Device, method and system for selecting emergency vehicles

A device for selecting vehicles to be sent to a site of a fire is provided. The device includes a storage unit provided with a vehicle table and a fire-spreading condition table. Fire-extinguishing ability data and arrival time data for each vehicle are stored in the vehicle table as numerical data. Initial fire power data and fire-spreading rate data are stored in the fire-spreading condition table as numerical data. The device also includes a vehicle organizing part deriving a relationship between total fire-extinguishing ability of vehicles and total fire-spreading power of the fire with respect to time, and selecting vehicles to be sent to the fire site based on the relationship.

BACKGROUND OF THE INVENTION
 1. Field of the Invention
 The present invention generally relates to a method of selecting vehicles
 and a device and system for implementing such a method, and particularly
 relates to a method of appropriately selecting vehicles to be sent upon
 occurrence of a disaster or a fire and a device and system for
 implementing such a method.
 2. Description of the Related Art
 In the conventional emergency command system, emergency vehicles to be sent
 to a disaster are fixedly predetermined based on types and locations of
 the disaster. Thus, when a disaster is reported through an emergency call,
 emergency vehicles are selected in accordance with the type and location
 of the reported disaster. An emergency command including thus-selected
 emergency vehicles is issued.
 FIG. 1 is a diagram showing an example of a device for selecting emergency
 vehicles, which device may be a command controller 20.
 The command controller 20 includes a man-machine interface 22, a vehicle
 organizing part 24, a command producing part 26, an affected object file
 28, and a vehicle team table 30. When a disaster is reported through an
 emergency call, an operator questions the reporter to obtain information
 about the condition, the location and the affected object (e.g., the name
 of an affected building, the name of an affected forest, etc.,) of the
 disaster. In the present example, the disaster may be a fire. Then, the
 operator inputs data of thus-obtained information of the disaster to the
 command controller 20 via the man-machine interface 22.
 The data input via the man-machine interface 22 is supplied to the vehicle
 organizing part 24. Then, the vehicle organizing part 24 searches for a
 vehicle team key from the affected object file 28, which key is
 predetermined for the location and affected object of the disaster. The
 term "vehicle team" is understood as a team including a plurality of
 vehicles assigned based on the affected object of the disaster, such that
 the number of vehicles exceeds a minimum number required to deal with the
 affected object. The vehicle organizing part 24 then retrieves vehicle
 data from the vehicle team table 30 using the vehicle team key.
 Then, the vehicle organizing part 24 sends the vehicle data to a vehicle
 management device 10. The vehicle management device 10 includes a vehicle
 management part 12 having a vehicle management table with which all the
 vehicles can be managed such that the same vehicle will not be assigned to
 different disasters. In detail, the vehicle management part 12 checks
 whether the vehicle corresponding to the vehicle data supplied from the
 vehicle organizing part 24 has already been assigned to another disaster.
 If not, the relevant vehicle is reserved as an operational vehicle for the
 reported disaster.
 Upon receiving a message from the vehicle management part 12 announcing
 that the operational vehicle has been reserved, the vehicle organizing
 part 24 instructs the command producing part 26 to produce a command for
 the operational vehicle. The command producing part 26 produces the
 command for the operational vehicle and sends the command in the form of
 electronic data to an emergency station to which the operational vehicle
 belongs and to the operational vehicle itself. The emergency station is a
 facility such as a main station or a branch station to which emergency
 vehicles belong. In the following description, the emergency station is
 also referred to as a "station". The command includes data such as a type
 of the disaster, an address, affected objects, operational vehicles, and a
 map.
 At the station where the operational vehicle belong, a command tone, a
 voice signal and the command are output from output means such as a
 terminal display and a printer. Also, a command tone and a voice signal
 are sent to the relevant operational vehicle.
 In the case of a disaster, the operational vehicles are sent to the
 location of the disaster. This results in a reduced disaster-handling
 ability of the station to which the operational vehicles belong and the
 nearby stations. This may cause a problem if another (or a second)
 disaster occurs while the operational vehicles are sent to the location of
 the first disaster. As a result, if the first disaster is severe, since
 the disaster-handling ability of the area covered by the relevant station
 will become too small, the operator demands assistance from other stations
 based on his/her experience. The demand for assistance is submitted by
 means of a voice message or by an electronic message.
 Further, in the case of a more severe disaster, such as an earthquake, the
 head or the leading member of the station submits the demand for
 assistance to other geographically remote fire defense organizations by
 making a telephone call or by other communication means.
 Conventionally, since the operational vehicles to be assigned to a disaster
 are predetermined according to the location and the affected object of the
 disaster, initially, the number of vehicles reserved as operational
 vehicles may not be sufficient for the relevant disaster. Therefore, there
 may be a case where the number of operational vehicles is excessive or
 insufficient. Particularly, when there is a shortage of operational
 vehicles, it is necessary to demand assistance vehicles based on the
 report about the recent state of the disaster. In the case of a fire, the
 recent state may be a state of spread of the fire. Accordingly, the
 conventional system has a drawback that an optimal number of operational
 vehicle cannot be selected in a quick and efficient manner.
 Another drawback of the conventional system is that the operational
 vehicles are organized in teams based on past experience. Therefore, it is
 difficult to alter the organization of the team in an appropriate manner
 according to the severity of the current disaster. In addition, it is not
 possible to assign sufficient number of vehicles at specific locations
 such as crowded residential areas.
 Further, even if the report indicates that the disaster is considerably
 severe, there is a drawback that the number of operational vehicles cannot
 be increased easily. In other words, it is necessary to select additional
 vehicles one at a time from vehicles other than those organized at the
 vehicle organizing part 24.
 Also, when the disaster is considerably severe, since the remaining
 capability of the vehicles within the relevant region becomes too low, the
 operator demands assistance from other stations based on his/her
 experience. The demand of assistance is made based on human decision and
 not on a uniform decision criteria.
 Also, in the case of a more severe disaster, such as an earthquake, the
 head or the leading member of the station submits the demand for
 assistance to other geographically remote fire defense organizations by
 making a telephone call or by other communication means. Therefore,
 similarly, the demand for assistance is made based on human decision and
 not on a uniform decision criteria.
 SUMMARY OF THE INVENTION
 Accordingly, it is a general object of the present invention to provide a
 device, method and system for selecting vehicles to be sent to the
 location of disaster which can solve the problems above.
 It is another and more specific object of the present invention to provide
 a device, method and system for automatically selecting vehicles to be
 sent upon occurrence of a disaster, which may be a fire, according to the
 state of the disaster and to the disaster handling ability of the vehicle.
 In order to achieve the above objects according to the present invention, a
 device for selecting vehicles to be sent to a site of a fire is provided,
 the device including:
 first means provided with a first table in which fire-extinguishing ability
 data and arrival time data for each vehicle are stored as numerical data,
 the arrival time data representing time required for the vehicle to arrive
 at the fire site, and a second table in which initial fire power data and
 fire-spreading rate data are stored as numerical data; and
 second means for deriving a relationship between total fire-extinguishing
 ability of vehicles and total fire-spreading power of the fire with
 respect to time, and for selecting vehicles to be sent to the fire site
 based on the relationship.
 With the device described above, since the vehicle table and the
 fire-spreading condition table, or a disaster condition table are
 provided, a relationship between total fire-extinguishing ability of
 vehicles and total fire-spreading power of the fire with respect to time
 can be derived. Thereby, the change of condition of the disaster, or fire,
 can be understood accurately, so that an optimal vehicle selection is
 achieved in accordance with the change of condition of the disaster.
 Other objects and further features of the present invention will be
 apparent from the following detailed description when read in conjunction
 with the accompanying drawings.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
 In the following, principles and embodiments of the present invention will
 be described with reference to the accompanying drawings.
 FIG. 2 is a schematic diagram of an emergency command control system 1 of
 one embodiment of the present invention. An emergency call, which may be a
 telephone call, from a reporter is supplied to a command center 100 via a
 command control device 102 and then received at a command controller 104.
 Upon receipt of the emergency call at the controller 104, the operator
 connects the line to the reporter so as to obtain information about the
 type of the disaster, location of the disaster, and the affected object.
 For example, if the type of disaster is a fire, the address, the affected
 object (name of the affected building or forest) and fire-spreading
 information is obtained. The operator then inputs thus-obtained
 information into the command controller 104. The data input in the command
 controller 104 is supplied to a vehicle-selecting device 120 within the
 command controller 104.
 FIG. 3 is a schematic diagram of the vehicle-selecting device 120 of an
 embodiment of the present invention. In the present embodiment, the
 vehicle-selecting device 120 is included in the command controller 104,
 but is not limited to such a location. The vehicle selecting device 120 of
 FIG. 3 includes a man-machine interface 22, a command producing part 26, a
 nearest vehicle table producing part 122, an affected object fire-spread
 data determining part 124, a vehicle organizing part 126, a vehicle
 evaluation table 128, an affected object file 130, and a fire-spreading
 condition table 132.
 When the operator inputs data related to information about the type of the
 disaster, the location of the disaster, and the affected object via the
 command controller 104, the data is supplied to the vehicle selecting
 device 120 via the man-machine interface 22. Upon receipt of the data
 input supplied through the man-machine interface 22, the nearest vehicle
 table producing part 122 produces a nearest vehicle table. The nearest
 vehicle table is organized such that the vehicle data is arranged in an
 ascending order of the distance between the station to which the vehicle
 belongs and the location of the disaster.
 Also, the nearest vehicle table producing part 122 accesses a vehicle
 management part 12 in a vehicle management device 10 so as to obtain
 information related to the status of the vehicles. Any vehicle occupied at
 another disaster is deleted from the nearest vehicle table. Thus, the
 vehicle evaluation table 128 is produced.
 FIG. 4 is a diagram showing an example of the vehicle evaluation table 128.
 In the following description, the disaster is assumed to be a fire
 disaster. The vehicle evaluation table 128 includes numerical data for
 each vehicle such as fire-extinguishing ability W, unit fire-extinguishing
 power (per minute) .DELTA.W and arrival time (minutes) T.
 The fire-extinguishing ability W is understood as a limited value (or
 unlimited time) of the fire-extinguishing ability of the vehicle and is
 equivalent to the available amount of water. If the water can be obtained
 from a river or from a large-capacity reservoir, the available amount of
 water is regarded as an infinite amount considering a typical time
 required for fire-extinguishing activity. However, the amount of water is
 limited if the vehicle is a specially equipped vehicle such as a tank-type
 vehicle. The fire-extinguishing ability W is determined based on the
 equipment of each vehicle and the condition of the location of the
 disaster.
 The unit fire-extinguishing power .DELTA.W is understood as
 fire-extinguishing ability (water discharge ability) per minute. The
 fire-extinguishing ability of a reference vehicle is defined as a unit
 value ("1") and other vehicles are evaluated based on the unit value. The
 unit fire-extinguishing power .DELTA.W is predetermined as an initial
 setting.
 The arrival time T is a period of time between the instant of report of the
 disaster and the time at which the vehicle can arrive at the field of the
 disaster and actually start discharging the water. The arrival time may be
 calculated using any one of known calculation methods.
 Also, when a specific vehicle is selected individually, it is possible to
 provide the specific vehicle as first data of the vehicle evaluation table
 128 and to select operational vehicles such that the specific data is
 always selected. Thereby, it is possible to select operational vehicles
 including the specific vehicle.
 The data input from the man-machine interface 22 is supplied to the
 affected object fire-spread data determining part 124 via the nearest
 vehicle table producing part 122. Then, using the affected object file 130
 and the fire-spreading information input by the operator, the affected
 object fire-spread data determining part 124 obtains an initial fire power
 F and a fire-spreading power .DELTA.F from the fire-spreading condition
 table 132.
 FIG. 5 is a diagram showing an example of the fire-spreading condition
 table 132. The fire-spreading condition table 132 includes numerical data
 for a severity level of the disaster, the initial fire power F for each
 affected object and the fire-spreading power .DELTA.F.
 The operator determines the severity level based on the fire-spreading
 information provided by the reporter. For example, level A corresponds to
 a state where the fire is spreading vigorously, level B corresponds to a
 state where the fire can be seen, and level C corresponds to a state where
 smoke can be seen. An appropriate number of levels may be determined for
 each fire station.
 Also, the initial fire power F is determined using the affected object file
 (e.g., skyscrapers, houses and vehicles) and the severity level. The
 initial fire power F is predetermined based on the fire-extinguishing
 ability W shown in FIG. 4. The fire-spreading power .DELTA.F is a
 fire-spreading power per minute which is determined using the affected
 object file and the severity level. For example, for a level B fire of a
 house, the initial fire power F equals 5 and the fire-spreading power
 .DELTA.F equals 0.4.
 The vehicle-selecting device 120 may be extended to include other types of
 affected objects (wooden houses, strong houses, forests, etc.) by adding
 to or editing the affected object file 130. If the state of spreading of
 the fire is more severe than expected, the case may be easily handled by
 recalculating for a higher severity level.
 Then, the vehicle organizing part 126 organizes the vehicles using the
 vehicle evaluating table 128, the initial fire power F and the
 fire-spreading power .DELTA.F. The vehicle organizing process implemented
 by the vehicle organizing part 126 will be described with reference to
 FIGS. 6 to 8.
 FIG. 6 shows a timing chart of an example of the vehicle organizing
 process. In FIG. 6, the horizontal axis represents time t (minutes). A
 fire disaster is reported at Ts (t=0). In the present embodiment, vehicles
 A to D are sent out from the fire station. The vehicles A to D arrive at
 the field of the disaster at T1 to T4,respectively. In other words, T1 to
 T4 are instants at which the vehicles A to D start discharging the water.
 It is to be noted that any fire-extinguishing agent other than water may
 also be used. As a result of the water discharging operation by the
 vehicles, the fire is extinguished at Te. .DELTA.T is a time period
 between Te and a certain time Tm before Te. It is assumed that the water
 discharge operation by the vehicle arriving during the time period
 .DELTA.T does not contribute to extinguishing the fire.
 As an example, for a fire reported at time Ts to be extinguished at Te, the
 following relationship should be satisfied:
EQU (Total fire-extinguishing ability of the vehicles at time t).gtoreq.(Total
 fire-spreading power of the fire at time t) Equation (1).
 Also, the total fire-spreading power of the fire at time t satisfies the
 following equation (2).
 (Total fire-spreading power of the fire at time t)
EQU =F+.DELTA.F.times.time t Equation (2).
 The vehicles having arrived before time t are taken into account when
 calculating the total fire-extinguishing ability of the vehicles at time
 t. That is to say, the vehicles satisfying the following equation (3) are
 taken into account when calculating the total fire-extinguishing ability.
EQU Arrival time Tx-time t&lt;0, (x=1 to 4) Equation (3).
 Also, if the vehicle has already arrived at the field of disaster, that is
 to say if equation (3) is satisfied and if the following equation (4) is
 satisfied, the fire-extinguishing ability at time t for each vehicle W(t)
 satisfies the following equation(5).
EQU (t-Tx).times.unit fire-extinguishing power .DELTA.Wx &lt;fire-extinguishing
 power
EQU Wx, (x=1 to 4) Equation (4).
EQU fire-extinguishing power Wx(t)=(t-Tx).times.unit fire-extinguishing power
 .DELTA.Wx, (x=1 to 4) Equation (5).
 Also, if the vehicle has already arrived at the field of disaster, that is
 to say if equation (3) is satisfied and the following equation (6) is
 satisfied, the fire-extinguishing ability at time t for each vehicle W(t)
 satisfies the following equation (7).
EQU (t-Tx).times.unit fire-extinguishing power .DELTA.Wx &lt;fire-extinguishing
 power Wx, (x=1 to 4) Equation (6).
EQU fire-extinguishing power Wx(t)=fire-extinguishing power Wx, (x=1 to 4)
 Equation (7).
 Also, if the vehicle has not yet arrived at the field of disaster, that is
 to say if equation (3) is not satisfied, the fire-extinguishing ability at
 time t for each vehicle W(t) satisfies the following equation (7).
EQU fire-extinguishing power Wx(t)=0 Equation (8).
 Therefore, the total fire-extinguishing ability of the vehicle after t
 minutes can be expressed by the following equation (9).
EQU Total fire-extinguishing ability of the vehicle after t minutes=
 ##EQU1##
 In equation (9), N is the total number of operational vehicles.
 FIG. 7 shows a chart used for explaining the transitions of the states of
 the timing chart shown in FIG. 6. FIG. 7 is a chart including time t,
 arrived vehicles, fire-extinguishing time Te, and whether the relationship
 Te-t &lt;.DELTA.T is true or false. FIG. 7 will be described using the
 above equations (1) to (9).
 When time t=3, vehicle A has arrived at the field of disaster and has
 started discharging water. However, because the total fire-extinguishing
 ability is less than the total fire-spreading power of the fire, the
 fire-extinguishing time Te cannot be derived.
 At time t=4, vehicle B has also arrived at the field of disaster and has
 started discharging water. Therefore, since the total fire-extinguishing
 ability becomes greater than the total fire-spreading power of the fire,
 the fire-extinguishing time Te4 is derived. However, the relationship Te-t
 &lt;.DELTA.T is still not satisfied.
 At time t=6, vehicle C has also arrived at the field of disaster and has
 started discharging water. Therefore, since the total fire-extinguishing
 ability becomes greater than at time t=4, the fire-extinguishing time Te6
 is derived. The relationship Te-t&lt;.DELTA.T is now satisfied.
 Accordingly, vehicles A, B and C are selected as operational vehicles.
 Also, at time t=7, vehicle D has also arrived at the field of disaster.
 However, since time t=7 is within the time period .DELTA.T, it is
 determined that the water discharging operation of the vehicle D does not
 contribute to extinguishing the fire. Therefore, vehicle D is not selected
 as an operational vehicle.
 FIG. 8 shows a chart similar to FIG. 7 but including two or more vehicles
 arriving at the same instant. In order to deal with such a case, the
 vehicles are arranged in a priority order. When two or more vehicles
 arrive at the same instance, the calculation is made according to the
 priority in a descending order. That is to say, firstly, the vehicle
 having the highest priority is calculated.
 At time t=6, vehicles C and D have also arrived at the field of disaster
 and have started discharging water. In this embodiment, the priority of
 vehicle C is higher than the priority of vehicle D.
 Then, firstly, the calculation is carried out for vehicle C having the
 higher priority. As a result of the calculation, the fire-extinguishing
 time Te6 and the relationship Te-t&lt;.DELTA.T are obtained. Thus, since
 the relationship Te-t&lt;.DELTA.T is satisfied for the first time, the
 vehicles A, B and C are selected as operational vehicles. Since it is
 regarded that the water discharging operation of vehicle D does not
 contribute to extinguishing the fire, vehicle D is not selected as an
 operational vehicle.
 As has been described with reference to FIGS. 6 to 8, the operational
 vehicles are selected at the vehicle-selecting device 120.
 Referring now to FIG. 9, fire-spreading condition will be described for a
 case in which the vehicles are selected at the vehicle-selecting device
 120.
 FIG. 9 illustrates an example of a graph of the condition of the fire with
 respect to time. Line (1), indicated by a solid line and a broken line
 extending therefrom, is determined by the initial fire power F and the
 fire-spreading power .DELTA.F. If no vehicle arrives at the field of fire,
 as shown by the broken line, the fire will keep spreading.
 Line (2), indicated by a solid line and a broken line extending therefrom,
 represents a case where vehicle A has arrived at the field of fire at time
 t=2 and has started discharging water. Line (2) shows a reduced rate of
 spreading of the fire. However, as shown by the broken line, the fire is
 still spreading.
 Line (3), indicated by a solid line and a broken line extending therefrom,
 represents a case where vehicle B has arrived at the field of fire at time
 t=5 and has started discharging water. Line (3) shows a further reduced
 rate of spreading of the fire. However, as shown by the broken line, the
 fire is still spreading.
 Line (4), indicated by a solid line and a broken line extending therefrom,
 represents a case where vehicle C has arrived at the field of fire at time
 t=10 and has started discharging water. In this case, the fire starts
 getting smaller. The fire extinguishes at about time t=42.
 Line (5), indicated by a solid line and a broken line extending therefrom,
 represents a case where vehicle D has arrived at the field of fire at time
 t=15 and has started discharging water. In this case, the fire is further
 reduced. The fire extinguishes at about time t=29.
 Line (6), indicated by a solid line and a broken line extending therefrom,
 represents a case where vehicle E has arrived at the field of fire at time
 t=16 and has started discharging water. In this case, the fire is again
 further reduced. The fire extinguishes at about time t=22.
 By observing such a graph, the operator can easily understand the condition
 from the reported instant until the instant at which the fire is
 extinguished. If necessary, assistance information for adding or deleting
 the vehicles can be obtained.
 Referring again to FIG. 3, the vehicle organizing part 126 selects
 operational vehicles and announces the selection to the vehicle management
 part 12. Thus, the operational vehicles are reserved. The operational
 vehicle data is stored in a vehicle management table 14 so that the
 reserved operational vehicles will not be used for other disasters.
 Upon receipt of the announcement from the vehicle management part 12
 announcing that the operational vehicles have been reserved, the vehicle
 organizing part 126 instructs the command producing part 26 to produce a
 command. Then, the command producing part 26 produces the command and
 sends it as electronic data to a station 200 where the selected
 operational vehicle belongs and to the selected operational vehicle 212.
 The command includes data such as a type of the disaster, an address,
 affected objects, operational vehicles, and a map.
 At the station 200 where the selected operational vehicle belongs, a
 command tone, a voice signal and the command are output from output means
 such as a terminal display of a station terminal 204 and a printer 206.
 Also, a command tone and a voice signal are sent to the selected
 operational vehicle 212. The command center 100 and the station 200 are
 connected by connections such as a WAN 300 via routers 108 and 202 of the
 command center 100 and the station 200, respectively, or an audio line.
 The audio line is connected to a receiving telephone 208 which is in turn
 connected to a speaker 210.
 In the case of a fire, the operational vehicle is sent to the location of
 the fire, causing the fire-extinguishing ability of the station to which
 the operational vehicle belongs and the nearby stations to be reduced.
 This may cause a problem in the case of an occurrence of another disaster.
 The vehicle-selecting device 120 produces an available fire-extinguishing
 power table as shown in FIG. 10, and demands assistance from other
 stations according to the available fire-extinguishing power table. The
 available fire-extinguishing power table includes available
 fire-extinguishing power, occupied fire-extinguishing power, upper limit
 fire-extinguishing power, lower limit fire-extinguishing power and
 excessive fire-extinguishing power for each station.
 The available fire-extinguishing power is a sum of fire-extinguishing power
 of all vehicles belonging to each station and can be calculated
 automatically. The upper limit fire-extinguishing power is an upper-limit
 value of the fire-extinguishing power which may be used as assistance for
 other stations. For example, station 2 is capable of sending Wf2 as
 assistance for other stations as given by the following equation (10):
EQU W2-Wmax2=Wf2, Equation (10),
 where W2 is the available fire-extinguishing power, Wmax is the upper limit
 fire-extinguishing power and Wf2 is the excessive fire-extinguishing
 power.
 The lower limit fire-extinguishing power is an upper-limit value of the
 fire-extinguishing power assistance required from other stations. The
 occupied fire-extinguishing power is the fire-extinguishing power
 currently sent to the location of the disaster according to the command.
 The excessive fire-extinguishing power is a numerical value representing
 an excessive amount of the fire-extinguishing power enabling sending the
 operational vehicle for assisting another station. For station 1, the
 excessive fire-extinguishing power can be calculated by the following
 equations (11) and (12).
EQU Remaining fire-extinguishing power of station 1 =W1-Wt1, Equation (11),
 where W1 is the available fire-extinguishing power and Wt1 is the occupied
 fire-extinguishing power.
EQU Excessive fire-extinguishing power=Remaining fire-extinguishing power of
 station 1-Wmin1, Equation (12),
 where Wmin1 is the lower-limit fire-extinguishing power.
 If the value of the excessive fire-extinguishing power calculated from
 equation (12) is negative, assistance is required from other stations. If
 there is any station requiring assistance from other stations, a station
 having a positive value for the excessive fire-extinguishing power is
 automatically selected. The vehicle can be sent from the thus-selected
 station.
 In the case of a very severe disaster such as an earthquake, the remaining
 capability of the fire department (of the entire city) may decrease or
 there may be a shortage of the fire-extinguishing power. In such a case,
 the available fire-extinguishing power table of FIG. 10 is extended to the
 entire fire department so that assistance can be demanded from other fire
 organizations.
 FIG. 11 is a diagram showing an available fire-extinguishing power table
 which numerically shows the decision of demanding assistance from other
 fire organizations. The available fire-extinguishing power table of FIG.
 11 includes available fire-extinguishing power, occupied
 fire-extinguishing power, upper limit fire-extinguishing power, lower
 limit fire-extinguishing power and excessive fire-extinguishing power for
 each station and for a fire department (i.e., total of all stations in the
 fire department).
 As has been described with reference to FIG. 10, if the excessive
 fire-extinguishing power of the fire department Wf is positive, the fire
 department is capable of sending assistance vehicles to other fire
 organizations. The vehicles to be sent are selected such that the
 excessive fire-extinguishing power does not take a negative value.
 If the excessive fire-extinguishing power of the fire department Wf is
 negative, the fire department may demand assistance vehicles from other
 fire organizations. In this case, if there is a need to consult with the
 head of the fire department, the excessive fire-extinguishing power of the
 fire department Wf takes a negative value. Then, a warning may be
 outputted when the head of the fire department decides to demand
 assistance from other fire departments.
 Further, the present invention is not limited to these embodiments, but
 variations and modifications may be made without departing from the scope
 of the present invention.
 The present application is based on Japanese priority application No.
 11-249223 filed on Sept. 2, 1999, the entire contents of which are hereby
 incorporated by reference.