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This paper discusses the design and application of local search methods to a real-life application at a steel cord manufacturing plant. The case study involves a layout problem that can be represented as a Quadratic Assignment Problem (QAP). Due to the nature of the manufacturing process, certain machinery need to be allocated in close proximity to each other. This issue is incorporated into the objective function through assigning high penalty costs to the unfavorable allocations. QAP belongs to one of the most difficult class of combinatorial optimization problems, and is not solvable to optimality as the number of facilities increases. We implement the well-known local search methods, 2-opt, 3-opt and tabu search. We compare the solution performances of the methods to the results obtained from the NEOS server, which provides free access to many optimization solvers on the internet.

Ertek, G., Aksu, B., Birbil, S. E., İkikat, M. C., Yıldırmaz, C (2005). “Application of local search methods for solving a quadratic assignment problem: A case study”, Proceedings of Computers and Industrial Engineering Conference, 2005

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ertek_et_al_cie2005

Dr. Gürdal Ertek recommends the following related books:

Operations Research

Optimization in Operations Research

 

 

 

In crossdocking, the inbound materials coming in trucks to the crossdock facility are directed to outbound doors and are directly loaded into trucks that will perform shipment, or are staged for a very brief time period before loading. Crossdocking has a great potential to bring savings in logistics: For example, most of the logistics success of Wal-Mart, the world’s leading retailer,  is attributed to crossdocking.In this paper,the types of crossdocking are identified, the situations and industries where crossdocking is applicable are explained, prerequisites, advantages and drawbacks are listed, and implementation issues are discussed. Finally a case study that describes the crossdocking applications of a 3rd party logistics firm is presented.

Ertek, G. (2005). “A tutorial on crossdocking”, Proceedings of 3rd International Logistics & Supply Chain Congress, Istanbul, Turkey.

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ertek_logistics2005

Dr. Gürdal Ertek recommends the following related books:

Facility Logistics

World-class Warehousing and Material Handling

 

 

 

Recent developments in information technology paved the way for the collection of large amounts of data pertaining to various aspects of an enterprise. The greatest challenge faced in processing these massive amounts of raw data gathered turns out to be the effective management of data with the ultimate purpose of deriving necessary and meaningful information out of it. The following paper presents an attempt to illustrate the combination of visual and analytical data mining techniques for planning of marketing and production activities. The primary phases of the proposed framework consist of filtering, clustering and comparison steps implemented using interactive pie charts, K-Means algorithm and parallel coordinate plots respectively. A prototype decision support system is developed and a sample analysis session is conducted to demonstrate the applicability of the framework.

Ertek, G., Kuruca, C., Aydin, C., Erel, B.F., Dogan, H., Duman, M., Ocal, M., and Ok, Z.D. (2004). “Visual and analytical mining of sales transaction data for production planning and marketing.” 4th International Symposium on Intelligent Manufacturing Systems, Sakarya, Turkey.

Note: This is the final draft version of this paper. Please cite this paper (or this final draft) as above.

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Visual and analytical mining of sales transaction data for production planning and marketing

Dr. Gürdal Ertek recommends the following related books:

Data Mining Techniques: For Marketing, Sales, and Customer Relationship Management Paperback – April 12, 2011

RapidMiner: Data Mining Use Cases and Business Analytics Applications (Chapman & Hall/CRC Data Mining and Knowledge Discovery Series) 1st Edition

Information Visualization: Design for Interaction (2nd Edition) 2nd Edition

 

 

 

 

 

 

 

We describe the application of simulation modeling to estimate and improve quality and productivity performance of a steel cord manufacturing system. We describe the typical steel cord manufacturing plant, emphasize its distinguishing characteristics, identify various production settings and discuss applicability of simulation as a management decision support tool. Besides presenting the general structure of the developed simulation model, we focus on wire fractures, which can be an important source of system disruption.

Turkseven, C.H., and Ertek, G. (2003). “Simulation modeling for quality and productivity in steel cord manufacturing,” in Chick, S., Sánchez, P., Ferrin,D., and Morrice, D.J. (eds.). Proceedings of 2003 Winter Simulation Conference. Institute of Electrical and Electronics Engineers (IEEE), Piscataway, New Jersey.

Note: This is the final draft version of this paper. Please cite this paper (or this final draft) as above.

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Simulation Modeling For Quality And Productivity In Steel Cord Manufacturing

Dr. Gürdal Ertek recommends the following related books:

Discrete-Event System Simulation (5th Edition) 5th Edition

Simulation Modeling and Analysis (McGraw-Hill Series in Industrial Engineering and Management) 5th Edition

 

 

 

We explore the impact of power structure on price, sensitivity of market price, and profits in a two-stage supply chain with single product, supplier and buyer, and a price sensitive market. We develop and analyze the case where the supplier has dominant bargaining power and the case where the buyer has dominant bargaining power. We consider a pricing scheme for the buyer that involves both a multiplier and a markup. We show that it is optimal for the buyer to set the markup to zero and use only a multiplier. We also show that the market price and its sensitivity are higher when operational costs (namely distribution and inventory) exist. We observe that the  sensitivity of the market price increases non-linearly as the wholesale price increases, and derive a lower bound for it. Through experimental analysis, we show that marginal impact of increasing shipment cost and carrying charge (interest rate) on prices and profits are decreasing in both cases. Finally, we show that there exist problem instances where the buyer may prefer supplier-driven case to markup-only buyer-driven and similarly problem instances where the supplier may prefer markup-only buyer-driven case to supplier-driven.

Ertek, G., and Griffin, P. (2002). “Supplier and buyer driven channels in a two-stage supply chain.” IIE Transactions, 34, 691-700.
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Supplier and Buyer Driven Channels in a Two-Stage Supply Chain

Dr. Gürdal Ertek recommends the following related books:

Game Theory: An Introduction Hardcover – January 6, 2013

Supply Chain Management, Volume 11: Design, Coordination and Operation (Handbooks in Operations Research and Management Science) 1st Edition

Designing and Managing the Supply Chain 3e with Student CD 3rd Edition

 

 

 

 

In this paper, we report development of interactive computer animations to demonstrate warehousing concepts, providing a virtual environment for learning. Almost every company, regardless of its industry, holds inventory of goods in its warehouse(s) to respond to customer demand promptly, to coordinate supply and demand, to realize economies of scale in manufacturing or processing, to add value to its products and to reduce response time. Design, analysis, and improvement of warehouse operations can yield significant savings for a company. Warehousing science can be considered as an important field within the industrial engineering discipline. However, there is very little educational material (including web based media), and only a handful of books available in this field. We believe that the animations that we developed will significantly contribute to the understanding of warehousing concepts, and enable tomorrow’s practitioners to grasp the fundamentals of managing warehouses.

Gurarslan, O., Guler, Y. H., Sahin, H., Ertek, G., Ozguven, K., Cacina, S. and Akkas, A. C. (2006). “Demonstrating warehousing concepts through interactive animations.” 5th International Symposium on Intelligent Manufacturing Systems, Sakarya, Turkey.

Note: This is the final draft version of this paper. Please cite this paper (or this final draft) as above.

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Demonstrating Warehousing Concepts Through Interactive Animations

Dr. Gürdal Ertek recommends the following related books:

Facility Logistics: Approaches and Solutions to Next Generation Challenges (Resource Management) 1st Edition

World-Class Warehousing and Material Handling 1st Edition