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F-RPN(Failure-RPN)을 이용한 장비 고장률 개선 연구: 반도체 식각 공정을 중심으로
이형근,홍용민,강성우,Lee, Hyung-Geun,Hong, Yong-Min,Kang, Sung-Woo 대한안전경영과학회 2021 대한안전경영과학회지 Vol.23 No.3
The purpose of this study is to present a novel indicator for analyzing machine failure based on its idle time and productivity. Existing machine repair plan was limited to machine experts from its manufacturing industries. This study evaluates the repair status of machines and extracts machines that need improvement. In this study, F-RPN was calculated using the etching process data provided by the 2018 PHM Data Challenge. Each S(S: Severity), O(O: Occurence), D(D: Detection) is divided into the idle time of the machine, the number of fault data, and the failure rate, respectively. The repair status of machine is quantified through the F-RPN calculated by multiplying S, O, and D. This study conducts a case study of machine in a semiconductor etching process. The process capability index has the disadvantage of not being able to divide the values outside the range. The performance of this index declines when the manufacturing process is under control, hereby introducing F-RPN to evaluate machine status that are difficult to distinguish by process capability index.
열화상 이미지 분석을 통한 배전 설비 공정능력지수 감지 시스템 개발
이형근 ( Hyung-geun Lee ),홍용민 ( Yong-min Hong ),강성우 ( Sung-woo Kang ) 한국품질경영학회 2021 품질경영학회지 Vol.49 No.3
Purpose: The purpose of this study is to propose a system predicting whether an electricity distribution system is abnormal by analyzing the temperature of the deteriorated system. Traditional electricity distribution system abnormality diagnosis was mainly limited to post-inspection. This research presents a remote monitoring system for detecting thermal images of the deteriorated electricity distribution system efficiently hereby providing safe and efficient abnormal diagnosis to electricians. Methods: In this study, an object detection algorithm (YOLOv5) is performed using 16,866 thermal images of electricity distribution systems provided by KEPCO(Korea Electric Power Corporation). Abnormality/ Normality of the extracted system images from the algorithm are classified via the limit temperature. Each classification model, Random Forest, Support Vector Machine, XGBOOST is performed to explore 463,053 temperature datasets. The process capability index is employed to indicate the quality of the electricity distribution system. Results: This research performs case study with transformers representing the electricity distribution systems. The case study shows the following states: accuracy 100%, precision 100%, recall 100%, F1-score 100%. Also the case study shows the process capability index of the transformers with the following states: steady state 99.47%, caution state 0.16%, and risk state 0.37%. Conclusion: The sum of caution and risk state is 0.53%, which is higher than the actual failure rate. Also most transformer abnormalities can be detected through this monitoring system.
접착재 종류와 정착구 유무에 따른 탄소막대 매립보강 RC보의 휨 거동에 관한 실험적 연구
김성원,이형근,여환준,박성무,Kim, Sung-Won,Lee, Hyung-Geun,Yeo, Hwan-Jun,Park, Sung-Moo 한국공간구조학회 2014 한국공간구조학회지 Vol.14 No.4
For the last decade many bridges and buildings have experienced flexural strengthening with the fiber reinforced polymer(FRP) bonding system, demands for increasing heavy traffic loads and the changing of the code application. Of the many strengthening systems, NSM(near surface mounted) system with FRP has become attractive and popular way of strengthening for the existed RC structures and many studies and applications of this technique have significantly increased all over the world. Meanwhile, polymer mortar that contains much of the same ingredients as cement but includes the addition of certain polymer resins for enhancing desired physical properties, has been used as an alternative adhesive. This paper focuses on flexural behaviour of CFRP-bar NSM system with variables such as kinds of adhesive, anchorage, sectional aspect ratio. Based on the test results and test-to-predicted ratio, this paper provides researchers and practical engineers a fundamental knowledge and intuition.
A Case of Primary Hepatic Malignant Paraganglioma without Hypertension
Heuy Seong Lee(이희성),Hyung Geun Lee(이형근),Dong Do You(유동도),Jin Seok Heo(허진석),Seong Ho Choi(최성호),Dong Wook Choi(최동욱) 한국간담췌외과학회 2009 한국간담췌외과학회지 Vol.13 No.1
Paraganglioma is an unusual neoplasm that is embryologically derived from neural crest cells. The most common location of this neoplasm is the adrenal medulla, where these tumors are known as pheochromocytoma. It is extremely rare that paragangliomas occur in the liver. There are only 7 reports of primary hepatic paraganglioma. A 56-year-old man was referred to XX Medical Center. Hypertension was not found. He had suffered from jaundice, headache and weight loss for the 4 previous weeks, but hypertension was not present. The total bilirubin was 7.7 mg/dl and the CA19-9 level was 56.3 U/dl. The tumor was diagnosed as intrahepatic cholangiocarcinoma on the computed tomography image. After biliary drainage via endoscopic nasobiliary drainage, surgical exploration was carried out; right trisectionectomy with caudate lobectomy, portal vein resection and anastomosis were then done. The final pathological diagnosis was primary hepatic malignant paraganglioma of the intrahepatic duct. There has been no evidence of recurrence on the follow up CT images during the 24 month follow up period.
무선 센서 네트워크를 위한 효율적인 프리앰블 가상 동기화 기법을 사용하는 저전력 MAC 프로토콜 설계
이성훈(Sung-hun Lee),황세욱(Se-wook Hwang),이혁준(Hyuk-joon Lee),이형근(Hyung-geun Lee) 한국통신학회 2010 韓國通信學會論文誌 Vol.35 No.5b
무선 센서 네트워크에서 에너지효율은 중요한 이슈가 되고 있다 따라서 센서 노드들의 에너지 소모를 줄이는 MAC 프로토콜과 라우팅 기법이 필요로 한다. 본 논문에서는 X-MAC 프로토콜을 기반에 가상 동기화 기법 추가하여 주위 환경에 적응적인 센서 MAC 프로토콜을 제안한다. 가상 동기화 기법은 송신 노드가 수신 노드의 활성시간에 맞추어 데이터를 전송하여 송신 노드에서의 프리앰블 전송 횟수를 줄인다. 검증을 위해 NS-2 시뮬레이터를 사용하였으며, 가상 동기화 기법은 기존의 X-MAC보다 10%정도의 에너지 소비의 에너지 효율성을 향상시켰다. The researches about energy efficieny of wireless sensor MAC protocol is an issue in present days. Therefore, MAC and routing protocols for reducing energy consumption at sensor nodes is needed. In this study, a low-power MAC protocol for sensor network is proposed, which in based on X-MAC by exploiting virtual synchronization. The virtual synchronization technique lets senders postpone packet transmission until receivers' wake-up time, so that senders transmit only one or two short preambles. Using NS-2, a proposed MAC protocol improve the energy efficiency by 10% compared with the X-MAC protocol.