Basics of Modelling the Pedestrian Flow

For the modelling of pedestrian dynamics we treat persons as self-driven objects moving in a continuous space. On the basis of a modified social force model we qualitatively analyze the influence of various approaches for the interaction between the pedestrians on the resulting velocity-density relation. To focus on the role of the required space and remote force we choose a one-dimensional model for this investigation. For those densities, where in two dimensions also passing is no longer possible and the mean value of the velocity depends primarily on the interaction, we obtain the following result: If the model increases the required space of a person with increasing current velocity, the reproduction of the typical form of the fundamental diagram is possible. Furthermore we demonstrate the influence of the remote force on the velocity-density relation.Comment: 9 pages, 3 figures, Changes: Parameter e=0.51 corrected to e =0.07 (see Fig. 2) and prep. for subm. to Phys. Rev.

Network-Induced Oscillatory Behavior in Material Flow Networks

Network theory is rapidly changing our understanding of complex systems, but the relevance of topological features for the dynamic behavior of metabolic networks, food webs, production systems, information networks, or cascade failures of power grids remains to be explored. Based on a simple model of supply networks, we offer an interpretation of instabilities and oscillations observed in biological, ecological, economic, and engineering systems. We find that most supply networks display damped oscillations, even when their units - and linear chains of these units - behave in a non-oscillatory way. Moreover, networks of damped oscillators tend to produce growing oscillations. This surprising behavior offers, for example, a new interpretation of business cycles and of oscillating or pulsating processes. The network structure of material flows itself turns out to be a source of instability, and cyclical variations are an inherent feature of decentralized adjustments.Comment: For related work see http://www.helbing.or

Experimental Analysis of Latent Heat Storages integrated into a Liquid Cooling System for the Cooling of Power Electronics

The progressive electrification in automotive and aircraft industry results in increasing power densities and waste heat of power electronics. Due to higher power densities air cooling systems are substituted by more effective but in many cases heavier liquid cooling systems. Since the weight of cooling systems is a crucial aspect during the design process of vehicles, the dimensions of the cooling systems should be minimized. The dynamics of power electronics’ waste heat implies often short periods of high waste heat, so-called peaks. Cooling systems are usually designed for maximum waste heat.  This leads to an oversized cooling system for a wide range of operating points. Latent Heat Storages (LHS) compensates peaks and enables a downgrade of the cooling system, which in turn reduces the cooling system weight. The integration of a Composite Latent Heat Storage (CLHS) into a liquid cooling system is investigated experimentally at Hamburg University of Technology. The main objective is to analyze the implementation of a LHS as a buffer storage under different boundary conditions. The test rig is designed for a maximum waste heat of 500 W, resulting in a maximum heat flux density of 20.8 W/cm². The heat is applied by three cartridge heaters embedded into an aluminium body representing a power electronics module. The latent heat storage uses paraffin as Phase Change Materials (PCM). On the one hand paraffins allow a light-weight storage, but on the other hand they have a very low thermal conductivity, therefore a finned aluminum structure is used to improve the transport of the waste heat into the PCM. The power electronics dummy is fixed between the latent heat storage and a cold plate. The temperature is measured on both contact surfaces of the LHS. The cooling cycle is a one-phase cooling cycle with a heat exchanger as heat sink, a tank, a cold plate and a pump, which provides a maximum mass flow rate of 1200 kg/h. The coolant is Propylene-Glycol-Water (PGW) in a mixture of 60/40. The dynamics of the waste heat are given by a laboratory power supply. The paper presents the results of tests showing the influence of different waste heat load progressions including the melting and the solidification. All tests are performed for a CLHS and a Sensible Heat Storage (SHS) made of aluminium. The focus is on the buffering of the thermal energy in order to reduce the required mass flow rate and in consequence the weight

How Natural Selection Can Create Both Self- and Other-Regarding Preferences, and Networked Minds

Biological competition is widely believed to result in the evolution of selfish preferences. The related concept of the `homo economicus' is at the core of mainstream economics. However, there is also experimental and empirical evidence for other-regarding preferences. Here we present a theory that explains both, self-regarding and other-regarding preferences. Assuming conditions promoting non-cooperative behaviour, we demonstrate that intergenerational migration determines whether evolutionary competition results in a `homo economicus' (showing self-regarding preferences) or a `homo socialis' (having other-regarding preferences). Our model assumes spatially interacting agents playing prisoner's dilemmas, who inherit a trait determining `friendliness', but mutations tend to undermine it. Reproduction is ruled by fitness-based selection without a cultural modification of reproduction rates. Our model calls for a complementary economic theory for `networked minds' (the `homo socialis') and lays the foundations for an evolutionarily grounded theory of other-regarding agents, explaining individually different utility functions as well as conditional cooperation

Physics, Stability and Dynamics of Supply Networks

We show how to treat supply networks as physical transport problems governed by balance equations and equations for the adaptation of production speeds. Although the non-linear behaviour is different, the linearized set of coupled differential equations is formally related to those of mechanical or electrical oscillator networks. Supply networks possess interesting new features due to their complex topology and directed links. We derive analytical conditions for absolute and convective instabilities. The empirically observed "bull-whip effect" in supply chains is explained as a form of convective instability based on resonance effects. Moreover, it is generalized to arbitrary supply networks. Their related eigenvalues are usually complex, depending on the network structure (even without loops). Therefore, their generic behavior is characterized by oscillations. We also show that regular distribution networks possess two negative eigenvalues only, but perturbations generate a spectrum of complex eigenvalues.Comment: For related work see http://www.helbing.or

Die Zikadenfauna isolierter Schieferkuppen der Medebacher Bucht (Südwestfalen/Nordhessen): (Hemiptera, Auchenorrhyncha)

Im Jahr 2014 wurden auf 30 Schieferkuppen der Medebacher Bucht (Südwestfalen/Nordhessen) systematische Zikadenerfassungen durchgeführt. Insgesamt konnten 102 Arten nachgewiesen werden. Davon sind 31 Arten in der Roten Liste der gefährdeten Zikadenarten Deutschlands einer Gefährdungskategorie zugeordnet. Acht Arten wurden als Trockenrasen-Spezialisten und 60 Arten als typische Grünlandbewohner eingestuft. Besonders hervorzuheben sind die Nachweise von Delphacinus mesomelas, Jassidaeus lugubris, Stictocoris picturatus und Xanthodelphax flaveola. Sie sind alle Indikatoren historisch alter, extensiv genutzter Weidelandschaften. Jassidaeus lugubris und Xanthodelphax flaveola konnten erstmalig für Nordrhein-Westfalen nachgewiesen werden.The Auchenorrhyncha fauna (Hemiptera) of isolated acidic hilltops of the “Medebacher Bucht” (central Germany). – In 2014 we sampled Auchenorrhyncha on 30 acidic grassland sites in the “Medebacher Bucht” (central Germany). In total, we found 102 species. Among these, 31 species are on the Red List of the Auchenorrhyncha of Germany. A total of eight species were classified as xerothermophilous habitat specialists and 60 species as typical grassland species in Germany. Particularly noteworthy are the records of Delphacinus mesomelas, Jassidaeus lugubris, Stictocoris picturatus und Xanthodelphax flaveola. All of them are indicators for ancient traditionally grazed pastures. The records of Jassidaeus lugubris and Xanthodelphax flaveola were new for North North-Rhine-Westphalia

Leitfaden zum Datenschutz in medizinischen Forschungsprojekten

Das Vertrauen von Patienten und Probanden ist eine unverzichtbare Voraussetzung für den Erfolg medizinischer Forschungsprojekte, die ohne die Erhebung, langfristige Speicherung und Analyse von klinischen Daten und Proben nicht durchgeführt werden können. Medizinische Forschung arbeitet heute überwiegend vernetzt in zunehmend größeren Forschungsverbünden. Entsprechend nimmt auch die Bedeutung von Datenschutz und Datensicherheit immer weiter zu. Die TMF hat bereits 2003 erstmals generische Datenschutzkonzepte für medizinische Forschungsverbünde veröffentlicht. Auf dieser Basis konnten zahlreiche Forschungsprojekte ihre Datenschutzkonzepte schneller erarbeiten und abstimmen. Die dabei gewonnenen Erfahrungen sind in die grundlegende Überarbeitung der generischen Konzepte eingeflossen. So trägt das neue Konzept der Vielschichtigkeit medizinischer Forschungsprozesse durch einen modularen Aufbau Rechnung und wurde zudem in einen umfassenden Leitfaden eingebettet

Triage 4.0:On Death Algorithms and Technological Selection. Is Today’s Data- Driven Medical System Still Compatible with the Constitution?

Health data bear great promises for a healthier and happier life, but they also make us vulnerable. Making use of millions or billions of data points, Machine Learning (ML) and Artificial Intelligence (AI) are now creating new benefits. For sure, harvesting Big Data can have great potentials for the health system, too. It can support accurate diagnoses, better treatments and greater cost effectiveness. However, it can also have undesirable implications, often in the sense of undesired side effects, which may in fact be terrible. Examples for this, as discussed in this article, are discrimination, the mechanisation of death, and genetic, social, behavioural or technological selection, which may imply eugenic effects or social Darwinism. As many unintended effects become visible only after years, we still lack sufficient criteria, long-term experience and advanced methods to reliably exclude that things may go terribly wrong. Handing over decision-making, responsibility or control to machines, could be dangerous and irresponsible. It would also be in serious conflict with human rights and our constitution

Burkhardt-Cottingham sum rule and forward spin polarizabilities in Heavy Baryon Chiral Perturbation Theory

We study spin-dependent sum rules for forward virtual Compton scattering(VVCS) off the nucleon in heavy baryon chiral perturbation theory at order $O(p^4)$. We show how these sum rules can be evaluated from low energy expansions (in the virtual photon energy) of the forward VVCS amplitudes. We study in particular the Burkhardt -Cottingham sum rule in HBChPT and higher terms in the low energy expansion, which can be related to the generalized forward spin polarizabilities of the nucleon. The dependence of these observables on the photon virtuality $Q^2$ can be accessed, at small and intermediate $Q^2$ values, from existing and forthcoming data at Jefferson Lab.Comment: 16 pages,4 fig