Adaptive decision-making in buildingEXODUS in response to exit congestion

Given the importance of occupant behavior on evacuation efficiency, a new behavioral feature has been implemented into building EXODUS. This feature concerns the response of occupants to exit selection and re-direction, given that the occupant is queuing at an external exit. This behavior is not simply pre-determined by the user as part of the initialization process, but involves the occupant taking decisions based on their previous experiences with the enclosure and the information available to them. This information concerns the occupant's prior knowledge of the enclosure and line-of-sight information concerning queues at neighboring exits. This new feature is demonstrated and reviewed through several examples.

Traffic policing in ATM networks with multimedia traffic: the super leaky bucket

Traffic policing and bandwidth management strategies at the User Network Interface (UNI) of an ATM network are investigated by simulation. The network is assumed to transport real time (RT) traffic like voice and video as well as non-real time (non-RT) data traffic. The proposed policing function, called the super leaky bucket (S-LB), is based on the leaky bucket (LB), but handles the three types of traffic differently according to their quality of service (QoS) requirements. Separate queues are maintained for RT and non-RT traffic. They are normally served alternately, but if the number of RT cells exceeds a threshold, it gets non-pre-emptive priority. Further increase of the RT queue causes low priority cells to be discarded. Non-RT cells are buffered and the sources are throttled back during periods of congestion. The simulations clearly demonstrate the advantages of the proposed strategy in providing improved levels of service (delay, jitter and loss) for all types of traffic.

Advanced evacuation simulation software and its use in warships

The newly formed Escape and Evacuation Naval Authority regulates the provision of abandonment equipment and procedures for all Ministry of Defence Vessels. As such, it assures that access routes on board are evaluated early in the design process to maximize their efficiency and to eliminate, as far as possible, any congestion that might occur during escape. This analysis can be undertaken using a computer-based simulation for given escape scenarios and replicates the layout of the vessel and the interactions between each individual and the ship structure. One such software tool that facilitates this type of analysis is maritimeEXODUS. This tool, through large scale testing and validation, emulates human shipboard behaviour during emergency scenarios; however it is largely based around the behaviour of civilian passengers and fixtures and fittings of merchant vessels. Hence there existed a clear requirement to understand the behaviour of well-trained naval personnel as opposed to civilian passengers and be able to model the fixtures and fittings that are exclusive to warships, thus allowing improvements to both maritimeEXODUS and other software products. Human factor trials using the Royal Navy training facilities at Whale Island, Portsmouth were recently undertaken to collect data that improves our understanding of the aforementioned differences. It is hoped that this data will form the basis of a long-term improvement package that will provide global validation of these simulation tools and assist in the development of specific Escape and Evacuation standards for warships. © 2005: Royal Institution of Naval Architects.

The impact of the passenger response time distribution on ship evacuation performance

The International Maritime Organisation (IMO) has adopted the use of computer simulation to assist in the assessment of the assembly time for passenger ships. A key parameter required for this analysis and specified as part of the IMO guidelines is the passenger response time distribution. It is demonstrated in this paper that the IMO specified response time distribution assumes an unrealistic mathematical form. This unrealistic mathematical form can lead to serious congestion issues being overlooked in the evacuation analysis and lead to incorrect conclusions concerning the suitability of vessel design. In light of these results, it is vital that IMO undertake research to generate passenger response time data suitable for use in evacuation analysis of passenger ships. Until this type of data becomes readily available, it is strongly recommended that rather than continuing to use the artificial and unrepresentative form of the response time distribution, IMO should adopt plausible and more realistic response time data derived from land based applications. © 2005: Royal Institution of Naval Architects.

Extended model of pedestrian escalator behaviour based on data collected within a Chinese underground station

This paper presents data relating to pedestrian escalator behaviour collected in an underground station in Shanghai, China. While data was not collected under emergency or simulated emergency conditions, it is argued that the data collected under rush-hour conditions - where commuters are under time pressures to get to work on time - may be used to approximate emergency evacuation conditions - where commuters are also under time pressures to exit the building as quickly as possible. Data pertaining to escalator/stair choice, proportion of walkers to riders, walker speeds and side usage are presented. The collected data is used to refine the buildingEXODUS escalator model allowing the agents to select whether to use an escalator or neighbouring parallel stair based on congestion conditiions at the base of the stair/escalator and expected travel times. The new model, together with the collected data, is used to simulate a series of hypothetical evacuation scenarios to demonstrate the impact of escalators on evacuation performance.

The vague, the viral, the parasitic: Piranesi's metropolis

In mid-18th century Giovanni Battista Piranesi’s etchings systematically document the old and new monuments, decrepit buildings and broken down infrastructures of a Rome that continues to inhabit and reinvent its past. His views of Rome offer a devastating account of the blurring of distinctions and articulations that time, use and neglect have imposed on the old differentiations of the urban and the rural, the public and the private, the monumental and the domestic in the 18th century city. Rome becomes for Piranesi the laboratory for a questioning of architecture that places his work well beyond the debate on style and on the origin that dominated the architectural discourse of his time. This paper suggests that Piranesi’s images anticipate the dispersion and sprawl of the city of today, in which the ‘vague’, the ‘viral’ and the ‘parasitic’ become modes of inhabitation and of transient negotiated definition. In the Antichità di Roma, ancient buildings are represented not only in their large scale and magnificence, but also in their decay and reversal to a state of naturalness. These works, together with the acute observations of the Vedute di Roma, provide the materials that are then dislocated, manipulated, cloned and endlessly mutated by Piranesi in the synthesis of the Campo Marzio dell’Antica Roma, in which the historical city is almost entirely dissolved and replaced by an extraordinary congestion of fragments. When they are re-examined on the grounds of contemporary architectural and urban theory, the sites of Piranesi's views reveal anticipations of phenomena that affect the metropolis of today. Political, social and economic conditions have changed dramatically, but the questions asked of architecture in and by these sites challenge the definition of an architecture of style, forms and boundaries - in the 18th century as well as in the 21st -in favour of an architecture of change.