Bildiri Koleksiyonu
https://hdl.handle.net/11491/2260
Proceeding Collection
2024-03-29T12:57:31Z
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Radar darbelerinin kümelenmesi için iki-aşamalı bir ayrıştırma tekniği
https://hdl.handle.net/11491/2085
Radar darbelerinin kümelenmesi için iki-aşamalı bir ayrıştırma tekniği
Gençol, Kenan
Darbe ayrıştırma alınan radar darbelerinin hangi kaynağa (vericiye) ait olduğunu belirleyen bir işlemdir. Darbe ayrıştırma teknikleri genel olarak darbelerin geliş zamanlarına göre aralık algoritmaları ve geliş açısı, frekans, darbe genişliği, darbe genliği gibi parametrelere göre çoklu-parametreli algoritmalar olarak iki kısma ayrılmaktadır. Geleneksel çokluparametreli ayrıştırmada darbe genişliği ve darbe genliği çoklu yol olgusunun darbe şeklinde yol açtığı bozunumlardan dolayı güvenilir parametreler olmamaktadır. Bu çalışmada bu probleme yönelik iki-aşamalı bir ayrıştırma tekniği önerilmiştir. İlk aşamada radar darbeleri frekans ve geliş açısı parametrelerine göre ayrıştırılmıştır. İkinci aşamada ise Levenberg-Marquardt optimizasyon algoritmasıyla öncelikle anten tarama hızı tahmin edilmiştir. Daha sonra bu bilgi geri beslenerek ilk aşamadaki kümeleme hatası düşürülmeye çalışılmıştır. Benzetim sonuçları bu hedefe ulaşıldığını göstermektedir.; Pulse deinterleaving is the process of identifying which received pulses belong to which emitter sources. Pulse deinterleaving techniques generally consist of multi-parameter algorithms that utilize pulse parameters such as angle of arrival, frequency, pulse width and pulse amplitude and interval-only algorithms. In conventional multi-parameter deinterleaving pulse width and pulse amplitude parameters are generally assumed to be unreliable parameters due to distortions caused by the multipath phenomenon in the channel. In this study, a two-stage deinterleaving technique is proposed for such deinterleaving problem. In the first stage radar pulses are deinterleaved according to their frequency and angle of arrival parameters. In the second stage antenna scan rates are firstly estimated by the Levenberg-Marquardt optimization algorithm and then this information is fed back to the first stage to decrease clustering errors. Simulation results show that this goal is accomplished.
25th Signal Processing and Communications Applications Conference, SIU 2017, 15 May 2017 through 18 May 2017,
2017-01-01T00:00:00Z
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The analysis of tissue temperature rise caused by linear array transducers with Program Spheresum
https://hdl.handle.net/11491/2081
The analysis of tissue temperature rise caused by linear array transducers with Program Spheresum
Güngör, Murat Alparslan; Karagöz, İrfan
Diagnostic ultrasounds transmit sound waves into the body, and thus reveal important information about it. Because the transmitted sound waves cause tissue heating, diagnostic ultrasounds can produce adverse biologic effects in tissue, namely, thermal bioeffect. Both tissue characters and ultrasound parameters affect the amount of temperature rise on the tissue. Program Spheresum [1] gives the temperature rise on the tissue scanned by a diagnostic ultrasound. This study compares tissue temperature rise due to linear array transducers with different parameters by using Spheresum. The results show that the maximum temperature rise is generally near the source surface in the linear array transducer application with high frequency for different focal points. Especially in tissue with a high absorption coefficient and for the linear array transducer with high frequency, tissue temperature rise near the source surface should be considered as the image resolution. © 2016 IEEE.
2016 International Conference on Optoelectronics and Image Processing, ICOIP 2016, 10 June 2016 through 12 June 2016,
2016-01-01T00:00:00Z
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Thin wideband infrared metamaterial absorber with coplanar metallic patches of different sizes
https://hdl.handle.net/11491/2082
Thin wideband infrared metamaterial absorber with coplanar metallic patches of different sizes
Üstün, Kadir; Turhan Sayan, Gönül
Infrared absorber concept is a vibrant research topic because of the importance of real world applications such as infrared detectors, thermal coolers and energy harvesters. In this paper, we propose and numerically analyze thin metamaterial structures designed to operate in Long Wave Infrared Region, one of the regions that atmosphere shows transparent behavior. It is demonstrated that one of the proposed structures attains absorptance values higher than 80 percent in the wavelength region from 8.14 ?m to 11.59 ?m. The absorber is thin with a thickness of about 700nm, excluding any additional substrate layer that might be needed for mechanical support. The absorber design approach used in study can be further improved to achieve even flatter absorption spectrum over the LWIR band optimizing the design parameters. © 2016 IEEE.
10th International Congress on Advanced Electromagnetic Materials in Microwaves and Optics, METAMATERIALS 2016, 19 September 2016 through 22 September 2016,
2016-01-01T00:00:00Z
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Wide bandwidth absorption in the MWIR region using a thin and simple metamaterial absorber
https://hdl.handle.net/11491/2083
Wide bandwidth absorption in the MWIR region using a thin and simple metamaterial absorber
Üstün, Kadir; Turhan Sayan, Gönül
In this study, metamaterial absorber structures that operate in the mid-wave infrared (MWIR) region are presented. The advantage of the design stems from the high absorptance in the region of interest and the ease of fabrication. Fabrication stage is facilitated by large in-plane geometric dimensions of the metamaterial pattern and small thickness of the full absorber geometry. © 2017 IEEE.
4th International Electromagnetic Compatibility Conference, EMC Turkiye 2017, 24 September 2017 through 27 September 2017,
2017-01-01T00:00:00Z