• Title/Summary/Keyword: confidence bands

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The Confidence Bands for the Survival Function in Random Censorship Model (임의중도절단된 자료에서 생존함수의 동시신뢰대 구성)

  • Lee, Won-Kee;Song, Myung-Unn;Song, Jae-Kee;Park, Hee-Joo
    • Journal of the Korean Data and Information Science Society
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    • v.9 no.1
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    • pp.37-45
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    • 1998
  • We consider the problem of obtaining the confidence bands for the survival function with incomplete data. It is a rather simple procedure for constructing confidence bands of survival function. This method uses the weak convergence of normalized cumulative hazard estimator to a mean zero Gaussian process whose distribution can be easily approximated through simulation. Finally, we compare the performance of the proposed confidence bands through Monte Carlo simulation and we applied to construct the proposed bands with the Leukemia patient data.

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Confidence bands for survival curve under the additive risk model

  • Song, Myung-Unn;Jeong, Dong-Myung;Song, Jae-Kee
    • Journal of the Korean Statistical Society
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    • v.26 no.4
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    • pp.429-443
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    • 1997
  • We consider the problem of obtaining several types of simultaneous confidence bands for the survival curve under the additive risk model. The derivation uses the weak convergence of normalized cumulative hazard estimator to a mean zero Gaussian process whose distribution can be easily approxomated through simulation. The bands are illustrated by applying them from two well-known clinicla studies. Finally, simulation studies are carried outo to compare the performance of the proposed bands for the survival function under the additive risk model.

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Bootstrapped Confidence Bands for Quantile Function under LTRC Model

  • Cho, Kil-Ho;Chae, Hyeon-Sook;Choi, Dal-Woo
    • Journal of the Korean Data and Information Science Society
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    • v.8 no.1
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    • pp.49-58
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    • 1997
  • We consider the quantile function for the bootstrapped product limit estimate under left truncation and right censoring model and show its weak convergence. We also obtain bootstrapped confidence bands for the quantile function.

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The Confidence Band of $ED_{100p}$ for the Simple Logistic Regression Model

  • Cho, Tae Kyoung;Shin, Mi Young
    • Communications for Statistical Applications and Methods
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    • v.8 no.3
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    • pp.581-588
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    • 2001
  • The $ED_{100p}$ is that value of the dose associated with 100p% response rate in the analysis of quantal response data. Brand, Pinnock, and Jackson (1973) studied the confidence bands of $ED_{100p}$ obtained by solving extremal values algebraically on the ellipsoid confidence region of the parameters in the simple logistic regression model. In this paper, we develope and illustrate a simpler method for obtaining confidence bands for $ED_{100p}$ based on the rectangular confidence region of parameters.

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Analyzing Survival Data by Proportional Reversed Hazard Model

  • Gupta, Ramesh C.;Wu, Han
    • International Journal of Reliability and Applications
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    • v.2 no.1
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    • pp.1-26
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    • 2001
  • The purpose of this paper is to introduce a proportional reversed hazard rate model, in contrast to the celebrated proportional hazard model, and study some of its structural properties. Some criteria of ageing are presented and the inheritance of the ageing notions (of the base line distribution) by the proposed model are studied. Two important data sets are analyzed: one uncensored and the other having some censored observations. In both cases, the confidence bands for the failure rate and survival function are investigated. In one case the failure rate is bathtub shaped and in the other it is upside bath tub shaped and thus the failure rates are non-monotonic even though the baseline failure rate is monotonic. In addition, the estimates of the turning points of the failure rates are provided.

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Confidence Bands for Survival Function Based on Hjort Estimator

  • Byung-Gu Park;Kil-Ho Cho;Woo-Dong Lee;Young-Joon Cha
    • Communications for Statistical Applications and Methods
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    • v.3 no.2
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    • pp.119-127
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    • 1996
  • In this paper, we derive the Hall-Wellner band and the equal precistion band for survival function based on Hjort when the data are randomly right censored. The bands ate illustrated and compared by applying them to data from a preoperative radiation therapy.

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OPTICAL INVESTIGATION OF THE CRAB PULSAR: SIMULTANEOUS UBVR LIGHT CURVES WITH TIME RESOLUTION OF 3.3 ${\mu}s$ AND SPECTROSCOPY

  • KOMAROVA V. N.;BESKIN G. M.;NEUSTROEV V. V.;PLOKHOTNICHENKO V. L.
    • Journal of The Korean Astronomical Society
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    • v.29 no.spc1
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    • pp.217-218
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    • 1996
  • The results of the Crab pulsar observations with the photometrical MANIA (Multichannel Analysis of Nanosecond Intensity Alterations) complex at the 6-m telescope are presented. More than 12 millions photons in UBVR-bands simultaneously with time resolution of $10^{-7}s$ were detected. Using the original software for search for optical pulsar period, we obtained the light curves of the object with time resolution of about 3.3 ${\mu}s$. Their detailed analysis gives the spectral change during pulse and subpulse, the shape of the pulse peaks, which are plateaus (with the duration of about 50${\mu}s$ for the main pulse), limits for an amplitude of fine temporal (stochastic and regular) structure of pulse and sub pulse and the interpulse space intensity. The results of CCD-spectroscopy of the Crab pulsar show that its summarized spectrum is flat. There are no lines, neither emission nor absorbtion ones. Upper limit for line intensity or depth is $3.5\%$ with the confidence probability of $95\%$.

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Evaluation of the Uncertainties in Rainfall-Runoff Model Using Meta-Gaussian Approach (Meta-Gaussian 방법을 이용한 강우-유출 모형에서의 불확실성 산정)

  • Kim, Byung-Sik;Kim, Bo-Kyung;Kwon, Hyun-Han
    • Journal of Wetlands Research
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    • v.11 no.1
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    • pp.49-64
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    • 2009
  • Rainfall-runoff models are used for efficient management, distribution, planning, and design of water resources in accordance with the process of hydrologic cycle. The models simplify the transition of rainfall to runoff as rainfall through different processes including evaporation, transpiration, interception, and infiltration. As the models simplify complex physical processes, gaps between the models and actual rainfall events exist. For more accurate simulation, appropriate models that suit analysis goals are selected and reliable long-term hydrological data are collected. However, uncertainty is inherent in models. It is therefore necessary to evaluate reliability of simulation results from models. A number of studies have evaluated uncertainty ingrained in rainfall-runoff models. In this paper, Meta-Gaussian method proposed by Montanari and Brath(2004) was used to assess uncertainty of simulation outputs from rainfall-runoff models. The model, which estimates upper and lower bounds of the confidence interval from probabilistic distribution of a model's error, can quantify global uncertainty of hydrological models. In this paper, Meta-Gaussian method was applied to analyze uncertainty of simulated runoff outputs from $Vflo^{TM}$, a physically-based distribution model and HEC-HMS model, a conceptual lumped model.

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Automatic Cross-calibration of Multispectral Imagery with Airborne Hyperspectral Imagery Using Spectral Mixture Analysis

  • Yeji, Kim;Jaewan, Choi;Anjin, Chang;Yongil, Kim
    • Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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    • v.33 no.3
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    • pp.211-218
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    • 2015
  • The analysis of remote sensing data depends on sensor specifications that provide accurate and consistent measurements. However, it is not easy to establish confidence and consistency in data that are analyzed by different sensors using various radiometric scales. For this reason, the cross-calibration method is used to calibrate remote sensing data with reference image data. In this study, we used an airborne hyperspectral image in order to calibrate a multispectral image. We presented an automatic cross-calibration method to calibrate a multispectral image using hyperspectral data and spectral mixture analysis. The spectral characteristics of the multispectral image were adjusted by linear regression analysis. Optimal endmember sets between two images were estimated by spectral mixture analysis for the linear regression analysis, and bands of hyperspectral image were aggregated based on the spectral response function of the two images. The results were evaluated by comparing the Root Mean Square Error (RMSE), the Spectral Angle Mapper (SAM), and average percentage differences. The results of this study showed that the proposed method corrected the spectral information in the multispectral data by using hyperspectral data, and its performance was similar to the manual cross-calibration. The proposed method demonstrated the possibility of automatic cross-calibration based on spectral mixture analysis.

Effects of 8 weeks of combined forest exercise on quality of life and physical self-concept of breast cancer survivors

  • A Reum Kim;Jae Heon Son;Jun Sik Park
    • International journal of advanced smart convergence
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    • v.13 no.2
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    • pp.222-228
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    • 2024
  • The purpose of this study was to investigate the effect of 8 weeks of forestry exercise on the quality of life and physical self-concept of breast cancer survivors. The subjects of this study were eight breast cancer survivors 6 months after mastectomy. The forest combined exercise program consisted of aerobic exercise through forest walking and resistance exercise using elastic bands. The forest combined exercise was conducted twice for 8 weeks. Forest trekking consisted of a 2km walking speed and resistance exercise consisted of three levels of sets and intensity. The format was divided into gradual increases. The exercise time was 40 to 60 minutes for forest trekking, 20 to 30 minutes for descent, and 40 to 60 minutes for resistance exercise, for a total of 120 to 130 minutes per day. Breast cancer survivors' quality of life was measured using a questionnaire, and changes in quality of life were measured using a t-test (α=.05). Physical self-concept was assessed through in-depth interviews. There was no statistically significant difference in quality of life before and after 8 weeks of combined forestry exercise, but there was a slight tendency to increase in the area of physical well-being. Physical self-concept showed positive changes in motivation, physical strength improvement, health promotion, physical competence, and self-confidence through the forest composite exercise. Therefore, the forest composite exercise is believed to have a positive effect on the physical self-concept of breast cancer survivors.