• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2013.04a
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• pp.379-380
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• 2013

• English Language & Literature Teaching
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• v.13 no.2
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• pp.129-153
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• 2007

When English language teachers are deciding on their priorities for teaching pronunciation, it is imperative to know what kind of differences and errors are most likely to interfere with communication, and what special problems particular first-language speakers will have with English pronunciation. In other words, phoneme discrimination skill is an integral part of speech processing for the EFL learners' learning to converse in English. Training using sound visualization technique can be effective in improving second language learners' perceptions and productions of segmental and suprasegmental speech contrasts. This study assessed the efficacy of a pronunciation training that provided visual feedback for EFL learners acquiring pitch and durational contrasts to produce and perceive English phonemic distinctions. The subjects' ability to produce and to perceive novel English words was tested in two contexts before and after training; words in isolation and words in sentences. In comparison with an untrained control group, trainees showed improved perceptual and productive performance, transferred their knowledge to new contexts, and maintained their improvement three months after training. These findings support the feasibility of learner-centered programs using sound visualization technique for English language pronunciation instruction.

• 한국HCI학회:학술대회논문집
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• 2007.02a
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• pp.447-454
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• 2007

본 논문에서는 사용자의 가상환경 내의 위치 정보에 대한 감각을 향상시키는 방법론으로서 햅틱 피드백(haptic feedback)과 사운드 피드백(sound feedback)의 모달리티를 활용한 그리드(grid)를 제안한다. 제안된 그리드는 사용자의 3차원 공간 내의 움직임(explorative procedure)에 추가적인 비 시각적인(non-visual) 위치정보 피드백을 부여하는데 그 목적을 두고 있다. 햅틱 모달리티를 활용한 3차원 그리드는 SensAble사의 PHANTOM(R) Omni$^{TM}$ 를 활용하여 설계되었으며, 사운드 모달리티를 활용한 경우 저주파 배경음의 주파수 특성(frequency characteristics of sound source)을 사용자 손의 공간 좌표값에 근거하여 재생 시의 표본 추출 비율(sampling rate)를 연속적으로 바꾸는 방식으로 설계되었다. 이러한 공간 그리드는 두 모달리티 각각의 독립적인 제시 및 동시 제시/제거를 통해 평가되었으며, 동시 제시의 경우 두 모달리티간의 어긋남(cross-modal asynchrony)이 없도록 설계되어 사용자의 공간 작업 시 모달리티간의 조화 (manipulating congruency)를 확보할 수 있도록 하였다. 실험을 통해 얻어진 결과는 그것의 통계적 유의미성을 분석하기 위해 다원변량분석과 사후검증(Turkey. HSD)을 거쳐 해석이 되었다. 공간 내 특정 좌표 선택을 기준으로 하는 그리드의 사용자 평과 결과, 3차원 내의 움직임에 대해 햅틱 및 사운드 피드백의 비 시각적 피드백은 사용자의 공간 작업의 오차를 줄여 주고 있음이 확인되었다. 특히 시각적인 정보만으로 확인하기 어려운 Z축 상의 움직임은 그리드의 도움으로 그 오차정도가 50% 이상 줄어 드는 것으로 확인되었다(F=19.82, p<0.01). 이러한 시각적 정보를 보존하는 햅틱, 사운드 피드백 방식을 HCI의 중요한 요소인 사용성과 유용성과 연관시켜 MMHCI(multimodal human-computer interaction) 방법론으로의 적용 가능성을 검토해 본다.

• Proceedings of the ESK Conference
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• 1995.10a
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• pp.3-12
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• 1995

In this research, we investigated the effect of three visual feedback conditions (direct viewing, one-monitor viewing, and tow-monitors viewing) on the task performance of human operator in teloperation task. The three different level of task difficulties under each concitions were performed by thirty-six subjects. The result of the experiments was analysed by the task difficulties, and the measurements of performance are the task completion time and the frequency of task errors. In a teleoperator, the participation of a human operator is always required, and the man-machine interface and the operator's abilities is an important issue. Recently, the different types of sensory feedback conditions(force, vision, sound, tactile, etc) for teleoperation is a very active research area in ergonomics. Among them, visual feedback conditon is an important sense that can provide the information of task environment. Therefore, the sufficient understandings and investigation for human ability under various visual feedback conditions is required to establish the efficient man-machine interface of teleoperation. The result showed that the visual feecback conditions and the level of task difficulties have a significant effect on the task performance. For three level of task difficulties, the task completion time was the shortest under the condition of direct viewing. The number of task errors under the conditions of direct viewing and two-monitors viewing were reduced by more than half compare to that of one-monitor viewing.

• Journal of the Society of Disaster Information
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• v.12 no.3
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• pp.235-241
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• 2016

Recently our country was entering a high-tech society with social and economic development. However, the individual's ability to respond to disasters is lowered by the increase in complexity society. Accurate situation assessment and disaster response by a margin of personal information that can identify when a disaster has been difficult. Until now, by leveraging Standard speaker was the emergency alert broadcast. However, it was difficult to have regular speakers reverberation, a distinct attenuation of sound by listening to the sound, etc. due to the reflection of sound. By using a directional speaker that is characteristic of the sound attenuation of sound is straight to solve this problem and obtain feedback on measures that can effectively provide the oocytes to a valid information on a disaster situation and the evacuation.

• Journal of the Korean Institute of Telematics and Electronics
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• v.20 no.6
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• pp.58-61
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• 1983

This is a Loudness Control Circuit in an audio amplifier controlled by feedback type volume control variable resistors. This circuit consists of Bridged Twin T network and a ordinary variable resistor. The variably resistor acts not only as a volume control by varying feedback qupntity, but also as Loudness Control through the characteristics variation by Sound Level. This new Loudness Control Circuit showed ideal compensation characteristics that agree computer simulation and measured datas.

• Journal of the Ergonomics Society of Korea
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• v.19 no.3
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• pp.51-60
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• 2000

Non-verbal sound feedback, called earcon, has been used for portable digital electronic products to give appropriate information for the selected function. This study evaluated usability based on user cognition time, error rate, and subjective satisfaction using 20 male and female subjects. The study compared five major user functions from a portable digital electronic product with currently available earcons and the same functions from the product with the new earcons (suggested by this study) which considered user cognitive characteristics, such as loudness, pitch, melody, and length. For subjective evaluation, the study assessed various earcons by subjective impression of sounds using the seven-point rating scales. Major statistical results indicated that the new earcons significantly reduced user error rates and generally improved user performance functions, such as 'play, off, stop, fast forward, and rewind.'

• 한국전산유체공학회:학술대회논문집
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• 2010.05a
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• pp.2-4
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• 2010

Due to rapid progress in the performance of high-end computers, numerical prediction of fluid flow and flow-induced sound is expected to become a vital tool for aero- and hydro- dynamic design of various flow-related products. This presentation focuses on the applications of large-scale numerical simulations to complex engineering problems with a particular emphasis placed on the low-speed flows. Flow field computations are based on a large eddy simulation that directly computes all active eddies in the flow and models only those eddies responsible for energy dissipations. The sound generated from low-speed turbulent flows are computed either by direct numerical simulation or by decoupled methods, according to whether or not the feedback effects of the generated sound onto the source flow field can be neglected. Several numerical examples are presented in order to elucidate the present status of such computational methods and discussion on the future prospects will also be given.

• 한국전산유체공학회:학술대회논문집
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• 2004.03a
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• pp.113-118
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• 2004

This paper presents a two-dimensional edge tone to predict the frequency characteristics of the discrete oscillations of a jet-edge feedback cycle by the finite difference lattice Boltzmann method (FDLBM). We use a new lattice BGK compressible fluid model that has an additional term and allow larger time increment comparing the conventional FDLBM, and also use a boundary fitted coordinates. The jet is chosen long enough in order to guarantee the parabolic velocity profile of the jet at the outlet, and the edge consists of a wedge with an angle of $\alpha=23^0$. At a stand-off distance $\omega$, the edge is inserted along the centreline of the jet, and a sinuous instability wave with real frequency f is assumed to be created in the vicinity of the nozzle and th propagate towards the downstream. We have succeeded in capturing very small pressure fluctuations result from periodically oscillation of jet around the edge. That pressure fluctuations propagate with the sound speed. Its interaction with the wedge produces an irrotational feedback field which, near the nozzle exit, is a periodic transverse flow producing the singularities at the nozzle lips. The lattice BGK model for compressible fluids is shown to be one of powerful tool for computing sound generation and propagation for a wide range of flows.

• Journal of Ship and Ocean Technology
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• v.12 no.1
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• pp.1-15
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• 2008

An edgetone is the discrete tone or narrow-band sound produced by an oscillating free shear layer, impinging on a rigid surface. In this paper, 2-dimensional edgetone to predict the frequency characteristics of the discrete oscillations of a jet-edge feedback cycle is presented using lattice Boltmznan model with 21 bits, which is introduced a flexible specific heat ratio y to simulate diatomic gases like air. The blown jet is given a parabolic inflow profile for the velocity, and the edges consist of wedges with angle 20 degree (for symmetric wedge) and 23 degree (for inclined wedge), respectively. At a stand-off distance w, the edge is inserted along the centerline of the jet, and a sinuous instability wave with real frequency is assumed to be created in the vicinity of the nozzle exit and to propagate towards the downward. Present results presented have shown in capturing small pressure fluctuating resulting from periodic oscillation of the jet around the edge. The pressure fluctuations propagate with the speed of sound. Their interaction with the wedge produces an irrotational feedback field which, near the nozzle exit, is a periodic transverse flow producing the singularities at the nozzle lips. It is found that, as the numerical example, satisfactory simulation results on the edgetone can be obtained for the complex flow-edge interaction mechanism, demonstrating the capability of the lattice Boltzmann model with flexible specific heat ratio to predict flow-induced noises in the ventilating systems of ship.