Scopus İndeksli Açık & Kapalı Erişimli Yayınlar

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Author: search.filters.author.Ic, Yusuf TanselHas files: No

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    The Use of Petri Nets in Performance Analysis of Flexible Manufacturing Cell
    (2022) Bulca, Fatima Busra; Ic, Yusuf Tansel; Yurdakul, Mustafa
    A Flexible Manufacturing Cell (FMC) is a system that consists of computer-integrated machines, automatic material handling systems, and robots. It produces different part types with minimal worker involvement. Many different methods, such as queuing systems and simulation models, have been applied in FMC modeling in the literature. This study aims to use Petri Nets (PN) in modelling complex FMCs. The study is carried out in the FMC located in the Advanced Manufacturing Systems Laboratory of Baskent University. The FMC consists of a CNC machining center, a material handling robot and a pallet, which has three work-piece carriage capacities. Processing times of FMC elements may vary due to reasons (the power usage performance, air supply efficiency, electrical power efficiency, etc.) arising from the mechanical structure of the system. This uncertainty needs to be taken into account when modeling the system. In this study, the uncertain (fuzzy) processing times associated with the transitions were caused by the mechanical structure of the system. In order to compare with the newly developed fuzzy models, the system was first modeled using Transition Time Petri Nets (TTPN), in which the running times associated with the transition times take precise values. On the other hand, for handling fuzzy values of the actual operating times in the FMC, two models namely, Partial-Fuzzy Transition Time Petri Nets (Partial-FTTPN) and Fuzzy Transition Time Petri Nets (FTTPN) are developed. The results of the three models are compared to analyze the benefits of combining "time uncertainties" resulting from the natural behavior of FMCs.
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    A Forecasting Study for Renewable Energy Resources Investments in Turkey: TOPSIS-Based Linear Programming Model
    (2023) Oluklu, Dicle; Ic, Yusuf Tansel; 0000-0001-9274-7467
    In this paper, a Technique for Order Preference by Similarity to Ideal Solution (TOPSIS)-based linear programming (LP) approach is developed for determining optimal quantities of renewable energy sources according to the source's potential compared with other renewable energy alternatives. A combined model is established with the forecasting model, TOPSIS, and LP methods to determine optimal results. The developed decision support approach's applicability is illustrated in this paper. The paper illustrates how renewable energy sources can be preferred to meet additional energy demand in the next five years in Turkey using the developed TOPSIS integrated LP model. For this objective, a time series analysis is applied to estimate production capacity for the constraints of the mathematical model. Then, a question is answered how much energy should be produced from which alternative for each year? A flexible structured mathematical model is developed to meet the necessary energy requirements in dynamic and variable economic systems. So, the decision-maker can assign different criteria weights in the TOPSIS model, which is integrated with LP, and obtain new optimal solutions related to requirements in the future.
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    Analysis of the Robustness of the Operational Performance Using a Combined Model of the Design of Experiment and Goal Programming Approaches for a Flexible Manufacturing Cell
    (2023) Ic, Yusuf Tansel; Yurdakul, Mustafa; Dengiz, Berna; Sasmaz, Turgut
    A combined model of a 2(k) design of experiment (DOE) and goal programming (GP) approaches is presented to determine optimum levels of input variables and analyze their robustness for a multiobjective performance of a flexible manufacturing cell (FMC) in this study. Two main performance metrics, namely, manufacturing lead time (MLT) and surface roughness (SR), are considered performance outputs for the FMC. Machine sequence, robot speed, tool type, and material type are selected as the four input variables on the input side of the proposed model. The study shows that even with a limited number of experiments, one can determine optimum input levels for the multiobjective performance of the FMC and determine their robustness.
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    Development of a Goal Programming Model Based on Response Surface and Analytic Hierarchy Process Approaches for Laser Cutting Process Optimization of St-52 Steel Plates
    (2022) Yurdakul, Mustafa; Tukel, Taha; Ic, Yusuf Tansel
    This paper presents an integrated model for optimization of laser cutting process of St-52 steel plates with multiple performance characteristics using Goal Programming (GP), Analytic Hierarchy Process (AHP), and Response Surface Methodology (RSM) approaches. In this study, optimum levels of the laser cutting process input parameters namely, material thickness, cutting speed, laser power, and assist gas pressure are obtained. For optimization purposes, four different surface roughness types of a cut surface, surface hardness, cutting time, and heat-affected zone (HAZ) of the cut surface are considered as performance outputs (responses) in this study. Optimization of multiple performance objectives (responses) requires obtaining regression functions with RSM first, and then weighting the regression functions using the AHP and finally combining the multiple functions into a single overall goal within a GP model and solving the model to optimize the laser cutting process. The study clearly shows that the presented optimization model is flexible enough to optimize the laser cutting process for various scenarios and conflicting priorities.
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    A Simplified Throughput Model for a Unit-Load AS/RS Considering Dynamics Principles
    (2022) Ic, Yusuf Tansel
    This paper presents a unit-load automated storage and retrieval system's (AS/RS) throughput analysis that uses an S/R machine for diagonal aisle transportation and a structure for both vertical and horizontal transportations. Although many methods are available to compute the AS/RS throughput rate, the method recommended by the Material Handling Institute (MHI) is more suitable for real or practical cases. This method assumes (i) randomized storage with constant vertical and horizontal speeds of the S/R machine, and (ii) simultaneous travel in both directions. We consider a new simplified and more efficient approach for MHI's method to predict the throughput performance of the AS/RS.
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    A Multi-Objective Mathematical Model for Level of Repair Analysis with Lead Times and Multi-Transportation Modes
    (2022) Bicakci, Ismail; Ic, Yusuf Tansel; Karasakal, Esra; Dengiz, Berna; https://orcid.org/0000-0001-9274-7467; AGE-3003-2022
    In the event of failure of the product, level of repair analysis (LORA) is used to determine (1) whether the defective component should be discarded or repaired and (2) where this repair is made. In the literature, these repair operations are made with the aim of minimizing the total life cycle cost of the product. In this paper, we develop a multi-objective decision model that minimizes both the repair time (affected by lead times) and the repair costs. Our proposed model also considers the movement of the defective components to be performed by multiple transportation modes such as highway, railway, and airway. We use the epsilon constraint method to generate the Pareto frontier and analyze the trade-off between total repair costs and total repair time. We demonstrate the approach on an example problem.
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    Analysis of the manufacturing flexibility parameters with effective performance metrics: a new interactive approach based on modified TOPSIS-Taguchi method
    (2022) Ic, Yusuf Tansel; Sasmaz, Turgut; Yurdakul, Mustafa; Dengiz, Berna; 0000-0001-9274-7467; AGE-3003-2022
    Flexibility is one of the most important strategy parameters to achieve a long-term successful performance for a manufacturing company. Studies in the literature aim to operate a manufacturing system at optimum levels of flexibility parameters under its own manufacturing environment. This study aims to present an interactive analysis framework based on TOPSIS and Taguchi parameter design principles for investigating the effects of different levels of flexibility parameters on the performance of a flexible manufacturing cell (FMC). The main performance metric used in this study is manufacturing lead time. Other important metrics to evaluate quality control and inspection policies are also investigated in this study. To conclude, a combined model of an interactive approach based on TOPSIS and Taguchi methods are used to assess the effectiveness of the flexibility parameters for a FMC.
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    Development and comparison of airplane fuselage panel assembly system alternatives using axiomatic design principles and simulation methodology
    (2022) Celek, Osman Emre; Yurdakul, Mustafa; Ic, Yusuf Tansel; 0000-0001-9274-7467; AGE-3003-2022
    This paper presents a combined usage of axiomatic design principles and simulation in developing and comparison of alternative assembly systems for airplane fuselage panels. In the application, four assembly system alternatives are obtained with axiomatic design methodology; and their performance results are obtained using simulation. The simulation results are made available for system designers to see each alternative's capabilities and make a comparison among the alternatives. The application of the proposed combined application of axiomatic design principles and simulation provides a reference guide for system designers to apply in designing other assembly systems' design.
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    Risk-based inspection planning for internal surface defected oil pipelines exposed to fatigue
    (2022) Sozen, Levent; Yurdakul, Mustafa; Ic, Yusuf Tansel
    The pipelines should be inspected periodically to minimize the probability of failure. The timing of these periodic inspections can be determined by a risk assessment that considers the probability of failure of the pipeline and the potential undesirable effects of the chemical transferred. These are referred to as risk-based inspection methods in the literature. We evaluate pipelines with internal surface defects and under the effect of variable pressure in this study. Internal surface defects were considered production-related, and there is a lack of studies in the literature examining such kinds of defects. These defects generate the concentration of stress on the pipeline section. The reliability variation of the pipeline depends on some factors, namely, surface defect ge-ometry, the pipe section geometry, and the mechanical properties of the pipe. Fatigue is accepted as the crucial damage mechanism. The cause of variable load is considered as the number of operations. As a result of the study, the probability of fatigue failure for pipelines with internal surface defects was evaluated. Then, a new approach was proposed for risk-based inspection planning of the pipelines. As a case study, the probability of fatigue failure on a fuel pipeline established between a refinery and an oil terminal operating in Turkey was calculated. Also, we tried to determine the most appropriate inspection time. The data used in the planning phase was collected from a measurement process performed on the pipeline using PIG (Pipe Inspection Gauge). Finite element analysis was used to calculate stress concentration factors. Finally, we used the Monte Carlo simulation method to obtain the probability of failure.
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    Variable refrigerant flow air conditioning system applicant company selection using PROMETHEE method
    (2022) Abaci, Nejla; Ic, Yusuf Tansel; https://orcid.org/0000-0001-9274-7467; AGE-3003-2022
    Variable refrigerant flow (VRF) air conditioning systems have become highly preferred in the air conditioning sector has enabled many new companies to enter the industries of VRF Air Conditioning Systems manufacturer and applicant. It has become difficult for decision-makers to select the best applicant company among the alternatives. In this article, the applicant company selection model is developed for heat-pump VRF air condition systems to meet the heating and cooling needs of buildings. The operation and structure of the VRF systems and their selection criteria are determined for the applicant company. Using the Preference Ranking Organization METHod for Enrichment of Evaluations (PROMETHEE) method, one of the multi-criteria decision-making methods, an application company selection model has been presented for three different buildings according to the building characteristics and climate conditions.