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Permanent URI for this collectionhttps://hdl.handle.net/20.500.14288/3
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Publication Metadata only End-to-end deep multi-modal physiological authentication with smartbands(IEEE-Inst Electrical Electronics Engineers Inc, 2021) Ekiz, Deniz; Dardağan, Yağmur Ceren; Aydar, Furkan; Köse, Rukiye Dilruba; Ersoy, Cem; N/A; Can, Yekta Said; Researcher; College of Social Sciences and Humanities; N/AThe number of fitness tracker users increases every day. Most of the applications require authentication to protect privacy-preserving operations. Biometrics such as face images have been used widely as login tokens, but they have privacy issues. Moreover, occlusions like face masks used for COVID may reduce their effectiveness. Smartbands can track heart rate, movements, and electrodermal activities. They have been widely used for health-related applications. The use of smartbands for authentication is in the exploratory stage. Physiological signals gathered from smartbands may be used to create a multi-modal and multi-sensor authentication system. The popularity of smartbands enables us to deploy new applications without a need to buy additional hardware. In this study, we explore the multi-modal physiological biometrics with end-to-end deep learning and feature-based traditional systems. We collected multi-modal physiological data of 80 people for five days using modern smartbands. We applied a deep learning approach to the multi-modal physiological data and used feature-based traditional machine learning classifiers. The CNN-LSTM model achieved a 9.31% equal error rate and outperformed other models in terms of authentication performance.Publication Metadata only Enhancement of throat microphone recordings by learning phone-dependent mappings of speech spectra(Institute of Electrical and Electronics Engineers (IEEE), 2013) N/A; Department of Computer Engineering; Turan, Mehmet Ali Tuğtekin; Erzin, Engin; PhD Student; Faculty Member; Department of Computer Engineering; Graduate School of Sciences and Engineering; College of Engineering; N/A; 34503We investigate spectral envelope mapping problem with joint analysis of throat- and acoustic-microphone recordings to enhance throatmicrophone speech. A new phone-dependent GMM-based spectral envelope mapping scheme, which performs the minimum mean square error (MMSE) estimation of the acoustic-microphone spectral envelope, has been proposed. Experimental evaluations are performed to compare the proposed mapping scheme to the state-of-theart GMM-based estimator using both objective and subjective evaluations. Objective evaluations are performed with the log-spectral distortion (LSD) and the wideband perceptual evaluation of speech quality (PESQ) metrics. Subjective evaluations are performed with the A/B pair comparison listening test. Both objective and subjective evaluations yield that the proposed phone-dependent mapping consistently improves performances over the state-of-the-art GMM estimator.Publication Metadata only End-to-end service-level management framework over multi-domain software defined networks(Institute of Electrical and Electronics Engineers (IEEE), 2016) N/A; N/A; N/A; Department of Electrical and Electronics Engineering; Bağcı, Kadir Tolga; Nacaklı, Selin; Şahin, Kemal Emrecan; Tekalp, Ahmet Murat; PhD Student; PhD Student; Master Student; Faculty Member; Department of Electrical and Electronics Engineering; Graduate School of Sciences and Engineering; Graduate School of Sciences and Engineering; Graduate School of Sciences and Engineering; College of Engineering; N/A; N/A; N/A; 26207We introduce a distributed, dynamic, end-to-end (E2E) service-level management framework over a multi-domain SDN in order to enable end users to negotiate with their service providers a level of service according to their needs and budget. In this framework, the service provider offers multiple levels of service and allocates network resources to each user to satisfy specific service level requests in a fair manner. To this effect, controllers of different domains negotiate with each other to satisfy the service level parameters of service requests, where functions that manage E2E services collaborate with functions that manage network resources of respective domains. The proposed framework and procedures have been verified over a newly developed large-scale multi-domain SDN emulation environment./ Öz: Çok-alanlı yazılım tanımlı ağlarda (YTA), son kul- lanıcıların servis sağlayıcıları ile belirli bir servis kalitesi için uzlaşmalarını sağlamak amacıyla da gıtık, dinamik ve uçtan uca servis kalitesi yönetimi önermekteyiz. Bu yapıda servis saglayıcıları birçok servis seviyesi önermekte ve ağ kaynaklarını kullanıcılara adil bir ¸sekilde bölü¸stürmektedir. Bu amaçla, uçtan uca servisleri ve her bir alanın kaynaklarını yöneten modüller işbirligi yaparak farklı alanların ağ yöneticilerinin servis istek- lerinin kısıtlarını sağlayacak şekilde birbirleri ile uzlaşmalarına olanak sağlamaktadır. Önerilen yapı ve modüller yeni geliştirilmiş büyük ölçekli çok-alanlı bir YTA’da test edilmiştir.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, Özgür Barış; 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 Fundamental frequency estimation for heterophonical Turkish music by using VMD(Institute of Electrical and Electronics Engineers (IEEE), 2016) Simsek, Berrak Ozturk; Akan, Aydin; Department of Computer Engineering; Bozkurt, Barış; Faculty Member; Department of Computer Engineering; College of Engineering; N/AIn this study, a new method is presented for the fundamental frequency estimation of heterophonical Turkish makam music recordings that include percusssive instrument by using Variational Mode Decomposition (VMD). VMD is a method to decompose an input signal into an ensemble of sub-signals (modes) which is entirely non-recursive and determines the relevant bands adaptively and estimates the corresponding modes concurrently. In order to decompose a given signal optimally, actuated by the narrow-band properties corresponding to the Intrinsic Mode Function definition used in Emprical Mode Decomposition (EMD), and we seek an ensemble of modes. Simulation results on fundamental frequency estimation of real music data show comparable performance to other common decomposition methods for music signals such as YIN and MELODIA based methods.Publication Metadata only Source and filter estimation for throat-microphone speech enhancement(IEEE-Inst Electrical Electronics Engineers Inc, 2016) N/A; Department of Computer Engineering; Turan, Mehmet Ali Tuğtekin; Erzin, Engin; PhD Student; Faculty Member; Department of Computer Engineering; Graduate School of Sciences and Engineering; College of Engineering; N/A; 34503In this paper, we propose a new statistical enhancement system for throat microphone recordings through source and filter separation. Throat microphones (TM) are skin-attached piezoelectric sensors that can capture speech sound signals in the form of tissue vibrations. Due to their limited bandwidth, TM recorded speech suffers from intelligibility and naturalness. In this paper, we investigate learning phone-dependent Gaussian mixture model (GMM)-based statistical mappings using parallel recordings of acoustic microphone (AM) and TM for enhancement of the spectral envelope and excitation signals of the TM speech. The proposed mappings address the phone-dependent variability of tissue conduction with TM recordings. While the spectral envelope mapping estimates the line spectral frequency (LSF) representation of AM from TM recordings, the excitation mapping is constructed based on the spectral energy difference (SED) of AM and TM excitation signals. The excitation enhancement is modeled as an estimation of the SED features from the TM signal. The proposed enhancement system is evaluated using both objective and subjective tests. Objective evaluations are performed with the log-spectral distortion (LSD), the wideband perceptual evaluation of speech quality (PESQ) and mean-squared error (MSE) metrics. Subjective evaluations are performed with an A/B comparison test. Experimental results indicate that the proposed phone-dependent mappings exhibit enhancements over phone-independent mappings. Furthermore enhancement of the TM excitation through statistical mappings of the SED features introduces significant objective and subjective performance improvements to the enhancement of TM recordings.Publication Metadata only Electric-field energy harvesting in wireless networks(Ieee-Inst Electrical Electronics Engineers Inc, 2017) Department of Electrical and Electronics Engineering; Department of Electrical and Electronics Engineering; Çetinkaya, Oktay; Akan, Özgür Barış; Other; Faculty Member; Department of Electrical and Electronics Engineering; College of Engineering; College of Engineering; N/A; 6647Electric-field energy harvesting (EFEH) can be considered as an emerging and promising alternative for self-sustainable next-generation WSNs. Unlike conventional harvesting methods that rely on ambient variables, EFEH provides more reliable and durable operation as it is operable with any voltage-applied conductive material. Therefore, it is better suited for advanced throughput and applications requiring a certain QoS. In this article, we introduce this newly emerging WSN paradigm, and focus on enabling EFEH technology for smart grid architectures, such as home, building, and near area networks, where the field intensity is relatively low. To this end, a practical methodology and a general use implementation framework have been developed for low-voltage applications by regarding compelling design issues and challenging source scarcity. The proposed double-layer harvester model is experimentally evaluated. Its performance in terms of implementation flexibility, sensor lifetime, and communication throughput is investigated. In addition, current challenges, open issues, and future research directions are discussed for the design of more enhanced EFEH wireless networks.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 Modeling and characterization of comb-actuated resonant microscanners(Iop Publishing Ltd, 2006) N/A; Department of Electrical and Electronics Engineering; Ataman, Çağlar; Ürey, Hakan; PhD Student; Faculty Member; Department of Electrical and Electronics Engineering; Graduate School of Sciences and Engineering; College of Engineering; N/A; 8579The dynamics of the out-of-plane comb-drive actuator used in a torsional resonant mode microscanner is discussed. The microscanner is fabricated using the standard SOI technology by Fraunhofer, IPMS and utilized in various display, barcode scanning, spectroscopy and other imaging applications. The device is a parametrically excited system and exhibits hysteretic frequency response, nonlinear transient response, subharmonic oscillations, multiple parametric resonances, and alternating-oscillation-frequency behavior. Analytical and numerical models are developed to predict the parametric system dynamics. The analytical model is based on the solution of the linear Mathieu equation and valid for small angular displacements. The numerical model is valid for both small and large deflection angles. The analytical and numerical models are validated with the experimental results under various ambient pressures and excitation schemes and successfully predict the dynamics of the parametric nature of the microscanner. As many as four parametric resonances are observed at 30 mTorr. The models developed in this paper can be used to optimize the structure and the actuator.