• Journal of Acupuncture Research
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• 제40권1호
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• pp.44-52
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• 2023

Background: Previous studies have investigated technology-aided needling training systems for acupuncture on phantom models using various measurement techniques. In this study, we developed and validated a vision-based needling training system (noncontact measurement) and compared its training effectiveness with that of the traditional training method. Methods: Needle displacements during manipulation were analyzed using OpenCV to derive three parameters, i.e., needle insertion speed, needle insertion angle (needle tip direction), and needle insertion length. The system was validated in a laboratory setting and a needling training course. The performances of the novices (students) before and after training were compared with the experts. The technology-aided training method was also compared with the traditional training method. Results: Before the training, a significant difference in needle insertion speed was found between experts and novices. After the training, the novices approached the speed of the experts. Both training methods could improve the insertion speed of the novices after 10 training sessions. However, the technology-aided training group already showed improvement after five training sessions. Students and teachers showed positive attitudes toward the system. Conclusion: The results suggest that the technology-aided method using computer vision has similar training effectiveness to the traditional one and can potentially be used to speed up needling training.

• 소성∙가공
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• 제32권1호
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• pp.20-27
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• 2023

In this study, the deformation of materials was measured using the video and tracking API of OpenCV. Circular markers attached to the material were selected the region of interests (ROIs). The position of the marker was measured from the area center of the circular marker. The position and displacement of the center point was measured along the image frames. For the verification, tensile tests were conducted. In the tensile test, four circular markers were attached along the longitudinal and transverse directions. The strain was calculated using the distance between markers both in the longitudinal and transverse direction. As a result, the stress-strain curve obtained using machine vision is compared to the stress-strain curve obtained from the DIC results. RMSE values of the strain from the machine vision and DIC were less than 0.005. In addition, as a measurement example, a bending angle and springback measurement according to bending deformation, and a moving position measurement of a punch, a blank holder, and a die by time change were performed. Using the proposed method, the deformation and displacement of the materials were measured precisely and easily.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2023년도 봄 학술논문 발표대회
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• pp.381-382
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• 2023

Frequent accidents occur when workers at construction sites leave the safety zone, and particularly in the past 5 years, 9 fatal accidents occurred at the Korea Railroad Corporation due to train accidents on other tracks during track work. With the Severe Accident Punishment Act taking effect in January 2022, it is a priority to secure a safe work environment for workers at industrial (construction) sites. Therefore, there is a need to manage workers' departure from the safety zone (construction zone) and to facilitate communication within the construction zone. In this study, a mobile edge computing CCTV system is proposed that uses geofencing to determine whether workers are working in the danger zone, which can judge and respond in real-time to the ever-changing field environment. The proposed system is mobile and flexible, rather than server-based fixed CCTV. However, since it is designed mainly based on images, it has limitations in recognition rate depending on the environment such as distance, viewing angle, and illumination. As a way to compensate for this, it is required to develop more reliable equipment by combining technologies such as LiDAR and Radar.

• 한국포장학회지
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• 제29권1호
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• pp.35-41
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• 2023

수경재배한 미니 파프리카 '뉴라온레드'을 골판지 골판지 박스로 포장하여 저장 시, 온도조건 별(5℃, 10℃, 15℃와 20℃) 저장에 따른 특성 변화를 조사하였다. 일반적으로 파프리카는 10℃에서 저장이나 유통이 적절한 것으로 알려져 있으나, 국내 미니 파프리카는 상온에서 온도관리를 하지 않고 수확후 관리가 이루어지고 있었다. 미니 파프리카 '뉴라온레드'의 외관변화는 저장온도 5℃, 10℃와 15℃에서 비슷한 경향으로 나타나는데, 저장온도 10℃에서 상품성 유지기간이 가장 길었다. 저장온도 20℃에서는 다른 저장온도에서보다 급격한 외관변화로 인해 상품성 감소로 선도를 유지하는 기간이 짧아졌다. 생체중량 변화는 저장온도20℃가 저장온도 5℃~15℃와 차이를 보였으며, 저장기간이 지속될수록 격차가 더 커졌다. 생체중량 변화에서 저장온도 5℃~15℃에서는 유사한 경향을 보였다. 미니 파프리카 저장 중 경도 감소 정도는 온도에 따라 영향을 받아, 20℃에서 가장 커서 경도가 낮아졌으며, 다른 저장온도에서 저장 종료 시 저장온도 10℃에서 다소 높은 경도 유지의 경향을 보였다. Hue angle 변화는 저장초기부터 차이를 인지할 수 있었는데, 저장온도 15℃와 20℃에서 변화폭이 저장온도 5℃와 10℃에서보다 커서, 낮은 수준을 보였다. 그러나 미니 파프리카의 저장온도에 따른 가용성 고형분 함량(SSC) 변화는 저장온도에 따른 영향이 불분명한 것으로 나타났다. 수경재배한 미니 파프리카의 저장온도에 따른 수확후 특성은 높은 저장온도에서 모든 변화량이 크고 선도 감소가 커서, 현행의 상온 유통을 개선한 온도관리가 필요한 것으로 보인다. 다른 저장온도인 15℃와 20℃에서보다 5℃와 10℃에서 품질변화폭이 적어, '뉴라온레드'의 수확후 상품성 유지에 효과적인 관리온도로 판단된다. 본 연구를 통하여 미니 파프리카 '뉴라온레드'의 수확후 관리에 필요한 적정온도를 제시하였으며, 향후 다른 품종으로까지 연구를 확대하여 미니 파프리카의 관리를 일반화된 결과를 제시하여 보편적 관리기술로 정착화가 필요한 것으로 보인다.

• 생물환경조절학회지
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• 제27권2호
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• pp.125-131
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• 2018

배추를 저장하는 동안 품질을 유지하기 위한 방안으로 1-methylcyclopropene(1-MCP) 처리효과를 확인하였다. 수확된 배추는 즉시 실험실로 옮겨와 4개의 그룹(차압예냉 (forced-air cooling, FAC) 처리구, FAC + 0.03mm LLDPE film(Liner) 처리구, $FAC+2{\mu}L{\cdot}L^{-1}$ 1-MCP(1-MCP) 처리구, FAC + 1-MCP + Liner 처리구)으로 분류하여 각각의 처리를 실시한 후 $2^{\circ}C$, 95% RH 저온에서 저장하였다. 저장중 품질변화는 무게 감모율, 가용성 고형물 함량, 경도, 그리고 색도($CIE\;L^*$, $a^*$, $b^*$, chroma, hue angle)를 통해 확인하였다. 저장기간 동안 각 실험구의 감모율은 Liner 처리에 의해서 감소하였다. 저장기간 6주가 경과되면 FAC + 1-MCP + Liner 처리구는 12.5%의 감모율을 보이면서 다른 처리구들에 비해서 감모율을 최소화하였다. 가용성 고형물의 함량은 수확 시 $2.5^{\circ}Brix$였으며, 저장기간이 3주 경과되면서 FAC + 1-MCP + Liner 처리구에서 수확 시의 값이 유지된 반면, 다른 처리구 들은 증가하였다. 배추의 경도는 수확 직후 24.0N 이었으며, FAC + 1-MCP + Liner 처리구에서 저장 6주 경과 후 22.6N으로 수확 당시의 경도가 유지되는 경향을 보였다. 저장 기간 동안 배춧잎의 색 변화는 $CIE\;a^*$와 hue angle 값으로 확인할 수 있으며, 1-MCP 만을 처리할 경우에는 색도 변화에 영향을 미치지 않는 반면 1-MCP를 처리한 다음 Liner 포장을 실시하면 $CIE\;a^*$와 hue angle의 변화를 최소화 시키면서 수확 당시의 색도를 유지시킬 수 있었다. 이상의 결과에서 1-MCP 처리는 배추 력광 품종 저장에는 효과가 미비하나, Liner와 함께 처리할 경우 6주까지 품질유지가 가능하였다.

• 한국지반공학회지:지반
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• 제10권4호
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• pp.83-102
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• 1994

건조모래의 응력이력에 따른 Ko 값을 관찰하기 위하여 압밀링 형태의 Ko시험기를 새로이 고안하였으며, 이 시험기를 사용하여 수평응력을 측정하였다. 본 실험을 위하여 총 2형태의 단주기 Ko 재하/제하시험이 4종류의 상대밀도에 대하여 수행하였다. 실험결과, 처녀재하 시의 정지토압계수 K.은 모래의 내부마촹각 U'의 함수로서 K.. : 1-0.914sin0'와 같은 관계식을 얻을 수 있었다. 처녀제하 시의 정지토압계수 Kou는 Ko.과 과압밀비(OCR)의 함수로서 Ko.=Ko. (OCR)a으로 표시할 수 있으며, 지수 a는 대체로 상대밀도가 클수록 증가하는 경향을 보인다. 처녀재재하 시의 정지토압계수 Kor은 연직응력 Qv'가 증가함에 따라 쌍곡선 형태로 감소한다. 그리고 처녀재재하 시의 응력경로는 최소제하응력의 크기에 무관하게 최대선행점으로 복귀하며, 이곡선의 기울기 mr은 OCR이 클수로 증가한다.

• 한국자동차공학회논문집
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• 제18권1호
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• pp.1-7
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• 2010

The paper proposes a multi-body dynamic simulation to numerically evaluate the generated axial force(G.A.F) and plunging resistant force(P.R.F) practically related to the shudder and idling vibration of an automobile. A numerical analysis of two plunging types of CV joints, tripod joint(TJ) and very low axial tripod joint(VTJ), is conducted using the commercial program DAFUL. User-defined subroutines of a friction model illustrating the contacted parts of the outboard and inboard joint are subsequently developed to overcome the numerical instability and improve the solution performance. The Coulomb friction effect is applied to describe the contact models of the lubricated parts in the rolling and sliding mechanisms. The numerical results, in accordance with the joint articulation angle variation, are validated with experimentation. The offset between spider and tulip housing is demonstrated to be the critical role in producing the 3rd order component of the axial force that potentially causes the noise and vibration in vehicle. The VTJ shows an excellent behavior for the shudder when compared with TJ. In addition, a flexible nonlinear contact analysis coupled with rigid multi-body dynamics is also performed to show the dynamic strength characteristics of the rollers, housing, and spider.

• 한국생산제조학회지
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• 제19권6호
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• pp.883-888
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• 2010

This study have goal with conceptual design for Offshore Structures of high pressure control valve for localization. Ball valve for development accomplished with flow analysis based on provision of ANSI B16.34, ANSI B16.10, ANSI B16.25 In order to localize the Offshore Structures high pressure control valve. Numerical simulation using CFD (Computational Fluid Dynamic) in order to predict a mass flow rate and a flow coefficient form flow dynamic point of view. The working fluid assumed the glycerin (C3H8O3). The valve inlet and outlet setup a pressure boundary condition. The outlet pressure was fixed by atmospheric pressure and calculated until increasing 1bar to 10bar. CFD analysis used STAR-CCM+ which is commercial code and Governing equations were calculated by moving mesh which is rotated 90 degrees when ball valve operated opening and closing in 1 degree interval. The result shows change of mass flow rate according to opening and closing angle of valve, Flow decrease observed open valve that equal percentage flow paten which is general inclination of ball valve. Relation with flow and flow coefficient can not be proportional according to inlet pressure when compare with mass flow rate. Because flow coefficient have influence in flow and pressure difference. Namely, flow can be change even if it has same Cv value. The structural analysis used ANSYS which is a commercial code. Stress analysis result of internal pressure in valve showed lower than yield strength. This is expect to need more detail design and verification for stem and seat structure.

• Journal of Microbiology and Biotechnology
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• 제18권1호
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• pp.145-152
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• 2008

A cell-based in vitro exposure system was developed to determine whether oxidative stress plays a role in the cytotoxic effects of volatile organic compounds (VOCs) such as benzene, toluene, xylene, and chlorobenzene, using human epithelial HeLa cells. Thin films based on cysteine-terminated synthetic oligopeptides were fabricated for immobilization of the HeLa cells on a gold (Au) substrate. In addition, an immobilized cell-based sensor was applied to the electrochemical detection of the VOCs. Layer formation and immobilization of the cells were investigated with surface plasmon resonance (SPR), cyclic voltammetry (CV), and electrochemical impedance spectroscopy (EIS). The adhered living cells were exposed to VOCs; this caused a change in the SPR angle and the VOC-specific electrochemical signal. In addition, VOC toxicity was found to correlate with the degree of nitric oxide (NO) generation and EIS. The primary reason for the marked increase in impedance was the change of aqueous electrolyte composition as a result of cell responses. The p53 and NF-${\kappa}B $ downregulation were closely related to the magnitude of growth inhibition associated with increasing concentrations of each VOC. Therefore, the proposed cell immobilization method, using a self-assembly technique and VOC-specific electrochemical signals, can be applied to construct a cell microarray for onsite VOC monitoring.

• 대한설비공학회:학술대회논문집
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• 대한설비공학회 2008년도 하계학술발표대회 논문집
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• pp.1195-1200
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• 2008

This study have goal with conceptual design for Offshore Structures of high pressure control valve for localization. Ball valve for development accomplished with flow analysis based on provision of ANSI B16.34, ANSI B16.10, ANSI B16.25 In order to localize the Offshore Structures high pressure control valve. Numerical simulation using CFD(Computational Fluid Dynamic) in order to predict a mass flow rate and a flow coefficient form flow dynamic point of view. The working fluid assumed the glycerin($C_3H_8O_3$). The valve inlet and outlet setup a pressure boundary condition. The outlet pressure was fixed by atmospheric pressure and calculated until increasing 1bar to 10bar. CFD analysis used STAR-CCM+ which is commercial code and Governing equations were calculated by moving mesh which is rotated 90 degrees when ball valve operated opening and closing in 1 degree interval. The result shows change of mass flow rate according to opening and closing angle of valve. Flow decrease observed open valve that equal percentage flow paten which is general inclination of ball valve. Relation with flow and flow coefficient can not be proportional according to inlet pressure when compare with mass flow rate. Because flow coefficient have influence in flow and pressure difference. Namely, flow can be change even if it has same Cv value. The structural analysis used ANSYS which is a commercial code. Stress analysis result of internal pressure in valve showed lower than yield strength. This is expect to need more detail design and verification for stem and seat structure.