충격햄머 실험에 의한 1자유도 주파수응답함수의 오차와 해결방법

안세진,정의봉 한국소음진동공학회 2002 한국소음진동공학회 논문집 Vol.12 No.9

The spectrum of impulse response signal from an impulse hammer testing is widely used to obtain frequency response function(FRF). However the FRFs obtained from impact hammer testing have not only leakage errors but also finite record length errors when the record length for the signal processing is not sufficiently long. The errors cannot be removed with the conventional signal analyzer which treats the signals as if they are always steady and periodic. Since the response signals generated by the impact hammer are transient and have damping, they are undoubtedly non-periodic. It is inevitable that the signals be acquired for limited recording time, which causes the errors. This paper makes clear the relation between the errors of FRF and the length of recording time. A new method is suggested to reduce the errors of FRF in this paper. Several numerical examples for 1-dof model are carried out to show the property of the errors and the validity of the proposed method.

Shape-controlled Electrodeposition of Standing Pt Nanoplates on Gold Substrates as a Sensor Platform for Nitrite Ions

안세진,SHANMUGAMMANIVANNAN,서예지,김규원 대한화학회 2019 Bulletin of the Korean Chemical Society Vol.40 No.6

Electrochemically deposited standing platinum (Pt) nanoplates were fabricated on gold (Au) substrate assisted by the amine functionalized silane and L-glutamic acid (LG) as nucleating and structure directing agents, respectively. Various win over factors responsible for the electrodeposition of the Pt nanoplates was methodologically analyzed. The treatment time with the thiol functionalized silane (M) and the role of LG were found to be decisive for the demonstration of Pt nanoplates display at the Au substrate. Plausible growth mechanism was proposed for the vertical growth and random orientation of the Pt nanoplates. Constructed Pt nanoplates displayed substrate were applied as a sensor platform toward the nitrite ion detection; improved performance was noted than that of the controlled experiments. Furthermore, sensor platform had exhibited recent selectivity toward the nitrite ions from the mixture of possible interferences.

최적화 기법을 이용한 다자유도 충격응답스펙트럼의 오차 개선

안세진,정의봉 한국소음진동공학회 2002 한국소음진동공학회 논문집 Vol.12 No.10

The spectrum of impulse response signal from an impulse hammer testing is widely used to obtain frequency response function (FRF) of the structure. However the FRFs obtained from impact hammer testing have not only leakage errors but also finite record length errors when the record length for the signal processing is not sufficiently long. The errors cannot be removed with the conventional signal analyzer which treats the signals as if they are always steady and periodic. Since the response signals generated by the impact hammer are transient and have damping, they are undoubtedly non-periodic. It is inevitable that the signals be acquired for limited recording time, which causes the finite record length error and the leakage error. In this paper, the errors in the frequency response function of multi degree of freedom system are formulated theoretically. And the method to remove these errors is also suggested. This method is based on the optimization technique. A numerical example of 3-dof model shows the validity of the proposed method.

쇼크타입 수직방향 전신진동에 대한 생체동역학적 반응의 비선형성

안세진,유완석,정의봉 대한기계학회 2007 大韓機械學會論文集A Vol.31 No.2

Poster Session : 중성 염화물 분위기에서 MnS 가 304 스테인리스강의 공식개시에 미치는 영향

안세진,권혁상 한국부식방식학회(구 한국부식학회) 2002 춘계 학술발표회 초록집 Vol.- No.-

Effect of Masking Dental Region on Determining Osteoporosis of Artificial Intelligence on Panoramic Radiographs

안세진,송인자,이재서,이경민,윤숙자,송호준 대한구강악안면병리학회 2023 대한구강악안면병리학회지 Vol.47 No.6

This study aimed to investigate which areas AI is sensitive when inputting panoramic radiographs with dental area masked and when inputting unmasked ones. Therefore, the null hypothesis of this study was that masking dental area would not make a difference in the sensitive areas of osteoporosis determination of AI. For this study 1165 female(average age 48.4 ± 23.9 years) from whom panoramic radiographs were taken were selected. Either osteoporosis or normal should be clearly defined by oral and maxillofacial radiologists. The panoramic radiographs from the female were classified as either osteoporosis or normal according to the mandibular inferior cortex shape. VGG-16 model was used to get training, validating, and testing to determine between osteoporosis or normal. Two experiments were performed; one using unmasked images of panoramic radiographs, and the other using panoramic radiographs with dental region masked. In two experiments, accuracy of VGG-16 was 97.9% with unmasked images and 98.6% with dental-region-masked images. In the osteoporosis group, the sensitive areas identified with unmasked images included cervical vertebrae, maxillary and mandibular cancellous bone, dental area, zygomatic bone, mandibular inferior cortex, and cranial base. The osteoporosis group shows sensitivity on mandibular cancellous bone, cervical vertebrae, and mandibular inferior cortex with masked images. In the normal group, when unmasked images were input, only dental region was sensitive, while with masked images, only mandibular cancellous bone was sensitive. It is suggestive that when dental influence of panoramic radiographs was excluded, AI determined osteoporosis on the mandibular cancellous bone more sensitively.

토픽 모델링을 활용한 기후기술 감축 R&D 사업의 특허 개발 내용 분석

안세진,김강배,이종석,염성찬 한국지식재산연구원 2020 지식재산연구 Vol.15 No.3

Since the Paris Agreement went into effect, countries around the world have been making great efforts to develop technologies to reduce greenhouse gas emissions and transfer climate technology to developing countries. Korea is also expanding R&D investment in the climate technology sector to cope with climate change. As the importance of national R&D projects for climate technology has increased, social demands for the policy responsibility of R&D projects are also increasing. In line with this perception, the government is conducting performance evaluations of national R&D projects, but the problem is that they are focusing on measuring and evaluating the visible aspects of individual projects. There has also been a constant criticism that the emphasis on performance evaluation and raising the question of the need to consider the efficiency, quality, and value of the R&D project. This study identified whether the research goals of national climate technology R&D were actually achieved through content analysis of patent results. Based on this, it presented policy implications for future climate technology R&D projects. In particular, the government intended to overcome the limitations of existing research biased toward quantitative research by using text mining techniques as a research method. 세계 각국은 온실가스 배출 감축을 위한 기술개발과 정부재원 투자확대를위해 노력하고 있다. 기후변화 대응의 중요성을 인식하고 우리나라에서도기후변화 대응을 위한 연구개발 사업을 확대하여 미래시장 경쟁력 확보를기대하고 있다. 기후변화 대응 측면에서 국가연구개발사업의 중요성과 기대가 증가한 만큼, R&D 사업의 성과창출에 대한 효과성과 효율성에 대한 논의는 다양하게 이루어지고 있다. 하지만 많은 연구들이 특허 건수, 논문 건수, 기술이전 건수 등의 양적성과 측정항목에 집중하고 있다. R&D 사업의 목표와 실제 성과 간의 연계성에 대한 부분에 대한 검토가 미진하고, 단순히 양적인 측정에만 집중하는 모습 때문에 R&D 사업의 효율성과 질(quality)·가치(value)에 대한 고려가 필요하다는 문제들이 제기되고 있다. 그래서 국가혁신사업으로 추진 확대되고 있는 기후 R&D 사업과 관련된 사업 추진 목표와 성과 창출 간의 연계성을 검토하는 것은 미래 가치창출에 대한 방향 설정을 위해 현재 시점에서 필요한 중요 연구주제라고 할 수 있다. 본 연구는 국가 기후기술 분야 중 온실가스 감축 부문에서의 R&D 사업의 연구목표와 연구내용을 조망하고, R&D 사업에서 도출된 주요 성과인 특허를 텍스트 마이닝(토픽모델링)을 활용하여 내용분석함으로써 R&D를 통한 정책적 목표가 특허 성과를 통해 실제로 구체화되었는지 파악하였다. 그리고 이를 바탕으로향후 기후기술 분야의 R&D 사업에 대한 정책적 시사점을 제시하였다.

지수창함수를 사용한 임팩트햄머 실험에서 주파수응답함수의 왜곡과 개선책

안세진,정의봉 한국소음진동공학회 2003 한국소음진동공학회 논문집 Vol.13 No.5

Exponential window function Is widely used In impact hammer testing to reduce leakage error as well as to get a good S/N ratio. The larger its decaying rate is, the more effectively the leakage errors are reduced. But if the decay rate of the exponential window is too large, the FRF is distorted. And the modal parameters of the system can not be exactly identified by modal analysis technique. Therefore, it is a difficult problem to determine proper decay rate in impact hammer testing. In this paper, amount of the FRF distortion caused by exponential window is theoretically uncovered. A new circle fitting method is also proposed so that the modal parameters are directly extracted from impulse response spectrum distorted by the exponential-windowed impulse response data. The results by the conventional and proposed circle fitting method are compared through a numerical example.

지역에 따른 소규모사업장의 산업안전보건 수요 예측

안세진,주영수,정윤경,임준 대한직업환경의학회 2013 대한직업환경의학회 학술대회 논문집 Vol.2013 No.11

인체진동 측정 및 평가 - ISO 2631

안세진 한국소음진동공학회 2014 소음 진동 Vol.24 No.5