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Optimal Production Control of Hybrid Manufacturing/Remanufacturing Failure-Prone Systems under Diffusion-Type Demand

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Applied Mathematics 2013年第3期4卷 550-559页

作者： Samir Ouaret Vladimir Polotski jean-pierre kenné Ali Gharbi école de Technologie Supérieure Montreal Canada

The problem of production control for a hybrid manufacturing/remanufacturing system under uncertainty is analyzed. Two sources of uncertainty are considered: machines are subject to random breakdowns and repairs, and demand level is modeled as a diffusion type stochastic process. Contrary to most of studies where the demand level is considered constant and fewer results where the demand is modeled as a Poisson process with few discrete levels and exponentially distributed switching time, the demand is modeled here as a diffusion type process. In particular Wiener and Ornstein-Uhlenbeck processes for cumulative demands are analyzed. We formulate the stochastic control problem and develop optimality conditions for it in the form of Hamilton-Jacobi-Bellman (HJB) partial differential equations (PDEs). We demonstrate that HJB equations are of the second order contrary to the case of constant demand rate (corresponding to the average demand in our case), where HJB equations are linear PDEs. We apply the Kushner-type finite difference scheme and the policy improvement procedure to solve HJB equations numerically and show that the optimal production policy is of hedging-point type for both demand models we have introduced, similarly to the known case of a constant demand. Obtained results allow to compute numerically the optimal production policy in hybrid manufacturing/ remanufacturing systems taking into account the demand variability, and also show that Kushner-type discrete scheme can be successfully applied for solving underlying second order HJB equations.

关键词： Stochastic Control Manufacturing Systems Optimization Failure Random Process

Failure Prediction and Intelligent Maintenance of a Transportation Company’s Urban Fleet

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Journal of Transportation Technologies 2023年第1期13卷 1-17页

作者： Crépin Foké jean-pierre kenné Ngongang Somen Bill Diego Mechanical Engineering Department University of Quebec école de Technologie Supérieure Montreal Canada

The present work deals with intelligent vehicle fleet maintenance and prediction. We propose an approach based primarily on the history of failures data and on the geographical data system. The objective here is to predict the date of failures for a fleet of vehicles in order to allow the maintenance department to efficiently deploy the proper resources;we further provide specific details regarding the origins of failures, and finally, give recommendations. This study used the Société de transport de Montréal (STM)’s historical bus failure data as well as weather data from Environment Canada. We thank Facebook’s Prophet, Simple Feed-forward, and Beats algorithms (Uber), we proposed a set of computer codes that allow us to identify the 20% of buses that are responsible for the 80% of failures by mean of the failure history. Then, we deepened our study on the unreliable equipments identified during the diffusion of our computer code This allowed us to propose probable predictions of the dates of future failures. To ensure the validity of the proposed algorithm, we carried out simulations with more than 250,000 data. The results obtained are similar to the predicted theoretical values.

关键词： Maintenance 4.0 Digital Technologies Failureprediction Artificial Intelligence Artificial Intelligence Prediction Algorithm

Production Planning of a Failure-Prone Manufacturing/Remanufacturing System with Production-Dependent Failure Rates

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Applied Mathematics 2014年第10期5卷 1557-1572页

作者： Annie Francie Kouedeu jean-pierre kenné pierre Dejax Victor Songmene Vladimir Polotski L’Université Nantes Angers Le Mans école des Mines de Nantes Nantes France Mechanical Engineering Department Laboratory of Integrated Production Technologies Université du Québec école de Technologie Supérieure Montreal Canada

This paper deals with the production-dependent failure rates for a hybrid manufacturing/remanufacturing system subject to random failures and repairs. The failure rate of the manufacturing machine depends on its production rate, while the failure rate of the remanufacturing machine is constant. In the proposed model, the manufacturing machine is characterized by a higher production rate. The machines produce one type of final product and unmet demand is backlogged. At the expected end of their usage, products are collected from the market and kept in recoverable inventory for future remanufacturing, or disposed of. The objective of the system is to find the production rates of the manufacturing and the remanufacturing machines that would minimize a discounted overall cost consisting of serviceable inventory cost, backlog cost and holding cost for returns. A computational algorithm, based on numerical methods, is used for solving the optimality conditions obtained from the application of the stochastic dynamic programming approach. Finally, a numerical example and sensitivity analyses are presented to illustrate the usefulness of the proposed approach. Our results clearly show that the optimal control policy of the system is obtained when the failure rates of the machine depend on its production rate.

关键词： Stochastic Process Optimal Control Reverse Logistics Production Planning Numerical Methods

Development of a Tool Cost Optimization Model for Stochastic Demand of Machined Products

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Applied Mathematics 2018年第12期9卷 1395-1423页

作者： Francisco G. Pantoja Victor Songmene jean-pierre kenné Oluwole A. Olufayo Michael Ayomoh Mechanical Engineering Department école de Technologie Supérieure (éTS) Montreal Canada Industrial and Systems Engineering Department University of Pretoria Pretoria South Africa

Cutting tool management in manufacturing firms constitutes an essential element in production cost optimization. In order to optimize the cutting tool stock level while concurrently minimizing production costs, a cost optimization model which considers machining parameters is required. This inclusive modeling consideration is a major step towards achieving effectiveness of cutting tool management policy in manufacturing systems with stochastic driven policies for tool demand. This paper presents a cost optimization model for cutting tools whose utilization level is assumed to be optimized in respect of the machining parameters. The proposed cost model in this research incorporated the effects of diversified machining costs ranging from operational through machining, shortage, holding, material and ordering costs. The machining of parts was assumed to be a single cutting operation. Holt-Winters forecasting technique was used to create a stochastic demand dataset for a test scenario in the production of a high-end automotive part. Some numerical examples used to validate the developed model were implemented to illustrate the optimal machining and tool inventory conditions. Furthermore, a sensitivity analysis was carried out to study the influence of varying production parameters such as: machine uptime, demand and cutting parameters on the overall production cost. The results showed that a desired low level of tool storage and holding costs were obtained at the optimal stock levels. The machining uptime had a significant influence on the total cost while tool life and cutting feed rate were both identified as the most influential cutting variables on the total cost. Furthermore, the cutting speed rate had a marginal effect on both costs and tool life. Other cost variables such as shortage and tool costs had significantly low effect on the overall cost. The output trend showed that the feed rate is the most significant cutting parameter in the machining operation, henc

关键词： Inventory Tool Cost Optimization High Value Product Stochastic Demand Machining Parameters

Effect of the Variable B-Field on the Dynamic of a Central Electron Spin Coupled to an Anti-Ferromagnetic Qubit Bath

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World Journal of Condensed Matter Physics 2012年第4期2卷 246-256页

作者： Martin Tchoffo Georges Collince Fouokeng Siaka Massou Ngwa Engelbert Afuoti Issofa Nsangou Lukong Cornelius Fai Alex Ghislain Tchouadeu jean-pierre kenné De- partment of Physics Faculty of Sciences and Technics University of Abomey-Calavi Cotonou Benin Department of Mechanical Engineering Laboratory of Integrated Production Technologies University of Québec Québec Canada Department of Physics Laboratory of Mesoscopic and Multilayer Structures University of Dschang Dschang Cameroon Department of Physics Laboratory of Mesoscopic and Multilayer Structures University of Dschang Dschang Cameroon Department of Thermal Engineering and Energetics Douala University Institute of Technology Douala Cameroun

This present issue is an extension of the work of Y. Xiao-Zhong et al. who investigated the influence of constant external magnetic field on the decoherence of a central electron spin of atom coupled to an anti-ferromagnetic environment. We have shown in this work that the character variability of the field induces oscillations amongst the eigen modes of the environment. This observation is made via the derivation of the transition probability density of state, a manner by which critical parameters (parameters where transition occur) of the system could be obtained as it shows resonance peak. We equally observed that the two different magnons modes resulting from the frequency splitting via the application of the time-varying external B-Field, exhibit each a resonant peak of similar amplitude at different temperature ranges. This additional information shows that the probability for the central spin system to remain in its initially prepared diabatic state is enhanced for some temperature ranges for the corresponding two magnon modes. Hence, these temperature ranges where the probability density is maximum could save as decoherence free environment;an important requirement for the implementation of quantum computation and information processing in solid state circuitry. The theoretical and numerical results presented for the decoherence time and the probability density are that of a decohered central electron spin coupled to an anti-ferromagnetic spin bath. The theory is based on a spin wave approximation and on the density matrix using both transformations of Bloch, Primakov and Bogoliobuv in the adiabatic limit.

关键词： Decoherence Spin Wave Anti-Ferromagnetic Environment Central Spin Variable B-Field

Foreword to the special section on synchronous programming

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Frontiers of Computer Science 2013年第5期7卷 595-597页

作者： jean-pierre TALPIN INRIA Rennes-Bretagne-Atlantique Rennes 35042 France

1 Introduction Embedded systems are ubiquitous. In applications ranging from avionics, automotive, and industrial process control all the way to the handheld personal digital assistants （PDAs）, cell phones, and bio-...

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Evidence of a Light-Sensing Role for Folate in Arabidopsis Cryptochrome Blue-Light Receptors

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Molecular Plant 2008年第1期1卷 68-74页

作者： Nathalie Hoang jean-pierre Bouly Margaret Ahmad Universite Paris Vl Casier 156 4 Place Jussieu 75005 Paris France Penn State University 25 Yearsley Mill Road Media PA 19063 USA

Arabidopsis cryptochromes cry1 and cry2 are blue-light signalling molecules with significant structural similarity to photolyases-a class of blue-light-sensing DNA repair enzymes. Like photolyases, purified plant cryptochromes have been shown to bind both flavin and pterin chromophores. The flavin functions as a light sensor and undergoes reduction in response to blue light that initiates the signalling cascade. However, the role of the pterin in plant cryptochromes has until now been unknown. Here, we show that the action spectrum for light-dependent degradation of cry2 has a significant peak of activity at 380 nm, consistent with absorption by a pterin cofactor. We further show that cry1 protein expressed in living insect ceils responds with greater sensitivity to 380 nm light than to 450 nm, consistent with a light-harvesting antenna pigment that transfers excitation energy to the oxidized flavin of cry1. The pterin biosynthesis inhibitor DHAP selectively reduces cryptochrome responsivity at 380 nm but not 450 nm blue light in these cell cultures, indicating that the antenna pigment is a folate cofactor similar to that of photolyases.

关键词： a Light-Sensing Role for Folate Arabidopsis Cryptochrome Blue-Light Receptors

Useful zero friction simulations for assessing MBS codes Pascal’s formula giving wheelsets frequency for zero wheel-rail friction

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Theoretical & Applied Mechanics Letters 2022年第3期12卷 145-155页

作者： jean pierre Pascal Pascal Coding Rue d’ErquyPleneuf-Val-Andre F-22370France

Present study provides a simple analytical formula,the“Klingel-like formula”or“Pascal’s Formula”that can be used as a reference to test some results of existing railway codes and specifically those using rigid *** develops properly the 3D Newton-Euler equations governing the 6 degrees of freedom(DoF)of unsuspended loaded wheelsets in case of zero wheel-rail friction and constant ***,by solving numerically these equations,we got pendulum like harmonic oscillations of which the calculated angular frequency is used for assessing the accuracy of the proposed formula so that it can in turn be used as a fast practical target for testing multi-body system(MBS)railway *** to the harmonic property of these pendulum-like oscillations,the squareω2 of their angular frequency can be made in the form of a ratio K/M where K depends on the wheelset geometry and load and M on its *** on K and M are useful to understand wheelsets *** analytical formula is derived from the first order writing of full trigonometric Newton-Euler equations by setting zero elastic wheel-rail penetration and by assuming small *** trigonometric equations are numerically solved to assess that the formula providesω2 inside a 1%accuracy for usual wheelsets *** decreasing the conicity down to 1×10^(−4) rad,the relative formula accuracy is under 3×10^(−5).In order to test the formula reliability for rigid contact formulations,the stiffness of elastic contacts can be increased up to practical rigidity(Hertz stiffness×1000).

关键词： Unsuspended wheelsets Klingel formula Rigid contact Harmonic oscillation Multi body system railway codes Code validation

Pozzolanic reactivity of silico-aluminous fly ash

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Particuology 2008年第2期6卷 93-98页

作者： pierre Adamiec jean-Charles Benezet Ali Benhassaine Ecole des Mines d'Alès 6 Avenue de Clavières30319 ALES CedexFrance

For some years it has been possible to control the particle size of fly ashes, by-products of thermal power stations. Incorporating these very fine particles （obtained by grinding and/or pneumatic selection） improves the physical-mechanical characteristics of mortars and concretes. In this study, we measured the lime consumption of the various fractions （granulometric and densimetric） and identified by X-ray diffraction the neoformed phases by the pozzolanic reaction, to show that it is not sufficient to simply define the pozzolanicity of products based on lime consumption since it does not take into account the nature of the phases formed. The size of the particles used in the test samples also has a determining effect on the quantity of lime consumed. Before comparing results, it is necessary to ensure that the size of the particles （of the global ash and its constituents） be the same. Two distinct neoformed ohases appear： CSH in the largest granular fractions （d〉 40 μm） and C3AH6 in the smaller fractions.

关键词： Fly ash Pozzolanic reaction Particle size