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Yayın On a class of functional equations of the Wiener-Hopf type and their applications in n-part scattering problems(Oxford Univ Press, 2003-12) İdemen, Mehmet Mithat; Alkumru, AliAn asymptotic theory for the functional equation K-phi=f, where K : X-->Y stands for a matrix-valued linear operator of the form K=K1P1+K2P2+...+KnPn, is developed. Here X and Y refer to certain Hilbert spaces, {P-alpha} denotes a partition of the unit operator in X while K-alpha are certain operators from X to Y. One assumes that the partition {P-alpha} as well as the operators K-alpha depend on a complex parameter nu such that all K-alpha are multi-valued around certain branch points at nu=k(+) and nu=k(-) while the inverse operators K-alpha(-1) exist and are bounded in the appropriately cut nu-plane except for certain poles. Then, for a class of {P-alpha} having certain analytical properties, an asymptotic solution valid for \k(+/-)\-->infinity is given. The basic idea is the decomposition of phi into a sum of projections on n mutually orthogonal subspaces of X. The results can be extended in a straightforward manner to the cases of no or more branch points. If there is no branch point or n=2, then the results are all exact. The theory may have effective applications in solving some direct and inverse multi-part boundary-value problems connected with high-frequency waves. An illustrative example shows the applicability as well as the effectiveness of the method.Yayın A novel fast algorithm for speech and audio coding(IEEE, 2007) Güz, Ümit; Gürkan, Hakan; Yarman, Bekir Sıddık BinboğaIn this work a new mathematical modeling approach is proposed for the representation of the speech and audio signals. This approach is based on the generation of the so called Predefined Signature Sequence (PSS) and Predefined Envelope Sequence (PES) Sets. After the generation process of the PSS and PES sets, they are clustered by effective k-means clustering algorithm and the PSS and PES are redefined by using these centroids. By using this approach, the drawbacks by means of the size of the sets, speed of the reconstruction process (computational complexity) which arise in the proposed methods previously are highly eliminated. In spite of these improvements, the initial results proved that, the quality of the reconstructed signals remains within the limitations of the acceptable hearing quality.Yayın A novel method to represent the speech signals by using language and speaker independent predefined functions sets(IEEE, 2004) Güz, Ümit; Gürkan, Hakan; Yarman, Bekir Sıddık BinboğaIn this paper a new modeling method of speech signals is introduced. The proposed method is based on the generation of the so-called Predefined Signature S={s(R)(t)} and Envelope Function E = {e(K)(t)} Sets (PSEFS). These function sets are independent of any speaker and any language. Once the speech signals are divided into frames with selected lengths, then each frame signal piece X-i(t) is synthesized by means of the mathematical form of x(i)(t)=C(i)e(K)(t)s(R)(t). In this representation, C-i is called the frame coefficient, s(R)(t) and e(K)(t) are properly assigned from the PSEFS respectively. It is shown that the proposed method provides fast reconstruction and substantial compression with acceptable hearing quality.Yayın Real frequency design of multiband matching networks with mixed lumped-distributed elements and foster resonance sections(IEEE, 2018) Yıldız, Serkan; Aksen, Ahmet; Yarman, Bekir Sıddık BinboğaIn this study, a multiband matching network design technique is presented. Mixed lumped and distributed elements are used to form Transducer Power Gain (TPG) of the matching network. Finite frequency transmission zeros are included in final design to create multiband TPG characteristic. Foster resonance sections are used to realize finite transmission zeros. Approximate distributed model of Foster resonance section is incorporated in design. An illustrative dual band matching network design for a PIFA antenna is presented. It has been shown that using distributed equivalent models of Foster resonance sections in mixed matching network design provides satisfactory TPG levels at intended frequency bands.Yayın Gerçel ve karmaşık süzgeç öbeklerinin eşdalgacıklı tasarımı(IEEE, 2006-07-31) Ateş, Hasan Fehmi; Orchard, Michael T.; Kanberoğlu, BerkayBu bildiride, eşdalgacıklı tam geri çatma süzgeç öbekleri tasarlamak için, Parks-McClellan algoritması gibi tekniklerle üretilen enküçük-enbüyük optimal eşdalgacıklı kısıtsız süzgeçleri eşlemlemede kullanılan basit bir yöntem sunulmaktadır. Bu yöntem, hem standart alçak- ve yüksek geçiren süzgeçlerin tam geri çatması sağlayacak şekilde tasarımlarına hem de kritik örneklenmiş karmaşık süzgeçlerin tasarımlarına uygulanmıştır. Gerçel süzgeç öbeği tasarımı için, yöntemimiz, tam geri çatma kısıtlarını karşılayan ve aynı zamanda standart enküçük-enbüyük süzgeç tasarımı ölçütlerini eniyileyen eşdalgacıklı alçak ve yüksek geçiren süzgeçleri üretmektedir. Karmaşık süzgeç öbeği tasarımı için, yöntemimiz, tam geri çatmaya izin verirken aynı zamanda rezone eden sinyaller için kritik örneklenmiş bir zarf/faz gösterimi oluşturmaktadır. Karmaşık süzgecin genlik tepkisi, ideal pozitif bir frekans geçirme kuşağının eşdalgacıklı yaklaşımıdır. Faz tepkisi ise salt doğrusal fazın eşdalgacıklı yaklaşımıdır.
