Bilgisayar Mühendisliği Bölümü Yayın Koleksiyonu
Permanent URI for this collectionhttps://hdl.handle.net/20.500.12416/253
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Conference Object Citation - WoS: 2Citation - Scopus: 4Component-Based Software Development With Component Variants(Acta Press Anaheim, 2007) Tolun, Mehmet Reşit; Altunel, Yusuf; Tolun, Mehmet R.; Yazılım MühendisliğiVariants 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.Conference Object Citation - Scopus: 1Adaptive Embedded Zero Tree for Scalable Video Coding(int Assoc Engineers-iaeng, 2011) Choupanı, Roya; Choupani, Roya; Tolun, Mehmet Reşit; Wong, Stephan; Tolun, Mehmet R.; Bilgisayar Mühendisliği; Yazılım MühendisliğiVideo 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.Conference Object Citation - Scopus: 4A 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.Article Citation - WoS: 2Citation - Scopus: 3A 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.