Scopus İndeksli Yayınlar Koleksiyonu
Permanent URI for this collectionhttps://hdl.handle.net/20.500.12416/8651
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Conference Object Citation - WoS: 5Citation - Scopus: 33A New Narrow Band Dual-Mode Microstrip Slotted Patch Bandpass Filter Design Based on Fractal Geometry(Ieee, 2012) Eyyuboğlu, Halil Tanyer; Mezaal, Yaqeen S.; Eyyuboglu, Halil Tanyer; Elektronik ve Haberleşme MühendisliğiA narrowband, compact, and easily fabricated microstrip bandpass filter design is introduced in this paper as a candidate for use in modern wireless systems. The proposed filter design is based on the use of dual-mode (two pole) square slotted microstrip resonator. This microstrip bandpass filter has the advantages of possessing much narrower and sharper performance responses than those of the single mode resonator and conventional square patch filter. The proposed microstrip filter structure is fractally generated using Sierpinski fractal curve geometry applied to the conventional square microstrip patch. Filter structures resulting from the successive iterations in the fractal generation process show a considerably low insertion loss, and sharper response of about 1% fractional bandwidth as compared with the conventional microstrip square patch filter of 3% fractional bandwidth designed at the same frequency using the same substrate material. The performance of filter structures, based on dual-mode resonators up to the third iterations, has been evaluated using a full-wave based electromagnetic simulator Sonnet software package. Performance simulation results show that these filter structures offer narrower fractional bandwidth percentages as compared with other types of non- fractalized filter structures.Conference Object Citation - WoS: 1Citation - Scopus: 1Off-Axis Field Correlations in Turbulence(Ieee, 2013) Baykal, Yahya Kemal; Baykal, Yahya; Elektrik-Elektronik MühendisliğiThe field correlations in atmospheric turbulence are evaluated for off-axis optical incidence. Within the practical range of the source and the medium parameters, increase in the diagonal length at the receiver plane is found to decrease the off-axis field correlations in turbulence. At a fixed diagonal length at the receiver plane, off-axis beams that have smaller displacement parameters and larger source sizes possess larger field correlations. When the field correlations of the off-axis beams in atmospheric turbulence are compared to their no turbulence counterparts, it is observed that the behaviour of the field correlation variations do not change, however the field correlations in turbulence diminish at smaller diagonal lengths.Conference Object Fluorescent On-Chip Imager by Using a Tunable Absorption Filter(Ieee, 2017) Arpali, Caglar; Yıldırım, Ender; Yildirim, Ender; Arpali, Çağlar; Arpali, Serap Altay; Arpali, Serap; Makine Mühendisliği; Mekatronik Mühendisliği; Elektronik ve Haberleşme MühendisliğiConference Object Citation - WoS: 12Citation - Scopus: 13A Reconfigurable Microfluidic Transmitarray Unit Cell(Ieee, 2013) Erdil, Emre; Yıldırım, Ender; Topalli, Kagan; Zorlu, Ozge; Toral, Taylan; Yildirim, Ender; Kulah, Haluk; Civi, Ozlem Aydin; Makine MühendisliğiThis paper presents a novel microfluidics based approach to develop a reconfigurable circularly polarized transmitarray unit cell. The unit cell comprises double layer nested split ring slots formed as microfluidic channels that can be filled by fluids. Split regions in the slots are realized by injecting liquid metal into the channels. Beam steering is obtained by implementing rotational phase shifting via manipulating the liquid metal in the slots. X-band unit cell prototypes are fabricated on glass substrate carrying a patterned metal film, and the slot channels are formed by Polydimethylsiloxane (PDMS) using soft lithography techniques.Conference Object Citation - WoS: 1Citation - Scopus: 2Wideband Hexagonal Type Antenna Design for 5g Networks(Ieee, 2017) Yildiran, Orcun; Başdemir, Hüsnü Deniz; Basdemir, Husnu Deniz; Yildiran, Urçun; Elektronik ve Haberleşme MühendisliğiIn this paper, hexagonal type antenna for the next generation (5G) mobile networks is proposed. Both the microstrip feed line and coaxial feed techniques are used to feed the antenna. The best feed point location for both techniques is found to achieve the highest performance. The High Frequency Structural Simulator (HFSS 12.0) is used to simulate the antenna and find out the characteristics. The antenna performance characteristics such as VSWR, return loss, radiation pattern are obtained.Conference Object Citation - Scopus: 1Use of Matrix Pade Approximation in the Analysis of Irregularly Shaped Patch Antennas With Multiport Network Model(Ieee, 2009) Sener, Goker; Alatan, Lale; Kuzuoglu, MustafaA new procedure for implementing the multiport network model for analyzing two-dimensional microwave circuits is proposed. The proposal procedure leads to more efficient evaluation of impedance matrices than the procedure known earlier. The computational efforts in the two procedures are compared.Conference Object Citation - WoS: 5Citation - Scopus: 3Temperature Dependence of the Brillouin Frequency Shift and the Linewidth of the La Mode in the Ferroelectric Phase of Pzt-X (pbzr1-Xtixo3)(Ieee, 2015) Yurtseven, F.; Korkmaz, C. Sisman; Kiraci, A.; Yurtseven, H.; Sisman Korkmaz, C.The temperature dependence of the Brillouin frequency and the linewidth of the LA mode is studied for the concentration of x=0.45 in the ferroelectric phase of PbZr1-xTixO3 (PZT-x) within the temperature range of 443 to 656 K (T-C=657 K). Using the experimental data for the Brillouin frequency of the LA mode as an order parameter below T-C the temperature dependence of the linewidth (FWHM) is calculated by the pseudospin-phonon coupled model and the energy fluctuation model for the lead titanate zirconate (x=0.45). Additionally, the activation energies are compared from the damping constant (linewidth) using both models for the temperature range of 443 to 656 K in the ferroelectric phase of PbZr1-xTixO3. Our calculated values for the damping constant are in agreement with the observed data for the ferroelectric phase of PbZr1-xTixO3 single crystals. The activation energies calculated from both models are much higher in the ferroelectric phase than the value of k(B)T(C)=0.056 eV at the transition temperature for PbZr1-xTixO3 (x=0.45).Conference Object Citation - WoS: 1Citation - Scopus: 1Tablet Pc in Restaurant(Ieee, 2013) Ali, Ali Adil; Mahdi, Hussain FalihThe growth of wireless technology and tablet PC in this era is creating a great impact on our lives. Some early efforts have been made to combine and utilize both of these technologies in advancement of hospitality industry. Nowadays, the majority of restaurants are still operating in an old fashioned way, by using pen and paper to register the orders of customers. The problem using "traditional menu" is probability of paper lost high and misinterprets the handwriting of order. "TPIR" is designed to overcome this problem. By using "tablet PC", the customer can send orders to the cooking room and cashier in a fast and easy way. TSIR can also give customer feedback to restaurant staff. The methodology that has been used in this project is based on wireless communication (Wi-Fi). This system is developed by using (visual basic 6.0 and SQL server 2000). This system makes the food ordering process easier. This system, implements wireless data access to SQL server. The Windows 7 application on customer tablet pc will have all the menu details. The restaurant manager can manage the menu modifications easily, via adding and removing items.Conference Object Citation - WoS: 3Citation - Scopus: 22Stereo Vision and Statistical Based Behaviour Prediction of Driver(Ieee, 2007) Eren, Haluk; Celik, Uemit; Poyraz, MustafaThe goal of this project is to develop a webeam-based system for monitoring the activities of automobile drivers. As in any system deployed for monitoring driver activities, the primary goal is to distinguish between safe and unsafe driving actions. There is no fixed list of actions that qualifies the unsafe driving behaviors. In general, an activity or an action that reduces a driver's alertness of their surroundings should be classified as unsafe driving behavior. Some examples of unsafe driving behavior include fatigue, talking on a cellular telephone, eating, and adjusting the controls of the dashboard stereo while driving. In this study, we also investigated the relationship between 2D and 3D face and pose recognition.Conference Object Spend Portal: Linked Data Discovery Using Sparql Endpoints(Ieee, 2017) Yumusak, Semih; Aras, Riza Emre; Uysal, Elif; Dogdu, Erdogan; Kodaz, Halife; Oztoprak, KasimWe present the project SpEnD, a complete SPARQL endpoint discovery and analysis portal. In a previous study, the SPARQL endpoint discovery and analysis steps of the SpEnD system were explained in detail. In the SpEnD portal, the SPARQL endpoints are extracted from the web by using web crawling techniques, monitored and analyzed by live querying the endpoints systematically. After many sustainability improvements in the SpEnD project, the SpEnD system is now online as a portal. SpEnD portal currently serves 1487 SPARQL endpoints, out of which 911 endpoints are uniquely found by SpEnD only when compared to the other existing SPARQL endpoint repositories. In this portal, the analytic results and the content information are shared for every SPARQL endpoint. The endpoints stored in the repository are monitored and updated continuously.