Building space evacuation performance evaluation method based on weight network

Abstract

The invention discloses a building space evacuation performance evaluation method based on a weight network, and belongs to the technical field of building safety and emergency management. According to the method, the balance and stability of an evacuation path are comprehensively evaluated by abstracting a building space into a weight network and combining evacuation simulation and network analysis technologies. The method specifically comprises the following steps: constructing a topological network model of a building space, defining a weight coefficient of a node, dividing an exit service sub-graph, calculating an exit load index, a balance index and a node sensitivity index, and analyzing the stability of the network through node attack. The method solves the problems that in the prior art, multiple evacuation simulation is relied on, the process is tedious, and spatial structure performance cannot be visually reflected, key nodes can be rapidly recognized, evacuation path design is optimized, and evaluation efficiency and accuracy are remarkably improved. The method is suitable for evacuation design and performance evaluation of various crowded places such as teaching, exhibition, business, transportation hubs and the like.

Description

Technical Field

[0001] The present invention relates to the technical field of building safety and evacuation, and in particular to a building space evacuation performance evaluation method based on a weighted network. Background Art

[0002] Safe building evacuation is a core issue in ensuring the safety of people. The basic evacuation capabilities exhibited by certain spatial characteristics are related to spatial organization, functional layout characteristics, and occupant distribution, and are the basis for determining evacuation efficiency in specific scenarios.

[0003] The evacuation performance of a space primarily encompasses two aspects: evacuation balance and safety and stability. Evacuation balance refers to the fact that, except in rare cases, safe evacuation of public buildings is a multi-exit process. The structural organization of spatial paths influences the overall distribution of walkways, stairways, and emergency exits, preliminarily determining evacuation path selection and thus being a key factor influencing evacuation performance. Safety and stability refers to the ability of a building space to provide redundant evacuation paths and ensure the safe completion of the evacuation process in the event of structural damage due to disasters, congestion, or other factors.

[0004] The evacuation performance of a building directly impacts the safe evacuation process and efficiency. Evacuation efficiency refers to the ability of personnel to complete a safe evacuation process under specific environmental conditions. In a narrower sense, evacuation efficiency can be understood as evacuation time. Academic evaluations of evacuation efficiency often use evacuation time as a basis for determining safe evacuation efficiency. A safe evacuation process is established when the required safe evacuation time is met.

[0005] In existing technologies, evacuation efficiency assessment mainly relies on evacuation simulation software to calculate evacuation time in specific scenarios. However, this method has the following limitations:

[0006] 1. Modeling is difficult: Existing evacuation simulation software, such as the cellular automaton model BuildingEXODUS and the social force models Mass Motion and Pathfinder, require mastering multiple modeling software and performing relatively complex parameter settings. All of these softwares have certain modeling difficulties and are difficult to learn. In addition, commercial software is expensive, which to a certain extent limits the development of evacuation safety assessment, evacuation management and other businesses.

[0007] 2. The evaluation process is cumbersome: Evacuation simulation focuses on calculating the evacuation time value in specific scenarios and finding congestion bottleneck areas. For evacuation performance issues caused by differences in building space characteristics, it is necessary to adopt steps such as "scenario classification - multiple modeling - obtaining time - estimating performance". The process is relatively cumbersome, the results are not intuitive, time-consuming and difficult to intuitively reflect the spatial structure characteristics.

[0008] 3. Single evaluation indicator: Evacuation time is often used as the basis for judgment. However, evacuation time is a comprehensive numerical result affected by multiple factors such as personnel, space, and disasters. It is difficult to intuitively reflect the evacuation performance of the space based solely on the evacuation time value, and it is impossible to comprehensively evaluate the balance and stability of the evacuation path. For example, the ability of the building space to cope with path damage when the evacuation path is damaged is not considered, as well as the impact of damage at different locations on the overall evacuation performance.

[0009] Complex networks transform the elements of a real system and the relationships between them into network nodes and edges, emphasizing the topological properties and essential characteristics of the system structure. From a topological perspective, buildings can be viewed as network systems composed of spatial nodes and their connections. Nodes and edges are used to describe network systems with complex connectivity patterns and structural characteristics. The main idea is to transform the elements of a real system and the relationships between them into network nodes and edges, describing the relationships between the various parts of the real system in the form of a network. Nodes represent the various components of the system, and edges between nodes represent the connections between the components. This emphasizes the topological properties of the system structure and reveals the essential characteristics of the real system.

[0010] In the engineering field, complex networks are often used to study the topological characteristics, important nodes, and stability analysis of macro-scale networks such as urban road networks, urban bus networks, and rail transit networks.

[0011] In recent years, complex network theory has been introduced into architectural space research. From a topological perspective, a building is a network system composed of spaces and their connections. Nodes represent spatial elements, while edges represent the connections between spaces. By describing nodes and edges, the overall topological structure of a space can be expressed, exhibiting the basic characteristics of a complex network. For example, space syntax theory analyzes spatial structure using metrics such as topological depth and integration, but it still analyzes spatial relationships based on topological networks and does not integrate dynamic factors such as evacuation characteristics, population density, and area size with network analysis. The EVACNET model abstracts evacuation paths as a network, dividing space into nodes and edges. People move between nodes in a fluid manner, but it still primarily calculates evacuation time data.

[0012] Therefore, there is an urgent need for a network analysis method that comprehensively considers the evacuation characteristics of building space, integrates the weighted influences of space area, personnel density, etc., and analyzes the overall evacuation balance and stability of the space. Summary of the Invention

[0013] The technical problem to be solved by the present invention is to overcome the defects of the prior art and provide a building space evacuation performance evaluation method based on a weighted network.

[0014] In order to solve the above technical problems, the present invention provides the following technical solutions:

[0015] The present invention provides a building space evacuation performance evaluation method based on a weighted network, comprising the following steps:

[0016] Step 1: Processing architectural space information:

[0017] Select a typical building plan and simplify it, clarify the area, function, occupancy density, and location of evacuation exits of each space, and determine the spatial connections, including but not limited to corridor connections, door connections, and hall connections;

[0018] Step 2: Construct a topological network model of the building space:

[0019] According to the basic principles of architectural space-topological network translation, the architectural space is divided into nodes and edges. Nodes represent rooms, corridors, stairs, and emergency exit space units, while edges represent direct connectivity between spaces. Draw a topological network diagram.

[0020] Identify the name types of exits, rooms, and path nodes, and use Gephi 0.9.5 to draw the topological network diagram;

[0021] Step 3. Calculate node weights and draw a weighted network diagram:

[0022] Calculate all node weights in turn, node weight w i The calculation formula is: i =α i ×β i , where α i is the area scale normalized value of node i, β i is the normalized value of the personnel density of node i. The area and personnel density data of spatial nodes are processed using the maximum-minimum normalization method;

[0023] Based on the topological network diagram drawn in step 2, draw the evacuation weight network diagram and output the weight network diagram in the .graphml format;

[0024] Step 4: Divide each export service subgraph:

[0025] Input the weighted network graph drawn in step 3 and identify the shortest path between any non-exit node and all exit nodes;

[0026] Calculate the length of each shortest path, compare and select the shortest path, and include the node in the subgraph set served by the exit. If the number of shortest paths is greater than 1, the node weight is evenly distributed and included in the corresponding exit subgraph set.

[0027] Repeat the above steps until all the subgraphs served by the exit nodes are identified, and output each exit node and the subgraph set it serves;

[0028] Step 5: Calculate indicators and evaluate network balance:

[0029] Input the subgraph set served by each outlet obtained in step 4, and calculate the outlet load index Q k Calculation formula to calculate the load index of each outlet;

[0030] Export load index Q k represents the evacuation load brought by all nodes i served by exit node k, which mainly considers the evacuation pressure caused by spatial area and personnel density on the exit. The larger the weight of node i and the smaller the weight of exit k, the greater the evacuation load. k represents the evacuation load brought by all nodes served by the exit node k; G is the subset of nodes served by the exit node k; w k is the weight of the exit node k; w i is the weight coefficient of node i;

[0031]

[0032] Input the load index Q of each outlet obtained in step 5 k , calculate the overall balance index of the network according to the balance index EBS formula to evaluate the evacuation balance of the building space;

[0033] The evacuation balance index EBS is used to evaluate the load balance level of all safety exits in the building space. The lower the value, the higher the balance of the evacuation exits. Among them, EBS is used to evaluate the balance level of the evacuation exits in the building space; k is the number of evacuation exit nodes; Q a represents the export load of the a-th export node; E m Indicates all export loads Q m The maximum value, or Q m =maxQ a ;

[0034]

[0035] Step 6: Node attack and stability analysis:

[0036] Using the node attack method, the changes in export load and balance before and after the node attack are calculated to reflect the security and stability level of the evacuation network;

[0037] Input the weighted network graph drawn in step 3, randomly delete any node to get a new network graph, repeat step 4, and divide the new network into each exit service subgraph after the node is attacked;

[0038] Repeat step 5 to calculate the load index Q of each exit of the new network after the node is attacked. a,after , and the post-attack balance indicator EBSafter , and calculate the change sensitivity index of the node

[0039] Change Sensitivity Index It is used to reflect the average change of each export load index before and after the node i is attacked. The larger the value, the greater the impact of the attack on node i on all exports. is the change sensitivity index of node i, which indicates the average change of each exit load index before and after the node i is attacked; k represents the number of evacuation exit nodes; Q a,before is the pre-attack load index of exit a; Q i,after The load index of exit a in the new path state after the attack on node i;

[0040]

[0041] Repeat step 6 until all nodes have been attacked once;

[0042] Statistically analyze the changes in network indicators after different nodes are attacked. Based on the weighted network diagram drawn in step 3, output a heat map of node change sensitivity by assigning nodes different sizes and colors.

[0043] Analyze the intensity and trend of changes in the balance level and evaluate the stability of the overall network structure.

[0044] Compared with the prior art, the present invention has the following beneficial effects:

[0045] 1. The present invention comprehensively evaluates evacuation performance: through the exit load index, balance index and sensitivity index, the evacuation balance level and safety stability level of the building space can be quantitatively evaluated, and the key nodes that affect the overall evacuation performance can be found.

[0046] 2. The workflow and code of this invention are written based on the open source Python language NetworkX library, providing a simple, fast and easy-to-learn analysis tool for evacuation assessment, evacuation management strategy formulation and architectural design.

[0047] 3. The present invention improves the efficiency of evaluation work: weighted network analysis is combined with programming to traverse the destruction possibilities of all nodes, reducing the number of repeated simulations and modeling time.

[0048] 4. The present invention optimizes building evacuation performance: safety stability level analysis and node attack analysis provide a scientific basis for optimizing the design of building evacuation paths and strengthening the protection of key nodes. BRIEF DESCRIPTION OF THE DRAWINGS

[0049] The accompanying drawings are used to provide a further understanding of the present invention and constitute a part of the specification. Together with the embodiments of the present invention, they are used to explain the present invention and do not constitute a limitation of the present invention. In the accompanying drawings:

[0050] Figure 1 It is a schematic diagram of the overall process of the present invention;

[0051] Figure 2 It is a schematic flow chart of a specific embodiment of the present invention; DETAILED DESCRIPTION

[0052] The preferred embodiments of the present invention are described below with reference to the accompanying drawings. It should be understood that the preferred embodiments described herein are only used to illustrate and explain the present invention, and are not used to limit the present invention.

[0053] Example 1

[0054] like Figure 1-2 As shown, the present invention provides a building space evacuation performance evaluation method based on a weighted network. The present invention will be further described below in conjunction with specific embodiments, but the present invention is not limited to the embodiments.

[0055] Example: Evacuation performance evaluation process of a primary school teaching building.

[0056] Step 1: Based on the floor plan of a primary school teaching building, process the architectural space information;

[0057] Step 2: Based on the basic principles of architectural space-topological network translation, the architectural space information generated in step 1 is processed to construct a topological network model of the architectural space;

[0058] Step 3: Calculate the weights of all nodes in the topological network formed in step 2 and draw a weight network diagram;

[0059] Step 4: Input the weighted network graph formed in step 3, compare the shortest path lengths from each node to each exit, and divide each exit into service subgraph sets;

[0060] Step 5: Input the subgraph set served by each outlet obtained in step 4, and calculate the load index of each outlet and the network balance evaluation;

[0061] Step 6: Input the weighted network graph formed in step 3, randomly delete any node to perform node attack, analyze the changes in its network indicators, and evaluate the network security and stability.

[0062] In this embodiment, the specific implementation process of obtaining and processing building space information in step 1 includes:

[0063] (1) Obtain the floor plan of a certain floor of the primary school teaching building, including but not limited to the schematic design drawings, the completed building surveying drawings, etc., simplify the architectural space information in the plan, and focus on the area of each space, space function, occupant density, evacuation safety exit location and other information;

[0064] (2) Determine the spatial connection relationship, including but not limited to corridor connection, door connection, hall connection and other connection methods;

[0065] In this embodiment, the specific implementation process of constructing the topological network model of the building space in step 2 includes:

[0066] (1) According to the basic principles of architectural space-topological network translation of “spatial continuity, spatial homogeneity, and spatial connection”, the space should be complete and continuous without interruption, the spatial nodes should be divided mainly by convex spaces, the interior of the space should be homogeneous and distinguishable from the adjacent areas, and the space should be connected to the adjacent space through doors, corridors, halls, openings, etc., so that people can pass through normally;

[0067] (2) Based on the basic principles of architectural space-topological network translation, the architectural space is divided into nodes and edges. Nodes represent spatial units such as rooms, corridors, stairs, and emergency exits, and edges represent direct connectivity between spaces. Draw a topological network diagram.

[0068] (3) For buildings with a large number of corridors, such as primary school teaching buildings, the focus of spatial node division is on the reasonable division of corridors. Combined with the basic characteristics of nearby evacuation, the corridor space is divided into multiple spatial nodes that can distinguish the evacuation direction, mainly including the two end nodes and the middle node. The node division should be as uniform as possible to show the proximity relationship between rooms in different positions and exits, reflecting the differences in evacuation paths.

[0069] (4) Based on the building plan information, the building space information generated in step 1 is processed, and all nodes and edges are numbered. The numbers cannot be repeated; the name types of different nodes are identified, including but not limited to exits, rooms, paths, etc., and Gephi 0.9.5 is used to draw a topological network diagram;

[0070] In this embodiment, the specific implementation process of drawing the weighted network diagram in step 3 includes:

[0071] (1) The nodes in the evacuation network have two key indicators: functional attributes and area scale. The weight coefficient of the node w i It reflects the importance of space, corresponding to the density and number of people. Generally speaking, nodes with larger areas and higher density of people are more important.

[0072] (2) Based on the population density α i , area scale β iTo determine the influencing factors, scenarios were established through evacuation simulation, and evacuation time data was obtained. The relationship between the two factors and evacuation time was analyzed. Combined with relevant building codes and cases, the population density value range was set to 0.2-1.2 people / ㎡, and the area size range was set to 100-600㎡, which can meet the design requirements of most types and functions of building spaces.

[0073] (3) Linear regression analysis was performed using population density and room area as independent variables and evacuation time as the dependent variable. The model formula after analysis was: evacuation time = -71.366 + 121.437 population density + 0.291 room area (R 2 =0.859, p=0.000<0.01), the model passed the F test (F=82.540, p=0.000<0.05), and the standardized coefficient Beta values of the two independent variables were similar (0.658, 0.653), indicating that the two variables had almost the same impact on the evacuation time results;

[0074] (4) Node weight w i The calculation formula is: i =α i *β i , where α i is the area scale normalized value of node i, β i is the normalized value of the personnel density of node i. The area and personnel density data of spatial nodes are processed using the maximum-minimum normalization method;

[0075] (5) Calculate the weights of all nodes in the topological network formed in step 2 in sequence, draw a sparse weight network graph based on this, and output the weight network graph in the .graphml format;

[0076] In this embodiment, the specific implementation process of dividing each egress service sub-graph set in step 4 includes:

[0077] (1) Input the weighted network graph drawn in step 3 and identify the shortest path between any non-exit node and all exit nodes;

[0078] (2) Calculate the length of each shortest path, select the shortest path after comparison, and include the node in the subgraph set served by the exit. If the number of shortest paths is greater than 1, the node weight is evenly divided and included in the corresponding exit subgraph set;

[0079] (3) Repeat the above steps until all the subgraphs served by the exit nodes are identified, and output each exit node and the subgraph set it serves;

[0080] In this embodiment, the specific implementation process of calculating the load index of each outlet and network balance in step 5 includes:

[0081] (1) Input the subgraph set served by each outlet obtained in step 4, and calculate the outlet load index Q k Calculation formula to calculate the load index of each outlet;

[0082] Export load index Q k It represents the evacuation load brought by all nodes i served by exit node k, which mainly considers the evacuation pressure caused by spatial area and population density on the exit. The larger the weight of node i and the smaller the weight of exit k, the greater the evacuation load. k represents the evacuation load brought by all nodes served by the exit node k; G is the subset of nodes served by the exit node k; w k is the weight of the exit node k; w i is the weight coefficient of node i;

[0083]

[0084] (2) Input the export load index Q obtained in step 5(1) k , calculate the overall balance index of the network according to the balance index EBS formula to evaluate the evacuation balance of the building space;

[0085] The evacuation balance index EBS is used to evaluate the load balance level of all safety exits in the building space. The lower the value, the higher the balance of the evacuation exits. Among them, EBS is used to evaluate the balance level of the evacuation exits in the building space; k is the number of evacuation exit nodes; Q a represents the export load of the a-th export node; E m Indicates all export loads Q m The maximum value, or Q m =maxQ a .

[0086]

[0087] In this embodiment, the specific implementation process of analyzing network security stability through node attacks in step 6 includes:

[0088] (1) Input the weighted network graph formed in step 3, randomly delete any node to perform node attack, randomly delete any node to obtain a new network graph, repeat step 4, and divide the node after the attack into each exit service subgraph of the new network;

[0089] (2) Repeat step 5 to calculate the load index Q of each outlet of the new network after the node is attacked. a,after , and the post-attack balance indicator EBS after , and calculate the change sensitivity index of the node

[0090] Change Sensitivity Index It is used to reflect the average change of each export load index before and after the node i is attacked. The larger the value, the greater the impact of the attack on node i on all exports. is the change sensitivity index of node i, which indicates the average change of each exit load index before and after the node i is attacked; k represents the number of evacuation exit nodes; Q a,before is the pre-attack load index of exit a; Q i,after Load indicator of exit a in the new path state after node i is attacked.

[0091]

[0092] Repeat step 6 until all nodes have been attacked once;

[0093] Statistically analyze the changes in network indicators after different nodes are attacked. Based on the weighted network diagram drawn in step 3, output a heat map of node change sensitivity by assigning nodes different sizes and colors.

[0094] Analyze the intensity and trend of changes in the balance level and evaluate the stability of the overall network structure.

[0095] Finally, it should be noted that the above descriptions are merely preferred embodiments of the present invention and are not intended to limit the present invention. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art will be able to modify the technical solutions described in the aforementioned embodiments or substitute equivalents for some of the technical features. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention shall be included within the scope of protection of the present invention.

Claims

1. A building space evacuation performance evaluation method based on weighted network, characterized in that: The following steps are involved: Step 1: Processing architectural space information: Select a typical building plan and simplify it, clarify the area, function, occupancy density, and location of evacuation exits of each space, and determine the spatial connections, including but not limited to corridor connections, door connections, and hall connections; Step 2: Construct a topological network model of the building space: According to the basic principles of architectural space-topological network translation, the architectural space is divided into nodes and edges. Nodes represent rooms, corridors, stairs, and emergency exit space units, while edges represent direct connectivity between spaces. Draw a topological network diagram. Identify the name types of exits, rooms, and path nodes, and use Gephi 0.9.5 to draw the topological network diagram; Step 3. Calculate node weights and draw a weighted network diagram: Calculate all node weights in turn, node weight w i The calculation formula is: i =α i ×β i , where α i is the area scale normalized value of node i, β i is the normalized value of the personnel density of node i. The area and personnel density data of spatial nodes are processed using the maximum-minimum normalization method; Based on the topological network diagram drawn in step 2, draw the evacuation weight network diagram and output the weight network diagram in the .graphml format; Step 4: Divide each export service subgraph: Input the weighted network graph drawn in step 3 and identify the shortest path between any non-exit node and all exit nodes; Calculate the length of each shortest path, compare and select the shortest path, and include the node in the subgraph set served by the exit. If the number of shortest paths is greater than 1, the node weight is evenly distributed and included in the corresponding exit subgraph set. Repeat the above steps until all the subgraphs served by the exit nodes are identified, and output each exit node and the subgraph set it serves; Step 5: Calculate indicators and evaluate network balance: Input the subgraph set served by each outlet obtained in step 4, and calculate the outlet load index Q k Calculation formula to calculate the load index of each outlet; Export load index Q k represents the evacuation load brought by all nodes i served by exit node k, which mainly considers the evacuation pressure caused by spatial area and personnel density on the exit. The larger the weight of node i and the smaller the weight of exit k, the greater the evacuation load. k represents the evacuation load brought by all nodes served by the exit node k; G is the subset of nodes served by the exit node k; w k is the weight of the exit node k; w i is the weight coefficient of node i; Input the load index Q of each outlet obtained in step 5 k , calculate the overall balance index of the network according to the balance index EBS formula to evaluate the evacuation balance of the building space; The evacuation balance index EBS is used to evaluate the load balance level of all safety exits in the building space. The lower the value, the higher the balance of the evacuation exits. Among them, EBS is used to evaluate the balance level of the evacuation exits in the building space; k is the number of evacuation exit nodes; Q a represents the export load of the a-th export node; E m Indicates all export loads Q m The maximum value, or Q m =maxQ a ; Step 6: Node attack and stability analysis: Using the node attack method, the changes in export load and balance before and after the node attack are calculated to reflect the security and stability level of the evacuation network; Input the weighted network graph drawn in step 3, randomly delete any node to get a new network graph, repeat step 4, and divide the new network into each exit service subgraph after the node is attacked; Repeat step 5 to calculate the load index Q of each exit of the new network after the node is attacked. a,after , and the post-attack balance indicator EBS after , and calculate the change sensitivity index of the node Change Sensitivity Index It is used to reflect the average change of each export load index before and after the node i is attacked. The larger the value, the greater the impact of the attack on node i on all exports. is the change sensitivity index of node i, which indicates the average change of each exit load index before and after the node i is attacked; k represents the number of evacuation exit nodes; Q a,before is the pre-attack load index of exit a; Q i,after The load index of exit a in the new path state after the attack on node i; Repeat step 6 until all nodes have been attacked once; Statistically analyze the changes in network indicators after different nodes are attacked. Based on the weighted network diagram drawn in step 3, output a heat map of node change sensitivity by assigning nodes different sizes and colors. Analyze the intensity and trend of changes in the balance level and evaluate the stability of the overall network structure.

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