• 수산해양교육연구
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• 제16권2호
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• pp.181-186
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• 2004

The current situation of heating and cooling system of the classrooms of our country is rather poor compared not only to those of the developed nation's classrooms but also in case of other buildings such as financial institutions, office compounds. In winter, especially students have been in hatred state with respect to their health due to the fact that the heater is operated by petroleum. Korea has been heavily dependent on foreign nations for the very fact of importing energy in the form of oil or natural gas. So it is important to conserve energy and the picture with respect to energy remains similar till today as it was in long past periods. The purpose of this study is to contribute actively in energy economy and facilitate towards a healthy school life of students and other institutions proving a system of extracting energy from river water and then converting it into heat which can stand as an effective alternate of expensive oil or gas. Installing oil-stove based heating system at classrooms of school could get considerable attentation in several respects. The proposed heat energy could be collected unlimitedly both in time and in amount. The stable and uninterrupted heat energy from river water, optimally utilizing the typical-regional and geographical characteristics has the potential to be long-lasting in duration, cheap in energy economy and beneficial to health as well.

• Current Optics and Photonics
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• 제2권2호
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• pp.195-202
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• 2018

A Scanning Rayleigh Doppler lidar for wind profiling based on a non-polarized beam splitter cube optically contacted FPI is developed for wind measurement from high troposphere to low stratosphere in 5-35 km. Non-polarized beam splitter cube optically contacted to the FPI are used for a stable optical receiver. Zero Doppler shift correction is used to correct for laser or FPI frequency jitter and drift and the timing sequence is designed. Stability of the receiver for Doppler shift discrimination is validated by measuring the transmissions of FPI in different days and analyzed the response functions. The maximal relative wind deviation due to the stability of the optical receiver is about 4.1% and the standard deviation of wind velocity is 1.6% due to the stability. Wind measurement comparison experiments were carried out in Jiuquan ($39.741^{\circ}N$, $98.495^{\circ}E$), Gansu province of China in 2015, showing good agreement with radiosonde result data. Continuous wind field observation was performed from October 16th to November 12th and semi-continuous wind field of 19 nights are presented.

• Archives of Pharmacal Research
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• 제20권6호
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• pp.560-565
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• 1997

The physicochemical properties of melatonin (MT) in propylene glycol (PG) and 2-hydroxypropyl-.betha.-cyclodextrin $(2-HP{\beta}CD)$ vehicles were characterized. MT was endothermally decomposed as determined by differential scanning calorimetry (DSC). Melting point and heat of fusion obtained were $116.9{\pm}0.24^{\circ}C $.and $7249{\pm}217 cal/mol$., respectively. MT as received from a manufacture was very pure, at least 99.9%. The solubility of MT in PG solution increased slowly until reaching 40% PG and then steeply increased. Solubility of MT increased linearly as concentration of $2-HP{\beta}CD$ without PG INCREASED$(R^2=0.993)$. MT solubility in the mixtures of pg and $2-HP{\beta}CD$ also increased linearly but was less than the sum of its solubility in $2-HP{\beta}CD$ and PG individually. The MT solubility was low in water, simulated gastric or intestinal fluid but the highest in the mixture of PG(40v/v%) and $2-HP{\beta}CD$ (30w/v%) although efficiency of MT solubilization in $2-HP{\beta}CD$ decreased as the concentration of PG increased. MT was degraded in a fashion of the first order kinetics $(r^2>0.90)$. MT was unstable in strong acidic solution (HCl-NaCl buffer, pH 1.4) but relatively stable in other pH values of 4-10 at $70^{\circ}C$. In HCl-NaCl buffer, MT in 10% PG was more quickly degraded and then slowed dpwm at a higher concentration. However, the degradation rate constant of MT in 2-HP.betha.CD was not changed significantly when compared to the water. The current studies can be applied to the dosage formulations for the purpose of enhancing percutaneous absorption or bioavailability of MT.

• Earthquakes and Structures
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• 제13권2호
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• pp.151-164
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• 2017

This article aims to investigate the possible retrofitting of a deficient building with soft story failure mode by connecting it to an adjacent building which is designed based on current code with friction dampers at all floors. Low cost and high performance reliability along with significant energy dissipation pertaining to stable hysteretic loops may be considered in order to choose the proper damper for connecting adjacent buildings. After connecting two neighbouring floors by friction dampers, the sliding forces of dampers at various stories are set in two arrangements: uniform sliding force and then variable sliding force. In order to account for the stochastic nature of the seismic events, incremental dynamic analyses are employed prior and after the installation of the friction dampers at the various floors. Based on these results, fragility curves and mean annual rate of exceedance of serviceability and ultimate limit states are obtained. The results of this study show that the collapse mode of the deficient building can affect the optimum arrangement of sliding forces of friction dampers at Collapse Prevention (CP) performance level. In particular, the Immediate Occupancy (IO) performance level is not tangible to the sliding force arrangement and it depends solely on sliding force value. Generally it can be claimed that this rehabilitation scheme can turn the challenge of pounding two adjacent buildings into the opportunity of dissipating a large amount of the seismic input energy by the friction dampers, thus improving significantly the poor seismic performance of the deficient structure.

• 상하수도학회지
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• 제35권5호
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• pp.335-349
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• 2021

As the frequency of seismic disasters in Korea has increased rapidly since 2016, interest in systematic maintenance and crisis response technologies for structures has been increasing. A data-based leading management system of Lifeline facilities is important for rapid disaster response. In particular, the water supply network, one of the major Lifeline facilities, must be operated by a systematic maintenance and emergency response system for stable water supply. As one of the methods for this, the importance of the structural health monitoring(SHM) technology has emerged as the recent continuous development of sensor and signal processing technology. Among the various types of SHM, because all machines generate vibration, research and application on the efficiency of a vibration-based SHM are expanding. This paper reviews a vibration-based pipeline SHM system for seismic disaster response of water supply pipelines including types of vibration sensors, the current status of vibration signal processing technology and domestic major research on structural pipeline health monitoring, additionally with application plan for existing pipeline operation system.

• 한국정보통신학회논문지
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• 제25권9호
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• pp.1166-1175
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• 2021

국내 스마트시티와 긴급차량 우선신호 제어시스템의 현재 상황과 발전동향을 알아보고, 긴급차량 우선신호 제어시스템의 기존 효과분석과 신호제어시스템의 보안을 위한 국내외 선행 연구 내용을 바탕으로, 긴급차량 우선신호 제어시스템을 구축하고 긴급차량에 실제 적용 및 시험운행을 통해 시간단축의 효과성을 분석하였다. 더불어 실시간 신호시스템 제어의 보안관리 및 안정적인 서비스를 위해 기존 ISMS-P 인증제도와 한국인터넷진흥원 사이버보안 가이드의 보안요구사항과 보안위협 항목에 따른 보안대책의 연관성에 따라 비교하여 맵핑함으로서, 인명구조나 화재 등 긴급상황 발생 시 시민의 소중한 생명과 재산을 지킬 수 있는 골든타임 확보 가능성을 높일 수 있도록 ISMS-P 인증제도의 기술적 통제항목 개선을 제안한다.

• 한국항해항만학회지
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• 제45권3호
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• pp.87-94
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• 2021

국제해사기구의 연료유 황 함유량 제한 등, 세계적으로 강화되고 있는 환경규제로 LNG를 선박 연료로 사용하는 연구 및 사업이 활발히 진행되고 있다. 본 연구에서는 기본설계 되어 있는 부유식 벙커링 터미널(FLBT, Floating LNG bunkering terminal)을 대상으로, STS LNG 하역 작업을 위해 접안 하는 과정을 수치 시뮬레이션으로 평가하였다. 수치해석에서는 예인선이 대상선박을 밀 경우 이를 가상의 펜더로 가정하였으며, 당길 때는 HMPE 로프 특성을 적용하였다. 해석에는 파랑, 조류, 바람 1년 재현 확률의 해상조건을 적용하였다. 수치모델은 선행 모형시험 결과로부터 조정되어 정확한 결과를 얻을 수 있도록 하였다. 해석 결과 LNG선은 대부분의 1년 환경조건에서 안전한 접안이 가능하였다. 파랑 방향에 따라 안정성의 차이가 큼으로 FLBT의 Heading control 기능을 적용하여 횡파를 피한다면 더욱 안정적인 운용이 가능할 것이다.

• 자원ㆍ환경경제연구
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• 제28권2호
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• pp.177-200
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• 2019

전력수급계획의 근간이 되는 전력수요 전망은 GDP와 기상변수 등 다양한 요인에 의해 영향을 받기 때문에 확률 프로세스로 이해할 수 있다. 이 전망치를 바탕으로 전력설비의 구성 방안이 수립되는데, 실제 의사결정 과정은 주어진 확률분포에 대한 정보가 온전하다고 가정한다는 한계를 가진다. 그러나 현실적으로는 확률분포 자체의 중첩 불확실성이 존재하기 때문에 강건한 최적계획(robust optimization)의 수립이 필요하다. 본 논문은 중첩 불확실성을 포함한 발전설비 조정의 최적의사결정을 연구한다. 구체적으로 원자력의 감축투자 관련 실물옵션 모형을 수립하고 우리나라 전력수급기본계획의 특성을 고려한 중첩 불확실성하에서 원전감축 투자를 분석한다. 분석 결과, 현재의 원전축소 정책은 전력수요 증가율이 낮다는 것을 전제로 한 정책으로서 전력수요 증가에 대응할 수 있는 정책 강건성을 갖추지는 못한다는 것을 보여준다.

• 대한간호학회지
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• 제49권1호
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• pp.104-112
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• 2019

Purpose: This study aimed to identify types of quality of life (QoL) based on the 5 dimensions of EQ-5D and predict factors affecting types of QoL. Methods: This study was a secondary analysis using data from the Korean Health Panel Survey-II(2012). Participants were 2,071 middle-aged men who had completed the additional survey in 2012 and the data were analyzed using SPSS 20.0 and Mplus 5.21 for latent analysis. Results: Three latent classes of QoL were identified: serious (2.4% of the sample), threatened (15.5%), and stable types (82.0%). The types and characteristics of QoL among the latent classes differed. On comparing latent type 1 with latent type 2, the socioeconomic status (p<.05), employment status (p<.05), and subjective health status (p<.001) were found to be significant. On comparing latent type 1 with latent type 3, the socioeconomic status (p<.05), current smoking status (p<.001), and subjective health status (p<.001) were found to be significant. On comparing latent type 2 with latent type 3, the socioeconomic status (p<.05), subjective health status (p<.001), stress (p<.001) were found to be significant. Conclusion: The results showed significant heterogeneity in types of QoL and the predictors of QoL by types were different. These findings provide basic information for developing nursing interventions to improve QoL. Specific characteristics depending on the subtypes should be considered during the development of interventions.

• 자원리싸이클링
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• 제28권1호
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• pp.3-14
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• 2019

구리는 뛰어난 전기전도성 및 열전달 특성으로 인해 많은 전자기기 및 건축 부품에 활용되고 있고 니켈 등 다른 도금의 밑 도금으로 사용되는 등 현대 산업에서 필수적으로 사용되는 소재이다. 뿐만 아니라 차세대 산업군에서 배선, 센서, 데이터 장비의 사용량과 중요도가 더욱 커지면서 그 활용도가 더욱 커질 것으로 예상됨에도 불구하고 유럽발 경제위기, 중국 경제 저성장 기조, 트럼프 대통령의 공공 산업설비 투자 공약 등에 따라 가격이 급동하는 추세를 보여 안정적인 수급 확보 및 자원관리에 어려움을 겪는 실정이다. 국내 구리 사용량의 거의 대부분을 전기동을 이용하여 사용하기 때문에 본 연구에서는 상용화 되고 있는 구리 재활용 기술과 연구 단계에 머물고 있는 구리 재활용 기술을 구분하여 각각의 기술적 수준을 파악하였다. 이를 통해 각 공정별 특징과 향후 기술개발이 요구되는 분야를 고찰해 보고자 하였다.