CN116757006A

CN116757006A - Layout optimization method and system for fire alarm based on digital twin city

Info

Publication number: CN116757006A
Application number: CN202311052211.5A
Authority: CN
Inventors: 曲龙泽; 吕宏武; 杨春薇
Original assignee: Suzhou Hege Information Technology Co ltd
Current assignee: Suzhou Hege Information Technology Co ltd
Priority date: 2023-08-21
Filing date: 2023-08-21
Publication date: 2023-09-15
Anticipated expiration: 2043-08-21
Also published as: CN116757006B

Abstract

The application provides a fire alarm layout optimization method and system based on a digital twin city, wherein the method comprises the following steps: constructing an urban 3D model based on a digital twin urban technology; setting basic attributes of the surfaces of the buildings; constructing square grids according to the set intervals, and projecting the grids to the whole urban ground surface and the building surface of the urban 3D model; the grid of the fire alarm can be deployed on the statistical model, and the central point coordinates of the grid are added to the deployment set; according to the set number N of preinstalled fire alarms, randomly selecting N grids in the deployment set as initial arrangement positions to generate an initial layout scheme of the fire alarms; different fire alarm layouts are obtained by adopting a variable neighborhood search algorithm with taboo and disturbance, and the fire alarm layout with the most inflammability grids is selected from the different fire alarm layouts to serve as an optimal scheme for deployment of the fire alarms. The application can provide maximum coverage with as little overhead as possible.

Description

Layout optimization method and system for fire alarm based on digital twin city

Technical Field

The invention relates to the field of fire safety, in particular to a layout optimization method and system of a fire alarm based on a digital twin city.

Background

In areas with dense urban population, building fires frequently occur, and life and property safety of personnel is seriously threatened. Because of the short spreading time and fast development speed of the fire, how to accurately monitor the fire in time and reduce the casualties and property loss caused by the fire is an important problem to be solved by urban managers, and thus a fire early warning system is generated. In the fire early warning system, the most basic part is a fire alarm. Because the fire alarm has limited covering capability and is easy to be shielded, the fire alarm is arranged in huge quantity in urban level even an astronomical number in order to completely cover without dead angles. However, the current layout of fire alarms is based entirely on designer experience, requiring extensive deployment in densely populated areas of the building, resulting in significant cost wastage.

Most of the existing fire early-warning methods carry out fire early-warning by judging the conditions of smoke, temperature and the like, and no related research on how to deploy and optimize the fire early-warning is provided.

Disclosure of Invention

The invention aims to provide a layout optimization method and system of a fire alarm based on a digital twin city, which are used for solving the problems that in the prior art, huge city building groups are faced, complete deployment is difficult to realize by completely depending on experience of designers, time and labor are wasted, and huge cost is caused.

In order to achieve the above purpose, the present invention adopts the following technical scheme:

on one hand, the invention discloses a fire alarm layout optimization method based on a digital twin city, which comprises the following steps:

s100, constructing an urban 3D model based on a digital twin urban technology; setting basic attributes of the surfaces of all buildings in the urban 3D model; the base attributes include: whether inflammable, whether a fire alarm can be deployed;

s200, constructing square grids according to the set intervals, and projecting the constructed grids to the whole urban ground surface and the building surface of the urban 3D model;

s300, counting grids capable of deploying fire alarms on the urban 3D model, and adding the coordinates of the central points of the grids to a deployment set;

s400, randomly selecting N grids from the deployment set of the urban 3D model as initial arrangement positions of the corresponding fire alarms according to the set number N of pre-installed fire alarms, and generating an initial layout scheme of the fire alarms;

S500, based on the initial layout scheme of the fire alarm, acquiring different fire alarm layouts by adopting a variable neighborhood search algorithm with taboo and disturbance, and selecting the fire alarm layout with the most inflammable grids as the optimal scheme for deployment of the fire alarm.

Preferably, the step S500 is based on the initial layout scheme of the fire alarm, and a variable neighborhood search algorithm with taboo and disturbance is adopted to obtain different fire alarm layouts, and the fire alarm layout with the most flammable grid coverage is selected from the different fire alarm layouts as the optimal scheme for deployment of the fire alarm; the method specifically comprises the following steps:

s510, acquiring the neighborhood of each fire alarm based on the initial layout scheme and the set neighborhood radius; selecting grids capable of deploying fire alarms from the neighborhood of each fire alarm to form a neighborhood set of the fire alarms;

s520, randomly selecting P grids from the neighborhood set of the fire alarm as temporary layout positions of the corresponding fire alarm; based on each temporary layout position of each fire alarm, combining to generate different temporary layout schemes of the fire alarms;

s530, eliminating temporary layout schemes listed in the tabu list, calculating inflammable coverage of all the temporary layout schemes of the fire alarms after the eliminating operation, and selecting the temporary layout scheme of the fire alarm with the highest inflammable coverage from the temporary layout schemes as a temporary optimal layout scheme; and the rest temporary layout schemes of the fire alarms are listed in a tabu list;

S540, judging whether the inflammable coverage of the temporary optimal layout scheme is larger than that of the initial layout scheme, if so, entering step S550; otherwise, step S560 is entered;

s550, the temporary optimal layout scheme is used as an initial layout scheme of the next iteration, and the current iteration times are reset to 0; returning to step S510;

s560, counting the current iteration times, and judging whether the current iteration times reach a neighborhood searching time threshold; if yes, go to step S570; otherwise, returning to step S520 to perform the next iteration;

s570, the current initial layout scheme is used as a preliminary optimal solution, a search neighborhood is enlarged through a variable neighborhood search algorithm with disturbance, and when the disturbance frequency reaches a set disturbance frequency threshold value, the fire alarm layout with the most inflammable grids is used as a final optimal solution of the fire alarm layout.

Preferably, in the step S570, the search neighborhood is enlarged by a variable neighborhood search algorithm with disturbance, and when the number of disturbance reaches a set disturbance number threshold, the fire alarm layout with the most flammable grid is used as the final optimal solution of the fire alarm layout; the method specifically comprises the following steps:

S571, expanding the neighborhood radius of each fire alarm in the current initial layout scheme to be an original designated multiple, and selecting grids capable of deploying the fire alarms from the original designated multiple to form a new neighborhood set corresponding to the fire alarms;

s572, randomly deleting the set proportion number of the grid numbers in the new neighborhood set of each fire alarm, sequentially selecting a specified number of grids which are not temporarily included in the neighborhood of any fire alarm from the deployment set, and adding the grids into the new neighborhood set of each fire alarm;

s573, initializing neighborhood search times to be 0, adding 1 to the disturbance times, returning to the step S520 until the disturbance times reach a preset disturbance times threshold value, and outputting the current layout of the fire alarm as the optimal layout.

Preferably, after the step S510, the step S520 further includes the step of:

s515, judging whether overlapping grids exist in the neighborhood set of each fire alarm, and if so, deleting the overlapping grids from the neighborhood set of each fire alarm.

Preferably, the formula for calculating the inflammable coverage of the temporary layout scheme of the fire alarm in the step S530 is as follows:

；

wherein ƒ (G) _j N) is the layout scheme G of the fire alarm _j Is a flammable coverage of (2); k is the number of all flammable grids in the whole digital twin city, N _red (G _j N) is the current fire alarm layout scheme G _j The number of flammable grids covered; n is the number of fire alarms in the layout;

the current fire alarm layout scheme G _j The number statistics step of the inflammability grid covered by each fire alarm comprises the following steps:

s531, based on the coverage radius of the fire alarm, acquiring inflammable grids in the coverage range of the fire alarm, and recording the center point set of the grids as A;

s532, based on the urban 3D model, executing a ray propagation algorithm, judging whether each inflammable grid in the set A is a direct view point of the current fire alarm or not, and marking all inflammable grids judged to be the direct view points;

s533, counting the marked inflammability grids to obtain the number of the current fire alarm covering inflammability grids.

Preferably, in the step S532, it is determined whether each grid in the set a is a direct view point of the current fire alarm; the method specifically comprises the following steps:

s5321, determining a limiting space of the grid to be judged based on the position coordinates of the grid to be judged in the set A and the set limiting radius;

S5322, acquiring all reference planes of the urban 3D model existing in the limited space; obtaining mirror image points of the center point of the grid to be judged and each reference plane; the plane corresponding to the center point and the mirror image point of the grid to be judged is regarded as a target reference plane;

s5323, traversing each reference plane for each image point, wherein whether reference planes intersected with a target connecting line exist or not except the target reference plane; if yes, judging that the grid to be judged is not a direct view point of the fire alarm; otherwise, judging that the grid to be judged is a direct view point of the fire alarm; the target connecting line is a connecting line of the mirror image point and the central point of the grid where the fire alarm is located.

s5324, acquiring a connecting line of a center point of a grid to be judged currently in the set A and a center point of a grid where the current fire alarm is located, and acquiring a rectangular detection space by taking the connecting line as a diagonal line;

s5325, dividing the cuboid detection space into M subspace areas; m is a positive integer greater than 1;

S5326, acquiring a subspace region intersected with the connecting line as a target subspace region;

s5327, judging whether grids exist in each target subspace area in sequence; if yes, traversing grids in the target subspace area, and judging whether the center point of the grids is positioned on the connecting line or not;

s5328, if the central point of each grid in all the target subspace areas is not located on the connecting line, judging that the grid to be judged currently is a direct-view point of the current fire alarm;

s5329, if grids with grid center points positioned on the connecting line exist in each target subspace area, judging that the grid to be judged currently is not the direct-view point of the current fire alarm.

Preferably, the method for laying out fire alarms based on digital twin cities further comprises the following steps:

s600, judging whether the inflammable coverage of the inflammable grid covered by the optimal scheme of the fire alarm deployment reaches the set inflammable coverage; if yes, the optimal scheme of the current fire alarm deployment is used as a final layout scheme; if not, go to step S710;

s710, detecting and acquiring flammable grids which are not covered by any fire alarm as target grids based on the optimal scheme of the current deployment of the fire alarm;

S720, clustering the target grids, and obtaining a region containing the class with the largest number of the target grids as a first target region;

s730, determining grids capable of deploying fire alarms in the first target area, and selecting grids with the largest coverage of the target grids from the grids as newly-added fire alarm deployment points;

s740, updating the optimal scheme of the fire alarm deployment, and returning to the step S600.

On the other hand, the invention also discloses a fire alarm layout system based on the digital twin city, which comprises the following steps: the system comprises a digital twin city module, an alarm layout module and a man-machine interaction module; wherein:

the digital twin city module specifically comprises:

the model construction submodule is used for constructing an urban 3D model based on a digital twin urban technology; setting basic attributes of the surfaces of all buildings in the urban 3D model; the base attributes include: whether inflammable, whether a fire alarm can be deployed;

the model gridding sub-module is used for constructing square grids according to the set interval and projecting the constructed grids to the whole urban surface and the building surface of the urban 3D model;

The alarm layout module specifically comprises:

the statistics sub-module is used for counting grids capable of deploying fire alarms on the urban 3D model and adding the central point coordinates of the grids to a deployment set;

the initialization submodule is used for randomly selecting N grids in the deployment set of the urban 3D model as initial arrangement positions of the corresponding fire alarms according to the set number N of the preinstalled fire alarms, and generating an initial layout scheme of the fire alarms;

the layout optimization sub-module is used for acquiring different fire alarm layouts by adopting a variable neighborhood search algorithm with taboo and disturbance based on an initial layout scheme of the fire alarm, and selecting the fire alarm layout with the most inflammability grids from the different fire alarm layouts as an optimal scheme for deployment of the fire alarm;

the man-machine interaction module is used for carrying out man-machine interaction with a user, and comprises a command for receiving the input of the user and displaying the optimal scheme of the fire alarm deployment generated by the alarm layout module to the user.

Preferably, the layout optimization submodule specifically includes:

the neighborhood set construction unit is used for acquiring the neighborhood of each fire alarm based on the initial layout scheme and the set neighborhood radius; selecting grids capable of deploying fire alarms from the neighborhood of each fire alarm to form a neighborhood set of the fire alarms;

The temporary layout generation unit is used for randomly selecting P grids from the neighborhood set of the fire alarm as temporary layout positions of the corresponding fire alarm; based on each temporary layout position of each fire alarm, combining to generate different temporary layout schemes of the fire alarms;

the tabu list construction unit is used for constructing a tabu list, and the tabu list is used for storing the layout scheme of the obsolete fire alarm;

the first optimizing unit is used for eliminating temporary layout schemes listed in the tabu list, calculating inflammable coverage of all the temporary layout schemes of the fire alarms after the eliminating operation, and selecting the temporary layout scheme of the fire alarm with the highest inflammable coverage from the inflammable coverage as a temporary optimal layout scheme; and the rest temporary layout schemes of the fire alarms are listed in a tabu list;

the judging operation unit is used for judging whether the inflammable coverage of the temporary optimal layout scheme is larger than that of the initial layout scheme, if yes, the temporary optimal layout scheme is used as the initial layout scheme of the next iteration, the current iteration times are reset to 0, the neighborhood set of each fire alarm in the new initial layout scheme is reconstructed through the neighborhood construction module, and the next iteration is continued;

The statistics unit is used for counting the current iteration times and judging whether the current iteration times reach a neighborhood searching time threshold value or not when the inflammable coverage of the temporary optimal layout scheme is smaller than that of the initial layout scheme; if not, re-selecting P grids through the temporary layout generating unit, and continuing the next iteration;

the neighborhood expansion subunit is used for expanding the neighborhood radius of each fire alarm in the current initial layout scheme to an original designated multiple when the current iteration number reaches the neighborhood search number threshold value, and selecting grids capable of deploying the fire alarms from the neighborhood radius to form a new neighborhood set corresponding to the fire alarms;

the element increasing and decreasing unit is used for randomly deleting the set proportion number of the grid number in the new neighborhood set of each fire alarm, and sequentially selecting a specified number of grids which are not included in the neighborhood of any fire alarm currently from the deployment set to add the grids into the new neighborhood set of each fire alarm;

and the comparison processing unit is used for initializing the neighborhood search frequency to be 0, adding 1 to the disturbance frequency, returning to the first optimization unit, continuing to perform optimization iteration until the disturbance frequency reaches a preset disturbance frequency threshold value, and outputting the current layout of the fire alarm as the optimal layout.

The invention has at least one of the following beneficial technical effects:

(1) The deployment optimization method of the fire alarm based on the digital twin city can provide the largest coverage range on the least expense as much as possible, so that the fire early warning of the city is more comprehensive, and the safety of urban residents is ensured.

(2) The invention adopts a variable neighborhood search algorithm with taboo and disturbance, and stores the obsolete layout scheme into the taboo list through the adoption of the taboo list, thereby the repeated obsolete scheme can be quickly compared and removed in the follow-up process, the repeated calculation of the repeated temporary scheme is avoided, and the calculation force is reduced. After the disturbance operation is added, the deployment scheme can be rapidly determined, and the local optimal solution is not easy to fall into. Preferably, in the invention, the neighborhood radius is not simply enlarged, but a certain proportion of grid numbers are randomly deleted after the neighborhood radius is enlarged, and then the grid numbers capable of being provided with fire alarms are randomly absorbed from the urban space of the 3D model to be brought into a new neighborhood set, so that the space limitation of local optimal solution is jumped out, and the superiority of the scheme is improved.

(3) In the invention, when the number of the inflammable grids of the fire alarm is calculated, the inflammable grids in the physical coverage area of the fire alarm are not simply included in statistics, but whether the inflammable grids in the physical coverage area of the physical distribution are direct view points of the fire alarm or not can be further judged, if the inflammable grids are not the direct view points, the fire alarm is likely to be difficult to monitor the blocked inflammable grids if the inflammable grids are blocked by the obstacles, and after the inflammable grids of the non-direct view points are removed, the number of the inflammable grids in the coverage area of the fire alarm is more accurate, so that the accuracy of layout optimization of the fire alarm is improved.

(4) The invention builds the city 3D model based on the digital twin city technology, thereby accurately presenting various data information of the city on the model, including whether the city surface and the building surface are inflammable, whether fire alarms can be deployed, and the like. On the basis of the constructed city model, projection processing is further carried out through equidistant grids, so that the whole city ground surface and the building surface are subjected to gridding positioning, the subsequent layout positioning of the fire alarm is greatly facilitated, and the layout scheme is simplified.

(5) According to the invention, after the optimal scheme of the current deployment of the fire alarm is obtained by adopting the variable neighborhood search algorithm with taboo and disturbance, the whole inflammable coverage of the scheme is further judged, and if the inflammable coverage does not meet the set requirement, the fire alarm is further added on the basis of the inflammable grid which is not covered, so that the coverage requirement is met. The scheme for adding the fire alarm is additionally arranged on the basis of the original optimal scheme, the position layout of the original alarm is not changed, the workload of data processing is greatly reduced, and the efficiency is improved.

The foregoing description is only an overview of the present invention, and is intended to provide a better understanding of the present invention, as it is embodied in the following description, with reference to the preferred embodiments of the present invention and the accompanying drawings. Specific embodiments of the present invention are given in detail by the following examples and the accompanying drawings.

Drawings

The accompanying drawings, which are included to provide a further understanding of the application and are incorporated in and constitute a part of this specification, illustrate embodiments of the application and together with the description serve to explain the application and do not constitute a limitation on the application. In the drawings:

FIG. 1 is a flow chart of one embodiment of a digital twinning city based fire alarm layout optimization method of the present application;

FIG. 2 is a flow chart of another embodiment of a digital twinning city based fire alarm layout optimization method of the present application;

FIG. 3 is a block diagram of one embodiment of a digital twinning city based fire alarm layout optimization system of the present application.

Detailed Description

The principles and features of the present application are described below with reference to the drawings, the examples are illustrated for the purpose of illustrating the application and are not to be construed as limiting the scope of the application. The application is more particularly described by way of example in the following paragraphs with reference to the drawings. Advantages and features of the application will become more apparent from the following description and from the claims. It should be noted that the drawings are in a very simplified form and are all to a non-precise scale, merely for convenience and clarity in aiding in the description of embodiments of the application.

Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. The terminology used herein in the description of the invention is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention.

The method for optimizing the layout of the fire alarm based on the digital twin city shown in fig. 1 comprises the following steps:

specifically, a 3D model of a city can be built by utilizing a digital twin technology, information and data of each dimension in the city are superimposed, such as whether the outer surface of a building is inflammable or not, whether a fire alarm and other information can be deployed, and simulation of various scenes in the city is realized.

Specifically, in order to better position the position coordinates of each part in the 3D model, the embodiment adopts a grid projection mode, firstly constructs square grids, then projects the square grids onto the urban ground surface of the whole 3D model, and realizes the full-gridding coverage of the 3D model city, so that any position on the urban ground surface or the building surface can be positioned and represented by the grid coordinates, and the subsequent alarm layout positioning is also facilitated. As for the side length setting of the grid, the setting can be performed in advance according to the specific situation, if the positioning is to be finer, the side length setting of the grid is shorter, of course, the shorter the side length is, the larger the subsequent data processing amount is, and therefore, the setting can be generally compromise according to the actual situation.

Generally, square grids are constructed on a horizontal plane XY plane at intervals of M meters, the centers of the grids are recorded as O, the constructed grids are projected to the whole urban ground surface, and the projection point of O is OXY. Then, square grids are constructed at intervals of M meters in the XZ and YZ directions, the centers of the grids are marked as O, the constructed grids are projected onto the surfaces of all buildings, and the projection points are marked as OXZ and OYZ.

Specifically, because the basic attribute of the outer surface of the building is set during the model construction, whether the fire alarm can be deployed or not is included, after gridding, grids capable of deploying the fire alarm can be counted and the coordinate positions of the grids can be positioned, and the grids capable of deploying the fire alarm are assembled to form a deployment set.

specifically, the number N of pre-installed fire alarms can be set in advance, the set value can be set according to the area or the size of the city model, further, the set value can be set according to the number of flammable grids in the 3D city model, the setting calculation mode of the number N of the fire alarms is not limited, and after the number of the fire alarms is set, the scheme of the application can realize wider coverage and reduce cost. In view of the number of alarms being N, N grids can be randomly selected from the deployment set of the 3D model to serve as initial arrangement positions of the fire alarms, so that an initial layout scheme is formed.

S500, based on the initial layout scheme of the fire alarm, different fire alarm layouts are obtained by adopting a variable neighborhood search algorithm with taboo and disturbance. And selecting the fire alarm layout with the most inflammable grids as the optimal scheme for deployment of the fire alarms.

Specifically, based on the initial layout scheme, a variable neighborhood search algorithm (Variable Neighborhood Search with Shaking procedure and Tabu table, VNSST) with taboo and disturbance is adopted to obtain different fire alarm layouts. The VNSST algorithm is an improved variable neighborhood search algorithm, and compared with the traditional variable neighborhood search algorithm, the improved scheme fuses a tabu list and disturbance processing, so that more fire alarm layout schemes are obtained, and the fire alarm layout with the most inflammability grids is selected as an optimal scheme.

According to the embodiment, a 3D model is constructed through a digital twin city technology, and the 3D model of the city is subjected to gridding treatment, so that the layout positioning of subsequent fire alarms is facilitated, finally, based on N grids which are randomly selected and can be deployed as initial layout positions, various different fire alarm layouts are obtained by adopting a variable neighborhood search algorithm with taboo and disturbance, and therefore, the scheme with the most flammable grids is selected as an optimal solution, the largest coverage range can be provided on the least cost as possible, the fire warning of the city is more comprehensive, and the urban resident safety is ensured.

In another embodiment of the present invention, based on the foregoing embodiment, the step S500 is to obtain different fire alarm layouts by using a variable neighborhood search algorithm with taboo and disturbance based on the initial layout scheme of the fire alarm, and select the fire alarm layout with the most flammable grids as the optimal scheme for deployment of the fire alarm; specifically, as shown in fig. 2, the method includes:

specifically, the coverage radius of the alarm and the neighborhood of the alarm can be set in advance, and the coverage radius of the alarm and the neighborhood of the alarm are not equal, the coverage radius of the alarm is used for measuring the physical range of the inflammable point which can be detected by the alarm, namely, the fire alarm is taken as the center, and objects which are far from the coverage radius range of the fire alarm are the fire monitoring range of the fire alarm. The neighborhood radius is a radius value set by the user, and in general, the neighborhood radius of the alarm can be set to be larger than the coverage radius of the alarm. The initial layout scheme is noted as the current layout. For each alarm position of the current layout, a neighborhood is defined, which is a spherical space with a radius Ra. Grid elements in the neighborhood of the fire alarm, where the fire alarm can be arranged, are placed in a set to form a neighborhood set of the fire alarm, so that each fire alarm has a corresponding neighborhood set.

More preferably, after the neighborhood set of each fire alarm is generated, whether the neighborhood set of each fire alarm has a coincident grid is further judged, and if so, the coincident grid is deleted from the neighborhood set of each fire alarm. Therefore, the temporary layout scheme with 2 or more fire alarms arranged on the same grid can be avoided, and the subsequent data processing capacity is reduced.

specifically, after P grids are randomly selected from the neighborhood set of fire alarms (P is an integer greater than 0), each grid can be used as a layout position of the fire alarm, that is, each alarm has P optional layout positions, then N alarms are used, so that a very large number of layout schemes can be generated, and the layout schemes are traversed subsequently to select a local optimal scheme from the layout schemes.

Specifically, in order to reduce the subsequent data processing amount, in this embodiment, a tabu list is adopted, all the obsolete layout schemes are listed in the tabu list, and then after a new scheme is obtained, comparison is also required in the tabu list, so as to avoid that the scheme is a previously obsolete scheme, and therefore the calculation force is wasted.

specifically, the temporary optimal layout scheme is compared with the initial layout scheme, so that the inflammable coverage of which scheme is higher, that is, the number of inflammable grids covered by the scheme is the greatest. The formula for calculating the inflammable coverage of the temporary layout scheme of the fire alarm is as follows:

；

wherein ƒ (G) _j N) is the layout scheme G of the fire alarm _j Is a flammable coverage of (2); k represents the number of all flammable grids in the whole digital twin city, N _red (G _j N) is the current fire alarm layout scheme G _j The number of flammable grids covered; n is the number of fire alarms in the layout.

In general, however, the current fire alarm arrangement G _j The number of the inflammable grids covered in the middle is the sum of the number of inflammable grids covered by each fire alarm, and the repeated inflammable grids are removed; wherein, the number statistics step of the inflammability net covered by each fire alarm includes:

Specifically, when counting the number of the flammable grids covered by each alarm, not simply taking all the flammable grids in the coverage area of the alarm into statistics, but further distinguishing whether the flammable grids are direct view points of the fire alarm is needed, because if the flammable grids are shielded, fire early warning of monitoring the grids is difficult to cover actually, therefore, in the embodiment, on the basis of acquiring the flammable grids in the coverage radius range of the fire alarm, whether the flammable grids are direct view points of the fire alarm is further judged, so that whether the flammable grids are really in the monitoring coverage area of the fire alarm is determined, and the counted number is more accurate and practical.

s560, counting the current iteration times, and judging whether the current iteration times reach the neighborhood searching times threshold; if yes, go to step S570; otherwise, returning to step S520 to perform the next iteration;

Specifically, if the number of flammable grids covered by the temporary optimal layout scheme is higher than that of the initial layout scheme, the temporary optimal layout scheme is used as the initial layout scheme of the next iteration, the current iteration number is reset to 0, the previous step S510 is returned, iteration is continued until the number of flammable grids of the temporary optimal partial scheme is not higher than that of the initial layout scheme, and the number of continuous iteration in the case reaches the set neighborhood searching number threshold. For example, if the threshold of the neighborhood search times is set to SS, if the inflammable coverage of the temporary optimal layout scheme appears for the continuous SS times to be smaller than or equal to the inflammable coverage of the initial layout scheme, the current iteration is ended, the disturbance program is executed, and after the neighborhood of the current initial layout scheme (i.e. the current optimal layout scheme) is expanded through the disturbance operation, the method returns to continue searching the optimal layout. Before the disturbance operation is executed, the local optimal scheme is found through a certain number of iterations, however, the local optimal scheme is likely to be limited to a certain space range, and has a certain limitation, so after the local optimal solution is obtained, the disturbance is further performed, the space range of a neighborhood is enlarged, more inflammable grid elements are absorbed, the previous steps are returned to continuously find the optimal layout scheme after the enlarged range, and the disturbance times are generally set to 2-3 times.

According to another method embodiment of the present application, on the basis of the above embodiment, the search neighborhood is enlarged by the variable neighborhood search algorithm with disturbance in the step S570, and when the disturbance frequency reaches the set disturbance frequency threshold, the fire alarm layout with the most flammable grid is used as the final optimal solution of the fire alarm layout; the embodiment is further refined, and specifically includes:

s572, randomly deleting the set proportion number of the grid numbers in the new neighborhood set of each fire alarm, sequentially selecting a specified number of grids which are not temporarily included in the neighborhood of any fire alarm from the deployment set, and adding the grids into the new neighborhood set of each fire alarm; wherein, the grids in the new neighborhood set added to each fire alarm are not overlapped;

Specifically, in this embodiment, for the disturbance scheme, the neighborhood of the fire alarm in the current layout scheme is not simply enlarged, but after the neighborhood is enlarged, the specified number of grid numbers in the neighborhood is randomly deleted, and other grid elements are added from the 3D city model, so that the local optimal solution is jumped out, and the superiority and rationality of the scheme are improved. Of course, the number of deletions and the number of additions may be equal or different, and are not limited in this embodiment.

In a single further embodiment of the present application, based on the second embodiment, in the step S532, it is determined whether each grid in the set a is a direct view point of the current fire alarm; the method specifically comprises the following steps:

the data volume of calculation processing can be greatly reduced by limiting the radius, and the limited space is constructed by taking the center point of the grid to be determined as the center of sphere and combining the spherical space obtained by the set limited radius as the limited space.

In particular, the reference plane present in the defined space, i.e. the surfaces of the objects in the defined space.

Specifically, for the flammable grid within the physical coverage area of the fire alarm, if the flammable grid is not a direct view point of the fire alarm, that is, if there is a shielding between the flammable grid and the fire alarm, even if the flammable grid is located within the physical coverage area of the fire alarm, the fire alarm cannot truly monitor the fire early warning condition of the flammable grid, so when the number of flammable grids covered by the fire alarm is calculated, the flammable grid with non-direct view points needs to be removed. In this embodiment, based on the principle of counter-propagation, the above scheme is adopted to determine whether the flammable grid to be determined in the physical coverage area is a direct view point of the fire alarm, so as to determine whether the flammable grid belongs to the real coverage area of the fire alarm.

Of course, it is determined whether the flammable grid within the physical coverage area of the fire alarm is a direct view point of the fire alarm, and other schemes may be used for determination. Specifically, judging whether each grid in the set A is a direct view point of the current fire alarm; the method can be realized by the following steps:

In the scheme, a space connecting line is firstly obtained based on the central point of the grid to be judged and the position point of the fire alarm which currently covers the grid to be judged, then a cuboid detection space is obtained by taking the connecting line as a diagonal line, so that the range can be greatly reduced, the data processing amount is reduced, and then the area intersected with the connecting line is selected to be further judged based on the fact that the cuboid detection space is divided into M equal subspace areas. After the space area is divided, the locking target area is further reduced, the space area which is not intersected with the connecting line is definitely not blocked, so that the intersecting subspace area is only needed to be calculated, finally, whether grids exist in the intersecting subspace area is judged, if no grids exist, the fact that no object exists (the surfaces of objects such as buildings are subjected to gridding treatment) is indicated, the blocking cannot be caused, if grids exist, whether the grids in the subspace area are located on the connecting line acquired in the front is further judged, if yes, the blocking is indicated, and the center point of the grid to be judged is not the direct view point of the current fire alarm. And if the central point of each grid in all the target subspace areas is not positioned on the connecting line, judging that the grid to be judged currently is the direct-view point of the current fire alarm.

In another embodiment of the method of the present application, based on any of the above embodiments, after obtaining the optimal deployment schemes of the N alarms, further determining whether the obtained flammable coverage of the optimal scheme reaches the set flammable coverage, if not, further adding fire alarms is required. Specifically, the method of this embodiment includes the following steps:

S500, based on the initial layout scheme of the fire alarm, acquiring different fire alarm layouts by adopting a variable neighborhood search algorithm with taboo and disturbance, and selecting the fire alarm layout with the most inflammability grids as an optimal scheme for deployment of the fire alarm;

Because the number N of pre-installed fire alarms that are initially set is generally initially set according to the urban area or urban volume rate, or the total number of flammable grids, and the urban environment is responsible, even if layout optimization is performed, so that the N alarms cover as many flammable grids as possible, there may be a situation that the flammable coverage rate of the optimized scheme does not reach the expected value, and for this situation, further optimization processing is performed, and the alarms are gradually increased until the set flammable coverage rate is reached based on the original scheme. According to the scheme, the optimal layout scheme obtained after the optimal layout is not damaged, so that the data processing capacity and complexity are greatly reduced, and the set inflammable coverage is achieved under the condition that the number of fire alarms is as small as possible.

In another embodiment of the method, after a city 3D model is constructed by adopting a twin digital city technology, the city 3D model is subjected to gridding treatment, each basic attribute of the city 3D model is set, and then the layout optimization of the fire alarm is performed based on the gridded 3D model, wherein the specific flow is as follows:

(1) Initializing. The number N of alarms, the position of each alarm, the maximum coverage radius of each alarm, the calculation grid spacing and the fire early warning deployment optimization method parameter set based on the digital twin city are preset by a system administrator.

(1.1) the setting method for calculating the grid spacing specifically comprises the following steps: and constructing square grids on a horizontal plane XY plane at intervals of M meters, recording the centers of the grids as O, and projecting the constructed grids to the whole urban ground surface, wherein the projection point of O is OXY. Then, square grids are constructed at intervals of M meters in the XZ and YZ directions, the centers of the grids are marked as O, the constructed grids are projected onto the surfaces of all buildings, and the projection points are marked as OXZ and OYZ.

And (1.2) counting the attributes of planes of all grid center points, if the attributes are inflammable, adding 1 until all planes are traversed to obtain a result K, and marking the K grids with stripes.

And (1.3) judging whether the center of each grid allows the cloud deck scanning type fire alarm to be deployed, and if so, adding the center point coordinate information to the set Z.

(2) Optimization is performed. And executing a visible region judgment preprocessing method and a fire early warning deployment optimization method based on a digital twin city to generate a deployment scheme, wherein the deployment scheme consists of the labels and three-dimensional coordinates of all alarms.

(2.1) a visible region judgment preprocessing method; the method specifically comprises the following substeps:

(2.1.1) regarding any pan-tilt scanning type fire early warning alarm i, setting the coverage radius of the pan-tilt scanning type fire early warning alarm i as li, judging grids completely falling in the coverage range, and recording the center point set of the grids as A.

(2.1.2) for each element AE in a, judging whether the face of the grid is flammable or not according to the digital twin city module information, if so, marking the flammable as red; incorporating all inflammability grids in A into a set C;

(2.1.3) for each grid element CE in the C and the alarm i, executing a ray propagation algorithm according to the digital twin city module information, judging whether the CE is a direct view point of the alarm i, and if so, marking the grid where the CE is positioned as yellow. This step is performed until each CE is traversed.

(2.2) executing a fire alarm layout optimization method based on a digital twin city; the method specifically comprises the following substeps:

(2.2.1) numbering the positions of the deployable alarms according to set Z in increasing order from 1.

(2.2.2) according to the number N of alarms preset by a system administrator and the position of each alarm, arranging the alarms selected by initialization on the positions of the deployable alarms in the digital twin city according to the serial number sequence to form an initial layout scheme G ₀ 。

(2.2.3) generating an optimal alarm layout result by adopting an alarm layout method based on a variable neighborhood search algorithm (Variable Neighborhood Search with Shaking procedure and Tabu table, VNSST) of band tabu and disturbance.

The method for arranging the alarm based on the VNSST in the step (2.2.3) comprises the following steps:

(2.2.3.1) initial layout scheme G ₀ The current layout is noted. For each alarm position of the current layout, a neighborhood is defined, which is a sphere with a radius Ra. Put a selectable position in the neighborhood of alarm j to set H _j Is a kind of medium. Initializing the neighborhood search times counter=0, the disturbance times counter counter=0, and the tabu list TL is empty. And initializing a maximum neighborhood search frequency threshold SH and a maximum disturbance frequency threshold SS.

(2.2.3.2) for N alarms, determine the set H of each alarm j _j If there are coincident elements, then delete from each set at the same time. From the neighborhood set H of each alarm j _j The invention refers to a temporary layout scheme, each temporary layout scheme comprises N optional positions.

(2.2.3.3) judging the New temporary layout plan G _j Whether belonging to the tabu list, if belonging to TL, skipping the scheme; otherwise, calculate each new temporary layout G _j Coverage evaluation index f (G) _j ) One of these temporary layout schemes selected to maximize coverage is denoted as G _best Other temporary schemes add to the tabu list TL. Wherein the method comprises the steps of， N _red (G _j N) is the current fire alarm layout scheme G _j The number of flammable grids (red grids) covered; k is the number of all inflammable grids (red grids) in the city 3D model, and the variable alarm layout G _j And the number N of alarms.

(2.2.3.4) if f (G) _best ）<=f(G ₀ ) And the counter h is less than the threshold SH, go to step (2.2.3.2); if f (G) _best ）<=f(G ₀ ) But counter H>-SH, then perform perturbation process (Shaking procedure), go to step (2.2.3.5); otherwise f (G) _best ）>f(G ₀ ) Alarm layout G ₀ Updated to G _best The counter h is reset to 0 and step 2.2.3.2 is re-executed.

(2.2.3.5) determining that if the counter is less than the threshold SS, expanding the neighborhood radius of each alarm of the current layout by 2 times, and placing the selected position in the neighborhood of alarm j into the set H _j In (a) and (b); for H _j The medium element performs two operations, H _j The middle element is deleted by half randomly, and |H is added randomly from the whole position space _j I/2 elements; initializing the neighborhood search count counter=0, incrementing the disturbance count counter by 1, and proceeding to step (2.2.3.2). If the counter reaches the threshold SS, outputting the current optimal scheme G _best 。

In the embodiment, a digital twin city is constructed, and in the virtual city, an improved variable neighborhood search algorithm (a variable neighborhood search algorithm with taboo and search) is utilized to perform fire early warning deployment optimization, so that fewer alarms are deployed while the early warning coverage area is ensured; or in the case of a certain number of fire alarms, the range covering the inflammable attribute surface is wider through layout optimization, so that the cost is reduced.

Based on the same technical conception, the invention also discloses a fire alarm layout system based on the digital twin city, which can adopt any one of the method embodiments to carry out the layout design of the fire alarm, in particular, as shown in fig. 3, the fire alarm layout system based on the digital twin city of the embodiment comprises: a digital twin city module 100, an alarm layout module 200, and a human-computer interaction module 300; wherein:

The digital twin city module 100 specifically includes:

a model construction sub-module 110 for constructing an urban 3D model based on digital twin city technology; setting basic attributes of the surfaces of all buildings in the urban 3D model; the base attributes include: whether inflammable, whether a fire alarm can be deployed;

the model gridding sub-module 120 is configured to construct square grids according to a set interval, and project the constructed grids onto the whole city surface and the building surface of the city 3D model;

the alarm layout module 200 specifically includes:

a statistics sub-module 210, configured to count grids on the urban 3D model that can deploy fire alarms, and add coordinates of a center point thereof to a deployment set;

an initialization submodule 220, configured to randomly select N grids in the deployment set of the urban 3D model as initial placement positions of corresponding fire alarms according to the set number N of pre-installed fire alarms, and generate an initial placement scheme of the fire alarms;

the layout optimization sub-module 230 is configured to obtain different fire alarm layouts by adopting a variable neighborhood search algorithm with taboo and disturbance based on an initial layout scheme of the fire alarm, and select a fire alarm layout with the most inflammability grid coverage from the different fire alarm layouts as an optimal scheme for deployment of the fire alarm;

The man-machine interaction module 300 is configured to perform man-machine interaction with a user, and includes receiving an instruction input by the user, and displaying an optimal scheme of fire alarm deployment generated by the alarm layout module 200 to the user.

Specifically, in the system of the embodiment, the digital twin city module is connected with the alarm layout module, and the alarm layout module is connected with the man-machine interaction module. The digital twin city module transmits city virtual data information to the alarm layout module; the alarm layout module gives the optimal deployment position of the fire alarm; and transmitting the deployment result to a man-machine interaction module, wherein the man-machine interaction module is responsible for completing man-machine interaction with the city manager.

The digital twin city module is responsible for 3D model construction of the entire city, each building has a series of faces, and each three intersecting faces define a vertex. The properties of the building's face, including whether it is flammable, whether fire alarms can be deployed, etc. After the model is constructed, square grids are constructed according to the set grid spacing M, and the grids are projected to the surface of the urban 3D model, so that the urban ground surface is covered and divided by the grids, and any position of the urban ground surface or the building surface can be positioned and represented through the center coordinates of the corresponding grids. After gridding, the grids capable of deploying the fire alarm can be uniformly incorporated into a deployment set based on the previously set basic attributes of the building surface. The initial layout of the fire alarm can randomly select N grids from the deployment set as the initial layout positions of the fire alarm, so that an initial layout scheme of the fire alarm is formed. Of course, the initial layout scheme may be selected in other setting manners, which are not described herein.

The digital twin city module can also set basic information of each cradle head scanning type fire early warning alarm according to the input of the man-machine interaction module, wherein the basic information comprises the maximum coverage range of the fire alarm, and the digital twin city module also comprises three-dimensional coordinates (X, Y, Z) of the fire alarm after the layout of the fire alarm is set.

The alarm layout module obtains different fire alarm layouts based on the initial arrangement position of each fire alarm by adopting a variable neighborhood search algorithm with taboo and disturbance, and selects the fire alarm layout with the most inflammability grids as an optimal scheme of the fire alarm layout, wherein the layout scheme consists of the labels and three-dimensional coordinates of all the alarms.

In another system embodiment of the present application, based on the system embodiment, the layout optimization submodule specifically includes:

the statistics unit is used for counting the current iteration times and judging whether the current iteration times reach the neighborhood searching times threshold value or not when the inflammable coverage of the temporary optimal layout scheme is smaller than that of the initial layout scheme; if not, re-selecting P grids through the temporary layout generating unit, and continuing the next iteration;

And the disturbance optimizing unit is used for taking the current initial layout scheme as a preliminary optimal solution when the current iteration number reaches the neighborhood searching number threshold value, expanding the searching neighborhood by using a variable neighborhood searching algorithm with disturbance, and taking the fire alarm layout with the most flammable grids as a final optimal solution of the fire alarm layout when the disturbance number reaches the set disturbance number threshold value.

Preferably, the disturbance optimizing unit specifically includes:

the neighborhood expansion subunit is used for expanding the neighborhood radius of each fire alarm in the current initial layout scheme to be an original designated multiple, and selecting grids capable of deploying the fire alarms from the original designated multiple to form a new neighborhood set corresponding to the fire alarms;

an element increasing and decreasing subunit, configured to randomly delete a set proportion number from the grid number in the new neighborhood set of each fire alarm, and sequentially select a specified number of grids temporarily not included in the neighborhood of any fire alarm from the deployment set, and add the grids to the new neighborhood set of each fire alarm;

and the comparison processing subunit is used for initializing the neighborhood search frequency to be 0, adding 1 to the disturbance frequency, returning to the first optimization unit, continuing to perform optimization iteration until the disturbance frequency reaches a preset disturbance frequency threshold value, and outputting the current layout of the fire alarm as the optimal layout.

The detailed development in this embodiment illustrates how a variable neighborhood search algorithm with band contraindications and perturbations may be used to determine the optimal fire alarm layout. Specifically, a neighborhood set of each fire alarm is obtained based on an initial layout scheme, then inflammable coverage judgment is carried out one by one based on P grids selected in the neighborhood set, a temporary optimal layout is found out, then the temporary optimal layout is compared with the initial layout scheme, and a layout with large inflammable coverage is selected as the initial layout scheme of the next iteration. And after continuous iteration, stopping the current variable neighborhood search after a first iteration stopping condition is reached, wherein the first iteration stopping condition is that the duration of the inflammable coverage of the temporary optimal layout is smaller than that of the initial layout, and the preset variable neighborhood search frequency threshold is reached. In order to reduce the calculation amount, the application also adopts a tabu list, and the obsolete layout schemes are listed in the tabu list, thereby avoiding repeated scheme calculation and reducing the calculation force. And after the first iteration stop condition is reached, executing a disturbance program, expanding the neighborhood of the current fire alarm, returning to the variable neighborhood search algorithm to continuously acquire the optimal layout scheme, repeating the iteration until the disturbance times reach a set disturbance times threshold value, and obtaining the current layout scheme as the optimal layout scheme.

The technical details of the method embodiment of the present application are also applicable to the system embodiment, for example, when the coverage number of the flammable grid of the fire alarm is counted in the method embodiment, it is also required to first determine whether the flammable grid in the physical coverage area is a direct view point of the fire alarm, and the determination of the direct view point can be implemented by referring to the foregoing method, so that repetition is reduced and no further description is provided herein.

While the preferred embodiments of the present application have been described in detail, it will be appreciated that those skilled in the art, upon reading the above teachings, may make various changes and modifications to the application. Such equivalents are also intended to fall within the scope of the application as defined by the following claims.

Claims

1. A fire alarm layout optimization method based on a digital twin city is characterized by comprising the following steps:

2. The method for optimizing the layout of fire alarms based on the digital twin city according to claim 1, wherein the step S500 is based on the initial layout scheme of the fire alarms, adopts a variable neighborhood search algorithm with taboo and disturbance to obtain different fire alarm layouts, and selects the fire alarm layout with the most inflammability grids as the optimal scheme for deployment of the fire alarms; the method specifically comprises the following steps:

3. The method for optimizing the layout of fire alarms based on digital twin cities according to claim 2, wherein the step S570 is to expand the search neighborhood by a variable neighborhood search algorithm with disturbance, and to use the fire alarm layout with the most flammable grid as the final optimal solution of the fire alarm layout when the disturbance number reaches the set disturbance number threshold; the method specifically comprises the following steps:

4. The method for optimizing a fire alarm layout based on a digital twin city according to claim 2, wherein after the step S510, the step S520 is preceded by the further steps of:

5. The fire alarm layout optimization method based on digital twin cities according to claim 2, wherein the formula for calculating the inflammable coverage of the temporary layout scheme of the fire alarm in step S530 is as follows:

；

wherein ƒ (G) _j N) is the layout scheme G of the fire alarm _j Is a flammable coverage of (2); k is the number of all flammable grids in the city 3D model, N _red (G _j N) is the current fire alarm layout scheme G _j The number of flammable grids covered; n is the number of fire alarms in the layout;

s532, based on the urban 3D model, judging whether each inflammable grid in the set A is a direct view point of the current fire alarm or not, and marking all inflammable grids judged to be the direct view points;

6. The method for optimizing the layout of fire alarms based on digital twin cities according to claim 5, wherein in the step S532, it is judged whether each grid in the set a is a direct view point of the current fire alarm; the method specifically comprises the following steps:

s5322, acquiring all reference surfaces of the urban 3D model in the limited space; acquiring the central point of the grid to be determined and the mirror image points of each reference surface; the plane corresponding to the center point and the mirror image point of the grid to be judged is regarded as a target reference plane;

7. The method for optimizing the layout of fire alarms based on digital twin cities according to claim 5, wherein in the step S532, it is judged whether each grid in the set a is a direct view point of the current fire alarm; the method specifically comprises the following steps:

8. The digital twinning city-based fire alarm layout optimization method of any one of claims 1-7, further comprising the steps of:

9. A digital twinning city based fire alarm layout system, comprising: the system comprises a digital twin city module, an alarm layout module and a man-machine interaction module; wherein:

the digital twin city module specifically comprises:

the alarm layout module specifically comprises:

10. The digital twinning city-based fire alarm layout system of claim 9, wherein the layout optimization submodule specifically comprises:

the neighborhood expansion unit is used for expanding the neighborhood radius of each fire alarm in the current initial layout scheme to the original appointed multiple when the current iteration number reaches a neighborhood search number threshold value, and selecting grids capable of deploying the fire alarms from the preset multiples to form a new neighborhood set corresponding to the fire alarms;