4,354 research outputs found

    Premise Selection and External Provers for HOL4

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    Learning-assisted automated reasoning has recently gained popularity among the users of Isabelle/HOL, HOL Light, and Mizar. In this paper, we present an add-on to the HOL4 proof assistant and an adaptation of the HOLyHammer system that provides machine learning-based premise selection and automated reasoning also for HOL4. We efficiently record the HOL4 dependencies and extract features from the theorem statements, which form a basis for premise selection. HOLyHammer transforms the HOL4 statements in the various TPTP-ATP proof formats, which are then processed by the ATPs. We discuss the different evaluation settings: ATPs, accessible lemmas, and premise numbers. We measure the performance of HOLyHammer on the HOL4 standard library. The results are combined accordingly and compared with the HOL Light experiments, showing a comparably high quality of predictions. The system directly benefits HOL4 users by automatically finding proofs dependencies that can be reconstructed by Metis

    The Platycerus (Coleoptera, Lucanidae) of California, with the Recognition of Platycerus cribripennis Van Dyke as a Valid Species

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    Th e status of Platycerus cribripennis Van Dyke, generally treated as a synonym of P. marginalis Casey, has been unclear. Here we recognize and redescribe P. cribripennis, which is endemic to the coastal mountains of California, as a valid species due to its unique morphology. A key to the Platycerus of California is presented, and the distributions of the recognized species are discussed

    Decidability of Univariate Real Algebra with Predicates for Rational and Integer Powers

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    We prove decidability of univariate real algebra extended with predicates for rational and integer powers, i.e., (xn∈Q)(x^n \in \mathbb{Q}) and (xn∈Z)(x^n \in \mathbb{Z}). Our decision procedure combines computation over real algebraic cells with the rational root theorem and witness construction via algebraic number density arguments.Comment: To appear in CADE-25: 25th International Conference on Automated Deduction, 2015. Proceedings to be published by Springer-Verla

    Translational energy dependence of cross sections for reactions of OH− (H2O) n with CO2 and SO2

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    This is the publisher's version, also available electronically from http://scitation.aip.org/content/aip/journal/jcp/80/10/10.1063/1.446510.A tandem mass spectrometer has been used to measure cross sections for reactions of the solvated negative ions OH−(H2O) n , where 0≤n≤3, with the neutral molecules CO2 and SO2 over the range of reactant translational energy 0.15–25.0 eV (LAB). The reactions observed include solvent switching, collisional dissociation, and charge transfer. The exoergic solvent switching reactions are very rapid, having cross sections which exceed a hundred square Angstroms at low energies. These cross sections decrease approximately as (energy)−0.5 up to 1 eV and then decrease much more rapidly at higher collision energies. Estimates of bond dissociation energies for the cluster ions are derived from the measured translational energy thresholds for the endothermic collisional dissociationreactions

    Southwestern Minnesota Farm Business Management Association 2008 Annual Report

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    Average net farm income was 190,901in2008forthe99farmsincludedinthisannualreportoftheSouthwesternMinnesotaFarmBusinessManagementAssociation.Averageearningsdecreasedby21190,901 in 2008 for the 99 farms included in this annual report of the Southwestern Minnesota Farm Business Management Association. Average earnings decreased by 21% from the average of 242,267 in 2007 (Figure 1). 2008 ended a steady trend of increasing year-to-year incomes for these farms from 2001 to 2007. Crop farms, with historically high corn and soybean prices, remained very profitable. However, specialized hog farms, which had been very profitable for the past four years, experienced substantial losses. Highlights of association financial results for 2008: Median net farm income was 178,874,slightlylowerthantheaverage,indicatingthattheaveragewasincreasedbyhighprofitsofthemostprofitablefarms.Thiseffectwasnotaslargeaspreviousyears,likelybecauseoflossesbylargerhogoperations.•Thedifferencebetweenthemostprofitablefarmsandtheleastprofitablecontinuedtoincrease.Themostprofitable20178,874, slightly lower than the average, indicating that the average was increased by high profits of the most profitable farms. This effect was not as large as previous years, likely because of losses by larger hog operations. • The difference between the most profitable farms and the least profitable continued to increase. The most profitable 20% of the farms earned an average net farm income of 449,997 while the least profitable lost −29,476.•Averagegrosscashincomeincreasedby20-29,476. • Average gross cash income increased by 20% while expenses increased 22% for the average farm. Most of the reduction in income resulted from a lower value of inventory changes. Inventories did increase in value, but not by as much as in 2007. • Government payments accounted for 2% of gross cash farm income (Figure 2). Crop sales accounted for 50% of income while livestock sales were 42%. • Average rate of return on assets (ROA) was 11% with assets valued at adjusted cost or book value, down from 17% in 2007 (Figure 3). Rate of return on equity (ROE) averaged 15%, down from 25 percent. The fact that ROE exceeded ROA indicates that debt capital earned more than its cost. • The average farm generated net worth growth of 115,999. The average debt-to-asset ratio improved slightly to 39%, down from 40% (Figure 4). • Corn yields were up but soybean yields were down. Corn averaged 172 bushels per acre compared to 162 in 2007. Soybeans yields decreased to 44 bushels from 49 in 2007 (Figure 5). • Both corn and soybean prices received increased by over 50% to 4.51forcornand4.51 for corn and 10.83 for soybeans. • The cost to raise an acre of corn (with land rent) increased by 23% while soybean costs increased by 21%. The cost to produce a bushel of corn on cash rented land increased from 2.58perbushelin2007to2.58 per bushel in 2007 to 2.90 in 2008, while soybean costs per bushel increased from 6.14to6.14 to 7.21. • The average specialized hog operation (those with 70% of sales from hogs or pigs) lost over 150,000in2008(Figure6).Allotherfarmtypeswithenoughfarmstoreportaveragednetincomesveryclosetotheassociationaverage.•Basedonrateofreturnonassets,cropfarms(thosewith70150,000 in 2008 (Figure 6). All other farm types with enough farms to report averaged net incomes very close to the association average. • Based on rate of return on assets, crop farms (those with 70% of sales from crops) were the most profitable type of farm in 2008, with an ROA of 14.7% (Figure 7). All other farm types were profitable except specialized hog farms, which earned a -2.2% ROA. • Hog farms, after large losses in 2008, replaced Crop/Beef farms as the type of farm group with the highest debt to asset ratio at the end of the year (Figure 8). • The largest farms, those with gross revenue over 1,000,000, were the least profitable based on rate of return on assets. This group earned an average ROA of 7% compared to 14% for farms that grossed between 500,000and500,000 and 1,000,000. • With exceptionally high feed prices, no hog or beef enterprise, with the exception of contract growing of hogs (where the contractor provided the feed) covered even direct costs of production. The report provides additional information on profitability, liquidity, and solvency as well as other whole-farm information and detailed information on crop and livestock enterprises. Also reported are whole-farm financial condition and performance by county, sales size class, type of farm, debt-to-asset ratio, and age of operator.Agricultural Finance, Farm Management,

    Relating two standard notions of secrecy

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    Two styles of definitions are usually considered to express that a security protocol preserves the confidentiality of a data s. Reachability-based secrecy means that s should never be disclosed while equivalence-based secrecy states that two executions of a protocol with distinct instances for s should be indistinguishable to an attacker. Although the second formulation ensures a higher level of security and is closer to cryptographic notions of secrecy, decidability results and automatic tools have mainly focused on the first definition so far. This paper initiates a systematic investigation of the situations where syntactic secrecy entails strong secrecy. We show that in the passive case, reachability-based secrecy actually implies equivalence-based secrecy for digital signatures, symmetric and asymmetric encryption provided that the primitives are probabilistic. For active adversaries, we provide sufficient (and rather tight) conditions on the protocol for this implication to hold.Comment: 29 pages, published in LMC

    Ant Diversity in Two Southern Minnesota Tallgrass Prairie Restoration Sites

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    There is little basic information about ant species richness and abundance in tall grass prairie restorations despite the importance of ants to plant community structure and function. We compared ant abundance and richness, vascular plant cover and richness, and soil compaction at two southern Minnesota grassland restoration sites, a prairie reconstruction and a prairie remnant undergoing rehabilitation. We collected a total of 3,523 ants from 12 different species. Plant species richness ranged from 45 in the prairie reconstruction to 95 in the remnant prairie. We found five more species of ants and significantly higher mean ant species richness per plot in the more heterogeneous prairie remnant with higher plant diversity, especially forbs, than in the prairie reconstruction where plant species diversity was lower. Our study found 10 new ant species records in Le Sueur and Nicollet counties, Minnesota. Because of the paucity of information about ant species in the upper Midwest, it is difficult to fully compare our results to those of other restored or natural areas in the area. Our study provides an important baseline census for two different types of tallgrass prairie restorations

    New Product Innovation with Multiple Features and Technology Constraints

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    We model a firm\u27s decisions about product innovation, focusing on the extent to which features should be improved or changed in the succession of models that comprise a life cycle. We show that the structure of the internal and external environment in which a firm operates suggests when to innovate to the technology frontier. The criterion is maximization of the expected present value of products during the life cycle. Computational studies complement the theoretical results and lead to insights about when to bundle innovations across features. The formalization was influenced by extensive interviews with managers in a high-technology firm that dominates its industry

    Proof Theory, Transformations, and Logic Programming for Debugging Security Protocols

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    We define a sequent calculus to formally specify, simulate, debug and verify security protocols. In our sequents we distinguish between the current knowledge of principals and the current global state of the session. Hereby, we can describe the operational semantics of principals and of an intruder in a simple and modular way. Furthermore, using proof theoretic tools like the analysis of permutability of rules, we are able to find efficient proof strategies that we prove complete for special classes of security protocols including Needham-Schroeder. Based on the results of this preliminary analysis, we have implemented a Prolog meta-interpreter which allows for rapid prototyping and for checking safety properties of security protocols, and we have applied it for finding error traces and proving correctness of practical examples

    Analysis of how Dual-tasking Effects Selected Gait Variables in Older Adults with a Known Relative Power

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    Please view abstract in the attached PDF file
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