• Journal of Chest Surgery
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• 제20권3호
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• pp.528-535
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• 1987

A clinical study was performed on 164 cases of PDA experienced at the Dept. of Thoracic and Cardiovascular Surgery of Pusan National University Hospital during 6 years from Jan. 1981 to Dec. 1986. It was shown that the PDA was a female-dominant heart disease [male to female ratio, 1:2.8] and two most common symptoms were frequent URI [45.6%] and exertional dyspnea [36.7%]. Continuous machinery murmurs were detected in 143 cases [87.2%], increased pulmonary vascularities [89.0%] and cardiomegalies [63.4%] by chest X-ray. The signs of LVH [43.9%], RVH [3.7%] and BVH [4.9%] were noted on the EKG. Cardiac catheterizations were performed on 67 out of 164 patients and the mean systolic pulmonary artery pressure was 48mmHg [range: 18-131mmHg] and the mean Qp/Qs was 3.1 [range:1.2-8.5] and Rp/Rs below 0.25 was 83.6%. Associated cardiac anomalies were VSD [7.9%], ASD [3.0%], pulmonary valvular stenosis [2.4%] and left persistent SVC [2.4%]. Operative methods were as follows; ligations [145; 88.4%] and divisions [6;3.7%] were performed through the left posterolateral thoracotomies without mortality and the remained cases [13;8.0%] were managed under the cardiopulmonary bypass because of the associated cardiac anomalies. Atelectasis [4.9%] and pneumonia [4.3%] were most frequent postoperative complications and the overall mortality rate was 2.4% [4 out of 164 cases].

• 한국통신학회논문지
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• 제34권1C호
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• pp.9-14
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• 2009

본 논문에서는 매개 변수가 (N,M,L,1)인 특정 성질을 가진 이진 낮은 상관 구역 수열균(LCZ sequence)를 이용하여 매개 변수가 (2N,2M,L,2)인 4진 낮은 상관 수열군을 생성하는 방법을 제시한다. 본 논문에서 이용하는 이진 낮은 상관 수열군은 balance property를 가지고 있어야 하며, 주기 N이 $N{\equiv}3$ mod 4이어야 하고, 특정한 상관 특성을 가져야 한다. 새로 제안된 생성법은 특정 성질을 가진 이진 낮은 상관 수열군을 이용하여 이진 낮은 상관 수열군을 생성한 Kim, Jang, No, and Chung의 생성법을 응용한 것이다.

• Journal of Chest Surgery
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• 제19권4호
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• pp.627-632
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• 1986

This report describes our 17-years experience with intracardiac repair in 123 patients older than 15 years with tetralogy of Fallot. Major clinical manifestation was cyanosis and clubbing [102 Pts], but other minor associated manifestation were infective endocarditis, pulmonary tuberculosis, brain abscess, congestive heart failure, nephrotic syndrome, and tuberculous spondylitis. Prior palliative shunts had been performed in 10 patients. Preoperative hemoglobin ranged from 9.7 gm/dl to 25 gm/dl [mean 19 gm/dl]. The type of ventricular septal defect were typical perimembranous type, and total canal defect [13%]. The right ventricular outflow tract obstruction was due to combined [58.5%], infundibular [35%], and valvular stenosis [6.5%]. Transannular patch was used in 17% of patients. Hospital mortality was 9.8% in overall, but decreased to 1.7% since 1982. There was two late death [12 year actuarial survival [97%] due to fulminant hepatitis, residual abnormalities [PS, VSD]. Ninety two percent of survivors at follow-up are asymptomatic and leading an active normal life. Residual ventricular septal defect was detected with radionuclide single pass study in 15.3% of patients but almost cases were Qp/Qs less than 1.5, and only two patients had been candidates for reoperation.

• 한국조명전기설비학회지:조명전기설비
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• 제10권4호
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• pp.85-92
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• 1996

본 논문에서는 현수애자의 경년변화 분석을 위해 과전파괴 시험과 장기강도 기계적 하중시험을 신품과 사용품에 대하여 비교, 시험하였다. 현수애자의 경년변화에 따라 애자표면 온도가 대기보다 약 2[$^{\circ}C$] 상승에서 약 7~8[$^{\circ}C$] 상승이 발생하였고, 접착제로 사용한 포틀랜드 시멘트의 오토크래브 팽창율도 경년변화 사고가 많은 시료(오토크래브 팽창율의 측정치 :0.37[%]) 가 사고가 적은 시료(오토크래브 팽창율 : 0.1[%])보다 높게 나타났다. 또한, 신품보다 사용품의 품질관리지수 Qs와 인장강도가 현저히 저하됨을 알 수 있어, 우리나라의 기후조건에 맞도록 경년변화 시험 기준 개정도 요구된다.

• Journal of Chest Surgery
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• 제19권1호
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• pp.25-34
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• 1986

Recently, radionuclide angiocardiogram is one of the most common procedure for assessment of ventricular performance due to its distinctive advantages such as safety, accuracy, and ease of repeated studies. Also, measurement and comparison between pre and postoperative left ventricular ejection fraction [LVEF] are meaningful for assessing the severity of myocardial damage which occurred during open heart surgery and the status of myocardial recovery. We obtained pre and post operative LVEF using radionuclide angiocardiogram on 30 patients composed of atrial septal defect, ventricular septal defect, cyanotic congenital heart disease, and valvular heart disease who undergone the open heart surgery from March to august 1984. The study revealed that ventricular septal defect and mitral valvular heart disease showed 8.1% and 6.2% decreases of postoperative LVEF, respectively. But, there are little increases of postoperative LVEF in the atrial septal defect and cyanotic congenital heart disease. In ventricular septal defect, each group of Qp/Qs over 2.0 and systolic pulmonary artery pressure over 50mmHg showed significant 17% and 14.7% decreases of postoperative LVEF, respectively. Considering the duration of the aortic cross clamping times and closing methods of VSD, each group of duration over 30 min. and of patch closure showed 13.9% and 14.2% decreases of LVEF between pre and postoperative status respectively which was significant finding statistically.

• Wind and Structures
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• 제37권1호
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• pp.57-78
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• 2023

In this study, a generalized three-degree-of-freedom (3-DoF) analytical model is formulated to predict linear aerodynamic instabilities of a prism under quasi-steady (QS) conditions. The prism is assumed to possess a generic cross-section exposed to turbulent wind flow. The 3-DoFs encompass two orthogonal horizontal directions and rotation about the prism body axis. Inertial coupling is considered to account for the non-coincidence of the mass center and the rotation center. The aerodynamic force coefficients-drag, lift, and moment-depend on the Reynolds number based on relative flow velocity, angle of attack, and the angle between the wind and the cable. Aerodynamic forces are linearized with respect to the static equilibrium configuration and mean wind velocity. Routh-Hurwitz and Liénard and Chipart criteria are used in the eigenvalue problem, yielding an analytical solution for instabilities in galloping and static divergence types. Additionally, the minimum structural damping and stiffness required to prevent these instabilities are numerically determined. The proposed 3-DoF instability model is subsequently applied to a conductor with ice accretion and a full-scale dry inclined cable. In comparison to existing models, the developed model demonstrates superior prediction accuracy for unstable regions compared with results in wind tunnel tests.

• 한국미생물·생명공학회지
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• 제37권3호
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• pp.248-257
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• 2009

Vibrio harveyi 쿼럼 센싱 (quorum sensing; QS) 신호전달에 대한 저해제들이 주 신호물질인 N-3-hydroxybutanoyl-L-homoserine lactone(3-OH-$C_4$-HSL)의 분자 구조를 변형함에 의해 개발되었다. 일련의 구조 변형체들인 N-(3-hyoxysulfonyl)-L-homoserine lactones(HSHLs)들은 고체상 유기합성법 (solid-phase organic synthesis method)으로 합성되었다. 이 물질들의 생체내 쿼럼 센싱 저해능이 V. harveyi 발광을 이용한 bloassay를 system에 의해 측정되었을 때, 모두 의미있는 저해효과를 보여주었다. 이 물질들과 3-OH-$C_4$-HSL 수용체 단백질인 LuxN 사이의 상호작용을 분석하기 위하여 LuxN의 신호 결합 부위를 다른 acyl-HSL 결합 단백질들과의 유사성에 기초하여 시험적으로 결정하였다. 이 추정 신호결합 부위의 부분적 삼차구조를 ORCHESTRA program을 이용하여 예측하였으며, 이 부위 내에서 3-OH-$C_4$-HSL와 HSHLs의 결합 형태와 에너지를 계산하였다. 이렇게 모델링을 통해 얻어진 결과와 생체 내 bioassay를 통해 얻어진 결과의 비교를 통해, 수용체 단백질과 그 리간드 사이의 상호 작용에 관한 in silica 해석이 특히 단백질의 삼차 구조에 대한 정보가 제한적인 경우에 보다 나은 저해제 개발을 위한 유용한 방법이 될 수 있음을 제안한다.

• The Journal of Asian Finance, Economics and Business
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• 제7권5호
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• pp.185-194
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• 2020

The study aims to identify and measure factors affecting the perception of the selling price of luxury apartments in Hanoi. We conducted a questionnaire consisting of 29 observation variables with a 5-point Likert scale. Independent variables were measured from 1 "without effect" to 5 "strongly". Based on the desk review and results of interviews, a total of 500 questionnaires were sent to research participants for collection; 458 of them met standard and were subject to be analyzed. This study employs Cronbach's Alpha test, and regression model. The results of Exploratory Factor Analysis (EFA) and Multiple Regression Analysis (MRA) identify five main determinants influencing the perception of the selling price of luxury apartments in Hanoi, including Physical characteristics of a luxury apartment (PC); Location and position of an apartment (LP); Surrounding Area (SA); Quality of service provided by managers; (QS) and Demographics factor (DF). Based on the findings, some recommendations have been proposed to help the firm leaders design appropriate personnel policies for creating better price satisfaction for customers in the future. On this basis, the authors propose a number of recommendations to improve the quality of luxury apartments, thereby contributing to the development of the market for luxury apartments in Hanoi.

• 제어로봇시스템학회논문지
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• 제12권5호
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• pp.411-418
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• 2006

There are mainly two types of bang-bang controllers for nominal linear time-invariant (LTI) system. Optimal bang-bang controller is designed based on optimal control theory and suboptimal bang-bang controller is obtained by using Lyapunov stability condition. In this paper, the suboptimal bang-bang control method is extended to LTI system involving both control input saturation and structured real parameter uncertainties by using Lyapunov robust stability condition. Two robust optimal bang-bang controllers are derived by minimizing the time derivative of Lyapunov function subjected to the limit of control input. The one is developed based on the classical quadratic stability(QS), and the other is developed based on the affine quadratic stability(AQS). And characteristics of the two controllers are compared. Especially, bounds of parameter uncertainties which theoretically guarantee robust stability of the two controllers are compared quantitatively for 1DOF vibrating system. Moreover, the validity of robust optimal bang-bang controller based on the AQS is shown through numerical simulations for this system.

• 한국자기학회지
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• 제9권3호
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• pp.143-148
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• 1999

Spin-Peierls(SP) 전이를 하는 CuGeO3에서 Cu 이온과 Ge 이온을 자성 이온인 Fe 이온으로 일부 치환시킨 Cu1-xGe1-yFex+yO3계를 제조하여 전이온도 전후에서 자기적 특성과 결정학적 특성의 변화를 밝히기 위하여 자기감수율과 Mossbauer 스펙트럼을 측정 분석하였다. 결정구조는 모든 시료가 직방정계(orthorhombic)였고 격자 상수는 Fe의 치환량이 증가할수록 a축과 c축만 약간 감소하였다. 온도를 내리면서 측정한 자기감수율의 값이 12.5K 근처에서 급격히 감소하는 SP 전이를 나타냈는데 이 온도는 Fe의 치환량이 많아질수록 약간씩 낮아졌다. Mossbauer 스펙트럼은 Fe3+ 이온에 의한 두 개의 Zeeman sextet와 한 개의 이중선이 중첩되어 나타났는데 특히 SP 전이 온도(Tsp)에서 Mossbauer변수들이 불연속이었다. 즉, Tsp이하에서 두 번째 Zeeman선의 자기장이 크게 증가했고 이중선의 사중극자 분열값(QS)과 이성질체 이동값(IS)도 증가했는데, 이를 Tsp에서 이중체 형성에 따른 이온들의 위치 이동 계산 결과와 비교하여 초교한 상호작용, 대칭성 및 공유 결합성 등의 변화와 관련시켜 해석하였다.