• International Journal of Contents
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• 제3권1호
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• pp.19-23
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• 2007

Recently, several main-memory index structures have been proposed to reduce the impact of secondary cache misses. In mainmemory storage systems, secondary cache misses have a substantial effect on the performance of index structures. However, recent studies still stiffer from secondary cache misses when visiting each level of index tree. In this paper, we propose a new index structure that minimizes the total amount of cache miss latency. The proposed index structure prefetched grandchildren of a current node. The basic structure of the proposed index structure is based on that of the CSB+-Tree, which uses the concept of a node group to increase fan-out. However, the insert algorithm of the proposed index structure significantly reduces the cost of a split. The superiority of our algorithm is shown through performance evaluation.

• 천문학회보
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• 제41권1호
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• pp.79.3-80
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• 2016

We have investigated the correlation analysis between global temperature anomaly and two main factors: geomagnetic activity (aa index) of Earth external factor and CO2 of Earth internal factor. For this, we used NOAA Global Surface Temperature anomaly (Ta) data from 1868 to 2015. The aa index indicates the geomagnetic activity measured at two anti-podal subauroral stations (Canberra Australia and Hartland England) and the CO2 data come from historical ice core records and NOAA/ESRL data. From the comparison between (Ta) and aa index, we found several interesting things, First, the linear correlation coefficient between two parameters increases until 1985 and then decreases rapidly. Second, the scattered plot between two parameters shows a boundary of the correlation tendency (positive and negative correlation) near 1985. A partial correlation of (Ta) and two main factors (aa index, CO2) also shows that the geomagnetic effect (aa index) is dominant until about 1985 and the CO2 effect becomes much more important after then. These results indicate that the CO2 effect become very an important factor since at least 1985. For a further analysis, we simply assume that Ta = Ta(aa)+Ta(CO2) and made a linear regression between (Ta) and aa index from 1868 to 2015. A linear model is then made from the linear regression between energy consumption (a proxy of CO2 effect) and Ta-Ta(aa) since 1985. Our results will be discussed in view of the prediction of global warming.

• 한국정보과학회논문지:데이타베이스
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• 제31권6호
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• pp.675-683
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• 2004

주기억장치 상주형 색인구조에서는 2차 캐쉬 실패가 성능에 매우 큰 영향을 미친다. 기존에 제안된 주기억장치 상주형 색인구조들은 2차 캐쉬 실패를 고려하긴 했지만 여전히 트리의 각 레벨을 접근할 때는 2차 캐쉬 실패가 발생한다. 본 논문에서는 이러한 문제점을 인식하고 트리 순회 시 각 레벨을 방문할 때도 캐쉬 실패가 발생하지 알는 주기억장치 색인구조를 제안한다. 제안하는 색인구조인 lpCSB+-트리는 다음 레벨에서 방문할 가능성이 있는 노드들을 프리페치하여 다음 레벨을 방문할 때도 캐쉬 실패가 발생하지 않도록 한다. 또한, 기본적인 구조는 노드그룹 개념을 이용하여 노드의 팬-아웃을 증가시키는 CSB+-트리에 기반하지만 CSB+-트리의 단점인 분팔 비용의 증가문제를 해결하기 위한 방법을 제안한다. 성능평가를 통해 기존의 색인구조와 비교하여 제안하는 색인구조의 우수성을 보인다.

• Journal of Astronomy and Space Sciences
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• 제30권1호
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• pp.43-48
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• 2013

The geomagnetic activity shows the semiannual variation stronger in vernal and autumnal equinoxes than in summer and winter solstices. The semiannual variation has been explained by three main hypotheses such as Axial hypothesis, Equinoctial hypothesis, and Russell-McPherron Effect. Many studies using the various geomagnetic indices have done to support three main hypotheses. In recent, Oh & Yi (2011) examined the solar magnetic polarity dependency of the geomagnetic storm occurrence defined by Dst index. They reported that there is no dependency of the semiannual variation on the sign of the solar polar fields. This study examines the solar magnetic polarity dependency of quiet time geomagnetic activity. Using Dxt index (Karinen & Mursula 2005) and Dcx index (Mursula & Karinen 2005) which are recently suggested, in addition to Dst index, we analyze the data of three-year at each solar minimum for eight solar cycles since 1932. As a result, the geomagnetic activity is stronger in the period that the solar magnetic polarity is anti-parallel with the Earth's magnetic polarity. There exists the difference between vernal and autumnal equinoxes regarding the solar magnetic polarity dependency. However, the difference is not statistically significant. Thus, we conclude that there is no solar magnetic polarity dependency of the semiannual variation for quiet time geomagnetic activity.

• International journal of advanced smart convergence
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• 제11권2호
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• pp.142-152
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• 2022

We study confirmed the relationship between the adversity index, entrepreneurial orientation, and organizational learning competency perceived by organizational members as follows. First, the adversity index showed a positive (+) effect on entrepreneurial orientation (hypothesis 1) and organizational learning competency (hypothesis 2). Second, the entrepreneurial orientation was statistically significant in organizational learning competency (hypothesis 3). Third, the partial mediating role of entrepreneurial orientation (Hypothesis 4) was confirmed in the process of the adversity index affecting organizational learning competency. Meanwhile, the main implications of this study are as follows. First, it is the aspect that provides additional theoretical implications in the reality that studies on the adversity index and entrepreneurial orientation that affect organizational learning competency are lacking. Second, it is the aspect that the importance of adversity index and start-up orientation was confirmed in improving organizational learning competency based on securing differentiated competitiveness for the advancement of the organization's sustainability management system. In addition, it is the aspect of drawing practical implications for strategic human resource management and human resource development to systematically improve it.

• 한국우주과학회:학술대회논문집(한국우주과학회보)
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• 한국우주과학회 2008년도 한국우주과학회보 제17권2호
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• pp.24.2-24.2
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• 2008

We have examined the relative contributions of representative space weather proxies (geomagnetic aa index) to global warming (Global temperature anomaly) and compared them with that of green house effect characterized CO2 content from 1868 to 2005. For this we used Hadcrut3 temperature anomaly (Ta) data, aa index taken at two anti-podal subauroral stations (Canberra Australia and hartland England), and the CO2 data come from historical ice core records. From the comparison between Ta and aa index, we found several interesting results: (1) the linear correlation coefficient between two parameters increases until 1990 and then decreases rapidly, and (2) the scattered plots between two parameters shows different patterns before and after 1990. A partial correlation of Ta and two quantities (aa, CO2) also shows that the geomagnetic effect (aa index) is dominant until about 1990 and the CO2 effect becomes much more important after then. These results imply that the green house effect become very important since at least 1990. For a further analysis, we simply assume that Ta (total) = Ta (aa) + Ta (CO2) and made a linear regression between Ta and aa index from 1868 to 1990. A linear model is then made from the linear regression between energy consumption (a proxy of CO2 effect) and Ta (total) - Ta (aa) since 1990. This linear model makes it possible to predict the temperature anomaly in 2030, about 1 degree higher than the present temperature, which is much larger than in the previous century.

• 인터넷정보학회논문지
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• 제4권6호
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• pp.75-86
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• 2003

주기억장치 상주형 색인구조에서는 2차 캐쉬 실패가 성능에 매우 큰 영향을 미친다. 기존에 제안된 주기억장치 상주형 색인구조들은 2차 캐쉬 실패를 고려하긴 했지만 여전히 트리의 각 레벨을 접근할 때는 2차 캐쉬 실패가 발생한다. 본 논문에서는 이러한 문제점을 인식하고 트리 순회 시 각 레벨을 방문할 때도 캐쉬 실패가 발생하지 않는 주기억장치 색인구조를 제안한다. 제안하는 색인구조인 IpCSB+-트리는 다음 레벨에서 방문할 가능성이 있는 노드들을 프리페치하여 다음 레벨을 방문할 때도 캐쉬 실패가 발생하지 않도록 한다. 또한, 기본적인 구조는 노드그룹 개념을 이용하여 노드의 팬-아웃을 증가시키는 CSB+-트리에 기반하지만 CSB+-트리의 단점인 분한 비용의 증가문제를 해결하기 위한 방법을 제안한다. 성능평가를 통해 기존의 색인구조와 비교하여 제안하는 색인구조의 우수성을 보인다.

• Journal of the Korean Data Analysis Society
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• 제20권6호
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• pp.2759-2769
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• 2018

The behavioral finance view on the existence of asset pricing anomalies is based on two factors: investors' sentiment and limits to arbitrage. This paper tries to examine the effect of investors' sentiment on the stock price in the Korean stock market. In order to measure investors' sentiment, we constructed the sentiment index using principal component of five sentiment variables. By using sentiment index as an additional independent variable to three risk factors, impacts of the sentiment index on individual stocks and 25 portfolios sorted by BM-size are examined. Main results found are as follows: 1) not only all three risk factors show positive impacts on the return of individual stock, but also the sentiment index has a positive impact. SI alone explains 15% of individual return variation. 2) among four independent variables, the most important factor turned out to be the market risk factor and investors' sentiment has better explanatory power on stock price than the size effect. 3) after controlling the market risk factor, the coefficient of the sentiment index for the smallest size and highest book/market value portfolios is significantly positive. 4) all the coefficients of the sentiment index for 25 portfolios sorted by BM-size have significant positive value after controlling size or (and) value.

• Environmental Engineering Research
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• 제23권2호
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• pp.150-158
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• 2018

The deteriorating role of Nakdong River due to the Four Major Rivers Project has caused a series of problems, including water pollution, drying streams, aggravation of the hydroecology. Geumho River and Gyeongseong-cheon had a higher concentration index and is believed to impact the water quality of the main stream. The influence index of Geumho River and Nam River between 2015 and 2016, which have a large amount of discharge, was the highest among the tributaries in terms of the load material balance. Showing the highest average concentration and average load in the index assessment, Geumho River is believed to require an intensive management for improving the water quality of the main stream. Furthermore, when the cumulative percentage of the average concentration and average load was compared based on the water quality improvement of the tributaries mixed to Nakdong River, which was set to 60%, Geumho River, Nam River, Topyeong-cheon, and Cha-cheon, which showed the highest ratio in that order, were determined to require a water quality management program as a priority.

• 대한인간공학회지
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• 제31권2호
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• pp.337-343
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• 2012

Objective: The aim of this study was to determine the effect of abdominal-compression belt in one leg standing on balance in normal adult. Background: With the effects of increased intra-abdominal pressure, the abdominal-compression belt is contributing to a static balance control. However, specific study is still insufficient. Method: Forty subjects were randomly allocated to two groups: control(n=20) and experimental group(n=20), respectively. The experimental group used an abdominal-compression belt, whereas the control group did not that. All subjects were educated using pressure biofeedback unit and ultrasound imaging for exact application by abdominal-compression belt. Main outcome measurement was used a general stability index, fourier harmony index, weight distribution index, and fall index in tetrax balance system. Results: Experimental group improved significantly on general stability, only 2 factors(eyes closed with head turned forward and eyes closed with head turned backward) among fourier harmony index, and fall index, However, weight distribution index did not revealed significant difference. Conclusion: The findings suggest that application of abdominal-compression belt could be effective on improving balance ability in one leg standing of normal adults. Application: The results of the abdominal-compression belt might help to control balance in workers.