• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2008년도 춘계학술대회논문집
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• pp.212-217
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• 2008

Acoustic noises generated during motor operation in mechanical system are from electromagnetic, mechanical, aerodynamic, and electrical sources. For identification of mechanical noise origins, misalignment, unbalance, fan shape, resonance, and vibration modes have been extensively considered to describe noise behavior. An experiment-based approach as well as a mathematical approach needs to be adopted for a realistic study into noise and vibration of the motor, because motor noise characteristics differ from type to type due to various noise sources. In this paper, a brushless DC motor for air-conditioner fan is analyzed by finite element method to identify noise source, and the analysis results are verified by experiments, and sensitivity analysis is performed by design of experiments.

• 한국소음진동공학회논문집
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• 제19권9호
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• pp.863-869
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• 2009

Acoustic noises generated during motor operation in mechanical system are from electromagnetic, mechanical, aerodynamic and electrical sources. For identification of mechanical noise origins, misalignment, unbalance, fan shape, resonance, and vibration modes have been extensively considered to describe noise behavior. An experiment-based approach as well as a mathematical approach needs to be adopted for a realistic study into noise and vibration of the motor, because motor noise characteristics differ from type to type due to various noise sources. This paper analyzes noise characteristics of a brushless DC motor for air-conditioner fan, and proves that the test motor noise originates from acoustic modes of airspace in the motor. The motor noise sensitivity analysis by design of experiments reveals that the noise characteristics are closely related to switching frequency and frame thickness.

• Smart Structures and Systems
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• 제24권5호
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• pp.597-606
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• 2019

Damage detection based on dynamic characteristics of a structure is one of important roles in structural damage identification. It is difficult to detect local structural damage using traditional dynamic experimental methods due to a limited number of sensors used in an experiment. In this work, a non-contact test stand of fan blades is established, and a full-field noncontact test method, combined with three-dimensional digital image correlation, Bayesian operational modal analysis, and damage indices, is used to detect local damage of a fan blade under ambient excitation without use of baseline information before structural damage. The methodology is applied to detect invisible local damage on the fan blade. Such a method has a seemingly high potential as an alternative to detect local damage of blades with complex high-precision surfaces under extreme working conditions because it is a noncontact test method and can be used under ambient excitation without human participation.

• 한국콘텐츠학회논문지
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• 제19권5호
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• pp.296-305
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• 2019

한류의 성장과 더불어 팬덤 경제의 중요성이 제기됨에 따라 한류가 가지고 있는 경쟁력을 팬덤의 관점과 더불어 고려할 필요가 있다. 특히 팬덤 현상은 자신이 선호하는 스타를 동일시하고, 팬 커뮤티니에 관련 정보를 적극적으로 획득 및 공유하는 특성을 나타내고 있다. 이에 따라 본 연구에서는 중국, 일본, 베트남 소비자들 대상으로 한국의 국가 이미지가 한류 콘텐츠 이용의도에 미치는 영향관계를 파악하고, 팬덤 동일시의 매개효과를 검정하였다. 실증분석 결과 문화 이미지, 기업 이미지, 제품 이미지는 한류 콘텐츠 이용의도에 통계적으로 유의한 영향을 미치는 것으로 나타났다. 또한, 스타 동일시와 팬 커뮤니티 동일시는 문화 이미지가 한류 콘텐츠 이용의도에 미치는 영향 관계에서 부분매개를 하는 것으로 나타났다. 본 연구 결과는 한류를 국가 이미지 향상을 위한 후광효과 관점이, 아닌 한류의 지속적인 발전을 위한 선행요인임을 검정하고, 팬덤 현상의 매개효과를 실증적으로 검정하였다는 점에서 시사점을 갖는다.

• 한국콘텐츠학회논문지
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• 제21권6호
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• pp.480-493
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• 2021

본 연구는 디지털 미디어를 이용하는 팬덤이 사회적 참여를 수행하는 과정을 실증적으로 해명하는 데 목적이 있다. 이론적인 틀로 동일시 개념을 새롭게 해석하고 그루닉의 공중 상황 이론을 활용한다. 이를 위해 온라인이나 소셜 미디어를 활용하면서 방탄 소년단(BTS)의 가치를 실제 행동으로 실천하고 있는 팬덤, 아미를 대상으로 설문 조사를 실시하였다. 연구결과, 아미의 디지털 매개 커뮤니케이션 행위와 사회참여 사이의 긍정적인 관련성을 검증하였고, 아미가 방탄소년단에 대하여 경험하는 동일시가 매개 역할을 한다는 사실 역시 확인하였다. 특히, 개인이 팬 대상을 친구나 동료로 받아들이는 수평적 동일시는 팬 대상을 스타로 여기는 수직적 동일시보다 사회참여로 나아가는 데 더 큰 영향을 미쳤다. 본 연구는 디지털 미디어, 미디어 수용자, 팬덤 그리고 PR 등 다양한 연구 분야들의 성과들을 동원하여 개인의 미디어 이용과 사적 감정, 공적 행동 사이의 관련성을 밝혔다는 데 그 의미가 있다.

• 한국소음진동공학회논문집
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• 제13권6호
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• pp.460-466
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• 2003

The aeroacoustic characteristics and noise reduction method of a centrifugal fan for a bagless vacuum cleaner were studied. The major noise source of vacuum cleaner is the centrifugal fan. The impeller of the fan rotates over 30000 rpm and generates very high-level piercing noise. It was found that the dominant noise source of the fan is generated from the aerodynamic interaction between the highly rotating impeller and stationary diffuser. In order to reduce the high tonal sound generated from the aerodynamic interaction between the impeller and diffuser, tapered impeller was carefully designed and tested. The trailing edge of the tapered impeller was inclined and this reduces the flow interactions between the rotating impeller and the stationary diffuser because of some phase shift. The static efficiency of the new impeller is slightly lower than the conventional one. The overall SPL is reduced about 3.6 dBA. The SPL of blade passing frequency(BPF) is reduced about 6 dBA and the $2^{nd}$ BPF is reduced about 20 dBA. The vacuum cleaner with the tapered impeller has lower noise level than that of the previous impeller and the strong tonal sound was dramatically reduced.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 1998년도 춘계학술대회논문집; 용평리조트 타워콘도, 21-22 May 1998
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• pp.575-581
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• 1998

The noise sources in the outdoor unit of RAC(Room Air Conditioner) are identified by the sound intensity method. The main noise sources are compressor noise and fluid noise which is caused by the fan, heat exchanger and shroud. First, the fluid noise is reduced through the design ol new fan and shroud with high flow rate and low noise, reduction of the system resistance by rearrangement of heat exchanger, and optimization of the complex parameter between the fan and shroud. Next, in order to reduce the compressor noise, the new shape of compressor mount and sound-proof material was applied. As a result, the overall noise was reduced by 4-5dB(A).

• 한국추진공학회:학술대회논문집
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• 한국추진공학회 2003년도 제21회 추계학술대회 논문집
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• pp.271-277
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• 2003

최근 환경 소음이 사회적인 문제로 대두되고 있는 가운데, 생활수준의 향상으로 저소음화에 대한 요구가 증가되고 있는 실정이다. 이와 같이 소음에 관한 일반인들의 관심이 높아지면서 생환주변에서 주요 소음원으로 지적되고 있는 회전기계, 특히 가전제품을 비롯한 유동관련 기계류의 소음을 낮추기 위한 노력이 절실히 요구되고 있다. 본 소평팬에 대한 연구에서는 음압 및 음향인텐시티를 이용하여 소음원을 해석하였다. 이때, 광센서를 이용한 축류형 팬의 동기화가 수행되어졌고, 팬 형상에서 정확한 소음원의 위치를 규명하기 위한 기록시간의 결정이 제안되어졌다. 소음 발생하는 위치를 규명하였고, 지향성 연구를 통하여 축류형 팬의 방사형태를 결정하였으며, 음의 흐름도를 가시화 하였다.

• 연구윤리
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• 제1권2호
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• pp.11-13
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• 2020

Purpose: The author wants to specify scope of research, identify without giving burden, prevent unfair identification of the author, admit of production of the outcome, enact rules of identification, and build up foundation of development. Also, this study defines scope of publication of outcome of research to prevent unfair identification of authors and admit of them. Research design, data and methodology: The study described literary research, standard research, phenomenon research, and empirical result without methodologies, statistical analysis and scientific test and investigated operation system of KODISA cases. Results: At publication of findings of the research, researchers shall identify the ones of production of the finding to allocate help of the research. Conclusions: Scientific journals shall be controlled to develop ability and to grow up and have a system. Researchers shall give direction of other scientific journals. The study made efforts to be a model. KODISA Edition Team shall make an effort to keep and develop. So far, no regulation of identification of authors has produced disturbance so terminologies should be uniformed. Researchers shall keep rules of identification of authors to uniform and regulate identification of authors, conditions of authors, and order and correspondent authors. KODISA enacted rules of identification of authors for the first time in Korea to develop science.

• Nuclear Engineering and Technology
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• 제54권12호
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• pp.4684-4692
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• 2022

Radionuclide identification is an important part of the nuclear material identification system. The development of artificial intelligence and machine learning has made nuclide identification rapid and automatic. However, many methods directly use existing deep learning models to analyze the gamma-ray spectrum, which lacks interpretability for researchers. This study proposes an explainable radionuclide identification algorithm based on the convolutional neural network and class activation mapping. This method shows the area of interest of the neural network on the gamma-ray spectrum by generating a class activation map. We analyzed the class activation map of the gamma-ray spectrum of different types, different gross counts, and different signal-to-noise ratios. The results show that the convolutional neural network attempted to learn the relationship between the input gamma-ray spectrum and the nuclide type, and could identify the nuclide based on the photoelectric peak and Compton edge. Furthermore, the results explain why the neural network could identify gamma-ray spectra with low counts and low signal-to-noise ratios. Thus, the findings improve researchers' confidence in the ability of neural networks to identify nuclides and promote the application of artificial intelligence methods in the field of nuclide identification.