06172 Abstracts Collection -- Directed Model Checking

From 26.04.06 to 29.04.06, the Dagstuhl Seminar 06172 ``Directed Model Checking\u27\u27 was held in the International Conference and Research Center (IBFI), Schloss Dagstuhl. During the seminar, several participants presented their current research, and ongoing work and open problems were discussed. Abstracts of the presentations given during the seminar as well as abstracts of seminar results and ideas are put together in this paper. The first section describes the seminar topics and goals in general. Links to extended abstracts or full papers are provided, if available

Protocol verification with heuristic search

We present an approach to reconcile explicit state model checking and heuristic directed search and provide experimental evidence that the model checking problem for concurrent systems, such as communications protocols, can be solved more efficiently, since finding a state violating a property can be understood as a directed search problem. In our work we combine the expressive power and implementation efficiency of the SPIN model checker with the HSF heuristic search workbench, yielding the HSF-SPIN tool that we have implemented. We start off from the A* algorithm and some of its derivatives and define heuristics for various system properties that guide the search so that it finds error states faster. In this paper we focus on safety properties and provide heuristics for invariant and assertion violation and deadlock detection. We provide experimental results for applying HSF-SPIN to two toy protocols and one real world protocol, the CORBA GIOP protocol

Contrast set mining in temporal databases

Understanding the underlying differences between groups or classes in certain contexts can be of the utmost importance. Contrast set mining relies on discovering significant patterns by contrasting two or more groups. A contrast set is a conjunction of attribute–value pairs that differ meaningfully in its distribution across groups. A previously proposed technique is rules for contrast sets, which seeks to express each contrast set found in terms of rules. This work extends rules for contrast sets to a temporal data mining task. We define a set of temporal patterns in order to capture the significant changes in the contrasts discovered along the considered time line. To evaluate the proposal accuracy and ability to discover relevant information, two different real-life data sets were studied using this approach.(undefined

QuantUM: Quantitative Safety Analysis of UML Models

When developing a safety-critical system it is essential to obtain an assessment of different design alternatives. In particular, an early safety assessment of the architectural design of a system is desirable. In spite of the plethora of available formal quantitative analysis methods it is still difficult for software and system architects to integrate these techniques into their every day work. This is mainly due to the lack of methods that can be directly applied to architecture level models, for instance given as UML diagrams. Also, it is necessary that the description methods used do not require a profound knowledge of formal methods. Our approach bridges this gap and improves the integration of quantitative safety analysis methods into the development process. All inputs of the analysis are specified at the level of a UML model. This model is then automatically translated into the analysis model, and the results of the analysis are consequently represented on the level of the UML model. Thus the analysis model and the formal methods used during the analysis are hidden from the user. We illustrate the usefulness of our approach using an industrial strength case study.Comment: In Proceedings QAPL 2011, arXiv:1107.074

The Economics of Globalization: Migration, Trade, and Investment

Die drei wirtschaftlichen Triebkräfte der Globalisierung sind der freie Fluss von Arbeit, Waren und Kapital. Zusammen haben sie in den letzten 200 Jahren drei Wellen der Globalisierung geprägt. Diese Dissertation umfasst alle drei Wellen der Globalisierung zwischen 1877 und 2020 und untersucht ihre drei wichtigsten wirtschaftlichen Faktoren: internationale Migration, Handel und Investitionen. Jedes Kapitel liefert neue Erkenntnisse zu jeweils einem der drei Faktoren. Die Kapitel 1 und 2 liefern neue und kausale Lösungen für offene Fragen zum grundlegenden Verständnis von Migration und internationalem Handel, indem sie zwei natürliche Langzeitexperimente nutzen. Kapitel 1 trägt zum grundlegenden Verständnis der kausalen Wirkung von Einkommensschocks auf Migration im Kontext von wirtschaftlicher Entwicklung bei. Kapitel 2 befasst sich mit dem Distanzpuzzle im internationalen Handel. Kapitel 3 untersucht die Rolle von politischen Beziehungen bei chinesischen Exporten von kritischen medizinischen Gütern während der COVID-19-Pandemie. In Kapitel 4 werden die wirtschaftlichen Auswirkungen des jährlichen Treffens des Weltwirtschaftsforums in Davos analysiert. Diese Dissertation eröffnet zudem durch empirische Kausalforschung neue Perspektiven auf alle drei Wirtschaftsfaktoren der Globalisierung. Sie stellt vier räumlich und zeitlich detaillierte Datensätze vor, die durch quasi-experimentelle Methoden die Grundlage für neue Erkenntnisse über den Themenkomplex der Globalisierung ermöglichen.The three economic drivers of globalization are the free flow of labor, goods, and capital. Together they have shaped three waves of globalization over the last 200 years. This dissertation encompasses all three waves of globalization between 1877 and 2020, and it investigates its three main economic drivers: International migration, trade, and investment. Every chapter brings forward new insights to each of the three drivers separately. Chapters 1 and 2 provide novel and causal solutions to open questions to our fundamental understanding of migration and international trade, by exploiting two natural experiments over the long run. Chapter 1 contributes to the fundamental understanding of the causal effect of income on migration in the context of economic development. Chapter 2 revisits the \textit{distance puzzle} in international trade. Chapter 3 examines the role of politics in Chinese exports of critical medical goods during the COVID-19 pandemic. Finally, Chapter 4 evaluates the economic impact of the annual meeting of the World Economic Forum in Davos, Switzerland. This dissertation further aims to provide new perspectives to all three economic drivers through causal empirical research. It introduces four spatially and temporally granular datasets that provide the foundation of novel insights to the globalization nexus through quasi-experimental methods.2024-12-0

Unit-weighted scales imply models that should be tested!

In several studies unit-weighted sum scales based on the unweighted sum of items are derived from the pattern of salient loadings in confirmatory factor analysis. The problem of this procedure is that the unit-weighted sum scales imply a model other than the initially tested confirmatory factor model. In consequence, it remains generally unknown how well the model implied by the unit-weighted sum scales fits the data. Nevertheless, the derived unit-weighted sum scales are often used in applied settings. The paper demonstrates how model parameters for the unit-weighted sum scales can be computed and tested by means of structural equation modeling. An empirical example based on a personality questionnaire and subsequent unit-weighted scale analyses are presented in order to demonstrate the procedure. Accessed 6,132 times on https://pareonline.net from February 18, 2013 to December 31, 2019. For downloads from January 1, 2020 forward, please click on the PlumX Metrics link to the right

Counterexample-Guided Repair of Reinforcement Learning Systems Using Safety Critics

Naively trained Deep Reinforcement Learning agents may fail to satisfy vital safety constraints. To avoid costly retraining, we may desire to repair a previously trained reinforcement learning agent to obviate unsafe behaviour. We devise a counterexample-guided repair algorithm for repairing reinforcement learning systems leveraging safety critics. The algorithm jointly repairs a reinforcement learning agent and a safety critic using gradient-based constrained optimisation.Comment: 7 pages + reference

Medically Unexplained Oropharyngeal Dysphagia at the University Hospital ENT Outpatient Clinic for Dysphagia: A Cross-Sectional Cohort Study

Medically unexplained oropharyngeal dysphagia (MUNOD) is a rare condition. It presents without demonstrable abnormalities in the anatomy of the upper aero-digestive tract and/or swallowing physiology. This study investigates whether MUNOD is related to affective or other psychiatric conditions. The study included patients with dysphagic complaints who had no detectible structural or physiological abnormalities upon swallowing examination. Patients with any underlying disease or disorder that could explain the oropharyngeal dysphagia were excluded. All patients underwent a standardized examination protocol, with FEES examination, the Hospital Anxiety and Depression Scale (HADS), and the Dysphagia Severity Scale (DSS). Two blinded judges scored five different FEES variables. None of the 14 patients included in this study showed any structural or physiological abnormalities during FEES examination. However, the majority did show abnormal piecemeal deglutition, which could be a symptom of MUNOD. Six patients (42.8%) had clinically relevant symptoms of anxiety and/or depression. The DSS scores did not differ significantly between patients with and without affective symptoms. Affective symptoms are common in patients with MUNOD, and their psychiatric conditions could possibly be related to their swallowing problems

Global inventory of nitrogen oxide emissions constrained by space-based observations of NO2 columns

sions (37.7 Tg N yr #1 ) agrees closely with the GEIAbased a priori (36.4) and with the EDGAR 3.0 bottom-up inventory (36.6), but there are significant regional differences. A posteriori NO x emissions are higher by 50 -- 100% in the Po Valley, Tehran, and Riyadh urban areas, and by 25 -- 35% in Japan and South Africa. Biomass burning emissions from India, central Africa, and Brazil are lower by up to 50%; soil NO x emissions are appreciably higher in the western United States, the Sahel, and southern Europe