• Journal of Hospice and Palliative Care
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• 제20권4호
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• pp.235-241
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• 2017

목적: Palliative Performance Scale (PPS)는 진행성 암환자에서 널리 사용되는 예후도구이다. PPS 측정이 생존에 대한 예측을 의미하지만, 연속적인 PPS 측정에 대한 유용성은 추가적인 연구가 필요하다. 본 연구에서는 완화 병동에 입원한 진행성 암환자를 대상으로 PPS score의 변화와 생존간의 연관성에 대해 진행한 연구이다. 방법: 2010년 1월부터 2012년 12월까지 서울성모병원 완화의학과에 입원한 환자 606에 대한 의무기록을 통하여 입원 당일의 PPS score와 입원 3일째의 PPS score 그리고, 두 score의 차이를 측정하여 점수의 변화와 생존간의 관련성을 분석하였다. 결과: PPS score의 변화와 생존과는 통계적으로 유의한 관련이 있었다. PPS score의 변화가 30% 이하인 군과 비교하였을 때, 30% 초과된 군에서 hazard ratio가 2.66(95% CI 2.19~3.22)로 확인되었다. 입원 3일째 PPS score가 30% 이하인 경우 독립적으로 생존에 대한 예측이 가능하였으며, PPS score 30% 초과된 군과 비교했을 때 hazard ratio는 1.67 (95% CI 1.38~2.02)로 확인되었다. 입원 당시의 PPS score는 생존과 독립적인 관련성은 없었다. 결론: 후향적으로 의무기록 분석을 통해 이루어진 본 연구에서 30% 이상의 PPS score 변화는 입원중인 말기 암환자의 생존과의 관련이 확인되었다. 입원 당시의 PPS score는 생존을 예측하지 못했다. PPS score의 변화는 말기암환자에서 단일 PPS score 측정보다 더 민감한 지표일 수 있다. 차후 더 많은 환자들에서 이에 대한 다기관, 전향적 연구가 필요하다.

• International Journal of Heart Failure
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• 제6권3호
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• pp.119-126
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• 2024

Background and Objectives: Beta-blockers (BBs) improve prognosis in heart failure (HF), which is mediated by lowering heart rate (HR). However, HR has no prognostic implication in atrial fibrillation (AF) and also BBs have not been shown to improve prognosis in heart failure with preserved ejection fraction (HFpEF) with AF. This study assessed the prognostic implication of BB in HFpEF with AF according to discharge HR. Methods: From the Korean Acute Heart Failure Registry, 687 patients with HFpEF and AF were selected. Study subjects were divided into 4 groups based on 75 beats per minute (bpm) of HR at discharge and whether or not they were treated with BB at discharge. Results: Of the 687 patients with HFpEF and AF, 128 (36.1%) were in low HR group and 121 (36.4%) were in high HR group among those treated with BB at discharge. In high HR group, HR at discharge was significantly faster in BB non-users (85.5±9.1 bpm vs. 89.2±12.5 bpm, p=0.005). In the Cox model, BB did not improve 60-day rehospitalization (hazard ratio, 0.93;95% confidence interval [95% CI], 0.35-2.47) or mortality (hazard ratio, 0.77; 95% CI, 0.22-2.74) in low HR group. However, in high HR group, BB treatment at discharge was associated with 82% reduced 60-day HF rehospitalization (hazard ratio, 0.18; 95% CI, 0.04-0.81), but not with mortality (hazard ratio, 0.77; 95% CI, 0.20-2.98). Conclusions: In HFpEF with AF, in patients with HR over 75 bpm at discharge, BB treatment at discharge was associated with a reduced 60-day rehospitalization rate.

• 한국안광학회지
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• 제19권2호
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• pp.135-143
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• 2014

목적: 국제표준에서 규정한 청색광위험함수를 도입하여 청색광차단렌즈에 대한 청색광차단율과 시감투과율을 평가한다. 방법: 8개사 총41종의 청색광차단렌즈에 대한 청색광차단율과 시감투과율을 구하기 위해 UV-VIS 분광광도계로 380~780 nm 범위에서의 분광투과율을 측정하였다. 청색광차단율은 ANSI Z80.3:2010 및 ISO 13666(한국표준 KS B ISO 13666:2004)에서 규정된 청색광위험함수를 도입하여 산출하였다. 결과: 전체 렌즈에 대한 청색광차단율 범위는 9.3%~96.8%, 투과율 범위는 53.5%~92.7%, 시감투과율 범위는 58.0%~98.1%이었다. 전반적으로 코팅 청색광차단렌즈는 시감투과율이 높은 경향이 있었고, 착색 청색광차단렌즈는 청색광차단율이 높은 경향이 있었다. 결론: 렌즈분광분포곡선의 분석으로부터 청색광차단렌즈의 성능을 향상시킬 수 있는 가능성이 있음을 확인할 수 있었다. 제조업체는 국제표준의 규정에 맞춰 성능을 평가할 수 있는 자체기술을 확보할 필요가 있다.

• Communications for Statistical Applications and Methods
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• 제18권4호
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• pp.485-493
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• 2011

The proportional likelihood ratio order is an extension of the likelihood ratio order for the non-negative absolutely continuous random variables. In addition, the Lindley distribution has been over looked as a mixture of two exponential distributions due to the popularity of the exponential distribution. In this paper, we first recalled the above concepts and then obtained various properties of the Lindley distribution due to the proportional likelihood ratio order. These results are more general than the likelihood ratio ordering aspects related to this distribution. Finally, we discussed the proportional likelihood ratio ordering in view of the weighted version of the Lindley distribution.

• 한국방재학회 논문집
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• 제11권3호
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• pp.17-28
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• 2011

본 연구에서는 초단기 예측강우의 편의(bias) 보정을 목적으로 G/R 비의 실시간 예측에 칼만 필터를 적용하였다. 초단기 예측강우로는 MAPLE 예측강우를 사용하였고, 강우의 임계치와 누적시간에 따른 G/R 비의 특성변화를 검토하여 G/R 비 산정방법도 개선하였다. 이러한 분석을 내륙, 산악, 해안 지역에 각기 적용하여 지역적 차이가 비교될 수 있도록 하였다. 결과적으로 강우의 임계치와 누적시간의 고려를 통해 안정화된 G/R 비의 산정이 가능하였으며, 이를 이용함으로서 예측 G/R 비의 정확성이 보다 향상되었다. 예측 G/R 비로 보정된 초단기 예측강우의 정도는 지역별로 내륙지역이 가장 우수한 것으로 나타난 반면에 해안지역에서 제일 열악한 것으로 나타났다.

• 한국방재학회 논문집
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• 제8권2호
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• pp.129-138
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• 2008

차수성이 요구되는 제체나 댐체에 대하여 안정성을 판단하고자 할 경우 파이핑 현상발생 여부를 검토한다. 제체나 댐체는 층 다짐을 수행하면서 축조되므로 투수성은 수평방향 투수계수($k_x$)와 연직방향 투수계수($k_y$)가 서로 다른 이방성이 될 수 있다. 본 연구에서는 여러 가지 투수계수 비(k-ratio=$k_y/k_x$k)에 따른 침투해석을 수행하여 유출동수경사와 침투유속을 파악하고, 이론식에 의한 한계동수경사와 경험식에 의한 한계유속과 각각 비교.검토하여 파이핑에 미치는 영향을 검토하였다. 연구결과 투수계수 비는 한계동수경사 개념으로 파이핑 현상발생에 대한 안정성을 검토할 경우 매우 중요한 요소로 작용하나, 한계유속 개념에 대해서는 상대적으로 중요도가 매우 낮은 것으로 확인되었다.

• Journal of Gastric Cancer
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• 제21권1호
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• pp.84-92
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• 2021

Purpose: To date, no studies have been performed on staging based on the lymph node ratio (LNR) in elderly patients with gastric cancer who may require limited lymph node (LN) dissection due to morbidity and tissue fragility. We aimed to develop a new N staging system using the LNR in elderly patients with gastric cancer. Materials and Methods: The present study included patients aged over 75 years who underwent curative gastrectomy between January 1989 and December 2018. Clinicopathological data including the number of retrieved and metastatic LNs were collected and the LNR values were obtained (LNR = the number of metastatic LNs/the number of retrieved LNs). Eleven LNR groups with intervals of 0.1 were divided into four stages based on the inflection points at which the hazard ratio (HR) increased. Survival analysis was performed to evaluate the prognostic value of the LNR. Results: The four LNR stages included LNR0 (n=364), LNR1 (n=128), LNR2 (n=103), and LNR3 (n=10). In the multivariate analysis, both N staging and LNR staging exhibited significant prognostic values for predicting survival outcomes. However, the incremental change in the hazard ratio (HR) between consecutive stages was greater for the LNR staging than for the N staging (HRs: 1.607, 2.758, and 3.675 for N staging; 1.583, 3.514, and 10.261 for LNR staging). Conclusions: LNR staging is more useful than N staging in predicting the prognosis in elderly patients with gastric cancer and may be used as a complement or alternative to N staging.

• 한국간담췌외과학회지
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• 제26권2호
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• pp.168-177
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• 2022

Backgrounds/Aims: The goal of the present study was to evaluate the prognostic value of lymph node ratio (LNR) in distal cholangiocarcinoma (DCC) after curative intended surgery. Methods: Clinicopathological data of 162 DCC patients who underwent radical intended surgery between 2012 and 2020 were analyzed retrospectively. Prognostic factors related to overall survival (OS) and disease-free survival (DFS) were evaluated. Results: Median OS time and DFS time were 41 and 29 months, and 5-year OS rate and DFS rate were 44.7% and 38.1%, respectively. In the univariate analysis, significant prognostic factors for OS were histologic differentiation, American Joint Committee on Cancer (AJCC) stage, positive lymph node count, LNR, R1 resection, and perineural invasion. Preoperative carcinoembryonic antigen, carbohydrate antigen 19-9, infiltrative type, histologic differentiation, AJCC stage, positive lymph node count, LNR, R1 resection, perineural invasion, and lymph-vascular invasion were significant prognostic factors for DFS in the univariate analysis. In the multivariate analysis, histologic differentiation, R1 resection, and LNR were the independent prognostic factors for both OS and DFS. The LNR ≥ 0.2 group had a significantly poor prognosis in terms of OS (hazard ratio, 3.915; p = 0.002) and DFS (hazard ratio, 5.840; p < 0.001). Conclusions: LNR has significant value as a prognostic factor of DCC related to OS and DFS. LNR has the potential to be used as a modified staging system with furthermore studies.

• 한국산업보건학회지
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• 제29권1호
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• pp.13-20
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• 2019

Objective: This study was performed to propose a domestic occupational exposure limit(OEL) following a health hazard assessment, calculation of a non-carcinogenicity reference concentration worker($RfC_{worker}$) value, and examination of international agencies' exposure limits. It also recommends legal management within the Occupational Safety and Health Act for PHMG-Phosphate(CAS No. 89697-78-9), It is a humidifier disinfectant that generated many lung injuries. Methods: We have investigated the recommendation or guidelines of foreign OEL for PHMG-Phosphate and the actual state of legal management in Korea. To examine the procedures and methods for recommendation OEL. Toxicological hazard and health hazard classifications were examined and a non-carcinogenicity $RfC_{worker}$ value was calculated for PHMG-Phosphate. An OEL and the necessity of legal management were recommended as well. Results and Conclusions: The OEL for PHMG-Phosphate is recommended to be $0.01mg/m^3$. The recommended OEL is close to 10 times the RfCworker value of $0.000833mg/m^3$ calculated from the chemical dose-response hazard assessment, which is a 2017 study. The CMIT/MIT(3:1) mixture, which was a social issue as a humidifier disinfectant substance, was also exposed to the same ratio in March 2018, establish the OEL. It is recommended to establish OEL for PHMG-Phosphate to prevent worker health hazards and for chemical safety management.

• Journal of the Korean Data and Information Science Society
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• 제17권4호
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• pp.1067-1076
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• 2006

Although the proportional hazards model is the most common approach used for studying the relationship of event times and covariates, alternative models are needed for occasions when it does not fit data. In the two-sample case, proportional odds models are useful for fitting data whose hazard rates converge asymptotically. In this thesis, we propose a new estimator of the relative odds ratio of the proportional odds model when two independent random samples are observed under uncensorship. We prove the asymptotic normality and consistency of the estimator by using martingale-representation. The efficiency of the proposed is assessed through a simulation study.