An Efficient Rigorous Approach for Identifying Statistically Significant Frequent Itemsets

As advances in technology allow for the collection, storage, and analysis of vast amounts of data, the task of screening and assessing the significance of discovered patterns is becoming a major challenge in data mining applications. In this work, we address significance in the context of frequent itemset mining. Specifically, we develop a novel methodology to identify a meaningful support threshold s* for a dataset, such that the number of itemsets with support at least s* represents a substantial deviation from what would be expected in a random dataset with the same number of transactions and the same individual item frequencies. These itemsets can then be flagged as statistically significant with a small false discovery rate. We present extensive experimental results to substantiate the effectiveness of our methodology.Comment: A preliminary version of this work was presented in ACM PODS 2009. 20 pages, 0 figure

Multiferroic bismuth ferrates : Synthesis, structure-property relationships and phase transformations

Nowadays, great efforts are made to understand the rich physics of materials that show interesting magnetic, electronic, optic, photocatalytic or even multiferroic properties. Within the scope of this dissertation two of such potentially very promising compounds, perovskite-type (Bi1-xFex)FeO3 and mullite-type Bi2Fe4O9, were synthesized and studied. The primary focus was placed to understand the synthesis conditions that strongly influence the resulting phase composition, structures and corresponding properties. The second main focus was to study the structure-property relationships based on the average crystallite size, chemical composition and phase composition of the materials. It could be shown that the phase system Bi2O3 - Fe2O3 is very complex and sensitive to a lot of synthesis parameters such as the type of complexing agent, pH value as well as calcination time and temperature

Search for the neutrinoless double beta-decay in Gerda Phase I using a Pulse Shape Discrimination technique

The Germanium Detector Array (Gerda) experiment, located underground at the INFN Laboratori Nazionali del Gran Sasso (LNGS) in Italy, deploys high-purity germanium detectors to search for the neutrinoless double beta-decay (0vbb) of 76Ge. An observation of this lepton number violating process, which is expected by many extensions of the Standard Model, would not only generate a fundamental shift in our understanding of particle physics, but also unambiguously prove the neutrino to have a non-vanishing Majorana mass component. A first phase of data recording lasted from November 2011 to May 2013 - resulting in a total exposure (defined as the product of detector mass and measurement time) of 21.6 kg*yr. Within this thesis a thorough study of this data with special emphasis on the development and scrutiny of an active background suppression technique by means of a signal shape analysis has been performed. Among several investigated multivariate approaches, particularly a selection algorithm based on an artificial neural network is found to yield the best performance; i.a. the background index close to the Q-value of the 0vbb- decay could be suppressed by 45% to 1*10^(-2) cts/(keV*kg*yr), while still retaining a considerably high signal survival fraction of (83+/-3)% leading to a significant improvement of the experimental sensitivity. The efficiency is derived by a simulation and further validated by substantiated consistency checks availing themselves of measurements taken with different calibration sources and physics data. No signal is observed and a new lower limit of T(90%C.L.)>2.2*10^25 yr for the half-life of neutrinoless double beta-decay of 76Ge is established

Copeptin als Indikator für osmotische Belastung bei erhöhtem Blutzucker während des oralen Glukose-Toleranztestes

Die vorliegende Studie liefert anhand der im Zeitraum von Juni 2016 bis März 2018 erhobenen Daten wichtige Informationen über die Zusammenhänge zwischen Hyperglykämie, osmotischer Belastung und Volumenregulation. In der Auswertung konnten sowohl bereits bekannte als auch neue Korrelationen in Bezug auf Blutzuckerstoffwechselstörungen und deren physiologische Auswirkung gefunden werden. Die Ergebnisse dieser Studie wurden im Juli 2020 unter dem Titel »Diabetes mellitus and hypertension - a case of sugar and salt« im International Journal of Molecular Sciences 2020 veröffentlicht.The presented study provides important information on the correlations between hyperglycemia, osmotic load, and volume regulation using data collected from June 2016 to March 2018. In the analysis, both already known and new correlations related to blood glucose metabolic disturbances and their physiological impact could be found. The results of this study were published in the International Journal of Molecular Sciences 2020 in July 2020 under the title "Diabetes mellitus and hypertension - a case of sugar and salt"

PER-MARE: Adaptive Deployment of MapReduce over Pervasive Grids

International audienceMapReduce is a parallel programming paradigm successfully used to perform computations on massive amounts of data, being widely deployed on clusters, grid, and cloud infrastructures. Interestingly, while the emergence of cloud in- frastructures has opened new perspectives, several enterprises hesitate to put sensible data on the cloud and prefer to rely on internal resources. In this paper we introduce the PER- MARE initiative, which aims at proposing scalable techniques to support existent MapReduce data-intensive applications in the context of loosely coupled networks such as pervasive and desktop grids. By relying on the MapReduce programming model, PER-MARE proposes to explore the potential advan- tages of using free unused resources available at enterprises as pervasive grids, alone or in a hybrid environment. This paper presents the main lines that orient the PER-MARE approach and some preliminary results

MAPREDUCE CHALLENGES ON PERVASIVE GRIDS

International audienceThis study presents the advances on designing and implementing scalable techniques to support the development and execution of MapReduce application in pervasive distributed computing infrastructures, in the context of the PER-MARE project. A pervasive framework for MapReduce applications is very useful in practice, especially in those scientific, enterprises and educational centers which have many unused or underused computing resources, which can be fully exploited to solve relevant problems that demand large computing power, such as scientific computing applications, big data processing, etc. In this study, we pro-pose the study of multiple techniques to support volatility and heterogeneity on MapReduce, by applying two complementary approaches: Improving the Apache Hadoop middleware by including context-awareness and fault-tolerance features; and providing an alternative pervasive grid implementation, fully adapted to dynamic environments. The main design and implementation decisions for both alternatives are described and validated through experiments, demonstrating that our approaches provide high reliability when executing on pervasive environments. The analysis of the experiments also leads to several insights on the requirements and constraints from dynamic and volatile systems, reinforcing the importance of context-aware information and advanced fault-tolerance features to provide efficient and reliable MapReduce services on pervasive grids

Comparison of different noise sources for the simulative cabin noise assessment of an electrically propelled regional aircraft

The rising number of passengers transported by aircraft leads to more flight traffic, further increasing the environmental impact of the aviation sector. In order to combat the growing environmental impact, the Cluster of Excellence Sustainable and Energy Efficient Aviation of TU Braunschweig aims to advance research towards a climate neutral aviation industry, especially with the design of an electrically propelled short-range regional aircraft, among others. In the conscience of passengers, the focus is also shifted towards a healthy and comfortable travel experience. One of the main factors influencing these aspects is noise inside the aircraft cabin. A lower noise impact can help increase the technology acceptance and further push towards more sustainable airborne transport solutions. This contribution aims to simulatively assess and compare the sound pressure levels inside the passenger cabin of an electric propeller aircraft. The focus is laid on two of the most important noise sources: the tonal propeller excitation as well as the sound field beneath the turbulent boundary layer. The paper presents a wave-resolving FE model considering both sources and shows, which sound pressure levels can be expected, while also comparing the frequency spectra separately, therefore enabling early design changes to help reduce the cabin noise

Efeito da administração do citrato de clomifeno durante o período perinatal no comportamento sexual, peso dos órgãos e concentração hormonal de ratos Wistar machos e fêmeas

The effects of prenatal exposure to clomiphene citrate in sexual behavior, organ weight and hormone concentrations of male and female rats was evaluated. The animals received four doses of clomiphene citrate 2 mg/mL each during the prenatal period (21 days of gestation – DG21) on days 1 (DN1), 2 (DN2) and 3 (DN3) after the birth of the puppies. The treatment led to the development of polycystic ovaries in 70% of the females, masculinization of female sexual behavior and changes in sexual behavior of males evidenced by the reduction in the number of ejaculations. In regards to hormone levels, a decrease in the FSH levels in male offspring was observed. It was concluded that clomiphene citrate interferes with the reproductive capacity of male and female rats and female sexual orientation when prenatally administered.Foram investigados os efeitos da exposição perinatal ao citrato de clomifeno no comportamento sexual, peso dos órgãos e concentração hormonal de ratos machos e fêmeas. Os animais receberam quatro doses de 2 mg/mL de citrato de clomifeno, no período perinatal (21 dias de gestação – DG21), nos dias 1 (DN1), 2 (DN2) e 3 (DN3) após o nascimento dos filhotes. O tratamento causou desenvolvimento de ovário policístico em 70% das fêmeas, masculinização do comportamento sexual das fêmeas e alteração do comportamento sexual dos machos evidenciado pela redução no número de ejaculações. Em relação aos níveis hormonais, observou-se diminuição de FSH na prole masculina. Concluiu-se que o citrato de clomifeno interfere na capacidade reprodutiva de ratos machos e fêmeas, e na orientação sexual de fêmeas, quando administrado perinatalmente

Propofol-Induced Frontal Cortex Disconnection: A Study of Resting-State Networks, Total Brain Connectivity, and Mean BOLD Signal Oscillation Frequencies.

Propofol is one of the most commonly used anesthetics in the world, but much remains unknown about the mechanisms by which it induces loss of consciousness. In this resting-state functional magnetic resonance imaging study, we examined qualitative and quantitative changes of resting-state networks (RSNs), total brain connectivity, and mean oscillation frequencies of the regional blood oxygenation level-dependent (BOLD) signal, associated with propofol-induced mild sedation and loss of responsiveness in healthy subjects. We found that detectability of RSNs diminished significantly with loss of responsiveness, and total brain connectivity decreased strongly in the frontal cortex, which was associated with increased mean oscillation frequencies of the BOLD signal. Our results suggest a pivotal role of the frontal cortex in propofol-induced loss of responsiveness

Gleichstellungsimpulse im SGB II Zielsteuerungssystem: Zwischenbericht

Dieser Zwischenbericht stellt erste Ergebnisse aus dem bisherigen Verlauf des Forschungsprojektes "Gleichstellungsimpulse im SGB II Zielsteuerungssystem" dar. Auf Basis eines qualitativen und quantitativen Forschungszugangs wird untersucht, welche steuerungsrelevanten Impulse im Rahmen des besteh­enden bundesweiten Zielsteuerungssystems in der Grundsicherung für Arbeitsuchende gesetzt werden können, damit die Jobcenter und weitere Steuerungsbeteiligte durchgängig das gleichstellungs­politische Ziel verfolgen und in ihrem Handeln zum Ausdruck bringen. Der Zwischenbericht liefert erste Erkenntnisse sowie Ableitungen aus der Literatur- und Dokumentenanalyse, aus Interviews mit Expert*innen sowie aus den Fallstudien an 16 Jobcenter-Standorten