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퇴적토 내 납(Pb) 오염 농도 추정을 위한 다변량 통계 기법
이선재,송서영,이해석,최재영 한국퇴적환경준설학회 2023 한국환경준설학회 학술대회논문집 Vol.2023 No.11
하천 및 호소에 존재하는 퇴적토의 중금속 오염은 자연발생적 또는 폐기물투기와 제강산업 등의 인위적 요인에 의해 발생한다. 특히, 납(Pb)은 신경독성물질로써 고농도로 오염될 수 있는 원소 중 하나이며, 수생태계 및 인간 건강에도 부정적인 영향을 끼칠 수 있다. 납은 미세 퇴적토 및 유기물과 복합체를 형성할 수 있으며, 결합력은 pH와 유기물 함량과 높은 상관관계를 갖는 것으로 알려져 있다. 본 연구에서는 퇴적토 내에 존재하는 Pb의 오염 농도를 추정하기 위해 다변량 통계 기법을 적용하였다. 적절하게 채취된 퇴적토를 왕수 추출법을 이용해 전함량을 분석했으며, SCIP (Sample core induced polarization) tester를 통해 퇴적토의 전기적 특성(전기비저항, 유도분극)을 측정하였다. 수집된 지구화학적, 지구물리학적 데이터를 통계 기법인 다변량 통계 분석을 실시하였으며, 서로 다른 영역의 데이터 간의 인과관계를 해석하고 회귀식을 도출하였다. 도출된 회귀식을 바탕으로 전기적 특성에 기반한 Pb 오염 농도를 추정 및 검증을 수행하였다.
이선재,장중순,유찬세,김종호,박상철 한국신뢰성학회 2021 신뢰성응용연구 Vol.21 No.3
Purpose: The gamma process was used to predict the remaining useful life of a bipolar junction transistor, which is a widely used electronic component. Methods: The proposed method consists of six major steps: 1) data collection via accelerated degradation test, 2) data conversion for the gamma process, 3) parameter estimation of the gamma process, 4) shape function estimation using a fitting procedure, 5) degradation model generation using the inverse power law and Arrhenius relation, and 6) prediction of the remaining useful life by estimating the failure criterion. Results: The degradation characteristic of a bipolar junction transistor is the beta (β) value (current gain), and the transistor is considered a failure when the β value deteriorates by 33.3%. Conclusion: This paper proposes a new method for predicting the remaining life of a bipolar junction transistor.
소비자의 의류상점선택기준에 따른 시장세분화와 마케팅전략
이선재,장은영 한국의류학회 1992 한국의류학회지 Vol.16 No.4
The purpose of this study was 1) to find out Market segmentation possibilities according to consumer's store selection factors by analysis of Consumer's attitude and criteria of apparel store selection, 2) to provide marketing strategies of segment marker for apparel stores Research problems were as follows. 1) To find out the important factors of consumer's store selection and to segment markets according to their factors. 2) To find. out consumer characteristics (demographic variables, clothing life factors, clothing purchase behaviors) according to segment markets. 3) To find out preference store types and preference factors according to segment markets. 4) To provide marketing mix strategy for retail apparel store sales. The subjects selected for the final analysis were 586 female college students, housewives, and workers living in Seoul. A questionnaire was developed in order to measure consumer's selection criteria of apparel store, consumer characteristics and preferred store types and preferential factors. The results of this study were as follows: 1. There were 8 factors of consumer's store selection such that: the high quality, convenience, store atmosphere, economy, dependency commercials, store patronage, the conformity, product assortment. the result of cluster anaysis based on these 8 factors of store selection verified that market was able to be segmented as four different market, which were the store loyalty group, the aligned economical group, the assortment pursuing group, the store fame dependent group. 2. There were significant differences among four groups, for 4 variables related to consumer' s characteristics such as demographic characteristics (sex, age, job, level of education, the living quarters, marrige or unmarrige), clothing life factors, clothing evaluating criteria, and favorite fashion information sources. 3. There were significant differences among four groups for 2 variable related to store preference such as preference types of store and preference factors of store.
인 수준이 다른 육계사료에 Crude Phytase 첨가시 생산성에 미치는 영향
이선재,엄재상,백인기,이재관 한국가금학회 2000 韓國家禽學會誌 Vol.27 No.3
An experiment was conducted to measure the effect of crude phytase supplementation on the growing performance, blood concentrations of some minerals and tibia characteristics of broiler chickens. Day-old 240 male broiler chickens (Avian) were randomly allotted to four treatments. There were six replicates per treatment, and ten chicks per replicate. Treatments consisted of two levels of crude phytase (0 and 600U/kg) made from Aspergillus ficuum and two levels of non-phytate P (0.45 and 0.35% NPP for the starter period, and 0.35 and 0.25% NPP for the grower period), making the experiment 2$\times$2 factorial. The starter period was from hatch to 21 d of age, and grower period was from 22 to 35 d of age. Feed intake and weight gain of chicks fed diet containing phytase were higher(P〈0.05) than those of chicks fed diets without phytase, however, no differences was found in feed/gain. mortality, and nutrient availabilities regarding the phytase supplementation. Chickens fed diets with low NPP and phytase excreted lower P than did birds fed diets containing normal NPP without phytase. The level of NPP and phytase did not affect N excretion. The Ca availability was increased by feeding low NPP diet. Dietary phytase increased the availabilities of P and Mg, but decreased those of Fe and Zn. There was interactions between dietary NPP level and phytase addition on mineral availability. Tibia was lighter and shorter in low NPP groups, and heavier in phytase treated groups. The tibial contents of Ca, P and Mg decreased in low NPP treated groups, but increased in phytase treated groups. The ash content of tibia of chickens fed diet with phytase was higher than that of birds fed diets without phytase. These data suggest that the crude phytase supplementation to broiler diets containing low NPP level improves growth performance and mineral availability and, reduces fecal P excretion.