Yüksek Lisans Tezleri

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Citation - Scopus: 5
Active Defense Strategy Against Jamming Attack in Wireless Sensor Networks
(Modern Education and Computer Science Press, 2019) Al-Shai, N.F.A.; Hassanpour, R.
Wireless Sensor Networks WSNs are being utilized increasingly nowadays due to their ability to collect data from stationary, moving, reachable or unreachable fields. Progressive developments in WSN techniques add efficiency, reliability and better power management possibility, but they are still vulnerable and sensitive to security threats. The most effective threat to WSN is DOS attacks, which are detectable but in many cases unpreventable yet. An authentication-based defensive approach against DOS attack combined with jamming attack that prevents transferring data between attacked nodes in a cluster and cluster head node is proposed in this study. The proposed method encompasses developing an algorithm with ability to bypass attacked path via alternative safe one under control of cluster head to mitigate the False Node Excluding DOS due to jamming attack. The proposed method has been experimentally tested against similar methods from the literature with arbitrary study cases. Our proposed algorithm shows promising results in mitigating False Node Exclusion DOS (FNEDOS) attack where a full recovery of the attacked node is achieved in case of isolated nodes, and improvement between 36% and 52% is obtained when the attack affects a group of nodes at proxim © 2019 MECS.
Adoption of Case Tools & Uml: a Local Study
(Association for Computing Machinery, 2020) Ashour, O.I.A.; Pusatli, T.
This research investigates the role of CASE tools in the software development process by considering importance of CASE in adopting a number of standards. A survey was conducted in six selected companies in Ankara in which semi-structured interviews are conducted with information system managers and developers as key informants. As results, CASE and UML are reported as being considerably used in Ankara with CASE tools being used for project members' communication and documentations. Furthermore, CASE tools have been used for some companies for documentation as parts of contracts and to follow standards such as ISO and CMMI. CASE tools are used to facilitate project developments, especially when enforced by the standards and methodologies required in the contracts. © 2020 ACM.
Decoding of Polar Codes
(Springer Science and Business Media B.V., 2019) Gazi, O.
As we explained in Chap. 1, polar encoder structures can be constructed in a recursive manner. This leads to recursive decoding structures. In [1], Arıkan proposed successive cancellation decoding algorithm for the decoding of polar codes and derived recursive expression for the decoding operations. © Springer Nature Singapore Pte Ltd. 2019.
Citation - Scopus: 5
Deep Learning Methods With Pre-Trained Word Embeddings and Pre-Trained Transformers for Extreme Multi-Label Text Classification
(Institute of Electrical and Electronics Engineers Inc., 2021) Erciyes, N.E.; Görür, A.K.
In recent years, there has been a considerable increase in textual documents online. This increase requires the creation of highly improved machine learning methods to classify text in many different domains. The effectiveness of these machine learning methods depends on the model capacity to understand the complex nature of the unstructured data and the relations of features that exist. Many different machine learning methods were proposed for a long time to solve text classification problems, such as SVM, kNN, and Rocchio classification. These shallow learning methods have achieved doubtless success in many different domains. For big and unstructured data like text, deep learning methods which can learn representations and features from the input data wtihout using any feature extraction methods have shown to be one of the major solutions. In this study, we explore the accuracy of recent recommended deep learning methods for multi-label text classification starting with simple RNN, CNN models to pretrained transformer models. We evaluated these methods' performances by computing multi-label evaluation metrics and compared the results with the previous studies. © 2021 IEEE
Expert System for Access Telecommunication Networks
(2009) Şahin, S.; Tolun, M.R.; Baykal, Y.
Access telecommunication systems are categorized as digital subscriber line (xDSL), fiber-to-the-home (FTTH), hybrid fiber-coaxial (HFC), power line systems, local multipoint distribution system (LMDS), free space optics (FSO), satellite and worldwide interoperability for microwave access (WIMAX) systems. Basic specifications, such as the rate of information for upstream and downstream, access link length, frequency licence requirement for these access telecommunication networks are defined. Expert system analysis is applied to find out the possible systems that can be employed among the abovementioned choices of access telecommunication within the user defined inputs describing the requirements of the end user. The rule-based structure of the expert system is formed by using the Exsys expert system development tool. © 2008 IEEE.
Citation - WoS: 20
Citation - Scopus: 20
Influence of Welding on Microstructure and Strength of Rail Steel
(Elsevier Sci Ltd, 2020) Turkbas, Osman Selim; Cogun, Can; Sarikavak, Yasin
In this study, metallurgical and mechanical aspects of cold flash butt welded rail joints were investigated. The relationship between the material characteristics and the distance to the fusion line were evaluated. Significant changes observed in grain size as it ranges 2-8 according to ASTM E 112. Hardness tests conducted and the average results of the rail head, web, and foot were recorded. According to the results, three different zones were identified including the fusion line, recrystallization zone, and transition areas. Tensile properties and strength characteristics have been investigated for the specified zones separately. Obtained experimental values were used as input parameters for the developed finite element model (FEM) to calculate stress distribution. The welded rail was subjected to realistic wheel load and stress distributions in weld were evaluated. The developed model has also been validated by comparing the theoretically obtained stress values with the experimental ones under various loading conditions. (C) 2020 Elsevier Ltd. All rights reserved.
Citation - Scopus: 5
Investigating End User Errors in Oil and Gas Critical Control Systems
(Association for Computing Machinery, 2020) Alrawi, L.N.; Pusatli, T.
System availability and efficiency are critical in the petroleum sector as any fault affecting those systems may negatively impact operations resources, such as money, human resources and time. Therefore, it has become important to investigate the reasons for such errors. In this study, human error has been targeted since a number of these errors is projected to increase in the sector. The factors that affect end user behavior are investigated in addition to an evaluation of the relation between system availability and human behavior. An investigation has been performed following the descriptive methodology in order to gain insights into human error factors. Questionnaires related to software/hardware errors and errors due to the end user were collected from 81 site workers. The findings indicate a potential relation between end user behavior and system availability. Training, experience, education, work shifts, system interface, usage of memory sticks and I/O devices were identified as factors affecting end user behavior, hence system availability and efficiency. © 2020 ACM.
Maintaining Cybersecurity Awareness in Large-Scale Organizations: a Pilot Study in a Public Institution
(IGI Global, 2023) Aslan, M.; Pusatli, T.
Research was conducted to increase the awareness of employees with regard to cyber security to fill the gap in the literature where few studies on how effective the measures implemented in organizations were reported. This research uses the outcome of the phishing drills that a public institution applied to its personnel, participation of said personnel in awareness training, and the reading statistics of regularly published information security bulletins. This has been beneficial in determining the methods to increase the cyber security awareness of personnel in organizations with 1,000 or more personnel; users were considered as a whole, and not individually evaluated. Findings report that organizations can increase users' cybersecurity awareness by systematically conducting phishing exercises, providing awareness training, and regularly publishing information security bulletins. The awareness of reading bulletins rapidly increased after phishing exercises and training and decreased in the following months; however, an increase was observed in the long term. © 2023, IGI Global. All rights reserved.
Citation - Scopus: 4
Nonuniform Currents Flowing on a Perfectly Conducting Cylinder
(2011) Başdemir, H.D.
In this paper, we applied physical theory of diffraction (PTD) method to the perfectly electric conducting (PEC) cylinder for investigation of the scattering fields. Physical optics (PO) method was used to gain the uniform scattering field which is produced by the induced current from the incident wave on the tangential plane of the perfectly electric conducting cylinder. Nonuniform current and scattered field will be obtained by applying PTD method to the problem. As a last step of solution, nonuniform currents and nonuniform scattering fields were obtained with the assistance of the exact solution of the scattering waves from the cylinder. The scattering fields and currents are plotted numerically. © 2011 IEEE.
Citation - Scopus: 4
Plagiarism Detection in Learning Management System
(Institute of Electrical and Electronics Engineers Inc., 2017) Sabonchi, A.K.S.; Görür, A.K.
Learning Management Systems has become one of the teaching tool same as the pen, pencil, blackboard, book, and notebook. Learning Management System (LMS) is defined and types that are derived from this system such as those focused only on the curriculum and those focuses on the management of the education system, and the combination of both are explained. The properties and features that must exist are identified and showed so that it can be called a learning management system. The name and the experiences of countries in terms of the use of this system as well as the benefits resulting from the user experiences have motivated schools and educational institutions to start the establishment of such systems. The main purpose of this study is, an online plagiarism detection system will be developed and integrated into Moodle so that it can be used by teachers to detect cheating and plagiarism cases in students submitted answers. © 2017 IEEE.
Citation - WoS: 15
Citation - Scopus: 20
Using Containers as Storage Facilities in Humanitarian Logistics
(Emerald Group Publishing Ltd, 2014) Sahin, Aysenur; Ertem, Mustafa Alp; Emur, Emel
Purpose - The purpose of this paper is to investigate the use of freight containers to store relief items instead of operating a permanent warehouse building. Design/methodology/approach - A mathematical model is developed to determine the location and quantity of containers as well as the type and amount of relief supplies to store in order to investigate the practicality of using freight containers for storage. The model is tested using earthquake risk data, estimates of population under risk, and the distances between cities. An experimental study is performed using Turkish Prime Ministry Disaster and Emergency Management Presidency (abbreviated as AFAD in Turkish) data for total number of relief supplies. Findings - Considering the earthquake risk of possible locations, the results of the study indicate the target locations for containers. The idea of using containers as storage facilities helped beneficiaries to be reached within a short distance and in an efficient way. Research limitations/implications - The presented model is not implemented in real life disaster relief operations even if it is tested with real earthquake risk, demand and distance data. Practical implications - To apply this model in practice, the container locations within cities should be determined and managerial operations such as maintenance, environmental, and security planning have to be considered. Originality/value - This study presents the first analysis of three sub-topics' intersection: warehousing, pre-positioning in disaster relief, and containerization. To the best of authors' knowledge, containers have not been considered for storage of relief items in humanitarian logistics before.

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