• 제목/요약/키워드: Case-crossover study

검색결과 44건 처리시간 0.025초

1996년 이후 패션 콜렉션에 나타난 크로스오버 코디네이션에 관한 연구 (A Case Study on Crossover Coordination Applied in Fashion Collection since 1996)

  • 김칠순;유희정
    • 복식문화연구
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    • 제14권3호
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    • pp.457-468
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    • 2006
  • The purpose of this study was to understand fashion trend and characteristics by finding out the influences of crossover on modern fashion coordination through the identification of crossover coordination trend and characteristics. With a review of the literature, this study analyzed crossover coordination according to the types of expression methodology, periodical changes and designer's tastes that appeared through the collections of the six representative designers from 1996 to 2004. The results of this study were as follows. As a result of analysis of our sources, we realized that crossover coordination was shown most frequently in 1997 and Christian Dior was the designer who used crossover coordination most frequently. Among lots of crossover coordination cases, most of the cases are the coordination with different materials. In our results, trends of crossover coordination in materials appeared again about every five years cycle. Christian Dior combined different elements through silhouette and material, Dolce & Gabbana combined images and Jean Paul Gaultier combined different elements in the aspect of purpose and wearing configuration.

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기아자동차 SOUL의 혁신적인 제품전략 - 소비자의 soul을 움직이다 - (Innovative Product Strategy of KIA SOUL - Attract customers' soul -)

  • 이두희;이종호;전기흥
    • Asia Marketing Journal
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    • 제11권3호
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    • pp.151-165
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    • 2009
  • 본 사례는 Crossover Utility Vehicle (CUV)의 선구자인 기아자동차 SOUL이 혁신적인 제품전략을 통하여 어떻게 새로운 시장을 개척하였는지를 분석하고 있다. 지금까지 대부분의 자동차 제조업체들은 전통적인 시장세분화 기준에 치중하여, 여러 소비자 계층들을 동시에 만족시킬 수 있는 신제품 개발의 기회를 놓치고 있었다. 기아자동차 SOUL은 여러 소비자 계층을 만족시킬 수 있는 제품에 대한 기회를 포착하고, 기존 소비자 계층별 가치를 통합적으로 제공하여 새로운 시장을 열었다. 본 사례는 포화상태에 있는 자동차 산업에서 혁신적인 제품전략을 통해 신시장을 개척하는 과정을 잘 보여주고 있다. 기아자동차 SOUL의 혁신적 제품전략을 크게 디자인 혁신, CUV 시장 개척, 고객을 위한 맞춤서비스 제공, 그리고 기능 혁신의 4가지 축으로 설명하고 있다. 기아자동차 SOUL의 혁신적인 제품전략은 블루오션 개척을 계획하고 있는 많은 기업에게 의미 있는 시사점을 제공해 준다.

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$PM_{10}$ Exposure and Non-accidental Mortality in Asian Populations: A Meta-analysis of Time-series and Case-crossover Studies

  • Park, Hye Yin;Bae, Sanghyuk;Hong, Yun-Chul
    • Journal of Preventive Medicine and Public Health
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    • 제46권1호
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    • pp.10-18
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    • 2013
  • Objectives: We investigated the association between particulate matter less than $10{\mu}m$ in aerodynamic diameter ($PM_{10}$) exposure and non-accidental mortality in Asian populations by meta-analysis, using both time-series and case-crossover analysis. Methods: Among the 819 published studies searched from PubMed and EMBASE using key words related to $PM_{10}$ exposure and non-accidental mortality in Asian countries, 8 time-series and 4 case-crossover studies were selected for meta-analysis after exclusion by selection criteria. We obtained the relative risk (RR) and 95% confidence intervals (CI) of non-accidental mortality per $10{\mu}g/m^3$ increase of daily $PM_{10}$ from each study. We used Q statistics to test the heterogeneity of the results among the different studies and evaluated for publication bias using Begg funnel plot and Egger test. Results: Testing for heterogeneity showed significance (p<0.001); thus, we applied a random-effects model. RR (95% CI) per $10{\mu}g/m^3$ increase of daily $PM_{10}$ for both the time-series and case-crossover studies combined, time-series studies relative risk only, and case-crossover studies only, were 1.0047 (1.0033 to 1.0062), 1.0057 (1.0029 to 1.0086), and 1.0027 (1.0010 to 1.0043), respectively. The non-significant Egger test suggested that this analysis was not likely to have a publication bias. Conclusions: We found a significant positive association between $PM_{10}$ exposure and non-accidental mortality among Asian populations. Continued investigations are encouraged to contribute to the health impact assessment and public health management of air pollution in Asian countries.

대기중 총분진과 사망자수에 관한 분석 (An analysis of air apollution and daily mortality)

  • 김호
    • 응용통계연구
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    • 제13권2호
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    • pp.265-274
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    • 2000
  • 대기오염 자료와 사망자수 자료를 이용하여 대기중 총분진이 사망자수에 미치는 영향을 1996~1997년 서울 자료를 이용하여 분석하였다. 대기오염 자료에서 보이는 강한 계절성과 장기간의 경향 그리고 기온과 습도의 비선형관계를 고려하여 일반화 부가모형(generalized additive model)을 사용하였고, 그 결과 대기중 총분진 100$\mu$g/㎥ 증가시 초과사망자는 3%(95% 신뢰구간 : 0.8-5.2)로 추정되었다. 사례-교차연구(case-crossover study)의 결과를 보면 한 방향(후향적, 전향적)으로의 대조기간 설정 방법은 편향된 추정치를 주었고 양방향 방법은 회귀계수의 추정치는 일반화 부가모형과 거의 같은 결과를 주었지만 표준오차는 상대적으로 큰 값을 주었다. 이상에서 볼 때 대기오염 자료의 분석과 같이 계절성이 큰 자료에서는 사례-교차 연구를 적용할 때 주의가 요구됨을 알 수 있었다.

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도로선형최적화를 위한 유전자 연산자의 적용 (Incorporating Genetic Operators into Optimizing Highway Alignments)

  • 김응철
    • 대한교통학회지
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    • 제22권2호
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    • pp.43-54
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    • 2004
  • 본 연구에서는 인공지능(Artificial Intelligence)방법 중의 하나인 유전자 알고리즘(Genetic Algorithm)을 도로선형최적화 모형개발의 탐색엔진으로 활용하기 위한 핵심도구인 유전자 연산자(Genetic Operator)의 개발과 적용과정을 통해 그 특징과 유용성을 제시하였다. 균일돌연변이 연산자, 직선돌연변이 연산자. 비균일 돌연변이 연산자, 전체 비균일 돌연변이 연산자 등 4개의 돌연변이 연산자가 탐색영역(Search space)의 가능한 모든 부분을 탐험(Exploration)하기 위해 적용되었으며, 단순교차 연산자, 두 개의 점을 이용한 교차 연산자, 산술교차 연산자, 학습교차 연산자 등 4개의 교차 연산자가 노선대안의 우수한 유전형질을 다음세대에 효과적으로 전달(Exploitation)하기 위해 시험되었다. 사례연구와 민감도 분석과정을 통해 유전자 알고리즘 및 개발 적용된 8개 유전자 연산자의 도로선형최적화과정 도입이 우수한 노선대안을 빠르고 효과적으로 탐색함을 알 수 있었으며, 돌연변이 연산자와 교차 연산자의 효과적 조합이 상호보완기능을 통해 탐색능력의 향상에 큰 영향을 끼치는 것으로 파악되었다. 또한, 개발 적용된 연산자 이외에도 새로운 연산자의 개발 가능성이 무한하며, 이는 도로선형최적화에 유전자 알고리즘의 적용이 타당함을 반증함도 주목할 만하다.

환자교차 설계 방법을 적용한 소아천식 입원에 대한 도시 대기오염의 급성영향평가 (Associations between Air Pollution and Asthma-related Hospital Admissions in Children in Seoul, Korea: A Case-crossover Study)

  • 이종태
    • Journal of Preventive Medicine and Public Health
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    • 제36권1호
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    • pp.47-53
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    • 2003
  • Objectives : I used a case-crossover design to investigate the association between air pollution, and hospital admissions for asthmatic children under the age of 15 years in Seoul, Korea Methods : I estimated the changes in the levels of hospitalization risk from theinterquartile (IQR) increase in each pollutant concentrations, using conditional logistic regression analyses, with controls for weather information. Results : Using bidirectional control sampling, the results from a conditional logistic regression model, with controls for weather conditions, showed the estimated relative risk of hospitalization for asthma among children to be 1.04 (95% confidence interval (CI), 1.01-1.08) for particulate matter with an aerodynamic diameter less than or equal to 10m (IQR=40.4ug/m3); 1.05 (95% CI, 1.00- 1.09) for nitrogen dioxide (IQR=14.6ppb): 1.02 (95% CI,0.97-1.06) for sulfur dioxide (IQR=4.4ppb): 1.03 (95% CI, 0.99-1.08) for ozone (IQR=21.7ppb): and 1.03 (95% CI, 0.99-1.08) for carbon monoxide f10R=1.0ppm). Conclusions : This empirical analysis indicates the bidirectional control sampling methods, by design, would successfully control the confounding factors due to the long-term time trends of air pollution. These findings also support the hypothesis that air pollution at levels below the current ambient air quality standards of Korea is harmful to sensitive subjects, such as asthmatic children.

Application of Crossover Analysis-logistic Regression in the Assessment of Gene- environmental Interactions for Colorectal Cancer

  • Wu, Ya-Zhou;Yang, Huan;Zhang, Ling;Zhang, Yan-Qi;Liu, Ling;Yi, Dong;Cao, Jia
    • Asian Pacific Journal of Cancer Prevention
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    • 제13권5호
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    • pp.2031-2037
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    • 2012
  • Background: Analysis of gene-gene and gene-environment interactions for complex multifactorial human disease faces challenges regarding statistical methodology. One major difficulty is partly due to the limitations of parametric-statistical methods for detection of gene effects that are dependent solely or partially on interactions with other genes or environmental exposures. Based on our previous case-control study in Chongqing of China, we have found increased risk of colorectal cancer exists in individuals carrying a novel homozygous TT at locus rs1329149 and known homozygous AA at locus rs671. Methods: In this study, we proposed statistical method-crossover analysis in combination with logistic regression model, to further analyze our data and focus on assessing gene-environmental interactions for colorectal cancer. Results: The results of the crossover analysis showed that there are possible multiplicative interactions between loci rs671 and rs1329149 with alcohol consumption. Multifactorial logistic regression analysis also validated that loci rs671 and rs1329149 both exhibited a multiplicative interaction with alcohol consumption. Moreover, we also found additive interactions between any pair of two factors (among the four risk factors: gene loci rs671, rs1329149, age and alcohol consumption) through the crossover analysis, which was not evident on logistic regression. Conclusions: In conclusion, the method based on crossover analysis-logistic regression is successful in assessing additive and multiplicative gene-environment interactions, and in revealing synergistic effects of gene loci rs671 and rs1329149 with alcohol consumption in the pathogenesis and development of colorectal cancer.

환자-교차 대조군 연구를 적용한 산업재해 발생의 단기적 영향 요인 (Transient Effects the Risk of Occupational Injuries as an Acute Events : a Case-crossover Study)

  • 정선아;원종욱;노재훈;이종태
    • Journal of Preventive Medicine and Public Health
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    • 제34권1호
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    • pp.35-40
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    • 2001
  • Objectives : To elucidate the transient effects on the risk of occupational injuries as acute events and establish so alternative proposal. Methods : The study population comprised a total of 302 workers randomly selected from applications for occupational injury compensation reported to the Inchon local labor office from January 1. 1999 to December 31. A case-crossover design, where each case serves its own control, was applied to this study. Through a telephone interview, workers provided useful data concerning five job related stressful events such as company transfer, work load change, overtime work, exchange duty, and work-part transfer. They were asked whether there were stressful events within a week of the occurrence of injury and the degree of stress. Exposure status from one year prior was used as control information. In the end, the data provided by 158 of selected persons was used for the analysis based on the quality of the data provided by the participants. A conditional logistic regression was used to discover the transient effects on the risk of occupational injuries as acute events. Results : The effects a company transfer and work load change on occupational injury was statistically significant on the risk of occupational Injuries as an acute event(RR=5.5, 95% CI=2.501-12.428; RR=3.1, 95% CI=1.963-5.017, respectively). Other stressful events were found to elevate the risk factor for the occurrence of occupational jujury, but were not significant. Conclusions : Our results suggested that transient stressful events elevated the risk factor for the occurrence of occupational injury.

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Air pollution and hospital admissions for chronic obstructive pulmonary disease: are their potentially sensitive groups?

  • Tsai, Shang-Shyue;Yang, Ya-Hui;Liou, Saou-Hsing;Wu, Trong-Neng;Yang, Chun-Yuh
    • Advances in environmental research
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    • 제1권1호
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    • pp.57-68
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    • 2012
  • Recent studies showed that air pollution is a risk factor for hospitalization for chronic obstructive pulmonary disease (COPD). However, there is limited evidence to suggest which subpopulations are at higher risk from air pollution. This study was undertaken to examine the modifying effect of specific secondary diagnosis (including hypertension, diabetes, pneumonia, congestive heart failure) on the relationship between hospital admissions for COPD and ambient air pollutants concentrations. Hospital admissions for COPD and ambient air pollution data for Taipei were obtained for the period from 1999-2009. The relative risk of hospital admissions for COPD was estimated using a case-crossover approach. None of the secondary diagnosis we examined showed much evidence of effect modification.