calculated with reference to the reference.

  Alternatively, the amount of data (scheduled transfer bytes) that can be transmitted in one session, the smaller of the data amount determined by the calculation method of (1) and the data amount determined by the calculation method of (2) Number).

  Returning to the flowchart of FIG. 6, in step S203, the data communication execution unit 112 establishes a session for data transfer (HTTP session). After the session is established, the data communication execution unit 112 executes data transfer by using an HTTP PUT method or the like (step S204). After the data transfer ends, the data communication execution unit 112 disconnects the session (step S205).

  When establishing and disconnecting a session, for example, when the connection and disconnection of a TCP connection is required for each HTTP session as in HTTP 1.0, the data communication execution unit 112 establishes a TCP connection in step S203. In step S205, the TCP connection is disconnected.

  In addition, as in HTTP 1.1, when the communication by the HTTP session is possible a plurality of times while the TCP connection is continued, the data communication execution unit 112 establishes / disconnects the TCP connection for each HTTP session. Without executing, the TCP connection can be established at the time of dial-up connection in step S201, and the TCP connection can be disconnected at the time of dial-up disconnection in step S210.

  The line state acquisition unit 104 acquires line state data in the session and records it in the line state storage unit 105 (step S206).

  If the data transfer in the session has succeeded (YES in step S207), the CPU or the like determines whether transmission of all data to be transmitted has been completed (step S209). As a result, when transmission of all data is completed (YES in step S209), the billing object connection execution unit 111 executes dial-up disconnection (step S210). And CPU etc. complete | finish this process (data transmission process).

  On the other hand, if transmission of all data has not been completed (NO in step S209), the process returns to step S203, and the above-described processing is repeated.

  When data transfer in the session has failed (NO in step S207), the CPU or the like determines whether or not the number of data transfer failures exceeds a predetermined number of times (step S208). If the predetermined number of times is exceeded (YES in step S208), the CPU or the like determines that the line state is bad. In this case, since it is desirable to wait for the line state to recover, the CPU or the like causes the charge target connection execution unit 111 to execute dial-up disconnection (step S210), and ends this processing (data transmission processing).

  On the other hand, if the number of failures is less than or equal to the predetermined number (NO in step S208), the process returns to step S203, and the above-described processing is repeated.

  When the above data transmission processing is completed, the CPU or the like temporarily waits for processing by each component until a predetermined time elapses (step S105 in FIG. 5). Thereafter, the CPU or the like activates the data acquisition unit 101, and thereafter, the processing from step S101 is repeated.

  As described above, in the data transfer system according to the present embodiment, in the data transfer device 10, when the data (log data) acquired by the data acquisition unit 101 is transmitted to the data collection server 20, the data is stored in the line state storage unit 105. Based on the stored line state data, the transmission data amount determination unit 108 determines the amount of data (scheduled transfer byte number) that can be transmitted in one session. Then, the wide area communication unit 103 divides and transfers all data to be transmitted into a plurality of sessions as necessary based on the determined number of bytes to be transferred.

  For example, when the transfer in the previous session fails, the transmission data amount determination unit 108 sets the upper limit of the data amount to be transmitted in the current session as the transfer result byte of the previous session stored in the line state storage unit 105. Decide on a number below.

  This makes it possible to prevent a large amount of data from being transmitted at a time if the line condition is bad, and even if the session is disconnected during the process, it is possible to prevent the retransmission of a large amount of data. become. In particular, when the line usage fee is a pay-per-use system according to the connection time, an increase in the line usage fee can be effectively prevented.

  Further, for example, when the transfer in the previous session is successful, the transmission data amount determination unit 108 transfers the upper limit of the data amount transmitted in the current session to the transfer of the previous session stored in the line state storage unit 105. Decide not to fall below the actual number of bytes.

  As a result, when the line state is restored, the amount of data transferred in one session can be increased, overhead due to dividing and transferring data can be reduced, and communication time can be shortened.

  In addition, if the line status is very bad, such as when data transfer fails a predetermined number of times, the chargeable communication may be disconnected even if the transfer of all data to be transferred has not been completed. it can. This can prevent an unnecessary increase in the line usage fee.

  In addition, the transmission data amount determination unit 108 refers to the environmental information such as the weather condition acquired by the environmental information acquisition unit 106 and stored in the environmental information storage unit 107, and the amount of data that can be transmitted in one session ( The number of bytes to be transferred) can also be determined. Thereby, the state of the line can be grasped without using the line, and the chance of using the line when the line state is bad can be reduced. Further, by using the line state data and the environment information in combination, it is possible to expect an improvement in the accuracy of the number of bytes to be transferred determined by the transmission data amount determination unit 108.

  In the above case, the data transfer apparatus 10 may download the environment information from the data collection server 20 and obtain it. In this way, in the case of a system configuration in which a plurality of data transfer apparatuses 10 are connected to one data collection server 20 via the wide area network N, only a measuring instrument or the like for detecting the weather condition is installed in the data collection server 20. Therefore, it is possible to reduce the cost of the entire system.

  Further, when the environment information is included in the log data received by the data acquisition unit 101 from another device, the environment information acquisition unit 106 extracts the environment information from the log data received by the data acquisition unit 101, You may make it utilize this. In this way, neither the data transfer apparatus 10 nor the data collection server 20 need to install a measuring instrument or the like for detecting the weather condition, and further cost reduction can be expected.

  In addition, this invention is not limited to the said embodiment, Of course, the various change in the range which does not deviate from the summary of this invention is possible.

  For example, the data communication device 30 may be included in the wide area communication unit 103 of the data transfer device 10.

  Further, in the specification in which the transmission data amount determination unit 108 refers to only one of the line state data and the environment information to determine the transfer byte count, the data transfer device 10 naturally processes the other process. It is not always necessary to provide the functional units (environment information acquisition unit 106 and environment information storage unit 107 or line state acquisition unit 104 and line state storage unit 105) according to the above.

  Further, the function of each component in the data transfer apparatus 10 of the above embodiment may be realized by a CPU or the like executing a predetermined program. By applying such a program, it is possible to cause an existing personal computer (PC) or the like to function as the data transfer apparatus according to the present invention.

  Such a program distribution method is arbitrary, for example, a computer-readable recording medium such as a CD-ROM (Compact Disk Read-Only Memory), a DVD (Digital Versatile Disk), an MO (Magneto Optical Disk), or a memory card. It may be stored and distributed in a network, or distributed via a communication network such as the Internet.

  The present invention can be suitably applied to a system that acquires log data such as the amount of power generation at each time from each device constituting the solar power generation system and transfers the log data to a server.

10 Data Transfer Device 20 Data Collection Server 30 Data Communication Device 40 AP (Access Point)
DESCRIPTION OF SYMBOLS 101 Data acquisition part 102 Buffer 103 Wide area communication part 104 Line state acquisition part 105 Line state storage part 106 Environmental information acquisition part 107 Environment information storage part 108 Transmission data amount determination part

Claims (13)

Data acquisition means for acquiring data from other devices and storing the data in a buffer;
Communication means for transmitting data stored in the buffer to a server connected via a predetermined network;
Line state acquisition means for acquiring line state data relating to the line state;
Line state storage means for accumulating and storing the line state data acquired by the line state acquisition means;
Based on the line state data stored in the line state storage means and the total amount of data stored in the buffer, the amount of data that can be transmitted in one session with the server can be transmitted. A transmission data amount determining means for determining a data amount;
It said communication means, if the total amount of data stored in the buffer is greater than the transmittable data amount, and transmits the data stored in the buffer is divided into at least two or more sessions,
The line state data stored in the line state storage means includes the amount of data transferred in the previous session,
The transmission data amount determining means determines the transmittable data amount based on the data transfer amount in the previous session and the success or failure of the data transfer in the previous session.
A data transfer device.   2. The data transfer apparatus according to claim 1, wherein the communication unit includes a billing target connection executing unit for connecting and disconnecting billing target communication. Prior Symbol transmission data amount determining means,
When the data transfer in the previous session fails, the upper limit of the transmittable data amount is determined to be a value equal to or less than the data transfer amount in the previous session,
When the data transfer in the previous session is successful, the upper limit of the transmittable data amount is determined to be a value equal to or greater than the data transfer amount in the previous session.
The data transfer device according to claim 1, wherein the data transfer device is a data transfer device. Environmental information acquisition means for acquiring current environmental information;
Environmental information storage means for storing the environmental information acquired by the environmental information acquisition means,
The transmission data amount determining means determines the transmittable data amount in consideration of the environment information stored in the environment information storage means.
The data transfer device according to claim 1, wherein the data transfer device is a data transfer device. The environmental information is information regarding current weather conditions.
The data transfer apparatus according to claim 4, wherein: The environmental information acquisition means extracts the environmental information from the data acquired by the data acquisition means;
6. The data transfer apparatus according to claim 4, wherein the data transfer apparatus is a data transfer apparatus. Data acquisition means for acquiring data from other devices and storing the data in a buffer;
Communication means for transmitting data stored in the buffer to a server connected via a predetermined network;
Environmental information acquisition means for acquiring environmental information which is information on the current weather condition ;
Environmental information storage means for storing the environmental information acquired by the environmental information acquisition means;
Transmission data amount determining means for determining a transmittable data amount that is a data amount that can be transmitted in one session with the server, based on the environment information stored in the environment information storage means,
It said communication means, if the total amount of data stored in the buffer is greater than the transmittable data amount, and transmits the data stored in the buffer is divided into at least two or more sessions,
The transmission data amount determining means refers to the environment information to determine a radio wave attenuation rate, and determines the transmittable data amount based on the calculated radio wave attenuation rate.
A data transfer device. Line state acquisition means for acquiring line state data relating to the line state;
Line state storage means for accumulating and storing the line state data acquired by the line state acquisition means,
The transmission data amount determining means includes
If the line status data is not stored in the line status storage means, based on the environment information, determine the amount of data that can be transmitted,
When the line state data is stored in the line state storage unit, the transmittable data amount is determined based on the line state data and the total amount of data stored in the buffer.
8. The data transfer apparatus according to claim 7, wherein A data acquisition step of acquiring data from another device and storing it in a buffer;
A communication step of transmitting data stored in the buffer to a server connected via a predetermined network;
A line state acquisition step of acquiring line state data relating to the state of the line and storing it in the line state storage means;
Transmittable data that is the amount of data that can be transmitted in one session with the server, based on the line state data stored in the line state storage means and the total amount of data stored in the buffer A transmission data amount determination step for determining the amount;
Wherein the communication step, when the total amount of data stored in the buffer is greater than the transmittable data amount, and transmits the data stored in the buffer is divided into at least two or more sessions,
The line state data stored in the line state storage means includes the amount of data transferred in the previous session,
In the transmission data amount determination step, the transmittable data amount is determined based on the data transfer amount in the previous session and the success or failure of the data transfer in the previous session.
A data transfer method characterized by the above. Computer
Data acquisition means for acquiring data from other devices and storing it in a buffer;
A communication means for transmitting data stored in the buffer to a server connected via a predetermined network;
Line state acquisition means for acquiring line state data relating to the line state and storing it in the line state storage means;
Based on the line state data stored in the line state storage means and the total amount of data stored in the buffer, transmission is possible that is the amount of data that can be transmitted in one session with the server Function as a transmission data amount determining means for determining the data amount,
It said communication means, if the total amount of data stored in the buffer is greater than the transmittable data amount, and transmits the data stored in the buffer is divided into at least two or more sessions,
The line state data stored in the line state storage means includes the amount of data transferred in the previous session,
The transmission data amount determining means determines the transmittable data amount based on the data transfer amount in the previous session and the success or failure of the data transfer in the previous session.
A program characterized by that. A data transfer system comprising one or more data transfer devices and a server connected to the one or more data transfer devices via a predetermined network so that they can communicate with each other.
The data transfer device
Data acquisition means for acquiring data from other devices and storing the data in a buffer;
Communication means for transmitting data stored in the buffer to the server;
Line state acquisition means for acquiring line state data relating to the line state;
Line state storage means for accumulating and storing the line state data acquired by the line state acquisition means;
Transmittable data that is the amount of data that can be transmitted in one session with the server based on the line state data stored in the line state storage means and the total amount of data stored in the buffer A transmission data amount determining means for determining the amount,
It said communication means, if the total amount of data stored in the buffer is greater than the transmittable data amount, and transmits the data stored in the buffer is divided into at least two or more sessions,
The line state data stored in the line state storage means includes the amount of data transferred in the previous session,
The transmission data amount determining means determines the transmittable data amount based on the data transfer amount in the previous session and the success or failure of the data transfer in the previous session.
A data transfer system characterized by that. The data transfer device
Environmental information acquisition means for acquiring current environmental information;
Environmental information storage means for storing the environmental information acquired by the environmental information acquisition means,
The transmission data amount determining means determines the transmittable data amount in consideration of the environment information stored in the environment information storage means.
The data transfer system according to claim 11. The server transmits data including the environment information to the data transfer device;
The environment information acquisition means acquires data transmitted from the server via the communication means, and extracts the environment information from the acquired data.
The data transfer system according to claim 12.

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