• 대한산업공학회지
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• 제37권3호
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• pp.248-257
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• 2011

Cross docking is a logistics management concept in which items delivered to a terminal by inbound trucks are immediately sorted out, routed and loaded into outbound trucks for delivery to customers. Two main advantages by introducing a cross docking terminal are to consolidate multiple smaller shipment into full truck load and remove storage and order picking processes to save up logistics costs related to warehousing and transportation costs. This research considers the scheduling problem of trucks in the cross docking terminals with multi-door in an inbound and outbound dock, respectively. The trucks sequentially deal with the storage process at the one of inbound doors and the shipping process at the one of the outbound doors. A mathematical model for an optimal solution is derived, and genetic algorithms with two different chromosome representations are proposed. To verify performance of the GA algorithms, we compare the solutions of GAs with the optimal solutions and the best solution using randomly generated several examples.

• Journal of Chest Surgery
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• 제27권6호
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• pp.489-493
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• 1994

Our patient was a 2.3 kg, male of 33 weeks gestation and spontaneous vaginal delivery. Copious salivary secretion, mild aspiration pneumonia episode due to tracheoesophageal fistula and intermittent cyanotic appearance due to hypoxia were noted shortly after birth. Head up position, frequent upper pouch suction, and adequate fluid and antibiotic therapy were done in incubator. Combined Chest and abdominal film was revealed gas in the stomach and an haziness in right chest with mediastinal shift to the right side. Esophagogram revealed markedly dilated proximal esophagus as blind pouch, and Two dimensional echocardiography showed the Ventricular Septal Defect. The conclusion was congenital esophageal atresia with tracheoesophageal fistula, Vogt-Gross type C, Waterston Risk Category B. Surgical correction with Beardmore anastomosis was performed extrapleurally through 3rd rib bed after the cannulation of umbilical vein and preliminary gastrostomy. The fistula was closed by triple ligation and the upper pouch was then brought down to the presenting surface of the lower esophageal segment that incised, and end to side anastomosis was underwent using interrupt suture placed through the full thickness of both upper pouch and lower esophageal segment. The postoperative patient was well tolerated and recovered uneventfully, permitted feeding on 7th postoperative day after esophagogram.

• 한국분무공학회지
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• 제24권1호
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• pp.21-26
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• 2019

In Korea, Medium-duty trucks are classified into GVW (Gross Vehicle Weight) 3.5~10tons. MDTs are mostly used for logistics or delivery between regions. There have been studied on diesel fuel vehicles for SUVs(Sports Utility Vehicle) or light-duty trucks. But MDTs have been not studied. Therefore, this study have been used MDTs for characteristic exhaust emission. Test was carried out using the certification test mode (NEDC, New European Driving cycle) and the NIER mode in chassis dynamometer of the MDTs. And emission gas was analyzed for PN (Particulate Number), PN size distribution and aldehydes, VOCs (Volatile Organic Compounds), PAHs (Polycyclic Aromatic Hydrocarbons). This paper concluded that EURO-IV trucks produced more MSATs than EURO V trucks. Depending on the engine temperature, more MSATs were generated in cold temperature than in the hot start operation. However, the driving speed, the opposite results was obtained.

• Safety and Health at Work
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• 제14권1호
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• pp.10-16
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• 2023

Whilst Ecological momentary assessment (EMA) can provide important insights over time and across contexts among rotation workers whose work periods alternate with leave at home, it can also be challenging to implement in the resources and construction sectors. This review aimed to provide a summary of the methodological characteristics of EMA studies assessing health outcomes and related behaviors in rotation workers. Systematic searches in PubMed, Medline, EMBASE, CINAHL, PsycINFO, and Scopus were done to include 23 studies using EMA methods in assessing health-related outcomes and behaviors. EMA designs included daily diary: assessments once per day typically fixed at the end of day (47.8%), within day fixed interval time-based design: assessments on multiple times per day at certain times of day (17.4%) and combination of both designs (34.8%). Studies employed paper and pencil diaries (73.9%) and one or more electronic methods (60.9%): wrist-worn actigraphy device (52.2%) and online-based diaries (26.1%) for data collection. Most of the studies (91.3%) did not report prompting -EMAs by schedule alerts or compliance. Daily diary and within day fixed interval dairies designs are common, with the increasing use of electronic EMA delivery techniques. It is unclear how well participants adhere to assessment schedules, as these are inadequately reported. Researchers should report compliance-related information.

• 시스템엔지니어링학술지
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• 제20권spc1호
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• pp.65-75
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• 2024

As the demand for logistics services increases rapidly in modern society, the existing freight delivery system through road transportation is caused various problems such as traffic congestion and greenhouse gas emissions. To solve that, the development of an 'underground logistics tunnel-based cargo transportation system' is currently being considered in Korea. In order to build a new concept stable and safe logistics system, derive system design requirements and functional specifications, and reflect them at the development of target system. In this study, to make foundation for development of an "underground logistics tunnel-based cargo transportation system," define system components through analysis from a hierarchical perspective, and the functions of each component were analyzed and defined. We identified what interfaces the components have at each stage of the operating process. Lastly, we defined a detailed operation scenario based on the previously derived results, deriving target system functional requirements.

• 대한환경공학회지
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• 제34권1호
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• pp.7-15
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• 2012

Indicator PCB의 농도 수준은 2006년에 세계보건기구(WHO) 프로토콜에 따라 수집된 132개의 모유(초유, 출산 후 30일째 모유, 출산 후 60일째 모유)로 분석하였다. Indicator PCBs의 농도는 고분해능 가스크로마토그래피/고분해능 질량분석기를 이용한 동위원소희석법으로 측정되었으며, 이 방법은 국제적 경향을 비교 평가하기 위한 정확하고 정밀한 데이터를 제공한다. 또한, 모든 분석 결과를 토대로 평균일일섭취량(ADIs)이 계산되었다. 총 indicator PCBs의 중앙값은 14 ng/g lipid로, 다른 나라에서 검출된 농도보다 현저하게 낮았으며, PCBs 138, 153, 180은 분석한 지표 이성질체 합의 약 65%를 차지하였다. 가장 기여율이 높은 PCB 153은 총 indicator PCBs 농도와 매우 높은 상관관계를 나타내었다(p<0.001). PCBs 농도는 산모의 아이수가 증가할수록 확연히 감소하였고, 산모의 PCBs 축적과 배출에 있어 출산경력과 수유기간은 중요한 인자로 나타났다. 6개월 모유수유 기간 동안 총 indicator PCBs의 평균일일섭취량의 중앙값은 $0.077{\mu}g/kg{\cdot}bw/day$이었다. 초산부 모유 중 PCB 118의 농도는 1998년에 비해 25~35% 정도 감소하였으며, 이러한 경향은 지속될 것이라는 것을 보여준다.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2013년도 제44회 동계 정기학술대회 초록집
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• pp.183-184
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• 2013

Two main MBE growth techniques have been used: plasma-assisted MBE (PA-MBE), which utilizes a rf plasma to supply active nitrogen, and ammonia MBE, in which nitrogen is supplied by pyrolysis of NH3 on the sample surface during growth. PA-MBE is typically performed under metal-rich growth conditions, which results in the formation of gallium droplets on the sample surface and a narrow range of conditions for optimal growth. In contrast, high-quality GaN films can be grown by ammonia MBE under an excess nitrogen flux, which in principle should result in improved device uniformity due to the elimination of droplets and wider range of stable growth conditions. A drawback of ammonia MBE, on the other hand, is a serious memory effect of NH3 condensed on the cryo-panels and the vicinity of heaters, which ruins the control of critical growth stages, i.e. the native oxide desorption and the surface reconstruction, and the accurate control of V/III ratio, especially in the initial stage of seed layer growth. In this paper, we demonstrate that the reliable and reproducible growth of GaN on Si (110) substrates is successfully achieved by combining two MBE growth technologies using rf plasma and ammonia and setting a proper growth protocol. Samples were grown in a MBE system equipped with both a nitrogen rf plasma source (SVT) and an ammonia source. The ammonia gas purity was ＞99.9999% and further purified by using a getter filter. The custom-made injector designed to focus the ammonia flux onto the substrate was used for the gas delivery, while aluminum and gallium were provided via conventional effusion cells. The growth sequence to minimize the residual ammonia and subsequent memory effects is the following: (1) Native oxides are desorbed at $750^{\circ}C$ (Fig. (a) for [$1^-10$] and [001] azimuth) (2) 40 nm thick AlN is first grown using nitrogen rf plasma source at $900^{\circ}C$ nder the optimized condition to maintain the layer by layer growth of AlN buffer layer and slightly Al-rich condition. (Fig. (b)) (3) After switching to ammonia source, GaN growth is initiated with different V/III ratio and temperature conditions. A streaky RHEED pattern with an appearance of a weak ($2{\times}2$) reconstruction characteristic of Ga-polarity is observed all along the growth of subsequent GaN layer under optimized conditions. (Fig. (c)) The structural properties as well as dislocation densities as a function of growth conditions have been investigated using symmetrical and asymmetrical x-ray rocking curves. The electrical characteristics as a function of buffer and GaN layer growth conditions as well as the growth sequence will be also discussed. Figure: (a) RHEED pattern after oxide desorption (b) after 40 nm thick AlN growth using nitrogen rf plasma source and (c) after 600 nm thick GaN growth using ammonia source for (upper) [110] and (lower) [001] azimuth.

• Tuberculosis and Respiratory Diseases
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• 제69권6호
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• pp.418-425
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• 2010

Background: Little is known about the long-term effects of angiotensin-converting enzyme (ACE) treatment on post-tuberculosis emphysema. This study evaluated the effects of ACE inhibition on cardiac function and gas exchange in patients with post-tuberculosis emphysema. Methods: At baseline and at 6 months after initiation of ACE inhibition therapy, patients underwent pulmonary function testing, arterial blood gas analysis, and echocardiography, both at rest and post exercise. Cardiac output (CO) and right ventricular ejection fraction (RVEF) were measured at those time points as well. Results: After ACE inhibition; resting and post-exercise RVEF ($Mean{\pm}SEM,\;61.5{\pm}1.0,\;67.6{\pm}1.2%$, respectively) were higher than at baseline ($56.9{\pm}1.2,\;53.5{\pm}1.7%$). Resting and post-exercise CO ($6.37{\pm}0.24,\;8.27{\pm}0.34L/min$) were higher than at baseline ($5.42{\pm}0.22,\;6.72{\pm}0.24L/min$). Resting and post-exercise $PaO_2$ ($83.8{\pm}1.6,\;74.0{\pm}1.2mmHg$, respectively) were also higher than at baseline ($74.2{\pm}1.9,\;66.6{\pm}1.6mmHg$). Post-exercise $PaCO_2$($46.3{\pm}1.1mmHg$) was higher than at baseline ($44.9{\pm}1.1;\; Resting\;42.8{\pm}0.8\;vs.\;42.4{\pm}0.9mmHg$). Resting and post-exercise A-a $O_2$ gradient ($12.4{\pm}1.4,\;17.8{\pm}1.5 mmHg$) were lower than at baseline ($22.5{\pm}1.5,\;26.9{\pm}1.6mmHg$). Conclusion: In post-tuberculosis emphysema, RVEF and CO were augmented with a resultant increase in peripheral oxygen delivery after ACE inhibition. These findings suggest that an ACE inhibitor may have the potential to alleviate co-morbid cardiac conditions and benefit the patients with post-tuberculosis emphysema.

• 한국가스학회지
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• 제7권2호
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• pp.33-41
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• 2003

LPG는 사용, 저장, 생산 과정뿐만 아니라 이송 중에도 많은 잠재위험(Hazard)을 갖고있다. 소규모의 수요처일 경우, LPG 용기를 적재한 차량에 의해 지역 사업자에 의하여 배달된다. 만약 도심지역에 가스용기를 적재한 차량에 폭발사고가 발생한다면 주변지역에 재산 피해뿐 아니라 상당한 인명피해를 초래할 것이다 본 연구에서는 LPG 누출 사례연구를 통하여 가스용기를 이용한 LPG의 운반 중에 사고의 원인이 되는 잠재위험을 확인한 후 사고발생 시나리오를 작성하고 발생 가능성과 피해결과를 예측하는 위험성(risk)의 정량적 분석을 하였다. 본 연구에서는 위험분석 프로그램을 Excel과 Visual Basic으로 프로그래밍 하여, ETA(Event Tree Analysis)법으로 LPG 운반도중 발생할 수 있는 사고의 빈도수를 구한 뒤, 이를 바탕으로 폭발로 인한 피해 범위 및 피해정도를 도출하였다. UVCE의 경우, 가스용기에서 누출되어 증발된 LPG에 대하여 사고현장주변에서 10m 이내에서는 심각한 구조적 손상을 보이며, 150m 이상에서도 유리가 파열되는 심각한 손상확률을 보였다. 그리고 TNT 상당법으로 Probit 결과, 10분간 누출되었을 때 40m 지점에서 유리창의 $75\%$가 깨졌으며, 20m 지점에서 $16\%$, 40m 지점에서는 $10\%$의 구조적 손상을 보였다.

• 한국기후변화학회지
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• 제2권2호
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• pp.115-131
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• 2011

온실가스의 감축 규제가 세계 경제에 미치는 영향은 매우 클 것으로 예상되며, 산업 전반에 걸쳐 적절한 대응방안 도입이 필요한 시점이다. 이에 본 연구는 온실가스 감축 규제에 대응하기 위해서 취해질 수 있는 온실가스 저감 기술, 설비 개발, 에너지 절약 및 효율화 활동, 탄소배출권 구입을 통한 탄소 상쇄 등 여러 경제적 행위 중에서 탄소배출권 투자에 초점을 맞추어 연구하였다. 특히, 탄소배출권 투자 시 고려해야 할 위험 요인 중에서 UN 등록 거절 위험과 탄소배출권 가격변동성 위험을 최소화하기 위한 위험관리 모형을 설계하고 검증하였다. 이를 통해 탄소 상쇄가 필요한 다양한 분야의 이해관계자가 최적화된 탄소배출권과 관련한 전략을 수립할 수 있도록 제안하는 것을 목표로 한다. 기후변화에 따른 새로운 메커니즘에 국내 금융회사들이 신속히 대응할 수 있는 방법을 모색하고자 한 본 연구는 현재 청정개발체제(CDM)에서 발급되는 탄소배출권(CER)에 국한되지 않고 공동이행체제(JI) 프로젝트에서 발급되는 탄소배출권(ERU), 배출권거래제(ET)에서 인정되는 탄소배출권(AAU) 뿐만 아니라 향후 새롭게 인정될 탄소배출권에도 유사하게 적용될 수 있을 것이다.