European J. of Industrial Engineering (18 papers in press)
The impact of online sales in centralized and decentralized dual-channel supply chains
by Subrata Saha
Abstract: This paper studies a supply chain structure featuring two different types of distribution channels through which manufacturers sell products. The centralised and decentralised distribution channels considered in this study are affected by online sales outside the structured channels. In the centralised distribution channel, two retail stores located in geographically distinct markets are operated by a single owner. In the decentralised distribution channel, two retailers independently operate two retail stores. In the non-cooperative scenario, the manufacturer always prefers the decentralised distribution channel irrespective of whether an online channel is used. To achieve channel coordination, a revenue-sharing contract is applied, but it can be used to coordinate only the decentralised distribution system. Therefore, a modified revenue-sharing contract is proposed to coordinate the centralised distribution system. The analytical study reveals that without coordination among the channel members, the manufacturer always earns maximum profit in decentralised distribution systems. However, if the supply chain is coordinated, then the manufacturer receives more benefits from using the centralised distribution systems under certain conditions. Propositions are presented to describe the characteristics of distribution structures, and to provide meaningful management guidelines for coordinating them. Extensive numerical investigations are also presented.
Keywords: Supply chain management; Dual-channel supply chain; Revenue sharing contract; Pricing strategy; Stackelberg.
Design of facility location-allocation network with an emergency backup supply system
by Jae-Dong Hong, Ki-Young Jeong
A hybrid genetic tabu search algorithm for minimizing total completion time in a flexible job shop scheduling problem
by Asma Fekih, Hatem Hadda, Imed Kacem, Atidel B. Hadj-Alouane
A possibilistic model for production planning with uncertain demand
by Maria Laura Cunico, Aldo Vecchietti
A Stochastic Maritime Transportation-Inventory Problem with Gamma, Exponential, and Uniform Demand Distributions
by Hossein. M. Soroush, Salem M. Al-Yakoob, Fatemah A. Alqallaf
A Systematic Literature Review of the Design of Intermodal Freight Transportation Networks Addressing Location-Allocation Decisions
by Anny Del Mar Agamez-Arias, José P. García-Sabater, Angel Ruiz, José Moyano-Fuentes
Abstract: This systematic literature review focuses on planning models jointly addressing location and allocation decisions related to the design of intermodal freight transportation networks. Since this body of literature is evolving quickly, a methodology based on a linked two-stage analysis is proposed. The first stage analyses recent surveys to establish the guidelines and criteria that enable the subsequent systematic review. Then, the review concentrates on analysing contributions to the current state of the art on intermodal freight transportation from two close, yet different research streams: transportation networks and supply chain networks. Key features identified in the first stage such as: 1) the research problems characteristics; 2) the intermodal networks designs particularities; 3) proposed solution techniques, among others, are used to classify and analyse the different contributions. The review identifies current trends, emerging topics and some issues that merit being researched.
Keywords: systematic literature review; SLR; intermodal facilities; network design; location-allocation problem; intermodal freight transport; mathematical programming; modelling; optimisation techniques.
Two-phase differential evolution for solving emergency response supplies optimization problem
by Qi Cao, K.M. Leung, Wenhua Hou
Abstract: A material supply model is constructed for serious disasters in which a large number of supply centers and disaster areas are involved. We introduce a new method referred to as two-phase differential evolution (TPDE) to solve this kind of complex nonlinear programming problem. In constraint handling phase, the goal is to explore the parameter space to identify a feasible solution quickly. In optimum seeking phase, the aim is to gradually improve the quality of current best solution. Different differential evolution schemes and special handling techniques are utilized in the two phases. Extensive numerical optimization experiments are conducted where TPDE is compared with results obtained from using commercial software and three evolutionary optimization methods. We determine that TPDE is always able to find a feasible solution with fewer generations and the optimal solution almost always ranks as the best. This work is beneficial to address large-scale nonlinear optimization problems with constraints.
A material supply model is constructed for serious disasters in which a large number of supply centers and disaster areas are involved. We introduce a new method referred to as two-phase differential evolution (TPDE) to solve this kind of complex nonlinear programming problem. In constraint handling phase, the goal is to explore the parameter space to identify a feasible solution quickly. In optimum seeking phase, the aim is to gradually improve the quality of current best solution. Different differential evolution schemes and special handling techniques are utilized in the two phases. Extensive numerical optimization experiments are conducted where TPDE is compared with results obtained from using commercial software and three evolutionary optimization methods. We determine that TPDE is always able to find a feasible solution with fewer generations and the optimal solution almost always ranks as the best. This work is beneficial to address large-scale nonlinear optimization problems with constraints.
Keywords: evolutionary computation; large-scale optimization; emergency logistics; differential evolution.
A Multi-Objective Approach in Expanding the Pre-positioning Warehouse Networks in Humanitarian Logistics
by Ertan Yakıcı, Mumtaz Karatas, Serhan Duran
Abstract: In this study, we focus on the structure of the pre-positioning warehouse networks which have a great effect on the response to a disaster. We determine the pre-positioning warehouse network configuration of CARE International with a multi-objective approach using the recent decade data. In addition to the minimization of the average response time of an item, we also consider the maximum response time and maximum water delivery time as additional objectives. After analysis of the non-dominated solutions, we conclude that CARE International should open a warehouse in Kenya and pre-position 39-44% of all relief items other than tents to this location while starting to operate the Denmark warehouse instead of the Dubai warehouse.
Keywords: Pre-positioning; Humanitarian Relief Logistics; Warehouse Location; Network Expansion; Multi-Objective.
SCHEDULING IN ROBOTIC CELLS WITH TIME WINDOW CONSTRAINTS
by Wassim Zahrouni, Hichem Kamoun
K-means clustering combined with principa component analysis for material proling in automotive supply chains
by JoãoN.C. Gonçalves, Paulo Cortez, M. .Sameiro Carvalho
Hub location problem with balanced round-trip flows on hub links
by Qing-Mi Hu
Abstract: This paper addresses the classical single and multiple allocation hub location problems with fully interconnected hubs, in which the balanced round-trip flows on hub links are considered in the strategic decision making process. The use of balanced round-trip flows on hub links is motivated by the need to decrease the empty-trip rate of vehicles and increase the full-load rate of vehicles. Mixed-integer programming models are presented for single and multiple allocation versions of the problems. Numerical experiments with the CAB and AP data sets are performed to analyze the impacts of balanced flows on the network configurations and the utilization of service resources. Experimental results show that the number of located hubs tends to decrease with a decrease in the allowable unbalanced round-trip degree of the hub link flows. The utilization rate of transportation resources can be significantly improved with a small increase in the traditional operating cost. Moreover, a better modeling of economies of scale can be achieved when considering balanced flows.
Keywords: hub location; balanced flows; economies of scale; mixed-integer programming.
A New Formulation for the Parallel Machine Order Acceptance and Scheduling Problem with Sequence-Dependent Setup Times, Release Dates and Deadlines
by Papatya Sevgin B?çakc?, Imdat Kara, Tusan Derya
Abstract: Order acceptance and scheduling problem arises when there is limited capacity to process all orders in a make-to-order environment. The paper examines the identical parallel machines order acceptance and scheduling problem with sequence-dependent setup times, release dates and deadlines. The literature of multiple machine form is deeply researched and studies with identical parallel machines are sorted out It is concluded that well-designed mathematical formulations are still necessitated in this area. New formulation considering sequence-dependent setup times is proposed for this problem and a recent formulation is chosen from the literature in order to make the comparison. The problem is also extended to the form with release dates and deadlines which is unique in the literature. An extensive computational analysis is conducted to test the performance of the formulations It is found that our proposed formulation outperformed the existing one in terms of run times and the number of optimal values.
Keywords: Parallel machine Order Acceptance and Scheduling Sequence-Dependent Setup Times Release Dates Mathematical Formulation.
Conservative Profitability Evaluation for a Newsboy-type Product based on Achievable Capacity Index
by Dong-Yuh Yang, Chia-Huang Wu, Rung-Hung Su
Abstract: The achievable capacity index (ACI) can measure the profitability of a newsboy-type product with probabilistic distributed demand. This criterion has been employed to deal with the problem of profitability evaluation by implementing statistical hypothesis testing. However, due to sampling errors, the point estimate of ACI probably overestimates the profitability. To this end, we derive a lower confidence bound of ACI (LCBA) to give a conservative evaluation of profitability. Since the complex sampling distribution of ACI makes it difficult to obtain an explicit closed-form expression of LCBA, we characterize the relationship between LCBA and estimator of ACI under given confidence level and sample size. A computational algorithm is proposed to obtain LCBA. Extensive numerical results of LCBA for various sample sizes, confidence levels and estimates are tabulated. Finally, we illustrate the practicality and applicability of the proposed method in an application example. Some managerial insights are also discussed.
Keywords: Achievable capacity index; conservative profitability evaluation; lower confidence bound; newsboy problem.
Robust optimization to design a dynamic cellular manufacturing system integrating group layout and workers assignment
by Reza Kia, Mohsen Lashgari, Fariborz Jolai
Abstract: In this paper, a robust optimization approach is proposed to solve a mathematical model integrating cell formation, group layout and operators assignment decisions under a dynamic situation. The main aim of applying a robust approach is to obtain an optimal design of a cellular manufacturing system that is robust with respect to encountered uncertainties in part demands and processing times. The integrated model incorporates several design attributes including operations sequence, group layout, equal-area facilities multi-rows layout, flexible cell reconfiguration, operators hiring/firing and training , operator available time, limitations of cell size and uncertain processing times and part demands. Two illustrative numerical examples are solved to investigate the validity of the robust model. Regarding the NP-hardness of the proposed model, an efficient simulated annealing algorithm is implemented. Some test problems either generated randomly or taken from the literature are solved and the results are compared with the ones obtained using CPLEX.
Keywords: Dynamic cellular manufacturing system; robust optimization; group layout; worker assignment; mixed-integer nonlinear program; simulated annealing.
A New Multiobjective-Multicriteria Model for Determining Physical Asset Management Strategy Based on Maintenance and Procurement Factors
by Ali Sayyah, Amin Abbasi-Pooya, Reza Baradaran Kazemzadeh
Abstract: In this research, a new multiobjective-multicriteria model is presented to determine physical asset management strategy for capital equipment. Initially, a multi-objective model is formulated to determine non-dominated strategies considering cost, reliability, and availability as objective functions. Secondly, the strategies will be ranked based on decision maker preferences and restrictions using a PROMETHEE-Entropy module. Each strategy is a vector of procurement variables (dealer-manufacturer and contract type) and maintenance planning variables (PM action level, PM interval, and the degree of upgrade action). The multi-objective model, which is a new nonlinear mixed integer optimization model, is solved using a customized NSGA-II. Buy, lease, rent and upgrading a used equipment are contract types that are considered. The model is used in a real case for determination of asset management strategy for a truck to be used in a mine for 48 months. A piece of software is designed for simplification of using the model.
Keywords: Physical Asset Management; Maintenance Planning; Contract Management; Reliability; Availability; Equipment Management.
Redesigning Multi-echelon Integrated Distribution Networks Using the Lagrangian Relaxation Heuristics
by Hokey Min, Pouyan Nikzad, Farhad Moghadam
Abstract: With constant changes in customer and supplier bases in the midst of rapid globalization and rising e-commerce activities, supply chain professionals need to reassess the existing distribution network more frequently than ever before. Since the supply chain includes a network of suppliers, customers and third-party intermediaries, the problem of redesigning the warehousing facility poses many challenges. To solve that challenging distribution network redesign problem (DNRP), we develop and propose a non-linear optimization model This model takes into account the multi-echelon links and dynamic interdependence among supply chain partners in multiple periods The proposed model was structured in the dynamic knapsack framework where a known quantity of resources is available and demands for those resources arrive randomly over time In this framework, we develop a new heuristic based on the Lagrangian relaxation, sub-gradient, and branch and bound methods for solving the DNRP.
Keywords: Facility network redesign; warehousing; dynamic knapsack problem; risk pooling; Lagrangian relaxation.
Supply Chain Coordination Under Financial Constraints and Yield Uncertainty
by Tao Pang, Hongjun Peng
Abstract: A coordination problem for a supply chain with capital constraints and yield uncertainty is considered in this paper. In order to improve the supply chain, a buyback and risk sharing (BBRS) mechanism is proposed, in which the distributor shares the supplier's yield uncertainty risk by purchasing the overproduced products or waiving the shortage penalty, and the supplier shares the distributor's demand uncertainty risk by buying back the unsold products. The results indicate that, the profits and the strategies under the BBRS are the same with those under the centralized case. In addition, the proposed BBRS mechanism has a built-in mechanism to allocate the spillover profit between the supplier and the distributor. The results also show that the BBRS can increase the production quantity. Finally, we derive the bankruptcy probabilities for both the supplier and the distributor, and the probabilities depend on their initial capitals.
Keywords: Supply Chain Finance; Capital Constraint; Yield Uncertainty; Buyback; Risk Sharing.
Collaboration and sharing in a retailer-led supply chain with yield uncertainty and loss aversion
by Fuyou Huang, Bin Chen, Wenying Xie, Juan He
Abstract: This paper addresses a retailer-led supply chain in which a loss-averse supplier subject to yield uncertainty sells products to a risk-neutral retailer facing stochastic demand. An option contract is introduced to develop collaboration and sharing models to improve channel performance and achieve supply chain coordination. We derive the closed-form solution for the optimal production policy, and show that option contract is a viable alternative to effectively mitigate the serious conflicts between the dominant retailer and the supplier, which leads to a win-win situation and sustainable relationship development. We analyse how the loss-averse behaviour of the supplier affects the production strategy and contract design. Also, we discuss how to share profit between the retailer and the supplier to achieve Pareto-improvement. In addition, we examine the role of option contract for achieving channel coordination and Pareto-improvement under loss aversion and single-side uncertainty.
Keywords: supply chain coordination; Pareto-improvement; option contract; yield uncertainty; loss aversion.