• Journal of the Korea Society of Computer and Information
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• v.20 no.6
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• pp.1-11
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• 2015

Recently, NAND flash memories are used for storage devices because of fast access speed and low-power. However, applications of FTL on low power computing devices lead to heavy workloads which result in a memory requirement and an implementation overhead. Consequently, studies of B+-Tree on embedded devices without the FTL have been proposed. The studies of B+-Tree are optimized for performance of inserting and updating records, considering to disadvantages of the NAND flash memory that it can not support in-place update. However, if a general garbage collection method is applied to the previous studies of B+-Tree, a performance of the B+-Tree is reduced, because it generates a rearrangement of the B+-Tree by changing of page positions on the NAND flash memory. Therefor, we propose a novel garbage collection method which can apply to the B+-Tree based on the NAND flash memory without the FTL. The proposed garbage collection method does not generate a rearrangement of the B+-Tree by using a block information table and a proxy block. We implemented the B+-Tree and ${\mu}$-Tree with the proposed garbage collection on physical devices with the NAND flash memory. In experiment results, the proposed garbage collection scheme compared to greedy algorithm garbage collection scheme increased the number of inserted keys by up to about 73% on B+-Tree and decreased elapsed time of garbage collection by up to about 39% on ${\mu}$-Tree.

• Management & Information Systems Review
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• v.32 no.5
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• pp.261-285
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• 2013

In this paper, examined relationship between Earnings Management and Conservatism. For analysis of this purpose, we applied the Earnings Loss Avoidance Firms and Big-bath Firms. The results are as follows. First, conservative of Earnings Loss Avoidance Firms(sample I, II) is lower than the controlled companies. And Big-bath firms(sample III, IV) is higher than the controlled companies. This is a negative relationship between conservative and earning management. These results are consistent with previous research results. Second, When analyzing the Earnings Loss Avoidance Firms(sample I, II), Results are presented that conservative and earning management related to positive. These results reflect the company to Investors' demand for conservatism.

• Asia-Pacific Journal of Business Venturing and Entrepreneurship
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• v.16 no.3
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• pp.145-158
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• 2021

The purpose of this study is to examine the influence of the ownership structure of unlisted firms on KOSDAQ listing. There are few studies analyzing the characteristics of listing success based on ownership structure. For startup executives, there is not enough data to refer to the ownership structure that can increase the possibility of listing. This paper examines the effects of ownership structure on IPO success through comparison between listed successful and failed companies among the companies in application for KOSDAQ listing eligibility review. The major findings are as follows; (1) Venture capital investment and shareholding have a statistically positive effect on the success of KOSDAQ listing. This results indicate that the venture capital's investment alleviate the problem of information asymmetry, and it is a valid signal for market participants. The result means the role of venture capital seems to be important when companies are listed on the KOSDAQ. (2) The largest shareholder's stake has an inverted-U shape relationship with listing success. In other words, the ownership concentration mitigates moral hazard problem, which leads to listing success. However, if the ownership concentration exceeds a certain level, the chances of success in listing will decrease due to concerns over the pursuit of private interests. The result suggests that the largest shareholder's stake reduce agency problem. This study academically contributes to the existing literature by demonstrating the ownership structure affects IPOs, and explaining the results based on agent theory and signal theory. Our results provide practical implications for companies preparing for an IPO on the KOSDAQ.

• Journal of Korea Water Resources Association
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• v.56 no.5
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• pp.337-345
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• 2023

Monitoring river microplastics is a challenging task since it is a time-consuming and high-cost process. The use of a physical model to have a better understanding of river microplastics' behaviors can complement the challenging monitoring process. However, there have been very limited studies on modeling river microplastics. In this study, therefore, we evaluated the applicability of one commonly used river water quality model, i.e., the Water Quality Analysis Simulation Program (WASP), in simulating the microplastic concentration in the river environment. We simulated the microplastic concentration in the Anyangcheon stream using the WASP's biochemical oxygen demand (BOD) and suspended solid (SS) variables as possible surrogate variables for the microplastics. Simulation analyses indicate that the SS state variable performs better than the BOD state variable to mimic the observed concentrations of microplastics. This is because of the characteristics of each water quality parameter; the BOD variable, a biochemical indicator, is inappropriate for modeling the behaviors of microplastics, which have generally constant biochemical features. In contrast, the SS variable, which has similar physical behaviors, followed the observed patterns of the microplastic concentrations well. To build a more advanced and accurate model for simulating the microplastic concentration, comprehensive and long-term monitoring studies of the river microplastics under different environmental conditions are needed, and the unit of microplastic concentration should be carefully addressed before its modeling application.

• Management & Information Systems Review
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• v.33 no.5
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• pp.171-184
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• 2014

This paper investigate the impact of external financing constraints(EFC) on the dividend policy(cash dividend ratio) and the impact of interaction of ownership structure((1)the percentage of shares held by external blockholder who owns at least 5% of equity(5% BHR), (2) the percentage of shares held by foreign investors(Foreign), (3) the percentage of shares by insider shareholders(Insider)) and external financing constraints on the dividend policy. The purpose mentioned above are empirically tested using 370 firm-year data listed on the Korean Exchange(KRX) with multiple regression method. Summarizing the results of analysis as following; Firstly, we find that EFC has negative relationship with cash dividend ratio. Secondly, interaction of 5% BHR and EFC has positive relationship with cash dividend ratio. Also, interaction of Foreign and EFC has positive relationship with cash dividend ratio. But, Insider and EFC has negative relationship with cash dividend ratio. This study contributes to research related to dividend policy by recognizing that ownership structure influences the dividend policy.

• The Korean Journal of Financial Management
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• v.25 no.2
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• pp.137-164
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• 2008

This paper examines the operating performance of firms that for a four-year period, held more than 15% of their assets in cash and cash equivalents. During next four years, operating performance of firms maintaining high cash persistently is greater than the performance of firms matched by size and industry or firms adopting transitory high cash policy. Furthermore, the effect of persistent cash holdings on operating performance depends on the ownership structure and the level of information asymmetry. Foreign investors deteriorate the operating performance of high cash firms, suggesting that potential M&A and the pressure of excessive dividend reduce the usefulness of cash. The level of information asymmetry enhances the operating performance for the firms adopting persistent high cash policy. It suggests that cash holdings reduce the costly external financing and underinvestment problem for firms with high information asymmetry.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.19 no.3
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• pp.493-499
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• 2015

In Korea mobile phone subscribers exceeded 1 million people in 1995, and ten million people in 1998. Prevalence of the mobile phone increased dramatically over 110% compared to the population. Almost every family members including children uses more than one mobile terminal. Mobile phone is obviously more necessary good than washer, vacuum cleaner and passenger car. Our daily life are conveniently positioned with mobile communication, but communication related costs including the price of the device and service charges become a big burden on the household. But the government does not seem to do the right role at the right time to prevent the market failure to maximize consumer welfare and social welfare through supporting fair competition. This principal-agent problem issues of mobile communication policies will be understood in perspective of public choice against joint use of the mobile communication network, number portability, separation of phone distribution and phone service, network neutrality, mobile phone subsidy since the early 1990s when mobile phone service was introduced in Korea.

• The Korean Journal of Financial Management
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• v.20 no.1
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• pp.61-92
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• 2003

As an extension of previous researches with the conclusion that the announcement of adopting stock options generates positive abnormal returns, this paper examined whether the abnormal return changes over time or varies depending on the number of stock options granted. Empirical analysis was made to find whether the announcement of stock option awards has the same response in the stock market from the early days when stock option plans had been introduced in the Korean stock market till today when it was widespread. Results indicate that the announcement effect had been on a gradual decline since 2000. In addition, it is found that if a company announces stock option awards several times, the abnormal return gradually declines in proportion of the number of stock options granted. This implies that as the stock option awards become widespread, the positive effect that the announcement of adopting stock options generates as news has been on a relatively steady decrease. In short, it leads to a conclusion that the more companies grant stock options, and the more stock options a company announces, the less impact it has on the increase in the firm's value.

• Journal of Labour Economics
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• v.23 no.2
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• pp.1-37
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• 2000

Since the early 1990s, the Korean courts have tilted in the direction of giving greater freedom to employers by relaxing the restrictions on dismissal for economic reasons. During the Korean economic crisis of 1998, the Korean Labor Standard Act was also revised for the purpose of relieving the limitation of employer's discretion in employment adjustment. From the Coasian perspective, this article analyze how implied contracts for the employee's reliance and employer's compliance might be influenced after the formal law is revised. We demonstrate that, if the legal change results in excessive intervention, it might cause the employers to over-breach, the employees to under-rely, and the accompanying efficiency to decrease. We scrutinize the total population of unjust dismissal cases since 1987 in order to investigate how the legal changes in Korea have affected the implied contracts. Our empirical analysis raises a possibility that Korean legal changes made in 1990s might have increased the employer's opportunism and decreased the employer's reliance effort.

• Journal of Technology Innovation
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• v.22 no.2
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• pp.157-183
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• 2014

This paper examines how the concentration of ownership in firms influences the R&D investment decision and whether the type of a firm's management (i.e, the owner-manager or professional manger) differentiates the relationship between the ownership concentration and R&D investments by using data of Korean pharmaceutical companies between 2004 and 2008. The results show that the share of the largest shareholder and R&D investment have an inverted U-shaped relationship, and whether a CEO is an owner or a professional manager affects the curvature of the inverted U-shaped relationship. Specifically, when a firm's CEO is a professional manager and the share of his stock is small, increase in the CEO's share increases the R&D investment in the larger amount than when a firm's CEO is an owner. This is because the increase in ownership reduces agency cost; However, when the share of his stock is large, the increase in CEO's share decreases R&D investment in the larger amount than when a firm's CEO is an owner. This is because a professional manager gets concerned over excessive risk exposure more than an owner-manager does.