• Proceedings of the Korea Water Resources Association Conference
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• 2004.05b
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• pp.272-276
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• 2004

이수기와 같이 장기적인 관점에서 저수지운영을 해야 하는 관리자는 해당 기간동안의 이익을 최대화하는 전략을 필요로 한다. 이를 위해서는 미래 유입량의 불확실성을 고려한 최적화 모형에 근거한 운영률을 수립해야 할 것이다. 본 연구에서는 금강수계의 이수기를 대상으로 추계학적 최적화 기법인 표본 추계학적 동적계획법(Sampling Stochastic Dynamic Programming)을 적용하여 최적 연계운영 시스템을 개발하였다. 본 연구를 통해 개발된 모형은 상용프로그램인 CSUDP와의 비교를 통해 검증되었으며 이를 기반으로 과거자료를 이용한 SSDP/Hist모형과 앙상블 유량예측(Ensemble Streamflow Prediction)을 이용한 SSDP/ESP모형을 개발하여 두 모형의 장${\cdot}$단점을 비교 분석하였다. 발전부분은 두 모형이 비슷하였으나 용수공급 측면에서는 SSDP/ESP가 SSDP/Hist 보다 우수함을 알 수 있었다.

• Proceedings of the Korea Water Resources Association Conference
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• 2007.05a
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• pp.311-315
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• 2007

본 연구에서는 칼만필터(Kalman filter) 개념을 도입한 추계학적 편차보정 기법을 활용하여 실시간으로 레이더 및 관측강우에 대한 불확실성을 줄일 수 있는 레이더 최적강수 산정기법 개발에 관한 연구를 수행하였다. 개발된 레이더 강우량 추정기법은 한강유역을 대상으로 적용되었으며, 여기서 사용된 레이더 자료는 기상청에서 수집한 레이더 합성 CAPPI(Constant Altitude Plan Position Indicator) 자료이다. 자료기간은 2004년 7월 및 2006년 7월의 각 한달치 10분 간격의 레이더 자료가 사용되었고, 본 기간에 대응하는 약 130여개 지점의 기상청 AWS(Automatic Weather Station) 강우 관측자료가 편차보정을 위해 사용되었다. 매개변수별 편차추정 분석을 수행한 결과, 한강유역의 주어진 자료기간에 대한 적절한 편차추정을 위해 N=10, $i_T=2mm/h$의 매개변수를 선정하여 레이더 강수추정 오차에 대한 편차를 계산하여 개발 보정기법을 적용하였다. 그 결과 본 연구에서 개발한 추계동역학적 편차보정 기법은 Marshall-Palmer 기법의 높은 편차를 1에 가깝게 줄일 수 있는 것으로 나타났고, 홍수기 급박한 재해상황에서 보다 신속히 레이더 강수장을 제공할 수 있는 현업적 보정기법으로써의 유용성이 매우 높은 것으로 평가되었다.

• Computational Structural Engineering
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• v.8 no.1
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• pp.127-136
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• 1995

In this paper the stochastic FE analysis considering the material and geometrical property of the plate structure is performed by the weighted integral method. To consider the stochasity of the material and geometrical property, the stochastic field is assumed respectively. The mean value of the stochastic field is 0 and the value of variance is assumed as 0.1. The characteristics of the assumed stochastic field is represented by auto-correlation function. This auto-correlation function is used in evaluating the response variability of the plate structure. In this study a new auto-correlation function is derived to concern the uncertainty of the plate thickness. The newly derived auto-correlation function is a function of auto-correlation function and coefficient of variation of the assumed stochastic field. The two results, obtained by proposed Weighted Integral method and Monte Carlo Simulation method, are coincided with each other and these results are almost equal to the theoretical result that is derived in this study. In the case of considering the variability of plate thickness, the obtained result is well coincide with those of Lawrence and Monte Carlo simulation.

• The Korean Journal of Applied Statistics
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• v.33 no.2
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• pp.185-201
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• 2020

Scenario population projection reflects the high probability of future realization and ease of statistical interpretation. Statistics Korea (2019) also presents the results of 30 combinations, including special scenarios, as official statistics. However, deterministic population projections provide limited information about future uncertainties with several limitations that are not probabilistic. The deterministic population projections are scenario-based estimates and show a perfect autocorrelation of three factors (birth, death, movement) of population variation over time. Therefore, international organizations UN, the Max Planck Population Research Institute (MPIDR) of Germany and the Vienna Population Research Institute (VID) of Austria have suggested stochastic based population estimates. In addition, some National Statistics Offices have also adopted this method to provide information along with the scenario results. This paper calculates the demographics of Korea based on a probabilistic or stochastic basis and then draws the pros and cons and show implications of the scenario (deterministic) population projections.

• Proceedings of the Korea Water Resources Association Conference
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• 2005.05b
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• pp.225-229
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• 2005

이류모형을 이용한 단기예측 레이더 강우자료와 관측 레이더자료의 비교를 통하여 얻어진 예측오차를 분석하였다. 임의 시점까지의 예측오차 장에 나타나는 확률분포 형태와 공간적 상관성을 분석하여 이들 특성을 반영하는 추후의 예측오차 장을 모의할 수 있었다. 모의된 예측오차 장과 합성된 단기예측 강우 장은 이류모형을 이용한 예측에 따른 불확실성 을 추계학적으로 반영한 예측강우를 제공한다.

• Survey Research
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• v.11 no.2
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• pp.71-95
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• 2010

Base population, intercensal and postcensal population estimates, and population projections have been regularly published as official populations. Base population is usually made out based on census conducted every 5 or 10 years, and is most important from which intercensal, postcensal estimates, and population projections are derived. We investigate how base population in Korea is made out and then compare it with those of other countries. We also present problems arising from making out base population in Korea.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.13 no.1
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• pp.147-158
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• 2000

For the large scale reinforced concrete cooling tower shells, the shape imperfection can be introduced due not only to mistakes in the process of construction but also to the long term behavior of concrete. The shape imperfection evokes the additional responses such as displacements and stresses in addition to the design values. In this study, the statistical behavior of the RC cooling tower shell due to the shape imperfection is investigated using the Monte Carlo simulation. The radius of cooling tower and the shell thickness are adopted as the parameters which cause the shape imperfection. The shape imperfection is modeled as a stochastic field rather than the local one of axisymmetric or bulge type of imperfection. The randomness in the radius is shown to be more affecting the structural responses than the randomness in the shell thickness. In addition to the geometrical randomness, the effect of randomness in the modulus of elasticity on the structural response is also investigated and compared with that of the geometrical ones.

• Journal of the Korean earth science society
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• v.23 no.7
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• pp.617-617
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• 2002

• Journal of the Korean hospital association
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• v.20 no.4 s.183
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• pp.16-28
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• 1991

• Journal of the Korean Society of Marine Environment & Safety
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• v.25 no.1
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• pp.58-66
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• 2019

Paralarvae of the common squid, Todarodes pacificus, were sampled with the bongo net (diameter: 60 cm, mesh: $333{\mu}m$) with a research vessel (Tamgu 20) at 18 stations along the coastal waters of the Yellow Sea in spring and autumn from 2013 to 2015. Over this period, 4 Paralarvae were collected. Paralarval density was $0.1inds./1,000m^3$ and $0.2inds./1,000m^3$ in autumn 2014 and $0.1inds./1,000m^3$ and $0.2inds./1,000m^3$ in autumn 2015. The range of mantle length for paralarvae was from 1.5 to 8.3 mm. Survival temperature ($15-24^{\circ}C$) for embryo stage and paralarvae was found in locations shallower than 56 m of depth at stations which were sampled for paralarvae.