On the Runtime Dynamics of the Univariate Marginal Distribution Algorithm on Jump Functions

University of Minnesota M.S. thesis. May 2018. Major: Computer Science. Advisor: Andrew Sutton. 1 computer file (PDF); vi, 79 pages.Solving jump functions by using traditional evolutionary algorithms (EAs) seems to be a challenging task. Mutation only EAs have a hard time flipping the right number of bits to generate the optimum. To optimize a jump function, an algorithm must be able to execute an initial hill-climbing phase, after which a point across a large gap must be generated. We study a family of EAs called estimation of distribution algorithms (EDAs) which works differently than standard EAs. In EDAs, we do not store the actual bitstrings, but rather a probability distribution that is initially uniform and should evolve to a model that always generates the global optimum. We study an EDA called Univariate Marginal Distribution Algorithm (UMDA) and analyze it on jump functions with gap k. We show experimental work on runtimes and probability of succeeding to solve the jump function for different values of k. We take an innovative approach and modify the UMDA by turning off selection. For this new algorithm we present a formal analyses in which, if certain conditions are met, we prove an upper bound on generating the optimum all 1s bistring. Lastly, we compare our results with a different EDA called the compact Genetic Algorithm (cGA) analyzing the jump function. We mention pros and cons of both algorithms under different scenarios

Identification of CRISPR and riboswitch related RNAs among novel noncoding RNAs of the euryarchaeon Pyrococcus abyssi

<p>Abstract</p> <p>Background</p> <p>Noncoding RNA (ncRNA) has been recognized as an important regulator of gene expression networks in Bacteria and Eucaryota. Little is known about ncRNA in thermococcal archaea except for the eukaryotic-like C/D and H/ACA modification guide RNAs.</p> <p>Results</p> <p>Using a combination of <it>in silico </it>and experimental approaches, we identified and characterized novel <it>P</it>. <it>abyssi </it>ncRNAs transcribed from 12 intergenic regions, ten of which are conserved throughout the Thermococcales. Several of them accumulate in the late-exponential phase of growth. Analysis of the genomic context and sequence conservation amongst related thermococcal species revealed two novel <it>P</it>. <it>abyssi </it>ncRNA families. The CRISPR family is comprised of crRNAs expressed from two of the four <it>P</it>. <it>abyssi </it>CRISPR cassettes. The 5'UTR derived family includes four conserved ncRNAs, two of which have features similar to known bacterial riboswitches. Several of the novel ncRNAs have sequence similarities to orphan OrfB transposase elements. Based on RNA secondary structure predictions and experimental results, we show that three of the twelve ncRNAs include Kink-turn RNA motifs, arguing for a biological role of these ncRNAs in the cell. Furthermore, our results show that several of the ncRNAs are subjected to processing events by enzymes that remain to be identified and characterized.</p> <p>Conclusions</p> <p>This work proposes a revised annotation of CRISPR loci in <it>P</it>. <it>abyssi </it>and expands our knowledge of ncRNAs in the Thermococcales, thus providing a starting point for studies needed to elucidate their biological function.</p

Larry Miles--Ein Leben Fur Die Wertanalyse

Article in German language. Magazine from Austria

Wissenschaftliche Abhandlungen

The Austrian physicist Ludwig Eduard Boltzmann (1844-1906), educated at the University of Vienna, was appointed professor of mathematical physics at the University of Graz in 1869 at the age of only twenty-five. Boltzmann did important work in the fields of statistical mechanics and statistical thermodynamics; for instance, he contributed to the kinetic theory concerned with molecular speeds in gas. Boltzmann also promoted atomic theory, which at the time was still highly controversial. He was a member of the Imperial Austrian Academy of Sciences from 1885 and became a member of the Royal Swedish Academy of Sciences in 1888. This three-volume work, prepared in 1909 by the physicist Fritz Hasenöhrl, one of Boltzmann's students, comprises all his academic publications from 1865 to 1905

NSOM Lithography for Organized Growth of Gap Nanowires

In this contribution, near field scanning optical microscope (NSOM) lithography is presented as a tool for organized growth of nanowires. Non contact mode of NSOM lithography was used to pattern planar structures in photoresist deposited on GaP substrate. In combination with lift-off technique, metal-catalyst particles on GaP substrate for subsequent growth of GaP nanowires were prepared. Different periodic and predefined arrangements of GaP nanowires were achieved

Growth evolution of N-polar indium-rich InAlN layer on c-sapphire via strain relaxation by ultrathin AlON interlayer

status: publishe

Evidence of relationship between strain and In-incorporation: Growth of N-polar In-rich InAlN buffer layer by OMCVD

© 2019 Author(s). Two I n x A l 1 - x N layers were grown simultaneously on different substrates [sapphire (0001) and the Ga-polar GaN template], but under the same reactor conditions, they were employed to investigate the mechanism of strain-driven compositional evolution. The resulting layers on different substrates exhibit different polarities and the layer grown on sapphire is N-polar. Moreover, for the two substrates, the difference in the degree of relaxation of the grown layers was almost 100%, leading to a large In-molar fraction difference of 0.32. Incorporation of In in I n x A l 1 - x N layers was found to be significantly influenced by the strain imposed by the under-layers. With the evolutionary process of In-incorporation during subsequent layer growth along [0001], the direction of growth was investigated in detail by Auger electron spectroscopy. It is discovered that the I n 0.60 A l 0.40 N layer grown directly on sapphire consists of two different regions with different molar fractions: the transition region and the uniform region. According to the detailed cross-sectional transmission electron microscopy, the transition region is formed near the hetero-interface due to the partial strain release caused by the generation of misfit-dislocations. The magnitude of residual strain in the uniform region decides the In-molar fraction. I n x A l 1 - x N layers were analyzed by structural and optical characterization techniques. Our present work also shows that a multi-characterization approach to study I n x A l 1 - x N is a prerequisite for their applications as a buffer layer.status: publishe