• Title/Summary/Keyword: confidence probability

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Probabilistic Prediction and Field Measurement of Column Shortening for Tall Building with Bearing Wall System (초고층 내력벽식 구조물의 기둥축소량에 대한 확률론적 예측 및 현장계측)

  • Song, Hwa-Cheol;Yoon, Kwang-Sup
    • Journal of the Korea Concrete Institute
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    • v.18 no.1 s.91
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    • pp.101-108
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    • 2006
  • Accurate prediction of time-dependent column shortening is essential for tall buildings in both strength and serviceability aspects. The uncertainty associated with assumed values for concrete properties such as strength, creep, and shrinkage coefficients should be considered for the prediction of time-dependent column shortening of tall concrete buildings. In this study, the column shortenings of 41-story tall concrete building are predicted using monte carlo simulation technique based on the probabilistic analysis. The probabilistic column shortenings considering confidence intervals are compared with the actual column shortenings by field measurement. The time-dependent strains measured at tall bearing wall building were generally lower than the predicted strains and the measured values fell within a range ${\mu}-1.64$, confidence level 90%.

CONSTRAINING COSMOLOGICAL PARAMETERS WITH IMAGE SEPARATION STATISTICS OF GRAVITATIONALLY LENSED SDSS QUASARS: MEAN IMAGE SEPARATION AND LIKELIHOOD INCORPORATING LENS GALAXY BRIGHTNESS

  • Han, Du-Hwan;Park, Myeong-Gu
    • Journal of The Korean Astronomical Society
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    • v.48 no.1
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    • pp.83-92
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    • 2015
  • Recent large scale surveys such as Sloan Digital Sky Survey have produced homogeneous samples of multiple-image gravitationally lensed quasars with well-defined selection effects. Statistical analysis on these can yield independent constraints on cosmological parameters. Here we use the image separation statistics of lensed quasars from Sloan Digital Sky Survey Quasar Lens Search (SQLS) to derive constraints on cosmological parameters. Our analysis does not require knowledge of the magnification bias, which can only be estimated from the detailed knowledge on the quasar luminosity function at all redshifts, and includes the consideration for the bias against small image separation quasars due to selection against faint lens galaxy in the follow-up observations for confirmation. We first use the mean image separation of the lensed quasars as a function of redshift to find that cosmological models with extreme curvature are inconsistent with observed lensed quasars. We then apply the maximum likelihood test to the statistical sample of 16 lensed quasars that have both measured redshift and magnitude of lens galaxy. The likelihood incorporates the probability that the observed image separation is realized given the luminosity of the lens galaxy in the same manner as Im et al. (1997). We find that the 95% confidence range for the cosmological constant (i.e., the vacuum energy density) is $0.72{\leq}{\Omega}_{\Lambda}{\leq}1.0$ for a flat universe. We also find that the equation of state parameter can be consistent with -1 as long as the matter density ${\Omega}_m{\leq}0.4$ (95% confidence range). We conclude that the image separation statistics incorporating the brightness of lens galaxies can provide robust constraints on the cosmological parameters.

Seismic Performance Evaluation of a RC Special Moment Frame Building (철근 콘크리트 특수 모멘트 골조 건물의 내진 성능 평가)

  • Kim, Tae-Wan;Kim, Jin-Koo
    • Journal of the Earthquake Engineering Society of Korea
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    • v.11 no.2 s.54
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    • pp.39-45
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    • 2007
  • In this study the probability and the reliability-based seismic performance evaluation procedure proposed in the FEMA-355F was applied to a reinforced concrete moment frame building. For the FEMA procedure, which was originally developed for steel moment frame structures, to be applied to other structural systems, the capacity should be re-defined and the factors reflecting the uncertainties related to capacity and demand need to be determined. To perform the evaluation procedure a prototype building was designed per IBC 2003, and inelastic dynamic analyses were conducted applying site-specific ground motions to determine the parameters for performance evaluation. According to the analysis results, distribution of the determined capacities turned out to be relative]y smaller than that of the demands, which showed that the defined capacity was reasonable. It was also shown that the prototype building satisfied the target performance since the determined confidence levels exceeded the otjectives for both local and global collapses.

Estimation of Design Flood by the Determination of Best Fitting Order of LH-Moments(II) (LH-모멘트의 적정 차수 결정에 의한 설계홍수량 추정(II))

  • 맹승진;이순혁
    • Magazine of the Korean Society of Agricultural Engineers
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    • v.45 no.1
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    • pp.33-44
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    • 2003
  • This study was conducted to estimate the design flood by the determination of best fitting order for LH-moments of the annual maximum series at fifteen watersheds. Using the LH-moment ratios and Kolmogorov-Smirnov test, the optimal regional probability distribution was identified to be the Generalized Extreme Value (GEV) in the first report of this project. Parameters of GEV distribution and flood flows of return period n years were derived by the methods of L, L1, L2, L3 and L4-moments. Frequency analysis of flood flow data generated by Monte Carlo simulation was performed by the methods of L, L1, L2, L3 and L4-moments using GEV distribution. Relative Root Mean Square Error. (RRMSE), Relative Bias (RBIAS) and Relative Efficiency (RE.) using methods of L, Ll , L2, L3 and L4-moments for GEV distribution were computed and compared with those resulting from Monte Carlo simulation. At almost all of the watersheds, the more the order of LH-moments and the return periods increased, the more RE became, while the less RRMSE and RBIAS became. The Absolute Relative Reduction (ARR) for the design flood was computed. The more the order of LH-moments increased, the less ARR of all applied watershed became It was confirmed that confidence efficiency of estimated design flood was increased as the order of LH-moments increased. Consequently, design floods for the appled watersheds were derived by the methods of L3 and L4-moments among LH-moments in view of high confidence efficiency.

Integrated Watershed Modeling Under Uncertainty (불확실성을 고려한 통합유역모델링)

  • Ham, Jong-Hwa;Yoon, Chun-Gyoung;Loucks, Daniel P.
    • Journal of The Korean Society of Agricultural Engineers
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    • v.49 no.4
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    • pp.13-22
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    • 2007
  • The uncertainty in water quality model predictions is inevitably high due to natural stochasticity, model uncertainty, and parameter uncertainty. An integrated modeling system under uncertainty was described and demonstrated for use in watershed management and receiving-water quality prediction. A watershed model (HSPF), a receiving water quality model (WASP), and a wetland model (NPS-WET) were incorporated into an integrated modeling system (modified-BASINS) and applied to the Hwaseong Reservoir watershed. Reservoir water quality was predicted using the calibrated integrated modeling system, and the deterministic integrated modeling output was useful for estimating mean water quality given future watershed conditions and assessing the spatial distribution of pollutant loads. A Monte Carlo simulation was used to investigate the effect of various uncertainties on output prediction. Without pollution control measures in the watershed, the concentrations of total nitrogen (T-N) and total phosphorous (T-P) in the Hwaseong Reservoir, considering uncertainty, would be less than about 4.8 and 0.26 mg 4.8 and 0.26 mg $L^{-1}$, respectively, with 95% confidence. The effects of two watershed management practices, a wastewater treatment plant (WWTP) and a constructed wetland (WETLAND), were evaluated. The combined scenario (WWTP + WETLAND) was the most effective at improving reservoir water quality, bringing concentrations of T-N and T-P in the Hwaseong Reservoir to less than 3.54 and 0.15 mg ${L^{-1}$, 26.7 and 42.9% improvements, respectively, with 95% confidence. Overall, the Monte Carlo simulation in the integrated modeling system was practical for estimating uncertainty and reliable in water quality prediction. The approach described here may allow decisions to be made based on probability and level of risk, and its application is recommended.

A-priori Comparative Assessment of the Performance of Adjustment Models for Estimation of the Surface Parameters against Modeling Factors (표면 파라미터 계산시 모델링 인자에 따른 조정계산 추정 성능의 사전 비교분석)

  • Seo, Su-Young
    • Spatial Information Research
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    • v.19 no.2
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    • pp.29-36
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    • 2011
  • This study performed quantitative assessment of the performance of adjustment models by a-priori analysis of the statistics of the surface parameter estimates against modeling factors. Lidar, airborne imagery, and SAR imagery have been used to acquire the earth surface elevation, where the shape properties of the surface need to be determined through neighboring observations around target location. In this study, parameters which are selected to be estimated are elevation, slope, second order coefficient. In this study, several factors which are needed to be specified to compose adjustment models are classified into three types: mathematical functions, kernel sizes, and weighting types. Accordingly, a-priori standard deviations of the parameters are computed for varying adjustment models. Then their corresponding confidence regions for both the standard deviation of the estimate and the estimate itself are calculated in association with probability distributions. Thereafter, the resulting confidence regions are compared to each other against the factors constituting the adjustment models and the quantitative performance of adjustment models are ascertained.

Use of a Bootstrap Method for Estimating Basic Wood Density for Pinus densiflora in Korea (부트스트랩을 이용한 소나무의 목재기본밀도 추정 및 평가)

  • Pyo, Jung Kee;Son, Yeong Mo;Kim, Yeong Hwan;Kim, Rae Hyun;Lee, Kyeong Hak;Lee, Young Jin
    • Journal of Korean Society of Forest Science
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    • v.100 no.3
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    • pp.392-396
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    • 2011
  • The purpose of this study was to develop the basic wood density (Abbreviated BWD) for Pinus densiflora and to evaluate the applicability of bootstrap simulation method. The data sets were divided into two groups based on eco-types in Korea, one from Gangwon type and the other from Jungbu type. The estimated BWDs derived from bootstrap simulation, which is one of the non-parametric statistics, were 0.418 ($g/cm^3$) in the Pinus densiflora in Gangwon while 0.464 ($g/cm^3$) in the Pinus densiflora in Jungbu. To evaluate the bootstrap simulation, the mean BWD, standard error and 95% confidence interval of probability density were estimated. The number of replication were 100, 500, 1,000, and 5,000 times that showed constant 95% confidence interval, while tended to decrease in terms of standard errors. The results of this study could be very useful to apply basic wood density values to calculate reliable carbon stocks for Pinus densiflora in Korea.

Construction of a Nomogram for Predicting Difficulty in Peripheral Intravenous Cannulation (말초 정맥주사 삽입 어려움 예측을 위한 노모그램 구축)

  • Kim, Kyeong Sug;Choi, Su Jung;Jang, Su Mi;Ahn, Hyun Ju;Na, Eun Hee;Lee, Mi Kyoung
    • Journal of Korean Academic Society of Home Health Care Nursing
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    • v.30 no.1
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    • pp.48-58
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    • 2023
  • Purpose: The purpose of this study was to construct a nomogram for predicting difficulty in peripheral intravenous cannulation (DPIVC) for adult inpatients. Methods: This study conducted a secondary analysis of data from the intravenous cannulation cohort by intravenous specialist nurses at a tertiary hospital in Seoul. Overall, 504 patients were included; of these, 166 (32.9%) patients with failed cannulation in the first intravenous cannulation attempt were included in the case group, while the remaining 338 patients were included in the control group. The nomogram was built with the identified risk factors using a multiple logistic regression analysis. The model performance was analyzed using the Hosmer-Lemeshow test, area under the curve (AUC), and calibration plot. Results: Five factors, including vein diameter, vein visibility, chronic kidney disease, diabetes, and chemotherapy, were risk factors of DPIVC. The nomogram showed good discrimination with an AUC of 0.81 (95% confidence interval: 0.80-0.82) by the sample data and 0.79 (95% confidence interval: 0.74-0.84) by bootstrapping validation. The Hosmer-Lemeshow goodness-of-fit test showed a p-value of 0.694, and the calibration curve of the nomogram showed high coherence between the predicted and actual probabilities of DPIVC. Conclusion: This nomogram can be used in clinical practice by nurses to predict DPIVC probability. Future studies are required, including those on factors possibly affecting intravenous cannulation.

Statistical Characteristics and Stochastic Modeling of Water Quality Data at the Influent of Daejeon Wastewater Treatment Plant (대전시 공공하수처리시설 유입수 수질자료의 통계적 특성 및 추계학적 모의)

  • Pak, Gijung;Jung, Minjae;Lee, Hansaem;Kim, Deokwoo;Yoon, Jaeyong;Paik, Kyungrock
    • Journal of Korean Society on Water Environment
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    • v.28 no.1
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    • pp.38-49
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    • 2012
  • In this study, we analyze statistical characteristics of influent water quality in Daejeon waste water treatment plant and apply a stochastic model for data generation. In the analysis, the influent water quality data from year 2003 to 2008, except for year 2006, are used. Among water quality variables, we find strong correlations between BOD and T-N; T-N and T-P; BOD and T-P; $COD_{Mn}$ and T-P; and BOD and $COD_{Mn}$. We also find that different water quality variables follow different theoretical probability distribution functions, which also depends on whether the seasonal cycle is removed. Finally, we generate the influent water quality data using the multi-season 1st Markov model (Thomas-Fiering model). With model parameters calibrated for the period 2003~2005, the generated data for 2007~2008 are well compared with observed data showing good agreement in general. BOD and T-N are underestimated by the stochastic model. This is mainly due to the statistical difference in observed data itself between two periods of 2003~2005 and 2007~2008. Therefore, we expect the stochastic model can be applied with more confidence in the case that the data follows stationary pattern.

Characteristics on the Extreme Value Distributions of Deepwater Design ave Heights off the Korean Coast (한국 연안 심해 설계파고의 극치분포 특성)

  • Shin Taek Jeong;Jeong Dae Kim;Cho Hong Yeon
    • Journal of Korean Society of Coastal and Ocean Engineers
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    • v.16 no.3
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    • pp.130-141
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    • 2004
  • For a coastal or harbor structure design, one of the most important environmental factors is the appropriate design wave condition. Especially, the information of deepwater wave height distribution is essential for reliability design. In this paper, a set of deep water wave data obtained from KORDI(2003) were analyzed for extreme wave heights. These wave data at 67 stations off the Korean coast from 1979 to 1998 were arranged in the 16 directions. The probability distributions considered in this research were the Weibull, the Gumbel, the Log-pearson Type-III, and Lognormal distribution. For each of these distributions, three parameter estimation methods, i.e. the method of moments, maximum likelihood and probability weighted moments, were applied. Chi-square and Kolmogorov-Smirnov goodness-of-fit tests were performed, and the assumed distribution was accepted at the confidence level 95%. Gumbel distribution which best fits to the 67 station was selected as the most probable parent distribution, and optimally estimated parameters and 50 year design wave heights were presented.