Crowd Simulation

There are many architectural design parameters for public transport stations which include urban and station level studies. Each station must be designed in accordance with the basic passenger requirements such as accessibility, safety, comfort, satisfaction and etc. Circulation spaces must be formed and sized to meet the minimum movement needs of passengers. For an underground station; main entrance region, position of gates, location and number of turnstiles, escalators, stairs, ramps, passageways, intermediate concourses and platforms must be arranged to minimize walking distances and to prevent congestion. In this study, circulation of passengers is simulated in a quantitatively verifiable manner, taking into account how individuals interact with each other and with the physical obstacles in their environment in a metro station. Virtual experiments are performed to see the continuity and density of pedestrian flow at different levels of Haram Area East Metro Station of the first...

In this paper we model pedestrian flows evacuating a narrow corridor through an exit by a one-dimensional hyperbolic conservation law with a non-local constraint. Existence and stability results for the Cauchy problem with Lipschitz constraint are achieved by a procedure that combines the wave-front tracking algorithm with the operator splitting method. The Riemann problem with piecewise constant constraint is discussed in details, stressing the possible lack of uniqueness, self-similarity and L 1 loc -continuity. One explicit example of application is provided.

For the past two decades, historians and archaeologists have reconstructed heritage sites using computer-generated graphics in three dimensions, a technique known as “virtual archaeology.” Early research focused merely on displaying models of the architecture or of archaeological artifacts, but with the emergence of virtual worlds, researchers and the public can “immerse” themselves in the reconstructed environment and experience the equivalent of a guided tour. User-generated content has allowed historians to now go a step further and modify the models, by formulating hypotheses and testing them interactively, creating a “virtual laboratory of archaeology.” In this chapter, a solution is offered whereby historians are able to manipulate the parameters of a crowd simulation without the need of learning conventional computer programming. This conceptual framework is loosely based on strategy computer games, which also allow players to simulate relatively complex crowds by visually placing markers on the ground. It extends the concept of the virtual laboratory of archaeology beyond the architectural representation of heritage sites by placing the tools of crowd simulation in the hands of historians.

Simulation and visualization of emergent crowd in real-time is a computationally intensive task. This intensity mostly comes from the O(n 2 ) complexity of the traversal algorithm, necessary for the proximity queries of all pair of entities in order to compute the relevant mutual interactions. Previous works reduced this complexity by considerably factors, using adequate data structures for spatial subdivision and parallel computing on modern graphic hardware, achieving interactive frame rates in real-time simulations. However, the performance of existent proposals are heavily affected by the maximum density of the spatial subdivision cells, which is usually high, yet leading to algorithms that are not optimal. In this paper we extend previous neighborhood data structure, which is called neighborhood grid, and a simulation architecture that provides for extremely low parallel complexity. Also, we implement a representative flocking boids case-study from which we run benchmarks with simulation and rendering of up to 1 million boids at interactive frame-rates. We remark that this work can achive a minimum speeup of 2.94 when compared to traditional spatial subdivision methods with a similar visual experience and with lesser use of memory.

Real-time crowd simulation for virtual environment applications requires not only navigation and locomotion in large environments while avoiding obstacles and agents, but also rendering high quality 3D fully articulated figures to enhance realism. In this paper, we present a framework for real-time simulation of crowds. The framework is composed of a Hardware Accelerated Character Animation Library (HALCA), a crowd simulation system that can handle large crowds with high densities (HiDAC), and an Animation Planning Mediator (APM) that bridges the gap between the global position of the agents given by HiDAC and the correct skeletal state so that each agent is rendered with natural locomotion in real-time. The main goal of this framework is to allow high quality visualization and animation of several hundred realistic looking characters (about 5000 polygons each) navigating virtual environments on a single display PC, a HMD (Head Mounted Display), or a CAVE system. Results of several ...

Abstract: Fatal crush conditions occur in crowds with tragic frequency. Event organisers and architects are often criticised for failing to consider the causes and implications of crush, but the reality is that the prediction and mitigation of such conditions offers a significant technical challenge. Full treatment of physical force within crowd simulations is precise but computationally expensive; the more common method of human interpretation of results is computationally" cheap" but subjective and time-consuming. In this paper we propose an ...

There are many architectural design parameters for public transport stations which include urban
and station level studies. Each station must be designed in accordance with the basic passenger
requirements such as accessibility, safety, comfort, satisfaction and etc. Circulation spaces must be
formed and sized to meet the minimum movement needs of passengers. For an underground
station; main entrance region, position of gates, location and number of turnstiles, escalators,
stairs, ramps, passageways, intermediate concourses and platforms must be arranged to minimize
walking distances and to prevent congestion. In this study, circulation of passengers is simulated
in a quantitatively verifiable manner, taking into account how individuals interact with each other
and with the physical obstacles in their environment in a metro station. Virtual experiments are
performed to see the continuity and density of pedestrian flow at different levels of Haram Area
East Metro Station of the first metro line of Madinah Al-Munawwarah, Saudi Arabia. According
to the predictions, more than 40.000 passengers are expected to use this station in one hour after a
Friday prayer during Ramadan period in the year of 2040. That means a critically high travel
demand and it is really significant to design the most convenient underground station for these
passengers to fulfil the necessary requirements.

Simulating the motion of realistic, large, dense crowds of autonomous agents is still a challenge for the computer graphics community. Typical approaches either resemble particle simulations (where agents lack orientation controls) or are conservative in the range of human motion possible (agents lack psychological state and aren't allowed to 'push' each other). Our HiDAC system (for High-Density Autonomous Crowds) focuses on the problem of simulating the local motion and global wayfinding behaviors of crowds moving in a natural manner within dynamically changing virtual environments. By applying a combination of psychological and geometrical rules with a social and physical forces model, HiDAC exhibits a wide variety of emergent behaviors from agent line formation to pushing behavior and its consequences; relative to the current situation, personalities of the individuals and perceived social density.

In order to create plausible virtual humans it is important to model their movement and interactions with their environment in an accurate and realistic manner. A lot of time and effort is spent by artists and engineers modeling user interactions with virtual agents with which the user acts directly. Virtual crowds, however, form an important component of virtual worlds. It would be unfeasible to author scripted behaviors and interactions for individual members of a virtual crowd. It is typical to rely on systems that allow for autonomous navigation and behavior. We propose some new algorithms and approaches to enhance the plausibility of crowd simulations.

A key component of autonomous human behavior is how they avoid collisions. Many popularly adopted collision avoidance models take as absolute that motion is non-holonomic, or that velocity is expressed only in a forward direction, explicitly ignoring lateral velocities. This does not fully describe how humans actually avoid collisions, how-
ever. We propose a model that incorporates holonomic collision avoidance strategies, (i.e. sidestepping). We describe our model, built from measures and insights gleaned experimentally, that adds holonomic behaviors to the array of collision avoidance strategies that a virtual human can employ. From this research, we learned that holonomic

behavior is largely restricted to complex scenarios where time to collision is short. The most common real-world example, where these types of scenarios happen with regularity is navigating in a dense crowd. We first investigated crowd density from a perceptual perspective and found that spectators’ are quite sensitive to changes in crowd density even at high levels of density. Therefore, in designing a collision avoidance model, care
must be taken to ensure navigation plausibility even at high density. With this insight in mind, we investigated, through the analysis of captured pedestrian data, the degree to which density plays a role in decisions made due to agents perception of density and extrapolate a synthetic vision model capable of conforming to our findings.

Literature on the modeling and simulation of complex adaptive systems (cas) has primarily advanced vertically in different scientific domains with scientists developing a variety of domain-specific approaches and applications. However, while cas researchers are inherently interested in an interdisciplinary comparison of models, to the best of our knowledge, there is currently no single unified framework for facilitating the development, comparison, communication and validation of models across different scientific domains. In this thesis, we propose first steps towards such a unified framework using a combination of agent-based and complex network-based modeling approaches and guidelines formulated in the form of a set of four levels of usage, which allow multidisciplinary researchers to adopt a suitable framework level on the basis of available data types, their research study objectives and expected outcomes, thus allowing them to better plan and conduct their respective research case studies. Firstly, the complex network modeling level of the proposed framework entails the development of appropriate complex network models for the case where interaction data of cas components is available, with the aim of detecting emergent patterns in the cas under study. The exploratory agent-based modeling level of the proposed framework allows for the development of proof-of-concept models for the cas system, primarily for purposes of exploring feasibility of further research. Descriptive agent-based modeling level of the proposed framework allows for the use of a formal step-by-step approach for developing agent-based models coupled with a quantitative complex network and pseudocode-based specification of the model, which will, in turn, facilitate interdisciplinary cas model comparison and knowledge transfer. Finally, the validated agent-based modeling level of the proposed framework is concerned with the building of in-simulation verification and validation of agent-based models using a proposed Virtual Overlay Multiagent System approach for use in a systematic team-oriented approach to developing models. The proposed framework is evaluated and validated using seven detailed case study examples selected from various scientific domains including ecology, social sciences and a range of complex adaptive communication networks. The successful case studies demonstrate the potential of the framework in appealing to multidisciplinary researchers as a methodological approach to the modeling and simulation of cas by facilitating effective communication and knowledge transfer across scientific disciplines without the requirement of extensive learning curves.

Motion planning for multiple entities or a crowd is a challenging problem in today's virtual environments. We describe in this paper a system designed to simulate pedestrian behaviour in crowds in real time, concentrating particularly on collision avoidance. On-line planning is also referred to as the navigation problem. Additional difficulties in approaching navigation problem are that some environments are dynamic. In our model we adopted a popular methodology in computer games, namely A * algorithm to find the first itinerary of each entity. The idea behind A * is to look for the shortest possible routes to the destination, not through exploring exhaustively all possible combinations, but utilizing all possible directions at any given point. In order to deal with collision avoidance problems, priority rules are given to some entities as well as some social behaviour. These rules solved the problem of disorder in the crowd movement.

Work on levels of detail for human simulation has occurred mainly on a geometrical level, either by reducing the numbers of polygons representing a virtual human, or replacing them with a two-dimensional imposter. Approaches that reduce the complexity of motions generated have also been proposed. In this paper, we describe ongoing development of a framework for Adaptive Level Of Detail for Human Animation (ALOHA), which incorporates levels of detail for not only geometry and motion, but also includes a complexity gradient for natural behaviour, both conversational and social.

This paper situates contemporary social scientific studies of crowd events and crowd behaviour in their historical and ideological context. The original ‘crowd science’ developed from definitions of ‘social problems’ that emerged in the late nineteenth century – in particular the concerns among the French
establishment about the threat of the ‘mass’ to ‘civilization’. This, and the surrounding intellectual context, encouraged the development of theoretical models of the crowd characterized by forms of reductionism and irrationalism. Early accounts of ‘mass panic’ similarly suggested that collective behaviour was irrational because it was governed by primitive bio-psychological processes. After describing these early approaches to the crowd, the paper outlines how changes in the late twentieth century, whereby those writing about the crowd were no longer necessarily ‘outside’ crowd events, have coincided with the development of accounts of the crowd which draw upon contemporary social scientific concepts (such as social norms, social identities, and cognition) and which assume that
crowds are not alien to meaningful social and political participation, but integral to it.

Recent advances in crowd simulation techniques have led to realistic agent and group behavior through elaborate behavioral models, complex motion planning algorithms and impressive physics systems. As many crowd simulation solutions typically target only specific types of environment and scenario, a variety of special-purpose methods and systems has emerged that are hard to re-configure and re-use in other contexts. Solving this situation demands a higher-level approach that takes re-use and configuration of crowds as a priority, for adequate application in a broad variety of scenarios, virtual environments and interaction with the entities present in that environment. In this article we propose semantic crowds, a novel approach that allows one to re-use the same crowds for virtually any environment, and have them use the objects available in it in a meaningful manner, without any modification. To have the agents autonomously interact within any virtual world, we minimize in them the information relative to what objects do and how to use them. Instead, that information is stored in the objects themselves, which the agents can then query, based on what they plausibly want to achieve. To facilitate creating such crowds, we developed an interactive crowd editor that provides high-level editing parameters for defining crowd templates. We illustrate the flexibility of semantic crowds by means of two cases, in which we let the same crowd populate quite differently configured airport terminal environments. These examples also highlight that this modular approach easily combines with your custom implementations of agent behavior model and/or motion planner. c 2012 Nick Kraayenbrink, Jassin Kessing, Tim Tutenel, Gerwin de Haan, Fernando Marson, Soraia R Musse and Rafael Bidarra. Published by Elsevier B.V. Selection and/or peer-review under responsibility of the scientific programme committee of VS-Games 2012.

Creating convincing inhabited virtual environments not only requires suitable modelling, but it also relies on sound evaluation methodologies. In this paper, we provide an overview of our preliminary work towards creating and evaluating inhabited, procedurally-generated, virtual cities. Our methodology involves the use of parameterised procedural generation models to provide a large variety of stimuli for supporting psychophysical evaluations of the human perception of agent behaviour in varying urban configurations. Of significance here is the context in which behaviour is perceived, its relationship with the mental models of observers and links to their impressions of realism. The research is envisaged to feed back into improving the urban modelling process while uncovering information about human mental models of urban environments. It is applicable to domains where the perceived realism of virtual crowds in urban environments is of importance, for example, in computer entertainment applications, serious games and cultural heritage recreations, with more general links envisaged to urban design and the psychology of human perception.

As our cities become denser and host larger gathering events, the need for scientific and computational approaches to crowd management increases. Today, our cities must cater to activities and places that involve massive crowds such as the Olympics, large transportation terminals and mega entertainment and shopping centers. The planning challenges for mega events and activities led urban planners to embark on new studies that offer entirely new design approaches for crowd management. This article uses the Hajj project as a case study to illustrate these new approaches. By employing a nontechnical discourse, this article explains software applications for crowd management in three areas: (i) diagnosing problems, (ii) testing designs and (iii) setting operational plans. Collectively, these software tools assisted in creating a new design that facilitated a safe Hajj environment in recent years. The article also discusses the significance of employing on-the-ground assistance to ensure successful planning and design.

Stadiums constitute distinctive characteristics taking its source from several factors such as influence of crowd size, crowd motion and slenderness of the structure. Although many of the existing codes and guidance are being applied during the design stage of these structures, the efficiency of those become questionable especially under dynamic loading. The investigation of the literature clearly states that the real outcomes of this problem need further understanding. This can only be achieved by going deeply into the critical matters such as generating accurate load models and expanding it to lively crowds, using the correct methodology to identify human structure interaction and operational effects of crowd motion on the dynamic properties. This study intends to give a brief explanation about the problems of this phenomenon, addressing the remedies that have been tried so far and giving a roadmap of a continuous research project for this purpose.

Digital representations of the urban environment have constantly increased their complexity: starting from fixed chunks of 2D segment depicting the building base to complex data-sets comprising several layer of information such as multi-resolution GIS data combined with on field 3D data acquisition. Cities in particular and urban development in general emerge from the bottom up, so crowd is an essential part of the city environment but it is often absent from most of the interactive system used to present urban data and landscapes. This paper presents a modular, real-time system based on the open-source framework OpenSceneGraph, providing a realistic and efficient 3D visualization in real-time of complex animated pedestrians within large urban environments, along with tools to visualize, explore and study macroscopic and emerging properties. The system allows to represent large crowd simulations or automatized tracking of real pedestrians streamed from external applications: the component-based design aims to provide efficient workflow for a multi-disciplinary team, including 3D modelers, urban planners, computer scientists, experts of crowd dynamics and other professionals. To evaluate quality, performance and interaction, the system was applied to the case study of “T-Days” in Bologna historical center, using preexisting 3D open-data assets: some results in terms of performance and workflow among different professionals will be presented.

In motion picture movies, large crowds of computer-generated characters are usually included to produce battle scenes of epic proportions. In video games, it is common to find crowds that conform armies controlled by users (or AI) in real-time strategy games, or crowds made of non-player characters (e.g., groups of spectators in a stadium). In virtual environments, it is common to find crowd simulations that interact with other characters and with their surrounding environment.

Building evacuation simulation provides designers with an efficient way of testing the safety of a building before construction. A significant number of models have been developed in a variety of disciplines (computer graphics, robotics, evacuation dynamics, etc.). This paper presents a review of crowd simulation models and selected commercial software tools for high rise building evacuation simulation. The commercial tools selected (STEPS and EXODUS) are grid-based simulations, which allow for efficient implementation but introduce artifacts in the final results. This paper focuses on describing the main challenges and limitation of these tools, in addition to explaining the importance of incorporating human psychological and physiological factors into the models. The paper concludes with an overview of fundamentals that should be applied to simulate human movement closer to real movements of people, where interaction between bodies emerges and flow rates, densities, and speeds become the result of those interactions instead of some predefined value.

This paper highlights the growing need for a realistic crowd simulation in the design of large venues such as concert halls and stadia. A discrete element method (DEM) technique for modelling crowd dynamics has been developed that represents each person within the model as 3 overlapping circles, a position, orientation and velocity in 2D. Contact forces between elements are included in the model as well as psychological forces, motive forces and moments. The motion of each person is then modelled in a Newtonian manner with a numerical integration time-stepping scheme. The model has been shown previously to work well in predicting egress. In this paper the predicted model behaviour is compared to actual video footage shot at various locations around University Park Campus, Nottingham. It did not match well to the video footage when people are moving towards each other, as in cases of contra-flow on a walkway. In order to improve the model, a general algorithm for 'avoidance' was included which appeared to make the model significantly more realistic in these cases. The paper also shows areas for further potential development, such as incorporating people into associative groups such as family or friends.

The simulation of human massive crowds play an important role in real-time application such as games and walkthrough system. This kind of applications can provide an immersive feeling of life into the static scene and enhance the reality of the system. In recent years, there are many significant research and techniques have been developed, mainly focus on the entertainment industry for both real-time and non-real time rendering. This paper will give an overview on crowd behavior in real-time crowd simulation. The work will also cover numerous crowd modeling and rendering techniques.

Crowds of noncombatants play a large and increasingly recognized role in modern military operations and often create substantial difficulties for the combatant forces involved. However, realistic models of crowds are essentially absent from current military simulations. To address this problem, the authors are developing a crowd simulation capable of generating crowds of noncombatant civilians that exhibit a variety of realistic individual and group behaviors at differing levels of fidelity. The crowd simulation is interoperable with existing military simulations using a standard, distributed simulation architecture. Commercial game technology is used in the crowd simulation to model both urban terrain and the physical behaviors of the human characters that make up the crowd. The objective of this article is to present the design and development process of a simulation that integrates commercially available game technology with current military simulations to generate realistic and believable crowd behavior.

In the year 1999 the world population reached 6 billion, doubling the previous census estimate of 1960. Recently, the United States Census Bureau issued a revised forecast for world population showing a projected growth to 9.4 billion by 2050 (US Census Bureau, http://www.census.gov/ipc/www/worldpop.html). Different research disci- plines have studied the crowd phenomenon and its dynamics from a social, psychological and computational standpoint respectively. This paper presents a survey on crowd analysis methods employed in computer vision research and discusses perspectives from other research disciplines and how they can contribute to the computer vision approach.

Object tracking typically relies on a dynamic model to predict the object's location from its past trajectory. In crowded scenarios a strong dynamic model is particularly important, because more accurate predictions allow for smaller search regions, which greatly simplifies data association. Traditional dynamic models predict the location for each target solely based on its own history, without taking into account the remaining scene objects. Collisions are resolved only when they happen. Such an approach ignores important aspects of human behavior: people are driven by their future destination, take into account their environment, anticipate collisions, and adjust their trajectories at an early stage in order to avoid them. In this work, we introduce a model of dynamic social behavior, inspired by models developed for crowd simulation. The model is trained with videos recorded from birds-eye view at busy locations, and applied as a motion model for multi-people tracking from a vehicle-mounted camera. Experiments on real sequences show that accounting for social interactions and scene knowledge improves tracking performance, especially during occlusions.

We present a new algorithm for simulating large-scale crowds at interactive rates based on the Principle of Least Effort. Our approach uses an optimization method to compute a biomechanically energy-efficient, collision-free trajectory that minimizes the amount of effort for each heterogeneous agent in a large crowd. Moreover, the algorithm can automatically generate many emergent phenomena such as lane formation, crowd compression, edge and wake effects ant others. We compare the results from our simulations to data collected from prior studies in pedestrian and crowd dynamics, and provide visual comparisons with real-world video. In practice, our approach can interactively simulate large crowds with thousands of agents on a desktop PC and naturally generates a diverse set of emergent behaviors.

There are many architectural design parameters for public transport stations which include urban and station level studies. Each station must be designed in accordance with the basic passenger requirements such as accessibility, safety, comfort, satisfaction and etc. Circulation spaces must be formed and sized to meet the minimum movement needs of passengers. For an underground station; main entrance region, position of gates, location and number of turnstiles, escalators, stairs, ramps, passageways, intermediate concourses and platforms must be arranged to minimize walking distances and to prevent congestion. In this study, circulation of passengers is simulated in a quantitatively verifiable manner, taking into account how individuals interact with each other and with the physical obstacles in their environment in a metro station. Virtual experiments are performed to see the continuity and density of pedestrian flow at different levels of Haram Area East Metro Station of the first...

Modeling and simulation is useful for analyzing the employment of non-lethal weapons (NLW) in military engagements and Operations Other Than War (OOTW).  A government-industry cooperative effort modified and enhanced a version of the Modular Semi-Automated Forces (ModSAF) simulation used in the STOW-97 exercises to include non-combatant crowd members with reactive behaviors to battlefield events.  In addition to the ModSAF modifications, the project demonstrates the utility and feasibility of integrating an external simulation tool such as Micro Saint into ModSAF.  In our research, we used Micro Saint, a discrete event simulation tool, to rapidly develop human reactive behavior models.  This paper presents a prototype interactive simulation integrating ModSAF and Micro Saint to support simulation-based analyses of the operational impacts of employing non-lethal and lethal weapons in differing contexts.

Crowd Simulation and Visualization are an important aspect of many applications such as Movies, Games and Virtual Reality simulations. The advantage with crowd rendering in movies is that the entire rendering process can be done off-line. And hence ...

As a collective and highly dynamic social group, human crowd is a fascinating phenomenon which has been constantly concerned by experts from various areas. Recently, computer-based modeling and simulation technologies have emerged to support investigation of the dynamics of crowds, such as a crowd's behaviors under normal and emergent situations. This paper assesses the major existing technologies for crowd modeling and simulation. We first propose a two-dimensional categorization mechanism to classify existing work depending on the size of crowds and the timescale of the crowd phenomena of interest. Four evaluation criteria have also been introduced to evaluate existing crowd simulation systems from the point of view of both a modeler and an end-user. We have discussed some influential existing work in crowd modeling and simulation regarding their major features, performance as well as the technologies used in these work. We have also discussed some open problems in the area. This paper will provide the researchers with useful information and insights on the state-of-the-art of the technologies in crowd modeling and simulation as well as future research directions.

Crowdsourcing is rapidly evolving and applied in situations where ideas, labour, opinion or expertise of large groups of people are used. Crowdsourcing is now used in various policy-making initiatives; however, this use has usually focused on open collaboration platforms and specific stages of the policy process, such as agenda-setting and policy evaluations. Other forms of crowdsourcing have been neglected in policy-making, with a few exceptions. This article examines crowdsourcing as a tool for policy-making, and explores the nuances of the technology and its use and implications for different stages of the policy process. The article addresses questions surrounding the role of crowdsourcing and whether it can be considered as a policy tool or as a technological enabler and investigates the current trends and future directions of crowdsourcing.

This paper presents an overview of crowd simulation models, their limitations, and an alternative agentbased approch. First we introduce several methods and then we focus on two widely used and validated simulation tools that use grid-based models. We discus the artifacts that these models introduce regarding the way they treat the space and the implication that this has in the movement of the agents during the simulation. We also describe the limitations that current commercial software tools have in terms of simulating human psychology and physiology. The paper discusses an agent-based alternative approach developed to overcome these limitations. The model allows for the simulation of human movement that can provide results more closely describing behavior of real people during an emergency situation. Flow rates, densities and speeds emerge in our model from the physical interactions between people instead of being predefined.

This paper presents solutions for one requirement of autonomous characters in animation and games: the ability to navigate around their world in a life-like and improvisational manner. These “steering behaviors” are largely independent of the particulars of the character’s means of locomotion. Combinations of steering behaviors can be used to achieve higher level goals (For example: get from here to there while avoiding obstacles, follow this corridor, join that group of characters...) This paper divides motion behavior into three levels. It will focus on the middle level of steering behaviors, briefly describe the lower level of locomotion, and touch lightly on the higher level of goal setting and strategy.

M any applications can benefit from animated virtual crowds. These applications include site planning, education, entertainment, training, and human factors analysis for building evacuation, or other scenarios where masses of people gather such as sporting events, transportation centers, and concerts.