YÖK Akademik
Permanent URI for this collectionhttps://acikarsiv.thk.edu.tr/handle/123456789/2553
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Publication Development of a Restraint System for Rear-Facing Car Seats(Machines, 2023-01-01) Himmetoğlu, Selçuk; Yavuz, SametIn self-driving vehicles, passengers can set their seats in an unconventional seating position, such as rear-facing. Sitting in such an orientation can increase the risk of whiplash in the head-and-neck system in a frontal impact, as frontal crashes usually have higher severities compared with rear-end crashes. This paper shows that a forward-facing front seat optimised for rear-impact protection needs to be redesigned to be used as a rear-facing seat. In the second and main part of this paper, a restraint system for rear-facing car seats is developed, and frontal impact simulations with 64 km/h of delta-V are used to evaluate its performance. The designed seating system comprises two rigid torso plates, a fixed recliner and an energy absorber under the seat pan. Without using the developed restraint system, the 50th percentile male human model is exposed to neck shear forces exceeding 600 N. With the developed restraint system, neck shear forces are less than 350 N in frontal impacts with 64 km/h of delta-V. Apart from whiplash, the risk of head, chest, lower extremity and lower back injuries are also evaluated. The results confirm that the developed restraint system successfully protects the occupant since all assessment criteria values are lower than the injury assessment reference values.Publication Çok Amaçlı Tedarik Zinciri Optimizasyon Modelleri için Kapsamlı bir Literatür Araştırması(2023-01-01) güven; Güner, Gürkan GüvenPublication Sürdürülebilir Sağlık Yönetimi Optimizasyonu Kapsamlı Bir Literatür Araştırması(2023-01-01) Güner, Gürkan GüvenPublication Düzensiz Operasyon Yönetimi için Entegre Havayolu Çizelgeleme Yaklaşımı Karışık Tam Sayılı Doğrusal Olmayan Programlama ve Tavlama Benzetimi(2024-01-01) S. Erol; Güner, Gürkan GüvenPublication A Multi-Criteria Solution Approach for the Alternative Preventive Maintenance Applications in the Aviation Industry(2022-01-01) B. Gever Ekinci; Güner, Gürkan Güven; C. BalıkçıFor the aircrafts to continue their operations actively, implementing systematic maintenance to the aircrafts are required by the aircraft manufacturers and civil aviation authorities. These operations are carried out by the aircraft operating companies as a priority. How often and at what levels the maintenance will be applied is specified in the maintenance manual published by the manufacturers. The maintenance to be performed varies depending on the mission feature of the aircraft, the flight time, or a certain calendar period. The aviation administration periodically classifies the maintenance concepts to be applied according to the frequency of maintenance by taking advantage of the maintenance criteria determined in the maintenance manual. In this classification, the maintenance operations are arranged based on "preventive maintenance" for the aircrafts to continue their activities effectively. The applied maintenance concepts are determined in the military and civilian sectors in accordance with the intended use of aircraft. In this study, in terms of the criteria determined by the application of Multi-Criteria Decision-Making methods in the literature, the most critical aircraft parts for the alternative preventive maintenance applications were identified with the real data of the Cessna 172 Skyhawk training aircrafts. After determining the criterion weights with AHP (Analytical Hierarchy Process) method, the most critical aircraft parts were prioritized with the AHPweighted TOPSIS (Technique for Order of Preference by Similarity to Ideal Solution) method. The criteria considered in the study are the unit cost, the lead time, and the total number of failures in a year of the aircraft part. Then, the reliability analyses are performed to suggest an alternative age-based preventive maintenance policy. In accordance with this purpose, real failure data are analyzed to find failure probability distributions, mean times between replacements, and cost efficiency values of each critical part. As a result, an alternative preventive maintenance policy is suggested for each critical aircraft part by determining the optimal maintenance intervals where the preventive maintenance is cost-effective. The proposed study is intended to provide guidance for alternative preventive maintenance practices in the airline industry.Publication Latest Heuristic Solution Approaches for the Analog Circuit Design Optimization A Literature Review(2022-01-01) Güner, Gürkan Güven; G. Demirci; B. AltunoğluThere are many studies, which propose different heuristic and metaheuristic solution approaches for analog circuit design optimization, in the literature. Analog circuits have great design complexity in terms of circuit parameters, and each of the analog circuit designs has different limitations because of the various requirements. In general, analog circuit design steps are composed of choosing circuit structure, then optimizing the circuit parameters. Circuit parameters need to be designed for the output of the circuit such as power, noise, and gain. Due to the complexity and time-consuming factors for the circuit design, innovative and scientific solution approaches become important for the analog circuit design solution. This study focuses on the latest heuristic and metaheuristic solution approaches, such as the evolutionary algorithms including genetic algorithm and particle swarm optimization, for the analog circuit design considering different single-objective and multi-objective problems to show the future trends about the solution methodologies. The latest studies in the literature are classified according to their purposes, solution methodologies, and considered problems. It is intended that the comprehensive literature review in this study will be helpful for the decision-makers about suggesting a course of action for the latest trends in the optimal design of the analog circuits.Publication Publication A Literature Review on Master Production Scheduling Problems in the Automotive Industry(2023-01-01) Güner, Gürkan GüvenIn recent years, production by customer has been adapted to a very large number of industries. One of them is the automotive industry. The aim is to ensure low unit cost mass production processes and fulfill each production requirement. Production according to customer request requires flexible manufacturing equipment. In addition, this production requires a versatile (multi-tasking) and highly equipped workforce. In the automotive industry, the arrangement of end products according to customer specification requires considering a large number of optional (non-mandatory) parts. This results in a great variety of processing times at different stations of the assembly line. Multivariate and mixed-model production assembly lines in the automotive industry require five key planning problems to be considered. These; line balancing, master production scheduling, production sequencing, material flow control, and reordering. The master production scheduling problem for multivariate and mixed-model assembly lines is aimed at assigning each variant of a basic product type to production periods, depending on customer preferences. This problem requires anticipating the negative effects of an unbalanced model sequence at a low planning level (in the early stages of the planning process) and acting accordingly. This study deals with the master production scheduling problems applied in the automotive industry and provides a comprehensive literature search on the topic touched on by a limited number of studies. In addition, the dependency between master production scheduling and production sequencing and heuristic solution approaches were analyzed in detail in the study. The presented literature search is intended to serve as a guide for decision makers for the master production scheduling problems considered in the automotive industry.Publication A Comprehensive Literature Survey on Logistics Strategy and Supply Chain Optimization in the Biomass Energy Sector(2023-01-01) Güner, Gürkan GüvenPublication Literature Review on Sustainable Renewable Energy Supply Chain Optimization A Focus on Heuristic and Metaheuristic Methods(2023-01-01) Güner, Gürkan GüvenThe transition towards sustainable energy systems has necessitated the optimization of renewable energy supply chains. This literature review aims to explore the state-of-the-art approaches, with a specific focus on heuristic and metaheuristic methods, employed for optimizing sustainable renewable energy supply chains. Metaheuristics, which are higher-level strategies for guiding search processes, have demonstrated great potential in tackling complex optimization problems with diverse constraints and objectives. Genetic algorithms, simulated annealing, ant colony optimization and particle swarm optimization are some of the examples for the metaheuristic methods. The review emphasizes their ability to provide near-optimal solutions, handle uncertainties, and optimize multiple conflicting objectives. This literature review synthesizes and analyzes the existing research on heuristic and metaheuristic methods for optimizing sustainable renewable energy supply chains.