• 제어로봇시스템학회:학술대회논문집
• /
• 2004.08a
• /
• pp.454-459
• /
• 2004

This paper considers the problem of satellite's orbit control and a solution based in Linear Matrix Inequalities (LMI) is proposed for the case of Low Earth Orbiters (LEO). In particular, the modelling procedure and the algorithm for control law synthesis are tested using as study case the European Gravity Field and Ocean Circulation Explorer satellite (GOCE), to be launched by the European Space Agency (ESA) in the year 2006. The scientific objective of this space mission is the recovering of the Earth gravity field with high accuracy (less than 10${\mu}m$/${\mu}m$) and spatial resolution (better than 100km). In order to meet these scientific requirements, the orbit control must guarantee stringent specifications in terms of environmental disturbances attenuation (atmospheric drag forces) even in presence of high levels of model uncertainty.

• Proceedings of the Korea Water Resources Association Conference
• /
• 2005.05b
• /
• pp.138-142
• /
• 2005

The change of precipitation and temperature due to the global. warming eventually caused the variation of water availability in terms of potential evapotranspiration, soil moisture, and runoff. In this reason national long-term water resource planning should be considered the effect of climate change. Study of AOGCM-based scenario to proposed the plausible future states of the climate system has become increasingly important for hydrological impact assessment. Future climate changes over East Asia are projected from the coupled atmosphere-ocean general circulation model (AOGCM) simulations based on Intergovernmental Panel on Climate Change (IPCC) Special Report on Emissions Scenarios (SRES) A2 and B2 scenarios using multi-model ensembles (MMEs) method (Min et al. 2004). MME method is used to reduce the uncertainty of individual models. However, the uncertainty increases are larger over the small area than the large area. It is demonstrated that the temperature increases is larger over continental area than oceanic area in the 21st century.

• 한국전산유체공학회:학술대회논문집
• /
• 2000.05a
• /
• pp.14-19
• /
• 2000

A coupled general circulation model (GCM) of the global atmosphere, oceans and lands is used for finding the future climate at times of doubled carbon dioxide concentration (DCDC) of the atmosphere. Two runs of the model were made in order to find the future change. Global changes at times of DCDC may be characterized by a global warmig of $1.4^{\circ}C$, a $3\%$ global precipitation increase, and an increase in the surface available water (SAW) over the global land among others. The estimated increase in SAW over the land implies that river discharge is likely to increase with increased chance of severe weather as a result of the future global warming.

• The Korean Journal of Applied Statistics
• /
• v.22 no.6
• /
• pp.1143-1152
• /
• 2009

A canonical correlation analysis(CCA)-based method is proposed for prediction of future climate change which combines information from ensembles of atmosphere-ocean general circulation models(AOGCMs) and observed climate values. This paper focuses on predictions of future climate on a regional scale which are of potential economic values. The proposed method is obtained by coupling the classical CCA with empirical orthogonal functions(EOF) for dimension reduction. Furthermore, we generate a distribution of climate responses, so that extreme events as well as a general feature such as long tails and unimodality can be revealed through the distribution. Results from real data examples demonstrate the promising empirical properties of the proposed approaches.

• KCID journal
• /
• v.17 no.2
• /
• pp.49-56
• /
• 2010

This study was carried out to survey for morphological change of lower tidal flat near Byunsan-Gosapo beach using single-beam echosounder and sound velocity profiler. Since October 2009 in the center of the region, the erosion occurred about 10~50cm, while either side of the study area is little change. Erosion occurred at the beach, each beach area in the southwest area rather than further accumulation occurred sandbank formed. Observed in the study area near the center of the erosion is the result of ongoing changes that were temporarily due to seasonal changes is not clear. However, the northwestward waves were expected to be a major source of erosion. Because of this, continue to observe the terrain and the local ocean circulation studies will be required.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
• /
• 2001.05a
• /
• pp.755-758
• /
• 2001

Topex/poseidon 위성의 자료를 통하여 남인도양의 암스테르담- 크호제트- 케르겔른 지역에 대한 표층 순환과 해수면 변화의 시ㆍ공간적인 해석을 쉽게 수행 할 수 있었다. 각 지역에서의 시ㆍ공간적인 변화 특성들을 보면, 암스테르담지역은 서쪽으로 전파하는 로쓰비파가 존재한다. 이때 이 파는 동쪽으로 전파하는 남극순환해류의 영향을 받는다. 1993년 늦가을에서 초겨울 동안에 분지의 동부지역에서 해수면이 급격히 떨어졌다. 이곳은 남극순환해류(아규라스순환반류전선과 아열대전선)의 북부에서 발전하는 시계방향(cyclonic)의 와동류가 예외적으로 강하게 북쪽으로 상승했다가 이어서 급격히 남쪽으로 하강했던 것과 관련된다. 쌩뽈지역은 5cm 정도의 해수면 진동과 함께 약 130일 정도의 주기성을 보였다. 서쪽으로 전파하는 신호인 자유 표면의 진동이 실제로 조사되었다.

• 한국신재생에너지학회:학술대회논문집
• /
• 2009.11a
• /
• pp.590-593
• /
• 2009

Tidal current power system is one of ocean renewable energies that can minimize the environmental impact with many advantages compared to other energy sources. Not like others, the produced energy can be precisely predicted without weather conditions and also the operation rate is very high. To convert the current into power, the first device encountered to the incoming flow is the rotor that can transform into rotational energy. The performance of rotor can be determined by various design parameters including numbers of blade, sectional shape, diameter, and etc. The stream lines near the rotating rotor is very complex and the interference effects around the system is also difficult to predict. This paper introduces the experiment of rotor performance and also the effect of design parameter on the performance of HAT rotor by CFD.

• Journal of the Korea Institute of Military Science and Technology
• /
• v.12 no.1
• /
• pp.29-36
• /
• 2009

Realtime tide and storm-surge computations for the Yellow Sea were conducted using the Parallel Finite Element Model. For these computations a high resolution grid system was constructed with a minimum node interval of loom in Gyeonggi Bay. In the modeling, eight main tidal constituents were analyzed and their results agreed well with the observed data. The realtime tide computation with the eight main tidal constituents and the storm-surge simulation for Typhoon Sarah(1959) were also conducted using parallel computing system of MPI-based LINUX clusters. The result showed a good performance in simulating Typhoon Sarah and reducing the computation time.

• Proceedings of the Korea Water Resources Association Conference
• /
• 1987.07a
• /
• pp.223-234
• /
• 1987

A weakly nonlinear solution is presented for the two-dimensional wave kinematics forced by a generic wavemaker of variable-draft. The solution is valid for both piston and hinged wavemakers of variable-draft that may be double articulated. The second-order propagating waves generated by a planar wave board are composed of two components; viz., a Stokes second-order wave and a second-harmonic wave forced by the wavemaker which travels at a different speed. A previously neglected time-independent solution that is required to satisfy a kinematic boundary condition on the wavemaker as well as a mixed boundary condition on the free surface is included for the first time. A component of the time-independent solution is found to accurately estimate the mean return current(correct to second-order) in a closed wave flume. This mean return current is usually estimated from kinematic considerations by a conservation of mass principle.

• Korean Journal of Remote Sensing
• /
• v.20 no.5
• /
• pp.307-313
• /
• 2004

The trajectories of 8 autonomous profiling floats deployed in the Kuroshio Extension region in February 2001 are used to depict the circulation pattern at the surface and 2000db. The corresponding sea surface topography maps created from satellite altimeter and dynamic height climatology were compared with the tracks of nearly coincident floats and were found to agree well in most cases except for the period June 5 to 16 2001. It is shown that over the period the conspicuous breakaway of the floats from an expected path is possibly associated with the abnormal path of the Kuroshio Extension such as an outbreak event, as revealed by AVHRR infrared and SeaWiFS chlorophyll-a images and cruise data in cross sections.