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Permanent URI for this collectionhttps://hdl.handle.net/20.500.14288/6
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Publication Open Access User interface paradigms for visually authoring mid-air gestures: a survey and a provocation(CEUR-WS, 2014) Department of Media and Visual Arts; Department of Computer Engineering; Baytaş, Mehmet Aydın; Yemez, Yücel; Özcan, Oğuzhan; Faculty Member; Faculty Member; Department of Media and Visual Arts; Department of Computer Engineering; College of Social Sciences and Humanities; College of Engineering; N/A; N/A; 12532Gesture authoring tools enable the rapid and experiential prototyping of gesture-based interfaces. We survey visual authoring tools for mid-air gestures and identify three paradigms used for representing and manipulating gesture information: graphs, visual markup languages and timelines. We examine the strengths and limitations of these approaches and we propose a novel paradigm to authoring location-based mid-air gestures based on space discretization.Publication Open Access Engagement rewarded actor-critic with conservative Q-learning for speech-driven laughter backchannel generation(Association for Computing Machinery (ACM), 2021) Department of Computer Engineering; Bayramoğlu, Öykü Zeynep; Erzin, Engin; Sezgin, Tevfik Metin; Yemez, Yücel; Faculty Member; Faculty Member; Faculty Member; Department of Computer Engineering; Koç Üniversitesi İş Bankası Yapay Zeka Uygulama ve Araştırma Merkezi (KUIS AI)/ Koç University İş Bank Artificial Intelligence Center (KUIS AI); College of Engineering; Graduate School of Sciences and Engineering; N/A; 34503; 18632; 107907We propose a speech-driven laughter backchannel generation model to reward engagement during human-agent interaction. We formulate the problem as a Markov decision process where speech signal represents the state and the objective is to maximize human engagement. Since online training is often impractical in the case of human-agent interaction, we utilize the existing human-to-human dyadic interaction datasets to train our agent for the backchannel generation task. We address the problem using an actor-critic method based on conservative Q-learning (CQL), that mitigates the distributional shift problem by suppressing Q-value over-estimation during training. The proposed CQL based approach is evaluated objectively on the IEMOCAP dataset for laughter generation task. When compared to the existing off-policy Q-learning methods, we observe an improved compliance with the dataset in terms of laugh generation rate. Furthermore, we show the effectiveness of the learned policy by estimating the expected engagement using off-policy policy evaluation techniques.Publication Open Access An information theoretical analysis of broadcast networks and channel routing for FRET-based nanoscale communications(Institute of Electrical and Electronics Engineers (IEEE), 2012) Kuşcu, Murat; Malak, Derya; Akan, Özgür Barış; Faculty Member; College of EngineeringNanoscale communication based on Forster Resonance Energy Transfer (FRET) enables nanomachines to communicate with each other using the excited state of the fluorescent molecules as the information conveyer. In this study, FRET-based nanoscale communication is further extended to realize FRET-based nanoscale broadcast communication with one transmitter and many receiver nanomachines, and the performance of the broadcast channel is analyzed information theoretically. Furthermore, an electrically controllable routing mechanism is proposed exploiting the Quantum Confined Stark Effect (QCSE) observed in quantum dots. It is shown that by appropriately selecting the employed molecules on the communicating nanomachines, it is possible to control the route of the information flow by externally applying electric field in FRET-based nanonetworks.Publication Open Access Ultraslow optical modes in Bose-Einstein condensates(Society of Photo-optical Instrumentation Engineers (SPIE), 2007) Tarhan, Devrim; Postacıoğlu, Nazmi; Department of Physics; Müstecaplıoğlu, Özgür Esat; Faculty Member; Department of Physics; College of Sciences; 1674Light can be slowed down to ultraslow speeds via electromagnetically induced transparency in atomic Bose-Einstein condensates. This is thought to be useful for storage of quantum information for weak probe pulses. We investigate the effects of inhomogeneous density profile of-the condensate on propagation of such ultraslow pulses. We find that spatial density of an atomic condensate leads to a graded refractive index profile, for an off-resonant probe pulse when condensate parameters are suitably chosen. Within the window of negligible absorption, conditions for degenerate multiple waveguide modes are determined. Both analytical and numerical studies are presented to reveal the effects of experimentally controllable parameters, such as temperature and interatomic interaction strength on the number of modes. Group velocity dispersion and modal dispersion are discussed. The effect of waveguide dispersion, in addition to usual material dispersion, on ultraslow pulses is pointed out.Publication Open Access On the capacity of diffusion-based molecular communications with SiNW FET-based receiver(Institute of Electrical and Electronics Engineers (IEEE), 2016) Department of Electrical and Electronics Engineering; Kuşcu, Murat; Akan, Özgür Barış; Faculty Member; Department of Electrical and Electronics Engineering; College of EngineeringMolecular communication (MC) is a bio-inspired communication method based on the exchange of molecules for information transfer among nanoscale devices. Although MC has been extensively studied from various aspects, limitations imposed by the physical design of transceiving units have been largely neglected in the literature. Recently, we have proposed a nanobioelectronic MC receiver architecture based on the nanoscale field effect transistor-based biosensor (bioFET) technology, providing noninvasive and sensitive molecular detection at nanoscale while producing electrical signals at the output. In this paper, we derive analytical closed-form expressions for the capacity and capacity-achieving input distribution for a memoryless MC channel with a silicon nanowire (SiNW) FET-based MC receiver. The resulting expressions could be used to optimize the information flow in MC systems equipped with nanobioelectronic receivers.Publication Open Access Observation of two-photon interference using the zero-phonon-line emission of a single molecule(Institute of Physics (IOP) Publishing, 2006) Ehrl, M.; Hellerer, Th.; Brauchle, C.; Zumbusch, A.; Department of Physics; Müstecaplıoğlu, Özgür Esat; Kiraz, Alper; Faculty Member; Faculty Member; Department of Physics; College of Sciences; 1674; 22542We report the results of coincidence counting experiments at the output of a Michelson interferometer using the zero-phonon-line emission of a single molecule at 1.4 K. Under continuous wave excitation, we observe the absence of coincidence counts as an indication of two-photon interference. This corresponds to the observation of Hong-Ou-Mandel correlations.Publication Open Access SimMBM channel simulator for media-based modulation systems(Institute of Electrical and Electronics Engineers (IEEE), 2021) Yiğit Zehra; Altunbaş, İbrahim; Department of Chemical and Biological Engineering; Başar, Ertuğrul; Faculty Member; Department of Chemical and Biological Engineering; College of Engineering; 149116Media-based modulation (MBM), exploiting rich scattering properties of transmission environments via different radiation patterns of a single reconfigurable antenna (RA), has brought new insights into future communication systems. In this study, considering this innovative transmission principle, we introduce the realistic, two-dimensional (2D), and open-source SimMBM channel simulator to support various applications of MBM systems at sub-6 GHz frequency band in different environments.Publication Open Access Quantum state transfer among crystallographic groups of N-V centers in diamond(Society of Photo-optical Instrumentation Engineers (SPIE), 2011) Department of Physics; Müstecaplıoğlu, Özgür Esat; Faculty Member; Department of Physics; College of Sciences; 1674We investigate collections of Nitrogen-Vacancy (N-V) Centers in diamond crystals coupled to a circuit QED system of a coplanar waveguide (CPWG) resonator. Our analysis reveals that different symmetry axes oriented N-V centers in the diamond host can be grouped into bosonic modes of collective quasi-spin wave excitations so that the hybrid system can be described as an analog of an exciton-polariton type cavity QED model. We examine such model for quantum state transfer among distinct crystallographic groups of N-V centers in a single diamond as well as two spatially distant diamonds. Rabi oscillations, mode entanglement, possible use of N-V classes as spin ensemble qubits and an implementation of continuous-time quantum random walk are discussed.Publication Open Access Craft: a benchmark for causal reasoning about forces and in teractions(Association for Computational Linguistics (ACL), 2022) Ateş, Tayfun; Ateşoğlu, M. Şamil; Yiğit, Çağatay; Department of Computer Engineering; Department of Psychology; Erdem, Aykut; Göksun, Tilbe; Yüret, Deniz; Kesen, İlker; Kobaş, Mert; Faculty Member; Faculty Member; Faculty Member; Master Student; Department of Computer Engineering; Department of Psychology; Koç Üniversitesi İş Bankası Yapay Zeka Uygulama ve Araştırma Merkezi (KUIS AI)/ Koç University İş Bank Artificial Intelligence Center (KUIS AI); Graduate School of Sciences and Engineering; College of Engineering; College of Social Sciences and Humanities; 20331; 47278; 179996; N/A; N/A; N/AHumans are able to perceive, understand and reason about causal events. Developing models with similar physical and causal understanding capabilities is a long-standing goal of artificial intelligence. As a step towards this direction, we introduce CRAFT1, a new video question answering dataset that requires causal reasoning about physical forces and object interactions. It contains 58K video and question pairs that are generated from 10K videos from 20 different virtual environments, containing various objects in motion that interact with each other and the scene. Two question categories in CRAFT include previously studied descriptive and counterfactual questions. Additionally, inspired by the Force Dynamics Theory in cognitive linguistics, we introduce a new causal question category that involves understanding the causal interactions between objects through notions like cause, enable, and prevent. Our results show that even though the questions in CRAFT are easy for humans, the tested baseline models, including existing state-of-the-art methods, do not yet deal with the challenges posed in our benchmark.Publication Open Access TFOS European Ambassador meeting: unmet needs and future scientific and clinical solutions for ocular surface diseases(Elsevier, 2020) Erickson, Susan; Sullivan, Ammy Gallant; Barabino, Stefano; Begovic, Enesa; Benitez-del-Castillo Jose M.; Bonini Stefano; Borges Jose Salgado; Brzheskiy, Vlademir; Bulat, Nina; Cerim, Alma; Craig, Jennifer P.; Cușnir, Valeriu Jr.; Cusnir, Valeriu; Cusnir, Vitalie; Doan Serge; Dülger, Erol; Farrant, Sarah; Geerling, Gerd; Goldblum, David; Golubev, Sergey; Gomes, Jose A.P.; González-Méijome, Jose Manuel; Grupcheva, Christina N.; Gündüz, Ömür Uçakhan; Horwath-Winter, Jutta; Källmark, Fredrik; Karanadze, Nino; Karcic, Huda Hajjir; Karcic, Suvad; Kontadakis, Georgious; Messmer, Elisabeth M.; Mrugacz, Malgorzata; Murphy, Conor; O'Leary, Olivia E.; Procopciuc, Vitalie; Pult, Heiko; Raus, Peter; Setälä, Niko; Stanila, Adrina; Stanila, Den Mircea; Utheim, Toor Paeske; Vehof, Jelle; Versura, Piera; Villani, Edoardo; Willcox, Mark D. P.; Wolffsohn, James S.; Zagórski, Zebigniew; Zoega, Gunnar Mar; Sullivan, David A.; Şahin, Afsun; Faculty Member; School of Medicine; 171267The mission of the Tear Film & Ocular Surface Society (TFOS) is to advance the research, literacy, and educational aspects of the scientific field of the tear film and ocular surface. Fundamental to fulfilling this mission is the TFOS Global Ambassador program. TFOS Ambassadors are dynamic and proactive experts, who help promote TFOS initiatives, such as presenting the conclusions and recommendations of the recent TFOS DEWS II™, throughout the world. They also identify unmet needs, and propose future clinical and scientific solutions, for management of ocular surface diseases in their countries. This meeting report addresses such needs and solutions for 25 European countries, as detailed in the TFOS European Ambassador meeting in Rome, Italy, in September 2019.