• Journal of Chest Surgery
• /
• 제54권2호
• /
• pp.88-98
• /
• 2021

Background: This study aimed to develop a new risk prediction model for operative mortality in a Korean cohort undergoing heart valve surgery using the Korea Heart Valve Surgery Registry (KHVSR) database. Methods: We analyzed data from 4,742 patients registered in the KHVSR who underwent heart valve surgery at 9 institutions between 2017 and 2018. A risk prediction model was developed for operative mortality, defined as death within 30 days after surgery or during the same hospitalization. A statistical model was generated with a scoring system by multiple logistic regression analyses. The performance of the model was evaluated by its discrimination and calibration abilities. Results: Operative mortality occurred in 142 patients. The final regression models identified 13 risk variables. The risk prediction model showed good discrimination, with a c-statistic of 0.805 and calibration with Hosmer-Lemeshow goodness-of-fit p-value of 0.630. The risk scores ranged from -1 to 15, and were associated with an increase in predicted mortality. The predicted mortality across the risk scores ranged from 0.3% to 80.6%. Conclusion: This risk prediction model using a scoring system specific to heart valve surgery was developed from the KHVSR database. The risk prediction model showed that operative mortality could be predicted well in a Korean cohort.

• 한방재활의학과학회지
• /
• 제27권3호
• /
• pp.117-124
• /
• 2017

Objectives Collaboration medicine means cooperate with western medicine and traditional korean medicine to treat the one disease. In Korea, Interest in collaboration medicine is increasing, But the number of studies is scare. Therefore we will conduct collaboration medicine study for the low back pain. Methods This study composes prospective cohort registry study. If the patients who need collaboration medicine by doctor come, we will ask regist this study. And patient select collaboration treatment group and single treatment group. Total 120 patients will recruit from collaboration pilot project hospitals. Each group patient will observed 4 weeks. Telephone research will conducted after 1 month from the last follow up. During the treatment, patients are treated usual treatment type of each medicine. Primary outcome is NRS and secondary outcomes are EQ-5D and ODI. We will analyze difference of 1 week and 4 week outcome result. Conclusions This study is the first large sample size study effect of collaboration medicine in Korea for low back pain. We check present collaboration system and improve collaboration system. Aim of this study is to find the effectiveness collaboration medicine for low back pain in the real condition. And we expect this pilot study will provide the clinical collaboration information and basis.

• 한국음향학회지
• /
• 제19권5호
• /
• pp.20-26
• /
• 2000

화자 확인시스템에서 화자의 장기간 음성 변동에 대처하기 위해서는 작은 양의 데이터로써 화자 확인을 위한 HMM(hidden Markov model) 파라미터 갱신과 사전 문턱치 결정이 중요한 요소이다. 본 연구에서는 화자내 변이(mea-speaker variation)에 적응하는 모델 갱신방법과 이에 따른 문턱치 적응에 관한 방법을 제안한다. 제안하는 방법은 분기간 화자내 변이로 발생할 수 있는 오인식율을 Baum-Welch re-estimation을 통해 현재 화자 모델 파라미터에 새로운 음성 데이터를 적응시킴으로써 감소시킨다. 본 논문에서 제안하는 사전 문턱치 결정 방법은 기존의 월드 모델(world model) 방법과 군중 모델(cohort model) 방법의 하이브리드 형태로써 실험적으로 결정된다. 실험에 의해 모델 갱신을 하지 않은 경우보다 제안하는 모델 갱신방법의 화자 인식율이 우수함을 확인하였다. 또한, 사후 문턱치 결정에 의한 인식율과 제안한 사전 문턱치 결정에 의한 인식율의 차이가 근소함을 확인하였다.

• 한국임상수의학회지
• /
• 제16권2호
• /
• pp.422-427
• /
• 1999

We are proposed for the computation of disease frequency measures and of their associated variances from data collected through prospective study of multiple dynamic cohort (herds) with a National Animal Health Monitoring System (NAHMS) in Gyeongnam. We can be estimated and calculated the annual incidence density for a group of herds and the 1-month risk of disease from the same within herd measure of monthly incidence density. We are proposed that the choice of measure to be estimated depend on the intended use of the information. From results in this study, Our study demonstrate that risk estimates are appropriates for producers and clinic veterinarian making decisions at the animal or herd level. Incidence density measures are appropriate for extrapolation to reference populations used for state and regional-level decision making.

• Journal of Chest Surgery
• /
• 제55권5호
• /
• pp.378-387
• /
• 2022

Background: Atrial fibrillation (Afib) is a marker of increased cardiovascular morbidity and mortality. Owing to the increased prevalence of Afib in patients undergoing cardiac surgery, assessing the effect of Afib on postsurgical outcomes is important. We aimed to analyze the effect of preoperative Afib on clinical outcomes in patients undergoing cardiac surgery using a large surgical database. Methods: This retrospective cohort study was based on the national health claims database established by the National Health Insurance Service of the Republic of Korea from 2009 to 2015. Diagnosis and procedure codes were used to identify diseases according to the International Statistical Classification of Diseases, 10th revision. Results: We included 1,037 patients (0.1%) who had undergone cardiac surgery from a randomized 1,000,000-patient cohort, and 15 patients (1.5%) treated with isolated surgical Afib ablation were excluded. Of these 1,022 patients, 412 (39.7%), 303 (29.2%), and 92 (9.0%) underwent coronary artery bypass, heart valve surgery, and Cox-maze surgery, respectively. Preoperative Afib was associated with higher patient mortality (p=0.028), regardless of the surgical procedure. Patients with preoperative Afib (n=190, 18.6%) experienced a higher cumulative risk of overall mortality (hazard ratio [HR], 1.435; 95% confidence interval [CI], 1.263-2.107; p=0.034). Subgroup analysis revealed a reduced risk of overall mortality with Cox-maze surgery in Afib patients (HR, 0.500; 95% CI, 0.266-0.938; p=0.031). Postoperative cerebral ischemia or hemorrhage events were not related to Afib. Conclusion: Preoperative Afib was independently associated with worse long-term postoperative outcomes after cardiac surgery. Concomitant Cox-maze surgery may improve the survival rate.

• 한국시스템다이내믹스학회:학술대회논문집
• /
• 한국시스템다이내믹스학회 2006년도 추계학술대회 발표논문집
• /
• pp.49-69
• /
• 2006

본 논문은 선행연구인 정회성${\cdot}$전대욱 (2005)의 모형을 중심으로 선행연구에서 미처 다루지 못한 체계 변화 및 모형 확장 등에 대해 다루고 있다. 선행연구에서는 우리나라의 참게 복원사업에 대한 개체수 동태모형(population dynamics)과 자원 경제학적 이론모형을 근거로 생태${\cdot}$경제 통합시스템에 대한 동태모형을 도출하고 이를 통해 실증분석을 수행하였는데, 본 논문에서는 이 통합 모형에 있어서 밀도 제약(density restriction)과 공식 행위(cannibalistic behavior), 주민참여에 의한 환경개선 등 일련의 가정들에 대한 확장을 통해 보다 일반화된 통합체계 및 시스템 다이내믹스 분석을 제시한다. 이와 같은 모형 확장 및 파라메터의 내생화 등은 관련 피드백 루프들의 변형과 추가 등을 의미하며, 이와 같은 변화를 포함한 확장 모델을 제시하고 분석함으로써 참게 복원사업에 대한 보다 폭넓은 논의를 제시하고자 한다.

• 한국시스템다이내믹스연구
• /
• 제11권1호
• /
• pp.27-57
• /
• 2010

This article deals with an ecological-economic analysis of the 'Pasture Project of Kum River', which is the farming plan of mitten crabs using Jichun, a stream of the River Kum where the natural propagation of mitten crabs are blocked because of the estuary dam constructed in 1990. Toward analyzing the ecological and economic effects of the crab releasing and harvesting activities in Jichun, a two-stage cohort model of population dynamics with cannibalistic behaviors and density restrictions in biomathematics is adopted, despite of the current infertility in Kum, considering the opportunity of establishing dam fishways in the near future. This study moreover presents a method of parameter estimation especially with assuming a steady state of the ecosystem, and performs various analyses such as the risk measurement of climate change and the economic value of such fishways.

• 의료ㆍ복지 건축 : 한국의료복지건축학회 논문집
• /
• 제27권3호
• /
• pp.61-69
• /
• 2021

Purpose: Senior long-term care facilities are vulnerable to a cluster infection because of frequent physical contact, large group dining, communal living, and room sharing. This study aims to provide architectural improvement plans for a quarantine system in the facilities. Methods: Actual quarantine action data, guidelines from governments and institutes, in-depth interviews with facility staff are analyzed. Results: To prevent a cluster infection in the senior facilities, it is necessary to provide an architectural plan focusing on increasing the number of single rooms and isolation rooms, providing isolation rooms for staff, separation of a soiled room from a clean room, planing an entry vestibule and a visitor's room. Implications: It is important to analyze the existing condition of facilities that had been going through cohort isolation and provide the architectural solution to strengthen infection control.

• Korean Journal of Radiology
• /
• 제24권3호
• /
• pp.190-203
• /
• 2023

Objective: We aimed to assess and validate the radiologic and clinical factors that were associated with recurrence and survival after curative surgery for heterogeneous targetoid primary liver malignancies in patients with chronic liver disease and to develop scoring systems for risk stratification. Materials and Methods: This multicenter retrospective study included 197 consecutive patients with chronic liver disease who had a single targetoid primary liver malignancy (142 hepatocellular carcinomas, 37 cholangiocarcinomas, 17 combined hepatocellular carcinoma-cholangiocarcinomas, and one neuroendocrine carcinoma) identified on preoperative gadoxetic acid-enhanced MRI and subsequently surgically removed between 2010 and 2017. Of these, 120 patients constituted the development cohort, and 77 patients from separate institution served as an external validation cohort. Factors associated with recurrence-free survival (RFS) and overall survival (OS) were identified using a Cox proportional hazards analysis, and risk scores were developed. The discriminatory power of the risk scores in the external validation cohort was evaluated using the Harrell C-index. The Kaplan-Meier curves were used to estimate RFS and OS for the different risk-score groups. Results: In RFS model 1, which eliminated features exclusively accessible on the hepatobiliary phase (HBP), tumor size of 2-5 cm or > 5 cm, and thin-rim arterial phase hyperenhancement (APHE) were included. In RFS model 2, tumors with a size of > 5 cm, tumor in vein (TIV), and HBP hypointense nodules without APHE were included. The OS model included a tumor size of > 5 cm, thin-rim APHE, TIV, and tumor vascular involvement other than TIV. The risk scores of the models showed good discriminatory performance in the external validation set (C-index, 0.62-0.76). The scoring system categorized the patients into three risk groups: favorable, intermediate, and poor, each with a distinct survival outcome (all log-rank p < 0.05). Conclusion: Risk scores based on rim arterial enhancement pattern, tumor size, HBP findings, and radiologic vascular invasion status may help predict postoperative RFS and OS in patients with targetoid primary liver malignancies.

• 한국시스템다이내믹스연구
• /
• 제7권2호
• /
• pp.97-120
• /
• 2006

This paper deals with the extension of and discussion on the System Dynamics model (Jeong & Jeon, 2005) of river crabs in Korea. The previous model has been elaborated to empirically search for the optimal restoration and harvest rates of crabs in the Imjin River, on the basis of theoretical models of population dynamics in the field of bio-mathematics and environmental economics. In this paper, the authors tries to couple a series of new feedback loops related to density restrictions and cannibalistic behaviors with a stage-structured model of the crab ecosystem, and also to endogenize the parameter of baby crabs' survival that is caused by water quality improvement and income increase. Through these extensions and relaxations, the authors are able to argue about the strategic decision of the optimal rates additional considerations as well as the properties of the integrated system that was not covered in the previous paper.