15,610 research outputs found

    Deductive Verification of Unmodified Linux Kernel Library Functions

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    This paper presents results from the development and evaluation of a deductive verification benchmark consisting of 26 unmodified Linux kernel library functions implementing conventional memory and string operations. The formal contract of the functions was extracted from their source code and was represented in the form of preconditions and postconditions. The correctness of 23 functions was completely proved using AstraVer toolset, although success for 11 functions was achieved using 2 new specification language constructs. Another 2 functions were proved after a minor modification of their source code, while the final one cannot be completely proved using the existing memory model. The benchmark can be used for the testing and evaluation of deductive verification tools and as a starting point for verifying other parts of the Linux kernel.Comment: 18 pages, 2 tables, 6 listings. Accepted to ISoLA 2018 conference. Evaluating Tools for Software Verification trac

    Miraculous Survival of Three Trapping Miners by Drinking High Mineral Mine Water for 25

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    Little is known that how long a human been can survive a complete starvation. There were dozens of miners who lost their lives in a coal mine disaster at Qinglong,Guizhou,China in June 2009, only three of them were rescued 25 days later after they had been trapped in a coal mine 600 meters underground. They maintained their lives only by drinking mineral water in the mine, which created a miracle of life. We reported here on this life miracle in relation to high mineral mine water

    Use of low-energy hydrogen ion implants in high-efficiency crystalline-silicon solar cells

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    The use of low-energy hydrogen implants in the fabrication of high-efficiency crystalline silicon solar cells was investigated. Low-energy hydrogen implants result in hydrogen-caused effects in all three regions of a solar cell: emitter, space charge region, and base. In web, Czochralski (Cz), and floating zone (Fz) material, low-energy hydrogen implants reduced surface recombination velocity. In all three, the implants passivated the space charge region recombination centers. It was established that hydrogen implants can alter the diffusion properties of ion-implanted boron in silicon, but not ion-implated arsenic

    A Telescoping method for Double Summations

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    We present a method to prove hypergeometric double summation identities. Given a hypergeometric term F(n,i,j)F(n,i,j), we aim to find a difference operator L=a0(n)N0+a1(n)N1+...+ar(n)Nr L=a_0(n) N^0 + a_1(n) N^1 +...+a_r(n) N^r and rational functions R1(n,i,j),R2(n,i,j)R_1(n,i,j),R_2(n,i,j) such that LF=Δi(R1F)+Δj(R2F) L F = \Delta_i (R_1 F) + \Delta_j (R_2 F). Based on simple divisibility considerations, we show that the denominators of R1R_1 and R2R_2 must possess certain factors which can be computed from F(n,i,j)F(n, i,j). Using these factors as estimates, we may find the numerators of R1R_1 and R2R_2 by guessing the upper bounds of the degrees and solving systems of linear equations. Our method is valid for the Andrews-Paule identity, Carlitz's identities, the Ap\'ery-Schmidt-Strehl identity, the Graham-Knuth-Patashnik identity, and the Petkov\v{s}ek-Wilf-Zeilberger identity.Comment: 22 pages. to appear in J. Computational and Applied Mathematic

    Applicability of the qq-Analogue of Zeilberger's Algorithm

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    The applicability or terminating condition for the ordinary case of Zeilberger's algorithm was recently obtained by Abramov. For the qq-analogue, the question of whether a bivariate qq-hypergeometric term has a qZqZ-pair remains open. Le has found a solution to this problem when the given bivariate qq-hypergeometric term is a rational function in certain powers of qq. We solve the problem for the general case by giving a characterization of bivariate qq-hypergeometric terms for which the qq-analogue of Zeilberger's algorithm terminates. Moreover, we give an algorithm to determine whether a bivariate qq-hypergeometric term has a qZqZ-pair.Comment: 15 page

    AMPHIBIAN DISTRIBUTION IN THE GEORGIA SEA ISLANDS: IMPLICATIONS FROM THE PAST AND FOR THE FUTURE

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    We summarized amphibian distributions for 12 coastal islands in Georgia, USA. Occurrence among islands was correlated with life history traits, habitats, island size, distance to other islands, and island geological age. Species’ distributions were determined from published literature. Island sizes and vegetation types were derived from 2011 Georgia Department of Natural Resources habitat maps, which included both federal and state vegetation classification systems. Species occurring on more islands tended to have greater total reproductive output (i.e., life span >4 years, and annual egg production >1,000 eggs) and adults had tolerance of brackish environs. Larger islands had great­er area of freshwater wetlands, predominantly short hydroperiod (<6 months). Species tied to long hydroperiod wetlands (>6 months) were more restricted in their distribution across islands. Overall, larger islands supported more species, but the correlation was weaker for geologically younger Ho­locene islands (age <11,000 years). While Euclidean distance between islands does not necessarily preclude inter-island dispersal, inhospitable habitat for amphibians (brackish tidal marshes and creeks interspersed with wide rivers) suggests that inter-island dispersal is very limited. The paucity of recent occurrence data for amphibians in this dynamic coastal region, let alone standardized annual moni­toring data, hinders efforts to model species’ vulnerability in a region susceptible to sea level rise and development pressure. The most common survey method, standardized amphibian vocal surveys, will detect Anuran reproductive efforts, but is unlikely to ascertain if breeding was successful or to detect salamanders. While it will not replace actual population data, consideration of critical life-history traits and breeding habitat availability can be used to direct management to support long-term species per­sistence in changing environs. Even common amphibians in coastal conservation areas of Georgia are vulnerable to increasing population isolation caused by unsuitable habitat

    Higgs Triplets, Decoupling, and Precision Measurements

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    Electroweak precision data has been extensively used to constrain models containing physics beyond that of the Standard Model. When the model contains Higgs scalars in representations other than SU(2) singlets or doublets, and hence rho not equal to one at tree level, a correct renormalization scheme requires more inputs than the three needed for the Standard Model. We discuss the connection between the renormalization of models with Higgs triplets and the decoupling properties of the models as the mass scale for the scalar triplet field becomes much larger than the electroweak scale. The requirements of perturbativity of the couplings and agreement with electroweak data place strong restrictions on models with Higgs triplets. Our results have important implications for Little Higgs type models and other models with rho not equal to one at tree level.Comment: 23 page
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