• Journal of the Korean Institute of Gas
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• v.13 no.2
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• pp.14-22
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• 2009

This article makes a comparative analysis on the productivity in gas distribution industry between Korea and Japan, using Malmquist productivity index(MPI). The estimated MPI during $1997{\sim}2005$ shows that the productivity of Korean gas distribution industry has been generally higher than that of Japanese gas distribution industry. But Korean MPI made a drastic change from positive improvement (+ 0.37) during $1997{\sim}2000$ to severe deterioration (-0.60) during $2001{\sim}2005$, while Japan MPI has seldom changed. This change of Korean MPI is analyzed to result from the worsening of technical change rather than technical efficiency change. According to this result, Korean gas distribution industry needs to improve the technical change.

• Journal of the Korean Society of Marine Environment & Safety
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• v.13 no.4
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• pp.79-85
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• 2007

Many countries foster the tour and leisure industries as a national strategic industry of the 21st century. The tour and leisure industry is expected to be reorganized from the land-based industry to the ocean-based industry as the GNP in a nation is over USD $20,000{\sim}30,000$ dollars. In Korea, since we adopt a five-day week, the total working hours for a week is shortened. As the result, leisure activities in family, such as experience tour, ecological tour, travel, and overnight tour, are expected to be increased. Leisure and sports tours, which link the tour and sports to rafting, hang gliding, and marine leisure, have been also increased over 21.6%. A number of small and big islands near Ho-Nam coastal areas play an important role as natural breakwater. Thus, the ports in Ho-Nam area is safely protected from physical effects by ocean waves and is maintained without constructing a breakwater. In this paper, we analyses the required conditions as the marine leisure base in the southwest sea area which has the natural advantages for marine leisure. We also discuss how to activate the yacht business on Ho-Nam coast area. And then we analyse the present situations and obstacles of a domestic marine leisure. We also suggest the plan to build up echo-marine leisure infrastructure for industrial growth of marine leisure in Ho-Nam area.

• Korean Journal of Optics and Photonics
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• v.23 no.4
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• pp.167-171
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• 2012

This paper reports on the stray light analysis results of a compact imaging spectrometer (COMIS) for a microsatellite STSAT-3. COMIS images Earth's surface and atmosphere with ground sampling distances of 27 m at the 18~62 spectral bands (0.4 ~ 1.05 ${\mu}m$) for the nadir looking at an altitude of 700 km. COMIS has an imaging telescope and an imaging spectrometer box into which three electronics PCBs are embedded. The telescope images a $27m{\times}28km$ area of Earth surface onto a slit of dimensions $11.8{\mu}m{\times}12.1mm$. This corresponds to a ground sampling distance of 27 m and a swath width of 28 km for nadir looking posture at an altitude of 700 km. Then the optics relays and disperses the slit image onto the detector thereby producing a monochrome image of the entrance slit formed on each row of detector elements. The spectrum of each point in the row is imaged along a detector column. The optical mounts and housing structures are designed in order to prevent stray light from arriving onto the image and so deteriorating the signal to noise ratio (SNR). The stray light analysis, performed by a non-sequential ray tracing software (LightTools) with three dimensional housing and lens modeling, confirms that the ghost and stray light arriving at the detector plane has the relative intensity of ${\sim}10^{-5}$ and furthermore it locates outside the concerned image size i.e. the field of view of the optics.

• Proceedings of the Mineralogical Society of Korea Conference
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• 2002.10a
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• pp.53-67
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• 2002

As in the past, we are concerned today with the magnitudes of mineral resources and the adequacy of these resources to meet future needs. In looking at global resource issues, we should consider the need for the resource, its supply, and the environmental consequences of using it. The need for a resource can become a resource dependency, especially as the global population expands and each of us becomes increasingly dependent upon hundreds of natural materials. Therefore, our great mineral consumption makes the human population a true 'Geologic Force', which will be even more significant in the future when the global population is projected to reach alarming proportions. Although our supplies of mineral resources probably will be sufficient for the 21s1 century, the uneven distribution of minerals in the Earth's crust almost certainly will continue to be a major problem The most likely result will be major shifts in both prices and sources of supply of many mineral resources. As for energy resources, we must avoid an obsessive dependency on one fuel and expand instead to thor energy resources. Finally, because the use of resources affects the environment, we need to focus on resource exploitation and global pollution, particularly in regard to ground water and arable land. We must manage our resources so as to be in balance with our environment. And the accelerated industrialization of South Korean economy over the last three decades has resulted in the mass consumption of nuneral commodities. South Korea has around 50 useful mineral commodities for the mineral industry, among 330 kinds of minerals described. The component ratio of the mining industry sector of the gross national production(GNP) in South Korea dropped from $1.2\%\;in\;1971\;to\;0.34\%$ in 1997 due to the rapid growth of other industries In the countxy. During the period from 1971 to 1997, the average growth rate of mineral consumption in South Korea was $9.13\%$ yearly and that of GNP per capita was $14.97\%$. The mineral consumptions per capita showed a continual Increase during the last 30 years as follows(parenthesis. GNP per capita): 0.99 metric tons in 1971($\$289$), 3.83 metric tons in 1989($\$5,210$), 6.11 metric tons in 1995 ($\$10,037$), and 6.66 metric tons in 1997($9,511). The total amount of mineral consumption in South Korea was 33 million tons of 32 mineral commodities in 1971, and 306 million metric tons of 47 mineral commodities In 1997.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.5 no.1
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• pp.13-20
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• 1985

Two Cable-Stayed bridge on south coast in Korea has not constructed until a quarter of a century past since the beginning of it's own era. Our country is about to be interested in such a type of bridge. It has succeeded in constructing the 500 m spanned bridge against wind and earthquake in other several countries. Many contries are striving for designning a long spanned bridge to 1000m. For the realization of such a long spanned bridge in Korea clues to the problems, "How to design it", should be solved one by one. One of difficulties is in analysing the mechanical system because of multi-orter indeterminacy. In this study one of the numerical methods is proposed in order to eliminate the troublesome.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.48 no.7
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• pp.10-16
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• 2011

We report on the simulation results of electrical/optical characteristics for nonpolar GaN LED having Mg-doped GaN spacer and quantum barrier, in comparison with those of the typical nonpolar GaN LED. In order to reduce the band-gap energy distortion and conduction-band discontinuity in InGaN/GaN multiple quantum wells(MQWs) of nonpolar GaN LED, and thereby to increase their current-voltage, light output power and emission peak intensity, we applied 6 nm-thick p-type($1{\times}10^{18}\;cm^{-3}$) GaN spacer and GaN QB schemes to the typical nonpolar GaN LED epitaxial structure. As a result, we found that the radiative recombination rate was increased by 23% in MQWs at 20 mA current injection. Also, the forward voltage($V_f$) and the light output power($P_{out}$) were improved by 3.7% and 7%, respectively, for the proposed nonpolar LED epitaxial structure, compared with those of the typical nonpolar GaN LED.

• Journal of the Microelectronics and Packaging Society
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• v.14 no.3
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• pp.7-13
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• 2007

In the optical module for optical communications, the flip chip bonding is used fer the precise alignment of the optical fiber and optical device. In flip chip bonding, the optical device is aligned and welded while observing the alignment mark of substrate and chip by using flip chip bonder in order to bond the optical device at the exact position. In this research, optical passive alignment method of photodiode(PD) flip chip bonding is suggested for low cost optical subassembly. By using the visible He-Ne laser (633nm wavelength), photodiode is easily aligned with emitting spot on the optical fiber with the help of stereoscopic alignment system. We compensated wavelength dependent deviation about 4m to find out real alignment position of 1550nm input laser by ray tracing. The maximum optical coupling efficiency between the optical fiber and photodiode was about 23.3%.

• Proceedings of the Korea Water Resources Association Conference
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• 2011.05a
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• pp.361-361
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• 2011

우리나라의 과거 기상자료 분석결과를 보면 최근 10년(1999~2008년)과 과거 30년(1971~2000년)의 자료를 비교하였을 때 연 평균 강수량과 기온이 각각 9.1%, 0.6$^{\circ}C$ 상승하였고 2010년 전 지구 기온은 $14.52^{\circ}C$로 20세기 평균인 $13.90^{\circ}C$보다 $0.62^{\circ}C$ 높아 기온 관측이 시작된 1880년 이래 최고를 기록하였으며(2005년과 공동 1위), 2010년 북반구 기온편차는 $0.73^{\circ}C$로 역대 기온 관측 사상 가장 높았고 남반구 또한 $0.61^{\circ}C$로 상위 6위에 위치되었다. 또한 우리나라에서는 겨울철 이상 저온 현상을 경험하기도 하였다. 이에 본 연구에서는 우리나라 전역 기상청 60개 지점 1980년 1월 1일부터 2009년 12월 31 일까지의 자료를 바탕으로 기록 일 최저 기온 및 기록 일 최고 기온의 발생빈도를 분석하고자 하였다. 확률이론에 따르면 동일한 분포를 갖는 확률변수의 독립적인 시계열의 경우 최대값 또는 최소값의 발생빈도는 ��/n의 비율로 감소하게 된다. 여기서 /n은 관측이 시작된 시점부터 해당 시점까지 자료의 수이다. 본 연구의 경우에는 특정 지점의 특정 시점에 관측된 일 최대 기온이 동일한 분포를 갖는 독립적인 시계열을 이룬다고 한다면(즉, 증가 또는 감소 추세가 있지 않다면), 어떤 해에 관측된 일 최고 기온이 그 동안에 특정 시점에 관측된 일 최고 기온들보다 높을 확률은 1/n이 될 것이다. 그러나 만약 일 최대(또는 최저) 기온의 기록경신 발생빈도가 감소 비율로부터 유의하게 이탈하게 된다면, 이는 일 최고(또는 최저) 기온의 분산이 커지거나 작아지는 현상이 벌어진 경우이거나 일 최고(또는 최저) 기온의 평균이 어떤 추세를 갖게 되는 경우가 될 것이다. 그 결과 기록 일 최저 기온 발생빈도에 대한 기록 일 최고 기온 발생빈도의 비는 현재 약 2.5정도의 값이 나오는 것으로 분석되었으며 이러한 결과는 1980년 이후로 기록 일 최고 기온의 발생빈도는 /n의 비율로 감소하지만 기록 일 최저 기온의 발생빈도는 /n의 비율보다 낮게 발생하기 때문인 것으로 파악되었다. 이러한 과거 자료의 분석을 통하여 지금까지 진행되어 오고 있는 기후변화의 패턴을 보다 명확하게 인식하고자 하였으며, 추후 다양한 기후수치실험으로부터 도출된 결과들의 신뢰성을 평가할 때 기초적인 비교 자료를 제공할 수 있을 것이다.

• Journal for History of Mathematics
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• v.21 no.4
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• pp.19-48
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• 2008

In this paper, the life of Emmy Noether is reviewed in context of today's society where progress in social and educational equality for women have not significantly impacted the participation of women mathematician at the highest level of mathematics study. Recent studies have shown that there is little or no gender difference in mathematics performance if the women are treated equally in the country. Yet, the number of women scientists/mathematicians at the university level or related research centers are very low for all countries including the U.S. as well as Korea. Emmy Noether became a mathematician in early 20th century Germany where women were discouraged(not allowed) from even studying mathematics at the University. She overcame gender, racial, and social prejudices of the time to become one of the greatest mathematicians of the 20th century as a founding contributor of Abstract Algebra. Overcoming all the difficulties to focus on the study of mathematics to contribute at the highest level of mathematics provides an example of leadership for both men and women that is relevant today. Especially for women, Emmy Noether's life is a study in perseverance for the love of mathematics that proves that there is no gender difference even at the highest level of mathematics.

• Proceedings of the KSEEG Conference
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• 2002.10a
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• pp.53-67
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• 2002

As in the past, we are concerned today with the magnitudes of mineral resources and the adequacy of these resources to meet future needs. In looking at global resource issues, we should consider the need for the resource, its supply, and the environmental consequences of using it. The need for a resource can become a resource dependency, specially as the global population expands and each of us becomes Increasingly dependent upon hundreds of natural materials. Therefore, our great mineral consumption makes the human population a true “Geologic Force”, which will be even more significant in the future when the global population is projected to reach alarming proportions. Although our supplies of mineral resources probably will be sufficient for the 21st century, the uneven distribution of minerals in the Earth's crust almost certainly will continue to be a major problem. The most likely result will be major shifts in both prices and sources of supply of many mineral resources. As for energy resources, we must avoid an obsessive dependency on one fuel and expand instead to other energy resources. Finally, because the use of resources affects the environment, we need to focus on resource exploitation and global pollution, particularly in regard to ground water and arable land. We must manage our resources so as to be in balance with our environment. And the accelerated industrialization of South Korean economy over the last three decades has resulted in the mass consumption of mineral commodities. South Korea has around 50 useful mineral commodities for the mineral industry, among 330 kinds of minerals described. The component ratio of the mining industry sector of the gross national production(GNP) in South Korea dropped from 1.2% in 1971 to 0.34% in 1997 due to the rapid growth of other industries in the country. During the period from 1971 to 1997, the average growth rate of mineral consumption in South Korea was 9.13% yearly and that of GMP per capita was 14.97%. The mineral consumptions per capita showed a continual increase during the last 30 years as follows(parenthesis: GW per capita); 0.99 metric tons in 1997($289), 3.83 metric tons in 1989($5, 210), 6.11 metric tons in 1995 ($10, 037), and 6.66 metric tons in 1997($9, 511). The total amount of mineral consumption in South Korea was 33 million tons of 32 mineral commodities in 1971, and 306 million metric tons of 47 mineral commodities in 1997.