• Proceedings of the Korean Information Science Society Conference
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• 2003.04c
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• pp.618-620
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• 2003

본 논문에서는 Base를 향해 낙하하는 물체의 충돌 연상에 대해 모델링한다. 충돌 현상에 관한 연구는‘충돌 감지’, ‘충돌 반응 양상’라는 두 부분으로 나눌 수 있다. 현재까지의 많은 논문들은‘충돌 감지’에 중점을 두고 설계하였다. 따라서 본 논문은 이미 않은 연구 결과가 드러난 ‘충돌 감지’부분은 갖추어졌다고 가정하고,‘충돌 반응 양상’를 위주로 설계의 초점을 둘 것이다. 여기서 설계할 모델의 궁극적인 목적은 복잡한 실세계와 완벽하게 일치하도록 구현하는 것이 아니라, 사람이 보기에 자연스럽다고 느낄 수 있도록 하는 것에 초점을 두는 것이다. 이를 통해, 적은 연산량으로 몰입감있는 가상 환경을 구축할 수 있다.

• Proceedings of the Korean Vacuum Society Conference
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• 2014.02a
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• pp.217.1-217.1
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• 2014

반도체 및 디스플레이 산업은 많은 공정들에서 저온 플라즈마 반응을 이용한다. 특히 소자 제작을 위한 실리콘 박막의 증착은 저온 플라즈마 공정의 주요 공정이다. 하지만 실리콘 박막을 합성하는데 있어서 저온 플라즈마에서 형성되는 실리콘 나노 입자는, 오염입자로써 박막의 특성을 악화시켜 소자생산 수율을 악화시키는 주요 원인이 되고 있다. 따라서 플라즈마에서 입자 형성의 원인이 되는 화학반응 및 입자들의 성장 매커니즘에 대한 연구는, 1980년대 플라즈마 공정에서 입자 합성이 보고된 이래 공정의 최적화를 위해 꾸준히 연구되어왔다. 이러한 매커니즘의 연구들은, 플라즈마 화학반응에 의해 실리콘 입자 핵을 만들어 내는 과정과 입자들이 충돌에 의해 성장해가는 과정으로 나눠진다. 플라즈마 화학 반응 과정은 아레니우스 방정식에 의해 정의된 반응계수를 이용하여 플라즈마 내 전자와 이온, 중성 화학종들이 전자 온도와 전자 밀도, 챔버 온도 등에 의해 결정되는 현상을 모사한다. 또한 이 과정에서 실리콘을 포함하는 화학종들의 반응에 의해 핵이 생성 되가는 양상을 모사한다. 생성된 핵은 충돌에 의해 입자가 성장해 가는 과정의 가장 작은 입자로써 이용된다. 입자들이 성장해가는 과정은 입자들이 서로 충돌하면서 다양한 입경의 입자로 분화되어가는 현상을 모사한다. 이 과정에 의해 다양한 입경분포로 분화된 입자들은 플라즈마 내 전자에 의해 하전되며, 이러한 하전 양상은 입경에 따라 다른 분포를 보인다. 본 연구에서는 입자의 하전 분포를 고려하여, 입자들의 성장의 주요 원인인 입자간의 충돌을 대표하는 충돌주파수를 수정하는 방식을 채택하여 보다 정밀한 입자 성장 양상을 모델링하였다. Inductively coupled plasma (ICP) 타입의 저온 플라즈마 반응기에서 합성된 입자들을 Particle Beam Mass Spectrometer (PBMS)와 Scanning Electron Microscope (SEM)를 이용하여 입경분포를 측정한 데이터와 모델링에 의해 계산된 결과를 비교하여 본 모델의 유효성을 검증하였다. 검증을 위해 100~300 mtorr의 챔버 압력 조건과 100~350 W의 입력 전력 조건들을 달리하며 측정한 결과와 계산한 데이터를 조건별로 비교하였다.

• The KIPS Transactions:PartB
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• v.11B no.7 s.96
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• pp.821-830
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• 2004

In this paper, we model the downward collision of a falling object to the base. We aim to provide maximum diversity of response to physical. collision. To this end, the primary design concern of the model is to unfold the collision phenomenon in a logical and natural manner, detailed enough to construct an immersive virtual environment. To achieve these requirements, first we determine domains for the characteristic of the material of the falling objects, and select the dominant force of the collision. We formulate the collision phenomena with combination of primitive attributes and their relationships. The formulated function evaluates the results of the collision in qualitative aspects as well as in quantitative aspects. Between the collision issues, 'Collision Detection' and 'Collision Response', this paper focuses on Collision Response issue.

• The Academic Congress of Korean Shoulder and Elbow Society
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• 2006.11a
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• pp.76-84
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• 2006

석회화 건염은 회전근 개중 극상근 건에 석회가 침착되는 질환으로서 진행 양상에 따라 Formative, Resting, Resorptive phases로 나눈다. 치료는 물리 치료, Puncture, 국소 steroid 주사, 체외 충격파 등 보존적 치료에 반응을 잘 하며, 특히 resorptive phases때의 극심한 통증은 석회 침착 부위에 puncture나 needling lavege를 실시하면 즉각적인 동통 감소 효과와 함께 석회 침착의 자연 소실을 기대할 수 있다. 이러한 보존적 치료에 효과가 없을 경우 수술적 처치를 고려할 수 있는데 최근에는 대부분 관절경을 이용한 석회 제거술을 시행한다. 수술전 견관절 충돌 징후가 있거나 수술 소견상 이를 의심할 만한 소견이 있을 경우 견봉하 성형술을 함께 실시하기도 한다.

• Analyses & Alternatives
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• v.6 no.2
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• pp.5-36
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• 2022

The Russia-Ukraine War was a "three-layer compounded war" between the US and Russia, Russia and Ukraine, and Ukrainian government forces and rebels. First, the war is a phenomenon that occurred when the western sphere of influence seeking to maintain and strengthen the liberal international order and the Sino-Russian sphere of influence seeking a new alternative order collided in Ukraine, a geopolitical fault zone. Second, this war is the result of a typical 'security dilemma' phenomenon caused by the 'chain reaction' game of NATO's continuous expansion and Russia's response. Third, the Russia-Ukraine war was caused by the Russian military projection to prevent the military restoration of Donbas region by Ukraine. Until now, the Western world, led by the US, showed unexpected solidarity after the war despite subtle differences in positions. However, the non-Western world, including China, is not participating in the condemnation and sanctions against Russia. This war will be an important turning point in the existence and change of the current international order that has been formed and is operating since the end of the Cold War. The direction of maintenance/restoration, revision/change, and end/transformation of the current international order is highly likely to be determined depending on the development pattern and method of ending the war.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.32 no.6
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• pp.706-712
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• 1999

PSD (particle size distribution) for 2,000 mg/$\ell$ natural loess in seawater showed normal distribution cure at 0 minute settling time, accompanying with very large particle distribution range with its mean particle diameter of 31.6 $\mu$m and coencient of variance of $72.6\%$, With elapsed time it showed that the PSD was rapidly changed from normal distribution cure to abnormal distribution curve, steepened the right-hand side of it and its coefficient of variance was getting increased because of rapid settling of large size particles, Cumulative weight distribution showed that 2,000 mg/$\ell$ natural loess in seawater was almost $100\%$ constituted of particles bigger than 20 $\mu$m in diameter. Ratio of $V_s/(D_{bm})^{1/2}$ for loess particles in seawater was increased with increase of particle size in geometrical progression. Almost all loess particles in seawater had Stokes settling velocity not less than 2,255 times of Brownian diffusion coefficient, There was almost to EDL (about 0.4 nm) around natural loess particles in seawater, Thus, there was always LVDW attractive force between loess particles approaching each other in seawater, and almost no EDL repulsive force. Loess particles were not always in the condition of easy floe formation. Concentration of natural loess in seawater increasing from 400 mg/$\ell$ to 10,000 mg/$\ell$, characteristics of the settling was changed from Type I settling (discrete settling) to Type II settling (flocculation settling). PVD (particle volume distribution) showed that natural loess particles in seawater were largely constituted of two types of particles, such as rapidly settling particles and suspended and dispersed particles for a long time. Amount of the latter was much less than that of the former.

• Journal of Preventive Medicine and Public Health
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• v.15 no.1
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• pp.187-196
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• 1982

The followings are the results of the study on industrial accidents occurred at 12 factories manufacturing metal products during the period of 2 years from January 1980 to December 1981 in the area of Yong-Dung-Po in Seoul. The results of the study are as follows: 1. The incidence rate of industrial injuries was 45.7 per 1,000 workers of the sample group and the rate of male (54.0) was three times higher than that of female (17.5). 2. In age groups, the highest rate was observed in the group of under 19 years old with 83.5, while the lowest in the group of 40s. 3. It was found that those who had short term of work experience produced a higher rate of injuries, particularly, the group of workers with less than 1 year of experience showed the highest rate of it as 48.1%. 4. In working time, the highest incidence rate occurred 3 and 7 hours after the beginning of their working showing the rate of 6.0 and 6.1 per 1,000 workers, respectively. 5. The highest incidence rate was observed on Monday as 8.4 per 1,000 workers, and it was 18.3% in aspect of the days of a week. 6. In aspect of the months of a year, the highest incidence was observed on July 1,000 workers and the next was on March as 4.8. These figures account for 11.8% of total occurrence in respective month. as 5. 4 per and 10.5% 7. In causes of injuries, the accident caused by power driven machinery showed the highest rate with 37.5%, the second was due to handling without machinery with 17.2%, and the third was due to falling objects with 14.2%, and striking against objects with 10.2%, and so on. 8. By parts of the body affected, the most injuries 84.3% of them occurred on both upper and lower extremities with the rate of 58.8% for the former and 25.5% for the latter. Fingers were most frequently injured with a rate of 40.3%. Comparing the sites of extremities affected, rate of injuries on the right side was 55.0% and 45.0% on the left side. 9. In the nature of injury, laceration and open wound were the highest with 34. 0%, the next was fracture and dislocation with 31. 9%, and sprain was the third with 8.1%. 10. On the duration of treatment, it lasted less than one month in 68.9% of the injured cases, of which 14.5% of the cases were recovered within 2 weeks, and 54.4% of them were treated more than 2 weeks. And the duration of the treatment tended to be prolonged in larger industries. 11. The ratio of insured accidents to uninsured accidents was 1 to 4.7.