Experiences with Some Benchmarks for Deductive Databases and Implementations of Bottom-Up Evaluation

OpenRuleBench is a large benchmark suite for rule engines, which includes deductive databases. We previously proposed a translation of Datalog to C++ based on a method that "pushes" derived tuples immediately to places where they are used. In this paper, we report performance results of various implementation variants of this method compared to XSB, YAP and DLV. We study only a fraction of the OpenRuleBench problems, but we give a quite detailed analysis of each such task and the factors which influence performance. The results not only show the potential of our method and implementation approach, but could be valuable for anybody implementing systems which should be able to execute tasks of the discussed types.Comment: In Proceedings WLP'15/'16/WFLP'16, arXiv:1701.0014

The carrot or the stick: Self-regulation for gender-diverse boards via codes of good governance

Scholars have emphasized the potential of self-regulation, realized through "codes of good governance", to improve gender diversity on boards. Yet, unconvinced of the effectiveness of this self-regulation, many regulators have implemented mandatory quota laws. Our study sheds light on this dilemma. Seeking to broaden our conceptual knowledge of how such "codes" work in the specific case of gender diversity on boards, we ask: Under which conditions is self-regulation via voluntary principles of good governance effective? Expanding recent institutional-theory perspectives from the literature of women on boards, we show that, in the case of Austria, self-regulation via code recommendations is ineffective unless supported by additional forces. The primary reason for this, we argue, is that nominators do not expect benefits from gender-diverse boards. Furthermore, non-compliant companies face little pressure to change due to the small number of companies that have already adopted respective code recommendations. We identify two potential alternatives to boost the effectiveness of voluntary self-regulation for gender diverse boards: First, the introduction of concrete targets for female representation and the public monitoring of fulfillment; and, second, the establishment of a credible threat that mandatory quotas will be imposed if diversity goals are not achieved. Drawing on longitudinal data from 2006-2016 on listed and state-owned companies in Austria, we give an empirical account of the conditions that assure effective self-regulation. Arguing that codes suffer from what we call "opportunity bias", we conclude that political goals (such as gender equality) based on ethical rather than instrumental considerations are unlikely to be effectively implemented solely by codes of good governance

Nachfrage nach Öko-Lebensmitteln: Veränderung durch BSE?

Der erste deutsche BSE-Fall im November 2000 hat zu starken Veränderungen in der Lebensmittelnachfrage geführt. Der Rindfleischkonsum brach im Dezember 2000 und Januar 2001 um fast 70 Prozent im Vergleich zu den Vorjahresmonaten ein, während vor allem Geflügelfleisch, Fisch und Gemüse deutlich in der Verbrauchergunst stiegen (GfK, 2001). Auch der Markt für ökologisch erzeugte Lebensmittel profitierte von der deutschen BSE-Krise: Der Bundesverband Naturkost Naturwaren (BNN) meldete für das erste Halbjahr 2001 ein Umsatzwachstum von 36,5 Prozent gegenüber dem Vorjahreszeitraum (Rippin, 2002). Auch die Daten des ACNielsen Handelspanels zum Absatz von Bio-Frischmilch über den konventionellen Lebensmitteleinzelhandel (LEH) wiesen für Anfang 2001 ungewöhnlich hohe Wachstumsraten auf (Rippin, 2001). Handelt es sich bei diesen Beobachtungen möglicherweise um Anzeichen für ein verändertes Verbraucherbewusstsein gegenüber Lebensmitteln und insbesondere gegenüber ökologisch erzeugten Produkten? Diese und eine Reihe weiterer Fragen wurden in einer repräsentativen Verbraucherstudie der Universität Hamburg untersucht, bundesweit waren dazu 2 000 Personen im Alter von 18-75 Jahren im September 2001 befragt worden

Nachfrage nach Öko-Lebensmitteln: Ergebnisse einer repräsentativen Verbraucherstudie

Der erste deutsche BSE-Fall im November 2000 hat zu heftigen Reaktionen der Verbraucher bei der Nachfrage nach Lebensmitteln geführt. Der Rindfleischkonsum brach im Dezember 2000 und Januar 2001 um fast 70 % im Vergleich zu den Vorjahresmonaten ein, während Geflügelfleisch, Fisch, Gemüse und andere Beilagen deutlich in der Verbrauchergunst stiegen. Auch der Markt für ökologische Lebensmittel profitierte deutlich von der deutschen BSE-Krise. Vor diesem Hintergrund stellte sich die Frage, ob die genannten Veränderungen möglicherweise Ausdruck eines veränderten Verbraucherbewusstseins gegenüber Lebensmitteln – insbesondere gegenüber ökologisch erzeugten Produkten – sind. Die Beantwortung dieser und einer Reihe weiterer Fragen waren leitend für die Untersuchung

Annual report 2020/2021

Gedruckt erschienen im Universitätsverlag der TU Berlin, ISBN 978-3-7983-3238-6 (ISSN 2196-338X)Die Jahresberichte des Fachgebietes Lichttechnik informieren über Lehrveranstaltungen und aktuelle Forschungsvorhaben am Fachgebiet und geben einen Überblick über Mitarbeiter, Publikationen und Gremientätigkeiten.The annual reports of the Chair of Lighting Technology provide information on courses and current research projects and give an overview of the colleagues, their publications and committee activities

Multi-objective Analysis of Approaches to Dynamic Routing of a Vehicle

We consider a routing problem for a single vehicle serving customer Locations in the course of time. A subset of these customers must necessarily be served, while the complement of this subset contains dynamic customers which request for service over time, and which do not necessarily need to be served. The decision maker’s conflicting goals are serving as many customers as possible as well as minimizing total travel distance. We solve this bi-objective Problem with an evolutionary multi-objective algorithm in order to provide an a-posteriori evaluation tool for enabling decision makers to assess the single objective solution strategies that they actually use in real-time. We present the modifications to be applied to the evolutionary multi-objective algorithm NSGA2 in order to solve the routing problem, we describe a number of real-time single-objective solution strategies, and we finally use the gained efficient trade-off solutions of NSGA2 to exemplarily evaluate the real-time strategies. Our results show that the evolutionary multi-objective approach is well-suited to generate benchmarks for assessing dynamic heuristic strategies. Our findings point into future directions for designing dynamic multi-objective approaches for the vehicle routing problem with time windows

Anyone up for helping the Fisherman's wife? More solidarity with accidental misery than with man-made misery

We examine the willingness to donate depending on whether “misery” is random generated or self-inflicted by too high demands in bilateral negotiations. We find that randomness has a positive influence on the total amount of donation. In case of self-inflicted “misery” we observe that the subject who may have caused the unfavourable situation receives significantly less than the perceived innocent subject.altruism, bargaining experiment