Download Link > https://ertekprojects.com/gurdal-ertek-publications/blog/simulation-modeling-for-quality-and-productivity-in-steel-cord-manufacturing/
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.
This document provides instructions for making ice rings using Swarovski Crystallized beads and elements. The 10 step process involves: 1) Forming loops on beads and attaching them to headpins; 2) Connecting beads together by stringing them on wire and wrapping the ends; 3) Adding a crystal stone to the wrapped bead circle; 4) Creating a spiral wire ring and attaching it to the bead assembly; 5) Opening and wrapping the spiral ring loops; 6) Trimming and hiding the wire ends. Tools include headpins, wire, pliers, mandrels and cutters.
This document discusses soldering and cleaning processes for high-performance printed circuit boards. It covers topics like solder alloy composition, flux usage, solder paste characteristics, and post-assembly cleaning requirements. It also addresses environmentally-friendly circuit board materials and processes, including pollution prevention strategies like reducing water usage and implementing recycling programs.
Palestra 4 - Avanços em tecnologia de fresamento: do fresamento convencional ...senaimais
Advances in milling Technologies: from convencional milling to HSC.
Palestrante: Msc. Benedikt Gellissen - Instituto Fraunhofer de Tecnologias da Produção - FhG IPT - Alemanha
SSMA connectors are precision connectors that perform up to 40GHz. They are commonly used where smaller size and higher density are needed. Cmpter offers SSMA receptacles, adapters, and connectors for semi-rigid and flexible cable that can be customized for applications. SSMA connectors have excellent performance up to 40GHz, low VSWR and insertion loss, and rugged construction for reliability.
Alpha exactalloy Solder preforms for product and process improvementreginahuse
There is an Exactalloy™ preform in the rightshape and size to improve your assembly operation, product reliability and quality. Get Technical support from Krayden Regarding Alpha product and its proper application method.
Bodycote is a publicly traded company with over $1 billion in annual sales and over 10,000 employees across 200 locations in 36 countries. Their Silao, Mexico facility opened in 2007 and provides various heat treating services for automotive and industrial applications, including carburizing, carbonitriding, ferritic nitrocarburizing, and shot peening. The facility has atmospheric furnaces, low pressure carburizing systems, batch furnaces, and metallurgical testing capabilities. Bodycote invites customers to provide part details to obtain quotes for heat treating and surface enhancement services.
Hybrid processes combine multiple manufacturing technologies to overcome limitations of conventional machining. This presentation defines hybrid processes as combining active principles that significantly influence the machining process. It provides examples of hybrid technologies like vibration-assisted machining, laser-assisted machining, and combinations of EDM/ECM with other processes. The goal of hybrid processes is to enable machining of difficult materials more efficiently.
The document discusses high performance printed circuit boards. It defines key terms like laminates, glass transition temperature, and loss tangent. It describes various laminate materials like FR-4, bismaleimide triazine epoxy, polyimide, and PTFE, comparing their properties and costs. It also discusses microvias, multilayer circuit boards, and different processes for forming microvias. Finally, it covers substrates for RF and microwave systems, describing transmission lines and via structures used in high frequency applications.
This document provides instructions for making ice rings using Swarovski Crystallized beads and elements. The 10 step process involves: 1) Forming loops on beads and attaching them to headpins; 2) Connecting beads together by stringing them on wire and wrapping the ends; 3) Adding a crystal stone to the wrapped bead circle; 4) Creating a spiral wire ring and attaching it to the bead assembly; 5) Opening and wrapping the spiral ring loops; 6) Trimming and hiding the wire ends. Tools include headpins, wire, pliers, mandrels and cutters.
This document discusses soldering and cleaning processes for high-performance printed circuit boards. It covers topics like solder alloy composition, flux usage, solder paste characteristics, and post-assembly cleaning requirements. It also addresses environmentally-friendly circuit board materials and processes, including pollution prevention strategies like reducing water usage and implementing recycling programs.
Palestra 4 - Avanços em tecnologia de fresamento: do fresamento convencional ...senaimais
Advances in milling Technologies: from convencional milling to HSC.
Palestrante: Msc. Benedikt Gellissen - Instituto Fraunhofer de Tecnologias da Produção - FhG IPT - Alemanha
SSMA connectors are precision connectors that perform up to 40GHz. They are commonly used where smaller size and higher density are needed. Cmpter offers SSMA receptacles, adapters, and connectors for semi-rigid and flexible cable that can be customized for applications. SSMA connectors have excellent performance up to 40GHz, low VSWR and insertion loss, and rugged construction for reliability.
Alpha exactalloy Solder preforms for product and process improvementreginahuse
There is an Exactalloy™ preform in the rightshape and size to improve your assembly operation, product reliability and quality. Get Technical support from Krayden Regarding Alpha product and its proper application method.
Bodycote is a publicly traded company with over $1 billion in annual sales and over 10,000 employees across 200 locations in 36 countries. Their Silao, Mexico facility opened in 2007 and provides various heat treating services for automotive and industrial applications, including carburizing, carbonitriding, ferritic nitrocarburizing, and shot peening. The facility has atmospheric furnaces, low pressure carburizing systems, batch furnaces, and metallurgical testing capabilities. Bodycote invites customers to provide part details to obtain quotes for heat treating and surface enhancement services.
Hybrid processes combine multiple manufacturing technologies to overcome limitations of conventional machining. This presentation defines hybrid processes as combining active principles that significantly influence the machining process. It provides examples of hybrid technologies like vibration-assisted machining, laser-assisted machining, and combinations of EDM/ECM with other processes. The goal of hybrid processes is to enable machining of difficult materials more efficiently.
The document discusses high performance printed circuit boards. It defines key terms like laminates, glass transition temperature, and loss tangent. It describes various laminate materials like FR-4, bismaleimide triazine epoxy, polyimide, and PTFE, comparing their properties and costs. It also discusses microvias, multilayer circuit boards, and different processes for forming microvias. Finally, it covers substrates for RF and microwave systems, describing transmission lines and via structures used in high frequency applications.
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.
Re-Mining Item Associations: Methodology and a Case Study in Apparel Retailingertekg
Download Link > https://ertekprojects.com/gurdal-ertek-publications/blog/re-mining-item-associations-methodology-and-a-case-study-in-apparel-retailing/
Association mining is the conventional data mining technique for analyz-ing market basket data and it reveals the positive and negative associations between items. While being an integral part of transaction data, pricing and time information have not been integrated into market basket analy-sis in earlier studies. This paper proposes a new approach to mine price, time and domain related attributes through re-mining of association mining results. The underlying factors behind positive and negative relationships can be characterized and described through this second data mining stage. The applicability of the methodology is demonstrated through the analy-sis of data coming from a large apparel retail chain, and its algorithmic complexity is analyzed in comparison to the existing techniques.
Application of local search methods for solving a quadratic assignment proble...ertekg
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. Istanbul, Turkey.
Financial Benchmarking Of Transportation Companies In The New York Stock Exc...ertekg
Download Link > https://ertekprojects.com/gurdal-ertek-publications/blog/financial-benchmarking-of-transportation-companies-in-the-new-york-stock-exchange-nyse-through-data-envelopment-analysis-dea-and-visualization/
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.
Linking Behavioral Patterns to Personal Attributes through Data Re-Miningertekg
Download Link >https://ertekprojects.com/gurdal-ertek-publications/blog/linking-behavioral-patterns-to-personal-attributes-through-data-re-mining/
A fundamental challenge in behavioral informatics is the development of methodologies and systems that can achieve its goals and tasks, including be-havior pattern analysis. This study presents such a methodology, that can be con-verted into a decision support system, by the appropriate integration of existing tools for association mining and graph visualization. The methodology enables the linking of behavioral patterns to personal attributes, through the re-mining of colored association graphs that represent item associations. The methodology is described and mathematically formalized, and is demonstrated in a case study related with retail industry.
The Bullwhip Effect In Supply Chain Reflections After A Decadeertekg
Download Link > https://ertekprojects.com/gurdal-ertek-publications/blog/the-bullwhip-effect-in-supply-chain-reflections-after-a-decade/
A decade has passed since the publication of the two seminal papers by Lee, Padmanabhan and Whang (1997) that describes the “bullwhip effect” in supply chains and characterizes its underlying causes. The bullwhip phenomenon is observed in supply chains where the decisions at the subsequent stages of the supply chain are made greedily based on local information, rather than through coordination based on global information on the state of the whole chain. The first consequence of this information distortion is higher variance in purchasing quantities compared to sales quantities at a particular supply chain stage. The second consequence is increasingly higher variance in order quantities and inventory levels in the upstream stages compared to their downstream stages (buyers). In this paper, we survey a decade of literature on the bullwhip effect and present the key insights reported by researchers and practitioners. We also present our reflections and share our vision of possible future.
Optimizing Waste Collection In An Organized Industrial Region: A Case Studyertekg
This document summarizes a case study that optimizes industrial waste collection from 17 factories located in an organized industrial region in Turkey. The authors developed a mixed integer programming model to determine the optimal waste container locations and transportation routes to minimize total costs. They applied the model to real data from an industrial zone. The optimal solution selected 3 out of 5 candidate locations and had a minimum monthly cost of 70,338 Turkish Lira. The authors also created a visualization of the optimal supply chain network to provide additional insights into the solution.
Visual Mining of Science Citation Data for Benchmarking Scientific and Techno...ertekg
Download Link > https://ertekprojects.com/gurdal-ertek-publications/blog/visual-mining-of-science-citation-data-for-benchmarking-scientific-and-technological-competitiveness-of-world-countries/
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?
Teaching Warehousing Concepts through Interactive Animations and 3-D Modelsertekg
Download Link > https://ertekprojects.com/gurdal-ertek-publications/blog/teaching-warehousing-concepts-through-interactive-animations-and-3-d-models/
Teaching Warehousing Concepts through Interactive Animations and 3-D Models
Design Requirements For a Tendon Rehabilitation Robot: Results From a Survey ...ertekg
Download Link > https://ertekprojects.com/gurdal-ertek-publications/blog/design-requirements-for-a-tendon-rehabilitation-robot-results-from-a-survey-of-engineers-and-health-professionals/
Exoskeleton type finger rehabilitation robots are helpful in assisting the treatment of tendon injuries. A survey has been carried out with engineers and health professionals to further develop an existing finger exoskeleton prototype. The goal of the study is to better understand the relative importance of several design criteria through the analysis of survey results and to improve the finger exoskeleton accordingly. The survey questions with strong correlations are identified and the preferences of the two respondent groups are statistically compared. The results of the statistical analysis are interpreted and insights obtained are used to guide the design process. The answers to the qualitative questions are also discussed together with their design implications. Finally, Quality Function Deployment (QFD) has been employed for visualizing these functional requirements in relation to the customer requirements.
Rule-based expert systems for supporting university studentsertekg
Download Link > https://ertekprojects.com/gurdal-ertek-publications/blog/rule-based-expert-systems-for-supporting-university-students/
There are more than 15 million college students in the US alone. Academic advising for courses and scholarships is typically performed by human advisors, bringing an immense managerial workload to faculty members, as well as other staff at universities. This paper reports and discusses the development of two educational expert systems at a private international university. The first expert system is a course advising system which recommends courses to undergraduate students. The second system suggests scholarships to undergraduate students based on their eligibility. While there have been reported systems for course advising, the literature does not seem to contain any references to expert systems for scholarship recommendation and eligibility checking. Therefore the scholarship recommender that we developed is first of its kind. Both systems have been implemented and tested using Oracle Policy Automation (OPA) software.
Impact of Cross Aisles in a Rectangular Warehouse: A Computational Studyertekg
Download Link > https://ertekprojects.com/gurdal-ertek-publications/blog/impact-of-cross-aisles-in-a-rectangular-warehouse-a-computational-study/
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.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.
Visual and analytical mining of transactions data for production planning f...ertekg
Download Link > https://ertekprojects.com/gurdal-ertek-publications/blog/visual-and-analytical-mining-of-sales-transaction-data-for-production-planning-and-marketing/
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.
Encapsulating And Representing The Knowledge On The Evolution Of An Engineeri...ertekg
1) The document describes a methodology for encapsulating and representing knowledge about the evolution of an engineering system. It involves mathematical formalism to represent design steps, contradictions, goals and TRIZ principles.
2) A graph visualization is proposed to represent the design process, with nodes as possible TRIZ principles and colored nodes indicating principles selected at each step.
3) A database structure is outlined to store information on contradictions, principles, design steps and which principles were selected, along with explanations. This knowledge representation aims to guide design of similar products.
İndirmek için Bağlantı > https://ertekprojects.com/gurdal-ertek-publications/blog/depolama-sistemleri/
Depolar, ürünlerin dağıtımı sırasında kullanılan geçici stok noktalarıdır. Depolar, tedarik zincirlerinin hedeflenen amaçlar doğrultusunda çalışmasına ve lojistik faaliyetlerinin etkin yürütülmesine önemli katkıda bulunurlar. Depolar, üretim tesislerinin içinde veya yanında bulunabileceği gibi, ayrı, özel olarak inşa edilmiş yapılar halinde de kurulabilirler. Şekil 4.1’de, tipik bir deponun genel görünüşü sunulmaktadır. Malzeme/ürünler, bu tipik depoda raflarda depolanmakta, malzeme giriş çıkışları depo rampaları üzerinden gerçekleşmekte, yükleme/boşaltma işlemleri forklift olarak adlandırılan araçlar kullanılarak gerçekleştirilmektedir. Deponun yönetimi, Depo Yöneticisi (Warehouse Manager) ya da Depo Müdürüunvanını taşıyan bir lojistik uzmanı tarafından yürütülmektedir.
Statistical Scoring Algorithm for Learning and Study Skillsertekg
İndirmek için Bağlantı > https://ertekprojects.com/gurdal-ertek-publications/blog/statistical-scoring-algorithm-for-learning-and-study-skills/
This study examines the study skills and the learning styles of university students by using scoring method. The study investigates whether the study skills can be summarized in a single universal score that measures how hard a student works. The sample consists of 418 undergraduate students of an international university. The presented scoring was method adapted from the domain of risk management. The proposed method computes an overall score that represents the study skills, using a linear weighted summation scheme. From among 50 questions regarding to learning and study skills, the 30 highest weighted questions are suggested to be used in the future studies as a learning and study skills inventor. The proposed scoring method and study yield results and insights that can guide educators regarding how they can improve their students’ study skills. The main point drawn from this study is that the students greatly value opportunities for interaction with instructors and peers, cooperative learning and active engagement in lectures.
Competitive Pattern-Based Strategies under Complexity: The Case of Turkish Ma...ertekg
Download Link > https://ertekprojects.com/gurdal-ertek-publications/blog/competitive-pattern-based-strategies-under-complexity-the-case-of-turkish-managers/
This paper aims to augment current Enterprise Architecture (EA) frameworks to become pattern-based. The main motivation behind pattern-based EA is the support for strategic decisions based on the patterns prioritized in a country or industry. Thus, to validate the need for pattern-based EA, it is essential to show how different patterns gain priority under different contexts, such as industries. To this end, this chapter also reveals the value of alternative managerial strategies across different industries and business functions in a specific market, namely Turkey. Value perceptions for alternative managerial strategies were collected via survey, and the values for strategies were analyzed through the rigorous application of statistical techniques. Then, evidence was searched and obtained from business literature that support or refute the statistically-supported hypothesis. The results obtained through statistical analysis are typically confirmed with reports of real world cases in the business literature. Results suggest that Turkish firms differ significantly in the way they value different managerial strategies. There also exist differences based on industries and business functions. Our study provides guidelines to managers in Turkey, an emerging country, on which strategies are valued most in their industries. This way, managers can have a better understanding of their competitors and business environment, and can develop the appropriate pattern-based EA to cope with complexity and succeed in the market.
Download Link > https://ertekprojects.com/gurdal-ertek-publications/blog/modelling-the-supply-chain-perception-gaps/
This study applies the research of perception gap analysis to supply chain integration and develops a generic model, the 3-Level Gaps Model, with the goal of contributing to harmonization and integration in the supply chain. The model suggests that significant perception gaps may exist among supply chain members with regards to the importance of different performance criteria. The concept of the model is conceived through an empirical and inductive approach, combining the research discipline of supply chain relationship and perception gap analysis. First hand data has been collected through a survey across a key buyer in the motor insurance industry and its eight suppliers. Rigorous statistical analysis testified the research hypotheses, which in turn verified the validity and relevance of the developed 3-Level Gaps Model. The research reveals the significant existence of supply chain perception gaps at all three levels as defined, which could be the root-causes to underperformed supply chain.
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.
International Journal of Computational Engineering Research(IJCER)ijceronline
International Journal of Computational Engineering Research (IJCER) is dedicated to protecting personal information and will make every reasonable effort to handle collected information appropriately. All information collected, as well as related requests, will be handled as carefully and efficiently as possible in accordance with IJCER standards for integrity and objectivity
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.
Re-Mining Item Associations: Methodology and a Case Study in Apparel Retailingertekg
Download Link > https://ertekprojects.com/gurdal-ertek-publications/blog/re-mining-item-associations-methodology-and-a-case-study-in-apparel-retailing/
Association mining is the conventional data mining technique for analyz-ing market basket data and it reveals the positive and negative associations between items. While being an integral part of transaction data, pricing and time information have not been integrated into market basket analy-sis in earlier studies. This paper proposes a new approach to mine price, time and domain related attributes through re-mining of association mining results. The underlying factors behind positive and negative relationships can be characterized and described through this second data mining stage. The applicability of the methodology is demonstrated through the analy-sis of data coming from a large apparel retail chain, and its algorithmic complexity is analyzed in comparison to the existing techniques.
Application of local search methods for solving a quadratic assignment proble...ertekg
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. Istanbul, Turkey.
Financial Benchmarking Of Transportation Companies In The New York Stock Exc...ertekg
Download Link > https://ertekprojects.com/gurdal-ertek-publications/blog/financial-benchmarking-of-transportation-companies-in-the-new-york-stock-exchange-nyse-through-data-envelopment-analysis-dea-and-visualization/
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.
Linking Behavioral Patterns to Personal Attributes through Data Re-Miningertekg
Download Link >https://ertekprojects.com/gurdal-ertek-publications/blog/linking-behavioral-patterns-to-personal-attributes-through-data-re-mining/
A fundamental challenge in behavioral informatics is the development of methodologies and systems that can achieve its goals and tasks, including be-havior pattern analysis. This study presents such a methodology, that can be con-verted into a decision support system, by the appropriate integration of existing tools for association mining and graph visualization. The methodology enables the linking of behavioral patterns to personal attributes, through the re-mining of colored association graphs that represent item associations. The methodology is described and mathematically formalized, and is demonstrated in a case study related with retail industry.
The Bullwhip Effect In Supply Chain Reflections After A Decadeertekg
Download Link > https://ertekprojects.com/gurdal-ertek-publications/blog/the-bullwhip-effect-in-supply-chain-reflections-after-a-decade/
A decade has passed since the publication of the two seminal papers by Lee, Padmanabhan and Whang (1997) that describes the “bullwhip effect” in supply chains and characterizes its underlying causes. The bullwhip phenomenon is observed in supply chains where the decisions at the subsequent stages of the supply chain are made greedily based on local information, rather than through coordination based on global information on the state of the whole chain. The first consequence of this information distortion is higher variance in purchasing quantities compared to sales quantities at a particular supply chain stage. The second consequence is increasingly higher variance in order quantities and inventory levels in the upstream stages compared to their downstream stages (buyers). In this paper, we survey a decade of literature on the bullwhip effect and present the key insights reported by researchers and practitioners. We also present our reflections and share our vision of possible future.
Optimizing Waste Collection In An Organized Industrial Region: A Case Studyertekg
This document summarizes a case study that optimizes industrial waste collection from 17 factories located in an organized industrial region in Turkey. The authors developed a mixed integer programming model to determine the optimal waste container locations and transportation routes to minimize total costs. They applied the model to real data from an industrial zone. The optimal solution selected 3 out of 5 candidate locations and had a minimum monthly cost of 70,338 Turkish Lira. The authors also created a visualization of the optimal supply chain network to provide additional insights into the solution.
Visual Mining of Science Citation Data for Benchmarking Scientific and Techno...ertekg
Download Link > https://ertekprojects.com/gurdal-ertek-publications/blog/visual-mining-of-science-citation-data-for-benchmarking-scientific-and-technological-competitiveness-of-world-countries/
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?
Teaching Warehousing Concepts through Interactive Animations and 3-D Modelsertekg
Download Link > https://ertekprojects.com/gurdal-ertek-publications/blog/teaching-warehousing-concepts-through-interactive-animations-and-3-d-models/
Teaching Warehousing Concepts through Interactive Animations and 3-D Models
Design Requirements For a Tendon Rehabilitation Robot: Results From a Survey ...ertekg
Download Link > https://ertekprojects.com/gurdal-ertek-publications/blog/design-requirements-for-a-tendon-rehabilitation-robot-results-from-a-survey-of-engineers-and-health-professionals/
Exoskeleton type finger rehabilitation robots are helpful in assisting the treatment of tendon injuries. A survey has been carried out with engineers and health professionals to further develop an existing finger exoskeleton prototype. The goal of the study is to better understand the relative importance of several design criteria through the analysis of survey results and to improve the finger exoskeleton accordingly. The survey questions with strong correlations are identified and the preferences of the two respondent groups are statistically compared. The results of the statistical analysis are interpreted and insights obtained are used to guide the design process. The answers to the qualitative questions are also discussed together with their design implications. Finally, Quality Function Deployment (QFD) has been employed for visualizing these functional requirements in relation to the customer requirements.
Rule-based expert systems for supporting university studentsertekg
Download Link > https://ertekprojects.com/gurdal-ertek-publications/blog/rule-based-expert-systems-for-supporting-university-students/
There are more than 15 million college students in the US alone. Academic advising for courses and scholarships is typically performed by human advisors, bringing an immense managerial workload to faculty members, as well as other staff at universities. This paper reports and discusses the development of two educational expert systems at a private international university. The first expert system is a course advising system which recommends courses to undergraduate students. The second system suggests scholarships to undergraduate students based on their eligibility. While there have been reported systems for course advising, the literature does not seem to contain any references to expert systems for scholarship recommendation and eligibility checking. Therefore the scholarship recommender that we developed is first of its kind. Both systems have been implemented and tested using Oracle Policy Automation (OPA) software.
Impact of Cross Aisles in a Rectangular Warehouse: A Computational Studyertekg
Download Link > https://ertekprojects.com/gurdal-ertek-publications/blog/impact-of-cross-aisles-in-a-rectangular-warehouse-a-computational-study/
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.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.
Visual and analytical mining of transactions data for production planning f...ertekg
Download Link > https://ertekprojects.com/gurdal-ertek-publications/blog/visual-and-analytical-mining-of-sales-transaction-data-for-production-planning-and-marketing/
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.
Encapsulating And Representing The Knowledge On The Evolution Of An Engineeri...ertekg
1) The document describes a methodology for encapsulating and representing knowledge about the evolution of an engineering system. It involves mathematical formalism to represent design steps, contradictions, goals and TRIZ principles.
2) A graph visualization is proposed to represent the design process, with nodes as possible TRIZ principles and colored nodes indicating principles selected at each step.
3) A database structure is outlined to store information on contradictions, principles, design steps and which principles were selected, along with explanations. This knowledge representation aims to guide design of similar products.
İndirmek için Bağlantı > https://ertekprojects.com/gurdal-ertek-publications/blog/depolama-sistemleri/
Depolar, ürünlerin dağıtımı sırasında kullanılan geçici stok noktalarıdır. Depolar, tedarik zincirlerinin hedeflenen amaçlar doğrultusunda çalışmasına ve lojistik faaliyetlerinin etkin yürütülmesine önemli katkıda bulunurlar. Depolar, üretim tesislerinin içinde veya yanında bulunabileceği gibi, ayrı, özel olarak inşa edilmiş yapılar halinde de kurulabilirler. Şekil 4.1’de, tipik bir deponun genel görünüşü sunulmaktadır. Malzeme/ürünler, bu tipik depoda raflarda depolanmakta, malzeme giriş çıkışları depo rampaları üzerinden gerçekleşmekte, yükleme/boşaltma işlemleri forklift olarak adlandırılan araçlar kullanılarak gerçekleştirilmektedir. Deponun yönetimi, Depo Yöneticisi (Warehouse Manager) ya da Depo Müdürüunvanını taşıyan bir lojistik uzmanı tarafından yürütülmektedir.
Statistical Scoring Algorithm for Learning and Study Skillsertekg
İndirmek için Bağlantı > https://ertekprojects.com/gurdal-ertek-publications/blog/statistical-scoring-algorithm-for-learning-and-study-skills/
This study examines the study skills and the learning styles of university students by using scoring method. The study investigates whether the study skills can be summarized in a single universal score that measures how hard a student works. The sample consists of 418 undergraduate students of an international university. The presented scoring was method adapted from the domain of risk management. The proposed method computes an overall score that represents the study skills, using a linear weighted summation scheme. From among 50 questions regarding to learning and study skills, the 30 highest weighted questions are suggested to be used in the future studies as a learning and study skills inventor. The proposed scoring method and study yield results and insights that can guide educators regarding how they can improve their students’ study skills. The main point drawn from this study is that the students greatly value opportunities for interaction with instructors and peers, cooperative learning and active engagement in lectures.
Competitive Pattern-Based Strategies under Complexity: The Case of Turkish Ma...ertekg
Download Link > https://ertekprojects.com/gurdal-ertek-publications/blog/competitive-pattern-based-strategies-under-complexity-the-case-of-turkish-managers/
This paper aims to augment current Enterprise Architecture (EA) frameworks to become pattern-based. The main motivation behind pattern-based EA is the support for strategic decisions based on the patterns prioritized in a country or industry. Thus, to validate the need for pattern-based EA, it is essential to show how different patterns gain priority under different contexts, such as industries. To this end, this chapter also reveals the value of alternative managerial strategies across different industries and business functions in a specific market, namely Turkey. Value perceptions for alternative managerial strategies were collected via survey, and the values for strategies were analyzed through the rigorous application of statistical techniques. Then, evidence was searched and obtained from business literature that support or refute the statistically-supported hypothesis. The results obtained through statistical analysis are typically confirmed with reports of real world cases in the business literature. Results suggest that Turkish firms differ significantly in the way they value different managerial strategies. There also exist differences based on industries and business functions. Our study provides guidelines to managers in Turkey, an emerging country, on which strategies are valued most in their industries. This way, managers can have a better understanding of their competitors and business environment, and can develop the appropriate pattern-based EA to cope with complexity and succeed in the market.
Download Link > https://ertekprojects.com/gurdal-ertek-publications/blog/modelling-the-supply-chain-perception-gaps/
This study applies the research of perception gap analysis to supply chain integration and develops a generic model, the 3-Level Gaps Model, with the goal of contributing to harmonization and integration in the supply chain. The model suggests that significant perception gaps may exist among supply chain members with regards to the importance of different performance criteria. The concept of the model is conceived through an empirical and inductive approach, combining the research discipline of supply chain relationship and perception gap analysis. First hand data has been collected through a survey across a key buyer in the motor insurance industry and its eight suppliers. Rigorous statistical analysis testified the research hypotheses, which in turn verified the validity and relevance of the developed 3-Level Gaps Model. The research reveals the significant existence of supply chain perception gaps at all three levels as defined, which could be the root-causes to underperformed supply chain.
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.
International Journal of Computational Engineering Research(IJCER)ijceronline
International Journal of Computational Engineering Research (IJCER) is dedicated to protecting personal information and will make every reasonable effort to handle collected information appropriately. All information collected, as well as related requests, will be handled as carefully and efficiently as possible in accordance with IJCER standards for integrity and objectivity
IRJET- Effect of Soft Annealing on Copper, Brass and GunmetalIRJET Journal
The document analyzes the effect of soft annealing on copper, brass, and gunmetal samples. Rockwell hardness tests were performed before and after annealing samples at 850°C. Brass was found to be the hardest before annealing, while copper was hardest after annealing. Microstructure images showed grain refinement in copper after annealing but no visible changes in brass. Gunmetal samples developed cracks and pores after annealing. Wear tests found copper to be most resistant to wear, followed by brass, with gunmetal being the least resistant due to cracks and pores developed during annealing. In conclusion, annealing increased ductility and workability while decreasing hardness, with copper retaining higher hardness and wear resistance compared to brass and gunmetal after annealing.
This document provides an overview of continuous casting of aluminium, specifically focusing on strip casting and wire bar casting technologies. It describes the basic principles of continuous casting, including key features like using rotating drums or belts to form a mould for molten aluminium. It discusses different types of casters like twin drum casters, single drum casters, and those using belts or blocks. It also addresses properties of continuously cast products and their behavior in further processing like rolling. The document aims to give readers an understanding of the possibilities and limitations of continuous casting aluminium.
This chapter discusses principles of solidification as they apply to pure metals. It examines mechanisms of solidification such as nucleation and growth, and applications like welding. The chapter outlines solidification processes, defects, and casting techniques. It provides examples calculating critical nucleation radius, redesigning a casting, and designing a riser. Diagrams of cooling curves and cast microstructures are also presented.
International Journal of Engineering Research and DevelopmentIJERD Editor
Electrical, Electronics and Computer Engineering,
Information Engineering and Technology,
Mechanical, Industrial and Manufacturing Engineering,
Automation and Mechatronics Engineering,
Material and Chemical Engineering,
Civil and Architecture Engineering,
Biotechnology and Bio Engineering,
Environmental Engineering,
Petroleum and Mining Engineering,
Marine and Agriculture engineering,
Aerospace Engineering.
This document reviews the use of carbon nanotubes to improve the surface finish of the electrical discharge machining (EDM) process. EDM is commonly used to machine hard materials but often results in poor surface finish with cracks and defects. Researchers have attempted to address this by adding powders like aluminum or silicon carbide to the dielectric fluid. More recently, carbon nanotubes have been explored due to their excellent thermal conductivity and electrical properties. When added to the dielectric fluid, carbon nanotubes are found to disperse the discharge energy more uniformly and reduce cracks and defects on machined surfaces. Surface roughness is improved by 70% or more and machining time is reduced. Carbon nanotubes show better results than other pow
In electrical discharge machining (EDM), Copper
and Graphite are commonly used as electrode (tool) materials.
EDM process is based on thermoelectric energy between an
electrode and workpiece. In this paper, the effect of electrode wear
rate (EWR) in 202 stainless steel is observed. Copper Electrode is
used as tool material and SS-202 is used as workpiece. Copper
electrode possess high structural integrity, so it can produce very
fine surface finishes, even without special polishing circuits.
The document discusses advanced ceramic substrates for microelectronic systems. It describes desired substrate properties such as high electrical resistivity and thermal conductivity. It also discusses common ceramic materials used as substrates like silicon carbide and aluminum nitride and their fabrication methods. The document outlines the definitions, thermal, mechanical, and electrical properties to consider for ceramic substrates. It also covers metallization techniques for ceramic substrates, such as thick film and thin film processes.
This document summarizes a seminar presentation on optimizing the wire electrical discharge machining (WEDM) process for machining Inconel alloy 800HT. The presentation discusses using Taguchi-Grey relation analysis to optimize the WEDM process parameters when using Victrol 4003 mixed electric discharge machining. The objectives are to maximize material removal rate and minimize surface roughness. The methodology involves designing experiments using Taguchi methods, measuring responses, and analyzing the data using Grey relation analysis. The expected outcomes include determining optimal process parameters and analyzing surface integrity after machining.
Non Linear Finite Element Method of Analysis of Reinforced Concrete Deep BeamIJMER
ABSTRACT: This paper describes analysis of deep beams subjected to two point loading with three different L/D ratios
(1.5, 1.6, 1.71) using Non-linear Finite element method (ANSYS 9.0 software) in order to investigate the stress and strain
distribution pattern at mid-section of the beam. In ANSYS 9.0 software, SOLID 65 and LINK 8 element represent concrete
and reinforcing steel bars. Non-linear material properties were defined for both elements .Using ANSYS software Flexural
Strains and Stresses were determined at mid-section of the beam and shear stresses near the support of the beam. Also the
failure crack-patterns were obtained. Variation of flexural stresses and strains, shear stresses were plotted. It was found that
the smaller the span/depth ratio, the more pronounced is the deviation of strain pattern at mid-section of the beam.
Keywords: Deep Beam, Non-Linear Finite element method, ANSYS 9.0. L/D (Span to depth).
This document describes a study on preparing nickel-coated aluminum through an electroless deposition technique. Sintered aluminum samples were developed using powder metallurgy. Nickel was deposited from an aqueous nickel chloride solution onto the sintered aluminum substrates without external electricity. The coating process was studied at different temperatures. Characterization of the coated samples found uniform nickel distribution at room temperature. XRD analysis confirmed the presence of both nickel and aluminum phases. Coating improved the surface properties by decreasing porosity and increasing hardness. The nickel-coated aluminum samples exhibited magnetic properties.
477 report spiral welded pipe Erdi Karaçal Mechanical Engineer University of...Erdi Karaçal
This document presents a feasibility study for a proposed spiral pipe factory. It analyzes the market potential, discusses suitable factory locations, and outlines the pipe manufacturing process. The process involves edge milling coil, forming it into a spiral, submerged arc welding, cutting, testing via ultrasonic and hydrostatic methods, and external/internal coating. A cost analysis is also presented, outlining machinery needs, fixed costs, labor costs, and expected financials. The proposed location is Osmaniye Industrial Zone in Turkey due to proximity to coil suppliers and transport routes.
This document discusses the key steps in integrated circuit fabrication:
1. Layering involves adding thin layers of materials like oxide, nitride and polysilicon through grown or deposited processes.
2. Patterning uses photolithography and etching to selectively expose layers for deposition, doping or etching according to the circuit design.
3. Doping introduces electrically active impurities through techniques like thermal diffusion or ion implantation to create semiconductor devices.
Fabrication process of integrated circuitCIKGUNURUL4
This document discusses the key steps in integrated circuit fabrication:
1. Layering involves adding thin layers of materials like oxide, nitride and polysilicon through grown or deposited processes.
2. Patterning uses photolithography and etching to selectively expose layers for deposition, doping or etching according to the circuit design.
3. Doping introduces electrically active impurities through techniques like thermal diffusion or ion implantation to create semiconductor devices.
IRJET- Quality Improvement of Ductile Iron Casting by Thermal AnalysisIRJET Journal
The document discusses using thermal analysis to improve the quality of ductile iron castings by reducing shrinkage defects. It presents the results of an experiment where cooling curves were recorded for ductile iron castings with different section thicknesses. Nine castings were produced with variations in chemical composition, inoculation amount, and pouring temperature. The cooling curves were analyzed to understand the solidification behavior and identify conditions that led to shrinkage. The results showed that thermal analysis is effective for controlling melt quality in ductile iron and avoiding shrinkage, with nil undercooling indicating sufficient inoculation for a given composition and thickness.
Experimental Analysis on Wire Arc Additive ManufacturingIRJET Journal
The document summarizes an experimental analysis of wire arc additive manufacturing (WAAM) of mild steel. Microscopic analysis found the deposition occurred in both parallel and perpendicular orientations, with grain structures including equiaxed and columnar formations. Hardness testing found values between 18-47 kg/mm2, while mechanical testing found maximum tensile and yield strengths of 25.05 and 560.69 MPa respectively in the through deposition direction. The study aims to optimize the WAAM process by analyzing defects like hot cracking and gas porosity at different deposition parameters.
Integrated Circuit (IC) Manufacture
- Slicing the Silicon ingot
- Fabrication of IC’s (Lithography, Sputtering, diffused junction, …)
- Testing each IC on the slice
- Dicing (cutting each chip out with a diamond saw)
- Packaging
This lab experiment examines the metal forming process of bending through V-bending operations. Students will bend different material sheets, including brass, aluminum, and steel alloys, using dies with varying bend radii. They will observe how material properties like ductility affect the minimum bend radius and amount of springback. Data on bend radius, springback, and bending force will be collected, analyzed, and plotted on a graph showing the relationship between ductility and bend radius. Students will also calculate and compare bending forces for hardened versus annealed brass. The results will help understand how material properties influence factors like bend tolerance in metal forming applications.
IJERD (www.ijerd.com) International Journal of Engineering Research and Devel...IJERD Editor
This document summarizes a study that used finite element analysis to simulate sheet metal crimping processes. The study modeled the crimping of aluminum sheet metal with different angles of inclination. Results showed reducing crimp load requirements and improving contact with increasing inclination angles from 10 to 30 degrees. A three-layer crimp formation was also achieved through adjustments to better enable leak-proof joints. The finite element analysis provided insights into reducing stresses, loads, and material needs for more efficient and higher quality crimping processes.
Similar to Simulation Modeling For Quality And Productivity In Steel Cord Manufacturing (20)
Optimizing the electric charge station network of EŞARJertekg
Download Link > https://ertekprojects.com/gurdal-ertek-publications/blog/optimizing-the-electric-charge-station-network-of-esarj/
In this study, we adopt the classic capacitated p-median location model for the solution of a network design problem, in the domain of electric charge station network design, for a leading company in Turkey. Our model encompasses the location preferences of the company managers as preference scores incorporated into the objective function. Our model also incorporates the capacity concerns of the managers through constraints on maximum number of districts and maximum population that can be served from a location. The model optimally selects the new station locations and the visualization of model results provides additional insights.
Competitiveness of Top 100 U.S. Universities: A Benchmark Study Using Data En...ertekg
Download Link > https://ertekprojects.com/gurdal-ertek-publications/blog/benchmark-study-using-data-envelopment-analysis/
This study presents a comprehensive benchmarking study of the top 100 U.S. Universities. The methodologies used to come up with insights into the domain are Data Envelopment Analysis (DEA) and information visualization. Various approaches to evaluating academic institutions have appeared in the literature, including a DEA literature dealing with the ranking of universities. Our study contributes to this literature by the extensive incorporation of information visualization and subsequently the discovery of new insights.
Industrial Benchmarking through Information Visualization and Data Envelopmen...ertekg
Download Link > https://ertekprojects.com/gurdal-ertek-publications/blog/industrial-benchmarking-through-information-visualization-and-data-envelopment-analysis-a-new-framework/
We present a benchmarking study on the companies in the Turkish food industry based on their financial data. Our aim is to develop a comprehensive benchmarking framework using Data Envelopment Analysis (DEA) and information visualization. Besides DEA, a traditional tool for financial benchmarking based on financial ratios is also incorporated. The consistency/inconsistency between the two methodologies is investigated using information visualization tools. In addition, k-means clustering, a fundamental method from machine learning, is applied to understand the relationship between k-means clustering and DEA.
Risk Factors and Identifiers for Alzheimer’s Disease: A Data Mining Analysisertekg
Download Link > https://ertekprojects.com/gurdal-ertek-publications/blog/risk-factors-and-identifiers-for-alzheimers-disease-a-data-mining-analysis/
The topic of this paper is the Alzheimer’s Disease (AD), with the goal being the analysis of risk factors and identifying tests that can help diagnose AD. While there exists multiple studies that analyze the factors that can help diagnose or predict AD, this is the first study that considers only non-image data, while using a multitude of techniques from machine learning and data mining. The applied methods include classification tree analysis, cluster analysis, data visualization, and classification analysis. All the analysis, except classification analysis, resulted in insights that eventually lead to the construction of a risk table for AD. The study contributes to the literature not only with new insights, but also by demonstrating a framework for analysis of such data. The insights obtained in this study can be used by individuals and health professionals to assess possible risks, and take preventive measures.
Download Link > https://ertekprojects.com/gurdal-ertek-publications/blog/text-mining-with-rapidminer/
The goal of this chapter is to introduce the text mining capabilities of RAPIDMINER through a use case. The use case involves mining reviews for hotels at TripAdvisor.com, a popular web portal. We will be demonstrating basic text mining in RAPIDMINER using the text mining extension. We will present two different RAPIDMINER processes, namely Process01 andProcess02, which respectively describe how text mining can be combined with association mining and cluster modeling. While it is possible to construct each of these processes from scratch by inserting the appropriate operators into the process view, we will instead import these two processes readily from existing model files. Throughout the chapter, we will at times deliberately instruct the reader to take erroneous steps that result in undesired outcomes. We believe that this is a very realistic way of learning to use RAPIDMINER, since in practice, the modeling process frequently involves such steps that are later corrected.
Supplier and Buyer Driven Channels in a Two-Stage Supply Chainertekg
Download Link > https://ertekprojects.com/gurdal-ertek-publications/blog/supplier-and-buyer-driven-channels-in-a-two-stage-supply-chain/
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.
Download Link > https://ertekprojects.com/gurdal-ertek-publications/blog/a-tutorial-on-crossdocking/
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.
Demonstrating Warehousing Concepts Through Interactive Animationsertekg
Download Link > https://ertekprojects.com/gurdal-ertek-publications/blog/demonstrating-warehousing-concepts-through-interactive-animations/
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.
A Framework for Visualizing Association Mining Resultsertekg
Download Link > https://ertekprojects.com/gurdal-ertek-publications/blog/a-framework-for-visualizing-association-mining-results/
Association mining is one of the most used data mining techniques due to interpretable and actionable results. In this study we pro-pose a framework to visualize the association mining results, speci¯cally 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 sug-gest how they can be used as basis for decision making in retailing.
Application of the Cutting Stock Problem to a Construction Company: A Case Studyertekg
Download Link > https://ertekprojects.com/gurdal-ertek-publications/blog/application-of-the-cutting-stock-problem-to-a-construction-company-a-case-study/
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.
Benchmarking The Turkish Apparel Retail Industry Through Data Envelopment Ana...ertekg
Download Link > https://ertekprojects.com/gurdal-ertek-publications/blog/benchmarking-the-turkish-apparel-retail-industry-through-data-envelopment-analysis-dea-and-data-visualization/
This paper presents a benchmarking study of the Turkish apparel retailing industry. We have applied the Data Envelopment Analysis (DEA) methodology to determine the efficiencies of the companies in the industry. In the DEA model the number of stores, number of corners, total sales area and number of employees were included as inputs and annual sales revenue was included as the output. The efficiency scores obtained through DEA were visualized for gaining insights about the industry and revealing guidelines that can aid in strategic decision making.
An Open Source Java Code For Visualizing Supply Chain Problemsertekg
Download Link > https://ertekprojects.com/gurdal-ertek-publications/blog/an-open-source-java-code-for-visualizing-supply-chain-problems/
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.
This paper discusses fundamental issues in dairy logistics in a tutorial format. We summarize findings of more than twenty student groups who carried out independent literature surveys and interviewed professionals in the industry. The critical issues in carrying out dairy products logistics, the logistics strategies that are employed by dairy producers in the world and some newly introduced products in the industry and in what ways the introduction of these new products changes the logistics operations are pointed out. The importance of hygiene, cooling, time, humidity, cost, distance, flexibility and meeting the demand is emphasized under the subtitle of critical issues. Except those critical issues, there are some others like short shelf life, quality, emulsion, pasteurization, UHT which depend on the characteristics of the milk and milk products. Logistics strategies in dairy industry are studied by dividing it into two subtitles: the ones that are used in the world and the ones in Turkey. A benchmarking between Turkey and the world is also included at the end. As the variety of milk and milk products increase day by day, the new ingredients of new products also affects the transportation plans. Those impacts are also discussed as a part of our paper. Some descriptive drawings and figures are also embodied. Throughout this paper, only the production, warehousing and transportation of milk, cheese, yoghurt, and similar dairy products are discussed. Ice-cream especially is set out of the scope as it completely differs from actual dairy products as milk, cheese and yoghurt in the means of production and distribution.
Download Link > https://ertekprojects.com/gurdal-ertek-publications/blog/a-taxonomy-of-logistics-innovations/
In this paper we present a taxonomy of supply chain and logistics innovations, which is based on an extensive literature survey. Our primary goal is to provide guidelines for choosing the most appropriate innovations for a company, such that the company can outrun its competitors. We investigate the factors, both internal and external to the company, that determine the applicability and effectiveness of the listed innovations. We support our suggestions with real world cases reported in literature.
Innovation in Product Form And Function: Customer Perception Of Their Valueertekg
Download Link > https://ertekprojects.com/gurdal-ertek-publications/blog/innovation-in-product-form-and-function-customer-perception-of-their-value/
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Developing Competitive Strategies in Higher Education through Visual Data Miningertekg
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Information visualization is the growing field of computer science that aims at visually mining data for knowledge discovery. In this paper, a data mining framework and a novel information visualization scheme is developed and applied to the domain of higher education. The presented framework consists of three main types of visual data analysis: Discovering general insights, carrying out competitive benchmarking, and planning for High School Relationship Management (HSRM). In this paper the framework and the square tiles visualization scheme are described and an application at a private university in Turkey with the goal of attracting bright-est students is demonstrated.
Kimya Sanayinde Su Tasarrufu İçin Karar Destek Sistemi ertekg
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Enhancing Adoption of AI in Agri-food: Introduction
Simulation Modeling For Quality And Productivity In Steel Cord Manufacturing
1. Türkseven and Ertek
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.). Pro-
ceedings of 2003 Winter Simulation Conference. Institute of Electrical and Electronics Engi-
neers (IEEE), Piscataway, New Jersey.
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.
SIMULATION MODELING FOR QUALITY AND PRODUCTIVITY
IN STEEL CORD MANUFACTURING
Can Hulusi Türkseven Gürdal Ertek
School of Industrial Engineering Faculty of Engineering and Natural Sciences
Purdue University Sabancı University
315 N. Grant Street Orhanli, Tuzla, 34956
West Lafayette, IN 47907-2023, U.S.A. Istanbul, TURKEY
2. Türkseven and Ertek
ABSTRACT
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 pro-
duction 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.
1 INTRODUCTION
Steel cord is typically used as the main reinforcement material in manufacture of steel radial
tires. It strengthens the tire to provide fuel savings, long mileage, safety and comfort. The
manufacture of steel cord takes place through continuous processes where wire semi-products
are stored on discrete inventory units, namely “spool”s (Figure 1). The steel cord plant is oper-
ated with multiple –possibly conflicting- objectives, both quality related (ex: minimizing the
number of final spools containing knot defects) and productivity related (ex: increasing
throughput). Modeling this type of manufacturing requires special considerations applicable to
a narrow scope of industries. One such consideration is the reversal of the wire wound on the
spools at each bunching operation. Manufacturing systems with similar operating characteris-
tics include cable manufacturing (electric/energy/fiber-optic), nylon cord manufacturing, cop-
per rod manufacturing.
Literature on steel cord manufacturing is not extensive, since this is a very specialized type
of manufacturing, and the systems required are produced and installed by only a handful of
companies in the world. We refer the interested readers to the following two studies: Thomas
et al. (2002) report improvement of operations in a steel cord manufacturing company using
simulation. Mercankaya (2003) develops an optimization-based decision support system for
steel cord manufacturing.
We first describe the manufacturing process and outline research objectives. After discuss-
ing various modeling approaches for possible configurations and discussing the relevance of
simulation modeling, we describe the simulation model, including inputs, decision variables,
3. Türkseven and Ertek
ouputs and results obtained. We conclude with a discussion of future research areas in produc-
tion planning for the described systems.
Figure 1. Spool on which Wire is Wound
2 THE MANUFACTURING PROCESS
In steel cord manufacturing incoming raw material, the “steel rod wire”, is thinned into “fila-
ment”s which are used in successive bunching operations to construct the “steel cord” final
products (Figure 2). Between every bunching operation, the intermediate wire products are
wound onto spools of varying capacities (in the scale of thousands of meters). Steel rod wire
enters the steel cord plant with a radius of ~2.5mm and passes through dry drawing and wet
drawing, accompanied with other operations (including chemical processes such as copper and
zinc plating) to produce filaments with a radius of ~0.2mm. Filaments coming out of wet-
drawing are wound on spools and are referred to as “payoff”. Payoff becomes the raw material
for bunching and spiralling operations. At each bunching operation, bunched wires enter as
“core” to be bunched with a new layer of payoff (filaments) to form “take-up”. The “take-up” in
turn becomes the “core” for the following bunching operation (Figure 3).
4. Türkseven and Ertek
Begin Production
Dry drawing I & II Copper plating
Steel wire rod
Annealing Zinc plating
Cold air bath Wet drawing
RESEARCH FOCUS
Cold water bath Bunching Filament
Acidic solution Spiralling
Basic solution Packaging Steel cord
End production
to Copper plating
Figure 2. Production Processes in Steel Cord Manufacturing
Steel wire rod
Operation
(raw material)
Drawing
Filament (payoff)
Core
Bunching 1
Spiral filament
11 12 1
8 1 10 2
3 7 2
Bunching 2 Bunching 3 9 3
2 1 & Spiralling
6 3
8 4
3x0.2 5 4
7 6 5
Bunched 3+8x0.2
steel wire Bunched Final product
steel wire (construction)
3+8+12x0.2+1+1
Figure 3. Cross-section of 3+8+12x0.2+1 Construction at Successive Bunching Operations
5. Türkseven and Ertek
In each bunching operation the take-up consumes a pay-off longer than its own length, ac-
cording to a “usage factor”. For example, in a bunching operation with a usage ratio of 0.9,
100000 meters of payoff bunches with 90000 meters of core to produce 90000 meters of take-
up. As the product advances along the production line, its thickness increases and thus it takes
a longer payoff to cover the take-up; i.e. the usage ratio decreases. Input ratios are discussed
with other input parameters in Section 5.
The final steel cord product is obtained by spiralling a single filament after the final bunch-
ing operation, and is referred to as “construction”. Figure 3 illustrates the cross-section of the
wire semi-products at various bunching stages in manufacturing of construction
“3+8+12x0.2+1”. The naming convention for labeling constructions (and semi-product
bunched wires) uses a “+” sign to denote each additonal bunching operation. The construction
“3+8+12x0.2+1” is obtained by bunching 3 filaments of length 0.2mm in the first bunching op-
eration, then 8 filaments, and then 12 filaments at 0.2mm, followed by a single spiralled fila-
ment.
Despite product variety (possibly in the scale of hundreds), we focus in our research on
production of a particular construction and analyze quality and productivity issues for that sin-
gle final product. Our approach can be validly applied in analysis and improvement of steel
cord plants where a particular construction constitutes a major share of the production load or
is of primary importance for another reason.
As the spool of core and spools of payoff are used in a bunching operation, any of the spools
may run out first. The time it takes for this run-out is a function of the spool lengths and pro-
duction rates of the machines, besides other factors, some of which are discussed below. As
run-out takes place, the bunching machine gradually slows down and finally stops. A setup is
performed by a skilled operator to feed the next spool with the same kind of wire (core or pay-
off) into the machine. Payoff or core spool is tied at the wire location where the machine had
stopped, and production in that machine restarts. Since the stopping takes place gradually, a
certain amount of wire is typically wasted at every “change-over”. This tying of changed spools
results in a knot, which is an undesired situation. When the take-up spool (the spool on which
the semi-product wire out of a bunching operation is wound) is completely full, a change of
take-up is performed. Besides knots due to spool changes, “wire fractures”, seemingly random
6. Türkseven and Ertek
breaks of the wire due to structural properties, may also result in considerable number of addi-
tional knots. By tagging an information card on each spool the locations of knots can be rec-
orded. If the sources of knots (whether they are due to changeovers or fractures) are not rec-
orded, the resulting data would not be perfectly valid from a statistical point of view.
After the spiralling operation the steel cord is cut into specified lengths and wound onto fi-
nal spools, which are eventually packaged for customers. Tire manufacturers prefer that the
spools with the final cuts of steel cords contain no knots at all. Final spools that contain knots,
namely “rejected spools”, are classified as second quality and are sold at a very low price.
Therefore, it is an important management objective to decrease the number of knots and the
number of rejected spools.
The motivation of our research has been to identify improved operating policies, specifically
“optimal” spool lengths for each bunching operation, such that quality and productivity are
improved. Both of these two performance measures can be improved if the number of rejected
spools (spools containing knots) is reduced.
3 MODELING APPROACHES
In this section we discuss under what conditions simulation is a suitable modeling approach
for steel cord manufacturing and discuss various modeling issues. Typically the steel cord final
product is obtained after more than one bunching operation. For example, the construction
3+8+12x0.2+1 goes through 3 successive bunching operations and a final spiralling operation
(Figure 3). If machines of all bunching operations had the same cycle times connected serially,
and/or if random fractures were negligible, modeling the steel cord manufacturing process
would be a fairly simple task. For now, we assume that fracture knots constitute a minor por-
tion of the knots and can be ignored. In Section 4 we provide a detailed discussion of wire frac-
tures and describe approaches to validate data collected on them. We consider three cases that
correspond to various manufacturing settings, as illustrated in Figure 4.
In Case 1, we assume that each successive bunching operation is connected serially, and the
take-up (output wire) of a bunching operation is directly fed into the next one as core (input
wire) without any work-in-process spool inventory. The quality and productivity of this system
7. Türkseven and Ertek
would be very high, as production takes place continously except the final cuts. The quality
output of this hypothetical system is 100% and constitutes an upper bound on quality perfor-
mance of a real-world plant.
In Case 2, we assume that in-process inventories are stored on spools, and the serial nature
of Case 1 is kept. In this type of a system, knots do occur due to spool changes, yet knot loca-
tions at the end of bunching processes can be computed easily as multiples of spool lengths.
From these locations, the number of spools containing knots can be computed (Figure 5). We
can apply search algorithms to find spool lengths that minimize the number of rejected final
spools.
Case 3 is much more representitive of how steel cord manufacturing takes place in the real
world. Since machine production rates vary for different bunching operations, the numbers of
machines at each bunching operation are typically different. Work-in-process wires are stored
on spools, which are queued before the next set of bunching machines. For operational sim-
plicity, operators use a FIFO (First In First Out) queueing discipline in selecting the next spool
to enter bunching operations. It is extremely difficult to identify mathematically the order in
which spools are queued. Operator times, number of knots, knot locations, heuristic operating
policies (described in Section 6), the current state of the spools in the system, machine speeds
and other factors all affect the time it takes to complete a take-up spool. A linear programming
based model that takes these factors as parameters can be questioned with respect to validity,
as the constraints to reflect fairly complex nature of operations would require definition of a
large number of variables, many of them integer. Therefore, we believe that simulation model-
ing is the best way to analyze the described system. The existence of wire fractures only
strengthens this conclusion.
8. Türkseven and Ertek
CASE 1
Bunching 1 Bunching 2 Bunching 3
CASE 2
Bunching 1 Bunching 2 Bunching 3
CASE 3
Bunching 1 Bunching 2 Bunching 3
Bunching 1 Bunching 2 Bunching 3
Bunching 2 Bunching 3
Bunching 3
Figure 4. Various Manufacturing Scenarios which Require Different Modeling Approaches
4 MODELING WIRE FRACTURES
Wire fractures may constitute a significant percentage of all the knots, depending on the quali-
ty of incoming steel rod wire, heterogeneity caused by dry drawing processes, the plant envi-
ronment, machine characteristics, and other factors. As opposed to knots from change-overs,
which may be controlled –at least to some degree- through scheduling, wire fractures are un-
controllable. Since the frequency and locations of knots have great impact on quality and
productivity, one would ask the essential question of whether any patterns exist in wire frac-
ture locations. As part of our study, we collected this data from bunching machines in a par-
ticular steel cord plant and carried out basic statistical analysis. The data collected gives the lo-
cations of wire fractures in spools entering the final bunching operation.
9. Türkseven and Ertek
Spool length Spool length Spool length
for Bunching 1 for Bunching 2 for Bunching 3
xx xx xx x x x x xx x xx x xx x x x xx xxx
Steel cord construction
Figure 5. Locations of Knots in Case 2. The x Signs Denote the Knots Due to Change-overs. The
Intervals Shown in Brackets Correspond to Lengths of Work-in-Process Spools, and Are
Decision Variables in the Simulation Model.
Fracture locations have been thought to be related to the location of previous fractures, the lo-
cations of previous knots, core and payoff lengths. Production specialists suggested that these
issues do not affect the fractures. It was tested if fracture locations and frequency followed any
distribution. However, statistical analysis of the data did not suggest any patterns. Fracture lo-
cations have been assumed random (uniform distribution) in the simulation model. Thus, in-
ter-fracture distances are assumed to follow exponential distribution and the number of frac-
tures on unit length of wire is assumed to follow poisson distribution. In addition to a known
historical average value for the percentage of fractures, an estimate can also be obtained from a
sample collected during a particular time interval. One important question is whether the col-
lected data agrees with the patterns observed historically. This can be formulated as a statisti-
cal null-hypothesis and tested using statistical techniques.
10. Türkseven and Ertek
5 SIMULATION MODEL
5.1 Description
In the simulation, the number of rejected spools (a measure of both quality and productivity) is
computed given a set of spool lengths. Through grid-search on spool lengths, the optimal spool
lengths can be determined.
The optimal spool lengths are constrained to be within a certain percentage of the current
spool lengths. This constraint is imposed by plant managers as a result of the strategy of mak-
ing gradual changes over time, as opposed to rushing in radical changes in short time periods.
One other reason for such constraints is the impact on other operational measures. For exam-
ple, selecting the spool lengths that are too short would lead to prohibitively frequent payoff or
core changes, and increased operator costs.
Some production issues are almost unique to this particular type of manufacturing: An ex-
ample is that the locations of knots are reversed at every spool change. When a wound spool of
length h with knot locations (k1, k2, ..., kn) is fed into the bunching operation, the unwinding re-
sults in knot locations (h-kn, ..., h-k2, h-k1).
5.2 Implementation
The simulation was programmed in C++ language, and takes ~1 minute running time to com-
pute performance measures for a 10 ton production schedule (10 simulation experiments are
performed). We preferred programming with a general-purpose language, as there are com-
plexities (ex: reversing of knot locations at bunching operations) that would be next to impos-
sible to reflect using spreadsheets and would have to be custom-programmed if a simulation
language or modeling software were used.
11. Türkseven and Ertek
5.3 Model Inputs, Decision Variables and Outputs
Input Parameters:
Usage ratios: Ratio of take-up length to incoming payoff length at bunching and sprial-
ling operations. As the diameter of the wire increases, usage ratios decrease.
Wire densities: Linear density of wires on spools. These density values are used to con-
vert meter based calculations to tones, as calculations in the plant are carried out on a
weight basis.
Fracture ratios: Expected number of fractures per ton at each bunching operation.
Machine characteristics and quantities: Primarily the production rates, the rate at which
bunching machines bunch payoff filament on core to produce take-up.
Knotting time: The time it takes to restart the bunching process following a changeover
or fracture. This time is very dependent on the source of the knot and is in the scale of 1-
20 minutes.
Final spool length: The length of final cuts that are wound on spools to be packaged and
sent to tire manufacturers. These final cuts should be free of any knots.
Decision variables:
Spool lengths: The length of wires on the take up and payoff spools.
Outputs:
Number of accepted spools: The number of final spools that contain no knots.
Number of rejected spools: The number of final spools that contain knots.
Rejected wire length: The length of total rejected wire between knots, with a length
smaller than final cut length.
12. Türkseven and Ertek
Throughput time: Total time required to convert a given tonnage of payoff to steel cord.
6 RESULTS
The simulation program provides an accurate estimation of the system performance measures
given a particular setting. The results were validated with historical data from an existing steel
cord plant and the simulation model was observed to be valid. The program was used to de-
termine optimal spool lengths within a constrained search space. The accuracy of the simula-
tion can be increased through increasing simulation run lengths and number of simulations
and applying experimental design and output analysis techniques.
If there is inaccuracy in implementing any type of policy, the simulation can be used only as
a strategic testing tool to evaluate operating policies. Conclusions/suggestions obtained
through the simulation analysis of the analyzed manufacturing plant are as follows:
Some of the current operational rules used by operators are proven to be useful. One
such heuristic rule is performing a take-up change-over if only a few hundred meters
have remained on the bunching operation. This is a reasonable approach: If the final
spool length is greater than the remaining distance, winding the take-up completely
would result in a rejected final spool further down the production line. The simulation
model suggested that this indeed is a very helpful rule and should be implemented by all
the operators.
Feasibility of implementing dynamic control policies can be investigated. For example,
current FIFO rule for selecting among queued spools for bunching can be replaced by a
more sophisticated approach. The simulation model can be used to evaluate such
changes in operational policies. However, this would also require that measurements be
very accurate and that computers be placed at the plant floor.
13. Türkseven and Ertek
7 FUTURE RESEARCH
Even though the developed simulation model accurately reflects the characteristics of the ana-
lyzed plant, the model can be extended to include new features (such as compensating for ma-
chine break-downs) and operational rules (such as dynamic spool selection). Meanwhile, it can
also be used to test the economic feasibility of investing in new manufacturing technology, in-
cluding better machines. A long term project could be developing the current tool into a gener-
ic modeling environment to analyze systems with similar manufacturing characteristics.
ACKNOWLEDGMENTS
We would like to thank Mr. Turgut Uzer for allowing us to share our experiences with academ-
ia. We would like to thank the anonymous referee and the proceeding editors for their valuable
corrections and remarks.
REFERENCES
Thomas, J., J. Todi, and A. Paranjpe. Optimization of operations in a steel wire manufacturing
company. In Proceedings of 2002 Winter Simulation Conference, ed. E. Yucesan, C. H.
Chen, J. L. Snowdon, and J. M. Charnes, 1151-1156. Piscataway, New Jersey: Institute of
Electrical and Electronics Engineers.
Mercankaya, B. 2003. Sales forecasting and production planning of BEKSA in the context of
supply chain management. Sabanci University, Istanbul, Turkey.
AUTHOR BIOGRAPHIES
CAN H. TÜRKSEVEN is a graduate student at Purdue University. He received his B.S. from
Manufacturing Systems Engineering Program from Sabancı University, Istanbul, Turkey, in
2003.
14. Türkseven and Ertek
GÜRDAL ERTEK is an assistant professor at Sabancı University. He received his B.S. from
Industrial Engineering Department of Boğaziçi University, Istanbul, Turkey in 1994 and his
Ph.D. from School of Industrial and Systems Engineering at Georgia Institute of Technology,
Atlanta, GA, in 2001. His research areas include supply chain planning, material handling,
production planning and simulation analysis.