• 제목/요약/키워드: Sea&Air

검색결과 1,167건 처리시간 0.031초

선박충돌 문제에 대한 해상교량의 유지관리 (Maintenance of the Sea-crossing Bridge for Ship Collision Problems)

  • 배용귀;이성로
    • 한국구조물진단유지관리공학회 논문집
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    • 제20권6호
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    • pp.56-64
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    • 2016
  • 해상교량의 선박충돌 문제는 기본적으로 선박의 충격력에 의한 부가 하중의 빈도를 추정하는 것이므로 특정한 수용 기준을 만족하도록 설계하는 것도 중요하지만 공용기간동안 이러한 충돌 위험의 증가분을 어떻게 유지관리 해야 하는지도 매우 중요하다. 본 논문에서는 인천대교를 대상으로 선박충돌 문제에 대한 중간점검을 위하여 관련 계획, 주경간장, 형하고 및 충돌 위험도를 검토하였다. 특히, 충돌 위험의 증가분에 대하여 근시적인 해결방안으로 관련 연구결과 및 운항관련 지침 등을 검토하여 최적화된 운항 속도를 8노트로 제시하였으며, 근본적인 해결방안으로 설계 단계에서 대상선박 및 통행량의 합리적인 예측을 위한 기본 절차를 수립하고 예측의 불확실성을 수용할 수 있는 확률론적 예측 기법을 제안하였다. 향후 선박충돌 관련 유지관리에 대한 추가적인 연구와 공용중인 다른 해상교량의 즉각적인 중간점검이 필요할 것으로 판단된다.

울릉도에서 구름 유입시 관측한 해양대기경계층의 열수지에 관한 사례연구 (A Case Study on the Heat budget of the Marine Atmosphere Boundary Layer due to inflow of cloud on observation at Ulleungdo)

  • 김희종;윤일희;권병혁
    • 한국지구과학회지
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    • 제25권7호
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    • pp.629-636
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    • 2004
  • 구름이 유입하는 경우 해양대기경계층의 발달을 분석하기 위하여, 울릉도에서 관측한 레윈존데 자료와 AWS 자료, 위성사진, 동해에 설치된 부이 자료를 이용하였다. 이 자료를 이용하여 열의 이류와 표층 열속, 구름 유입에 따른 복사에너지를 추정하였다. 혼합층 내의 열 변화 및 혼합층의 발달을 표층 열속과 구름에 의한 장파복사속으로 설명하였다. 열속의 변화를 알아보기 위해 벌크법을 이용하였다. 울릉도, 동해상의 부이, 포항에서 관측한 자료를 이용한 열수지 방정식으로 대기경계층의 열보존 관계를 분석하였다. 구름의 유입으로 인해 일몰 후 지면의 복사냉각이 방해되고, 구름에서 장파복사가 방출된다. 그로 인해 야간에 오히려 기온이 증가하였다. 또 남서쪽으로부터 따뜻한 공기가 이류되어, 하층 대기의 온도를 증가시켰다. 이러한 이유로 혼합층이 파괴되지 않고, 잔류층을 형성하며 남아있었다.

수도권지역 도시화가 국지기상에 미치는 영향 모델링 (Modeling the Impacts of Increased Urbanization on Local Meteorology in the Greater Seoul Area)

  • 강윤희;김유근;오인보;황미경;송상근
    • 한국환경과학회지
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    • 제19권12호
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    • pp.1361-1374
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    • 2010
  • The impact of urbanization on local meteorology (e.g., surface temperature, PBL height, wind speed, etc.) in the Greater Seoul Area (GSA) was quantitatively evaluated based on a numerical modeling approach during a 1-month period of 2001 (9 Sep. through 8 Oct. 2001). The analysis was carried out by two sets of simulation scenarios: (1) with the global land use and topographic data from the U.S. Geological Survey (USGS) in 1990s (i.e., LU-USGS case) and (2) with the land use data from the Environmental Geographic Information System (EGIS) along with the 3 sec elevation data from the Shuttle Radar Topography Mission (SRTM) in 2000s (i.e., LU-EGIS case). The extension of urban areas in the GSA (especially, the southern parts of Seoul) accounted for 1.8% in the LU-USGS case and 6.2% in the LU-EGIS case. For the simulations, the surface temperature and PBL height due to urbanization in the LU-EGIS case was higher (the differences of up to $0.1^{\circ}C$ and 36 m, respectively) than those in the LU-USGS case, whereas the wind speed (up to 0.3 $ms^{-1}$) in the former was lower than that in the latter at 1500 LST. The increase in surface temperature due to urbanization in the GSA (especially, the southern parts of Seoul) was led to the strong convergence of air masses, causing the early sea breeze and its rapid propagation to inland locations. In addition, the vertical mixing motion in the extended urban areas for the LU-EGIS case was predicted to be stronger than that for the LU-USGS case and vice versa for the original urban areas.

개선 된 구조를 갖는 능동 레이더 반사기 개발에 관한 연구 (A Study on the Development of the Active Radar Reflector with Enhanced Structure)

  • 정종혁;강상욱;조영창;최병진;윤정오;홍영호
    • 한국산업정보학회:학술대회논문집
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    • 한국산업정보학회 2000년도 춘계학술대회논문집
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    • pp.59-64
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    • 2000
  • 능동 레이더 반사기는 지금까지는 특히 비행물체와 미사일의 레이더 유효 반사 면적을 효과적으로 증가시키기 위한 군사적 응용에만 사용이 제한되어져 왔기 때문에 그다지 친숙한 용어는 아니다. 레이더 트랜스폰더의 가장 잘 알려진 응용은 군용의 피아 식별 장치 (IFF ; Identification Friend or Foe)와 이것의 민간 항공부문이고, 항공 교통 관제(An , hir Traffic Control)를 위한 2차 감시 레이더(SSR : Second Surveillance Radar), 그리고 보다 최근에는 전 세계 해상 조난 및 안전 제도(GMDSS ; Global Maritime Distress and Safety System)의 수색 구조용 트랜스폰더(SART ; Search And Rescue Transponder)등이 있다. 최근 연안이나 대양에서의 해난사고가 빈번히 발생되고 있으므로, 이로 인한 해양오염이 심각한 실정이다. 이제는 전통적인 항해표지 및 시설로써 해상교통의 안전을 유지하기에는 충분치 못하며, 새로운 개념과 구조가 적용되어야만 한다. 따라서 본 연구에서는 개선된 구조를 가진 능동 레이더 반사기를 제안하고 제작하였다. 제작된 시스템은 기존의 시설에 비해 높은 성능 향상을 보인다.

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접합대순환모형의 초기조건 생산방법에 따른 북반구 겨울철 기온과 해수면 온도의 계절 예측성 비교 연구 (Comparative Study on the Seasonal Predictability Dependency of Boreal Winter 2m Temperature and Sea Surface Temperature on CGCM Initial Conditions)

  • 안중배;이준리
    • 대기
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    • 제25권2호
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    • pp.353-366
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    • 2015
  • The impact of land and ocean initial condition on coupled general circulation model seasonal predictability is assessed in this study. The CGCM used here is Pusan National University Couple General Circulation Model (PNU CGCM). The seasonal predictability of the surface air temperature and ocean potential temperature for boreal winter are evaluated with 4 different experiments which are combinations of 2 types of land initial conditions (AMI and CMI) and 2 types of ocean initial conditions (DA and noDA). EXP1 is the experiment using climatological land initial condition and ocean initial condition to which the data assimilation technique is not applied. EXP2 is same with EXP1 but used ocean data assimilation applied ocean initial condition. EXP3 is same with EXP1 but AMIP-type land initial condition is used for this experiment. EXP4 is the experiment using the AMIP-type land initial condition and data assimilated ocean initial condition. By comparing these 4 experiments, it is revealed that the impact of data assimilated ocean initial is dominant compared to AMIP-type land initial condition for seasonal predictability of CGCM. The spatial and temporal patterns of EXP2 and EXP4 to which the data assimilation technique is applied were improved compared to the others (EXP1 and EXP3) in boreal winter 2m temperature and sea surface temperature prediction.

해양혼합층 모델 적용을 통한 고해상도 지역예측모델 성능개선에 대한 연구 (A Study on Improvement of High Resolution Regional NWP by Applying Ocean Mixed Layer Model)

  • 민재식;지준범;장민;박정균
    • 대기
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    • 제27권3호
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    • pp.317-329
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    • 2017
  • Ocean mixed layer (OML) depth affects diurnal cycle of sea surface temperature (SST) induced by change of solar radiation absorption and heat budget in ocean. The diurnal SST variation can lead to convection over the ocean, which can impact on localized precipitation both over coastal and inland. In this study, we investigate the OML characteristics affecting the diurnal cycle of SST for the Korean Peninsula and surrounding areas. To analyze OML characteristics, HYCOM oceanic mixed layer depth (MLD) and wind field at 10 m from ERA-interim during 2008~2016 are used. In the winter, MLD is deeply formed when the strong wind field is located on perpendicular to continental slope over deep seafloor areas. Besides, cooling SST-induced vertical mixing in OML is reinforced by dry cold air originated from Siberia. The OML in summer is shallowly distributed about 20 m. In order to estimate the impact of OML model in high resolution NWP model, four experimental simulations are performed. At this time, the prognostic scheme of skin SST is applied in NWP to simulate diurnal SST. The simulation results show that CNTL (off-OML) overestimates diurnal cycle of SST, while EXPs (on-OML) indicate similar results to observations. The prediction performance for precipitation of EXPs shows improvement compared with CNTL over coastal as well as inland. This results suggest that the application of the OML model in summer season can contribute to improving the prediction for performance of SST and precipitation over coastal area and inland.

Chemical Properties of Indoor Individual Particles Collected at the Daily Behavior Spaces of a Factory Worker

  • Ma, Chang-Jin;Kang, Gong-Unn;Sakai, Takuro
    • Asian Journal of Atmospheric Environment
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    • 제11권2호
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    • pp.122-130
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    • 2017
  • The main purpose of the study was to clarify the properties of individual particles collected at each behavior space of a factory worker. The samplings of size-segregated ($PM_{2.1-1.1}$ and $PM_{4.7-3.3}$) indoor particles were conducted at three different behavior spaces of a factory worker who is engaged in an auto parts manufacturing plant (i.e., his home, his work place in factory, and his favorite restaurant). Elemental specification (i.e., relative elemental content and distribution in and/or on individual particles) was performed by a micro-PIXE system. Every element detected from the coarse particulate matters of home was classified into three groups, i.e., a group of high net-counts (Na, Al, and Si), a group of intermediate net-counts (Mg, S, Cl, K, and Ca), and a group of minor trace elements (P, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, and Pb). The results of EF for $PM_{4.7-3.3}$ in home indicated that several heavy metals were generated from the sources within the house itself. An exceptional feature shown in the individual particles in workplace is that Cr, Mn, and Co were clearly detected in both fine and coarse particles. Cluster analysis suggested that the individual coarse particles ($PM_{4.7-3.3}$) collected at the indoor of factory were chemically heterogeneous and they modified with sea-salt, mineral, and artificially derived elements. The principal components in individual coarse particles collected at restaurant were sea-salt and mineral without mixing with harmful trace elements like chromium and manganese. Compared to the indoor fine particles of home and restaurant, many elements, especially, Cl, Na, Cr, Mn, Pb, and Zn showed overwhelmingly high net-counts in those of factory.

동해안의 복잡지형에서 기상장 개선에 따른 CALPUFF 모델의 평가 (Evaluation of the CALPUFF Model Using Improved Meteorological Fields in Complex Terrain of East Sea Coast)

  • 이종범;김재철
    • 한국대기환경학회지
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    • 제25권1호
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    • pp.15-25
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    • 2009
  • Donghae city is one of the most representative cement industrial city in Korea. The area is faced with the East Sea to the East and with high montane region of Tae-Back mountain range to the West. Many pollutant sources of air pollution are located near the coast, but the largest point sources of the region are located at the bottom of the mountain area in Donghae city. The local wind is highly affected by local topography and plays an important role in transport and dispersion of contaminants from the pollution sources. This study was designed to evaluate enhancement of MM5 predictions by using Four Dimensional Data Assimilation (FDDA), the SONDE data and the national meteorological station, data only. The alternative meteorological fields predicted with and without FDDA were used to simulate spatial and temporal variations of NOx in combined with Atmospheric Dispersion Models (CALPUFF). For the modeling domain, the alternative meteorological fields with 1.1 km spatial resolution were interpolated to the CALMET with 0.5 km resolution. The vertical layers set to have 35 and 12 layers for MM5 and CALPUFF, respectively. MM5 with the FDDA did not resulted in significant improvement of meteorological field prediction in Donghae region, which is primarily because of complex geography and wind scheme. The result of CALPUFF, however, showed reduction of uncertainty errors by using the interpolation scheme of the actual measurement data.

A Seasonal Indoor Thermal Conditions of a Newly-launched Training Ship

  • Hwang, Kwang-Il;Shin, Dong-Keol;Lee, Jin-Uk;Lee, Sang-Il
    • 한국항해항만학회지
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    • 제33권4호
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    • pp.289-294
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    • 2009
  • The living performances of crews and passengers in cabins have been less received attention, while Korea is a top leading country in ship building industry. To develop a high value added ships like 5-star cruisers, researches on the comfort and productivity in cabins should be carried out with urgent. The purpose of this study is to measure and analyze of the ship's indoor thermal conditions in spring, summer and winter, and also to compare the seasonal differences, of which conditions are supplied from and controlled by marine HVAC The temperature, humidity and air supply volume of 5 different needs of cabins on a training ship were measured through a year, which was launched at Dec. 2005 and totally 246 crews can go on board for education. The following results were obtained: (1)In the spring, the temperature in cabins was measured as $20{\sim}25^{\circ}C$ and humidity was below 30%. (2)In the summer, the temperatures was controlled at $21{\sim}27^{\circ}C$ in almost cabins and humidity was between $40{\sim}60%$ which is known as comfort conditions. (3)In the winter, temperature and humidity was maintained between $19{\sim}26^{\circ}C$, and humidity was between $10{\sim}50%$. (4)It is clear that the humidity conditions in cabins are not properly controlled at all through a year to satisfy the Comfort Standards provided by ASHRAE and/or ISO, In conclusion, humidification and dehumidification of cabins must be treated with importance for more comfort living and working environments for crews and passengers.

배관 재질 및 길이에 따른 대규모 시설원예단지용 미활용 에너지 시스템의 성능 평가 (Effects of Pipe Network Materials and Distance on Unused Energy Source System Performance for Large-scale Horticulture Facilities)

  • 이재호;윤여범;현인탁;이광호
    • KIEAE Journal
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    • 제14권4호
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    • pp.119-125
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    • 2014
  • This study investigated the effects of pipe network materials and distance on system performance utilizing unused energy sources in large-scale horticulture facility. For this, the modeling was performed with a 100 m long and 100 m wide rectangular shaped glass house having an area of 1ha ($10,000m^2$) using EnergyPlus software. The heat sources considered were air source, geothermal heat, power plant waste heat, sea water heat, and river water. The temperature variation of the fluid with regard to pipe material and distance from the heat source and the resultant heat pump electricity consumptions were calculated. It turned out that the fluid temperature reaching the heat pump increased as the distance from the heat source increased in case of sea water and river water, which have higher temperatures than the surrounding soil, improving the heat pump efficiency. It was vice versa in case of the power plant waste heat. In addition, pipe material of PVC showed the smallest effect on the system performance variation due to the lowest thermal conductivity, compared to PB and HDPE.