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곽경민,노영주,Gwak, Kyung-Min,Rho, Young J. 한국인터넷방송통신학회 2021 한국인터넷방송통신학회 논문지 Vol.21 No.4
4차 산업혁명 시대에 맞추어 인공지능 기술은 눈에 띄게 발전하고 있다. 그 중 CNN 등을 활용한 시각 데이터 기반의 인공지능이 활발히 연구 진행 중이다. 시각 기반 모델 중 하나인 U-net은 Semantic Segmentation에 강한 정확도를 보이고 있다. 기존의 U-net을 활용하여 여러 가지 연구들이 진행 되어왔지만 가스, 연기와 같이 외곽선이 뚜렷하지 않은 연구들은 아직 부족한 실정이다. 또한 이와 대조적으로 가스, 연기 탐지에 대해 많은 연구들이 진행이 되어왔지만 U-net 등을 활용하여 단순한 Detection이 아닌 Segmentation 연구는 부족하다. 이를 토대로 본 연구에서는 U-net을 활용하여 가스, 연기 등을 탐지하는 연구를 진행하였다. 본 논문에서는 설정한 실험환경에서 3D camera를 활용하여 데이터를 수집하고 학습 및 테스트 셋을 생성한 방법을 기술하고, U-net을 적용한 방법과 얻은 결과를 검증한 내용을 서술하고, 마지막으로 활용방안 등에 대하여 논하였다. Artificial intelligence technology is developing as it enters the fourth industrial revolution. Active researches are going on; visual-based models using CNNs. U-net is one of the visual-based models. It has shown strong performance for semantic segmentation. Although various U-net studies have been conducted, studies on tracking objects with unclear outlines such as gases and smokes are still insufficient. We conducted a U-net study to tackle this limitation. In this paper, we describe how 3D cameras are used to collect data. The data are organized into learning and test sets. This paper also describes how U-net is applied and how the results is validated.
레이놀즈 수가 낮은 영역에서 와류발생기를 적용한 핀-관 열교환기 성능평가
곽경민,송길달 대한설비공학회 2006 설비공학 논문집 Vol.18 No.2
The present paper reports the method for evaluation of heat-transfer performance of finned tube heat exchangers in a low Reynolds number regime(Re=160∼800) and also reports the data of heat transfer and pressure loss taken from a finned tube heat exchanger with/without vortex generators(VGs) installed as a heat-transfer enhancement device. The evaluation is based on the modified single blow method conducted in a specially designed low Reynolds number duct. Three different test core geometries, i.e., fin only, fin-tube without VGs and that with VGs, are studied here. The data of heat transfer and pressure loss taken from the fin only geometry agree well with the empirical correlations, thus validating the present method as used for low Reynolds number regime. The data taken from the finned tube geometries with and without VGs are presented and compared to examine the effect of VGs in the low Reynolds number regime.
곽경민,배철호 대한기계학회 2009 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.23 No.6
Three types of flow passage structure of a total heat exchanger (perforated type, slit type, and embossed and perforated type ) are studied to enhance the heat exchange performance of a heat recovery ventilation system (total heat exchanger). The perforated type has four punched rows of 6mm holes in the flow passage channel, and the slit type has six processed rows of 40mm length. The embossed and perforated type has holes of about 1mm diameter and protrusions of about 0.2mm height on all surfaces. The heat exchange efficiency of the modified total heat exchanger was compared to that of a general total heat exchanger with a smooth surface. The Korean Standard (KS) heat recovery ventilator test condition was applied for tests. In the case of cooling operation based on a typical Reynolds number of 140 (typical air flow rate of 100 m3/hr), the perforated type, slit type, and embossed and perforated type showed temperature efficiency improvement of 1.2%, 2.5%, and 5.0%; latent efficiency improvement of 18.0%, 32.3%, and 24.5%; and enthalpy efficiency improvement of 7.9%, 11.5%, and 11.2%, respectively. The corresponding improvements of heating operation were 3.0%, 3.4%, and 4.0%; 5.0%, 6.6%, and 18.7%; 3.2%, 4.3%, and 7.7%, respectively. On the other hand, the air pressure drop throughout the modified flow passage of the total heat exchanger increased by up to 1.7% at the typical Reynolds number of 140, from the air pressure drop of the regular total heat exchanger.