• Proceedings of the Acoustical Society of Korea Conference
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• autumn
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• pp.389-392
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• 2001

To investigate the generation mechanism of the shock-associated noise, an underexpanded supersonic jet from an axisymmetic nozzle is simulated under the conditions of the Nozzle exit Mach number of 2 and the exit pressure ratio of Pe/Pe =1.5. The present simulation is performed based on the high-order accuracy and high-resolution ENO (Essentially Non-Oscillatory) scheme to capture the time-dependent flow structure representing the sound source. It was found that the shock-associated noise is generated by the weak interaction between the downstream propagating large turbulence structures of the jet flow and the quasi-periodic shock cell structure during the one is passing through the other. The directivity of propagating waves to the upstream is clearly shown in the visualization of pressure field. It is shown that the present calculation of the centerline pressure distribution is in fare agreement with the experimental data at the location of first shock cell.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.17 no.12
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• pp.1217-1222
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• 2007

With recent advance in automotive noise control engineering reducing major sound sources in the vehicle, customers perceive Buzz, Squeak and Rattle (BSR) as one of important indicators of vehicle quality and durability. As the long-term goal, we expect to establish the integrated design cycle for the reduction of the BSR noise in the early stage of vehicle development. which consist of design, prediction and evaluation procedures. This is possible only with great bulk of experimental data for BSR noise. In this paper, BSR noise is experimentally identified for vehicle doors, which have been traditionally considered as one of main sources of BSR noise. Based on this result, we proposed systematic method for the prevention of BSR noise in the vehicle doors.

• Proceedings of the Korean Society of Computer Information Conference
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• 2017.07a
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• pp.257-258
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• 2017

본 논문에서는 청각 장애인들은 시각에 의존하지 않고는 소리를 인지할 수 없다는 문제를 해결하기 위해 사운드를 시각화하는 웨어러블 시스템을 구현하였다. 시스템의 음성 인식 센서가 음성을 인식해 웨어러블 디스플레이에 전송된 메시지를 확인하고, 기상 재난 메시지를 웨어러블에서 실시간으로 확인하여 안전사고를 예방할 수 있게 하여 청각장애인의 어려움을 해결하였다.

• Proceedings of the Korea Information Processing Society Conference
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• 2018.10a
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• pp.656-659
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• 2018

통계적으로 일반인보다 청각장애인의 교통 사고율이 높은 것으로 나타나는데, 이는 청각 장애로 대표되는 차량을 포함한 위험 요소를 인식하기 힘든 상태나 조건에서 기인한다. 자동차가 접근하는 등의 소리를 듣지 못한다는 것은 결국 어떠한 위치에 위험요소가 존재하는지 인지하지 못함에 따라 사고로 이어질 가능성이 존재함을 의미하는데 이러한 문제점을 개선함과 동시에 대화중인 사람의 목소리를 시각화하여 정보를 제공함으로써 청각장애인으로 하여금 더 안전하고 쾌적한 삶을 누리게 하는 것이 청각장애인을 위한 사운드 정보 시각화 안경의 개발 목적이다. 위와 같은 배경을 통해 딥 러닝 기술에 기반하여 분류 과정을 거친 소리 정보의 판별을 통해 위험 요소를 인식한 후 시각화 하여 정보를 제공하는 디바이스를 제안한다.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.20 no.7
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• pp.644-650
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• 2010

Among various elements to affect customer's evaluation of vehicle quality, BSR(Buzz, Squeak, Rattle) are considered to be a mostly contributing factor. In this paper, we provide the test method which can be used to reduce the BSR noise of instrument panel in a vehicle. First, potential source regions of the instrument panel for BSR are localized by using the vibration-excitor and near-acoustic field visualization system. Then, subjective evaluation of BSR noise from the detected potential noise source regions is made with the Zwicker's loudness and time-varying loudness methods. This illustrative analysis reveals that current experimental methods can be used as a test procedure to systematically tackle BSR issues in early stage of the vehicle development cycle, which can result in the reduction of the production cost.

• Proceedings of the Korea Information Processing Society Conference
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• 2009.11a
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• pp.803-804
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• 2009

To accommodate constantly growing knowledge in scientific discourse that is revised over time by domain experts, we need to also evolve our ontology. The body of knowledge will get structured and refined as we develop a deeper understanding of issues. Keeping trail of new changes in semantically rich and formally sound mechanism has pragmatic advantages for providing the undo and redo facility and ontology recovery to a previous state. In this research, we have proposed a framework that support change logging and then using these logged changes for reverting ontology to a previous consistent state and visualization of change effects on ontology. The system is compared with ChangesTab of $Prot{\acute{e}}g{\acute{e}}$ and the results depict better accuracy for our system.

• The Journal of the Korea Contents Association
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• v.20 no.10
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• pp.89-99
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• 2020

In this study, we tried to produce moving-image works through sentiment analysis of music. First, Google natural language API was used for the sentiment analysis of lyrics, then the result was applied to the image visualization rules. In prior engineering researches, text-based sentiment analysis has been conducted to understand users' emotions and attitudes by analyzing users' comments and reviews in social media. In this study, the data was used as a material for the creation of artworks so that it could be used for aesthetic expressions. From the machine's point of view, emotions are substituted with numbers, so there is a limit to normalization and standardization. Therefore, we tried to overcome these limitations by linking the results of sentiment analysis of lyrics data with the rules of formative elements in visual arts. This study aims to transform existing traditional art works such as literature, music, painting, and dance to a new form of arts based on the viewpoint of the machine, while reflecting the current era in which artificial intelligence even attempts to create artworks that are advanced mental products of human beings. In addition, it is expected that it will be expanded to an educational platform that facilitates creative activities, psychological analysis, and communication for people with developmental disabilities who have difficulty expressing emotions.

• Journal of Korea Spatial Information System Society
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• v.9 no.3
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• pp.17-24
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• 2007

The noise problem is one of the major problems associated with large cities and is considered important factor not only in maintenance but also in development of cities. Accordingly, the noise map is being increasingly used in city planning and design. However, the existing two-dimensional noise maps only show regional, planar distribution of noise. This study presented a method to build a data model for analyzing and visualizing noise levels at fine scale considering the vertical distribution of noise in a building. By expanding the 2D topology concept used in conventional GIS to 3D, it suggested a 3D GIS data model that makes 3D spatial queries, analyses and visualization possible and applied the proposed approach to building a 3D noise information system. By building and testing the system, the study showed different functionalities including 3D spatial queries and 3D visualization of noise levels varying temporally or according as the height of sound-proof walls. In each case, the population exposed to noise was quantitatively computed to illustrate the potential in the areas of city planning and design.

• The Journal of the Acoustical Society of Korea
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• v.39 no.6
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• pp.576-584
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• 2020

In order to obtain basic information for using polyvinyl alcohol (PVA) gel as a tissue mimicking phantom for temperature visualization, the temperature change characteristics due to the focused ultrasound were examined for different concentration of PVA. To obtain the basic acoustic characteristics, the speed of sound, the attenuation coefficient, and the density depending on the PVA concentration were measured, and the thermodynamic characteristics, such as thermal conductivity and heat capacity, were measured. The range of temperature rising in the vicinity of the focal point due to the focused ultrasound was observed using a thermochromic film that changes color at 30 degree or more, and the discolored area was obtained by image processing of the recorded image. As the concentration of PVA increases in the given range of 2 wt% ~ 16 wt%, the area that rises above 30 degree inside the gel increases linearly. It is confirmed that the discolored area increases as the power applied to the focused ultrasonic transducer increases. These results showed good agreement with the simulation results using the finite element method.

• Journal of The Korean Association For Science Education
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• v.21 no.3
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• pp.497-505
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• 2001

In this study, the relationships among students' conceptual understanding of molecular structure and cognitive variables were investigated for 165 high school students. After they had learned 'High School Chemistry II' for two semesters, the tests of conception concerning molecular structure, spatial visualization ability, logical thinking ability, mental capacity, and learning approach were administered. The results indicated that students' conceptual understanding of molecular structure was not sound, and several misconceptions were found. The scores of the conception test were significantly correlated with all the cognitive variables studied. Multiple regression analyses were conducted to examine the predictive influences of students' cognitive variables on their conceptual understanding. Meaningful learning approach was the most significant predictor and were followed by logical thinking ability, rote learning approach, and mental capacity. However, spatial visualization ability did not have the predictive power.