Polygon Exploration with Time-Discrete Vision

With the advent of autonomous robots with two- and three-dimensional scanning capabilities, classical visibility-based exploration methods from computational geometry have gained in practical importance. However, real-life laser scanning of useful accuracy does not allow the robot to scan continuously while in motion; instead, it has to stop each time it surveys its environment. This requirement was studied by Fekete, Klein and Nuechter for the subproblem of looking around a corner, but until now has not been considered in an online setting for whole polygonal regions. We give the first algorithmic results for this important algorithmic problem that combines stationary art gallery-type aspects with watchman-type issues in an online scenario: We demonstrate that even for orthoconvex polygons, a competitive strategy can be achieved only for limited aspect ratio A (the ratio of the maximum and minimum edge length of the polygon), i.e., for a given lower bound on the size of an edge; we give a matching upper bound by providing an O(log A)-competitive strategy for simple rectilinear polygons, using the assumption that each edge of the polygon has to be fully visible from some scan point.Comment: 28 pages, 17 figures, 2 photographs, 3 tables, Latex. Updated some details (title, figures and text) for final journal revision, including explicit assumption of full edge visibilit

Some shocking aspects of EMU enlargement

This paper uses a structural vector autoregression to examine differences in demand and supply shocks and the response to these shocks between EMU member countries and three other groups of countries. The first group includes non-EMU EU countries, the second group EFTA countries and the third group central and eastern European countries which seek EU membership over the next years. Our results suggest that, so far, EMU enlargement towards central and eastern European countries would involve significantly higher costs than EMU enlargement towards countries of the other two groups. --European Monetary Integration,International Monetary Arrangements and Institutions

Managing Diversity in virtuellen Teams – didaktische Strategien zur Unterstützung eines wertschätzenden Umgangs mit kultureller Vielfalt

Der Beitrag geht von der Idee aus, dass Unterschiedlichkeit von Menschen für die Gemeinschaft nicht nur Probleme schafft, sondern ein positives Potential in sich trägt. Dies entspricht der Grundannahme eines Management-Ansatzes, der in den letzten Jahren in der nordamerikanischen Wirtschaft zur Personalführung unter dem Schlagwort "Managing Diversity" entwickelt wurde. In dem Beitrag wird diese grundlegende Idee auf die Zusammenarbeit in interkulturellen virtuellen Teams angewandt. Dabei wird auf Erfahrungen zurückgegriffen, die in standortübergreifenden Lehrveranstaltungen für Studierende unterschiedlicher Fachkulturen und z.T. auch unterschiedlicher Muttersprachen gesammelt wurden. Es werden erste Hypothesen zu didaktischen Strategien der Unterstützung eines wertschätzenden Umgangs mit kultureller Vielfalt in studentischen virtuellen Teams präsentiert. (Der Artikel erscheint vorraussichtlich im Februar 2005 in: Beneke, Jürgen; Jarman, Francis: Interkulturalität in Wissenschaft und Praxis. Schriftenreihe der Universitätsbibliothek Hildesheim

The Value of Verbal Feedback in Allocation Decisions

Depending on the context at hand, people’s preference for receiving feedback might differ. Especially in allocation decisions that directly concern another individual, feedback from the affected person can have positive or negative value. We study such preferences in a laboratory experiment by eliciting the willingness-to-pay to receive or to avoid verbal feedback from subjects that were previously affected by an allocation decision. We find that most decision makers exhibit a positive willingness-to-pay for having control about whether feedback occurs or not. Specifically, decision makers that equally shared their endowment with the recipient revealed a positive willingness-to-pay for receiving, but not for avoiding feedback. By contrast, among decision makers that behaved selfishly, we identify both: subjects that were willing to pay for receiving and subjects that were willing to pay for avoiding feedback. The stated motivations indicate that curiosity, the desire to receive social approval and giving the recipient the chance to express his/her feelings are the main reasons for feedback acquisition, while shame and fear of negative feedback are the main reasons for avoidance

Fledermausquartiere an Gebäuden

In Sachsen leben 20 Fledermausarten. Viele besiedeln Quartiere in und an den verschiedensten Bauwerken. Gebäudebewohnende Fledermausarten sind durch Baumaßnahmen gefährdet, gleichzeitig wächst aber auch die Nachfrage von Bauherren nach fledermausfreundlichen Gebäuden. Die reich bebilderte Broschüre zeigt anhand von Beispielen aus ganz Sachsen, wie den Fledermäusen Quartiere in und an Gebäuden angeboten werden können. Detaillierte Bauzeichnungen und Anleitungen auf der beigefügten Mini-Disc bieten Anregungen, um mit Fledermäusen »unter einem Dach« zu wohnen

Selfie culture : An analysis of women's perceptions of selfie pictures

Because of the common use of picture editing programs for mass media content, such as advertising images, the Western beauty ideal has reached a more rigid and uniform standard. This has not only been proven to be linked to a negative body image, but also stands in close relation to the expectation for women to measure up to it. Even though it has become common knowledge that such media content is not a reflection of reality, selfies on social media networks prove that there are indeed women that embody the desired cultural beauty ideal. Over the past years social media networks, such as Instagram, have experienced a significant rise in popularity. Especially celebrities, but also a large amount of non-celebrities, use social media channels in order to promote themselves by sharing body pictures with other users. This thesis analyzes the effect selfie images of both, a celebrity and non-celebrity woman, have on female recipients. The main question of this research is: How do women feel about their own bodies when being confronted with images of bodies of non-celebrities, as well as celebrities? The conducted focus group interviews and the content and thematic analysis revealed that women do not necessarily experience a negative body image after encountering selfie images that conform to the beauty ideal. Instead, different factors were taken into consideration that allowed making distinctions between celebrities and non-celebrities. Specifically, when considering the circumstances of the different lifestyles, the beauty ideal and a perfect body became less relevant. In this regard, celebrities rely on posting such selfie images on social media platforms in order to uphold their image and maintain a certain status. In contrast non-celebrities were perceived to do so out of existing insecurities, such as depending on reassurance from others. However, even though the celebrity selfie was preferred based on aesthetic reasons, the non-celebrity selfie was more relatable because of its realistic appearance. The expressed perceptions towards the selfies also differed noticeably when considering the participants’ age as a variable

Fledermäuse: Jäger der Nacht

Fledermäuse gehören zu den besonders faszinierenden Tieren unserer Heimat. Alle 20 in Sachsen vorkommenden Arten sind streng geschützt. Die reich bebilderte Broschüre stellt diese Fledermausarten vor und informiert über Besonderheiten wie Wochenstuben, Wanderungen und verschiedene Quartiere in unserer Nachbarschaft. Fledermäuse brauchen Freunde. Die Gründe für den Rückgang betreffen sowohl das Quartierangebot in Gebäuden, Wäldern und unterirdischen Hohlräumen als auch den Zustand der Jagdgebiete. Mit der Einrichtung von Fledermausquartieren an Gebäuden können wir Fledermäusen helfen. Streuobstwiesen sind wertvolle Jagdgebiete und bieten einigen Arten Unterkunft. Auch den eigenen Garten können wir mit Obstbäumen, einheimischen Hecken und insektenreichen Wiesen fledermausfreundlich gestalten. Bestimmte Pflanzen (z. B. Nachtkerzen, Mondviolen) ziehen nachtaktive Insekten an und erhöhen das Nahrungsangebot