Finite order automorphisms and real forms of affine Kac-Moody algebras in the smooth and algebraic category

Automorphisms of finite order and real forms of "smooth" affine Kac-Moody algebras are studied, i.e. of 2-dimensional extensions of the algebra of smooth loops in a simple Lie algebra. It is shown that they can be parametrized by certain invariants and that in particular the classification of involutions essentially follows from Cartan's classifications in finite dimensions. We also prove that our approach works equally well in the usual algebraic setting and leads to the same results there

IIFA: Modular Inter-app Intent Information Flow Analysis of Android Applications

Android apps cooperate through message passing via intents. However, when apps do not have identical sets of privileges inter-app communication (IAC) can accidentally or maliciously be misused, e.g., to leak sensitive information contrary to users expectations. Recent research considered static program analysis to detect dangerous data leaks due to inter-component communication (ICC) or IAC, but suffers from shortcomings with respect to precision, soundness, and scalability. To solve these issues we propose a novel approach for static ICC/IAC analysis. We perform a fixed-point iteration of ICC/IAC summary information to precisely resolve intent communication with more than two apps involved. We integrate these results with information flows generated by a baseline (i.e. not considering intents) information flow analysis, and resolve if sensitive data is flowing (transitively) through components/apps in order to be ultimately leaked. Our main contribution is the first fully automatic sound and precise ICC/IAC information flow analysis that is scalable for realistic apps due to modularity, avoiding combinatorial explosion: Our approach determines communicating apps using short summaries rather than inlining intent calls, which often requires simultaneously analyzing all tuples of apps. We evaluated our tool IIFA in terms of scalability, precision, and recall. Using benchmarks we establish that precision and recall of our algorithm are considerably better than prominent state-of-the-art analyses for IAC. But foremost, applied to the 90 most popular applications from the Google Playstore, IIFA demonstrated its scalability to a large corpus of real-world apps. IIFA reports 62 problematic ICC-/IAC-related information flows via two or more apps/components

A Unifying Theory for Nonlinear Additively and Multiplicatively Preconditioned Globalization Strategies : Convergence Results and Examples From the Field of Nonlinear Elastostatics and Elastodynamics

Nonlinear right preconditioned globalization strategies for the solution of nonlinear programming problems of the following kind $u \in \mathcal B \subset \mathbb R^n: J(u) = \min!$ where $\mathcal B$ is a convex set of admissible solutions, $n\in \mathbb N$, and $J: \mathbb R^n \to \mathbb R$, sufficiently smooth, are presented. Preconditioned globalization strategies are traditional Linesearch or Trust-Region strategies in combination with a nonlinear update operator which results from a nonlinear solution process for smaller, but related, nonlinear programming problems. We will formulate conditions on this abstract operator, in order to ensure global convergence, i.e., convergence to first-order critical points, of the resulting method. In addition, we introduce particular implementations of this abstract operator, i.e., nonlinear multiplicatively preconditioned Trust-Region (MPTS) and Linesearch strategies (MPLS), as well as nonlinear additively preconditioned Trust-Region (APTS) and Linesearch (APLS) strategies. As it turns out, these additive strategies are novel parallel, locally adaptive and robust solution methods for nonlinear programming problems. Moreover, the MPTS strategy generalizes the RMTR concepts in [GK08] in order to allow also for the application of alternating nonlinear domain decomposition methods. On the other hand, the MPLS method simplifies and generalizes the concepts in [WG08] giving rise to a novel solution strategy for pointwise constrained nonlinear programming problems. The respective nonlinear solution strategies are analyzed and global convergence is shown. In addition, global convergence is also shown for combined nonlinear additively and multiplicatively preconditioned Trust-Region and Linesearch strategies. Moreover, we show the efficiency and reliability of these methods in the context of problems arising from the field of nonlinear elasticity in 3d. Particular emphasis has been placed on the formulation and analysis of the resulting minimization problems. Here, we show that these problems satisfy the assumptions stated to show convergence of the respective preconditioned globalization strategies. Moreover, various elasto-static and elasto-dynamic examples are presented in order to compare the convergence rates and runtimes of the different strategies

Fingerprints for spin-selection rules in the interaction dynamics of O2 at Al(111)

We performed mixed quantum-classical molecular dynamics simulations based on first-principles potential-energy surfaces to demonstrate that the scattering of a beam of singlet O2 molecules at Al(111) will enable an unambiguous assessment of the role of spin-selection rules for the adsorption dynamics. At thermal energies we predict a sticking probability that is substantially less than unity, with the repelled molecules exhibiting characteristic kinetic, vibrational and rotational signatures arising from the non-adiabatic spin transition.Comment: 4 pages including 3 figures; related publications can be found at http://www.fhi-berlin.mpg.de/th/th.htm

Touristic signage on German Autobahns: Perception and reception of touristic roadside signage

There is an ever-increasing number of touristic brown signs on German Autobahns. According to the Guidelines for Touristic Signage, these are supposed to both provide information on destinations of touristic interest and to give directions to the locations in question. However, whether or not they are actually noticed by drivers, whether drivers can remember these signs and the Points of Interest (PoI) shown on them, and whether they influence the drivers’ decision-making behaviour have as yet not been scientifically investigated. For the first time, an online survey now provides information on the answers to these questions

Signatures of nonadiabatic O2 dissociation at Al(111): First-principles fewest-switches study

Recently, spin selection rules have been invoked to explain the discrepancy between measured and calculated adsorption probabilities of molecular oxygen reacting with Al(111). In this work, we inspect the impact of nonadiabatic spin transitions on the dynamics of this system from first principles. For this purpose the motion on two distinct potential-energy surfaces associated to different spin configurations and possible transitions between them are inspected by means of the Fewest Switches algorithm. Within this framework we especially focus on the influence of such spin transitions on observables accessible to molecular beam experiments. On this basis we suggest experimental setups that can validate the occurrence of such transitions and discuss their feasibility.Comment: 13 pages, 7 figure

Return and volatility reactions to monthly announcements of business cycle forecasts : an event study based on high-frequency data

This article contributes to the literature on macroeconomic announcements and their impact on asset prices by investigating how the 15-second Xetra DAX returns reflect the monthly announcements of the two best known business cycle forecasts for Germany, i.e. the ifo Business Climate Index and the ZEW Indicator of Economic Sentiment. From the methodological point of view, the main innovation lies in disentangling "good" macroeconomics news from "bad" news, and, simultaneously, considering time intervals with and without confounding announcements from other sources. Releases from both institutes lead to an immediate response of returns occurring 15 seconds after the announcements, i.e. within the first possible time interval. Announcements of both institutes are also clearly and immediately reflected in the volatility, which remains at a significantly higher level for approximately two minutes slightly elevated for approximately 15 minutes. Combining returns and volatility in a GARCH(1,1)-model, the paper reveals that significant increases in volatility only show up in the presence of simultaneous news released by other sources, whereas return reactions can be observed irrespective of whether confounding announcements are published or not

Spin squeezing and non-linear atom interferometry with Bose-Einstein condensates

Interferometry is the most precise measurement technique known today. It is based on interference and therefore on the wave-like nature of the resources – photons or atoms – in the interferometer. As given by the laws of quantum mechanics the granular, particle-like features of the individually independent atoms or photons are responsible for the precision limit – the shot noise limit. However this “classical” bound is not fundamental and it is the aim of quantum metrology to overcome it by employing quantum correlations – entanglement – among the particles. We report on the realization of spin squeezed states suitable for atom interferometry based on two external modes of a Bose-Einstein condensate. We detect manybody entangled states which allow – in principle – for a precision gain of 35% over the shot noise limit in atom interferometry. We demonstrate a novel non-linear atom interferometer for Bose-Einstein condensates whose linear analog – the Ramsey interferometer – is used for the definition of the time standard. Within the non-linear interferometer we detect a large entangled state of 170 inseparable atoms. A measurement with this interferometer outperforms its ideal linear analog by 15% in phase estimation precision showing directly the feasibility of non-linear atom interferometry with Bose-Einstein condensates beyond “classical” precision limits

2011,04: Explaining the (non-) causality between energy and economic growth in the US : a multivariate sectoral analysis

The rapidly growing literature on the relationship between energy consumption and economic growth has not univocally identified the "real" causal relationship yet. We argue that bivariate models, which analyze the causality at the level of the total economy, are not appropriate - especially in cases where both variables do not cover the same scope of economic activity. After discussing appropriate pairs of variables, we investigate Granger causality between energy consumption and GDP in the U.S. for the period from 1970 to 2007 for three sectors - industry, commercial sector, transport as well as for the total economy. The choice of additional variables is based on major findings from the Environmental Kuznets curve literature and its critical reflections. Using the recently developed ARDL bounds testing approach by Pesaran and Shin (1999) and Pesaran et al. (2001), we find evidence for long-run Granger causality for the commercial sector, in case energy is the dependent variable, as well as bi-directional long-run Granger causality for the transport sector. We conclude that controlling for trade as well as increasing energy productivity significantly improves the fit of several extensions of the bivariate model

Reappraising the role of energy in the economy

Die Bedeutung des Energiekonsums für das Wirtschaftswachstum ist zurück auf der Agenda. Erstmalig ist dessen Bedeutung nach der Ölpreiskrise in den 1970er Jahren in das Zentrum der Betrachtung gerückt. Zwei neue Entwicklungen haben das Interesse an der Thematik wieder aufleben lassen. Zum einen lässt sich seit der Jahrtausendwende ein kontinuierlicher Anstieg der Energiepreise feststellen. Die wachsende Energienachfrage der gegenwärtig industrialisierenden Länder überkompensiert die Effizienzgewinne des Energiekonsums, der erzielt werden konnte. Gleichzeitig gibt es Berechnungen wonach die Ölgewinnung den Höhepunkt erreicht hat, was die Befürchtungen über eine Verknappung der weltweiten Ölreserven noch verstärkt. Zum anderen gibt es ein stärkeres Bewusstsein für die Schädigungen der Umwelt aufgrund des zunehmenden Verbrauchs fossiler Energieressourcen sowie der damit verbundene Erhöhung der CO2-Konzentration in der Atmosphäre. Wie haben wir bislang auf diese Entwicklung reagiert? Es gibt sehr optimistische Szenarien, wonach das Wirtschaftswachstum weitestgehend vom Energiekonsum entkoppelt werden kann. Gleichzeitig gibt es Einschätzungen wonach die CO2 Emissionen vom Energiekonsum entkoppelt werden können. Von empirischer Seite gibt es wenig eindeutige Belege für die Kopplung von Energie und Wachstum. Das verbindende Element der empirischen Untersuchungen, die dieser Dissertation zugrunde liegen, ist sowohl eine kritische Auseinandersetzung mit den Möglichkeiten, die beschriebene Entkopplung zu erreichen als auch eine empirische Analyse des tatsächlichen Potenzials für eine Entkopplung