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李韓娥(Hana Lee),김정태(Jeongtae Kim) 대한전기학회 2008 전기학회논문지 Vol.57 No.4
We present a novel joint barcode deblurring and nonuniform illumination compensation algorithm for barcode signals whose number of modules is known. The proposed algorithm is based on a penalized least squares method using a roughness penalty function for an illumination model and a double well penalty function for a barcode signal model. In simulations, the proposed method shows an improved performance compared with a conventional method without compensating nonuniform illumination effects. In addition, the proposed method converges quickly during optimization (within 15 iterations), thereby showing strong possibility for real time decoding of barcode signals.
李韓娥(Hana Lee),金廷泰(Jeongtae Kim) 대한전기학회 2007 전기학회논문지 Vol.56 No.10
Existing barcode signal restoration algorithms are not robust to unmodeled outliers that may exist in scanned barcode images due to scratches, dirts, etc. In this paper, we describe a robust barcode signal restoration algorithm that uses the hybrid L₁-L₂ norm as a similarity measure. To optimze the similarity measure, we propose a modified iterative reweighted least squares algorithm based on the one step minimization of a quadratic surrogate function. In the simulations and experiments with barcode images, the proposed method showed better robustness than the conventional MSE based method. In addition, the proposed method converged quickly during optimization process.
Wnt/β-catenin 신호 활성화를 통한 미세전류 자극의 지방생성 억제 효과
황동현,이한아,이민주,조승관,김한성,Hwang, Donghyun,Lee, Hana,Lee, Minjoo,Cho, Seungkwan,Kim, Han Sung 대한의용생체공학회 2020 의공학회지 Vol.41 No.6
This study aimed to evaluate the inhibitory effect of micro-current stimulation(MCS) on adipogenesis regarding with Wnt/β-catenin pathway using the ob/ob mouse and 3T3-L1 cell line. 6-week old ob/ob male mice were equally assigned to four groups: obese group(ob), obese with MCS groups(50 μA, 200 μA, and 400 μA). 6-week old C57BL/6J male mice were assigned to the control group(CON). We analyzed abdominal adipose tissue volume by using in vivo micro-CT and measured the body weight, feed intake, liver weight and triglycerides in serum. All the MCS groups showed that significantly reduced body weight and triglycerides in serum. In the case of liver weight and abdominal adipose tissue volume, the inhibitory effect of adipogenesis was shown in the 200 μA and 400 μA groups. To elucidate the anti-obesity effect of MCS, β-catenin, C/EBPα and FAS protein expressions were analyzed by western blotting. β-catenin expression was upregulated, C/EBPα and FAS expression were down-regulated in the relatively high-intensity groups(200 μA and 400 μA). Thus, the 200 μA and 400 μA for the intensity of MCS were chosen for cell experiments. In the 3T3-L1 cell line, Wnt/β-catenin pathway including Wnt10b, Wnt3a, β-catenin and Cyclin D1 was activated in all MCS groups. Accordingly, the expression level of C/EBPα was decreased during the differentiation and lipid droplet was significantly reduced in Oil red O staining results. These results suggest that the Wnt/β-catenin signaling might be activated by MCS with current intensities between 200-400 μA and it may lead to anti-obesity effects.
좌골신경손상 쥐 모델을 이용한 미세전류 자극의 근위축 억제 효과 확인 및 자극 세기 별 비교
황동현,김서현,이한아,장승준,김세빈,김택중,최수임,곽호영,김한성,Hwang, Donghyun,Kim, Seohyun,Lee, Hana,Jang, Seungjun,Kim, Sebin,kim, Tackjoong,Choi, Sooim,Kwak, Hoyoung,Kim, Han Sung 대한의용생체공학회 2017 의공학회지 Vol.38 No.4
Microcurrent electrical stimulation(MES) has been used to accelerate recovery of atrophied skeletal muscle. However, convincing stimulation parameters for suppressing muscle atrophy due to injured sciatic nerve remains unclear. The objective of this study was to investigate the effective intensity of MES on restraining muscle atrophy with rat model underwent sciatic nerve injury(SNI). Twenty-5-week-old Sprague Dawley male rats were equally assigned to five groups : Control group(Control, CON, n = 4), Denervation group(Denervation, D, n = 4), Denervation with MES of $22{\mu}A$ group(Denervation + $22{\mu}A$, D+22, n = 4), Denervation with MES of $100{\mu}A$ group (Denervation + $100{\mu}A$, D+100 n = 4), Denervation with MES of $400{\mu}A$ group(Denervation + $400{\mu}A$, D+400, n = 4). To induce muscle atrophy, all rats in the D, D+22, D+100, and D+400 groups, were subjected to sciatic nerve injury on their right hindlimb and allowed to have 1 week of resting period. Following this period, rats underwent daily MES(60 min/ a day, 5times/1week) for 4 weeks. After that, we investigate morphological changes in muscle volume by using in vivo micro-computed tomography at week 0, 1, 3 and 5. After 5 weeks, the muscle volume had the highest value in D+400 group, and also noticeably increased in D+100 group compared to it in D group. The results of this study imply that MES with current intensities between $100-400{\mu}A$ can suppress muscle atrophy effectively.
고지방 식이 섭취 소동물 모델을 활용한 전신진동 자극의 복부 지방 감소 효능 평가
황동현,김서현,이한아,이상엽,서동현,조승관,천슬기,한태영,김한성,Hwang, Donghyun,Kim, Seohyun,Lee, Hana,lee, Sangyeob,Seo, Donghyun,Cho, Seungkwan,Chen, Seulgi,Han, Taeyoung,Kim, Han Sung 대한의용생체공학회 2017 의공학회지 Vol.38 No.1
The prevalence of obesity has noticeably increased worldwide over several decades with various complication. Even though anti-obesity drug treatments have been spotlighted by resulting in effective mean weight losses, its adverse effects cannot be overlooked. Thus, this study aimed to evaluate the effects of multi-frequency whole body vibration, one of the mechanical stimulus, as a countermeasure against obesity. Thirty-two-6-week-old C57BL/6J male mice were equally assigned to four groups: the Control group (CON, n = 8), the Sham group (Sham, n = 8), the sham with single frequency whole body vibration (S+V, n = 8), and the sham with multi frequency whole body vibration (S+MV, n = 8). After 4 weeks, morphologic changes in the adipose tissue were evaluated from three-dimensional images using in vivo micro-computed tomography. At 4 weeks, the volume of the abdominal adipose tissue, which had the highest value in Sham group, noticeably reduced in S+MV group compared to it in S+V group. These results implied that the accumulation of abdominal adipose tissue can be effectively reduced through applying multi-frequency whole body vibration.
황동현(Dong-Hyun Hwang),백영현(Young-Hyun Baek),김서현(Seo-Hyun Kim),이한아(Hana Lee),조승관(Seung-Kwan Cho),김한성(Han Sung Kim) 대한전자공학회 2019 대한전자공학회 학술대회 Vol.2019 No.11
Hair plays a number of roles in the human body, including protecting the head, keeping its appearance and maintaining the temperature of the head. With the recent development of a variety of non-invasive, rapid, cost-effective, and convenient approaches to hair loss, micro-current stimulation is expected to ultimately promote hair regeneration by promoting ATP synthesis in mitochondria, protein kinase activity, protein synthesis, cell division and maximizing the skin penetration effect of minoxidil through iontophoresis. Based on this, in this study, to compare the hair growth effect of microcurrent stimulation with minoxidil, a positive control group, seven-week-old male C57BL / 6 was divided into a control group (CON), minoxidil group (M), microcurrent stimulation group (MC), and minoxidil + microcurrent stimulation group (M + MC). The microcurrent stimulation applied to MC group and M + MC group was applied from 2 days after hair removal, and 50μA biphasic curruent was stimulated for 20 minutes 7 times a week for 2 weeks. Saline was applied to the CON group, and 5% minoxidil was applied to the M group at a predetermined amount (0.1 mL) at the site where hair was removed. As a result, hair growth increased after 6 days in the M + MC group, after 8 days in the MC group, and after 10 days in the M group. In addition, the MC and M + MC group was confirmed that the hair follicle is adjacent to the dermal layer and formed in a larger amount than the M group. From the results, it was found that the onset of hair growth progressed rapidly when microcurrent stimulation and minoxidil were applied together. This is thought to have both the hair growth effect of microcurrent stimulation itself and the penetration of minoxidil through iontophoresis.