208 research outputs found

    An analysis of commitment strategies in planning: The details

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    We compare the utility of different commitment strategies in planning. Under a 'least commitment strategy', plans are represented as partial orders and operators are ordered only when interactions are detected. We investigate claims of the inherent advantages of planning with partial orders, as compared to planning with total orders. By focusing our analysis on the issue of operator ordering commitment, we are able to carry out a rigorous comparative analysis of two planners. We show that partial-order planning can be more efficient than total-order planning, but we also show that this is not necessarily so

    The min-conflicts heuristic: Experimental and theoretical results

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    This paper describes a simple heuristic method for solving large-scale constraint satisfaction and scheduling problems. Given an initial assignment for the variables in a problem, the method operates by searching through the space of possible repairs. The search is guided by an ordering heuristic, the min-conflicts heuristic, that attempts to minimize the number of constraint violations after each step. We demonstrate empirically that the method performs orders of magnitude better than traditional backtracking techniques on certain standard problems. For example, the one million queens problem can be solved rapidly using our approach. We also describe practical scheduling applications where the method has been successfully applied. A theoretical analysis is presented to explain why the method works so well on certain types of problems and to predict when it is likely to be most effective

    An extended abstract: A heuristic repair method for constraint-satisfaction and scheduling problems

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    The work described in this paper was inspired by a surprisingly effective neural network developed for scheduling astronomical observations on the Hubble Space Telescope. Our heuristic constraint satisfaction problem (CSP) method was distilled from an analysis of the network. In the process of carrying out the analysis, we discovered that the effectiveness of the network has little to do with its connectionist implementation. Furthermore, the ideas employed in the network can be implemented very efficiently within a symbolic CSP framework. The symbolic implementation is extremely simple. It also has the advantage that several different search strategies can be employed, although we have found that hill-climbing methods are particularly well-suited for the applications that we have investigated. We begin the paper with a brief review of the neural network. Following this, we describe our symbolic method for heuristic repair

    'Outside' Intervention in Japanese Companies: Its Determinants and Implications for Mangers

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    This paper estimates the determinants of appointments of 'outsiders' -- directors previously employed by banks or other non-financial firms -- to the boards of large (non-financial) Japanese companies. Appointments of both types of 'outsiders' increase with poor stock performance; those of bank outsiders also increase with negative current income. Appointments of bank outsiders are related to firm debt levels; those of corporate outsiders, to shareholder concentration and group affiliation, Both types of outsider appointments appear to be disciplinary -- top executive turnover increase substantially in the same year. Additional evidence on subsequent firm performance suggests that "bank" directors are appointed in financially distressed or contracting firms, while "corporate" directors are appointed in firms with temporary problems.

    Growth performance of nursery pigs fed BIOSAF yeast, alone or in combination with an in-feed antimicrobial

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    Swine research, 2005 is known as Swine day, 2005A total of 280 pigs were used in a 28-d growth study to evaluate the effects of feeding the antimicrobial carbadox, BIOSAF (0.4%), and the combination of carbadox and BIOSAF yeast (0.15%) in nursery pig diets. Over the length of the entire trial, pigs fed the diet containing carbadox alone had greater ADG than did pigs fed the control diet or the diet containing 0.4% BIOSAF. Overall, pigs fed the diet containing both carbadox and 0.15% BIOSAF had greater ADG than did pigs fed the control diet or the diet containing 0.4% BIOSAF (P<0.04), although their growth performance did not differ from that of pigs fed carbadox alone. Antibody titers in response to routine vaccination against Mycoplasma hyopneumoniae were not affected by dietary treatment. There was no evidence that BIOSAF improved growth performance of nursery pigs, either alone or in combination with the carbadox. It is possible that the interactive effects of BIOSAF that have been reported for other in-feed antibiotics are not present when BIOSAF is combined with carbadox, or perhaps interactive effects are only observed when carbadox itself exerts a more potent stimulation of ADG in nursery pigs

    Effects of a seaweed extract on weanling pig growth performance and immune function during an acute enteric disease challenge

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    A total of 95 pigs (initially 15 lb and 17 d of age) was used in a 28 d growth trial to determine the effects of Ascophyllum nodosum seaweed extract (ANOD) on weanling pig growth performance and immune function in response to enteric disease challenge with Salmonella typhimurium (ST). Experimental treatments were arranged in a 2 x 4 factorial with main effects of disease challenge (control vs. ST challenge) and dietary addition of ANOD (0, 0.5, 1.0, and 2.0% of diet). Results suggest little beneficial effect of dietary ANOD on growth performance or immune response in the presence or absence of ST challenge

    Artificial Intelligence for Rapid Meta-Analysis: Case Study on Ocular Toxicity of Hydroxychloroquine.

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    BACKGROUND: Rapid access to evidence is crucial in times of an evolving clinical crisis. To that end, we propose a novel approach to answer clinical queries, termed rapid meta-analysis (RMA). Unlike traditional meta-analysis, RMA balances a quick time to production with reasonable data quality assurances, leveraging artificial intelligence (AI) to strike this balance. OBJECTIVE: We aimed to evaluate whether RMA can generate meaningful clinical insights, but crucially, in a much faster processing time than traditional meta-analysis, using a relevant, real-world example. METHODS: The development of our RMA approach was motivated by a currently relevant clinical question: is ocular toxicity and vision compromise a side effect of hydroxychloroquine therapy? At the time of designing this study, hydroxychloroquine was a leading candidate in the treatment of coronavirus disease (COVID-19). We then leveraged AI to pull and screen articles, automatically extract their results, review the studies, and analyze the data with standard statistical methods. RESULTS: By combining AI with human analysis in our RMA, we generated a meaningful, clinical result in less than 30 minutes. The RMA identified 11 studies considering ocular toxicity as a side effect of hydroxychloroquine and estimated the incidence to be 3.4% (95% CI 1.11%-9.96%). The heterogeneity across individual study findings was high, which should be taken into account in interpretation of the result. CONCLUSIONS: We demonstrate that a novel approach to meta-analysis using AI can generate meaningful clinical insights in a much shorter time period than traditional meta-analysis

    Corn particle size and pelleting influence on growth performance, fecal shedding, and lymph node infection rates of salmonella enterica serovar typhimurium

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    Ninety-six pigs (initially 13.8 lb.) were used in a 28-d trial to determine the interactive effects between pelleting and particle size on Salmonella serovar Typhimurium shedding and colonization in a young growing pig model. The experiment was a 2 × 2 factorial arrangement consisting of meal or pelleted diets with fine or coarse ground corn. Pigs were fed the diets 1 wk pre-salmonella inoculation and allotted based on weight to one of four dietary treatments. For the main effect of particle size, pigs fed finer ground corn had significantly improved feed efficiency (P0.82). There was no difference in salmonella infection rates of mesenteric lymph nodes obtained on d 28 between treatments or main effects. Finer grinding and meal diets generally improved growth, feed intake, and feed efficiency compared to pigs fed coarser ground or pelleted feeds. However, particle size or diet form did not alter fecal shedding or mesenteric lymph node infection rates of salmonella organisms in our study

    Exploiting data semantics to discover, extract, and model web sources

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    We describe DEIMOS, a system that automatically discovers and models new sources of information. The system exploits four core technologies developed by our group that makes an end-to-end solution to this problem possible. First, given an example source, DEIMOS finds other similar sources online. Second, it invokes and extracts data from these sources. Third, given the syntactic structure of a source, DEIMOS maps its inputs and outputs to semantic types. Finally, it infers the source’s semantic definition, i.e., the function that maps the inputs to the outputs. DEIMOS is able to successfully automate these steps by exploiting a combination of background knowledge and data semantics. We describe the challenges in integrating separate components into a unified approach to discovering, extracting and modeling new online sources. We provide an end-toend validation of the system in two information domains to show that it can successfully discover and model new data sources in those domains. 1
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