Electrical - Electronic Engineering / Elektrik - Elektronik Mühendisliği
Permanent URI for this collectionhttps://hdl.handle.net/11147/11
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Article Citation - WoS: 4Ramcess 2.x Framework-Expressive Voice Analysis for Realtime and Accurate Synthesis of Singing(Springer Verlag, 2008) d'Alessandro, Nicolas; Babacan, Onur; Bozkurt, Barış; Dubuisson, Thomas; Holzapfel, Andre; Kessous, Loic; Vlieghe, MaximeIn this paper we present the work that has been achieved in the context of the second version of the RAMCESS singing synthesis framework. The main improvement of this study is the integration of new algorithms for expressive voice analysis, especially the separation of the glottal source and the vocal tract. Realtime synthesis modules have also been refined. These elements have been integrated in an existing digital instrument: the HANDSKETCH 1.X, a bimanual controller. Moreover this digital instrument is compared to existing systems.Article Citation - WoS: 7Citation - Scopus: 8Performance Evaluation of Multicast Miso-Ofdm Systems(Springer Verlag, 2008) Özbek, Berna; Le Ruyet, Didier; Khanfir, HajerIn this paper, we analyze the performance of multicast orthogonal frequency division multiplexing (OFDM) systems with single and multiple transmit antennas. We show that the resource allocation that includes the subcarrier allocation, bit loading, and the precoding vector selection in the multiple-input single-output (MISO) case is a difficult optimization problem. Consequently, we propose suboptimal algorithms based on the maximization of the sum data rate and the maximization of the minimum user data rate criteria. For practical application, we consider a complete transmission chain by combining powerful erasure codes with the proposed algorithms. Using this scheme, we guarantee that each user receives the same amount of information to decode the same data. Simulation results show that, for both single-input single-output (SISO)-OFDM and MISO-OFDM cases, the proposed multicast OFDM systems achieve gains over the worst user case algorithm.Article A Novel All-Optical Routing Architecture for Optical Packet Switched Networks(Springer Verlag, 2006) Mocan, Bora; Dinleyici, Mehmet SalihIncreasing bandwidth demand, mostly driven by the Internet Protocol (IP), has made researchers consider to deploy all-optical devices into packet switched networks. Despite huge bandwidth of the optical communication links (optical fiber) the usable capacity is limited due to bottlenecks (congestions) at the switching nodes. In this paper, a novel all-optical routing architecture is proposed for optical packet switched networks. In the design, practical optical devices (gratings, threshold elements, optical delays, and couplers) have been improved and exploited in order to integrate into an all-optical routing device. The system has been implemented and simulated by using an photonics simulation package (VPI-Virtual Photonics). The packets conveying a three-bit routing information tag at the bit rate of 10 Gbps have been successfully routed between two links. Some of the components are standard tools of the simulation package and some needed to be designed using the transfer function or theory developed in the literature. Noise and losses associated to the nonideal nature of the components are considered in the simulation as well.Conference Object Citation - WoS: 1Citation - Scopus: 2A Case Study on Logging Visual Activities: Chess Game(Springer Verlag, 2006) Ozan, Şükrü; Gümüştekin, ŞevketAutomatically recognizing and analyzing visual activities in complex environments is a challenging and open-ended problem. In this study this task is performed in a chess game scenario where the rules, actions and the environment are well defined. The purpose here is to detect and observe a FIDE (Fédération International des Ėchecs) compatible chess board, generating a log file of the moves made by human players. A series of basic image processing operations have been applied to perform the desired task. The first step of automatically detecting a chess board is followed by locating the positions of the pieces. After the initial setup is established every move made by a player is automatically detected and verified. Intel® Open Source Computer Vision Library (OpenCV) is used in the current software implementation.Conference Object Citation - WoS: 3Citation - Scopus: 6Phase-Based Methods for Voice Source Analysis(Springer Verlag, 2007) D’Alessandro, Christophe; Bozkurt, Barış; Doval, Boris; Dutoit, Thierry; Henrich, Nathalie; Tuan, Vu Ngoc; Sturmel, NicolasVoice source analysis is an important but difficult issue for speech processing. In this talk, three aspects of voice source analysis recently developed at LIMSI (Orsay, France) and FPMs (Mons, Belgium) are discussed. In a first part, time domain and spectral domain modelling of glottal flow signals are presented. It is shown that the glottal flow can be modelled as an anticausal filter (maximum phase) before the glottal closing, and as a causal filter (minimum phase) after the glottal closing. In a second part, taking advantage of this phase structure, causal and anticausal components of the speech signal are separated according to the location in the Z-plane of the zeros of the Z-Transform (ZZT) of the windowed signal. This method is useful for voice source parameters analysis and source-tract deconvolution. Results of a comparative evaluation of the ZZT and linear prediction for source/tract separation are reported. In a third part, glottal closing instant detection using the phase of the wavelet transform is discussed. A method based on the lines of maximum phase in the time-scale plane is proposed. This method is compared to EGG for robust glottal closing instant analysis.Article Citation - WoS: 3Citation - Scopus: 2Analysis of Excitations for a Groove Guide Resonator at 10 Ghz by Means of the Fdtd Method(Springer Verlag, 2005) Bechteler, Thomas F.Various excitations of a new groove guide resonator working in the X-band (8 GHz - 12 GHz) are investigated by means of numerical simulations. For the numerical simulations the Finite-Difference Time-Domain method is used. The groove guide resonator, modelled both with and without excitation structures, is discretised in space. The results in the time domain are then transformed into the frequency domain in order to obtain the resonance frequency spectrum. Comparison between simulations with and without excitations shows the effect of the excitations on the resonance frequency spectrum. The results are compared with those of previous analytical methods.Article Citation - WoS: 5Citation - Scopus: 7An Experimental Work on Optical Component Based on D-fiber/Slab Evanescent Coupling Structure(Springer Verlag, 2003) Dinleyici, Mehmet SalihFiber/slab coupler structure has been exploited as a passive in-line optical fiber component for functions of filtering, intensity modulating and switching by many researchers. In this work a device based on the elliptic core D-fiber and polymer slab waveguide is proposed and its fabrication is experimentally investigated. The device is constructed by placing the polymer slab on the top of the flat side of the D-fiber, and then they are tested for transmission characteristics and polarization preserving properties for various configurations. The geometrical uniformity of the device is examined under Scanning Electron Microscope for the purpose of device performance evaluation. Potential usage of this device as an all-optical switch is also discussed at the end.Article Citation - WoS: 14Citation - Scopus: 14The Circuit Implementation of a Wavelet Function Approximator(Springer Verlag, 2002) Özkurt, Nalan; Savacı, Ferit Acar; Gündüzalp, MustafaThis paper describes the analog synthesis of a wavelet function approximator using sigmoidal mother wavelet. Any finite energy multivariate function can be approximated by this analog circuit using the multiresolution approximation property of the wavelet decomposition. The approximator circuit includes bipolar junction transistors, operational amplifiers and linear passive circuit elements.