서해대교 건전성 모니터링을 위한 데이터 분석 및 건전성지수

김현수,김유희,박종칠,신수봉,Kim, Hyunsu,Kim, Yuhee,Park, Jongchil,Shin, Soobong 대한토목학회 2013 대한토목학회논문집 Vol.33 No.2

구조물의 건전성을 적절하게 모니터링을 하기 위해서는 정확하고 신뢰할 수 있는 계측데이터가 중요하다. 하지만, 실제로는 환경영향 및 센서고장으로 인해 불완전하고 신뢰할 수 없는 데이터가 계측된다. 센서고장인 경우에는 모니터링을 하기 위한 데이터 자체가 계측이 되지 않는 문제가 발생하고, 온도변화와 같은 환경영향에 의해서는 구조물이 손상되었을 때보다 고유진동수 등의 동특성이 더 큰 폭으로 변화한다. 본 논문에서는 구조건전성 모니터링을 위한 데이터 처리 및 분석의 체계적인 절차를 제시하였으며, 보정된 데이터를 사용하여 통계적으로 산정하는 건전성지수로 Mahalanobis 지수를 적용하였다. 제안된 방법을 트러스구조에서 수치적으로 모사한 데이터를 사용하여 검증하고, 서해대교에서 계측한 현장데이터에 적용하였다. It is important to collect reliable measured data for proper bridge health monitoring. However, in reality incomplete and unreliable data may be acquired due to sensor problems and environmental effects. In case of sensor malfunction, parts of measured data are missing and thus health monitoring cannot be carried out reliably. Due to environmental effects such as temperature variation, dynamic characteristics of natural frequencies may change as if the structure is damaged. The paper proposes a systematic procedure of data processing and data analysis for reliable structural health monitoring. Also, it applies the Mahalanobis distance as a health index computed statistically using revised data. The proposed procedure has been examined using numerically simulated data from a truss structure and then applied to a set of field data measured from Seohae cable-stayed bridge.

베이지안 알람 랭킹 시스템의 거짓 일반화 문제와 해결 방안

김현수(Hyunsu Kim),허기홍(Kihong Heo) 한국정보과학회 2021 한국정보과학회 학술발표논문집 Vol.2021 No.6

예비유아교사들의 자아존중감, 스트레스, 전공만족도 및 대학생활적응에 관한 연구

김현수(Kim, Hyunsu),유지은(Yoo, Jieun) 한국열린교육학회 2022 열린교육연구 Vol.30 No.2

본 연구는 예비유아교사들의 자아존중감, 스트레스, 전공만족도 및 대학생활적응의 관계를 탐색하였다. 이를 위해 267명의 예비유아교사들을 대상으로 설문자료를 수집하여 분석하였으며, 그 결과 첫째, 대학생활적응을 제외한 모든 변인들에서 학년에 따른 유의한 차이가 나타났다. 둘째, 상관관계 분석결과 자아존중감, 전공만족도, 대학생활적응은 서로 정적상관을 보였으며, 스트레스는 나머지 변인들과 부적상관을 보였다. 셋째, 위계적 회귀분석 결과, 대학생활적응에 영향을 미치는 영향력은 자아존중감, 전공만족도, 스트레스 순으로 나타났다. 본 연구 결과를 바탕으로 코로나19 시기 예비유아교사들의 대학생활적응을 지원할 수 있는 방안을 제안하였다. This study explored the relationships between self-esteem, stress, major satisfaction, and college adaptation of pre-service early childhood teachers. To this end, questionnaire data was collected and analyzed for 267 pre-service early childhood teachers, and as a result, first, significant differences according to grade were found in all variables except for college adaptation. Second, as a result of correlation analysis, self-esteem, major satisfaction, and college adaptation showed a positive correlation with each other, and stress showed a negative correlation with the remaining variables. Third, as a result of hierarchical regression analysis, the influence on college adaptation was in the order of self-esteem, major satisfaction, and stress. Based on the results of this study, suggestions and implications to support pre-service early childhood teachers college adaptation were discussed in the period of the COVID-19.

하이브리드 자동차 구동모터 비정상 소음 개선

김현수(Hyunsu Kim),김명규(Myunggyu Kim) 대한기계학회 2017 대한기계학회 춘추학술대회 Vol.2017 No.11

Electrical motor noise in hybrid electric vehicle (HEV) is in general expected that it has lower level in noise and vibration than conventional internal combustion engine does. In this paper, abnormal noise component, which may be annoying noise, of the traction motor occurred after an endurance vehicle test is investigated experimentally. The ±1 order of the number of slots is understood by a theoretical model, and the source of the abnormal noise is examined by cross-check investigation and is identified that it is caused by a failure of magnet fixing method. The improvement of the abnormal noise is confirmed by changing the fixing method from bond to mold.

아이 울음소리 음질 분석

김현수(Hyunsu Kim) 대한인간공학회 2019 大韓人間工學會誌 Vol.38 No.1

Objective: This study aims the sound quality analysis of baby crying sound to understand the sound characteristics of baby crying. Background: Baby crying may be the fundamental communication method between babies and adults. Thus, baby crying can represent various emotion, request, condition, or alarm. Due to those features, a number of studies are reported that medical diagnosis based on baby crying analysis are possible. Recently, unfortunate accident that baby is left in a car leading to sometimes death is often reported, so automatic detection of baby crying is also tried. However, there is few study showing the timefrequency analysis of baby crying which illustrates the intuitive understanding the characteristics of baby crying. Therefore, clear demonstration for the sound analysis for baby crying needs to be investigated. Method: 10 baby crying sounds are used for time-frequency analysis. For Fast Fourier Transform (FFT), Hann window is utilized, and 50% overlap is applied. Fundamental frequency of baby crying is found, and the magnitudes of harmonics are detected and tabled. Also, different crying patterns are compared with a typical crying sound with the same baby. Lastly, various sound sources, man and woman"s voice and an instrument, are investigated and compared. Results: Baby crying has certain characteristics which show the 1st fundamental component around below 500Hz, and 1~3kHz components tend to be amplified. In addition, different crying patterns show distinguishable sound characteristics. Conclusion: Baby crying is unique in terms of the sound characteristics which show human ears sensitivity. Application: The results can assist the study in the field of medical application for diagnosis of baby conditions or baby safety method detecting baby crying sound.

중국 상해 패션 시장의 특성과 한국 패션 브랜드의 경쟁력 분석

김현수 ( Hyunsue Kim ),이연희 ( Younhee Lee ),이지연 ( Jiyeon Lee ) 복식문화학회 2017 服飾文化硏究 Vol.25 No.2

This paper aims to analyze the characteristics of the contemporary Chinese fashion market and the competitiveness of Korean fashion brands in China. Fashion professionals experienced in both the Korean and Chinese fashion markets participated to investigate the Shanghai market and consumers. The results of in-depth interviews show that Shanghai is the most favorable city among Tier 1 cities for Korean fashion brands planning on entering into the Chinese market. Shanghai consumers are open to international brands and highly prefer newness in fashion. Contemporary menswear was selected as a potentially big market due to the increase of unique, young, upper-middle-class male consumers. The Korean fashion brands` strength is that they are capable of satisfying Shanghai consumers with excellent product planning and sensory design capabilities. Their disadvantage is that their brand recognition is weaker than that of global and international brands, and their ability to localize to the Chinese market is weak. The opportunity comes is from the Korean Wave, which is a positive for Korea`s products and has good geographical access. The threat is that the Shanghai market is fiercely competitive; having access to many worldwide brands, and the competitiveness of Chinese brands is on the rise. To enter the Shanghai market, creative design ability, trendy product development, skill, and appropriate PR methods such as using Korean culture contents would be required to satisfy the young, powerful consumers in Shanghai.

최대유사체계분석기법을 통한 클래식 음악공연시장 생태계 비교분석

김현수(Kim, Hyunsu),이동수(Lee, Dongsoo) 한국상품학회 2018 商品學硏究 Vol.36 No.2

This study aims to derive ecosystem of classical music performance market in Korea, USA and Germany using service value network model from an ecosystem perspective. Based on these results, we tried to propose the sustainable growth strategy of the market by comparing the classical music performance market of each country by applying the most similar systems design(MSSD). To do this, we conducted research on each step of deriving value actors, deriving ecosystem of each country and deriving differences-similarity on the basis of qualitative research techniques, and finally proposed a market development strategy for creating new services. The results show that the diversity of value actors and the linkage between value actors lead to diversification of products and services, which has a positive effect on market growth. Specific strategies include strengthening the linkage between the Tier 2 Enablers and the Tier 1 Enablers , linking and cooperating with various service providers, seeking diversification of service and revenue creation, form the relationship between consumers and each value actors. These findings are expected to contribute to the academic field, policy and practice. 본 연구는 클래식 음악공연시장을 생태계적 관점으로 바라보고 서비스 가치네트워크모델을 활용하여 한국, 미국, 독일의 클래식 음악공연시장의 생태계를 도출하고자 하였다. 또한 생태계 분석 결과를 기반으로 최대유사체계분석기법을 적용하여 각 국의 클래식 음악공연시장의 비교분석을 수행해 시장의 지속 성장전략을 제시하고자 하였다. 이를 위해 정성적 조사기법을 기반으로 가치행위주체 도출, 각 나라별 생태계 도출, 상이성-유사성 도출의 각 단계별로 연구를 진행하였으며 최종적으로 연구결과를 종합하여 새로운 서비스 창출을 위한 다양한 시장발전 전략을 제안하였다. 연구결과, 가치행위자의 다양성과 가치행위자 간의 연계성은 곧 제품 및 서비스의 다양화로 이어져 시장성장에 긍정적인 영향을 미친다는 점을 알 수 있었다. 구체적인 전략으로는 제2결합 지원자와 제1결합 지원자들의 연계강화, 다양한 서비스 지원주체와의 연계·협력, 서비스 제공자의 서비스 및 수익창출원의 다각화 모색, 소비자와 각 서비스 창출단계 별 행위자들과의 관계형성 등이 도출 되었다. 이러한 연구결과는 클래식 음악 분야에 학술적·정책적·실무적으로 기여할 것으로 기대된다.

IEEE 802.16.1a 기반 단말간 직접통신을 위한 전용채널 채널 추정

김현수(Hyunsu Kim),배지민(Jimin Bae),장성철(Sungcheol Chang),윤철식(Chulsik Yoon),최지훈(Jihoon Choi) 한국통신학회 2013 한국통신학회 학술대회논문집 Vol.2013 No.1

IEEE 802.16n 기반 단말간 직접통신을 위한 동기채널 설계

김현수(Hyunsu Kim),배지민(Jimin Bae),장성철(Sungcheol Chang),윤철식(Chulsik Yoon),최지훈(Jihoon Choi) 한국통신학회 2012 한국통신학회 학술대회논문집 Vol.2012 No.2

해양환경 내 미세플라스틱 생물막 연구현황 고찰

김현수(Hyunsu Kim),유근제(Keunje Yoo) 대한환경공학회 2021 대한환경공학회 학술발표논문집 Vol.2021 No.11