3,132 research outputs found
Supplemental Material, Online_Appendix_ - Random Deviations Improve Micro–Macro Predictions: An Empirical Test
No full text Supplemental Material, Online_Appendix_ for Random Deviations Improve Micro–Macro
Predictions: An Empirical Test by Michael Mäs and Dirk Helbing in Sociological Methods
& Research </p
Sensitivity analysis of permeability parameters for flows on Barcelona networks
No full textWe consider the problem of optimizing vehicular traffic flows on
an urban network of Barcelona type, i.e. square network with
streets of not equal length. In particular, we describe the effects
of variation of permeability parameters, that indicate the amount
of flow allowed to enter a junction from incoming roads.
On each road, a model suggested by Helbing et al. (2007) [11]
is considered: free and congested regimes are distinguished,
characterized by an arrival flow and a departure flow, the latter
depending on a permeability parameter. Moreover we provide a
rigorous derivation of the model from fluid dynamic ones, using
recent results of Bretti et al. (2006) [3]. For solving the dynamics
at nodes of the network, a Riemann solver maximizing the through
flux is used, see Coclite et al. (2005) [4] and Helbing et al.
(2007) [11].
The network dynamics gives rise to complicate equations, where
the evolution of fluxes at a single node may involve time-delayed
terms from all other nodes. Thus we propose an alternative
hybrid approach, introducing additional logic variables. Finally we
compute the effects of variations on permeability parameters over
the hybrid dynamics and test the obtained results via simulations
Origin detecion durin food-borne disease outbreaks - a case study of the 2011 EHEC/HUS outbreak in Germany
Get PDFThe key challenge during food-borne disease outbreaks, e.g. the 2011 EHEC/HUS outbreak in Germany, is the design of efficient mitigation strategies based on a timely identification of the outbreak’s spatial origin. Standard public health procedures typically use case-control studies and tracings along food shipping chains. These methods are time-consuming and suffer from biased data collected slowly in patient interviews. Here we apply a recently developed, network-theoretical method to identify the spatial origin of food-borne disease outbreaks. Thereby, the network captures the transportation routes of contaminated foods. The technique only requires spatial information on case reports regularly collected by public health institutions and a model for the underlying food distribution network. The approach is based on the idea of replacing the conventional geographic distance with an effective distance that is derived from the topological structure of the underlying food distribution network. We show that this approach can efficiently identify most probable epicenters of food-borne disease outbreaks. We assess and discuss the method in the context of the 2011 EHEC epidemic. Based on plausible assumptions on the structure of the national food distribution network, the approach can correctly localize the origin of the 2011 German EHEC/HUS outbreak
"Digital Religion(s)" stellte sich vor
No full textDer Forschungsschwerpunkt «Digital Religion(s)» der Universität Zürich ist seit 2021 aktiv. Wegen der Corona-Pandemie konnte noch kein Kick-Off-Anlass durchgeführt werden. Dieser fand nun am 1. April 2022 in Zürich statt.
Im Beitrag sind Personen aus folgenden Fachgebieten zu hören:
Prof. Dr. Thomas Schlag (Theologie, Leiter Zentrum für Kirchenentwicklung)
PD Dr. Sabrina Müller (Theologie, Geschäftsleiterin des Universitären Forschungsschwerpunktes (UFSP) Digital Religion(s))
Ramazan Özgü (Rechtswissenschaft)
Dr. Lisa Schwaiger (Soziologie)
Prof. Dr. Dirk Helbing (Physik, Soziologie)
Evelyne Baumberger (Theologie und Bloggerin
Socio-inspired ICT: Towards a socially grounded society-ICT symbiosis
Get PDFModern ICT (Information and Communication Technology) has developed a vision where the “computer” is no longer associated with the concept of a single device or a network of devices, but rather the entirety of situated services originating in a digital world, which are perceived through the physical world. It is observed that services with explicit user input and output are becoming to be replaced by a computing landscape sensing the physical world via a huge variety of sensors, and controlling it via a plethora of actuators. The nature and appearance of computing devices is changing to be hidden in the fabric of everyday life, invisibly networked, and omnipresent, with applications greatly being based on the notions of context and knowledge. Interaction with such globe spanning, modern ICT systems will presumably be more implicit, at the periphery of human attention, rather than explicit, i.e. at the focus of human attention.Socio-inspired ICT assumes that future, globe scale ICT systems should be viewed as social systems. Such a view challenges research to identify and formalize the principles of interaction and adaptation in social systems, so as to be able to ground future ICT systems on those principles. This position paper therefore is concerned with the intersection of social behaviour and modern ICT, creating or recreating social conventions and social contexts through the use of pervasive, globe-spanning, omnipresent and participative ICTValues and TechnologyTechnology, Policy and Managemen
Bankruptcy cascades in interbank markets.
No full textWe study a credit network and, in particular, an interbank system with an agent-based model. To understand the relationship between business cycles and cascades of bankruptcies, we model a three-sector economy with goods, credit and interbank market. In the interbank market, the participating banks share the risk of bad debits, which may potentially spread a bank's liquidity problems through the network of banks. Our agent-based model sheds light on the correlation between bankruptcy cascades and the endogenous economic cycle of booms and recessions. It also demonstrates the serious trade-off between, on the one hand, reducing risks of individual banks by sharing them and, on the other hand, creating systemic risks through credit-related interlinkages of banks. As a result of our study, the dynamics underlying the meltdown of financial markets in 2008 becomes much better understandable
Cooperation, Norms, and Revolutions: A Unified Game-Theoretical Approach
No full textBackground: Cooperation is of utmost importance to society as a whole, but is often challenged by individual self-interests. While game theory has studied this problem extensively, there is little work on interactions within and across groups with different preferences or beliefs. Yet, people from different social or cultural backgrounds often meet and interact. This can yield conflict, since behavior that is considered cooperative by one population might be perceived as non-cooperative from the viewpoint of another.Methodology and Principal Findings: To understand the dynamics and outcome of the competitive interactions within and between groups, we study game-dynamical replicator equations for multiple populations with incompatible interests and different power (be this due to different population sizes, material resources, social capital, or other factors). These equations allow us to address various important questions: For example, can cooperation in the prisoner's dilemma be promoted, when two interacting groups have different preferences? Under what conditions can costly punishment, or other mechanisms, foster the evolution of norms? When does cooperation fail, leading to antagonistic behavior, conflict, or even revolutions? And what incentives are needed to reach peaceful agreements between groups with conflicting interests?Conclusions and Significance: Our detailed quantitative analysis reveals a large variety of interesting results, which are relevant for society, law and economics, and have implications for the evolution of language and culture as well
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