Elektronik ve Haberleşme Mühendisliği Bölümü Yayın Koleksiyonu
Permanent URI for this collectionhttps://hdl.handle.net/20.500.12416/260
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Conference Object Diffraction of Matter Waves in Time by an Absorbing Half-Screen(2010) Umul, Y.Z.; Umul, Yusuf Ziya; Elektronik ve Haberleşme MühendisliğiIn this study, the scattering of matter waves that accompany to the quantum particles by an absorbing half-plane is examined. A quantum shutter, which is opened at an initial time, is proposed to close the semi-infinite complementary aperture of the half-screen. Hence the matter waves, confined in a determined region of space, transmits to the second region by scattering from the semi-infinite aperture. The mathematical expressions of the scattered fields are plotted numerically and interpreted according to the diffraction theory of Young.Book Review Citation - WoS: 4Citation - Scopus: 5The Theory of the Boundary Diffraction Wave(Elsevier Academic Press inc, 2011) Umul, Yusuf ZiyaArticle Odak Dışı Beslemeli Silindirik Parabolik Reflektör Antenlere Ait Işıma İntegralinin Optimizasyonu(2005) Yalçın, Uğur; Umul, Yusuf ZiyaBu çalışmada, ( , ,z ρ 0 φ0 ) koordinatlarına yerleştirilmiş çizgisel akım kaynağıyla beslenen, z eksenine paralel sonsuz uzun mükemmel iletken içbükey silindirik parabolik reflektör antenden saçılma problemi göz önüne alınmıştır. İlk olarak, Hertz vektörüne ait yüzey ışıma integrali Fiziksel Optik (FO) yöntemi kullanılarak belirlenmiştir. Bu integral ifadesin de görülen Green fonksiyonu tanımlanmış ve yüzeye ait normal birim vektörü ile yüzeye gelen toplam magnetik alan bileşeninin vektörel çarpımı elde edilmiştir. Daha sonra bu ifadeler ışıma integralinde yerine yazılmış ve integralin ' z katı hesaplanmıştır. Neticede, FO ışıma integrali sadece ' φ katına bağlı olarak ifade edilebilmiştir. Elde edilen integral ifadesinden faydalanılarak anten sistemine ait ışıma diyagramları, ilgili parametrelerin çeşitli değerleri için polar koordinatlarda çizdirilmiş ve böyle bir anten sisteminin tasarımı için en optimum durum araştırılmıştır. Çalışmada silindirik parabolik reflektör antenin çalışma frekansı 2 (GHz) olarak seçilmiştirConference Object Comparison of physical optics integral and exact solutions for cylinder problem(2003) Umul, Yusuf Ziya; Yengel, Emre; Aydın, AyhanThe sound source composition of the urban sound environment varies depending on the geography and socio-cultural context. Current sound taxonomies in the literature categorize urban sound sources by their source types (e.g., human-made, natural, electromechanical) and respective semantic attributes. This study aims to add another taxonomical layer to the existing urban sound source categorization methods. The additional layer is a recently proposed sound source classification framework (CLIC). The CLIC framework identifies sound sources based on their Diegesis and Intention parametric attributes. The former parametric attribute, diegesis, was derived from film sound design. The geographical and socio-cultural context of the built environment can be considered as its narrative; hence, every event that happens within the functional context can be called diegetic, while the events that do not belong to that specific place can be called nondiegetic. The latter parametric attribute, intention, was derived from product design. One of the prominent sound source categorization methods in product sound design is to group the product emitted sounds as consequential and intentional. Combining these two parametric attributes with the existing taxonomies, the CLIC framework outputs a place-specific design guideline, clearly dictating the actions a sound designer should take. The two parametric attributes group the sound sources under four distinct areas, which dictates the degree of influence of designers on the specific sound source. The four zones are defined as the creation zone, limitation zone, isolation zone, and control zone. Each zone dictates step-by-step sound design instructions for the sound designer. This study consists of two main phases: field recordings and web-based listening tests. The sound sources present in the urban sound environment were identified in the field recordings phase. Later, in the web-based listening tests phase, the identified sound sources were evaluated based on the CLIC framework, and hence, their respective zones on the model were identified. The outcomes of the study propose clear step-by-step design guidelines and present action suggestions for environmental sound designers.Article Diffraction Theory of Waves by Resistive Surfaces(2010) Umul, Yusuf Ziya; Yalçın, UğurDiffraction of scalar plane waves by resistive surfaces are investigated by defining a new boundary condition in terms of the Dirichlet and Neumann conditions. The scattering problems of waves by a resistive half-plane and the interface between resistive and perfectly magnetic conducting half-planes are examined with the developed method. The resulting fields are plotted numerically. The numerical results show that the evaluated field expressions are in harmony with the theory.Conference Object İki izorefraktif ortam arasına yerleştirilmiş empedans sınır koşuluna sahip yarım düzlemden düzlemsel dalgaların saçılması(2016) Başdemir, Hüsnü Deniz; Umul, Yusuf Ziyaİki izorefraktif ortamın sınırına yerleştirilmiş empedans sınır koşuluna sahip bir yarım düzlemden düzlemsel dalgaların saçılması incelenir. Elde edilen alan ifadeleri sayısal olarak analiz edilir.Article Citation - WoS: 1Citation - Scopus: 2Wave Diffraction by a Thin Lossy Dielectric Half-Plane(Elsevier Gmbh, 2021) Umul, Yusuf ZiyaThe scattering of electromagnetic waves by a thin lossy dielectric half-plane is investigated. With this aim, the interaction process of waves with a dielectric layer is studied. The reflection and transmission coefficients are obtained in the limiting case, which is defined when the thickness of the layer is sufficiently smaller than the wavelength. The diffracted waves by the half-plane are evaluated using the method of transition boundary. Some numerical results are given. We will study the interaction problem of electromagnetic waves by a thin lossy dielectric half-plane in this paper. It will be supposed that the width of the dielectric layer is sufficiently smaller than the wavelength of the incident field. In the literature, such a structure is modeled by the resistive boundary conditions [1]. The scattering of waves by a resistive half-plane has been investigated in the literature by some authors [2-9]. Rawlins [10] solved the diffraction problem of plane waves by a thin dielectric half-screen by using approximate boundary conditions. Anderson [11] studied the same scenario and obtained a solution with the method of dual integral equation. A Wiener-Hopf approach was applied by Chakrabarti [12] to the dielectric half-plane, illuminated by a plane electromagnetic wave. Senior and Volakis [13] derived approximate boundary conditions for a thin dielectric layer and applied them to the diffraction problem, under consideration, for magnetic polarization [14]. We will take into consideration a lossy dielectric layer with finite width d and derive the reflected and transmitted electromagneticArticle Citation - WoS: 1Citation - Scopus: 1Wave Diffraction by a Perfect Magnetic Conductor Half-Plane Between Free Space and Anisotropic Plasma(Elsevier Gmbh, 2020) Umul, Yusuf ZiyaThe diffraction of magnetic polarized electromagnetic plane waves by a perfect magnetic conductor half-screen, located between free space and anisotropic plasma, is studied. The method of transition boundary is used for the solution of the problem. The scattered GO wave is obtained. The diffracted fields are derived with the aid of the scattered GO wave. The uniform expressions of the edge diffracted waves are derived. The behaviors of the evaluated fields are investigated numerically.Article The Standing Matter Waves and Bohm's Quantum Potential(Elsevier Gmbh, 2021) Umul, Yusuf ZiyaThe standing wave type wave functions are investigated in terms of Bohm's decomposition of the Schro spacing diaeresis dinger equation. It is shown that the quantum potential, obtained for the standing matter waves, is always different from zero. However, it is also put forth that the wave function do not satisfy the Bohm's equations except one case, which is defined in the Cartesian coordinates. The Airy type matter wave is also analyzed in terms of the Bohmian approach.Article Citation - WoS: 2Citation - Scopus: 8Scattering of Electromagnetic Waves by an Impedance Sheet Junction in Anisotropic Plasma(Elsevier Gmbh, 2020) Umul, Yusuf ZiyaThe diffraction of electromagnetic plane waves by the edge discontinuity of an impedance sheet junction, which is located in an anisotropic plasma, is investigated. The problem is solved by the integral theory of diffraction. The scattering integral is obtained from the scattered geometric optics wave. The diffracted fields are derived by the edge point evaluation of the scattering integral. The evaluated field expressions are analyzed numerically.