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Öğe Radar darbelerinin kümelenmesi için iki-aşamalı bir ayrıştırma tekniği(Institute of Electrical and Electronics Engineers Inc., 2017) Gençol, KenanDarbe 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.Öğe Thin wideband infrared metamaterial absorber with coplanar metallic patches of different sizes(Institute of Electrical and Electronics Engineers Inc., 2016) Üstün, Kadir; Turhan Sayan, GönülInfrared 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.Öğe The analysis of tissue temperature rise caused by linear array transducers with Program Spheresum(Institute of Electrical and Electronics Engineers Inc., 2016) Güngör, Murat Alparslan; Karagöz, İrfanDiagnostic 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.Öğe Wide bandwidth absorption in the MWIR region using a thin and simple metamaterial absorber(Institute of Electrical and Electronics Engineers Inc., 2017) Üstün, Kadir; Turhan Sayan, GönülIn 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.Öğe Monitoring and control of PLC based motion control systems via device-net(Institute of Electrical and Electronics Engineers Inc., 2014) Işık, Mehmet Fatih; Haboğlu, Mustafa Reşit; Yanmaz, HilmiThe control of mechanical systems are generally applied by using electric motors which are useful for the control of velocity, position and torque. On the other hand, servo motors are preferred due to their characteristic properties for the systems that require more accurate operations. In this study, a mechanical prototype having a two degree of freedom motion capacity integrated with AC servo motors is generated. The control of those AC servo motors is achieved by using an Omron PLC (Programmable Logic Controller). A SCADA program is developed for user control and monitoring. The connection between SCADA and PLC is obtained by using Device-Net web protocol. The velocity and position of the motion control system are monitored with real time animation on the screen. It is observed after the testing of the designed system that the position and velocity values are convenient. © 2014 IEEE.Öğe The effects of the median filter with different window sizes for ultrasound image(Institute of Electrical and Electronics Engineers Inc., 2017) Güngör, Murat Alparslan; Karagöz, İrfanUltrasound is widely used in medical imaging. Unfortunately, speckle noise decreases the quality of the ultrasound image. One of the filters to reduce speckle noise in ultrasound image is the median filter. The median filter has no complex algorithms and there is no need for long time implementation of the median filter. Especially, for the portable ultrasound machines, the median filter is an important filter to reduce speckle noise. In this paper, we analyzed the effect of the median filter for ultrasonic imaging. To carry out our study we selected a kidney image simulated by the Field II program and a cameraman image from MATLAB. For the portable ultrasound machines, the performance of the median filter with the different window sizes is evaluated with the image quality metric and qualitative comparison. © 2016 IEEE.Öğe Broadband one way propagation via dielectric waveguides with unequal effective index(Institute of Electrical and Electronics Engineers Inc., 2014) Öner, Bilgehan Barış; Üstün, Kadir; Kurt, Hamza; Okyay, Ali Kemal; Turhan Sayan, GönülWe present an efficient approach for broad band one way propagation of light by parallel and unequal dielectric waveguides leading different effective phase shifts. Three dimensional numerical simulations show that 30% operating bandwidth is achieved. © 2014 IEEE.Öğe Design and development of an adaptable, lan-based training module for object lessons(2009) Işık, Mehmet Fatih; Yılmaz, CemalA training module, which is intended for object lessons of especially technical students has been developed through this work. The training module runs in the physical LAN environment that consists of a server and workstations that are connected to it. That module has been designed to be used for various different courses. Infrastructure of the developed software is flexible, versatile and updatable. Hardware infrastructure has been built and tested for sample course applications. Experiments and observations have revealed the fact that faculty members, as well as students, seem to be more eager and productive when working with visual applications. © 2009.Öğe Design and application of the technical training set for plc- based power supply unit developed for industrial applications(2009) Coşkun, İsmail; Işık, Mehmet FatihDesign and control of a prototype training set, which especially the students studying in institutions offering education at undergraduate and associate levels can employ as a PLC (Programmable Logic Controller)-controlled simulator of the power supply unit of electroerosion machinery (electrical discharge machinery) that are used frequently during industrial manufacturing processes, has been actualized through this work, for the purpose of training qualified technical personnel needed by companies, who are specialized in control and electromechanics. The training set, therefore, contributes to a large extent to the training process in favor of faculty members, who are to train personnel for the sector, and in favor of students, who should be able to acquire proper education. Working on the prototype allows students to acquire knowledge and practical skills and then make use of those skills for maintaintenance, repair and control of machinery. © 2009.Öğe Computer controlled test system for measuring the parameters of the real thermoelectric module(Elsevier Ltd, 2011) Ahıska, Raşit; Dişlitaş, SerkanDifferent methods have been developed for measuring the performances of thermoelectric (TE) modules. However, the foundation of these methods accepts the parameters of semiconductors as constant and foresees temperature changes. That is why, the performance calculations of TE modules and their evaluations turn out to be erroneous. The aim of this study was to analyze of the values of the output parameters of operating real TE modules and systems and to be able to make performance analyses. Accordingly, a new computer controlled test system based on the new method founded on easily measurable parameters such as temperature, current and voltage and composed of software and hardware was considered. In this study; algorithms for the determination of the experimental parameters Imax, Vmax and Emax and the output parameters QC, TC, COP, P, Z, K, and R of the TE module were developed and also system hardware and software were realized. The system's control and interface software was developed by Delphi visual programming language. In order to determine the performance of the developed system, Melcor CP1.0-127-05 model standard TE module was used experimental studies and the superiority of the new method were determined. © 2010 Elsevier Ltd. All rights reserved.
