# US 11,860,604 B2 · Analysis assistance apparatus, analysis assistance method, and computer-readable recording medium > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 11,860,604 B2 - Document ID: US11860604B2 - Status: Granted - Kind: B2 - Application number: 17/261,410 - Filed: 2018-07-26 - Published: 2021-08-26 - Granted: 2024-01-02 - Earliest claimed: 2018-07-26 - Assignees: NEC Corporation - Applicants: NEC Corporation - Inventors: Masafumi Watanabe - Web page: https://patentgrep.com/patent/US11860604B2 ## CPC - G05B 19/406: characterised by monitoring or safety (G05B19/19 takes precedence) - G05B 19/048: Monitoring; Safety - G05B 23/0216: {Human interface functionality, e.g. monitoring system providing help to the user in the selection of tests or in its configuration} - G06F 11/07: Responding to the occurrence of a fault, e.g. fault tolerance - G06F 11/36: Prevention of errors by analysis, debugging or testing of software - G05B 2219/34461: Inhibit access to area if dangerous, cover taken off - G05B 2219/50193: Safety in general - G05B: CONTROL OR REGULATING SYSTEMS IN GENERAL; FUNCTIONAL ELEMENTS OF SUCH SYSTEMS; MONITORING OR TESTING ARRANGEMENTS FOR SUCH SYSTEMS OR ELEMENTS (systems for controlling or regulating non-electric variables G05D; systems for regulating electric or magnetic variables G05F; control devices or systems insofar as characterised by mechanical features only G05G) - G06F: ELECTRIC DIGITAL DATA PROCESSING (computer systems based on specific computational models G06N) ## Abstract An analysis assistance apparatus 10 includes: a control program obtainment unit 11 that obtains a control program of a plant based on sensor data from a sensor installed in the plant; an event information obtainment unit 12 that obtains event information, which includes a variable that defines a state of the plant when a predetermined event has occurred and a value thereof, as information necessary for searching the control program for a safety barrier for avoiding the occurrence of the predetermined event in the plant; and a safety barrier search unit 13 that extracts, from the control program, a causal relationship between an input variable and an output variable, and searches the control program for the safety barrier based on the variable and the value included in the event information and on the extracted causal relationship. ## Claims ### Claim 1 An analysis assistance apparatus comprising: a processor; and a memory storing instructions executable by the processor to: obtain a control program for controlling respective parts of a plant based on sensor data from a sensor installed in the plant; obtain event information as information necessary for searching the control program for a safety barrier for avoiding an occurrence of a predetermined event in the plant, the event information including a variable that defines a state of the plant when the predetermined event has occurred and a value thereof; extract, from the obtained control program, a causal relationship between an input variable and an output variable in the control program; generate, with use of the variable and the value included in the event information and the extracted causal relationship, a state transition graph which indicates a state transition from the state defined by the variable and the value included in the event information, and which includes an origin point and an end point of the transition and a transition condition that causes the transition; and search the control program for the safety barrier based on the variable and the value included in the obtained event information and on the extracted causal relationship, by specifying, from the generated state transition graph, a transition to a state where the occurrence of the predetermined event has been avoided. ### Claim 2 (depends on 1) The analysis assistance apparatus according to claim 1, wherein the instructions are executable by the processor to further: derive a new event in which the safety barrier that has been searched for has a possibility of not functioning; and display the specified safety barrier and the derived new event on a screen. ### Claim 3 (depends on 1) The analysis assistance apparatus according to claim 1, wherein in a case where the plant includes a plurality of control devices that execute the control program and a network via which the plurality of control devices are interconnected, the control program is obtained for each of the control devices, and the safety barrier is searched for from the control program executed by each of the control devices. ### Claim 4 An analysis assistance method comprising: obtaining, by a processor, a control program for controlling respective parts of a plant based on sensor data from a sensor installed in the plant; obtaining, by the processor, event information as information necessary for searching the control program for a safety barrier for avoiding an occurrence of a predetermined event in the plant, the event information including a variable that defines a state of the plant when the predetermined event has occurred and a value thereof; extracting, by the processor and from the obtained control program, a causal relationship between an input variable and an output variable in the control program; generating, by the processor and with use of the variable and the value included in the event information and the extracted causal relationship, a state transition graph which indicates a state transition from the state defined by the variable and the value included in the event information, and which includes an origin point and an end point of the transition and a transition condition that causes the transition; and searching, by the processor, the control program for the safety barrier based on the variable and the value included in the obtained event information and on the extracted causal relationship, by specifying, from the generated state transition graph, a transition to a state where the occurrence of the predetermined event has been avoided. ### Claim 5 (depends on 4) The analysis assistance method according to claim 4, further comprising: deriving, by the processor, a new event in which the safety barrier that has been searched for has a possibility of not functioning; and displaying, by the processor, the specified safety barrier and the derived new event on a screen. ### Claim 6 (depends on 5) The analysis assistance method according to claim 5, wherein in a case where the plant includes a plurality of control devices that execute the control program and a network via which the plurality of control devices are interconnected, the control program is obtained for each of the control devices, and the safety barrier is searched for from the control program executed by each of the control devices. ### Claim 7 A non-transitory computer-readable recording medium storing a program executable by a computer to carry out: obtaining a control program for controlling respective parts of a plant based on sensor data from a sensor installed in the plant; obtaining event information as information necessary for searching the control program for a safety barrier for avoiding an occurrence of a predetermined event in the plant, the event information including a variable that defines a state of the plant when the predetermined event has occurred and a value thereof; extracting, by the processor and from the obtained control program, a causal relationship between an input variable and an output variable in the control program; generating, with use of the variable and the value included in the event information and the extracted causal relationship, a state transition graph which indicates a state transition from the state defined by the variable and the value included in the event information, and which includes an origin point and an end point of the transition and a transition condition that causes the transition; and searching the control program for the safety barrier based on the variable and the value included in the obtained event information and on the extracted causal relationship, by specifying, from the generated state transition graph, a transition to a state where the occurrence of the predetermined event has been avoided. ### Claim 8 (depends on 7) The non-transitory computer-readable recording medium according to claim 7, wherein the program is executable by the computer to further carry out: deriving a new event in which the safety barrier that has been searched for has a possibility of not functioning; and displaying the specified safety barrier and the derived new event on a screen. ### Claim 9 (depends on 7) The non-transitory computer-readable recording medium according to claim 7, wherein in a case where the plant includes a plurality of control devices that execute the control program and a network via which the plurality of control devices are interconnected, the control program is obtained for each of the control devices, and the safety barrier is searched for from the control program executed by each of the control devices.