Abstract:
Information regarding moving bodies ( 00 ) that are in danger of colliding is collected at an appropriate frequency in accordance with the degree of danger. This information-collecting device has a risk calculation means and a transmission-interval determination means. The risk calculation means receives, from a plurality of moving bodies, state information that includes locations and velocities and is transmitted at provided time intervals. The risk calculation means also computes the distance between and relative velocities of two moving bodies. The transmission-interval determination means computes an interval such that the higher the relative velocities of two moving bodies are relative to the distance therebetween, the shorter the interval is, and provides the computed interval to said moving bodies.

Description:
TECHNICAL FIELD 
       [0001]    The present invention relates to an information-collecting device, an information-collecting method, and a program-recording medium, in particular, an information-collecting device, an information-collecting method, and a program-recording medium that collect information of a moving body such as a vehicle, a ship, or an airplane. 
       BACKGROUND ART 
       [0002]    There is a system in which “information” created from a number of vehicles is collected via a “network” to be utilized. A sudden braking notification system is an example of such a system. The sudden braking notification is a service of notifying a plurality of vehicles existing behind a vehicle that brakes hard suddenly of occurrence of sudden braking. 
         [0003]    The sudden braking notification system frequently collects information of a speed and a position of a vehicle so as to detect sudden braking in real time and accurately grasp an anteroposterior relationship of vehicles. In addition, there is a system in which information is collected from a number of airplanes or ships so as to achieve safe traffic. If these systems constantly collect a large amount of information, a large load is applied to the network. As a technology to control the load, the following technologies are disclosed. 
         [0004]    PTL 1 discloses a vehicle that regularly transmits data to surrounding other vehicles while changing transmission power, that is, a communication distance. Accordingly, the vehicle transmits data to a nearby vehicle frequently and to a distant vehicle less frequently. 
         [0005]    PTL 2 discloses a vehicle that transmits driving information of the own vehicle to vehicles that drive in the surrounding area. The vehicle determines a transmission frequency depending on a driving place of the own vehicle. 
         [0006]    PTL 3 discloses a system in which a usage communication fee is calculated and a transmission interval is changed depending on a determination result whether or not to exceed a threshold value of the communication fee specified in advance. 
       CITATION LIST 
     Patent Literature 
       [0000]    
       
         [PTL 1] JP 2010-183178 A 
         [PTL 2] JP 2009-3822 A 
         [PTL 3] JP 2005-72854 A 
       
     
       SUMMARY OF INVENTION 
     Technical Problem 
       [0010]    The vehicle of PTL 1 controls a transmission frequency of data depending on a distance from another vehicle. The vehicle of PTL 2 controls a transmission frequency of data depending on a position of the vehicle. The system of PTL 3 controls a communication frequency depending on the communication fee. These technologies cannot control a communication frequency appropriately depending on a risk of a collision of a moving body, such as a vehicle, a ship, or an airplane. For example, the vehicle of PTL 1 cannot control a communication frequency appropriately with respect to two vehicles moving close to each other or two vehicles moving away from each other. The two vehicles moving close to each other are at high risk of a collision, however, the two vehicles moving away from each other are not at high risk of a collision. 
         [0011]    An object of the present invention is to solve the above-described problem and provide an information-collecting device, an information-collecting method, and a program that collect information at an appropriate frequency. 
       Solution to Problem 
       [0012]    An information-collecting device according to one aspect of the present invention includes: a risk calculation means that receives state information including a position and a speed from a plurality of moving bodies that transmit the state information at a notified time interval, and calculates a distance and a relative speed between two moving bodies; and a transmission-interval determination means that calculates an interval that is shortened depending on a magnitude of the relative speed with respect to the distance, and notifies the calculated interval to the two moving bodies. 
         [0013]    An information-collecting method according to another aspect of the present invention includes: receiving state information including a position and a speed from a plurality of moving bodies that transmit the state information at a notified time interval, and calculating a distance and a relative speed between two moving bodies; and calculating an interval that is shortened depending on a magnitude of the relative speed with respect to the distance, and notifying the calculated interval to the two moving bodies. 
       Advantageous Effects of Invention 
       [0014]    An information-collecting device according to the present invention can collect information of a moving body at an appropriate frequency. 
     
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         [0015]      FIG. 1  illustrates a configuration of an information-collecting system  90  according to a first exemplary embodiment of the present invention. 
           [0016]      FIG. 2  illustrates a configuration of sensor data  20  that a risk calculation unit  11  receives as input from a communication unit  05 . 
           [0017]      FIG. 3  illustrates a configuration of transmission-interval calculation data  40  that the risk calculation unit  11  outputs to a transmission-interval determination unit  12 . 
           [0018]      FIG. 4  illustrates a configuration of band data  30  that a band acquisition unit  13  stores. 
           [0019]      FIG. 5  is an operation flowchart of the information-collecting system  90 . 
           [0020]      FIG. 6  is a configuration diagram of an information-collecting device  10  according to a second exemplary embodiment. 
       
    
    
     DESCRIPTION OF EMBODIMENTS 
     First Exemplary Embodiment 
     (Description of Configuration) 
       [0021]    Exemplary embodiments will be described in detail with reference to the drawings. 
         [0022]      FIG. 1  illustrates a configuration of an information-collecting system  90  according to a first exemplary embodiment of the present invention. Referring to  FIG. 1 , the information-collecting system  90  includes a plurality of moving bodies  00  and at least one information-collecting device  10  connected to them by a wireless communication network. The moving bodies  00  are, for example, vehicles including automobiles and trains, airplanes, or ships. 
         [0023]    The information-collecting device  10  includes a risk calculation unit  11 , a transmission-interval determination unit  12 , and a band acquisition unit  13 . The information-collecting device  10  is a device that performs processing, such as sudden braking notification, using data transmitted from the moving body  00 . Thus, the information-collecting device  10  includes a part that performs the processing. However, the part is omitted in the present drawing. 
         [0024]    The moving body  00  includes a sensor  04  and a communication unit  05 . 
         [0025]    The risk calculation unit  11  of the information-collecting device  10  receives state information of the plurality of moving bodies  00 , which varies from hour to hour, as input from the communication unit  05  of the moving body  00 . For example, the risk calculation unit  11  stores the input as a history in a memory (not illustrated) of the information-collecting device  10 . Furthermore, the risk calculation unit  11  calculates a risk  44  from the input and the history, and outputs a state of the moving body  00  including the risk  44  to the transmission-interval determination unit  12 . The risk  44  is, for example, an index indicating a collision possibility between the moving body  00  and another moving body  00 . For example, the risk  44  becomes larger as the collision possibility is increased. However, this is merely an example, and an expression of the risk  44  is not limited thereto. 
         [0026]      FIG. 2  illustrates a configuration of sensor data  20  that is the state information that the risk calculation unit  11  receives as the input from the communication unit  05 . The sensor data  20  includes a moving body ID  21  (IDentification), a base station ID  22 , a time  23 , a position  24 , and a speed  25 . 
         [0027]    The moving body ID  21  represents an ID that identifies the moving body  00 . The base station ID  22  represents an ID of a base station that the moving body  00  uses for communication. The time  23  represents a time when the sensor  04  records the position  24  and the speed  25 . The position  24  represents a position of the moving body  00 , for example, longitude and latitude. When the moving body  00  is an airplane, the position  24  may include an altitude. The speed  25  represents a moving speed of the moving body  00 . 
         [0028]    The sensor data  20  includes a data item for performing the processing, such as sudden braking notification, but the data item is omitted in the present drawing. 
         [0029]    For example, when “a vehicle having an ID of  001  communicates with a base station A, and runs at a speed of 60 km/h at a position of longitude 135.0000 and latitude 35.0000 at a time of 2013-05-30 12:00:05”, the sensor data  20  becomes the data illustrated in  FIG. 2 . More specifically, the sensor data  20  becomes the data “ 001 ”, “A”, “2013-05-30 12:00:05”, “(135.0000, 35.0000)”, “60”, which is obtained by sequentially connecting values of “the moving body ID  21 ”, “the base station ID  22 ”, “the time  23 ”, “the position  24 ”, and “the speed  25 ”. 
         [0030]      FIG. 3  illustrates a configuration of transmission-interval calculation data  40  that the risk calculation unit  11  outputs to the transmission-interval determination unit  12 . The transmission-interval calculation data  40  includes a moving body ID  41 , a base station ID  42 , a time  43 , and the risk  44 .  FIG. 3  exemplifies two pieces of the transmission-interval calculation data  40  created with respect to the moving bodies  00  whose moving body IDs  41  are  001  and  002 . 
         [0031]    A calculation method of the risk  44 , which the risk calculation unit  11  performs will be described. The risk calculation unit  11  calculates a distance and a relative speed between two moving bodies  00  from two pieces of the sensor data  20  received from the two moving bodies  00 , and calculates the risk  44  from the distance between vehicles and the relative speed. 
         [0032]    When receiving new sensor data  20  from a certain moving body  00 , for example, a moving body A, the risk calculation unit  11  extracts a moving body  00  that travels in the same direction along the same route as the moving body A. The risk calculation unit  11  performs the extraction from a trajectory of the moving body  00  and stored positional information of the route, for example. The risk calculation unit  11  determines the trajectory of the moving body  00  from the time  23  and the position  24  of the sensor data  20  in the history, for example. Here, the route is, for example, a road, a railroad, a sea route, or an air route. 
         [0033]    When the route and the traveling direction can be determined from only the position  24 , the positional information of the route is unnecessary. For example, there is a case where an identifier and section numbers that continuously increase or decrease from a starting point to an ending point are assigned to each route, and transmitters each of which transmits the identifier of the route and the section number are placed along the route at regular intervals. In such a situation, when a combination of the identifier of the route and the section number that the moving body  00  has received is the position  24 , road information is unnecessary for the determination. More specifically, the risk calculation unit  11  can determine the route from the route identifier included in the position  24 , and the traveling direction in which the moving body moves from a temporal change of the section number. 
         [0034]    It is to be noted that, as a given condition, when it is known that the moving body  00  to be targeted travels in the same direction along the same road, railroad, railroad, the extraction itself is unnecessary. 
         [0035]    Next, the risk calculation unit  11  narrows down the sensor data  20  that another moving body  00  that is in the vicinity of the moving body A and is coming close to the moving body A has transmitted, from the extracted history. A narrowing-down condition is, for example, the latest data of a moving body  00  in which differences in the time  23  and the position  24  are within certain ranges, the moving body ID  21  is different, and a distance from the moving body A is reduced. The risk calculation unit  11  determines from the position  24  and the speed  25  whether the distance from the moving body A is reduced. More specifically, the risk calculation unit  11  determines whether the distance from the moving body A is reduced depending on whether the speed  25  of a moving body  00  behind in the traveling direction is faster than that of a moving body  00  in front. 
         [0036]    It is to be noted that, when a plurality of pieces of the sensor data  20  are extracted from the history after performing the narrowing-down, the risk calculation unit  11  may select one piece of the sensor data  20 . For example, the risk calculation unit  11  selects the sensor data  20  of the moving body  00  that is the closest to the moving body A. 
         [0037]    The risk calculation unit  11  calculates a distance between the two moving bodies  00  from a difference in the position  24  between two pieces of the sensor data  20 , the sensor data  20  of the moving body A and the narrowed-down sensor data  20 . In addition, the risk calculation unit  11  calculates a difference in the speed  25  between the two pieces of the sensor data  20  as a relative speed. Furthermore, the risk calculation unit  11  calculates the risk  44  by dividing the calculated relative speed by the distance between vehicles and determining an absolute value, and outputs the risk  44  to the transmission-interval determination unit  12  as the transmission-interval calculation data  40 . However, the calculation method is merely an example, and the calculation method of the risk  44  is not limited thereto. 
         [0038]    The risk calculation unit  11  creates one piece of the transmission-interval calculation data  40  with respect to the sensor data  20  of the moving body A, and creates another piece of the transmission-interval calculation data  40  with respect to the sensor data  20  extracted from the history. The moving body ID  41 , the base station ID  42 , and the time  43  of the transmission-interval calculation data  40  are copied from the moving body ID  21 , the base station ID  22 , and the time  23  of each sensor data  20 . 
         [0039]    When there are a plurality of (m) pieces of the sensor data  20  extracted from the history, the risk calculation unit  11  may calculate the risk  44  between the sensor data  20  of the moving body A and each of the extracted m pieces of the sensor data  20 . After that, the risk calculation unit  11  creates one piece of the transmission-interval calculation data  40  with respect to the sensor data  20  of the moving body A, and creates one piece of the transmission-interval calculation data  40  with respect to each of the m pieces of the sensor data  20  extracted from the history. In this case, the risk calculation unit  11  sets, for example, the maximum value among the m risks  44  in the transmission-interval calculation data  40  created with respect to the sensor data  20  of the moving body A. 
         [0040]    A concrete description will be given using a numerical example. When the inputted sensor data  20  is the one exemplified in  FIG. 2 , the risk calculation unit  11  searches from the history the latest sensor data  20  of a moving body  00  within a distance of 100 m depending on the position  24  (135.0000, 35.0000) to extract the position  24  and the speed  25 . The risk calculation unit  11  extracts from the history, for example, the sensor data  20  in which the moving body ID  21  is  002 , the position  24  is (135.0000, 35.0002), and the speed  25  is 55 km/h, and performs calculation, so that the distance between vehicles is about 22 m and the relative speed is 60−55=5 (km/h). Furthermore, the risk calculation unit  11  divides the calculated relative speed by the distance between vehicles to obtain 5/22≈0.23, and this is assumed as the risks  44  of the moving bodies  001 ,  002 .  FIG. 3  exemplifies the two pieces of the transmission-interval calculation data  40  created here. 
         [0041]    The band acquisition unit  13  outputs a usage state of a communication band that the moving body  00  uses to the transmission-interval determination unit  12 . In concrete terms, the band acquisition unit  13  obtains the base station ID from the transmission-interval determination unit  12 , and outputs an available band (bps: bit per second) of the base station. 
         [0042]    The base station is an existing device. The band acquisition unit  13  stores a log regarding data indicating a maximum communication band of the base station and current communication, and calculates and stores in the memory (not illustrated) of the information-collecting device  10  the current available band of each base station. The band acquisition unit  13  may store the maximum communication band of the base station. 
         [0043]      FIG. 4  illustrates a configuration of band data  30  that the band acquisition unit  13  stores. The band data  30  includes a base station ID  31  and a current available band  32 . The band acquisition unit  13  filters the band data  30  by the base station ID received as the input, and outputs the available band  32  regarding the base station of the base station ID. The band acquisition unit  13  may acquire the available band of the base station from the base station or a management server device of a carrier, for example. 
         [0044]    For example, as illustrated in the example of  FIG. 4 , “when an available band of a base station having an ID of A is 128 bps”, the band acquisition unit  13  may perform output in the form of “the base station ID  31 ” and “the available band  32 ”. In this example, the output is a value of “A” and “128”. 
         [0045]    The transmission-interval determination unit  12  receives the transmission-interval calculation data  40  as input from the risk calculation unit  11 , and stores the transmission-interval calculation data  40  as a history in the memory (not illustrated) of the information-collecting device  10 . Furthermore, the transmission-interval determination unit  12  calculates, from each transmission-interval calculation data  40 , a transmission interval whose value becomes smaller as the risk  44  becomes higher, with respect to the moving body  00  of the moving body ID  41 , and outputs the transmission interval to the moving body  00 . It is to be noted that the transmission-interval determination unit  12  does not always have to take a history of the transmission-interval calculation data  40 . 
         [0046]    In addition, the transmission-interval determination unit  12  acquires base station information from the band acquisition unit  13  using the inputted base station ID  42 . In concrete terms, the transmission-interval determination unit  12  outputs “the base station ID”=“A” to the band acquisition unit  13 , and receives the available band  32  as input. 
         [0047]    When taking a history, the transmission-interval determination unit  12  searches the history by the inputted moving body ID  41 , and the searched transmission-interval calculation data  40  is overwritten by the inputted transmission-interval calculation data  40 . When the inputted moving body ID  41  does not exist in the history, the inputted transmission-interval calculation data  40  is added to the history as a new record. 
         [0048]    A transmission interval calculation method that the transmission-interval determination unit  12  performs will be described. The transmission-interval determination unit  12  calculates from the available band  32  of the base station and the size of the sensor data  20 , a minimum transmission interval within a range not exceeding the band. Furthermore, the transmission-interval determination unit  12  calculates a transmission interval according to the risk  44 . 
         [0049]    In concrete terms, the transmission-interval determination unit  12  divides the size of the sensor data  20  that the moving body  00  transmits by the current available band  32  obtained from the band acquisition unit  13 , and this value is assumed as a minimum value of the transmission interval. 
         [0050]    When the maximum available band  32  is obtained from the band acquisition unit  13 , the transmission-interval determination unit  12  divides a product of the size of the sensor data  20  and the number of the moving bodies  00  that use the same base station by the value of the available band  32  obtained from the band acquisition unit  13 , and this value is assumed as the minimum value of the transmission interval. The transmission-interval determination unit  12  obtains from the history within a past certain time of the sensor data  20  that the risk calculation unit  11  acquires, the number of the moving bodies  00  that use the same base station by counting the number of the moving body IDs  21 , which is different in each base station ID  22 . Alternatively, the transmission-interval determination unit  12  may obtain the number from a fixed value given as a parameter. This value is, for example, an estimate value based on past statistics. 
         [0051]    In addition, the transmission-interval determination unit  12  calculates an inverse number of the risk  44  with respect to all pieces of the inputted transmission-interval calculation data  40 , and the value is transmitted to the moving body  00  of each of the moving body IDs  41 . However, when a standard value of the transmission interval is below the minimum value of the transmission interval, the transmission-interval determination unit  12  transmits the minimum value to the moving body  00 . The calculation method is merely an example, and the transmission interval calculation method is not limited thereto. 
         [0052]    For example, the transmission-interval determination unit  12  may calculate the transmission interval only from the risk without calculating the minimum value from the available band. In this case, the information-collecting device  10  does not have to include the band acquisition unit  13 . 
         [0053]    A concrete description will be given using a numerical example. When the inputted transmission-interval calculation data  40  shows the two pieces of data exemplified in  FIG. 3 , the transmission-interval determination unit  12  calculates an inverse number of the value of the risk 44, 0.23, 1/0.23≈4.3 (sec), and this is assumed as the standard value of the transmission interval. In addition, since the available band  32  of the base station A is 128 (bps) and the number of vehicles that use the base station A is two, if the size of the sensor data  20  that the moving body  00  transmits is 64 (bit), the transmission-interval determination unit  12  calculates 64 (bit)×2 (the number of the vehicles)/128 (bit)=1.0 (sec), and this is assumed as the minimum value of the transmission interval. 
         [0054]    Here, the risk calculation unit  11 , the transmission-interval determination unit  12 , and the band acquisition unit  13  are configured by logic circuits. They are stored in the memory (not illustrated) of the information-collecting device  10  that is a computer, and may be achieved by software that is executed by a processor (not illustrated) of the information-collecting device  10 . 
         [0055]    The sensor  04  of the moving body  00  outputs a state of the moving body  00 , which varies from hour to hour, to the communication unit  05 . The sensor  04  is a combination of a plurality of existing devices. For example, a GPS sensor  04  for acquiring a position and a speed sensor  04  for acquiring a speed are mounted on the moving body  00 , and each sensor  04  outputs each measurement value to the communication unit  05 . 
         [0056]    The communication unit  05  receives the state information of the moving body  00 , which varies from hour to hour, as input from the sensor  04 , stores the state of the moving body  00  as a history, detects a change in an operation of the moving body  00  from the state information of the moving body  00  and the history, and starts transmission of the sensor data  20 . At this time, the communication unit  05  creates the sensor data  20  based on the latest measurement value of the sensor  04 , and transmits the sensor data  20  to the risk calculation unit  11  of the information-collecting device  10  at a time interval stored in a memory (not illustrated) of the moving body  00 . The communication unit  05  creates the sensor data  20  to be transmitted by setting the stored ID of the own moving body  00  in the moving body ID  21 , an ID obtained from a base station with which the communication unit  05  currently communicates in the base station ID  22 , the measurement values obtained from the sensor  04  in the position  24  and the speed  25 . 
         [0057]    In addition, when receiving the time interval from the transmission-interval determination unit  12  of the information-collecting device  10 , the communication unit  05  replaces the value stored in the memory. 
         [0058]    Here, the communication unit  05  is configured by logic circuits. They are stored in a memory of a computer (not illustrated) mounted on the moving body  00  that is a computer, and may be achieved by software that is executed by a processor thereof. 
       (Description of Operation) 
       [0059]      FIG. 5  is an operation flowchart of the information-collecting system  90 . The operation flow of the information-collecting system  90  includes a flow  1  in which the moving body  00  acquires vehicle information and transmits the vehicle information to the information-collecting device  10 , and a flow  2  in which the information-collecting device  10  determines a transmission frequency from the vehicle information and the available band  32  of a network. 
         [0060]    In the flow  1 , a step  1  and a step  2  are repeatedly executed. The sensor  04  executes the step  1  of outputting a state of the moving body  00 , which varies from hour to hour, to the communication unit  05 . The communication unit  05  executes the step  2  of transmitting the state of the moving body  00 , which varies from hour to hour, at a transmission interval stored in the memory. 
         [0061]    In the flow  2 , a step  3 , a step  4 , a step  5 , a step  6  and a step  7  are sequentially executed. The flow  2  is started when the step  2  of the flow  1  is operated, and is finished when the execution of the step  7  is finished. 
         [0062]    The risk calculation unit  11  executes the step  003  of calculating the risk  44  from the state of the moving body  00 , which varies from hour to hour. The transmission-interval determination unit  12  executes the step  4  of inquiring the available band  32  of the base station from the base station ID  22  used for transmitting the state of the moving body  00 . In this step, the transmission-interval determination unit  12  performs inquiry to the band acquisition unit  13 . The band acquisition unit  13  executes the step  5  of outputting the available band  32  of the base station used for transmitting the state information of the moving body  00 . 
         [0063]    The transmission-interval determination unit  12  executes the step  6  of calculating the transmission interval of the moving body  00  from the risk  44  and the available band  32 . Furthermore, the transmission-interval determination unit  12  also executes the step  7  of transmitting the value of the transmission interval to the communication unit  05  of the moving body  00 . 
         [0064]    It is to be noted that the communication unit  05  of the moving body  00  executes the step  8  of storing the transmission interval received from the transmission-interval determination unit  12  in the memory. 
         [0065]    The information-collecting device  10  can collect information of the moving body  00  at risk for a collision at an appropriate frequency, depending on the risk  44  thereof. In addition, the information-collecting device  10  can determine the transmission interval that effectively uses a network band for each moving body  00 , depending on a peripheral situation such as a usage situation of a network. 
         [0066]    The first reason is that the risk calculation unit  11  calculates the risk  44  indicating the degree of the collision possibility from the sensor data  20  that two moving bodies  00  have transmitted, and the transmission-interval determination unit  12  calculates a short (long) data transmission interval depending on the highness (lowness) of the risk  44 . More specifically, the information-collecting device  10  frequently collects data from a moving body  00  of high risk. Rapid control for avoiding danger becomes possible. On the other hand, the information-collecting device  10  collects data less frequently from a moving body  00  of low risk. An increase in a network load can be suppressed. 
         [0067]    The second reason is that the transmission-interval determination unit  12  calculates a lower limit of the transmission interval due to the limitation of the available band  32  of a base station, and performs control such that the transmission interval of the moving body  00  is not below the lower limit. 
       Second Exemplary Embodiment 
       [0068]      FIG. 6  is a configuration diagram of the information-collecting device  10  according to the present exemplary embodiment. 
         [0069]    The information-collecting device  10  includes the risk calculation unit  11  and the transmission-interval determination unit  12 . The risk calculation unit  11  receives state information including a position and a speed from a plurality of moving bodies  00  that transmit the state information at a notified time interval, and calculates a distance and a relative speed between two moving bodies  00 . The transmission-interval determination unit  12  calculates an interval that is shortened depending on the magnitude of the relative speed with respect to the distance, and notifies the calculated interval to the two moving bodies  00 . 
         [0070]    The information-collecting device  10  can collect information of the moving body  00  at risk for a collision at an appropriate frequency, depending on the risk  44  thereof. In addition, the information-collecting device  10  can determine the transmission interval that effectively uses a network band for each moving body  00 , depending on a peripheral situation such as a usage situation of a network. 
         [0071]    The reason is that the risk calculation unit  11  calculates the risk  44  indicating the degree of the collision possibility from the sensor data  20  that two moving bodies  00  have transmitted, and the transmission-interval determination unit  12  calculates a short (long) data transmission interval depending on the highness (lowness) of the risk  44 . More specifically, the information-collecting device  10  frequently collects data from a moving body  00  of high risk. Rapid control for avoiding danger becomes possible. On the other hand, the information-collecting device  10  collects data less frequently from a moving body  00  of low risk. An increase in a network load can be suppressed. 
         [0072]    Although the present invention has been described with reference to the exemplary embodiments, the present invention is not limited to the above-described exemplary embodiments. Various modifications that a person skilled in the art can understand can be made to configurations and details of the present invention within the scope of the present invention. 
         [0073]    This application claims priority to Japanese Patent Application No. 2014-067356 filed on Mar. 28, 2014, the entire contents of which are incorporated herein. 
       REFERENCE SIGNS LIST 
       [0000]    
       
           00  moving body 
           04  sensor 
           05  communication unit 
           10  information-collecting device 
           11  risk calculation unit 
           12  transmission-interval determination unit 
           13  band acquisition unit 
           20  sensor data 
           21  moving body ID 
           22  base station ID 
           23  time 
           24  position 
           25  speed 
           30  band data 
           31  base station ID 
           32  available band 
           40  transmission-interval calculation data 
           41  moving body ID 
           42  base station ID 
           43  time 
           44  risk 
           90  information-collecting system