• 한국항공우주학회지
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• 제37권2호
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• pp.156-165
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• 2009

우주발사체는 군용 미사일이나 과학로켓에 비해 크기가 크고 비행거리가 멀어 고장상황 발생 시 매우 위험하다. 따라서 비행시험 시 사고의 위험을 최소화시키기 위해 비행안전시스템의 운용이 필수적으로 요구된다. 이 때, 비행안전시스템에 적용되는 추적 필터는 일반적인 필터와는 달리 필터의 정확성보다는 안정성이 우선 시 된다. 본 논문에서는 전 비행 구간에 걸쳐 안정적으로 비행 정보를 획득하기 위해서 다중센서를 이용하여 융합필터를 구성하였다. 추정된 위치 및 순간낙하점 오차를 분석하여 구현된 융합필터의 성능을 분석하였다. 또한 각 센서에 연결된 부필터에 고장검출 알고리듬을 적용함으로써 비정상 상태일 경우 융합에서 제외하여 전체 필터의 신뢰성을 유지하게 됨을 검증하였다.

• Journal of Chest Surgery
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• 제18권4호
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• pp.718-731
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• 1985

Renal dysfunction is a common complication of open-heart surgery: a form of controlled hemorrhagic shock, and successful perioperative management of renal dysfunction depends on recognition of the risk factors and optimal management of factors influencing renal function, including cardiopulmonary bypass, and early detection of renal failure. Changes in renal functional parameters including Ccr, Cosm, CH2O, FENa, and RFI were observed prospectively in forty five patients operated on at Dept. of Thoracic and Cardiovascular Surgery, S.N.U.H., from April to June, 1985. They were 23 males and 22 females with 35 acquired and 10 congenital heart diseases and the mean age and body surface area of them were 38.010.3 years [22-63] and 1.5518 M2[1.151.92] respectively. Followings are the conclusion. 1. The Ccr, representative of renal function, is significantly improved from 90.231.3 ml/min/M2 preoperatively to 101.536.4 ml/min/M2 postoperative and day [P<0.05], and all patients were classified as postoperative renal functional class I of Abel, which representing adequate renal protection during our cardiopulmonary bypass. 2. The Cosm is significantly elevated at immediate postperfusion time and remained high at postoperative one day representing osmotic diuresis at that time, but CH2O shows no significant changes at immediate postperfusion period and is decreased significantly at postoperative one day, representing recovery of renal concentrating ability at that time with decreasing urine flow. 3. The absolute value and changing tendency in FENa and RFI during perioperative period shows no diagnostic reliability on these parameters, but those of CH2O appear to reveal future renal function more accurately than Ccr 4. The depth of hypothermia may be protective upon renal function against the ill effects of prolonged nonpulsatile cardiopulmonary bypass. 5. The depth of the hypothermia, pump time of more than 150 minutes, poor cardiac function, and intraoperative events such as embolism appear to be related with immediate postperfusion renal function. 6. Hemoglobinuria and hemolysis, poor preoperative renal function, history of cardiac surgery, and massive transfusion associated with bleeding appear not to be related with renal dysfunction.

• 에너지공학
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• 제28권3호
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• pp.10-17
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• 2019

국내 친환경 수소차 보급 정책에 따라 수소차와 수소충전소 인프라 개발에 대한 관련 업계의 연구는 활발하게 진행 중이다. 반면에 수소차와 수소충전소의 내구성 및 신뢰성에 직접적인 영향을 주는 기밀용 비금속 소재(라이너, 씰, 개스킷 등)의 위험성 평가 및 재료에 관한 실증 연구는 부족한 실정이다. 이에 본 연구에서는 FMEA를 활용하여 고압 수소 설비에 사용되는 비금속 부품의 라이너와 씰에 대한 위험요소를 도출한 후 심각도, 발생빈도, 검출도 등급을 점수로 환산하여 RPN값을 산정하였다. RPN의 최대값 600, 최소값 63, 평균값이 278.5로 산출되었으며, 라이너와 씰에 대한 주기적인 관리가 중요함을 확인하였다. 더불어 비금속 고무제품에 대한 수소침지와 산소노화시험을 통해 기초 자료로 활용 가능한 물리적 실험값을 제시하고자 하였다.

• 한국인터넷방송통신학회논문지
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• 제21권5호
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• pp.89-94
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• 2021

최근 제조업에서 경쟁력 향상을 위해 IIoT/ICT를 적용한 지능형 생산 공정을 많이 도입하고 있으며, 공기압출기에서 수집한 데이터를 이용한 예방 조치로 가용성 유지, 생산성 향상 및 관리비용을 최적화하는 시스템이 필요하다. 따라서, 본 연구에서는 전용 컨트롤 보드를 개발하고, 이를 원격으로 모니터링하기 위한 LoRa 통신 모듈을 적용하여 클라우드 서버에서 공기압축기에 대한 정보를 통합 수집 및 관리하였으며, 통합된 정보를 모든 운용자 및 관리자가 실시간으로 공통된 자료를 활용하도록 하였다. 이를 통해, M/S의 단계를 획기적으로 줄이고, 시스템 운용 가용성을 증대하였으며, 로컬 서버 운용 부담을 줄였다. 시스템 장애 상태를 공유함으로 유지보수 지연시간을 획기적으로 줄였으며, 유지보수 직원의 유선 및 모바일 활용으로 실시간 상태 감지를 제공, 비용과 공간적 문제를 획기적으로 개선하였다.

• Journal of Preventive Medicine and Public Health
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• 제54권3호
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• pp.190-198
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• 2021

Objectives: Insufficient evidence exists regarding factors that affect screening adherence among people with a family history of diabetes, who comprise roughly half of all patients with diabetes. Therefore, we aimed to identify the determinants of diabetes screening adherence in adults with a family history of diabetes who had not yet been diagnosed with diabetes. Methods: This cross-sectional study was conducted at selected urban primary healthcare facilities in Tehran, Iran. The study population was clinically non-diabetic adults above 20 years of age with a family history of diabetes in at least 1 first-degree relative. All eligible people identified on randomly-selected days of the month were invited to join the study. Results: Among 408 participants, 128 (31.4%) had received a fasting blood glucose check during the last year. Using binary logistic regression, the independent predictors of screening adherence were knowledge of adverse effects of diabetes such as sexual disorders (odds ratio [OR], 3.05) and renal failure (OR, 2.73), the impact of family members' advice on receiving diabetes screening (OR, 2.03), recommendation from a healthcare provider to have a fasting blood glucose check (OR, 2.61), and intention to have a fasting blood glucose check within the next 6 months (OR, 2.85). Other variables that predicted screening adherence were age (OR, 1.05), job (being a housekeeper; OR, 3.39), and having a college degree (OR, 3.55). Conclusions: Knowledge of the adverse effects of diabetes, physicians' and healthcare providers' advice about the benefits of early disease detection, and family members' advice were independent predictors of screening adherence.

• Journal of Ginseng Research
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• 제43권1호
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• pp.1-9
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• 2019

Background: Korean ginseng is an important cash crop in Asian countries. However, plant yield is reduced by pathogens. Among the Ilyonectria radicicola-species complex, I. mors-panacis is responsible for root-rot and replant failure of ginseng in Asia. The development of new methods to reveal the existence of the pathogen before cultivation is started is essential. Therefore, a quantitative real-time polymerase chain reaction method was developed to detect and quantify the pathogen in ginseng soils. Methods: In this study, a species-specific histone H3 primer set was developed for the quantification of I. mors-panacis. The primer set was used on DNA from other microbes to evaluate its sensitivity and selectivity for I. mors-panacis DNA. Sterilized soil samples artificially infected with the pathogen at different concentrations were used to evaluate the ability of the primer set to detect the pathogen population in the soil DNA. Finally, the pathogen was quantified in many natural soil samples. Results: The designed primer set was found to be sensitive and selective for I. mors-panacis DNA. In artificially infected sterilized soil samples, using quantitative real-time polymerase chain reaction the estimated amount of template was positively correlated with the pathogen concentration in soil samples ($R^2=0.95$), disease severity index ($R^2=0.99$), and colony-forming units ($R^2=0.87$). In natural soils, the pathogen was recorded in most fields producing bad yields at a range of $5.82{\pm}2.35pg/g$ to $892.34{\pm}103.70pg/g$ of soil. Conclusion: According to these results, the proposed primer set is applicable for estimating soil quality before ginseng cultivation. This will contribute to disease management and crop protection in the future.

• Perinatology
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• 제29권4호
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• pp.189-194
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• 2018

Congenital neuroblastoma is a rare disease. Placental metastasis is extremely rare and poor prognosis has been reported in neonates. Mirror syndrome could occur in mother with placental metastasis with possibilities of hypertension and edema. We report a case of detection of left suprarenal mass in fetus at $31^{+5}weeks^{\prime}$ gestation. Mother presented with palpitation, edema, headache, and hypertension. Maternal 24 hours urine vanillylmandelic acid (VMA) and normetanephrine (NME) level at 34 weeks' gestation were elevated. Consequently, emergent cesarean section was done. Based on abdominal ultrasonography and whole body magnetic resonance imaging, left adrenal tumor with liver metastasis was suspected. Neuroblastoma was confirmed by liver and placenta biopsy. Chemotherapy was started with Pediatric Oncology Group 9243 at day 7 and changed into Children's Oncology Group 3961 due to cholestasis and poor response during 2nd cycle. Plasma exchange was done for aggravated direct hyperbilirubinemia. The baby expired at 73 days due to multi-organ failure. Maternal symptoms were completely resolved in 2 weeks after delivery along with normalization of the elevated level of VMA and NME. We report a first case of mirror syndrome in Korean mother and fetus resulting from metastatic congenital neuroblastoma to placenta.

• Journal of Radiation Protection and Research
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• 제44권3호
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• pp.97-102
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• 2019

Background: Dose rate meters are the most widely used, and perhaps one of the most important tools for the measurement of ionising radiation. They are often the first, or only, device available to a user for an instant check of radiation dose at a certain location. Throughout the world, radiation safety practices rely strongly on the output of these dose rate meters. But how well do we know the quality of their output? Materials and Methods: This review is based on the measurements 1,158 commercially available dose rate meters of 116 different makes and models. Expected versus the displayed dose patterns and consistency was checked at various dose rates between $5{\mu}Gy{\cdot}h^{-1}$ and $2mGy{\cdot}h^{-1}$. Samples of these meters were then selected for further investigation and were exposed to radiation sources covering photon energies from 50 keV to 1.5 MeV. The effect of detector orientation on its reading was also investigated. Rather than focusing on the angular response distribution that is often reported by the manufacturer of the device, this study focussed on the design ergonomics i.e. the angles that the operator will realistically use to measure a dose rate. Results and Discussion: This review shows the scope and boundaries of the ionising radiation dose rate estimations that are made using commonly available meters. Observations showed both inter and intra make and model variations, occasional cases of instrument failure, instrument walk away, and erroneous response. Conclusion: The results indicate the significance of selecting and maintaining suitable monitors for specific applications in radiation safety.

• 융합신호처리학회논문지
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• 제21권3호
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• pp.121-126
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• 2020

소리 기반 기계 고장 진단은 기계의 음향 방출 신호에서 비정상적인 소리를 자동으로 감지하는 것이다. 수학적 모델을 사용하는 기존의 방법은 기계 시스템의 복잡성과 잡음과 같은 비선형 요인이 존재하기 때문에 기계 고장 진단이 어려웠다. 따라서 기계 고장 진단의 문제를 딥러닝 기반 이미지 분류 문제로 해결하고자 한다. 본 논문에서 스펙트로그램 이미지를 이용한 CNN 기반 자동화 기계 고장 진단 기법을 제안한다. 제안한 방법은 기계의 결함 시 발생하는 주파수상의 특징 벡터를 효과적으로 추출하기 위해 STFT를 사용하였으며, STFT에 의해 검출된 특징 벡터들은 스펙트로그램 이미지로 변환하여 CNN을 이용해 기계의 상태별로 분류한다. 그 결과는 제안한 방법은 효과적으로 결함을 탐지할 뿐만 아니라 소리 기반의 다양한 자동 진단 시스템에도 효과적으로 활용될 수 있다.

• 한국항공우주학회지
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• 제50권5호
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• pp.349-357
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• 2022

무인항공기의 비행조종컴퓨터는 비행 안전에 필수적인 장비로써 개발 단계에서부터 신뢰성과 안전성의 확보가 필수적이며, 고장 발생 시에도 정상적으로 기능을 수행할 수 있는 다중화 기반의 고장관리 설계가 요구된다. 무인기의 경우에는 비용, 무게, 전력소모 등을 감소하기 위하여 비행조종시스템의 이중화 설계를 고려하지만, 고장관리를 위한 고장 검출 및 분리 설계에 많은 제약이 있다. 본 논문에서는 무인기용 이중화 비행조종컴퓨터의 신뢰성을 향상시키기 위한 고장 검출 및 고장 분리를 위한 고장관리 설계 방안을 제안한다. 그리고 고장관리 설계를 적용해 개발한 비행조종컴퓨터는 통합시험환경에서 기능 시험을 수행하고 HILS 환경에서 고장 영향성 확인 시험을 수행한 후 무인기에 탑재하여 비행시험을 통해 그 신뢰성을 검증하였다.