Publication Type: Conference Paper
Source: Pedestrian and Evacuation Dynamics PED 2012 (2012)
Increasing population and the trend of urbanisation results in more and more densely populated cities. Managing the increasing number of people in cities efficiently has become priority for many city governments. While urbanisation has many advantages it comes with its own problems. Most (if not all) large cities have to deal with problems that are typical for their size and density such as traffic jams, for example. Smart traffic systems can help to alleviate the problems to some extent. Another consequence of increasing population density in cities are high-floor buildings (e.g., office towers, mega shopping malls, high-rise residential buildings) that provide shelter, office space, entertainment, and recreation for thousands of people. Although buildings have to satisfy certain safety standards by design, for example by featuring well-displayed emergency exits and well-located fire extinguishers, the large number of occupants may cause significant congestion in case of a necessary evacuation due to events such as fire.
Technology can help to make operations more efficient and egress is no exception. In fact, as we will show in this paper, egress is a good example where technology can make a positive difference. Buildings are typically equipped with floor plans that show emergency exits and evacuation routes to the nearest exit. While such a static guidance system can give people a general idea where they are currently located and where the nearest exit is, it cannot provide guidance that adapts dynamically to the current situation. In case of an emergency, a situation may become very dynamic for various reasons such as rapid spread of fire and smoke, congested evacuation routes, blocked exits, or even panic. The ability to capture information about a situation in real-time represents an important advantage that can help to make egress more efficient. Smart buildings can be equipped with various forms of sensors (e.g., smoke detectors, heat detectors, motion detectors) and actuators (e.g., electronic sign-boards) that can be utilized by a guidance system. This guidance system can use real-time sensor data to dynamically adapt to the current situation and provide useful information (e.g., direction to the nearest/safest exit) to the evacuees by means of various actuators.
Given information about the current situation in the building, the guidance system can compute the preferred route to an exit from any location in the building. There are a number of challenges that need to be considered and adequately addressed. One important issue, that we will address in our work, is concerned with the dynamics of an emergency situation. We are concerned with dynamics that arise from the rapid spread of fire and smoke as well as human crowd behaviour. In particular, crowd dynamics may lead to congestions and bottle-necks in certain parts of the building. Although, a reactive zero-lookahead guidance system can probably take into consideration the number of people in the various parts of the building as well as the current location of the fire(s) in order to determine an ideal route in order to avoid congestion, it lacks predictive capabilities. This can be a serious disadvantage and may even exacerbate certain problems. In this paper, we propose a simulation-based guidance system in a smart building environment. This system makes use of high-fidelity simulations that enable it to predict how the emergency unfolds in the near-future. For this purpose, we will utilize ideas from the field of symbiotic simulation [1,2].
Symbiotic simulation is a paradigm in which a physical system and a simulation system are closely coupled by sensors and actuators. This relationship is often mutually beneficial. The simulation system benefits from real-time sensor data which makes it possible to perform high-fidelity simulations of the physical system. The physical system, on the other hand, benefits from the outcome of what-if analyses conducted by the simulation system. The purpose of such a what-if analysis depends on the application. Here, we describe a smart building application where the guidance system is based on a symbiotic simulation system. Therefore, in this particular application, the symbiotic simulation system is concerned with a decision making problem: which is the best evacuation path at a particular time in a specific part of the building? The symbiotic simulation system is capable of evaluating alternative routes (e.g., what-if scenarios) by means of simulation as the egress event progresses. The ability of a symbiotic simulation system to simulate many possible what-if scenarios, enable the guidance system to analyse various possible solutions and select the one which provides the best performance (in terms of evacuation time or safety, for example).
In this paper, we demonstrate the effectiveness of the symbiotic simulation-based approach through various experiments. The experiments highlight the situations in which a smart building, equipped with an active guidance system, can be most effective in helping people escape from a building. These experiments are performed using an agent-based crowd model. For the simulated building, we consider a typical multi-storey office building. More specifically, the building model is adapted from publicly available floor plans of the World Trade Center in Long Beach, California.