# US 8,751,209 B2 · Simulation cache to expedite complex modeling and simulation processes > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 8,751,209 B2 - Document ID: US8751209B2 - Status: Granted - Kind: B2 - Application number: 11/686,170 - Filed: 2007-03-14 - Published: 2010-10-21 - Granted: 2014-06-10 - Earliest claimed: 2007-03-14 - Assignees: Exelis, Inc. - Applicants: Mark Daniel Henning; Michael J. Smith; Javad Sedehi; William Crocoll - Inventors: Mark Daniel Henning; Michael J. Smith; Javad Sedehi; William Crocoll - Web page: https://patentgrep.com/patent/US8751209B2 ## CPC - G06Q 10/04: Forecasting or optimisation specially adapted for administrative or management purposes, e.g. linear programming or "cutting stock problem" (market predictions or forecasting for commercial activities G06Q30/0202) - G01N 33/0075: {for multiple spatially distributed sensors, e.g. for environmental monitoring} - G06Q: INFORMATION AND COMMUNICATION TECHNOLOGY [ICT] SPECIALLY ADAPTED FOR ADMINISTRATIVE, COMMERCIAL, FINANCIAL, MANAGERIAL OR SUPERVISORY PURPOSES; SYSTEMS OR METHODS SPECIALLY ADAPTED FOR ADMINISTRATIVE, COMMERCIAL, FINANCIAL, MANAGERIAL OR SUPERVISORY PURPOSES, NOT OTHERWISE PROVIDED FOR - G01N: INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES (measuring or testing apparatus or processes other than immunoassay, involving enzymes or microorganisms C12M, C12Q) ## Abstract A method is provided for determining optimum positions in a region for a plurality of sensors that are capable of detecting occurrence of a hazard in the region. The hazard may be a chemical, biological, and/or radiological hazard in solid, liquid or gas form. A “simulation cache” is provided that stores data representing interaction of the hazard with sensors at each of the plurality of candidate locations in the region for each of the plurality of sensor types. Data is then retrieved from the simulation cache as needed for evaluation a particular candidate sensor solution comprising one or more sensors of one or more sensor types at corresponding ones of the candidate locations. An optimization algorithm may be used to select a candidate sensor solution. The data that is retrieved from the simulation cache for a selected candidate sensor solution is evaluated with respect to certain performance criteria. The simulation cache greatly reduces the time required to generate an optimum sensor layout because it separates the hazard modeling and sensor performance modeling from the optimization algorithm. By capturing this data at one time for storage in the simulation cache, it is not necessary to re-run the hazard simulations for each candidate sensor location generated by the optimization algorithm. ## Claims ### Claim 1 A method for determining optimum positions in a region for a plurality of sensors, wherein the sensors are capable of detecting occurrence of a hazard in the region, comprising: a. simulating occurrence and movement over time of the hazard in the region to produce data representative thereof; b. simulating a reaction of sensors at a set of all possible candidate sensor locations in the region and for each of a plurality of sensor types responsive to the simulated occurrence and movement of the hazard over time; c. storing in a simulation cache data resulting from the simulated reaction of the sensors at the set of all possible candidate sensor locations in the region for each of the plurality of sensor types responsive to the simulated occurrence and movement of the hazard over time; d. selecting one of a plurality of candidate sensor solutions, wherein each candidate sensor solution comprises one or more sensors of one or more sensor types at corresponding selected ones of the candidate sensor locations within the set of all possible candidate sensor locations; e. retrieving from the simulation cache data for the selected candidate sensor solution from the stored data; f. evaluating the data retrieved from the simulation cache from said (e) retrieving with respect to performance criteria for the selected one of the candidate sensor solutions; and g. selecting another one of the plurality of candidate sensor solutions and repeating (e) and (f), the another one of the plurality of candidate sensor solutions differing from the one of the plurality of candidate sensor solutions in at least one candidate sensor location or at least one sensor type. ### Claim 2 (depends on 1) The method of claim 1, and further comprising selecting one of the candidate sensor solutions based on said (f) evaluating. ### Claim 3 (depends on 1) The method of claim 1, wherein (d) selecting comprises selecting one of the plurality of candidate sensor solutions using an optimization algorithm that finds the sensor location(s) to optimize said performance criteria. ### Claim 4 (depends on 3) The method of claim 3, wherein (d) selecting comprises executing a genetic algorithm that searches for a candidate sensor solution among the plurality of candidate sensor solutions using biological evolution principles. ### Claim 5 (depends on 1) The method of claim 1, wherein (f) evaluating comprises assigning a score to the candidate sensor solution, and wherein (g) selecting comprises selecting another candidate sensor solution based on scores from (f) evaluating a plurality of other candidate sensor solutions. ### Claim 6 (depends on 1) The method of claim 1, wherein (f) evaluating comprises scoring data comprises for the selected candidate solution so that after a plurality of iterations of said (e) and (f) for a plurality of candidate sensor solutions, said (d) selecting finds the candidate sensor solution that provides an earliest average warning of the hazard to one or more assets or landmarks in or near the region. ### Claim 7 (depends on 1) The method of claim 1, wherein (d) selecting comprises selecting a candidate sensor solution that comprises a plurality of sensors of the same or different sensor type each at a corresponding one of the plurality of candidate sensor locations. ### Claim 8 (depends on 1) The method of claim 1, wherein said (a) simulating occurrence and movement over time, said (b) simulating reaction, and said (c) storing data resulting from the simulated reaction is performed for each of a plurality of hazards. ### Claim 9 (depends on 1) The method of claim 1, further comprising: selecting another one of the plurality of candidate sensor solutions and repeating said (e) retrieving; evaluating the data retrieved from the simulation cache with respect to performance criteria for the selected another one of the plurality of candidate sensor solutions; assigning a corresponding evaluation score to the selected another one of the plurality of candidate sensor solutions based on the evaluating the data retrieved from the simulation cache with respect to the performance criteria for the selected one of the candidate sensor solutions; and selecting an optimal one of the candidate sensor solutions based on the evaluation score assigned to the selected one of the plurality of candidate sensor solutions and the selected another one of the plurality of candidate sensor solutions. ### Claim 10 (depends on 9) The method of claim 9, wherein selecting another one of the candidate sensor solutions comprises the another one of the candidate sensor solutions based on the evaluation score assigned to the selected one of the candidate sensor solutions in said (g) assigning. ### Claim 11 A method for determining optimum positions in a region for a plurality of sensors, wherein the sensors are capable of detecting occurrence of a hazard in the region, comprising: a. simulating occurrence and movement over time of the hazard in the region to produce data representative thereof; b. simulating a reaction of sensors at a set of all possible candidate sensor locations in the region and for each of a plurality of sensor types responsive to the simulated occurrence and movement of the hazard over time; c. storing in a simulation cache alarm data resulting from the simulated reaction of the sensors at the set of all possible candidate sensor locations in the region for each of the plurality of sensor types responsive to the simulated occurrence and movement of the hazard over time, said alarm data indicating whether and when an alarm condition occurs at each of the plurality of candidate sensor locations for each of the plurality of sensor types; d. selecting one of a plurality of candidate sensor solutions using an optimization algorithm, wherein each candidate sensor solution comprises one or more sensors of one or more sensor types at corresponding selected ones of the candidate sensor locations within the set of all possible candidate sensor locations; e. retrieving from the simulation cache data for the selected candidate sensor solution from the stored data; and f. evaluating and scoring the retrieved data from said (e) retrieving with respect to performance criteria for the selected one of the candidate sensor solutions. ### Claim 12 (depends on 11) The method of claim 11, and further comprising: repeating said (d) selecting to select another one of the plurality of candidate sensors solutions based on said (f) evaluating so as to ultimately find an a candidate sensor solution that optimizes said performance criteria. ### Claim 13 (depends on 11) The method of claim 11, wherein (d) selecting comprises using an optimization algorithm that searches for a candidate sensor solution among the plurality of candidate sensor solutions using biological evolution principles. ### Claim 14 (depends on 11) The method of claim 11, wherein said (d) selecting comprises selecting the one of the plurality of candidate sensor solutions that comprises a plurality of sensors of the same or different sensor type each at a corresponding one of the plurality of candidate sensor locations. ### Claim 15 (depends on 11) The method of claim 11, further comprising selecting an optimal candidate sensor solution that provides an earliest warning of the hazard to one or more assets or landmarks in or near the region based on the assigned score assigned to each of the plurality of candidate sensor solutions after a plurality of iterations of said (g) evaluating and (h) assigning for each of the plurality of candidate sensor solutions. ### Claim 16 A non-transitory computer readable medium encoded with instructions that, when executed by a computer, cause the computer to generate output useful in determining optimum positions in a region for a plurality of sensors, wherein the sensors are capable of detecting occurrence of a hazard in the region, comprising: a. simulating occurrence and movement over time of the hazard in the region to produce data representative thereof; b. simulating a reaction of sensors at a set of all possible candidate sensor locations in the region and fore ach of a plurality of sensor types responsive to the simulated occurrence and movement over time; c. storing in a simulation cache data resulting from the simulated reaction of the sensors at the set of all possible candidate sensor locations in the region for each of the plurality of sensor types responsive to the simulated occurrence and movement of the hazard over time with the data representing the sensors at the set of all possible candidate sensor locations in the region for each of the plurality of sensor types; d. selecting one of a plurality of candidate sensor solutions, wherein each candidate sensor solution comprises one or more sensors of one or more sensor types at corresponding selected ones of the candidate sensor locations within the set of all possible candidate sensor locations; e. retrieving from the simulation cache data for the selected candidate sensor solution from the stored data; f. evaluating the data retrieved from the simulation cache from said (e) retrieving with respect to performance criteria for the selected one of the candidate sensor solutions; and g. selecting another one of the plurality of candidate sensor solutions and repeating (e) and (f), the another one of the plurality of candidate sensor solutions differing from the one of the plurality of candidate sensor solutions in at least one candidate sensor location or at least one sensor type. ### Claim 17 (depends on 16) The computer readable medium of claim 16, wherein said instructions for (c) storing data identified with the hazard comprise instructions for storing alarm data indicating whether and when an alarm condition occurs at each of the plurality of candidate sensor locations for each of the plurality of sensor types. ### Claim 18 (depends on 16) The computer readable medium of claim 16, wherein said instructions for (d) selecting comprises instructions for executing a genetic algorithm that searches for a candidate sensor solution among the plurality of candidate sensor solutions using biological evolution principles. ### Claim 19 (depends on 16) The computer readable medium of claim 16, wherein said instructions for (d) selecting comprises instructions for selecting the one of the plurality of candidate sensor solutions that comprises a plurality of sensors of the same or different sensor type each at a corresponding one of the plurality of candidate sensor locations. ### Claim 20 (depends on 16) The computer readable medium of claim 16, further comprising instructions comprising selecting an optimal candidate sensor solution that provides an earliest warning of the hazard to one or more assets or landmarks in or near the region based on the assigned score assigned to each of the plurality of candidate sensor solutions after a plurality of iterations of said (f) evaluating and (g) assigning for each of the plurality of candidate sensor solutions.