We developed a spreadsheet optimization model to find the optimal material handling policy at a leading yarn and tire cord manufacturer’s facility. The focus of the study is to optimize the movement of looms of yarn and tire cord between two major manufacturing steps. The considered flow network within the
manufacturing facility is a miniature two-stage supply chain, including the middle layer of depots. Movement of material takes place through forklift trucks and cranes, which impose electricity, labor, maintenance, and depreciation costs. After
introducing the company, the facility, and the project goals, we present the underlying linear programming (LP) model and our spreadsheet implementation. The results of our model suggest an annual saving of approximately $22,000 for the facility.
http://research.sabanciuniv.edu.
Optimizing Waste Collection In An Organized Industrial Region: A Case Studyertekg
Download Link > https://ertekprojects.com/gurdal-ertek-publications/blog/optimizing-waste-collection-in-an-organized-industrial-region-a-case-study/
In this paper we present a case study which involves the design of a supply chain network for industrial waste collection. The problem is to transport metal waste from 17 factories to containers and from containers to a disposal center (DC) at an organized region of automobile parts suppliers. We applied the classic mixed-integer programming (MIP) model for the two-stage supply chain to the solution of this problem. The visualization of the optimal solution provided us with several interesting insights that would not be easily discovered otherwise.
Optimizing waste collection in an organized industrial region: A case studyGurdal Ertek
In this paper we present a case study which involves the design of a supply chain network for industrial waste collection. The problem is to transport metal waste from 17 factories to containers and from containers to a disposal center (DC) at an
organized region of automobile parts suppliers. We applied the classic mixedinteger programming (MIP) model for the two-stage supply chain to the solution of this problem. The visualization of the optimal solution provided us with several
interesting insights that would not be easily discovered otherwise.
http://research.sabanciuniv.edu.
International Journal of Research in Engineering and Science is an open access peer-reviewed international forum for scientists involved in research to publish quality and refereed papers. Papers reporting original research or experimentally proved review work are welcome. Papers for publication are selected through peer review to ensure originality, relevance, and readability.
Crossdocking Insights from a Third Party Logistics Firm in TurkeyGurdal Ertek
Introduction:
In the book "The Silk Road: Two Thousand Years in the Heart of Asia," Wood (2002) remarkably suggests that "the very name of 'Silk Road' is somewhat misleading." Wood explains as follows: "It [the name 'Silk Road'] suggests a continuous journey, whereas goods were in fact transported by a series of routes, a series of agents, passing through many hands before they reached their ultimate destination."
http://research.sabanciuniv.edu.
Crossdocking Insights from a Third Party Logistics Firm in Turkeyertekg
Download Link > https://ertekprojects.com/gurdal-ertek-publications/blog/crossdocking-insights-from-a-third-party-logistics-firm-in-turkey/
In the book "The Silk Road: Two Thousand Years in the Heart of Asia," Wood (2002) remarkably suggests that "the very name of 'Silk Road' is somewhat misleading." Wood explains as follows: "It [the name 'Silk Road'] suggests a continuous journey, whereas goods were in fact transported by a series of routes, a series of agents, passing through many hands before they reached their ultimate destination."
It's striking to realize that the Silk Road was a complete "crossdocking" operation, executed on a geographically dispersed collection of hubs and routes. Products neither traveled on a single route, nor were they stored on the way. Rather, they were staged for short periods at the hubs, and then were passed on towards the next hub on the route, typically by a new caravan or transportation mode.
Today, crossdocking is still very important and popular. Crossdocking has a great potential to bring great financial and time savings in logistics. For example, most of the logistics success of Wal-Mart, the world’s leading retailer, is attributed to crossdocking.
...
Optimizing Waste Collection In An Organized Industrial Region: A Case Studyertekg
Download Link > https://ertekprojects.com/gurdal-ertek-publications/blog/optimizing-waste-collection-in-an-organized-industrial-region-a-case-study/
In this paper we present a case study which involves the design of a supply chain network for industrial waste collection. The problem is to transport metal waste from 17 factories to containers and from containers to a disposal center (DC) at an organized region of automobile parts suppliers. We applied the classic mixed-integer programming (MIP) model for the two-stage supply chain to the solution of this problem. The visualization of the optimal solution provided us with several interesting insights that would not be easily discovered otherwise.
Optimizing waste collection in an organized industrial region: A case studyGurdal Ertek
In this paper we present a case study which involves the design of a supply chain network for industrial waste collection. The problem is to transport metal waste from 17 factories to containers and from containers to a disposal center (DC) at an
organized region of automobile parts suppliers. We applied the classic mixedinteger programming (MIP) model for the two-stage supply chain to the solution of this problem. The visualization of the optimal solution provided us with several
interesting insights that would not be easily discovered otherwise.
http://research.sabanciuniv.edu.
International Journal of Research in Engineering and Science is an open access peer-reviewed international forum for scientists involved in research to publish quality and refereed papers. Papers reporting original research or experimentally proved review work are welcome. Papers for publication are selected through peer review to ensure originality, relevance, and readability.
Crossdocking Insights from a Third Party Logistics Firm in TurkeyGurdal Ertek
Introduction:
In the book "The Silk Road: Two Thousand Years in the Heart of Asia," Wood (2002) remarkably suggests that "the very name of 'Silk Road' is somewhat misleading." Wood explains as follows: "It [the name 'Silk Road'] suggests a continuous journey, whereas goods were in fact transported by a series of routes, a series of agents, passing through many hands before they reached their ultimate destination."
http://research.sabanciuniv.edu.
Crossdocking Insights from a Third Party Logistics Firm in Turkeyertekg
Download Link > https://ertekprojects.com/gurdal-ertek-publications/blog/crossdocking-insights-from-a-third-party-logistics-firm-in-turkey/
In the book "The Silk Road: Two Thousand Years in the Heart of Asia," Wood (2002) remarkably suggests that "the very name of 'Silk Road' is somewhat misleading." Wood explains as follows: "It [the name 'Silk Road'] suggests a continuous journey, whereas goods were in fact transported by a series of routes, a series of agents, passing through many hands before they reached their ultimate destination."
It's striking to realize that the Silk Road was a complete "crossdocking" operation, executed on a geographically dispersed collection of hubs and routes. Products neither traveled on a single route, nor were they stored on the way. Rather, they were staged for short periods at the hubs, and then were passed on towards the next hub on the route, typically by a new caravan or transportation mode.
Today, crossdocking is still very important and popular. Crossdocking has a great potential to bring great financial and time savings in logistics. For example, most of the logistics success of Wal-Mart, the world’s leading retailer, is attributed to crossdocking.
...
The team of ten members was tasked with designing a plant to manufacture and assemble hair dryers for use in regional peripheral warehouses, shopping malls, and shops. A well-equipped assembly area, a raw materials warehouse (RMW), a finished product warehouse (FPW), a semi-finished storage area, and service areas have all been available at the plant. Geometric and volumetric sizing, lines and/or cells and/or work departments, shelving, reception areas, shipping areas, picking areas, packaging areas, and finished product containment buildings were all the responsibility of each project team.
Application of local search methods for solving a quadratic assignment proble...Gurdal Ertek
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.
http://research.sabanciuniv.edu.
Optimization of Design Parameters for Crane Hook Using Finite Element AnalysisIJRTEMJOURNAL
The Crane hooks are very at risk segments that are regularly utilized for mechanical purposes.
In this way such segments in an industry must be produced and composed in an approach to convey most extreme
execution without failure. Failure of a crane hook essentially relies upon three central point i.e. measurement,
material, overload. The undertaking is worried towards expanding the safe load by fluctuating the cross-sectional
measurements of the four distinct segments and diverse materials. The chose areas are square, circle, and
trapezoidal. The territory stays consistent while changing the measurements of the four unique segments. The
crane hook is demonstrated utilizing catia programming. The pressure and life investigation is finished utilizing
ANSYS 18.1 workbench. The ordinary worry along add up to misshaping, stress and life’s according to the
materials considered. It is discovered that trapezoidal cross segment yields most extreme load of 4000 KG to 5000
KG for steady cross segment zone among four cross segment.
A New Network Flow Model for Determining the Assortment of Roll Types in Pack...Gurdal Ertek
This paper reports work motivated by a real world assortment problem in packaging industry. A novel network flow model has been developed to solve the problem of selecting the optimal set of roll types for use in production. The model can incorporate fixed costs that depend on the number of elements in the assortment as well as the selected roll types. While the trade-off between inventory cost and cost of waste is resolved optimally through the model, graphical understanding of the trade-off can bring insights into the decision making process.
This graphical analysis has been demonstrated on a computational example.
http://research.sabanciuniv.edu.
Design and Implementation of Multiplier Using Kcm and Vedic Mathematics by Us...IJMER
International Journal of Modern Engineering Research (IJMER) is Peer reviewed, online Journal. It serves as an international archival forum of scholarly research related to engineering and science education.
Application Of Local Search Methods For Solving A Quadratic Assignment Probl...ertekg
Download Link > https://ertekprojects.com/gurdal-ertek-publications/blog/application-of-local-search-methods-for-solving-a-quadratic-assignment-problem-a-case-study/
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.
A Minimum Spanning Tree Approach of Solving a Transportation Probleminventionjournals
: This work centered on the transportation problem in the shipment of cable troughs for an underground cable installation from three supply ends to four locations at a construction site where they are needed; in which case, we sought to minimize the cost of shipment. The problem was modeled into a bipartite network representation and solved using the Kruskal method of minimum spanning tree; after which the solution was confirmed with TORA Optimization software version 2.00. The result showed that the cost obtained in shipping the cable troughs under the application of the method, which was AED 2,022,000 (in the United Arab Emirate Dollar), was more effective than that obtained from mere heuristics when compared
Supplier and buyer driven channels in a two-stage supply chainGurdal Ertek
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.
http://research.sabanciuniv.edu.
Simulation modeling for quality and productivity in steel cord manufacturingGurdal Ertek
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.
http://research.sabanciuniv.edu.
More Related Content
Similar to Spreadsheet Optimization of Flow for WIP Goods at a Yarn and Tire Cord Manufacturer: A Case Study
The team of ten members was tasked with designing a plant to manufacture and assemble hair dryers for use in regional peripheral warehouses, shopping malls, and shops. A well-equipped assembly area, a raw materials warehouse (RMW), a finished product warehouse (FPW), a semi-finished storage area, and service areas have all been available at the plant. Geometric and volumetric sizing, lines and/or cells and/or work departments, shelving, reception areas, shipping areas, picking areas, packaging areas, and finished product containment buildings were all the responsibility of each project team.
Application of local search methods for solving a quadratic assignment proble...Gurdal Ertek
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.
http://research.sabanciuniv.edu.
Optimization of Design Parameters for Crane Hook Using Finite Element AnalysisIJRTEMJOURNAL
The Crane hooks are very at risk segments that are regularly utilized for mechanical purposes.
In this way such segments in an industry must be produced and composed in an approach to convey most extreme
execution without failure. Failure of a crane hook essentially relies upon three central point i.e. measurement,
material, overload. The undertaking is worried towards expanding the safe load by fluctuating the cross-sectional
measurements of the four distinct segments and diverse materials. The chose areas are square, circle, and
trapezoidal. The territory stays consistent while changing the measurements of the four unique segments. The
crane hook is demonstrated utilizing catia programming. The pressure and life investigation is finished utilizing
ANSYS 18.1 workbench. The ordinary worry along add up to misshaping, stress and life’s according to the
materials considered. It is discovered that trapezoidal cross segment yields most extreme load of 4000 KG to 5000
KG for steady cross segment zone among four cross segment.
A New Network Flow Model for Determining the Assortment of Roll Types in Pack...Gurdal Ertek
This paper reports work motivated by a real world assortment problem in packaging industry. A novel network flow model has been developed to solve the problem of selecting the optimal set of roll types for use in production. The model can incorporate fixed costs that depend on the number of elements in the assortment as well as the selected roll types. While the trade-off between inventory cost and cost of waste is resolved optimally through the model, graphical understanding of the trade-off can bring insights into the decision making process.
This graphical analysis has been demonstrated on a computational example.
http://research.sabanciuniv.edu.
Design and Implementation of Multiplier Using Kcm and Vedic Mathematics by Us...IJMER
International Journal of Modern Engineering Research (IJMER) is Peer reviewed, online Journal. It serves as an international archival forum of scholarly research related to engineering and science education.
Application Of Local Search Methods For Solving A Quadratic Assignment Probl...ertekg
Download Link > https://ertekprojects.com/gurdal-ertek-publications/blog/application-of-local-search-methods-for-solving-a-quadratic-assignment-problem-a-case-study/
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.
A Minimum Spanning Tree Approach of Solving a Transportation Probleminventionjournals
: This work centered on the transportation problem in the shipment of cable troughs for an underground cable installation from three supply ends to four locations at a construction site where they are needed; in which case, we sought to minimize the cost of shipment. The problem was modeled into a bipartite network representation and solved using the Kruskal method of minimum spanning tree; after which the solution was confirmed with TORA Optimization software version 2.00. The result showed that the cost obtained in shipping the cable troughs under the application of the method, which was AED 2,022,000 (in the United Arab Emirate Dollar), was more effective than that obtained from mere heuristics when compared
Supplier and buyer driven channels in a two-stage supply chainGurdal Ertek
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.
http://research.sabanciuniv.edu.
Simulation modeling for quality and productivity in steel cord manufacturingGurdal Ertek
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.
http://research.sabanciuniv.edu.
Visual and analytical mining of sales transaction data for production plannin...Gurdal Ertek
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.
http://research.sabanciuniv.edu.
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.
http://research.sabanciuniv.edu.
Financial benchmarking of transportation companies in the New York Stock Exch...Gurdal Ertek
In this paper, we present a benchmarking study of industrial transportation companies traded in the New York Stock Exchange (NYSE). There are two distinguishing aspects of our study: First, instead of using operational data for the input and the output items of the developed Data Envelopment Analysis (DEA) model, we use financial data of the companies that are readily available on the Internet. Secondly, we visualize the efficiency scores of the companies in relation to the subsectors and the number of employees. These visualizations enable us to discover interesting insights about the companies within each subsector, and about subsectors in comparison to each other. The visualization approach that we employ can be used in any DEA study that contains subgroups within a group. Thus, our paper also contains a methodological contribution.
http://research.sabanciuniv.edu.
Development of an Interactive Simulation of Steel Cord Manufacturing for Indu...Gurdal Ertek
We developed an interactive simulation program to be used in industrial engineering education, based on an earlier simulation study of a steel cord manufacturing plant. In the class project, the students are asked to design strategies/algorithms for finding the optimal values of operational decision variables by using the program.
http://research.sabanciuniv.edu.
Application of the analytic hierarchy process (AHP) for selection of forecast...Gurdal Ertek
In this paper, we described an application of the Analytic Hierarchy Process (AHP) for the ranking and selection of forecasting software. AHP is a multi-criteria decision making (MCDM) approach, which is based on the pair-wise comparison
of elements of a given set with respect to multiple criteria. Even though there are applications of the AHP to software selection problems, we have not encountered a study that involves forecasting software. We started our analysis by filtering
among forecasting software that were found on the Internet by undergraduate students as a part of a course project. Then we processed a second filtering step, where we reduced the number of software to be examined even further. Finally we
constructed the comparison matrices based upon the evaluations of three “semiexperts”, and obtained a ranking of forecasting software of the selected software using the Expert Choice software. We report our findings and our insights, together with the results of a sensitivity analysis.
http://research.sabanciuniv.edu.
Demonstrating warehousing concepts through interactive animationsGurdal Ertek
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.
http://research.sabanciuniv.edu.
Decision Support For Packing In WarehousesGurdal Ertek
Packing problems deal with loading of a set of items (ob-
jects) into a set of boxes (containers) in order to optimize a performance criterion under various constraints. With the advance of RFID technologies and investments in IT infrastructures companies now have Access to the necessary data that can be utilized in cost reduction of packing processes. Therefore bin packing and container loading problems are be-
coming more popular in recent years. In this research we propose a beam search algorithm to solve a packing problem that we encountered in a real world project. The 3D-MBSBPP (Multiple Bin Sized Bin Packing Problem) that we present and solve has not been analyzed in literatüre before, to the best of our knowledge. We present the performance of our proposed beam search algorithm in terms of both cost and computational
time in comparison to a greedy algorithm and a tree search enumeration algorithm.
http://research.sabanciuniv.edu.
A framework for visualizing association mining resultsGurdal Ertek
Association mining is one of the most used data mining tech-
niques due to interpretable and actionable results. In this study we propose a framework to visualize the association mining results, specifically frequent itemsets and association rules, as graphs. We demonstrate the applicability and usefulness of our approach through a Market Basket Analysis (MBA) case study where we visually explore the data mining results for a supermarket data set. In this case study we derive several
interesting insights regarding the relationships among the items and suggest how they can be used as basis for decision making in retailing.
http://research.sabanciuniv.edu.
Application of the cutting stock problem to a construction company: A case studyGurdal Ertek
This paper presents an application of the well-known cutting stock problem to a construction firm. The goal of the 1Dimensional (1D) cutting stock problem is to cut the bars of desired lengths in required quantities from longer bars of given
length. The company for which we carried out this study encounters 1D cutting stock problem in cutting steel bars (reinforcement bars) for its construction projects. We have developed several solution approaches to solving the company’s problem: Building and solving an integer programming (IP) model in a modeling environment, developing our own software that uses a mixed integer programming (MIP) software library, and testing some of the commercial software packages available on the internet. In this paper, we summarize our experiences with all the three approaches. We also present a benchmark of existing commercial software packages, and some critical insights. Finally, we suggest a visual approach for increasing performance in solving the cutting stock problem and demonstrate the applicability of this approach using the company’s data on two construction projects.
http://research.sabanciuniv.edu.
Benchmarking the Turkish apparel retail industry through data envelopment ana...Gurdal Ertek
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the industry and revealing guidelines that can aid in strategic decision making.
http://research.sabanciuniv.edu.
Impact of Cross Aisles in a Rectangular Warehouse:A Computational StudyGurdal Ertek
Order picking is typically the most costly operation in a warehouse and traveling is typically the most time consuming task within order picking. In this study we focus on the layout design for a rectangular warehouse, a warehouse with parallel storage blocks with main aisles separating them. We specifically analyze the impact of adding cross aisles that cut storage blocks perpendicularly, which can reduce travel times during order picking by introducing flexibility in going from one main aisle to the next. We consider two types of cross aisles, those that are equally spaced (Case 1) and those that are unequally spaced, which respectively have equal and unequal distances among them. For Case 2, we extend an earlier model and present a heuristic algorithm for finding the best distances among cross aisles. We carry out extensive computational experiments for a variety of warehouse designs. Our findings suggest that warehouse planners can obtain great travel time savings through establishing equally spaced cross aisles, but little additional savings in unequally-spaced cross isles. We present a look-up table that provides the best number of equally spaced cross aisles when the number of cross aisles
(N) and the length of the warehouse (T) are given. Finally, when the values of N and T are not known, we suggest establishing three cross aisles in a warehouse.
http://research.sabanciuniv.edu.
Visual mining of science citation data for benchmarking scientific and techno...Gurdal Ertek
In this paper we present a study where we visually analyzed science citation data to investigate the competitiveness of world countries in selected categories of science. The dataset that we worked on in our study includes the number of papers published
and the number of citations made in the ESI (Essential Science Indicators) database in 2004. The dataset lists these values for practically every country in the world. In analyzing the data, we employ methods and software tools developed and used in the data mining and information visualization fields of the Computer Science. Some of the questions for which we look for answers in this study are the following: (a) Which countries are most competitive in the selected categories of science? (i.e.
Engineering, Computer Science, Economics & Business) (b) What type of correlations exist between different categories of science? For example, do countries with many published papers in the field of Engineering science also have many papers published on Computer Science or Economics & Business? (c) Which countries produce the most influential papers? This analysis is needed since a country may have
many papers published but these papers may be cited very rarely. (d) Can we gain useful and actionable insights by combining science citation data with socioeconomic and geographical data?
http://research.sabanciuniv.edu.
An open source Java code for visualizing supply chain problemsGurdal Ertek
In this paper, we decribe an open source Java class library for visualizing supply chain problems within a geographical context. The highly competitive markets and recent technological advances make the use of such supply chain
network visualizations critical in both strategic and tactical levels. The most important characteristic of our work is its easy integration with any Java application. Our software differs from any other commercial and open source supply chain visualization tool by its simple structure, easy adoption and
implementation and high compatibility. The main motivation of our study was to develop a simple – yet effective – library that would not require to learn and apply complicated visualization tools and data structures such as Geographical Information Systems (GIS). In this study, we illustrate the use of our visualization tool through maps of Turkey, Europe, North and South America, the United States and the NAFTA. We believe that ease of visualization offered by our open source tool will contribute to a multitude of projects in supply chain design, as well as increasing productive communication among practitioners, especially involved in strategic level decision making processes. We foresee that our supply chain visualization tool will fill a gap in this area with its simple but effective structure.
http://research.sabanciuniv.edu.
Opendatabay - Open Data Marketplace.pptxOpendatabay
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Empowering the Data Analytics Ecosystem: A Laser Focus on Value
The data analytics ecosystem thrives when every component functions at its peak, unlocking the true potential of data. Here's a laser focus on key areas for an empowered ecosystem:
1. Democratize Access, Not Data:
Granular Access Controls: Provide users with self-service tools tailored to their specific needs, preventing data overload and misuse.
Data Catalogs: Implement robust data catalogs for easy discovery and understanding of available data sources.
2. Foster Collaboration with Clear Roles:
Data Mesh Architecture: Break down data silos by creating a distributed data ownership model with clear ownership and responsibilities.
Collaborative Workspaces: Utilize interactive platforms where data scientists, analysts, and domain experts can work seamlessly together.
3. Leverage Advanced Analytics Strategically:
AI-powered Automation: Automate repetitive tasks like data cleaning and feature engineering, freeing up data talent for higher-level analysis.
Right-Tool Selection: Strategically choose the most effective advanced analytics techniques (e.g., AI, ML) based on specific business problems.
4. Prioritize Data Quality with Automation:
Automated Data Validation: Implement automated data quality checks to identify and rectify errors at the source, minimizing downstream issues.
Data Lineage Tracking: Track the flow of data throughout the ecosystem, ensuring transparency and facilitating root cause analysis for errors.
5. Cultivate a Data-Driven Mindset:
Metrics-Driven Performance Management: Align KPIs and performance metrics with data-driven insights to ensure actionable decision making.
Data Storytelling Workshops: Equip stakeholders with the skills to translate complex data findings into compelling narratives that drive action.
Benefits of a Precise Ecosystem:
Sharpened Focus: Precise access and clear roles ensure everyone works with the most relevant data, maximizing efficiency.
Actionable Insights: Strategic analytics and automated quality checks lead to more reliable and actionable data insights.
Continuous Improvement: Data-driven performance management fosters a culture of learning and continuous improvement.
Sustainable Growth: Empowered by data, organizations can make informed decisions to drive sustainable growth and innovation.
By focusing on these precise actions, organizations can create an empowered data analytics ecosystem that delivers real value by driving data-driven decisions and maximizing the return on their data investment.
Data Centers - Striving Within A Narrow Range - Research Report - MCG - May 2...pchutichetpong
M Capital Group (“MCG”) expects to see demand and the changing evolution of supply, facilitated through institutional investment rotation out of offices and into work from home (“WFH”), while the ever-expanding need for data storage as global internet usage expands, with experts predicting 5.3 billion users by 2023. These market factors will be underpinned by technological changes, such as progressing cloud services and edge sites, allowing the industry to see strong expected annual growth of 13% over the next 4 years.
Whilst competitive headwinds remain, represented through the recent second bankruptcy filing of Sungard, which blames “COVID-19 and other macroeconomic trends including delayed customer spending decisions, insourcing and reductions in IT spending, energy inflation and reduction in demand for certain services”, the industry has seen key adjustments, where MCG believes that engineering cost management and technological innovation will be paramount to success.
MCG reports that the more favorable market conditions expected over the next few years, helped by the winding down of pandemic restrictions and a hybrid working environment will be driving market momentum forward. The continuous injection of capital by alternative investment firms, as well as the growing infrastructural investment from cloud service providers and social media companies, whose revenues are expected to grow over 3.6x larger by value in 2026, will likely help propel center provision and innovation. These factors paint a promising picture for the industry players that offset rising input costs and adapt to new technologies.
According to M Capital Group: “Specifically, the long-term cost-saving opportunities available from the rise of remote managing will likely aid value growth for the industry. Through margin optimization and further availability of capital for reinvestment, strong players will maintain their competitive foothold, while weaker players exit the market to balance supply and demand.”
Spreadsheet Optimization of Flow for WIP Goods at a Yarn and Tire Cord Manufacturer: A Case Study
1. 1 / 16
Mataraci, B. and Ertek, G. (2006). "Spreadsheet optimization of flow for WIP goods at a yarn
and tire cord manfacturer: A case study.” 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. You can download this final draft from http://research.sabanciuniv.edu.
Spreadsheet Optimization of Flow for WIP Goods
at a Yarn and Tire Cord Manufacturer: A Case Study
Berat Mataraci, Gurdal Ertek
Sabanci University, Faculty of Engineering and Natural Sciences,
Orhanli, Tuzla, 34956, Istanbul, Turkey
2. 2 / 16
Abstract
We developed a spreadsheet optimization model to find the optimal material
handling policy at a leading yarn and tire cord manufacturer’s facility. The focus of
the study is to optimize the movement of looms of yarn and tire cord between two
major manufacturing steps. The considered flow network within the
manufacturing facility is a miniature two-stage supply chain, including the middle
layer of depots. Movement of material takes place through forklift trucks and
cranes, which impose electricity, labor, maintenance, and depreciation costs. After
introducing the company, the facility, and the project goals, we present the
underlying linear programming (LP) model and our spreadsheet implementation.
The results of our model suggest an annual saving of approximately $22,000 for
the facility.
Submission areas: Manufacturing Systems Engineering, Decision Support Systems
Introduction
Material handling is a significant activity that takes place at every manufacturing facility where
final product(s) are produced. Significant amount of labor, equipment, and energy (electricity)
costs may be incurred for material handling, especially when the materials handled are bulky.
The composition of the material handling costs at a facility depends on the product
characteristics, and the selection of labor and equipment alternatives.
This paper reports an industrial engineering project carried out to reduce material handling
costs at a yarn and tire cord manufacturing facility in Turkey. The equipment used in the facility
include forklift trucks and cranes. The technique used to improve the system is linear
programming (LP), a fundamental deterministic modeling and optimization technique in
operations research, used frequently by industrial engineers. After identifying the material
3. 3 / 16
handling problem at the manufacturing facility, the facility structure is analyzed and the cost
parameters related with operating the equipment are calculated. Then a spreadsheet model is
built using MS Excel software and is solved to optimality using Excel’s Solver. Operations
research can have a remarkable impact on improving operational profitability in almost any
company, in almost every function. In this project, the operating strategy suggested brought an
improvement of approximately $22,000 annually.
The Company and the Manufacturing Facility
Our project was primarily concerned with the long-run profit maximization of material handling
activities within Izmit, Turkey manufacturing facility of Kordsa1 (Sabanci Dupont Industrial
Yarn and Tire Cord Fabric Manufacturing and Trading Inc.) There are approximately 800
people working at the Izmit facility and there are approximately 20 people working at Kordsa
Head Office at Sabanci Center in Istanbul, Turkey. The Izmit facility is located within KENTSA
(SA City), a large manufacturing complex operated by the Sabanci Group which focuses on tire
manufacturing.
Kordsa, founded in 1972 as a manufacturer of yarn and tire cord, now operates in seven
countries, with 9 manufacturing facilities. Kordsa International, the majority shareholder of
Kordsa is owned by Sabanci Holding with headquarters in Wilmington Delaware, USA. Some of
the companies where Kordsa Int. has shares are Nilekords (Egypt, with %51 share of Kordsa
Int.), Interkordsa (Germany, with %80 share of Kordsa Int.), Kiankordsa (Iran, with %60 share
of Kordsa Int.), Kordsa Argentina and Kordsa Brasil (under 100% ownership of Kordsa Int.)
Kordsa has a remarkable market share in Turkey and in Europe with respect to tire cord
products. The company also offers a wide range of products to textile industry. Figure 1
illustrates the Nylon 6.6 yarn manufactured by Kordsa, which comprises approximately %75 of
total production at the Izmit plant.
1
http://www.kordsa.com.tr
4. 4 / 16
Figure 1. Nylon 6.6 produced at Kordsa; Source: http://www.kordsa.com.tr
There are 3 factories located in Kordsa’s Izmit facility: Kordsa 1, 2, and 3. Kordsa 1 was founded
in 1973 and now produces only yarn fabric. In 1980’s Kordsa 2 started its operations to produce
industrial fabrics such as liner and chafer. Finally, Kordsa 3 was founded in 1993 as a part of the
growth strategy of expanding into global markets and integrating into yarn and cord fabric.
Kordsa 1 survived and succeeded in the long-term due to developing competitive strategies in its
industry. After assessing the condition of the market, the managers of Kordsa made the strategic
decision of having a dominant role in industrial fabrics as a part of their growth strategy. As a
result, Kordsa 2 was built to fill the gap in the sector. Finally, Kordsa 3 was built to expand a
company’s capacity.
Figure 2 illustrates the manufacturing steps at Kordsa. First, twisting is carried out to increase
the strength of the yarn. Then, the twisted yarn is woven together on looms at dedicated Kordsa
1, 2 and 3 factories. Finally, dipping and hot-stretching are carried out as fundamental steps in
tire cord fabric manufacturing.
5. 5 / 16
The Project
The scope of our project was the flow of material between Kordsa 1 and 3 factories and the
dipping facilities. The output of the factories is looms of yarn, which are transported to one of
the three depots (Depots 1, 2, and 3) to be stored for some time, and then transported to one of
the two dipping facilities (Dipping Facilities 1 and 2).
Figure 3 gives an illustration of the system considered. The illustration suggests that the system
considered is a network of nodes and arcs, where flow takes place on arcs to move work-in-
process looms between nodes (factories, depots, and dipping facilities). The figure is illustrative
and does not reflect the real distances (due to confidentiality). In reality distances play a crucial
role in the costs of using each of the arcs in the network. For example, there is considerable
distance between Kordsa 1 and Kordsa 3, which has implications for arc costs. Kordsa 2 factory
is not considered in the project since the flow out of that factory is already determined. Instead,
products coming from contractors are considered in the project by representing contractors as a
factory.
The goal of the project was to decide on how the flow should be distributed to the arcs in the
network. The flows of the work-in-process (WIP) looms are currently distributed to arcs in an
ad-hoc manner. The goal is to minimize the total cost of transportation on all arcs.
Transportation is carried out with forklifts (Figure 4a) and cranes (Figures 4b and 4c shown
empty crane and crane loaded with a loom). These equipment impose a great deal of costs,
especially when the associated depreciation, maintenance and labor costs in operating the
forklift trucks are taken into consideration.
The distances in the network are accurately calculated by using the CAD drawings provided by
the Kordsa management. Afterwards, costs of the equipment are calculated in terms of data
given such as cost of energy (electricity) spent for crane and forklifts (in kW per hour).
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Figure 3. The network to be optimized
(a) (b) (c)
Figure 4. Pictures for forklift (a) and empty (b) and full crane (c)
8. 8 / 16
The Mathematical Model
The problem that we considered is essentially a network flow optimization problem considering
the network in Figure 3.
The mathematical model is presented below:
SETS:
I : set of factories, i=1,2,3 to represent Contract Manufacturing, Kordsa 1 and Kordsa 3 factories
(Kordsa 2 is excluded since it is not considered in this project)
J : set of depots ( inventory locations), j=1,2,3.
K :set of dipping facilities, k=1,2.
DECISION VARIABLES:
ijx : flow of factory i to depot j.
jky : flow from depot j to dipping facility k.
t : number of inventory turns
ju : total flow that passes through depot j.
9. 9 / 16
PARAMETERS:
ijc : cost of flow from factory i to depot j
jkd : cost flow of one roll from depot j to dipping facility k
jM : maximum storage capacity of depot j
iF : flow out of factory i
kD : demand at dipping facility k
THE MODEL
Min
KJkj
jkjk
JIji
ijij ydxc
),(),(
(1)
s.t IiFx
Jj
iij
, (2) Flow out of supply nodes
(factories)
Jj
kjk KkDy , (3) Flow into demand nodes
(dipping facilities)
Ii
ijj Jjxu ,
Kk
jkj Jjyu ,
(4) Flow balance constraints
(depots)
10. 10 / 16
JjtMu jj ,
(5) Inventory turnover
constraints
(depots)
0,,, tuyx jjkij
(6) Non-negativity constraints
The objective of the LP model is to minimize the total cost of transporting the WIP goods from
the factories to the depots, and then from the depots to the dipping facilities (1). The flows out of
the factories and into the dipping facilities are given as parameters and should be satisifed
(2),(3). The inflow and outflow at the depots should be equal (4). The inventory turns at the
depots are not known. However, the capacities of each depot are known. Therefore we assume
that the inventory turnovers at each of the depots are equal, and we thus include the necessary
constraints in the mathematical model and the spreadsheet model (5).
The Spreadsheet Model
The Model
The spreadsheet implementation of the presented mathematical model is shown in Figures 5
and 6. In Figure 5, the real values are replaced by the parameter/variable symbols due to
confidentiality. The cells linked with lines have to be equal to each other. Before running the
Solver to solve the model, the options “Assume Linear Model” and “Assume Non-negative” are
selected.
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Figure 5. The spreadsheet optimization model: The view of the model worksheet.
Figure 6. The spreadsheet optimization model: Solver parameters.
12. 12 / 16
Spreadsheet Modeling Guidelines
Conway and Rugsdale provide some guidelines for good design of spreadsheet models, including
the following:
Numeric constants (the parameters in our case) should not be placed directly into
formulas, but should be put into separate cells, so that they can be modified easily.
The data should be organized and then arranged in the spreadsheet with a reasonable
layout.
Logically related elements should be arranged into cell groups that have close proximity.
Column and row totals should be placed in cells close to the column and rows that they
are summing up.
Shading and borders should be used to distinguish parameters (which can be changed by
the user to create new scenarios) from variables (which will be changed by the solver during the
optimization process).
Text boxes and cell notes should be used to document the model.
All these guidelines were followed in our spreadsheet model.
Advantages of Using Spreadsheet Modeling
The advantages of using a spreadsheet model -rather than using an IDE (Integrated
Development Environment) for LP (such as AMPL2, GAMS3 or LINDO4)- are the following:
2
http://www.ampl.com
3
http://www.gams.com
4
http://www.lindo.com
13. 13 / 16
Spreadsheets are used by people at all levels of an enterprise, from the foreman to the
CEO. Almost everyone knows how to read and use –at least at a basic level- spreadsheet
software. This enables accessibility of the model to decision makers at the company. The model
that we developed was easily communicated to middle-level managers and foremen at the
project’s presentation, drawing their interest and encouraging their participation.
The spreadsheet model requires no apriori knowledge of or experience with LP at all.
Anyone can “hack” the model and rerun the Solver to see the results of new scenarios. If an LP
IDE were used, it would be very difficult for the people at Kordsa to use it.
The coloring of the cells, and other formatting alternatives in the spreadsheet software
makes the model even more understandable and usable.
The MS Excel spreadsheet software is present at almost every company, whereas an LP
IDE would require a special purchase and thus additional cost.
One special issue related with our model is that it is extremely simple and easy, even though it
suggests significant savings. The authors had experienced earlier that MS Excel Solver may run
into computational problems when attempting to solve large nonlinear problems. However, the
solution of a small LP problem through MS Excel Solver is typically found with great accuracy in
almost no time.
The Savings
When the spreadsheet model is solved the optimal energy (electricity) cost of transportation is
found to be $1,747. However, the existing system requires much more than this cost. Under
existing circumstances, the energy costs for transportation amount to $2,109 per month. The
difference between these two cost figures show that the model suggests a monthly saving of
$362 with respect to electricity. This translates in $4,343 annually. There are also labor savings
14. 14 / 16
due to eliminating a truck operator and due to maintenance and depreciation costs of the lift
trucks. The total annual saving proposed by our spreadsheet model is approximately $22,000.
Related Work
Caine and Parker (1996) report a decade ago that spreadsheet software had enabled LP to
become a viable option for solving managerial problems and performing sensitivity analysis of
results. They illustrate how a simple LP problem can be modeled using Excel’s Solver.
Two of the spreadsheet optimization applications reported in literature are the following:
Cunha and Mutarelli (forthcoming) have implemented a spreadsheet model to optimize
the production and distribution decisions for a Brazilian newsmagazine. Their model is based on
a mixed-integer programming (MIP) formulation. Since their problem is fairly large, the authors
report using the spreadsheet optimizer What’s Best!5. They report that they have saved 7.1% in
costs, totaling to over $600,000 annually.
Buehlmann et al. (2000) describe a decision support system that they have developed to
optimize production of wood panels. Their implementation in MS Excel derives data from
several worksheets, and provides a user-friendly interface for changing the parameters of the
problem and thus solving new instances of the problem.
Other applications that can be found in literature focus on optimally allocating resources to
research and development projects (Sonntag and Grossman, 1999), optimally assigning
managers to construction projects (LeBlanc et al. 2000), and determining the optimal
maintenance schedules for marine machinery (Artana and Ishida, 2002).
5
http://www.lindo.com
15. 15 / 16
Conclusions
Material handling is is an integral part of a manufacturing system. Modeling and analysis of
material handling with the aid of spreadsheet software can offer great opportunities for reducing
costs, as we have shown in this paper.
In our project, the aggregate flow was optimized through a tactical model, rather than
determining the exact flow amounts of individual products. The operational decision of how to
dynamically allocate flow of products is still left to the foremen at the facility. Our model simply
gives the percentages of aggregate flows that should take place on the average, which serve as
guidelines.
Due to unpredictable customer’s demands, the solution suggested by this project was not yet
implemented at Kordsa, at the time this paper was being writtten. However, it has definitely
provided the Kordsa managers with insights on how to manage the material flow throughout the
plant, and how to use spreadsheets to bring operational savings.
Acknowledgement
We would like to thank Nuri Duzgoren and Gurkan Gezen at Kordsa for their continuous
support of my project. We would also like to also thank Mustafa Beyaziler, Eren Maden, and
Kivanc Kolukisa for providing the equipment illustrations that they created using AC3D and
SolidWorks software. Finally, we would like to thank Guler Kizilenis and Ayhan Aydin at
Sabanci University for reviewing our paper and suggesting improvements.
16. 16 / 16
References
Artana, K. B. and Ishida, K. (2002) Spreadsheet modeling of optimal maintenance schedule for
components in wear-out phase. Reliability Engineering & System Safety, vol: 77, 81-91.
Buehlmann, U., Ragsdale, C. T. and Gfeller, B. (2000) A spreadsheet-based decision support
system for wood panel manufacturing. Decision Support Systems, vol: 29, 207-227.
Caine, D. J. and Parker, B. J. (1996) Linear programming comes of age: a decision-support tool
for every manager. Management Decision, vol: 34 no: 4, 46–53.
Conway, D. G. and Ragsdale, C. T. (1997) Modeling Optimization Problems in the Unstructured
World of Spreadsheets. Omega, vol: 25, no: 3, 313-322.
Cunha, C. B. and Mutarelli, F. (forthcoming) A spreadsheet-based optimization model for the
integrated problem of producing and distributing a major weekly newsmagazine. European
Journal of Operational Research.
LeBlanc, L. J., Randels, D. and Swan, T. K. (2000) Heery International’s spreadsheet
optimization model for assigning managers to construction projects. Interfaces, vol: 30, no: 6,
95-106.
Sonntag, C. and Grossman, T. A. (1999) End-user modeling improves R&D management at
AgrEvo Canada, Inc. Interfaces, vol: 29, no: 5, 132-142.