1,135 research outputs found

    Brotli: A General-Purpose Data Compressor

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    Brotli is an open source general-purpose data compressor introduced by Google in late 2013 and now adopted in most known browsers and Web servers. It is publicly available on GitHub and its data format was submitted as RFC 7932 in July 2016. Brotli is based on the Lempel-Ziv compression scheme and planned as a generic replacement of Gzip and ZLib. The main goal in its design was to compress data on the Internet, which meant optimizing the resources used at decoding time, while achieving maximal compression density. This article is intended to provide the first thorough, systematic description of the Brotli format as well as a detailed computational and experimental analysis of the main algorithmic blocks underlying the current encoder implementation, together with a comparison against compressors of different families constituting the state-of-the-art either in practice or in theory. This treatment will allow us to raise a set of new algorithmic and software engineering problems that deserve further attention from the scientific community

    Cargo/Logistics Airlift System Study (CLASS), Volume 2

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    Air containerization is discussed in terms of lower freight rates, size and pallet limitations, refrigeration, backhaul of empties, and ownership. It is concluded that there is a need for an advance air cargo system as indicated by the industry/transportation case studies, and a stimulation of the air cargo would result in freight rate reductions

    Textile production in nineteenth century Orange, Alamance, and Durham counties, North Carolina

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    The purpose of this study was to investigate domestic textile production in nineteenth century Orange, Alamance, and Durham counties, North Carolina. The specific objectives were to determine the amount of home textile production, the effect of the textile mill industry on home production, and the role of men and/or women in domestic textile production. Public records have proven to be reliable sources about material culture. These records often include references to textile production equipment and are a reliable means of learning about textile production practices. Content analysis was done of all the nineteenth century estate records and wills available in the three counties. The records included documents such as estate inventories, sales accounts, widows' allotments, guardians' accounts, bills from craftsmen, and merchants accounts. This information was recorded for each record: date (usually of death), name of the decedent, type of document in the estate records, piece of equipment, and price. The chi square statistical text was done to compare equipment ownership of men and of women. Extant handwoven bedcoverings were analyzed and the oral history recorded

    An extensive English language bibliography on graph theory and its applications

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    Bibliography on graph theory and its application

    Geographic Concentration in U.S. Manufacturing Industries: A Dartboard Approach

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    This paper discusses the prevalence of Silicon Valley-style localizations of individual manufacturing industries in the United States. Several models in which firms choose locations by throwing darts at a map are used to test whether the degree of localization is greater than would be expected to arise randomly and to motivate a new index of geographic concentration. The proposed index controls for differences in the size distribution of plants and for differences in the size of the geographic areas for which data is available. As a consequence, comparisons of the degree of geographic concentration across industries can be made with more confidence. We reaffirm previous observations in finding that almost all industries are localized, although the degree of localization appears to be slight in about half of the industries in our sample. We explore the nature of agglomerative forces in describing patterns of concentration, the geographic scope of localization, and the extent to which agglomerations involve plants in similar as opposed to identical industries.

    Triangulations

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    The earliest work in topology was often based on explicit combinatorial models – usually triangulations – for the spaces being studied. Although algebraic methods in topology gradually replaced combinatorial ones in the mid-1900s, the emergence of computers later revitalized the study of triangulations. By now there are several distinct mathematical communities actively doing work on different aspects of triangulations. The goal of this workshop was to bring the researchers from these various communities together to stimulate interaction and to benefit from the exchange of ideas and methods

    New methods for finding minimum genus embeddings of graphs on orientable and non-orientable surfaces

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    The question of how to find the smallest genus of all embeddings of a given finite connected graph on an orientable (or non-orientable) surface has a long and interesting history. In this paper we introduce four new approaches to help answer this question, in both the orientable and non-orientable cases. One approach involves taking orbits of subgroups of the automorphism group on cycles of particular lengths in the graph as candidates for subsets of the faces of an embedding. Another uses properties of an auxiliary graph defined in terms of compatibility of these cycles. We also present two methods that make use of integer linear programming, to help determine bounds for the minimum genus, and to find minimum genus embeddings. This work was motivated by the problem of finding the minimum genus of the Hoffman-Singleton graph, and succeeded not only in solving that problem but also in answering several other open questions

    Unraveling the Genetic Mysteries of the Norwegian Fjord-horse: Identifying Harmful Haplotypes for Improved Breeding Strategies

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    Fertiliteten til avlsdyrene er særdeles kritisk i små populasjoner med høy innavl. Fjordhest- populasjonen i Norge består av få stamfedre, og er blitt registrert til å ha en lavere føllings-rate enn flere andre hesteraser. Denne analysen er basert på høy-tetthets SNP genotyper fra ca. 330 Fjordhester. For å identifisere mulige resessive dødelige alleler undersøkes genomet for homozygote avvik i haplotyper. Signifikante avvik i haplotyper med én eller mindre observerte homozygoter ble karakterisert som kandidat-loci. Deretter, vil kandidat-loci analyseres i forhold til funksjonell kunnskap om genomet til hest, menneske og mus. Kandidatgenene som dette studiet kommer frem til er DEAF5L, DEFA22, KIA1109, og DPF2.The fertility in breeding-animals is especially critical in small populations in which there is a high degree of inbreeding. The Norwegian Fjord-horse population consists of few founder animals and is observed to underperform in foaling rate compared to several other horse breeds. The project is based on HD SNP genotypes from approximately 330 Fjord-horses. In order to identify potential recessive lethal alleles, the haplotype homozygote deficiencies were identified. Significant haplotypes with one or fewer homozygotes observed were characterized as the candidate loci. Further, the candidate loci were aligned with functional knowledge of equine, human, and mouse genomes. Candidate genes identified by this study were DEFA5L, DEFA22, KIA1109, and DPF2
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