2010-06-22 ~ 2010-06-25 |University of Tokyo
The natural environmental condition, such as precipitation, air temperature, humidity and radiation, varies continuously with a wide spectrum of temporal scales from seconds to years and decades. Such variations are subject to slow and fast changes of solar radiation, passages of a front and pressure systems, and frequency of precipitation. In the Asian region, the monsoon system is driving temporal variability in the natural environment and consequently it makes impact on carbon and water cycles on from local, regional to continental and global scales. Terrestrial ecosystems in Asia cover wide spectrum of biomes and climate zones and represent many vegetation types. In particular, due to rapid changes of land cover and large population pressure for economic growth, the carbon and water cycles of the terrestrial ecosystems in Asia have undergone dramatic changes over the past several decades, leading to potentially significant influences on global climate change. Under future global warming scenario, seasonal precipitation cycle can be amplified in the Asian region. There is, however, the lack of our understanding on the interplay between the Asian monsoon and terrestrial carbon and water exchanges that hinders us from better understanding of carbon and water cycles and its impact on climate change. Using the ecosystem models, my presentation will briefly discuss major challenges in modeling ecosystem carbon and water exchanges in Monsoon Asia and their interplay with the Asian monsoon.
2010-06-21 ~ 2010-06-25 |서울대학교
국내의 관련 분야 전문가들과 함께, 기초에서 응용까지의 전개 및 연구과정을 소개하고, 우리 학생들의 이 분야에 대한 연구 관심을 증대
2010-06-17 ~ 2010-06-25 |숭실대학교
A major feature of biological science in the 21st century will be its transition from phenomenological and deive science to quantitative science. Revolutionary opportunities have emerged for theoretically driven advances in biological research. Rigorous, quantitative, and atomic scale deion of complex biological systems is a grand challenge. Under physiological conditions, most biological processes occur in water, which consists of 65-90% human cell weight. Explicit deion of biomolecules and their aqueous environment, including solvent, co-solutes, and mobile ions, is prohibitively expensive. Therefore, multiscale analysis is an attractive and sometimes indispensable approach. In a series of lectures, I will discuss a number of multiscale models for biomolecular systems. In Lecture One, I will discuss Poisson-Boltzmann (PB) equation based implicit solvent model. The PB model treats the solvent as a macroscopic continuum while admitting a microscopic atomic deion for the biomolecule. It has been widely used for electrostatic solvation analysis, pH and pKa estimation, electrostatic map, electrostatic force calculation, and molecular dynamics. The derivation of the PB equation from the free energy functional will be discussed. Electrostatic force expressions will be given. In Lecture Two, I will further discuss a mathematical interface approach for obtaining highly accurate solutions of the Poisson-Boltzmann (PB) equation. A solvent-solute interface is assumed in the implicit solvent models. Rigorous solution of the PB equation requires the enforcement of interface jump conditions. Due to the complexity of the biomolecular interfaces, it is very challenging to implement the interface jump conditions. A matched interface and boundary (MIB) method has been developed in my group to obtain second-order accurate electrostatic potentials for protein and other biomolecules. A Green function approach has also been developed to overcome the difficulty of handling singular charges in the PB model. In Lecture Three, I will introduce a differential geometry based multiscale solvation model. This model utilizes differential geometry theory of surfaces for coupling microscopic and macroscopic scales at an equal footing. The biomolcule of interest is described by discrete atomic and quantum mechanical variables. While the aquatic environment is described by continuum hydrodynamic variables. I will derive coupled geometric flow and Poisson- Boltzmann (PB) equations for describing biomolecular surfaces and electrostatic potentials, respectively. The free energies of biomolecular surface, mechanical work, solvent-solute interface and electrostatic interactions are optimized in this model. Another multiscale model includes the quantum mechanics deion of the electron density of (part of) the solute molecule in the salvation analysis. This is needed in refining charge force fields and in chemical binding analysis. Applications are considered to biomolecular solvation analysis, virus surface construction and proton transport in membrane proteins. In Lecture Four, I will discuss the two different formulations of the multiscale salvation model. One is the Eulerian formulation and the other is the Lagrangian formulation. The latter has a few utilities/advantages. First, it provides an essential basis for biomolecular visualization, surface electrostatic potential map and visual perception of biomolecules. Additionally, it is consistent with the conventional setting of implicit solvent theories and thus, many existing theoretical algorithms and computational software packages can be directly employed. Finally, the Lagrangian representation does not need to resort to artificially enlarged van der Waals radii as required by the Eulerian representation in solvation analysis. However, it may encounter difficulty in surface merging and break up. For this reason, the Eulerian formulation is used in practical computations. I will discuss inter-conversion of these two formalisms. In Lecture Five, I will introduce more differential geometry based multiscale models. One of these models is originated from microfluidic and nanofluidic systems, which require the deion of solvation, fluid flows, and molecular mechanics. We derive the coupled geometric flow equation, Navier-Stokes (NS) equation, generalized Poisson- Boltzmann (PB) equation and molecular dynamics to describe the dynamics of nanofluidic systems. Finally, we discuss models for the analysis of nano-biosensors. The Nernst-Planck equation is incorporated into our fluid- electro-and geometric systems to describe the drift and diffusion of ions over the nanopores. Applications will be discussed to protein folding, ion channels, micro/nanofluidic devices, and nano-bio sensors.
2010-06-16 ~ 2010-06-18 |서울대학교
2010-05-26 ~ 2010-05-28 |제주 KAL 호텔
We examined 1) the causes of inter-model variations of surface energy partitioning (SEP) and 2) the effects of model grid size on the simulated SEP. In particular, we focus on the nonlinear effect of spatial heterogeneity in atmospheric conditions on the simulation of surface fluxes in the mesoscale model by testing their scale-invariance from a tower footprint to regional scales. The test domain was a homogeneous shortgrass prairie in the central part of the Tibetan Plateau with an eddy-covariance flux tower at the center. We found that 1) soil evaporation controls the model differences of the SEP and 2) the spatial variability resulting from changing distribution of clouds and precipitation in the model domain affected radiative forcing at the ground surface, thereby altering the partitioning of surface fluxes. Consequently, due to increasing spatial variability in atmospheric conditions, the results of the mesoscale model did not produce convergent estimates of surface fluxes with increasing grid sizes. Our finding demonstrates that an atmospheric model can underestimate surface fluxes in regional scale not necessarily due to intrinsic model inaccuracy (e.g., inaccurate parameterization) but due to scale-dependent nonlinear effect of spatial variability in atmospheric conditions.
2010-05-16 ~ 2010-01-22 |연세대학교
2010-05-13 ~ 2010-05-14 |강릉원주대학교
We conducted a sensitivity test of Joint UK Land Environment Simulator (JULES), in which the influence of to biophysical parameters on to find influential input parameters in the simulation of gross primary productivity (GPP) and ecosystem respiration (Re) was investigated for in two typical ecosystems inof Korea. For this test, we employed the whole-year observation of Using the eddy-covariance fluxes measured in 2006observations of eddy fluxes, then we evaluated the performance of the JULES in two major plant functional types in Korea: at two KoFlux sites: (1) a deciduous forest in complex terrain in Gwangneung and (2) a farmland with heterogeneous mosaic patches in Haenam. Our analysis showed that the simulated GPP and Re were most sensitive to leaf nitrogen concentration and wood biomass parameter at for the deciduous forest canopyin Gwangneung. At For the mixed farmland in Haenamcanopy, the modeled GPP was most sensitive to soil moisture content at saturation, whereas the modeled Re was most sensitive to leaf nitrogen concentration. At both sites, the model significantly overestimated both GPP and Re when the default values of input parameters were adopted. If we cConsidering the fact that the observed leaf nitrogen concentration wais only about 60% of its default value, the significant portion of the model’s overestimation can be attributed to such a discrepancy in the contrast of input parameters. Our finding suggests demonstrates that the above-mentioned key biophysical properties of the two ecosystems should be carefully evaluated carefully xamined prior to any realistically simulation and interpretation of ecosystem carbon exchange in Korea. in validating ecosystem models.
2010-04-29 ~ 2010-05-01 |카이스트
본 워크샵은 비선형 편미분 방정식의 응용, 계산 및 이론에 관한 국제 학회로 세부 주제는 비선형 보존법칙이다. 본 학회의 목적은 관련분야의 국제적인 리더들과 국내의 관련 분야 전공 수학자들을 초청해서 학문적인 교류를 하고 이를 통해서 국내 수학자들이 보다 세계적인 수준의 연구를 할 수 있도록 촉진하는데 있다. 또한 광범위한 국제적인 학술 네트워크를 만들어 서 서로의 연구 임팩트를 높이고 대한민국의 수학계가 세계 수학계에 중요한 역할을 하도록 돕고자 한다.
2010-03-28 ~ 2010-04-01 |이화여자대학교
In March 2010, we will gather leading researchers studying brain connectivity using the methods of MRI and microscopy. These methods are complementary because MRI can be applied in vivo but has low spatial resolution, whereas microscopy has high spatial resolution but is applied postmortem. We believe that it is time to bring together the MRI and microscopy communities to discuss the prospects for a complete map of the white matter connectivity of the human brain, as well as the implications of such a map for brain function.