• 대한화학회지
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• 제44권6호
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• pp.541-546
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• 2000

리간드 증감 유발 형광법을 이용하여 Tb(III)-L-dopa (L-3,4-dihydroxyphenyl alanine) 착이온의 방출세기를 측정함으로써 수용액 중의 L-dopa를 정량하는 방법에 대하여 연구하였다. 들뜸파장, pH, 보조 형광증가제의 선택, Tb(III) 이온의 농도, 보조 형광증가제로 사용된 Lu(III) 이온의 농도 및 방출파장의 방출세기에 대한 영향을 조사하였다. 보조 형광증가제로서 Lu(III) 이온을 첨가하였을때 Tb(III) 이온의 방출세기가 현저히 증가함을 관찰하였고, L-dopa의 검출한계를 낮출 수 있었다. 보조 형광증가제를 첨가하지 않았을 경우에 L-dopa 검정곡선의 직선감응범위는 들뜸파장, pH 및 Tb(Ⅲ) 이온의 농도가 각각 300 nm, 8.0 및 $1.0{\times}10^{-4}$ M였을때, $5.0{\times}10^{-7}$ M~$1.0{\times}10^{-4}$ M였다. 이 조건에서의 검출한계는 $4.0{\times}10^{-8}$ M였다. 보조 형광증가제를 첨가하였을 경우에는 들뜸파장, pH, Tb(III) 이온의 농도, 보조 형광증가제로 사용된 Lu(III) 이온의 농도 및 방출파장이 각각 300 nm, 8.5, $1.0{\times}10^{-5}$ M, $1.0{\times}10^{-5}$ M 및 545 nm였을 때, 직선감응범위가 1.0×$10^{-8}$ M~2.0{\times}10^{-4}$ M였고, 이 때의 검출한계는 $1.0{\times}10^{-9}$ M였다.

• The Korean Journal of Physiology and Pharmacology
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• 제26권6호
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• pp.427-438
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• 2022

Pyroptosis, a form of cell death associated with inflammation, is known to be involved in diabetic nephropathy (DN), and discoid domain receptor 1 (DDR1), an inflammatory regulatory protein, is reported to be associated with diabetes. However, the mechanism underlying DDR1 regulation and pyroptosis in DN remains unknown. We aimed to investigate the effect of DDR1 on renal tubular epithelial cell pyroptosis and the mechanism underlying DN. In this study, we used high glucose (HG)-treated HK-2 cells and rats with a single intraperitoneal injection of streptozotocin as DN models. Subsequently, the expression of pyroptosis-related proteins (cleaved caspase-1, GSDMD-N, Interleukin-1β [IL-1β], and interleukin-18 [IL-18]), DDR1, phosphorylated NF-κB (p-NF-κB), and NLR family pyrin domain-containing 3 (NLRP3) inflammasomes were determined through Western blotting. IL-1β and IL-18 levels were determined using ELISA. The rate of pyroptosis was assessed by propidium iodide (PI) staining. The results revealed upregulated expression of pyroptosisrelated proteins and increased concentration of IL-1β and IL-18, accompanied by DDR1, p-NF-κB, and NLRP3 upregulation in DN rat kidney tissues and HG-treated HK-2 cells. Moreover, DDR1 knockdown in the background of HG treatment resulted in inhibited expression of pyroptosis-related proteins and attenuation of IL-1β and IL-18 production and PI-positive cell frequency via the NF-κB/NLRP3 pathway in HK-2 cells. However, NLRP3 overexpression reversed the effect of DDR1 knockdown on pyroptosis. In conclusion, we demonstrated that DDR1 may be associated with pyroptosis, and DDR1 knockdown inhibited HG-induced renal tubular epithelial cell pyroptosis. The NF-κB/NLRP3 pathway is probably involved in the underlying mechanism of these findings.

• Korean Journal of Acupuncture
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• 제23권1호
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• pp.1-14
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• 2006

Objectives : This research was performed to investigate the effect of invasive low level laser acupuncture therapy(LLLAT) at Yolgyol+yogu(LU7+LR5) on weight gain, food intake, food efficiency, lipid metabolism and liver function in hyperlipemia rats. Methods : Experimental groups were divided into high fat diet cup(Control group), high fat diet and 15 mW/5 min LLLAT at LU7+LR5(15 mW/5 min group), 15 mW/10 min LLLAT at LU7+LR5(15 mW/10 min group), 30 mW/5 min LLLAT at LU7+LRS(30 mW/5 min group), 30 mW/10 min LLLAT at LU7+LR5(30 mW/10 min group). LLLAT was treated at the 15,30mW-5,10min once a 2day during 5 weeks. Results : Body weight was decreased significantly in 30 mW/s min group and 30 mW/10 min group compared with control group. Food intake was decreased significantly in 15 mW/5 min group and 15 mW/10 min group compared with control group. Food efficiency was decreased significantly in 30 mW/10 min group compared with control group. In the lipid metabolism, total cholesterol, HDL-cholesterol and free fatty acid were increased significantly in 15 mW/5 min group and 30 mW/10 min group compared with control group. LDL-cholesterol was increased in 30 mW/10 min group and phospholipids was decreased significantly in all experimental group compared with control group. triglyceride was not showed significant result in all experimental group. In the liver function, AST was not showed significant result in all experimental group, ALT and ALP were increased significantly in 30 mW/10 min group, ALP was decreased in 30 mW/5 min group compared with control group. Conclusions : LLLAT at LU7 and LR5 can manage hyperlipemia by controlling body weight, food intake, food efficiency ratio and lipid metabolism.

• 한국산학기술학회논문지
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• 제18권10호
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• pp.75-80
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• 2017

본 논문에서는 딥러닝에서 활용되는 정규화(regularization) 및 항등사상(identity mapping)이 활성함수(activation function) 성능에 미치는 영향에 대해 설명한다. 딥러닝에서 활성함수는 비선형 변환을 위해 사용된다. 초기에는 sigmoid 함수가 사용되었으며, 기울기가 사라지는 기존의 활성함수의 문제점을 극복하기 위해 ReLU(Rectified Linear Unit), LReLU(Leaky ReLU), PReLU(Parametric ReLU), ELU(Exponetial Linear Unit)이 개발되었다. 활성함수와의 연구와는 별도로 과적합(Overfitting)문제를 해결하기 위해, Dropout, 배치 정규화(Batch normalization) 등의 정규화 방법들이 개발되었다. 추가적으로 과적합을 피하기 위해, 일반적으로 기계학습 분야에서 사용되는 data augmentation 기법이 활용된다. 딥러닝 구조의 측면에서는 기존에 단순히 컨볼루션(Convolution) 층을 쌓아올리는 구조에서 항등사상을 추가하여 순방향, 역방향의 신호흐름을 개선한 residual network가 개발되었다. 위에서 언급된 활성함수들은 각기 서로 다른 특성을 가지고 있으나, 새로운 정규화 및 딥러닝 구조 연구에서는 가장 많이 사용되는 ReLU에 대해서만 검증되었다. 따라서 본 논문에서는 정규화 및 항등사상에 따른 활성함수의 성능에 대해 실험적으로 분석하였다. 분석을 통해, 정규화 및 항등사상 유무에 따른 활성함수 성능의 경향을 제시하였으며, 이는 활성함수 선택을 위한 교차검증 횟수를 줄일 수 있을 것이다.

• 한국멀티미디어학회논문지
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• 제21권10호
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• pp.1142-1149
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• 2018

Recently, computer vision application is increasing by using CNN which is one of the deep learning algorithms. However, CNN does not provide perfect classification performance due to gradient vanishing problem. Most of CNN algorithms use an activation function called ReLU to mitigate the gradient vanishing problem. In this study, four activation functions that can replace ReLU were applied to four different structural networks. Experimental results show that ReLU has the lowest performance in accuracy, loss rate, and speed of initial learning convergence from 20 experiments. It is concluded that the optimal activation function varied from network to network but the four activation functions were higher than ReLU.

• 대한기계학회논문집A
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• 제33권5호
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• pp.508-513
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• 2009

Friction is an important factor for precise position tracking control of servo systems. Servo systems with highly nonlinear friction are sensitive to the variation of operating condition. To overcome this problem, we use the LuGre friction model which can consider dynamic characteristics of friction. The LuGre friction model is used as a feed-forward compensator to improve tracking performance of servo systems. The parameters of the LuGre friction model are identified through experiments. The experimental result shows that the tracking performance of servo systems with higherly nonlinear friction can be improved by using feed-forward friction compensation.

• 한국전산유체공학회:학술대회논문집
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• 한국전산유체공학회 2003년도 추계 학술대회논문집
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• pp.49-55
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• 2003

A comprehensive study has been made for the investigation of the convergence characteristics of the LU scheme for the Euler equations using von Neumann stability analysis. The stability results indicate that the convergence rate is governed by a specific parameter combination. Based on this insight it is shown that the LU scheme will not suffer convergence deterioration at any grid aspect ration if the local time step is defined using appropriate parameter combination. The numerical results demonstrate that this time step definition gives uniform convergence for grid aspect ratios from one to $1\times10^4$.

• Korean Journal of Acupuncture
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• 제38권4호
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• pp.235-249
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• 2021

Objectives : Acupoint LU6 (Gongchoe) is known as an acupoint for the treatment of pain and bleeding caused by hemorrhoids. The purpose of this study was to critically review acupoint LU6 for treating hemorrhoids. Methods : We searched both ancient and modern literature of acupuncture and moxibustion using keywords "Gongchoe" and "hemorrhoids". We further performed an online ancient literature search for crosscheck. The searched literature was stratified by country (Korea, China, and Japan), and data were organized chronologically. Concerning literature related to hemorrhoids, data based on acupuncture treatment were compiled. Results : The bone proportional measurement of the forearm had been 12.5 cun until the Qing Dynasty but was recorded as 10 cun in "Shinkyushinzui," and the majority of modern Japanese and Korean literature indicated it as 10 cun. Gongchoe for treating hemorrhoids has been reported in the literature, including "Shinkyushinzui" (Japan, 1941), "Shiyoungzongguozhenjiujingxuexue" (Taiwan, 1963), "Gyeonghyeolhak" (Korea, 1971), and "Jinzhenmeihuashichao" (China, late Qing dynasty), but except "Jinzhenmeihuashichao", the location is different from the World Health Organization (WHO) standard acupoint location as it is 7 cun from the wrist out of 10 cun of the forearm bone proportional measurement. In addition, classical guides published until the Qing Dynasty did not report acupoint LU6 for the treatment of hemorrhoids. Conclusions : It is necessary to distinguish between Gongchoe in "Shinkyushinzui" and LU6 in WHO standard acupuncture point locations. Gongchoe (LU6)'s primary treatment for hemorrhoids has not been described in the classical literature, and further clinical evidence is needed to support it. When using Gongchoe for hemorrhoids, we should consider that the location of Gongchoe is closer to the LU5 than the standard acupuncture point locations and it is meaningful not only for treatment but also for diagnosis.

• Korean Journal of Acupuncture
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• 제37권1호
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• pp.31-36
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• 2020

Objectives : The purpose of this study is to review needling depth and location of LU7, BL62 and KI6 by the medical classics' records. Methods : 1. We researched the medical classics describing LU7, KI6 and BL62, and reorganized data about the location and needling depth. 2. We compared the medical classics' records on LU7, KI6 and BL62 with description of WHO standard acupuncture point location. 3. We reviewed different location and needling depth of LU7, BL62, and KI6 recorded in the medical classics with the anatomical structure. Results : 1. The common needling depth of LU7 is about 0.2 chon. But in some medical classics, the depth of LU7 is 0.8 chon. Needling depth of LU7 varied depending on the patient's hand posture. In the 'half-up' position with the thumb upward, it is possible to stimulate acupuncture on LU7 by 0.8 chon because there is a space between the tendons. 2. In WHO standard acupuncture point location, the locations of BL62 and KI6 are just below the lateral and medial malleolus. But in some medical classics, the locations of BL62 and KI6 are between the bones and muscles below the malleolus. In the locations between the bones and muscles below the malleolus, it is possible to stimulate acupuncture on BL62 and KI6 by penetrating acupuncture because there is no bone structure. Conclusions : 1. By the 'half-up' position with the thumb upward, it is possible to stimulate vertically acupuncture on LU7 by 0.8 chon. 2. By the locations of BL62 and KI6 between the bones and muscles below the malleolus, it is possible to stimulate on BL62 and KI6 by penetrating acupuncture.

• 한국결정성장학회지
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• 제25권3호
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• pp.121-126
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• 2015

A novel $Ce^{3+}$ doped $Lu_3MgAl_3SiO_{12}$ phosphor ($Lu_{2.94}Ce_{0.06}MgAl_3SiO_{12}$) was successfully synthesized by a conventional solid-state reaction at $1450^{\circ}C$ for 5 h. The crystal structure of the synthesized phosphor powder was characterized by X-ray diffraction and Rietveld refinement. The prepared phosphor powder showed a broad peak at 550 nm, and the temperature dependence on photoluminescence properties of the prepared $Lu_{2.94}Ce_{0.06}MgAl_3SiO_{12}$ phosphor was investigated from 300 to 525 K. The activation energy for thermal quenching was determined by Arrhenius fitting. The experimental results clearly indicate that prepared $Lu_{2.94}Ce_{0.06}MgAl_3SiO_{12}$ phosphor has great potential for a down-conversion yellow phosphor in white light-emitting diodes.