• The Korean Journal of Financial Management
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• v.25 no.3
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• pp.1-32
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• 2008

This study examines the changes and determinants of cash to assets ratios(cash ratios) by analyzing 14,016 Korean manufacturing firms sample for the period of $1999{\sim}2004$. The major findings can be summarized as follows. First, the average cash ratios for Korean manufacturing firms have increased from 4.7 percent of 1999 to 5.2 percent of 2004. In addition, the average cash holdings per firm also have increased from 4.3 billion Won to 8.0 billion Won during the same period. However, the capital expenditures relative to cash ratios or operating cash flow have decreased significantly, confirming the notion that physical investment of Korean manufacturing sector has been shrinking recently. Second, in regression tests with panel data, the coefficients of target adjustment variables show the expected negative signs, but coefficients of the deficit of fund variables show the unexpected positive signs. Thus, the evidence seems to be supportive of static tradeoff model of cash holdings. Third, in regression tests to find the determinants of cash ratios, most of the variables show similar results as the previous studies. However, in terms of adjusted coefficient of determination and F-statistic, the firm-characteristic variables suggested by static trade-off theory have more explanatory power than the variables suggested by pecking order theory.

• The KIPS Transactions:PartD
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• v.16D no.4
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• pp.475-486
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• 2009

Data cube plays an important role in multi-dimensional, multi-level data analysis. Meeting on-line analysis requirements of data stream, several cube structures have been proposed for OLAP on data stream, such as stream cube, flowcube, S-cube. Since it is costly to construct data cube and execute ad-hoc OLAP queries, more research works should be done considering efficient data structure, query method and algorithms. Stream cube uses H-cubing to compute selected cuboids and store the computed cells in an H-tree, which form the cuboids along popular-path. However, the H-tree layoutis disorderly and H-cubing method relies too much on popular path.In this paper, first, we propose $H^*$-tree, an improved data structure, which makes the retrieval operation in tree structure more efficient. Second, we propose an improved cubing method, $H^*$-cubing, with respect to computing the cuboids that cannot be retrieved along popular-path when an ad-hoc OLAP query is executed. $H^*$-tree construction and $H^*$-cubing algorithms are given. Performance study turns out that during the construction step, $H^*$-tree outperforms H-tree with a more desirable trade-off between time and memory usage, and $H^*$-cubing is better adapted to ad-hoc OLAP querieswith respect to the factors such as time and memory space.

• Journal of the Korean Society of Marine Environment & Safety
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• v.27 no.5
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• pp.557-565
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• 2021

Path-following control is considered as one of the most fundamental skills to realize autonomous navigation of marine vessels in the ocean. This study addresses with the path-following control for a ship in which there are environmental disturbances in the directions of the surge, sway, and yaw motions. The guiding principle and back-stepping method was utilized to solve the ship's tracking problem on the reference path generated by a virtual ship. For path-following control, error dynamics is one of the most important skills, and it extends to the research fields of automatic collision avoidance and automatic berthing control. The algorithms for the guiding principles and error variables have been verified by numerical simulation. As a result, most error variables converged to zero values with the controller except for the yaw angle error. One of the most interesting results is that the tracking errors of path-following control between two ships are smaller than the existing safe passing distances considering interaction forces from near passing ships. Moreover, a trade-off between tracking performance and the ship's safety should be considered for determining the proper control parameters to prevent the destructive failure of actuators such as propellers, fins, and rudders during the path-following of marine vessels.

• The Journal of the Korea Contents Association
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• v.21 no.9
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• pp.176-183
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• 2021

Digital medical technology is very effective and at the same time faces the challenge of protecting privacy. However, for contact tracking and exposure notification apps in COVID-19 environment, there is always a trade-off between privacy measures and the effectiveness of the app's use. Today, many countries have developed and used contact tracking and exposure notification apps in various forms to prevent the spread of COVID-19, but the suspicion of digital surveillance (digital panopticon) is unavoidable. Therefore, this study aims to identify the factors of personal information infringement and dissatisfaction through text mining analysis by extracting user reviews of "Self-Quarantine Safety Protection" in Korea. As a result of the text mining analysis, we derived four groups, 'Address recognition error', 'Exit warning error', 'Access error', and 'App. program error'. Since 'Address recognition error' and 'Exit warning error' can give the app users a strong perception that they are keeping under surveillanc by the app, transparent management of personal information protection and consent procedures related to personal information collection are required. In addition, if the other two groups are not corrected immediately due to an error in an app function or a program bug, the complaints of users can be maximized and a protest against the monitor can be raised.

• International Area Studies Review
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• v.15 no.2
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• pp.331-350
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• 2011

This paper analyzes balance of goods for a panel data of 56 industry classification in the MTI from 1980 to 2009. This study also develops the equilibrium adjustment process, which is a trade-off between the adjustment costs towards equilibrium costs for balance of goods and the cost of being in disequilibrium. In this framework, the GMM estimation procedure is used to estimate this dynamic panel model consistently. It is found that equilibrium balances of goods in Korean adjust to the speed is very slow to 0.0389. because of this is necessary to adjust the equilibrium goods balance as the cost of goods balance deficit is larger than by the cost. In addition, the real income elasticity for goods balance of resin in Japan and Korea, the real income elasticity 4.38168 and -0.835225, respectively, the marks were consistent with economic theory. The exchange rate elasticity of goods balance in japan to 0.478435 were found in the inelastic.

• Journal of International Area Studies (JIAS)
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• v.19 no.1
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• pp.157-204
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• 2015

This paper explores firm-specific internal and external determinants of the sustainability of "the social innovative enterprise(SIE)" by conducting a case research on Fragrant People Co. In doing so, some business and policy implications have been produced concerning the components and determinants of the sustainability of the SIE. First, entrepreneurship is a necessary factor for the survival and growth of the SIE. A social entrepreneur does manage effectively social and economic opportunities for making economic and social values interact dynamically beyond their trade-off relationship and creating new market chances. Second, the SIE also needs competitive advantages as commercial enterprises do. Valuable resources to be used for taking opportunities and avoiding threats, rare resources not to be possessed by other firms, and resources not to be easily imitated by competitors are extremely necessary for achieving objectives of the SIE. In addition, a firm must be well organized for those valuable, rare, and not easily imitated resources. Economic performance achieved by the SIE gives a birth to its financial independence, contributing to the realization of symmetric social performance. Third, the SIEs will be allowed to seek symmetrically economic and social performance only when they use sufficiently competitive advantage resources with entrepreneurship, which is composed of innovativeness, proactiveness, agility and risk-taking attitudes. In doing so, financial assistance from central or local governments may not ensure the sustainability of the SIEs. In addition, vision & value sharing(person-organization fit) can ensure the sustainability of the SIEs only when it is connected with the organizational commitment.

• Journal of Korea Foundry Society
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• v.41 no.3
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• pp.252-259
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• 2021

The magnesium is one of the important alloying elements in the conventional aluminum alloys. The addition of magnesium to aluminum is well known to increase the mechanical strength of the aluminum without the trade-off of the decreased elongation. However, the content of magnesium in aluminum alloys has been limited to be lower than about 5wt.% because of the high oxidation tendency of magnesium element during the manufacturing processes such as casting, hot-forming and post heat-treatments, which can deteriorate the quality and properties of the final products. In this study, new 'ECO-Almag6~9' (containing 6~9wt%Mg) alloys were investigated to be made of the ECO-Mg master alloy, which has been invented to reduce the oxidation tendency of itself. It was successfully demonstrated that ECO-Almag6~9 alloys can be fabricated through the mass-production facilities of DC casting and extrusion routes without the problems of magnesium oxidation. In addition, it was confirmed that the strength and ductility were simultaneously improved due to the addition of high magnesium contents.

• The Journal of the Convergence on Culture Technology
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• v.7 no.2
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• pp.239-246
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• 2021

Unification means the change of the economic system from 'Planned Economy' of the North Korea to 'Market Economy' of the South Korea. Therefore, it may cause confusions and difficulties for North Koreans who have been under planned economy for ages. So, we need to take the perspective of behavioral economics for the effective education. First of all, it is about overall finance, which contains the record of financial transactions, effect of inflation, investors' bounded rationality, and choice difficulty of financial products. Second, it is about borrowings, which includes the credit management, interest rate of difference among financial institutions. Third, it is about investment on financial products, which includes the effect of cost on returns, difference between compound interest and simple interest, trade-off between expected return and risk, market and non-market risks, the importance of diversification, and passive & aggressive investments.

• Journal of the Korea Society for Simulation
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• v.18 no.4
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• pp.39-47
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• 2009

Recently, the threat of DDoS attacks is increasing and many companies are planned to deploy the DDoS defense solutions in their networks. The DDoS attack usually transmits heavy traffic data to networks or servers and they cannot handle the normal service requests because of running out of resources. Since it is very hard to prevent the DDoS attack beforehand, the strategic plan is very important. In this work, we have conducted modeling and simulation of the DDoS attack by changing the number of servers and estimated the duration that services are available. In this work, the modeling and simulation is conducted using OPNET Modeler. The simulation result can be used as a parameter of trade-off analysis of DDoS defense cost and the service's value. In addition, we have presented a way of estimating the cost effectiveness in deployment of the DDoS defense system.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.29 no.6D
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• pp.711-717
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• 2009

This study develops model for analysis of relationship between major node (Interchange in expressway) and land price formation of apartments along with Seoul Belt Expressway by using CHAID analysis. The results show that first, regions(outer side: Gyeongido, inner side: Seoul) on the line of Seoul Belt Expressway are different and a graph generally show llinear relationships between land price and traffic node but it does not; second, CHAID analysis shows two different spatial distribution at the point of 2.6km in the outer side, but three different spatial distribution at the point of 1.4km and 3.8km in the inner side. In other words, traffic access does not necessarily guarantee high housing price since the graphs shows land price related to composite spatial distribution. This implies that residential environments (highway noise and regional discontinuity) and traffic accessibility cause mutual interaction to generate this phenomenon. Therefore, the highway IC landprice model will be beneficial for calculation of land price in New Town which constantly is being built along the highway.