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$p^{n-m}$ fractional Factorial Design Excluded SOme Debarred Combinations
Choi, Byoung-Chul,Kim, Hyuk-Joo 한국통계학회 2000 Communications for statistical applications and me Vol.7 No.3
In order to design fractional factorial experiments which include some debarred combinations, we should select defining contrasts so that those combinations are to be excluded. Choi(1999) presented a method of selectign defining contrasts to construct orthogonal 3-level fractional factorial experiments which exclude some debarred combinations. In this paper, we extend Choi's method to general p-level fractional factorial experiments to select defining contrasts which cold exclude some debarred combinations.
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崔秉喆 全北大學校 1995 論文集 Vol.39 No.-
Choi(1993) proposed a multi-level skip-lot sampling plan(MLSkSP1), which has merits that we can freely choose not only the number, i, of consecutive lots to be accepted but also the fraction, f, of lots to be inspected. It has seen that the plan MLSkSP1 are desirable in the aspect that it can reduce the cost of inspection when the level of submitted quality is high. This paper presents two tables for 2-level and 3-level skip-lot sampling plants of Choi's MLSkSP1. In the tables, sample sizes, acceptable quality levels and lot tolerance percent defectives are calculated to control the vendor's risk by 0.05 and the consummer's risk by 0.10 for given numbers i and fractions f.
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김범철,최광순,김철구,이유희,김동섭,박제철 江原大學校 附設 環境硏究所 1998 環境硏究 Vol.15 No.-
Seasonal and vertical distributions of dissolved and particulate organic carbon were investigated from May 1995 to March 1997 in n deep mesotrophic reservoir, Lake Soyang, POC contentrations at the dam site ranged from 0.1 to 1.8 mgC/L and DOC concentrations ranged from 1.4 to 4.9 mgC/L. POC concentrations in the surface layer were higher in the season of cyanobacterial bloom, July to September. High POC was observed at the depth of 30 to 60m after storm runoff in summer monsoon season. Turbid storm runoff formed intermediate current laden with much particulate materials from terrestrial sources. The vertical and seasonal variation of DOC was smaller than POC. Higher DOC was observed near the lake bottom which implies sedimentation and degradation of much organic detritus at the bottom. The ratio of DOC : POC varied from 2 to 60, and the ratio was lowest in September 1995 when algal density was highest. DOC : POC ratio of the main inflowing river, the Soyang River, varied from 1 to 10, and the ratio was low in storm runoff when the POC concentration was high.
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노숙인 생활시설 종사자의 감정노동이 소진과 이차외상스트레스에 미치는 영향: 슈퍼비전의 조절 효과
최철 ( Choi¸ Chul ),장수미 ( Jang¸ Soo Mi ),정지형 ( Jeong¸ Ji Hyeong ) 한국보건사회연구원 2020 保健社會硏究 Vol.40 No.4
노숙인 생활시설 종사자와 같은 휴먼 서비스직은 감정노동의 강도가 높으며, 감정노동은 종사자의 소진과 이차외상스트레스에 영향을 미치는 것으로 알려져 있다. 본 연구의 목적은 노숙인 생활시설 종사자의 감정노동이 소진, 이차외상스트레스에 미치는 영향과 보호 요인으로서 슈퍼비전의 조절 효과를 검증하는 것이다. 연구 대상자는 전국32개 노숙인 생활시설 종사자로서, 218명의 자기 보고식 설문조사 결과를 자료 분석에 사용하였다. 위계적 회귀분석을 통한 주요 연구 결과는 다음과 같다. 노숙인 생활시설 종사자의 감정노동은 소진과 이차외상스트레스에 유의미한 영향을 미쳤으며, 슈퍼비전의 조절 효과가 검증되었다. 즉, 슈퍼비전은 노숙인 생활시설 종사자의 감정노동이 소진과 이차외상스트레스에 미치는 영향을 완충하는 것을 알 수 있다. 주요 결과를 토대로 노숙인 생활시설에서 슈퍼비전 체계의 필요성 및 안정적인 운영을 위한 논의를 하였다. Human service workers working at homeless shelters have been known to experience a high level of emotional labor, which could have effect on the burnout and secondary traumatic stress (STS) of them. This study examined (1) emotional labor affecting on the burnout and STS, and (2) the moderating effect of supervision as a protective factor. We collected data from homeless shelter workers (n=218) at 32 agencies using a self-reported paper-pencil survey. Hierarchical regression analysis were conducted to verify the moderating effect of supervision, Major results were as follows. We found a significant effect of emotional labor on the burnout and STS (β=.484, p<.01, β=.544, p<.01) and a significant moderating effect of supervision (β=-.216, p<.01, β=-.103, p<.05). The results suggest that supervision is an important modifiable variable for burnout and STS especially in homeless shelter workers with high level of emotional labor. Based on the results, we discussed the necessity of supervision system and its successful management in homeless shelters.
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이철우,최성수,최필선,이상협,이길철,박광식 한국환경독성학회 1997 환경독성보건학회지 Vol.12 No.2
Furfural, an organic solvent, is widely used as synthetic component material in producing chemical products. However, furfural has been reported that it shows strong toxicities to human being showing intense stimulus to skin, eyes, mucous membrane and nerve system. It is also known to cause anemia, liver cirrhosis, kidney failure and genetic toxicity in the human being working in the exposed area. LD50 of furfural for peritoneal injected mouse has been known around 20mg/kg, but the acute toxicity on aquatic organisms such as fish, daphnid or algae are not well known, compared to those on rodents. In this experiment, we studied on the fish toxicity of furfural using Japanese Meclaka (Oryzias latipes) and Common Carp (Cyprinus carpio). We also observed histological changes in the fish organs. The LC50s were 12.8 mg/L in Japanese Medaka and 21.8 mg/L in Common Carp, respectively. When Common Carps were exposed to 120 mg/L of furfural concentration for 30 minutes, blood congestion in gills and lysis of secondary lamella were shown. Though the muscle of caudal fin was not completely eroded, its epidermic cells were shown to be necrotic in various parts. Tissue atrophy and cell necrosis were also shown in the liver of Common Carps exposed to furfural. From these results, furfural seems to cause histological damages on liver, an internal organ as well as on external organs such as gills and fins eventhough the fish were exposed for a short-term.
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Young-Chul Kim,Hyun-Hee Chae,Sang-Heock Oh,Seung-Ho Choi2,Moon-Pyo Hong3,Gi-Heum Nam,Jae-Yoon Choi,Hyun-Sook Choi,Kyu-Song Lee 한국환경생태학회 2015 한국환경생태학회지 Vol.29 No.2
Yongneup wetland protected area, the only high moor in Korea, is a core area to conserve biodiversity. Even though the Yongneup wetland protected area is relatively small, various plant species are distributed in the Yongneup wetland protected area because it includes various habitats showing different environmental gradients. Vascular plants distributed in the Yongneup wetland protected area were identified as a total of 376 taxa that is composed of 73 families, 217 genera, 322 species, 3 subspecies, 44 varieties and 7 forms. For endangered plants designated by the Ministry of Environment, 5 species including Trientalis europaea var. arctica, Lilium dauricum, Halenia corniculata, Lychnis wilfordii and Menyanthes trifoliata were found and 34 taxa were confirmed to be distributed only in the mountainous wetland habitats. Regarding naturalized plants, a total of 11 taxa were distributed, but most of them were distributed in the areas where artificial interference has occurred. And in areas inside the wetlands that are relatively well preserved, 2 species of Bidens frondosa and Erigeron annuus were observed. In this study, the occurrence and distribution of Pseudostellaria baekdusanensis M. Kim, which was recently found in Mt. Baekdu and reported as a new species, were identified in the Yongneup wetland protected area. A wetland is a very vulnerable area to drastic environmental changes and damages to its ecosystem could cause the extinction of rare plant species which are distributed only in the wetlands. Therefore, it is mandatory that current status of the Yongneup wetland protected area is evaluated and actions to prevent rapid environmental changes are taken. Fourteen separate investigations were conducted in 2013 and another four in 2014, to evaluate current status of the Yongneup wetland protected area. These investigations have provided us the basic information for future actions of conservation and restoration.
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자동영상추적장치를 이용한 카드뮴 처리 Oryzias latipes의 행위독성연구
류지성,이철우,최필선,최성수,류홍일,이길철,정규혁,박광식 한국환경독성학회 1999 환경독성보건학회지 Vol.14 No.4
Changes in certain fish behaviors are known to be very sensitive indicators of sublethal exposure to environmental contaminants. Therefore, behavioral toxicity tests, if properly designed, can be very useful to assess the influence of hazardous chemicals on fish. However, quantitative analysis of xenobiotic -mediated changes in locomotor behavior in fishes are rare, due mainly to the methodological difficulties. In general, fish movement has been known to be hypertrophic or hypotrophic according to the chemicals. As a study of fish behavioral toxicities, we quatified the swimming movement of Orydas latipes using computer-automated video tracking system. Oryzias latipes was exposed to cadmium of 128 mg/L for 1 hour in a limited aquaria, then the total swimming distance, the average swimming velocity, the histogram of turning angles, and the turning frequency were analyzed. Fish treated with cadmium showed decreased swimming activities, decreased velocity, and decreased turning frequency, which means hypotrophic activity. From these results, the computer-automated video tracking system of this study seems to be a good tool for the evaluation of the potential ecotoxicological studies.
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최성희,박철진,오성기 경희대학교 부설 식량자원개발연구소 1992 硏究論文集 Vol.13 No.-
The objective of this study was to investigate the physicochemical characteristics of binary and ternary oil systems. Materials used in this experiment were four edible oils i. e. sesame, soybean, red-pepper seed and Sancho (Zanthoxylum schinifolium) seed oils. The physicochemical properties of mixed oils, as well as the inductive period of oxidation, were measured. The results obtained are as follows : 1. The optimum mixing ratios of sesame oil with each of soybean, red-pepper seed and Sancho seed oils, which still maintained a characteristic sesame oil flavor, were 1 : 3,1 : 0.5 and 1 : 0.5, respectively. 2. Sesame, soybean and red-pepper seed oils showed low acid and peroxide values. In contrast, however, Sancho seed oil showed the very high values, and acid, peroxide and TBA values were 17. 4, 28.6 and 1.8, respectively, Among the oils, soybean oil gave the longest induction period of oxidation and Sancho seed oils the shortest, and the induction period was increased in order of Sanch seed, red-pepper seed, sesame and soybean oils. 3. Binary oil system such as a mixed oil of seasame oil and each of soybean and red-pepper seed oils did not show any significant change in acid, peroxide and TBA values, but a mixed oil of sesame oil and Sancho seed oils gave a drastic change in acid (7.2), peroxide (12.3), and TBA (0.2) values. All the binary oil systems extended their induction periods of oxidation. 4. In ternary oil system, a mixed oil of sesame, soybean and red-pepper sees oils did not show any significant change in acid and peroxide values. In contrast, however, mixed oils of sesame, red -pepper seed and Sancho seed oils in the ratios of 1 : 1 : 1 and 4.5, 8.9 and 0.13 in the ratio of 1 : 0.25 : 0.25, respectively. All the ternary oil systems also extended the induction period of oxidation.
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