312 research outputs found
A control theoretic model of driver steering behavior
A quantitative description of driver steering behavior such as a mathematical model is presented. The steering task is divided into two levels: (1) the guidance level involving the perception of the instantaneous and future course of the forcing function provided by the forward view of the road, and the response to it in an anticipatory open-loop control mode; (2) the stabilization level whereby any occuring deviations from the forcing function are compensated for in a closed-loop control mode. This concept of the duality of the driver's steering activity led to a newly developed two-level model of driver steering behavior. Its parameters are identified on the basis of data measured in driving simulator experiments. The parameter estimates of both levels of the model show significant dependence on the experimental situation which can be characterized by variables such as vehicle speed and desired path curvature
A Qualitative Case Study: The Lived Educational Experiences of Former Juvenile Delinquents
The impact of juvenile delinquency on society is an issue of great concern. The impact of delinquent behaviors goes beyond the victim to include the offender, the offender’s family and society as a whole. A review of the existing literature reveals multiple studies, which examine delinquency from a causal perspective. Despite the efforts of researchers a definitive causal link is not readily determined. Ethical concerns centering around a quantitative study on delinquency precludes the discovery of such a causal link. Utilizing a qualitative study approach we may not be able to identify causal relationships; however, this approach provides clear insight into the lived experiences of the individuals being studied and in turn offers us the possibility of understanding what these experiences were and how they possibly impacted the individual. It is through this understanding of the lived experiences that we gain insight. This insight will, hopefully, facilitate the prediction of and the mediation of anti-social juvenile behavior
Remote manipulator dynamic simulation
A simulator to generate the real time visual scenes required to perform man in the loop investigations of remote manipulator application and design concepts for the space shuttle is described. The simulated remote manipulator consists of a computed display system that uses a digital computer, the electronic scene generator, an operator's station, and associated interface hardware. A description of the capabilities of the implemented simulation is presented. The mathematical models and programs developed for the simulation are included
A network-based microfoundation of Granovetter's threshold model for social tipping
Social tipping, where minorities trigger larger populations to engage in
collective action, has been suggested as one key aspect in addressing
contemporary global challenges. Here, we refine Granovetter's widely
acknowledged theoretical threshold model of collective behavior as a numerical
modelling tool for understanding social tipping processes and resolve issues
that so far have hindered such applications. Based on real-world observations
and social movement theory, we group the population into certain or potential
actors, such that -- in contrast to its original formulation -- the model
predicts non-trivial final shares of acting individuals. Then, we use a network
cascade model to explain and analytically derive that previously hypothesized
broad threshold distributions emerge if individuals become active via social
interaction. Thus, through intuitive parameters and low dimensionality our
refined model is adaptable to explain the likelihood of engaging in collective
behavior where social tipping like processes emerge as saddle-node bifurcations
and hysteresis
Meereswirtschaft in Europa : rechtliche und ökonomische Rahmenbedingungen für deutsche Unternehmen.
Meeresnutzung; Meeresboden; Meeresbergbau; Seerecht; Erdgasvorkommen; Fischerei; EU-Staaten; Norwegen; Deutschland;
Investigating the topology of interacting networks - Theory and application to coupled climate subnetworks
Network theory provides various tools for investigating the structural or
functional topology of many complex systems found in nature, technology and
society. Nevertheless, it has recently been realised that a considerable number
of systems of interest should be treated, more appropriately, as interacting
networks or networks of networks. Here we introduce a novel graph-theoretical
framework for studying the interaction structure between subnetworks embedded
within a complex network of networks. This framework allows us to quantify the
structural role of single vertices or whole subnetworks with respect to the
interaction of a pair of subnetworks on local, mesoscopic and global
topological scales.
Climate networks have recently been shown to be a powerful tool for the
analysis of climatological data. Applying the general framework for studying
interacting networks, we introduce coupled climate subnetworks to represent and
investigate the topology of statistical relationships between the fields of
distinct climatological variables. Using coupled climate subnetworks to
investigate the terrestrial atmosphere's three-dimensional geopotential height
field uncovers known as well as interesting novel features of the atmosphere's
vertical stratification and general circulation. Specifically, the new measure
"cross-betweenness" identifies regions which are particularly important for
mediating vertical wind field interactions. The promising results obtained by
following the coupled climate subnetwork approach present a first step towards
an improved understanding of the Earth system and its complex interacting
components from a network perspective
A k-shell decomposition method for weighted networks
We present a generalized method for calculating the k-shell structure of
weighted networks. The method takes into account both the weight and the degree
of a network, in such a way that in the absence of weights we resume the shell
structure obtained by the classic k-shell decomposition. In the presence of
weights, we show that the method is able to partition the network in a more
refined way, without the need of any arbitrary threshold on the weight values.
Furthermore, by simulating spreading processes using the
susceptible-infectious-recovered model in four different weighted real-world
networks, we show that the weighted k-shell decomposition method ranks the
nodes more accurately, by placing nodes with higher spreading potential into
shells closer to the core. In addition, we demonstrate our new method on a real
economic network and show that the core calculated using the weighted k-shell
method is more meaningful from an economic perspective when compared with the
unweighted one.Comment: 17 pages, 6 figure
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Closing the loop: Reconnecting human dynamics to Earth System science
International commitment to the appropriately ambitious Paris climate agreement and the United Nations Sustainable Development Goals in 2015 has pulled into the limelight the urgent need for major scientific progress in understanding and modelling the Anthropocene, the tightly intertwined social-environmental planetary system that humanity now inhabits. The Anthropocene qualitatively differs from previous eras in Earth’s history in three key characteristics: (1) There is planetary-scale human agency. (2) There are social and economic networks of teleconnections spanning the globe. (3) It is dominated by planetary-scale social-ecological feedbacks. Bolting together old concepts and methodologies cannot be an adequate approach to describing this new geological era. Instead, we need a new paradigm in Earth System science that is founded equally on a deep understanding of the physical and biological Earth System – and of the economic, social and cultural forces that are now an intrinsic part of it. It is time to close the loop and bring socially mediated dynamics explicitly into theory, analysis and models that let us study the whole Earth System
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