Bilgisayar Mühendisliği Bölümü Yayın Koleksiyonu

Permanent URI for this collectionhttps://hdl.handle.net/20.500.12416/253

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Mobile Assisted Language Learning: English Pronunciation at Learners' Fingertips
(Anı Yayıncılık, 2009) Saran, Murat; Seferoğlu, Gölge; Çağıltay, Kürşat
Problem Statement: The study of pronunciation had been a relatively neglected issue in the foreign/second language acquisition literature. Likewise, in classroom contexts, pronunciation has received less attention as compared to the other language components and skills with the belief that it is peripheral to successful communication. Yet, there is a recent revival of interest in pronunciation research. The literature on foreign/second language acquisition highlights that in general in-class activities are not sufficient for effective language learning and that learners should also have input and output opportunities outside the classroom. This holds true for learning pronunciation as the literature suggests that just classroom instruction has a negligible impact on oral production of learners. With their widespread use and their features such as mobility, localization, and personalization, mobile phones offer a great potential for out-of-class learning. Yet, there is scarce research on the use of mobile phones in language learning contexts nor any on using mobile phones to improve learners' pronunciation. This study is aimed to make a significant contribution to the literature in these respects. Purpose of the Study: The major aim of this study was to investigate the potentials and effectiveness of using mobile phones in foreign language education. In particular, the effects of using multimedia messages via mobile phones for improving language learners' pronunciation of words were explored. Methods: A mixed method approach involving both quantitative and qualitative components was employed in this study. The quantitative part of the study followed a pre-test/post-test quasi-experimental design. The qualitative part of the study included post-study semi-structured interviews with the students, and a questionnaire involving open ended items. The participants of this study were a group of students attending the English Preparatory School of an English-medium university in Turkey. There different groups were formed in order to investigate the comparative effectiveness of supplementary materials delivered through 3 different means: mobile phones, web pages, and handouts. Results: Analyses of the quantitative data showed that using mobile phones had positive effects on students' pronunciation learning. The qualitative data collected through the questionnaire and the interviews supported this finding. All participants provided positive feedback about the mobile learning application used in this study. Conclusions and Recommendations: This study extends the use of use mobile phones, which are already in use for communication and entertainment, to educational settings. The findings of the study pose crucial implications for foreign language teaching and learning
Büyük Veri Mahremiyeti ve Güvenliği
(Grafiker Yayınları, 2017) Saran, Ayşe Nurdan
Bilim geliştikçe teknolojiler gelişmekte ve yeni teknolojilerde bilimin daha da gelişmesine ve bilinmezleri daha iyi anlamamıza, yeni çalışmalar yapmamıza en önemlisi çevremizi ve dünyamızı daha iyi anlamamızı kolaylaştırmaktadır. Son yıllarda “büyük veri”, “veri bilimi”, “açık veri” “büyük veri analitiği”, “bilgi ekonomisi” gibi başlıklar ülkemizde de pek çok etkinlikte tartışılmakta, çözümler geliştirilmeye çalışılmakta ve iyi örnekler oluşturulmaya çalışılmaktadır. Bu kitabın ülkemizde açık veri ve büyük veri analitiği, güvenliği ve mahremiyetinin gelişmesine katkılar sağlaması beklenmektedir. Verilerin günümüzün altın rezervleri olduğunun bilinciyle çalışmalar yapılmalıdır.
Metinden Bağımsız Otomatik Konuşmacı Tanıma Sistemleri ve Performans Karşılaştırması
(2010) Taşel, Faris Serdar; Sönmez, Arzu Burçak
Otomatik Konuşmacı Tanıma Sistemleri önemli bir çalışma alanı olmakla beraber başlıca üç farklı alanda yaygın olarak kullanılmaktadır. Bunlar, kimlik doğrulama, kimlik izleme ve adli uygulamalardır. Otomatik konuşmacı tanıma uygulamaları, konuşma esnasında çıkardığımız seslerden gerekli bilgilerin çıkartılması esasına dayanmaktadır. Geliştirilen uygulamalar, çıkarılan bu bilgiler doğrultusunda, insanları seslerinden tanımaları için eğitilebilirler. Otomatik Konuşmacı Tanıma Sistemlerinde ilk basamak öznitelik çıkarma işlemidir. Bu işlem için MFCC (Mel-frequency Cepstral Coefficients) tabanlı yaklaşımlar yaygın olarak kullanılır. İkinci basamak ise öznitelik sınıflandırma işlemidir. Her konuşmacı bir sınıfa karşılık gelmekte ve bulunduğu sınıfın özelliklerini belirlemektedir. VQ (Vector Quantization - Vektörel Nicemleme) ve GMM (Gaussian Mixture Models - Gaussian Karışım Modelleri), sınıflandırma işleminde kullanılan tekniklerden en yaygın olanlarıdır. Bahsettiğimiz bu işlemler sistemin eğitim safhasında kullanılırlar. Test safhasında ise, herhangi bir kişiden gelen ses bilgisinin eğitim safhasında oluşturulan sınıflardan hangisine ait olabileceğine karar verilir. Kapalı küme sistemlerde, sistem sadece daha önce eğitilmiş konuşmacı sınıflarını ayırdetmekten sorumludur. Bu çalışma, metinden bağımsız, kapalı küme konuşmacı tanıma sistemi geliştirmede etkili olan bu iki tekniği performans açısından karşılaştırmak amacıyla yapılmıştır. Elde edilen sonuçlarda GMM tekniğinin, VQ tekniğinden daha başarılı olduğu gözlemlenmiştir.
Towards a Serious Game to Teach ISO/IEC 12207 Software Lifecycle Process: An interactive learning approach
(2015) Aydan, Ufuk; Yılmaz, Murat; O’Connor, Rory V.
ISO/IEC 12207 training is a key element to provide an ability to software development organizations for selecting a set of required processes, measuring the performance of these processes, and continuously improving them. Traditionally, such training is either performed by an expert individual to the software quality management personnel most likely in form of a seminar in a classroom environment. This may also be given by a suitability qualified professional, such as a registered auditor. However, software requirements are usually subject to change, and therefore such training is not enough to teach the substantial details of the entire standard. This has led to increased reports of complications, which demotivates organization to use this standard. To improve the quality of training, a 3D serious game was proposed for the software practitioners. The preliminary idea here is that the game employs 3D office landscape to provide a realistic virtual environment ensuring that the training will be based on real word like situations. Before building a prototype for our serious game, we consulted five industrial experts whose works are related with ISO standards. To give these practitioners an opportunity to explore the conceptual design and raise some potential problems, the semi-structured interview method was used. Based on the suggestions of experts, dynamics and mechanics of the proposed game were updated. Taken together, initial results suggest that a serious game for teaching ISO/IEC 12207 should be useful for individuals who are interested to learn more about the standard.
İmge İçine Bilgi Gizlemede Kullanılan LSB Yöntemlerinin Karşılaştırması
(2013) Saran, Nurdan; Olcay, Cem
Dijital imgeleri temel olarak kayıplı sıkı¸stırılmı¸s tipte olanlar, sıkı¸stırılmamı¸slar ve kayıpsız sıkı¸stırılmı¸slar olarak ¨u¸ce ayırabiliriz. Sıkı¸stırılmamı¸s ve kayıpsız sıkı¸stırılmı¸s imgelerde bilgi gizlemek i¸cin en ¸cok kullanılan y¨ontem, imgenin son bitlerinin mesajın bitleri ile de˘gi¸stirilmesi y¨ontemidir. Son bitlerin de˘gi¸simi genellikle imgede g¨ozle g¨or¨ulebilir bir de˘gi¸sikli˘ge sebep olmamaktadır. Ort¨u imgedeki piksellerin son bitlerinin de˘gi¸simi ile ¨ veri gizleme y¨ontemlerini her renk kanalında 1 bit yada daha fazla veri gizleyenler ve birden ¸cok renk kanalında renk kanalı sayısından daha az miktarda veri gizleyenler olarak ikiye ayırabiliriz. Bu ¸calı¸smada en ¨onemsiz bite (least significant bit-LSB) gizleme y¨ontemlerinden yer de˘gi¸stirme [1], e¸sle¸stirme [2], e¸sle¸stirmenin geli¸stirilmi¸s bir hali olan Chan’ın algoritması [3], 2/3 verimli g¨omme [4], Hamming kodlarını kullanılarak
Cassandra ve MongoDB NoSQL Veri Tabanlarının Karşılaştırmalı Güvenlik Analizi
(2019) Saran, Murat; Saran, Nurdan
In this study, we analyze the security of two NoSQL databases, MongoDB 3.6.3 and Cassandra 3.11.1 in a multi-node configuration in two steps. The first step is a comparative study of both databases’ security features according to ten selected criteria from the literature. The second step is analyzing data encryption overhead using the Yahoo Cloud Serving Benchmark tool. This study will help decision-makers and researchers to realize the most crucial security features concerning NoSQL databases as well as to be able to analyze the NoSQL databases regarding the security features. Our security comparison results show that both databases have noteworthy security features. However, Cassandra takes the lead as it supports more security criteria. Besides, the encryption/decryption performance of the MongoDB business version is 53% faster than the Cassandra business version, and the average amount of data that the MongoDB business version can process per minute is 45% higher than the Cassandra business version. This result shows that it is more appropriate to use MongoDB in environments where encryption is required.
Production and retrieval off rough classes in multi relations
(IEEE Computer Soc, 2007) Tolun, Mehmet R.; Sever, Hayri; Görür, Abdül Kadir
Organizational memory in today's business world forms basis for organizational learning, which is the ability of an organization to gain insight and understanding from experience through experimentation, observation, analysis, and a willingness to examine both successes and failures. This basically requires consideration of different aspects of knowledge that may reside on top of a conventional information management system. Of them, representation, retrieval and production issues of meta patterns constitute to the main theme of this article. Particularly we are interested in a formal approach to handle rough concepts. We utilize rough classifiers to propose a preliminary framework based on minimal term sets with p-norms to extract meta patterns. We describe a relational rule induction approach, which is called rila. Experimental results are provided on the mutagenesis, and the KDD Cup 2001 genes data sets.
Clustering Analysis for Vasculitic Diseases
(Springer-Verlag Berlin, 2010) Yıldırım, Pınar; Çeken, Çınar; Çeken, Kağan; Tolun, Mehmet R.
We introduce knowledge discovery for vasculitic diseases in this paper. Vasculitic diseases affect some organs and tissues and diagnosing can be quite difficult. Biomedical literature can contain hidden and useful knowledge for biomedical research and we develop a study based on co-occurrence analysis by using the articles in MEDLINE which is a widely used database. The mostly seen vasculitic diseases are selected to explore hidden patterns. We select PolySearch system as a web based biomedical text mining tool to find organs and tissues in the articles and create two separate datasets with their frequencies for each disease. After forming these datasets, we apply hierarchical clustering analysis to find similarities between the diseases. Clustering analysis reveals some similarities between diseases. We think that the results of clustered diseases positively affect on the medical research of vasculitic diseases especially during the diagnosis and certain similarities can provide different views to medical specialists.
Structural stability and energetics of single-walled carbon nanotubes under uniaxial strain
(2003) Dereli, G.; Özdoğan, Cem
A (10x10) single-walled carbon nanotube consisting of 400 atoms with 20 layers is simulated under tensile loading using our developed O(N) parallel tight-binding molecular-dynamics algorithms. It is observed that the simulated carbon nanotube is able to carry the strain up to 122% of the relaxed tube length in elongation and up to 93% for compression. Young's modulus, tensile strength, and the Poisson ratio are calculated and the values found are 0.311 TPa, 4.92 GPa, and 0.287, respectively. The stress-strain curve is obtained. The elastic limit is observed at a strain rate of 0.09 while the breaking point is at 0.23. The frequency of vibration for the pristine (10x10) carbon nanotube in the radial direction is 4.71x10(3) GHz and it is sensitive to the strain rate.
Perceptions, Expectations and Implementations of Big Data in Public Sector
(2018) Doğdu, Erdoğan; Özbayoğlu, Murat; Yazıcı, Ali; Karakaya, Ziya
Big Data is one of the most commonly encountered buzzwords among IT professionals nowadays. Technological advancements in data acquisition, storage, telecommunications, embedded systems and sensor technologies resulted in huge inflows of streaming data coming from variety of sources, ranging from financial streaming data to social media tweets, or wearable health gadgets to drone flight logs. The processing and analysis of such data is a difficult task, but as appointed by many IT experts, it is crucial to have a Big Data Implementation plan in today’s challenging industry standards. In this study, we performed a survey among IT professionals working in the public sector and tried to address some of their implementation issues and their perception of Big Data today and their expectations about how the industry will evolve. The results indicate that most of the public sector professionals are aware of the current Big Data requirements, embrace the Big Data challenge and are optimistic about the future.
Multimodal interaction flow representation for ubiquitous environments - MIF: A case study in surgical navigation interface design
(2015) Tokdemir, Gül; Altun, Gamze; Çağıltay, Nergiz E.; Maras, H. Hakan; Börcek, Alp Özgün
With the advent of technology, new interaction modalities became available which augmented the system interaction. Even though there are vast amount of applications for the ubiquitous devices like mobile agents, smart glasses and wearable technologies, many of them are hardly preferred by users. The success of those systems is highly dependent on the quality of the interaction design. Moreover, domain specific applications developed for these ubiquitous devices involve detailed domain knowledge which normally IT professionals do not have, which may involve a substantial lack of quality in the services provided. Hence, effective and high quality domain specific applications developed for these ubiquitous devices require significant collaboration of domain experts and IT professionals during the development process. Accordingly, tools to provide common communication medium between domain experts and IT professionals would provide necessary medium for communication. In this study, a new modelling tool for interaction design of ubiquitous devices like mobile agents, wearable devices is proposed which includes different interaction modalities. In order to better understand the effectiveness of this newly proposed design tool, an experimental study is conducted with 11 undergraduate students (novices) and 15 graduate students (experienced) of Computer Engineering Department for evaluating defect detection performance for the defects seeded into the interface design of a neuronavigation device. Results show that the defects were realized as more difficult for the novices and their performance was lower compared to experienced ones. Considering the defect types, wrong information and wrong button type of defects were recognized as more difficult. The results of this study aimed to provide insights for the system designers to better represent the interaction design details and to improve the communication level of IT professionals and the domain experts. © Springer International Publishing Switzerland 2015.
Kitlesel Açık Çevrimiçi Kurslardaki Katılımcı Profillerinin Yapay Sinir Ağı Kullanılarak Sınıflandırılması
(2015) Al-Taei, Ali; Yılmaz, Murat; O’Connor, Rory V.; Halıcı, Uğur
Son yıllarda, özellikle bilgisayar mühendisliği eğitimi alanında, kitlesel açık çevrimiçi kurslara (KAÇK) artan bir ilgi söz konusudur. Bu ilgi bireylerin davranışları, özellikleri ve tercihlerinin anlaşılması öneminin altını çizmektedir. Böyle bir anlayış geliştirmek, sıklıkla oyun geliştirme alanında kullanılan kişilik profilleme gibi yenilikçi teknikleri uyarlayarak KAÇK tasarım sürecini geliştirmek için çeşitli yollar gerektirmektedir. Bu çalışma, bir kişilik referansı olarak Myers-Briggs Tip Göstergesi (MBTG) kullanılarak katılımcıları (özellikle eksik veri durumlarında) sınıflandırmak için bir yöntem önermektedir. Amaç, KAÇK izleyicileri hakkında ayrıştırıcı bir bakış sunmak için KAÇK katılımcı profillerini MBTG kullanarak araştırmaktır. Bu amaçla, bir bilgisayar mühendisliği kursunda 20 soruluk bir çevrimiçi anket kullanılmıştır: Muhatapların (N=75) cevapları yardımıyla katılımcıların kişilik tipleri belirlenmiştir. Dahası, bir makine öğrenimi modeli bireylerin sınıflandırması için önerilmiştir. Sonuçlar, geri yayılımlı (GY) yapay sinir ağının hem eğitim süreci (performans=%100) hem de test süreci için (performans=%93,3) uygun olduğunu göstermiştir. Bu bilgilerin ışığında, yaklaşımımızın MBTG açısından KAÇK katılımcılarının sınıflandırılabilirliklerini araştırmak için kullanılabilecek özgün bir yaklaşım olarak kabul edilebilir.
Futbol hakemlerinin karar verme yeteneklerini Geliştirmek için Düşünülmüş Ciddi Oyun Tabanlı Öğrenme Çatısı
(2015) Güleç, Ulaş; Yılmaz, Murat
Surface modification by 1 keV ion impact: molecular dynamics study of an Ar+-Ni(100) collision system
(2008) Özdoğan, Cem; Atis, Murat; Güvenç, Ziya B.
An Ar+-Ni(1 0 0) collision system at 1 keV impact energy was investigated by using realistic isoenergetic molecular dynamics (MD) simulations. The sputtering process upon Ar+ ion impact and damage to the Ni(1 0 0) surface are examined in detail. Studying of high bombarding energy regions leads to the necessity of larger and thick enough slabs, otherwise incoming ions can easily pass through the slab; as a result, investigated physical properties may not be revealed. In addition the simulation time should be long enough to observe and to calculate a reliable macroscopic property such as sputtering yield that is addressed in this study. In order to preserve the total energy in the simulation at this collision energy a small time-step (0.1 fs) is used. We have made use of our developed linear scaling parallel MD program to overcome these demands. The Ni(1 0 0) slab is formed by 63700 atoms (122 angstrom x 122 angstrom x 44 angstrom) and the total observation time for each collision event is about 2.25 ps. Several properties such as penetration depths, angular and energy distributions of the reflected Ar and sputtered Ni atoms as well as dissociation time, embedded, scattering, sputtering patterns and geometries of the sputtered clusters are also reported, and the calculated sputtering yield is found to be in good agreement with the available experimental results.
Software Development Roles: A Multi-Project Empirical Investigation
(2015) Yılmaz, Murat; O'Connor, Rory V.; Clarke, Paul
In our earlier research work, we developed a conceptual framework that identifies the di?erent types of roles that can exist in contemporary software development projects (including both agile and traditional software development approaches). The purpose of the framework is to assist software project managers when tuning software development project roles to the demands of individual projects, with our previous research indicating that there is a need to tailor software development roles to individual projects. In this work, we extend the earlier research through the use of a series of semi-structured interviews within seven Turkish software companies. The results, which are consistent with previous findings, offer further evidence of the usefulness of the framework, while also identifying possible areas for future work in this space.
Integration between Cryptography and Steganography to Hide Secret Message inside an Image
(2017) Nashaat, Ahmed; Tarıyan, Sibel
The information hiding is progression of hiding the details of a function or object or both of them. On the other hand it represents an important way that used in data security. Another name for information hiding is the steganography, which hides the data inside another data such as embed text inside image or image inside another one. The steganography techniques were used from ancient times and through uses of many mechanics and different ways, such as writing in invisible ink in the Greek Testament, while Cryptography is the process of hiding information by encrypt this data using a complex algorithms. Cryptography is used when collaborating over an untrusted intermediate such as internet. The steganography and cryptography work similarly but in different contexts. In this study, an integration of cryptography and steganography to produce an efficient and robust model has been presented. In terms of cryptography, the Data Encryption Standard (DES) algorithm is implemented, whereas in steganography, the Least Significant Bit (LSB) algorithm is used. Our results show efficient time implementation and a robust algorithm mechanism in terms of peak signal-to-noise ratio (PSNR), signal-to-noise ratio (SNR) and mean square error (MSE).
Residual Lsf Vector Quantization Using Arma Prediction
(2016) Özaydın, Selma
The residual LSF vector quantization yields bit rate reduction in the vocoders. In this work, a residual LSF vector quantization obtained from Auto Regressive Moving Average (ARMA) prediction is proposed for designing codebooks at very low bit rates. This residual quantization method is applied to multi stage vector quantization method and codebooks are designed. For each codebook, the effectiveness and quality are investigated by calculating the spectral distortion and outliers. The proposed quantization method reduced the distortion without any additional complexity.
Variability Incorporated Simultaneous Decomposition of Models under Structural and Procedural Views
(CRC Press, 2019) Kaya, M. Çağrı; Tokdemir, Gül; Suloğlu, Selma; Tekinerdoğan, Metin
This chapter presents hierarchical variability as an important development notion especially when considered together with a systems specification through decomposition. A matured domain-specific environment is the precondition for variability-centric engineering for compositional approaches as targeted in this study: Most of the requirements have been already modeled, and most of the problem domain elements have corresponding reusable solutions. Also, a mature domain enjoys a wide community of developers who are familiar with those problems and solution-space elements and an effective set of specific tools. Decomposition is a fundamental mechanism in many approaches for the specification of various dimensions of modeling. Decomposition of especially structure modeling for software is not new. Here, variability guidance is incorporated into both structure and process decomposition. This chapter combines such notions in the demonstration of variabilitycentric development suggesting a structural and procedural decomposition of the system. The predecessors, component-oriented approaches rely on the structural decomposition whereas service-oriented development is being supported by process decomposition. A vending machine case study is presented in this chapter for demonstrating the propagation of variability specification along with the enhancements of the componentoriented model and the process model.
Low-diameter topic-based pub/sub overlay Network Construction with minimum–maximum node Degree
(2021) Yumusak, Semih; Layazali, Sina; Öztoprak, Kasım; Hassanpour, Reza
In the construction of effective and scalable overlay networks, publish/subscribe (pub/sub) network designers prefer to keep the diameter and maximum node degree of the network low. However, existing algorithms are not capable of simultaneously decreasing the maximum node degree and the network diameter. To address this issue in an overlay network with various topics, we present herein a heuristic algorithm, called the constant-diameter minimum–maximum degree (CD-MAX), which decreases the maximum node degree and maintains the diameter of the overlay network at two as the highest. The proposed algorithm based on the greedy merge algorithm selects the node with the minimum number of neighbors. The output of the CD-MAX algorithm is enhanced by applying a refinement stage through the CD-MAX-Ref algorithm, which further improves the maximum node degrees. The numerical results of the algorithm simulation indicate that the CD-MAX and CD-MAX-Ref algorithms improve the maximum node-degree by up to 64% and run up to four times faster than similar algorithms.
Hough Dönüşümünün Dairesel Şekil Tespiti İçin CUDA Üzerinde Paralelleştirilmesi
(2012) Tasel, Serdar Faris
Hough Dönüşümü, görüntü işlemede çizgi, daire ve elips gibi şekillerin tespitinde kullanılan iyi bilinen bir tekniktir. Hough Dönüşümü başarılı bir teknik olmasına rağmen, yüksek miktarda hesaplama ve bellek ihtiyaçlarından dolayı bu tekniğin uygulanmasında güçlük çekilmektedir. Bu tür tekniklerin Grafik İşlem Birimi (GPU) üzerinde Birleşik Hesaplama Aygıtı Mimarisi (CUDA – Compute Unified Device Architecture) kullanılarak paralelleştirilmesi son zamanlarda önem kazanmıştır. Bu makalede, standart Hough Dönüşümü yaklaşımları ve CUDA kullanılarak dairesel şekil tespiti için özelleştirimiş Hough Dönüşümü stratejileri sunulmuştur. Yapılan deneyler, CUDA üzerinde dairesel şekil tespiti için özelleşmiş Hough Dönüşümünün paralelleştirilmesinin, algoritma performansını yaklaşık 360 kata kadar hızlandırdığını göstermektedir. Deneylerde kullanılan programın kaynak kodlarına aşağıdaki adresten erişilebilir: http://academic.cankaya.edu.tr/~fst/cuda/htcircles.html

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Browsing Bilgisayar Mühendisliği Bölümü Yayın Koleksiyonu by Department "Çankaya Üniversitesi, Mühendislik Fakültesi, Bilgisayar Mühendisliği Bölümü"