Using simulation optimization for parts recovery and spare parts inventory management in post product life cycle

Surendra M. Gupta — Wed, 16 Dec 2009 15:45:36 PST

The parts recovered from discarded and end-of-life products can be used as a source of spare parts during post product life cycle. However, accurate determination of the final order quantity is complicated as it requires the prediction of spare parts demand for the post product life cycle. In this paper, the spare parts problem is solved using simulation. Simulation is chosen because of the stochastic and complex nature of the problem. A simulation model of the manufacturing system is first developed which is then integrated with a genetic algorithm to determine the optimal final order quantities for a number of...

Use of data envelopment analysis for product recovery

Nuriye Elif Kongar — Wed, 16 Dec 2009 15:45:35 PST

The latest enhancements in industrial technologies, especially the ones in electronics industry, have provided organizations with the ability to manufacture faster and more economical products. This fact, coupled with the growing interest and demand for the latest technology, have led electronic equipment manufacturers to start producing ""high-tech"" and ""personalized"" products at an increasing rate. This has led to a high rate of obsolescence for electronic products worldwide, even though the majority of these ""obsolete"" products still function. In this paper, we investigate a product recovery facility where the end-of-life (EOL) products are taken back from the last users and are...

Use of flexible kanban for material flow control in a disassembly process

Surendra M. Gupta — Wed, 16 Dec 2009 15:45:35 PST

Disassembly is one of the proposed solutions to the increased environmental problem of large-scale disposal of manufactured products. Disassembly process brings with it a lot of unresolved material control issues. In this paper we illustrate the implementation of the recently developed Flexible Kanban System to cope with the uncertainties that are unique to the disassembly system.

Uninformed and probabilistic distributed agent combinatorial searches for the unary NP-complete disassembly line balancing problem

Surendra M. Gupta — Wed, 16 Dec 2009 15:45:34 PST

Disassembly takes place in remanufacturing, recycling and disposal, with a line being the best choice for automation. The disassembly line balancing problem seeks a sequence which: is feasible, minimizes workstations, and ensures similar idle times, as well as other end-of-life specific concerns. Finding the optimal balance is computationally intensive due to exponential growth. Combinatorial optimization methods hold promise for providing solutions to the disassembly line balancing problem, which is proven here to belong to the class of unary NP-complete problems. Probabilistic (ant colony optimization) and uninformed (H-K) search methods are presented and compared. Numerical results are obtained using a recent...

Uncertainty and back-ordering in multi-level product structures

Surendra M. Gupta — Wed, 16 Dec 2009 15:45:34 PST

The influence of uncertainty on the performance of Material Requirements Planning (MRP) systems has been the focus of several studies. All of these studies have incorporated non back-order lot sizing rules. However, attention has been recently directed to back-order lot sizing rules. This paper considers the impact of the presence of both supply and demand uncertainties on the performance of MRP systems in an environment where back-orders are planned. The word reported here is based on a simulation study involving a variety of supply and demand conditions. The study establishes the significance of product structure shape and variant, lot sizing...

Total quality management (TQM) in a reverse supply chain

Surendra M. Gupta — Wed, 16 Dec 2009 15:45:33 PST

Six-Sigma is a newer version of Total Quality Management (TQM), and its fundamental principle is to reduce defects in processes. The traditional approach to calculate the value of n for an n-sigma process can be confusing to prospective six-sigma practitioners, because the three values of interest (viz., process capability ratio, process capability index, and n) are always different. In this paper, we present a new formula that is less confusing, and yet serves the purpose of checking how good a given process is. We apply this formula for a crucial issue (selection of potential recovery facilities) identified in the literature...

The effect of sudden server breakdown on the performance of a disassembly line

Surendra M. Gupta — Wed, 16 Dec 2009 15:45:33 PST

Product and material recovery relies on the disassembly process to separate target components or materials from the end-of-life (EOL) products. Disassembly line is especially effective when products in large quantity are disassembled. Unlike an assembly line, a disassembly line is more complex and is subjected to numerous uncertainties including stochastic and multi-level arrivals of component demands, stochastic arrival times for EOL products, and process interruption due to equipment failure. These factors seriously impair the control mechanism in the disassembly line. A common production control mechanism is the traditional push system (TPS). TPS responds to the aforementioned complications by carrying substantial...

Supplier selection in a closed-loop supply chain network: an ANP-goal programming based methodology

Surendra M. Gupta — Wed, 16 Dec 2009 15:45:32 PST

Traditionally, in supply chain literature, the supplier selection problem is treated as an optimization problem that requires formulating a single objective function. However, not all supplier selection criteria can be quantified, as a result of which, only a few quantitative criteria are included in the problem formulation. To this end, in this paper, we develop an integrated analytic network process (ANP) and preemptive goal programming (PGP) based multi-criteria decision making methodology to address the qualitative and quantitative criteria that influence the supplier selection problem in a closed-loop supply chain network (CLSC). While the ANP methodology aids in determining qualitatively the...

The effect of machine breakdown on the performance of a JIT system

Surendra M. Gupta — Wed, 16 Dec 2009 15:45:32 PST

In this paper, we present the results of a newly developed Kanban system that systematically manipulates the number of Kanbans to cope with the interruptions introduced by machine breakdowns. We illustrate that the performance of this new system is superior to the traditional Kanban system in such an environment.

Supplier selection in a closed-loop supply chain network

Surendra M. Gupta — Wed, 16 Dec 2009 15:45:31 PST

The growing interest in reverse logistics has many reasons, of which, consumers and governments concerns for environment being the primary reason. The growing desire of customers to acquire the latest technology, along with the rapid technological development in every industry, has led to a new environmental problem: waste, consisting of both end-of-life products and used products (products that are discarded prematurely). Increased consumption results in increased use of raw material and energy, thereby depleting the finite natural resources of the world. This environmental degradation is not sustainable by the eco-system of the earth. This environmental issue, in addition to government...

Sudden material handling system breakdown in a disassembly line

Surendra M. Gupta — Wed, 16 Dec 2009 15:45:31 PST

In this paper we study the effect of the sudden breakdown of material handling equipment on the performance of recently introduced MKSD (Modified Kanban System for Disassembly). We also study behavior of a newly developed JIT system for disassembly called DKSDL (Dynamic Kanban System for Disassembly Line) under the same conditions. DKSDL dynamically adjusts the number of disassembly production kanbans in or der to offset blocking and starvation caused by these factors during a disassembly cycle. We compare the overall performances of the MKSD and the DKSDL models under different scenarios. The scenario settings, approach to the solution, results and...

Strategic and tactical planning of a closed-loop supply chain network under uncertainty

Surendra M. Gupta — Wed, 16 Dec 2009 15:45:30 PST

While the strategic planning of a supply chain, which is typically a long range planning, deals with the design aspect of the supply chain (what products should be processed/produced in what facilities etc.), tactical planning is typically a medium-range planning that involves the optimization of flow of goods and services across the supply chain. In this paper, we present a multi-criteria optimization model for the strategic and tactical planning of a closed-loop supply chain under uncertainty, where the aspiration levels for various goals are more likely to be in the approximately more/less than and/or more/less is better form. We use...

Stochastic and deterministic combinatorial optimization solutions to an electronic product disassembly flow shop

Surendra M. Gupta — Wed, 16 Dec 2009 15:45:30 PST

Disassembly takes place in remanufacturing, recycling and disposal, with a flow shop being the best choice for automation. The disassembly line balancing problem seeks a sequence which: is feasible, minimizes workstations, and ensures similar idle times, as well as other end-of-life specific concerns. Finding the optimal balance is computationally intensive due to exponential growth. Combinatorial optimization methods hold promise for providing solutions to the problem, which is proven NP-hard. Stochastic (genetic algorithm) and deterministic (greedy/hill-climbing hybrid heuristic) methods are presented and compared. Numerical results are obtained using a recent electronic product case study.

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Substitution policies for a hybrid system

Surendra M. Gupta — Wed, 16 Dec 2009 15:45:30 PST

As a consequence of environmental necessities, reuse of products has recently become an important issue for production and planning. Many companies are involved in retrieving used products, where they repair, refurbish and upgrade the products in order to sell them for profit. However, the regulations for many markets do not allow manufacturers to sell remanufactured products under the same pretence as new products. Therefore, companies are forced to differentiate both the recovery and the sales activities for the remanufactured products from that of the new products. In this paper, we study the impact of this differentiation. We particularly look at...

Solving a disassembly-to-order system by using genetic algorithm and weighted fuzzy goal programming

Surendra M. Gupta — Wed, 16 Dec 2009 15:45:29 PST

In this paper, Genetic Algorithm (GA) is used to solve the disassembly-to-order (DTO) problem. DTO is a system where a variety of returned products are disassembled to fulfill the demand for specified numbers of components and materials. The main objective is to determine the optimal number of take-back EOL (end-of-life) products for the DTO system which satisfy the desirable criteria of the system. We implement the Weighted Fuzzy Goal Programming (WFGP) to calculate the fitness values in GA process. We also consider product deterioration which affects the yield rates (e.g., older products tend to have lower yield rates for usable...

Solving disassembly sequence planning problems using combinatorial optimization

Surendra M. Gupta — Wed, 16 Dec 2009 15:45:29 PST

Disassembly activities take place in various recovery operations including remanufacturing, recycling, and disposal. The disassembly line is the best choice for automated disassembly of returned products, a feature that will be become crucial in the future. It is, therefore, important that the disassembly line be designed and balanced so that it works as efficiently as possible. However, finding the optimal balance is computationally intensive with exhaustive search quickly becoming prohibitively large, even for relatively small products. In this paper, we solve the disassemb ly line balancing problem using combinatorial optimization techniques, which are instrumental in obtaining near-optimal solutions to problems...

Simulation based approach for return packaging systems

Surendra M. Gupta — Wed, 16 Dec 2009 15:45:28 PST

In this paper, we investigate the effect of different dispatching rules and the vehicle assignment schemes applied to a returnable packaging system in order to provide superior customer satisfaction. The investigation is conducted by a simulation approach, using a commercial software ARENA. The simulation results show that different combinations of dispatching rules and the vehicle assignment schemes affect the customer satisfaction levels differently.

Simulation study on vehicle dispatching strategies for returnable transport packaging

Sagar V. Kamarthi — Wed, 16 Dec 2009 15:45:28 PST

Returnable transport packaging plays an important role in facilitating the transfer of a large volume of products in a close-loop distribution network. To make effective use of returnable transport packaging, vehicle dispatching strategies are crucial. With an appropriate vehicle dispatching strategy, for example, a fast turnover time and a short waiting time for packaging dispatch can be achieved. However, there are some factors that directly influence vehicle dispatching strategies. These factors include the arrival demand fluctuations, the availability of serving vehicles, and the geographic proximity of the facility to the customer's locations. In this study, authors investigate the effect of...

Selection of collection centers for reverse logistic networks

Onder Ondemir — Wed, 16 Dec 2009 15:45:27 PST

In this paper, we address the problem of locating collection centers for a company that collects used products from product holders. Each product holder has an inherent willingness to return the product, and makes the decision on the basis of financial incentive offered by the company. We present a mixed-integer nonlinear facility location-allocation model to find the optimal locations, the optimal incentive values for different product types and the optimal vehicle type. Because the problem is NP-complete, a heuristic method is proposed to solve medium and largesize instances. We experiment with location dependent transportation costs which reflect the road conditions...

Sensor-embedded computers for better life-cycle management

Sagar V. Kamarthi — Wed, 16 Dec 2009 15:45:27 PST

This research investigates the advantages offered by embedded sensors for cost-effective and environmentally benign product life cycle management for desktop computers. During their use by customers as well as at the end of their lives, Sensor Embedded Computers (SECs) by virtue of sensors embedded in them generate data and information pertaining to the conditions and remaining lives of important components such as hard-drive, motherboard, and power supply unit. A computer monitoring framework is proposed to provide more customer comfort, reduce repair costs and increase the effectiveness of current disassembly practices. The framework consists of SECs, remote monitoring center (RMC), repair/service,...