• Clinical and Experimental Pediatrics
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• 제53권7호
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• pp.745-752
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• 2010

Purpose: There is currently little evidence to support intravenous immune globulin (IVIG) therapy for pediatric myocarditis. The purpose of our retrospective study was to assess the effects of IVIG therapy in patients with presumed myocarditis on survival and recovery of ventricular function and to determine the factors associated with its poor outcome. Methods: We reviewed all consecutive cases of patients with myocarditis with left ventricular dysfunction verified by echocardiogram who had visited 3 university hospitals between January 2000 and September 2009. These patients were divided into 2 groups. Group 1 consisted of 23 patients (69.6%) who received IVIG alone or IVIG in combination with steroids, and group 2 consisted of 10 patients (30.3%) who received neither IVIG nor other immunosuppressive agents. Clinical manifestations, laboratory results, echocardiographic findings, and outcomes were compared between these 2 groups. Results: One year after the initial presentation, the difference in the probability of survival did not show statistical significance in IVIGtreated patients ($P$=0.607). Of the echocardiographic parameters on admission, a shortening fraction of less than 15% was associated with unremitting cardiac failure. Furthermore, anemic patients were more likely to have elevated N-terminal fragment levels of the B-type natriuretic peptide (NT-proBNP) in the progressed group ($P$=0.036). Conclusion: There was no difference between the IVIG-treated patients and the control patients in the degree of recovery of left ventricular function and survival. Prospective, randomized, clinical studies are needed to elucidate the effects of IVIG treatment during the acute stage of myocarditis on ultimate outcomes.

• 한국산학기술학회논문지
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• 제22권2호
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• pp.459-467
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• 2021

본 연구는 청소년의 최초 지위비행 발생시점을 비연속 생존분석을 통해 규명하고, 최초 지위비행에 미치는 영향요인을 분석하는데 목적이 있다. 분석은 한국아동청소년패널조사(Korean Children & Youth Panel Survey)의 중1패널 5개년 자료를 활용하였으며, 분석 대상 학생 수는 2,277명(남학생 1,126명, 여학생 1,151명)이다. 주요 분석결과는 다음과 같다. 첫째, 최조 지위비행 발생에 대한 위험확률은 중2때 16.6%로 가장 높았으며, 중3때는 다소 감소하였으나 전반적으로 학년이 높아지면서 지속적으로 증가하였다. 둘째, 우울, 공격성과 같은 청소년의 심리, 정서 요인이 최초 지위비행 시점에 유의하게 영향을 미쳤다. 셋째, 부모의 부정적 양육방식인 학대는 비행에 유의한 영향을 미친 반면 방임은 유의하지 않았다. 넷째, 청소년 주변의 비행친구는 최초 지위비행에 영향을 미치는 중요한 요인이었다. 다섯째, 학교요인 중 학습활동 적응, 학교규칙 적응, 교우관계 적응은 지위비행에 영향을 미친 반면 교사관계 적응은 유의하지 않았다. 청소년의 최초 지위비행에 대한 발생시점과 영향요인을 분석한 결과 청소년의 지위비행 예방을 위해 초기 개입이 중요하며, 따라서 이에 대한 적절한 교육과 지원이 필요하다.

• 척추신경추나의학회지
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• 제17권2호
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• pp.131-139
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• 2022

Objectives This study aimed to analyze the medical utilization of low back pain (LBP) patients after back surgery and estimate the medical costs of Korean and Western medicine collaborative treatment, odds ratio, and hazard ratio between the two groups using the 2019 Health Insurance Review and Assessment Service-National Patient Sample (HIRA-NPS-2019). Methods Data management and descriptive analysis, logistic regression, and survival analysis were conducted for defining and estimating the LBP patients after back surgery in the NPS 2019 dataset. Results A total of 216,424 patients out of 991,189 were identified as having LBP. Among the patients with LBP, 1,734 were treated with surgery while 214,690 were not. Among those who had surgery, 937 were treated with conventional treatments only and 797 underwent Korean medicine treatments. The odds ratio of the logistic regression analysis was 0.7129, suggesting that Korean medical treatment experience group had a 28.7% lower risk of reoperation than the Western medical treatments only group. The hazard ratio of the survival analysis was 0.9145; thus, the risk probability of reoperation was estimated to be approximately 8.55% lower. The 50% risk of reoperation was 69 days (0.5044) for the conventional group, and 97 days (0.5008) for the Korean medical group in the survival analysis using the Kaplan-Meier graph. Conclusions These results could be utilized in future studies in conducting economic evaluation for estimating cost-effectiveness of Western medicine and Korean medicine treatment compared to Western medicine alone in LBP patients after back surgery in a South Korean perspective. mended and should be applied while taking the necessary precautions.

• 한국간담췌외과학회지
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• 제26권1호
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• pp.47-57
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• 2022

Backgrounds/Aims: It is challenging to assess the efficacy of partial hepatectomy (PH) as a treatment option for patients with hepatocellular carcinoma (HCC) accompanied by cirrhosis. This study aimed to determine the cure fraction of PH for HCC accompanied by cirrhosis compared to that for HCC without cirrhosis. Methods: A systematic review was performed on outcomes of previous studies that compared recurrence-free survival (RFS) after PH in patients with HCC with or without cirrhosis. A meta-analysis was conducted to obtain the cumulative hazard ratio for two patient groups: cirrhosis and non-cirrhosis. Cure fractions after PH in both groups were determined using a cure model analysis. Results: A total of 18 studies were eligible for meta-analysis and 13 studies were selected for the cure model analysis. The cumulative hazard ratio for RFS of the cirrhosis group compared to that of the non-cirrhosis group was 1.66 (95% confidence interval [CI], 1.43-1.93). Survival data of 3,512 patients in both groups were reconstructed from survival curves of original articles for cure model analysis. The probability of being statistically cured after PH for HCC was 14.1% (95% CI, 10.6%-18.1%) in the cirrhosis group lower than that (32.5%) in the non-cirrhosis group (95% CI, 28.6%-36.4%). Conclusions: The prognosis after PH for HCC accompanied by cirrhosis is inferior to that for HCC without cirrhosis. However, a cure can be expected for one-seventh of patients with HCC accompanied by cirrhosis after PH.

• ETRI Journal
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• 제38권5호
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• pp.1019-1029
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• 2016

The probability hypothesis density (PHD) filter is an effective means to track multiple targets in that it avoids explicit data associations between the measurements and targets. However, the target birth intensity as a prior is assumed to be known before tracking in a traditional target-tracking algorithm; otherwise, the performance of a conventional PHD filter will decline sharply. Aiming at this problem, a novel target birth intensity scheme and an improved measurement-driven scheme are incorporated into the PHD filter. The target birth intensity estimation scheme, composed of both PHD pre-filter technology and a target velocity extent method, is introduced to recursively estimate the target birth intensity by using the latest measurements at each time step. Second, based on the improved measurement-driven scheme, the measurement set at each time step is divided into the survival target measurement set, birth target measurement set, and clutter set, and meanwhile, the survival and birth target measurement sets are used to update the survival and birth targets, respectively. Lastly, a Gaussian mixture implementation of the PHD filter is presented under a linear Gaussian model assumption. The results of numerical experiments demonstrate that the proposed approach can achieve a better performance in tracking systems with an unknown newborn target intensity.

• Journal of the Korean Data and Information Science Society
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• 제28권2호
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• pp.349-359
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• 2017

본 논문에서는 미국 국립암연구소의 SEER 프로그램에서 제공하는 우측 대장암 3기 자료에 Cox 비례위험모형을 적합하여 생존분석을 하였다. 우측 대장암 3기 환자의 사망률에 유의한 영향을 미치는 공변량들을 파악하고, 관심있는 공변량들을 가진 환자의 생존율을 추정하였다. Schoenfeld 잔차를 기반한 검정과 Schoenfeld 잔차 도표, $log[-log\{{\hat{S}}(t)\}]$ 도표를 이용하여 분석에 사용된 공변량들이 비례위험 가정을 만족함을 확인하였다. 적합된 Cox 비례위험모형의 타당성을 검증하기 위해 10-fold 교차 검증을 이용하여 calibration 도표와 시간에 의존하는 ROC 곡선 아래 면적을 계산하였다. 이를 통해 적합된 Cox 비례위험모형의 타당성을 확인하였다.

• Journal of Chest Surgery
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• 제20권2호
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• pp.281-288
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• 1987

A total and consecutive 163 patients underwent cardiac valve replacement using the Hancock porcine xenograft cardiac valves from 1 976 to 1984. Of 198 substitute valves, 177 were the Hancock valves. One hundred twenty-nine patients[79.1%] had single valve replacement: MVR 118, AVR 8 and TVR 3; 33[20.3%] had double valve replacement: MVR+AVR 27 and MVR+TVR 6; and a single case had triple valve replacement. Other surgical procedures were added in 34 patients. The operative mortality rate within 30 days of surgery was 6.1%, and it was, however, 4.2%, with single MVR. Late mortality rate was 6.7% or 1.95%/patient-year of a linealized mortality rate. Early survivors of 153 patients were followed up for a total of 565.1 patient-years [a mean of 44.3*27.1 months]. The linealized annual complication rates were: 1.95% emboli/patient-year, 0.89% bleeding/patient-year 1.24% endocarditis/patient-year, and 4.25% overall failure/patient-year. Primary tissue failure occurred at a rate of 1.59%/patient-year. The actuarial survival rates including operative mortality were 87.0*4.1% and 77.3*6.6% at 5 and 11 years after surgery respectively. The probability of freedom from thromboembolic complication of 89.2*3.4% at 5 years after surgery lasted unchanged upto 11 years. The probability of freedom from overall valve failure was 81.3*4.5% at postoperative 5 years, and it dropped down to 26.2*19.4% at 11 years, although the latter was statistically insignificant because of a small number of patients entering into the years approaching the follow-up end. However, the probability of freedom from the primary tissue failure was 81.3*10.6% at postoperative 9 years, which coincides closely with the speculated rate of tissue degeneration of about 20% in 10 years. These clinical results confirm the low thrombogenicity of the Hancock porcine valve and the reasonable failure rate of tissue degeneration.

• 정보처리학회논문지B
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• 제12B권4호
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• pp.429-436
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• 2005

본 논문에서는 유전자 알고리즘의 일반적인 문제점인 과도한 저장공간의 소모와 탐색의 비효율성을 줄이기 위해 PBIL을 이용한 단순한 스테레오 정합 기법을 제안한다. PBIL은 확률벡터에 기반해서 통계적 탐색과 경쟁학습을 이용하는 변종 유전자 알고리즘이며 확률벡터의 사용으로 인해 직렬 및 병렬 유전자 알고리즘군에 비해 단순한 구조를 가진다. 본 논문에서는 이 PBIL을 스테레오 정합 환경에 맞게 변형 및 단순화시켜 정합 알고리즘을 개발한다. 높은 적응성을 갖는 염색체는 생존 확률 또한 높다는 진화 법칙을 보존하면서 유전자 풀, 염색체 교차 및 유전자 돌연변이를 제거할 수 있으며 그 결과 저장공간을 줄이고 정합 규칙을 간소화하여 계산 비용을 감소시킬 수 있다. 추가적으로 다해상도 정합 기법처럼 넓은 영역의 변이 일관성을 획득하기 위해 변이 연속성에 대한 이웃들의 거리를 제어하는 방식을 추가하여 고정된 작은 정합창을 사용하면서 안정된 결과를 얻을 수 있게 한다. 마지막으로 단순한 시스템에 적용될 수 있게 하기 위해서 확률벡터를 사용하지 않는 제안한 알고리즘의 소형 대안 기법을 제시한다.

• 벤처창업연구
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• 제19권3호
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• pp.155-172
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• 2024

COVID-19 팬데믹은 인류에게 막대한 위기를 안겨준 것은 물론, 기업 생존에 중대한 영향을 미쳤다. 인간 생명을 보호하기 위한 사회적 거리두기와 글로벌 봉쇄 정책이 역설적으로 기업 생존 환경을 악화시킨 것이다. 이에 따라 외부 자원을 통해 경쟁 우위를 확보하려던 기업들은 외부와의 단절로 예기치 못한 도전에 직면하게 되었다. 이러한 상황에서 COVID-19 팬데믹 초기의 선행연구들은 전통적인 재무 요인을 통해 경영 성과를 재차 진단하는 데 그쳤다. 이에 본 연구는 자원기반관점에서 위기 상황에서 창업자의 역량이 경영 성과를 향상하고 이를 통해 창업기업의 생존 가능성을 높이는 중요한 요인임을 규명하고자 하였다. 구체적으로, 기술평가를 통해 정책금융을 제공하는 기술보증기금(KOTEC)이 2016년에 평가한 1,127개 창업기업을 대상으로 2019년 말의 경영 성과를 측정하였다. 그 이후 엔데믹을 선언한 시점인 2023년 6월 말 연구 대상 기업의 생존 상태를 확인하여 창업자 역량과 기업생존과의 관계에서 경영 성과의 매개 역할을 규명하는 실증 연구를 수행하였다. 이를 위해 창업자 역량의 하위요인으로는 기술적, 재무적, 마케팅 역량으로 정의하였고, 매출액 증가율과 고용 증가율을 경영 성과의 하위요인으로 보았다. 실증분석 결과, 창업자의 기술적, 재무적 역량이 창업기업의 경영 성과와 생존에 모두 긍정적인 영향을 미쳤으며, 매출액 증가율과 고용 증가율이 기술적 역량과 기업 생존 사이를 매개하였다. 하지만, 창업자의 재무적 역량은 고용 증가율을 통해서만 창업기업의 생존에 긍정적인 영향을 미치는 것으로 나타났다. 본 연구는 COVID-19 팬데믹 상황에서 창업기업의 생존요인을 규명한 국내 최초의 연구로서, 자원기반관점에서 창업자의 역량이 중요한 생존요인이라는 이론적, 실무적 논의 확대에 기여할 것으로 기대한다.

• 한국국방경영분석학회지
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• 제6권2호
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• pp.129-149
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• 1980

In medical follow-up, equipment lifetesting, various military situations, and other fields, one often desires to calculate survival probability as a function of time, p(t). If the observer is able to record the time of occurrence of the event of interest (called a 'death'), then an empirical, non-parametric estimate may simply by obtained from the fraction of survivors after various elapsed times. The estimation is more complicated when the data are truncated, i.e., when the observer loses track of some individuals before death occurs. The product-limit method of Kaplan and Meier is one way of estimating p(t) when the mechanism causing truncation is independent of the mechanism causing death. This paper proposes jackknife estimators of logistic trans-formation and compares it to the product-limit method. A computer simulation is used to generate the times of death and truncation from a variety of assumed distributions.