• 한국대기환경학회지
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• 제23권4호
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• pp.430-439
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• 2007

The objective of this work is the air quality modeling according to the practical roughness length using the building information as surface boundary conditions. As accurate wind and temperature field are required to produce realistic urban air quality modeling, comparative simulations by various roughness length are discussed. The prognostic meteorological fields and air quality field over complex areas of Seoul, Korea are generated by the PSU/NCAR mesoscale model (MM5) and the Third Generation Community Multi-scale Air Quality Modeling System (Models-3/CMAQ), respectively. The simulated $O_3$ concentration on complex terrain and their interactions with the weak synoptic flow had relatively strong effects by the roughness length. A comparison of the three meteorological fields of respective roughness length reveals substantial localized differences in surface temperature and wind folds. Under these conditions, the ascended mixing height and weakened wind speed at night which induced the stable boundary stronger, and the difference of simulated $O_3$ concentration is $2{\sim}6\;ppb$.

• 응용통계연구
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• 제35권1호
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• pp.35-47
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• 2022

Receiver operating characteristic (ROC) 곡선은 이항 반응 자료에 대한 마커의 분류 예측력을 측정하기 위해 널리 적용되어왔으며 최근에는 생존 분석에서도 매우 중요한 역할을 하고 있다. 여러 가지 유형의 중도 절단과 원인 불명 등 다양한 종류의 결측 자료를 포함한 생존 자료 분석에서 마커의 사건 발생 여부에 대한 예측력을 판단하기 위해 기존의 통계량을 확장하였다. 생존 분석 자료는 각 시점에서의 사건 발생 여부로 이해할 수 있으며, 따라서 시점마다 ROC 곡선과 AUC를 구할 수 있다. 본 논문에서는 우중도 절단과 경쟁 위험 모형하에서 사용되는 다양한 방법론과 관련 R 패키지를 소개하고 각 방법의 특성을 설명하고 비교하였으며 이를 검토하기 위해 간단한 모의실험을 시행하였다. 또한, 프랑스에서 수집된 치매 자료의 마커 분석을 시행하였다.

• Tuberculosis and Respiratory Diseases
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• 제56권2호
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• pp.169-177
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• 2004

연구배경 : Cyclooxygenase는 비스테로이드성 항염증제의 주요 작용부위로 실험적 모델이나 역학적 연구에서 암 발생을 억제하는 것으로 알려져 있다. COX-2는 prostaglandin E2와 같은 prostaglandin 합성을 통해 종양의 성장, 침윤 그리고 신생혈관에 중요한 역할을 하는 것으로 알려져 있다. 본 연구에서는 절제된 비소세포폐암조직에서 COX-2의 발현과 COX-2의 예후인자로서의 의의를 조사해 보았다. 대상 및 방법 : 1997년부터 2002년까지 본원에 내원하여 원발성 비소세포폐암으로 진단 받은 후 근치 목적의 절제술을 받았던 환자 84명을 대상으로 파라핀 포매된 조직을 택하여 면역 화학염색 방법을 통하여 COX-2 의 발현을 관찰하였다. COX-2가 발현된 암세포의 비율이 10% 이상인 경우를 양성으로 하였다. 결 과 : 평균 연령은 63세, 남녀 비는 67:17이었으며, 조직병리학적 분류는 편평상피암 53례, 선암 24례, 대세포암 7례였다. 병기는 I 병기 37례, II 병기 29례, IIIA 병기 18례였다. 총 84례 중 COX-2는 양성군이 73%(61/84례), 음성군이 27%(23/84례)이었다. COX-2 발현과 TNM 병기, 조직학적 분류와는 유의한 상관관계가 없었으나, 중간 생존기간은 COX-2 양성군이 음성군보다 통계적으로 유의하게 짧았다. 결 론 : 비소세포폐암에서 COX-2 항원 발현 음성군이 중간 생존기간이 길었다.

• Journal of Hospice and Palliative Care
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• 제19권4호
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• pp.303-309
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• 2016

목적: 말기 암환자에서 악성 복수는 흔하게 발생하며, 그 자체가 나쁜 예후를 시사한다. 악성 복수에 대한 효과적이고, 최소한의 침습적인 방법으로 복수배액관 삽입이 제안되었다. 본 연구는 복수배액관 삽입을 시행한 말기 암환자들을 대상으로 복수배액관 시술의 효과와 부작용에 대하여 분석하고 시술 후 예후에 영향을 미치는 요인을 알아보기 위하여 시행되었다. 방법: 서울 소재 일개 3차 의료기관 호스피스 병동에 2010년 1월 1일부터 2013년 12월 31일까지 입원한 말기 암환자 2,608명 중 복수배액관 삽입을 시행한 67명의 환자들의 의무기록을 조사하였다. 인구학적 정보, 완화의료 수행지수, 혈액검사, 복수 배액관 유지 기간, 시술 합병증의 종류와 빈도, 항생제 사용 여부와 기간, 시술 후 생존기간을 분석하였다. 복수 배액관 삽입 후 생존기간에 영향을 미치는 요인을 평가하기 위해 단변량 및 다변량 콕스 비례위험 회귀분석을 실시하였다. 결과: 총 67명의 연구대상자 중 원발암은 간암 및 담도암과 위암이 가장 흔하였다. 복수배액관 시술 후 복수관련 증상의 호전은 55명(82.1%)에서 있었다. 시술 후 합병증은 통증(19.4%), 누수(14.9%), 배액관 빠짐(7.5%), 배액관 막힘(6%), 발열(4.5%)이었다. 복수배액관 시술 후 생존기간에 영향을 주는 인자는 다변량 콕스 비례위험 회귀분석 결과 완화의료 수행지수(HR 0.73; P=0.045), 저나트륨혈증(HR 2.77; P=0.003)이었다. 결론: 복수를 동반한 말기 암환자에서 복수 배액관 시술 시, 완화의료 수행지수와 저나트륨혈증은 예후 인자로 사용될 수 있을 것이다. 추후 대규모의 전향적 연구가 요구된다.

• 한국해안해양공학회지
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• 제16권4
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• pp.241-257
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• 2004

전구해양순환모형인 Bryan-Cox-Semtner모형에서 파생된 NCAR의 NCOM모형을 이용하여 한반도 주변해역의 해수순환을 가능한 세밀하게 해상시킨 예단적 전구해양순환모형을 수립하였다. 모형영역은 남북방향으로 $80.6{^\circ}S~88.6{^\circ}N$의 범위로서 북극해가 제외되었으며, 한반도 주변이 약 $0.3^\circ$로 해상된 수평 가변격자와 연직방향으로 15층으로 구성하였다. 섬 주변해안의 순환을 적절히 재현하기 위한 구멍완화법(Hole-relaxation method)을 적용하여 22개의 섬처리가 고려되었으며, NCAR에서 CSM(Climate System Model)운용을 위해 300년동안 spin-up 계산된 결과를 초기자료로 하고, Choi et al.(2002)의 접합 대기해양모형의 결과로부터 얻은 바람응력자료가 사용되었다. 모형결과로부터, 전구와 북서태평양 해역의 순환패턴을 살펴보았으며, 한반도 주변의 5개해협에서의 용적수송량을 Choi et al.(2002)의 결과 및 관측치와 비교하였다.

• 한국환경과학회지
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• 제16권8호
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• pp.921-928
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• 2007

The objective of this work is the air quality modeling according to the scenarios of emission on complex terrain. The prognostic meteorological fields and air quality field over complex areas of Seoul, Korea are generated by the PSU/NCAR mesoscale model (MM5) and the Third Generation Community Multi-scale Air Quality Modeling System (Models - 3/CMAQ), respectively. The emission source was driven from the Clean Air Policy Support System of the Korea National institute of Environmental Research (CAPSS), which is a 1 km x 1 km grid in South Korea during 2003. In comparison of air quality fields, the simulated averaged $PM_{10},\;NO_2,\;and\;O_3$ concentration on complex terrain in control case were decreased as compared with base case. Particularly $PM_{10}$ revealed most substantial localized differences by $(18{\sim}24{\mu}g/m^3)$. The reduction rate of $PM_{10},\;NO_2,\;and\;O_3$ is respectively 18.88, 13.34 and 4.17%.

• Asian Pacific Journal of Cancer Prevention
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• 제13권6호
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• pp.2639-2642
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• 2012

Background: The patterns of gastric cancer recurrence vary across societies. We designed the current study in an attempt to evaluate and reveal the outbreak of the recurrence patterns of gastric cancer and also prediction of time to recurrence and its effected factors in Iran. Materials and Methods: This research was performed from March 2003 to February 2007. Demographic characteristics, clinical and pathological diagnosis and classification including pathologic stage, tumor grade, tumor site and tumor size in of patients with GC recurrent were collected from patients' data files. To evaluate of factors affected on the relapse of the GC patients, gender, age at diagnosis, treatment type and Hgb were included in the research. Data were analyzed using Kaplan-Meier and logistic regression models. Results: After treatment, 82 patients suffered recurrence, 42, 33 and 17 by the ends of first, second and third years. The mean ( SD) and median ( IQR) time to recurrence in patients with GC were 25.5 (20.6-30.1) and 21.5 (15.6-27.1) months, respectively. The results of multivariate analysis logistic regression showed that only pathologic stage, tumor grade and tumor site significantly affected the recurrence. Conclusions: We found that pathologic stage, tumor grade and tumor site significantly affect on the recurrence of GC which has a high positive prognostic value and might be functional for better follow-up and selecting the patients at risk. We also showed time to recurrence to be an important factor for follow-up of patients.

• Asian Pacific Journal of Cancer Prevention
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• 제15권16호
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• pp.6559-6564
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• 2014

Objective: To evaluate the efficacy and safety of bevacizumab in the treatment of patients with metastatic colorectal cancer (mCRC). Methods: In a single-center, observational study of 91 Chinese patients with mCRC who received bevacizumab in combination with chemotherapy was conducted. Objective response rates (ORRs), progression-free survival (PFS), overall survival (OS) and adverse events were recorded, and the relationships between various clinical factors and PFS or OS were evaluated by Cox proportional hazards models. Results: Treatment with bevacizumab and chemotherapy was effective and tolerable. Univariate analysis showed that PFS and OS were significantly associated with the Eastern Cooperative Oncology Group performance status (ECOG-PS) score, duration of bevacizumab exposure, and whether chemotherapy was continued after discontinuation of bevacizumab treatment. A multivariate analysis showed that the duration of bevacizumab exposure and whether chemotherapy was continued after discontinuation of bevacizumab were independent prognostic factors for PFS and OS. Conclusion: In Chinese mCRC population, the shorter the duration of exposure to bevacizumab and chemotherapy, the worse the prognosis is.

• Journal of Preventive Medicine and Public Health
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• 제43권4호
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• pp.330-340
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• 2010

Objectives: This study aims to evaluate and explain the socioeconomic inequalities of all-cause mortality after breast cancer surgery in South Korea. Methods: This population based study included all 8868 females who underwent radical mastectomy for breast cancer between January 2002 and June 2003. Follow-up for mortality continued from January 2002 to June 2006. The patients were divided into 4 socioeconomic classes according to their socioeconomic status as defined by the National Health Insurance contribution rate. The relationship between socioeconomic status and all-cause mortality after breast cancer surgery was assessed using the Cox proportional hazards model with adjusting for age, the Charlson’s index score, emergency hospitalization, the type of hospital and the hospital ownership. Results: Those in the lowest socioeconomic status group had a significantly higher hazard ratio of 2.09 (95% CI =1.50 - 2.91) compared with those in the highest socioeconomic group after controlling for all the identifiable confounding variables. For allcause mortality after radical mastectomy, all the other income groups showed significantly higher 3-year mortality rates than did the highest income group. Conclusions: The socioeconomic status of breast cancer patients should be considered as an independent prognostic factor that affects all-cause mortality after radical mastectomy, and this is possibly due to a delayed diagnosis, limited access or minimal treatment leading to higher mortality. This study may provide tangible support to intensify surveillance and treatment for breast cancer among low socioeconomic class women.

• Asian Pacific Journal of Cancer Prevention
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• 제16권12호
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• pp.5081-5084
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• 2015

Background: Breast cancer is a malignant tumor that starts from cells of the breast and is seen mainly in women. It's the most common cancer in women worldwide and is a major threat to health. The purpose of this study was to fit a Cox proportional hazards model for prediction and determination of years of survival in Iranian patients. Materials and Methods: A total of 366 patients with breast cancer in the Cancer Research Center were included in the study. A Cox proportional hazard model was used with variables such as tumor grade, number of removed positive lymph nodes, human epidermal growth factor receptor 2 (HER2) expression and several other variables. Kaplan-Meier curves were plotted and multi-years of survival were evaluated. Results: The mean age of patients was 48.1 years. Consumption of fatty foods (p=0.033), recurrence (p<0.001), tumor grade (p=0.046) and age (p=0.017) were significant variables. The overall 1- year, 3-year and 5-year survival rates were found to be 93%, 75% and 52%. Conclusions: Use of covariates and the Cox proportional hazard model are effective in predicting the survival of individuals and this model distinguished 4 effective factors in the survival of patients.