Browsing by Author "Tolun, Mehmet R."

Now showing 1 - 13 of 13

Citation - WoS: 0
Citation - Scopus: 4
A drift-reduced scheme for hierarchical wavelet coding scalable video transmissions
(Ieee, 2009) Choupani, Roya; Wong, Stephan; Tolun, Mehmet R.
Scalable video coding allows for the capability of (partially) decoding a video bitstream when faced with communication deficiencies such as low handwidth or loss of data resulting in lower video quality. As the encoding is usually based on perfectly reconstructed frames, such deficiencies result in differently decoded frames at the decoder than the ones used in the encoder and, therefore, leading to errors being accumulated in the decoder. This is commonly referred to as the drift error. Drift-free scalable video coding methods also suffer from the low performance problem as they do not combine the residue encoding scheme of the current standards such as MPEG-4 and H.264 with scalability characteristics. We propose a scalable video coding method which is based on the motion compensation and residue encoding methods found in current video standards combined with the scalability property of discrete wavelet transform. Our proposed method aims to reduce the drift error while preserving the compression efficiency. Our results show that the drift error has been greatly reduced when a hierarchical structure for frame encoding is introduced.
Citation - WoS: 0
Citation - Scopus: 1
Adaptive Embedded Zero Tree For Scalable Video Coding
(int Assoc Engineers-iaeng, 2011) Choupani, Roya; Wong, Stephan; Tolun, Mehmet R.; 1863
Video streaming over the Internet has gained popularity during recent years mainly due to the revival of video-conferencing and video-telephony applications and the proliferation of (video) content providers. However, the heterogeneous, dynamic, and best-effort nature of the Internet cannot always guarantee a certain bandwidth for an application utilizing the Internet. Scalability has been introduced to deal with such issues (up to a certain point) by adapting the video quality with the available bandwidth. In addition, wavelet based scalability combined with representation methods such as embedded zero trees (EZWs) provides the possibility of reconstructing the video even when only the initial part of the streams have been received. EZW prioritizes the wavelet coefficients based on their energy content. Our experiments however, indicate that giving more priority to low frequency content improves the video quality at a specific bit rate. In this paper, we propose a method to improve on the compression rate of the EZW by prioritizing the coefficients by combining each frequency sub-band with its energy content. Initial experimental show that the first two layers of the generated EZW are about 22.6% more concise.
Bilgi Biliminin Mühendislik Gereksinimi ve Bilgi Mühendisliği
(2009) Medeni, İhsan Tolga; Aktaş, A. Ziya; Tolun, Mehmet R.; 1863; Bilgisayar Mühendisliği
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 - WoS: 1
Citation - Scopus: 2
Clustering Analysis for Vasculitic Diseases
(Springer-verlag Berlin, 2010) Yildirim, Pinar; Ceken, Cinar; Ceken, Kagan; 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.
Clustering Analysis for Vasculitic Diseases
(Springer-Verlag Berlin, 2010) Yıldırım, Pınar; Çeken, Çınar; Çeken, Kağan; Tolun, Mehmet R.; 1863
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.
Citation - WoS: 0
Citation - Scopus: 1
Component-Based Project Estimation Issues for Recursive Development
(Springer, 2008) Altunel, Yusuf; Tolun, Mehmet R.; 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 - WoS: 2
Citation - Scopus: 4
Component-based software development with component variants
(Acta Press Anaheim, 2007) Altunel, Yusuf; Tolun, Mehmet R.
Variants are the new units suggested for component-based software implementation to contain just one set of features that a traditional component might normally contain. They help us to implement the specialization of components without the need for long inheritance trees and strong dependencies in object oriented counterpart. Variants can become very effective in component customization process when the variant production is automated by means of variant generators. In this paper we provide a simple component-based methodology based on the variants that help us to implement software in pure component-based manner. Such an approach guarantees the execution of a uniform processes throughout the whole software development operation. A system produced by our methodology has the capacity to produce many generic and domain specific components as by-products that can be utilized in further applications. Our methodology includes the activities to identify, represent, decompose and optimize the components, sub-components and their variants.
Citation - WoS: 0
Citation - Scopus: 1
Induction for Radiology Patients
(Springer, 2009) Yildirim, Pinar; Tolun, Mehmet R.
This paper represents the implementation of an inductive learning algorithm for patients of Radiology Department in Hacettepe University hospitals to discover the relationship between patient demo-graphics information and time that patients spend during a specific radiology exam. ILA has been used for the implementation which generates rules and the results are evaluated by evaluation metrics. According to generated rules, some patients in different age groups or birthplaces may spend more time for the same radiology exam than the others.
Induction for radiology patients
(Springer, 2009) Yıldırım, Pınar; Tolun, Mehmet R.; 101956
This paper represents the implementation of an inductive learning algorithm for patients of Radiology Department in Hacettepe University hospitals to discover the relationship between patient demo-graphics information and time that patients spend during a specific radiology exam. ILA has been used for the implementation which generates rules and the results are evaluated by evaluation metrics. According to generated rules, some patients in different age groups or birthplaces may spend more time for the same radiology exam than the others.
Citation - WoS: 2
Multiple Description Scalable Coding for Video Transmission over Unreliable Networks
(Springer-verlag Berlin, 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 tip to 36dB for average Y-PSNR.
Citation - WoS: 2
Citation - Scopus: 3
A New Relational Learning System Using Novel Rule Selection Strategies
(Elsevier, 2006) Uludag, Mahmut; Tolun, Mehmet R.
This paper describes a new rule induction system, rila, which can extract frequent patterns from multiple connected relations. The system supports two different rule selection strategies, namely the select early and select late strategies. Pruning heuristics are used to control the number of hypotheses generated during the learning process. Experimental results are provided on the mutagenesis and the segmentation data sets. The present rule induction algorithm is also compared to the similar relational learning algorithms. Results show that the algorithm is comparable to similar algorithms. (c) 2006 Elsevier B.V. All rights reserved.
Production and retrieval off rough classes in multi relations
(IEEE Computer Soc, 2007) Sever, Hayri; Görür, Abdül Kadir; Görür, Abdül Kadir; 11916; 107251; Bilgisayar Mühendisliği
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.
Yazılım süreç iyileştirmede CASE aracı kullanımının CMMI süreç yönetimi kategorisi açısından değerlendirilmesi
(Çankaya Üniversitesi, 2010) Fidanboy, Cemalettin Öcal; Tolun, Mehmet R.; 1863
Yazılım mühendisliğinin bilgi alanlarından biri olan yazılım kalitesinin belirlenmesi için temel oluşturan model ve standartlar her geçen gün değer kazanmaktadır. Yazılım kalitesini belirleyen temel unsurlar; yazılım süreçlerinin kuruluş ihtiyaçlarına uygun olarak belirlenmesi, yönetilmesi ve sistematik olarak iyileştirilmesidir. Uluslararası yazılım süreç iyileştirme model ve standartları temel alındığında, yazılım geliştirme projelerinin yüksek kalite düzeylerine ulaşması, projelerin istenen sürede ve en uygun maliyette tamamlanması mümkün olmaktadır. Bütünleşik Yetenek Olgunluk Modeli (CMMI), yazılım geliştirme, bakım ve süreç iyileştirme konularında, en iyi yönetim uygulamalarının birleştirilmesi sonucu oluşturulan önemli modellerden birisidir. Yazılım süreç iyileştirme, çalışmalarında CASE (bilgisayar destekli yazılım mühendisliği) araçlarının kullanılması; süreç iyileştirme sisteminin verimli bir şekilde kurgulanması, etkin bir konfigürasyon yönetiminin sağlanması ve sağlam bir metrik altyapısının kurulması açısından önemli faydalar sağlamaktadır. Bu makalede, öncelikli olarak CMMI Süreç Yönetimi kategorisinde yer alan ve kurumsal süreç iyileştirme uygulamalarını hedefleyen Kurumsal Süreç Tanımı ile Kurumsal Süreç Odaklanması Süreç alanları tanıtılmaktadır. Aynı zamanda, CMMI Süreç Yönetimi kategorisi kapsamında CASE aracı kullanımına yönelik örnekler verilmektedir. Ek olarak, CASE aracı kullanımının yazılım süreç iyileştirme uygulamalarına etkisini ortaya çıkarmak üzere yapılan bir kullanıcı anketine ilişkin sonuçlar sunulmakta ve bahsi geçen konularda CMMI modeli açısından değerlendirme yapılmaktadır.