Mühendislik Fakültesi / Faculty of Engineering
Permanent URI for this collectionhttps://hdl.handle.net/11727/1401
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Item Six Sigma Project Prioritization and Selection Using AHP-CODAS Integration: A Case Study in Healthcare Industry(2023) Can, Gulin Feryal; Toktas, Pelin; Pakdil, Fatma; https://orcid.org/0000-0001-6622-4646; D-7271-2018Given the complex nature of Six Sigma project (SSP) prioritization and selection processes, multicriteria decision-making (MCDM) methods may help organizations identify the most effective projects. Considering potential limitations of subjective methods and advantages of MCDM methods, this article proposes a model that integrates analytical hierarchy process (AHP) and combinative distance-based assessment (CODAS) in SSP prioritization and selection process. In the proposed approach, AHP is employed to assign criteria weights, and CODAS is performed to determine priorities of SSPs. CODAS was advanced in term of its threshold function. Differences between Euclidean distances of two alternatives were compared, based on the standard deviation of Euclidean distances of all alternatives to overcome the subjectivity. This is the first study that combines AHP and CODAS methods for SSP selection, and CODAS is used with objective threshold value computation, and developed for the healthcare industry. In this article, ten SSPs were evaluated for four key criteria groups as financial, operational, patient centric, and organizational main criteria groups. In total, 18 subcriteria were considered under these four main criteria groups. This article provides a support for executives who make implementation plans for the potential SSPs.Item Working Posture Analysis in Fuzzy Environment and Ergonomic Work Station Design Recommendations(2015) Can, Gulin Feryal; Atalay, Kumru Didem; Eraslan, Ergun; 0000-0002-5667-0391; AAE-7165-2019Realization of ergonomic design applications in working environments, makes it possible to preserve the health of employees, provide them working comfort and increase productivity. Therefore ergonomic work station design has an outstanding position in work places. In this study, an investigation was made on work stations in a metal accessor producer, which were found to be inappropriate from point of view of design considerations as a result of an ergonomic condition analysis. Inappropriate designs force workers to repetitively assume dangerous postures. As a result production process slows down and workers experience a feeling of increasing tiredness. Postures of workers were analyzed by The Fuzzy Rapid Entire Body Assessment (BREBA) developed by inserting triangular fuzzy scale to Rapid Entire Body Assessment (REBA). The BREBA method determines the level of risk in whole body caused by postures while prevents potential information loss and allows obtaining more accurate results in a fuzzy environment. In the said working place, 688 posture photographs belonging to four work stations (heat treatment, primary press, secondary press and transportation station) were examined. The consequent assessment suggested that; leg, upper arm and wrist in heat treatment, leg, wrist and torso in pres station, torso and arm were found to be the most enforced body sections. The results pointed out that 52,03% of postures displayed in production process introduced medium level risk and improvements were suggested.Item A New Hybrid Intuitionistic Approach for New Product Selection(2018) Atalay, Kumru Didem; Can, Gulin FeryalThis paper proposes a new hybrid approach for multi-criteria decision-making problems combining intuitionistic fuzzy analytic hierarchy process and intuitionistic fuzzy multi-objective optimization by ratio analysis. Analytic hierarchy process has an inherent ability for handling intangible problems and implements a simple scale to represent evaluations in the structure of pairwise comparisons. Multi-objective optimization by ratio analysis optimizes the solution of a problem having two or more conflicting objectives, taking into account certain constraints. In real-life decision problems, evaluations of decision makers related to performance of alternatives and criteria weights can be expressed by linguistic terms comprising vagueness and uncertainty. These uncertain, vague and hesitant judgments of decision makers can be described more comprehensively by using intuitionistic fuzzy set theory. The proposed approach is a powerful tool for dealing with information which consists of hesitancy and vagueness. An illustrative example related to new product selection for a company is also presented to demonstrate the implementation of the approach.Item A Case Study on Shopping Malls Attributes for Young Consumers(2016) Can, Gulin Feryal; Kurtulmusoglu, Feride Bahar; Atalay, Kumru DidemPurpose - This study aims to determine the mall criteria that are the most crucial for the youth market by determining the winning brand in comparison to other offerings to understand what is required to gain a competitive advantage and to differentiate a mall from its rivals. Design/methodology/approach - This study chose the Stochastic Multicriteria Acceptability Analysis-2 method to evaluate the mall preferences of young people. By using this method, the various criteria were evaluated for more than one alternative to find the best solution. JSMA program was used to analyze the data. The survey was administered using the mall intercept method to reduce sample bias. Findings - The study identifies that the criteria that have the highest impact on the mall preferences of young people are the mall campaigns for loyal customers; the traffic in the mall locality and the mall's parking facilities; the mall's facilities for disabled people; the quality of the mall locality; and the quality of the people visiting the mall. The study reveals that a mall's physical features, its facilities and the criteria related to employees have a very low impact on the mall choices of young people. The study further finds that the youth market has very low satisfaction levels for all of the identified criteria. This study reveals that this macro accessibility criterion is less relevant for the youth market than for the general population. Originality/value - Despite the importance of this market, there is insufficient research on the shopping behavior of young people. They have a considerable impact on the purchasing decisions of their families, significant disposable income and constitute the future market for the sector. This study uniquely enables the sequential ordering of customers' decision-making criteria and determines the effectiveness or impact of these criteria in the mall sector.Item A Stochastic Approach for Failure Mode and Effect Analysis(2017) Delice, Elif Kilic; Can, Gulin FeryalThis study presents a novel approach combining Failure Mode and Effect Analysis (FMEA) and Multi-Attributive Border Approximation Area Comparison (MABAC) method based on a stochastic evaluation process to prioritize potential failure modes (FMs) in an assembly line. The aim of the proposed approach is to improve the performance of FMEA by eliminating its shortcomings addressed in the study. In this context, firstly the risk factor (RF) importance weights and the performance values of the FMs for the RFs are determined by generating random numbers having uniform distribution in a range of minimum and maximum value of a limited number of expert evaluations. In this wise, the number of experts are increased to improve effectiveness of the risk evaluation process. Diverse opinions of experts are also assessed more precisely. Secondly, the priorities of the FMs are identified by implementing MABAC method. MABAC is a practical and reliable tool which provides stability for solutions. Finally, a comparative analysis is implemented to confirm the effectiveness of Stochastic FMEA-MABAC approach.Item A New Stochastic MCDM Approach Based on COPRAS(2018) Ayrim, Yelda; Atalay, Kumru Didem; Can, Gulin FeryalThis study proposes a novel integrated Complex Proportional Assessment (COPRAS) approach by using stochastic decision process named as Stochastic COPRAS (COPRAS-S) to increase the evaluation performance of COPRAS. In COPRAS-S, criteria importance weights and the performance values of alternatives are determined by generating random numbers from uniform distribution in a range of minimum and maximum values of a limited number of decision-maker evaluations. Thus, the numbers of experts are increased and decision-making process is performed in an effective way because different opinions are incorporated. In addition, randomness feature brought with vagueness in decision is modeled in this process. A special normalization approach based on standard deviation is also implemented in COPRAS-S. In this way, cost and benefit type criteria are evaluated in a different way. This proposed stochastic structure for COPRAS is a practical and powerful tool that strengthens the decision.Item An Intutionistic Approach Based On Failure Mode and Effect Analysis for Prioritizing Corrective and Preventive Strategies(2018) Can, Gulin FeryalAlthough Failure Mode and Effect Analysis (FMEA) is a prominent approach that has been used with convenience as the most popular risk definition and evaluation tool related to a system, a product, or a service, it has several deficiencies. This study addresses these deficiencies and proposes a new intuitionistic approach, which combines FMEA and Weighted Aggregated Sum Product Assessment (WASPAS) by implementing a new intuitionistic scale. Intuitionistic FMEA-WASPAS can handle uncertainty, vagueness, and hesitancy of the risk evaluation process and provides flexibility for risk assessment. In this study, rankings of corrective-preventive strategies for failure modes (FMs) are obtained by the proposed approach. To compute Intuitionistic Fuzzy Risk Priority Numbers, occurrence, severity, detection, cost, duration of exposure, and system safety factors are used. A numerical example is also illustrated to present the practicality and effectiveness of the Intuitionistic FMEA-WASPAS approach.Item Does Gender Matter? Considering Gender of Service in the Airline Industry(2018) Kurtulmusoglu, Feride Bahar; Can, Gulin Feryal; Pakdil, Fatma; Tolon, MetehanAirline firms prioritize service features on the basis of customers' demand. While prioritizing these service features, successful positioning strategies are expected to focus on gender specific concerns. Given the fact that previous literature relies heavily on gender neutral strategies in airline industry, this study particularly addresses critical service features prioritized by female and male passengers by ranking airlines based on a multi-criteria decision-making method. Comfortable chair, seat space and leg room, and flexibility in reservation change were discovered as the three most impactful service features for female passengers. Availability of non-stop flight, frequency of flights, and airfare appeared as the other three most impactful service features among male passengers.Item A Task-Based Fuzzy Integrated MCDM Approach for Shopping Mall Selection Considering Universal Design Criteria(2018) Can, Gulin Feryal; Delice, Elif Kilic; 0000-0002-3051-0496Shopping malls (SMs) are one of the prides of cities with their attractive appearance, charming stores and different consumer types. The heavy competition, ever increasing and diversifying consumer expectations alongside the changes in the demand equilibrium in the mall sector force managers to a really hard struggle to remain alive in the sector. This study aims to resolve the decision-making problem of SM selection by considering several different main criteria such as universal design, technical characteristics, esthetic appearance etc. The method used to resolve this problem is a task-based integrated fuzzy multi-criteria decision-making (TB-IFMCDM) approach that includes Modified Fuzzy Decision-Making Trial and Evaluation Laboratory (MF-DEMATEL) and Fuzzy Multi-Objective Optimization on the Basis of Ratio Analysis (F-MOORA). It also aims to determine the best SM through the support of universal design criteria by simultaneously considering the needs of all consumers including those of diverse populations, which is a rapidly growing market. As such, SM-selection-related tasks are given to experts who are treated like and act as consumers. Criteria weights are computed considering direct and indirect effect relations by transforming criteria importance to criteria effect, via utilization of MF-DEMATEL. Additionally, rankings of four SMs are obtained by implementing F-MOORA. Finally, a comparative analysis is conducted to determine the consistency of the ranking of the proposed approach by comparing them with the results of the fuzzy complex proportional assessment. As a result of this study, it is identified that design-related criteria are most important for SM selection.Item A Novel Multi-Criteria Decision-Making Approach Proposal Based on Kemira-M with Four Criteria Groups(2022) Ay, Sefacan; Can, Gulin Feryal; Toktas, PelinThis study aims to eliminate the subjectivity in the weight assignment process of Modified Kemeny Median Indicator Ranks Accordance (KEMIRA-M) and to remove the need for experts to reach a consensus on determining the criteria weights. Additionally, this study aims to apply KEMIRA-M for four different criteria groups and to prevent some criteria from taking a weight value of "0", as in other studies using KEMIRA-M. In this context, the weighting procedure of KEMIRA-M is advanced using three different ranking-based weighting methods such as Rank Sum (RS), Rank Exponent (RE) and Rank Reciprocal (RR) to operate Median Priority Components (MPCs) more effectively. Accordingly, to determine which weighting method for which criterion group is more suitable, the selection procedure of KEMIRA-M was applied and alternative rankings were obtained for 81 different weight set combinations. Additionally, MATLAB codes have been used to provide flexibility for the application of the proposed approach in a supplier selection problem selected for a case study.