From individual behaviour to an evaluation of the collective evolution of crowds along footbridges

This paper proposes a crowd dynamic macroscopic model grounded on microscopic phenomenological observations which are upscaled by means of a formal mathematical procedure. The actual applicability of the model to real world problems is tested by considering the pedestrian traffic along footbridges, of interest for Structural and Transportation Engineering. The genuinely macroscopic quantitative description of the crowd flow directly matches the engineering need of bulk results. However, three issues beyond the sole modelling are of primary importance: the pedestrian inflow conditions, the numerical approximation of the equations for non trivial footbridge geometries, and the calibration of the free parameters of the model on the basis of in situ measurements currently available. These issues are discussed and a solution strategy is proposed.Comment: 23 pages, 10 figures in J. Engrg. Math., 201

Deterministic chaos theory and forecasting in Social Sciences. Contribution to the discussion

Forecasting social phenomena may be hampered in many ways. This is because in nature of these phenomena lies strong and multilateral connection with other social phenomena; but not only – also physical and biological (natural) ones. The content of this publication constitutes presentation of chosen problems of forecasting in social sciences. The attention in the article was focused among others on deterministic chaos theory, on the attempt of its implementation to phenomena from the scope (or from borderline) of social sciences: economy, logistics, science about safety etc. Moreover, one of the threads of ponderation was the attempt to consider whether it’s possible to create so-called final theory. The aim of the publication is to signalize possibilities of taking advantage of seemingly exotic for “political scientists” methodology of modeling and explaining phenomena, having its source in exact sciences (in chaos theory) to study social phenomena and processes

Émile Zola’s climate history of the Second Empire

This article looks at Émile Zola’s novel cycle “Les Rougon-Macquart” and argues that it describes its subject, the Second Empire, as a warming climate tending toward climate catastrophe. Zola’s affinity to the notion of climate is shown to be linked to his poetic employment of the concept of ‘milieu,’ inspired by Hippolyte Taine. Close readings of selected passages from the “Rougon-Macquart” are used to work out the climatic difference between ‘the old’ and ‘the new Paris,’ and the process of warming that characterises the Second Empire. Octave Mouret’s department store holds a special place in the article, as it is analysed through what the article suggests calling a ‘meteorotopos’: a location of intensified climatic conditions that accounts for an increased interaction between human and non-human actors. The department store is also one of the many sites in the novel cycle that locally prefigure the ‘global’ climate catastrophe of Paris burning, in which the Second Empire perishes.El artículo hace una lectura del ciclo de novelas “Les Rougon-Macquart” de Émile Zola y sostiene la tesis de que el sujeto al que describe, el Segundo Imperio, puede leerse como un clima en proceso de calentamiento que se dirige hacia una catástrofe medioambiental. La afinidad de Zola con la noción de clima se ve expuesta al conectarla con su uso poetológico del concepto de ‘milieu’, inspirado en Hippolyte Taine. El artículo ofrece una lectura en profundidad de ciertos pasajes de las novelas “Rougon-Macquart” para mostrar las diferencias climáticas entre el “viejo” y el “nuevo París”, y el proceso de calentamiento que caracteriza el Segundo Imperio. El gran almacén de Octave Mouret es analizado, en particular, bajo el concepto de “meteorotopos” propuesto en el artículo: un lugar de condiciones climáticas intensificadas, un lugar de interacción aumentada entre actores humanos y no-humanos. El almacén es uno de varios espacios en el ciclo de novelas en los que ya se señala la catástrofe climática ‘global’ del París en llamas, momento en que se hunde el Segundo Imperio

Statistical fluctuations in pedestrian evacuation times and the effect of social contagion

Mathematical models of pedestrian evacuation and the associated simulation software have become essential tools for the assessment of the safety of public facilities and buildings. While a variety of models are now available, their calibration and test against empirical data are generally restricted to global, averaged quantities, the statistics compiled from the time series of individual escapes (" microscopic " statistics) measured in recent experiments are thus overlooked. In the same spirit, much research has primarily focused on the average global evacuation time, whereas the whole distribution of evacuation times over some set of realizations should matter. In the present paper we propose and discuss the validity of a simple relation between this distribution and the " microscopic " statistics, which is theoretically valid in the absence of correlations. To this purpose, we develop a minimal cellular automaton, with novel features that afford a semi-quantitative reproduction of the experimental " microscopic " statistics. We then introduce a process of social contagion of impatient behavior in the model and show that the simple relation under test may dramatically fail at high contagion strengths, the latter being responsible for the emergence of strong correlations in the system. We conclude with comments on the potential practical relevance for safety science of calculations based on " microscopic " statistics

Should the government provide insurance for catastrophes?

This paper evaluates the need for a government role in insuring natural and man-made catastrophes in the United States. Although insurance markets have been stressed by major natural catastrophes, such as Hurricane Katrina, government involvement in the market for natural catastrophe insurance should be minimized to avoid crowding-out more efficient private market solutions, such as catastrophe bonds. Instead, government should facilitate the development of the private market by reducing regulatory barriers. The National Flood Insurance Program has failed to cover most property owners exposed to floods and is facing severe financial difficulties. The program needs to be drastically revised or replaced by private market alternatives, such as federal "make available" requirements with a federal reinsurance backstop. A federal role may be appropriate to insure against mega-terrorist events. However, any program should be minimally intrusive and carry a positive premium to avoid crowding-out private market alternatives.Insurance, Government

From mindless masses to small groups: Conceptualizing collective behavior in crowd modeling.

Computer simulations are increasingly used to monitor and predict behavior at large crowd events, such as mass gatherings, festivals and evacuations. We critically examine the crowd modeling literature and call for future simulations of crowd behavior to be based more closely on findings from current social psychological research. A systematic review was conducted on the crowd modeling literature (N = 140 articles) to identify the assumptions about crowd behavior that modelers use in their simulations. Articles were coded according to the way in which crowd structure was modeled. It was found that 2 broad types are used: mass approaches and small group approaches. However, neither the mass nor the small group approaches can accurately simulate the large collective behavior that has been found in extensive empirical research on crowd events. We argue that to model crowd behavior realistically, simulations must use methods which allow crowd members to identify with each other, as suggested by self-categorization theory