• Journal of Astronomy and Space Sciences
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• 제22권4호
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• pp.419-430
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• 2005

We have carried out a statistical analysis on solar wind dynamic pressure pulses during geomagnetic storms. The Dst index was used to identify 111 geomagnetic storms that occurred in the time interval from 1997 through 2001. We have selected only the events having the minimum Dst value less than -50 nT. In order to identify the pressure impact precisely, we have used the horizontal component data of the magnetic field H (northward) at low latitudes as well as the solar wind pressure data themselves. Our analysis leads to the following results: (1) The enhancement of H due to a pressure pulse tends to be proportional to the magnitude of minimum Dst value; (2) The occurrence frequency of pressure pulses also increases with storm intensity. (3) For about $30\%$ of our storms, the occurrence frequency of pressure pulses is greater than $0.4\#/hr$, implying that to. those storms the pressure pulses occur more frequently than do periodic substorms with an average substorm duration of 2.5 hrs. In order to understand the origin of these pressure pulses, we have first examined responsible storm drivers. It turns out that $65\%$ of the studied storms we driven by coronal mass ejections (CMEs) while others are associated with corotating interaction regions $(6.3\%)$ or Type II bursts $(7.2\%)$. Out of the storms that are driven by CMEs, over $70\%$ show that the main phase interval overlaps with the sheath, namely, the region between CME body and the shock, and with the leading region of a CME. This suggests that the origin of the frequent pressure pulses is often due to density fluctuations in the sheath region and the leading edge of the CME body.

• Communications of Mathematical Education
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• 제28권1호
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• pp.1-17
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• 2014

Recently a student's mathematical thinking and problem-solving skills are emphasized. Nevertheless, the students solved the problem associated with a given type of problem solving using mechanical algorithms. With this algorithm, It's hard to achieve the goal that are recently emphasized. Furthermore It may be formed error or misconception. However, consistent errors have positive aspects to identify of the current cognitive state of the learner and to provide information about the cause of the error. Thus, this study tried to analyze the error happening in the process of solving gearwheel-involved problem and to propose the correct teaching method. The result of student's error analysis, the student tends to solve the gear-wheel problem with proportional expression only. And the student did not check for the proportional expression whether they are right or wrong. This may be occurred by textbook and curriculum which suggests only best possible conditioned problems. This paper close with implications on the discussion and revision of the concepts presented in the curriculum and sequence related to the gearwheel-involved problem as well as methodological suggested of textbook.

• The Korean Journal of Financial Studies
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• 제6권1호
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• pp.23-45
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• 2000

기존연구에 의하면 무상증자의 공시는 공시기간 중 정(+)의 가격효과를 초래하는 것으로 나타나고 있다. 무상증자에 대한 이러한 시장의 호의적인 반응을 설명하기 위해 여러 가설이 제기되어 왔으며, 그 중 무상증자는 좋은 내부정보를 외부에 신빙성 있게 전달하는 신호기제가 될 수 있다는 신호가설이 특히 지지를 받고 있다. 그런데 짧은 공시기간 중의 정(+)의 주가반응만을 보고 신호가설이 지지된다고 단정짓는데는 무리가 있다. 본 연구에서는 과연 신호가설이 주장하는 것처럼 무상증자가 사업기회의 확대, 미래현금흐름의 증대, 추후 차입여력의 증대를 가져오는가를 더 면밀히 검증하기 위하여 무상증자 실시기업의 장기성과를 조사하였다. 본 연구의 특징은 (1)공시기간 이후의 1년 이내의 기간에 중점을 둔 대부분의 기존연구와 달리 증자 후 36개월간의 장기성과를 측정하였으며, (2)주가수익률 자료와 회계자료를 동시에 이용하여 장기성과를 조사하였고, (3)장기 초과수익률 측정과 검증에 있어 통계적 오류가 있는 누적초과수익률(CAR)을 보완하기 위해 매입보유초과수익률(BHAR)을 사용했으며, 이를 위해 엄격한 기준을 적용하여 표본기업과 비교기업을 선정하였다는 데 있다. 실증분석 결과 신호가설을 지지하는 증거는 발견하지 못하였으며 오히려 무상증자 실시기업이 시장평균 또는 비교기업인 비증자기업에 비해 장기적으로 주가수익률 및 영업성과에 있어 저성과를 보이는 증거를 상당 수 발견하였다. 구체적으로 동일가중평균수익률로 조정한 보유기간 초과수익률의 경우 증자 후 1개월에서 24개윌까지의 BHAR이 5% 미만 수준에서 부(-)의 값을 보였으며, 비모수통계치를 사용할 경우 $1{\sim}36$개월까지의 전기간에서 유의한 부(-)의 저성과를 보이고 있다. 또한 영업성과면에서도 증자기업이 비증자기업에 비해 증자 후 수익성과 현금흐름이 저조하게 나타나고 있다.해 현물시장의 수익률, 변동성이 높은 것으로 나타났으나, 변경후에는 현물시장에 비해 선물시장의 수익률 변동성이 높은 것으로 나타났다. VAR 분석에 의하면 변경후가 변경전에 비하여 선물이 현물을 선도하는 시차가 다소 커진 것으로 나타나 현물시장과 선물시장이 동시에 가격제한폭 확대후에 비효율적으로 되었다는 의미로 판단된다.기간에서는 선물의 15분 선도효과와 현물의 1분 선도효과가 발견되어 선물의 선도효과가 지배적임을 발견하였다.적 일정하게 하는 소비행동을 목표로 삼고 소비와 투자에 대한 의사결정을 내리고 있음이 실증분석을 통하여 밝혀졌다. 투자자들은 무위험 자산과 위험성 자산을 동시에 고려하여 포트폴리오를 구성하는 투자활동을 행동에 옮기고 있다.서, Loser포트폴리오를 매수보유하는 반전거래전략이 Winner포트폴리오를 매수보유하는 계속거래전략보다 적합한 전략임을 알 수 있었다. 다섯째, Loser포트폴리오와 Winner포트폴리오를 각각 투자대상종목으로써 매수보유한 반전거래전략과 계속거래 전략에 대한 유용성을 비교검증한 Loser포트폴리오와 Winner포트폴리오 각각의 1개월 평균초과수익률에 의하면, 반전거래전략의 Loser포트폴리오가 계속거래전략의 Winner포트폴리오보다 약 5배정도의 높은 1개월 평균초과수익률을 실현하였고, 반전거래전략의 유용성을 충분히 발휘하기 위하여 장단기의 투자기간을 설정할 경우에 6개월에서 36개월로 이동함에 따라 6개월부터 24개월까지는 초과수익률이 상승하지만, 이후로는 감소하므로, 반전거래전략을 활용하는 경우 주식투자기간은 24개월이하의 중단기가 적합함을 발견하였다. 이상의 행태적 측면과 투자성과측면의 실증결과를 통하여 한국주식시장에 있어서 시장수익률을 평균적으로 초과할 수 있는 거래전략은 존재하므로 이러한 전략을 개발 및 활용할 수 있으며, 특히, 한국주식시장에 적합한 거래전략은 반전거래전략이고, 이 전략의 유용성은

• Journal of the Korea Academia-Industrial cooperation Society
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• 제14권2호
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• pp.655-664
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• 2013

This study aims to identify forecasting factors of baby boomer's social participation desire. For this purpose, I utilized Hyun-Jung Kang(2012)'s data whose 1,115 sample were collected based on residential area and gender. The major findings are as follows; First, 77.7% of baby boomers are actually participating in economic activities. 27.0% in volunteering activities and 79.3% in leisure activities. 80.9% of baby boomers have intention to participate in economic activities after retirement, 76.7% in volunteering activities after retirement and 82.2% in leisure activities after retirement. Second, looking at the relationship between current social activity participation and intention to participate after retirement, those who are currently having social activities turn out to have higher intention to participate social activities after retirement. Those who wish to participate in social activities, although they don't participate in social activities currently, turn out to be 55.8% for economic activities, 70.6% for volunteering activities and 66.5% for leisure activities. Third, whether they are currently participating in social activities turns out to be most compelling forecasting factor for the desire on social participation after retirement. These results were discussed in terms of the continuity theory. and proposed that you need from the preparation of Middle - aged to activate the participation of important social variables known as old age life satisfaction.

• Journal of the Korean association of regional geographers
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• 제12권1호
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• pp.44-58
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• 2006

This study of Shintoism is to inquire the relationships between social-political ideology and place of Shinto shrine(神社). In Korea, the Shinto shrine was a place of the center of Japanese colonial policy that symbolized the goal of Japanese Imperialism. This was one of the strategies of "Japan and Korea Are One". Before the China and Japan War in 1937, the number of shrines amounted to 51 sites, 12 of them were closely related to open ports, and the others were located at inland major cities. They also were associated with railroad transportation systems that tied coast and inland major cities. This spatial distribution of shrines was so called "Shrine Network" that was essential in tracing Japanese invasion into Korea. It was an imperial place where Japanese residence and colonial landscape were combined together to show the strength of Japanese Imperialism. Most of shrines were located at a hill with a view on the slope of a mountain and honored Goddess Amaterasu and the Meiji Emperor. I presume from these facts that Shinto Shrine was a supervisionary organization for strategic purpose. The Jeonju Shrine was located on a small hill, Dagasan(65m) where commanded a splendid view of Jeonju city and honored Goddess Amaterasu and the Meiji Emperor. It was a place which was adjacent to Japanese residence and colonial landscape. The Dagasan was changed as a symbolic site for Japanese Imperialism. But, after liberation in 1945, the social-political symbol of the hill was changed. By the strong will of civil, there was a monument to the loyal dead and the national poet, Yi Byeng-gi placed for national identity at the site of the demolished Jeonju Shrine. Dagasan as a place of national identity, shows the symbolic decolonization and the changing ideology. After all, this shows that political ideology is represented in a place with landscape.

• KOMUNHWA
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• 60호
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• pp.27-64
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• 2002

It has been known that pit-wooden chamber tomb with stone piling, pit-wooden chamber tomb, jar coffin tomb and fosse-girded tomb were the chief burial systems of the 'Jumtodae' pottery cultural age in Honam province. But in this thesis, I lay emphasis on

• Spatial Information Research
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• 제16권4호
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• pp.489-497
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• 2008

Currently, GIS has been widely used in the hedonic analyses of urban apartment housing markets in Korea. In those analyses, the apartment complexes are typically represented as the points or the polygons on the GIS maps and the location variables of the analyses are measured based on the points or the polygons. In this study, the relative performance of the point based approach and the polygon based approach in a GIS based hedonic analysis was compared using the apartment housing market data from the north eastern part of the city of Seoul and Davidson and MacKinnon Test. The results from this study indicate two things. First, two approaches can produce substantially different results in a hedonic price model estimation. Second, the polygon based approach produces a hedonic price model which explains the price variations better than the point based approach. These findings suggest that Korean researchers who are interested in improving quality of hedonic price model estimations and use GIS to measure the location variables for hedonic price models should consider using the polygon based approach with the point based approach. This is because the polygon based approach can produce the location variables with the shortest straight line distances and can explain the housing price variations well.

• Journal of the Korea Society of Computer and Information
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• 제16권9호
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• pp.69-76
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• 2011

According to the related reports, about 60 percents of ship collisions have resulted from operating mistake caused by human factor. Specially, the report said that negligence of observation caused 66.8 percents of the accidents due to a human factor. Hence automatic detection and tracking of an object from an IR images are crucial for safety navigation because it can relieve officer's burden and remedies imperfections of human visual system. In this paper, we present a method to detect an object such as ship, rock and buoy from a sea IR image. Most edge directions of the sea image are horizontal and most vertical edges come out from the object areas. The presented method uses them as a characteristic for the object detection. Vertical edges are extracted from the input image and isolated edges are eliminated. Then morphological closing operation is performed on the vertical edges. This caused vertical edges that actually compose an object be connected and become an object candidate region. Next, reference object regions are extracted using horizontal edges, which appear on the boundaries between surface of the sea and the objects. Finally, object regions are acquired by sequentially integrating reference region and object candidate regions.

• Journal of Internet Computing and Services
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• 제16권1호
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• pp.91-100
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• 2015

Recently many companies began to feel the pressures of cost savings due to the global recession, so they have been interested in the Cloud Computing. Cloud Computing is one of using method of IT resources through the network. Users can borrow softwares or hardwares instead of buying them. Many people expect remarkable growth in Cloud Computing industry because of it's effectiveness. But Cloud Computing industry is still at an early stage. Especially, people who in the public sector hesitate to adopt Cloud Computing Services due to security issues and their conservative views. Also, they just have limited understanding, so we need to investigate what they really know and understand. Researches about the Cloud Computing generally focus on technical issues, so we can hardly find researches reference for decision making in considering the services. The study aims to investigate diverse factors for agencies' adoption decisions, such as benefits, costs, and risk in developing the most ideal type of cloud computing service for them, and performs priority analyses by applying ANP (Analytic Network Process). The results identify that features pertaining to the risk properties were considered the most significant factors. According to this research, the usage of private cloud computing services may prove to be appropriate for public environment in Korea. The study will hopefully provide the guideline to many governmental agencies and service providers, and assist the related authorities with cloud computing policy in coming up with the relevant regulations.

• The Journal of the Korea Contents Association
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• 제20권1호
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• pp.364-377
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• 2020

Although it is never easy to create charming characters that people can relate to, well-formed characters have the power to enable the audience to not only empathize but identify with them. Thus, there is a need for us to examine the parts that make up a well-formed character. According to empathy theory, when the character in the play has a human face that is not different from me, I can feel familiarity and human empathy. Rather than perfection without loopholes, I relate to and sympathize with someone who looks similar to me, with many mistakes and some lack. This study aims to examine the attractiveness of characters in narrative dramas in terms of defects and internal growth. To do this, we tried to compare the setting, evaluation, and performance of characters based on the movie worldviews of two famous brands (DC and Marble), which can be compared directly. I looked at it. In conclusion, the work of hero character but human character setting based on internal growth not only has high evaluation and public evaluation, but also high sales, and thus direct and indirect correlation with the public favorability is significant.