• 한국운동역학회지
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• 제12권2호
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• pp.393-405
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• 2002

When our body is immersed in water, we experience weightlessness. The degree of weightlessness that we experience varies depending on the proportion of the body immersed in water, being governed by the relationship between the weight of body and the buoyant force acting on the body. Human body during the performance of swimming in no exception to these influences. Swimmers body is subject to a time and position dependent force system. Even the magnitude of the buoyant force acting on the swimmers body at every given instant and the corresponding position of the CB change continuously. The findings of this study support the following conclusions. The buoyancy torque was the primary source of bodyroll exhibited by front crawl swimmers performing at distance pace, accounting for 88 % of the bodyroll. Faster swimmers used buoyancy more effectively to generate bodyroll, partially supporting the postulation that an effective use of buoyancy for bodyroll may reduce the generated hydrodynamic forces to be wasted in non-propulsive directions and maximize forward propulsion.

• 한국초등과학교육학회지:초등과학교육
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• 제28권1호
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• pp.24-34
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• 2009

The purpose of this study is to examine the effects of background knowledge on problem solving. To achieve this aim, I proposed the model which shows problem solving process centering around background knowledge, conducted the lessons concerning the concept 'weightlessness' on pre-service elementary teachers, and then classified the pre-service elementary teachers into several groups by the difference of the results presented in the process of solving the problems on weightlessness. And I examined qualitatively the effects of background knowledge on problem solving through the interview with 11 volunteers. On the cause of the failing the problem solving, the failure of acquiring or activating the background knowledge related to the learning concept was most frequently, secondly the use of the background knowledge unrelated to the learning concept, and thirdly the failure of understanding the teaming concept. To acquire or activate the background knowledge related to the teaming concept was more difficult than to understand the new teaming concept, and the cases that use the background knowledge unrelated to the learning concept failed to solve problem. The result of interview, all interviewee understood the learning concept correctly, but all of them who fail to acquire or activate the background knowledge related to the learning concept, or use the background knowledge unrelated to the learning concept, could not solve the problem.

• 한국초등과학교육학회지:초등과학교육
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• 제24권1호
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• pp.43-50
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• 2005

This study examined the effects of the result of ascertaining predictions on cognitive conflict and conceptual change when students teamed the concept of weightlessness. Participants were 200 pre-service elementary teachers. They answered the pretest composed of two items. Through the demonstration on either of two items of the pretest, they identified whether their predictions were correct or not. In addition, students' cognitive conflicts were measured. After brief instructional treatment, the posttest was conducted. The results of this study are as follows: The more students who identified their own predictions on the experiment were incorrect there were, the more effective it was on cognitive conflict and conceptual change. And cognitive conflicts and conceptual changes of students who identified that their predictions were incorrect were generated meaningfully more than those of students who identified that their predictions were correct. From these results, it is concluded that students who identified that their predictions were correct experience cognitive conflicts, but their cognitive conflicts and conceptual changes were smaller than those of students who identified that their predictions were incorrect.

• The Korean Journal of Physiology
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• 제24권1호
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• pp.51-65
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• 1990

The purpose of the present study was to examine the hemodynamic responses, especially in arterial and skin blood flows, in conjunction with the changes of plasma catecholamine levels as an indirect marker of adrenergic tone during the early stage of head-down tilt (HDT), and to evaluate the early physiological regulatory mechanism in simulated weightlessness. Ten mongrel dogs, weighing8\;{\sim}\;14\;kg, were intravenously anesthetized with nembutal, and postural changes were performed by using the tilting table. The postural changes were performed in the following order: supine, prone, HDT $(-6^{\circ}C)$ and lastly recovery prone position. The duration of each position was 30 minutes. The measurements were made before, during and after each postural change. The arterial blood flow $({\.{Q}})$ at the left common carotid and right brachial arteries was measured by the electromagnetic flowmeter. Blood pressure (BP) was directly measured by pressure transducer in the left brachial artery. To evaluate the peripheral blood flow, skin blood flow $({\.{Q}})$ was calculated by the percent changes of photoelectric pulse amplitude on the forepaw, and skin temperature was recorded. The peripheral vascular resistance (PR) was calculated by dividing respective mean BP values by ${\.{Q}}$ of both sides of common carotid and brachial arteries. Heart rate (HR), respiratory rate (f) and PH, $Po_{2},\;Pco_{2}$ and hematocrit of arterial and venous blood were also measured. The concentration of plasma epinephrine and norepinephrine was measured by radioenzymatic method. The results are summarized as follows: Tilting to head-down position from prone position, HR was initially increased (p<0.05) and BP was not significantly changed. While ${\.{Q}}$ of the common carotid artery was decreased (p<0.05) and PR through the head was increased, ${\.{Q}}$ of the brachial artery was increased (p<0.05) and PR through forelimbs was decreased. ${\.{Q}}$ of the forepaw was initially increased (p<0.05) and then slightly decreased, on the whole revealing an increasing trend. Plasma norepinephrine was slightly decreased and the epinephrine was slightly increased. f was increased and arterial pH was increased (p<0.05). In conclusion, the central blood pooling during HDT shows an increased HR via Bainbridge reflex and an increased ${\.{Q}}$ of the forepaw and brachial ${\.{Q}}$, due to decreased PR which may be originated from the depressor reflex of cardiopulmonary baroreceptors. It is suggested that the blood flow to the brain was adequately regulated throughout HDT $(-6^{\circ}C)$ in spite of central blood pooling. And it is apparent that the changes of plasma norepinephrine level are inversely proportional to those of ${\.{Q}}$ of the forepaw, and the changes of epinephrine level are paralleled with those of the brachial ${\.{Q}}$.

• 한국디지털건축인테리어학회논문집
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• 제12권4호
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• pp.97-105
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• 2012

This study aims to evaluate Rietveld's creative design style and concepts. To this end, I looked into the evaluation of major researchers on Rietveld, classified all his works into four groups according to the design types and analyzed them. As follows: based on the results of the analysis of works I concluded. First, Rietveld created the concept of the spatial extension to the ingenious joint which had the structural node formed of three listels with quadrangular section. It is the design innovation that led to liberate the closed construction. Second, Rietveld had opened up the possibility to neutralize the gravitational three-dimensional works. He subtracted the weight in the direction of gravity from the three-dimensional structure of the works and painted the three primary colors on them partially to get rid of the original material color. Therefore they looked like the forms liberated from gravity. Third, Rietveld ripped off the surfaces of cube through several formative experiments and decomposed the volume into the tesseract. Through this method of realizing the new plastic concepts, he completed the architectural models of weightlessness. Fourth, Rietveld opened the possibility of the realization of the three-dimensional works integrated all space and time in the one-pieced works and the folded works. Fifth, Rietveld steadily experimented and realized the internal and external integration of time and space in his later works.

• International Journal of Internet, Broadcasting and Communication
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• 제15권3호
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• pp.82-87
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• 2023

<Deep Sea> is an 3D animated film that stands out for its exceptional special effects and distinctive artistic style. The film employs a multitude of dazzling and vibrant ink particles, creating a strong sense of three-dimensionality and weightlessness, while simultaneously portraying a dreamlike and elegant representation of a deep sea ink painting. Furthermore, through the utilization of fragmented stream of consciousness narrative technique, the film establishes a unique artistic effect infused with a Chinese atmosphere. This paper by analyzing the unique particle ink art style and color and stream of consciousness narrative methods in film, this paper discusses the innovative art style generated by traditional ink art style combined with three-dimensional technology, and the integration of traditional ink art ideas and artistic conception in animated films. The objective is to cultivate a new ink art style and prove the importance of traditional cultural expression in animated films, while providing new perspectives for the future application of traditional art in animation.

• Journal of Korean Medical Science
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• 제33권48호
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• pp.316.1-316.10
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• 2018

Background: Water pressure and muscle contraction may influence bone mineral density (BMD) in a positive way. However, divers experience weightlessness, which has a negative effect on BMD. The present study investigated BMD difference in normal controls and woman free-divers with vertebral fracture and with no fracture. Methods: Between January 2010 and December 2014, traditional woman divers (known as Haenyeo in Korean), and non-diving women were investigated. The study population was divided into osteoporotic vertebral fracture and non-fracture groups. The BMD of the lumbar spine and femoral neck was measured. The radiological parameters for global spinal sagittal balance were measured. Results: Thirty free-diving women and thirty-three non-diving women were enrolled in this study. The mean age of the divers was $72.1{\pm}4.7$ years and that of the controls was $72.7{\pm}4.0$ years (P = 0.61). There was no statistical difference in BMD between the divers and controls. In divers, cervical lordosis and pelvic tilt were significantly increased in the fracture subgroup compared to the non-fracture subgroup (P = 0.028 and P = 0.008, respectively). Sagittal vertical axis was statistically significantly correlated with cervical lordosis (Spearman's rho R = 0.41, P = 0.03), and pelvic tilt (Spearman's rho R = 0.46, P = 0.01) in divers. Conclusion: BMD did not differ significantly between divers and controls during their postmenopausal period. When osteoporotic spinal fractures develop, compensation mechanisms, such as increased cervical lordosis and pelvic tilt, was more evident in traditional woman divers. This may be due to the superior back muscle strength and spinal mobility of this group of women.

• 한국항행학회논문지
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• 제24권6호
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• pp.485-490
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• 2020

최근 국내 조선 산업과 IT융합기술에 대한 연구가 활발한 가운데 선박 안전운항을 위한 위성탐지 기술 발달로 선박에서는 장거리 식별추적 장치 및 자동식별 장치의 의무화로 선박이동 상황을 모니터링 할 수 있어 안전항해에 도움을 주고 있으나, 무중항해 시 시정 상태를 레이다에 의존하는 항해사에게 위험을 경보해 줄 수 있는 안전장치 개발이 필요하다. 이에 광센서를 이용하여 감지하고 알려주는 해무 감지 경보 시스템을 개발하였다. 제작된 해무 감지 경보 시스템은 소형, 저 전력의 광센서 송수신기와 센싱 데이터 처리 모듈로 구성되었다. 시험을 통해 해무가 있는 경우와 없는 경우 각각에 대해 제작된 해무 경보 시스템은 해무 농도를 검출하는 것을 확인하였다. 또한 해무 농도에 따라 선박 엔진 RPM 조절이 가능하고, 결과적으로 선박의 안전 운항을 보조 장치로 활용 가능함을 확인하였다.

• 패션비즈니스
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• 제27권1호
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• pp.77-109
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• 2023

This study attempted to understand current status of overseas virtual fashion brands and analyze attributes of common digital fashion brands. Based on brand analysis criteria of previous studies, digital fashion brands were analyzed for brand concept, price range, characteristic elements, and attributes. Digital fashion design elements of items, colors, materials, patterns, and effects were analyzed by collecting images of brands' digital fashion design products. Digital fashion brands could be divided into experimental and creative digital fashion brands and digital fashion brands aiming for popular brands. This study introduces a creative fashion collection that experiments sustainability and future value. It shares a new way of self-expression and a playful culture centered on the younger generation. In terms of fashion design elements, fashion items were similar to the existing fashion category, but included other accessories that reflected the lifestyle of Generation Z. Silhouette expressed a minimalistic futuristic image centered on straight silhouettes. Color showed a bold and modern color image through black and color contrast. Unique patterns reflecting the concept of the brand appeared, centering on abstract and geometric patterns. Regarding materials and effects, new elements differentiated from existing fashion design area, showing meaningful characteristics. Digital materials are developed and proposed for sustainability. Materials (such as metal, glass, plastic) and effects (such as weightlessness, flames) expand impossible senses in reality and enable new fashion experiences. This is a case study of digital fashion brands. It is meaningful in that it identifies characteristics and discusses their values and meanings.

• The Korean Journal of Physiology
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• 제21권2호
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• pp.211-223
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• 1987

Head-down tilt (HDT) at $-6^{\circ}$ has been commonly used as the experimental model in both man and animals to induce the blood shift toward the head or central protion of the body, demonstrating similar physiological effect encountered in the weightlessness in the orbital flight. There are few reports about the physiological response upon the cardiovascular regulatory system or the tolerance to the $(-6^{\circ})$ HDT within a relatively short period less than 1 hour. Therefore, the purpose of this study way to observe the effects of $-6^{\circ}$ HDT on cardiovascular system within 30 minutes and to evaluate early regulatory mechanism for simulated hypogravity. Ten mongrel dogs weighing 8-12 kg were anesthetized with the infusion of 1% ${\alpha}-chloralose$ (100 mg/kg) intravenously, and the postural changes were performed from the supine to the $-6^{\circ}$ head-down Position, then from the head-down to the supine (SUP), and each posture was maintained for 30 minutes. Blood flow $({\dot{Q}})$ through common carotid and femoral arteries were determined by the electromagnetic flowmeter. Mean arterial pressure (MAP), heart rate (HR), respiratory rate , and pH, $P_{O_2}$, $P_{CO_2}$ and hematocrit (Hct) of arterial and venous blood were also measured. The peripheral vascular resistance was calculated by dividing respective MAP values by ${\dot{Q}}$ through both sides of common carotid or femoral arteries. The concentration of plasma epinephrine and norepinephrine was determined by Peuler & Johnson's radioenzymatic method. The results are summarized as follows: In the initial 5 minutes in $-6^{\circ}$ HDT, HR was significantly (p<0.05) increased and MAP slightly decreased. Although ${\dot{Q}}$ and carotid peripheral artery resistance were not significantly changed, ${\dot{Q}}$ through femoral artery was diminished and femoral peripheral artery resistance was elevated. In the SUP, the initial changes of MAP and HR were increased (p<0.05), but those of ${\dot{Q}}$ and peripheral vascular resistance through both common carotid and femoral arteries were not significant. After 10 minutes of each postural change in both HDT and SUP, MAP was maintained almost equal to that of the level of pretilting control. During 60 minutes of both postural changes of HDT and SUP, $P_{O_2}$ and Hct were not changed significantly. However pH tended to increase slowly and $P_{CO_2}$ was gradually decreased. The pH and $P_{CO_2}$ seemed to be related to the increased respiratory rate. Plasma epinephrine concentration was not changed significantly and plasma norepinephrine concentration was slightly decreased in the course of HDT and also at 10 minutes of SUP. However these concentration changes were statistically insignificant. From these results, it may be concluded that the effect of $-6^{\circ}$ HDT for 30 minutes on the cardiovascular system and plasma catecholamine levels of the dog is minimum and it is suggestive that the cardiovascular regulatory mechanism, possibly mediated by so called gravity receptors including baroreceptor and volume receptor, has been properly and adequately operated.