Yazar "Tutuncu, Kemal" seçeneğine göre listele

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    Adaptive LSB Steganography Based on Chaos Theory and Random Distortion
    (UNIV SUCEAVA, FAC ELECTRICAL ENG, 2018) Tutuncu, Kemal; Demirci, Baris
    Image steganography is a technique to hide secret information in an image without leaving any apparent evidence of image alteration. Hiding capacity, perceptual transparency, robustness, and resistance against attack must be considered as characteristics of the image steganography algorithms. In this study, Improved Chaos Based Bit Embedding has been proposed as a new steganography algorithm. It is based on two basic principles. One of them is determining the bits in which the secret data will be embedded by logistic map and the other one is embedding the secret data into only one of the three color channels that is chosen randomly. It distorts the other remaining channels so that it is harder to obtain the text within the image by an unwanted person. The proposed algorithm has been tested on 10 sample images along with the four basic steganography algorithms: Least Significant Bit Embedding Pseudo Random Least Significant Bit Embedding, EzStego, and F5. It has been seen that generating unpredictable indexes by the chaotic random number generators, and embedding the secret data into only one of the three channels (distorting remaining channels) increased resistance against attacks. Perceptual transparencies and capacity ratio of the proposed algorithm are compatible with the other four algorithms.
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    Analysis of ERASMUS Staff and Student Mobility Network within a Big European Project
    (IEEE, 2017) Savic, Milos; Ivanovic, Mirjana; Putnik, Zoran; Tutuncu, Kemal; Budimac, Zoran; Smrikarova, Stoyanka; Smrikarov, Angel
    The academic mobility is one of key factors that enable the globalization of research and education. In this paper we study the network of ERASMUS staff and student exchange agreements between academic institutions involved in FETCH - a big European project oriented towards future education and training in computer science. The structure of the network was investigated relying on standard metrics and techniques of social network analysis. Obtained results indicate that the network is in a mature phase of the development in which none of the institutions has a critical role to the overall connectedness of the network. Additionally, the network has a clear core-periphery structure with an active core and mostly inactive periphery.
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    Comparison of LSB Image Steganography Technique in Different Color Spaces
    (IEEE, 2017) Cataltas, Ozcan; Tutuncu, Kemal
    The incredible progress of technology has made the use of communication and information technologies indispensable because of the possibilities it offers. These possibilities increased the security issues on personal information and communication security problems such as phone calls, retrieving e-mail contents, copying private information on computers. Encryption algorithms used in classical security approaches, while ensuring the confidentiality of information, cannot provide the principle of "imprecision" that has become increasingly important in recent times. A coded or encrypted text can be solved by advanced machines when focused on it. So the key point is "do not raise suspicion". For this reason, steganography and watermarking methods that put the invisibility of the existence of a secret message into the primary goal are especially the focus of interest after 2000's years. In this study, Least Significant Bit (LSB) technique, which is the most basic and commonly used technique in steganography, was applied to 3 different images in different color spaces. When the obtained results were compared according to the image quality evaluation criteria, it has been seen that the images in Hue-Saturation-Intensity (HSI) color spaces had better performances and successes to the other color spaces.
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    Diagnosis of mesothelioma disease using different classification techniques
    (2017) Tutuncu, Kemal; Çataltaş, Özcan
    Mesothelioma, which is a disease of the pleura and peritoneum, is an asbestos-related environmental disease in undevelopedcountries. Although the incidence of this disease is lower than that of lung cancer, the reaction it creates in society is very high. In thisstudy, 9 different classification algorithms of data mining were applied to the Mesethelioma data set obtained from real patients in DicleUniversity, Faculty of Medicine and loaded into UCI Machine Learning Repository, and the results were compared. When the obtainedresults were examined, it has been seen that Artificial Neural Network (ANN) had %99.0740 correct classification ratio.
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    A fuzzy clustering approach for finding similar documents using a novel similarity measure
    (PERGAMON-ELSEVIER SCIENCE LTD, 2007) Saracoglu, Ridvan; Tutuncu, Kemal; Allahverdi, Novruz
    Searching for similar documents has a crucial role in document management. This paper aims for developing a fast and high quality method of searching similar documents based on fuzzy clustering in large document collections. In order to perform these requirements, a two layers structure is proposed. Formerly, finding the similarity in documents is based on the strategy that uses word-by-word comparison. The proposed method in this study uses two layers structure and lets the documents pass through it to find the similarities. In this system, predefined fuzzy clusters are used to extract feature vectors of related documents for finding similar documents of them. Similarity measure is estimated based on these vectors. To do this, a distance based similarity measure is proposed. It has been seen in empirical results that the proposed system uses new similarity measure and has better performance compared with conventional similarity measurement systems. (c) 2006 Elsevier Ltd. All rights reserved.
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    New approach in E-mail based text steganography
    (2015) Tutuncu, Kemal; Hassan, Abdikarim Abi
    : In this study combination of lossless compression techniques and Vigenere cipher was used in the e-mail based text steganography. It makes use of email addresses to be the keys to embed/to extract the secret message into/from the email text (cover text). After selecting the cover text that has highest repetition pattern regarding to the secret message the distance matrix was formed. The members of distance matrix were compressed by following lossless compression algorithms as in written sequence; Run Length Encoding (RLE) Burrows Wheeler Transform (BWT) Move to Front (MTF) Run Length Encoding (RLE) Arithmetic Encoding (ARI). Later on Latin Square was used to form stego key 1and then Vigenere cipher was used to increase complexity of extracting stego key 1. Final step was to choose e-mail addresses by using stego key 1 (K1) and stego key 2 (K2) to embed secret message into forward email platform. The experimental results showed that proposed method has reasonable performance in terms of capacity and also higher security in terms of complexity.