• 제목/요약/키워드: case control

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전기조명 제어 전략에 따른 조명에너지 소비량 평가에 관한 연구 (A Study on the Evaluation of Lighting Energy Consumption by Control Strategy of the Electric Lighting)

  • 윤경;김강수
    • KIEAE Journal
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    • 제12권1호
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    • pp.119-125
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    • 2012
  • The objective of this study is to evaluate the electric lighting energy consumption carried out by Daysim program. A comparison between the measurement and simulated exterior global horizontal illuminance shows differences about 10% and it is very similar to the measurement. The interior illuminance simulated by Daysim are 18.9% lower than the measurement and simulated lighting energy consumption is 10% lower than the measurement. Corrected annual lighting energy simulation results show that the best case is the combination of occupancy switch-off and dimming system with automatic controlled blinds (E-3). In case of no blinds, it occasionally derives the minimum lighting energy consumption but it causes the glare, so we need to be careful for choosing the control strategy. For the overcast sky, the lighting energy consumption is not changed significantly by control strategy while the lighting energy in the clear sky is changed noticeably. So we must know the right strategy for each case to control the electric lights and blinds.

No Association between Egg Intake and Prostate Cancer Risk: A Meta-analysis

  • Xie, Bo;He, Huadong
    • Asian Pacific Journal of Cancer Prevention
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    • 제13권9호
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    • pp.4677-4681
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    • 2012
  • Objective: Egg consumption has been suggested to increase the risk of colorectal and some other cancers. The present study summarized and quantified the current evidence relating dietary intake of eggs and prostate cancer. Materials and methods: Literature searches were conducted to identify peer-reviewed manuscripts published up to July 2012. Twenty manuscripts from nine cohort studies and 11 case-control studies were identified. Summary risk estimates with 95% confidence intervals (CIs) were calculated for case-control and cohort studies separately. Results: Neither the case-control not the cohort studies showed any association of prostate cancer incidence with egg consumption (case-control studies: odds ratio 1.09, 95% CI 0.86-1.31; cohort studies: relative risk 0.97, 95% CI 0.97-1.07). The results were consistent in subgroup analysis. Furthermore, no association was observed between egg consumption and prostate cancer-specific mortality. Conclusions: Our analyses provided no evidence of a significant influence of egg consumption on prostate cancer incidence and mortality. However, more studies, particularly large prospective studies, are needed.

2단계 사례-대조자료를 위한 로지스틱 회귀모형의 추론 (Estimation of Logistic Regression for Two-Stage Case-Control Data)

  • 신미영;신은순
    • 응용통계연구
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    • 제13권2호
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    • pp.237-245
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    • 2000
  • 이 논문에서는 2단계 계획 하에서의 사례-대조 자료를 로지스틱 회귀 모형에 적합시키고 WESML방법으로 모수를 추정하며 추정량의 점근분포를 찾는다. 또한 WESML,방법과 CML 방법으로 얻은 모수의 추정량과 표준오차를 실제 자료를 이용하여 비교한다.

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Analysis of Nested Case-Control Study Designs: Revisiting the Inverse Probability Weighting Method

  • Kim, Ryung S.
    • Communications for Statistical Applications and Methods
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    • 제20권6호
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    • pp.455-466
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    • 2013
  • In nested case-control studies, the most common way to make inference under a proportional hazards model is the conditional logistic approach of Thomas (1977). Inclusion probability methods are more efficient than the conditional logistic approach of Thomas; however, the epidemiology research community has not accepted the methods as a replacement of the Thomas' method. This paper promotes the inverse probability weighting method originally proposed by Samuelsen (1997) in combination with an approximate jackknife standard error that can be easily computed using existing software. Simulation studies demonstrate that this approach yields valid type 1 errors and greater powers than the conditional logistic approach in nested case-control designs across various sample sizes and magnitudes of the hazard ratios. A generalization of the method is also made to incorporate additional matching and the stratified Cox model. The proposed method is illustrated with data from a cohort of children with Wilm's tumor to study the association between histological signatures and relapses.

Adaptive Immersion and Invariance Control of the Van der Pol Equation

  • Khovidhungij, Watcharapong;Santhanapipatkul, Ponesit
    • 제어로봇시스템학회:학술대회논문집
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    • 제어로봇시스템학회 2005년도 ICCAS
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    • pp.706-709
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    • 2005
  • We study the adaptive stabilization of the Van der Pol equation. A parameter update law is designed by the immersion and invariance method, and is used in conjunction with both the feedback linearization and backstepping control laws. Simulation results show that the responses obtained in the adaptive case are very similar to the known parameter case, and the parameter estimator converges to the true value.

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배추김치의 저장성에 미치는 감자 첨가의 영향 (Effects of Potato on the Storage of Kimchi)

  • 백재은
    • 한국식품영양학회지
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    • 제20권4호
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    • pp.421-426
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    • 2007
  • This study was carried out to investigate the properties of Kimchi made with potato as compared to Kimchi made with radish. The pH, acidity, hardness, and number of lactic acid bacteria were examined as properties of the Kimchi to determine the suitability of adding the potato and with focus on the possible duration of storage. First in the case of pH, the storage duration at pH $4.2{\sim}4.3$, which is the state for optimal tasting Kimchi, was approximately 10days in the control group, while that of the experimental group was 10 to 16 days, and thus, longer than the control. Second in the case of acidity, representing the maturity of Kimchi, we examined the time it took to reach 0.6% acidity, in which the experimental group took more longer time than the control. Although the experimental group was slower to mature than the control, the period for keeping at the proper pH was longer than that of the control group. Thirdly, in the case of hardness, which relates to softening, the experimental group had remarkably high values. This suggests that the Kimchi in the experimental group had a more rigid texture and more difficultly softening than the control group. Lastly in the case of the number of lactic acid bacteria, which closely relates to the process of fermentation, there were no significant differences. In conclusion, these results indicate that adding potato to Kimchi can extend its storage period.

歸脾湯 및 歸脾湯加味方의 止血效果에 관한 實驗的 硏究 (A Study on the Homostatic Effects of Guipitang and Guipitangjiaweifang Extracts in Experimental Animals)

  • 박인기;김경준
    • 한방안이비인후피부과학회지
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    • 제16권1호
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    • pp.63-76
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    • 2003
  • This Experiment was conducted to investigate the hemostatic effects of Guipitang and Guipitangjiaweifang. For this purpose, the effects of the crude extracts on the platelet count. prothrombin time, fibrinogen level and partial prothromboplastin time were estimated. The rats were divided into normal group, control group and experimental group. Control group was administrated normal saline and experimental group was divided into Sample 1 (Guipitang) and Sample 2 (Guipitangjiaweifang). The results obtained were as follows : 1. The platelet count was significantly increased in both of two samples as compared with the control group. 2. The prothrombin time was significantly shortened in case of Sample 2. however there were no significant changes in case of Sample 1 as compared with the control group. 3. The fibrinogen level was significantly increased in case of Sample 1. however there were no meaningful changes in case of Sample 2 as compared with the control group. 4. The partial prothromboplastin time was significantly shortened in both of two samples as compared with the control group. According to above results. it is supposed that Guipitang and Guipitangjiaweifang have the hemostatic effects in experimental animals.

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Circulating folate levels and colorectal adenoma: a case-control study and a meta-analysis

  • Park, Yeong Mi;Youn, Jiyoung;Cho, Chang Ho;Kim, Sung Hi;Lee, Jung Eun
    • Nutrition Research and Practice
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    • 제11권5호
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    • pp.419-429
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    • 2017
  • BACKGROUND/OBJECTIVES: The relationship between folate and colorectal neoplasia remains controversial. We examined the association between serum folate concentrations and colorectal adenomas in a case-control study of Korean adults and conducted a meta-analysis. SUBJECTS/METHODS: Our case-control study included 113 pairs of case and control who underwent colonoscopy and provided blood samples. We used multivariable conditional logistic regression models to obtain the odds ratios and 95% confidence interval (CIs). For meta-analysis, we identified the relevant studies by searching the PubMed database up to February 2017, included our case-control study and combined the study-specific relative risks (RRs) using a random-effects model. RESULTS: In this case-control study, we included 58 men and 55 women with colorectal adenomas and sex and fasting status matched the controls. We did not find any significant association between the serum folate levels and colorectal adenomas in either men or women. For meta-analysis, a total of eleven studies were included in our analysis and classified into two groups; polyp clearance group (PC) for the studies that included participants who underwent endoscopies and had their polyps removed at baseline; and no polyp clearance group (NPC) for the studies that included participants whose histories of endoscopies were unknown or who underwent their first endoscopies. Four PC (1,311 cases and 1,672 non-cases) and eight NPC studies (3,501 cases and 11,347 non-cases) were included. The combined RRs (95% CIs) comparing the bottom with the top categories of circulating folate levels were 1.07 (0.97-1.18) for the NPC group but 1.45 (1.16-1.74) for the PC group. CONCLUSIONS: Low circulating folate levels were associated with new adenoma formation.

분산성분모형 관리도의 설계와 효율 (Design and efficiency of the variance component model control chart)

  • 조찬양;박창순
    • Journal of the Korean Data and Information Science Society
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    • 제28권5호
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    • pp.981-999
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    • 2017
  • 단순확률모형을 고려하는 표준관리도에서는 표본간 분산을 고려하지 않고 공정분산을 추정한다. 표본간 분산이 존재하는 경우에는, 공정분산이 과소추정된다. 공정분산이 과소추정되면 좁아진 관리한계로 인해 관리도의 민감도는 향상되지만 과도한 오경보율을 발생시킨다. 이 논문에서는 공정모형으로 분산성분모형, 즉 변동의 원인을 표본내 분산과 표본간 분산으로 구분하는 확률모형을 고려한다. 관리한계는 표본내 분산과 표본간 분산을 모두 사용하여 설정하고 그에 따른 평균런길이를 통하여 효율을 살펴 보았다. 관리형태는 가장 널리 사용되는 ${\bar{X}}$, EWMA, CUSUM 관리도를 고려하였다. 관리한계 설정에서 표본내 분산만을 사용한 경우 (Case I)와 표본간 분산도 함께 사용한 경우 (Case II)를 통해 관리도의 효율을 비교하였다. 또한, 공정 모수가 주어진 경우와 추정된 두 경우에 대해서도 관리도의 효율을 비교하였다. 그 결과, 표본간 분산이 증가할 때 Case I의 오경보율은 급격히 증가한 반면 Case II의 경우에는 동일하게 유지됨을 알 수 있었다.

공단지역 일부 주민들의 주택유형 및 실내/외에 따른 VOCs(Benzene, Toluene, Xylene) 농도 및 상관성에 관한 연구 (A Study on the Correlation and Concentration in Volatile Organic Compounds(Benzene, Toluene, Xylene) Levels According to the Indoor/Outdoor and the Type of Residents' House in Industrial Area)

  • 이치원;전혜리;홍은주;유승도;김대선;손부순
    • 한국환경보건학회지
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    • 제36권5호
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    • pp.351-359
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    • 2010
  • The objectives of this study were to understand the characteristics of residents in industrial areas and factors affecting exposure to the Volatile Organic Compounds(VOCs : Benzene, Toluene, Xylene) as well as to assess exposure levels according to house-type, and whether residents were indoors or outdoors. This research was designed to assess the differences in exposure levels to indoor, outdoor and personal VOCs in a case group and a control group across all areas, as well as in each different area, from May to October 2007, in. 110 residents of the G, Y and H industrial areas of the Jun-nam province. The geometric mea-levels of airborne benzene for the case group 1.31part per billion(ppb) indoor, 1.29 ppb outdoor, and 1.32 ppb for personal exposure were significantly higher than for the control group 0.99, 0.87 and 0.57 ppb, respectively. The geometric mean level for toluene personal exposure across the G, Y and H areas was 5.70 ppb for the case group and 6.31 ppb for the control group. While the outdoor level was 4.27 ppb for the case group and 5.06 ppb for the control group, The indoor level for the case group was 4.78 ppb, similar to that of the control group 4.69 ppb. The geometric mean levels for airborne xylene across the G, Y and H areas were 0.16 ppb(outdoor), 0.12 ppb(personal exposure) and 0.10 ppb(indoor) for the case group, and for the control group were 0.17(personal exposure) and 0.09 ppb(indoor and outdoor). The indoor/outdoor(I/O) ratio for case group is 1.19, while that of the control group is 1.15, indicating that the indoor level was higher than the outdoor level. The interrelationship differences among the three different types of levels in the air in the G, Y and H areas are statistically significant, except for the difference between the indoor and outdoor figures for xylene. In terms of the different types of houses and energy type uesd, the geometric mean level for airborne benzene, toluene and xylene for houses were 1.61, 5.39 and 0.12 ppb, respectively. while the figures for flats were 0.67, 3.32 and 0.05 ppb, respectively. Outdoors, the levels of benzene and toluene in flats were 0.71 and 2.62 ppb, respectively. and 1.58 and 5.35 ppb in houses. For personal exposure, the house levels of benzene, toluene and xylene were all higher than for flats. Houses using oil for heating have significantly higher levels than flats, which use gas for heating.