841 research outputs found

    Application of machine learning and expert systems to Statistical Process Control (SPC) chart interpretation

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    Statistical Process Control (SPC) charts are one of several tools used in quality control. Other tools include flow charts, histograms, cause and effect diagrams, check sheets, Pareto diagrams, graphs, and scatter diagrams. A control chart is simply a graph which indicates process variation over time. The purpose of drawing a control chart is to detect any changes in the process signalled by abnormal points or patterns on the graph. The Artificial Intelligence Support Center (AISC) of the Acquisition Logistics Division has developed a hybrid machine learning expert system prototype which automates the process of constructing and interpreting control charts

    Impact of Amur Honeysuckle (Lonicera maackii) Leachate on Culex pipiens Life History Attributes

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    The purpose of this study was to look at the impact of a highly invasive plant, Lonicera maackii, on the primary vector of West Nile Virus in the Eastern United States, Culex pipiens. Three different assays using two different microcosms experiments were conducted to determine the rate of survivorship, pupation, emergence, and larval growth of mosquito larvae in native (Platanus occidentalis and Acer saccharum) and invasive (L. maackii leaf and flower) leachates. It was found that L. maackii has the potential to increase mosquito populations due to the fast decaying nature of its leaves and flowers which create an ideal leachate for mosquito larvae

    Minimization of the Effects of Secondary Reactions on Turbine Film Cooling in a Fuel Rich Environment

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    The demand for increased thrust, higher engine efficiency, and reduced fuel consumption has increased the turbine inlet temperature and pressure in modern gas turbine engines. The outcome of these higher temperatures and pressures is the potential for unconsumed radical species to enter the turbine. Because modern cooling schemes for turbine blades involve injecting cool, oxygen rich air adjacent to the surface, the potential for reaction with radicals in the mainstream flow and augmented heat transfer to the blade arises. This study evaluated various configurations of multiple cylindrical rows of cooling holes in terms of both heat release and effective downstream cooling. It confirmed that a build-up of rows of coolant could be used to effectively protect the wall in a fuel-rich environment. It demonstrated slot and trench configurations to be effective in reducing the heat flux to the wall. Also, the Swirler and Two Row Upstream configurations were shown to highly increase radical consumption. Finally, this research developed infrared imaging as a technique for evaluating the wall temperature of the film cooled surface

    CLIPS application user interface for the PC

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    The majority of applications that utilize expert system development programs for their knowledge representation and inferencing capability require some form of interface with the end user. This interface is more than likely an interaction through the computer screen. When building an application the user interface can prove to be the most difficult and time consuming aspect to program. Commercial products currently exist which address this issue. To keep pace C Language Integrated Production System (CLIPS) will need to find a solution for their lack of an easy to use Application User Interface (AUI). This paper represents a survey of the DoD CLIPS' user community and provides the backbone of a possible solution

    Optimal detection of homogeneous segment of observations in stochastic sequence

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    A Markov process is registered. At random moment θ\theta the distribution of observed sequence changes. Using probability maximizing approach the optimal stopping rule for detecting the change is identified. Some explicit solution is obtained.Comment: 13 page

    Implementing evaluation of the measurement process in an automotive manufacturer: a case study

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    Reducing process variability is presently an area of much interest in manufacturing organizations. Programmes such as Six Sigma robustly link the financial performance of the organization to the degree of variability present in the processes and products of the organization. Data, and hence measurement processes, play an important part in driving such programmes and in making key manufacturing decisions. In many organizations, however, little thought is given to the quality of the data generated by such measurement processes. By using potentially flawed data in making fundamental manufacturing decisions, the quality of the decision-making process is undermined and, potentially, significant costs are incurred. Research in this area is sparse and has concentrated on the technicalities of the methodologies available to assess measurement process capability. Little work has been done on how to operationalize such activities to give maximum benefit. From the perspective of one automotive company, this paper briefly reviews the approaches presently available to assess the quality of data and develops a practical approach, which is based on an existing technical methodology and incorporates simple continuous improvement tools within a framework which facilitates appropriate improvement actions for each process assessed. A case study demonstrates the framework and shows it to be sound, generalizable and highly supportive of continuous improvement goals

    Don't know, can't know: Embracing deeper uncertainties when analysing risks

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    This article is available open access through the publisher’s website at the link below. Copyright @ 2011 The Royal Society.Numerous types of uncertainty arise when using formal models in the analysis of risks. Uncertainty is best seen as a relation, allowing a clear separation of the object, source and ‘owner’ of the uncertainty, and we argue that all expressions of uncertainty are constructed from judgements based on possibly inadequate assumptions, and are therefore contingent. We consider a five-level structure for assessing and communicating uncertainties, distinguishing three within-model levels—event, parameter and model uncertainty—and two extra-model levels concerning acknowledged and unknown inadequacies in the modelling process, including possible disagreements about the framing of the problem. We consider the forms of expression of uncertainty within the five levels, providing numerous examples of the way in which inadequacies in understanding are handled, and examining criticisms of the attempts taken by the Intergovernmental Panel on Climate Change to separate the likelihood of events from the confidence in the science. Expressing our confidence in the adequacy of the modelling process requires an assessment of the quality of the underlying evidence, and we draw on a scale that is widely used within evidence-based medicine. We conclude that the contingent nature of risk-modelling needs to be explicitly acknowledged in advice given to policy-makers, and that unconditional expressions of uncertainty remain an aspiration

    Target value design: using collaboration and a lean approach to reduce construction cost

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    Target Costing is an effective management technique that has been used in manufacturing for decades to achieve cost predictability during new products development. Adoption of this technique promises benefits for the construction industry as it struggles to raise the number of successful outcomes and certainty of project delivery in terms of cost, quality and time. Target Value Design is a management approach that takes the best features of Target Costing and adapts them to the peculiarities of construction. In this paper the concept of Target Value Design is introduced based on the results of action research carried out on 12 construction projects in the USA. It has been shown that systemic application of Target Value Design leads to significant improvement of project performance – the final cost of projects was on average 15% less than market cost. The construction industry already has approaches that have similarities with elements of the Target Value Design process or uses the same terminology, e.g. Partnering and Target Cost Contracts, Cost planning, etc. Following an exploration of the similarities and differences Target Value Design is positioned as a form of Target Costing for construction that offers a more reliable route to successful projects outcomes

    The interaction of lean and building information modeling in construction

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    Lean construction and Building Information Modeling are quite different initiatives, but both are having profound impacts on the construction industry. A rigorous analysis of the myriad specific interactions between them indicates that a synergy exists which, if properly understood in theoretical terms, can be exploited to improve construction processes beyond the degree to which it might be improved by application of either of these paradigms independently. Using a matrix that juxtaposes BIM functionalities with prescriptive lean construction principles, fifty-six interactions have been identified, all but four of which represent constructive interaction. Although evidence for the majority of these has been found, the matrix is not considered complete, but rather a framework for research to explore the degree of validity of the interactions. Construction executives, managers, designers and developers of IT systems for construction can also benefit from the framework as an aid to recognizing the potential synergies when planning their lean and BIM adoption strategies
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