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A fuzzy model for shortage planning under uncertainty due to lack of homogeneity in planned production lots

APPLIED mathematical modelLING 2015年第15期39卷 4463-4481页

作者： Alemany, M. M. E. Grillo, Hanzel Ortiz, A. Fuertes-Miquel, Vicente S. Univ Politecn Valencia Res Ctr Prod Management & Engn CIGIP E-46022 Valencia Spain Univ Politecn Valencia Dept Ingn Hidraul & Medio Ambiente E-46022 Valencia Spain

Lack of homogeneity in the product (LHP) affects several sectors like horticulture, reverse logistics, furniture, ceramics and leathers, among others. Productive processes with LHP are characterized by manufacturing units of the same finished good (FG) with certain attributes that differ and are relevant to customers. This aspect leads to the existence of different subtypes of the same FG in each production lot, which provides homogeneous sublots. Due to inherent LHP uncertainty, the size of each homogeneous sublot is not known until produced. LHP becomes a problem when customers order several units of the same FG and require homogeneity among them;i.e., being served with the same subtype. Like inherent LHP uncertainty, discrepancies between planned homogeneous quantities and the real ones is quite usual. This means it is impossible to serve committed orders with the previously defined requirements of quantity, homogeneity and due date, which brings about a shortage situation. In this paper, a fuzzy mixed integer linear programming model is proposed to support shortage planning in environments with LHP (LHP-FSP model). The LHP-FSP model aims to maximize the profits of served orders by reallocating the quantities of subtypes in stock and the uncertainty future ones in the master plan among the already committed orders. One of the main contributions of the paper is to model the fuzzy interdependent coefficients that represent the fraction of each homogeneous sublot. Finally, experiments based on realistic data from a ceramic company have been designed to validate the model and to analyze its behavior in different scenarios. (C) 2014 Elsevier Inc. All rights reserved.

关键词： Fuzzy mathematical programming model Shortage planning Order promising Lack of homogeneity in the product Uncertainty

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An algorithmic approach to generate timesharing schemes for multi-period HEN designs

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CHEMICAL ENGINEERING RESEARCH & DESIGN 2015年 93卷 402-410页

作者： Jiang, Da Chang, Chuei-Tin E China Univ Sci & Technol Key Lab Adv Control & Optimizat Chem Proc Minist Educ Shanghai 200237 Peoples R China Natl Cheng Kung Univ Dept Chem Engn Tainan 70101 Taiwan

Without changing the conceptual configuration of a given multi-period HEN design, it has been shown in this work that the total capital cost can be significantly reduced by allowing a chosen set of exchangers to be shared by more than one match in different periods. Systematic synthesis strategies have been developed to generate the timesharing schemes needed for realizing this novel idea. The proposed strategies can be implemented either with generic area allocation algorithms or by solving a MINLP model. The former approach is not only easy to use but also effective for creating practical solutions which are near optimal. Somewhat better results may be obtained by using the latter method with considerably larger computation effort. Based on the extensive case studies performed so far, it was found that both approaches are applicable for generating the timesharing schemes that achieve significant saving in capital investment. (C) 2014 The Institution of Chemical Engineers. Published by Elsevier B.V. All rights reserved.

关键词： Heat exchanger network Multi-period design Timesharing scheme mathematical programming model Area allocation MINLP model

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Strategic and tactical mathematical programming models within the crude oil supply chain context-A review

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COMPUTERS & CHEMICAL ENGINEERING 2014年 68卷 56-77页

作者： Sahebi, Hadi Nickel, Stefan Ashayeri, Jalal Karlsruhe Inst Technol Dept Econ & Management D-76131 Karlsruhe Germany Iran Univ Sci & Technol Dept Ind Engn Tehran *** Iran Tilburg Univ Tilburg Sch Econ & Management NL-5000 LE Tilburg Netherlands

In today's business world, oil companies cannot be productive and competitive, and thus, will not survive without taking the supply chain management concepts into account. Consequently, the management of a crude oil supply chain (COSC) is increasingly receiving substantial importance. The growing number of papers and books on this topic is a further witness of this fact. To foster insight into issues intertwined with COSC problems, this paper is devoted to an extensive review of mathematical programming models in this context. The classification approach for this review is based on a taxonomy framework. In this framework, ongoing and emerging challenges surrounding the strategic and tactical decisions of COSC problems are investigated. As a main goal, the gaps of literature are analyzed to recommend possible research directions. (C) 2014 Elsevier Ltd. All rights reserved.

关键词： Crude oil supply chain Strategic and tactical decisions mathematical programming model Literature review

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A stochastic model for operating room unique equipment planning under uncertainty 15

A stochastic model for operating room unique equipment plann...

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15th IFAC Symposium on Information Control Problems in Manufacturing

作者： Razmi, J. Yousefi, M. S. Barati, M. Univ Tehran Coll Engn Sch Ind Engn Tehran Iran Malek & Ashtar Univ Technol Dept Mech Engn Shahinshahr Isfahan Iran

In the present economic context, the operating theatre is considered as a critical activity in health care management. This paper describes a model for Operating Room (OR) planning under constraint of a unique equipment. At first level we schedule elective surgeries under the uncertainty of using a unique equipment. At the second level we consider emergency surgeries, and at the third level a coefficient factor for surgeons is introduced in using this unique equipment. A new mathematical programming model is first proposed and at the second and third level, a new stochastic mathematical programming model is proposed Lingo is used as an exact approach. because of NP-hardness a Metaheuristic approach (Differential Evolution (DE)) is proposed for large size problems. (C) 2015, IFAC (International Federation of Automatic Control) Hosting by Elsevier Ltd. All rights reserved.

关键词： mathematical programming model unique Equipment Operating rooms Surgery planning Differential Evolution (DE) Sample Average Approximation (SAA)

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User Oriented Approach to Website Navigation Concept Using mathematical model 7

User Oriented Approach to Website Navigation Concept Using M...

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7th International Conference on Computational Intelligence and Communication Networks (CICN)

作者： Thorat, Shalaka S. More, Priyanka GS Moze Coll Engn Dept Comp Engn Pune 411045 Maharashtra India

ISBN: (纸本)9781509000760

Web sites are most effective when they meet both the contents and usability needs of their users. Due to tremendous growth of web application, it increases the complexity of web applications and web navigation. Website design is easy task but, to navigate user efficiently is big challenge, one of the reason is user behavior is keep changing and web developer or designer not think according to user's behavior. Designing well-structured websites to facilitate effective user navigation patterns has long been a challenge in web usage mining with various applications like navigation prediction and improvement of website management. Different methods have been proposed to reorganize WebPages to improve users navigation using users navigation data but it still causes disorienting users and increases user's cognitive load. There is a need to improve the efficiency and the performance of a website for effective user navigation. Through this Paper we will propose mathematical programming model to improve user navigation while minimizing alteration to current structure. Optimal solution can be very quickly obtained. We are minimizing unnecessary changes to the present structure of a Web site and hence can be applied for Web site maintenance on a regular basis.

关键词： mathematical programming model mini session Path threshold user navigation web mining

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A stochastic model for operating room planning under uncertainty and equipment capacity constraints

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Journal of Industrial Engineering International 2015年第2期11卷 269-279页

作者： Razmi, J. Barati, M. Yousefi, M.S. Heydari, J. School of Industrial Engineering College of Engineering University of Tehran Tehran Iran Department of Mechanical Engineering Malek e Ashtar University of Technology Shahin Shahr Isfahan Iran

In the present economic context, the operating theater is considered as a critical activity in health care management. This paper describes a model for operating room (OR) planning under constraint of a unique equipment. At first level we schedule elective surgeries under the uncertainty of using a unique equipment. At the second level we consider emergency surgeries, and at the third level a coefficient factor for surgeons is introduced in using this unique equipment. The planning problem consists in scheduling a unique equipment and assigning elective cases to different periods over a planning horizon to minimize the sum of elective patient related costs and overtime costs of ORs. The most important factor that we have focused on this paper is equipment resource constraint. A new mathematical programming model is first proposed and at the second and third level, a new stochastic mathematical programming model is proposed. Then sample average approximation is presented to approximate the problem with sample size N and then Lingo is used as an exact approach. Because of NP-hardness, exact method does not work for large size problems, so a Metaheuristic approach (differential evolution) is proposed for large size problems. Numerical results show that important gains (approximately 3.5 % in overall cost) can be realized by this stochastic OR planning model. © The Author(s) 2015.

关键词： Differential evolution (DE) mathematical programming model Operating rooms Sample average approximation (SAA) Surgery planning Unique equipment

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Two-step mathematical programming synthesis of pinched and threshold heat-integrated water networks

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JOURNAL OF CLEANER PRODUCTION 2014年 77卷 116-139页

作者： Ibric, Nidret Ahmetovic, Elvis Kravanja, Zdravko Univ Tuzla Fac Technol Tuzla 75000 Bosnia & Herceg Univ Maribor Fac Chem & Chem Engn SLO-2000 Maribor Slovenia

This contribution describes a novel simultaneous mathematical programming model for the synthesis of pinched and threshold heat-integrated water networks (HIWNs). A two-step solution strategy is proposed consisting of a subsequent solution using two models. Firstly, the nonlinear programming (NLP) targeting model is solved by assuming a given value for the heat recovery approach temperature (HRAT), with the objective of minimising the operating cost of the network. This model provides a good initialisation point and rigorous bounds (freshwater and utilities consumption) for the mixed integer nonlinear programming (MINLP) model solved during the second synthesis step. The solution procedure is repeated for a range of HRAT values providing different initialisations and constraints identifying a set of good locally-optimal solutions. In this study we considered and presented solutions for three types of HIWN problems, namely, pinched in which both utilities are required, threshold in which a hot utility is required, and threshold requiring a cold utility. The obtained results indicate that the proposed mathematical programming model and the solution strategy can be successfully applied to the synthesis of pinched and threshold HIWNs. (C) 2014 Elsevier Ltd. All rights reserved.

关键词： mathematical programming model Heat-integrated water networks Two-step solution strategy Superstructure optimisation

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New Distributed Approach for an Autonomous Dynamic Management of Interdependent Virtual Machines 8

New Distributed Approach for an Autonomous Dynamic Managemen...

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Asia modelling Symposium 2014 8th International Conference mathematical modelling Computer Simulation

作者： Benbrahim, Salah-Eddine Quintero, Alejandro Bellaiche, Martine Ecole Polytech Dept Software Engn Montreal PQ Canada

ISBN: (纸本)9781479964871

This paper, based on the paper [1], presents and develops a mathematical model for a dynamic allocation of virtual distributed resources in a data center using several criteria. This dynamic allocation of resource hosting interdependent applications reduces the response time of distributed applications and their under-utilization. The main contribution of this research is the use of a distributed architecture to manage the movements of interdependent virtual machines which is an interesting solution regarding its scalability, feasibility and flexibility. The results of this paper proposed model show that it is possible to reduce the VM migrations needed to a network load balancing.

关键词： Cloud networks interdependent VM live migration networks (ViMaLMi) mathematical programming model VMs' allocation network planning

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New Distributed Approach for an Autonomous Dynamic Management of Interdependent Virtual Machines 17

New Distributed Approach for an Autonomous Dynamic Managemen...

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International Conference on Network-Based Information Systems (NBiS)

作者： Benbrahim, Salah-Eddine Quintero, Alejandro Bellaiche, Martine Ecole Polytech Dept Software Engn Montreal PQ Canada

ISBN: (纸本)9781479942244

This paper, Based on the paper [1], present and develop a mathematical model for a dynamic allocation of virtual distributed resources in a data center using several criteria. This dynamic allocation of resource hosting interdependent applications reduces the response time of distributed applications and their under-utilization. The main contribution of this research is the use of a distributed architecture to manage the movement of interdependent virtual machines which is an interesting solution regarding its scalability, feasibility and flexibility.

关键词： Cloud networks interdependent VM live migration networks (ViMaLMi) mathematical programming model VMs' allocation network planning

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Real-Time QoS Issues in Live Migration of Interdependent Virtual Machines 8

Real-Time QoS Issues in Live Migration of Interdependent Vir...

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Asia modelling Symposium 2014 8th International Conference mathematical modelling Computer Simulation

作者： Benbrahim, Salah-Eddine Quintero, Alejandro Bellaiche, Martine Ecole Polytech Dept Software Engn Montreal PQ Canada

ISBN: (纸本)9781479964871

This paper, based on papers [1-3], presents and develops a mathematical model to meet the strict QoS constraints of (soft) real-time virtualized distributed applications while their hooting interdependent Virtual Machines (VMs) are undergoing a live migration. To this purpose, it is vital to take simultaneously into account the network resource requirements of a VM live migration, the datacenter SLAs contracts, and the quality of services of migrating interdependent applications. Set of simulations are executed and show that it is possible to respect SLAs contracts in a datacenter and to maintain QoS of interdependent applications while their hosting VMs undergoing live migrations.

关键词： Cloud networks interdependent VM live migration networks (ViMaLMi) mathematical programming model VMs' allocation network planning

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