• 산업기술연구
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• 제24권B호
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• pp.59-64
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• 2004

GaAs thin films were grown epitaxially by MOCVD method on (001) GaAs substrate. And as a surfactant, Bi(bismuth) thin films were deposited on GaAs buffer layer by using TMBi(trimethylbismuth) source. In-situ reflectance difference spectroscopy(RDS) was used to monitor the surface reconstruction of GaAs and Bi thin films. As the results, under the exposure of TBAs(tertiarybuthylarsine) and hydrogen atmosphere, the surface reconstruction of GaAs was changed from As-rich c($4{\times}4$) to As-rich ($2{\times}4$), which was due to the adsoption and desorption of As dimers. The first bismuth surface related RDS signal was reported. At the deposition temperature of $450^{\circ}C$, Bi-terminated GaAs surface showed the RDS spectrum similar to that of Sb-terminated GaAs surface, possibly a ($2{\times}4$) surface. And Bi surface layers were rapidly evaporated with increasing the deposition temperature($550^{\circ}C$), finally becoming As-terminated ($2{\times}4$) surface.

• ETRI Journal
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• 제45권3호
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• pp.479-491
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• 2023

The automation of agricultural machines is an irreversible trend considering the demand for improved productivity and lack of labor in handling agricultural tasks. Unstructured working environments and weather often inhibit a seemingly simple task from being fully autonomously performed. In this context, we propose a remote driving system (RDS) to aid agricultural machines designed to operate autonomously. Particularly, we modify a commercial speed sprayer for orchard environments into a robotic speed sprayer to evaluate the proposed RDS's usability and test three sensor configurations in terms of human performance. Furthermore, we propose a confidence error ellipsebased task performance measure to evaluate human performance. In addition, we present field experimental results describing how the sensor configurations affect human performance. We find that a combination of a semiautonomous line tracking device and a wide-angle camera is the most effective for spraying. Finally, we discuss how to improve the proposed RDS in terms of usability and obtain a more accurate measure of human performance.

• Clinical and Experimental Pediatrics
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• 제46권11호
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• pp.1080-1084
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• 2003

목 적 : 저자들은 RDS 환아의 임상 경과 중에서 PDA가 동반되는 군과 동반되지 않은 군을 비교하여, 이들의 주산기 병력의 특성, 임상 양상과 경과를 비교 관찰하여 두 군 사이에 차이점이 있는지를 검토함으로서, 향후 RDS 환아의 관리에서 PDA 동반에 따른 효율적인 관리의 정보를 얻기 위하여 본 연구를 실시하였다. 방 법 : 2000년 1월부터 2002년 12월까지 경희대학교병원 신생아 집중치료실에서 신생아 RDS로 진단되어 치료한 총 83례를 대상으로 하였다. 총 83례 중에서 PDA를 동반한 군(A군)은 17례, PDA를 동반하지 않은 군(B군)은 66례였다. PDA는 울혈성 심부전의 임상증상을 보이거나, 청진상 심잡음이 들리며, 방사선 소견상에서 폐부종이 심해지거나 CT ratio가 증가되는 경우에 심초음파를 하여 진단하였다. 후향적 방법으로 증례들의 임상 기록지를 검토하여, 두 군 사이의 임상적 양상과 경과의 차이점을 분석하였다. 결 과: A군에서 B군에 비해 재태기간이 짧고 출생 체중이 낮아 미숙의 정도가 심할수록 PDA의 발생 빈도가 높았다. 주산기 가사의 빈도는 A군에서 의미있게 높았다. 만성 폐질환, 뇌실 내출혈, 괴사성 장염, 미숙아 망막증, 구루병, 패혈증, 담즙성 황달의 빈도가 B군에 비하여 A군에서 높았다. 결 론 : 두 군의 주산기 병력의 특성은 유의한 차이를 보임을 알 수 있었고 만성 폐질환 등의 합병증의 발생이 유의한 차이를 보였으나 후자의 경우 재태기간을 포함한 여러 인자를 고려하여야 하므로 앞으로 더 많은 연구가 이루어져야 한다고 사료된다.

• 한국방송∙미디어공학회:학술대회논문집
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• 한국방송공학회 1996년도 학술대회
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• pp.101-105
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• 1996

근래에 기존의 텔레비젼이나 라디오 방송에서 영상이나 음성의 방송 외에, 할당된 주파수를 최대한 효율적으로 사용하기 위한 부가방송의 개발이 활발히 이루어지고 있다. KBS에서는 오래 전부터 데이터 방송분야의 개발에 힘써왔으며 라디오에서는 RDS를 이용한 데이터 방송이 실용화 단계에 들어가고 있다. 1995년 하반기부터 KBS 제1라디오(표준FM)를 통하여 전국적으로 RDS 시험 방송을 하고 있으며, 또한 1997년에 문자정보 서비스를 위해 한국 실정에 맞는 새로운 RDS 한글 문자정보 규격을 만들어 서비스를 할 예정이다.

• Neonatal Medicine
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• 제18권2호
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• pp.409-411
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• 2011

In Korea, pulmonary surfactant (PS) replacement therapy in respiratory distress syndrome (RDS) was started in 1991 since when Surfacten$^{(R)}$ was imported from Japan. At the present time, Surfacten$^{(R)}$, Newfactan$^{(R)}$, Curosurf$^{(R)}$, and Infasurf$^{(R)}$ are available in Korea. The governmental health insurance covers the expense for multiple dose treatment since 2002 and the early prophylactic treatment (BW: <1,250 g or GP: <30 wks) since 2011. We undertook a multi-institutional collective study to evaluate the outcomes of PS over past 20 years in Korea (Period-I; 1990/91, P-II; 1996, P-III; 2002, and P-IV; 2007, P-V; 2010). There were 60 RDS neonates with PS treatment in P-I (16 hospitals), 1,179 in P-II (64), 1,595 in P-III (62), 1,921 in P-IV (57), and 3,160 in P-V (72). Decreased mortality rate, defined as the percentage of neonates who died within 28 days of birth, was seen between periods, P-V vs P-I, II, III, and IV (mortality rate: 10.1% vs. 40.0%, 30.0%, 18.7%, and 14.3%). We conclude that PS therapy contributed to improve remarkable outcome in RDS neonates over the last 20 years in Korea. However, more efforts should be made to optimize PS therapy for better outcome. Multiple PS doses for relapse and poor response, early prophylactic use, and better supportive care for pre-term infants are mandatory.

• Neonatal Medicine
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• 제25권3호
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• pp.109-117
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• 2018

Purpose: Minimally invasive surfactant therapy (MIST) is currently used as a method of surfactant replacement therapy (SRT) for the treatment of respiratory distress syndrome (RDS) in preterm infants with a gestational age of less than 30 weeks. However, few studies have been conducted on MIST in neonates with a gestational age of 30 weeks or more. In this study, we compared MIST with endotracheal intubation as a rescue SRT for spontaneously breathing neonates with a gestational age of 30 weeks or more who were diagnosed with RDS. Methods: We investigated the clinical characteristics of spontaneously breathing neonates admitted to the neonatal intensive care unit of the Inje University Sanggye Paik Hospital from January 1, 2014 to December 31, 2016. These neonates were born at a gestational age of 30 weeks or more and were diagnosed with RDS. The neonates who were administered surfactant by MIST were categorized into the MIST group (n=16) and those who underwent endotracheal intubation were categorized into the control group (n=45). Thereafter, the clinical characteristics between the groups were compared. Results: Compared to the control group, the MIST group was less likely to require mechanical ventilation within 72 hours (P<0.001). The frequency of bradycardia during SRT was also low in the MIST group (P=0.033). Conclusion: MIST is considered relatively feasible and safe for treating RDS for reducing the need for mechanical ventilation and decreasing the occurrence of bradycardia during surfactant administration in neonates with a gestational age of 30 weeks or more.

• 생명과학회지
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• 제9권2호
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• pp.201-206
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• 1999

본 연구는 정상 및 호흡곤란 신생아의 혈청내에 존재하는 nitric oxide(NO)의 생성을 관찰하고 erythropoietin (EPO)의 생성을 보기 위하여 정상 신생아 18명과 호흡곤란 신생아 16명으로부터 혈액을 채취하여 혈청내에서의 NO 및 EPO 생성량을 enzyme-linked immunosorbant assay법으로 측정하여 다음과 같은 결과를 얻었다. 1. 정상신생아의 혈청내 nitrite ion은 14.9$\pm$3.2 $\mu$M을 나타냈고 호흡곤란신생아군에서는 12.8$\pm$3.3 $\mu$M을 나타냄으로서 정상 대조군보다 호흡곤란군이 NO생성량이 낮음을 알 수 있었다. 2. 정상신생아의 혈청내 EPO는 16.2$\pm$3.4 mU/ml을 나타냈고 호흡곤란신생아군에서는 21.2 $\pm$5.4 mU/ml을 나타냄으로서 정상 대조군보다 호흡곤란군이 EPO생성량이 많음을 알 수 있었으며 통계학적으로 매우 유의한 차이를 나타냈다. 이상의 결과에서 호흡곤란증후군에서는 정상대조군에 비하여 NO생성이 대체적으로 저하되어 있음을 알 수 있었고 반대로 EPO의 생성은 증가되어 나타남으로서 EPO 상승에 따른 임상증상도 발현될 가능성이 있다하겠다.

• 한국통신학회논문지
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• 제28권3C호
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• pp.209-214
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• 2003

신뢰할 수 있는 DC-억압(DC-suppression) 방법으로 멀티모드 코딩 방법이 있다. 멀티모드 코드의 DC-억압 성능을 향상시키는 방법에는 스크램블러(scrambler)의 성능을 개선하는 방법과 후보 코드워드의 선택 기준(selection criteria)을 개선하는 방법이 있다. 후보 코드워드의 선택 기준으로 흔히 사용되는 MRDS(minimum running digital sum) 기준은 계산 및 구현이 쉬운 반면에 후보 코드워드의 길이가 길어질수록 성능이 저하되는 단점이 있다. 코드 워드 길이에 무관하게 최고의 성능을 갖는 MSW(mean squared weight) 기준은 구현상의 복잡도가 높다는 단점을 가진다. 본 논문에서는 이론상으로 가장 효율이 우수한 MSW의 성능에 근접하면서, 하드웨어 구현이 용이한 MPR DS(minimum peak RDS)와 ABSRDS(absolut RDS)라는 새로운 선택 기준을 제시하였고, 기존의 선택 기준과 함께 사용 시 보조적인 역할을 하여 성능 향상을 도모할 수 있는 SC(sign change) 알고리즘을 제시하였다.

• Perinatology
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• 제29권4호
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• pp.159-164
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• 2018

Objective: To compare neonatal respiratory morbidity of twins according to birth order related to gestational age and mode of delivery. Methods: We performed the retrospective research of the medical records of 3,224 neonates (1,612 twin pairs) born in a single center from January 2011 to December 2015. Subjects were classified into four gestational age groups: very (<32 weeks), moderate (32-33 weeks), late (34-36 weeks) preterm, and term (${\geq}37weeks$) groups. We investigated clinical characteristics and respiratory morbidity according to birth order related to gestational age group and mode of delivery. Results: We found increased risk of respiratory morbidity in second-born twin than first-born twin (P=0.039). Second-born twin was associated with increased risk of respiratory distress syndrome (RDS) in late preterm group (odds ratio [OR] 2.8, 95% confidence interval [CI] 1.30-5.95), and transient tachypnea of newborn in term group (OR 1.4, 95% CI 1.03-1.81). In vaginal delivery mode, there was no difference of respiratory morbidity between first and second-born twin in each group, but in cases of Cesarean delivery, second-born twin was related with a greater risk of RDS in late preterm group (OR 2.3, 95% CI 1.07-5.09). Birth order and Cesarean section independently increased the risk of RDS (adjusted OR [aOR] 1.69, 95% CI 1.12-2.54; aOR 2.14, 95% CI 1.25-3.66, respectively). Conclusion: Second-born twin and Cesarean delivery are associated with increased risk of RDS, especially in late preterm twins.

• Clinical and Experimental Pediatrics
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• 제65권4호
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• pp.188-193
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• 2022

Background: Respiratory distress syndrome (RDS) is a common cause of hospitalization and death in preterm infants who require surfactant treatment and respiratory support. Purpose: This study aimed to compare the clinical outcomes of minimally invasive surfactant therapy (MIST) and the INtubation, SURfactant administration, and Extubation (INSURE) technique in preterm infants with RDS. Methods: In this clinical trial, 112 preterm infants born at 28-36 weeks of gestation and diagnosed with RDS randomly received 200-mg/kg surfactant by MIST or the INSURE method. In the MIST group, surfactant was administered using a thin catheter (5F feeding tube); in the INSURE group, surfactant was administered after intubation using a feeding tube and the tracheal tube was removed after positive pressure ventilation was started. Nasal continuous positive airway pressure was applied in both groups for respiratory support and the postprocedure clinical outcomes were compared. Results: The mean hospitalization time was shorter for infants in the MIST group than for those in the INSURE group (9.19±1.72 days vs. 10.21±2.15 days, P=0.006). Patent ductus arteriosus was less frequent in the MIST group (14.3% vs. 30.4%, P=0.041). Desaturation during surfactant administration occurred less commonly in the MIST group (19.6% vs. 39.3%, P=0.023). There were no significant intergroup differences in other early or late complications. Conclusion: These results suggest that surfactant administration using MIST could be a good replacement for INSURE in preterm infants with RDS since its use reduced the hospitalization time and the number of side effects.