Applied Mathematical Sciences, Vol. 8, 2014, no. 104, 5163-5172 HIKARI Ltd, www.m-hikari.com http://dx.doi.org/10.12988/ams.2014.45384 Simulation Method of Shortest and Safest Path Algorithm for Evacuation in High Rise Building Nor Amalina Mohd Sabri Center for Advanced Computing Technology (C-ACT) Faculty of Information and Communication Technology Universiti Teknikal Malaysia Melaka, Malaysia Abd Samad Hasan Basari Center for Advanced Computing Technology (C-ACT) Faculty of Information and Communication Technology Universiti Teknikal Malaysia Melaka, Malaysia Burairah Husin Center for Advanced Computing Technology (C-ACT) Faculty of Information and Communication Technology Universiti Teknikal Malaysia Melaka, Malaysia Khyrina Airin Fariza Abu Samah Center for Advanced Computing Technology (C-ACT) Faculty of Information and Communication Technology Universiti Teknikal Malaysia Melaka, Malaysia Copyright 2014 Nor Amalina Mohd Sabri et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. Abstract The objectives of this research are to identify the suitable shortest and safest path algorithm for evacuation, and followed by design and develop an evacuation preparedness model simulation via shortest path algorithm to choose a suitable exit route to evacuate the evacuees. These objectives have been carried out to overcome the problem of difficulties faced by the evacuees to find the best routes
5164 Nor Amalina Mohd Sabri et al. including shortest and safest path. Five steps of methods are brought out to achieve the objectives by implementing the Dijkstra Algorithm. The first step is importing the matrix data followed by input the source and destination ID. Third step is to generate the shortest path, the fourth is removed the edges and finally generate the safest path. This research is concentrating on high rise building during critical incident and evacuation. The preliminary result has shown an encouraging result which can provide the shortest and safest path for the evacuees. Keywords: Critical Incident; Dijkstra Algorithm; Shortest and Safest Path 1 Introduction Evacuation planning is an important issue that should be considered while designing the building layout, especially to those complexes and high rise building. The building should follow the rules that have been strict by the safety authorities in order to take more concern regarding the safety and evacuation of the building. Nowadays, majority of the building give less priority on the design of the building towards the safety of occupants. The most important to them is the design of the building and not the safety of the building. This norm is affecting the process of evacuation if any hazard occurs in the building. Occurring of hazard is unexpected and preparation should take place frequently and continuously. Hazard can be unexpectedly occurred such as presence of fire in the building, earthquakes, tornadoes and attacking from any villain. Presence of hazard in a close and high rise building is a serious matter to be considered. Especially the hazards happen in the building that visited with new visitors such as government office and shopping mall. The new visitors are unable to find the exit route in the building as their taken route has been blocked due to ongoing hazard. The good evacuation planning has to carry out to overcome the problem of finding the shortest path as the evacuees had the difficulties to find the way out [1]. This problem will bring the problem related to the behavior of the evacuees which make the process more difficult. Evacuees are panicked to find the exit route in that critical situation as everybody want to save themselves without thinking of the others. Hence, finding the shortest and safest way is very important [2]. Currently, modern building tend to be complex, large scale and multifunctional [3], it is because building design intensely influences the process of searching the shortest path. Subsequently, evacuees will act various behavior when they hard to find the exit way due to complexness of the building. Making a decision in a critical time seldom produces a good decision. This is because their minds are controlled by mix of emotions and unable to decide properly. Supposedly, decision making has to be made quickly to reduce the
Simulation Method of Shortest and Safest Path Algorithm 5165 time taken in the evacuation process. Moreover, it helps to minimise the injuries of evacuees in the ongoing hazard. To those evacuees who are unfamiliar with the building are hard to find the safe route as the route change due to the spreading of hazard [4]. To overcome this issue, evacuees have to pay attention and follow the evacuation process to successfully find the shortest and safest route [5]. Due to this problem, a good evacuation management should be carried out. A good evacuation management should also consider the presence of hazard during the evacuation as the route will be no longer useable to evacuees towards exit route. If the hazard detected in the exit way, another alternative route has to be proposed to save the evacuees from any danger. This shows the important of choosing the short and safest route. Hence, this research proposed two objectives which are identifying the efficient shortest and safest path algorithm for evacuation. Secondly is followed by design and develop evacuation preparedness model via shortest path algorithm on exit route selection to evacuate. Expectation of this research is to produce independent evacuation preparedness algorithm for exit route in order to guide evacuees to discharge from the building safely. It is more efficient to evacuate evacuees from danger to safe place especially to evacuees who is unfamiliar with the building. They need to follow the guide and escape safely [6] to overcome evacuee problem in finding the shortest and safest route. The contribution in this study is guiding the evacuees in easy and smooth to find the shortest route in a safest way and in consequences reduce injuries of evacuees during the evacuation. 2 Methodology This research methodology follows Dijkstra Algorithm for finding the shortestpath in the evacuation process in a high rise building. Dijkstra Algorithm has been chosen as it can efficiently produce the shortest path for selection of route. Moreover, it also can provide safer evacuation plan [7] [3] [8]. This scope of research is to find the shortest distance between a node and all other nodes and suit the Dijkstra Algorithm target [9] [10]. This technique also claims to be among the best approaches in solving simple shortest path problem and always provide shortest path from any evacuation node [11] [12]. Furthermore, Dijkstra Algorithm can solve the single sources shortest path problem in a graph as it is a graph search algorithm [13] [2]. This implementation of Dijkstra Algorithm involve five steps which are Import Matrix Data, Input Source and Destination ID, Generate Shortest Path, Remove Edge and Regenerate the Shortest Path as shown is Figure 1.
5166 Nor Amalina Mohd Sabri et al. Figure 1. Research Methodology. Simulation program has been built to find the shortest path in the selected layout building based on Dijkstra Algorithm calculation. The selected building is an office environment in a high rise building. As an office environment, the building layout is designed into variety of clustered room size as it can be an obstacle during the evacuation process. From the layout building, node and edge has been created. Every door in the building represent node and the distance between the nodes are called weight for each edge. Nevertheless, window are not selected as a node, because window are not the exit way from the building and do not have any important role in a high rise building. Staircase is a pointed or destination node as it is the last exit way to get out from the building safely. The data are transformed into a matrix data as it can be easily imported to the simulation program. The simulation program read the data to plot the route of the building in a Visibility graph. The Visibility graph are another view of building route as it can be easily understand by displaying the relationship of nodes and edges. The relationship is connected either in two or one way based on the weight from the matrix data. Second step is input the variable for source ID and destination ID. Source ID is defined as current position of the evacuees and destination ID is a safest place or exit way for the evacuee to walk out of the building. As been told before, staircase will be setup as a destination ID in this high rise building. The total distance will be calculated by the simulation program based on taken path from input source ID to destination ID. Together with step 2, shortest path will be generated based on the input from step 2. The shortest path will be calculated based on the weight of the edges from the relationship of nodes and edges as displayed in the visibility
Simulation Method of Shortest and Safest Path Algorithm 5167 graph. Calculation of the shortest path is based on the utilisation of Dijkstra Algorithm in the program. In consideration for the presence of hazard during the evacuation, the activeness of the node will be affected. If the hazard occur in the node or near the node, the path connected into the node is no longer safe. The evacuees are not able to pass the node and the alternative route will be given. The shortest path will change dynamically to update the safe route. The shortest and safest path will be generated after removing the danger path or edges in the visibility graph and shown the alternative path by considering the safety of the evacuees. 3 Results and Discussion By using the MATLAB program the shortest path has been produced based on the distance from source ID to destination ID. The result shows the calculated shortest paths based on the Dijkstra Algorithm and display the shortest path route in a graph. The graph indicates two colours of node to differentiate the taken path and the untaken path. (see Figure 2). Figure 2. Different Colours of Nodes Figure 2 shows that the red node is a taken path and the otherwise is untaken path. As for example, a calculation of distance of shortest path has been carried out between one source node and destination node. The chosen building is a high rise building which use staircases to be the destination node. As shown in the Table 1 and Figure 3 the result of shortest path has been calculated by the MATLAB program with embedded Dijkstra Algorithm.
5168 Nor Amalina Mohd Sabri et al. Table 1. Shortest Path Result. Figure 3. Shows visited node that has been taken for shortest path between source ID (Node 7) and destination ID (Node 49). The above result covered the shortest path with exception of safety of the route. As a comparison, Table 2 shows the result of the route with presence of hazard in the path that already taken in the shortest path in Table 1. Table 2 is calculated by considering the unexpected danger that happened on the way to destination node. The result of Table 2 and Figure 4 covers the shortest and safest path.
Simulation Method of Shortest and Safest Path Algorithm 5169 Table 2. Shortest and Safest Path Result. Figure 4. The MATLAB program will suggest another path to take in order to safely arrive to the destination node which is covers Shortest and Safest Path. Table 2 shows the result after blocking the node 8. Hence, node 9 and node 11 are taken as the alternative path. In comparison, the distances of the route are different as some of the taken paths are not able to use due to the unexpected danger. The MATLAB program will suggest another path to take in order to safely arrive to the destination node (refer to Figure 4). Even though the distance of safest paths are not short enough compared to the shortest path distance, it is recommended to use safest paths as it can save the evacuees to move out from the building safely.
5170 Nor Amalina Mohd Sabri et al. As compared between the visibility graph in Figure 4 and 2D building layout as shown in the Figure 5, after blocking node 8, node 9 and node 11 are suggested to reach the destination node. Figure 5. 2D Layout Building for Shortest and Safest Path. 4 Conclusions In this paper, shortest path and safest path has been discussed by using a MATLAB simulation program that utilise Dijkstra Algorithm. To generate the result, five steps of method had been applied. The first step is importing the matrix data into MATLAB simulation program followed by input the variable of source ID and destination ID. To accomplish the third steps, input of source ID and destination ID are used to generate shortest path. Second last step is removing the edges that affected into danger and proceed to last step by generating the safest path. For future improvements is enhancing the Dijkstra Algorithm by utilizing artificial intelligence (AI) method such as Ant Colony Optimization (ACO) and Particle Swarm Optimization (PSO). Acknowledgements. The authors would like to thank the Faculty of Information Technology and Communication (FTMK), Universiti Teknikal Malaysia Melaka (UTeM) for supporting this research. This research also part
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