• 한국CDE학회논문집
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• 제19권2호
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• pp.111-118
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• 2014

In tangible augmented reality (AR) environments, the user interacts with virtual objects by manipulating their physical counterparts, but he or she often encounters awkward situations in which his or her hands are occluded by the augmented virtual objects, which causes great difficulty in figuring out hand positions, and reduces both immersion and ease of interaction. To solve the problem of such hand occlusion, skin color information has been usefully exploited. In this paper, we propose an approach to simple and effective construction of a skin color map which is suitable for hand segmentation and tangible AR interaction. The basic idea used herein is to obtain hand images used in a target AR environment by simple image subtraction and to represent their color information by a convex polygonal map in the YCbCr color space. We experimentally found that the convex polygonal map is more accurate in representing skin color than a conventional rectangular map. After implementing a solution for resolving hand occlusion using the proposed skin color map construction, we showed its usefulness by applying it to virtual design evaluation of digital handheld products in a tangible AR environment.

• 대한의생명과학회지
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• 제6권1호
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• pp.37-43
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• 2000

흰쥐에 있어서 피부의 공기차단이 피부조직의 xanthine oxidase (XO) 활성에 미치는 영향을 검토하고자 직경 46 mm, 높이 10 mm인 petri dish-shaped glass chamber에 순간접착제 ($\alpha$-cyanoacrylate)를 이용하여 실험동물의 등 부위 피부조직에 부착시켜 10일간 공기의 접촉을 차단하였다. 공기 접촉 차단 5일째에 피부의 땀 축적량은 약 400 mg 정도이었으나, 10일째에는 약 25 mg으로 감소하였다. 5일간 피부차단 시 피부조직 중 XO 활성은 대조군에 비해 증가하였으며, 그 증가율은 chamber 내의 땀 축적량과 관련하여 10일간 피부차단군 보다 높게 나타났다. 5일간 피부차단 시 XO의 기질 농도 변화에 따른 반응 속도를 관찰한 결과, 대조군에 비해 V$_{max}$ 치가 높게 나타났다. 이상 실험 결과를 보아, 피부의 공기접촉 차단으로 피부조직 중 XO효소 활성이 증가된 것은 이 효소 단백 합성 유도에 기인되며, 이는 피부조직에서 oxygen free radical의 생성을 유도하여 외부 환경에 대한 방어장벽작용에 관여할 것으로 생각된다.

• Journal of Pharmaceutical Investigation
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• 제40권6호
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• pp.373-378
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• 2010

In order to develop a topical preparation which has a high occlusive property with skin moisturization, nano-structured lipid carrier (NLC) systems along with solid lipid nanoparticle (SLN) were designed. Various NLC dispersions were successfully formulated with Compritol 888 ATO as a solid lipid, Labrafil M 1944 CS as an oil, and Tween 80 as a surfactant. The increase of oil content (5 to 50%) led to the decrease in the occlusion factor in the order of SLN > NLC-5 > NLC-15 = NLC-30 > NLC-50. Particle size of lipid particulates was in the range of 100 to 160 nm. NLC-based carbogels were prepared by the employment of humectants such as urea, glycerin, and Tinocare GL to carbomer gel. NLC-30 gel formulations containing 4 or 8 % of lipid particles showed improved occlusive effect in vitro, compared to NLC-free gel base. Even though NLC-free gel base revealed comparable occlusion effect by itself, the occlusion factor of 4 % NLC-30 gel was about 2-fold higher than that of NLC-free gel base.

• Physical Therapy Rehabilitation Science
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• 제2권2호
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• pp.63-69
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• 2013

Objective: To assess the effect of vitamin D administration on the skin blood flow response to occlusion and heat. Design: Cross-sectional study. Methods: Twenty age matched subjects; 10 who had diabetes and 10 who were controls were administered 4,000 IU of vitamin D3 for 3 weeks at breakfast. The function of the endothelial cells was evaluated in 2 ways; first, the response to 4 minutes of vascular occlusion of the skin was measured with a laser Doppler flow meter. Second, the skin blood flow response to local heat at 42 degrees C for 6 minutes was examined. Results: The results of the experiments showed that the blood flow response to heat was reduced after 3 weeks administration of vitamin D in the subjects with diabetes and in the control subjects (p<0.05). The response to occlusion was not significantly different within each group before and after vitamin D administration, but the group with diabetes had a significantly lower blood flow response to occlusion than did the controls (p<0.05). Conclusions: Acute doses of vitamin D may impair nitric oxide production and reduce blood flow to tissue during stressors in people with diabetes.

• Physical Therapy Rehabilitation Science
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• 제1권1호
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• pp.6-12
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• 2012

Objective: Coenzyme (CoQ10) is an enzymatic co factor used in normal cellular metabolism. Recent evidence shows that in people with heart disease it can reverse endothelial cell damage in the blood vessels. It is also a potent antioxidant. Design: One group pretest-posttest design. Methods: In the present study, endothelial function was evaluated using the response to occlusion and heat before and 2 weeks after administration of CoQ10, 300 mg/day. Thirty Eight subjects, who are physical therapy students, participated in a series of experiments to see if taking 300 mg of CoQ10 daily for 2 weeks would impact resting blood flow in the forearm skin and the blood flow response to 4 minutes of vascular occlusion and the response to local heat ($42^{\circ}C$) for 6 minutes. Results: The results showed that, for this population, there was no difference in the response to heat. However, the response to occlusion was improved after administration of CoQ10. Conclusions: It would appear that in a young population CoQ10 has no effect on the nitric oxide vasodilator pathway in skin but does influence other vasodilator pathways.

• Journal of Chest Surgery
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• 제33권10호
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• pp.792-797
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• 2000

Background : Even though there were developments in various treatment techniques for acute arterial occlusion this disease still has high rate of mortalities and limb amputations. We investigated the combined diseases symptoms location of occlusion type of treatment complication and prognosis in our patients. Meterial and methods: This study recruited 48 patients(42 men, 6 women, mean age 57.7 years) who received the operation from January 1995 toDecember 1998. We investigated the post-operation course via medical record review or telephone interview with patients or their family members. Result: The most common combined diseases were atherosclerosis in 30 patients. other diseases were 17 diabetes mellitus 16 hypertension and 12 atrial firillation. Pain and clod sensation were noticed in all patients paresthesia in 5 patients fibrillation. Pain and cold sensation were noticed in all patients paresthesia in 5 patients and lower extremity paralysis in 11 patients. In 29 patients the time interval from the onset of symptom to admission was over 72 hours and 15 patients were admitted within 24 hours. The distribution of arterial occlusion location was at 28 femoral arteries 14 popliteal arteries and 6 iliac arteries. All the patients were received embolectomy and 5 patients were received additional bypass grafting. Postoperative complications were 12 reocclusions. 6 compartment syndromes 6 skin necrosis and 2 acute renal failure. The mortality rate was 16.7%(8/48) and the amputation rate was 25% Conclusion : This study revealed 25% reocclusion 25% limb amputation and 16.7% mortaliyt. To improve the prognosis of acute lower extrements arterial occlusion early diagnosis and understand the underlying diseases prompt treatment and operation additional operation including interventional radiologic examination and thorough postoperative care would be appreciated.

• Journal of Korean Neurosurgical Society
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• 제48권2호
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• pp.105-108
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• 2010

Objective : Some neurosurgeons intentionally ligate the branches of the superficial temporal artery (STA) that are not used in standard STA-to-middle cerebral artery (MCA) anastomosis for the purpose of improving the flow rate in the bypass graft. We investigated changes in bypass flow during temporary occlusion of such unused branches of the STA. Methods : Bypass blood flow was measured by a quantitative microvascular ultrasonic flow probe before and after temporary occlusion of branches of the STA that were not used for anastomosis. We performed measurements on twelve subjects and statistically assessed changes in flow. We also examined all the patients with digital subtraction angiography in order to observe any post-operative changes in STA diameter. Results : Initial STA flow ranged from 15 mL/min to 85 mL/min, and the flow did not change significantly during occlusion as compared with preocclusion flow. The occlusion time was extended by 30 minutes in all cases, but this did not contribute to any significant flow change. Conclusion : The amount of bypass flow in the STA seems to be influenced not by donor vessel status but by recipient vessel demand. Ligation of the unused STA branch after completion of anastomosis does not contribute to improvement in bypass flow immediately after surgery, and furthermore, carries some risk of skin necrosis. It is better to leave the unused branch of the STA intact for use in secondary operation and to prevent donor vessel occlusion.

• 산업기술연구
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• 제28권B호
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• pp.143-148
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• 2008

A real-time face detection is to find human faces robustly under the cluttered background free from the effect of occlusion by other objects or various lightening conditions. We propose a face detection system for real-time applications using wavelet decomposition method based on Gabor features. Firstly, skin candidate regions are extracted from the given image by skin color filtering and projection method. Then Gabor-feature based template matching is performed to choose face cadidate from the skin candidate regions. The chosen face candidate region is transformed into 2-level wavelet decomposition images, from which feature vectors are extracted for classification. Based on the extracted feature vectors, the face candidate region is finally classified into either face or nonface class by the Levenberg-Marguardt back-propagation neural network.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제12권6호
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• pp.2826-2840
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• 2018

Traditional methods based active contours or region merging are powerless in processing images with blurring border or hair occlusion. In this paper, a structure based convolutional neural networks is proposed to solve segmentation of skin lesion image. The structure mainly consists of two networks which are segmentation net and discrimination net. The segmentation net is designed based U-net that used to generate the mask of lesion, while the discrimination net is designed with only convolutional layers that used to determine whether input image is from ground truth labels or generated images. Images were obtained from "Skin Lesion Analysis Toward Melanoma Detection" challenge which was hosted by ISBI 2016 conference. We achieved segmentation average accuracy of 0.97, dice coefficient of 0.94 and Jaccard index of 0.89 which outperform the other existed state-of-the-art segmentation networks, including winner of ISBI 2016 challenge for skin melanoma segmentation.

• 방송공학회논문지
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• 제21권6호
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• pp.861-877
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• 2016

본 논문에서는 실시간 얼굴 추적을 위하여 기존의 CamShift 알고리즘의 단점을 보완한 새로운 CamShift 알고리즘을 제안한다. 배경 내 추적 객체와 색상이 유사한 객체가 존재할 경우 기존 CamShift 알고리즘은 불안정한 추적을 보여준다. 이러한 문제점을 화소 단위로 거리정보를 획득할 수 있는 Kinect의 깊이 정보와 HSV 색공간 기반의 피부색 후보영역을 추출하는 Skin Detection 알고리즘을 이용하여 색상분포만 이용하는 기존의 CamShift의 단점을 보완한다. 또한 추적하던 객체가 사라지거나 가려짐이 발생할 경우에도 다시 추적할 수 있는 특징점 기반의 매칭 알고리즘을 통하여 차폐영역에 강인한 특성을 가지게 한다. 이러한 향상된 CamShift 알고리즘을 사람의 얼굴 추적에 적용함으로써 다양한 분야에 활용 가능한 강인한 얼굴추적 알고리즘을 제안하고자 한다. 실험결과 제안하는 알고리즘은 기존의 추적 알고리즘인 TLD보다 월등히 빠른 처리속도와 더 우수한 추적성능을 보여주었고, CamShift 보다 조금 느리지만 기존의 CamShift가 가지고 있는 문제점들을 해결하였다.