• Title/Summary/Keyword: 지상경계

Search Result 135, Processing Time 0.026 seconds

Numerical and Experimental Study on the Aerodynamic Characteristics of FAST Fuselages (FAST 동체의 공력특성에 대한 수치 및 실험 연구)

  • Han, Cheol-Heui;Cho, Jeung-Bo;Cho, Jin-Soo
    • Journal of the Korean Society for Aeronautical & Space Sciences
    • /
    • v.35 no.3
    • /
    • pp.177-182
    • /
    • 2007
  • The effects of three fuselage head shapes and nonplanar ground surface on the aerodynamic characteristics of FAST fuselages are investigated using a boundary element method. Wind tunnel test is also performed to validate the present method and to identify the wall effect on the frictional drag which cannot be analyzed using the present method. It is found that the channel has an effect of increasing the lift of those investigated fuselages. The optimal head shape depends on the design conditions of the FAST and its guideway channel. Comparing the calculated induced drag with the measured total drag, it can be concluded that the profile drag is independent of the ground height. Thus, the present numerical method can be applied to the conceptual design of the high-speed ground transporters if only the profile drag of the vehicle in free flight is assumed to be known.

Numerical Model study of Surface Temperature and Hydrological Budget Change for the Last Glacial Maximum (마지막 최대 빙하기의 온도 및 물수지 변화 수치모델연구)

  • Kim, Seong-Joong;Lee, Bang-Yong;Yoon, Ho-Il
    • Journal of the Korean Geophysical Society
    • /
    • v.9 no.2
    • /
    • pp.135-145
    • /
    • 2006
  • The surface temperature and hydrological budget for the last glacial maximum (LGM) is simulatedwith an atmospheric general circulation model of NCAR CCM3 at spectral truncation of T170, corespondingto a grid cel size of roughly 75 km. LGM simulations were forced with the reconstructed CLIMAP sea surface temperatures, sea ice distribution, ice sheet topography, reduced CO2, and orbital parameters.oC in winter, 5.6oC in sumer,and 6oC annual-mean. The decrease of surface temperature leads to a weakening of the hydrologicalcycle. Global-mean precipitation decreases by about 14% in winter, 17% in summer, and 13% annually.However, some regions such as the U.S., southern Europe, northern and eastern Africa, and the SouthAmerica appear to be weter in the LGM winter and Canada and the Midle East are weter in sumer. model captures detailed climate features over land.

  • PDF

Logistics Development Plan for Underground Ammunition Depots based on Network (네트워크 기반 지하형 탄약고의 물류 발전방안 연구)

  • Kim, Byungkyoo
    • Journal of Internet Computing and Services
    • /
    • v.23 no.3
    • /
    • pp.137-145
    • /
    • 2022
  • The logistics of ammunition stored in the underground ammunition warehouse has more difficulties than the logistics of ammunition stored on the ground due to the nature of the storage space. This study was conducted to solve the logistics of underground ammunition warehouse by improving these problems. And six items such as guard, safety, environment, supply system, equipment, facilities, and life management were selected for the improvement of logistics. And AHP was analyzed by Expert Choice program by conducting a survey to experts. As a result of the analysis, it was confirmed that the importance was high in the order of safety, guard, life management, equipment facilities, supply system, and environment. Based on the selected items and the results of the survey, a plan to build a network-based integrated platform that can improve logistics in an underground ammunition warehouse was presented. This study will be used as a basis for the establishment of an integrated platform when constructing an underground ammunition warehouse in the future. This study can be applied to storage facilities that store other materials in the military, and it is expected to be applied to large commercial storage facilities.

A Study on the Flow Conditions of the Combustion Air Heater Outlet for the Supersonic Combustion Experiment (초음속 연소 실험을 위한 연소식 공기 가열기 출구 유동 조건 실험 연구)

  • Lee, Eun Sung;Han, Hyung-Seok;Lee, Jae Hyuk;Choi, Jeong-Yeol
    • Journal of the Korean Society of Propulsion Engineers
    • /
    • v.26 no.1
    • /
    • pp.88-97
    • /
    • 2022
  • In this study, a vitiated air heater was designed and manufactured to supply high-temperature and high-pressure air to the ground test apparatus of a direct-connected supersonic combustor, and an experiment was performed to verify the target design point. By installing wedges at the upper boundary, lower boundary and center of the nozzle exit of the vitiated air heater, it was confirmed that the Mach number satisfies the 2.0 level, and the pressure of the combustion chamber was also satisfactory compared to the design point. In the case of temperature, the measured temperature deviation was large due to the degree of exposure of the thermocouple and the slow response characteristics. After that, the isolator was connected to the rear of the vitiated air heater, and the Mach number was measured in the same method, and the Mach number at the center of the isolator eixt was slightly reduced to 1.8~1.9.

Instantaneous Monitoring of Pollen Distribution in the Atmosphere by Surface-based Lidar (지상 라이다를 이용한 대기중 꽃가루 분포 실시간 모니터링)

  • Noh, Young-Min;Mueller, Detlef;Lee, Kwon-Ho;Choi, Young-Jean;Kim, Kyu-Rang;Lee, Han-Lim;Choi, Tae-Jin
    • Korean Journal of Remote Sensing
    • /
    • v.28 no.1
    • /
    • pp.1-9
    • /
    • 2012
  • The diurnal variation in pollen vertical distributions in the atmosphere was observed by a surface-based lidar remote sensing technique. Aerosol extinction coefficient and depolarization ratio at 532 nm were obtained from lidar measurements in spring ($4^{th}$ May - $2^{nd}$ June) 2009 at Gwangju Institute of Science & Technology (GIST) located in Gwangju, Korea ($35.15^{\circ}E$, $126.53^{\circ}N$). Unusual variations of depolarization ratio were observed for six days from $4^{th}$ to $9^{th}$ May. Depolarization ratios varied from 0.08 to 0.14 were detected at the low altitude in the morning. The altitude with those high depolarization ratios was increased up to 1.5 - 2.0 km at the time interval between 12:00 and 14:00 LT and then decreased. The temporal variations in high values of depolarization ratios from lidar measurements show good agreement in patterns with the sampled pollen concentrations measured using the Burkard trap sampler. This study demonstrates that the pollen distribution data obtained by lidar measurements can be a useful tool for investigating spatial and temporal characteristic of pollen particles.

A Psychological Interpretation of a Korean Fairy Tale "The Uproot of an Archenemy in the Underworld" from the Perspective of Analytical Psychology (<지하국 대적퇴치 설화>의 분석심리학적 해석)

  • Hyoin Park
    • Sim-seong Yeon-gu
    • /
    • v.31 no.1
    • /
    • pp.41-94
    • /
    • 2016
  • A Korean fairy tale "The uproot of an archenemy in the underworld" is discussed and interpreted from the perspective of analytical psychology. The essence of the story is as follows; When the three princesses were kidnapped by an archenemy in the underworld, a warrior appeared to save the princesses. He went to the underworld and killed the archenemy with the princesses help. When they tried to come back to the castle, he had difficulties because king's soldiers betrayed him. But a old wise man and a flying horse helped him to come back to the castle. He killed the soldiers that betrayed him and married one of the princesses and got the wealth from the underworld. The kingdom could be prosperous and peace because of the marriage. The psychological meaning of the three princesses were taken by the archenemy is that the archetypal shadow appeared from the unconscious and grasped a part of consciousness and repressed it in unconsciousness. This status could be called the lost of soul. So the warrior ego went through an unconscious trip, saving his anima from the archetypal shadow, and taking her back to consciousness and renewing the collective consciousness. The ego's trip is the individuation process like Shaman in primitive society. This fairy tale has hero motif. It reveals the feature of archetypal shadow. It also shows us man can make conscious with cautious attitude in the individuation process.

A Study on the Performance Improvement of Bar Code Reader for the Automatic Processing of the Mail Items (우편물 자동처리를 위한 바코드 판독기 성능개선에 관한 연구)

  • Park, Moon-Sung;Nam, Yun-Seok;Kim, Hey-Kyu
    • Annual Conference of KIPS
    • /
    • 2001.04b
    • /
    • pp.731-734
    • /
    • 2001
  • 우편물을 집배원이 배달하는 순서로 자동구분 처리하기 위한 요소기술 줌에서 4-state 바코드 시스템이 개발되고 있으며 우편번호, 배달순서코드, 고객정보 등이 적용될 예정이다. 기존의 고객 바코드 판독 시스템은 우편물상의 바코드 심볼로지가 존재하는 판독대상 영역의 기울기가 ${\pm}4.47^{\circ}$ 이하이고, 심볼의 훼손과 잡영이 없을 경우에 $79{\sim}100msec(35,000{\sim}45,000$통/시간)의 속도로 자동 구분 정보가 판독된다. 본 논문에서는 판독범위 및 판독성능을 개선을 위하여 CCD(Charge Coupled Device) 센서로부터 획득된 이미지상에서 존재하는 심볼로지 정보의 고속판독 방법을 제시한 것이다. 이 판독방법은 그레이(gray) 이미지 바탕면의 경계값(threshold) 기울기 분포를 기준으로 2개의 경계값을 설정하여 판독대상 정보를 획득하였다. 또한, 4-state 바코드 심볼로지의 존재 가능성 영역만을 탐색하고, 판독대상 영역에서 트래커(tracker)를 탐색하여 심볼로지의 기울기값, 심볼로지 경계값, 심볼위치 좌표값을 생성한 후 심볼값이 판독한 것이다. 판독시험 결과는 판독대상 영역의 심볼로지가 ${\pm}45^{\circ}$ 기울어지고, 잡영이 존재할 경우에도 $30{\sim}60msec(58,000{\sim}l16,000$통/시간) 이내에 판독되었다. 우편물 자동구분용 바코드 판독기로써 적용될 경우에 판독속도가 평균 57.25% 이상 개선되고, 판독범위의 확장으로 0.2%의 기계적인 오류(이송과정예서의 Jam 발생 비율)를 제외할 경우에 거의 99.8% 우편물을 판독하여 자동구분 처리할 수 있게 될 것으로 기대된다.onebook 엑세스 모들(Server Phonebook Access Module)로 구성되어 있다.외 보다 높았다(I/O ratio 2.5). BTEX의 상대적 함량도 실내가 실외보다 높아 실내에도 발생원이 있음을 암시하고 있다. 자료 분석결과 유치원 실내의 벤젠은 실외로부터 유입되고 있었고, 톨루엔, 에틸벤젠, 크실렌은 실외뿐 아니라 실내에서도 발생하고 있었다. 정량한 8개 화합물 각각과 총 휘발성 유기화합물의 스피어만 상관계수는 벤젠을 제외하고는 모두 유의하였다. 이중 톨루엔과 크실렌은 총 휘발성 유기화합물과 좋은 상관성 (톨루엔 0.76, 크실렌, 0.87)을 나타내었다. 이 연구는 톨루엔과 크실렌이 총 휘발성 유기화합물의 좋은 지표를 사용될 있고, 톨루엔, 에틸벤젠, 크실렌 등 많은 휘발성 유기화합물의 발생원은 실외뿐 아니라 실내에도 있음을 나타내고 있다.>10)의 $[^{18}F]F_2$를 얻었다. 결론: $^{18}O(p,n)^{18}F$ 핵반응을 이용하여 친전자성 방사성동위원소 $[^{18}F]F_2$를 생산하였다. 표적 챔버는 알루미늄으로 제작하였으며 본 연구에서 연구된 $[^{18}F]F_2$가스는 친핵성 치환반응으로 방사성동위원소를 도입하기 어려운 다양한 방사성의 약품개발에 유용하게 이용될 수 있을 것이다.었으나 움직임 보정 후 영상을 이용하여 비교한 경우, 결합능 변화가 선조체 영역에서 국한되어 나타나며 그 유의성이 움직임 보정 전에 비하여 낮음을 알 수 있었다. 결론: 뇌활성화 과제 수행시에 동반되는 피험자의 머리 움직임에 의하여 도파민 유리가 과대평가되었으며 이는 이 연구에서 제안한 영상정합을 이용한 움직임 보정기법에 의해서 개선되었다. 답이 없는 문제, 문제 만

  • PDF

A Study on the Method of High-Speed Reading of Postal 4-state Bar Code for Supporting Automatic Processing (우편용 4-state 바코드 고속판독 방법에 관한 연구)

  • Park, Moon-Sung;Kim, Hye-Kyu;Jung, Hoe-Kyung
    • The KIPS Transactions:PartD
    • /
    • v.8D no.3
    • /
    • pp.285-294
    • /
    • 2001
  • Recently many efforts on the development of automatic processing system for delivery sequency sorting have been performed in ETRI, which requires the use of postal 4-state bar code system to encode delivery points. This paper addresses the issue on the extension of read range and the improvement of image processing method. For the improvement of image processing procedure, applied information acquisition method through basic two thresholds onto the horizontal axial line of gray image based on reference information of 4-state bar code symbology. Symbol values are computed after creating two threshold values based on the obtained information through search of horizontal axial values. The implementation result of 4-state bar code reader are obtained the symbol values within 30~60 msec (58,000~116,000 mail item/hour)without noise removal or image rotation in spite of the incline $\pm 45^{\circ}$.

  • PDF

A Study on the Measurement of River Ice Thickness by Using X-band Scatterometer (X-밴드 산란계를 이용한 하천 얼음 두께 측정에 관한 연구)

  • Han, Hyang-Sun;Kim, Bum-Jun;Lee, Hoon-Yol
    • Geophysics and Geophysical Exploration
    • /
    • v.15 no.1
    • /
    • pp.16-22
    • /
    • 2012
  • In this study, we setup a ground-based scatterometer using an antenna of which the center frequency is 9.5 GHz (X-band), and measured radar backscatterings from air/ice and ice/water interfaces to extract ice thickness. Both of air/ice and ice/water interfaces make strong radar backscatterings and so we can clearly identify two peaks in measured data by scatterometer. By using the distance of two peaks and refractive index of ice, we confirmed that it is possible to measure ice thickness. Field survey was performed at the downstream of Jiam River flowing into Chuncheon Lake. We measured radar backscattering from river ice along a survey path and extracted ice thickness. The ice thickness map of the downstream of Jiam River was produced by using kriging which is one of well known interpolation methods. The ice thickness was about 50 cm along the mainstream while ice was thin as 30 ~ 40 cm at a fast-flowing meander. Ice thickness was particularly thinner at some locations than that of surrounding areas even in the mainstream region of constant flow. This was because of impurities in ice or artificially formed refrozen holes after fishing. We expect that this study helps to expand utilization field of X-band SAR and airborne scatterometer system.

Regional Scale Hydrology Model Application using Simulated Precipitation Data in Korea (강우모형 자료를 이용한 지역적 수문 모형의 적용)

  • Jung, Yong;Baek, Jongjin;Choi, Minha
    • 한국방재학회:학술대회논문집
    • /
    • 2011.02a
    • /
    • pp.171-171
    • /
    • 2011
  • 급격한 기상이변과 자연현상의 변화에 의해 자연재해가 발생하며, 이러한 변화로 인해 전 세계적으로 환경뿐만 아니라 방재의 중요성 또한 대두되고 있으나, 강우 강도의 예측 분야에서는 여유추정시간의 차이로 인해 방재현상에 대한 구체적인 협력을 하지 못했던 것이 사실이다. 현재 가장 많이 사용하고 있는 레이더 강우자료와 지상 우량계의 강우자료는 여유추정시간이 3시간에서 4시간 사이의 단기 예측만을 가능하게 한다. 본 연구에서는 이의 개선을 위하여 청미천 유역을 대상으로 GIS를 이용하여 CN value를 추출하고, 지역 강우 모형인 Weather Research Forecast(WRF) - Advanced Research WRF(ARW)를 통하여 모의한 강우자료에 대하여 과거 같은 기간의 강우자료와 비교 검증한 후 지역 강우 모형을 통하여 모의한 자료를 HEC-HMS의 Input자료로 활용하여 지역 유출량을 산정한다. 또한 유역의 지표면 유출 모의를 통하여 강우-유출현상과 수리-수문학적 과정을 상호 연결하고, 강우에 의한 유역 지표면에서의 유출을 도출하며, 최적화된 매개변수들의 조합을 개선하여 대상유역의 현상을 보다 유사하게 나타낼 것이다. 이와 함께 WRF-ARW 모형을 통하여 여유추정시간의 증가를 모색하며 그로인한 홍수예측 및 경계체계를 확립하기 위해 연구를 진행한다. 이 지역강우 모형의 대한민국 지형의 적용성 즉, 대한민국 지형에 가장 잘 어울리는 최적화된 매개변수들의 조합을 알아내고 그의 적용현실성을 찾아내려 한다. 더 나아가 강우에 대한 예측을 통해 홍수 경보 체계를 위한 자료로 활용할 수 있는 방안 또한 모색할 것이다.

  • PDF