Mühendislik Fakültesi / Faculty of Engineering

Permanent URI for this collectionhttps://hdl.handle.net/11727/1401

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    Development of A Financial Performance Benchmarking Model for Corporate Firms
    (2015) Ic, Yusuf Tansel; Tekin, Muhtesem; Pamukoglu, Fazil Ziya; Yildirim, S. Erdinc; 0000-0001-9274-7467; AGE-3003-2022; AGQ-5008-2022; AAI-1081-2020
    In this study, we developed a financial performance evaluation model to rank the corporate firms of 24 sectors in the Turkish economy. The developed model is based on the financial ratiosand Technique for Order Preference by Similiarity to Ideal Solution (TOPSIS) approach. This model of ferscorporate firm's rating scores with respect to its competitors belonging to the same industry. The developed model is coded in Visual Basic and tested with real case studies. Financial performance evaluation rankings obtained from TOPSIS, Vise Kriterijumska Optimizacija I Kompromisno Resenje (VIKOR), Grey Relational Grade (GRA), and Multi-Objective Optimization on thebasis of Ratio Analysis (MOORA) methods were compared by using Spearman's rank correlation test. Based on the test results, it was found that the TOPSIS method is the most appropriate method for the evaluation of financial performance. An application is also provided in the paper for illustrative purposes.
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    A Decision Support System for Selection of Net-Shape Primary Manufacturing Processes
    (2014) Yurdakul, Mustafa; Arslan, Emre; Ic, Yusuf Tansel; Turkbas, O. Selim; https://orcid.org/0000-0001-9274-7467; AGE-3003-2022
    Developments in the capabilities of the manufacturing processes increased the number of processes that can produce a part within the requirements determined by its design and market research. The increased number of processes and unfamiliarity of manufacturing engineers to many new manufacturing processes forces the researchers to develop systematic process selection tools instead of depending on the accumulated human expertise only. In this paper, a net-shape primary manufacturing process selection decision support system (DSS), which is named PROSEL (PROcess SELection), is developed. The developed selection programme eliminates the unsuitable processes step by step by checking a part's material, annual production quantity, specified shape, thickness and presents the most economical process as the most appropriate net-shape primary process after a final cost analysis. The developed DSS is written in Visual Studio and tested with a great deal of real-life examples. It can be concluded from the tests that the programme provides the same or better primary manufacturing process selection decisions than the practical usage, and it is a very useful support tool for net-shape primary process selections.
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    A TOPSIS Based Design of Experiment Approach to Assess Company Ranking
    (2014) Ic, Yusuf Tansel; https://orcid.org/0000-0001-9274-7467; AGE-3003-2022
    Company ranking is a complex process in which multiple financial ratios are required to be considered simultaneously. Furthermore, the selection process of an appropriate credit applicant company has become more complex as the experts in the financial organizations have to assess a wide range of alternatives based on a set of conflicting financial criteria. This paper studies the application of a new approach, i.e., Design of Experiment and TOPSIS method (DoE-TOPSIS) together to make company raking as frequently encountered in the real-time financial environment. The developed model is tested by case studies and satisfactory results are obtained. In the case studies, the results obtained by using the combined DoE-TOPSIS method are almost corroborated by those derived from conventional multi attribute decision making (MADM) methods which prove the applicability, potentiality, simplicity and flexibility of this method in making company ranking. (C) 2013 Elsevier Inc. All rights reserved.
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    Multi-response Simulation Optimization Approach for The Performance Optimization of An Alarm Monitoring Center
    (2014) Simsek, Baris; Ic, Yusuf Tansel; https://orcid.org/0000-0001-9274-7467; AGE-3003-2022
    This study offers a multi-response simulation-optimization approach to optimize an Alarm Monitoring Center's performance. In this paper, the multi-response simulation-optimization application is firstly addressed in the Alarm Monitoring Center. Five performance criteria affect the performance of Alarm Monitoring Center and five factors, each of which has three control levels, are identified. The data belonging to the performance criteria, which are determined, are obtained with the help of the running scenarios combining with the factor levels using Taguchi design. Then, signals to the noise (S/N) ratios are calculated for these which are obtained from the performance data. A decision matrix is generated with S/N ratios; the TOPSIS method is used to transfer the multi-response problems into the single-response problems. The system improvement rate is also determined by finding the levels of factors to optimize the system using Taguchi's single response optimization methodology.(C) 2014 Elsevier Ltd. All rights reserved.
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    Development of A Graphical User Interface for Determining The Optimal Mixture Parameters of Normal Weight Concretes: A Response Surface Methodology Based Quadratic Programming Approach
    (2014) Simsek, Baris; Ic, Yusuf Tansel; Simsek, Emir H.; Guvenc, Ali Bilge; https://orcid.org/0000-0001-9274-7467; AGE-3003-2022
    The optimization of a normal weight concrete mixture proportions for determination of the desired concrete quality is an important issue for concrete manufacturers and users. In this study, the constrained quadratic programming methodology is based on meta-models developed by using response surface methodology for determining optimal normal weight concrete mixture proportions. We developed a graphical user interface to take the burden of numerous experiments and complex mathematical calculations away from laboratory experts and manufacturers. However, we developed a graphical user interface based on MATLAB (R) toolbox which allows performing optimization of normal weight concrete mixture proportions interactively. The GUI was tested through real case studies and satisfactorily results were obtained. The results showed that developed graphical user interface was functional, effective and flexible in solving the optimization problems of normal weight concrete mixture proportions. (C) 2014 Elsevier B.V. All rights reserved.
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    Application of Cellular Manufacturing and Simulation Approaches for Performance Improvement in an Aerospace Company's Manufacturing Activities
    (2019) Ic, Yusuf Tansel; Yurdakul, Mustafa; Gulsen, Mehmet; Dalcan, Gizem; Kirdar, Didem; Kale, Meric; Altinkaya, Zeynep; Aktas, Dogukan; https://orcid.org/0000-0001-9274-7467; AGE-3003-2022
    This paper presents performance improvement studies performed in manufacturing activities of an aerospace company. Cellular Manufacturing (CM) and simulation approaches are used to improve performance in the factory of the company. In the application of CM, reorganization of machines in the machining section as manufacturing cells is performed by using Rank Order Clustering (ROC) algorithm and Hollier method. The performance improvement provided by CM application is measured in terms of the total material handling distances travelled by the parts. On the other hand, a simulation model in SIMAN is developed for panel production section of the factory. Based on the performance outputs of the simulation model, various recommendations are proposed in the operation rules and numbers of resources in the panel production section. The results show that both approaches provide considerable performance improvement in the manufacturing activities of the factory.
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    Building a Graphical User Interface for Concrete Production Processes: A Combined Application of Statistical Process Control and Design of Experiment
    (2019) Simsek, Baris; Pakdil, Fatma; Ic, Yusuf Tansel; Guvenc, Ali Bilge; AGQ-5008-2022
    Quality improvement and control in the manufacturing industry is a necessity for responding timely to increase customer needs and sustainability expectations. In order to decrease the variance in design and production functions, graphical user interface was built in this study implementing a combined methodology based on multi-response design of experiment and statistical process control. Graphical user interface based on MATLAB (R) toolbox allows analyzing the sufficiency of measurement system, calculating the capability of concrete production process, optimizing the manufacturing process via TOPSIS-based Taguchi design methodology and comparing the improvement rate of the process capability indices based on current and optimum conditions. After the Gauge R&R analysis, the current system process capability was considered for the C30/37 class (C30) normal weight concrete through process capability indices. In optimal system, process capability ratios, which are the degrees of compliance with the specifications of C30, were determined on the basis of TOPSIS-based Taguchi optimization. Eventually, the actual capability improvement provided through the proposed methodology was considered quite significant.
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    Optimisation of Cutting Parameters for Minimizing Carbon Emission and Maximising Cutting Quality in Turning Process
    (2018) Ic, Yusuf Tansel; Guler, Ebru Saraloglu; Cabbaroglu, Ceren; Yuksel, Ezgi Dilan; Saglam, Huri Maide; https://orcid.org/0000-0002-3732-1268; AAD-1956-2020
    Modern manufacturing systems are faced with the challenge of reducing the carbon emission related to manufacturing technologies. Machining centres consume large amounts of energy and as a consequence; carbon emissions are generated owing to this consumption. This paper presents a design of experiment work related to the optimisation of machining factors in the turning process of aluminium alloys. Carbon emission and surface quality were concurrently optimised. A set of experimental scenarios was set using a Box-Behnken design and the response surface methodology was applied to get the regression model for the carbon emission and surface roughness during turning process. The relationship between factors and the responses (carbon emission and surface quality) was investigated using surface plots. Furthermore, the desirability function method using the Response Optimizer tool in MINITAB and goal programming methodology was used to obtain the values of the parameters that achieved minimum surface roughness and a minimum quantity of carbon emission.
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    Improvement of the Surface Quality in the Honing Process Using Taguchi Method
    (2016) Yurdakul, Mustafa; Gunes, Serkan; Ic, Yusuf Tansel; 0000-0001-9274-7467; 0000-0002-1562-5738; AGQ-5008-2022; AAA-6966-2021
    Steel cylinders are critical components of hydraulic systems and they are available in various diameters and thicknesses. Defects and discontinuities that remain on the inner body surfaces of the cylinders after turning operation can harm components that move inside the cylinders such as pistons and piston seals. Honing operation is commonly performed after turning operation as a finishing operation to improve inner surface quality of cylinders. Honing operation reduces surface roughness values to acceptable levels. The most critical parameters that are important in the honing operation are honing tool head forward speed, rotational speed of the tool and honing stone grain size. Optimizing these parameters will increase honing operation productivity and provide the best surface roughness values. This study aims to obtain the values of the most critical parameters that provide the best surface quality in the honing operation using Taguchi method.
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    Development of a Computer Application for Multi-Response Taguchi Optimization
    (2016) Ic, Yusuf Tansel; Duran, Hikmet; Kececi, Baris; Ilik, Emrecan; Bilgic, Berkan; 0000-0001-9274-7467; 0000-0002-2730-5993; AGE-3003-2022; F-1639-2011; AAI-1081-2020; AAC-4793-2019; AGQ-5008-2022
    In this study, a computer application has been developed for the parameter optimization problem having maximum three quality characteristics and three parameters having three levels for each parameter. When the quality characteristics and the level of the parameters affecting the problem are obtained, appropriate Taguchi array in accordance with an appropriate experimental design is determined by using the developed application. After the collection of the experimental results for the quality characteristics, multi-response optimization problem is converted to single response problem by using the TOPSIS method. In the developed application any parameter design problems having single, two or three quality characteristic can be optimized.