Thermostating by Deterministic Scattering: Heat and Shear Flow

We apply a recently proposed novel thermostating mechanism to an interacting many-particle system where the bulk particles are moving according to Hamiltonian dynamics. At the boundaries the system is thermalized by deterministic and time-reversible scattering. We show how this scattering mechanism can be related to stochastic boundary conditions. We subsequently simulate nonequilibrium steady states associated to thermal conduction and shear flow for a hard disk fluid. The bulk behavior of the model is studied by comparing the transport coefficients obtained from computer simulations to theoretical results. Furthermore, thermodynamic entropy production and exponential phase-space contraction rates in the stationary nonequilibrium states are calculated showing that in general these quantities do not agree.Comment: 16 pages (revtex) with 9 figures (postscript

Short Term Living Conditions and Long Term Prospects of Immigrant Children in Germany

In Germany the foreign born population is made up of foreigners and so called "ethnic Germans" who migrated from eastern European countries to Germany. While the first group is confronted with problems arising from the typical German concept of ethnicity and citizenship, the latter are entitled to a German passport immediately after crossing the border. About one half of the immigrants who entered Germany since 1984 are ethnic Germans. Thus, any analysis of the living conditions of immigrant children in comparison to native born German children must take into account the heterogeneity of immigrants in Germany as well as the respective institutional settings. Throughout the last decade the financial situation of children in Germany has been marked by increasing problems: in 1997 the population share of children living in households receiving welfare payments was about twice as high as the respective share for the entire population. Poverty head count rates (based on a poverty threshold of 50 percent of median equivalent income) clearly increased over this period from about 10 percent to more than 15 percent in 1996. The central aim of this paper is to analyze differences between native and foreign children within this process. Our comparative analyses are based on the different sub-samples of the German Socio- Economic Panel Study (GSOEP). With respect to non-monetary as well as monetary indicators there are - although the German transfer system is strong - remarkable differences in living conditions between native born German children and those born to immigrants and foreigners. On average we find that children in Germany to have lost out in terms of their relative income position over the period 1985/86 to 1995/96, thus pushing the need for targeted social policy. This should cover targeted financial transfers as well as an improvement of day care for children. Although there are some signs of improvement concerning the integration process of foreigners' children over this period, the majority of this group still lives in rather poor conditions. There is no formal "discrimination" of immigrant children by the German school system. But due to the strong intergenerational correlation of educational attainment it is a problem that the educational level of immigrant parents as well as of foreign parents living in Germany is still clearly below the population average, although there are some signs of improvement. As a result of the low educational level of their parents we find children born to immigrants and foreigners in Germany to be on less favorable educational tracks more often than native born German children. The long-term problem arising from this will be a persistently high share of rather poorly qualified persons in the future work force, who will face severe labor market problems and as such will be a problem for the German economy as a whole. In other words: the German educational system -- including pre-school, school and vocational training -- needs to provide equal opportunities to all children regardless of their social background. If necessary, there should be additional incentives for children born to immigrants and foreigners to overcome language disadvantages.Children, Immigration, Living Conditions, Income Position, Poverty

Agent-oriented Modeling for Collaborative Learning Environments: A Peer-to-Peer Helpdesk Case Study

In this paper, we present the analysis and modelling of Help&Learn, an agent-based peer-to-peer helpdesk system to support extra-class interactions among students and teachers. Help&Learn expands the student’s possibility of solving problems, getting involved in a cooperative learning experience that transcends the limits of classrooms. To model Help&Learn, we have used Agent-Object-Relationship Modeling Language (AORML), an UML extension for agent-oriented information systems modeling. The aim of this research is two-fold. On one hand, we aim at modeling the variety of roles and the complexity of their interactions and activities within the Help&Learn system. On the other hand, we aim at showing the expressive power and the modeling strengths of AORML

A formal theory of cubical complexes Formal report, 1 Sep. 1968 - 30 Apr. 1969

Algorithm for computation of test failures in cyclic circuit

A Program for the Collection, Storage, and Analysis of Baseline Environmental Data for Cook Inlet, Alaska

The scope of this report is to provide a general, yet comprehensive, description of the Cook Inlet System which will serve as a basis for understanding the interrelated natural and man-made factors governing its future; to present a program of field research studies for the estuarine environment that will describe the existing state of the Inlet with respect to the water quality and biota; to provide a framework whereby the program of studies can be evaluated and redirected in light of the preliminary results; and, to provide a method of storing and analyzing the data from the investigations so that it can be made available to interested parties in the most efficient manner possible.This report was prepared by the Institute of Water Resources of the University of Alaska for the Alaska Water Laboratory, Federal Water Pollution Control Administration under Contract No. 14-12-449

The German Socio-Economic Panel Study (SOEP): Scope, Evolution and Enhancements

After the introduction in Section 2, we very briefly sketch out current theoretical and empirical developments in the social sciences. In our view, they all point in the same direction: toward the acute and increasing need for multidisciplinary longitudinal data covering a wide range of living conditions and based on a multitude of variables from the social sciences for both theoretical investigation and the evaluation of policy measures. Cohort and panel studies are therefore called upon to become truly interdisciplinary tools. In Section 3, we describe the German Socio-Economic Panel Study (SOEP), in which we discuss recent improvements of that study which approach this ideal and point out existing shortcomings. Section 4 concludes with a discussion of potential future issues and developments for SOEP and other household panel studies.SOEP, household panel studies, survey design