WO2013171798A1

WO2013171798A1 - Gateways and earthquake detection method

Info

Publication number: WO2013171798A1
Application number: PCT/JP2012/003253
Authority: WO
Inventors: 伊豆　哲也; 由美酒見
Original assignee: 富士通株式会社
Priority date: 2012-05-17
Filing date: 2012-05-17
Publication date: 2013-11-21
Also published as: JP5949909B2; JPWO2013171798A1

Abstract

[Problem] The purpose of this gateway is to improve determination accuracy when determining whether an earthquake has occurred within an area managed by the gateway by way of statistically processing vibration-related information from managed nodes when. [Solution] This gateway manages a plurality of nodes present in an area and has: a receiving unit that receives from at least some of the plurality of nodes vibration information about vibrations detected by the at least some of the plurality of nodes, and that receives from another gateway device earthquake information about whether an earthquake has occurred in another area managed by the other gateway device; a control unit that references the earthquake information for another area and determines whether there is an earthquake in the area; and a transmitting unit that, when an earthquake occurs in the area, transmits control information for when an earthquake occurs to the at least some of the nodes that transmitted the vibration information.

Description

Gateway and earthquake detection method

The technology disclosed in this specification relates to a technology in which a gateway detects an earthquake.

In a network system, when an earthquake occurs, there is a technique in which each base station transmits information related to the occurrence of the earthquake to each terminal. The network system is a system including a plurality of terminals and a plurality of base stations. For example, a base station installed for each area receives an earthquake alarm from an earthquake alarm device, and distributes information related to an earthquake to terminals existing under each base station (for example, Patent Document 1).

In addition, as a technology to detect the occurrence of earthquakes, when the acceleration sensor of the meter-reading meter detects shaking information, it sends shaking information to the surrounding meter-reading meters, and each metering meter statistically processes the received shaking information, There is a technique for determining the occurrence of an earthquake (for example, Patent Document 2).

Here, there is an ad hoc network system as a kind of network system. An ad hoc network is a type of self-configuring network that is linked by wireless communication. The ad hoc network includes a plurality of nodes having a wireless communication function, a gateway, and a management server. Each node in the ad hoc network transmits and receives packets by multi-hop communication. Multi-hop communication is a technology that enables communication even between nodes that are not within the communication range of each other, via another node that is within the communication range of each node.

For example, as a system using an ad hoc network, there is a meter-reading system that collects the power consumption of each home via the ad hoc network by incorporating a node capable of wireless communication into the power meter of each home. In the meter-reading system, a packet including the power consumption amount of each home detected by each power meter is transferred from each node included in each home power meter to the management server of the power company via the gateway.

JP 2005-309993 A JP 2008-139269 A

In an ad hoc network, it is required to appropriately control each node by transmitting some information to each node when an earthquake occurs. For example, depending on the occurrence of an earthquake, it is necessary to cancel a predetermined state of each node or to transition each node to a predetermined state.

Therefore, by applying the technology of Patent Document 1 to the ad hoc network system, the management server notifies the gateway of the occurrence of an earthquake when receiving an earthquake alarm from an external device. Then, it is conceivable that the gateway that has received the notification performs control on the managed node.

However, if a problem occurs in communication between the management server and an external device, or if the management server fails due to an earthquake, the node cannot be controlled by the gateway.

Therefore, for example, by applying a technique such as Patent Document 2 to an ad hoc network system, the occurrence of an earthquake can be detected based on the detection result of the acceleration sensor at each node. For example, it is conceivable that each node is provided with an acceleration sensor, and each gateway performs statistical processing on shake information from each node, and each gateway detects the occurrence of an earthquake.

Here, in the ad hoc network system, a plurality of gateways manage different ad hoc networks. A plurality of nodes included in each ad hoc network form an ad hoc network area in which at least some areas are different from each other. Each ad hoc network area is set regardless of requirements related to earthquakes such as ground strength, and naturally, is set regardless of earthquake occurrence areas that are difficult to predict.

Therefore, when the technology of Patent Document 2 is applied, even when the gateway that manages each ad hoc network area determines that no earthquake has occurred, there may actually be an earthquake within the area. For example, there is a case where some areas in the ad hoc network area are greatly shaken and the shake is small in other areas due to the strength of the ground or the difference in seismic intensity at each place. Thus, when there are nodes that detect shaking and nodes that do not detect, each gateway cannot accurately detect the occurrence of an earthquake in each ad hoc network area.

Therefore, in the present invention, the gateway aims to increase the accuracy of the determination when determining whether or not an earthquake has occurred in the area under the management of the gateway by statistically processing information related to vibration from the managed node. And

According to an aspect of the present invention, there is provided a gateway that manages a plurality of nodes existing in an area, and vibration information relating to vibrations detected in the at least some nodes from at least some of the plurality of nodes. A control unit that determines the presence or absence of an earthquake in the area based on the vibration information, and a transmission unit that transmits earthquake information including a result of determination by the control unit to another gateway device, Have

According to another aspect of the present invention, there is provided a gateway for managing a plurality of nodes existing in an area, the vibration relating to the vibration detected in the at least some nodes from at least some of the plurality of nodes. Receiving information and receiving from the other gateway device earthquake information regarding the occurrence of an earthquake in another area managed by the other gateway device, and referring to the earthquake information in the other area, A control unit that determines the presence or absence of an earthquake in the area; and a transmission unit that transmits control information when an earthquake occurs to the at least some nodes that transmitted the vibration information when there is an earthquake in the area; Have

According to one aspect of the present invention, the gateway can share the determination result of the occurrence of the earthquake with other gateways. Furthermore, in the shared gateway, the occurrence of an earthquake can be determined with higher accuracy by determining the occurrence of the earthquake in consideration of the earthquake information.

FIG. 1 is an explanatory diagram of an example of the ad hoc network system according to the embodiment. FIG. 2 is a functional block diagram of the node N. FIG. 3 is a diagram illustrating a data configuration example of the control packet. FIG. 4 is a diagram illustrating a data configuration example of the vibration data packet. FIG. 5 is a functional block diagram of the gateway GW. FIG. 6 is a diagram illustrating a data configuration example of the sharing destination table. FIG. 7 is a process flowchart executed by the node N. FIG. 8 is a process flowchart executed by the gateway GW. FIG. 9 is another flowchart of processing executed by the gateway GW. FIG. 10 is a hardware configuration example of the node N. FIG. 11 is a hardware configuration example of the gateway GW.

Exemplary embodiments of a gateway, a gateway earthquake detection method, a gateway earthquake detection program, and an ad hoc network system according to the present embodiment will be described below in detail with reference to the accompanying drawings.
Example 1
FIG. 1 is an explanatory diagram of an example of the ad hoc network system according to the embodiment. The ad hoc network system in the present embodiment includes a plurality of nodes N, a plurality of gateways GW, and a management server S. First, an ad hoc network and packet transfer in the ad hoc network will be described with reference to FIG.

The ad hoc network system includes a management server S, gateways GW1, GW2, and GW3, and nodes NA to NT. The ad hoc network system may include a gateway and a node other than those shown in the figure.

The management server S and the gateways GW1, GW2, and GW3 are connected via a normal network 200 such as the Internet, LAN, or WAN. Further, the gateway communicates with a node under management via an ad hoc network. In the example of FIG. 1, the gateway GW1 is connected to the nodes NA to NH via the ad hoc network 100. The gateway GW2 communicates with the nodes NI to NP via the ad hoc network 101. The gateway GW3 communicates with the nodes NQ to NT via the ad hoc network 102. Hereinafter, the gateway GW will be described using the gateway GW1.

The gateway GW1 is a relay device that connects the ad hoc network 100 and the normal network 200. The gateway GW1 can transmit and receive both the protocol format information of the ad hoc network 100 and the protocol format information of the normal network 200.

In addition, the gateway GW1 performs communication transfer by converting the protocol of information between the ad hoc network 100 and the normal network 200. For example, a packet transmitted from each node NA to NH in the ad hoc network 100 to the management server S is protocol-converted by the gateway GW1. Thereafter, the gateway GW1 transfers the packet to the normal network 200, whereby the management server S receives necessary information.

Further, information transmitted from the management server S to each of the nodes NA to NH is subjected to protocol conversion by the gateway GW1 and transferred as a packet from the gateway GW1 to each node in the ad hoc network 100.

In the ad hoc network 100, a plurality of nodes N are provided. In FIG. 1, nodes NA to NH are shown as representatives. Similarly, in the ad

hoc networks

101 and 102, a plurality of nodes are provided in each ad hoc network. In FIG. 1, nodes NI to NP and nodes NQ to NT are shown as representatives. In the following, the node N will be described using the nodes NA to NH in the ad hoc network 100. Furthermore, when it is not necessary to distinguish each node, it demonstrates as the node N. FIG.

Each node N is a device capable of multi-hop communication with other nodes that can communicate within a predetermined communication range. In the ad hoc network 100, it is not necessary that all the nodes NA to NH can directly communicate with the gateway GW1, and each node NA to NH communicates with the gateway GW1 via other nodes. Therefore, in the ad hoc network 100, it is only necessary that some nodes N can communicate with the gateway GW1. In FIG. 1, nodes that can directly communicate with the gateway GW1 are assumed to be nodes NA and ND.

Each node NA-NH generates a routing table individually. Each node NA to NH generates a routing table by communicating a hello packet with surrounding nodes. The hello packet is a packet for sharing the presence of the own device and a communication key, and is a packet broadcast from one node to another node.

The routing table is generated using a conventional method. When each node generates a routing table, for example, even when a certain node becomes unable to communicate and cannot transfer a packet, another transfer path can be set.

In FIG. 1, it is assumed that four routes are set by the nodes NA to NH constituting the ad hoc network 100. Specifically, a route including the node NC, the node NB, the node NA, and the gateway GW1, a route including the node NE, the node ND, and the gateway GW1, a route including the node NG, the node NF, the node ND, and the gateway GW1, A route including the node NH, the node NF, the node ND, and the gateway GW1 is set.

Here, a node close to the gateway GW1 is called an upstream node. Depending on the scale of the ad hoc network 100, the node NB and the node NE are also upstream nodes. When data is transmitted from each node NA to NH to the management server S, each node NA to NH transmits the detected data to the gateway GW1 according to the routed route.

In the ad hoc network system of this embodiment, each node NA to NH encrypts payload data in a packet using an encryption key for security. Encryption ensures packet confidentiality.

For further security improvement, each node NA to NH may generate a message authentication code (MAC) and add it to each packet. By verifying the MAC value, the integrity of the data is verified, and the validity of the node that generated the MAC is verified. When generating the MAC, a key for generating the MAC is used.

The calculated MAC values are the same for the same data content with the same MAC key. In other words, the MAC values calculated with different MAC keys and the MAC values calculated for different data contents are not the same. Therefore, by verifying the MAC value in the process of multi-hop communication, the node N and the gateway GW1 can detect a packet with incomplete data or a packet generated by a node that may be illegal.

As described above, secure communication of the ad hoc network 100 is ensured by using various keys. The encryption key and the MAC generation key are stored in the storage areas of the nodes NA to NH.

In the present embodiment, each of the nodes NA to NH further includes an acceleration sensor that detects vibration, thereby detecting vibration in the own device. Then, the gateway GW1 collects vibration information detected at each of the nodes NA to NH. The vibration information is information related to vibration transmitted from each node. Based on the vibration information, the gateway GW1 determines the occurrence of an earthquake in the area of the ad hoc network 100.

When the gateway GW1 determines that an earthquake has occurred, the gateway GW1 performs the control necessary for the occurrence of the earthquake on each of the nodes NA to NH. That is, the gateway GW1 transmits control information to the nodes NA to NH when an earthquake occurs. The control information is information for causing each node to perform control during an earthquake.

Also, when it is determined whether there is an earthquake in the gateway GW1, the determination result is shared with other gateways. The other gateway is a gateway that manages an ad hoc network area around the gateway GW1. For example, the gateway GW2 that manages the area adjacent to the gateway GW1 receives the determination result sharing from the gateway GW1.

Therefore, even if the occurrence of an earthquake in the area of the ad hoc network 101 managed by the other gateway GW2 cannot be detected only by the vibration information of the plurality of nodes NI to NP managed by the other gateway GW2, it is shared from the gateway GW1. The occurrence of an earthquake can be detected based on the information. As a result, the other gateway GW2 can perform necessary control on the nodes NI to NP when an earthquake occurs.

Here, an example of control necessary when an earthquake occurs will be described. Each node N stores information such as an encryption key and a MAC generation key in its own storage area in order to establish secure communication by encryption or MAC verification. In other words, each node N holds secret information in a storage area that should not be leaked to a third party. On the other hand, since it is conceivable that a malicious third party illegally obtains secret information by stealing a node, anti-theft measures are required. Therefore, when vibration is detected by the acceleration sensor, each node N may determine that there is a possibility of theft and perform control for preventing leakage of secret information. For example, each node N activates a timer when vibration is detected, and erases secret information after a predetermined time has elapsed.

However, when the detected vibration is an earthquake-induced vibration, it is not necessary to delete the secret information. Therefore, when the gateway GW detects the occurrence of an earthquake, by controlling each node N when the earthquake occurs, each node N stops the timer and prevents secret information from being erased. Can do.
In addition, the ad hoc network system of the present embodiment is applied to a meter reading system that collects the amount of power used in each home. In the meter reading system, personal information such as the amount of electricity used is stored in the storage area in addition to the encryption key and the key for generating the MAC. Along with the detection of vibration, processing for preventing leakage of confidential information including personal information is started, and when the vibration is caused by an earthquake, the processing can be canceled.

In the example of FIG. 1, one gateway GW1 is provided in the ad hoc network 100, but a plurality of gateways may be provided in one ad hoc network 100. In addition to collecting power usage, this ad hoc network system can also be used to investigate the environment, for example, by providing each node with a sensor function that detects temperature, humidity, light intensity, etc. is there.

Here, in the ad hoc network system according to the present embodiment, the gateway GW1 communicates with a plurality of nodes NA to NH to determine whether there is an earthquake in the area of the ad hoc network 100. Furthermore, the gateway GW1 determines the presence / absence of an earthquake in the area of the ad hoc network 100 using the determination result in another gateway. If the gateway GW1 determines that an earthquake has occurred, the gateway GW1 performs some control on the nodes NA to NH.

Next, the functional configuration of the node N will be described. FIG. 2 is a functional block diagram of the node N. Hereinafter, each of the nodes NA to NT will be described as a node N, and each of the gateways GW1 to GW3 will be described as a gateway GW.

The node N includes a communication unit 11, a detection unit 12, a control unit 13, an acquisition unit 14, and a storage unit 15. The communication unit 11 is a processing unit that communicates with other devices. For example, the communication unit 11 exchanges packets with other nodes N. In addition, the communication unit 11 in some nodes N communicates with the gateway GW.

Here, the packet flowing through the ad hoc network includes a broadcast packet and a unicast packet. In the present embodiment, the broadcast packet includes, for example, a control packet generated by the gateway GW and a hello packet. Note that the control packet may be unicast to a specific node.

Also, the unicast packet includes, for example, a data packet including detection data detected at each node. In the present embodiment, the data packet further includes a vibration data packet including detection data by the acceleration sensor and a normal data packet including detection data by a sensor other than the acceleration sensor. The vibration data packet is a kind of the vibration information.

The detection unit 12 is a processing unit that detects the vibration of the node N. For example, the detection unit 12 receives an output from an acceleration sensor included in the node N and detects vibration. Note that information indicating that vibration has been detected may be output to the control unit 13 only when the output from the acceleration sensor is equal to or greater than a predetermined value.

The control unit 13 is a processing unit that receives the output from the detection unit 12 to generate vibration information and controls the state of the node N. For example, the control part 13 performs control at the time of an earthquake, when the control packet which the gateway produced | generated is received.

In the present embodiment, the control at the time of an earthquake will be described on the assumption that the state of the node is control for canceling a warning state against theft. That is, when the detection unit 12 detects vibration, the control unit 13 shifts to a warning state against theft. Thereafter, when a control packet is received, the alert state is released.

The alert state is a state in which, for example, the elapsed time from vibration detection is monitored and secret information is deleted after a predetermined time has elapsed. Another example is a state where security for access to the storage device is set higher than the normal state.

Here, as described above, since each node stores secret information, there is a possibility that secret information may be leaked when the node is stolen. Therefore, when vibration is detected, it is effective to transition from the normal state to the alert state in consideration of the possibility of theft. However, it is not preferable that the alert state is continued when the detected vibration is not a vibration due to theft. For example, if secret information is erased, subsequent communication cannot be performed. Therefore, it is effective to release the alert state based on the control packet.

The acquisition unit 14 acquires detection data from a sensor or device included in the node N or an external sensor or device. Then, the acquisition unit 14 stores the detection data in the storage unit 15.

The storage unit 15 is a storage device that stores detection data. Furthermore, the storage unit 15 is a storage device that stores information about security such as an encryption key.

FIG. 3 is a diagram illustrating a data configuration example of the control packet. The control packet is a kind of control information. The control packet 3 is a packet for controlling a node when an earthquake occurs. A header information storage unit 31 and a payload data storage unit 32 are allocated to the control packet 3. The header information storage unit 31 stores header information. The header information includes a destination address, a local source address, a global source address, and a packet type.

The destination address is a special address dedicated to broadcasting. For example, the destination address is an address “255.255.255.255” prepared in advance. Each node receives a packet transmitted to an address set individually, but also receives a packet transmitted to the special address. That is, a packet in which a special address is set is received by all nodes that are in a range where communication with the device that transmitted the packet is possible.

The local transmission source address is information related to the address of a device that transmits a packet in one communication forming a multi-hop communication. The local transmission source address is rewritten to the address of the main device to be transmitted each time a packet is transmitted once during multi-hop communication.

The global source address is information related to the address of the device that generated the packet. That is, the global transmission source address is information related to the address of the device that is the starting point in multihop communication. In the case of the control packet 3, it is information relating to the address of the gateway that generated the control packet 3. The packet type is information indicating the type of the packet. For example, in the case of the control packet 3, “0” is set. Therefore, by referring to the packet type, the node N that has received the packet can grasp the type of the received packet.

Also, it is determined whether or not to forward the received packet to another node according to the packet type. For example, when the node N receives a packet in which a special address is set as the destination address and the packet type is “0”, the received control packet 3 is transferred to another node N. That is, the control packet is transferred through the network as a target of multihop communication.

On the other hand, for example, the packet type “1” is set in the hello packet broadcasted in the same manner as the control packet. When the node N receives a packet in which a special address is set as a destination address and the packet type is “1”, the received hello packet is not transferred to another node N. That is, the hello packet is excluded from the target of multi-hop communication, and the packet transfer converges at a certain node N.

Next, the payload data storage unit 32 stores payload data. The payload data is, for example, information indicating the content of control in the node or information obtained by encrypting header information. Further, when the control when receiving the control packet in advance is designated by each node, the payload data may be, for example, only information obtained by encrypting header information.

FIG. 4 is a diagram showing a data configuration example of the vibration data packet. The vibration data packet 4 is a packet for notifying the gateway GW of the vibration detected at the node N.

The vibration data packet 4 is assigned a header information storage unit 41 and a payload data storage unit 42, respectively. The header information storage unit 41 stores header information. The header information includes a local transmission source address, a local transmission destination address, a global transmission source address, a global transmission destination address, and a packet type.

The local source address, global source address, and packet type are the same information as the control packet 3. However, in the case of a vibration data packet, “2” is set as the packet type. The global transmission source address is set to the address of the node that generated the vibration data packet.

The local transmission destination address is information relating to the address of a device that is a transmission destination of a packet in one communication forming a multi-hop communication. The global destination address is information regarding the address of the device that finally receives the packet. That is, the global transmission destination address is information regarding the address of the gateway GW that is the end point when the vibration data packet 4 is subjected to multi-hop communication.

The payload data storage unit 42 stores payload data. The payload data is information including the acceleration value detected by the acceleration sensor, the detection time, and the like.

Although not described in detail here, the normal data packet has the same data configuration as the vibration data packet. However, detection data by other sensors is set in the payload data. When each node performs MAC verification, the normal data packet further includes a MAC value calculated by the MAC key.

Here, the control packet 3 may be transmitted only to the node that transmitted the vibration data packet. In this case, as in FIG. 4, header information including a global transmission destination address and a local transmission destination address is set in the control packet.

Next, the gateway will be described. FIG. 5 is a functional block diagram of the gateway GW. The gateway GW includes a communication unit 21, a control unit 22, and a storage unit 23.

The communication unit 21 communicates directly or indirectly with other devices. For example, the communication unit 21 transmits a control packet to a node capable of ad hoc communication. The communication unit 21 receives a vibration packet from each node N. Furthermore, the communication unit 21 transmits earthquake information to another gateway GW or receives earthquake information from another gateway.

Here, the communication unit 21 functions as a reception unit when receiving information, and functions as a transmission unit when transmitting information. Note that the communication unit 21 may include a plurality of communication units according to different communication protocols.

The earthquake information is information including a determination result of the presence or absence of an earthquake in the gateway GW. The other gateway GW is, for example, a gateway GW that manages an area that is geographically adjacent to the own gateway GW among areas of a plurality of ad hoc networks.

The control unit 22 is a processing unit that generates a control packet. The controller 22 determines the presence or absence of an earthquake based on the vibration packet. Moreover, the control part 22 produces | generates earthquake information based on the determination result of the presence or absence of an earthquake. Then, the control unit 22 refers to the sharing destination table 6, specifies the sharing destination, and causes the communication unit 21 to transmit the earthquake information. Furthermore, when earthquake information is received from another gateway GW, the presence / absence of an earthquake is determined based on the earthquake information.

The storage unit 23 stores a shared destination table 6 related to gateways that share earthquake information. FIG. 6 is a diagram illustrating a data configuration example of the sharing destination table 6. The share destination table 6 stores a share destination GW, a share destination address, and area information in association with each other.

The shared GW is information for identifying a shared gateway that transmits earthquake information. The sharing destination GW is set in advance by the management server S for each gateway. Note that the administrator of the management server S sets the sharing destination GW based on the positional relationship between the areas of the ad hoc network managed by each gateway.

The shared address is information on the address of the shared GW. The area information is information related to the area of the ad hoc network managed by the sharing destination GW. For example, an address and geographical range information are stored as area information. Information stored in the sharing destination table 6 is received from the management server S and stored in the storage unit 23.

Next, processing at the time of vibration detection in the node N will be described. FIG. 7 is a process flowchart executed by the node N. Independently of the process illustrated in FIG. 7, the node N transmits a normal data packet including detection data acquired by the acquisition unit 14 from various sensors to the ad hoc network. The normal data packet transfer process is the same as the conventional method.

The detection unit 12 receives the acceleration detected by the acceleration sensor from the acceleration sensor (OP.1). The detecting unit 12 determines whether or not the received acceleration is equal to or greater than a threshold (OP.2). If it is equal to or greater than the threshold, it is determined that vibration equal to or greater than the threshold has occurred in node N. The process proceeds to 3 (OP. 2 Yes). On the other hand, if the acceleration is less than the threshold (OP. 2 NO), the node N performs the process in OP. Return to 1.

The communication unit 11 transmits vibration information to the gateway GW under the control of the control unit 13 (OP.3). Furthermore, when vibration is detected, the control unit 13 activates a timer. In addition, the control unit 13 generates vibration information. Specifically, as shown in FIG. 4, various addresses are stored in the header information storage unit, and “2” is set as the packet type. The control unit 13 refers to the routing table and sets a local transmission destination address for transmitting the vibration data packet toward the gateway GW. Further, the control unit 13 stores information on the vibration detected by the detection unit 12 in the payload data storage unit.

Next, the control unit 13 determines whether the communication unit 11 has received control information (OP.4). There are cases where control information is received from the gateway GW and cases where it is received from another node N. When the control information is received (OP.4 YES), the control unit 13 performs predetermined control when an earthquake occurs (OP.6). The predetermined control may be control set in advance in the node N or may be control specified in the control information.

On the other hand, when the control information is not received (OP, 4NO), the control unit 13 determines whether or not a predetermined time has elapsed (OP.5). When the predetermined time has not elapsed (OP. 5 NO), the control unit 13 determines that OP. Return processing to 4. If the predetermined time has elapsed (YES in OP.5), the process is terminated.

As described above, each node N in the present embodiment can execute predetermined control when an earthquake occurs based on reception of control information.

In addition, when performing the control to release the warning state as the predetermined control when an earthquake occurs, first, the OP. 2, when detecting an acceleration equal to or higher than the threshold, the control unit 13 performs a process of causing the node N to transition to the alert state. When the communication unit 11 receives control information within a predetermined time, the control unit 13 cancels the alert state.

Therefore, it is possible to prevent a warning state for preventing leakage of confidential information from being continued even during an earthquake. Therefore, each node N temporarily transitions to the alert state, but can cancel the alert state if the vibration is caused by an earthquake. On the other hand, if the vibration is not caused by an earthquake, the alert state can be maintained. Therefore, the alert state for preventing leakage of secret information can be maintained against the vibration in the case of not being an earthquake.

Next, the earthquake determination process in the gateway GW will be described. FIG. 8 is a process flowchart executed by the gateway GW. Independently of the process shown in FIG. 8, the gateway GW performs a process of receiving a normal data packet from each node N and transferring it to the management server S. The normal data packet transfer process is the same as the conventional method.

The control unit 22 in the gateway GW determines whether or not the communication unit 21 has received vibration information (OP.10). When vibration information is received (OP.10 YES), the control unit 22 performs statistical processing on the received vibration information (OP.11). Each time the communication unit 21 receives vibration information, the received vibration information is stored in the memory.

In the statistical processing, for example, the control unit 22 counts the number of vibration information received. Further, when the position information of each node is included in the vibration information, the control unit 22 may generate a distribution of the nodes that generated the vibration information according to the position information. When the vibration information includes information related to the magnitude of vibration, the control unit 22 may generate a distribution of nodes that generated the vibration information according to the magnitude of vibration.

Next, the control unit 22 determines whether or not the statistical processing result satisfies the earthquake determination condition (OP.12). The earthquake determination condition is a condition for determining the presence or absence of an earthquake by being compared with the result of statistical processing.

For example, in statistical processing, when the number of vibration information receptions is counted, the earthquake determination condition is an integer indicating the lower limit value of the vibration information reception number or the lower limit value of the ratio to the total number of nodes. Further, when a distribution is generated by statistical processing, the earthquake determination condition is a distribution pattern. Hereinafter, the earthquake determination condition will be described as “50% or more with respect to the total number of nodes”.

When the earthquake determination condition is satisfied (YES in OP.12), the control unit 22 generates control information, and the communication unit 21 transmits the control information to each node N (OP.13). The control information may be broadcast to all nodes or unicast to a specific node.

For example, it is assumed that 100 nodes N are included in the ad hoc network managed by the gateway GW and that the number of vibration information received is 60 in the statistical processing. In this case, the control unit 22 determines that the earthquake determination condition (the number of receptions is 50% or more with respect to the total number of nodes) is satisfied. Then, the control unit 22 generates control information to be transmitted to each node N.

The control packet shown in FIG. 3 is generated as control information. The control unit 22 sets various addresses in the header information storage unit and sets “0” in the packet type. Furthermore, the control unit 22 stores information in the payload data storage unit as necessary.

Next, under the control of the control unit 22, the communication unit 21 transmits the earthquake information to the sharing destination GW (OP.14). That is, the gateway GW shares the earthquake determination result with the surrounding gateway GW. In this embodiment, the earthquake information is transmitted only when it is determined that an earthquake has occurred. However, the earthquake information may be transmitted regardless of the determination result. Then, the gateway GW ends a series of processes.

On the other hand, when the control unit 22 has not received the vibration information (OP. 10 NO), or when it is determined that the earthquake determination condition is not satisfied (OP. 12 NO), the control unit 22 performs other communication with the communication unit 21. It is determined whether the earthquake information from the gateway GW has been received (OP.15).

That is, when it is determined that an earthquake has occurred in another gateway GW and the own device is a shared destination GW in another gateway GW, the communication unit 21 of the own device Will be received from another gateway GW. In the present embodiment, when the gateway GW adjacent to the device detects the occurrence of an earthquake, the communication unit 21 receives the earthquake information.

When the earthquake information is received (OP.15 YES), the control unit 22 generates the control information and the communication unit 21 transmits the control information to each node (OP.16). Then, the gateway GW ends the process. On the other hand, when the earthquake information is not received (OP.15 NO), the gateway ends the process as it is.

Here, by receiving earthquake information, the gateway can detect that an earthquake has occurred in an adjacent ad hoc network area. Therefore, even when the occurrence of an earthquake cannot be detected by vibration information from a node in the ad hoc network managed by the gateway, the gateway can perform control at the time of the earthquake.

That is, each gateway can detect an earthquake when it is not possible to accurately detect the presence or absence of an earthquake only by the occurrence of vibration at a node in each ad hoc network area. For example, it is assumed that an earthquake that gives a vibration of the level detected by the detection unit 12 of the node N occurs in the area 1000 of FIG.

In this case, the gateway GW1 that manages the area of the ad hoc network 100 can detect the occurrence of the earthquake, but the gateway GW2 that manages the area of the ad hoc network 101 cannot detect the occurrence of the earthquake. Therefore, when the gateway GW1 shares the earthquake information with the gateway GW2, it is possible to control the nodes NI to NP included in the ad hoc network 101.

As described above, the gateway GW can share the determination result of the occurrence of the earthquake with other gateways. Furthermore, the shared gateway can determine the occurrence of an earthquake by taking earthquake information into account. Therefore, the presence or absence of an earthquake can be determined with higher accuracy.

(Example 2)
The gateway GW may perform the earthquake determination process with the process flow shown in FIG. FIG. 9 is another flowchart executed by the gateway. In addition, about the same processing content as the flowchart shown in FIG. 8, while attaching | subjecting the same code | symbol, description is abbreviate | omitted.

OP. Following the process of 11, the control unit 22 determines whether the result of the statistical process satisfies the first earthquake determination condition (OP.17). When the first earthquake judgment condition is satisfied (OP.17 YES), OP. Proceed to step 13. On the other hand, when the first earthquake determination condition is not satisfied (OP.17 NO), the control unit 22 determines whether earthquake information is received from another gateway GW (OP.15).

If the earthquake information has not been received from another gateway GW (OP.15 NO), the gateway ends the process. On the other hand, when earthquake information is received from another gateway GW (OP.15 YES), the control unit 22 determines whether the result of the statistical processing satisfies the second earthquake determination condition (OP.18). ). When the second earthquake determination condition is satisfied (OP.18 YES), the control unit 22 determines that the OP. 16 is executed.

Here, the difference between the first earthquake judgment condition and the second earthquake judgment condition will be described. The first earthquake determination condition is a stricter condition than the second earthquake determination condition. For example, the first earthquake determination condition is “50% or more of all nodes”, whereas the second earthquake determination condition is “10% or more of all nodes”.

As described above, when the gateway GW in the second embodiment does not satisfy the first earthquake determination condition, the gateway GW determines whether there is an earthquake based on the reception status of the earthquake information and the second earthquake determination condition. can do.

In addition, the presence or absence of an earthquake may be determined based on the content of the earthquake information. For example, when the gateway GW detects an earthquake, the gateway GW sets information indicating the difference between the earthquake determination condition and the statistical result in the earthquake information. Then, the gateway GW transmits the earthquake information to the sharing destination GW. The gateway GW that has received the earthquake information determines that an earthquake has occurred in the area of the ad hoc network managed by the gateway GW when the difference is equal to or greater than the threshold and the second earthquake determination condition is satisfied.

As described above, the gateway GW can share the determination result of the occurrence of the earthquake with other gateways. Furthermore, the shared gateway can determine the occurrence of an earthquake by taking earthquake information into account.
(Example 3)
FIG. 10 is a hardware configuration example of the node N. The node N includes a CPU (CENTRAL PROCESSING UNIT) 301, a RAM (RANDOM ACCESS MEMORY) 302, a flash memory 303, an interface (I / F) 304, an encryption circuit 305, a sensor 306, and a bus 307. I have. The CPU 301 to the sensor 306 are connected by a bus 307, respectively.

CPU 301 governs overall control of node N. The CPU 301 functions as the detection unit 12, the control unit 13, the acquisition unit 14, and the like by executing a program expanded in the RAM 302.

The RAM 302 is used as a work area for the CPU 301. The flash memory 303 stores key information such as a program, information detected by a sensor, and an encryption key. The flash memory 303 is an example of the storage unit 15. The I / F 304 transmits and receives packets by multi-hop communication. The I / F 304 is an example of the communication unit 11. The program includes, for example, a program for executing each process in the communication apparatus shown in the flowchart.

The encryption circuit 305 is a circuit that encrypts data using an encryption key when encrypting the data. For example, when the packet is encrypted and transferred, the encryption circuit 305 functions. When encryption is executed by software, the encryption circuit 305 is not necessary by storing a program corresponding to the encryption circuit 305 in the flash memory 303. The sensor 306 detects data unique to the sensor 306. For example, data suitable for the measurement target is detected, such as temperature, humidity, water level, precipitation, air volume, volume, power consumption, time, time, and acceleration.

Note that the node N may have the same configuration as a general-purpose computer. In other words, the computer functioning as the node N is a CPU (CENTRAL PROCESSING UNIT), ROM (READ ONLY MEMORY), RAM (RANDOM ACCESS MEMORY), communication device, HDD (HARD DISK DRIVE), input device, display device, medium reading device. A computer having the above may be used. Each unit is connected to each other via a bus.

FIG. 11 is a hardware configuration example of the gateway GW. The gateway GW includes a CPU (CENTRAL PROCESSING UNIT) 401, a ROM (READ ONLY MEMORY) 402, a RAM (RANDOM ACCESS MEMORY) 403, a communication device 404, an HDD (HARD DISK DRIVE) 405, an input device 406, a display device 407, a medium reading device. A device 408 is included, and each unit is connected to each other via a bus 409. Data can be transmitted and received between them under the control of the CPU 401. Note that the gateway GW does not have to have all the configurations shown in FIG.

The earthquake detection program for executing each process of the gateway GW shown in the flowchart is recorded on a computer-readable recording medium. Examples of the computer-readable recording medium include a magnetic recording device, an optical disk, a magneto-optical recording medium, and a semiconductor memory. Examples of the magnetic recording device include an HDD, a flexible disk (FD), and a magnetic tape (MT).

Optical discs include DVD (DIGITAL VERSATILE DISC), DVD-RAM, CD-ROM (COMPACT DISC-READ ONLY MEMORY), CD-R (RECORABLE) / RW (REWRITABLE), and the like. Magneto-optical recording media include MO (MAGNETO-OPTICAL DISK). When this program is distributed, for example, a portable recording medium such as a DVD or CD-ROM in which the program is recorded may be sold.

In the gateway GW, for example, the medium reading device 409 reads the program from the recording medium on which the program is recorded. The CPU 401 stores the read program in the HDD 405, the ROM 402, or the RAM 403.

The CPU 401 is a central processing unit that controls operation of the entire gateway GW. The communication device 404 receives signals from the node N, the management server S, etc. via the network, and passes the contents of the signals to the CPU 401. The communication device 404 is an example of the communication unit 21. Further, the communication device 404 transmits a signal to the node N or the like in response to an instruction from the CPU 401.

The HDD 405 stores a program that causes a computer to execute each process shown in the flowchart. The CPU 401 reads out the program from the HDD 405 and executes it to function as the control unit 22 shown in FIG. The program may be stored in the ROM 402 or the RAM 403 that can be accessed by the CPU 401.

Further, information is stored in the HDD 405 under the control of the CPU 401. Similar to the program, information may be stored in the ROM 402 or RAM 403 accessible to the CPU 401. That is, the data table described as being stored in the storage unit 23 is stored in a storage device such as the HDD 405, the ROM 402, or the RAM 403. The input device 406 receives data input under the control of the CPU 401. The display device 407 displays each information.

S management server GW gateway N node 11 communication unit 12 detection unit 13 control unit 14 acquisition unit 15 storage unit 21 communication unit 22 control unit 23 storage unit

Claims

A gateway that manages multiple nodes in an area,
A receiving unit that receives vibration information related to vibration detected in at least some of the nodes from at least some of the plurality of nodes;
A control unit for determining the presence or absence of an earthquake in the area based on the vibration information;
The gateway characterized by having the transmission part which transmits the earthquake information containing the determination result by the said control part to another gateway apparatus.
The gateway according to claim 1, wherein the control unit determines the presence or absence of an earthquake based on the number of received vibration information.
The said transmission part further transmits the control information at the time of an earthquake to the said at least one part node, when it determines with the said control part having an earthquake, The control information at the time of an earthquake is characterized by the above-mentioned. Gateway.
The receiving unit receives address information of the other gateway device from a management server that manages the gateway device and the other gateway device;
The gateway according to any one of claims 1 to 3, wherein the control unit stores the address information in a storage unit.
A gateway that manages multiple nodes in an area,
The vibration information related to the vibration detected in the at least some nodes is received from at least some of the plurality of nodes, and the earthquakes in other areas managed by the other gateway devices are received from the other gateway devices. A receiver for receiving earthquake information about occurrence of occurrence,
A controller that refers to the earthquake information in the other area and determines the presence or absence of an earthquake in the area;
A gateway, comprising: a transmission unit that transmits control information at the time of occurrence of an earthquake to the at least some of the nodes that transmitted the vibration information when an earthquake occurs in the area.
The gateway according to claim 5, wherein the control unit determines that an earthquake has occurred in the area when the earthquake information is information indicating that an earthquake has occurred in the other area.
The gateway according to claim 5, wherein the control unit performs statistical processing on the vibration information, and determines whether there is an earthquake in the area based on a result of the statistical processing and the earthquake information.
When the control unit is information indicating that an earthquake has occurred in the other area when the result of the statistical processing does not satisfy an earthquake determination condition, the control unit indicates that an earthquake has occurred in the area. The gateway according to claim 7, wherein the gateway is determined.
A gateway that manages multiple nodes in the area
Receiving vibration information relating to vibration detected in at least some of the nodes from at least some of the plurality of nodes;
Based on the vibration information, determine the presence or absence of an earthquake in the area,
The earthquake detection method characterized by performing the process which transmits the earthquake information containing the result of the said determination to another gateway apparatus.
A gateway that manages multiple nodes in the area
From other gateway devices, receive earthquake information regarding the occurrence of earthquakes in other areas managed by the other gateway devices,
Refer to the earthquake information in the other area, determine the presence or absence of an earthquake in the area,
An earthquake detection method, comprising: executing a process of transmitting control information when an earthquake occurs to at least some of the plurality of nodes when an earthquake occurs in the area.