QuickMMCTest - Quick Multiple Monte Carlo Testing

Multiple hypothesis testing is widely used to evaluate scientific studies involving statistical tests. However, for many of these tests, p-values are not available and are thus often approximated using Monte Carlo tests such as permutation tests or bootstrap tests. This article presents a simple algorithm based on Thompson Sampling to test multiple hypotheses. It works with arbitrary multiple testing procedures, in particular with step-up and step-down procedures. Its main feature is to sequentially allocate Monte Carlo effort, generating more Monte Carlo samples for tests whose decisions are so far less certain. A simulation study demonstrates that for a low computational effort, the new approach yields a higher power and a higher degree of reproducibility of its results than previously suggested methods

A Framework for Monte Carlo based Multiple Testing

We are concerned with a situation in which we would like to test multiple hypotheses with tests whose p-values cannot be computed explicitly but can be approximated using Monte Carlo simulation. This scenario occurs widely in practice. We are interested in obtaining the same rejections and non-rejections as the ones obtained if the p-values for all hypotheses had been available. The present article introduces a framework for this scenario by providing a generic algorithm for a general multiple testing procedure. We establish conditions which guarantee that the rejections and non-rejections obtained through Monte Carlo simulations are identical to the ones obtained with the p-values. Our framework is applicable to a general class of step-up and step-down procedures which includes many established multiple testing corrections such as the ones of Bonferroni, Holm, Sidak, Hochberg or Benjamini-Hochberg. Moreover, we show how to use our framework to improve algorithms available in the literature in such a way as to yield theoretical guarantees on their results. These modifications can easily be implemented in practice and lead to a particular way of reporting multiple testing results as three sets together with an error bound on their correctness, demonstrated exemplarily using a real biological dataset

User-Friendly Ontology Creation Methodologies - A Survey

The convergence of the semantic web and the social web to the social semantic web leads to new challenges in ontology engineering. As of today ontologies are created by highly specialized ontology engineers. In order to unite the wisdom of crowds and ontologies new approaches to ontology creation are necessary to bridge the ontology gap and enable novice users to create formalized knowledge. Numerous ontology development methodologies are available; in this paper we will briefly present 16 ontology development methodologies and evaluate them against criteria for their user-friendliness and their suitability for usage by novice users and domain experts. Our eventual goal is the identification of best practices and required research for user-friendly ontology design

Instability of Dielectric Surface Passivation Quality at Elevated Temperature and Illumination

AbstractHydrogenated silicon nitride and aluminum oxide passivation layers were deposited on boron doped floatzone silicon wafers that underwent a high temperature firing step. The passivation quality was monitored during thermal treatment at 75°C, 150°C and 250°C in darkness or under illumination. It was found that the passivation quality of the specific layers under investigation is far from stable in the course of time showing both deterioration and improvement features on a time scale of minutes to weeks. Furthermore, it was found that these changes occur in both darkness and under illumination, whereupon (stronger) illumination accelerates the changes. Via corona charging and capacitance voltage experiments it could be shown that the observed changes in the short term are mainly caused by changes in the chemical passivation quality

Effect of temperature and time after collection on buck sperm quality

Background: Different parameters are assessed as part of the semen analysis but a standard protocol for evaluation of goat semen is still missing. The aim of this study was to analyse two different factors affecting buck sperm quality in the post-collection period prior to adding the extender. Here we examined the effects of two handling temperatures (20 °C, 37 °C) and various examination time points (3-30 min) after semen collection. Results: Examination time point had a significant influence on raw sperm viability (p 0.05), motility (p > 0.05), with the exception of fast moving sperm (p = 0.04), or on semen pH (p > 0.05). Conclusion: Examination time point was identified as factor strongly influencing raw peacock buck semen after collection. Raw goat semen can tolerate room temperatures for at least 10 min without impacting overall semen quality. In order to obtain comparable results, semen samples should always be examined within 10 min after collection

possible lead and/ or mercury intoxication from imported natural health products and a need for scientifically evaluated poisoning monitoring from environmental exposures

Background With increases in globalization, cultural remedies from Chinese, Ayurvedic, Arab and other traditions have become more available to international consumers, offering unfamiliar “Natural Health Products” (NHP), used as alternative medicine or supplementary medicine. Contamination with toxic ingredients including lead, mercury, arsenic, and other toxic elements has been documented in several of these products from various parts of the globe, particularly from some parts of Asia and the Orient. Findings We have been following this development in the last 6 years and have analyzed n = 20 such products (60 analyses) from patients with intoxication symptoms in a pilot study, showing alarming high concentrations of mercury and/or lead (the first one in “therapeutic” doses). 82 % of the studied NHP contained lead concentrations above the EU limit for dietary supplements. 62 % of the samples exceeded the limit values for mercury. Elevated blood lead and mercury levels in patients along with clinical intoxication symptoms corroborate the causal assumption of intoxication (s). We present one detailed clinical case report of severe lead and mercury intoxications and give an overview about blood concentration related symptoms and signs of n = 41 case reports of mercury intoxications of the German monitoring BfR-DocCenter. Conclusions For NHP there is evidence on a distinct toxicological risk with alarming low awareness for a possible intoxication which prevents potentially life-saving diagnostic steps in affected cases. In many cases patients do not communicate the events to their physicians or the local health authority so that case reports (e.g. the BfR-DocCentre) are missing. Thus, there is an urgent need to raise awareness and to initiate more suitable monitory systems (e.g. National Monitoring of Poisonings) and control practice protecting the public

Ad hoc HLA simulation model derived from a model-based traffic scenario

Modern highly automated and autonomous traffic systems and sub-systems require new approaches to test their functional safety in the context of validation and verification. One approach that has taken a leading role in current research is scenario-based testing. For various reasons, simulation is considered to be the most practicable solution for a wide range of test scenarios. However, this is where many existing simulation systems in research reach their limits. In order to be able to integrate the widest possible range of systems to be tested into the simulation, the use of co-simulation has proven to be particularly useful. In this work, the High-Level Architecture defined in the IEEE 1516-2010 standard is specifically addressed, and a concept is developed that establishes the foundation for the feasible use of scenario-based distributed co-simulation on its basis. The main challenge identified and addressed is the resolution of the double-sided dependency between scenario and simulation models. The solution was to fully automate the generation and instantiation of the simulation environment on the basis of a scenario instance. Finally, the developed concept was implemented as a prototype, and the resulting process for its use is presented here using an example scenario. Based on the experience gained during the creation of the concept and the prototype, the next steps for future work are outlined in conclusion

Schema zur Ladeinfrastrukturbewertung für Elektromobilität

Elektromobilität verspricht eine erhöhte Lebensqualität des Nutzers in Hinblick auf emissions- und lärmärmeres Fahren. Diesen Potenzialen stehen jedoch diverse Hürden, wie z.B. kurze Reichweiten und lange Ladezeiten der Fahrzeuge entgegen. Der Aufbau einer flächendeckenden Ladeinfrastruktur zur Überwindung der Hürden wird von zum Teil konkurrierenden Interessengruppen beeinflusst. Um die Planung eines Ladeinfrastrukturlayouts zu unterstützen, existiert bereits ein agentenbasiertes Simulationsframework. Für die Bewertung des Infrastrukturlayouts aus Sicht mehrerer Stakeholder benötigt dieses Framework ein Bewertungsschema, das die Interessen der einzelnen Gruppen quantitativ abbildet. Dieser Beitrag beschreibt die Entwicklung dieses Schemas inkl. dessen Formalisierung unter Zuhilfenahme einer durchgeführten Stakeholderanalyse