Bottom-up insight into crowd dynamics

A new study proposes a method for quantitatively analyzing the relative value of models for crowd dynamics prediction

2014-02-07

(Press-News.org) Stampedes unfortunately occur on too regular a basis. Previously, physicists developed numerous models of crowd evacuation dynamics. Their analyses focused on disasters such as the yearly Muslim Hajj or of the Love Parade disaster in Germany in 2010. Unfortunately, the casualties at these events may have been linked to the limitations of the crowd dynamics models used at the time. Now, a new study outlines a procedure for quantitatively comparing different crowd models, which also helps to compare these models with real-world data. In a paper published in EPJ B, Vaisagh Viswanathan, a PhD student from Nanyang Technological University in Singapore, and colleagues have demonstrated that these crowd evacuation dynamics models are a viable decision-making tool in safety preparation and planning concerning real-world human crowds.

The trouble with such models, however, is that they rely on real-world data of crowds that is limited and incomplete. Often only top-down, macroscopic scale measurements of data such as flow, density, and average speed are used. It is not clear whether these metrics can validate the modelled dynamics at the individual level.

Instead of using data that is so difficult to source, Viswanthan and colleagues adopted a quantitative study comparing the simulated congestion flow rates, among other things, of three so-called bottom-up models. These focus on the individual behaviour of school children evacuating their classroom during the May 2008 Sichuan Earthquake.

They found that a model referred to as the social force model — based on the idea that pedestrians move in response to fictitious attractive or repulsive social forces — best matches the real-world data showing how pupils exit their classrooms.

They also identified a new macroscopic metric, 'the zoned evacuation time', as the one observable parameter that can best discriminate between these models, and also between models and real-world data.

INFORMATION: Reference:

V. Viswanthan et al. (2014), Quantitative Comparison Between Crowd Models for Evacuation Planning and Evaluation, European Physical Journal B, DOI 10.1140/epjb/e2014-40699-x

For more information visit: http://www.epj.org

The full-text article is available to journalists on request.

ELSE PRESS RELEASES FROM THIS DATE:

Researchers use genetic signals affecting lipid levels to probe heart disease risk

2014-02-07

New genetic evidence strengthens the case that one well-known type of cholesterol is a likely suspect in causing heart disease, but also casts further doubt on the causal role played by another type. The findings may guide the search for improved treatments for heart disease. Most of us have heard of "good cholesterol" and "bad cholesterol" coursing through our bloodstream. In the conventional health wisdom of the past 30 years, having more of the "good" variety (high-density lipoprotein, or HDL) lowers your risk of heart disease, while more of the bad one (low-density ...

Shape-sifting: NIST categorizes bio scaffolds by characteristic cell shapes

2014-02-07

Getting in the right shape might be just as important in a biology lab as a gym. Shape is thought to play an important role in the effectiveness of cells grown to repair or replace damaged tissue in the body. To help design new structures that enable cells to "shape up," researchers at the National Institute of Standards and Technology (NIST) have come up with a way to measure, and more importantly, classify, the shapes cells tend to take in different environments.* With the notable exception of Flat Stanley, we all live, and are shaped by, a 3-dimensional world. Biologists ...

Computer models help decode cells that sense light without seeing

2014-02-07

Researchers have found that the melanopsin pigment in the eye is potentially more sensitive to light than its more famous counterpart, rhodopsin, the pigment that allows for night vision. For more than two years, the staff of the Laboratory for Computational Photochemistry and Photobiology (LCPP) at Ohio's Bowling Green State University (BGSU), have been investigating melanopsin, a retina pigment capable of sensing light changes in the environment, informing the nervous system and synchronizing it with the day/night rhythm. Most of the study's complex computations were ...

Variability of contact precaution policies in US emergency departments

2014-02-07

In a study published in Infection Control and Hospital Epidemiology on February 7, 2014, Daniel J. Pallin, MD, MPH and Jeremiah D. Schuur, MD, MS, surveyed a random sample of US emergency departments (EDs) and found substantial variation in the adoption of policies relating to contact precautions. While most EDs have policies relating to contact precautions when specific organisms are suspected, a minority have such policies for the symptoms often caused by those organisms. This indicated that institutional policies do not mirror consensus recommendations by the CDC, ...

Panel issues report on gray wolf science

2014-02-07

(Santa Barbara, Calif.) — As the Endangered Species Act (ESA) celebrated its 40th anniversary at the end of 2013, its administrative agency, the U.S. Fish and Wildlife Service (USFWS), was mired in controversy. At issue was a proposal to remove the gray wolf (Canis lupus) from the List of Endangered and Threatened Wildlife and add the Mexican gray wolf (Canis lupus baileyi). As a result, the USFWS sought an independent peer review of the science behind the proposed rule to delist the gray wolf species. The agency commissioned UC Santa Barbara's National Center for Ecological ...

Study shows drop in crime rates are less where Wal-Mart builds

2014-02-07

Communities across the United States experienced an unprecedented decline in crime in the 1990s. But for counties where Wal-Mart built stores, the decline wasn't nearly as dramatic. "The crime decline was stunted in counties where Wal-Mart expanded in the 1990s," says Scott Wolfe, assistant professor of criminology and criminal justice at the University of South Carolina and lead author of a new study. "If the corporation built a new store, there were 17 additional property crimes and 2 additional violent crimes for every 10,000 persons in a county." The study, titled ...

Researchers at UGent and VIB, discovered potential novel treatment against septic shock

2014-02-07

Septic shock is caused by excessive and systemic reaction of the entire body against infectious agents, in most cases of bacterial origin. The number of deaths by septic shock in intensive care units is very high and is still increasing, despite numerous large scale clinical trials. Scientists of VIB and UGent, supervised by Peter Vandenabeele, demonstrated in a mouse study that a potential novel treatment for sepsis may consist of the simultaneous neutralization of two harmful cytokines in the blood circulation, namely interleukin-1 and interleukin-18. In the VIB research ...

Dating is refined for the Atapuerca site where Homo antecessor appeared

2014-02-07

One of the issues of the Atapuerca sites that generates the most scientific debate is the dating of the strata where the fossils are found. Therefore, researchers at the Spanish National Research Centre for Human Evolution, among others, strive to settle the dates. A study published by the 'Journal of Archaeological Science' has clarified that the sediment of Gran Dolina, where the first remains of Homo antecessor were discovered in 1994, is 900,000 years old. The findings at the Lower Palaeolithic cave site of Gran Dolina, in the Sierra de Atapuerca mountain range (Burgos), ...

Protein structure: Peering into the transit pore

2014-02-07

The lipid-rich membranes of cells are largely impermeable to proteins, but evolution has provided a way through – in the form of transmembrane tunnels. A new study shows in unmatched detail what happens as proteins pass through such a pore. Every cell is surrounded by a surface membrane and contains internal compartments bounded by membranes. Almost one-third of all proteins synthesized in cells must pass through these membranes or be incorporated into them in order to fulfil their functions. However, the fat-rich nature of membranes makes it impossible for most proteins ...

Beta blockers and perioperative care: EHJ editorial addresses controversy

2014-02-07

Zurich, 7 February 2014. Since the end of 2011 when the scientific work of Professor Don Poldermans was first scrutinized there has been controversy in the medical world about the use of beta blockers in perioperative care. The recent publication - and retraction for proper peer reviewing and revision - in the European Heart Journal (EHJ) of a paper by Professors Cole and Francis from Imperial College, questioning whether beta blockers in perioperative care could lead to a mortality increase brought the topic back into the public eye. The EHJ has published an editorial ...

LAST 30 PRESS RELEASES:

Association of waist circumference with all-cause and cardiovascular mortalities in diabetes from the National Health and Nutrition Examination Survey 2003–2018