• 교육시설 논문지
• /
• 제25권4호
• /
• pp.11-18
• /
• 2018

Global warming is happening now and inevitable. Everyone knows that immediate action should be taken to slow it down, but uncertain about the effective solution. Despite global efforts to reduce greenhouse gas emissions, sea levels are rising gradually. In 2013, Cornell University announced the Climate Action Plan(CAP) to make the campus greener, to reduce waste, and to ensure efficient use of resources. In particular, they set a goal of reducing energy use by 2050 and making carbon emissions to zero. Accordingly, the purpose of this study is to analyse the case of the master plan of Cornell Tech campus and its major buildings. Mainly, The House, faculty and student housing of Cornell Tech and the world tallest certified passive house, will be the main precedent that shows the architectural planning of passive house. Passive house technology, which was thought to be possible only in single-family houses, can be applied to high-rise buildings. If any passive house technology of The House project is actively introduced into the dormitory projects of domestic universities that are about to be built or renovated, it will be a good opportunity for the university to take the lead in preparing for global warming.

• 한국인구학
• /
• 제9권2호
• /
• pp.30-41
• /
• 1986

It is worthwhile to compare the major social indicators between Korea the and Taiwan particularly focusing on population because two countries share close similarities in many aspects and gave access to the advanced level among the developing countries in recent years. Similarities or dissimilarities presented in this paper will be helpful to the researchers and the policy makers of the two countries by giving them insight on the situation. The similarities and dissimilarities between the two countries in the field of demography and social indicators are summarized as follows : 1. Similarity indicators can be found in fertility. One of them is Net Reproduction Rate and it was less than one in both countries in 1985. The past trend of fertility, in fact level and pattern of it, of the two countries from 1960 to 1985 has been very similar. 2. Level and pattern of mortality is quite different between two countries. Mortality level of Taiwan is lower than that of Korea. 3. The close similarity between two countries was shown in population structure and aging index. 4. On future population projection, the population structure and the level and pattern of fertility of the two countries are very similar. During fourty years, the period from the current population growth rate which is a little more than 1% to the zero growth rate, the annual population growth rate of the two countries is approximately 0.6% and that is similar to those of the current industrialized countries. According to the medium variant of the projection, Korean population will reach Zero Growth Rate between 2020 and 2025 whereas Taiwan between 2025 and 2020 5. Current level of contraceptive prevalence of both countries is very similar showing above 70% of the eligible women in 1985 and one of the valuable factors of achieving this high rate within short period must be the national program of the family planning. A close cooperation in the field of population policy formulation and its implementation is indispensable because Korea and Taiwan have similarity in many population indicators.

• Nuclear Engineering and Technology
• /
• 제53권11호
• /
• pp.3790-3797
• /
• 2021

Although the individual channel readout method can improve the performance of PET detectors with pixelated photo-sensors, such as silicon photomultiplier (SiPM), this method leads to a significant increase in the number of readout channels. In this study, we proposed a novel multiplexing method that could effectively reduce the number of readout channels to reduce system complexity and development cost. The proposed multiplexing circuit was designed to generate bipolar pulses with different zero-crossing points by adjusting the time constant of the high-pass filter connected to each channel of a pixelated photo-sensor. The channel position of the detected gamma-ray was identified by estimating the width between the rising edge and the zero-crossing point of the bipolar pulse. In order to evaluate the performance of the proposed multiplexing circuit, four detector blocks, each consisting of a 4 × 4 array of 3 mm × 3 mm × 20 mm LYSO and a 4 × 4 SiPM array, were constructed. The average energy resolution was 13.2 ± 1.1% for all 64 crystal pixels and each pixel position was accurately identified. A coincidence timing resolution was 580 ± 12 ps. The experimental results indicated that the novel multiplexing method proposed in this study is able to effectively reduce the number of readout channels while maintaining accurate position identification with good energy and timing performance. In addition, it could be useful for the development of PET systems consisting of a large number of pixelated detectors.

• Nuclear Engineering and Technology
• /
• 제54권10호
• /
• pp.3587-3594
• /
• 2022

A distributed high-speed data acquisition and monitoring system for the RF negative ion source at Huazhong University of Science and Technology (HUST) is developed, which consists of data acquisition, data forwarding and data processing. Firstly, the data acquisition modules sample physical signals at high speed and upload the sampling data with corresponding absolute-time labels over UDP, which builds the time correlation among different signals. And a special data packet format is proposed for the data upload, which is convenient for packing or parsing a fixed-length packet, especially when the span of the time labels in a packet crosses an absolute second. The data forwarding modules then receive the UDP messages and distribute their data packets to the real-time display module and the data storage modules by PUB/SUB-pattern message queue of ZeroMQ. As for the data storage, a scheme combining the file server and MySQL database is adopted to increase the storage rate and facilitate the data query. The test results show that the loss rate of the data packets is within the range of 0-5% and the storage rate is higher than 20 Mbps, both acceptable for the HUST RF negative ion source.

• KDI Journal of Economic Policy
• /
• 제32권1호
• /
• pp.97-129
• /
• 2010

본고에서는 2002년 1월에서 2008년 12월까지 존재한 국내 주식형 펀드를 대상으로 하여 투자성과를 평가하고 마켓타이밍 능력의 존재 여부를 검토하였다. 주요 분석 결과는 다음과 같다. 첫째, 모든 투자비용을 공제한 순수익률 기준 펀드의 초과성과는 0과 다르지 않았다. 둘째, 투자비용이 공제되기 이전 총수익률 기준 펀드의 초과성과는 통계적으로 유의하게 0을 상회하였다. 특히, 보수수준과 초과성과 간에는 양의 상관관계가 있는 것으로 나타났다. 셋째, 보수수준이 높은 그룹에서 발견된 양의 초과성과를 마켓타이밍 능력과 주식선별능력으로 구분하는 추정을 실시하였으나, 추정 결과는 일의적인 해석이 곤란하였다. 분석 결과는 일단 Grossman and Stiglitz(1980)가 상정한 정보비용이 존재하는 효율적 시장가설과 일치한다. 그러나 보수가 높은 펀드의 초과성과 창출요인이 밝혀지지 않았으므로 이 해석의 타당성에 대한 결론적 언명은 추가 연구를 필요로 한다.

• 전기학회논문지
• /
• 제64권2호
• /
• pp.228-231
• /
• 2015

In power system research fields, one of current key issues is the construction and commercialization of micro grid site which is called green island, carbon zero island, energy independent island, building micro grid, etc. and various affiliated technologies have been being vigorously developed to realize. In addition, various researches about electric vehicles (EVs) are in progress and it is expected to penetrate rapidly with the next a few years. Some new load models should be developed integrating with electric vehicle loads because the EVs' deployment could cause the change of load composition rate on power system planning and operations. EVs are also resources for micro grid as well as distributed generation and demand response so that various supply and demand side resources should be considered for micro grid researches. In this paper, the load composition rate of residential sectors is prospected considering the deployment of EVs and the resource configuration of micro grid is optimized based on net present cost. In the optimization, the load patten of case studies includes EV's charging characteristics and various cases are simulated comparing micro grid environment and normal condition. HOMER is used to compare various cases and economic effects.

• 대한기계학회논문집B
• /
• 제35권4호
• /
• pp.399-407
• /
• 2011

고체산화물 연료전지(SOFC)와 가스터빈을 결합한 하이브리드 발전시스템에서 가스터빈의 규모별 성능차이가 시스템의 성능에 미치는 영향에 대하여 해석하였다. 이를 위해 kW급, MW 이하급, 수 MW급 등 서로 다른 세 가지 가스터빈을 선정하여 사용하였다. 가스터빈이 순 출력을 거의 내지 못하는 kW급 시스템에서도 연료전지 단독 시스템과 비교해 효율이 증가하였으며, 가스터빈의 출력이 커질수록 (즉, 성능이 좋아질수록) 하이브리드 시스템에서 가스터빈이 차지하는 비중이 커지고 시스템의 효율이 높아짐을 확인하였다. 가스터빈의 압력비 증가에 따른 성능 변화를 살펴본 결과 세 가지 하이브리드 시스템에서 모두 출력은 증가하지만, 효율의 변화는 크지 않음을 확인하였다.

• 한국산림과학회지
• /
• 제78권3호
• /
• pp.280-286
• /
• 1989

물푸레나무와 들메나무의 광합성(光合成)과 호흡(呼吸)의 특성(特性)을 밝히기 위하여 본 연구(硏究)에서는 묘포장(苗圃場)의 폿트에서 생육(生育)시킨 3년생묘목(年生苗木)에 대하여 광(光), 온도(溫度), 수분(水分)의 변화(變化)에 따른 광합성속도(光合成速度)와 호흡속도(呼吸速度)의 변화(變化), 그리고 그들의 계절변화(季節變化)를 측정비교(測定比較)하였다. 그 결과(結果)를 요약(要約)하면 다음과 같다. 1. 광보상점(光補償點)은 물푸레나무엽(葉)이 $35{\mu}Em^{-2}{\cdot}s^{-1}$, 들메나무엽(葉)이 $28{\mu}Em^{-2}{\cdot}s^{-1}$였다. 광포화점(光飽和點)은 두수종(樹種) 모두 $700{\mu}Em^{-2}{\cdot}s^{-1}$였다. 2. 최대광합성속도(最大光合成速度)는 물푸레나무엽(葉)이 $25^{\circ}C$. 들메나무엽(葉)이 $20^{\circ}C$ 정도에서 일어났다. 3 물푸레나무엽(葉)은 -13bar, 들메나무엽(葉)은 -10bar에서 순광합성속도(純光合成速度)의 초기감소(初期減少)가 시작되었고 물푸레나무엽(葉)은 -29bar, 들메나무엽(葉)은 -23bar 부터 순광합성속도(純光合成速度)가 0에 가까와 지기 시작했다. 4. 엽(葉)의 암호흡속도(暗呼吸速度)는 두수종(樹種) 모두 $10{\sim}40^{\circ}C$온도역(溫度域)에서 비슷한 값을 나타냈으며, -10bar의 수분결차(水分缺差)에서부터 증가(增加)하다가, -28bar 이하에서는 현저한 감소(減少)가 일어났다. 5. 엽(葉)의 순광합성속도(純光合成速度)는 6월(月)까지는 들메나무가 높았으나 이후는 물푸레나무가 높았다. 엽(葉)의 암호흡속도(暗呼吸速度)는 6~8월(月)에는 물푸레나무가 높았으나 그후는 비슷한 값을 나타냈다. 6. 줄기와 뿌리의 호흡속도(呼吸速度)는 두수종(樹種) 모두 4월(月)에 가장 높았으며 전생장계절(全生長季節)동안 물푸레나무가 들메나무 보다 높았다.

• The Journal of Asian Finance, Economics and Business
• /
• 제7권6호
• /
• pp.297-304
• /
• 2020

This paper applies the Data Envelopment Analysis (DEA) to compute the managerial efficiency of 30 insurance companies listed on the Saudi stock exchange for the duration of four years from 2015 to 2018. The companies taken as a sample of study included both conventional and Takaful insurance companies. The insurance sector of KSA is one of the largest sectors in the country, contributing a substantial percentage in the non-oil economy. Efficiency measurement and evaluation will provide a venue to introspect and benchmark frontiers to the sector. In the present study, we have utilized the basic Banker Charnes Cooper and Charnes Copper Rhodes models of DEA. Two inputs, namely, general & administrative expenses and policy & acquisition costs, and two outputs (Net premium earned and Investment Income & other incomes) were taken for efficiency calculations. The final outcomes of the study reveal that a good number of insurance companies operating in KSA are found to be efficient on managerial efficiency scale. Three firms remain the leader on the frontier of the managerial efficiency. And no company found with zero (0) efficiency or a negative efficiency. It is expected that the outcome of the study will provide benchmarks to managers and a road map to further improvement.

• 한국진공학회:학술대회논문집
• /
• 한국진공학회 2016년도 제50회 동계 정기학술대회 초록집
• /
• pp.390.1-390.1
• /
• 2016

The present work explains the interfacial energetics of all oxide transparent photodiodes. The optical, structural and morphological of copper oxides were systematically analyse by UV-Visible spectrometer, X-Ray diffraction, Raman spectroscopy, Scanning electron microscopy (SEM) and Atomic force microscopy measurements (AFM). The UV-Visible result exhibits optical bandgap of Cu2O and CuO as 2.2 and 2.05 eV respectively. SEM and AFM result shows a uniform grain size distribution in Cu2O and CuO thin films with the average grain size of 45 and 40 nm respectively. The results of Current-Voltage and Kelvin probe force microscope characteristics describe the electrical responses of the Cu2O/ZnO and CuO/ZnO heterojunctions photodiodes. The obtained electrical response depicts the approximately same knee voltages with a measurable difference in the absolute value of net terminal current. More over the present study realizes the all oxide transparent photodiode with zero bias photocurrent. The presented results lay the template for fabricating and analysing the self-bias all oxide transparent photodetector.