Elektrik Elektronik Mühendisliği Bölümü Yayın Koleksiyonu
Permanent URI for this collectionhttps://hdl.handle.net/20.500.12416/411
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Conference Object Using wavelet transform self-similarity for effective multiple description video coding(IEEE, 2016) Choupani, Roya; Wong, Stephan; Tolun, MehmetVideo streaming over unreliable networks requires preventive measures to avoid quality deterioration in the presence of packet losses. However, these measures result in redundancy in the transmitted data which is utilized to estimate the missing packets lost in the delivered portions. In this paper, we have used the self-similarity property if the discrete wavelet transform (DWT) to minimize the redundancy and improve the fidelity of the delivered video streams in presence of data loss. Our proposed method decomposes the video into multiple descriptions after applying the DWT. The descriptions are organized in such a way that when one of them is lost during transmission, it is estimated using the delivered portions by means of self-similarity between the DWT coefficients. In our experiments, we compare video reconstruction in the presence of data loss in one or two descriptions. Based on the experimental results, we have ascertained that our estimation method for missing coefficients by means of self-similarity is able to improve the video quality by 2.14dB and 7.26dB in case of one description and two descriptions, respectively. Moreover, our proposed method outperforms the state-of-the-art Forward Error Correction (FEC) method in case of higher bit-rates.Conference Object Işık hüzmesi profili ölçme sistemi(2011) Bük, Murat; Baki, T.; Çil, Celal Zaim; Cambaz, Göknur; Baykal, Yahya Kemal; Erseven, S.; Karabulut, S.; Ertuğ, A. MithatConference Object Genişbant Erişim Telekomünikasyon Sistemlerinin Kullanım KriterleriKüçükoğlu, Afşin; Baykal, YahyaHızla artan bilgisayar ağı ihtiyacını gidermek ve yüksek hızı son kullanıcı noktalarına ulaştırabilmek amacıyla geliştirilmiş olan genişbant erişim sistemlerinin (access systems) teknolojik son durumu incelendi. Herhangi bir erişim uygulamasında kullanılması gereken tercih nedenleri karşılaştırıldı. Bu karşılaştırmayı sistematik olarak yapan internet tabanlı bir yazılım geliştirildi. Yazılımda, sistem kullanıcısının ihtiyacı ve mevcut altyapı faktörleri doğrultusunda hangi erişim sisteminin kullanıcı tarafından tercih edilmesi gerektiği kararına optimum olarak varılabilmesi hedeflendi. Çalışmamız, xDSL (x Digital Subscriber Line) ile Fiber Optic erişimlerini kapsayan kablolu ve LMDS (Local Multipoint Distribution Services) ile FSO (Free Space Optics) erişimlerini kapsayan kablosuz sistemleri içermektedir. Yazılım tarafından istenilen sorular ihtiyaç doğrultusunda cevaplandırıldığında, tüm sistemler bir ana karşılaştırma tablosunda toplanmakta, sistem maliyetleri de göz önüne alınarak bir karşılaştırma yapılmakta, sonuçta ise teknik ve ekonomik olarak uygulanabilir çözümler ve optimum çözüm önerilmektedir.Conference Object Conference Object Hand Gesture Classification Using Inertial Based Sensors via a Neural Network(IEEE, 2017) Akan, Erhan; Tora, Hakan; Uslu, BaranIn this study, a mobile phone equipped with four types of sensors namely, accelerometer, gyroscope, magnetometer and orientation, is used for gesture classification. Without feature selection, the raw data from the sensor outputs are processed and fed into a Multi-Layer Perceptron classifier for recognition. The user independent, single user dependent and multiple user dependent cases are all examined. Accuracy values of 91.66% for single user dependent case, 87.48% for multiple user dependent case and 60% for the user independent case are obtained. In addition, performance of each sensor is assessed separately and the highest performance is achieved with the orientation sensor.Conference Object Conference Object Comparison of Single Channel Indices for U-Net Based Segmentation of Vegetation in Satellite Images(SPIE, 2020) Ülkü, İrem; Barmpoutis, P.; Stathaki, T.; Akagündüz, ErdemHyper-spectral satellite imagery, consisting of multiple visible or infrared bands, is extremely dense and weighty for deep operations. Regarding problems related to vegetation as, more specifically, tree segmentation, it is difficult to train deep architectures due to lack of large-scale satellite imagery. In this paper, we compare the success of different single channel indices, which are constructed from multiple bands, for the purpose of tree segmentation in a deep convolutional neural network (CNN) architecture. The utilized indices are either hand-crafted such as excess green index (ExG) and normalized difference vegetation index (NDVI) or reconstructed from the visible bands using feature space transformation methods such as principle component analysis (PCA). For comparison, these features are fed to an identical CNN architecture, which is a standard U-Net-based symmetric encoder-decoder design with hierarchical skip connections and the segmentation success for each single index is recorded. Experimental results show that single bands, which are constructed from the vegetation indices and space transformations, can achieve similar segmentation performances as compared to that of the original multi-channel casePublication Alternative Enhancement of Associativity Based Routing (Aeabr) for Mobile Networks(Springer, 2010) Preveze, Barbaros; Safak, AyselThis study proposes an alternative enhancement for the Enhanced Associativity Based Routing (EABR) method which is a derivation of ABR (Associativity Based Routing) by relative speed and relative distance estimation using the received power strength (RPS) of the nodes. In this study, it is shown that EABR outperforms some other well known protocols. The performance of EABR is improved in terms of number of route reconstructions (RRC) and connected status percentage (CSP). Message overhead and bandwidth utilization is also investigated.Publication IEEE(2013 Ieee 52Nd Annual Conference On Decision and Control (Cdc), 2013) Schmidt, Klaus WernerReconfigurable manufacturing systems (RMSs) are designed to quickly adapt to new products and production requirements. To this end, RMSs need to be able to perform fast changes between different configurations. This paper investigates the reconfiguration of RMSs in a supervisory control framework. Different from previous work, we formulate and solve a reconfiguration problem that allows to start a newly requested configuration before the previously active configuration has been completed. Our solution is optimal in the sense that there is no other solution that enables an earlier start of the new configuration. The practicability of the proposed solution is demonstrated by a small RMS example.