• 한국기후변화학회지
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• 제2권2호
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• pp.79-91
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• 2011

본 연구에서는 기후변화와 대기환경 사이의 통합적 상호작용 연구를 위하여 전 지구규모 기후모델(CCSM3) 결과를 지역 규모 기후모델(MM5)의 초기 및 경계 조건으로 사용할 수 있도록 역학적 상세화(Downscaling) 기법을 개발하였다. 개발된 상세화 기법에서는 위 경도 좌표계로 이루어진 CCSM3 결과를 Lambert-Conformal Arakawa-B 격자 체계로, CCSM3의 hybrid-vertical coordinate를 MM5의 sigma coordinate로 대체하는 과정과 CCSM3 모델 수행 결과와 모델 수행에 필요한 변수들 간의 일치화 과정이 포함된다. 전 지구 규모 모델 결과들이 지역 규모 모델의 입력값으로 역학적 규모 축소되는 과정을 검증하기 위해 공간 분포 및 통계분석을 수행한 결과, 여름철과 겨울철의 기온 및 강수량 패턴이 동아시아 영역 및 한반도 지역에 대해 기존 관측을 이용한 결과와 매우 유사한 패턴을 보였으며, 통계 분석 결과 모델 예측지수가 기온의 경우 0.9 이상의 좋은 값이 나타났으며, 상관성 역시 0.9 수준의 결과를 보여 인터페이스 구축이 성공적으로 수행되었음을 알 수 있다.

• 한국운동역학회지
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• 제28권2호
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• pp.135-141
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• 2018

Objective: The purpose of this study was to investigate the effect of functional ankle instability (FAI) and surgical treatment (ST) on postural stability and leg stiffness during vertical-drop landing. Method: A total of 21 men participated in this study (normal [NOR]: 7, FAI: 7, ST: 7). We estimated dimensionless leg stiffness as the ratio of the peak vertical ground reaction force and the change in stance-phase leg length. Leg length was calculated as the distance from the center of the pelvis to the center of pressure under the foot. Furthermore, the analyzed variables included the loading rate and the dynamic postural stability index (DPSI; medial-lateral [ML], anterior-posterior [AP], and vertical [V]) in the initial contact phase. Results: The dimensionless leg stiffness in the FAI group was higher than that of the NOR group and the ST group (p = .018). This result may be due to a smaller change in stance-phase leg length (p = .001). DPSI (ML, AP, and V) and loading rate did not show differences according to the types of ankle instability during drop landing (p > .05). Conclusion: This study suggested that the dimensionless leg stiffness was within the normal range in the ST group, whereas it was increased by the stiffness of the legs rather than the peak vertical force during vertical-drop landing in the FAI group. Identifying these potential differences may enable clinicians to assess ankle instability and design rehabilitation protocols specific for the impairment.

• 한국가시화정보학회:학술대회논문집
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• 한국가시화정보학회 2006년도 추계학술대회 논문집
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• pp.68-72
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• 2006

Vertical fence has the coherent flow structure in front of the fence. In the present study, the wake change due to the flow separator in front of the vertical fence was experimentally investigated. Quantitative method was applied to study the separated shear flow field. The results show the flow separator changes the downstream shear flow and alters the curvature of separated shear layer As the freestream velocity increased, the reattachment length also increased.

• 한국운동역학회지
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• 제13권3호
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• pp.27-46
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• 2003

The purposes of this study were to determine the functions of actions of the limbs during each of the three support phases of the triple jump and their relationships with the performance of the triple jump. Four elite male triple jumpers were participated as subjects. The statistical analyses used were the Pearson product moment correlation coefficient for establishing relationships and simple regression analyses to determine and compare the relationships between the change of the horizontal velocity and the change of the vertical velocity during different support phases. A level of significance at p<.05 was set. The actions of the arms were responsible for about 25%, 25%, and 30% of the decrease in the horizontal velocity of the whole body center of gravity during the support phases of the hop, step, and jump, respectively. The change in the velocities of the whole body center of gravity due to the actions of the free limbs were significantly related with the whole body center of gravity during each support phase. The action of the support leg was associated with the decrease in the horizontal velocity and the increase in the vertical velocity of the whole body center of gravity during each support phase.

• 태양에너지
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• 제12권1호
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• pp.48-58
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• 1992

온도가 일정한 외벽을 열원으로 하는 수직 원통형 용기내에 채워진 물질(PCM)의 내향용융 과정에서 용기의 경사각의 변화에 따른 상변화 물질 내의 온도 분포, 용융율, 용융 에너지 등을 실험적으로 연구, 분석하였다. 상변화 물질로는 용융점 온도가 $42.5^{\circ}C$인 n-docosane paraffin($C_{22}H_{46}$)을 사용하였다. 수직 원통형 용기내에서 PCM 용융의 열전달 기구는 자연 대류에 의한 용융이 지배적인 반면 경사진 용기 내에서 용융은 자연 대류 및 고상 PCM과 용기 벽면의 직접 접촉에 의한 조합된 열전달 현상으로 나타났으며, 경사진 용기 내에서 파라핀의 용융율 및 용융에너지는 동일 온도 조건에서 수직 원통형 용기에서 보다 높은 값을 나타내었다.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2003년도 추계학술대회
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• pp.90-96
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• 2003

Numerical analyses have been performed to obtain the absorption heat and mass transfer coefficients and the absorption mass flux from a falling film of LiBr solution. In the present study, the behavior of laminar-wavy falling film in the vertical absorber was studied analytically and experimentally. The change of absorption performance on mean film thickness, wave amplitude, wave celerity was analysed. The heat and mass transfer equations are solved simultaneously to give the temperature and concentration variations at the LiBr solution/refrigeration vapor interface and at the wall. Effects of uniform film, wavy film and film Reynolds number on the heat and mass transfer coefficients have been estimated. The analytical results of the uniform and wavy falling film in the bare tube was higher than experimental result for $Rd_{t}<100$. The absorption performance showed the maximum at the wavy film by the insert device(spring).

• 농업과학연구
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• 제40권3호
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• pp.243-252
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• 2013

This study was carried out to investigate safety evaluation of agricultural reservoirs due to raising the embankment. The seepage analysis and large-scale model test were performed to compare and analyze the pore water pressure(PWP), leakage quantity, settlement and piping phenomenon in the inclined core type and the vertical core type embankments. The PWP after raising the embankment showed smaller than before raising the embankment and the stability for piping after raising the embankment. The allowable seepage quantity and the allowable leakage for the steady state and transient conditions is within the range of safe management standard. After raising the embankment in the inclined core, there was no infiltration by leakage. For the vertical core, the PWP showed a large change by faster infiltration of pore water than in the inclined core. In a rapid drawdown, inclined core was remained stable but the vertical core showed a large change in PWP. Settlement after raising the embankment showed larger amounts of settlement than before raising the embankment. The leakage quantity before raising the embankment and the inclined core type showed no leakage. From the result, an instrument system that can accurately estimate a change of PWP shall be established for the rational maintenance and stabilization of raising the embankment for agricultural reservoirs.

• 한국구조물진단유지관리공학회 논문집
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• 제12권5호
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• pp.116-124
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• 2008

본 연구에서는 원형수직구 굴착에 따른 Ring Beam의 거동을 평가하기 위하여 현장계측 자료의 분석과 평가, 굴착심도 변화에 따른 Ring Beam의 응력 특성 등의 비교분석을 구조해석에 기초하여 평가하였다. 그 결과, Ring Beam의 거동은 현장계측 및 구조해석 결과에서 유사한 경향을 나타내는 것을 알 수 있었다. 이로부터 굴착심도 변화에 따른 Ring Beam 거동은 본 연구에서 제안한 구조해석에 의해 예측할 수 있는 것을 확인하였다.

• Maxillofacial Plastic and Reconstructive Surgery
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• 제28권1호
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• pp.21-26
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• 2006

Considering the skeletal class III malocclusion that complains of mandibular prognathism, there have been some studies of the mandibular change for comparing the changes of pre operative with post operative state. Nowadays it is common to do the orthognathic 2-jaw surgery for the correction of the maxillary deficiency, the post operative stability and the esthetics. We compare and analyze the changes of soft tissue around the nose and the lip with the changes in the direction and the amount of maxilla. Patients who were diagnosed as maxillofacial deformity and received orthognathic surgery of both jaws at Yongdong Severance hospital from 2001 through 2003 were included in this study. Their lateral cephalograms were analyzed, and the post operative change of hard tissue and soft tissue were studied. Upon analyzing the preoperative cephalograms and 6 month post operative cephalograms, there were significant in the vertical change of Labialis superius(Ls) and Stomion(Stm) in soft tissue in relation to the vertical change of skeletal landmarks (Anterior Nasal Spine, Subspinale, Prosthion, Incision Superious). In addition, there were no significance in horizontal movement of the skeletal landmarks among groups. In terms of hard tissue landmarks, group 3(maxillary posterior impaction and advancement surgery group) showed significantly greater change in the vertical movement of Anterior Nasal Spine(ANS), Subspinale(A), Prosthion(Pr), and Incision Superious(Is) compared with other groups. In terms of soft tissue change, group 3 showed more significant change in the vertical movement of Ls and Stm. This study calculated the changes of the skeletal and soft tissue landmarks in order to act as a guide in planning and performing the surgery and as a reference in predicting the postoperative change of facial appearance.

• 한국기후변화학회지
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• 제7권3호
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• pp.357-371
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• 2016

Buildings in the city acts as a cause of distorted wind direction, wind speed, causing the stagnation of the air flow. In the recent trend of climate change can not but consider the temperature rise of the urbanization. This study was aimed to analyze the thermal comfort of planetary boundary layer in different artificial constructions areas which has a direct impact on urban climate, and estimating the warming phenomena. Envi-met model was used to consider the urban structure associated with urban growth in order to precisely determine the impact of the building on the city weather condition. The analyzed values of thermal comfort index were temperature, wind speed, horizontal and vertical turbulent diffusivity. In particular, analysis of the PPD(Predicted Percentage of Dissatisfied) represents the human thermal comfort. In this study, by adjusting the arrangement and proportion of the top floor building in the urban it was found that the inflow of the fresh air and cooling can be derived low PPD. Vertical heat flux amount of the city caused by climate change was a factor to form a high potential temperature in the city and the accumulation of cold air does not appear near the surface. Based on this, to make the city effectively respond to climate change may require a long-term restructuring of urban spatial structure and density management.