On the Structure and Complexity of Rational Sets of Regular Languages

In a recent thread of papers, we have introduced FQL, a precise specification language for test coverage, and developed the test case generation engine FShell for ANSI C. In essence, an FQL test specification amounts to a set of regular languages, each of which has to be matched by at least one test execution. To describe such sets of regular languages, the FQL semantics uses an automata-theoretic concept known as rational sets of regular languages (RSRLs). RSRLs are automata whose alphabet consists of regular expressions. Thus, the language accepted by the automaton is a set of regular expressions. In this paper, we study RSRLs from a theoretic point of view. More specifically, we analyze RSRL closure properties under common set theoretic operations, and the complexity of membership checking, i.e., whether a regular language is an element of a RSRL. For all questions we investigate both the general case and the case of finite sets of regular languages. Although a few properties are left as open problems, the paper provides a systematic semantic foundation for the test specification language FQL

Observations of shallow convective clouds generated by solar heating of dark smoke plumes

The SEVIRI instrument on the Meteosat Second Generation satellite with both fine spatial and temporal resolution allows to detect and follow the dynamics of fast developing meteorological events like spreading smoke plumes and the lifecycles of convective clouds. Smoke plumes have the ability to change the atmospheric heat content due to absorption and reduced reflection of solar radiation. By these means they can trigger formation of shallow convective clouds at their edge. A heavy smoke plume emerging from burning Lebanese oil tanks and spreading over adjacent deserts on 17 July 2006 has been observed as an example of such an effect. This study suggests a physical explanation of the observed convection along the edge of the smoke plume, namely the strong thermal contrast resulting from solar heating of the smoke layer

Options and Barriers in Implementing International Climate Change Agreements - A Benefits-Costs Approach on the example of technology cooperation

Die Dissertation beleuchtet aus ökonomischer Sicht die Thematik des Klimawandels mit dem Ziel, Ansätze einer technologischen Kooperation zu identifizieren, die zu einer Verbesserung der Nutzen-Kosten-Relation in internationalen Klimaschutzverhandlungen beitragen könnten. Besonderer Wert wird hierbei auf das politische Umfeld und die Implementierbarkeit einzelner Vorschläge gelegt. Die Arbeit besteht aus sechs Kapiteln (Einführung und fünf Beiträge), die als selbständige Aufsätze konzipiert und z.T. in englischer Sprache verfasst sind. Kapitel 1 liefert eine Hinführung zum Thema, der Motivation und der Zielrichtung der Arbeit. Darüber hinaus wird eine Architektur ökonomischer Analysen der Klimaschutzproblematik skizziert, die helfen soll, die Komplexität der Problems „Klimawandel“ aus ökonomischer Sicht aufzuzeigen bzw. zu strukturieren. In den folgenden beiden Kapiteln werden die Zielgestaltung internationaler Klimaschutzpolitik (Kapitel 2) sowie deren institutionelle Ausgestaltung (Kapitel 3) anhand ökonomischer Kriterien analysiert. Im Hinblick auf die Identifizierung von Ansätzen, die (im weiteren Sinne) als Mechanismen einer Technologiekooperation im gegenwärtigen System betrachtet werden können untersucht die Arbeit in Kapitel 4 den Einfluss des Clean Development Mechanism (CDM) auf den Transfer von Technologien. In Kapitel 5 werden mögliche Ausgestaltungsformen technologischer Kooperation innerhalb eines zukünftigen Klimaschutzabkommen diskutiert. Kapitel 6 konzentriert sich auf die tatsächlichen Entwicklungen in den gegenwärtigen Klimaschutzverhandlungen für ein Folgeabkommen unter dem Dach der Klimarahmenkonvention der Vereinten Nationen (UNFCCC). Basierend auf einer im Umfeld der 13. Klimarahmenkonferenz auf Bali, Indonesien, durchgeführten qualitativen Erhebung werden verschiedene Instrumente einer technologischen Kooperation analysiert und hinsichtlich ihrer Implementierungschancen und (Anreiz-)Wirkungen geprüft

Multi-Head Finite Automata: Characterizations, Concepts and Open Problems

Multi-head finite automata were introduced in (Rabin, 1964) and (Rosenberg, 1966). Since that time, a vast literature on computational and descriptional complexity issues on multi-head finite automata documenting the importance of these devices has been developed. Although multi-head finite automata are a simple concept, their computational behavior can be already very complex and leads to undecidable or even non-semi-decidable problems on these devices such as, for example, emptiness, finiteness, universality, equivalence, etc. These strong negative results trigger the study of subclasses and alternative characterizations of multi-head finite automata for a better understanding of the nature of non-recursive trade-offs and, thus, the borderline between decidable and undecidable problems. In the present paper, we tour a fragment of this literature

Algebraic Methods in the Congested Clique

In this work, we use algebraic methods for studying distance computation and subgraph detection tasks in the congested clique model. Specifically, we adapt parallel matrix multiplication implementations to the congested clique, obtaining an $O(n^{1-2/\omega})$ round matrix multiplication algorithm, where $\omega < 2.3728639$ is the exponent of matrix multiplication. In conjunction with known techniques from centralised algorithmics, this gives significant improvements over previous best upper bounds in the congested clique model. The highlight results include: -- triangle and 4-cycle counting in $O(n^{0.158})$ rounds, improving upon the $O(n^{1/3})$ triangle detection algorithm of Dolev et al. [DISC 2012], -- a $(1 + o(1))$-approximation of all-pairs shortest paths in $O(n^{0.158})$ rounds, improving upon the $\tilde{O} (n^{1/2})$-round $(2 + o(1))$-approximation algorithm of Nanongkai [STOC 2014], and -- computing the girth in $O(n^{0.158})$ rounds, which is the first non-trivial solution in this model. In addition, we present a novel constant-round combinatorial algorithm for detecting 4-cycles.Comment: This is work is a merger of arxiv:1412.2109 and arxiv:1412.266

The Most Cited Papers in Osteoporosis and Related Research

Osteoporosis is a systemic disease of the bone that affects millions of people and causes burden for both the affected individual and health systems and societies worldwide. Since the 1970s much research has been done in the field of osteoporosis. The number of citations of a paper reflects its influence and importance to the field. Thomson ISI Web of Science database was searched to retrieve a list of the fifty most cited articles related to osteoporosis and its research. The fifty most cited articles in absolute numbers in the field of osteoporosis were cited from 877 to 3056 times (mean 1141±537). Most papers were published in the basic science category (n=23). 395 authors contributed; a single paper had between one and 62 authors (mean: 10.02±9.9 authors). 12 authors (3.04%) contributed between 7 and 4 papers; 340 authors (86.1%) were at least named once. Corresponding authors were from eight countries with most contributions from the United States (n=34, 68%). The majority of papers were published in the 1990s (n=29). The list of 50 most cited papers presents citation classics in the field of osteoporosis and related research

The worse we feel, the more intensively we need to stick together: a qualitative study of couples’ emotional co-regulation of the challenge of multimorbidity

IntroductionBeing faced with multimorbidity (i.e., being diagnosed with at least two chronic conditions), is not only demanding in terms of following complicated medical regimes and changing health behaviors. The changes and threats involved also provoke emotional responses in the patients but also in their romantic partners. This study aims at exploring the ways of emotional co-regulation that couples facing multimorbidity express when interviewed together.MethodN = 15 opposite sex couples with one multimorbid patient after an acute health crisis that led to hospitalization were asked in a semi-structured interview about how they found ways to deal with the health situation, what they would recommend to other couples in a similar situation, and how they regulated their emotional responses. Interviews were analyzed qualitatively following open, axial, and selective coding, as in the grounded theory framework.ResultsEmerging categories from the romantic partners’ and the patients’ utterances revealed three main categories: First, overlapping cognitive appraisals about the situation (from fighting spirit to fatalism) and we-ness (construing the couple self as a unit) emerged as higher order factor from the utterances. Second, relationship-related strategies including strategies aimed at maintaining high relationship quality in spite of the asymmetric situation like strengthening the common ground and balancing autonomy and equity in the couple were often mentioned. Third, some couples mentioned how they benefit from individual strategies that involve fostering individual resources of the partners outside the couple relationship (such as cultivating relationships with grandchildren or going outdoors to nature).DiscussionResults underline the importance of a dyadic perspective not only on coping with disease but also on regulating the emotional responses to this shared challenging situation. The utterances of the couples were in line with earlier conceptualizations of interpersonal emotion regulation and dyadic perspectives on we-disease. They broaden the view by integrating the interplay between individual and interpersonal regulation strategies and underline the importance of balancing individual and relational resources when supporting couples faced with chronic diseases

Multi-variate time-series for time constraint adherence prediction in complex job shops

One of the most complex and agile production environments is semiconductor manufacturing, especially wafer fabrication, as products require more than several hundred operations and remain in Work-In-Progress for months leading to complex job shops. Additionally, an increasingly competitive market environment, i.e. owing to Moore’s law, forces semiconductor companies to focus on operational excellence, resiliency and, hence, leads to product quality as a decisive factor. Product-specific time constraints comprising two or more, not necessarily consecutive, operations ensure product quality at an operational level and, thus, are an industry-specific challenge. Time constraint adherence is of utmost importance, since violations typically lead to scrapping entire lots and a deteriorating yield. Dispatching decisions that determine time constraint adherence are as a state of the art performed manually, which is stressful and error-prone. Therefore, this article presents a data-driven approach combining multi-variate time-series with centralized information to predict time constraint adherence probability in wafer fabrication to facilitate dispatching. Real-world data is analyzed and different statistical and machine learning models are evaluated