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Yazılım Mühendisliği Bölümü

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Browsing Yazılım Mühendisliği Bölümü by Author "Choupanı, Roya"

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    Article
    Hand Gesture Recognition in Variable Length Sequences
    (2005) Choupanı, Roya; Choupani, R.; Tolun, M.R.; Tolun, Mehmet Reşit; 1863; Bilgisayar Mühendisliği; Yazılım Mühendisliği; 06.01. Bilgisayar Mühendisliği; 06.09. Yazılım Mühendisliği; 06. Mühendislik Fakültesi; 01. Çankaya Üniversitesi
    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.
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    Conference Object
    Citation - WoS: 2
    Multiple Description Scalable Coding for Video Transmission Over Unreliable Networks
    (Springer-verlag Berlin, 2009) Choupanı, Roya; Choupani, Roya; Tolun, Mehmet Reşit; Wong, Stephan; Tolun, Mehmet R.; 1863; Bilgisayar Mühendisliği; Yazılım Mühendisliği; 06.01. Bilgisayar Mühendisliği; 06.09. Yazılım Mühendisliği; 06. Mühendislik Fakültesi; 01. Çankaya Üniversitesi
    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.
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    Conference Object
    Recent Challenges in Video Coding and Streaming
    (2006) Choupanı, Roya; Choupani, R.; Tolun, M.R.; Tolun, Mehmet Reşit; 1863; Bilgisayar Mühendisliği; Yazılım Mühendisliği; 06.01. Bilgisayar Mühendisliği; 06.09. Yazılım Mühendisliği; 06. Mühendislik Fakültesi; 01. Çankaya Üniversitesi
    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.
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    Conference Object
    Citation - Scopus: 3
    Scalable Video Transmission Over Unreliable Networks Using Multiple Description Wavelet Coding
    (2011) Choupanı, Roya; Choupany, R.; Wong, S.; Tolun, M.; 1863; Bilgisayar Mühendisliği; 06.01. Bilgisayar Mühendisliği; 06. Mühendislik Fakültesi; 01. Çankaya Üniversitesi
    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. © 2011 AICIT.