Yazılım Mühendisliği Bölümü

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Citation Count: Choupani, Roya; Tolun, Mehmet R. (2005). "Hand gesture recognition in variable length sequences", WSEAS Transactions on Information Science and Applications, Vol. 2, No. 9, pp. 1294-1301.
Hand gesture recognition in variable length sequences
(2005) Choupani, Roya; Tolun, Mehmet R.; 1863
Using hand gestures in human computer interaction has been a major challenge during the recent years. Many of the hand gesture recognition systems however, have been based on the recognition of hand postures and estimating the related gesture which is restricted to a few numbers of possible movements. However when dealing with applications such as understanding sign languages which include a large number of classes, an automatic learning method based on matching a sequence of postures with the characterizing feature sequence of each class is necessary. An important characteristic of this method is that each sample sequence of a class may have a variable length and different position of the key features. In this paper a syntactic method has been proposed for classifying the input sequences. An algorithm foe extracting the grammar of the method during training stage is also given.
Citation Count: Choupani, Roya; Tolun, Mehmet R. (2006). "Recent challenges in video coding and streaming", International Conference on Signals and Electronic Systems, ICSES'0617 September 2006through 20 September 2006, pp. 157-160.
Recent challenges in video coding and streaming
(2006) Choupani, Roya; Tolun, Mehmet R.; 1863
Video streaming over the Internet has gained popularity during the recent years which is mainly the result of the introduction of video-conferencing and videotelephony. These in turn have made it possible to bring to life many applications such as transmitting video over the Internet and telephone lines, surveillance and monitoring, telemedicine (medical consultation and diagnosis at a distance), and computer based training and education. These applications need a large bandwidth which is not available in all cases. Many video encoding standards have been introduced to deal with video compression and transmission problems. In this study, we have discussed the main technical features of the most important video coding standards in a comparative approach. The appropriateness of these features is application and transmission environment dependant. Manipulating video stream features or video transcoding methods are discussed as well.
Citation Count: Altunel, Yusuf; Tolun, Mehmet R.; Sobh, T. (2008). "Component-Based Project Estimation Issues for Recursive Development", Advances in Computer and Informatiom Sciences and Engineering, pp. 577-+.
Component-Based Project Estimation Issues for Recursive Development
(2008) Altunel, Yusuf; Tolun, Mehmet R.; Sobh, T.; 1863
In this paper we investigated the component-based specific issues that might affect project cost estimation. Component-based software development changes the style of software production. With component-based approach the software is developed as the composition of reusable software components. Each component production process must be treated as a stand-alone software project, which needs individual task of management. A typical pure component-based development can be considered as decomposition/integration activities successively applied at different levels and therefore results in recursive style of development. We analyzed and presented our results of studies on the component-based software development estimation issues from recursive point of view.
Citation Count: Choupani, Roya; Wong, Stephan; Tolun, Mehmet R. "Multiple Description Scalable Coding for Video Transmission over Unreliable Networks", Embedded Computer Systems: Architectures, Modeling, and Simulation, pp. 58-67, 2009.
Multiple Description Scalable Coding for Video Transmission over Unreliable Networks
(2009) Choupani, Roya; Wong, Stephan; Tolun, Mehmet R.; 1863
Developing real time multimedia applications for best effort networks such as the Internet requires prohibitions against jitter delay and frame loss. This problem is further complicated in wireless networks as the rate of frame corruption or loss is higher in wireless networks while they generally have lower data rates compared to wired networks. On the other hand, variations of the bandwidth and the receiving device characteristics require data rate adaptation capability of the coding method. Multiple Description Coding (MDC) methods are used to solve the jitter delay and frame loss problems by making the transmitted data more error resilient, however, this results in reduced data rate because of the added overhead. MDC methods do not address the bandwidth variation and receiver characteristics differences. In this paper a new method based on integrating MDC and the scalable video coding extension of H.264 standard is proposed. Our method can handle both jitter delay and frame loss, and data rate adaptation problems. Our method utilizes motion compensating scheme and, therefore, is compatible with the current video coding standards such as MPEG-4 and H.264. Based on the simulated network conditions, our method shows promising results and we have achieved up to 36dB for average Y-PSNR.
Citation Count: Medeni, İ.T.; Aktaş, Z.A.; Tolun, M.R. "Bilgi Biliminin Mühendislik Gereksinimi ve Bilgi Mühendisliği", Elektrik Elektronik Bilgisayar Biomedikal Mühendisleri Eğitimi 4. Ulusal Sempozyumu, 2009.
Bilgi Biliminin Mühendislik Gereksinimi ve Bilgi Mühendisliği
(2009) Medeni, İhsan Tolga; Aktaş, A. Ziya; Tolun, Mehmet R.; 1863
Yirminci yüzyılın ikinci yarısında bilgisayar, bilgi ve iletişim teknolojilerindeki gelişmeler bilgiye dayalı yeni bilim ve mühendislik disiplinleri oluşturma ihtiyacını doğurmuştur. Bu ihtiyaç nedeniyle doğan yeni bilim ve mühendislik disiplinlerinin gelişiminin aslında (veri, enformasyon ve bilgi ) üçlüsüne yönelik oluşumlar olduğu gözlemlenmektedir.Bu makalede bilgi sözcüğü bu üçlü için genel bir ad olarak kullanılacaktır. Bilgi disiplini bir taraftan, bu üçlü arasındaki bağların örgütler ve bireyler açısından ortaya koyulmasını amaçlar; açık ve örtük bilginin birbirine dönüşümünü sağlamaya çalışırken, diğer taraftan da ortaya çıkan yeni dallar ve var olan dalların bilgi temelli ilişkisini kurmaya yönelik çalışmalar yapmaktadır. Bu üçlünün ve bilgi disiplininin bilim / mühendislik, işletme / yönetim disiplinleriyle olan ilişkisi ve oluşturulacak bir bilgi mühendisliği lisans programının bu kavramlarla olabilecek ilgisi bu bildirinin konusudur.
Citation Count: Akba, Fırat...et al. "Yeşil BHT Bilgi ve Haberleşme Teknolojileri Akademisyen ve Uygulayıcılar Açısından Bir İnceleme", 4. Mühendislik ve Teknoloji Sempozyumu, 2011.
Yeşil BHT Bilgi ve Haberleşme Teknolojileri Akademisyen ve Uygulayıcılar Açısından Bir İnceleme
(2011) Akba, Fırat; Medeni, İhsan Tolga; Medeni, Tunç Durmuş; Tolun, Mehmet Reşit; Öztürk, Mehmet; 181215
Citation Count: Medeni, İhsan Tolga; Medeni, Tunç; Tolun, M. (2011). "Tacıt Knowledge Vısualızatıon Through Organızatıonal Explıcıt Knowledge Warehouses: A Proposal For Research Methodology Desıgn And Executıon", International Journal of eBusiness and eGovernment Studies, Vol.3, No.2, pp.91-100.
Tacıt Knowledge Vısualızatıon Through Organızatıonal Explıcıt Knowledge Warehouses: A Proposal For Research Methodology Desıgn And Executıon
(2011) Medeni, İhsan Tolga; Medeni, Tunç; Tolun, Mehmet
Knowledge visualization can be used in several fields from medical imaging to industrial engineering. Although there could be variety of applicable research areas, our consideration will be the tacit knowledge visualization in organizations. This proposal aims to suggest a study to develop a tacit knowledge visualization framework to support know-where requirements of the organizational knowledge. With the implementation of our framework in a software application, it is aimed to create a virtual environment, where subject-based knowledge requirements will be answered by the visualized tacit knowledge of individuals and possibly the relations among individual members of the organization
Citation Count: Choupany, Roya; Wong, Stephan; Tolun, Mehmet (2011). "Scalable video transmission over unreliable networks using multiple description wavelet coding", 7th International Conference on Digital Content, Multimedia Technology and Its Applications, IDCTA 201116 August 2011through 18 August 2011, pp. 5-10.
Scalable video transmission over unreliable networks using multiple description wavelet coding
(2011) Choupany, Roya; Wong, Stephan; Tolun, Mehmet; 1863
Scalable video coding (SVC) and multiple description coding (MDC) are the two different adaptation schemes for video transmission over heterogenous and best-effort networks such as the Internet. We present a new approach to combine the advantages of SVC and MDC to provide reliable video communication over a wider range of communication networks and/or satisfy application requirements. Our proposed method utilizes 3D discrete wavelet transform and a modified embedded zero tree data structure to group the coefficients in different descriptions. The proposed method reduces the impact of the drift error by organizing the frames in a hierarchical structure.
Citation Count: Choupani, Roya; Wong, Stephan; Tolun, Mehmet (2013). "Optimized Multiple Description Coding for Temporal Video Scalability", Advances in Intelligent Systems and Computing, Vol. 225, No. 1, pp. 167-176.
Optimized Multiple Description Coding for Temporal Video Scalability
(2013) Choupani, Roya; Wong, Stephan; Tolun, Mehmet
The vast application of video streaming over the Internet requires video adaptation to the fluctuations of the available bandwidth, and the rendering capabilities of the receiver device. On the other hand, the available video coding standards are designed for optimum bit rate which makes them susceptible to packet losses. A combination of video adaptation methods and error resilient methods can make the video stream more robust against networking problems. In this paper, an optimization for combining scalable video coding with multiple description coding schemes have been proposed. Our proposed method is capable of creating balanced descriptions with optimum coding efficiency.
Citation Count: Jafari, Aref...et al. (2014). "A combined spatial and frequency based texture model for organsegmentation in computed tomography examinations" Journal Of Medical Imaging And Health Informatics, Vol.4, No.2, pp.230-236.
A combined spatial and frequency based texture model for organsegmentation in computed tomography examinations
(Amer Scientific Publishers, 2014) Jafari, Aref; Hassanpour, Reza; Shahbahrami, Asadollah; Wong, Stephan
The organ segmentation in computed tomography (CT) examination is a tedious and error prone task. The local similarity of the pixels from different organs, and the differences between the pixels of the same organ observed in different examinations are two most challenging problems affecting the segmentation process. In this study, statistical and spectral texture properties are combined with the a-priori knowledge about the human body to develop a model for reliably segmenting organs in CT examinations. The main goal of the developed model is fusing local and global statistics to support spatial-frequency analysis and to maximize the simultaneous localization of energy in both spatial and frequency domains. The feature space dimension is reduced by means of a wrapper technique applied as a pre-processing filter. The proposed classifier utilizes a linear combination (ensemble) of two support vector machines (SVM) where the first SVM classifies the input samples according to their textural information and the second one correct the results of the first classifier by searching the spatial information of those samples in a statistical atlas.
Citation Count: Hassanpour, Reza, "A Two-Stage Matching Method for Multi-Component Shapes", Advances in Electrical and Computer Engineering, 15, No. 1, pp. 143-150, (2013).
A Two-Stage Matching Method for Multi-Component Shapes
(Univ Suceava, 2015) Hassanpour, Reza
In this paper a shape matching algorithm for multiple component objects has been proposed which aims at matching shapes by a two-stage method. The first stage extracts the similarity features of each component using a generic shape representation model. The first stage of our shape matching method normalizes the components for orientation and scaling, and neglects minor deformations. In the second stage, the extracted similarity features of the components are combined with their relative spatial characteristics for shape matching. Some important application areas for the proposed multi-component shape matching are medical image registration, content based medical image retrieval systems, and matching articulated objects which rely on the a-priori information of the model being searched. In these applications, salient features such as vertebrae or rib cage bones can be easily segmented and used. These features however, show differences from person to person on one hand and similarities at different cross-sectional images of the same examination on the other hand. The proposed method has been tested on articulated objects, and reliable registration of 3-dimensional abdominal computed tomography images.
Citation Count: Choupani, Roya; Wong, Stephan; Tolun, Mehmet. "Hierarchical SNR Scalable Video Coding with Adaptive Quantization for Reduced Drift Error", 10th International Conference on Computer Vision Theory and Applications, pp. 117-123, 2015.
Hierarchical SNR Scalable Video Coding with Adaptive Quantization for Reduced Drift Error
(2015) Choupani, Roya; Wong, Stephan; Tolun, Mehmet
In video coding, dependencies between frames are being exploited to achieve compression by only coding the differences. This dependency can potentially lead to decoding inaccuracies when there is a communication error, or a deliberate quality reduction due to reduced network or receiver capabilities. The dependency can start at the reference frame and progress through a chain of dependent frames within a group of pictures (GOP) resulting in the so-called drift error. Scalable video coding schemes should deal with such drift errors while maximizing the delivered video quality. In this paper, we present a multi-layer hierarchical structure for scalable video coding capable of reducing the drift error. Moreover, we propose an optimization to adaptively determine the quantization step size for the base and enhancement layers. In addition, we address the trade-off between the drift error and the coding efficiency. The improvements in terms of average PSNR values when one frame in a GOP is lost are 3.70(dB) when only the base layer is delivered, and 4.78(dB) when both the base and the enhancement layers are delivered. The improvements in presence of burst errors are 3.52(dB) when only the base layer is delivered, and 4.50(dB) when both base and enhancement layers are delivered.
Citation Count: A Comparative Evaluation of Popular Search Engınes On Finding Turkish Documents For A Specific Time Period (2017). Bitirim, Yiltan; Gorur, Abdul Kadir, Tehnicki Vjesnik-Technical Gazette, 24(2), 565-569.
A Comparative Evaluation Of Popular Search Engines On Finding Turkish Documents For A Specific Time Period
(Univ Osijek, Tech Fac, 2017) Bitirim, Yıltan; Görür, Abdül Kadir; 107251
This study evaluates the popular search engines, Google, Yahoo, Bing, and Ask, on finding Turkish documents by comparing their current performances with their performances measured six years ago. Furthermore, the study reveals the current information retrieval effectiveness of the search engines. First of all, the Turkish queries were run on the search engines separately. Each retrieved document was classified and precision ratios were calculated at various cut-off points for each query and engine pair. Afterwards, these ratios were compared with the six years ago ratios for the evaluations. Besides the descriptive statistics, Mann-Whitney U and Kruskal-Wallis H statistical tests were used in order to find out statistically significant differences. All search engines, except Google, have better performance today. Bing has the most increased performance compared to six years ago. Nowadays: Yahoo has the highest mean precision ratios at various cut-off points; all search engines have their highest mean precision ratios at cut-off point 5; dead links were encountered in Google, Bing, and Ask; and repeated documents were encountered in Google and Yahoo.
Citation Count: Clarke, Paul; O'Connor, Rory, V; Yilmaz, Murat, "In Search of the Origins and Enduring Impact of Agile Software Development", Proceedıngs Of The 2018 Internatıonal Conference On Software And System Process (Icssp 2018), (2018), pp. 142-146.
In Search of the Origins and Enduring Impact of Agile Software Development
(Assoc Computing Machinery, 2018) Clarke, Paul; O'Connor, Rory V.; Yılmaz,Murat; 55248
The Agile Manifesto is a philosophical touchpoint for all agile software development (ASD) methods. We examine the manifesto and certain agile methods in an effort to identify the major impacts of ASD. We have encountered some difficulty in delineating agile and non-agile software processes, which is partially the result of terminological confusion. It is clear from the volume of published research that ASD has made a significant contribution, and we have identified two lasting impacts: a reduction in iteration durations and a push for reduced levels of documentation. We find that the contemporary use of tooling to automate processes may not be wholly congruent with the manifesto and that many organisations may still rely on business contracts despite calls in the manifesto for greater levels of informal customer collaboration.
Citation Count: Çağıltay, Nergiz. "Türk Beyin Cerrahlarının Teknolojiye Ulaşım İmkanları", Türk Nöröşirurji Derneği 30. Bilimsel Kongresi, 2018.
Türk Beyin Cerrahlarının Teknolojiye Ulaşım İmkanları
(2018) Çağıltay, Nergiz; 113411
Citation Count: Par, Öznur Esra; Akçapınar Sezer, Ebru; Sever, Hayri. "Sınıflandırmada Küçük ve Dengesiz Veri Kümesi Problemi/Small and Unbalanced Data Set Problem in Classification, IEEE 27th Signal Processing and Communications Applications Conference (SIU), 2019.
Sınıflandırmada Küçük ve Dengesiz Veri Kümesi Problemi
(2019) Par, Öznur Esra; Akçapınar Sezer, Ebru; Sever, Hayri; 11916
Verilerinin sınıflandırılması, veri kümesinin küçük ve dengesiz olması durumunda zorlaşmakta ve sınıflama performansını direkt etkilemektedir. Veri setinin küçük olması ve/veya sınıflar arasında dengesizlik olması veri madenciliğinde büyük bir sorun haline gelmiştir. Sınıflama algoritmaları, veri setlerinin yeterli büyüklüğe sahip, dengeli olduğu varsayımı üzerine geliştirilmiştir. Bu algoritmaların çoğu, azınlık sınıfındaki örnekleri göz ardı ederken veya yanlış sınıflandırırken, çoğunluk sınıfa odaklanır. Medikal veri madenciliğinde bazı kısıtlardan dolayı küçük ve dengesiz veri seti problemi ile sıklıkla karşılaşılmaktadır. Çalışma kapsamında erişime açık hepatit veri seti, küçük veri setlerine bölünmüş, oluşturulan her bir veri seti uzaklık tabanlı yöntemlerle çoğaltılmıştır. Çoğaltılan veri setleri dört farklı makine öğrenmesi algoritması (Yapay Sinir Ağları, Destek Vektör Makineleri, Naive Bayes ve Karar Ağacı) kullanılarak sınıflandırılmış, elde edilen sınıflama sonuçları karşılaştırılmıştır.
Citation Count: Oyucu, Saadin; Sever, Hayri; Polat, Hüseyin (2019). "Otomatik Konuşma Tanımaya Genel Bakış, Yaklaşımlar ve Zorluklar: Türkçe Konuşma Tanımanın Gelecekteki Yolu", Gazi Üniversitesi Fen Bilimleri Dergisi Part C: Tasarım ve Teknoloji, Vol. 7, No. 4, pp. 834-854.
Otomatik Konuşma Tanımaya Genel Bakış, Yaklaşımlar ve Zorluklar: Türkçe Konuşma Tanımanın Gelecekteki Yolu
(2019) Oyucu, Saadin; Sever, Hayri; Polat, Hüseyin; 11916
İnsanlar arasındaki en önemli iletişim yöntemi olan konuşmanın, bilgisayarlar tarafından tanınması önemli bir çalışma alanıdır. Bu araştırma alanında farklı diller temel alınarak birçok çalışma gerçekleştirilmiştir. Literatürdeki çalışmalar konuşma tanıma teknolojilerinin başarımının artmasında önemli rol oynamıştır. Bu çalışmada konuşma tanıma ile ilgili bir literatür taraması sunulmuş ve farklı dillerde bu araştırma alanında kaydedilen ilerlemeler tartışılmıştır. Konuşma tanıma sistemlerinde kullanılan veri setleri, özellik çıkarma yaklaşımları, konuşma tanıma yöntemleri ve performans değerlendirme ölçütleri incelenerek konuşma tanımanın gelişimi ve bu alandaki zorluklara odaklanılmıştır. Konuşma tanıma alanında son zamanlarda yapılan çalışmaların olumsuz koşullara (çevre gürültüsü, konuşmacıda ve dilde değişkenlik) karşı çok daha güçlü yöntemler geliştirmeye odaklandığı izlenmiştir. Bu nedenle araştırma alanı olarak genişleyen olumsuz koşullardaki konuşma tanıma ile ilgili yakın geçmişteki gelişmelere yönelik genel bir bakış açısı sunulmuştur. Böylelikle olumsuz koşullar altında gerçekleştirilen konuşma tanımadaki tıkanıklık ve zorlukları aşabilmek için kullanılabilecek yöntemleri seçmede yardımcı olunması amaçlanmıştır. Ayrıca Türkçe konuşma tanımada kullanılan ve iyi bilinen yöntemler karşılaştırılmıştır. Türkçe konuşma tanımanın zorluğu ve bu zorlukların üstesinden gelebilmek için kullanılabilecek uygun yöntemler irdelenmiştir. Buna bağlı olarak da Türkçe konuşma tanımanın gelecekteki rotasına ilişkin bir değerlendirme ortaya konulmuştur.
Citation Count: Bugday, Ahmet...et al. (2019). "Creating consensus group using online learning based reputation in blockchain networks", Pervasive and Mobile Computing, Vol. 59.
Creating consensus group using online learning based reputation in blockchain networks
(Elsevier, 2019) Buğday, Ahmet; Özsoy, Adnan; Öztaner, Serdar Murat; Sever, Hayri; 11916
One of the biggest challenges to blockchain technology is the scalability problem. The choice of consensus algorithm is critical to the practical solution of the scalability problem. To increase scalability, Byzantine Fault Tolerance (BFT) based methods have been most widely applied. This study proposes a new model instead of Proof of Work (PoW) for forming the consensus group that allows the use of BFT based methods in the public blockchain network. The proposed model uses the adaptive hedge method, which is a decision-theoretic online learning algorithm (Qi et al., 2016). The reputation value is calculated for the nodes that want to participate in the consensus committee, and nodes with high reputation values are selected for the consensus committee to reduce the chances of the nodes in the consensus committee being harmful. Since the study focuses on the formation of the consensus group, a simulated blockchain network is used to test the proposed model more effectively. Test results indicate that the proposed model, which is a new approach in the literature making use of machine learning for the construction of consensus committee, successfully selects the node with the higher reputation for the consensus group. (C) 2019 Elsevier B.V. All rights reserved.
Citation Count: Sever, Hayri; Senol, Ahmet; Elbasi, Ersin, "Block Size Analysis for Discrete Wavelet Watermarking and Embedding a Vector Image as a Watermark", International Arab Journal of Information Technology, Vol. 16, No. 6, pp. 1036-1043, (2019).
Block Size Analysis for Discrete Wavelet Watermarking and Embedding a Vector Image as a Watermark
(Zarka Private Univ, 2019) Sever, Hayri; Şenol, Ahmet; Elbaşı, Ersin; 11916
As telecommunication and computer technologies proliferate, most data are stored and transferred in digital format. Content owners, therefore, are searching for new technologies to protect copyrighted products in digital form. Image watermarking emerged as a technique for protecting image copyrights. Early studies on image watermarking used the pixel domain whereas modern watermarking methods convert a pixel based image to another domain and embed a watermark in the transform domain. This study aims to use, Block Discrete Wavelet Transform (BDWT) as the transform domain for embedding and extracting watermarks. This study consists of 2 parts. The first part investigates the effect of dividing an image into non overlapping blocks and transforming each image block to a DWT domain, independently. Then, effect of block size on watermark success and, how it is related to block size, are analyzed. The second part investigates embedding a vector image logo as a watermark. Vector images consist of geometric objects such as lines, circles and splines. Unlike pixel-based images, vector images do not lose quality due to scaling. Vector watermarks deteriorate very easily if the watermarked image is processed, such as compression or filtering. Special care must be taken when the embedded watermark is a vector image, such as adjusting the watermark strength or distributing the watermark data into the image. The relative importance of watermark data must be taken into account. To the best of our knowledge this study is the first to use a vector image as a watermark embedded in a host image.
Citation Count: Cetinkaya, F. C.; Catmakas, H. A.; Gorur, A. K., "Single-Machine Scheduling of Indivisible Multi-Operatıon Jobs", South African Journal of Industrial Engineering, Vol. 30, No. 1, pp. 78-93, (May 2019).
Single-Machine Scheduling of Indivisible Multi-Operatıon Jobs
(Southern African Inst Industrial Engineering, 2019) Çetinkaya, Ferda Can; Akkocaoğlu Çatmakaş, Hale; Görür, Abdül Kadir; 50129; 57532; 107251
This paper considers a single-machine scheduling problem of multi-operation jobs where each job consists of several operations processed contiguously, rather than being intermingled with the operations of different jobs. That is, the jobs are indivisible. A sequence-independent setup is required if the machine switches from one operation to another. However, no setup is necessary before the first operation of a job if this first operation is the same as the last operation of the immediately previous job. A job is complete when all of its operations have been processed. We investigate the problem for two cases. Makespan, which is the time needed to complete all jobs, is minimised in the first case; whereas the total completion time, which is the sum of the job completion times, is minimised in the second case. We show that the makespan problem is solvable in polynomial time. For the problem of minimising total completion time, we develop a mixed integer linear programming (MILP) model, which is capable of solving small and medium-sized problem instances optimally, and obtain a very small gap between the solution found and the best possible solution for the unsolved large-sized problem instances.

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