• Journal of the Korea Academia-Industrial cooperation Society
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• v.21 no.2
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• pp.167-174
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• 2020

The purpose of this study was to investigate the kinematic comparison between successful and failed trials of Lopez vault techniques in male gymnastics. The subject, an Olympic gold medalist, was YHS (age: 27 years, height: 1.6 m, and mass: 53 kg) and fourteen high speed motion capturing cameras were used for data collection. The 26 reflective sensors were attached on major anatomical positions and 15 segment-body model was used to calculate the kinematic variables. According to results, the contact duration of the spring-board for successful trial(ST) was longer and that of failed trial(FT) and the range of motion of knee joint for ST was greater than that of FT. The movement times during pre-flight between ST and FT were same, but the movement time of horse contact period for ST was shorter than that of FT. The ST showed a longer movement time during post-flight and the longer horizontal distance than those of FT. Conclusively, YHS needs to approach the horse with a higher position of the body and higher incidence angle, as well as make faster twist angular velocity in an attempt to achieve ST.

• Proceedings of the Speleological Society Conference
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• 1995.09a
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• pp.39-44
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• 1995

$\bigcirc$ 동굴생물은 식물과 동물, 미생물로 크게 구분되지만 태양광선이 완전히 차단된 동굴내 환경에서는 동굴 동물들이 주종을 이루고 있다. $\bigcirc$ 동굴내의 동물에 관한 연구는 1966년 고씨동굴, 용담굴을 시발로 고수굴, 천동굴, 노동굴, 백룡글, 대이굴, 환선굴 등 강원도내에 분포하는 동굴 중 약 30% 정도는 동물을 포함한 생물상이 조사되었다. $\bigcirc$ 강원도의 동굴동물로서 확인된 것은 9강 30목 141종이며 강별로는 곤충강이 9목 50종 주형강이 4목 49종 갑각강이 6목 18종의 순으로 우세하고 목별로는 거미목이 15과 39종, 톡토기목이 7과 20종, 딱정벌레목이 8과 15종으로 우세한 편이다(남, 1987). $\bigcirc$ 동굴생물에 관한 연구는 육상생태계와 격리된 환경에서 생리, 생태적 적응을 통한 종의 분화나 유전, 진화문제를 추구하며 지하생태계와 육상생태계의 생물적인 유연관계 규명에 중요한 분야로 인정되며 아울러 독특한 특성을 지닌 동굴생물의 생존을 위한 방안과 노력이 일부동굴의 개방 및 개발에 앞서 더욱 구체적으로 모색되고 증대되어야 한다. $\bigcirc$ 동굴환경의 주요 특성은 첫째 햇빛에 차단되어 암흑상태이며, 둘째 내부습도가 높고 기온이나 수온의 년중변화가 심하지 않고, 셋째 먹이연쇄에 필수적인 영양공급원이 제한되어 있다. 따라서 광합성작용으로 성장하는 녹색식물은 태양광선이 유입되는 곳이나 인공조명시설 지역을 제외한 곳에서는 서식이 불가능하고 대형동물이나 초식동물은 생존이 어렵다. $\bigcirc$ 동굴내에는 환경에 적응하는 종들만이 서식할 수 있고 이들을 생태적 특성에 따라 세가지로 구분 할 수 있다. 환경적응 요인으로는 광도, 습도, 온도 영양공급원과 섭식장소, 수중생물의 경우는 특히 수온, 수량 영양원등이다.(중략). 본 연구의 접근방법으로는 ASRS의 개념적인 Reference Model을 수립하고 이 Reference Model에 대한 Formal Model로 DEVS(Discrete Event System Specification)을 이용하여 시스템을 Modeling하였다. 이의 Computer Simulation을 위하여 DEVS형식론 환경에서의 Simulation Language인 DEVSim ++ⓒ를 이용하여 시스템을 구현하였다.. 실형 결과로는 먼저 선형 상미분방정식의 예로 mass-damper-spring system, 비선형 상미분방정식의 예로는 van der Pol 방정식, 연립 상미분방정식의 예로는 mixing tank problem 등을 보였으며, 그의 공학에서 일어나는 여러 가지 문제들도 다루었다.화물에 대한 방어력이 증가되어 나타난 결과로 여겨지며, 또한 혈청중의 ALT, ALP 및 LDH활성을 유의성있게 감소시키므로서 감잎 phenolic compounds가 에탄올에 의한 간세포 손상에 대한 해독 및 보호작용이 있는 것으로 사료된다.반적으로 홍삼 제조시 내공의 발생은 제조공정에서 나타나는 경우가 많으며, 내백의 경우는 홍삼으로 가공되면서 발생하는 경우가 있고, 인삼이 성장될 때 부분적인 영양상태의 불충분이나 기후 등에 따른 영향을 받을 수 있기 때문에 앞으로 이에 대한 많은 연구가 이루어져야할 것으로 판단된다.태에도 불구하고 [-wh]의미의 겹의문사는 병렬적 관계의 합성어가 아니라 내부구조를 지니지 않은 단순한 단어(minimal $X^{0}$ elements)로 가정한다. 즉, [+wh] 의미의 겹의문사는 동일한 구성요 소를 지닌 병렬적 합성어([$[W1]_{XO-}$ $[W1]_{XO}$ ]$_{XO}$)로 그리고 [-wh] 의미의 겹의문사는 중복된 발은을 지닌 한 단어로 ([W]$_{XO}$

• Journal of Environmental Health Sciences
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• v.37 no.1
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• pp.29-43
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• 2011

The seasonal characteristics of atmospheric particulate matter (PM) were evaluated through the measurement of $PM_{10}$ (particles with an aerodynamic diameter of less than 10 ${\mu}m$) and $PM_{2.5}$ (particles with an aerodynamic diameter of less than 2.5 ${\mu}m$) collected in the downtown area of Iksan city over roughly two weeks in each season of 2004. During the sampling period, 54 samples of $PM_{10}$ and $PM_{2.5}$ were collected and then measured for mass concentrations of PM and its water-soluble inorganic ion species. The concentrations of $PM_{10}$ and $PM_{2.5}$ were highly variable on a daily time scale in all seasons, especially in fall. Annual concentrations of $PM_{10}$ and $PM_{2.5}$ were $54.7{\pm}21.6\;{\mu}g/m^3$ and $34.0{\pm}13.4\;{\mu}g/m^3$, respectively. The daily concentrations of the analyzed ions similarly showed a pronounced variation, although a difference between seasons existed. Among them, $SO_4^{2-}$, $NO_3^-$ and $NH_4^+$ were the most abundant ions in all seasons, contributing up to 32% of $PM_{10}$ and 39% of $PM_{2.5}$. The contribution of $SO_4^{2-}$ and $NO_3^-$ showed a seasonal variation, as $SO_4^{2-}$ was the highest during spring and summer and $NO_3^-$ was the highest during fall and winter. Non-seasalt $SO_4^{2-}$ and $NO_3^-$ were found to exist mainly as neutralized chemical components of $(NH_4)_2SO_4$ and $NH_4NO_3$ due to the high concentration of $NH_4^+$ in PM samples, which were a major form of airborne PM in all seasons. Seasonal characteristics of $PM_{10}$ and $PM_{2.5}$ in Iksan were described in relation to the temporal variations of daily concentration of PM and its inorganic ion species including inter-particle reactions.

• Journal of Environmental Science International
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• v.27 no.4
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• pp.241-250
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• 2018

The objective of this study was to estimate air quality trends in the study area by surveying monthly and seasonal concentration trends. To do this, the mass concentration of $PM_{10}$ samples and the metals, ions, and total carbon in the $PM_{10}$ were analyzed. The mean concentration of $PM_{10}$ was $33.9{\mu}g/m^3$. The composition of $PM_{10}$ was 39.2% ionic species, 5.1% metallic species, and 26.6% carbonic species (EC and OC). Ionic species, especially sulfate, ammonium, and nitrate, were the most abundant in the $PM_{10}$ and had a high correlation coefficient with $PM_{10}$. Seasonal variation of $PM_{10}$ showed a similar pattern to those of ionic and metallic species. with high concentration during the winter and spring seasons. $PM_{10}$ showed high correlation with the ionic species $NO_3{^-}$ and $NH_4{^+}$. In addition, $NH_4{^+}$ was highly correlated with $SO{_4}^{2-}$ and $NO_3{^-}$. We obtained four factors through factor analysis and determined the pollution sources using the United States Environmental Protection Agency(U.S. EPA) pollution profile. The first factor accounted for 51.1% of $PM_{10}$ from complex sources, that is, soil, motor vehicles, and secondary particles: the second factor indicated marine sources; the third factor, industry-related sources; and the last factor, heating-related sources. However, the pollution profile used in this study may be somewhat different from the actual situation in Korea because it was from US EPA. Therefore, to more accurately estimate the pollutants present, it is necessary to create a pollution profile for Korea.

• Clinical and Experimental Pediatrics
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• v.45 no.8
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• pp.994-999
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• 2002

Purpose : There is a predilection for subacute necrotizing lymphadenitis(SNL) in young Asian women. Few pediatric cases have been reported. This study was performed to evaluate clinical features of children with SNL. Methods : We retrospectively analyzed clinical features of 23 cases of SNL under 15 years of age identified in Nowon Eulji Hospital from February 1995 to January 2002. Two cases were diagnosed by excisional biopsy and 21 cases by fine needle aspiration. Results : The ages ranged from 14 months to 14 years(mean $8.1{\pm}3.8$ years). The male to female ratio was 1 : 1.6. Ten cases(10/23) were diagnosed in 2000. The onset was more frequent in spring. The common presenting symptoms were neck mass(22/23), pain(12/20) and fever(8/18). Fever subsided within two weeks in seven out of eight and lymphadenopathy resolved within five months in 14 out of 15. The mean WBC count was $7,664{\pm}3,454/mm^3$. Elevated levels of ESR(10/ 12) and lactate dehydrogenase(5/6) and positive reaction for CRP(3/4) were frequent. Radiologically measured greatest diameter of the enlarged lymph nodes was less than 2 cm in 14 out of 15. One case occurred in a child with alopecia areata and one case with type 1 diabetes. Clinical outcomes were good in 23 cases. Conclusion : SNL should be considered in children with cervical lymphadenopathy regardless of fever or pain. SNL seems not rare in pediatric groups in Korea.

• Journal of Internet Computing and Services
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• v.15 no.1
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• pp.171-178
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• 2014

This paper presents dynamic modelling of a virtual object in augmented reality environments when external forces are applied to the object in real-time fashion. In order to simulate a natural behavior of the object we employ the theory of Newtonian physics to construct motion equation of the object according to the varying external forces applied to the AR object. In dynamic modelling process, the physical interaction is taken placed between the augmented object and the physical object such as a haptic input device and the external forces are transferred to the object. The intrinsic properties of the augmented object are either rigid or elastically deformable (non-rigid) model. In case of the rigid object, the dynamic motion of the object is simulated when the augmented object is collided with by the haptic stick by considering linear momentum or angular momentum. In the case of the non-rigid object, the physics-based simulation approach is adopted since the elastically deformable models respond in a natural way to the external or internal forces and constraints. Depending on the characteristics of force caused by a user through a haptic interface and model's intrinsic properties, the virtual elastic object in AR is deformed naturally. In the simulation, we exploit standard mass-spring damper differential equation so called Newton's second law of motion to model deformable objects. From the experiments, we can successfully visualize the behavior of a virtual objects in AR based on the theorem of physics when the haptic device interact with the rigid or non-rigid virtual object.

• International Journal of Industrial Entomology and Biomaterials
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• v.4 no.2
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• pp.93-100
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• 2002

Cocoon production, which is a representative of traditional sericulture shifted into silkworm powder production in the spring of 1995. This, infect, signifies the change from the dress-centered textile business to the bio-industry and the functional resource industry. One of the most outstanding shifting is utilization of silkworm larvae for anti-diabetic agent. In Asian countries including Korea, silkworm powder derived from the domestic silkworm (Bombyx mori L.) has long been favored for anti-diabetic agent, but its efficacy was not tested until last decade by modern scientific methods. In this article, we reviewed the major researches on the silkworm powder as a blood glucose-lowering substance. After the beginning test of the efficacy of silkworm powder by a cooperative research between Department of Sericulture and Entomlogy, NIAST, RDA and Kyung Hee University, substantial data have been accumulated so far, In a serial experiment to select best condition, the fifth instar larvae prepared by freeze dry method turned out to have the best blood glucose-lowering effect. In the pharmacological experiment to understand the mechanism of silkworm powder in small intestine, the silkworm powder turned out to inhibit the activity of ${\alpha}$-glucosidase, by competitively binding to $\alpha$-type disaccharides. The animal experiment showed that the extract of silkworm powder prevents a rapid increase of blood glucose level after meal and prevents hunger and law blood glucose level during empty stomach. In the experiment to isolate the major component of silkworm powder, which exerts blood glucose-lowering effect, 1-deoxynojirimy-cin (DNJ) was eventually mass-purified, and it turned out that DNJ isolated from silkworm powder was excellent in its blood glucose-lowering effect. In the experiment to understand the personal difference of the efficacy of the silkworm powder, clinical candidates were divided on the basis of the criterion of traditional Chinese medicine: Tae-Yang, Tae-Um, So-yang, and So-Um. The result showed that silkworm powder has a tendency to reduce blood glucose level at fasting and at 2 hours after meal, and this trend was somewhat obvious in the Tae-Um body type. In summary, we reviewed scientific papers on the efficacy of silkworm powder and its purified DNJ as a blood glucose-lowering agent. These suggest that silkworm powder truly possesses blood glucose-lowering effect as documented in the traditional Chinese medicine, although further researches will be required to develop them as "medical" resource instead of functional food.

• Journal of Korean Society of Forest Science
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• v.98 no.2
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• pp.183-188
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• 2009

It is necessary to determine the amount of carbon dioxide ($CO_2$) absorbed by plants and released from forest floor into atmosphere, to gain a better understanding how forests participate in the global carbon cycle. Soil $CO_2$ efflux, litter production, and decomposition were investigated in Q. variabilis and P. densiflora stands in the vicinity of Gwangju, Chonnam province. Soil $CO_2$ efflux was measured using Infrared Gas Analyzer (IRGA) at midday of the 10th day at every month over 12-month period, to quantify seasonal and annual budgets of soil $CO_2$ efflux. Soil temperature and soil moisture were measured at the same time. Seasonal soil $CO_2$ efflux in Q. variabilis and P. densiflora were the highest in summer season. In August, maximum soil $CO_2$ efflux in Q. variabilis and P. densiflora was 7.49, $4.61CO_2{\mu}mol{\cdot}m^{-2}{\cdot}s^{-1}$, respectively. Annual $CO_2$ efflux in each stand was 1.77, $1.67CO_2kg{\cdot}m^{-2}$ respectively. Soil $CO_2$ efflux increased exponentially with soil temperature and related strongly in Q. variabilis ($r^2$=0.96), and in P. densiflora ($r^2$=0.91). Litter production continued throughout the year, but showed a peak on November and December. Annual litter production in the Q. variabilis and P. densiflora stands were $613.7gdw{\cdot}m^{-2}{\cdot}yr^{-1}$ and $550.5gdw{\cdot}m^{-2}{\cdot}yr^{-1}$.$yr^{-1}$, respectively. After 1 year, % remaining mass of Q. variabilis and P. densiflora litter was 48.2, 57.1%, respectively. The soil $CO_2$ efflux rates in this study showed clear seasonal variations. In addition, the temporal variation in the $CO_2$ efflux rates was closely related to the soil temperature fluctuation rather than to variations in the soil moisture content. The range of fluctuation of soil $CO_2$ efflux and litter decomposition rate showed similar seasonal changes. The range of fluctuation of soil $CO_2$ efflux and litter decomposition rate was higher during summer and autumn than spring and winter.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.40 no.8
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• pp.711-719
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• 2016

In this study, we derived an theoretical equation, using a simplified spring-mass model for the rolling stock, to obtain the overriding behavior of a leading vehicle, which is considered as the main factor in train accidents. To verify the derived equation, we created a simple 2D model based on the theoretical model, and a simple 3D model considering the characteristics of the power bogie. We then compared the theoretical results with the simulation results obtained using LS-DYNA. The maximum relative derivations in the vertical displacements at the first end-buffer, which is the most important point in overriding, were 3.5 [%] and 1.7 [%] between the two results. Further, we evaluated collision-induced overriding displacements using the theoretical equation for a rubber draft gear, a hydraulic buffer under various collision conditions. We have suggested a theoretical approach for the realization of overriding collision accidents or the energy absorption design of the front end of trains.

• Journal of Korean Society for Atmospheric Environment
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• v.22 no.4
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• pp.487-498
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• 2006

Total 438 precipitation samples were collected in Jeju City between 1997 and 2005, and their major ionic components were analyzed. The comparison tests using ion balance, electric conductivity and acid fraction were performed. It was found their correlation coefficients were in the range of 0.977$\sim$0.994, indicating the good quality of collected dam. The volume-weighted mean pH and electric conductivity were 4.8 and 23.0 $\mu$S/cm, respectively. with the ionic strength of 0.23$\pm$0.20 mM. The marine ($Na^+$, $Mg^{2+}$, and $CI^-$), anthropogenic (nss$SO_4{2-}$, $NO_3^-$, and $NH_4^+$) and soil (nss-$Ca^{2+}$) species have contributed to the ionic components of precipitation samples with 43$\sim$74%, 16$\sim$37% and $\sim$5%, respectively. The seasonal variations of $NO_3^-$ and nss-$SO_4^{2-}$ showed a distinct seasonality with higher concentrations in winter than summer, indicating an increase of fossil fuel consumption and a possibility of long-range transport of those pollutants from continental area along the dominant winter westerly. The levels of nss-$Ca^{2+}$ also were appeared the highest in winter and increased comparatively in spring season. possibly due to the soil influences including the Asian Dust. The acidification contribution of nss-$SO_4^{2-}$ and $NO_3^-$ showed 88$\sim$96%, and the free acidity was in the range of 6.0$\sim$40.1%. Interestingly, the backward trajectories for the case of upper 10% nss-$SO_4^{2-}$ and $NO_3^-$ levels have passed through the China continent before their arrival to Jeju. The precipitation of pH below 4.5 has been occurred frequently when the trajectory's path lied over the China continents. On the other hand, the air masses from the North Pacific area were characterized by lower 10% of nss-$SO_4^{2-}$- and $NO_3^-$ concentration, which demonstrated that air mass from the North Pacific was the cleanest among air masses moved to Jeju.