فهرست مطالب

  • Volume:6 Issue: 4, 2019
  • تاریخ انتشار: 1398/08/10
  • تعداد عناوین: 7
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  • Reza Ahmadi * Pages 282-295
    Based on a copula function this paper addresses a maintenance scheduling problem for parallel systems whose components are dependent and their failures are detected only by inspections. To carry out preventive maintenance actions, the decision process is steered by the excursions of the state process X(t) describing the total number of failed components up to age t. Since both the maintenance costs and the level of maintenance are driven by the inspection interval τ and the preventive replacement threshold j, using the standard renewal theory arguments, the paper aims to jointly determine both optimal inspection and optimal replacement policy which truly balances two factors. The model is examined for the case when the dependence structure is modelled by the FGM copula function and the marginal lifetime distribution of components conforms to a Weibull distribution. Further, a sensitivity analysis is performed to examine some important features of the model's parameters. We will see the unified framework developed not only generalizes age replacement policy and other classic maintenance models, but also allows considerable flexibility such that different scenarios can be explored.
    Keywords: Inspection, Maintenance, Replacement, Hidden failures, Copula function, Renewal reward theorem
  • Abu Md Mashud *, Md Rakibul Hasan Pages 296-314
    An inventory model is proposed with consideration of price, frequency of advertisement, continuous time and partially backlogged shortages for instantaneous decaying products. The deterioration is considered as instantaneous i.e., when the item stock in retailer’s house immediately deterioration will start with a constant rate for a certain period. If there are any shortages allowed, then it is partially backlogged. The main objective of this paper is to find the optimal cycle length (T) and the period where deterioration occurred (td) in order to minimize the total cost (TC) of the inventory system. The corresponding inventory problem constitutes a nonlinear constraint optimization problem. Here this problem is solved by using Lingo 15 software and also give a 3D graph with the help of MATLAB2017a to show the convexity of the objective function. Finally, to illustrate and validate the inventory model, a numerical example is considered with some realistic data. A sensitivity analysis is carried out to investigate the effect of changes of different inventory parameters, changing one parameter at a time and keeping the others value of parameters is same.
    Keywords: Inventory, constant deterioration, partially backlogged shortages, Price Dependent Demand, continuous time, frequency of advertisement
  • Debadyuti Das *, Kalpesh Madhukar Bonde Pages 315-333

    The present study has developed an integrated framework for handling a facility relocation problem by combining quantitative modelling methodology with the factor rating technique. It has demonstrated the framework with reference to a real case of a corrugated box manufacturing plant. The first phase of the integrated framework involves evaluation of supply chain cost including inbound logistics cost, in-plant operations cost, and outbound logistics cost of the existing location and two other candidate locations. A mixed integer linear programming model was formulated to reflect the above problem. Sensitivity analyses were also carried out on different parameters in order to test the behaviour of the model in respect of total cost. The second phase involves evaluation of both quantitative and qualitative factors across all three locations by a team of experts on a common scale. The outcome of the first phase expressed in terms of quantitative elements of cost enabled the experts to suitably evaluate the candidate locations on cost dimension on the common scale. Finally, the composite score is computed for all three locations which aids location planners in making a realistic comparison among the three locations. Towards the end, managerial implications of the findings are discussed.

    Keywords: Facility Relocation, Integrated Framework, Mixed integer linear programming, Factor Rating
  • Jafar Bagherinejad *, Somayeh Najafi Ghobadi Pages 334-348

    In this study, we propose a model to minimize the inventory and location costs of a supply chain, including a production plant, warehouses and retailers. The production plant distributes a single product to retailers through warehouses. The model determines the location of warehouses, allocates retailers to the warehouses and indicates the length of order intervals at warehouses and retailers. To ensure the order quantity is lower than the warehouses’ capacity, we consider the capacity constraints. Unlike the exciting researches, we investigate the limitation on the number of established warehouses. We formulize the problem as a nonlinear mixed-integer model and propose two efficient meta-heuristic algorithms including a genetic algorithm (GA) and an evolutionary simulated annealing algorithm (ESA) to solve it. To improve the proposed algorithms, in generating populations, a new heuristic method which produces feasible solutions is designed. The Taquchi method is used for tuning the parameters of the proposed algorithms. The small size numerical examples are solved and sensitivity analysis is done to demonstrate the influential theoretical results. We evaluate the proposed algorithms by comparing the solutions of them with the optimal solution obtained by the Lingo 11. Further, we investigate the efficiency of the proposed algorithms by solving numerical examples in different sizes and depict the percentage gaps between the best solution values and the average objective values of them. Results reveal that both the GA and ESA are efficient for solving the proposed model, but the ESA outperforms the GA on the optimal solution, computing time and stability.

    Keywords: Location, Inventory, limited capacity, Genetic Algorithm, Evolutionary simulated annealing
  • Naeme Zarrinpoor * Pages 349-359
    This paper aims to propose a multi-period multi-product supply chain network design which takes the sustainability dimensions into consideration in both strategic and operational decisions. Several critical issues in the planning of supply chain networks are considered in the model such as the capacity of facilities, the minimum acceptable rate for the social score of manufacturing plants and distribution centers, the maximum coverage radius, and the limited budget availability. In order to obtain an effective and efficient network design, different categories of uncertainty are also considered, including the provider-side uncertainty reflected in the capacity of constructed facilities, as well as the economic, environmental, social, and technical parameters, the receiver-side uncertainty reflected in the demand, and the in-between uncertainty reflected in the transportation costs and the maximum coverage radius. To deal with different sources of uncertainty in the concerned problem, a chance constrained fuzzy programming approach is employed. Several test problems are used to analyze the characteristics of the proposed problem. The computational results can help decision makers to design supply chain networks from economic, environmental, and social perspectives.
    Keywords: Supply Chain Management, Network design, Sustainability, Uncertainty, Coverage radius, Chance constraint fuzzy programming
  • Yahia Zare Mehrjerdi *, Reza Lotfi Pages 360-388
    The design of a resilient and sustainable supply chain network is a prolific field to be studied academically, which can potentially develop and affect supply chain performance. The innovation of this research is a closed-loop supply chain network by taking the sustainability, resilience, robustness, and risk aversion approach into consideration. A two-stage, mixed-integer linear programming is used for modeling and a robust counterpart model is utilized to encounter the demand uncertainties. The Conditional Value-at-Risk criterion is considered to model risk and compared with Value-at-Risk and average absolute deviation. Sustainability goals addressed in this research include minimizing the costs, CO2 emission, and energy, and maximizing the employment. The case study in this research is an automobile assembly company that has decided to set up a supply chain network. The LP-Metric method is applied to merge objectives and NEOS server is employed to attain an optimal solution in large scale. The constraint relaxation and fix-and-optimize are employed to produce the upper and lower bounds in medium and large scale. The results showed that the proposed model provides a better estimation of the total cost, pollution, energy consumption, and employment level compared to the basic model.
    Keywords: Closed-loop supply chain, Sustainability, Resilience, Risk
  • Larysa Vasyurenko *, Ihor Kuksa, Valerii Danylenko Pages 389-394
    On the basis of the conducted analysis of the current framework of the professional standards of a higher education specialist in Australia and the United Kingdom there was determined the purpose of the study to substantiate the methodological principles for streamlining the attribution of the determination of the level of professional competence of a specialist in the field of higher education with the outline of the foundation descriptors in the context of the public management of the organization of remuneration. There were interpreted the basic principles and outlined distinctive-similar features in the presented standards; there was proposed the universalized construction of the mechanism of professional standard functioning with the use of a competency-based approach, that was generalized by the addition of the own term "personal professional effect" (PPE); there was presented the essence of the proposed term PPE in the form of a mathematical formula, which generalizes the purpose and tools for its achievement.
    Keywords: Management, Higher Education, State administration, Competence, Organization of remuneration, Professional standard