• Title/Summary/Keyword: Sampling Errors

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Telephone Survey for Grasping Clinical Actual State of Bloodletting Therapeutics in Korea (국내 자락(사혈)요법 임상 실태 파악을 위한 전화조사)

  • Han, Chang-Hyun;Kim, Seon-Woong;Lee, Seung-Deok;Shin, Mi-Suk;Shin, Seon-Hwa;Choi, Sun-Mi
    • Journal of Acupuncture Research
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    • v.23 no.6
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    • pp.177-187
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    • 2006
  • Objectives : Bloodletting therapeutics is one of the most popular oriental treatments in Korea. In this study, we operate the Telephone Survey for grasping clinical actual state bloodletting therapeutics in Korea. Methods : The list of the Korean medical doctors with experiences more than 10 years is provided by the Association of the Korean Oriental Medicine. A stratified random sample of Korean medical doctors is drawn for the telephone interviews. We choose a bound on the error of estimation equal to 3.2 percentage, and the sample size is 321 for the national sample. We develop a questionnaire for telephone interviews. We carefully design the questionnaire to minimize non-sampling errors by using the focus group activities and the pretest. We give the details of the results based on the sample design. Also, we present some socialdemograhpic characteristics for the samples. Telephone interviews with them were conducted by the well-trained interviewers of College of Korean Medicine student from 11th May 2006 to 17th May 2006. Results : 1. Two hundred eighty eight(89.4%) out of 322 Korean oriental medical doctors used bloodletting therapeutics. 2. The most common main bloodletting treatment is reported by patients was musculo-skeletal disorder(60.2%). 3. Two hundred ninety one(90.3%) out of 322 Korean oriental medical doctors opposed that commercial using bloodletting without medical diagnosis. Conclusion : Bloodletting therapeutics is one of the most popular oriental treatments in Korea. The majority(89.4%) of Korean medical doctors used bloodletting therapeutics in this survey.

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Systematic Forecasting Bias of Exit Poll: Analysis of Exit Poll for 2010 Local Elections (출구조사의 체계적인 예측 편향에 대한 분석: 2010년 지방선거 출구조사를 중심으로)

  • Kim, Young-Won;Choi, Yun-Jung
    • Survey Research
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    • v.12 no.3
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    • pp.25-48
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    • 2011
  • In this paper, we overview the sample design, sampling error, non-response rate and prediction errors of the exit poll conducted for 2010 local elections and discusses how to detect a prediction bias in exit poll. To investigate the bias problem in exit poll in regional(Si-Do) level, we analyze exit poll data for 2007 presidential election and 2006 local elections as well as 2010 local elections in Korea. The measure of predictive accuracy A proposed by Martin et al.(2005) is used to assess the exit poll bias. The empirical studies based on three exit polls clearly show that there exits systematic bias in exit poll and the predictive bias of candidates affiliated to conservative party (such as Hannara-Dang) is serious in the specific regions. The result of this study on systematic bias will be very useful to improving the exit poll methodology in Korea.

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Clean techniques for trace metal analysis in natural waters (자연수 중의 미량금속 분석을 위한 청결기술)

  • Kim, Kyung-Tae;Kim, Eun-Soo;Cho, Sung-Rok;Park, Jun-Kun;Moon, Deok-Soo;Kim, Hyeon-Ju
    • Proceedings of KOSOMES biannual meeting
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    • 2007.11a
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    • pp.43-49
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    • 2007
  • The metals we are familiar with(Al, Ag, Au, Cu, Cd, Co, Fe, Ni, Pb, Zn, etc) are common elements and conservative pollutants. Although metals are often vital constituents of the metabolism of living organisms(trace elements}, a number of them are toxic if their concentration exceeds a certain threshold. It has long been recognized that measurements of trace metals in natural waters are often subject to large errors in terms of precision and accuracy. Since 1975 in US and European countries, seawater concentration of many trace metals have been shown to be factors of 10-1,000 lower than those previously accepted. Vertical profiles have been found to be consistent with known biological, physical and/or geochemical processes. These are resulted from major advances in analytical instrumentation and methodology for trace elements, and greater attention has been given to assuring the elimination of contamination during sampling, storage, and analysis.

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3D Face Alignment and Normalization Based on Feature Detection Using Active Shape Models : Quantitative Analysis on Aligning Process (ASMs을 이용한 특징점 추출에 기반한 3D 얼굴데이터의 정렬 및 정규화 : 정렬 과정에 대한 정량적 분석)

  • Shin, Dong-Won;Park, Sang-Jun;Ko, Jae-Pil
    • Korean Journal of Computational Design and Engineering
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    • v.13 no.6
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    • pp.403-411
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    • 2008
  • The alignment of facial images is crucial for 2D face recognition. This is the same to facial meshes for 3D face recognition. Most of the 3D face recognition methods refer to 3D alignment but do not describe their approaches in details. In this paper, we focus on describing an automatic 3D alignment in viewpoint of quantitative analysis. This paper presents a framework of 3D face alignment and normalization based on feature points obtained by Active Shape Models (ASMs). The positions of eyes and mouth can give possibility of aligning the 3D face exactly in three-dimension space. The rotational transform on each axis is defined with respect to the reference position. In aligning process, the rotational transform converts an input 3D faces with large pose variations to the reference frontal view. The part of face is flopped from the aligned face using the sphere region centered at the nose tip of 3D face. The cropped face is shifted and brought into the frame with specified size for normalizing. Subsequently, the interpolation is carried to the face for sampling at equal interval and filling holes. The color interpolation is also carried at the same interval. The outputs are normalized 2D and 3D face which can be used for face recognition. Finally, we carry two sets of experiments to measure aligning errors and evaluate the performance of suggested process.

Nonignorable Nonresponse Imputation and Rotation Group Bias Estimation on the Rotation Sample Survey (무시할 수 없는 무응답을 가지고 있는 교체표본조사에서의 무응답 대체와 교체그룹 편향 추정)

  • Choi, Bo-Seung;Kim, Dae-Young;Kim, Kee-Whan;Park, You-Sung
    • The Korean Journal of Applied Statistics
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    • v.21 no.3
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    • pp.361-375
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    • 2008
  • We propose proper methods to impute the item nonresponse in 4-8-4 rotation sample survey. We consider nonignorable nonresponse mechanism that can happen when survey deals with sensitive question (e.g. income, labor force). We utilize modeling imputation method based on Bayesian approach to avoid a boundary solution problem. We also estimate a interview time bias using imputed data and calculate cell expectation and marginal probability on fixed time after removing estimated bias. We compare the mean squared errors and bias between maximum likelihood method and Bayesian methods using simulation studies.

Estimation of the Forest Stand Volumes from Forest Inventory Data Based on Synthetic Estimation Method: A Case of the Economic Forest in Gangwon-do, Republic of Korea

  • Seo, Hwan seok;Park, Jeong mook;Lee, Jung soo
    • Journal of Forest and Environmental Science
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    • v.32 no.2
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    • pp.140-148
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    • 2016
  • This study aims to estimate the forest volumes of the economic forest in Gangwon Province of Republic of Korea (hereinafter referred to as Gangwon) through the synthetic estimation. To estimate the forest volume, Stratified systematic sampling method was used along with the forest type maps and the $5^{th}$ National Forest Inventory data. The synthetic estimation includes sample plots of the expanded areas as well as those of the target area, and the forest volume of economic forest in every city and county throughout Gangwon. Results show that the average forest volume calculated by synthetic estimation was $159.6m^3/ha$ in national economic forest and $129.6m^3/ha$ in private economic forest. The total forest volume of the national economic forest was approximately $59.45million\;m^3$, which was $20.18million\;m^3$ higher than that of the private economic forest. On the other hands, the standard error of the national economic forest was approximately ${\pm}2.21m^3/ha$, which was ${\pm}0.30m^3/ha$ lower than that of the private economic forest. The lowest standard errors was about ${\pm}3.12 m^3/ha$ in broad-leaved forest, followed by ${\pm}4.33m^3/ha$ of mixed forest, and ${\pm}5.78m^3/ha$ of coniferous forest.

Evaluation of Ground Characteristic Using the New Developed Screw Plate Load Test Device (새롭게 개발된 스크류재하시험장치를 이용한 지반특성 파악)

  • Lee, Nam-Woo;Hwang, Woong-Ki;Choi, Yong-Kyu;Kim, Tae-Hyung
    • Journal of the Korean Geotechnical Society
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    • v.27 no.3
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    • pp.5-17
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    • 2011
  • Sampling disturbance can often introduce considerable errors in the laboratory estimation of geotechnical properties of soils. Accordingly, it causes inappropriative results in analysing field behavior. Therefore, a screw plate load test, one of in-situ test technique, is developed in this study, because in-situ testing techniques have advantages for the estimation of reliable geotechnical parameters. The screw plate load test, which was modified from the plate load test, conducts an experiment underneath ground by inserting a spiral type of auger screw. In this study, the structure and characteristics of the screw plate load test device are introduced in detail and the reliability of the device is examined through the analysis of the laboratory test results.

Surveying and Optimizing the Predictors for Ependymoma Specific Survival using SEER Data

  • Cheung, Min Rex
    • Asian Pacific Journal of Cancer Prevention
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    • v.15 no.2
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    • pp.867-870
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    • 2014
  • Purpose: This study used receiver operating characteristic curve to analyze Surveillance, Epidemiology and End Results (SEER) ependymoma data to identify predictive models and potential disparity in outcome. Materials and Methods: This study analyzed socio-economic, staging and treatment factors available in the SEER database for ependymoma. For the risk modeling, each factor was fitted by a Generalized Linear Model to predict the outcome ('brain and other nervous systems' specific death in yes/no). The area under the receiver operating characteristic curve (ROC) was computed. Similar strata were combined to construct the most parsimonious models. A random sampling algorithm was used to estimate the modeling errors. Risk of ependymoma death was computed for the predictors for comparison. Results: A total of 3,500 patients diagnosed from 1973 to 2009 were included in this study. The mean follow up time (S.D.) was 79.8 (82.3) months. Some 46% of the patients were female. The mean (S.D.) age was 34.4 (22.8) years. Age was the most predictive factor of outcome. Unknown grade demonstrated a 15% risk of cause specific death compared to 9% for grades I and II, and 36% for grades III and IV. A 5-tiered grade model (with a ROC area 0.48) was optimized to a 3-tiered model (with ROC area of 0.53). This ROC area tied for the second with that for surgery. African-American patients had 21.5% risk of death compared with 16.6% for the others. Some 72.7% of patient who did not get RT had cerebellar or spinal ependymoma. Patients undergoing surgery had 16.3% risk of death, as compared to 23.7% among those who did not have surgery. Conclusion: Grading ependymoma may dramatically improve modeling of data. RT is under used for cerebellum and spinal cord ependymoma and it may be a potential way to improve outcome.

Study on Factors Affecting Nurses' Experience of Non-Reporting Incidents (병원 간호사의 사건보고 불이행 경험여부에 영향을 미치는 요인)

  • Kim, Ki-Kyong;Song, Mal-Soon;Rhee, Kae-Sook;Hur, Hea-Kung
    • Journal of Korean Academy of Nursing Administration
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    • v.12 no.3
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    • pp.454-463
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    • 2006
  • Purpose: This study was designed to identify the factors affecting the nurses' experience of non-reporting adverse incidents in hospital. Methods: This study is a cross-sectional, descriptive survey design and nonrandom, convenience sampling. Study subjects were 392 clinical nurses, who have agreed to be the subject of this research. The measuring instrument of attitudes toward incident reporting was developed by the authors. The questionnaire which consisted of 17 items about worry about appraisal, the belief in improvement, the intention of reporting, and knowledge was measured by 5-point Likert-type scale. The estimate of internal consistency was alpha =.84. Analysis of data was done with use of mean, t-test, ANOVA, logistic regression with SPSS program. Results: Clinical nurses had experience of reporting incident (51.3%), non-reporting incident (76.5%). Statistically, significant differences were found between experiences group and non experience group in intention on reporting, belief on improvement, and worry about appraisal. Logistic regression analysis showed that the significant predictors were caused by report no-fault cases, belief on improvement, worry about appraisal. Conclusion: The result also indicated that, to improve the incident reporting and risk management, it might be necessary to give a belief that it results on improvement and remove concern about punishment through construction of no-blame system.

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Application of In-direct Estimation for Small Area Statistics (소지역 통계분석기법의 활용-도소매업 및 서비스업 통계조사 사례연구-)

  • 김영원;성나영
    • Proceedings of the Korean Association for Survey Research Conference
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    • 2000.06a
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    • pp.57-73
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    • 2000
  • Small area estimation is becoming important in survey sampling due to a growing demand for reliable small area statistics. In estimating means, totals, and other parameters for small areas of a finite population, samplie sizes for small areas are typically small because the overall sample size is usually determined to provide specific accuracy at a much higher level of aggregation than that of small area. The usual direct estimators that use the only information which is gotten from the sample in a given small area provide unreliable estimates. However, indirect estimators utilize the information from the areas related with a given small area, that is borrow strength from other related areas, and so give more accurate estimates than direct estimators. In this paper we investigate small area estimation methods such as synthetic, composite and empirical best linear unbiased prediction estimator, and apply them to real domestic data which is from the Survey of Hotels and Restaurants in In-Chon as of 1996 and then evaluate the performance of these methods by measuring average squared errors. This evaluation shows that indirect estimators, which are small area estimation methods, are more efficient direct estimator.

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