• 응용통계연구
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• 제18권1호
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• pp.129-135
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• 2005

일변량 자료의 경우 대표관찰치는 사분위수 등에 기초하여 자료의 분포와 변이를 함축적으로 표현하기 위한 목적으로 사용되는 소수 개의 관찰치이다. Jones와 Rice(1992)는 다변량 자료에 대한 대표관찰치를 선택하기 위해 주성분분석에 근거한 방법을 제시한 바 있다. 이 연구에서는 주성분의 자기일치성을 이용하여 대표관찰치를 선택하고, 이를 표현하는 방안을 고찰한다. 기존의 방법에 의한 대표관찰치가 자료의 표본변이에 민감한 한편, 여기에서 제안되는 방법의 결과는 자기일치성을 가진다.

• 대한기계학회논문집A
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• 제25권9호
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• pp.1384-1390
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• 2001

This paper deals with the forward kinematics of the 6-6 Stewart platform of planar base and moving platform using one extra linear sensor. Based on algebraic elimination method, it first derives an 8th-degree univariate equation and then finds tentative solution sets out of which the actual solution is to be selected. In order to provide more exact solution despite the error between measured sensor value and the theoretic alone, a correction method is also used in this paper. The overall procedure requires so little computation time that it can be efficiently used for real-time applications. In addition, unlike the iterative scheme e.g. Newton-Raphson, the algorithm does not require initial estimates of solution and is free of the problems that it does not converge to actual solution within limited time. The presented method has been implemented in C language and a numerical example is given to confirm the effectiveness and accuracy of the developed algorithm.

• 산업경영시스템학회지
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• 제41권2호
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• pp.174-183
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• 2018

In the industrial fields, the process capability index has been using to evaluate the variation of quality in the process. The traditional process capability indices such as $C_p$, $C_{pk}$, $C_{pm}$ and $C^+_{pm}$ have been applied in the industrial fields. These traditional process capability indices are mainly applied in the univariate analysis. However, the main streams in the recent industry are the multivariate manufacturing process and the multiple quality characteristics are corrected each other. Therefore, the multivariate statistical method should be used in the process capability analysis. The multivariate process indices need to be enhanced with more useful information and extensive application in the recent industrial fields. Hence, the purpose of the study is to develop a more effective multivariate process index ($MC_{pI}$) using the multivariate inverted normal loss function. The multivariate inverted normal loss function has the flexibility for the any type of the symmetrical and asymmetrical loss functions as well as the economic information. Especially, the proposed modeling method for the multivariate inverted normal loss function (MINLF) and the expected loss from MINLF in this paper can be applied to the any type of the symmetrical and asymmetrical loss functions. And this modeling method can be easily expanded from a bivariate case to a multivariate case.

• Journal of Chest Surgery
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• 제42권5호
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• pp.610-614
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• 2009

배경: 완전 절제된 IB 비소세포암에서 항암요법의 반드시 필요한가에 대한 여러 보고가 있다. 그래서 본 연구는 완전 절제된 IB 비소세포암 환자에서 재발에 관여하는 예후인자를 찾고 항암요법의 필요성을 알아보았다. 대상 및 방법: 1997년부터 2006년까지 모두 48명의 환자를 후향적으로 조사하였다. 전체생존율과 무병생존율을 위해 Kaplan-Meier method를 사용하였고 단변량 분석은 log rank, 다변량 분석은 Cox 회귀모형을 사용하였다. 결과: 추적중앙값은 48개월, 5년 전체생존율은 55.9%, 5년 무병생존율은 48.6%였다. 단변량 분석에서 장측늑막과 임파혈관 침범이 재발에 유의한 인자였고, 다변량분석에서는 장측늑막침범이 예후인자였다. 또한 장측늑막, 임파혈관 침범 중 한 개 이상의 경우, 없는 경우와 비교하여 전체 생존율에서 의미 있는 차이가 있었다. 결론: 장측늑막침범은 재발 및 생존에 관여하는 불량한 예후인자이며, 항암요법이 필요한 환자를 선택할 때 도움 되는 인자로 생각된다.

• 기술경영경제학회:학술대회논문집
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• 기술경영경제학회 1996년도 제10회 동계학술발표회 논문집
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• pp.63-76
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• 1996

This study investigates the factors determining accounting method for R & D costs (capitalize vs. expense) in Korea. Using agency theory and other economic factors, probit and regression models have been developed to distinguish between firms choosing different accounting alternatives for R&D costs. The results are consistent to debt contract, R&D burden and regulation hypotheses both in probit and regression analysis. The size variable has opposite sign in univariate t-test and probit analysis but the signs are mixed and insignificant in regression which may be due to the differences of political environment between Korea and the US. Generally, the results are consistent to those of previous research. The results support the hypothesis that firms with higher leverage and larger burden of R&D costs are more likely to capitalize R&D costs. Partially, larger and regulated firms are more likely to expense R & D costs.

• Asian Pacific Journal of Cancer Prevention
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• 제14권4호
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• pp.2567-2570
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• 2013

Background: This study analyzed Surveillance, Epidemiology and End Results (SEER) data to assess if socio-economic factors (SEFs) impact on endometrial cancer survival. Materials and Methods: Endometrial cancer patients treated from 2004-2007 were included in this study. SEER cause specific survival (CSS) data were used as end points. The areas under the receiver operating characteristic (ROC) curve were computed for predictors. Time to event data were analyzed with Kaplan-Meier method. Univariate and multivariate analyses were used to identify independent risk factors. Results: This study included 64,710 patients. The mean follow up time (S.D.) was 28.2 (20.8) months. SEER staging (ROC area of 0.81) was the best pretreatment predictor of CSS. Histology, grade, race/ethnicity and county level family income were also significant pretreatment predictors. African American race and low income neighborhoods decreased the CSS by 20% and 3% respectively at 5 years. Conclusions: This study has found significant endometrial survival disparities due to SEFs. Future studies should focus on eliminating socio-economic barriers to good outcomes.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2004년도 ICCAS
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• pp.863-868
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• 2004

Reheating furnace is an essential facility of a rod mill plant where a billet is heated to the required rolling temperature so that it can be milled to produce wire. Sometimes, it is also necessary to control a transient billet temperature pattern according to the material characteristics to prevent a wire from breaking. Though it is very important objective to obtain a correct information of a billet temperature during furnace operation. Consequently, a billet temperature profile must be estimated. In this paper, a billet heat transfer model based on FEM (Finite Element Method) with spatially distributed emission factors is proposed and a measurement is also carried out for two different furnace operation conditions. Finally, the difference between the model outputs and the measurements is minimized by using the new optimization algorithm named uDEAS(Univariate Dynamic Encoding Algorithm for Searches) with multi-step tuning strategy. Hence, the information of billet temperatures can be obtained by using proposed model on various furnace operation conditions.

• Asian Pacific Journal of Cancer Prevention
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• 제17권10호
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• pp.4693-4697
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• 2016

Aim: The objective of this study is to investigate prognostic factors affecting survival of patients undergoing concurrent or sequential chemoradiotherapy (CRT) for stage III non-small-cell lung cancer (NSCL). Methods and materials: We retrospectively reviewed the clinical records of 148 patients with advanced, inoperable stage III NSCLC, who were treated between 2007 and 2015. Results: The median survival was found to be 19 months and 3-year overall survival was 27%. Age (<65 vs ${\geq}65years$, p=0.026), stage (IIIA vs IIIB, p=0.033), dose of radiotherapy (RT) (<60 vs ${\geq}60Gy$, p=0.024) and treatment method (sequential chemotherapy+RT vs concurrent CRT, p=0.023) were found to be factors affecting survival in univariate analyses. Gender, histological subtype, weight loss during CRT, performance status, induction/consolidation chemotherapy and presence of comorbidities did not affect survival (p>0.050). Conclusion: Young age, stage IIIA, radiotherapy dose and concurrent chemoradiotherapy may positively affect survival in stage III NSCL cases.

• 한국작물학회지
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• 제43권2호
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• pp.128-133
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• 1998

Analyses of now karyotypes using different maize (Zea mays L.) inbred lines have been performed. The accumulation and isolation of high quality and quantity metaphase chromosomes from root tips can be achieved from many kinds of maize lines. The chromosome suspensions were prepared by a simple slicing method from synchronized maize root tips and analyzed with a now cytometry. The variations of experimental now karyotypes were detected among inbred lines in terms of the positions and/or the numbers of chromosome peaks. The 2C DNA amount among 8 inbred lines ranged from 5.09 to 5.52 pg. The variability of DNA content in maize chromosome 1 was 9.1 % ranging from 0.685 to 0.747 pg. The selection of appropriate maize lines is critical for sorting specific single chromosome types. At least five different chromosome types can be discriminated and sorted from five maize lines.

• 한국환경과학회지
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• 제8권3호
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• pp.349-354
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• 1999

The transfer function was introduced to establish the prediction method for the DO concentration at the intaking point of Kongju Water Works System. In the mose cases we analyze a single time series without explicitly using information contained in the related time series. In many forecasting situations, other events will systematically influence the series to be forecasted(the dependent variables), and therefore, there is need to go beyond a univariate forecasting model. Thus, we must bulid a forecasting model that incorporates more than one time series and introduces explicitly the dynamic characteristics of the system. Such a model is called a multiple time series model or transfer function model. The purpose of this study is to develop the stochastic stream water quality model for the intaking station of Kongju city waterworks in Keum river system. The performance of the multiplicative ARIMA model and the transfer function noise model were examined through comparisons between the historical and generated monthly dissolved oxygen series. The result reveal that the transfer function noise model lead to the improved accuracy.