39 sonuçlar
Arama Sonuçları
Listeleniyor 1 - 10 / 39
Yayın EEG signal compression based on classified signature and envelope vector sets(Wiley, 2009-03) Gürkan, Hakan; Güz, Ümit; Yarman, Bekir Sıddık BinboğaIn this paper, a novel method to compress electroencephalogram (EEG) signal is proposed. The proposed method is based on the generation process of the classified signature and envelope vector sets (CSEVS), which employs an effective k-means clustering algorithm. It is assumed that both the transmitter and the receiver units have the same CSEVS. In this work, on a frame basis, EEG signals are modeled by multiplying only three factors called as classified signature vector, classified envelope vector, and gain coefficient (GC), respectively. In other words, every frame of an EEG signal is represented by two indices R and K of CSEVS and the GC. EEG signals are reconstructed frame by frame using these numbers in the receiver unit by employing the CSEVS. The proposed method is evaluated by using some evaluation metrics that are commonly used in this area such as root-mean-square error, percentage root-mean-square difference, and measuring with visual inspection. The performance of the proposed method is also compared with the other methods. It is observed that the proposed method achieves high compression ratios with low-level reconstruction error while preserving diagnostic information in the reconstructed EEG signal.Yayın Design of a broadband microwave amplifier constructed with mixed lumped and distributed elements for mobile communication(IEEE, 2002) Yarman, Bekir Sıddık Binboğa; Çimen, Ebru GürsuIn this paper, we designed a broadband microwave amplifier utilizing. the "semi-analytic method to describe symmetrical lossless two-ports with two-kinds of elements", namely, distributed and lumped elements in cascade connection. It is expected that the results presented in this paper will find immediate application to design analog/digital mobile communication systems put on MMICs or VLSI chips.Yayın Generation of optimum signature base sequences for speech signals(IEEE, 2000) Yarman, Bekir Sıddık Binboğa; Akdeniz, RafetIn our previous publications [1-6], we proposed a novel method to represent signals in terms of, so called, "Signature Base Functions-SBF' which were extracted from the physical features of the waveform under consideration. In [1-6], SBF were determined in ad-hoc manner, which requires tedious search process, and they were not orthogonal. Furthermore, optimality of SBF was in question. In this work however, we suggest a well-organised procedure to generate "Optimum Orthogonal Signature Base Functions-OSBF' for selected waveforms, which in turn provides excellent means for signal representations. II is shown that the new method of signal representation, which is based on OSBF, requires less computation time with substantial signal compression and results in efficient speaker dependent recognition.Yayın Cascade synthesis of two-variable lossless two-port networks with lumped elements and transmission lines: a semi-analytic procedure(Tylor & Francis Ltd, 2001) Aksen, Ahmet; Yarman, Bekir Sıddık BinboğaTwo-variable characterization of cascades composed of lossless two-port networks with lumped elements and transmission lines is considered. The problems associated with the construction of scattering functions in two variables are discussed and for cascade synthesis of two-variable mixed element networks, a semi-analytic procedure utilizing the topologic restrictions is proposed. Some particular mixed lumped-distributed structures for which the proposed procedure ends up with explicit formulas are addressed and the application of the results in real frequency broadband matching is indicated.Yayın A broadband microwave amplifier design by means of immittance based data modelling tool(IEEE, 2002) Kılınç, Ali; Pınarbaşı, Hacı; Şengül, Metin; Yarman, Bekir Sıddık BinboğaIn this paper a practical broadband microwave amplifier design algorithm is introduced utilizing the immittance data-modelling tool. In the course of design, first, the optimum input and output terminations for the active device are produced employing the real frequency technique. Then, these terminations are modelled utilizing the new immittance-modelling tool to synthesize the front-end and back-end matching networks. An example is included to exhibit the implementation of the proposed design algorithm to construct a single stage BJT amplifier over a wide frequency band. It is expected that the proposed design algorithm will find applications to realize wideband microwave amplifiers put on MMIC for mobile communication.Yayın A single matching network design for a dual band PIFA antenna via simplified real frequency technique(2006-10) Lindberg, Peter; Şengül, Metin; Çimen, Ebru Gürsu; Yarman, Bekir Sıddık Binboğa; Rydberg, Anders; Aksen, AhmetIn this paper, the matched performance of a dual band PIFA antenna is reported. The return loss of the antenna has been optimized over the popular commercial wireless communication bands of 824-960 MHz and 1710-1990 MHz using only one matching network. The network was synthesized using the Simplified Real Frequency Technique, which yields an "easy to implement circuit topology" and realizable component values. With the implemented matching network, a simultaneous measured bandwidth enhancement of 58% and 127% has been achieved in the low and high frequency band, respectively, without significant reduction of radiation efficiency.Yayın Immitance data modelling via linear interpolation techniques(IEEE, 2002) Yarman, Bekir Sıddık Binboğa; Aksen, Ahmet; Kılınç, AliWith the advancement of the manufacturing technologies to produce new generation analog/digital communication systems, immitance data modelling has gained renewed importance in the literature. Specifically, models are utilised for behaviour characterisation, simulation of physical devices or to design sub-systems with active and passive solid-state components. Therefore, in this paper, new computer aided tools are presented to model one port immitance data by means of linear interpolation techniques. It is remarkable to observe that complex electrical behaviour of physical devices can be simulated with the models built utilising the linear interpolation of a few properly selected measured immitance data. An antenna example is presented to exhibit the implementation of the proposed techniques. It is expected that the new modelling tools will be employed to provide initial circuit topologies to the commercially available analysis/simulation and design packages.Yayın Representation of speech signals by single signature base function within optimum frame length(IEEE, 2000) Akdeniz, Rafet; Yarman, Bekir Sıddık BinboğaBefore this study, we proposed a novel method to represent signals in terms of, so called, “Signature Base Functions-SBF" which were extracted from the physical features of the waveform under consideration. SBF were determined in ad-hoc manner, which requires tedious search process, and they were not orthogonal. Furthermore, optimality of SBF was in question. In this work however, we suggest a well-organized procedure to generate “Optimum Orthogonal Signature Base Functions-OSBF" for selected waveforms, which in turn provides excellent means for signal representations. It is shown that the new method of signal representation, which is based on OSBF, requires less computation time with substantial signal compression and results in efficient speaker dependent recognition.Yayın A numerical real frequency broadband matching technique based on parametric representation of scattering parameters(IEEE, 1998-11-24) Aksen, Ahmet; Çimen, Ebru Gürsu; Yarman, Bekir Sıddık BinboğaIn this study, a computer, aided broadband matching technique based on the parametric representation of scattering parameters is proposed. The new technique combines the advantageous of the so called parametric approach utilizing the impedance formalizm and the real frequency scattering technique. With the reformulation of these real frequency techniques, some laborous numerical computational steps are omitted. The descriptive network functions are obtained in an explicit form without any need to the polynomial factorizations and the solution of equation sets. The application of the technique and the comparision of the results with those of the other real frequency approaches is discussed on examples.Yayın Immitance data modelling via linear interpolation techniques: a classical circuit theory approach(Wiley-Blackwell, 2004-11) Yarman, Bekir Sıddık Binboğa; Kılınç, Ali; Aksen, AhmetWith the advancement of the manufacturing technologies to produce new generation analog/digital communication systems, immitance data modelling has gained renewed importance in the literature. Specifically, models are utilized for behaviour characterization, simulation of physical devices or to design sub-systems with active and passive solid-state devices. Therefore, in this paper, new computer aided tools are presented to model one port immitance data by means of linear interpolation techniques. The basic philosophy of the new modelling tools is based on the numerical decomposition of the immitance data into its minimum and Foster parts. Computer algorithms are presented to model the minimum and the Foster parts of the given immitance data. Implementations of these algorithms are exhibited by means of examples. Depending on the application, modelling tools based on linear interpolation techniques may present 'computational and practical' advantages over the existing interpolation techniques, non-linear curve fittings or regression methods. It is expected that the new modelling tools will be utilized to provide initial circuit topologies to the commercially available analysis/simulation and design packages.
