Optimization Based Controlled Evacuation Using Pedestrian Speed-Density Relationship: A Case Study Of Universiti Sains Malaysia
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Date
2015-10
Authors
KAWSAR, LUTHFUL ALAHI
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Abstract
The speed-density relationship is a major concern in the study of the
evacuation of facilities, as it is linked directly with the capability of a walkway to
keep up a preferred flow of pedestrians along its length. This research aims to
determine an improved speed-density relationship model for pedestrian flow that
takes into account the decay rate of speed for an increase in density and formulate an
efficient control methodology which can help to maintain a smooth and quick
evacuation during an emergency. The Dewan Tuanku Syed Putra (DTSP) hall room
of Universiti Sains Malaysia is considered as a case study. The M/G/c/c state
dependent queueing model is used to evaluate the performance measures of the
DTSP network. The result shows that the maximum throughput can be obtained by
putting some restrictions on the travelling direction from the source walkways to the
exiting walkways. Data from the DTSP hall room was collected from each session
during the convocation from 21st to 25th September 2011 using a photographic
procedure. The validity of the improved speed-density relationship model has been
verified by fitting it to the primary dataset and eight different secondary datasets.
The results show that the model explains the speed-density relationship well for all
the datasets (all 0.78 2 R ). Using the conservation of mass concept, a novel
controlled flow methodology based on a linear programming problem is developed
for computing the optimal flow rates for a multi-exit evacuation network. In an
emergency situation, the controlled flow design is able to track the values of the
walkway density, the number of occupants in nodes and thus assures that the flow
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from adjacent sources to the source walkways is at their maximum level. Using the DTSP hall room as a multi-exit network, a simulation of the flow shows that the source walkways are blocked when there is an uncontrolled flow. Hence, very few occupants can make their way into the intermediate walkways and exits. For the controlled flow, the values of occupant density in the source and intermediate walkways gradually approach the critical density, ensuring a maximum flow. A perturbation study of the controlled flow methodology for the different values of the decay rate of speed gives stable results in terms of the state and control variables. The developed methodology is useful for the architects and disaster management authorities who are concerned with the evacuation of building facilities and can be used as a paradigm for future studies.
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Optimization Based Controlled Evacuation Using Pedestrian Speed-Density Relationship , A Case Study Of Universiti Sains Malaysia