The Fast Heuristic Algorithms and Post-Processing Techniques to Design Large and Low-Cost Communication Networks

It is challenging to design large and low-cost communication networks. In this paper, we formulate this challenge as the prize-collecting Steiner Tree Problem (PCSTP). The objective is to minimize the costs of transmission routes and the disconnected monetary or informational profits. Initially, we note that the PCSTP is MAX SNP-hard. Then, we propose some post-processing techniques to improve suboptimal solutions to PCSTP. Based on these techniques, we propose two fast heuristic algorithms: the first one is a quasilinear time heuristic algorithm that is faster and consumes less memory than other algorithms; and the second one is an improvement of a stateof-the-art polynomial time heuristic algorithm that can find high-quality solutions at a speed that is only inferior to the first one. We demonstrate the competitiveness of our heuristic algorithms by comparing them with the state-of-the-art ones on the largest existing benchmark instances (169 800 vertices and 338 551 edges). Moreover, we generate new instances that are even larger (1 000 000 vertices and 10 000 000 edges) to further demonstrate their advantages in large networks. The state-ofthe-art algorithms are too slow to find high-quality solutions for instances of this size, whereas our new heuristic algorithms can do this in around 6 to 45s on a personal computer. Ultimately, we apply our post-processing techniques to update the bestknown solution for a notoriously difficult benchmark instance to show that they can improve near-optimal solutions to PCSTP. In conclusion, we demonstrate the usefulness of our heuristic algorithms and post-processing techniques for designing large and low-cost communication networks

Ergebnisse der Besucherbefragung zur „Nacht der Museen“ in Hannover am 16. Juni 2012

Empirische Kulturnutzerforschung ist ein Instrument des Kulturmanagements mit dem das Erreichen von strategischen und operativen Marketingzielen überprüft werden kann. Das Institut für Kulturpolitik der Universität Hildesheim erhielt vom Kulturbüro der Stadt Hannover den Auftrag, eine Besucherbefragung anlässlich der „Nacht der Museen 2012“ durchzuführen. Ziel der Untersuchung war zum einen eine Evaluation der im Vorfeld durchgeführten Marketing-Maßnahmen

Descriptions of vestibular migraine and Meniere's disease in Greek and Chinese antiquity

Background: Vestibular migraine and Meniere's disease are two types of episodic vertigo syndromes that were already observed in Greek and Chinese antiquity. Descriptions first appeared in the work of the classical Greek physician Aretaeus of Cappadocia, who lived in the 2nd century AD, and in Huangdi Neijing, a seminal medical source in the Chinese Medical Classics, written between the 2nd century BC and the 2nd century AD. Aim: The aim of this paper is to search in Aretaeus' book De causis et signis acutorum et chronicorum morborum and in Huangdi Neijing for descriptions of vertigo co-occurring with headache or ear symptoms that resemble current classifications of vestibular migraine or Meniere's disease. Results: Aretaeus describes a syndrome combining headache, vertigo, visual disturbance, oculomotor phenomena, and nausea that resembles the symptoms of vestibular migraine. In the Chinese book Huangdi Neijing the Yellow Thearch mentions the co-occurrence of episodic dizziness and a ringing noise of the ears that recalls an attack of Meniere's disease. Conclusions: The descriptions of these two conditions in Greek and Chinese antiquity are similar to the vertigo syndromes currently classified as vestibular migraine and Meniere's disease. In clinical practice it may be difficult to clearly differentiate between them, and they may also co-occur

Amateur theatre in Lower Saxony.A study on the conditions and procedures of amateur theaters.

In zahlreichen Städten und Gemeinden in Niedersachsen wird Theater gespielt. Die Mitglieder dieser Amateurtheater wählen gemeinsam Stücke aus, proben regelmäßig nach Feierabend, bauen selbst das Bühnenbild, schneidern die Kostüme und führen schließlich mit vielen Helfern in Dorfgemeinschaftshäusern oder Gaststätten ihre überwiegend heiteren Stücke auf. Im Publikum sitzen vor allem Menschen aus dem gleichen Ort oder der näheren Umgebung. Nach dem Kulturmonitoring Niedersachsen praktizieren 9 % der Bevölkerung in Niedersachsen ‚Theater spielen‘ als künstlerisch-kreative Freizeitbeschäftigung. Obgleich die Theaterlandschaft in Niedersachsen – und vermutlich auch in den anderen Bundesländern – sehr stark von dieser Art des Theaters geprägt ist, existieren kaum wissenschaftliche Erkenntnisse darüber, in welchen Strukturen Amateurtheater stattfindet und wie sich dieses weiterentwickeln kann. Auch sind Amateurtheater nur selten Gegenstand kulturpolitischer Diskussionen. Erstmalig wurden mit dieser Studie systematisch und landesweit empirisch repräsentative Daten zu Strukturen, Theaterarbeit, finanzieller Situation und zukünftigen Herausforderungen von Amateurtheatern erhoben

The Effect of Health Changes and Long-term Health on the Work Activity of Older Canadians

Using longitudinal data from the Canadian National Population Health Survey (NPHS), we study the relationship between health and employment among older Canadians. We focus on two issues: (1) the possible endogeneity of self- reported health, particularly "justification bias", and (2) the relative importance of health changes and long-term health in the decision to work. The NPHS contains the HUI3, an "objective" health index which has been gaining popularity in empirical work. We contrast estimates of the impact of health on employment using self-assessed health, the HUI3, and a "purged" health measure similar to that employed by Bound et al. (1999) and Disney et al. (2003). A direct test suggests that self-assessed health suffers from justification bias. However, the HUI3 provides estimates that are similar to the "purged" health measure. We also corroborate recent U.S. and U.K. findings that changes in health are important in the work decision.Health; Health Changes; Employment; Older Workers; NPHS

The Effect of Health Changes and Long-term Health on the Work Activity of Older Canadians

Using longitudinal data from the Canadian National Population Health Survey (NPHS), we study the relationship between health and employment among older Canadians. We focus on two issues: (1) the possible problems with self- reported health, including endogeneity and measurement error, and (2) the relative importance of health changes and long-term health in the decision to work. We contrast estimates of the impact of health on employment using self-assessed health, an objective health index contained in the NPHS - the HUI3, and a "purged" health stock measure. Our results suggest that health has an economically significant effect on employment probabilities for Canadian men and women aged 50 to 64, and that this effect is underestimated by simple estimates based on self-assessed health. We also corroborate recent U.S. and U.K. findings that changes in health are important in the work decision.health, health changes, employment, older workers