• 수산경영론집
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• 제46권2호
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• pp.111-125
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• 2015

This study is to analyze the efficiency of Korean sea food manufacturing using Data Envelopment Analysis. Firstly, based on an output oriented traditional CCR, BCC model, the study estimated the efficiency scores. The average estimates of technical, pure technical, and scale efficiency turned out 0.6517, 0.7184, 0.9074 respectively, which are separated for 50 marine corporations. The 10 DMUs were efficient under CCR model while the 17 DMUs under BCC model. Also, the study suggested that the operating profit of the two output factors should be more increased relatively and averagely from the viewpoint of efficiency improvement. Secondly, super efficiency scores are estimated under super efficiency and SBM model. As a result, it came to be possible to distinguish and rank the efficiency of the efficient DMUs. The highest score was 4.2975 under Super-CCR, was 2.4947 under Super-BCC, was 2.7160 under SBM-Super-CCR, and was 1.5319 under SBM-Super-BCC model. The average estimates of super efficiency were 0.76 and 0.82 under Super-CCR and Super-BCC model respectively, and were 0.61 and 0.67 under SBM-Super-CCR and SBM-Super-BCC model. Finally, the study conducted a rank-sum test, Wilcoxon-Mann-Whitney test, to find a statistical significance of heterogeneity existing in efficiencies among the sample corporations. The result showed that there was a significant difference in average efficiency between Dried, Salted product manufacturing and Frozen product manufacturing under BCC-Super efficiency model at 10% level of significance. Furthermore, TOBIT model was applied to find out the potential factors that might influence the efficiency, Wilcoxonand the results showed debt and sales cost influenced all of the technical, pure technical, and scale efficiency, while net profit influenced only the technical efficiency.

• 수산해양기술연구
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• 제50권1호
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• pp.83-88
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• 2014

A new shell divider was manufactured according to the principle of the lever in order to improve working efficiency in collecting the gonad of Sea Urchin, Anthocidaris crassispina, around the coast of jeju. It was composed of three parts of a pair of handles for grasping power, a fulcrum and a pair of knives for action with 21cm in length and 13cm in width. The operating efficiency of the shell divider was tested out in three place of Jeju coast. Statistical significances of differences of working time between test groups were calculated according to the t-test with the level of significance. In dividing the shell of sea urchin, the average of about 3 seconds of working time by the shell divider was less than that by a knife. At the result of t-test, the statistical significance in the working time existed between the divider group and the knife group. On the other hand, the working time among the divider operators showed no significant differences. It is concluded that the shell divider is more efficient than a knife in traditional operating.

• 한국농공학회논문집
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• 제52권5호
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• pp.27-35
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• 2010

The characteristics of delivered nutrient loads were analyzed and the regression equations to estimate delivery ratios of nutrients (TN and TP) were developed using HSPF simulation results at six subwatersheds within the Bochung A unit watershed during 1998-2007. TN delivery ratio was higher than TP delivery ratio because significant amounts of TP was considered to be attached at soil as ${PO_4}^-$ during delivery process from discharged point of nutrient source to main stream. As a results of correlation analysis, factors related to geomorphic characteristics had not statistical correlation with TN and TP delivery ratios. TN loading rate from living and specific stream flow had statistical negative and positive correlation, respectively, with TN delivery ratio. TP loading rates from all sources and from land cover and specific stream flow had statistical negative, negative and positive correlation, respectively. The specific stream flow represents the most strong correlation with nutrient delivery ratios. The regression equations to estimate delivery ratios for TN and TP were developed by including statistical correlated factors and showed high efficiency of 0.98 and 0.95 of coefficient of determination for TN and TP, respectively.

• 한국조사연구학회:학술대회논문집
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• 한국조사연구학회 2000년도 춘계학술대회 조사연구의 방법론적 쟁점
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• pp.137-159
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• 2000

지식 정보화 사회에서 필요한 통계는 "기술통계+추론통계+실용통계"의 특성을 갖추어야 하며 적시성, 정확성과 경제성을 갖는 통계를 생산하기 위해서 자료 수집과 분석 과정에서 컴퓨터를 이용해 왔으나, 앞으로 인터넷이 보편화된 사이버 공간 사회에서 활용될 수 있는 실용통계 생산에 역점을 둔 통계 발전 방안을 살펴보았다. 먼저 컴퓨터 보급과 이용 현황을 살펴보고 컴퓨터 이용 조사 기법의 발달 과정을 요약하였으며, 적용 사례 중심으로 인터넷 조사의 발전 가능성에 대해서 언급한 후에, 모든 분야에서 어떤 종류의 통계도 효과적으로 생산할 수 있는 컴퓨터 이용 통계 조사 종합 시스템을 제안하였다.스템을 제안하였다.

• 한국조사연구학회지:조사연구
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• 제1권2호
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• pp.137-159
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• 2000

지식 정보화 사회에서 필요한 통계는 “기술통계+추론통계+실용통계”의 특성을 갖추어야 하며 적시성, 정확성과 경제성을 갖는 통계를 생산하기 위해서 자료 수집과 분석 과정에서 컴퓨터를 이용해 왔으나, 앞으로 인터넷이 보편화된 사이버 공간 사회에서 활용될 수 있는 실용통계 생산에 역점을 둔 통계 발전 방안을 살펴보았다. 먼저 컴퓨터 보급과 이용현황을 살펴보고 컴퓨터 이용조사 기법의 발달 과정을 요약하였으며, 적용 사례 중심으로 인터넷 조사의 발전 가능성에 대해서 언급한 후에, 모든 분야에서 어떤 종류의 통계도 효과적으로 생산할 수 있는 컴퓨터 이용 통계 조사 종합 시스템을 제안하였다.

• Communications for Statistical Applications and Methods
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• 제30권4호
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• pp.389-402
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• 2023

Multivariate or clustered failure time data often occur in many medical, epidemiological, and socio-economic studies when survival data are collected from several research centers. If the data are periodically observed as in a longitudinal study, survival times are often subject to various types of interval-censoring, creating multivariate interval-censored data. Then, the event times of interest may be correlated among individuals who come from the same cluster. In this article, we propose a unified linear regression method for analyzing multivariate interval-censored data. We consider a semiparametric multivariate accelerated failure time model as a statistical analysis tool and develop a generalized Buckley-James method to make inferences by imputing interval-censored observations with their conditional mean values. Since the study population consists of several heterogeneous clusters, where the subjects in the same cluster may be related, we propose a generalized estimating equations approach to accommodate potential dependence in clusters. Our simulation results confirm that the proposed estimator is robust to misspecification of working covariance matrix and statistical efficiency can increase when the working covariance structure is close to the truth. The proposed method is applied to the dataset from a diabetic retinopathy study.

• 한국지하수토양환경학회지:지하수토양환경
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• 제23권1호
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• pp.14-24
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• 2018

In soil washing, there are many variables including types of reagent and contaminant, washing time, soil-liquid ratio, washing cycles, washing agent concentrations, and etc. To identify the most influencing factors on soil washing process, regression analysis was performed for eight single variables and five combined variables. A quantitative model that employs W/H (molar ratio of washing agent to heavy metal) as a major variable was established based on the regression. The validity of the model was demonstrated by conducting lab experiments with Cu, Pb, Zn, Ni and As-contaminated soils, and various washing reagents including acetic acid, citric acid, malic acid, oxalic acid, ethylenediamine tetraacetic acid (EDTA) and nitriloacetic acid (NTA). The washing efficiencies were compared with the EDTA washing data reported in the literature. The correlation between W/H and removal efficiency was analyzed after dividing data into two groups according to the heavy metal mobility.

• Journal of the Korean Statistical Society
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• 제33권4호
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• pp.411-433
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• 2004

The shrinkage preliminary test ridge regression estimators (SPTRRE) based on Wald (W), Likelihood Ratio (LR) and Lagrangian Multiplier (LM) tests for estimating the regression parameters of the multiple linear regression model with multivariate Student's t error distribution are considered in this paper. The quadratic biases and risks of the proposed estimators are compared under both null and alternative hypotheses. It is observed that there is conflict among the three estimators with respect to their risks because of certain inequalities that exist among the test statistics. In the neighborhood of the restriction, the SPTRRE based on LM test has the smallest risk followed by the estimators based on LR and W tests. However, the SPTRRE based on W test performs the best followed by the LR and LM based estimators when the parameters move away from the subspace of the restrictions. Some tables for the maximum and minimum guaranteed efficiency of the proposed estimators have been given, which allow us to determine the optimum level of significance corresponding to the optimum estimator among proposed estimators. It is evident that in the choice of the smallest significance level to yield the best estimator the SPTRRE based on Wald test dominates the other two estimators.

• 상하수도학회지
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• 제31권4호
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• pp.289-296
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• 2017

Pulp and paper industry produces large volumes of wastewater and residual sludge waste, resulting in many issues in relation to wastewater treatment and sludge disposal. Contaminants in pulp and paper wastewater include effluent solids, sediments, chemical oxygen demand (COD), and biological oxygen demand (BOD), which should be treated by wastewater treatment processes such as coagulation and biological treatment. However, few works have been attempted to predict the treatment efficiency of pulp and paper wastewater. Accordingly, this study presented empirical models based on experimental data in laboratory-scale coagulation tests and compared them with statistical models such as artificial neural network (ANN). Results showed that the water quality parameters such as turbidity, suspended solids, COD, and UVA can be predicted using either linear or expoential regression models. Nevertheless, the accuracies for turbidity and UVA predictions were relatively lower than those for SS and COD. On the other hand, ANN showed higher accuracies than the emprical models for all water parameters. However, it seems that two kinds of models should be used together to provide more accurate information on the treatment efficiency of pulp and paper wastewater.

• 전자공학회논문지C
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• 제35C권10호
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• pp.38-47
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• 1998

실용적인 기계번역 시스템을 위한 구문 분석은 긴 문장의 분석을 허용하여야 하는데 긴 문장의 분석은 높은 분석의 복잡도 때문에 매우 어려운 문제이다. 본 논문에서는 긴 문장의 효율적인 분석을 위해 문장을 분할하는 방법을 제안하며 통계 정보와 유전자 학습에 의한 최적의 문장 분할 위치 결정 방법을 소개한다. 문장 분할 위치의 결정은 분할 위치가 태그된 훈련 데이타에서 얻어진 어휘 문맥 제한 조건을 이용하여 입력문장의 분할 가능 위치를 결정하는 부분과 여러 개의 분할 가능 위치 중에서 안전한 분할을 보장하고 보다 많은 분석의 효율 향상을 얻을 수 있는 최적의 분할 위치를 학습을 통해 선택하는 부분으로 구성된다. 실험을 통해 제안된 문장 분할 위치 결정 방법이 안전한 분할을 수행하며 문장 분석의 효율을 향상시킴을 보인다.