• Title/Summary/Keyword: Energy balance model

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An Empirical Study on the Economic Development Effects on Kazakhstan Focusing on the Macroeconomic Indices: International Oil Price, Interest Rate, Real Exchange Rate (카자흐스탄 경제발전에 대한 실증연구 : 국제유가·이자율·실질환율을 중심으로)

  • Hwang, Yun-Seop;Kim, Kyung-Hee;Kim, Soo-Eun
    • International Area Studies Review
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    • v.14 no.1
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    • pp.77-97
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    • 2010
  • Recently, countries on the Caspian Sea were had heavily interested due to instability of international resource market. These countries having been developed basing on energy exports, especially Kazakhstan have drastically grown during a decades. However economy, heavily relied on the exports of energy, is influenced on fluctuation in the international energy price as well as sometimes exposed at Dutch disease. These days, Kazakhstan, increased trade and investment with Korea, has been on the rise as new supplier for energy. Therefore, economic change in Kazakhstan can be an important issue. In this paper, we analyze relations among oil price, interest rate, and real exchange rate during sample period from January 1999 to December 2008 expanding Balasa-Samuelson model. Empirical results present that oil price, interest rate, and real exchange rate mutually keep their balance. Eventually, we find out Kazakhstan has exposed at Dutch disease since oil price and interest rate have negative impacts on real exchange rate respectively.

A Modeling for Li-Ion Battery Performance Analysis of GEO Satellite (정지궤도 인공위성 리튬-이온 배터리 성능 해석을 위한 모델링)

  • Koo, Ja-Chun;Ra, Sung-Woong
    • Journal of the Korean Society for Aeronautical & Space Sciences
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    • v.42 no.2
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    • pp.150-157
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    • 2014
  • Li-Ion battery is used in the most satellites now due to advantages such as weight, thermal dissipation and self discharge compared to the previous generations of electrochemical batteries. The performance analysis model of the Li-Ion battery is needed to aid the design of new satellite electrical power subsystem. This paper develops the performance analysis model of the Li-Ion battery to apply to the electrical power subsystem design and energy balance analysis on geostationary orbit. The analysis model receives the satellite bus power, solar array power and battery temperature and gives the battery voltage, charge and discharge currents, taper index, state of charge and power dissipation. The results from the performance analysis are compared and analyzed with the flight data to verify the model. The compared results show satisfactory without significant difference with the flight data.

Evaluation of JULES Land Surface Model Based on In-Situ Data of NIMS Flux Sites (국립기상과학원 플럭스 관측 자료 기반의 JULES 지면 모델 모의 성능 분석)

  • Kim, Hyeri;Hong, Je-Woo;Lim, Yoon-Jin;Hong, Jinkyu;Shin, Seung-Sook;Kim, Yun-Jae
    • Atmosphere
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    • v.29 no.4
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    • pp.355-365
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    • 2019
  • Based on in-situ monitoring data produced by National Institute of Meteorological Sciences, we evaluated the performance of Joint UK Land Environment Simulator (JULES) on the surface energy balance for rice-paddy and cropland in Korea with the operational ancillary data used for Unified Model (UM) Local Data Assimilation and Prediction System (LDAPS) (CTL) and the high-resolution ancillary data from external sources (EXP). For these experiments, we employed the one-year (March 2015~February 2016) observations of eddy-covariance fluxes and soil moisture contents from a double-cropping rice-paddy in BoSeong and a cropland in AnDong. On the rice-paddy site the model performed better in the CTL experiment except for the sensible heat flux, and the latent heat flux was underestimated in both of experiments which can be inferred that the model represents flood-irrigated surface poorly. On the cropland site the model performance of the EXP experiment was worse than that of CTL experiment related to unrealistic surface type fractions. The pattern of the modeled soil moisture was similar to the observation but more variable in time. Our results shed a light on that 1) the improvement of land scheme for the flood-irrigated rice-paddy and 2) the construction of appropriate high-resolution ancillary data should be considered in the future research.

Stress-Strain Responses of Concrete Confined by FRP Composites (FRP 합성재료에 의하여 구속된 콘크리트의 응력-변형률 응답 예측)

  • Cho, Soon-Ho
    • Journal of the Korea Concrete Institute
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    • v.19 no.6
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    • pp.803-810
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    • 2007
  • An analytical method capable of predicting various stress-strain responses in axially loaded concrete confined with FRP (fiber reinforced polymers) composites in a rational manner is presented. Its underlying idea is that the volumetric expansion due to progressive microcracking in mechanically loaded concrete is an important measure of the extent of damage in the material microstructure, and can be utilized to estimate the load-carrying capacity of concrete by considering the corresponding accumulated damage. Following from this, an elastic modulus expressed as a function of area strain and concrete porosity, the energy-balance equation relating the dilating concrete to the confining device interactively, the varying confining pressure, and an incremental calculation algorithm are included in the solution procedure. The proposed method enables the evaluation of lateral strains consecutively according to the related mechanical model and the energy-balance equation, rather than using an empirically derived equation for Poisson's ratio or dilation rate as in other analytical methods. Several existing analytical methods that can predict the overall response were also examined and discussed, particularly focusing on the way of considering the volumetric expansion. The results predicted by the proposed and Samaan's bilinear equation models correlated with observed results with a reasonable degree, however it can be judged that the latter is not capable of predicting the response of lateral strains correctly due to incorporating the initial Poisson's ratio and the final converged dilation rate only. Further, the proposed method seems to have greater benefits in other applications by the use of the fundamental principles of mechanics.

Characteristics of Greenup and Senescence for Evapotranspiration in Gyeongan Watershed Using Landsat Imagery (Landsat 인공위성 이미지를 이용한 경안천 유역 증발산의 생장기와 휴면기 분포 특성 분석)

  • Choi, Minha;Hwang, Kyotaek;Kim, Tae-Woong
    • KSCE Journal of Civil and Environmental Engineering Research
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    • v.31 no.1B
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    • pp.29-36
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    • 2011
  • Evapotranspiration (ET) from the various surfaces needs to be understood because it is a crucial hydrological factor to grasp interaction between the land surface and the atmosphere. A traditional way of estimating it, which is calculating it empirically using lysimeter and pan evaporation observations, has a limitation that the measurements represent only point values. However, these measurements cannot describe ET because it is easily affected by outer circumstances. Thus, remote sensing technology was applied to estimate spatial distribution of ET. In this study, we estimated major components of energy balance method (i.e. net radiation flux, soil heat flux, sensible heat flux, and latent heat flux) and ET as a map using Mapping Evapo-Transpiration with Internalized Calibration (METRIC) satellite-based image processing model. This model was run using Landsat imagery of Gyeongan watershed in Korea on Feb 1, 2003 and Sep 13, 2006. Basic statistical analyses were also conducted. The estimated mean daily ETs had respectively 22% and 11% of errors with pan evaporation data acquired from the Suwon Weather Station. This result represented similar distribution compared with previous studies and confirmed that the METRIC algorithm had high reliability in the watershed. In addition, ET distribution of each land use type was separately examined. As a result, it was identified that vegetation density had dominant impacts on distribution of ET. Seasonally, ET in a growing season represented significantly higher than in a dormant season due to more active transpiration. The ET maps will be useful to analyze how ET behaves along with the circumstantial conditions; land cover classification, vegetation density, elevation, topography.

The Effect of Wind (Typhoon), Tide and Solar Radiation for the Water Stratification at Deukryang Bay in Summer , 1992 (하계 득량만의 연직혼합과 관련된 바람 (태풍), 조석, 태양에너지의 영향)

  • Lee, Byung-Gul;Cho, Kyu-Dae;Hong, Chol-Hoon
    • Journal of the Korean Society of Fisheries and Ocean Technology
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    • v.31 no.3
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    • pp.256-263
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    • 1995
  • This paper presents the evidence on the considerably strong stratification - destratification(SD) phenomena during spring - neap tidal cycle in summer of 1992 based on the observed temperature, salinity and density data. To find out the main factors causing SD in the bay, we computed the rate of potential energy balance of the surface heat flux, tidal and wind stirring proposed by Simpson and Hunter (1974) and Simpson and Bowders (1981) using observed data. It was found that the energy of the wind stirring was one - order smaller than those of the heat flux and the tidal stirring. It means that the variation of stratification phenomena in the bay mainly depend on tidal stirring and sea surface heating in summer if there was no exceptionally strong wind event like a typhoon. Finally, we tested the effects of typhoon on the mixing characteristics of the bay using the example of a empirical typhoon model. It was found that when wind speed is larger than 15m/sec in Deukryang Bay, the wind energy was always larger than the average heating energy based on empirical typhoon model test. Particularly, typhoon passed on the left side of the bay, strong wind energy happened, which is almost the same as tidal energy of spring tide.

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Response Reduction of a SDOF Structure based on Friction Force Ratio of MR Controller (MR제어기의 마찰력비에 따른 단자유도 구조물의 응답감소)

  • Seong, Ji-Young;Min, Kyung-Won
    • Journal of the Computational Structural Engineering Institute of Korea
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    • v.23 no.4
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    • pp.435-443
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    • 2010
  • This study presents key parameters for the structure installed with MR controller in reducing its responses. MR controller is regarded as Bingham model of which control forces are frictional and viscous ones. The parameters are identified as friction force ratios, $R_f$ and $R_h$ which are, respectively, ratio of MR controller friction force to static restoring force for free vibration and ratio of the friction force to amplitude of harmonic force. Structure-MR controller system shows nonlinear response behavior due to friction force. Energy balance strategy is adopted to transform the behavior to linear one with equivalent damping ratio. Finally, proposed equivalent linear process is compared to the nonlinear one, which turns out to give acceptably good results.

Probing α/β Balances in Modified Amber Force Fields from a Molecular Dynamics Study on a ββα Model Protein (1FSD)

  • Yang, Changwon;Kim, Eunae;Pak, Youngshang
    • Bulletin of the Korean Chemical Society
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    • v.35 no.6
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    • pp.1713-1719
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    • 2014
  • 1FSD is a 28-residue designed protein with a ${\beta}{\beta}{\alpha}$ motif. Since this protein displays most essential features of protein structures in such a small size, this model protein can be an outstanding system for evaluating the balance in the propensity of the secondary structures and the quality of all-atom protein force fields. Particularly, this protein would be difficult to fold to its correct native structure without establishing proper balances between the secondary structure elements in all-atom energy functions. In this work, a series of the recently optimized five amber protein force fields [$ff03^*$, $f99sb^*$-ildn, ff99sb-${\phi}^{\prime}$-ildn, ff99sb-nmr1-ildn, ff99sb-${\Phi}{\Psi}$(G24, CS)-ildn] were investigated for the simulations of 1FSD using a conventional molecular dynamics (MD) and a biased-exchange meta-dynamics (BEMD) methods. Among those tested force fields, we found that ff99sb-nmr1-ildn and ff99sb-${\Phi}{\Psi}$(G24, CS)-ildn are promising in that both force fields can locate the native state of 1FSD with a high accuracy (backbone rmsd ${\leq}1.7{\AA}$) in the global free energy minimum basin with a reasonable energetics conforming to a previous circular dichroism (CD) experiment. Furthermore, both force fields led to a common set of two distinct folding pathways with a heterogeneous nature of the transition state to the folding. We anticipate that these force fields are reasonably well balanced, thereby transferable to many other protein folds.

Analysis of the Hydraulic Behaviour in the Nearshore Zone by a Numerical Model (수치모형에 의한 연안해역 해수운동의 분석)

  • Lee, Hee-Young;Jeoung, Sun-Kil
    • Water for future
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    • v.27 no.2
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    • pp.73-83
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    • 1994
  • The unproper development of the nearshore zone can enhance the diffusion of pollutant in the nearshore zone resulting in unbalanced sediment budget of beach which causes alteration of beach topography. Therefore, it is required to predict the effects of the envirnmental change quantitatively. In this paper, the depth-averaged and time-averaged energy balance equation is selected to acount for the wave transformation such as refraction, shoaling effect, the surf zone energy disipation, wave breaking index and bore, due to wave breaking in the shore region.(Numerical solutions are obtained by a finite difference method, ADI and Upwind. For the calculation of the wave-induced current, the unsteady nonlinear depth-averaged and time-averaged governing equation is derived based on the continuity and momentum equation for imcompressible fluid.) Numerical solutions are obtained by finite difference method considering influences of factors such as lateral mixing coefficient, bed shear stress, wave direction angle, wave steepness, wave period and bottom slope. The model is applied to the computation of wave transformation, wave-induced current and variation of mean water leel on a uniformly sloping beach.

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Receptor Model(CMB) and Source Apportionments of VOCs in Seoul Metropolitan Area (수용모델(CMB)을 이용한 수도권 VOCs의 배출원별 기여율 추정)

  • Han, Jin-Seok;Hong, Y.D.;Shin, S.A.;Lee, S.U.;Lee, S.J.
    • Journal of Environmental Impact Assessment
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    • v.14 no.4
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    • pp.227-235
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    • 2005
  • Source contribution for VOCs collected in Seoul metropolitan area was conducted using PAMs (Photochemical assessment monitoring system) data and CMB(Chemical Mass Balance) model8.0, in order to estimate spatial and temporal variations of VOCs source contribution in that area, and also to compare with corresponding emission inventory. VOCs data used in model calculation were collected at 6 different sites of PAMs(Seokmori, Guwoldong, Simgokdong, Bulgwangdong, Jeongdong and Yangpyeong) and 22 out of 56 VOCs species were analyzed from June 2002 to march 2003 and used for CMB model estimation. The result showed that vehicle exhaust, coating and energy combustion were important sources of VOCs in Seoul metropolitan area, averaging 32.6%, 25.5% and 25.1%, respectively. In this study as well as other references, it was revealed that vehicle exhaust is the main contributor of urban area VOCs, but there is remarkable contrast between emission inventory and model estimation. Vehicle exhaust portion is seriously underestimated while coating is usually overestimated in emission estimates, compared to CMB results. Therefore, it is considered to assert and confirm the uncertainty of emission estimates and clarify the distinction between two other source apportionment methods.