Abstract:
A first communication unit communicates with a first communication terminal device by using a first communication scheme. A second communication unit communicates with a second communication terminal device by using a second communication scheme capable of communication over a longer distance than the first communication scheme. A search instruction communicating unit communicates a search instruction to the second communication terminal device via the second communication unit, the search instruction including an identifier identifying a first communication terminal device, and instructing the second communication terminal device to search for the first communication terminal device by using the first communication scheme.

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     This application is based upon and claims the benefit of priority from the prior Japanese Patent Application No. 2015-047206, filed on Mar. 10, 2015, and the prior Japanese Patent Application No. 2015-047207, filed on Mar. 10, 2015, the entire contents of each of which are incorporated herein by reference. 
     BACKGROUND 
     1. Field of the Invention 
     The present invention relates to a communication terminal device, communication system, and communication method used by workers who undertake dangerous operations such as fire-fighting operations. 
     2. Description of the Related Art 
     A system is proposed in which a biosensor is worn by the body of a firefighter and biological information on the firefighter is transmitted wirelessly to a command center to monitor the safety of the firefighter on a real time basis. For example, a firefighter is determined to be in a dangerous state if the heart rate of the firefighter is abnormal. 
     Patent document 1 discloses a mobile terminal for an emergency rescue support system, wherein, when abnormality of the body of a user is detected by referring to a measurement of a biological information sensor, the mobile terminal originates an emergency call to nearby mobile terminals. 
     [patent document 1] JP2003-109160 
     If a worker is located in a place such as a scene of a fire where radio waves from a GPS satellite cannot reach, it may be possible to know that the worker is in a dangerous state by receiving biological information on the worker wirelessly but it is difficult to identify the location of the worker. It is therefore to determine which worker should be sent for a rescue. 
     SUMMARY 
     To address the aforementioned issue, a communication terminal device ( 10 ) according to an embodiment of the present invention comprises: a second communication unit ( 132 ) that communicates with a second communication terminal device ( 10 ) by using a second communication scheme capable of communication over a longer distance than a first communication scheme; and a search instruction communicating unit ( 118   a ) that communicates a search instruction to the second communication terminal device ( 10 ) via the second communication unit ( 132 ), the search instruction including an identifier identifying a first communication terminal device ( 10 ) that communicates by using the first communication scheme, and instructing the second communication terminal device ( 10 ) to search for the first communication terminal device ( 20 ) identified by the identifier by using the first communication scheme. 
     Another embodiment of the present invention also relates to a communication terminal device ( 10 ). The communication terminal device ( 10 ) comprises: a first communication unit ( 131 ) that communicates with a first communication terminal device ( 20 ) by using a first communication scheme; and a second communication unit ( 132 ) that communicates with a second communication terminal device ( 10 ) by using a second communication scheme capable of communication over a longer distance than the first communication scheme; and a searching unit ( 114 ) that searches for the first communication terminal device ( 20 ) via the first communication unit ( 131 ) upon acquiring a search instruction from the second communication terminal device ( 10 ) via the second communication unit ( 132 ), the search instruction including an identifier identifying the first communication terminal device ( 20 ), and instructing the communication terminal device hosting the searching unit to search for the first communication terminal device ( 20 ) identified by the identifier by using the first communication scheme. 
     Still another embodiment of the present invention relates to a communication system ( 1 ). The communication system ( 1 ) comprises a first communication terminal device ( 20 ), a second communication terminal device ( 10 ), and a management device ( 30 ), wherein the second communication terminal device ( 10 ) includes: a second communication unit ( 132 ) that communicates with the management device ( 30 ) by using a second communication scheme capable of communication over a longer distance than a first communication scheme. The management device ( 30 ) includes: a communication unit ( 331 ) that communicates by using the second communication scheme, and a search instruction communicating unit ( 316 ) that communicates, in response to a trigger signal from the second communication terminal device ( 10 ) via the communication unit ( 331 ), a search instruction to another second communication terminal device ( 10 ) via the communication unit ( 331 ), the search instruction including an identifier identifying the first communication terminal device ( 20 ) that communicates by using the first communication scheme, and instructing the other second communication terminal device to search for the first communication terminal device ( 20 ) identified by the identifier by using the first communication scheme. 
     Still another embodiment of the present invention relates to a communication method. The method comprises: communicating a search instruction to a second communication terminal device ( 10 ) by using a second communication scheme capable of communication over a longer distance than a first communication scheme, the search instruction including an identifier identifying a first communication terminal device ( 20 ) that communicates by using the first communication scheme, and instructing the second communication terminal device to search for the first communication terminal device ( 20 ) identified by the identifier by using the first communication scheme. 
     Still another embodiment of the present invention also relates to a communication method. The method is adapted to a communication system ( 1 ) including a first communication terminal device ( 20 ), a second communication terminal device ( 10 ), and a management device ( 30 ), the method comprising: using the second communication terminal device ( 10 ) to communicate with the management device ( 30 ) by using a second communication scheme capable of communication over a longer distance than a first communication scheme. The method further comprises: using the management device ( 30 ) to communicate by using the second communication scheme, the management device ( 30 ) comprising: a search instruction communicating unit ( 316 ) that communicates, in response to a trigger signal from the second communication terminal device ( 10 ) by using the second communication scheme, a search instruction to another second communication terminal device ( 10 ) by using the second communication scheme, the search instruction including an identifier identifying the first communication terminal device ( 20 ) that communicates by using the first communication scheme, and instructing the other second communication terminal device to search for the first communication terminal device ( 20 ) identified by the identifier by using the first communication scheme. 
     Still another embodiment of the present invention relates to a communication terminal device ( 10 ). The communication terminal device ( 10 ) comprises: a first communication unit ( 131 ) that communicates with a first communication terminal device ( 20 ) by using a first communication scheme; and a storage unit ( 12 ) that stores identifier mapping information that maps a first identifier identifying the first communication terminal device ( 20 ) to a second identifier identifying a second communication terminal device ( 10 ) that communicates by using a second communication scheme capable of communication over a longer distance than the first communication scheme; a searching unit ( 114 ) that searches for the first communication terminal device ( 20 ) via the first communication unit ( 131 ) and acquires the first identifier of the first communication terminal device ( 20 ) detected by the search; and a communication destination determination unit ( 116 ) that acquires the second identifier mapped to the first identifier acquired by the searching unit ( 114 ), by referring to the identifier mapping information stored in the storage unit ( 12 ). 
     Still another embodiment of the present invention relates to a communication system ( 1 ). The communication system ( 1 ) comprises a first communication terminal device ( 20 ) identified by a first identifier, a second communication terminal device ( 10 ) identified by a second identifier, and a management device ( 30 ), wherein the first communication terminal device ( 20 ) includes a communication unit ( 231 ) that communicates with the second communication terminal device ( 10 ) by using a first communication scheme. The second communication terminal device ( 10 ) includes a first communication unit ( 131 ) that communicates with the first communication terminal device ( 20 ) by using the first communication scheme; a second communication unit ( 132 ) that communicates with the management device ( 30 ) by using a second communication scheme capable of communication over a longer distance than the first communication scheme; a searching unit ( 114 ) that searches for the first communication terminal device ( 20 ) via the first communication unit ( 131 ) and acquires the first identifier of the first communication terminal device ( 20 ) detected by the search; and a communicating unit ( 118 ) that communicates information including the first identifier acquired by the searching unit ( 114 ) to the management device ( 30 ) via the second communication unit ( 132 ). The management device ( 30 ) includes: a communication unit ( 331 ) that communicates by using the second communication scheme; a storage unit ( 32 ) that stores identifier mapping information that maps the first identifier to the second identifier; a communication acquisition unit ( 313 ) that receives communication of information including the first identifier from the second communication terminal ( 10 ) via the communication unit ( 331 ); and a communication destination determination unit ( 317 ) that acquires the second identifier mapped to the first identifier acquired by the communication acquisition unit ( 313 ) by referring to the identifier mapping information stored in the storage unit ( 32 ). 
     Still another embodiment of the present invention relates to a communication method. The method comprises: searching for a first communication terminal device ( 20 ) by using a first communication scheme for communication with the first communication terminal device ( 20 ) and acquiring a first identifier of the first communication terminal device ( 20 ) detected by the search; and acquiring a second identifier mapped to the first identifier acquired by the search, by referring to identifier mapping information that maps the first identifier for identifying the first communication terminal device ( 20 ) to the second identifier for identifying a second communication terminal device ( 10 ) that communicates by using a second communication scheme capable of communication over a longer distance than the first communication scheme. 
     Still another embodiment of the present invention also relates to a communication method. The method is adapted to a communication system ( 1 ) including a first communication terminal device ( 20 ) identified by a first identifier, a second communication terminal device ( 10 ) identified by a second identifier, and a management device ( 30 ), the method comprising using the first communication terminal device ( 20 ) to communicate with the second communication terminal device ( 10 ) by using a first communication scheme. The method further comprises: using the second communication terminal device ( 10 ) to communicate with the first communication terminal device ( 20 ) by using the first communication scheme; using the second communication terminal device ( 10 ) to communicate with the management device ( 30 ) by using a second communication scheme capable of communication over a longer distance than the first communication scheme; using the second communication terminal device ( 10 ) to search for the first communication terminal device ( 20 ) by using the first communication scheme and acquiring the first identifier of the first communication terminal device ( 20 ) detected by the search; and using the second communication terminal device ( 10 ) to communicate information including the first identifier acquired by the search to the management device ( 30 ) by using the second communication scheme. The method further comprises: using the management device ( 30 ) to communicate by using the second communication scheme; using the management device ( 30 ) to receive the information including the first identifier from the second communication terminal device ( 10 ) by using the second communication scheme; and using the management device ( 30 ) to acquire the second identifier mapped to the acquired first identifier by referring to mapping information that maps the first identifier to the second identifier. 
     Optional combinations of the aforementioned constituting elements, and implementations of the invention in the form of methods, apparatuses, systems, recording mediums, and computer programs may also be practiced as additional modes of the present invention. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Embodiments will now be described by way of examples only, with reference to the accompanying drawings which are meant to be exemplary, not limiting and wherein like elements are numbered alike in several Figures in which: 
         FIG. 1  shows the configuration of the dangerous operation support system according to the embodiments of the present invention; 
         FIG. 2  shows the configuration of the biosensor device according to the embodiments; 
         FIG. 3  shows the configuration of the terminal device according to Embodiment 1; 
         FIG. 4  shows the configuration of the management device according to Embodiment 1; 
         FIG. 5  is a flowchart illustrating the pairing process performed in a preparatory stage; 
         FIG. 6  is a flowchart showing the flow of the basic process in the dangerous operation support system; 
         FIG. 7  is a flowchart illustrating a method of requesting a rescue by using the dangerous operation support system according to Embodiment 1; 
         FIG. 8  is a flowchart illustrating a method of requesting a rescue by using the dangerous operation support system according to a variation to Embodiment 1; 
         FIG. 9  shows the configuration of the terminal device according to Embodiment 2; 
         FIG. 10  shows the configuration of the management device according to Embodiment 2; 
         FIG. 11  is a flowchart illustrating a method of requesting a rescue by using the dangerous operation support system according to Embodiment 2; and 
         FIG. 12  is a flowchart illustrating a method of requesting a rescue by using the dangerous operation support system according to a variation to Embodiment 2. 
     
    
    
     DETAILED DESCRIPTION 
     The invention will now be described by reference to the preferred embodiments. This does not intend to limit the scope of the present invention, but to exemplify the invention. 
     Embodiments of the present invention relate to a dangerous operation support system for supporting firefighting operations of a firefighting team formed by multiple firefighters. In the following description, a firefighting operation is taken by as an example. A firefighting operation is given as an example of dangerous operations and the system is applicable to dangerous operations in general in which multiple workers cooperate. For example, the system is applicable to rescue operations or recovery operations undertaken in the event of a natural disaster such as an earthquake or landslide. The system is also applicable to operations in dangerous places such as sites of mine development. 
       FIG. 1  shows the configuration of a dangerous operation support system  1  according to the embodiments of the present invention. The dangerous operation support system  1  includes a management device  30  installed at a command center  3 , a biosensor device  20  worn by each worker, and a terminal device  10  held or carried by each worker. In this specification, a case of three workers is taken as an example. 
     The biosensor device  20  is worn by the body of the worker and detects biological information such as heart rate, body temperature, and posture. The biosensor device  20  is available in various types including a type glued to the body by a gel pad, a type wound around the arm or leg by a band, a type attached inside a clothing. Near field communication is established between the biosensor device  20  and the terminal device  10 . In this specification, an example in which Bluetooth (registered trademark) is used as near field communication is described. Near field communication other than Bluetooth (registered trademark), such as wireless LAN, infrared communication, may be used for near field communication. 
     A simplified mobile wireless device for business wireless communication is used as the terminal device  10 . The management device  30  is installed at a place such as a fire station or command van that serves as the command center  3 . The management device  30  may be implemented by a PC connected to the base station radio device for business wireless communication. Instead of using business wireless communication, an ordinary cell phone network may be used. In this case, the terminal device  10  may be implemented by an ordinary mobile terminal device such as a smartphone, feature phone, etc. The management device  30  may be implemented by a PC connected to the IP network. In the description below, business wireless communication is assumed to be used. 
       FIG. 2  shows the configuration of the biosensor device  20  according to the embodiments. The biosensor device  20  includes a control unit  21 , a storage unit  22 , a communication unit  23 , a sensor unit  24 , and a controller  25 . The control unit  21  includes a biological information acquisition unit  211 , a biological information communicating unit  212 , a mode control unit  213 , and a pairing management unit  214 . The functions of the control unit  21  are implemented by the coordination of hardware resources and software resources, or hardware resources alone. A processor, ROM, RAM, and other LSIs can be used as hardware resources. Programs such as firmware can be used as software resources.  FIG. 2  depicts only those function blocks of the control unit  21  related to the process of interest in the embodiments. 
     The storage unit  22  includes a storage medium such as a nonvolatile semiconductor memory. The communication unit  23  includes a near field communication unit  231 . Medium or long distance wireless communication capabilities of a business wireless communication system, a cell phone network, etc. are not provided. The sensor unit  24  includes a heart rate sensor, a body temperature sensor, a three-axis acceleration sensor or the like to detect the heat rate, body temperature, posture or the like of the worker wearing the device. The sensor unit  24  outputs the detected biological information to the control unit  21 . 
     The biological information acquisition unit  211  acquires the detected biological information from the sensor unit  24 . The biological information communicating unit  212  periodically (e.g., at the intervals of several seconds) communicates the acquired biological information to the terminal device  10  paired with the biosensor device  20  via the near field communication unit  231 . A description of the mode control unit  213  and the pairing management unit  214  will be given later. The configuration of the biosensor device  20  shown in  FIG. 2  is common to Embodiments 1 and 2 described below. 
     (Embodiment 1) 
       FIG. 3  shows the configuration of the terminal device  10  according to Embodiment 1. The terminal device  10  includes a control unit  11 , a storage unit  12 , a communication unit  13 , a display unit  14 , a controller  15 , and a sound input and output unit  16 . The control unit  11  includes a biological information acquisition unit  111 , a biological information communicating unit  112 , a biological information evaluation unit  113 , a searching unit  114 , a pairing management unit  115 , a communication destination determination unit  116 , an electric field detection unit  117 , a rescue request communicating unit  118 , and a mode switching instruction communicating unit  119 . The functions of the control unit  21  are also implemented by the coordination of hardware resources and software resources, or hardware resources alone.  FIG. 3  depicts only those function blocks of the control unit  11  related to the process of interest in Embodiment 1. 
     The storage unit  12  includes a storage medium such as a nonvolatile semiconductor memory. The storage unit  12  includes a biosensor ID storage unit  121 .  FIG. 3  also depicts only those function blocks of the storage unit  12  related to the process of interest in Embodiment 1. The biosensor ID storage unit  121  stores identification information on multiple biosensor devices  20  respectively worn by multiple workers belonging to a team undertaking a disaster-relief operation in cooperation with each other. The sound input and output unit  16  includes a microphone and a speaker. 
     The communication unit  13  includes a near field communication unit  131  and a business wireless communication unit  132 . The near field communication unit  131  is used for communication with the biosensor device  20  and the business wireless communication unit  132  is used for communication with the management device  30  or another terminal device  10 . 
       FIG. 4  shows the configuration of the management device  30  according to Embodiment 1. The management device  30  includes a control unit  31 , a storage unit  32 , a communication unit  33 , a display unit  34 , a controller  35 , and a sound input and output unit  36 . The control unit  31  includes a biological information acquisition unit  311 , a display control unit  312 , a rescue request acquisition unit  313 , and a communication destination determination unit  317 . The functions of the control unit  31  are also implemented by the coordination of hardware resources and software resources, or hardware resources alone.  FIG. 4  also depicts only those function blocks of the control unit  31  related to the process of interest in Embodiment 1. 
     The storage unit  32  includes a storage medium such as a nonvolatile semiconductor memory. The storage unit  32  includes a device information storage unit  321 .  FIG. 4  also depicts only those function blocks of the storage unit  32  related to the process of interest in Embodiment 1. The device information storage unit  321  stores the name of a worker, identification information on the terminal device  10  carried by the worker, and identification information on the biosensor device  20  worn by the worker, mapping the information to each other. The terminal device  10  and the biosensor device  20  may be permanently assigned to each worker for use. Alternatively, the terminal device  10  and the biosensor device  20  used may be dynamically changed. The sound input and output unit  36  includes a microphone and a speaker. 
     The operation of the terminal device  10 , the biosensor device  20 , and the management device  30  will be described below in specific details with reference to  FIGS. 5-8 . First, a description will be given of the process performed before a worker arrives at a scene of a disaster. Each worker should pair the biosensor device  20  worn by the worker, a slave module of Bluetooth (registered trademark) (hereinafter, simply referred to as a slave module), and the terminal device  10  that the worker carries with him or her, a master module of Bluetooth (registered trademark) (hereinafter, simply referred to as a master module). The biosensor device  20  is in either of two modes including the normal mode in which the device does not respond to a pairing search from the master and the pairing mode in which the device responds to a pairing search from the master. In the normal mode, the existence of the device is not disclosed to a search from the master module to protect privacy and prevent unauthorized access. 
       FIG. 5  is a flowchart illustrating the pairing process in the preparatory stage. When worker A uses the controller  25  of the biosensor device  20   a  to designate a transition to the pairing mode, the mode control unit  213  of the biosensor device  20  causes the host device to make a transition from the normal mode to the pairing mode (S 01 A). When worker A uses the controller  15  of the terminal device  10   a  to request a pairing search, the searching unit  114  starts searching for a device capable of pairing connection (S 02 A). The pairing search detects a device capable of pairing connection and located within the range of near field communication. Only those devices that are in the pairing mode are detected, and devices in the normal mode are not detected. 
     When worker A uses the controller  15  of the terminal device  10   a  to select the biosensor device  20   a,  the pairing management unit  115  determines the selected biosensor device  20   a  as the pairing device (S 03 A) and establishes pairing with the biosensor device  20   a  (S 04 A). Similarly, the pairing management unit  214  of the biosensor device  20   a  establishes pairing with the terminal device  10   a  (S 04 A). When pairing is established, the mode control unit  213  of the biosensor device  20   a  causes the host device to make a transition from the pairing mode to the normal mode (S 05 A). When pairing is established, the pairing management unit  115  of the terminal device  10   a  communicates, to the management device  30 , pairing information including the identification information on the terminal device  10   a,  the identification information on the biosensor device  20   a,  and the name of the worker (S 06 A). 
     The identification information on the pairing device is stored in the storage unit  12  of the terminal device  10   a  and the storage unit  22  of the biosensor device  20   a.  This allows the terminal device  10   a  and the biosensor device  20   a  to establish pairing automatically when they are turned on subsequently. Like worker A, worker B and worker C also pair the terminal devices  10   b  and  10   c  with the biosensor devices  20   b  and  20   c,  respectively. The control unit  31  of the management device  30  acquires pairing information from the terminal devices  10   a,    10   b,  and  10   c  and stores the acquired information in the device information storage unit  321  (S 07 ). If the terminal device  10  and the biosensor device  20  are permanently assigned to each worker for use, the processes in step S 06  and S 07  are omitted. 
     A description will now be given of the process performed during a firefighting operation at a scene of a disaster. The biosensor devices  20   a - 20   c  are worn by the bodies of workers A-C. The workers A-C hold the terminal devices  10   a - 10   c,  respectively. The biosensor devices  20   a - 20   c  and the terminal devices  10   a - 10   c  are respectively paired by near field communication. The terminal devices  10   a - 10   c  are master modules and the biosensor devices  20   a - 20   c  are slave modules. 
       FIG. 6  is a flowchart showing the flow of the basic process in the dangerous operation support system  1 . The biological information acquisition unit  211  of the biosensor device  20   a  acquires biological information on worker A from the sensor unit  24 . The biological information communicating unit  212  communicates the acquired biological information to the terminal device  10   a  by near field communication (S 11 A). 
     The biological information acquisition unit  111  of the terminal device  10   a  paired with the biosensor device  20   a  acquires the biological information from the biosensor device  20   a  by near field communication. The biological information communicating unit  112  communicates the biological information to the management device  30  of the command center  3  by business wireless communication (S 12 A). The biological information on workers B and C are similarly communicated to the management device  30  of the command center  3 . 
     The biological information acquisition unit  311  of the management device  30  acquires the biological information on workers A-C by business wireless communication. The display control unit  312  causes the display unit  34  to display the acquired biological information on workers A-C (S 13 ). The commander at the command center  3  monitors the biological information on workers A-C displayed on the display unit  34  and know the states of workers A-C. The commander sends commands based on the states of workers A-C thus known. For example, if the heart rate of worker A shows an abnormal increase, the commander directs worker A to stop the firefighting operation and pull out. For example, the direction is given by outputting sound from the sound input and output unit  36  to the terminal device  10   a  carried by firefighter A by business wireless communication. 
       FIG. 7  is a flowchart illustrating a method of requesting a rescue by using the dangerous operation support system  1  according to Embodiment 1. The biological information acquisition unit  211  of the biosensor device  20   a  acquires biological information on worker A from the sensor unit  24 . The biological information communicating unit  212  communicates the acquired biological information to the terminal device  10   a  by near field communication (S 21 A). 
     The biological information acquisition unit  111  of the terminal device  10   a  paired with the biosensor device  20   a  acquires the biological information on worker A from the biosensor device  20   a  by near field communication. The biological information evaluation unit  113  determines whether the acquired biological information on worker A is normal. For example, the biological information evaluation unit  113  determines whether the heart rate is accommodated within the normal range. If it is not accommodated in the normal range, a determination of abnormality is yielded. If the biological information is abnormal, it is estimated that worker A is in a dangerous state. 
     The biological information may be evaluated in the biosensor device  20   a.  In this case, flag information indicating normality/abnormality is appended to the biological information transmitted from the biosensor device  20   a.  If biological information is evaluated in the biosensor device  20   a,  the biological information evaluation unit  113  of the terminal device  10   a  can be omitted. 
     If the biological information on worker A is determined to be abnormal, the mode switching instruction communicating unit  119  of the terminal device  10   a  communicates a mode switching instruction to the other terminal devices  10   b  and  10   c  by business wireless communication to direct the other terminal devices  10   b  and  10   c  to switch the mode of the biosensor devices  20   b  and  20   c  to the pairing mode (S 22 A). When the mode switching instruction communicating unit  119  of the terminal device  10   b  acquires the mode switching instruction from the terminal device  10   a  by business wireless communication, the mode switching instruction communicating unit  119  communicates the mode switching instruction to the biosensor device  20   b  by near field communication (S 23 B). When the mode control unit  213  of the biosensor device  20   b  acquires the mode switching instruction from the terminal device  10   b  by near field communication, the mode control unit  213  causes the biosensor device  20   b  to make a transition from the normal mode to the pairing mode (S 24 B). 
     The terminal device  10   c  and the biosensor device  20   c  operate similarly. This allows the biosensor devices  20   b  and  20   c  to be detected by the terminal device  10   a.  If the devices are configured to return a response to a pairing search from other devices in the normal mode as well, the processes in steps S 22 A, S 23 B, S 23 C, S 24 B, and S 24 C are omitted. 
     The searching unit  114  of the terminal device  10   a  starts a pairing search to search for a device connectable by near field communication (S 25 A). As a result of the search, the biosensor device  20   b  worn by worker B at a location capable of near field communication with the terminal device  10   a  held by worker A, i.e., near the terminal device  10   a,  is detected as a pairing candidate. Meanwhile, the biosensor device  20   c  worn by worker C at a location incapable of near field communication with the terminal device  10   a  held by worker A, i.e., not near the terminal device  10   a,  is not detected as a pairing candidate (S 26 A). For example, given that Class 2 Bluetooth (registered trademark) is used, communication is disabled at a distance of about 10 m or more. The searching unit  114  acquires the identification information on the biosensor device  20   b  identified by the search from the biosensor device  20   b  via the near field communication unit  131  (S 26 A). 
     The rescue request communicating unit  118  communicates, to the management device  30 , a rescue request including information indicating that worker A is in a dangerous state and the information acquired by the searching unit  114  (the identification information (ID=B) of the biosensor device  20   b,  in the case of  FIG. 3 ) by business wireless communication. 
     The rescue request acquisition unit  313  of the management device  30  acquires the rescue request from the terminal device  10   a  by business wireless communication. The communication destination determination unit  317  acquires the identification information on the terminal device  10  mapped to the identification information on the biosensor device  20  acquired by the rescue request acquisition unit  313 , based on the device information stored in the device information storage unit  321 . The display control unit  312  causes the display unit  34  to display that worker A is in a dangerous state and that worker B is nearby. The display control unit  312  also causes the display unit  34  to display the device information on worker B acquired from the device information storage unit  321 . The commander viewing the screen on which these items of information are shown tells worker B that worker A in a dangerous state is nearby and directs worker B to rescue worker A. For example, the commander sends sound to the terminal device  10   b  by business wireless communication (S 28 ). 
     If multiple biosensor devices  20  connectable to the terminal device  10   a  by near field communication are detected as a result of the pairing search in step S 26 A above, the electric field detection unit  117  detects the radio field intensity of response signals transmitted from the connectable biosensor devices  20 . It is estimated that the higher the radio field intensity, the closer to the terminal device  10   a.  If the devices are configured to return a response to a pairing search from other devices in the normal mode as well, the processes in steps S 22 A, S 23 B, S 23 C, S 24 B, and S 24 C are omitted. In this case, the biosensor device  20   a  worn by the worker himself is excluded from the candidates of destination of communication. 
     Alternatively, the rescue request communicating unit  118  may communicate information on destinations of sending a rescue request by communicating the identification information on all the biosensor devices  20  detected as a result of the pairing search and the radio field intensity of the respective biosensor devices  20 . The commander at the command center  3  can determine the destination to send a rescue request based on the information on radio field intensity. 
     As described above, the terminal device  10   a  according to this embodiment performs the processes based on the radio field intensity in near field communication from the respective biosensor devices  20  instead of the radio field intensity in business wireless communication from the respective terminal devices  10 . This is because the output voltage in business wireless communication or cell phone communication is higher than that of near field communication so that it is difficult to estimate the distance from other workers located at the same scene based on the radio field intensity. If a scheme of communication routed by a base station or a relay station is employed for business wireless communication or cell phone communication, the radio field intensity detected will represent the intensity of radio field from the base station or the relay station, which is another reason why it is impossible to estimate the distance from the respective terminal devices  10  in communication. 
     If multiple biosensor devices  20  connectable to the terminal device  10   a  by near field communication are detected as a result of the pairing search in step S 26 A above, the pairing management unit  115  of the terminal device  10   a  may establish pairing with all the biosensor devices  20  detected. If the system is designed to enable only one-to-one pairing, the terminal device  10   a  and the detected biosensor devices  20  cancel the pairing established previously and establish pairing between the terminal device  10   a  and the detected biosensor device  20 . 
     The biological information acquisition unit  111  of the terminal device  10   a  acquires biological information from the biosensor device  20  newly paired with the terminal device  10   a.  The biological information evaluation unit  113  determines whether the value indicated by the biological information is in a dangerous range. If the value indicated by the biological information is in a dangerous range, the terminal device  10  held by the worker wearing the biosensor device  20  is excluded from the destinations of sending a rescue request. In other words, the rescue request communicating unit  118  excludes the terminal device  10  held by the worker for which the value indicated by the biological information is in a dangerous range from the destinations of sending a rescue request. 
     The pairing management unit  115  of the terminal device  10   a  cancels pairing with the associated biosensor device  20  and establishes pairing with another biosensor device  20  connectable with the terminal device  10   a  by near field communication. The process is performed for all the biosensor devices  20  detected. When the biological information acquired from all the biosensor devices  20  detected has been evaluated, the terminal device  10   a  and the detected biosensor devices  20  return the pairing devices to the original state. 
       FIG. 8  is a flowchart illustrating a method of requesting a rescue by using the dangerous operation support system  1  according to a variation to Embodiment 1. The processes through step S 26 A of the flowchart of  FIG. 8  are the same as those of the flowchart of  FIG. 7 . In the variation, the storage unit  12  of the terminal device  10  is also provided with a device information storage unit, like the storage unit  32  of the management device  30 . 
     In the variation, the terminal device  10   a  directly sends a rescue request to worker B without being mediated by the command center  3 . In other words, the rescue request communicating unit  118  of the terminal device  10   a  communicates a rescue request to the terminal device  10   b  held by worker B by business wireless communication, based on the result of pairing search (S 29 A). Since the terminal device  10   b  is within the range covered by radio waves for near field communication, the terminal device  10   b  may communicate a rescue request by near field communication instead of business wireless communication. If a display unit is provided in the biosensor device  20 , the rescue request communicating unit  118  may communicate a rescue request to the biosensor device  20   b  by near field communication. 
     If multiple biosensor devices  20  connectable to the terminal device  10   a  by near field communication are detected as a result of the pairing search in step S 26 A above, the communication destination determination unit  116  determines the terminal device  10  held by the worker wearing the biosensor device  20  (one of the multiple biosensor devices  20  that are connectable) with the highest radio field intensity as the destination of sending a rescue request. A rescue request may be sent to multiple destinations. In this case, the communication destination determination unit  116  identifies a preset number of biosensor devices in the descending order of radio field intensity, from the multiple connectable biosensor devices  20 . The communication destination determination unit  116  determines multiple terminal devices  10  held by multiple workers wearing the identified biosensor devices  20  as the destination of sending a rescue request. 
     Of the pairing candidates detected in step S 26 A above, the communication destination determination unit  116  only defines the terminal device  10  held by the worker wearing the biosensor device  20  having its identification information stored in the device information storage unit as the candidate of sending a rescue request. In other words, the rescue request communicating unit  118  excludes the terminal device  10   a  held by a worker other the workers belonging to the same team from the targets of communicating a rescue request. If the biosensor device  20  as detected is of the same type as the biosensor device  20  of the requesting worker but is worn by a worker of another team, the terminal device  10  held by the worker wearing the detected biosensor device  20  is excluded from the destinations of sending a rescue request. 
     As described above, according to Embodiment 1, a dangerous state of a worker can be made known to nearby workers smoothly by identifying the nearby worker using a pairing search in near field communication. By detecting the radio field intensity in near field communication, a worker estimated to be closest to the worker in the dangerous state can be identified. A worker estimated to be closest can be identified even if the worker is operating in a scene not covered by GPS waves. 
     (Embodiment 2) 
       FIG. 9  shows the configuration of the terminal device  10  according to Embodiment 2. The control unit  11  of the terminal device  10  according to Embodiment 2 includes a biological information acquisition unit  111 , a biological information communicating unit  112 , a biological information evaluation unit  113 , a searching unit  114 , a pairing management unit  115 , an electric field detection unit  117 , a search instruction communicating unit  118   a,  a mode switching instruction communicating unit  119 , a search result communicating unit  1110 , and a presentation control unit  1111 . The features other than the control unit  11  are identical to the features of the management device  30  according to Embodiment 1 shown in  FIG. 3 . 
       FIG. 10  shows the configuration of the management device  30  according to Embodiment 2. The control unit  31  of the management device  30  according to Embodiment 2 includes a biological information acquisition unit  311 , a display control unit  312 , a search result acquisition unit  313   a,  a biological information evaluation unit  314 , a mode switching instruction communicating unit  315 , and a search instruction communicating unit  316 . The features other than the control unit  31  are identical to the features of the management device  30  according to Embodiment 1 shown in  FIG. 4 . 
       FIG. 11  is a flowchart illustrating a method of requesting a rescue by using the dangerous operation support system  1  according to Embodiment 2. The biological information acquisition unit  211  of the biosensor device  20   a  acquires biological information on worker A from the sensor unit  24 . The biological information communicating unit  212  communicates the acquired biological information to the terminal device  10   a  by near field communication (S 31 A). 
     The biological information acquisition unit  111  of the terminal device  10   a  paired with the biosensor device  20   a  acquires the biological information on worker A from the biosensor device  20   a  by near field communication. The biological information communicating unit  112  communicates the biological information on worker A to the management device  30  of the command center  3  by business wireless communication (S 32 A). The biological information acquisition unit  311  of the management device  30  acquires the biological information on worker A from the terminal device  10   a  by business wireless communication. The biological information evaluation unit  314  determines whether the acquired biological information on worker A is normal. 
     If the biological information on worker A is determined to be abnormal, the mode switching instruction communicating unit  315  of the management device  30  communicates a mode switching instruction to the terminal device  10   a  by business wireless communication to direct the terminal device  10   a  to switch the biosensor device  20   a  from the normal mode to the pairing mode (S 33 ). When the mode switching instruction communicating unit  119  of the terminal device  10   a  acquires the mode switching instruction from the management device  30  by business wireless communication, the mode switching instruction communicating unit  119  communicates the mode switching instruction to the biosensor device  20   a  by near field communication (S 34 A). When the mode control unit  213  of the biosensor device  20   a  acquires the mode switching instruction from the terminal device  10   a  by near field communication, the mode control unit  213  causes the biosensor device  20   a  to make a transition from the normal mode to the pairing mode (S 35 A). If the devices are configured to return a response to a pairing search from other devices in the normal mode as well, the processes in steps S 33 , S 34 A, and S 35 A are omitted. 
     After the biosensor device  20   a  has made a transition to the pairing mode, the search instruction communicating unit  316  of the management device  30  communicates a search instruction to the terminal devices  10   b  and  10   c  worn by workers B and C, respectively, by business wireless communication, to direct the terminal devices  10   b  and  10   c  to initiate a pairing search for the biosensor device  10   a  worn by worker A by near field communication (S 36 ). The identification information (ID=A) of the biosensor device  20   a  searched for is appended to the search instruction. 
     Upon acquiring the search instruction from the management device  30 , the searching unit  114  of the terminal device  10   b  starts a pairing search to search for a device connectable by near field communication (S 37 B). The terminal device  10   b  held by worker B is at a distance capable of near field communication with the biosensor device  20   a,  the biosensor device  20   a  searched for is detected as a pairing candidate (S 38 B). 
     The presentation control unit  1111  causes the display unit  14  to display that worker A in a dangerous state is nearby. This allows worker B to recognize that worker A in need of a rescue is within the range covered by radio waves for near field communication. The presentation control unit  1111  may cause the sound input and output unit  16  to output a sound to alarm that worker A in a dangerous state is nearby. The search result communicating unit  1110  communicates a search result including a message indicating that the biosensor device  20   a  searched for is successfully detected to the management device  30  by business wireless communication (S 39 B). 
     As in the terminal device  10   a,  the searching unit  114  of the terminal device  10   c  also starts a pairing search for a device connectable by near field communication, upon acquiring a search instruction from the management device  30  (S 37 C). Since the terminal device  10   c  held by worker C is not within the range covered by radio waves for near field communication with the biosensor device  20   a,  the biosensor device  20   a  searched for is not detected as a pairing candidate (S 38 C). The search result communicating unit  1110  communicates a search result, including a message indicating the failure to detect the biosensor device  20   a  searched for, to the management device  30  by business wireless communication (S 39 C). 
     The search result acquisition unit  313   a  of the management device  30  acquires the search result from the terminal devices  10   b  and  10   c  by business wireless communication. The display control unit  312  causes the display unit  34  to display that worker B is near worker A in a dangerous state. The display control unit  312  also acquires the device information on worker B from the device information storage unit  321  and causes the display unit  34  to display the acquired information. The commander viewing the screen on which these items of information are shown tells worker B that worker A in a dangerous state is nearby and to rescue worker A. For example, the commander sends sound from the sound input and output unit  16  to the terminal device  10   b  by business wireless communication (S 399 ) to give the instruction. 
     In step S 38 B above, the electric field detection unit  117  of the terminal device  10   b  may detect the radio field intensity of a response signal transmitted from the biosensor device  20   a  detected by the pairing search. The search result communicating unit  1110  communicates a search result including a message indicating that the biosensor device  20   a  worn by worker A is successfully detected and the detected radio field intensity to the management device  30  by business wireless communication. By reporting a search result including the radio field intensity to the command center  3  in a case the biosensor device  20   a  worn by worker A is detected by multiple terminal devices  10 , the commander can know which worker is closest to worker A by referring to the radio field intensity. 
     After step S 38 B above, the pairing management unit  115  of the terminal device  10   b  may establish pairing with the biosensor device  20   a  worn by worker A detected. If the system is designed to enable only one-to-one pairing, the terminal device  10   b  and the biosensor devices  20   a  detected by the pairing search temporarily cancel the pairing established previously and establish pairing between the terminal device  10   b  and the biosensor device  20   a.    
     The biological information acquisition unit  111  of the terminal device  10   b  acquires biological information from the biosensor device  20   a  newly paired with the terminal device  10   b.  The presentation control unit  1111  causes the display unit  14  to display the acquired biological information and/or causes the sound input and output unit  16  to output sound. For example, the numerical value of the acquired biological information may be read out by speech synthesis. Worker B can know how dangerous worker A is by referring to the presented biological information and use it to build a rescue plan. 
       FIG. 12  is a flowchart illustrating a method of requesting a rescue by using the dangerous operation support system  1  according to a variation to Embodiment 1. The biological information acquisition unit  211  of the biosensor device  20   a  acquires biological information on worker A from the sensor unit  24 . The biological information communicating unit  212  communicates the acquired biological information to the terminal device  10   a  by near field communication (S 31 A). 
     The biological information acquisition unit  111  of the terminal device  10   a  paired with the biosensor device  20   a  acquires the biological information on worker A from the biosensor device  20   a  by near field communication. The biological information evaluation unit  113  determines whether the acquired biological information on worker A is normal. If the biological information on worker A is determined to be abnormal, the mode switching instruction communicating unit  119  communicates a mode switching instruction to the biosensor device  20   a  by business wireless communication to direct the biosensor device  20   a  to switch from the normal mode to the pairing mode (S 34 A). When the mode control unit  213  of the biosensor device  20   a  acquires the mode switching instruction from the terminal device  10   a  by near field communication, the mode control unit  213  causes the biosensor device  20   a  to make a transition from the normal mode to the pairing mode (S 35 A). If the devices are configured to return a response to a pairing search from other devices in the normal mode as well, the processes in steps S 34 A and S 35 A are omitted. 
     The subsequent processes are identical the processes following steps S 35 B and S 35 C in the flowchart of  FIG. 11 . In the variation, the search result communicating unit  1110  of the terminal devices  10   b  and  10   c  may communicate the search result to both of the requesting terminal device  10   a  and the management device  30  by business wireless communication (S 39 B, S 39 C). 
     As described above, according to Embodiment 2, a dangerous state of a worker can be made known to a nearby worker smoothly by identifying the nearby worker using a pairing search in near field communication. Since multiple terminal devices  10  conduct a pairing search for the biosensor device  20  worn by the worker in a dangerous state, the redundancy is high. Even if a trouble occurs in the near field communication unit  131  of one of the terminal devices  10 , the worker holding another terminal device  10  detecting the biosensor device  20  can come to a rescue. 
     Described above is an explanation based on an exemplary embodiment. The embodiment is intended to be illustrative only and it will be obvious to those skilled in the art that various modifications to constituting elements and processes could be developed and that such modifications are also within the scope of the present invention. 
     In Embodiment 1, the searching unit  114  of the terminal device  10   a  searches for a device connectable in near field communication when the biological information on worker A detected by the biosensor device  20   a  is abnormal. A trigger other than abnormality in biological information can start a search so long as the trigger indicates abnormality in worker A undertaking a dangerous operation. For example, a heat sensor or a smoke sensor may be provided in the terminal device  10  held by worker A and, if it is estimated that worker A falls to the floor by referring to the output values from the sensor, a search may be started. A search may be alternatively started when worker A presses down a rescue request button of the controller  15  of the terminal device  10   a.    
     In Embodiments 1 and 2, the biosensor device  20  is searched for in a pairing search as a slave module in near field communication. The terminal devices  10  held by other workers may also be searched for in the pairing search. Since the biosensor device  20  is less likely to be removed from the body of a worker than the terminal device  10 , it would be appropriate to use the result of search for the biosensor device  20  in preference to the result of search for the terminal device  10 , if the results differ. 
     The biosensor device  20  according to Embodiments 1 and 2 is an example of communication terminal device on which the near field communication unit  131  is mounted and on which the business wireless communication unit  132  or a cell phone communication unit is not mounted. Therefore, an accessory device such as a headset that supports Bluetooth (registered trademark) may be used in place of the biosensor device  20 .