• 한국기계가공학회지
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• 제5권3호
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• pp.17-22
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• 2006

Sunroof is getting widely used in automobiles since it maintains, compare to window, better air circulation as well as less noise while driving in high speed. In this study, we consider an electronic control type spoiler sunroof which slides backward after tilting a rear part of a glass. Installing a wind deflector on the sunroof reduces noise much more effectively. The height of the wind deflector is designed using a boundary theory related to incompressible air layer. The developed wind deflector is investigated experimentally by measuring a wind noise. When the height of the wind deflector is designed by a fixed type, the sunroof maintains a very quiet interior noise over a certain driving speed, nevertheless it produces relatively loud noise in low driving speed.

• International Journal of Naval Architecture and Ocean Engineering
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• 제9권2호
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• pp.177-184
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• 2017

The Coanda effect is the phenomenon of a fluid jet to stay attached to a curved surface; when a jet stream is applied tangentially to a convex surface, lift force is generated by increase in the circulation. The Coanda effect has great potential to be applied practically applied to marine hydrodynamics where various lifting surfaces are being widely used to control the behavior of ships and offshore structures. In the present study, Numerical simulations and corresponding experiments were performed to ascertain the applicability of the Coanda effect to a horn-type rudder. It was found that the Coanda jet increases the lift coefficient of the rudder by as much as 52% at a jet momentum coefficient of 0.1 and rudder angle of $10^{\circ}$.

• 대한예방한의학회지
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• 제6권2호
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• pp.86-94
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• 2002

Ligusticum Chuanxiong and its components were reviewed in terms of pharmacodynamic mechanisms. Three components of about 40 chemical components in Chuanxiong tetramethylpyrazine, ferulinolol and Butylidenephthalide have mainly been studied for its pharmacodynamic mechanisms which are focused on the increase in blood flow and anti-oxidative stress. The mechanisms for the effects of Chuanxiong on the increase in blood flow can be summarized as four ways, 1) anti-coagulation 2) blocker of ${\beta}1$ adrenergic receptor 3) cellular control of Ca++ level 4) collagen synthesis. Chuanxiong also showed the effectiveness on free radical-induced injury. It seems that its effectiveness is also related to the mechanisms for the increase in blood flow.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2016년도 추계학술대회 논문집
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• pp.204-205
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• 2016

Human power is not dependent on other energy sources, but rather is a source of power for ourselves. Human power, the cleanest energy in the world, can be our future. Therefore, we should be interested in sustainable alternative energy. This paper solves the uneven power generation by utilizing the energy storage capability of the flywheel. Therefore, it improved the efficiency by 5% compared to the existing generation method. DC generators produce power at variable speed operation. The constant voltage was generated from the DC-DC converter to the duty ratio control. Therefore, the charging efficiency is improved by 5% by the constant voltage charging of the battery. And it can suppress the decrease of the output due to the circulation current due to the deviation of the output voltage in parallel operation of the pedal generator.

• 한국정보처리학회:학술대회논문집
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• 한국정보처리학회 2000년도 제13회 춘계학술대회 및 임시총회 학술발표 논문집
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• pp.423-427
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• 2000

현재의 전자상거래는 일부의 예외들을 제외하고는 하드웨어가 전자상거래의 주요 대상이 되고 있으며 따라서 가장 중요한 수익성의 결정 요소인 효율적인 물류 처리를 위해 많은 노력을 하고있다. 하드웨어의 물류 이동을 수반하지 않는 디지털 상품은 매우 좋은 전자 상거래 대상이 될 수 있으나 오히려 불법 복제 문제 때문에 아직은 전자상거래의 기피 대상이 되고 있다. 전자상거래의 기반 기술인 공개키 암호화 기술의 정착은 디지털 상품의 온라인 유통에도 전혀 새로운 환경을 제공하고 디지털 상품의 유통에 있어 가장 커다란 문제인 사용권 관리 기술에도 커다란 기술적 진전을 가져오게 되어 일반적인 상식과는 달리 사용권관리, 불법 복제 방지는 이제 쉽게 해결될 수 있는 문제가 되었다. 이 논문은 온라인 유통에 적용될 수 있는 디지털 상품들의 특징을 설명하고 이들의 온라인 유통에 효율적으로 적용될 수 있는 동적 사용권 관리 기술에 대해 논의하였다. 이 사용권 관리 기술은 이미 실제 유통 시스템에 잘 적용되고 있어 실례를 통해 그 의미를 살펴보았다.

• International journal of advanced smart convergence
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• 제9권4호
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• pp.203-208
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• 2020

In this paper, we propose the design and implementation of a desktop LED stand and smart app that automatically adjusts color temperature and illuminance for optimal brightness and eye health by improving the structural problem of the LED stand. It is a tabletop LED stand that supports optimal brightness through color temperature control and heat transfer through infrared LED to relieve eye strain through blood circulation and muscle movement. The LED stand works with the smartphone to automatically adjust the optimal brightness and color temperature for the user's environment. In addition, the brightness of the infrared LED is adjusted to a living frequency of 4Hz to relax the eye muscles and reduce eye strain. This study implemented an effective measured data-based system of previous studies through the color temperature and illumination of LED lighting, and near-infrared rays, and presented meaningful results by conducting an experiment to prove the effect through subjects.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2020년도 가을 학술논문 발표대회
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• pp.4-5
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• 2020

Pipe support is a representative structure that supports slab formwork, and it is a representative temporary equipment that has been systematically managed since the 1990s when the domestic temporary equipment performance test system was introduced. Nevertheless, it is also a reality that many of the products in circulation are used products that are reused and do not meet the performance of the initial manufacturing stage. However, if only new products are insisted, it could lead to delays in the process due to an increase in construction costs and difficulties in timely delivery. On the contrary, it is not acceptable for the safety of the construction site to use products of low quality without verification procedures or standards. Therefore, this study attempts to grasp the management system such as safety certification for temporary equipment and the actual condition of quality control to maintain performance, and propose improvement plans.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2020년도 전력전자학술대회
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• pp.251-252
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• 2020

화석연료 사용으로 발생하는 환경문제 대처방안으로 풍력 등 신재생 에너지원 사용의 필요성이 강조되고 있으며, 이러한 사회적 요구에 따라 신재생 에너지 발전 시스템의 대용량화 추세에 있다. 시스템 대용량화에 있어 안정적인 에너지 발전과 공급을 위해 전력변환장치의 신뢰성 향상이 필요하다. 특히, 풍력발전시스템의 경우 돌풍 등 일정하지 않은 풍속으로 인하여 전력변환장치의 잦은 고장이 발생하고, 이는 전체 시스템의 신뢰성 결정에 주된 영향을 미친다. 본 논문에서는 병렬형 전력변환장치에서 높은 고장률을 보이는 스위칭 소자의 열적 스트레스를 줄이기 위한 무효전력순환 기반 능동 열 제어기법을 제안한다. 제안한 기법의 동작특성을 이론적으로 분석하고, 열 회로망 시뮬레이션을 통해 그 영향을 검증한다.

• Korean Circulation Journal
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• 제54권5호
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• pp.223-232
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• 2024

Trigger and functional substrate are related to the tone of autonomic nervous system, and the role of the autonomic nerve is more significant in paroxysmal atrial fibrillation (AF) compared to non-paroxysmal AF. We have several options for neuromodulation to help to manage patients with AF. Neuromodulation targets can be divided into efferent and afferent pathways. On the efferent side, block would be an intuitive approach. However, permanent block is hard to achieve due to completeness of the procedure and reinnervation issues. Temporary block such as botulinum toxin injection into ganglionated plexi would be a possible option for post-cardiac surgery AF. Low-level subthreshold stimulation could also prevent AF, but the invasiveness of the procedure is the barrier for the general use. On the afferent side, block is also an option. Various renal denervation approaches are currently under investigation. Auditory vagus nerve stimulation is one of the representative low-level afferent stimulation methods. This technique is noninvasive and easy to apply, so it has the potential to be widely utilized if its efficacy is confirmed.

• Korean Circulation Journal
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• 제52권10호
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• pp.721-736
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• 2022

Aortic stenosis (AS) is one of the most common valvular heart diseases and the number of patients with AS is expected to increase globally as the older population is growing fast. Since the majority of patients are elderly, AS is no longer a simple valvular heart disease of left ventricular outflow obstruction but is accompanied by other cardiac and comorbid conditions. Because of the significant variations of the disease, identifying patients at high risk and even earlier detection of patients with AS before developing symptomatic severe AS is becoming increasingly important. With the proven of efficacy and safety of transcatheter aortic valve replacement (TAVR) in the severe AS population, there is a growing interest in applying TAVR in those with less than severe AS. A medical therapy to reduce or prevent the progression in AS is actively investigated by several randomized control trials. In this review, we will summarize the most recent findings in AS and discuss potential future management strategies of patients with AS.