Mühendislik ve Doğa Bilimleri Fakültesi Koleksiyonu

Permanent URI for this collectionhttps://hdl.handle.net/20.500.13091/1624

Browse

Now showing 1 - 20 of 91

Citation - Scopus: 5
Achieving Shojinka by Integrated Balancing of Multiple Straight Lines With Resource Dependent Task Times
(Springer New York LLC, 2019) Atasagun, Y.; Kara, Y.; Can Atasagun, Gözde
The concept of Shojinka, which is an important element of Just in Time production system, is attaining flexibility on the number of workers in a workshop due to demand variations. Even though Just in Time production system adopts U-shaped line layout, traditional straight lines can be combined and balanced in an integrated manner to obtain the advantages of Shojinka. In this case, the problem, which is called Integrated Balancing of Multiple Straight Lines, arises. On the other hand, the basic assumption of assembly line balancing is that every task’s time is fixed. However, in practice, different resource alternatives such as equipment or assistant worker may be available to process a task with different times. The problem in this case is to assign tasks and resources to stations that minimise total cost. In this study, a binary integer mathematical model is presented for integrated balancing of multiple straight lines, assuming that task times are resource dependent. The proposed model is illustrated and validated using several examples. An experimental analysis is also conducted to emphasize the advantages of the integrated balancing concept, compared to the situation in which the lines are balanced independent from each other. The experimental results show that, when multiple straight assembly lines are balanced in an integrated manner with resource dependent task times, an average total cost improvement of 23.105% can be obtained compared to the independent balances of the lines. This is a significant improvement that emphasizes the importance of balancing multiple straight lines in an integrated manner, to take the advantages of shojinka and to adhere to the main philosophy of Just in Time. © Springer Nature Switzerland AG 2019.
Citation - Scopus: 4
Analysis of the Studies Done on Laboratories in Turkey
(Ekip Buro Makineleri A., 2020) Yener, Dündar; Köklü, Niğmet; Yamaç, Ramazan Ziya; Yalçın, Seher
The aim of this study is to determine the trend of studies in the laboratory and put the current situation in Turkey. For this purpose, document analysis technique, one of the qualitative research methods, was used in the research. The data group of the research consists of thesis studies on laboratories in our country between 1999-2017. Theses in the fields of science, physics, chemistry, and biology have been determined and themes and sub-themes have been created through the keywords of these theses. Then, frequency tables were created according to the themes and sub-themes created. According to the findings obtained, it was seen that the traditional laboratory approach and inquiry-based laboratory approaches are compared in the studies. It was determined that the studies were done on physics subjects and it was determined that complementary measurement and evaluation studies performed for performance evaluation were used in very few numbers. In addition, it was concluded that the keywords did not give enough information about the studies. In this context, it can be suggested to examine the effectiveness of these approaches according to each other and experiment types by examining the approaches in which students can be more active in laboratories. © 2020. All Rights Reserved.
Citation - Scopus: 4
An Application of Fuzzy Ahp, Edas and Waspas for the Selection of Process Method in Software Projects
(Springer Science and Business Media Deutschland GmbH, 2022) Yel, İ.; Sarucan, Ahmet; Baysal, M.E.
In software development projects, the complexity of the tasks to be completed and the fact that the resources are real people, unlike in the manufacturing sector, are important factors that pose challenges to project management. In addition, operational reasons such as time-dependent changes in software requirements also complicate the management of projects. During the execution of the projects, in addition to the internal dynamics of the project, the organizational characteristics of the participants and the competencies of the team also influence the success of the project. In this context, various software development process methodologies are used for change management, including “Agile and Waterfall Methods”. The aim is to select projects based on technical and managerial criteria by considering the skills of the development teams that actively participate in the project. In the study, the weights of the criteria are determined using fuzzy AHP. Then, Fuzzy EDAS and WASPAS methods are used for ranking the projects and the information technology teams. The statistical information about the errors after software development was obtained as a result of the process management decision made. © 2022, The Author(s), under exclusive license to Springer Nature Switzerland AG.
Aralık Tip-2 Bulanık Kural Tabanlı Ahp Yaklaşımı İle Tedarikçi Seçimi
(2019) Paksoy, Turan; Öztürk, Müslüm
Kriterlerin ve alternatiflerin çok ve belirsizliğin yoğun olduğu problemlerin çözümünde klasik mantık kümelerine göre, tip-2 bulanık mantık kümeleri kullanılır. Çünkü daha esnek ve başarılıdırlar. Bu nedenle, Çok Kriterli Karar Verme problemlerinin aralık tip-2 bulanık sayılar ile entegre edilmesi karar verme sürecinde avantajlar sağlayacaktır. Öte yandan, karar vericinin etki derecesini yansıtmak için insan duyarlılığının kullanılmasını gerektiren karar verme sürecinin karma bir analizi bulanık kural tabanı ile ifade edilebilir. Bu çalışmada, uzman görüşleri de dikkate alınarak uygun tedarikçi seçimi için üç kriter altında üç alternatifin sıralanması; öncelikle Kahraman ve ark. (2014) tarafından önerilen kural tabanı olmayan Aralık Tip-2 Bulanık Analitik Hiyerarşi Prosesi Yöntemi kullanılmış, daha sonra ise alternatiflerin sıralanması bu çalışma kapsamında önerilen Aralık Tip-2 Bulanık-Kural Tabanlı Analitik Hiyerarşi Prosesi ile yapılmıştır. İki yöntem sonucunda elde edilen sıralama sonuçları üzerinde Kendall Tau Korelasyonuna dayalı Sıralama Performansı Değerlendirmesi işlemi yapılmış ve elde edilen sonuçlardan Aralık Tip-2 Bulanık- Kural Tabanlı Analitik Hiyerarşi Prosesi ile yapılan sıralama performansının daha yüksek olduğu görülmüştür. Ayrıca yapılan uygulama çalışması sonucunda, uygulanan Aralık Tip-2 Bulanık Analitik Hiyerarşi Prosesi Yönteminin, firmalar için tedarikçi seçiminde kullanılabileceği ortaya konulmuştur.
Citation - WoS: 24
Citation - Scopus: 23
Artificial Bee Colony Algorithm for Solving Multi-Objective Distributed Fuzzy Permutation Flow Shop Problem
(IOS Press BV, 2022) Baysal, Mehmet Emin; Sarucan, Ahmet; Büyüközkan, Kadir; Engin, Orhan
The distributed permutation flow shop scheduling (DPFSS) is a permutation flow shop scheduling problem including the multi-factory environment. The processing times of the jobs in a real life scheduling problem cannot be precisely know because of the human factor. In this study, the process times and due dates of the jobs are considered triangular and trapezoidal fuzzy numbers for DPFSS environment. An artificial bee colony (ABC) algorithm is developed to solve the multi-objective distributed fuzzy permutation flow shop (DFPFS) problem. First, the proposed ABC algorithm is calibrated with the well-known DPFSS instances in the literature. Then, the DPFSS instances are fuzzified and solved with the algorithm. According to the results, the proposed ABC algorithm performs well to solve the DFPFS problems. © 2022 - IOS Press. All rights reserved.
Balancing Disassembly Line Under Hazardous Parts With Precise and Fuzzy Goals
(2022) Hezer, Seda; Kara, Yakup
Disassembly is one of the steps of the recovery activities. Since it includes expensive processes, disassembly shoul be performed with the system that provides efficient and effective outputs. A disassembly line is the most suitable system for disassembly of the returned products. A disassembly line balancing problem (DLBP) is assigning disassembly tasks to consecutive workstations by satisfying a series of constraints and optimizing one or more than one goal. In this paper, the DLBP with multiple conflicting goals which takes into account the negative zone (DLBP-Z) constraints has been proposed. Negative zone constraint is related to hazardous parts. If there are hazardous part/parts in the product and they need to be removed, they may damage the othetr parts and disassembly line. Therefore, these parts must be assigned to different stations from the other parts. Goal programming (GP) and fuzzy goal programming (FGP) approaches have been proposed in order to optimize three conflicting goals, namely total net recovery profit value, the number of parts to be removed for recycling and cycle time. Through a numerical example, the proposed approaches have been tested and goal programming formulations have been shown to be valid and useful. To the best of the authors knowledge, the proposed GP and FGP models are the first multi citeria decision making (MCDM) approaches for DLBP-Z.
Beklemesiz Akış Tipi Çizelgeleme Problemlerinin Analizi ve Hibrit Dağınık Arama Yöntemi ile Çözümü
(2022) Başar, Ramazan; Engin, Orhan
Beklemesiz Akış Tipi Çizelgeleme (BATÇ), pratik uygulamalarından dolayı kapsamlı bir araştırma alanıdır. BATÇ problemlerinde işler, makinelerde kesintisiz olarak işlem görmek zorundadır. Bir işin tüm makinelerde işlenme süresi boyunca, makineler bekleyebilir fakat işler kesintisiz olarak işlenmelidir. Amaç ise makinelerin boşta bekleme süresini en aza indirmektir. BATÇ problemlerinin çoğunluğunda toplam gecikmenin ve maksimum tamamlanma zamanının minimizasyonu olmak üzere, iki performans ölçüsü göz önünde bulundurulur. Literatürde, son yirmi beş yılda BATÇ ile ilgili yapılan çalışmalar analiz edilmiştir. BATÇ problemlerinin çözümü ile ilgili geliştirilen kesin ve yaklaşık çözüm veren yöntemler incelenmiştir. Literatürde 1 ve 2 makineli problemler için optimum çözüm veren matematiksel yöntemler bulunurken, 3 ve daha fazla makineli problemler için standart zamanda optimum çözüm veren bir yöntem bulunmamaktadır. Kabul edilebilir bir süre içerisinde m makine içeren problemlere optimum ya da optimuma yakın çözümler üretebilmek için sezgisel ve meta sezgisel yöntemler geliştirilmektedir. Bu çalışmada, BATÇ problemlerinin çözümü için Hibrit Dağınık Arama (HDA) yöntemi önerilmiştir. Önerilen yöntem, literatürde iyi bilinen kıyaslama problemleri yardımı ile test edilmiştir. Elde edilen sonuçlar, Hibrit Uyarlanabilir Öğrenme Yaklaşım (HUÖY) algoritması ve Hibrit Karınca Kolonileri Optimizasyon (HKKO) algoritması ile kıyaslanmıştır. Amaç fonksiyonu olarak maksimum tamamlanma zamanının minimizasyonu seçilmiştir. Elde edilen çözüm sonuçları, önerilen HDA yönteminin BATÇ problemlerinin çözümünde etkili olduğunu göstermiştir..
Citation - WoS: 2
Citation - Scopus: 1
Bernstein-Walsh Polynomial Inequalities in Domains Bounded by Piecewise Asymptotically Conformal Curve With Nonzero Inner Angles in the Bergman Space
(SPRINGER, 2019) Abdullayev, F.G.; Abdullayev, G.A.; Şimşek, Dağıstan
We continue our investigation of the order of growth of the modulus of an arbitrary algebraic polynomial in the Bergman weight space, where the contour and weight functions have certain singularities. In particular, we deduce a Bernstein-Walsh-type pointwise estimate for algebraic polynomials in unbounded domains with piecewise asymptotically conformal curves with nonzero inner angles in the Bergman weight space.
Citation - WoS: 42
Citation - Scopus: 49
Bi-Objective Coordinated Production and Transportation Scheduling Problem With Sustainability: Formulation and Solution Approaches
(Taylor & Francis Ltd, 2023) Yağmur, Ece; Kesen, Saadettin Erhan
This paper studies a new variant of integrated production scheduling and vehicle routing problem where production of customer orders are performed under job-shop environment and order deliveries are made by a heterogeneous fleet of vehicles, each of which is allowed to take multiple trips. Two conflicting objectives are considered, namely minimisation of the total amount of CO2 emitted by the vehicles and minimisation of maximum tardiness resulting from late deliveries. To this end, we present a bi-objective mixed-integer programming formulation. Augmented epsilon-Constraint (Augmecon) method is implemented to find Pareto optimal solutions. Due to problem complexity, Augmecon cannot provide solutions even with small-sized problems. Thus, we adopt Pareto Local Search (PLS) and non-dominated sorting genetic algorithm-II (NSGA-II) for practical sized instances. For small-sized instances involving 5, 6, and 7 customers, experimental results indicate that CPU time of Augmecon are 11, 84, and 524 sec, respectively with an average number of Pareto efficient solution of 3.5. In terms of hypervolume index, Augmecon shows the best performance, followed by NSGA-II with 11.32% and PLS with 20.75% degradation for small-sized instances. For medium and large-sized instances, PLS shows worse performance than NSGA-II by 16.87% and 40.48%.
Citation - WoS: 1
Citation - Scopus: 1
Bi-Objective Optimization for Joint Production Scheduling and Distribution Problem With Sustainability
(SPRINGER INTERNATIONAL PUBLISHING AG, 2021) Yağmur, Ece; Kesen, Saadettin Erhan
This paper considers joint production and distribution planning problem with environmental factors. While the production phase of the problem consists of job shop production environment running under Just-In-Time (JIT) philosophy, the distribution phase involves a heterogeneous fleet of vehicles with regards to capacity and fuel consumption rate. Therefore, we tackle two well-known problems in Operations Research terminology which are called machine scheduling and vehicle routing problems. The joint problem is formulated as a bi-objective structure, the first of which is to minimize the maximum tardiness, the second of which aims to minimize the total amount of CO2 emitted by the vehicles. Orders are required to be consolidated to reduce the traveling time, distance, or cost. An increase in the vehicle capacity results in a higher possibility of consolidation, but in this case, the amount of CO2 emission that the vehicle emits into the air will also increase. Having shown that two objectives are conflicting in an illustrative example, we formulate the problem as amixed integer programming (MIP) formulation and use an Augmented Epsilon Constraint Method (AUGMECON) for solving the bi-objective model. On randomly generated test instances, the applicability of the MIP model through the use of AUGMECON is reported.
Citation - WoS: 112
Citation - Scopus: 138
Comparative Analysis of Topsis, Vikor and Copras Methods for the Covid-19 Regional Safety Assessment
(ELSEVIER SCIENCE LONDON, 2021) Hezer, Seda; Gelmez, Emel; Özceylan, Eren
COVID-19, which emerged in December 2019, has affected the entire world. Therefore, COVID-19 has been a subject of research in various disciplines, especially in the field of health. One of these studies was the report made by the Deep Knowledge Group (DKG) consortium in which safe regions for COVID19 were determined. In the report, the main criteria of quarantine efficiency, government efficiency of risk management, monitoring and detection, health readiness, regional resilience, and emergency preparedness are used in the evaluation of countries and regions (alternatives). As the data and research structure used in this report are based on multi-criteria, the purpose of this study is to evaluate and analyse the safety levels of 100 regions in the world in terms of COVID-19 using Technique for Order Performance by Similarity to Ideal Solution (TOPSIS), Vise Kriterijumsa Optimizacija I Kompromisno Resenje (VIKOR) and Complex Proportional Assessment (COPRAS) methods. The data and information required in the methods were obtained from a report prepared by the DKG. The results of the methods were compared with the ranking results presented in a report of the DKG. Accordingly, it has been observed that the method that provides the closest results to the results of the report is the COPRAS method, and the method that gives the most distant results is the VIKOR method. (c) 2021 The Authors. Published by Elsevier Ltd on behalf of King Saud Bin Abdulaziz University for Health Sciences. This is an open access article under the CC BY-NC-ND license (http://creativecommons. org/licenses/by-nc-nd/4.0/).
Citation - WoS: 20
Citation - Scopus: 24
Comparative Study on the Performances of Solar Air Collectors With Trapezoidal Corrugated and Flat Absorber Plates
(SPRINGER, 2020) Darıcı, Selçuk; Kılıç, Anıl
Thermal performance of the solar air collectors which are mostly used for space heating and drying is generally low. Therefore there are different studies aimed at increasing the thermal performance of the solar air collectors. One of the technics used for this purpose is making changes in surface geometry of the absorber plate. In this research, the thermal performance of two solar air collectors constructed with trapezoidal corrugated and flat absorber plate is investigated experimentally under weather conditions of Konya/Turkey. The experiments were conducted for three different air mass flow rates of 0.022, 0.033 and 0.044 kg/s. The results obtained are compared to the ones of solar air collector with flat absorber plate. It has been observed that difference between inlet and outlet air temperatures of the solar air collectors increases as the mass flow rate decreases. For the air mass flow rate of 0.022 kg/s, the maximum temperature rise in solar air collector with trapezoidal corrugated plate is 9 degrees C compared to the flat plate solar air collector. It has been shown that thermal performance of the solar air collectors rises with the increase in mass flow rates. It is determined that the average daily thermal efficiency of the solar air collector with trapezoidal absorber plate is 63% for 0.044 kg/s.
Citation - WoS: 5
Citation - Scopus: 4
Design, Manufacture and Thermal Analysis of a Single Pass Solar Air Collector at Different Mass Flow Rates
(GAZI UNIV, FAC ENGINEERING ARCHITECTURE, 2020) Darıcı, Selçuk
Solar air collectors are generally used for drying industrial and agricultural products or for space heating. Nowadays solar energy is paid more attention due to decrease in fossil fuels and increase in energy prices. In this study, a single pass, forced convective solar air collector has been designed, manufactured and analysed experimentally under climatic conditions of Konya/Turkey. Experiments have been conducted at three different mass flow rates, on different days and under clear weather conditions. Hourly variation of solar radiation, inlet and outlet air temperatures, glass cover temperature, absorber plate temperature and thermal efficiency of the solar air collector have been examined by using the experimental data obtained. It is seen that with the increase in mass flow rate, temperature of the air at the outlet of the collector decreases while thermal efficiency of the collector increases.
Citation - WoS: 1
Citation - Scopus: 3
Determination of Competencies With Fuzzy Multi-Criteria Decision Making Methods for Determining the Development Program for Analyst Position in a Participation Bank
(Springer Science and Business Media Deutschland GmbH, 2022) Yel, İbrahim; Sarucan, Ahmet; Baysal, Mehmet Emin
The management and training of human resources continues to increase in importance when considering the effects such as the increase in the demand for human resources in the field of information technologies during the pandemic process. Determining the competencies of the information technology personnel and developing the deficient ones according to the competencies can be considered as the main development policy. Based on this requirement, the problem of determining the competencies of system analysts at Kuveyt Türk Participation Bank is the main subject of this study. Within the scope of the study, a survey was conducted with the participation of 11 people with at least five years of experience in the analyst position on 24 core competencies. In line with the survey results, the importance weights of the competencies were determined with fuzzy AHP. Afterwards, 10 competencies with the highest weight among 24 core competencies were determined. Evaluations were made by five experts for system analysts working in an organization in the bank for the determined 10 competencies. Rankings of system analysts were made using Neutrosophic Z-Number sets (NZN) and Fuzzy EDAS methods. These rankings became an input to the competency development program that is planned to be prepared specifically for individuals. © 2022, The Author(s), under exclusive license to Springer Nature Switzerland AG.
Citation - Scopus: 1
Determination of the Best Alternative Position for the Storage Location/Product Assignment by Using Vikor
(Springer Science and Business Media Deutschland GmbH, 2022) Sarıcan, Bünyamin; Baysal, Mehmet Emin; Sarucan, A.
In this study, the best alternative location policy is determined by considering multiple criteria such as transportation distance, area of use, product demand, sensitivity, profitability and minimizing the cost incurred by a storage area. So, the best alternative policy is determined to apply a mathematical model that minimizes the transportation time or cost of warehouse allocation within the warehouse area by using multicriteria decision making (MCDM) methods. For optimal placement, a mathematical model proposed by Muppani and Adil is taken as reference which includes transportation distance, area and resulting cost items. According to the established criteria, harmonic solution values for each product were obtained from the VIKOR method and entered into the class formation and assignment model. The MCDM based on the class formation and assignment model was solved using the software GAMS/BARON. We randomly generated the data used for the solution. The results showed that we can assign the products to the warehouse by considering multiple criteria according to the preference of the decision maker. © 2022, The Author(s), under exclusive license to Springer Nature Switzerland AG.
Citation - Scopus: 13
Distributed Fuzzy Permutation Flow Shop Scheduling Problem: a Bee Colony Algorithm
(Springer, 2021) Baysal, M. Emin; Sarucan, A.; Büyüközkan, K.; Engin, O.
The distributed permutation flow shop scheduling problem is a subclass of the permutation flow shop scheduling problem. Distributed scheduling adopts multi-factory with permutation flow shop scheduling environment. At the distributed permutation flow shop scheduling, due to the human factors, the processing times of the jobs on the machines are not known exactly. Thus, in this study, the processing time of the jobs on machines are considered as a triangular fuzzy number. Also, the due dates of the jobs are considered as trapezoidal fuzzy numbers at this research. To solve the distributed fuzzy permutation flow shop scheduling problem with multi-objective an artificial bee colony algorithm is proposed. To the best of our knowledge, this is the first study to solve the distributed fuzzy permutation flow shop scheduling with an artificial bee colony algorithm. The proposed artificial bee colony algorithm is first calibrated on the distributed permutation flow shop scheduling problem. The results showed that the proposed artificial bee colony algorithm is an efficient solution technique for solving distributed fuzzy permutation flow shop scheduling problems. © 2021, The Editor(s) (if applicable) and The Author(s), under exclusive license to Springer Nature Switzerland AG.
Citation - WoS: 3
Citation - Scopus: 2
Distributed No-Wait Flow Shop With Fuzzy Environment
(Springer Science and Business Media Deutschland GmbH, 2022) Başar, Ramazan; Büyüközkan, K.; Engin, Orhan
In the no-wait flow shop scheduling problem, n-job should be proceeded on m-machine with the same order and do not permit the jobs to wait during the scheduling periods. Also, at the distributed no-wait flow shop scheduling problem, there are multi-factory for processing n-job with m-machine for no-wait constraint. In this study, distributed no-wit flow shop scheduling with the fuzzy due date is considered. The due date of the jobs is defined with fuzzy numbers. A parallel kangaroo algorithm is proposed to solve the distributed no-wait flow shop scheduling problem with the fuzzy due date. The proposed algorithm is tested from the literature by the benchmark problems. The results show that the proposed parallel kangaroo algorithm is efficient for distributed no-wit flow shop scheduling problems with fuzzy due date problems. © 2022, The Author(s), under exclusive license to Springer Nature Switzerland AG.
Citation - WoS: 2
Citation - Scopus: 1
Dynamical Behavior of Rational Difference Equation /+ 1 +/-(vol 27, 49, 2021)
(SPRINGER INT PUBL AG, 2021) Oğul, Burak; Şimşek, Dağıstan; Öğünmez, Hasan; Kurbanlı, Abdullah Selçuk
[Abstract Not Available]
Dynamical Behavior of Rational Difference Equation X(n+1) = X(n-15)/+ 1 +/- X(n-3)x(n
(SPRINGER INDIA, 2024) Oğul, Burak; Şimşek, Dağıstan; Kurbanlı, Abdullah Selçuk; Öğünmez, Hasan
In this paper, we study the qualitative behavior of the rational recursive sequences x(n+1) = x(n-15)/+/- 1 +/- x(n-3)x(n-7)x(n-11)x(n-15), n is an element of N-0 where the initial conditions are arbitrary real numbers. Also, we give the numerical examples and solutions graphs of some cases of difference equations.
Citation - WoS: 3
Citation - Scopus: 3
Estimation of Turkey’s Natural Gas Consumption by Machine Learning Techniques
(2020) Erdem, Osman Emin; Kesen, Saadettin Erhan
Technological advancements coupled with growing world population require the increasing need of energy. Natural gas is one of the most important usable energy resources. Turkey is with high external dependency on energy as it has its own limited natural and underground energy resources. Thus, in order to effectively and productively use of natural gas purchased from foreign countries and to make reliable and robust energy policies for the years ahead, it is crucial to make a reasonable and plausible prediction for natural gas consumption of Turkey. In this paper, we estimate the natural gas consumption using machine learning techniques on the basis of real monthly data representing natural gas consumption of Turkey between the years 2010 and 2018. The performances of machine learning techniques involving Artificial Neural Networks, Random Forest Tree, Regression, Time Series and Multiple Seasonality Time Series are compared in predicting the natural gas consumption of Turkey. Experimental results show that among the five techniques, artificial neural networks produce the best estimation, having the lowest mean square errors, followed by regression method. Time series shows the worst performance among all the techniques.

Browse

Browsing Mühendislik ve Doğa Bilimleri Fakültesi Koleksiyonu by Department "Fakülteler, Mühendislik ve Doğa Bilimleri Fakültesi, Endüstri Mühendisliği Bölümü"