323,151 research outputs found
Measurement and comparison of complex impedance of silicon p-i-n photodiodes at different temperatures
No full textWOS: 000244892700020The dark alternating current (ac) parameters of BPW34 and BPW41 (Vishay-Telefunken) silicon p-i-n photodiodes arc measured and compared at different temperatures using the impedance spectroscopy technique. The impedance plots are nearly semicircular and typically distorted on the high frequency side. For BPW41, the distortion apparently arises from one of the two interfaces as expected for a typical p-i-n device. However, for BPW34, the presence of the distortion is attributed to the variation of photodiode capacitance and resistance with measurement frequency
Hibrit Kontrol Ünitesi Tasarımında Giriş ile Çıkışların Belirlenmesi ve Bulanık Mantık Kontrolörün Oluşturulması
No full textArıkuşu, Y., S., Kazaklı, M., K., İn, S., Bayhan, N., Tiryaki, H. (2020). Hibrit Kontrol Ünitesi Tasarımında Giriş ile Çıkışların Belirlenmesi ve Bulanık Mantık Kontrolörün Oluşturulması,Bilim, Teknoloji ve Mühendislik Araştırmaları Dergisi,1 (1),19-24Bu çalışma TÜBİTAK ARDEB Mühendislik Araştırma Grubu tarafından 216M252 numaralı 1003 projesiyle desteklenmiştir. Ayrıca bu çalışma İstanbul Üniversitesi – Cerrahpaşa, Bilimsel Araştırma Projeleri Koordinasyon Birimi tarafından desteklenmiştir. Proje numarası: 3341
AI-Empowered Software-Defined WLANs
Get PDFThe complexity of wireless and mobile networks is growing at an unprecedented pace. This trend is proving current network control and management techniques based on analytical models and simulations to be impractical, especially if combined with the data deluge expected from future applications such as augmented reality. This is particularly true for software-defined wireless local area networks (SO-WLANs). It is our belief that to battle this growing complexity, future SO-WLANs must follow an artificial intelligence (AI) -native approach. In this article, we introduce aiOS, which is an AI-based platform that builds toward the autonomous management of SD-WLANs. Our proposal is aligned with the most recent trends in in-network AI promoted by the ITU Telecommunication Standardization Sector (ITU-T) and with the architecture for disaggregated radio access networks promoted by the Open Radio Access Network Alliance. We validate aiOS in a practical use case, namely frame size optimization in SD-WLANs, and we consider the long-term evolution, challenges, and scenarios for AI-assisted network automation in the wireless and mobile networking domain
Conduction Mechanism of an Infrared Emitting Diode: Impedance Spectroscopy and Current-Voltage Analysis
No full textWOS: 000301787800024The bias dependent complex impedance spectra of a conventional GaAs based infrared emitting diode have been studied in the temperature range 150-300 K. It is found that for bias voltages lower than 0.7 V, the device behaves like a pure capacitor. However for V-dc >= 0.7 V, an equivalent circuit model composed of a parallel resistor (R-p) and capacitor (C-p) network connected with a series resistance (R-s) can be used to describe the individual impedance contributions from interfacial and bulk regions of the diode. Fitting of experimental data to the proposed ac model reveal that the value of parallel device capacitance C-p increases with temperature whereas the parallel resistance R-p component decreases. The tendency of parallel resistance and parallel capacitance as a function of temperature is expected that thermally activated current transport mechanism dominates in the forward bias, which coincides with the analysing results of the dark forward current-voltage (I-V) characteristics. The temperature dependent I-V variations suggest that recombination in the depletion region has a paramount role
Diffusive author(s), cohesive author: Analysis of S/N (1994)
No full textThis study indicates the ways in which various aspects of the author(s) are brought forth in Dumb type’s performance art, the S/N production. Previous research has suggested a non-hierarchical organization of Dumb type and the absence of a “privileged author” in Dumb type’s collaborative work, S/N. However, the results that I have investigated from member’s interviews on the creative process of S/N along with my analysis of the recorded images of S/N, indicate a different aspect of the author(s). First, S/N was created through, so to speak, the collective ideas of the members of Dumb type. Further, S/N has at least nine quotations from previous performances, installations, and printed writings, besides the work-in-progress technique. Explicating one of the “author functions” as given by Michel Foucault, each text has plural subjects of the author. However, it has been revealed from members’ interviews that Teiji Furuhashi had a decision-making role in selecting the members’ ideas within the performance. Since then, S/N has had plural subjects of creation; however, Furuhashi is one of the subjects of creation along with the “privileged author.” S/N has plural authors (diffusive authors) yet at the same time, it has a “privileged author,” Teiji Furuhashi (cohesive author)
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Miliary tuberculosis disease complicated by Pott′s abscess in an infant: Seven year follow-up
No full textA 20-month-old boy presented with 1-year history of persistent fever, cough, and progressive abdominal distention. Abdominal ultrasonography showed hepatomegaly and multiple calcifications in the liver and spleen. Thoracic computed tomography showed multiple mediastinal lymph nodes and consolidation in both lungs. Additionally, there was a 2-cm thick retroperitoneal soft tissue mass destroying the T7-8 and L1-L2 vertebral bodies. The patient was preliminarily diagnosed with miliary tuberculosis (TB) and Pott′s disease, and began administering anti-TB treatment consisting of isoniazid, rifampin, ethambutol, and pyrazinamide. Acid-resistant bacilli analysis and mycobacterial culture of the biopsy specimen of Pott′s abscess were positive. Mycobacterial culture and PCR of gastric aspirate were also positive. The patient′s condition progressively improved with anti-TB treatment and he received 12 months of antiTB therapy. At the end of the treatment all of the patient′s symptoms were relieved and he was well except for kyphosis. Miliary TB complicated by Pott′s abscess is a very rare presentation of childhood TB. The presented case shows that when Pott′s abscess is diagnosed and surgically corrected without delay, patients can recover without squeal
Study of CdS/Cu(In,Ga)Se-2 interface by using n values extracted analytically from experimental data
No full textBayhan, Habibe/0000-0001-7792-0305WOS: 000264089800011This paper presents that in analytical method based on Lambert W-function can be applied to estimate the value of the diode ideality factor n, of a ZnO/CdS/Cu(In,Ga)Se-2 (CIGS) solar cell by using its dark current-voltage characteristics. The method is tested at different temperatures in the dark and found that the resulting n(T) values are in good agreement with those estimated experimentally from the slopes of the straight-line regions of Log I-V plots. The suggested values of n(T) under illumination are also determined using the exact explicit analytic solutions for the current-voltage relation expressed in terms of Lambert W-functions and experimentally estimated parasitic series and shunt resistances (R-s, R-sh), diode saturation current (I-o), open circuit voltage (V-oc) and short circuit current (I-sc) values at various temperatures. Temperature dependence of the diode ideality factor revealed that after illumination still tunnelling enhanced interface recombination mechanism dominates the Current transport with relatively low tunnelling energy as compared to the dark case. (c) 2008 Elsevier Ltd. All rights reserved
A comparison of the effect of CdCl2 and MgCl2 processing on the transport properties of n-CdS/p-CdTe solar cells and a simple approach to determine their back contact barrier height
Get PDFA simple approach, which can estimate the barrier height of non-Ohmic back contacts for CdS/CdTe solar cell by using its temperature dependent forward biased current-voltage data, is explained. The method involves modelling the forward J–V characteristics using a double exponential expression for the main junction and by a reverse biased Schottky barrier for the back contact. Cells processed with both CdCl2 and MgCl2 are compared, with the current transport phenomena in both kinds of cells also being analysed. Performance loss due to limitation of the forward bias hole current, and its dependence on the post-deposition chloride processing, is discussed. The forward current transport is mainly dominated by recombination at CdS/CdTe interfacial region with pronounced tunnelling effects. Classical Schottky-type conduction, as described by the Richardson-Schottky formula, is a good fit to the reverse biased current-voltage behaviour of an Au/CdTe junction above ∼240 K. Below this temperature, the current limiting effect due to the increasing contribution from interfacial defect states can be satisfactorily explained by Bardeen’s model for a modified Schottky type barrier at back contact interface
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