Endüstri Mühendisliği Bölümü

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Citation - Scopus: 2
A Multiple Criteria Ranking Method Based on Outranking Relations: An Extension for Prospect Theory
(Springer Science and Business Media Deutschland GmbH, 2022) Karasakal, E.; Karasakal, Orhan; Karasakal, O.; Şentürk, H.; 216553; Endüstri Mühendisliği
In this study, Prospect Theory is integrated into a well-known multiple criteria ranking method, PROMETHEE. PROMETHEE considers the outranking relations among alternatives based on the preference functions. Prospect Theory evaluates the alternatives with a difference function based on gains and losses. The preference functions of PROMETHEE are modified to capture the choice behavior of the decision maker. The proposed method is a generalization of PROMETHEE that can handle the higher loss impact case as well as the usual equal loss and gain impact. The proposed method is compared with PROMETHEE, PT-PROMETHEE that is an extension of PROMETHEE with reference alternative, and the weighted sum method using an exemplary data set and Times Higher Education (THE) World University Ranking 2019 and 2020 data. The results show that rankings of alternatives change significantly when the impact of losses is larger than gains. © 2022, The Author(s), under exclusive license to Springer Nature Switzerland AG.
Citation - WoS: 0
Citation - Scopus: 2
A Paradox of the Average Waiting Time for the Case of a Single Bottleneck on the Commuters' Route
(Hindawi Ltd, 2021) Ozaktas, Hakan; Kırkavak, Nureddin; Kirkavak, Nureddin; Alpay, Ayse Nilay; 58272; Endüstri Mühendisliği
Average waiting time is considered as one of the basic performance indicators for a bottleneck zone on a route for commuter traffic. It turns out that the average waiting time in a queue remains paradoxically unchanged regardless of how fast the queue dissolves for a single bottleneck problem. In this study, the paradox is verified theoretically for the deterministic case with constant arrival and departure rates. Consistent results with the deterministic case have also been obtained by simulation runs for which vehicle interarrival time is a random variable. Results are tabulated for interarrival times which have uniform, triangular, normal, and exponential distributions along with a statistical verification of the average waiting time paradox.
Citation - WoS: 0
A Petri Net-based inference network for design automation under nondeterminism applied to mechatronic systems
(Pergamon Press Ltd, 1998) Erden, Z; Erkmen, AM; Erden, A
This paper introduces the completed part of an ongoing research, in which a Petri Net-based design inference network is developed for the representation and analysis of the functions and their interrelationships through information flow for the conceptual design stage of mechatronic systems in order to facilitate design automation. The theoretical framework behind the network is based on transition of Hybrid Automata into Petri Nets and application of this framework is introduced by a mechatronic design example.
Citation - Scopus: 2
A Systems Approach for Technology Assessment and Selection
(2012) Demirkiran, Z.K.; Altunok, Taner; Altunok, T.; Makine Mühendisliği
Each system development project necessitates making decisions on the selection of technologies among available alternatives for the system and is covered in the technology assessment phase in the acquisition process. For the assessment very limited numbers of methodologies most of which are qualitative are defined in the literature. This study aims to propose a systematic model, which can be used as a guide by planners or system architects in the multi-criteria technology selection process. The model also proposes a method to define the critical technology elements for a system. A case study on Unmanned Aerial Vehicle (UAV) communication systems is presented to illustrate the applicability of the model. © 2012 IEEE.
Citation - WoS: 29
Citation - Scopus: 33
An Auction-Based Framework for Resource Allocation in Disaster Relief
(Emerald Group Publishing Ltd, 2011) Ertem, Mustafa Alp; Ertem, Mustafa Alp; Buyurgan, Nebil; 52460; Endüstri Mühendisliği
Purpose - The purpose of this paper is to address the inefficiency problems in procurement operations in disaster relief logistics which are mainly due to the lack of coordination among less organized suppliers and partnerships. Such problems lead to poor responsiveness and hinder timely procurement of required goods. Design/methodology/approach - An auction-based framework for procurement of goods, which is suitable for a single coordinating platform in disaster relief logistics, is proposed. Integer programming formulations are used in auctioning operations. A simulation model that generates problem instances is used to evaluate and tune system-level design parameters. Findings - Design parameters greatly affect the behaviour and responsiveness of the system and the performance of the auction-based framework in different problem instances. Combinations of those parameters may allow suppliers with limited capacities to become more involved in the bidding process. In addition, the procurement shares of bidders may change substantially with different values of the parameters. Research limitations/implications - Even though the presented framework is inspired from reallife applications, it is not implemented in real-life disaster relief operations. The goodness of fit for the framework would best be evaluated by a real disaster case. In addition, transportation scheduling and vehicle routing considerations and budgeting issues are not considered in the framework. Originality/value - This paper presents an auction-based framework for less organized suppliers of goods and their partnerships, such as local humanitarian organizations, private companies, and standby partners. The presented framework offers a background for coordination during disaster relief operations which provides opportunities to act as a set of organized entities. This background also helps those entities coordinate their efforts to enhance the capabilities of local governments and NGOs.
Citation - Scopus: 16
Analysis of barriers to the adoption of circular supply chain management: a case study in the air conditioning industry
(Taylor and Francis Ltd., 2023) Çıkmak, S.; Kesici, B.
Circular supply chain management (CSCM) is a process used to design the supply chain by recycling, remanufacturing or refurbishing, repairing, and reusing products However, no study has been encountered in the literature that analyzes CSCM barriers in the air conditioning sector. Hence, this study is aimed to investigate the barriers to CSCM adoption in the air conditioning industry. A case study was conducted on a company operating in the global air conditioning sector. Initially, literature review and expert opinions have been used to identify essential barriers. Later, 6 main barriers and 21 sub-barriers were ranked using Analytical Hierarchy Process (AHP) method based on the interval type-2 fuzzy sets. The findings indicate that “Regulatory” is the most crucial, and “Operational” is the least important main barrier. The findings of the study would be useful for practitioners and policymakers to focus on the most prominent barriers in the air conditioning supply chains. © 2023 Chinese Institute of Industrial Engineers.
Citation - WoS: 18
Citation - Scopus: 34
Comparison of globoid and cylindrical shearer drums' loading performance
(South African inst Mining Metallurgy, 2006) Ayhan, M; Eyyuboglu, EM; 5072
Drums of a modern longwall shearer are manufactured to include various constructional features conveying extracted material onto the face conveyor as efficiently as possible. Designing a drum with a conical shell or with reduced vane length, consequently with a stepper vane angle, is the most widely employed method in an attempt to increase loading efficiency. This study compares loading performances of two such drums, one having a conical shell with modified loading vanes, the other with a cylindrical shell with reduced vane length, Firstly, the loading performances of drums are predicted and the maximum haulage rate attainable with the drums are calculated. Then the performances of drum are compared by long-term comprehensive underground trials with coal shearers under similar conditions during the production operation of Park Termik Cayirhan coalmine in Turkey. Although higher loading performance is predicted for cylindrical drums, the in situ trials point out that Globoid drums have a slightly higher loading performance than cylindrical drums. Furthermore, the relationship between operational variables, i.e. extraction height, sumping depth, haulage rate and in situ loading performance, were investigated statistically on the basis of data gathered during the underground trials.
Citation - WoS: 1
Comparison on Solving a Class of Nonlinear Systems of Partial Differential Equations and Multiple Solutions of Second Order Differential Equations
(Springer international Publishing Ag, 2019) Akgul, Ali; Baleanu, Dumitru; Akgul, Esra Karatas; Khan, Yasir; Baleanu, Dumitru; 56389; Matematik
Citation - WoS: 3
Cyclical Behavior of Stock ExchangeIndex By Sectors: A Case From Turkey
(Elsevier Science Bv, 2012) Yuksel, Ebru; Bayrak, Ozlem Turker; 18500
In this study, the relation between the cyclical behaviors of stock market indices of industry, service, finance and technology sectors at Istanbul Stock Exchange and gross domestic product of Turkey between the 1998 January and 2011 September, is analyzed. The results suggest that stock exchange indices move in the same direction with economic activity and stock market leads the economy by about one quarter. However, when the sectoral differences are considered, movements in technology sector index are transmitted to economy in two months whereas it is three months for the industrial and service sector. The slowest sector is the financial sector for which pass-through speed is four months. (C) 2012 Published by Elsevier Ltd. Selection and/or peer review under responsibility of Prof. Dr. Huseyin Arasli
Citation - WoS: 0
Differential Algebraic Equations in Primal Dual Interior Point Optimization Methods
(Amer inst Physics, 2004) Kasap, S; Kasap, Suat; Trafalis, TB; Endüstri Mühendisliği
Primal dual Interior Point Methods (IPMs) generate points that lie in the neighborhood of the central trajectory. The key ingredient of the primal dual IPMs is the parameterization of the central trajectory. A new approach to the parameterization of the central trajectory is presented. Instead of parameterizing the central trajectory by the barrier parameter, it is parameterized by the time by describing a continuous dynamical system. Specifically, a new update rule based on the solution of an ordinary differential equation for the barrier parameter of the primal dual IPMs is presented. The resulting ordinary differential equation combined with the first order Karush-Kuhn-Tucker (KKT) conditions, which are algebraic equations, are called differential algebraic equations (DAEs). By solving DAEs, we find an optimal solution to the given problem.
Citation - WoS: 15
Citation - Scopus: 12
Effects of adopting inflation targeting regimes on inflation variability
(Elsevier Science Bv, 2007) Berument, Hakan; Yuksel, Ebru; 160534; 18500
This paper investigates whether inflation-targeting programs have altered the pattern of inflation and its variability for five developed countries and four emerging economies implementing inflation-targeting programs. A GARCH specification is used to model inflation variability, which accounts for public perception of the future levels of inflation variability-conditional variance. We could not find lower conditional inflation expectations except for Australia, Chile and Sweden under various specifications. Moreover, the conditional variance decreases only for Chile and the UK. Therefore, the empirical support for the lower inflation and its variability for the inflation targeting regimes is limited. (c) 2006 Elsevier B.V. All rights reserved.
Citation - Scopus: 1
Enhanced nutrients removal in conventional anaerobic digestion processes
(2009) Othman, M.Z.; Uludag-Demirer, S.; Demirer, G.N.
One of the main challenges for one phase anaerobic digestion processes is the high concentration of NH 4 + and PO 4 3- ions in the digested sludge supernatant. This project focuses on enhancing the removal of nutrients during the anaerobic digestion process through fixing both NH 4 + and PO 4 3- ions in the form of struvite (magnesium ammonium phosphate, MAP, MgNH 4PO 4.6H 2O) within the anaerobic sludge. Batch anaerobic digestion tests showed that Mg 2+ concentration in the range 279 - 812 mg/L had insignificant effect on CGP but incurred a slight increase in COD removal. The reactor that had soluble Mg 2+:NH 4 +:PO 4 3- at a molar ratio of 1.28:1:00:1:00 achieved the best performance enhancement of 8% increase in COD removal and 32% reduction in NH 4 + in the reactor supernatant. Overall, the results show that there is a potential to optimise conventional anaerobic digestion such that supernatant lean in P and N, and sludge rich in nutrients are obtained.
Citation - Scopus: 0
Forecasting day of week volume fluctuations in the intermodal freight transportation
(Institute of Industrial Engineers, 2011) Ertem, M.A.; Ertem, Mustafa Alp; 52460; Endüstri Mühendisliği
Average daily volume fluctuates intensely based on the day of week in the intermodal freight transportation. Shippers tend to peak around Thursdays and receivers tend to peak around Mondays. These fluctuations bring challenges to the industry in terms of capacity management and getting reliable service from the railroad companies. The purpose of this study is to forecast J. B. Hunt Transport Services, Inc.'s load volume on railroads. Load is meant to be the number of containers that will arrive at a rail ramp during a 24hrs time window. The end in mind is to have better service from the railroad companies and to manage the company owned equipment better. The forecasting model applied to tackle this problem is a multiple linear regression model and is based on the historical in-gate numbers. It uses the previous two year's data and day of week information as independent variables, and current year's data as the response variable. The results indicate better accuracy levels for the model when compared to the two week moving average.
Citation - Scopus: 0
Heterogeneous Sensor Data Fusion for Target Classification Using Adaptive Distance Function
(Springer Science and Business Media Deutschland GmbH, 2021) Atıcı, B.; Karasakal, Orhan; Karasakal, E.; Karasakal, O.; 216553; Endüstri Mühendisliği
Automatic Target Recognition (ATR) systems are used as decision support systems to classify the potential targets in military applications. These systems are composed of four phases, which are selection of sensors, preprocessing of radar data, feature extraction and selection, and processing of features to classify potential targets. In this study, the classification phase of an ATR system having heterogeneous sensors is considered. We propose novel multiple criteria classification methods based on the modified Dempster–Shafer theory. Ensemble of classifiers is used as the first step probabilistic classification algorithm. Artificial neural network and support vector machine are employed in the ensemble. Each non-imaginary dataset coming from heterogeneous sensors is classified by both classifiers in the ensemble, and the classification result that has a higher accuracy ratio is chosen for each of the sensors. The proposed data fusion algorithms are used to combine the sensors’ results to reach the final class of the target. We present extensive computational results that show the merits of the proposed algorithms. © 2021, Springer Nature Switzerland AG.
Citation - Scopus: 1
Identification of eco-efficiency opportunities in a small enterprise producing vegetable oil in Eskisehir, Turkey
(Inderscience Publishers, 2007) Tepe, N.; Uludaǧ-Demirer, S.
In this study, the current processes and technologies in a small enterprise, Demircanlar Oil Industry1 (Eskisehir, Turkey), were audited and improved from the eco-efficiency point of view. The eco-efficient management of the vegetable oil production processes has been performed on the units of physical processes, extraction and purification. The results obtained indicated that the loss in raw material can be reduced simply by increasing me height of the sieves used to separate foreign materials (leaves, sand, stones, etc.) from sunflower seeds. Results also indicated that production costs and negative environmental impacts can be decreased by minimising the loss of hexane during the extraction process, and the product quality can be improved and product loss can be prevented by adjusting the amounts of bleaching clay and TriSyl® in me bleaching process. Although the reduction in environmental impacts of the factory could not be valuated, the study showed that the factory can be managed more eco-efficiently without undergoing major process changes with an immediate benefit of approximately 12,000 USD. Copyright © 2007 Inderscience Enterprises Ltd.
Kamu Kurumlarında Risk Değerlendirmesi İçin Karar Destek Sistemi Önerisi
(2018) Tok, Elif Gülce; Satır, Benhür; Satır, Benhür; 54700; Endüstri Mühendisliği
6331 Sayılı İş Sağlığı ve Güvenliği (İSG) Kanunu’nun 31.12.2012’de yürürlüğegirmesinden itibaren risk değerlendirmesi bütün işyerlerinde zorunlu halegelmiştir. Bu çalışmada iş sağlığı ve güvenliğinin önemli bir öğesi olan riskdeğerlendirmesinin kamu kurumlarında yapılmasını daha sağlıklı hale getirecekve kolaylaştıracak bir rehber hazırlanmıştır. Bu rehber bir kontrol listesi ve ilgilirisk tablosundan oluşmaktadır. Gerek ülkemizdeki 6331 Sayılı İSG Kanununda veilgili yönetmeliklerde, gerekse de OHSAS 18001 İSG Yönetim Sisteminde, sürekliiyileştirmenin önemi açıkça görülmektedir. Bu çalışmada hazırlanan rehberinuygulanmasında riskin kabul edilebilir seviyeye inene kadar risk değerlendirmesiniizlemeyi sistemli ve kolay hale getirerek sürekli iyileştirmenin gereklerini sağlamaküzere bir Karar Destek Sistemi önerilmiştir. Birim, kaynak ve tehlike parametreleribir bütün olarak ele alınarak BKT olarak değerlendirilmiş ve sistemin veri tabanıaltyapısı bunun üzerine kurulmuştur. Risk değerlendirmesinin ana öğeleri olan BKT,risk ve önlem ilişkilerinin Varlık-İlişki Çiziti hazırlanarak en büyük ve en küçükkardinallik oranları her ilişki arasında tanımlanmıştır. Fikir vermesi açısından bazı kullanıcı arayüzleri tasarlanmış ve önerilmiştir. Farklı sektörlerde yapılmış benzerçalışmalar mevcuttur ancak gerek kamu kurumları düşünüldüğünde gerekse deuygulama için önerilen karar destek sistemi düşünüldüğünde bu çalışma bilgimizdahilinde literatürdeki ilk çalışmadır.
Katı Atık Depolama Tesisi Yer Seçimi için Birleştirilmiş Hedef Programlama ve AHP Yaklaşımı
(2019) Aydemir-karadag, Ayyuce; 116059
Tüm dünyada, nüfus ve kentleşmenin artması ve gelişen teknoloji ile beraber üretilen atık miktarı da artmaktadır. Katı atıkların bertarafı, büyük oranda düzenli depolama yöntemiyle sağlanmaktadır. Bir düzenli depolama sahasının uygun şekilde projelendirilmesi ve işletilmesi için en önemli ön şart uygun kuruluş yeri seçiminin yapılmasıdır. Sağlıklı, verimli, uzun ömürlü, sürdürülebilir ve yasal düzenlere uygun düzenli depolama yer seçimi çok kriterli bir karar problemidir. Bu çalışmada; Ankara ili ve çevresinde kurulabilecek katı atık düzenli depolama tesisi kuruluş yeri alternatifleri, çevresel, ekonomik, sosyal ve zeminsel kriterler açısından Analitik Hiyerarşi Prosesi (AHP) ile değerlendirilmiştir. Ankara'nın yıllık depolanan atık talebini karşılayacak alternatiflerin arasından seçim yapılması, AHP ile hesaplanan kriter ağırlıklarını ve alternatif önceliklerini kullanan ve sistem gerçeklerini yansıtan hedef programlama (HP) modeli ile sağlanır.
Citation - Scopus: 1
Multi-manned assembly line balancing problems with sequence-dependent setup times
(Curran Associates Inc., 2017) Güner, F.; Güner, Funda; Kellegöz, T.; Toklu, B.; 17931; Çankaya Meslek Yüksekokulu
In the production of large-size products (such as automobiles, buses, trucks etc.), designing assembly lines with multi-manned workstations may provide decreasing number of total workstations, requirement of large plant area and product flow time. Depending on the characteristics of the tasks about to be started and the one just completed on the same worker, setup times may be significant. Therefore, in some real life situations, it is possible to see setup times between tasks processed successively. In this study, assembly line balancing problems with multi-manned workstations and sequence dependent setup times are addressed. The formal definition of the problem is firstly presented. Then, its mixed integer programming formulation and is developed. In the computational study, by using these formulations, a set of test instances is solved, and results are provided.
Citation - Scopus: 12
On periodic solutions of linear impulsive delay differential systems
(2008) Akhmet, M.U.; Alzabut, J.O.; Zafer, A.; 351454
A necessary and sufficient condition is established for the existence of periodic solutions of linear impulsive delay differential systems. Copyright © 2008 Watam Press.
Citation - WoS: 4
Citation - Scopus: 3
Optimum bidding strategy for wind and solar power plants in day-ahead electricity market
(Springer Heidelberg, 2021) Ozcan, Mehmet; Satır, Benhür; Keysan, Ozan; Satir, Benhur; 54700; Endüstri Mühendisliği
There are two possible strategies for wind power plants (WPPs) and solar power plants (SPPs) to maximize their income in day ahead markets (DAM) in the presence of imbalance cost: joint bidding (JB) via collaboration by participating to balancing groups and deployment of storage technologies. There are limited studies in the literature covering the comparative analysis of "JB strategy" with "battery deployment (BD) strategy". In the existence of balancing responsibility, the comparative analysis of these strategies is the main contribution of this study to the literature. Our Second contribution is the analysis of the impact of different regulatory regimes, which are set by the regulatory authority, on total income. JBM (joint bidding model), which is the model for joint bidding via different collaboration groups, is developed for the analysis of JB strategy, BDM (battery deployment model), which is the model covering the deployment of storage technology, is developed for the analysis of BD strategy. The impact of each strategy on total income is analyzed. According to the analysis of the results of the models, while JB strategy, which is sensitive to the regulatory regime, increases the total annual income of the collaboration groups up to 0.65%, BD strategy seems not feasible and financially viable. On the other hand, extra income values per MW of battery for SPP is between $218 and $400 /MW-year, while these values are between $2460 and $6795/MW-year for the group of 15 WPPs. Therefore, deployment of battery for WPPs creates extra income more than tenfold of that of SPP. BD strategy can be viable provided that the levelized cost of deployment of battery drops below the extra income values achieved per MW of battery.

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