54 research outputs found

    Diagnostic reasoning techniques for selective monitoring

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    An architecture for using diagnostic reasoning techniques in selective monitoring is presented. Given the sensor readings and a model of the physical system, a number of assertions are generated and expressed as Boolean equations. The resulting system of Boolean equations is solved symbolically. Using a priori probabilities of component failure and Bayes' rule, revised probabilities of failure can be computed. These will indicate what components have failed or are the most likely to have failed. This approach is suitable for systems that are well understood and for which the correctness of the assertions can be guaranteed. Also, the system must be such that changes are slow enough to allow the computation

    Task planning and control synthesis for robotic manipulation in space applications

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    Space-based robotic systems for diagnosis, repair and assembly of systems will require new techniques of planning and manipulation to accomplish these complex tasks. Results of work in assembly task representation, discrete task planning, and control synthesis which provide a design environment for flexible assembly systems in manufacturing applications, and which extend to planning of manipulatiuon operations in unstructured environments are summarized. Assembly planning is carried out using the AND/OR graph representation which encompasses all possible partial orders of operations and may be used to plan assembly sequences. Discrete task planning uses the configuration map which facilitates search over a space of discrete operations parameters in sequential operations in order to achieve required goals in the space of bounded configuration sets

    Formulation and Search of Assembly Sequence Design Spaces for Efficient Use of Assembly Plant Resources for New Products

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    Efficient procedures for generation of feasible assembly sequences and effective utilization of available assembly plant resources can greatly reduce the development time and cost of platforms for new product family members. This article presents a method to generate feasible assembly sequences and an approach to select an assembly process that reduces the existing plant modification cost. Assembly sequence design space is combinatorial in nature. Mathematical models to solve the effects of constraints on these spaces and algorithms to efficiently enumerate feasible spaces are explored in this research. Algorithms to search the feasible space to identify assembly process that can reduce the modification cost of the existing assembly plant can help increase utilization of existing resources. A software application that implements the method and algorithms has been developed. The algorithms use the concept of recursive partitioning of set of components to generate assembly sequence space. The assembly processes are then evaluated to determine the process that maximizes resource utilization for new platforms. The application of the proposed approach is demonstrated using automotive underbody front structure family.Yeshttps://us.sagepub.com/en-us/nam/manuscript-submission-guideline

    Parts verification for multi-level-dependent demand manufacturing systems: a recognition and classification structure

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    This research has developed and implemented a part recognition and classification structure to execute parts verification in a multi-level dependent demand manufacturing system. The part recognition algorithm enables the parent and child relationship between parts to be recognised in a finite-capacitated manufacturing system. This algorithm was developed using SIMAN simulation language and implemented in a multi-level dependent demand manufacturing simulation model. The part classification structure enables the modelling of a multi-level dependent demand manufacturing between parts to be carried out effectively. The part classification structure was programmed using Visual Basic Application (VBA) and was integrated to the work-to-list generated from a simulated MRP model. This part classification structure was then implemented in the multi-level dependent demand manufacturing simulation model. Two stages of implementation, namely parameterisation and execution, of the part recognition and classification structure were carried out. A real case study was used and five detail steps of execution were processed. Simulation experiments and MRP were run to verify and validate the part recognition and classification structure. The results led to the conclusion that implementation of the recognition and classification structure has effectively verified the correct parts and sub-assemblies used for the correct product and order. No parts and sub-assemblies shortages were found, and the quantity required was produced. The scheduled release for some orders was delayed due to overload of the required resources. When the loading is normal, all scheduled release timing is adhered to. The recognition and classification structure has a robust design; hence it can be easily adapted to new systems parameter to study a different or more complex case

    Tecido urbano e mercado imobiliário em São Paulo: metodologia de estudo com base na Décima Urbana de 1809

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    Este artigo apresenta uma metodologia inédita de espacialização da Décima Urbana, primeiro imposto predial estabelecido para as cidades brasileiras. Focaliza o caso de São Paulo, em 1809. Os dados recolhidos na documentação textual foram processados em banco de dados e cartografados na primeira planta cadastral da cidade, elaborada pelo engenheiro Carlos Bresser, entre 1844-1847, e confrontados com a documentação iconográfica dos viajantes e de Militão Augusto de Azevedo, de modo a precisar as informações obtidas. A Décima Urbana de 1809 contém informações sobre a localização dos imóveis, seus proprietários, inquilinos, tipologias (casas térreas, sobrados, lojas), finalidades (uso próprio, aluguel), usos (residencial, comercial, misto) e valor, que hoje nos permitem reconstituir hipoteticamente o velho tecido urbano da cidade de São Paulo e aspectos da dinâmica do seu mercado imobiliário em fins do período colonial.This article presents a new spatialisation methodology for the Décima Urbana, the first property tax established in Brazilian cities. The case of São Paulo in 1809 is studied. The data gathered from textual documentation was processed in a database and cartographed on the first official city plan, elaborated by engineer Carlos Bresser between 1844-1847, and then confronted with the iconographic documentation produced by visiting travellers and by photographer Militão Augusto de Azevedo, so as to cross-reference the information obtained. The Décima Urbana of 1809 contains data about the siting of buildings, their proprietors, tenants, typology (single and two-storey houses, shops), finalities (own use, rent), uses (residential, commercial, mixed) and value. This allows for the present day hypothetical reconstruction of old São Paulo's urban mesh and of aspects of the real estate market dynamics at the end of the colonial period
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