121 research outputs found
Frequency and impedance reconfigurable antennas for terahertz photomixers
No full textInstitute of Electrical and Electronics Engineers Inc.We present, for the first time, the design of two antennas for the terahertz photomixers that have reconfigurable operation frequency or reconfigurable input impedance as an alternative to the state-of-the-art high-impedance, narrow band or low-impedance, wide-band antennas. Both antennas have folded-dipole structures, which inherently have high radiation resistances, and the dimensions of the antennas are modified in the horizontal and vertical dimensions by means of ideal switches, changing the operation frequency of the antenna or the input impedance of the antenna at a given operation frequency. We also propose a real-life solution for the ideal switches for the antennas, namely miniature Micro-Electro-Mechanical Systems (MEMS) switches, which have an area of 10 um × 10 um and is, to the best of our knowledge, the smallest MEMS switch reported in the literature. The first antenna is capable of operating at three different frequencies of 200, 400, and 600 GHz, whereas the input impedance of the second antenna can be adjusted between 4 kΩ and 7.5 kΩ at an operation frequency of 385 GHz. The proposed antennas can also be used as a photoconductive antenna for the terahertz frequency band. © 2014 IEEE
Frequency and impedance reconfigurable antennas for terahertz photomixer
No full textWe present, for the first time, the design of two antennas for the terahertz photomixers that have reconfigurable operation frequency or reconfigurable input impedance as an alternative to the state-of-the-art high-impedance, narrow band or low-impedance, wide-band antennas. Both antennas have folded-dipole structures, which inherently have high radiation resistances, and the dimensions of the antennas are modified in the horizontal and vertical dimensions by means of ideal switches, changing the operation frequency of the antenna or the input impedance of the antenna at a given operation frequency. We also propose a real-life solution for the ideal switches for the antennas, namely miniature Micro-Electro-Mechanical Systems (MEMS) switches, which have an area of 10 um x 10 um and is, to the best of our knowledge, the smallest MEMS switch reported in the literature. The first antenna is capable of operating at three different frequencies of 200, 400, and 600 GHz, whereas the input impedance of the second antenna can be adjusted between 4 kΩ and 7.5 kΩ at an operation frequency of 385 GHz. The proposed antennas can also be used as a photoconductive antenna for the terahertz frequency band
Assessment of vestibulo-ocular reflex, central compensation, and the relationship between vestibular neurotomy and total labyrinthectomy patients with objective and subjective tests
No full textAmaç: Vestibüler sinir kesisi ve total labirentektomi cerrahi girişimlerinin vestibülo-okuler refleks (VOR) ve santral kompanzasyon üzerindeki etkilerin, objektif ve sübjektif testler ile ortaya konulması amaçlanmıştır. İkincil çıktı olarak vestibüler deafferasyon vakalarında, Video Head Impulse Test (VHIT) verilerinden VOR kazancına ek olarak kullanılabilecek parametrelerin var olup olmadığının tespit edilmesi hedeflenmiştir. Ayrıca klinik tecrübemizin literatür ile paylaşması düşünülmüştür. Materyal-Metod: Çalışmaya kliniğimizde daha önce operasyonları gerçekleştirilen 19 vestibüler nörektomi ile 18 total labirentektomi operasyonu geçirmiş ve operasyonu üzerinden en az bir yıl geçmiş olan hastalar dahil edildi. Hastalarımıza prospektif olarak, objektif testlerden VHIT ve Komputerize Dinamik Posturografi (KDP) uygulanmıştır. Subjektif baş dönmesi verisi olarak da Baş dönmesi Engellilik Envanteri (BEE) ile Vizüel Analog Skala (VAS) skorlaması uygulanmıştır. Bulgular: VOR kazançları verilerinin iki grup arasında uyumlu olduğu görüldü. Operasyon tarafı ve operasyonun karşı taraf arasında anlamlı fark saptandı. Opere taraftaki VOR kazancı verileri ile KDP medial-lateral vestibüler verileri ile zayıf pozitif bir korelasyon saptandı. Opere tarafta, özellikle lateral kanalda covert varlığı %89a ve overt sakkad varlığı %100 gibi yüksek yüzdelere ulaşmaktadır. Opere tarafta her iki sakkad varlığı, operasyonun karşı taraf ile arasında ise anlamlı fark tespit edildi. Ayrıca opere olan taraftaki sakkadların organize olup olmamasının BEE de sınırda anlamlı farklılaşmaya sebep olduğu tespit edildi. Sakkadların amplitüdlerinde artış ise KDP vestibüler verileri arasında negatif zayıf bir korelasyon saptandı. Her iki operasyon grubunda KDPde medial-lateral bulgularının anterior-posterior bulgularına göre daha fazla etkilenmiş olduğu istatistiksel olarak anlamlı bulundu. Buna ek olarak vestibüler nörektomi grubunun KDP de somatosensöriyel skorlama verileri daha düşük olmasına karşın vestibüler skorlama verileri daha yüksek tespit edilmiştir. Yine BEE verileri de nörektomi grubunda daha iyi aralıkta olduğu görülmüştür. Hastalıklar özelinde ise preoperatif hissedilen baş dönmesi açısından Vizüel Analog Skor (VAS)'da Meniere grubu, labirenti destrükte eden kolesteatom grubuna kıyasla daha yüksek olduğu görülmüştür. Sonuç: VHIT testi sonuçlarının değerlendirilmesinde, VOR kazancına ek olarak sakkadların varlığı, latans ve amplitüd verileri ek bilgiler sunmaktadır. Bunları özellikle lateral kanal sonuçlarının daha iyi yansıttığı düşünülmektedir. Vestibüler deafferasyon operasyonlarında medial-lateral vestibüler bulgular, anterior-posterior vestibüler bulgulara kıyasla daha fazla etkilenmekte ve vestibüler nörektomi grubunun total labirentektomi grubuna kıyasla vestibüler skorlar ve BEE skorları daha iyi olmaktadır.Objective: to evaluate the effects of vestibular neurectomy and total labyrinthectomy surgical interventions on vestibulo-ocular reflex (VOR) and central compensation with objective and subjective tests. As a secondary output, it is aimed to determine whether there are parameters which can be used in addition to VOR gain in Video Head Impulse Test (VHIT) in vestibular deafference cases. It is also contemplated to share our clinical experience with the literature. Materiels and Methods: 19 vestibular neurectomy and 18 total labyrinthectomy patients who had undergone previous operations in our clinic and who had past at least one year after the operation were included in the study. Prospectively, VHIT and Computurized Dynamic Posturography (CDP) objective tests were administered to these patients. Dizziness Handicap Inventory (DHI) and Visual Analogue Scale (VAS) scoring were also applied as subjective dizziness test. Results: VOR gain results were found to be compatible between the two groups. There was a significant difference between the operation side and the opposite side of the operation. There was a weak positive correlation between the VOR gain on the opere side and the CDP medial-lateral vestibular data. On the operation side, especially in the lateral canal, the covert saccade presence reached to 89% and the overt saccade presence reached to 100%. There was a significant difference between the saccade presence on the operation side and the opposite side of the operation. It was also found that, on the side of the operation side, whether or not the saccades form organization pattern caused a slight significant differentiation in DHI. An increase in the amplitudes of the saccades showed a weak negative correlation between the CDP vestibular data. It was statistically significant that the medial-lateral data of CDP were more affected than the anterior-posterior data in both operation groups. In addition, although vestibular neurotomy group had lower somatosensory scoring data in CDP, vestibular scoring data were found to be higher. DHI data were also found to be better in the neurectomy group. In terms of preoperative dizziness, the visual analog scale (VAS) score of the Meniere group was found to be higher than the labyrinth destroying cholesteatoma group. Conclusion: In assessing the results of the VHIT test, addition to VOR gain, the presence of saccades, latency and amplitude data provide additional information. These data are thought to be better reflected especially in the lateral canal results. In vestibular deafferation operations, medial-lateral vestibular results are more affected than anterior-posterior vestibular results. In addition, the vestibular scores and DHI scores are better in vestibular neuroctomy group than the total labyrinthectomy group
13.05.1989 töreninde meslekte 40 daha çok yıl ve hizmet onur ödülü alanlar
Full text linkK.AZADE SUCUOĞLU (1947)AHMET ÇIVGINALİ BAĞDATLIOĞLUAHMET KIRLI (1947)ABDİ ATAMER (1936)ASİYE YETKİN (1948)AYSEL UMUR (1949)AKİF ŞAKİROĞULLARI (1949)ABDÜLREZZAK TUĞCU (1949)ABDULLAH GEVGELİ (1949)AHMET YAĞIZTÜRK (1937)ALİ DEMİRALP (1945)BEDRETTİN TEKİNBESİM AKINAYBEDRİ SAATÇİ (1948)BASRİ GÜRKANBEHÇET KALAYCIOĞLU (1949)BEDIA TÜZÜNCEMAL ALPMAN (1935)CEVDET ARUN (1936)CİHAT ARBEK (1941)H.CAHİT TEZER (1942)CELAL ÇAVDAROĞLU (1948)ÇETİN YILMAZ (1949)CEMALETTİN GÜVENDİK (1947)ERTUĞRUL GÜNIŞIK (1939)EMEL GÖKÇEN (1949)EMİN SEYMEN (1936)ENVER GÖZÖRENFAİK GÖKAY (1936)FAHAMET HUMBARACI (1942)FERİDE EROL (1949)FARUK YURTCANLI (1939)GÜLTEKİN ÇEKİ (1949)GÜZİN ÇABUKELLİLER (1949)HAYRİYE SÜĞLÜNHANDAN ÖRS (1938)HÜSEYİN FIRAT (1949)HAŞAN ÖNENHATİCE GÜVENCİK (1948)İBRAHİM KESKİNKAYA (1947)İBRAHİM MENTEŞ (1947)İBRAHİM İŞLERİBRAHİM AKMA
Author Correction: A new ape from Türkiye and the radiation of late Miocene hominines
No full textCorrection to: Communications Biology, published online 23 August 2023. In the original version of the Article, two authors and their affiliations were omitted. In the original version of the Article, author first names were not provided for all authors. The corrected author list and affiliations are provided below. This has now been corrected in the HTML and PDF versions of the article. Ayla Sevim-Erol1, David R. Begun2, Alper Yavuz3, Erhan Tarhan4, Çilem Sönmez Sözer1, Serdar Mayda5, Lars W. van den Hoek Ostende6, Robert M. G. Martin2 ; M. Cihat Alçiçek7 1 Ankara University, Faculty of Languages History and Geography, Department of Anthropology, Ankara, Türkiye 2 Department of Anthropology, University of Toronto, Toronto, ON, Canada 3 Mehmet Akif Ersoy University of Science and Letters, Department of Anthropology, Burdur, Türkiye 4 Hitit University Faculty of Science and Letters, Department of Anthropology, Çorum, Türkiye 5 Ege University Fakulty of Science, Department of Biology, İzmir, Türkiye 6 Naturalis Biodiversity Center, Leiden, The Netherlands 7 Pamukkale University, Department of Geology, 20070 Denizli, Türkiye The Author Contributions section should read “A.S.E. is the PR of the project, secured funding for excavations and lab analysis and directed excavations. A.S.E. and D.R.B. are responsible for data curation, acquired funding and supervised research. D.R.B. conceptualized the analysis, conducted the investigation, developed the methodology, prepared the original draft and all subsequent versions. C.S.S., S.M., L.W.vdH. and C.A. contributed their analysis of geological and paleontological results. R.M.G.M. was responsible for the segmentation and analysis of the scans of the mandible. A.Y and E.T. participated in the excavations.” This has now been corrected in the HTML and PDF versions of the article. © 2023, Springer Nature Limited
Al-Si alaşımı dökümlerinde kalıp türü ve basınç değişiminin mekanik özelliklere etkilerinin araştırılması / The Research of the effects on modification the kinds of mold and pressure on mechanical properties in Al-Si alloy casts
No full textTURKEY’S KURDISH QUESTION: OPPORTUNITIES AND PREDICAMENTS
Full text linkSince the foundation of the Republic of Turkey, the Kurdish question has been the biggest ethnic issue of Turkey which became one of the important subjects in the agenda of Turkey and international organizations. The question has certain impacts on the stability of the country that is today being associated with security and terror issues. Consequently the Kurdish question challenges the state and the country in the aspects of ethnic problems, human rights, democracy, as well as socio-economic and political. The aim of this article is to uncover how the Kurdish question challenges the stability in terms of Turkish state and the Kurds. In this regard, the research engages several objectives; evaluations of approaches toward Kurdish issue, analyzing historical background, and evaluation of the issue in the present time. Research methods of the paper consists of comparative analysis of decision, document analysis on the reports and agreements, descriptive method on the developments, and media analysis to engage relevant news. The main results of the research are concluded on variety aspects of the Kurdish question, such as security, terrorism, minority issue, human rights, and so on. Thus, it creates certain impacts on the stability in Turkey both in terms of state and the Kurds regionally and internationally.Key words: Turkey, Kurds, PKK, Ocalan, AKPJEL CODES: K1, D74, D78doi: http://dx.doi.org/10.15181/rfds.v31i2.209
Complementary Square Ring Resonator Loaded MIMO Antenna Design for 5G NR n258 Frequency Band|5N YR n258 Frekans Bandi I in Tamamlayici Kare Halka Rezonat r Y kl MIMO Anten Tasarimi
No full text33rd IEEE Conference on Signal Processing and Communications Applications, SIU 2025 -- -- Istanbul; Isik University Sile Campus -- 211450Considering the current trajectory of telecommunications, it is evident that 5G NR frequencies and related research in these bands will guide future 6G studies. The n258 (24.25 - 27.50 GHz) band, which falls within the 5G NR FR2 frequency range, is evaluated within this context. In this study, initially, a microstrip patch reference antenna design was addressed and configured to operate within the relevant band. Additionally, a MIMO antenna unit cell design was achieved by integrating a complementary square ring resonator structure into the antenna design. The efficiency of the proposed metasurface within the n258 band was demonstrated, and its impact on the unit cell was presented. The unit cell antenna design achieved a bandwidth of 1.88 GHz and a return loss value of -39.63 dB at the center frequency of 26.08 GHz. Based on the unit cell design, a 2×2 MIMO antenna design was developed. The designed MIMO antenna exhibits a bandwidth of 1.95 GHz and a return loss value of -48.58 dB at the center frequency of 26.09 GHz. © 2025 Elsevier B.V., All rights reserved.Isik Universit
Investigation of the relationship between social study teachers' tendencies and democratic attitudes
No full textEğitimin nitelikli insan gücü ihtiyacını karşılama misyonundan hareketle düşünüldüğünde, buna bağlı olarak istenen düzeyde sorgulama yapan, eleştirel düşünen, araştıran, aktif ve sorumluluk sahibi bireyler yetiştirmek gerekir. Böyle bir görevi üstlenen siyasal yapı, eğitim ve öğretim, eğitim politikaları ve uygulamalarını da doğrudan şekillendiren en üst merci konumundadır. Yetiştirilmek istenen insan tipi, çağın ve ülkenin ihtiyaçlarına karşılık verebilecek yönde olmalı, kişilerin bireysel istek ve ihtiyaçları da önem arz etmelidir. Tüm bunlarla birlikte bir ülkenin vazgeçilmez unsurlarından birisi olan demokrasi kavramı ve demokratik tutumun da yetiştirilen bireylere sağlıklı bir şekilde aktarılması oldukça önemlidir. Milli Eğitimin temel eğitim politikası bunu açıkça ortaya koyar ve bu istikamette yeni nesiller yetiştirilmeye çalışılır. Bu araştrmanın amacı sosyal bilgiler öğretmen adaylarının eleştirel düşünme eğilimleri ile demokratik tutumları arasındaki ilişkinin incelenmesi ve elde edilen bulguların sunulmasıdır. İlişkisel tarama modeli çerçevesinde gerçekleştirilecek araştırmanın örneklemini İstanbul Üniversitesi, Marmara Üniversitesi ve Yıldız Teknik Üniversitesi’nde ilgili bölümlerde öğrenim gören 250 sosyal bilgiler öğretmen adayı oluşturacaktır. Verilerin toplanmasında araştırmacı tarafından oluşturulacak Kişisel Bilgi Formu ve Semerci (2016) tarafından geliştirilen Eleştirel Düşünme Eğilimi (EDE) Ölçeği ve Demokratik Tutum Ölçeği kullanılacaktır. Anketler katılımcılara yüz yüze görüşülerek ve online şekilde uygulanacaktır. Tüm soruları eksiksiz doldurmaları istenecektir. Niceliksel verilerin karşılaştırılmasında iki grup durumunda, normal dağılım gösteren parametrelerin gruplar arası karşılaştırmalannda Bağımsız örnekler (îndependent samples) t testi, niceliksel verilerin karşılaştırılmasında ikiden fazla grup durumunda, normal dağılım gösteren parametrelerin gruplar arası karşılaştırmalannda Tek yönlü (One way) Anova testi ve farklılığa neden olan grubun tespitinde Tukev testi kullanılacaktır. Ölçekler arasındaki ilişkinin tespit edilmesinde korelasyon analizi uygulanacaktır. Sonuçlar % 95 güven aralığında, p<0,05 anlamlılık düzeyinde değerlendirilecektir. Araştırmanın ilgili literatüre katkı sunması ve daha sonra yapılacak araştırmalara ışık tutması beklenmektedir.Considering the mission of meeting the qualified manpower need of education, accordingly, it is necessary to raise individuals who question, think critically, research, and are active and responsible at the desired level. The political structure that undertakes such a task is the highest authority that directly shapes education and training, education policies and practices. The type of person to be raised should be able to respond to the needs of the age and the country, and the individual wishes and needs of the people should also be important. In addition to all these, it is very important to transfer the concept of democracy and democratic attitude, which is one of the indispensable elements of a country, to the grown individuals in a healthy way. The basic education policy of the National Education clearly reveals this, and new generations are tried to be raised in this direction. The surveys will be administered to the participants by face-to-face interviews and online. They will be asked to fill in all the questions completely. In the case of two groups in the comparison of quantitative data, independent samples t-test in the comparison of the parameters with normal distribution between the groups, in the case of more than two groups in the comparison of quantitative data, in the comparison of the parameters with normal distribution between the groups, the One-way Anova test and the difference-causing Anova test. Tukev test will be used to determine the group. Correlation analysis will be applied to determine the relationship between the scales. The results will be evaluated at the 95% confidence interval, at the p<0.05 significance level. It is expected that the research will contribute to the relevant literature and shed light on future research
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