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합성곱 신경망 알고리즘을 활용한 베어링 다중 고장 진단 모델 개발
이상원(S. W. Lee),이창호(C. H. Lee),김진우(J. W. Kim),김수종(S. J. Kim) Korean Society for Precision Engineering 2021 한국정밀공학회 학술발표대회 논문집 Vol.2021 No.11월
회전 기계에서 베어링은 전체 기계시스템의 구동 및 제어에 핵심적인 역할을 하므로 장비의 안전하고 지속적인 작동을 위해서는 베어링의 유지 보수 및 상태 모니터링이 필수적이다. 본 연구에서는 베어링의 예상치 못한 파손으로 인한 기계시스템의 손상에 대비하기 위해, 대표적인 딥러닝 알고리즘인 Convolutional Neural Networks (CNN)을 활용한 베어링의 고장 상태 및 고장 종류 진단 모델을 개발하였다. 베어링 시뮬레이터를 사용하여, 정상 및 고장 상태의 베어링의 회전운동을 구현하였으며, 각 베어링 상태에서의 신호 데이터는 2 개의 가속도 센서를 X, Y 축에 고정시켜 수집하였다. 고장 상태는 4 종류로 볼, 케이지, 외륜, 내륜 고장을 부품에 모사하였으며, 정상 및 고장 상태의 데이터 세트는 각각 500 개씩 수집하였다. 베어링 상태의 시계열 데이터 신호는 Short Time Fourier Transform (STFT) 기법으로 전처리 하였고 두 단계의 CNN 알고리즘을 활용하여 진단 모델을 개발하였다. 첫 번째 단계에서는 정상 및 고장 상태를 분류할 수 있는 모델로 설계하였고 두 번째 단계에서는 고상 상태로 분류된 데이터 세트에 대해서 4가지의 고장 종류를 분류할 수 있는 모델로 설계하였다. 각 단계에서 사용된 CNN 알고리즘 설계는 동일하며, K-fold Cross Validation 을 통해 개발된 모델에 대한 검증을 수행하였다.
문중문고(門中文庫)에 대하여 -특(特)히 수봉정사(壽峰精舍).영규헌(映奎軒) 우문고(雨文庫)를 중심(中心)으로-
이춘희,Lee, Choon-Hee 한국비블리아학회 1974 한국비블리아학회지 Vol.2 No.-
The libraries that existed during the latter period of the Yi Dynasty may be categorized into four types: the royal library, the school library, the clan community library, and the private library. Of these, the clan community library has yet received very little attention in the study of Korean libraries. In this study the author discusses the purposes, functions, and collections of the clan community library to clarify what that particular type of old libraries in Korea was. The clan community library functioned within individual clan communities to give young people Korean traditional education protecting them from possible influences of. Japanese version of Western scholarship which had threatened the traditional value systems of the society. The author believes that the clan community library was a unique community institution created by Korean people, and the Korean public library movement should trace its origin back to the activities of the libraries. Unfortunately the growing suppression and control of the Japanse colonial regime upon the traditional schools made the purposes and development of the clan community library movement a tragic experience before its flowering. The clan community library was a Korean native public library which came out in response to a historical situation and community need. It may deserve more attention in future study of the national library movement of Korea.
이춘희,Lee Choon Hee 한국문헌정보학회 1980 한국문헌정보학회지 Vol.7 No.-
Because of the changes made in the modes of cataloguing and classification in its long history, the present catalogue of the National Central Library has become complicated and provides an inadequate guide to its collection. There can be no doubt that this is a serious deficiency in a closed access library since materials housed in the library are virtually inaccessible to unskilled readers. The whole breakdown of the efficiency of the catalogue is emminent and will ultimately create the most serious problems for the library. The main purpose of this survey is: (a) to identify problem areas created by the frequent changes in the cataloguing and classifying principles in the library and (b) to grope a rational direction for the future development. Analysing the various classification schemes and cataloguing rules adopted in processing materials (mainly books) in the library, the following conclusions have been made. A. The library adopted five different clasification schemes in different periods, of which KDCP was used for the most part of its collection. KDCP is recommended to use for the future colletion. A classification development office is recommended to be established within the library, of which the main function is to revise the KDCP in collaboration with the appropriate committee of the Korean Library Association. B. The present practice in the library is to apply three different cataloguing rules and two different author notation tables to the Oriental, classical, and Western collections. Efforts should be made to find out an efficient system so that this variety is simplified. An alphabetical index should be added to the classified catalogue, and improvements are required in the Japanese collection. C. The technical services division is inadequately staffed. The staff should be sufficiently numerous and specially qualified. D. The present financial support for the technical services of the library is inadequate. Sufficient financial provision should be made to ensure the effective work. E. A feasibility study should be carried out to develop a computer processing system for providing machine-readable catalogue records on magnetic tape for use by the library community in Korea.