• The Korean Journal of Applied Statistics
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• v.17 no.2
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• pp.239-252
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• 2004

It is known that the domestic and the U.S. stock prices tend to move together as those markets are closely interrelated. In this study, cointegration and causal relationships among the four stock price indexes of KOSPI, KOSDAQ, DOWJONES and NASDAQ are carefully investigated for the period of declining stock prices in the long run. When all indexes move in a similar fashion, cointegration does not exist and the causal linkages between the domestic and the U.S. stock prices appear relatively complex. On the other hand, when the domestic and the V.S. stock prices move in a different manner, cointegration exists and the causal relationships appear relatively simple. NASDAQ is apparently found to lead the domestic stock market in both periods, which is consistent with the actual market situation when the If industry is under recession.

• Journal of Ocean Engineering and Technology
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• v.33 no.2
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• pp.196-202
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• 2019

In this study, the excessive noise and vibration phenomena of a high-speed Ro/Ro passenger ship were analyzed, and a countermeasure was taken based on them. This ship was granted a comfort class notation by the classification society, which was COMFORT-VIBRATION-II and COMFORT-NOISE-CREW-II. However, unfortunately, excessive noise and vibration in the aft part of the ship were delivered from the twin shaft propellers, and therefore the Class Requirement was not satisfied before delivery. In order to obtain the class notation, all of the concerned parties came to an agreement to reduce the noise and vibration level during operation after delivery because a seasonal ferry service was already scheduled and the cabin was fully booked. The root cause of the massive amount of noise and vibration was mainly the propeller-induced excitation pulse and beating that occurred from the mismatch of the rotating speeds of the two shaft lines. A 1st order vibrating force and beating phenomena existed in the propeller. Thus, a reduction of the excitation force, elimination of the beating phenomena, and decrease of the noise level at the aft area cabins and public spaces were required. In addition, structural reinforcements were conducted using pillars and additional girders at the aft part of the decks.

• Journal of the Korean Data and Information Science Society
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• v.22 no.3
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• pp.423-436
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• 2011

Many of the theoretical studies have considered herd behavior as a source of the volatility in financial markets, but there have been few empirical studies on the dynamic herding due to the technical difficulty of detecting herd behavior with time-series data. In this context, this paper proposes a new method for measuring time-varying herd behavior based on QR-GARCH model. Using daily data of KOSPI stocks, this paper provides some empirical evidence for strong and volatile herding among traders of stocks of medium firms, and shows that time-varying herd behavior in traders of some stocks has persistent autocorrelation.

• Journal of Educational Research in Mathematics
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• v.23 no.4
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• pp.423-448
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• 2013

The journals provide an academic arena for researchers in specific academic field, and play a crucial role in the process of formation and development of the academic field. The main purpose of this research was to investigate the familiarity, reputation, applicability, and preference of mathematics education journals. For this purpose, a survey was conducted for mathematics educators. As a result, the three journals , , and were notably preferred by mathematics educators, and the scores of familiarity, reputation, applicability, and preference were almost synchronized. On the other hand, mutual preference of mathematics education, mathematics, and education journals is an indicator of the communication among related academic fields. However, mathematics education researchers showed little preference toward mathematics and education journals, and vice versa.

• The Korean Journal of Applied Statistics
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• v.34 no.1
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• pp.115-126
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• 2021

Central banks communicate with the market through a statement on the direction of monetary policy while implementing monetary policy. The rapid contraction of the global economy due to the recent Covid-19 pandemic could be compared to the crisis situation during the 2008 global financial crisis. In this paper, we analyzed the text data from the monetary policy statements of the Bank of Korea and Fed reflecting monetary policy directions focusing on how they were affected in the face of a global crisis. For analysis, we collected the text data of the two countries' monetary policy direction reports published from October 1999 to September 2020. We examined the semantic features using word cloud and word embedding, and analyzed the trend of the similarity between two countries' documents through a piecewise regression tree model. The visualization result shows that both the Bank of Korea and the US Fed have published the statements with refined words of clear meaning for transparent and effective communication with the market. The analysis of the dissimilarity trend of documents in both countries also shows that there exists a sense of synchronization between them as the rapid changes in the global economic environment affect monetary policy.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.25 no.8A
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• pp.1238-1246
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• 2000

In a multi-channel network based on wavelength division multiplexing (WDM), an efficient protocol is needed for transmitter and receiver to be tuned to same wavelength during message transmission time. This paper proposes a message scheduling protocol that can efficiently support variable-sized messages, where tunable transceiver has nonzero tuning time. In this protocol, once a node reserves one data channel, it can persistently use the reserved channel till message transmission is finished. Therefore, overhead due to tuning time of the tunable transceiver can be reduced. Moreover, the protocol does not require any global information. Therefore, it can operate independently of the change of the number of nodes, and any new node can join the network at anytime without requiring network initialization. With this protocol, one can avoid data channel and destination conflicts. The protocol is analyzed with a finite population model and the throughput-delay characteristics are investigated as performance measures.

• Management & Information Systems Review
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• v.29 no.2
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• pp.97-118
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• 2010

This paper explores the mean and volatility spillover effects among Chinese, Korean, and the U.S. stock markets during the Asian and global financial crises. We found that, during the Asian Financial crisis, there was no mean spillover effect to the Chinese stock markets. However, there were reciprocal mean spillover effects between the U.S. and the Korean market. This implies that Korean market was open, while Chinese market was secluded from the international financial market at that time. The negative volatility spillover effect between the U.S. and China reinforces this finding. During the global financial crisis, there was reciprocal mean spillover effect between the U.S. and China, and between the U.S. and Korea. This may reflect the fact that Chinese market has opened to the international financial market. However, the volatility spillover effect does not exist between China and the U.S., while the U.S. and Korea has reciprocal volatility spillover effect to each other. These findings may imply that China is still in the process of opening her stock market to international investors.

• Journal of Digital Convergence
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• v.18 no.9
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• pp.103-112
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• 2020

The purpose of this study is to examine the current status and components of Korean National Debt and to analyze the effects of each component on National Debt. In the Korean Statistical Information Service (KOSIS), we searched for data such as General Accounting Deficit Conservation, For Foreign Exchange Market Stabilization, For Common Housing Stability, Local Government Net Debt Public Funds, etc that constitute National Debt. The analysis period used a total of 23 annual data from 1997 to 2019. The data collected in this study use the rate of change compared to the previous year for each component. Using this, this study attempted index analysis, numerical analysis, and model analysis. Correlation analysis result, the National Debt has a high relationship with the For Common Housing Stability. For Foreign Exchange Market Stabilization, Public Funds, etc., but has a low relationship with the Local Government Net Debt. Since 1997, National Debt has been increasing similarly to the For Foreign Exchange Market Stabilization, For Common Housing Stability and Public Funds etc. Since 2020, Korea is expected to increase significantly in terms of For Common Housing Stability and Public Funds, etc due to Corona19. At a time when the global economic situation is difficult, Korea's National Debt is expected to increase significantly due to the use of national disaster subsidies. However, if possible, the government expects to operate efficiently for economic growth and financial market stability.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.12 no.1
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• pp.80-90
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• 2011

The purposes of this study are clarifying the characteristics of women's hair style in the late Joseon Dynasty by inquiring into that hair style and, by extension, having a new understanding of the aesthetic consciousness of women in those times. The typical hair style of married Joseon women was Ungeonmeori and Jjokmeori, with Ungeonmeori being much more popular. Regardless of socioeconomic status, women used a big Gache as long as conditions permitted. Meanwhile, some women who led the trend or followed the national policy did Jjokmeori and wore Jokdoori. The Joseon Dynasty had a strict clothing system. However, giseangs were free from this restriction and they were free at attire. Therefore, they led the fashion trend. Both noble and common women followed the trend, imitating giseangs' attire. Women's hair style was used as a tool to express one's personality in the late Joseon Dynasty when the hierarchy was already weakened. In fact, it seems that women in those times cared more about hair style trend than clothing trend. This means that those women already had such a high quality of aesthetic consciousness that they showed their hair which is the closest to the face to advantage.

• Journal of Digital Convergence
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• v.16 no.12
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• pp.175-183
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• 2018

This study analyzes determinants of bond returns in terms of systematic risk versus idiosyncratic risk by examining relationship among those factors. First we examined the cross-sectional determinants of corporate bond returns with Korean bond market data from 2001 to 2014. This paper uses term factor and default factor for systematic risk, and duration factor and credit rating factor for idiosyncratic risk. The empirical result shows that systematic risk can explain cross-sectional differences of bond returns rather than idiosyncratic risk which is the same result in advanced markets(US or Europe). This result is different from the previous Korean studies which showed that idiosyncratic risk is more important than systematic risk in Korean bond market. The reason for the different result may be the longer sample period which includes the most recent period. It is insisted that Korean bond market is getting more synchronized with the advanced bond market. In conclusion, this empirical result implies that Korean bond portfolio managers should focus on systematic risk, which is contrary to current system in Korean asset management industry.