• Journal of Korean Neurosurgical Society
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• 제56권4호
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• pp.303-309
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• 2014

Objective : The purpose of this study was to retrospectively review cases of intracerebral hemorrhage (ICH) medically treated at our institution to determine if the CT angiography (CTA) 'spot sign' predicts in-hospital mortality and clinical outcome at 3 months in patients with spontaneous ICH. Methods : We conducted a retrospective review of all consecutive patients who were admitted to the department of neurosurgery. Clinical data of patients with ICH were collected by 2 neurosurgeons blinded to the radiological data and at the 90-day follow-up. Results : Multivariate logistic regression analysis identified predictors of poor outcome; we found that hematoma location, spot sign, and intraventricular hemorrhage were independent predictors of poor outcome. In-hospital mortality was 57.4% (35 of 61) in the CTA spot-sign positive group versus 7.9% (10 of 126) in the CTA spot-sign negative group. In multivariate logistic analysis, we found that presence of spot sign and presence of volume expansion were independent predictors for the in-hospital mortality of ICH. Conclusion : The spot sign is a strong independent predictor of hematoma expansion, mortality, and poor clinical outcome in primary ICH. In this study, we emphasized the importance of hematoma expansion as a therapeutic target in both clinical practice and research.

• Asian Journal of Business Environment
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• 제11권4호
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• pp.17-29
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• 2021

Purpose: The aim of this study is to explore the dynamic linkage between conditional stock market volatility and macroeconomic uncertainty of Bangladesh. Research design, data, and methodology: This study uses monthly data covering the time period from January 2005 to December 2018. A comprehensive set of macroeconomic variables, namely industrial production index (IP), consumer price index (CPI), broad money supply (M2), 91-day treasury bill rate (TB), treasury bond yield (GB), exchange rate (EX), inflow of foreign remittance (RT) and stock market index of DSEX are used for analysis. Symmetric and asymmetric univariate GARCH family of models and multivariate VAR model, along with block exogeneity and impulse response functions, are implemented on conditional volatility series to discover the possible interactions and causal relations between macroeconomic forces and stock return. Results: The analysis of the study exhibits time-varying volatility and volatility persistence in all the variables of interest. Moreover, the asymmetric effect is found significant in the stock return and most of the growth series of macroeconomic fundamentals. Results from the multivariate VAR model indicate that only short-term interest rate significantly influence the stock market volatility, while conditional stock return volatility is significant in explaining the volatility of industrial production, inflation, and treasury bill rate. Conclusion: The findings suggest an increasing interdependence between the money market and equity market as well as the macroeconomic fundamentals of Bangladesh.

• 한국지형학회지
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• 제19권3호
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• pp.37-49
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• 2012

이 논문의 목적은 간석지 표층 퇴적상 분류를 목적으로 다변량 크리깅을 기반으로 고해상도 원격탐사 자료와 현장 조사 자료를 결합하는 방법론을 제안하는데 있다. 퇴적물 성분에 따라 미리 범주화시킨 퇴적물 자료를 사용하여 원격탐사 자료를 분류하는 기존 방법론과 달리 현장 조사 자료와 원격탐사 자료를 이용하여 퇴적물 성분별 분포도를 제작한 후에 최종 단계에서 범주화 시키는 분류 방법론을 제안하였다. 퇴적물 성분별 분포도 제작 과정에서 현장 조사 자료와 원격탐사 자료의 결합을 위해 다변량 크리깅 기법인 회귀 크리깅 기법을 이용하였다. 우선 현장조사 자료의 모래, 실트, 점토 성분별로 고해상도 원격탐사 자료의 분광 정보와 회귀 분석을 수행하여, 각 성분별 경향 성분을 추출하였다. 그리고 현장 조사 자료 위치에서 잔차를 계산한 후에, 잔차에 대해 크리깅을 적용하여 잔차분포도를 얻게 된다. 이후 성분별 경향 성분과 잔차 성분을 합하여 성분별 비율 분포도를 작성한 후에 최종 단계에서 퇴적상 분류를 수행하게 된다. 제안 기법의 적용성 평가를 위해 바람아래 간석지를 대상으로 고해상도 KOMPSAT-2 자료를 이용한 사례 연구를 수행하였다. 사례 연구를 통해 제안 기법이 기존 분류 방법에 비해 상대적으로 높은 분류 정확도를 나타내었으며, 특히 세립질 퇴적물 분류에 더 우수한 것으로 나타났다. 따라서 제안 기법은 원격탐사 자료를 이용한 간석지 표층 퇴적상 분류에 유용하게 사용될 수 있을 것으로 기대된다.

• Asian Pacific Journal of Cancer Prevention
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• 제15권19호
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• pp.8101-8105
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• 2014

Background: Although mucinous adenocarcinoma has been recognized for a long time, whether it is associated with a poorer prognosis in colorectal cancer patients is still controversial. Many studies put emphasis on mucinous adenocarcinoma containing mucin component ${\geq}50%$. Only a few studies have analyzed cases with a mucin component <50%. Objectives: This study aimed to analyze the prognostic value of different mucin component proportions in patients with stage III rectal cancer. Materials and Methods: Clinical, pathological and follow-up data of 136 patients with the stage III rectal cancer were collected. Every variable was analyzed by univariate analysis, then multivariate analysis and survival analysis were further performed. Results: Univariate analysis showed pathologic T stage, lymphovascular invasion, and histological subtype were statistically significant for DFS. Pathologic T stage was significant for OS. Histological subtype and lymphovascular invasion were independent prognostic factors in multivariate analysis for DFS, and histological subtype was the only independent prognostic factor for OS. Survival curves showed the survival time of mucinous adenocarcinoma (MUC) was shorter than non-MUC (adenocarcinomas with a mucin component <50% and without mucin component). Conclusions: Histological subtype (tumor with different mucin component) was an independent prognostic factor for both DFS and OS. Patients with MUC had a worse prognosis than their non-MUC counterparts with stage III rectal carcinoma.

• Journal of Forest and Environmental Science
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• 제37권4호
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• pp.269-279
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• 2021

This study was carried out to introduce the forest cover types of the Baekdudaegan inhabiting the number of native tree species. In order to understand the vegetation distribution characteristics of the Baekdudaegan, a vegetation survey was conducted on the major 20 mountains of the Baekdudaegan. The vegetation data were collected from 3,959 sample points by the point-centered quarter method. Each mountain was classified into 4-7 forests by using various multivariate statistical methods such as cluster analysis, indicator species analysis, multiple discriminant analysis, and species composition analysis. The forests were classified mainly according to the relative abundance of Quercus mongolica. There was a total of 111 classified forests and these forests were integrated into the following nine forest cover types using the percentage similarity index and by clustering according to vegetation type: 1) Mongolian oak, 2) Mongolian oak and other deciduous, 3) Oaks (Mixed Quercus spp.), 4) Korean red pine, 5) Korean red pine and oaks, 6) ash, 7) mixed mesophytic, 8) subalpine zone coniferous, and 9) miscellaneous forest. Forests grouped within the subalpine zone coniferous and miscellaneous classifications were characterized by similar environmental conditions and those forests that did not fit in any other category, respectively.

• Archives of Pharmacal Research
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• 제11권1호
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• pp.45-51
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• 1988

The feature of resolution enhancement by derivative operation is linked to one of the multivariate analysis, which is multiple linear regression with two options, all possible and stepwise regression. Examined samples were synthetic mixtures of 5 vitamins, thiamine mononitrate, riboflavin phosphate, nicotinamide, pyridoxine hydrochloride and ascorbic acid. All components in mixture were quantified with reasonably good accuracy and precision. Whole data processing procedure was accomplished on-line by the development of three computer programs written in APPLESOFT BASIC language.

• 디자인학연구
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• 제19권5호
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• pp.255-268
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• 2006

본 연구에서는 '제품에 대한 사용자의 심리적 가치의식이 디자인 평가에 어떠한 작용을 하는가'에 문제의식을 제기하여 14가지의 제품 샘플을 대상으로 평가를 실시하였다. 이에 따른 주요내용은 '제품평가의 단계별 사고', '제품에 대한 가치의식', '조형이미지 생성과 디자인 평가' 등 크게 3가지 영역을 주요 골자로 하여 분석을 실시하였다. 결론 도출을 위해 먼저 4개의 연구가설을 설정하였고, 이를 검증하기 위하여 '종결적 조사'의 일환으로 사례연구를 실시하였다. 표본은 데이터의 정확성을 높이기 위하여 제품디자인을 전공으로 하는 20대 대학생 120명을 대상으로 선정하였다. 수집된 데이터는 '단순집계'에 의하여 전체적인 흐름을 파악하였고, 이를 토대로 3개의 평가항목에 대한 구체적인 분석을 실시하였다. 분석방법은 '요인분석(factor analysis)', '클러스터분석(duster analysis)' 등 '다변량분석(multivariate analysis)'에 의한 '정량적 분석'에 중점을 두었다. 본 연구의 실증분석은 유의수준 p<.05에서 검증하였고, 통계처리는 'SPSSWIN 12.0' 프로그램을 사용하였다. 그 결과 '제품에 대한 사용자의 가치의식에 따른 디자인 평가의 유형'에 관해 4가지 결론을 얻었다.

• Journal of the Korean Data and Information Science Society
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• 제19권4호
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• pp.1201-1210
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• 2008

The goal of this paper is to investigate the trend of stream quality and the quality of water in Nakdong river by the method of factor analysis. It used the fourteen different monthly time series data such as pH, BOD, COD, SS, TN and etc. of the thirty four of Nakdong River measurement points from Jan. 1998 to Dec. 2006. The result of factor analysis is that the factor 1 results from organic water pollution is occupied 29.288% such as BOD, COD, TN and EC, and the factor 2 explained from sewage and a seasonal variation is occupied 16.467% such as SS.

• Smart Structures and Systems
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• 제14권3호
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• pp.377-395
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• 2014

Vibration-based fault detection and condition monitoring of rotating machinery, using statistical process control (SPC) combined with statistical pattern recognition methodology, has been widely investigated by many researchers. In particular, the discrete wavelet transform (DWT) is considered as a powerful tool for feature extraction in detecting fault on rotating machinery. Although DWT significantly reduces the dimensionality of the data, the number of retained wavelet features can still be significantly large. Then, the use of standard multivariate SPC techniques is not advised, because the sample covariance matrix is likely to be singular, so that the common multivariate statistics cannot be calculated. Even though many feature-based SPC methods have been introduced to tackle this deficiency, most methods require a parametric distributional assumption that restricts their feasibility to specific problems of process control, and thus limit their application. This study proposes a nonparametric multivariate control chart method, based on multiscale wavelet scalogram (MWS) features, that overcomes the limitation posed by the parametric assumption in existing SPC methods. The presented approach takes advantage of multi-resolution analysis using DWT, and obtains MWS features with significantly low dimensionality. We calculate Hotelling's $T^2$-type monitoring statistic using MWS, which has enough damage-discrimination ability. A bootstrap approach is used to determine the upper control limit of the monitoring statistic, without any distributional assumption. Numerical simulations demonstrate the performance of the proposed control charting method, under various damage-level scenarios for a bearing system.

• Geomechanics and Engineering
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• 제21권6호
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• pp.583-598
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• 2020

This study is attempted to propose a new hybrid artificial intelligence model called integrative genetic algorithm with multivariate adaptive regression splines (GA-MARS) for settlement prediction of shallow foundations on sandy soils. In this hybrid model, the evolution algorithm - Genetic Algorithm (GA) was used to search and optimize the hyperparameters of multivariate adaptive regression splines (MARS). For this purpose, a total of 180 experimental data were collected and analyzed from available researches with five-input variables including the bread of foundation (B), length to width (L/B), embedment ratio (D_f/B), foundation net applied pressure (q_net), and average SPT blow count (N_SPT). In further analysis, a new explicit formulation was derived from MARS and its accuracy was compared with four available formulae. The attained results indicated that the proposed GA-MARS model exhibited a more robust and better performance than the available methods.