1,852 research outputs found

    Empirical evaluation of Pareto efficient multi-objective regression test case prioritisation

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    The aim of test case prioritisation is to determine an ordering of test cases that maximises the likelihood of early fault revelation. Previous prioritisation techniques have tended to be single objective, for which the additional greedy algorithm is the current state-of-the-art. Unlike test suite minimisation, multi objective test case prioritisation has not been thoroughly evaluated. This paper presents an extensive empirical study of the effectiveness of multi objective test case prioritisation, evaluating it on multiple versions of five widely-used benchmark programs and a much larger real world system of over 1 million lines of code. The paper also presents a lossless coverage compaction algorithm that dramatically scales the performance of all algorithms studied by between 2 and 4 orders of magnitude, making prioritisation practical for even very demanding problems. Copyright is held by the owner/author(s)

    RAPTOR USE OF ARTIFICIAL PERCHES AT NATURAL AREAS, CITY OF FORT COLLINS, COLORADO

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    The black-tailed prairie dog (Cynomys ludovicianus) remains a critical element of the prairie ecosystem even though its numbers and occupied range have declined dramatically since the arrival of Europeans in North America (Antol in et al. 2002). Prairie dog colonies are used by many species of wildlife and help maintain high levels of biodiversity (Kotliar et al. 1999). In the urban-suburban setting, the occurrence of prairie dog colonies also provides opportunities for wildlife viewing and environmental education. Unfortunately, prairie dogs also can come into conflict with humans, especially in the urban-suburban setting, where they cause vegetation and property damage, and pose a health threat attributable to periodic plague (Yersinia pestis) outbreaks (Witmer et al. 2003). Efforts to reduce conflicts can involve colony relocation or management so that the prairie dog population and occupied area does not increase (e.g., lethal or non-lethal removal, construction of physical barriers around the colony; Witmer et al. 2003). frtificial perches, placed at prairie dog colonies, can attract raptors, while providing for public viewing of raptors. The artificial perches, if strategically placed, also might increase predation on prairie dogs, slowing the increase in the size of the colony (Witmer et al. 2003). This approach has been used in other settings in an attempt to reduce rodent populations or damage, but most researchers reported little success in rodent control (e.g., Howard et al. 1985, Askham 1990, Moore and Van Vuren 1998, Wolff et al. 1999). A few researchers, however, reported that increased use of artificial perches might help reduce rodent numbers and damage (e.g., Kay et al. 1994, Mulner 2000, Hafidzi and Mohd 2003). In our region, this management practice might be especially effective given the paucity of trees (i.e., natural perches) in the shortgrass prairie outside riparian systems (Weaver et al. 1996). The objective of this study was to document the use of artificial perches by raptors and the food habits of these raptors within the city limits of Fort Collins, Colorado

    RAPTOR USE OF ARTIFICIAL PERCHES AT NATURAL AREAS, CITY OF FORT COLLINS, COLORADO

    Get PDF
    The black-tailed prairie dog (Cynomys ludovicianus) remains a critical element of the prairie ecosystem even though its numbers and occupied range have declined dramatically since the arrival of Europeans in North America (Antol in et al. 2002). Prairie dog colonies are used by many species of wildlife and help maintain high levels of biodiversity (Kotliar et al. 1999). In the urban-suburban setting, the occurrence of prairie dog colonies also provides opportunities for wildlife viewing and environmental education. Unfortunately, prairie dogs also can come into conflict with humans, especially in the urban-suburban setting, where they cause vegetation and property damage, and pose a health threat attributable to periodic plague (Yersinia pestis) outbreaks (Witmer et al. 2003). Efforts to reduce conflicts can involve colony relocation or management so that the prairie dog population and occupied area does not increase (e.g., lethal or non-lethal removal, construction of physical barriers around the colony; Witmer et al. 2003). frtificial perches, placed at prairie dog colonies, can attract raptors, while providing for public viewing of raptors. The artificial perches, if strategically placed, also might increase predation on prairie dogs, slowing the increase in the size of the colony (Witmer et al. 2003). This approach has been used in other settings in an attempt to reduce rodent populations or damage, but most researchers reported little success in rodent control (e.g., Howard et al. 1985, Askham 1990, Moore and Van Vuren 1998, Wolff et al. 1999). A few researchers, however, reported that increased use of artificial perches might help reduce rodent numbers and damage (e.g., Kay et al. 1994, Mulner 2000, Hafidzi and Mohd 2003). In our region, this management practice might be especially effective given the paucity of trees (i.e., natural perches) in the shortgrass prairie outside riparian systems (Weaver et al. 1996). The objective of this study was to document the use of artificial perches by raptors and the food habits of these raptors within the city limits of Fort Collins, Colorado

    A study of elevated temperature testing techniques for the fatigue behavior of PMCS: Application to T650-35/AMB21

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    An experimental study was conducted to investigate the mechanical behavior of a T650-35/AMB21 eight-harness satin weave polymer composite system. Emphasis was placed on the development and refinement of techniques used in elevated temperature uniaxial PMC testing. Issues such as specimen design, gripping, strain measurement, and temperature control and measurement were addressed. Quasi-static tensile and fatigue properties (R(sub sigma) = 0.1) were examined at room and elevated temperatures. Stiffness degradation and strain accumulation during fatigue cycling were recorded to monitor damage progression and provide insight for future analytical modeling efforts. Accomplishments included an untabbed dog-bone specimen design which consistently failed in the gage section, accurate temperature control and assessment, and continuous in-situ strain measurement capability during fatigue loading at elevated temperatures. Finally, strain accumulation and stiffness degradation during fatigue cycling appeared to be good indicators of damage progression

    Formation and structural chemistry of the unusual cyanide-bridged dinuclear species [Ru-2(NN)(2)(CN)(7)](3-)(NN=2,2 '-bipyridine or 1,10-phenanthroline)

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    Crystallisation of simple cyanoruthenate complex anions [Ru(NN)(CN)(4)](2) (NN = 2,2'-bipyridine or 1,10-phenanthroline) in the presence of Lewis-acidic cations such as Ln(III) or guanidinium cations results, in addition to the expected [Ru(NN)(CN)(4)](2) salts, in the formation of small amounts of salts of the dinuclear species [Ru-2(NN)(2)(CN)(7)](3). These cyanide-bridged anions have arisen from the combination of two monomer units [Ru(NN)(CN)(4)](2) following the loss of one cyanide, presumably as HCN. The crystal structures of [Nd(H2O)(5.5)][Ru-2(bipy)(2)(CN)(7)] center dot 11H(2)O and [Pr(H2O)(6)][Ru-2(phen)(2)(CN)(7)] center dot 9H(2)O show that the cyanoruthenate anions form Ru-CN-Ln bridges to the Ln(III) cations, resulting in infinite coordination polymers consisting of fused Ru(2)Ln(2)(mu-CN)(4) squares and Ru(4)Ln(2)(mu-CN)(6) hexagons, which alternate to form a one-dimensional chain. In [CH6N3](3)[Ru-2(bipy)(2)(CN)(7)] center dot 2H(2)O in contrast the discrete complex anions are involved in an extensive network of hydrogen-bonding involving terminal cyanide ligands, water molecules, and guanidinium cations. In the [Ru-2(NN)(2)(CN)(7)](3) anions themselves the two NN ligands are approximately eclipsed, lying on the same side of the central Ru-CN-Ru axis, such that their peripheries are in close contact. Consequently, when NN = 4,4'-Bu-t(2)-2,2'-bipyridine the steric bulk of the t-butyl groups prevents the formation of the dinuclear anions, and the only product is the simple salt of the monomer, [CH6N3](2)[Ru((t)Bu(2)bipy)(CN)(4)] center dot 2H(2)O. We demonstrated by electrospray mass spectrometry that the dinuclear by-product [Ru-2(phen)(2)(CN)(7)](3) could be formed in significant amounts during the synthesis of monomeric [Ru(phen)(CN)(4)](2) if the reaction time was too long or the medium too acidic. In the solid state the luminescence properties of [Ru-2(bipy)(2)(CN)(7)](3) (as its guanidinium salt) are comparable to those of monomeric [Ru(bipy)(CN)(4)](2), with a (MLCT)-M-3 emission at 581 nm

    Mechanism of Vanadium Leaching during Surface Weathering of Basic Oxygen Furnace Steel Slag Blocks: A Microfocus X-ray Absorption Spectroscopy and Electron Microscopy Study

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    © 2017 American Chemical Society. Basic oxygen furnace (BOF) steelmaking slag is enriched in potentially toxic V which may become mobilized in high pH leachate during weathering. BOF slag was weathered under aerated and air-excluded conditions for 6 months prior to SEM/EDS and μXANES analysis to determine V host phases and speciation in both primary and secondary phases. Leached blocks show development of an altered region in which free lime and dicalcium silicate phases were absent and Ca-Si-H was precipitated (CaCO 3 was also present under aerated conditions). μXANES analyses show that V was released to solution as V(V) during dicalcium silicate dissolution and some V was incorporated into neo-formed Ca-Si-H. Higher V concentrations were observed in leachate under aerated conditions than in the air-excluded leaching experiment. Aqueous V concentrations were controlled by Ca 3 (VO 4 ) 2 solubility, which demonstrate an inverse relationship between Ca and V concentrations. Under air-excluded conditions Ca concentrations were controlled by dicalcium silicate dissolution and Ca-Si-H precipitation, leading to relatively high Ca and correspondingly low V concentrations. Formation of CaCO 3 under aerated conditions provided a sink for aqueous Ca, allowing higher V concentrations limited by kinetic dissolution rates of dicalcium silicate. Thus, V release may be slowed by the precipitation of secondary phases in the altered region, improving the prospects for slag reuse

    Effects of finite-range interactions on the one-electron spectral properties of TTF-TCNQ

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    The electronic dispersions of the quasi-one-dimensional organic conductor TTF-TCNQ are studied by angle-resolved photoelectron spectroscopy (ARPES) with higher angular resolution and accordingly smaller step width than in previous studies. Our experimental results suggest that a refinement of the single-band 1D Hubbard model that includes finite-range interactions is needed to explain these photoemission data. To account for the effects of these finite-range interactions we employ a mobile quantum impurity scheme that describes the scattering of fractionalized particles at energies above the standard Tomonaga-Luttinger liquid limit. Our theoretical predictions agree quantitatively with the location in the (k,ω) plane of the experimentally observed ARPES structures at these higher energies. The nonperturbative microscopic mechanisms that control the spectral properties are found to simplify in terms of the exotic scattering of the charge fractionalized particles. We find that the scattering occurs in the unitary limit of (minus) infinite scattering length, which limit occurs within neutron-neutron interactions in shells of neutron stars and in the scattering of ultracold atoms but not in perturbative electronic condensed-matter systems. Our results provide important physical information on the exotic processes involved in the finite-range electron interactions that control the high-energy spectral properties of TTF-TCNQ. Our results also apply to a wider class of 1D and quasi-1D materials and systems that are of theoretical and potential technological interest.We thank Claus S. Jacobsen for providing the single crystals used in our ARPES studies. J.M.P.C. acknowledges the late Adilet Imambekov for discussions that were helpful in writing this paper. He also would like to thank Boston University's Condensed Matter Theory Visitors Program for support and the hospitality of MIT. J.M.P.C. and T.C. acknowledge the support from Fundacao para a Ciencia e Tecnologia (FCT) through the Grants No. UID/FIS/04650/2013 and No. PTDC/FIS-MAC/29291/2017, J.M.P.C. acknowledges that from the FCT Grants No. SFRH/BSAB/142925/2018 and No. POCI-01-0145-FEDER-028887, and T.C. acknowledges the support from the National Natural Science Foundation of China Grant No. 11650110443

    Evaluating automatic LFG f-structure annotation for the Penn-II treebank

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    Lexical-Functional Grammar (LFG: Kaplan and Bresnan, 1982; Bresnan, 2001; Dalrymple, 2001) f-structures represent abstract syntactic information approximating to basic predicate-argument-modifier (dependency) structure or simple logical form (van Genabith and Crouch, 1996; Cahill et al., 2003a) . A number of methods have been developed (van Genabith et al., 1999a,b, 2001; Frank, 2000; Sadler et al., 2000; Frank et al., 2003) for automatically annotating treebank resources with LFG f-structure information. Until recently, however, most of this work on automatic f-structure annotation has been applied only to limited data sets, so while it may have shown lsquoproof of conceptrsquo, it has not yet demonstrated that the techniques developed scale up to much larger data sets. More recent work (Cahill et al., 2002a,b) has presented efforts in evolving and scaling techniques established in these previous papers to the full Penn-II Treebank (Marcus et al., 1994). In this paper, we present a number of quantitative and qualitative evaluation experiments which provide insights into the effectiveness of the techniques developed to automatically derive a set of f-structures for the more than 1,000,000 words and 49,000 sentences of Penn-II. Currently we obtain 94.85% Precision, 95.4% Recall and 95.09% F-Score for preds-only f-structures against a manually encoded gold standard
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