Publications without Fulltext
Permanent URI for this collectionhttps://hdl.handle.net/20.500.14288/3
Browse
128 results
Filters
Advanced Search
Filter by
Settings
Search Results
Publication Metadata only A physical channel model for nanoscale neuro-spike communications(IEEE-Inst Electrical Electronics Engineers Inc, 2013) Balevi, eren; Department of Electrical and Electronics Engineering; Akan, ĆzgĆ¼r BarıÅ; Faculty Member; Department of Electrical and Electronics Engineering; College of Engineering; 6647Nanoscale communications is an appealing domain in nanotechnology. Novel nanoscale communications techniques are currently being devised inspired by some naturally existing phenomena such as the molecular communications governing cellular signaling mechanisms. Among these, neuro-spike communications, which governs the communications between neurons, is a vastly unexplored area. The ultimate goal of this paper is to accurately investigate nanoscale neuro-spike communications characteristics through the development of a realistic physical channel model between two neurons. The neuro-spike communications channel is analyzed based on the probability of error and delay in spike detection at the output. The derived communication theoretical channel model may help designing novel artificial nanoscale communications methods for the realization of future practical nanonetworks, which are the interconnections of nanomachines.Publication Metadata only Application QoS fairness in wireless video scheduling(Institute of Electrical and Electronics Engineers (IEEE), 2006) N/A; N/A; Department of Electrical and Electronics Engineering; Department of Electrical and Electronics Engineering; Department of Electrical and Electronics Engineering; ĆzƧelebi, Tanır; Tekalp, Ahmet Murat; Civanlar, Mehmet Reha; Sunay, Mehmet OÄuz; PhD Student; Faculty Member; Faculty Member; Faculty Member; Department of Electrical and Electronics Engineering; Graduate School of Sciences and Engineering; College of Engineering; College of Engineering; College of Engineering; N/A; 26207; 16372; N/AThe video pre-roll delay for filling up the client buffer can not be too long for user utility and buffer limitations in wireless point-to-multipoint streaming systems. Cross-layer design that deals with both physical and application layer aspects jointly is necessary for this purpose. We present a cross-layer optimized multiuser video adaptation and user scheduling framework for wireless video communication, where Quality-of-Service (QoS) fairness among users is provided with maximum video quality and video throughput. Both protocol layers are jointly optimized using a single Multi-Objective Optimization (MOO) framework that aims to schedule the user with the least remaining playback time and the highest video throughput (delivered video seconds per transmission slot) with maximum video quality. Experiments carried out in the IS-856 (1ĆEV-DO) standard and ITU pedestrian and vehicular environments demonstrate the improvements over the state-of-the-art schedulers in terms of video QoS fairness, video quality and throughput. / Ä°stemci arabelleÄini doldurmak iƧin videodan ƶnce gƶsterilen reklam gecikmesi, kablosuz noktadan Ƨok noktaya akıŠsistemlerinde kullanıcı yardımcı programı ve arabellek sınırlamaları iƧin Ƨok uzun olamaz. Bu amaƧ iƧin hem fiziksel hem de uygulama katmanı ƶzelliklerini birlikte ele alan Ƨapraz katman tasarımı gereklidir. Kablosuz video iletiÅimi iƧin, kullanıcılar arasında Hizmet Kalitesi (QoS) adaletinin maksimum video kalitesi ve video ƧıkıÅı ile saÄlandıÄı, katmanlar arası optimize edilmiÅ Ć§ok kullanıcılı bir video uyarlaması ve kullanıcı planlama ƧerƧevesi sunuyoruz. Her iki protokol katmanı, kullanıcıyı maksimum video kalitesiyle en az kalan oynatma sĆ¼resi ve en yĆ¼ksek video verimi (iletim yuvası baÅına iletilen video saniyesi) ile programlamayı amaƧlayan tek bir Ćok AmaƧlı Optimizasyon (MOO) ƧerƧevesi kullanılarak ortaklaÅa optimize edilmiÅtir. IS-856 (lxEV-DO) standardında ve ITU yaya ve araƧ ortamlarında gerƧekleÅtirilen deneyler, video QoS adaleti, video kalitesi ve verim aƧısından en son teknoloji zamanlayıcılara gƶre iyileÅtirmeler gƶstermektedir.Publication Metadata only Opportunities and challenges of MOF-based membranes in gas separations(Elsevier, 2015) Avci, Ahmet K.; N/A; Department of Chemical and Biological Engineering; Adatoz, Elda Beruhil; Keskin, Seda; PhD Student; Faculty Member; Department of Chemical and Biological Engineering; Graduate School of Sciences and Engineering; College of Engineering; N/A; 40548Gas separation using metal organic framework (MOF) membranes has become an increasingly important research field over the last years. Several recent studies have shown that thin-film MOF membranes and MOF/polymer composite membranes can outperform well known polymer and zeolite membranes in various gas separation applications. The continuously increasing number of experimental and computational studies emphasizes the superior membrane properties of MOFs. In this review, we present a summary of experimental and computational studies both for thin-film MOF membranes and MOF/polymer composite membranes. We aim to address opportunities and challenges related with use of MOF membranes for gas separations as well as give directions on the requirements for employing these membranes in practical applications. (C) 2015 Elsevier B.V. All rights reserved.Publication Metadata only Mesoporous graphitic carbon nitride-supported binary MPt (M: Co, Ni, Cu) nanoalloys as electrocatalysts for borohydride oxidation and hydrogen evolution reaction(Elsevier, 2020) Oliveira, Raisa C. P.; Sevim, Melike; Sljukic, Biljana; Sequeira, Cesar A. C.; Santos, Diogo M. F.; Department of Chemistry; Metin, Ćnder; Faculty Member; Department of Chemistry; College of Sciences; 46962In this work, binary MPt (M = Co, Ni, Cu) nanoalloys and mesoporous carbon nitride (mpg-C3N4) as support material are prepared, and then gathered together by liquid phase self-assembly in order to produce MPt/mpg-C3N4 electrocatalysts. The yielded electrocatalysts are characterized by TEM, ICP-MS and XRD techniques in order to determine their morphology, composition and textural properties. Evaluation of MPt/mpg-C3N4 (<3 wt.% of Pt) electrocatalysts performance for hydrogen evolution reaction (HER) and borohydride oxidation reaction (BOR) is carried out. Pt/mpg-C3N4 is also studied to better understand the alloying effect on the electrocatalysts' performance, being concluded that it clearly increases the catalytic activity while decreasing the necessary Pt metal amount. For HER, CoPt/mpg-C3N4 was found to be the best catalyst, presenting a Tafel slope of 109 mV dec(-1) at 65 degrees C. Regarding BOR, CuPt/mpg-C3N4 demonstrated the best catalytic activity with average activation energy and reaction order with respect to BH4- of 29.4 kJ mol(-1) and 0.87, respectively.Publication Metadata only Dynamic analysis of a novel moving magnet linear actuator(IEEE-Inst Electrical Electronics Engineers Inc, 2017) N/A; N/A; N/A; Department of Mechanical Engineering; Hassan, Adnan; Bijanzad, Armin; LazoÄlu, Ä°smail; PhD Student; PhD Student; Faculty Member; Department of Mechanical Engineering; Graduate School of Sciences and Engineering; Graduate School of Sciences and Engineering; College of Engineering; N/A; N/A; 179391A novel moving magnet linear actuator is proposed for linear oscillations in the linear resonant compressors for household refrigerators. This paper provides stator and armature design including CAD model and geometric parameters. Furthermore, the working principle of the proposed actuator is explained. The stator assembly is composed of two reversely wound coils, which are electrically excited with single phase ac power and oscillates the radially magnetized armature. With the help of the electromechanical analytical model, the dynamic parameters such as stroke, velocity, and acceleration of the armature are derived. Additionally, the time-dependent current model of the stator winding is proposed. An experimental setup is used to validate these responses at the resonance excitation frequency with the help of sensors. The system kinetics are discussed to estimate the spring, damping, inertial, and magnetic forces. A simulation is executed to estimate the time-domain responses of these dynamic parameters and the effects of excitation frequency are discussed. The force models are experimentally validated at the resonance frequency excitation. In order to evaluate the performance of the proposed actuator, a comparison of the performance parameters, such as efficiency, stroke, current, and mass flow rate is demonstrated with the conventional rotary as well as the linear motors for linear compressor application.Publication Metadata only Second language tutoring using social robots: a large-scale study(Institute of Electrical and Electronics Engineers (IEEE), 2019) Vogt, Paul; van den Berghe, Rianne; de Haas, Mirjam; Hoffman, Laura; Montanier, Jean-Marc; Oudgenoeg-Paz, Ora; Garcia, Daniel Hernandez; Papadopoulos, Fotios; Schodde, Thorsten; Verhagen, Josje; Wallbridge, Christopher D.; Willemsen, Bram; de Wit, Jan; Belpaeme, Tony; Kopp, Stefan; Krahmer, Emiel; Leseman, Paul; Pandey, Amit Kumar; Department of Psychology; Department of Psychology; Department of Psychology; Department of Psychology; Department of Psychology; Gƶksun, Tilbe; Kanero, Junko; KĆ¼ntay, Aylin C.; MamuÅ, AyÅe Ezgi; OranƧ, Cansu; Faculty Member; Researcher; Faculty Member; Researcher; Researcher; Department of Psychology; College of Social Sciences and Humanities; College of Social Sciences and Humanities; College of Social Sciences and Humanities; College of Social Sciences and Humanities; College of Social Sciences and Humanities; 47278; N/A; 178879; N/A; N/AWe present a large-scale study of a series of seven lessons designed to help young children learn English vocabulary as a foreign language using a social robot. The experiment was designed to investigate 1) the effectiveness of a social robot teaching children new words over the course of multiple interactions (supported by a tablet), 2) the added benefit of a robot's iconic gestures on word learning and retention, and 3) the effect of learning from a robot tutor accompanied by a tablet versus learning from a tablet application alone. For reasons of transparency, the research questions, hypotheses and methods were preregistered. With a sample size of 194 children, our study was statistically well-powered. Our findings demonstrate that children are able to acquire and retain English vocabulary words taught by a robot tutor to a similar extent as when they are taught by a tablet application. In addition, we found no beneficial effect of a robot's iconic gestures on learning gains.Publication Metadata only Gap metric concept and implications for multilinear model-based controller design(Amer Chemical Soc, 2003) Galan, O.; Romagnoli, J.A.; Palazoglu, A.; Department of Chemical and Biological Engineering; Arkun, Yaman; Faculty Member; Department of Chemical and Biological Engineering; College of Engineering; 108526The gap metric concept is used within the context of multilinear model-based control. The concept of distance between dynamic systems is used as a criterion for selecting a set of models that can explain the nonlinear plant behavior in a given operating range. The case studies presented include a CSTR and a pH neutralization reactor. The gap metric is used to analyze the relationships among candidate models, resulting in a reduced model set that provides enough information to design multilinear controllers. The simulation and experimental results indicate good performance and stability features.Publication Metadata only Guest editorial special issue on toward securing Internet of Connected Vehicles (IoV) from virtual vehicle hijacking(Institute of Electrical and Electronics Engineers (IEEE), 2019) Cao, Yue; Kaiwartya, Omprakash; Song, Houbing; Lloret, Jaime; Ahmad, Naveed; Department of Electrical and Electronics Engineering; Ergen, Sinem Ćƶleri; Faculty Member; Department of Electrical and Electronics Engineering; College of Engineering; 7211N/APublication Metadata only Analysis and optimization of duty-cycle in preamble-based random access networks(Springer, 2013) Fischione, C.; Park, P.; Department of Electrical and Electronics Engineering; Ergen, Sinem Ćƶleri; Faculty Member; Department of Electrical and Electronics Engineering; College of Engineering; 7211Duty-cycling has been proposed as an effective mechanism for reducing the energy consumption in wireless sensor networks (WSNs). Asynchronous duty-cycle protocols where the receiver wakes up periodically to check whether there is a transmission and the sender transmits preambles to check if the receiver is awake are widely used in WSNs due to the elimination of complex control mechanisms for topology discovery and synchronization. However, the intrinsic simplicity of the asynchronous mechanism has the drawback of smaller energy saving potential that requires the optimization of the duty cycle parameters. In this paper, we propose a novel method for the optimization of the duty-cycle parameters in preamble-based random access networks based on the accurate modeling of delay, reliability and energy consumption as a function of listen time, sleep time, traffic rate and medium access control (MAC) protocol parameters. The challenges for modeling are the random access MAC and the sleep policy of the receivers, which make it impossible to determine the exact time of data packet transmissions, and thus difficult to investigate the performance indicators given by the delay, reliability and energy consumption to successfully receive packets. An analysis of these indicators is developed as a function of the relevant parameters of the network and it is used in the minimization of the energy consumption subject to delay and reliability requirements. The optimization provides significant reduction of the energy consumption compared to the previously proposed protocols in the literature.Publication Metadata only Application of a design methodology using a 2D micro scanner(Taylor & Francis, 2006) Department of Mechanical Engineering; N/A; BaÅdoÄan, Ä°pek; AnaƧ, Ozan; Faculty Member; Master Student; Department of Mechanical Engineering; College of Engineering; Graduate School of Sciences and Engineering; 179940; N/APredicting the performance of Micro Electro Mechanical Systems (MEMS) early in the design phase can impact the design cost and also improve the quality of the design. This paper presents a methodology which aims to predict the performance of such systems under various disturbance sources and develop a generalized design approach for micro structures. A two-dimensional torsional micro scanner mirror was chosen as the case study to demonstrate the developed methodologies. The finite element model (FEM) of the micro mirror was built using ANSYS software. An experimental vibration testing system was built to validate, update, and correct the finite element model. Validated finite element model was used to obtain the state space representation of the mirror. The state space model was used for disturbance analysis which was performed using Lyapunov approach to obtain root-mean-square (RMS) values of the mirror rotation angle under the effect of a disturbance torque. The disturbance analysis framework was combined with the sensitivity analysis to determine the critical design parameters for improving the system performance.