• 제목/요약/키워드: Hazard-rate model

검색결과 248건 처리시간 0.026초

Who are the Breast Cancer Survivors in Malaysia?

  • Ibrahim, Nor Idawaty;Dahlui, M.;Aina, E.N.;Al-Sadat, N.
    • Asian Pacific Journal of Cancer Prevention
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    • 제13권5호
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    • pp.2213-2218
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    • 2012
  • Introduction: Worldwide, breast cancer is the commonest cause of cancer death in women. However, the survival rate varies across regions at averages of 73%and 57% in the developed and developing countries, respectively. Objective: This study aimed to determine the survival rate of breast cancer among the women of Malaysia and characteristics of the survivors. Method: A retrospective cohort study was conducted on secondary data obtained from the Breast Cancer Registry and medical records of breast cancer patients admitted to Hospital Kuala Lumpur from 2005 to 2009. Survival data were validated with National Birth and Death Registry. Statistical analysis applied logistic regression, the Cox proportional hazard model, the Kaplan-Meier method and log rank test. Results: A total of 868 women were diagnosed with breast cancer between January 2005 and December 2009, comprising 58%, 25% and 17% Malays, Chinese and Indians, respectively. The overall survival rate was 43.5% (CI 0.573-0.597), with Chinese, Indians and Malays having 5 year survival rates of 48.2% (CI 0.444-0.520), 47.2% (CI 0.432-0.512) and 39.7% (CI 0.373-0.421), respectively (p<0.05). The survival rate was lower as the stages increased, with the late stages were mostly seen among the Malays (46%), followed by Chinese (36%) and Indians (34%). Size of tumor>3.0cm; lymph node involvement, ERPR, and HER 2 status, delayed presentation and involvement of both breasts were among other factors that were associated with poor survival. Conclusions: The overall survival rate of Malaysian women with breast cancer was lower than the western figures with Malays having the lowest because they presented at late stage, after a long duration of symptoms, had larger tumor size, and had more lymph nodes affected. There is an urgent need to conduct studies on why there is delay in diagnosis and treatment of breast cancer women in Malaysia.

산업재해 발생에 영향을 미치는 건강요인에 관한 연구 (A Study on the Physical and Mental Health Factors affecting Industrial Accidents)

  • 이명선;노재훈;문영한
    • Journal of Preventive Medicine and Public Health
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    • 제22권3호
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    • pp.355-367
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    • 1989
  • This study examined the physical and mental health factors affecting the industrial accidents of 142 injured and 1,212 uninjured workers in the shipbuilding industry from 1986 to 1988. The results acquired from the Todai Health Index (THI) and from analysis of the health examination were as follows: 1. Among the personal characteristics of the workers, the educational level of injured workers was significantly lower than that of the uninjured workers. 2. Among the physical characteristics, vision and $R\ddot{o}hrer$ Index of the injured workers were lower than those of the uninjured workers, and the difference was statistically significant. On the other hand, the differences in height, weight, hearing function, hematocrit, blood pressure, urine test, and X-ray findings were not statistically significant between the injured and uninjured workers. 3. The score of the THI questionnaire on the physical and mental health of the injured workers was higher than that of the uninjured workers, and the difference was statistically significant. 4. Form the THI score, the industrial workers had complained more about mental health than physical health and there was a statistically singinficant relation with the industrial accidents. 5. The relative risk expressed in terms of the odds ratio was 2.9 for poorer vision, 2.7 for a lower educational level, 2.2 for a higher THI score and 1.6 for overdrinking. 6 Educational level, vision, and the THI score were selected as significant factors influencing industrial accidents based on a log-linear model. According to the results of this model by logistic analysis, the odds ratio of industrial accidents was 1.8 for a lower educational level, 1.7 for poorer vision, and 1.6 for a higher THI score. 7 By event history analysis with the dependent variable as the duration of work at the time of the industrial accident, educational level, age, $R\ddot{o}hrer$ Index and THI score were the statistically significant variables selected, and the hazard rate of industrial accident occurrence was 0.24 for a lower educational level, 0.92 for age, 0.99 for a lower $R\ddot{o}hrer$ Index and 2.72 for a higher THI score. As we have seen, educational level and THI score were the most significant factors affecting the hazard rate of industrial accidents. Vision, $R\ddot{o}hrer$ Index, age, and drinking behavior were also statistically significant variables influencing industrial accidents. Therefore, in order to prevent industrial accidents, it is necessary to establish a health management plan for industry which can objectively evaluate not only the physical but also the mental health of the workers. If we use this type of study as a prospective study design, we can determine the relative risk of physical and mental health factors on industrial accidents. Furthermore, it is expected that this type of study will provide workers at high risk with more precise basic data for a health managment plan for industrial accident prevention.

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어랑분포의 형상모수 변화에 따른 소프트웨어 개발 비용모형에 관한 비교 연구 (The Comparative Software Development Cost Model Considering the Change in the Shape Parameter of the Erlang Distribution)

  • 양태진
    • 한국정보전자통신기술학회논문지
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    • 제9권6호
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    • pp.566-572
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    • 2016
  • 소프트웨어 개발과정에서 소프트웨어 신뢰성은 매우 중요한 문제 중에 하나이다. 소프트웨어 고장현상을 분석하기 위하여 비동질적인 포아송과정에서 고장 발생 추이를 의미하는 위험함수가 고장시간에 독립적으로 일정하거나, 종속적인 경우, 즉 비-증가 또는, 비-감소하는 속성을 가질 수 있다. 본 연구에서는 소프트웨어 제품 테스팅 과정에서 고장 수명분포로서 어랑분포의 다양한 형상모수를 고려한 소프트웨어 개발 비용 분석에 대하여 연구되었다. 소프트웨어 고장현상을 분석하기 위하여 모수추정은 최우추정법이 사용되었다. 따라서 본 논문에서는 어랑분포의 형상모수를 고려한 소프트웨어 개발비용모형 분석을 위하여 소프트웨어 고장간격 시간자료를 이용하여 비교 및 평가하였다. 그 결과 형상모수에 따른 비용곡선을 비교 하였을 때 형상모형이 작을수록 비용이 많고 소프트웨어 최적 방출시간이 지연 됨을 알 수 있었다. 이 연구를 통하여 소프트웨어 개발자들에게 소프트웨어 형상모수에 따른 개발 비용을 탐색하는데, 기본적으로 도움을 줄 수 있는 사전정보의 역할을 할 수 있을 것으로 판단된다.

캐나다 산불 기상지수를 이용한 산불발생확률모형 개발 -강원도 지역 산불발생을 중심으로- (A Study on the Development of Forest Fire Occurrence Probability Model using Canadian Forest Fire Weather Index -Occurrence of Forest Fire in Kangwon Province-)

  • 박흥석;이시영;채희문;이우균
    • 한국방재학회 논문집
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    • 제9권3호
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    • pp.95-100
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    • 2009
  • 캐나다의 산불 위험등급 시스템의 구성요소인 미세연료수분지수는 지상의 미세 연료의 건조 여부의 예측을 통해 산불의 발화위험성을 지시하는 지수로써, 강수량의 감소와 온도의 상승, 풍속의 상승, 그리고 대기 중의 습도 감소로 인한 미세연료의 발화위험성의 상승을 표시하는 지수이다. 본 연구에서는 5년간의 강원도 지역에서의 기상 자료를 분석하고, 이를 이용하여 미세연료수분지수를 산출하여, 그 연중 분포와 적용성을 검토하였다. 분석 결과, 강원도 지역의 기후 조건은 봄철과 가을철 산불 조심강조기간에 아주 적은 강수량과 낮은 습도를 보여주고 있으며, 지난 5년간의 발생한 산불 중 75%가 산불 조심 강조기간에 발생하였으며, 그 중 90%가 봄철 산불조심기간에 집중되어 있었다. 또한, 봄철 산불조심 강조기간을 대상으로 순기 평균 산불연료지수에 대한 로지스틱 분석 결과 약 63%의 판별율을 나타내었다. 하지만, 모형의 정확도 향상을 위한 기상 자료의 보다 정확한 지역간 분류가 필요할 것으로 판단된다.

콕스 비례위험모형을 이용한 산불피해 소나무의 생존분석 (Survival Analysis of Forest Fire-Damaged Korean Red Pine (Pinus densiflora) using the Cox's Proportional Hazard Model)

  • 배정현;정유경;안수정;강원석;이영근
    • 한국산림과학회지
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    • 제113권2호
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    • pp.187-197
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    • 2024
  • 본 연구에서는 콕스 비례위험모형을 이용하여 산불피해 소나무의 고사에 영향을 미치는 인자를 밝히고자 하였다. 지표화 피해 소나무를 대상으로 고사 영향 인자를 조사하고 산불 발생 7년 차까지 고사 발생 모니터링을 수행하였다. 수집된 자료를 기반으로 생존분석을 실시하였다. 분석 결과, 고사 위험성을 증가시키는 변수는 dNDVI(delta Normalized Difference Vegetation Index), dNBR(delta Normalized Burn Ratio), 경사, 나무에 남겨진 그을음의 상대적인 면적과 평균적인 높이를 나타내는 수피 그을음 지수(Bark Scorch Index, BSI)와 수피 그을음 높이(Bark Scorch Height, BSH)로 나타난 반면, 음의 관계를 가지는 변수는 고도, 흉고직경, 수관층 수분스트레스 변화를 나타내는 수분스트레스지수(dleta Moisture Stress Index, dMSI)로 나타났다(p<0.001). 콕스 비례위험모형의 유의성을 확인하기 위한 변수별 비례위험가정검증에서는 사면방향을 제외한 모든 인자가 모형에 적합하며 고사 발생에 유의미한 영향을 미치는 것으로 나타났다. 생존 곡선 분석에서 가장 큰 생존율 차이를 보인 변수는 BSI였으며(p<0.0001), 원격탐사를 통해 얻어진 환경변화 인자들(dNDVI, dNBR, dMSI) 역시 큰 생존율 차이를 나타내었다(p<0.0001). 이러한 결과는 산불 이후 소나무의 잠재적인 고사위험성을 고려한 복원계획 수립을 위한 기초자료로 활용될 것으로 기대된다.

비신호 교차로에서 횡단 기다림 시간 및 시도횟수에 관한 보행행태 연구 (Analysis on Pedestrian Behavior Focused on Waiting Time and Trial Frequency for Crossing in the Unsignalized Intersection)

  • 장태연;오도형
    • 대한토목학회논문집
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    • 제35권2호
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    • pp.427-436
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    • 2015
  • 본 논문은 무신호 교차로에서 보행자의 횡단행태에 영향을 주는 요소를 분석하였다. 보행행태는 교차로 주변의 환경과 횡단의 기준, 안전에 대한 예견, 순간적인 판단 등이 복합적으로 작용하는 정신적 스트레스의 결과이다. 이러한 복합적 스트레스는 개인의 속성, 교통여건, 환경요인 등 다양한 요인에 의해 영향을 받는데, 이러한 영향요인을 파악하여 교차로를 운영하는데 있어 보행친화적인 환경을 조성할 필요가 있다. 현장과 설문 조사를 통하여 보행자가 비신호 교차로를 횡단하는데 있어서 영향을 주는 다양한 결정변수를 기초로 하여 횡단시도 횟수, 기다림 시간 및 보행횡단 만족도 등에 대한 횡단행태를 분석하는 것이 목적이다. 횡단시도횟수에 대한 각 요소별 특성을 분석하기 위해 $x^2$테스트를 실시하였으며 횡단을 위한 기다림 시간에 영향을 주는 요소를 분석하기 위해 위험률 모형을 구축하였다. 마지막으로 구조방정식을 적용하여 보행자의 보행 횡단 환경에 대한 만족도에 대한 직 간접 효과도 제시되었다.

Clinicopathological Significance of Elevated PIK3CA Expression in Gastric Cancer

  • Jang, Si-Hyong;Kim, Kyung-Ju;Oh, Mee-Hye;Lee, Ji-Hye;Lee, Hyun Ju;Cho, Hyun Deuk;Han, Sun Wook;Son, Myoung Won;Lee, Moon Soo
    • Journal of Gastric Cancer
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    • 제16권2호
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    • pp.85-92
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    • 2016
  • Purpose: PIK3CA is often mutated in a variety of malignancies, including colon, gastric, ovary, breast, and brain tumors. We investigated PIK3CA expression in gastric cancer and explored the relationships between the PIK3CA expression level and clinicopathological features as well as survival of the patients. Materials and Methods: We examined PIK3CA expression in a tissue microarray of 178 gastric adenocarcinomas by immunohistochemistry and reviewed patients' medical records. Results: In our study, 112 of the 178 gastric cancer patients displayed positive PIK3CA expression. Overexpression of PIK3CA was correlated with low grade differentiation (P=0.001), frequent lymphatic invasion (P=0.032), and high T stage (P=0.040). Patients with positive PIK3CA staining were more likely to display worse overall survival rate than those with negative PIK3CA staining, as determined by Kaplan-Meier survival analysis with log-rank test (P=0.047) and a univariate analysis using the Cox proportional hazard model (hazard ratio=1.832, P=0.051). Conclusions: Elevated PIK3CA expression was significantly correlated with tumor invasiveness, tumor phenotypes, and poor patient survival.

혈당강하제 단독요법 투여 당뇨병환자에서 암발생률 평가: 후향적 코호트 연구 (Cancer Risk in Patients with Type 2 Diabetes on Antidiabetic Monotherapy: A Population Based Cohort Study Using National Insurance Health Service Database)

  • 정한영;이숙향
    • 한국임상약학회지
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    • 제29권3호
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    • pp.186-192
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    • 2019
  • Background: Diabetes is associated with cancer risk in the aging population. Observational studies have indicated the beneficial effects of metformin against breast cancer, making studies on the anticancer potential of antidiabetic drugs worthwhile. This study investigated cancer incidence in patients on antidiabetic monotherapy. Methods: Using National Health Insurance Service data (2002-2013), a retrospective cohort study that included type 2 diabetes mellitus (T2DM) patients was conducted. Study subjects were enrolled if they were ${\geq}30$ years old, on monotherapy for diabetes, and cancer-free. They were followed up for cancer occurrence or death, until December 31st, 2013. A Cox proportional hazard model analysis was conducted between metformin and sulfonylurea (including meglitinide) users, to determine cancer risk, with adjustment for age, gender, comorbidity index, dyslipidemia, hypertension, and T2DM duration. Results: The number of antidiabetic monotherapy-treated T2DM patients without a history of cancer was 9,554 (metformin, n = 5,825; sulfonylurea, n = 3,225; others, n = 504). During the follow-up period (mean, 2.04; IQR, 3.18 years), the cancer incidence rate was 5.48/100 and 5.45/100 patient-years for metformin and sulfonylurea, respectively. The hazard ratio (HR) for risk of cancer incidence in the metformin group was 0.74 (95% confidence interval [CI], 0.66-0.83; p < 0.0001), compared with sulfonylurea. Additionally, the HRs for risks of lung, liver, and stomach cancer were respectively 0.46 (95% CI, 0.31-0.66; p < 0.0001), 0.41 (95% CI, 0.31-0.54; p < 0.0001), and 0.51 (95% CI, 0.35-0.73; p = 0.0003). Conclusion: Antidiabetic therapy with metformin reduces cancer risk by 26%, specifically for lung, liver, and stomach cancer.

고혈압 환자에서 한방의료기관 이용과 심혈관 위험 요소와의 관계: 국민건강보험공단 표본코호트 DB (Association between Korean Medicine Hospital Utilization and Cardiovascular Risks in Patients with Hypertension: a National Korean Cohort Study)

  • 조현주;정혜진;임사비나
    • 대한한의학회지
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    • 제40권3호
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    • pp.1-20
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    • 2019
  • Objectives: This study aims to investigate the effects of Korean Medicine Hospital Utilization (KMHU) on major adverse cardiovascular events (MACE), myocardial infarction (MI), stroke, and death in hypertensive patients taking antihypertensives. Methods: Using the Korean National Health Insurance Service-National Sample Cohort database, this study identified and diagnosed 68,457 hypertensive patients taking antihypertensives between 2003 and 2006. They were divided into KMHU and non-KMHU groups. The follow-up period ended with the diagnosis of myocardial infarction, stroke, or death. After propensity score matching (PSM), there were 18,242 patients each in the non-KMHU and KMHU groups. We calculated the incidence rate, hazard ratio (HR), and 95% confidence interval (CI) for MACE, myocardial infarction, stroke, and death in patients with hypertension using a stratified Cox proportional hazard model. In addition, secondary outcome analyses for stroke and cardiovascular mortality were performed. Results: After PSM, the HRs for MACE (HR: 0.84, 95% CI: 0.81-0.87), all-cause mortality (HR: 0.75, 95% CI: 0.72-0.79), and myocardial infarction (HR: 0.90, 95% CI: 0.83-0.97) were significantly lower in the KMHU group than in the non-KMHU group. Moreover, the HRs for stroke-related mortality, haemorrhage and ischaemic stroke-related mortality, and ischaemic heart disease-related and circulatory system disease-related mortality were significantly lower in the KMHU group than in the non-KMHU group. Conclusions: On long-term follow-up observation, this study supported the effect of KMHU for managing hypertension and reducing the burden of cardiovascular diseases.

Radon Exhalation from Five Wood Species

  • Lee, Ju Yong;Choi, Gyu Woong;Kang, Seog Goo
    • Journal of the Korean Wood Science and Technology
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    • 제46권6호
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    • pp.735-747
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    • 2018
  • Radon radiation exposures in home have been posed as a potential cancer hazard. This research aims to present the basic data of the indoor radon concentration level by examining the radon exhalation rates of wood species. Radon exhalation rates from five commonly used wood species in Korean wood building construction were measured with Continuous Radon Monitor (CRM), Model 1028 (Sun Nuclear Co., USA) using the Closed Chamber Method (CCM). The mass exhalation rate was observed to vary from $0.00089Bq{\cdot}kg^{-1}{\cdot}h^{-1}$ to $0.00181Bq{\cdot}kg^{-1}{\cdot}h^{-1}$, whereas the surface exhalation rate was observed to be $0.00677-0.01517Bq{\cdot}m^{-2}{\cdot}h^{-1}$. The radon exhalation rate of Quercus accutissima Carruth (white oak) which has the highest density showed the highest figure among the five wood species, on the other hand, the rest of four species showed similar results which were similar to the radon exhalation rates of wood in the U.S.A. and Canada. The average of the concentration measured by the CCM represented well up to the second half-life period (7.7 days). Because result of these small quantities seems to indicate that radon exhalation from the tested wood species has almost negligible impact, the main culprit of the high indoor radon concentration is clearly derived from the background of surrounding wood house. Therefore, as a safety precaution, infrastructures made of wood materials should be designed with the consideration of influx of radon and built accordingly. Furthermore, it is highly desirable that wood will be needed to use for furniture and interior finishing material in indoor environment.