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We focus on an assembly line design problem of a fully automated robotic spot-welding line. Different from existing studies, we take the prescheduled unavailability periods, such as lunch and tea breaks, into account in order to reflect a more realistic production environment. This problem includes allocating operations to the stations and satisfying the demand and cycle time within a desired interval for each model to be produced. We also ensure that assignability, precedence, and tool life constraints are met. Furthermore, the existing studies in the literature overlook the limited lives of the tools that are used for production. Tool replacement decisions not only affect the tooling cost, but also the production rate. Therefore, we determine the number of stations and allocate the operations into the stations in such a way that tool change periods coincide with the unavailability periods to eliminate tool change related line stoppages in a mixed model robotic assembly line. We provide a mathematical formulation, propose a two-stage local search algorithm and test the performances of these methods using different problem instances with varying parameters. The authors thank the associate editor, and four anonymous referees for their constructive comments and suggestions that significantly improved this paper. This research was partially supported by Tofas Turk Otomobil Fabrikasi A.S. (Fiat Turkey). We would like to thank Assoc. Prof. Dr. Orhan Alankus, Koc Holding, Strategic Planning Group, Technology and Environment Coordinator, and Tofas Turk Otomobil Fabrikasi A.S. (Fiat Turkey), Production Technology Department, for their continual support.

Bu tez çalışmasında çoklu robot sistemleri ile gerçek zamanlı olarak yapılan bir arama görevinde robotlar arası haberleşmenin sistem başarısına olan etkisi benzetimler ve robot uygulamaları yapılarak incelenmiştir. Yapılan ilk çalışmada engellerin bulunmadığı doğrusal bir alan üzerinde robotların iletişim kurabildiği ve kuramadığı iki farklı arama davranışı üzerinde durulmuş ve iletişimin arama başarısına olan etkisi ölçülmüştür. Devam eden çalışmalarda ise daha fazla sayıda robot kullanılarak üzerinde duvarlar ve engeller bulunan daha gerçekçi bir alan içerisinde arama davranışı gerçekleştirilmiş ve arama sırasında her bir robotun yaptığı arama ile ilgili harita bilgisini hafızasında tutması ve gerektiğinde bu bilgiyi iletişim mesafesinde bulunan diğer robotlarla paylaşması sağlanmıştır. Yapılan benzetim ve deneylerde çok robotlu işbirlikli bir arama senaryosunda robotlar arasındaki iletişim mesafesinin robotlar arasındaki işbirliğine ve dolaysıyla da arama başarımlarına olan etkisi ölçülmeye çalışılmıştır. Yapılan diğer bir çalışmada ise robotların sadece yaymış oldukları RF işaret şiddetleri kullanılarak ve başka herhangi bir konumlandırma yöntemi olmaksızın arama yapılacak ortama dağılmaları amaçlanmıştır. Burada dağılma davranışı doğada bakteriler gibi tek hücreli canlıların besin arama davranışlarından esinlenilerek geliştirilmiş bir yöntem olan bakteri beslenme eniyileme yöntemi kullanılarak robotların kendilerini istenilen şekilde konumlandırmaları ile sağlanmıştır. In this thesis the effects of communication on cooperative robotic search task is studied through both simulations and robotic experiments. Firstly, the benefits of networked communication are investigated by evaluating the results of communicative and non-communicative search by multi robot teams in a directional area without any obstacles. In the continuing studies the robotic search experiments are repeated with more robots and in a more realistic area containing walls and obstacles. During the search each robot is also allowed to keep an occupancy grid based map of the environment containing the information about the cells it has visited and to exchange this information with the other robots within its communication range. The effect of the size of communication range on the performance of the system defined as the time of completion the cooperative search task was investigated through both simulations and experiments. In the later part a robotic dispersion task which is a preliminary work for a robotic search is studied. During the dispersion of the robots any other positioning technique rather than the received radio signal strengths broadcasted from the other robots is not used. The dispersion of the robots is provided by using bacterial foraging algorithm which is an optimization method inspired from the foraging behaviors of mono-cellular microorganisms. https://tez.yok.gov.tr/UlusalTezMerkezi/tezSorguSonucYeni.jsp

Medical sciences and medical technologies are developing in an enormous pace. The number of multi-site and multi- cultural clinical trials is increasing in line with this development. Yet, the increase in number brought about a problem, namely that of inconsistencies in institutional review board (IRB) decisions. The efforts to develop a comprehensive and systematic framework for the decision-making procedure of IRB members were ineffective and ended up in form of lists containing general principles of research ethics. The increase in multi-site, multi-cultural clinical research together with the initiation of new institutional review boards in countries involved in these researches emphasize the importance of defining the sine qua non criteria for considering a proposed research study to be ethical, as well as for avoiding inconsistencies in institutional review board decisions. The aim of this study is to prepare a toolkit for IRB members to regulate the ethical decision-making process while minimizing inconsistencies in institutional review board decisions. The objective is to minimize the effect of subjective factors and to ensure that all issues in key international documents and guidelines are covered prior to the point of reaching a conclusion for the proposed research protocol. By providing a comprehensive review of the Declaration of Helsinki, Council For International Organizations of Medical Sciences Guidelines, International Conference on Harmonization Guidelines, Standards and Operational Guidance for Ethics Review of Health-related Research with Human Participants of World Health Organization, and Medical Ethics Manual of the World Medical Association, this study aims at developing a standard evaluation sheet for institutional review board members to evaluate the ethical appropriateness of proposed trial protocols (Tab. 1, Ref. 35). Keywords: clinical research, ethics review committee, human subjects, informed consent, institutional review board, research ethics.

Yer gözlem uydularınınn görev verimliliğiini artırabilmek için uydu görüntülerindeki bulutların hızlı bir şekilde tespit edilmesi önemlidir. Bu çalışmada orijinal görüntülerden 1/64 oranında küçük ebatlarda olan düşük frekanslı Ayrık Dalgacık Dönüşümü (ADD) bileşenlerinden bulut tespit etmeyi amaçlayan yeni bir yaklaşım önerilmiştir. Önerilen çözümde düşük frekanslı bileşenlerin bir takım doku öznitelikleri hesaplanmakta ve K-En Yakın Komşu (KEYK) sınıflandırıcısıyla bulutlu pikseller tespit edilmektedir. Önerilen yöntem Göktürk-2 görüntüleri üzerinde test edilmiştir. Düşük frekanslı ADD bileşenlerinin kullanılması önemli ölçüde detay kaybına yol açtığından; bulut tespit başarımı orijinal görüntülerin kullanımına kıyasla bir miktar düşmüştür. Bununla birlikte görüntülerdeki bulutluluk oranının az bir hata payıyla tespit edilebilmesine olanak sağlayacak sonuçlar elde edilmiş ve işleme hızı yaklaşık 145 kat gibi önemli bir artış göstermiştir Being able to rapidly detect clouds in satellite imagery is critical in terms of increasing mission efficiency of ground observation satellites. In this work, a new approach has been proposed for cloud detection involving the utilisation of lowfrequency Discrete Wavelet Transform (DWT) components whose sizes are 1/64 of the original image sizes. In the proposed method, several texture features are calculated from the low-frequency DWT components and the cloud pixels are detected by using a KNearest Neighbors (KNN) classifier. The proposed method has been tested on the Gokturk-2 images. Since the utilization of lowfrequency components leads to a significant loss in detail; the cloud detection performance have decreased to some extent. Nevertheless the obtained results were found to be sufficient for determining the cloudiness rate at a small margin of error, and at approximately 145x increased processing speed. 25th Signal Processing and Communications Applications Conference (SIU) (2017 : Antalya, TURKEY )

Abstract In cyclic scheduling of material handling robots in manufacturing cells, a common approach is to minimize the cycle time objective, which is a measure of the throughput of the cell. In a typical robot move cycle, robot move times constitute a significant portion of the cycle time. During handling operations, robots consume significant amount of energy, which is determined by their speed, load and the distance they travel. In this paper, we propose considering robot speed decisions along with robot move sequencing decisions in a robotic cell scheduling problem. We study the trade-off between the cycle time and the energy consumption of a robot in a robotic cell which produces identical parts. In this cell, the robot loads and unloads the machines. Each machine performs a different operation on a part and the robot moves linearly along a track. We provide models to find efficient solutions for cycle time and robot energy consumption objectives in an m-machine robotic cell. In a case study for two machine robotic cell, we show that robot speed control can lead to significant savings in energy consumption.

The aim of this study is to investigate the digital transformation process which is witnessed by the whole world and how SMEs - operating in our country - are positioning in this transformation process. Within the scope of "Digital Transformation Movement" project which is collaboratively carried out by The Union of Chambers and Commodity Exchanges of Turkey (TOBB) and Vodafone, online survey was applied to SMEs. By randomly selecting 250 surveys (sampling) out of a data pool formed by scattered companies based on the online survey, with a 5 percent margin of error (sample) with a 95 percent confidence level, the data is statistically analyzed by using SPSS 19.0 program. In this study, which has an exploratory feature, ANOVA and hierarchical regression, factor analysis and cluster analysis are used. Based on the regression analysis, it is concluded that the budget allocated to the technology has an effect on the digital score. In addition, it is also observed that if the number of employees, i.e. firm size, increases, the effect of the budget allocated to technology on digital score increases. When the analyzes are examined in terms of the service and production sector, it is concluded that the effect of the budget allocated for technology in the service sector on the digital score increases while there is no relationship in the production sector. The study consists of five parts. After the introduction, the concept of digitalization is defined in the second section, and the history of digitalization and its trends in the world are examined. Again in this section, the importance of digitalization and its effects on companies and the commercial ecosystem are explained. In the third section, the concept of SMEs is defined and various data on the use of technology by SMEs have been examined. In the fourth part, the results of the survey conducted with 250 companies within the scope of TOBB Digital Transformation Movement are analyzed. In the last part of the study, suggestions for the digitalization of SMEs are presented by evaluating the results of the analyzes. Çalışmanın amacı tüm dünyanın tanık olduğu dijital dönüşüm süreci ve ülkemizde faaliyet gösteren KOBİ'lerin bu dönüşüm sürecinde nasıl konumlandıklarını incelemektir. Türkiye Odalar ve Borsalar Birliği (TOBB) ve Vodafone iş birliğiyle yürütülen "Dijital Dönüşüm Hareketi" projesi kapsamında KOBİ'lere çevrimiçi anket uygulanmıştır. Bu yöntem ile toplanan ve dağınık özellikteki firmaların bir araya getirilmesiyle oluşan veri havuzundan rastgele seçilen (evren) temsil yetkisine sahip yüzde 95 güven düzeyinde yüzde 5 hata payı ile 250 adet anket sonucu (örneklem), SPSS 19.0 programı ile istatistiksel analize tabi tutulmuştur. Keşfedici bir özellik taşıyan bu çalışmada ANOVA ve hiyerarşik regresyon ile faktör analizi ve kümeleme analizi yapılmıştır. Regresyon analizi ile teknolojiye ayrılan bütçenin dijital skor üzerinde etkili olduğu sonucuna ulaşılmıştır. Bunun yanı sıra çalışan sayısı yani firma büyüklüğü arttıkça teknolojiye ayrılan bütçenin dijital skor üzerindeki etkisinin arttığı gözlemlenmiştir. Analizler hizmet ve üretim sektörü özelinde incelediğinde, hizmet sektöründe de teknolojiye ayrılan bütçenin dijital skor üzerindeki etkisi artarken üretim sektöründe böyle bir ilişkinin olmadığı görülmektedir. Çalışma beş bölümden oluşmaktadır. Giriş bölümünün ardından ikinci bölümünde dijitalleşme kavramı tanımlanarak, dijitalleşme tarihi ve dünyadaki trendleri incelenmiştir. Yine bu bölümde dijitalleşmenin önemi ile şirketler ve ticari ekosistem üzerindeki etkileri anlatılmaktadır. Üçüncü bölümde KOBİ kavramı tanımlanarak, KOBİ'lerin teknoloji kullanımına yönelik çeşitli veriler incelenmiştir. Dördüncü bölümde TOBB Dijital Dönüşüm Hareketi kapsamında 250 firma ile gerçekleştirilen anket sonuçları analiz edilmiştir. Çalışmanın son bölümünde ise analizlerin sonuçları değerlendirilerek KOBİ'lerin dijitalleşmesine yönelik öneriler sunulmaktadır.

Kullanıcıların internete bağlı nesnelerin konfigürasyonlarında basit parolalar seçmesi veya bu cihazlarla birlikte gelen varsayılan parolaları değiştirmemeleri ciddi güvenlik açıkları yaratmaktadır. Mirai vb. zararlı yazılımlar bu açıklıkları sömürerek çevrim içi nesneleri ele geçirmekte ve dağıtık servis dışı bırakma saldırılarında saldırı unsuru olarak kullanarak hizmet kesintilerine, maddi kayıplara ve itibar zedelenmesine neden olmaktadır. Bu çalışmada kullanıcıların nesnelerin internetine yönelik güvenlik ve risk algılarının, parola kullanımı ve güvenliğine dair tercihlerinin tespit edilmesi amaçlanmıştır. Katılımcılardan anket yöntemi ile veri toplanarak elde edilen bulgular tartışılmıştır. Configuring internet of things (IoT) devices with easy or default passwords leads to serious vulnerabilities. In recent years, malware (Mirai etc.) which are capable of creating IoT botnets and organizing distributed denial of service (DDoS) attacks have given rise to service disruptions, reputational and financial loss. In this study, we aimed to determine users' perceptions of security and risks related to IoT devices, preferences of password usage and password security. A questionnaire was employed to collect data and findings were discussed. 4th International Conference on Computer Science and Engineering, UBMK (2019: Samsun, Turkey)

IoT-enabled home appliances are still in their infancy, especially from the perspective of customers, which hinders widespread market penetration. To relieve this skeptical attitude of customers toward IoT appliances, it is important to design human-centric business models rather than corporate-centric ones. IoT ecosystems that make use of cognitive outputs from the social network of things can assist in the establishment of such business models. The contributions of this article are twofold. First, we propose a reference model that grants the absolute ownership of the fog-located digital twin (DT) of a home appliance to its owner and promotes human-centric services and applications on this twin by utilizing blockchains (BCs) and BC-enabled clouds. Second, by enabling customers to have absolute ownership rights over the fog-located DTs, the model paves the way for the liberalization of DTs as well as the appliances coupled to them, which is an important step in revealing the true value that underlies human-centricity and things-to-things collaboration.

In Wireless Sensor Networks (WSNs) data transmission by using the highest available power level leads to energy wastage on certain links. Therefore, assigning the optimal transmission power for each link in a WSN is necessary to prolong the network lifetime. Transceivers of WSN nodes perform transmission power control by selecting one of the available discrete transmission power levels. As such, the power level set of a WSN transceiver is an important tool for achieving energy efficiency, yet, the power level sets are determined without considering their effects on WSN lifetime. In this study, we investigate the characteristics of the optimal transmission power level sets from WSN lifetime maximization perspective. 15th IEEE Sensors Conference (2016 : Orlando, FL)