• 구강회복응용과학지
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• 제32권4호
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• pp.280-292
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• 2016

목적: 이 연구의 목적은 임플란트의 생존율과 주위 변연골 수준을 후향적으로 평가하여, 술자의 임상적 경험을 포함한 요인들이 미치는 영향을 분석하고자 하였다. 연구 재료 및 방법: 2002년 1월부터 2009년 3월까지 강릉원주대학교치과병원 치주과에서 전공의가 2단계법으로 식립한 임플란트 중 5년 이상의 기록이 있는 146명의 420개 임플란트를 대상으로, 임플란트 탈락여부, 주위 골 소실량, 성별, 연령, 2형 당뇨, 흡연, 지대주 연결 형식, 표면 처리 방법, 직경, 식립 부위, 식립 당시 전공의 연차, 덮개 나사의 조기 노출, 보철학적 합병증, 동반된 골 이식 술식 등의 영향을 평가하였다. 결과: 최종 보철물 장착 후 5년간 누적생존율은 94.9% 이었다. 이원로지스틱회귀분석 결과, 흡연과 덮개 나사의 조기 노출이 실패율을 유의하게 증가시켰다. 다중회귀분석 결과, 흡연, 임플란트 지대주 연결 형식, 및 표면 처리 방법이 임플란트 주위 변연골 수준 변화에 유의한 영향을 주었다. 술자의 임상경험을 반영하기 위한 식립 당시의 전공의 수련 연차는 임플란트의 실패와 유의한 연관성은 보이지 않았다(P = 0.171). 결론: 흡연, 덮개 나사의 조기 노출, 지대주 연결 형식 및 표면 처리 방법이 임플란트의 성공과 유의한 상관관계를 보이는 것으로 생각된다.

• Journal of the Korean Data and Information Science Society
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• 제23권2호
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• pp.257-269
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• 2012

최근 글로벌 금융위기와 중소기업들의 연이은 도산으로 인해 국내 중소기업들의 구조조정에 대한 논의가 활발히 진행되고 있다. 이에 본 논문에서는 신용보증기금에 등록된 중소기업 자료에 대하여 업종별 생존율 동향을 비교분석하였다. 이때 생존율의 차이는 로그순위 검정과 윌콕슨의 검정통계량을 사용하여 분석하였다. 또한 재무변수들을 이용하여 중소기업의 업종별 콕스 회귀분석을 실시하였다. 그 결과, 도소매업과 서비스업이 경공업과 중공업, 건설업에 비하여 생존율이 높았으며, 건설업의 경우 생존율이 가장 낮음을 알 수 있었다. 또한, 업종별로 유의한 재무변수를 살펴보면, 건설업은 자기자본비율, 유동비율이 커질수록 부도율이 감소하는 반면에 차입금의존도가 커질수록 부도율이 증가하였다. 경공업은 자기자본비율, 총자산 순이익률이 커질수록, 도소매업은 자기자본비율, 유동비율이 커질수록 부도율이 감소하였다. 중공업은 자기자본비율, 총자산 순이익률, 유동비율이 커질수록 부도율이 감소하였지만 결합지표가 커질수록 부도율이 증가하였다. 마지막으로, 서비스업은 유동비율이 커질수록 부도율이 감소하였다.

• 응용통계연구
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• 제15권2호
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• pp.233-250
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• 2002

Cox의 비례위험모형(proportional hazards model)은 생존자료(survival data)에 대한 회귀모형으로 경제학 및 의·공학을 비롯한 여러 응용 분야에서 가장 널리 쓰이고 있는 모형 중 하나이다. 그러나, 이 모형은 일반선헝모형에 비해 잔차 분석을 통한 회귀 진단의 연구가 널리 알려져 있지 않아, 국내의 실제 자료 분석에서는 잔차 분석에 대한 활용이 거의 이루어지지 않고 있는 실정이다. 이에 본 논문에서는 그 동안 제안된 여러 잔차들을 비교 분석하고, S-plus 프로그램을 이용한 PBC(primary biliary cirrhosis) 자료분석을 통해 각 잔차들의 의미를 고찰하고자 한다.

• 응용통계연구
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• 제20권2호
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• pp.313-322
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• 2007

오염이 있는 생존자료에서 여러 가지 회귀뎁스(regression depth)를 비교 연구하였다. 중도절단 자료에서 회귀뎁스에 대한 정의는 Park과 Hwang(2003)의 반공간회귀뎁스(halfspace regression depth)와 Park(2003)의 심플리셜 회귀뎁스(simplicial regression depth)가 있다. 본 논문은 Hubert 등(2001)이 제안한 사영회귀뎁스(projection regression depth)를 생존자료에서 사용하는 방법을 제시하고 이 방법과 기존의 뎁스기반 회귀모형과의 비교를 다양한 오염 상황에서 실시하였다.

• Journal of Gastric Cancer
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• 제16권2호
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• pp.78-84
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• 2016

Purpose: The aim of this study was to determine whether surgical resection of the primary tumor contributes to survival in patients with metastatic gastric cancer. Materials and Methods: A total of 288 patients with metastatic gastric cancer from the Akdeniz University, Antalya Training and Research Hospital, and the Meram University of Konya database were retrospectively analyzed. The effect of primary tumor resection on survival of patients with metastatic gastric cancer was investigated using the log-rank test. Kaplan-Meier survival estimates were calculated. Multivariate analysis was performed using Cox proportional hazards regression modeling. Results: The median overall survival was 12.0 months (95% confidence intewrval [CI], 10.4~13.6 months) and 7.8 months (95% CI, 5.5~10.0 months) for patients with and without primary tumor resection, respectively (P<0.001). The median progression-free survival was 8.3 months (95% CI, 7.1~9.5 months) and 6.2 months (95% CI, 5.8~6.7 months) for patients with and without primary tumor resection, respectively (P=0.002). Conclusions: Non-curative gastrectomy in patients with metastatic gastric cancer might increase their survival rate regardless of the occurrence of life-threatening tumor-related complications.

• 한국응급구조학회지
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• 제25권1호
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• pp.205-221
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• 2021

Purpose: This paper is to determine whether automatic defibrillators (AEDs) deployed across communities make a contribution to prevent death in patients with acute cardiac arrest out-of-hospital. Methods: A total of 30,179 cases of cardiac arrest investigation data from the Korea Centers for Disease Control and Prevention was matched to those on emergency medical statistics drawn from annual report for the 2018 Central Emergency Medical Center, and statistics from the National Statistical Office in 2018. Results: Multiple logistic regression analyses revealed that availability of emergency medical resources across associated with different survival rates at emergency room after taking variability of the patient's personal characteristics and episodic situational characteristics held constant. The survival rate was 1.71 times higher for patients living in communities with more than 105 AEDs avaiable per 100,000 inhabitants than for those living in communities with less than 55 AEDs. Conclusion: The survival-related factors of patients with acute cardiac arrest that occurred out-of-hospital were found to be associated with patients' and episodic situational characteristics. The hospital stage were found to be associated with patients characteristics and episodic situational characteristics, The variability of AED available in a community has an impact on survival rate after emergency room treatment.

• 아태비즈니스연구
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• 제12권1호
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• pp.25-39
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• 2021

Purpose - This study aims to examine whether family firm governance is related to long-term corporate survival. To find out whether and why family firms have higher chances of long-term survival compared to non family firms, this study analyzes the relationship between some governance characteristics that are prevalent in family firms and corporate long-term viability. Design/methodology/approach - This study utilizes a sample of 285 family firms listed on the Korea Stock Exchange (KSE) to probe the influence of governance characteristics on corporate survival. This study conducts Cox proportional hazard regression analysis to estimate the influences on the survival duration. Findings - The results indicate that firms with particular governance characteristics show higher long-term survivability. Specifically, the probability of firm's long-term survival is increased when the CEO is the largest shareholder, which may be related to CEO's stewardship attitudes. Research implications or Originality - This study has significance in that it examines the direct causal variables that enhance long-term corporate viability through a large scale empirical examination. Also, the study findings provide some clues as to why certain family firms outlive non-family firms.

• Journal of the Korean Statistical Society
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• 제26권3호
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• pp.333-354
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• 1997

Computational algorithms to calculate M-estimators and rank estimators of regression parameters from left-truncated and right-censored data are developed herein. In the case of M-estimators, new statistical methods are also introduced to incorporate leverage assements and concomitant scale estimation in the presence of left truncation and right censoring on the observed response. Furthermore, graphical methods to examine the residuals from these data are presented. Two real data sets are used for illustration.

• 농업과학연구
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• 제41권2호
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• pp.135-139
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• 2014

Pathogenic E. coli associated post-weaning diarrhea (PWD) and edema disease are common diseases in commercially-housed weanling pigs. An enterotoxigenic E. coli (ETEC) oral challenge model has been used to mimic the physiological responses observed in commercial conditions. However, an oral challenge procedure has two major limitations: (1) the ETEC cell density is unknown at the point of oral inoculation, and (2) blending ETEC with traditional TSB (trypticase soy broth) is not palatable and hence decreases acceptability by piglets. Therefore, the purposes of this study were to (1) establish a regression equation that can be used for estimation of ETEC concentration in dilution media using the spectrophotometric measurement of cell density; and (2) examine survival of ETEC after blending either with TSB, sweetener or dextrose. A strain of ETEC (serogroup beta-hemolytic E. coli O149; K91; F4; toxins LT, STa, STb) was grown in TSB for 3.5 hours, centrifuged, the supernatant was discarded, and the ETEC pellet was then blended either with TSB (100 mL), sweetener (60 mL TSB + 40 mL fruit flavored concentrate), or dextrose (50 mL TSB + 50 mL dextrose; 0.5g/mL dextrose). Cell density was measured using the colorimetric method and also plated on a 5% sheep blood agar for counting of ETEC colony forming units at 0, 5, 35, 65 and 125 min after blending. The optical density at 600 nm explained 83% of ETEC colony forming units, indicating that the established linear equation (y= 6E+08x - 4E+07, P<0.004) can be used for robust quantification of ETEC cell density in TSB, sweetener and dextrose media. When ETEC was blended with sweetener and dextrose, survival of ETEC was decreased by 45% and 72% within 5 min post-blending. Therefore, further research is required to find out the suitable medium that has potential to improve palatability without compromising survival of ETEC.

• Asian Pacific Journal of Cancer Prevention
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• 제14권5호
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• pp.2805-2809
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• 2013

Objective: This study aimed at investigating whether the orphan nuclear receptor NR4A2 is significantly associated with clinicopathologic features and overall survival of patients with nasopharyngeal carcinoma (NPC). Methods: Immunohistochemistry was performed to determine NR4A2 protein expression in 84 NPC tissues and 20 non-cancerous nasopharyngeal (NP) tissues. The prognostic significance of NR4A2 protein expression was evaluated using Cox proportional hazards regression models and Kaplan-Meier survival analysis. Results: We did not find a significant association between total NR4A2 expression and clinicopathological variables in 84 patients with NPC. However, we observed that high cytoplasmic expression of NR4A2 was significantly associated with tumor size (T classification) (P = 0.006), lymph node metastasis (N classification) (P = 0.002) and clinical stage (P = 0.017). Patients with higher cytoplasmic NR4A2 expression had a significantly lower survival rate than those with lower cytoplasmic NR4A2 expression (P = 0.004). Multivariate Cox regression analysis analysis suggested that the level of cytoplasmic NR4A2 expression was an independent prognostic indicator for overall survival of patients with NPC (P = 0.033). Conclusions: High cytoplasmic expression of NR4A2 is a potential unfavorable prognostic factor for patients with NPC.