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이정준(J. J. Lee),주병현(B. H. Joo),이병채(B. C. Lee) 한국정밀공학회 2004 한국정밀공학회 학술발표대회 논문집 Vol.2004 No.10월
Generally, in case the natural frequency of vehicle components is larger than the reversing frequency of load history, we can obtain the analysis results with small errors. But in case of having the low natural frequency, we must avoidably carry out the dynamic analysis, and it requires much time and storage. Specially executing the fatigue analysis for vehicle components requires more time. To this end, it is not easy that we accomplish the optimization considering fatigue for the vehicle component based on the dynamic analysis. In this research we introduce an efficient method which performs the fatigue analysis based on the dynamic analysis. Finally as making the response surface we optimize the vehicle component under dynamic fatigue.
스마트센서시스템의 기능안전을 위한 Lora 통신 필드 적합성 테스트 연구
오봉식(Bong S. Oh),박상철(Sang C. Park),장중순(Joong S. Jang),이정준(Jung J. Lee) 한국신뢰성학회 2022 신뢰성응용연구 Vol.22 No.2
Purpose: Three types of LPWA LoRa module were investigated as candidate smart sensor systems in a smart factory. A long-distance communication success test was conducted to determine which module type best satisfied functional safety requirements. Methods: The three types of LoRa communication module considered in this paper were 1. sLory, 2. RYLR890 using UART interface and 3. P2P UART communication module RAK811. A communication success field demonstration test was performed at 3.24 km in the city center and in a flat area (Ansan-si). Results: The RYLR890 module type achieved communication success up to 3 km. However, the communication success rate from departure to arrival was unstable. The RAK811 achieved communication up to 2 km and the field test demonstrated that the transmission/reception performance was stable from departure to arrival. Conclusion: Three types of LoRa module were selected for LPWA and the worlds first field verification test was conducted. It was verified that the RAK811 model’s field communication success rate meets functional safety requirements. However, it is still necessary to ensure the functional safety of sensor-node, communication system and PHM technology by examining structural aspects such as longitudinal axis, lateral side and height.
고승기(Koh.S.K),류창훈(Ryu.C.H),이정준(Lee.z.J),나의균(Na.E.G),백태현(Baek.T.H),전경락(Jeon.K.L.) 대한기계학회 2003 대한기계학회 춘추학술대회 Vol.2003 No.11
A failure analysis of holddown spring screw was performed using fracture mechanics approach. The<br/> spring screw was designed such that it was capable of sustaining the loads imposed by the initial<br/> tensile preload and operational loads. In order to investigate the cause of failure, a stress analysis of<br/> the top nozzle spring assembly was done using finite element analysis and a life prediction of the<br/> screw was made using a fracture mechanics approach. The elastic-plastic finite element analysis<br/> showed that the local stresses at the critical regions of head-shank fillet and thread root significantly<br/> exceeded than the yield strength of the screw material, resulting in local plastic deformation. Primary<br/> water stress corrosion cracking life of the Inconel 600 screw was predicted by using integration of<br/> the Scott model and resulted in 1.42 years, which was fairly close to the actual service life of the<br/> holddown spring screw.
오봉식(Bong S. Oh),박상철(Sang C. Park),장중순(Joong S. Jang),이정준(Jung J. Lee) 한국신뢰성학회 2021 신뢰성응용연구 Vol.21 No.3
Purpose: Reliability and safety-based message queuing telemetry transport (MQTT) communication applications and artificial intelligence (AI)-smart sensor development are considered in the smart factory to ensure competitiveness by minimizing risks in manufacturing, pre-failure diagnosis, and failure prediction prognostics and health management (PHM) technology. Methods: The algorithm was implemented to ensure that the MQTT Publisher software technology application conforms to the standard by applying it as a process design method in the smart factory. In the functional safety standard and reliability prediction methods, safety risk data were collected, analyzed, and verified as an evaluation procedure in the smart factory. Results: The performance of MQTT communication as well as the safety data collection and database (DB) storage functions were confirmed in the smart factory. The contents of the literature search were confirmed in relation to the evaluation of the reliability feature extraction factors and functional safety-related failure prognosis parameters of the AI-smart sensor, center control server, monitoring-related design, and development products to be used as the basis for reliability and safety in smart factories. Conclusion: The process of sensor input using Arduino, the transmission of measured values, and storage of collected data into a DB using the resistive temperature device was developed as a software algorithm and demonstrated in the smart factory using MQTT communication. According to a literature search related to priority-based MQTT, this partial application can be effectively used in small and medium-sized smart factories that require a real-time priority algorithm. It can be used as a price-competitive communication method.
광도플러단층촬영장치를 이용한 생체내 혈류 유동가시화에 관한 연구
남후중(H.J. Nam),심명권(M.G. Sim),이정준(J.J. Lee),타치아흐메드쳄마(T.A. Cheema),박철우(C.W. Park) 대한기계학회 2012 대한기계학회 춘추학술대회 Vol.2012 No.11
Blood flow visualization and velocity field measurement are very difficult to be carried out in vivo compared to those of normal fluid flow measurement although they can employ viewing scope and tracer. In this study, we employ optical Doppler tomography (ODT) to visualize the blood vessels of chicken embryo, so that it can lead to yield much reliable data compared to other methods in vivo.