A highly efficient multi-core algorithm for clustering extremely large datasets

<p>Abstract</p> <p>Background</p> <p>In recent years, the demand for computational power in computational biology has increased due to rapidly growing data sets from microarray and other high-throughput technologies. This demand is likely to increase. Standard algorithms for analyzing data, such as cluster algorithms, need to be parallelized for fast processing. Unfortunately, most approaches for parallelizing algorithms largely rely on network communication protocols connecting and requiring multiple computers. One answer to this problem is to utilize the intrinsic capabilities in current multi-core hardware to distribute the tasks among the different cores of one computer.</p> <p>Results</p> <p>We introduce a multi-core parallelization of the k-means and k-modes cluster algorithms based on the design principles of transactional memory for clustering gene expression microarray type data and categorial SNP data. Our new shared memory parallel algorithms show to be highly efficient. We demonstrate their computational power and show their utility in cluster stability and sensitivity analysis employing repeated runs with slightly changed parameters. Computation speed of our Java based algorithm was increased by a factor of 10 for large data sets while preserving computational accuracy compared to single-core implementations and a recently published network based parallelization.</p> <p>Conclusions</p> <p>Most desktop computers and even notebooks provide at least dual-core processors. Our multi-core algorithms show that using modern algorithmic concepts, parallelization makes it possible to perform even such laborious tasks as cluster sensitivity and cluster number estimation on the laboratory computer.</p

Search for dark matter produced in association with bottom or top quarks in √s = 13 TeV pp collisions with the ATLAS detector

A search for weakly interacting massive particle dark matter produced in association with bottom or top quarks is presented. Final states containing third-generation quarks and miss- ing transverse momentum are considered. The analysis uses 36.1 fb−1 of proton–proton collision data recorded by the ATLAS experiment at √s = 13 TeV in 2015 and 2016. No significant excess of events above the estimated backgrounds is observed. The results are in- terpreted in the framework of simplified models of spin-0 dark-matter mediators. For colour- neutral spin-0 mediators produced in association with top quarks and decaying into a pair of dark-matter particles, mediator masses below 50 GeV are excluded assuming a dark-matter candidate mass of 1 GeV and unitary couplings. For scalar and pseudoscalar mediators produced in association with bottom quarks, the search sets limits on the production cross- section of 300 times the predicted rate for mediators with masses between 10 and 50 GeV and assuming a dark-matter mass of 1 GeV and unitary coupling. Constraints on colour- charged scalar simplified models are also presented. Assuming a dark-matter particle mass of 35 GeV, mediator particles with mass below 1.1 TeV are excluded for couplings yielding a dark-matter relic density consistent with measurements

Inequality of Chances and Segregation: A Proposed Method of Decomposing Variation through Time in Opportunity Structures

Die vorliegende Arbeit diskutiert die wichtigsten der bislang in der Forschung verwandten Verfahren mit Hilfe des Dissimilaritätsindex Phänomene der Chancengleichheit bzw. Segregation zu messen und in ihrer zeitlichen Veränderung zu bestimmen. Aus der Kritik am Ungenügen dieser Ansätze wird ein neues, auf dem allgemeinen log-linearen Modell basierendes Verfahren zur Zerlegung des Dissimiliritätsindex entwickelt. Dies teilt die Veränderung des Dissimilaritätsindex in der Zeit in zwei Komponenten: eine einzig durch den Strukturwandel der betrachteten Ungleichheitsdimension zwischen zwei Zeitpunkten bedingte Veränderungskomponente (Struktureffekt) und einen Teil (Interaktionseffekt), der davon unabhängig Reduzierung oder Vergrößerung von Chancenungleichheit im engeren Sinn erfaßt. Die Nachteile der bislang verwandten Verfahren wie die Vorteile der neuen Methode werden an Hand einer Untersuchung der Veränderung der geschlechtsspezifischen Bildungschancen der 28-30 Jährigen im Zeitraum zwischen 1950 und 1982 dargestellt.

Jahresbericht 1983 des Forschungsprojektes 'Vergleichende Analysen der Sozialstruktur mit Massendaten'

UuStB Koeln(38)-8406293 / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekSIGLEDEGerman

Changes in Social Structure and the Integration of World War II Refugees

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Ethnic Inequalities in the German School System

On the basis of previous research, the degree and nature of the disadvantages faced by immigrant minorities in the school system of the Federal Republic of Germany remain uncertain. We address these issues by the analysis of two major data sets: the Microcensus of 1989 and the Socio-Economic Panel. Our analysis of the Microcensus reveals the extent of ethnic disadvantage remaining after the socio-economic origins and generational status of students are taken into account. The findings show that children from three groups, Italians, Turks, and Yugoslavs, are more likely than German children to be placed in the least desirable track of the school system, the Hauptschulen, and to leave the system without an apprenticeship (i.e., without a Lehre). Greek children, by contrast, are more likely even than Germans to be found in the most desirable track, the Gymnasium, which feeds into the higher educational system. Our analysis of the Socio-Economic Panel indicates that these ethnic disadvantages are associated with the cultural climate at home and with whether or not the student has had a continuous educational career in Germany. In closing, we discuss these findings in terms of theories about the nature of ethnic disadvantage