31 research outputs found

    A review of e-maintenance capabilities and challenges

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    Within the era of e-manufacturing and e-business, e-maintenance provides the opportunity for a new maintenance generation. E-maintenance integrates existing telemaintenance principles, with web-services and modern e-collaboration principles. Collaboration allows not only to share and exchange information but also knowledge and (e)-intelligence. This paper outlines the basic capabilities provided by e-maintenance to companies as well as describes emerging challenges to benefit from these new operational improvement opportunitie

    Stochastic filtering approach for condition-based maintenance considering sensor degradation

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    This paper proposes a condition-based maintenance (CBM) policy for a deteriorating system whose state is monitored by a degraded sensor. In the literature of CBM, it is commonly assumed that inspection of system state is perfect or subject to measurement error. The health condition of the sensor, which is dedicated to inspect the system state, is completely ignored during system operation. However, due to the varying operation environment and aging effect, the sensor itself will suffer a degradation process and its performance deteriorates with time. In the presence of sensor degradation, the Kalman filter is employed in this paper to progressively estimate the system and the sensor state. Since the estimation of system state is subject to uncertainty, maintenance solely based on the estimated state will lead to a suboptimal solution. Instead, predictive reliability is used as a criterion for maintenance decision-making, which is able to incorporate the effect of estimation uncertainty. Preventive replacement is implemented when the estimated system reliability at inspection hits a specific threshold, which is obtained by minimizing the long-run maintenance cost rate. An example of wastewater treatment plant is used to illustrate the effectiveness of the proposed maintenance policy. It can be concluded through our research that: 1) disregarding the sensor degradation while it exists will significantly increase the maintenance cost and 2) the negative impact of sensor degradation can be diminished via proper inspection and filtering methods

    Modelling and application of condition-based maintenance for a two-component system with stochastic and economic dependencies

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    This paper develops a model of a condition-based maintenance policy for a two-component system with both stochastic and economic dependencies. The stochastic dependency is such that the degradation rate of each component depends not only on its own state (degradation level) but also on the state of the other component. The economic dependency is such that combining multiple maintenance activities has lower cost than performing maintenance on components separately. To select a component or components to be preventively maintained, adaptive preventive maintenance and opportunistic maintenance rules are proposed. A cost model is developed to find the optimal values of decision variables. A case study of a gearbox system demonstrates the utility of the proposed model

    The Exploration of Effects of Chinese Cultural Values on the Attitudes and Behaviors of Chinese Restaurateurs Toward Food Safety Training

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    Citation: Liu, P., & Kwon, J. (2013). The exploration of effects of Chinese cultural values on the attitudes and behaviors of Chinese restaurateurs toward food safety training. Journal of Environmental Health, 75(10), 38-46.Foodborne illness is a challenge in the production and service of ethnic foods. The purpose of the study described in this article was to explore variables influencing the behaviors of U.S. Chinese restaurant owners/operators regarding the provision of food safety training in their restaurants. Seventeen major Chinese cultural values were identified through individual interviews with 20 Chinese restaurant owners/operators. Most participants felt satisfied with their previous health inspections. Several expressed having difficulty, however, following the health inspectors’ instructions and in understanding the health inspection report. A few participants provided food safety training to their employees due to state law. Lack of money, time, labor/energy, and a perceived need for food safety training were recognized as major challenges to providing food safety training in Chinese restaurants. Videos, case studies, and food safety training handbooks were the most preferred food safety training methods of Chinese restaurant owners/operators, and Chinese was the preferred language in which to conduct the training

    Contribution a une intelligence distribuee dans les equipements de niveau zero des processus industriels complexes

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    SIGLEAvailable from INIST (FR), Document Supply Service, under shelf-number : T 81240 / INIST-CNRS - Institut de l'Information Scientifique et TechniqueFRFranc

    Advanced Maintenance Services for Promoting Sustainability

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    Ecology and industry, which have been many times considered as antagonists, are now associated together in the sustainability concept to support the three social / economic / environment pillars. In that way, industrial enterprises and more precisely manufacturing ones seek to integrate environment into their strategy by conducting an innovative rationalization of the production as promoted by industrial ecology and circular economy paradigms. This rationalization is favoring the evolution from product to a Product-Service Systems approach (PSS). The continuity of these services is mainly carried out by the maintenance which is no longer an aftermarket service needed for product (system) functionality but rather an inherent service function of the product (system). Thus this paper aims to investigate the role of maintenance to contribute to the development of these paradigms. It is based first on describing the main features of industrial ecology/circular economy transposing the nature concepts to industrial system. It leads to define key principles and levers to be addressed for the development of industrial ecosystems. Then maintenance activity is globally presented allowing, in a second step, to place maintenance services already existing in line with some of these principles and levers (ex. green maintenance), but also to explore advanced maintenance services more able to support promotion of industrial ecosystem by covering others principles and levers. These advanced services can be built from conventional maintenance processes but integrating sustainability goal (ex. prognostics of energy efficiency) or from innovative processes (ex. regenerative management). Finally scientific issues related to these advanced maintenance services are underlining and should concretize future research directions for researchers/practitioners working on maintenance field
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