A concept from computer science. An agent is an autonomous entity interacting with its environment and other agents. A pedestrian in the simulation is an agent.
ASEP Asymmetric simple exclusion process. A discrete model for transport phenomena, where a particle is allowed to hop to the neighboring lattice sites. The NaSch–model with vmax = 1 is equivalent to the (totally)

Assembly phase

The evacuation procedure on passenger ships is divided into two separate phases: assembly phase and embarkation phase. First, the passengers gather at the assembly points and then proceed to the embarkation stations, if the decisionto abandon the ship is made.

Assembly stations

Areas on-board a ship where the passengers gather in case of an alarm. Every passenger is assigned to a specific assembly station. (See also: assembly phase).

Awareness time

The time it takes to detect an incident and decide to take action is called awareness time. It is therefore rather a global than an individual variable. Cellular Automaton A lattice, a finite set of states, the definition of a neighborhood
and an update function (L, S, N, f) are called a cellular automaton.


A gathering of two or more persons. Crowds are different from groups because they persist only for a short time, are at the same place, and share a common focus.

Crowd Dynamics

Crowd motion together with the influencing factors.

Crowd Control

Reactive measures (used, e.g., by the police) to enforce the desired behavior of a crowd.

Crowd Management

Proactive and precautionary measures (e.g., procedural or concerning the layout of a building) to direct crowd movement and behavior into the desired way. The aim of crowd management is to increase the comfort on the one hand and to avoid the necessity for crowd control on the other hand. Crowd Motion Movement of a crowd determined by physical, physiological, psychological, and social factors.

Continuous model

A model in which time and space are represented by continuous variables, i.e., variables that can take real numbers as values. Macroscopic models are usually continuous, microscopic models might be continuous or discrete.

Directional Sound

is a system of sound beacons which are understood intuitively and guide person to the exit. Since it is based on sound, it is not obscured by smoke.

Discrete model

A model in which space and time are discrete, i.e., the corresponding variables take on integer numbers. Discrete models are usually microscopic. Egress Leaving a building, vessel, or place by a group or an individual. Opposite to evacuation, egress occurs in normal and emergency situations.


Entering the life-boats, resp. the life-rafts via the slides.

Embarkation time

In the simulation an individual embarkation time tembark can be specified. It is usually assumed to be the same for everyone. This time represents either the time to enter the life-boat or the raft via a slide. Alternatively an overall embarkation time E can be used that covers the embarkation of all the persons. (See also: Launching time below).


Egress due to a potential or actual hazard (emergency egress).

Evacuation curve

The number of persons evacuated vs. time n(t). This curve allows to assess the evacuation, since it contains the information about the total number of persons, the overall time, and the flow vs. time can be obtained by taking the derivative.


A graph is a set of vertices and edges, where each edge connects two vertices. A (regular) lattice is a certain type of planar graph, where each vortex is connected to the same number of other vertices (coordination umber). Cellular automata are based on regular lattices (usually a square grid).

High Speed Passenger Craft (HSC)

are fast passenger ferries usually covering only short distances. The seating arrangement is similar to aircraft and they are evacuated via slides and life-rafts.


International Maritime Organization, sub-organization of the UNO, London.


Transformation of a model into a set of algorithms formulated in a programming language.


is understood as the formulation of a model that is consistent with a theory (e.g., a discrete, microscopicmodel based on the general theory for crowd motion). This is done by formulating the assumptions of the theory in a quantitative way and removing ambiguities without loosing consistency. In the context of interpreting simulation results, there is a second meaning: connecting simulation results to real world phenomena.

Launching time

is the time it takes to launch the life-boats. In the evaccuation analysis for passenger vessels, the sum of embarkation and launching time can be set to 30 minutes, if no data are available.

Low location lighting

Band of small arrows at the floor which directs persons crawling to the exit (usually phosphorescent). LLL is required for aircraft and by SOLAS for ships.