• 응용통계연구
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• 제31권4호
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• pp.463-473
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• 2018

연구에서는 선형회귀모형을 가정한 대형 데이터에서의 변수선택 알고리즘을 다룬다. 방법의 속도와 강건성에 주안점을 둔 여러 알고리즘들이 제안되었다. 그 중에서 streamwise 회귀 접근법을 사용한 VIF회귀는 신속하고 정확하게 수행된다. 그러나 VIF회귀는 최소제곱방법에 의해 모형이 추정되므로 이상치에 민감하다. 변수선택방법의 강건성을 높이기 위해 가중 추정치를 사용한 강건측도가 제안되었으며 강건 VIF회귀도 제안되었다. 본 연구에서는 잠재적 이상치를 탐지하여 제거한 후 VIF회귀를 수행하는, 빠르고 강건한 변수선택 방법을 제안한다. 제안된 방법은 모의실험과 데이터 분석 통해 다른 방법들과 비교된다.

• KIEAE Journal
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• 제15권6호
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• pp.5-10
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• 2015

Purpose: To evaluate the economic performance of grid-connected photovoltaic system in residential house, household electricity bill policy of Korea Electric Power Corporation (KEPCO) must be applied precisely, and market tendency and uncertainty of system also need to be considered. In this study, to evaluate the economic feasibility of PV system, we measured PV power generation and electricity consumption of six of Green home in Daejeon through web based remote monitoring system. Method: We applied Monte-Carlo simulation based on life cycle cost analysis, to reflect an uncertainty of main factor in economic feasibility evaluation of photovoltaic system. Result: First, with deterministic analysis, the difference of NPV of cumulative financial savings among households varied from -3,310 ~ 24,170 thousand won, portraying notably big range. Also the possibility of getting the same result was 50% when applying uncertainty. Second, the higher electricity consumption is, the more economic feasibility of photovoltaic system increases because KEPCO uses progressive taxation in household electricity bill policy. Third, The contribution to variance of electricity price increases in NPV varied from 98.5% to 99.9%. While the inflation rate and annual degradation contributed very little to none.

• 한국자원식물학회지
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• 제6권2호
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• pp.141-145
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• 1993

Apexes of basidia in Rhodophyllus(synonyum of Entoloma) muraii var. albus are divided into four sections or depressed in the center. A spore is formed by inflation of the apex of the sterigma. The apex of the sterigma is swollen and changed from a papilla through a penisform and a club into a globeform. Six spots of globose spore are regularly or irregularly depressed with hilum axes. Finally the spores are cuboid. Basidia of Entoloma squamiferrum are developed from hymenium layer of crator-shaped parabasidium. Apex of basidium is flat or depressed in the center. Although four sterigmata are developed, only two sterigmata are symmetrically swollen to two spores in certain basidia. It means that two sterigmata among four sterigmata are infertile. The apex of the sterigma is swollen into a paillaform, and then turned into a penisform. It is swollen from a clubform into a globeform. Six spots of the surfaces of globose spore are deperssed with hilum axes. Finally the spore is cuboid, and then it is released from hilum. Four sterigmata of papillaform of E. violaceobrunneum are developed from cartor-shaped basidium. The apex of sterigma is swollen to a small globeform. And then it is swollen to a clubform. The clubform is again swollen to a ellipticalform, and then more than six spots of spore surfaces are ramomly depressed with hium axes. When the depression of surface of a elliptical spore is over, it is the multi-angular spore of the heterometrical-form.

• 대한가정학회지
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• 제41권9호
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• pp.105-120
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• 2003

This study has conducted to develop the computer program for households portfolio management to enhance their financial well-being. The study has divided into two parts. First, descriptive statistics has used to analyze as a basis of computer program and it includes the comparison of household asset allocations between households in Korea and U. S. A., Second, it shows the components of the portfolio program developed to manage households efficiently. For both two countries, recent four years data has been used and in part two, total sample size of households in Korea is 2155. From the statistical analysis, households in U. S. A. tend to invest more on the stock & bonds as their net-asset is increased. However households in Korea tend to have less financial assets and it might be found the fact that they prefer to own real-estate because of the inflation. In the part of computer program, it is included the average financial asset responding to the demographic variables and households could refer those average amount as a reference planning their asset portfolio.

• 한국어병학회지
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• 제20권3호
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• pp.257-267
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• 2007

The hypo-salinity effects on fertilized eggs, embryos and larvae were investigated in olive flounder (Paralichthys olivaceus) obtained from hatcheries in Cheju-Island, Yeosu and Chungnam. Those were treated to eight concentration; 0, 3.4, 6.7, 10.1, 13.4, 20.2, 27.4 and 33.6 ‰. It was not discrepancy in the survival rate and hatching success rate of fertilized embryos obtained from different regions. Also, in the larvae, the regional difference was not appeared. The survival rate and hatching ability of embryos significantly diminished in the lower groups than 13.4 ‰ compared to 33.6 ‰. After fertilization, namely embryos are tolerant of a wide range of salinity (13.4 - 33.6 ‰). Reduced salinity induced an increase of the malformed embryo and larvae including various deformities; irregular embryos membrane (or yolk sac depression), fin erosion and swim bladder inflation in the flounder embryo. The hatching success of embryos was significantly reduced in lower salinity than 13.4 ‰. Notably, the reduction of larval survival rate significantly was observed in ≤10.1 ‰ treated groups with the same manner of survival rates of the embryos. Additionally, olive flounder was found to be adequate model for measuring external impulses because there are no the regional differences.

• 한국화재소방학회논문지
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• 제18권4호
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• pp.1-15
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• 2004

한국 미국ㆍ일본 3국의 화재로 인한 재산피해 분석을 통해 아래 사항을 확인하였다. ① 3국의 화재로 인한 재산피해통계 중 우리나라의 통계가 가장 구체적이지 않으며, 우리나라의 통계는 화재로 인한 재산피해의 실태를 정확히 분석하는데 많은 한계를 안고 있다. ② GDP에서 화재로 인한 재산피해가 차지하는 비율은 미국과 일본은 감소추세에 있으나 우리나라는 증가추세에 있으며 1994년도부터는 미국ㆍ일본과 지의 같은 비율을 차지하고 있다. ③ 인플레이션(소비자물가지수 기준)을 고려한 경우, 화재로 인한 재산피해는 일본과 미국은 감소하고 있으나 우리나라는 최근 2년을 제외하고는 증가추세에 있었다.

• 한국관광식음료학회지:관광식음료경영연구
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• 제9권
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• pp.213-242
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• 1998

Even in the best of economic environments, restaurants menu pricing is a serious concern to those in the food service industry. During times of rapid inflation, closer government regulation of compensation practices, and limited gains in worker productivity, the decisions regarding the proper charge for menu items become increasingly important. In addition to many operational and managerial factors, an important ingredient in the food service enterprise's success is its ability to meet the market by providing the value expected. The contribution-margin approach to pricing described above is familiar to cost accountants, who will also recognize that it admits of much elaboration before it can become a tool for day-to-day decisions. But the system probably has the greatest promise for multi-unit companies, where the cost benefit ratio of additional refinements improves in proportion to the number of operations. For example, the analysis required to specify the demand function better becomes less expensive if the findings can be applied to the pricing structure of numerous units. In any of its many adaptations, the essence of the integrated menu pricing system remains its ability to bring together the relevant revenues and costs with the operator's sense of the market and competitive environment to suggest prices that maximize profits.

• 한국정보통신학회논문지
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• 제6권7호
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• pp.1006-1012
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• 2002

본 논문에서는 북한의 통신 인프라 현대화 방향을 패. 내외적 여건에 대한 지역특성에 적합한 적용 가능한 면과 지역특성에 거하여 실현 가능한 통신망 현대화 전략을 제시하고자 한다. 따라서 모델링을 위한 대상 지역의 선정, 자료수집 및 선정된 지역의 특성 분석, 수요 및 트래픽 예측등 모델로 선정된 지역에 대한 종합적인 통신망 현대화 방안을 수립하여야 하나, 현재 북한은 전반적인 통신 인프라가 초기단계에 있기 때문에 위와 같은 상황을 모두 고려할 수 없음으로 기본적인 통신망 현대화 전략만을 고려하여 목표 년도의 개념적 통신망 구조를 설정하였다.

• 한국콘텐츠학회논문지
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• 제14권11호
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• pp.743-758
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• 2014

본 연구는 노인이 인지하고 있는 소득불평등과 자살생각 간 관계구조에서 경제적 스트레스의 매개효과를 검증하는데 그 목적이 있다. 이러한 연구목적을 달성하기 위해 전라남도에 거주하고 있는 65세 이상 노인 541명을 대상으로 조사한 자료를 이용하여, 노인들의 소득불평등 인식, 경제적 스트레스, 자살생각 정도 등에 대해 알아보았다. 분석은 SPSS ver. 18.0을 이용 기초통계, 신뢰도, 상관관계, 회귀분석(공차한계와 분산팽창지수) 등을 실시하였다. 분석 결과 조사 대상 노인들이 인지한 소득불평등과 자살생각 간 관계에서 경제적 스트레스의 매개효과가 있는 것으로 확인되었다. 이러한 결과를 바탕으로, 노인의 자살생각을 감소시키기 위한 실천적, 정책적 제언을 제시하였다.

• 한국도로학회논문집
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• 제16권5호
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• pp.133-142
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• 2014

PURPOSES : The objective was to develop the advanced method which could not explain each observation's specific characteristic in the present negative binomial method that results in under-estimation of the standard error(t-value inflation) and affects the confidence of whole derived results. METHODS : This study dealt with traffic accidents occurring within interchange segment on highway main line with RPNB(Random Parameter Negative Binomial) method that enables to take account of heterogeneity. RESULTS : As a result, AADT and lighting installation type on the road were revealed to have random parameter and in terms of other geometric variables, all were derived as fixed parameter(same effect on every segment). Also, marginal effects were adapted to analyze the relative effects on traffic accidents. CONCLUSIONS : This study proves that RPNB method which considers each observation's specific characteristics is better fitted to the accident data with geometrics. Thus, it is recommended that RPNB model or other methods which could consider the heterogeneity needs to be adapted in accident analysis.