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Permanent URI for this collectionhttps://hdl.handle.net/20.500.14288/3
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Publication Metadata only Multiscale coupling based on quasicontinuum method in nanowires at finite temperatures(IEEE, 2015) Sonne, Mads Rostgaard; Hattel, Jesper Henri; N/A; Department of Mechanical Engineering; Esfahani, Mohammad Nasr; Alaca, Burhanettin Erdem; PhD Student; Faculty Member; Department of Mechanical Engineering; Graduate School of Sciences and Engineering; College of Engineering; N/A; 115108Nanoelectromechanical systems have been developed for ultra-high frequency oscillators because of their small size and excellent material properties. Using flexural modes and electrothermal features in nanowires for frequency tuning necessitates a sound modeling approach. The quasicontinuum method was developed to link atomistic models with the continuum finite element method in order to study the material behavior across multiple length scales. These significant efforts to develop a continuum theory based on atomistic models have so far been limited to zero temperature. The purpose of this work is to develop the theoretical framework needed to study the mechanical response in nanoscale components such as nanowires at finite temperatures. This is achieved up to a temperature of 1000 K by integrating Engineering Molecular Mechanics and the Cauchy-Born hypothesis. The proposed method is verified with Molecular Dynamics and Molecular Mechanics simulations reported in literature. Bending properties of nanowires at finite temperatures were studied with the proposed method. Thermomechanical properties were investigated by including surface effects.Publication Metadata only Through the glance mug: a familiar artefact to support opportunistic search in meetings(Assoc Computing Machinery, 2018) N/A; Department of Psychology; Department of Electrical and Electronics Engineering; N/A; N/A; N/A; Department of Psychology; Department of Media and Visual Arts; Börütecene, Ahmet; Bostan, İdil; Akyürek, Ekin; Sabuncuoğlu, Alpay; Temuzkuşu, İlker; Genç, Çağlar; Göksun, Tilbe; Özcan, Oğuzhan; PhD Student; Undergraduate Student; Undergraduate Student; PhD Student; Researcher; PhD Student; Faculty Member; Faculty Member; Department of Electrical and Electronics Engineering; Department of Psychology; Department of Media and Visual Arts; KU Arçelik Research Center for Creative Industries (KUAR) / KU Arçelik Yaratıcı Endüstriler Uygulama ve Araştırma Merkezi (KUAR); KU Arçelik Research Center for Creative Industries (KUAR) / KU Arçelik Yaratıcı Endüstriler Uygulama ve Araştırma Merkezi (KUAR); N/A; N/A; KU Arçelik Research Center for Creative Industries (KUAR) / KU Arçelik Yaratıcı Endüstriler Uygulama ve Araştırma Merkezi (KUAR); KU Arçelik Research Center for Creative Industries (KUAR) / KU Arçelik Yaratıcı Endüstriler Uygulama ve Araştırma Merkezi (KUAR); N/A; KU Arçelik Research Center for Creative Industries (KUAR) / KU Arçelik Yaratıcı Endüstriler Uygulama ve Araştırma Merkezi (KUAR); Graduate School of Social Sciences and Humanities; College of Social Sciences and Humanities; College of Engineering; Graduate School of Sciences and Engineering; N/A; Graduate School of Social Sciences and Humanities; College of Social Sciences and Humanities; College of Social Sciences and Humanities; N/A; N/A; N/A; N/A; N/A; N/A; 47278; 12532During collocated meetings, the spontaneous need for information, called opportunistic search, might arise while conversing. However, using smartphones to look up information might be disruptive, disrespectful or even embarrassing in social contexts. We propose an alternative instrument for this practice: Glance Mug, A touch-sensitive mug prototype that listens to the conversation and displays browsable content-driven results on its inner screen. We organized 15 pairs of one-to-one meetings between students to gather user reflections. the user study revealed that the mug has the potential for supporting instant search and affords sufficient subtlety to conceal user actions. Yet, it provoked some anxiety for the users in maintaining eye contact with their partners. Our main contributions are the context-aware mug concept tested in a real-life setting and the analysis through Hornecker and Buur's Tangible interaction Framework that discusses its design space, and its impact on the users and social interaction.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; Göksun, Tilbe; Kanero, Junko; Küntay, Aylin C.; Mamuş, Ayşe Ezgi; Oranç, 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 A multi-objective optimization approach for sustainable supply chains incorporating business strategy(IEEE, 2019) N/A; Department of Industrial Engineering; Bozgeyik, Esma Nur; Türkay, Metin; Master Student; Faculty Member; Department of Industrial Engineering; Graduate School of Sciences and Engineering; College of Engineering; N/A; 24956Sustainability is a necessity in the design and operation of supply chains. the triple bottom line (TBL) accounting of sustainability needs to incorporate economic, environmental and social pillars simultaneously in the decision making process. the business strategy can be developed to promote sustained growth, Also incorporating in the supply chain management issues as a business strategy rather than philanthropy. Deciding on the location of business facilities, supplier-manufacturer network, manufacturer-demand location network and the supplier- manufacturer relation strategy are among the important decisions in business strategy and supply chain management. However, there is a lack of theoretical work which analyzes the business strategy together with TBL concept of sustainability for the supply chain network design problem. in this paper, A methodological approach based on mathematical programming is proposed that conforms to the TBL accounting for supply chain network design problem from suppliers to customers embedded with business strategy and green energy usage option. a realistic case study is applied to the model. the results show that working with inclusive suppliers and using green energy are preferred with highest profit value.Publication Metadata only Energy-efficient RF source power control for opportunistic distributed sensing in wireless passive sensor networks(IEEE, 2012) N/A; Department of Electrical and Electronics Engineering; Biçen, Ahmet Ozan; Akan, Özgür Barış; Master Student; Faculty Member; Department of Electrical and Electronics Engineering; Graduate School of Sciences and Engineering; College of Engineering; N/A; 6647Energy limitation of sensor nodes is the main constraint to be addressed while designing and implementing algorithms for wireless sensor networks (WSN). Recently, to mitigate battery depletion problem and extend network lifetime, wireless passive sensor networks (WPSN) have become a new field of interest. Modulated backscattering is an important communication technique for WPSN to enable unlimited lifetime for sensor nodes. Determination of required number and power level of RF sources for wireless power transfer to sensor nodes is crucial for energy-efficient distributed sensing operation. Furthermore, deployed RF sources can share spectrum opportunistically via incorporation of cognitive radio capability such that desired distributed estimation distortion can be achieved with minimum spectrum utilization by WPSN. Employment of RF sources that radiate power only when spectrum opportunities are available unveils passive opportunistic distributed sensing (PODS). in this paper, first, we model intercepted power by passive sensor from RF sources and reflected power by passive sensor at the sink, and effect of opportunistic access to licensed spectrum bands on instantaneous throughput of sensor nodes. then, A power level control scheme for RF sources is proposed to achieve desired distortion level with minimum energy consumption while using opportunistic distributed sensing in WPSN. achieved estimation distortion at sink with respect to number and power level of RF sources, and available spectrum opportunities is investigated, and energy saving provided by proposed power control scheme is assessed for various distortion requirements, channel noise levels, and available spectrum opportunities via simulation experiments.Publication Metadata only Mechanically coupled comb drive MEMS stages(IEEE, 2008) Hedsten, Karin; Enoksson, Peter; Department of Electrical and Electronics Engineering; N/A; Department of Electrical and Electronics Engineering; N/A; Department of Electrical and Electronics Engineering; Arslan, Aslıhan; Ataman, Çağlar; Holmstrom, Sven; Seren, Hüseyin Rahmi; Ürey, Hakan; Researcher; PhD Student; Researcher; Master Student; Faculty Member; Department of Electrical and Electronics Engineering; College of Engineering; Graduate School of Sciences and Engineering; College of Engineering; Graduate School of Sciences and Engineering; College of Engineering; N/A; N/A; N/A; N/A; 8579An electrostatic large clear-aperture in-plane scanner with a novel actuation principle is presented for fast and large stroke scanning applications. 9 pm resonant deflection at 11.51 KHz with 100 Vpp excitation is observed.Publication Metadata only Optimal and efficient distributed online learning for big data(IEEE, 2015) Sayın, Muhammed O.; Vanlı, N. Denizcan; Kozat, Süleyman S.; Delibalta, İbrahim; PhD Student; Graduate School of Social Sciences and Humanities; N/AWe propose optimal and efficient distributed online learning strategies for Big Data applications. Here, we consider the optimal state estimation over distributed network of autonomous data sources. The autonomous data sources can generate and process data locally irrespective of any centralized control unit. We seek to enhance the learning rate through the distributed control of those autonomous data sources. We emphasize that although this problem attracted significant attention and extensively studied in different fields including services computing and machine learning disciplines, all the well-known strategies achieve suboptimal online learning performance in the mean square error sense. To this end, we introduce the oracle algorithm as the optimal distributed online learning strategy. We also propose the optimal and efficient distributed online learning algorithm that reduces the communication load tremendously, i.e., requires the undirected disclosure of only a single scalar. Finally, we demonstrate the significant performance gains due to the proposed strategies with respect to the state-of-the-art approaches.Publication Metadata only E-coach(IEEE, 2004) Department of Electrical and Electronics Engineering; Department of Electrical and Electronics Engineering; Baykan, Eda; Civanlar, Mehmet Reha; Undergraduate Student; Faculty Member; Department of Electrical and Electronics Engineering; College of Engineering; College of Engineering; N/A; 16372We developed the necessary software to control the playback speed of exercise videos playing on a personal computer, using the heart rate of an individual performing the recorded exercise routine. Moderate exercise, At an appropriate heart rate, is widely regarded today as an excellent way to improve one's health when performed on a regular and frequent basis. one popular form of an indoor exercise program is to use a video "workout" program of aerobic exercise and/or weight training exercises. the "off-the-shelf" exercise videos, while they may target various fitness levels (such as "beginner", "regular", and "advanced"), cannot offer precise adjustments to address each user's current fitness level. the software developed allows for the playback of an exercise video to be adjusted to accommodate the fitness level of the individual user through a closed loop feedback mechanism. the project is being improved for logging and analyzing the performance of an individual who uses the system regularly and for exercise planning. the closed loop feedback mechanism that models the relationship between the heart rate and exercise level, is being improved with the experiments in which subjects incude fit people as well as ones who are sedementary./ Öz: Bu çalışmada bilgisayarda gösterilen bir egzersiz videosundaki hareketleri yapan insanın kalp atış hızını kullanarak, videonun oynatılma hızını değiştiren hir yazılım geliştirildi. Uygun kalp hızında, düzenli ve sık yapılan egzersizler sağlıklı bir yaşam için çok önemlidir. Video eşliğinde yapılan aerobik ve ağırlık kaldırma çalışmaları kapalı alan egzersizlerinin popiler çeşitlerindendir. Egzersiz videoları başlangıç-orta-ileri gibi çalışma seçenekleri sunsa da her bireyin farklı olan metabolizma hızına ve sportif yapısına hitap edemez. Geliştirdiğimiz yazılım, geri beslemeli denetim mekanizmasını kullanarak video hızının, spor yapan insanin kalp atış hızına göre degişmesini sağlamaktadir. Sistem diizenli olarak kullanan bireylerin performanslarını kaydetmek ve incelemek için de geliştirilmektedir. Düzenli spor yapan ve yapmayan bireyler üzerinde yapılan deneylerle, kalp atış hızı ile egzersiz seviyesi arasındaki ilişkiyi modellyen geri beslemeli denetim mekanizması geliştirilmektedir.Publication Metadata only Ransac-based training data selection for speaker state recognition(Isca-Int Speech Communication Assoc, 2011) Erdem, Çiğdem Eroğlu; Erdem, A. Tanju; N/A; Department of Computer Engineering; Bozkurt, Elif; Erzin, Engin; PhD Student; Faculty Member; Department of Computer Engineering; Graduate School of Sciences and Engineering; College of Engineering; N/A; 34503We present a Random Sampling Consensus (RANSAC) based training approach for the problem of speaker state recognition from spontaneous speech. Our system is trained and tested with the INTERSPEECH 2011 Speaker State Challenge corpora that includes the Intoxication and the Sleepiness Sub-challenges, where each sub-challenge defines a two-class classification task. We aim to perform a RANSAC-based training data selection coupled with the Support Vector Machine (SVM) based classification to prune possible outliers, which exist in the training data. Our experimental evaluations indicate that utilization of RANSAC-based training data selection provides 66.32 % and 65.38 % unweighted average (UA) recall rate on the development and test sets for the Sleepiness Sub-challenge, respectively and a slight improvement on the Intoxication Sub-challenge performance.Publication Metadata only Using rattling ions to probe SUB-PS water network dynamics(IEEE, 2010) Schmidt, Diedrich A.; Funkner, Stefan; Born, Benjamin P.; Gnanasekaran, Ramachandran; Schwaab, Gerhard W.; Leitner, David M.; Havenith, Martina; N/A; Birer, Özgür; Researcher; Koç University Surface Science and Technology Center (KUYTAM) / Koç Üniversitesi Yüzey Teknolojileri Araştırmaları Merkezi (KUYTAM); N/A; N/AWe present THz measurements on fifteen solvated alkali halide salts using narrow band THz absorption and broad band THz Fourier transform spectroscopies in order to shed new light on the controversy of salts as kosmotropes (structure breakers) or chaotropes (structure makers). © 2010 IEEE.