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Permanent URI for this collectionhttps://hdl.handle.net/20.500.14288/3
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Publication Metadata only An audio-driven dancing avatar(Springer, 2008) Balci, Koray; Kizoglu, Idil; Akarun, Lale; Canton-Ferrer, Cristian; Tilmanne, Joelle; Bozkurt, Elif; Erdem, A. Tanju; Department of Computer Engineering; N/A; N/A; Department of Computer Engineering; Department of Electrical and Electronics Engineering; Yemez, Yücel; Ofli, Ferda; Demir, Yasemin; Erzin, Engin; Tekalp, Ahmet Murat; Faculty Member; PhD Student; Master Student; Faculty Member; Faculty Member; Department of Computer Engineering; Department of Electrical and Electronics Engineering; College of Engineering; Graduate School of Sciences and Engineering; Graduate School of Sciences and Engineering; College of Engineering; College of Engineering; 107907; N/A; N/A; 34503; 26207We present a framework for training and synthesis of an audio-driven dancing avatar. The avatar is trained for a given musical genre using the multicamera video recordings of a dance performance. The video is analyzed to capture the time-varying posture of the dancer's body whereas the musical audio signal is processed to extract the beat information. We consider two different marker-based schemes for the motion capture problem. The first scheme uses 3D joint positions to represent the body motion whereas the second uses joint angles. Body movements of the dancer are characterized by a set of recurring semantic motion patterns, i.e., dance figures. Each dance figure is modeled in a supervised manner with a set of HMM (Hidden Markov Model) structures and the associated beat frequency. In the synthesis phase, an audio signal of unknown musical type is first classified, within a time interval, into one of the genres that have been learnt in the analysis phase, based on mel frequency cepstral coefficients (MFCC). The motion parameters of the corresponding dance figures are then synthesized via the trained HMM structures in synchrony with the audio signal based on the estimated tempo information. Finally, the generated motion parameters, either the joint angles or the 3D joint positions of the body, are animated along with the musical audio using two different animation tools that we have developed. Experimental results demonstrate the effectiveness of the proposed framework.Publication Metadata only Optical modulation with silicon microspheres(IEEE-Inst Electrical Electronics Engineers Inc, 2009) Gürlü, Oğuzhan; N/A; Department of Physics; Yüce, Emre; Serpengüzel, Ali; Master Student; Faculty Member; Department of Physics; Graduate School of Sciences and Engineering; College of Sciences; 245435; 27855In this letter, a silicon microsphere coupled to a silica optical fiber half coupler has been characterized for electrooptical modulation in the L-band at 1.55 mu m. Electrooptical modulation of the transmitted and the 90 degrees elastic scattered signals for both the TE and the TM polarizations of the microsphere resonances has been observed.Publication Metadata only Propagation of electromagnetic waves in linear media and pseudo-hermiticity(EPL Association, European Physical Society, 2008) Loran, F.; Department of Mathematics; Mostafazadeh, Ali; Faculty Member; Department of Mathematics; College of Sciences; 4231We express the electromagnetic field propagating in an arbitrary time-independent non-dispersive medium in terms of an operator that turns out to be pseudo-Hermitian for Hermitian dielectric and magnetic permeability tensors (epsilon) over left right arrow and (mu) over left right arrow. We exploit this property to determine the propagating field. In particular, we obtain an explicit expression for a planar field in an isotropic medium with (epsilon) over left right arrow = epsilon(1) over left right arrow and mu = mu(1) over left right arrow varying along the direction of the propagation. We also study the scattering of plane waves due to a localized inhomogeneity.Publication Metadata only Ordinal efficiency and dominated sets of assignments(Academic Press Inc Elsevier Science, 2003) Abdülkadiroğlu, Atila; Department of Economics; Sönmez, Tayfun; Faculty Member; Department of Economics; College of Administrative Sciences and Economics; N/AUsing lotteries is a common tool for allocating indivisible goods. Since obtaining preferences over lotteries is often difficult, real-life mechanisms usually rely on ordinal preferences over deterministic outcomes. Bogomolnaia and Moulin (J. Econom. Theory 19 (2002) 623) show that the outcome of an ex post efficient mechanism may be stochastically dominated They define a random assignment to be ordinally efficient if and only if it is not stochastically dominated. In this paper we investigate the relation between ex post efficiency and ordinal efficiency. We introduce a new notion of domination defined over sets of assignments and show that a lottery induces an ordinally efficient random assignment if and only if each subset of the full support of the lottery is undominated.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.Publication Metadata only Strain-controlled bulge test(Cambridge University Press (CUP), 2008) Akar, Orhan; Akın, Tayfun; Department of Mechanical Engineering; N/A; Alaca, Burhanettin Erdem; Toga, Kamil Buğra; Faculty Member; Master Student; Department of Mechanical Engineering; College of Engineering; Graduate School of Sciences and Engineering; 115108; N/AA closed-loop approach is adopted to implement strain rate Control during the bulge test. Due to the difficulty of measuring strains directly, the technique is based oil the conversion of displacement measurement to the corresponding strains using the plane-strain formulation. The necessary temporal evolution of the midpoint displacement of a rectangular diaphragm is derived under the condition of constant Strain rate and is Imposed as a control criterion. The technique is demonstrated oil 500-nm-thick Au diaphragms by applying, strain rates ranging from 2 x 10(-6) to 2 x 10(-4) s(-1). By measures the corresponding yield strength values, a Strain rate sensitivity of 0.11 is obtained, which is close to what was previously reported oil similar specimens using the microbending test.Publication Metadata only Lists as alternative discourse structures to narratives in preschool children's conversations(Taylor & Francis, 2004) N/A; Department of Psychology; Küntay, Aylin C.; Faculty Member; Department of Psychology; College of Social Sciences and Humanities; 178879This study examines a corpus of conversations of Turkish preschool-age children with adults, with the goal of analyzing 2 types of extended discourse structures (i.e., lists and narratives). Lists and narratives are compared with respect to (a) their internal structures, and (b) their social functions in the participants' daily interactions. The analyses suggest that although lists and narratives differ on structural grounds, they overlap in the functions they serve for the tellers. Lists constitute more of a descriptive structure, although temporality is foregrounded in narratives. Yet, both genres are used to express strips of past experience, and are employed by the same child in similar contexts, framed by similar metadiscourse comments, often blending into another. These findings suggest that, although lists and narratives are revealed as 2 clearly differentiable genres on formal analyses, lists carry some features of narrativity in children's conversational interactions.Publication Metadata only Transition to family practice in Turkey(Wiley, 2008) Yaman, Hakan; Department of Business Administration; Güneş, Evrim Didem; Faculty Member; Department of Business Administration; College of Administrative Sciences and Economics; 51391Introduction: Turkey's primary health care (PHC) system was established in the beginning of the 1960s and provides preventive and curative basic medical services to the population. This article describes the experience of the Turkish health system, as it tries to adapt to the European health system. It describes the current organization of primary health care and the family medicine model that is in the process of implementation and discusses implications of the transition for family physicians and the challenges faced in meeting the needs for health care staff. In Turkey a trend toward urbanization is evident and more staff positions in rural PHC centers are vacant. Shortages of physicians and an ineffective distribution of doctors are seen as a major problem. Family medicine gained popularity at the beginning of the 1990s, as a specialty with a 3-year postgraduate training program. Medical practitioners who are graduates of a 6-year medical training program and are already working in the PHC system are offered retraining courses. Better working conditions and higher salaries may be important incentives for medical practitioners to sign a contract with the social security institution of Turkey. Discussion: The lack of well-trained primary care staff is an ongoing challenge. Attempts to retrain medical practitioners to act as family physicians show promising results. Shortness of physician and health professionals and lack of time and resources in primary health care are problems to overcome during this process.Publication Metadata only Parametric characterizations of risk aversion and prudence(Springer, 2000) Nielsen, LT.; Department of Economics; Lajeri-Chaherli, Fatma; Faculty Member; Department of Economics; College of Administrative Sciences and Economics; N/AOur first main result says that whether one decision maker is more risk averse than another can be determined from their attitudes toward a given two-parameter family of risks. When all risks belong to this family, risk aversion can be compared even when initial wealth is random. Our second main result solves a long-standing problem in mean-variance analysis: what is the interpretation of the concavity of utility as a function of mean and variance? We show that in the case of normal distributions, this utility function is concave if and only if the agent has decreasing prudence.Publication Metadata only Broadly tunable continuous-wave orange-red source based on intracavity-doubled Cr4+: forsterite laser(Optical Soc Amer, 2002) Department of Physics; Sennaroğlu, Alphan; Faculty Member; Department of Physics; College of Sciences; 23851The operation of a room-temperature, continuous-wave, intracavity frequency-doubled Cr4+:forsterite laser capable of producing broadly tunable output in the orange-red region of the electromagnetic spectrum is described. Intracavity doubling was achieved in a periodically poled lithium niobate crystal that had gratings with different periods. Tunable second-harmonic output could be obtained between 613 and 655 am. At a wavelength of 630 nm, intracavity doubling yielded as much as 45 mW of continuous-wave output. To the author's knowledge, this represents the highest second-harmonic-power generation obtained to date with a continuous-wave Cr4+:forsterite laser.