Limit Your Consumption! Finding Bounds in Average-energy Games

Energy games are infinite two-player games played in weighted arenas with quantitative objectives that restrict the consumption of a resource modeled by the weights, e.g., a battery that is charged and drained. Typically, upper and/or lower bounds on the battery capacity are part of the problem description. Here, we consider the problem of determining upper bounds on the average accumulated energy or on the capacity while satisfying a given lower bound, i.e., we do not determine whether a given bound is sufficient to meet the specification, but if there exists a sufficient bound to meet it. In the classical setting with positive and negative weights, we show that the problem of determining the existence of a sufficient bound on the long-run average accumulated energy can be solved in doubly-exponential time. Then, we consider recharge games: here, all weights are negative, but there are recharge edges that recharge the energy to some fixed capacity. We show that bounding the long-run average energy in such games is complete for exponential time. Then, we consider the existential version of the problem, which turns out to be solvable in polynomial time: here, we ask whether there is a recharge capacity that allows the system player to win the game. We conclude by studying tradeoffs between the memory needed to implement strategies and the bounds they realize. We give an example showing that memory can be traded for bounds and vice versa. Also, we show that increasing the capacity allows to lower the average accumulated energy.Comment: In Proceedings QAPL'16, arXiv:1610.0769

Pitfalls of Immigrant Inclusion into the European Welfare State

This paper's main purpose is to gauge immigrants' demand for social assistance and services and identify the key barriers to social and labor market inclusion of immigrants in the European Union. The data from an online primary survey of experts from organizations working on immigrant integration in the EU is analyzed using simple comparative statistical methods; the robustness of the results is tested by means of Logit and ordered Logit statistical models. We find that the general public in Europe has rather negative attitudes towards immigrants. Although the business community views immigrants somewhat less negatively, barriers to immigrant labor market inclusion identified include language and human capital gaps, a lack of recognition of foreign qualifications, discrimination, intransparent labor markets and institutional barriers such as legal restrictions for foreign citizens. Exclusion from higher education, housing and the services of the financial sector aggravate these barriers. Changes in the areas of salaried employment, education, social insurance, mobility and attitudes are seen as most desired by members of ethnic minorities. The current economic downturn is believed to have increased the importance of active inclusion policies, especially in the areas of employment and education. These results appear to be robust with respect to a number of characteristics of respondents and their organizations.ethnic minorities, migration, labor market integration, economic crisis, enlarged European Union, welfare state

Beam-beam simulation code BBSIM for particle accelerators

A highly efficient, fully parallelized, six-dimensional tracking model for simulating interactions of colliding hadron beams in high energy ring colliders and simulating schemes for mitigating their effects is described. The model uses the weak-strong approximation for calculating the head-on interactions when the test beam has lower intensity than the other beam, a look-up table for the efficient calculation of long-range beam-beam forces, and a self-consistent Poisson solver when both beams have comparable intensities. A performance test of the model in a parallel environment is presented. The code is used to calculate beam emittance and beam loss in the Tevatron at Fermilab and compared with measurements. We also present results from the studies of two schemes proposed to compensate the beam-beam interactions: a) the compensation of long-range interactions in the Relativistic Heavy Ion Collider (RHIC) at Brookhaven and the Large Hadron Collider (LHC) at CERN with a current-carrying wire, b) the use of a low energy electron beam to compensate the head-on interactions in RHIC

Beratung zum pränatalen Alkoholkonsum : der Einfluss von Kurzinterventionen auf den Alkoholkonsum während der Schwangerschaft

Darstellung des Themas: Alkoholkonsum in der Schwangerschaft kann zu schwerwiegenden, irreversiblen Schädigungen beim (ungeborenen) Kind führen, welche durch eine strikte maternale Alkoholabstinenz vermeidbar wären. Die Kurzintervention stellt eine mögliche Interventionsmöglichkeit bei Alkoholkonsum dar. Ziel: Ziel dieser Bachelorarbeit ist es, die in der Literatur beschriebene Wirksamkeit von Kurzinterventionen bei alkoholkonsumierenden schwangeren Frauen aufzuzeigen. Daraus wird von den Autorinnen ein Modell zur praktischen Anwendung für die Hebamme zur Beratung von alkoholkonsumierenden schwangeren Frauen abgeleitet. Methode: Es wurde eine Literaturrecherche auf verschiedenen Datenbanken durchgeführt. Vier für die Fragestellung relevante Studien wurden gefunden, bewertet und miteinander diskutiert. Relevante Ergebnisse: Durch die Anwendung von Kurzinterventionen während der Schwangerschaft kann der leichte bis moderate pränatale Alkoholkonsum reduziert, beziehungsweise eingestellt werden und das kindliche Outcome verbessert werden. Der Effekt wird durch Einbezug eines Partners oder einer Partnerin in der ersten Schwangerschaftskontrolle mittels konkreter Zielsetzung verstärkt. Schlussfolgerung: Es ist wichtig, dass alkoholkonsumierende schwangere Frauen identifiziert und über die Thematik aufgeklärt werden. Für eine optimale Betreuung sollten Hebammen in der Beratung zu pränatalem Alkoholkonsum geschult werden. Ein geeigneter Interventionsansatz stellt das von den Ergebnissen dieser Bachelorarbeit abgeleitete Beratungsmodell zum pränatalen Alkoholkonsum für Hebammen dar

Phase-field simulations of solidification in binary and ternary systems using a finite element method

We present adaptive finite element simulations of dendritic and eutectic solidification in binary and ternary alloys. The computations are based on a recently formulated phase-field model that is especially appropriate for modelling non-isothermal solidification in multicomponent multiphase systems. In this approach, a set of governing equations for the phase-field variables, for the concentrations of the alloy components and for the temperature has to be solved numerically, ensuring local entropy production and the conservation of mass and inner energy. To efficiently perform numerical simulations, we developed a numerical scheme to solve the governing equations using a finite element method on an adaptive non-uniform mesh with highest resolution in the regions of the phase boundaries. Simulation results of the solidification in ternary Ni$_{60}$Cu$_{40-x}$Cr$_{x}$ alloys are presented investigating the influence of the alloy composition on the growth morphology and on the growth velocity. A morphology diagram is obtained that shows a transition from a dendritic to a globular structure with increasing Cr concentrations. Furthermore, we comment on 2D and 3D simulations of binary eutectic phase transformations. Regular oscillatory growth structures are observed combined with a topological change of the matrix phase in 3D. An outlook for the application of our methods to describe AlCu eutectics is given.Comment: 5 pages, 3 figures, To appear in the proceedings of 14th "International Conference on Crystal Growth", ICCG-14, 9-13 August 2004 Grenoble Franc

Force Characteristics of In Vivo Tissue-engineered Myocardial Constructs Using Varying Cell Seeding Densities

Experiments have been successfully performed culminating in functional, vascularized, three-dimensional cardiac muscle tissue. Past experience in tissue engineering has led us to the understanding that cell seeding density plays a critical role in the formation and function of both in vitro and in vivo engineered tissues. Therefore, to improve upon the mechanics of this model and to facilitate the formation of myocardial tissue with improved functional performance, we sought to optimize the seeding density of cardiomyocytes in these constructs. Neonatal cardiac myocytes were isolated from 2-day-old Fischer 344 rat hearts. Silicone chambers containing fibrin gel were seeded with varying numbers of cardiac cells (1, 5, 10, and 20 million). Control chambers were prepared using fibrin gel alone. All of the chambers were then implanted around the femoral vessels of isogenic rats. Six constructs per cell seeding density group were implanted. Histological and immunohistochemical evaluation was performed via hematoxylin and eosin, von Gieson, and α-sarcomeric actin staining protocols. Linear contractile force measurements were obtained for each construct following 4 weeks of in vivo implantation. After an implantation period of 4 weeks, the newly formed cardiac constructs contained within the chambers were harvested. The femoral vessels within the constructs were found to be patent in all cases. With direct electrical stimulation, the constructs were able to generate an average active force that varied depending on their seeding density. Constructs with seeding densities of 1, 5, 10, and 20 million cells produced an average active force of 208, 241, 151, and 108 µN, respectively. The control constructs did not generate any active force on electrical stimulation. This study demonstrates the in vivo survival, vascularization, organization, and function of transplanted myocardial cells. It is also apparent that cell seeding density plays a direct role in the force generation and mechanical properties of these engineered constructs. Among different groups using varying cell seeding densities, we found that the group with 5 million cells generated maximum active force.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/72542/1/j.1525-1594.2008.00591.x.pd

Traces of stimulated bosonic exciton-scattering in semiconductor luminescence

We observe signatures of stimulated bosonic scattering of excitons, a precursor of Bose-Einstein-Condensation (BEC), in the photoluminescence of semiconductor quantum wells. The optical decay of a spinless molecule of two excitons (biexciton) into an exciton and a photon with opposite angular momenta is subject to bosonic enhancement in the presence of other excitons. In a spin polarized gas of excitons the bosonic enhancement breaks the symmetry of two equivalent decay channels leading to circularly polarized luminescence of the biexciton with the sign opposite to the excitonic luminescence. Comparison of experiment and many body theory proves stimulated scattering of excitons, but excludes the presence of a fully condensed BEC-like state.Comment: 5 page

Si photonic-electronic monolithically integrated optical receiver with a built-in temperature-controlled wavelength filter

We present a Si photonic-electronic integrated ring-resonator based optical receiver that contains a temperature-controlled ring-resonator filter (RRF), a Ge photodetector, and receiver circuits in a single chip. The temperature controller automatically determines the RRF temperature at which the maximum transmission of the desired WDM signal is achieved and maintains this condition against any temperature or input wavelength fluctuation. This Si photonic-electronic integrated circuit is realized with 0.25-µm photonic BiCMOS technology, and its operation is successfully confirmed with measurement

Don't trust your eyes: on the (un)reliability of feature visualizations

How do neural networks extract patterns from pixels? Feature visualizations attempt to answer this important question by visualizing highly activating patterns through optimization. Today, visualization methods form the foundation of our knowledge about the internal workings of neural networks, as a type of mechanistic interpretability. Here we ask: How reliable are feature visualizations? We start our investigation by developing network circuits that trick feature visualizations into showing arbitrary patterns that are completely disconnected from normal network behavior on natural input. We then provide evidence for a similar phenomenon occurring in standard, unmanipulated networks: feature visualizations are processed very differently from standard input, casting doubt on their ability to "explain" how neural networks process natural images. We underpin this empirical finding by theory proving that the set of functions that can be reliably understood by feature visualization is extremely small and does not include general black-box neural networks. Therefore, a promising way forward could be the development of networks that enforce certain structures in order to ensure more reliable feature visualizations