• Title/Summary/Keyword: 일단계

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Design-based Variance Estimation under stratified Multi-stage Sampling (층화 다단계 샘플링에서 설계 기반 분산추정)

  • 김규성
    • Proceedings of the Korean Association for Survey Research Conference
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    • 2001.04a
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    • pp.59-71
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    • 2001
  • We investigate design-based variance estimation methods of homogeneous linear estimator for population total under stratified multi-stage sampling. One method is unbiasedly estimating the first stage variance and the second stage variance separately in each stratum. And another is sub-sampling method that estimating the first stage variance only by using sub-sample selected from the second stage sample so that resulting estimator is unbiased for the total variance. The first is useful when the second stage unbiased estimator is available and the second is when the second stage variance is not estimable. For each case, we proposed a form of non-negative unbiased variance estimator. We expect the proposed variance estimation methods can be effectively used for many practical surveys.

Design-based Variance Estimation under Stratified Multi-stage Sampling (층화 다단계 샘플링에서 설계 기반 분산추정)

  • 김규성
    • Survey Research
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    • v.2 no.1
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    • pp.59-71
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    • 2001
  • We investigate design-based variance estimation methods of homogeneous linear estimator for population total under stratified multi-stage sampling. One method is unbiasedly estimating the first stage variance and the second stage variance separately in each stratum. And another is sub-sampling method that estimating the first stage variance only by using sub-sample selected from the second stage sample so that resulting estimator is unbiased for the total variance. The first is useful when the second stage unbiased estimator is available and the second is when the second stage variance is not estimable. For each case, we proposed a form of non-negative unbiased variance estimator. We expect the proposed variance estimation methods can be effectively used for many practical surveys.

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Surgical Results and Risk Facor Analysis of the Patients with Single Ventricle Associated with Total Anomalous Pulmonary Venous Connection (총폐정맥연결이상증을 동반한 단심증 환아의 수술결과 및 위험인자 분석)

  • 이정렬;김창영;김홍관;이정상;김용진;노준량
    • Journal of Chest Surgery
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    • v.35 no.12
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    • pp.862-870
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    • 2002
  • The surgical results of the patients with single ventricle(SV) associated with total anomalous pulmonary venous connection(TAPVC) has been reported with high mortality and morbidity due to their morphologic and hemodynamic complexity. A retrospective review was undertaken to report the outcome of the first-stage palliative surgery in our institution and to determine the factors influencing early death. Material and Method: Between January 1987 and June 2002, 39 patients with SV and TAPVC underwent surgical intervention with or without TAPVC repair. Age at operation ranged from 1day to 10.7months (median age, 2.4month), and 29 patients were male. Preoperative diagnosis included 20 right-dominant SV, 15 SV with endocardial cushion defect, 3 left-dominant SV, and 1 tricuspid atresia. The pulmonary venous connection was supracardiac in 22, cardiac in 5, infracardiac in 11, and mixed in 1, Obstructed TAPVC was present in 11. First-stage palliative surgery was performed in 37. Repair of TAPVC, either alone or in association with other procedures, was performed during the initial operation in 31. Univariate and multivariate analyses were performed to analyze the risk factors influencing the operative death. Result: A mean follow-up period of survivors was 34.3 $\pm$ 43.0(0.53 ~ 146.2)months. Overall early operative mortality was 43.6%(17/39). The causes were low cardiac output in 8, failure of weaning from cardiopulmonary bypass in 3, sepsis in 2, pulmonary hypertensive crisis in 1, pulmonary edema in 1, pneumonia in 1, and postoperative arrhythmia in 1. Risk factors influencing early death in univariate analysis were body weight, surgical intervention in neonate, obstructive TAPVC, preoperative conditions including metabolic acidosis, and need for inotropic support, TAPVC repair in initial operation, operative time, and cardiopulmonary bypass(CPB) time. In multivariable analysis, body weight, age at initial operation, surgical intervention in neonate, preoperative conditions including metabolic acidosis, need for inotropic support and CPB time were the risk factors. Conclusion: In this study, we demonstrated that the patients with SV and TAPVC had high perioperative mortality. Preoperative poor condition, young age, the length of operative and CPB time, the presence of obstructive TAPVC had been proven to be the risk factors. This fact suggests that the avoidance of unnecessarily additional procedures may improve the surgical outcomes of the first-stage palliative surgery. However further observation and collection of the data is mandatory to determine the ideal surgical strategy.

Effects of Parameter Estimation in Phase I on Phase II Control Limits for Monitoring Autocorrelated Data (자기상관 데이터 모니터링에서 일단계 모수 추정이 이단계 관리한계선에 미치는 영향 연구)

  • Lee, Sungim
    • The Korean Journal of Applied Statistics
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    • v.28 no.5
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    • pp.1025-1034
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    • 2015
  • Traditional Shewhart control charts assume that the observations are independent over time. Current progress in measurement and data collection technology lead to the presence of autocorrelated process data that may affect poor performance in statistical process control. One of the most popular charts for autocorrelated data is to model a correlative structure with an appropriate time series model and apply control chart to the sequence of residuals. Model parameters are estimated by an in-control Phase I reference sample since they are usually unknown in practice. This paper deals with the effects of parameter estimation on Phase II control limits to monitor autocorrelated data.

Robust One-step Receding Horizon Control for Constrained Systems (제한적 시스템을 위한 강인한 일단계 이동구간 제어)

  • Park, Byung-Gun;Kwon, Wook-Hyun;Lee, Jae-Won
    • Proceedings of the KIEE Conference
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    • 1998.11b
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    • pp.469-471
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    • 1998
  • 이논문은 입력과 상태변수에 제한조건이 있는 이산형 불확실 선형 시스템을 위한 강인한 이동구간 제어기를 제시한다. 모델 변수는 콘벡스 집합에 속하는 불확실성 성질을 갖는다. 제안된 이동구간 제어기는 터미널 가중치 행렬들과 입력과 상태변수의 제한조건을 가지는 최악의 일단계 목적함수의 최소화에 기초한다. 제안된 이동구간 제어기는 위의 불확실한 시스템을 일정한 터미널 가중치 행렬에 대한 행렬 부등식 조건하에서 안정화 시킬수 있다는 것을 보인다. 이 강인 이동구간 제어기는 기존의 무한 구간 강인 이동구간 제어기보다 같은 설계 조건하에서 보다 더 일반적인 구조와 더 큰 간으한 초기 상태 영역을 갖는다. 이 제시된 이동구간 제어기는 반한정 프로그래밍을 이용하여 얻어진다.

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One Stage Revision Anterior Cruciate Ligament Reconstruction (일단계 전방 십자 인대 재 재건술)

  • Ra, Ho-Jong;Ha, Jeong-Ku;Kim, Sang-Bum;Sung, Jung-Hwan;Seo, Jeong-Gook;Kim, Jin-Goo
    • Journal of the Korean Arthroscopy Society
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    • v.13 no.2
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    • pp.143-148
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    • 2009
  • Purpose: To investigate the causes of failure on ACL reconstructions and evaluate the effectiveness of one stage revision ACL reconstructions. Materials and Methods: From November 2004 to July 2008, thirty three patients who had got revision ACL recontstructions after reruptures of ACL were evaluated. The causes of failure of ACL reruptures were 22 vertical femoral tunnels, 7 neglected PLRI, 3 severe traumas and 1 deep infection after ACL reconstruction. The femoral tunnels were aimed at the 10 or 2 o'clock position and the tibial tunnels were used with previous tunnels. Previous femoral screws from the improper femoral tunnels were removed and filled with the new allograft bones. Results: The average periods of follow up were 22.2 months (12~52 months). There was improvement on an average Lysholm knee score from $61.5{\pm}16.8$ to $86.3{\pm}11.5$, IKDC score from $63.9{\pm}15.1$ to $81.3{\pm}14.3$. Mean side to side difference was decreased from $6.0{\pm}2.2\;mm$ to $1.6{\pm}1.4\;mm$ using KT-2000 arthrometer. Conclusion: One stage revision ACL reconstruction can be a useful method with good clinical results.

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공간영상정보의 구축에 따른 항공사진의 활용 방안

  • 김계현;이경숙;민숙주;유승근
    • Proceedings of the KSRS Conference
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    • 2000.04a
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    • pp.177-177
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    • 2000
  • 정부에서는 NGIS 이단계 사업의 추진에 앞서 위성자료를 활용한 공간영상정보를 구축하여 기존에 NGIS 일단계에서 구축된 기본도와 NGIS 이단계에서 구축예정인 다양한 주제도와 공통주제도, 나아가 주요 분야별 프레임워크데이터의 효율적 갱신에 활용할 예정이다. 이러한 공간영상정보는 동시성과 주기성, 광역성을 가지고 1-2m의 고해상도까지 정보의 제공이 가능하므로 향후 주제도의 구축과 갱신에 기여도가 매우 높으리라 예상된다. 아울러 기존에 오랜 기간 제작된 항공사진을 적정 해상력으로 스캐닝하여 공간DB화 함으로서 위성자료와 연계된 과거와 현재의 시계열 자료를 확보함으로써 보다 다양한 대국민 정보서비스가 가능하리라 판단된다. 이와 함께 지방자치단체에서도 그동안 축척된 항공사진을 공간DB화하여 도시계획과 녹지관리, 하천 및 환경관리 등을 위하여 활용이 크리라 예상된다. 본 연구에서는 이를 위한 공간영상정보화된 항공사진의 관리와 제공을 위한 관리시스템의 개발과 정확도 관리 방안, 검수 방안, 사용자를 위한 메타데이터 제공방안 등을 제시하고자 한다.

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Generalized Predictor-Corrector Method

  • 함남우
    • Proceedings of the Korean Society of Computational and Applied Mathematics Conference
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    • 2003.09a
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    • pp.16.2-16
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    • 2003
  • 미분 방정식의 수치적 해를 나타내는 방법 중 예측자-수정자 방법(predictor-corrector method)으로 알려진 Adams-Bashford-Moulton 방법은 다단계 방법을 이용하기 때문에 일단계 방법에 비하여 훨씬 좋은 수치적인 결과를 보여주고 있다. 이제, 이 다단계 방법에 오차제어 변수를 첨가한 새로운 형태의 예측자-수정자 방법을 제시하고 안정적인 해를 구할 수 있는 오차 제어 변수의 범위를 확인한다. 또한, 새로운 형태의 예측자-수정자 방법이 기존의 방법에 비하여 미분 방정식의 해에 대한 오차를 줄일 수 있는 방법임을 수치적인 결과를 통하여 검증한다.

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중소기업의 생산관리에 활용되는 컴퓨터

  • 대한전기협회
    • JOURNAL OF ELECTRICAL WORLD
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    • no.6 s.90
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    • pp.93-99
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    • 1984
  • 제조업의 중소기업에서 컴퓨터의 활용은 수발주 관리로부터 생산관리에 이르기까지 이를 활용해야 할 때가 왔다. 생산관리는 시스템이 복잡하기 때문에 수발주관리처럼 간단하지 않다. 생산관리의 컴퓨터화에는 먼저 재고관리를 도입하여 충분히 활용해야할 것이며 그로부터 종합적관리로 진행하는 2단계가 있다. 종합적관리로 진행하는데 있어서는 컴퓨터 활용 레벨을 일단계 높이고 각각의 개별관리를 상호 유기적으로 결부시킬 필요가 있다. 여기서는 중소기업의 생산관리에 컴퓨터를 도입할 경우 개별관리에서 종합적관리로 진행하는 2단계에 대해서 실례를 들어 기술하겠다.

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