• The Korean Journal of Applied Statistics
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• v.29 no.4
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• pp.741-752
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• 2016

Numerous studies have shown that normal inverse Gaussian (NIG) distribution adequately fits the empirical return distribution of financial securities. The estimation of parameters can also be done relatively easily, which makes the NIG distribution more useful in financial markets. The maximum likelihood estimation and the method of moments estimation are easy to implement; however, we may encounter a problem in practice when a relationship among the moments is violated. In this paper, we investigate this problem in the parameter estimation and try to find a simple solution through simulations. We examine the effect of our adjusted estimation method with real data: daily log returns of KOSPI, S&P500, FTSE and HANG SENG. We also checked the performance of our method by computing the value at risk of daily log return data. The results show that our method improves the stability of parameter estimation, while it retains a comparable performance in goodness-of-fit.

• Smart Media Journal
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• v.7 no.3
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• pp.64-71
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• 2018

Utilization of unmanned aerial vehicles (UAVs) are rapidly expanding to various fields ranging from defense, industry, entertainment and personal hobbies. Due to the increased activities of unmanned airplanes, many security problems have emerged, including flight path errors to undesired destinations, secondary threats due to exposed securities caused by the capture of unmanned airplanes in hostile countries. In this paper, we find security vulnerabilities in UAVs such as GPS spoofing, hacking captured video information, malfunction due to signal attenuation through jamming, and exposure of personal information due to image shooting. In order to solve this problem, the stability of the unstructured data is secured by setting the encryption of the video shooting information section using the virtual private network (VPN) to prevent the GPS spoofing attack. In addition, data integrity was ensured by applying personal information encryption and masking techniques to minimize the secondary damage caused by exposure of the UAV and to secure safety. It is expected that it will contribute to the safe use and stimulation of industry in the application field of UAV currently growing.

• Industry Promotion Research
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• v.4 no.2
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• pp.39-52
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• 2019

Thus, this study suggests following solutions to youth suicides in South Korea. First, we need to help adolescents to establish their identities based on the traditional ethical principles from both eastern and western cultures. Second, we claim that improvement of educational environment is urgently needed. Adolescents' emotional securities need to be well supported through stabilized family lives and we need to set expanded communication system between students and the school education system to help teenagers lead happier and more active school lives. Lastly, this study suggests establishing a social security system by eliminating potential risk factors and extending the protection factors so that Korean adolescents do not hesitate asking for help to protect themselves when they feel suicidal.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.42 no.3
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• pp.131-141
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• 2019

Recently the business environment surrounding the financial investment industry is changing rapidly, and the demands of customers (diversity and the cycle of change etc.) are getting shorter. In this context, it can be said that companies are forced to adopt an agile management environment. In particular, non-face-to-face channels, including MTS, is adopting the agile system into the digital finance sector from a company-wide and strategic perspective. This study analyzed the effects of MTS services' environment quality on customer satisfaction and continuous intention to use for MTS users who are rapidly increasing under the agile management environment in the financial investment industry. This study surveyed the quality of service environment (accessibility, convenience, design, security), customer satisfaction, and continuous intention to use for 350 MTS users. First, accessibility, convenience, and security of MTS service environment quality had a positive effect on customer satisfaction, and design was rejected Second, customer satisfaction has a positive effect on continuous intention to use. Third, convenience and security of MTS service environment quality have positive effects on continuous intention to use, and accessibility and design were rejected. The results of this study, together with demographic analysis, are expected to provide useful implications for MTS activation studies and securities firms' strategies.

• Journal of the Korea Convergence Society
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• v.10 no.9
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• pp.199-207
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• 2019

This study aims to analyze the profitability of Robo-Advisors portfolio combined with the analysts' forecasts on the Korean stock prices. Sample stocks are 8 blue-chips and sample period is from 2003 to 2019. Robo-Advisor portfolio was suggested using the Black-Litterman model combined with the analysts' forecasts and its profitability was analyzed. Empirical result showed the suggested Robo-Advisor algorithm produced 1% annual excess return more than that of the benchmark. The study documented that the analysts' forecasts had an economic value when applied in the Robo-Advisor portfolio despite the prevalent blames from investors. The profitability on small or medium-sized stocks will need to be analyzed in the Robo-Advisor context because their information is relatively less known to investors and as such is expected to be strongly influenced by the analysts' forecasts.

• Asia-Pacific Journal of Business
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• v.11 no.3
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• pp.123-136
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• 2020

Purpose - This study is to verify the impact of the documentation of key audit matters on the value relevance of accounting information in accordance with the revised accounting audit standards in 2017. Investors will be able to identify the company's significant financial risks through key audit matters and use them to make investment decisions. Design/methodology/approach - From 2011 to 2019, the final sample is 290, based on the December settlement of accounts listed on the securities market. Ohlson (1995) was used to verify the incremental link between net income and the book value as a determinant of corporate value. Findings - First, the key audit matters in the financial industry was found to have a negative (-) effect that was significant to the value relevance of accounting Information. In addition, the value of the interaction between the key audit matters and the net income is a significant (+) relationship with the share price and the value of the interaction between the key audit matters and the book value is a significant (-) relationship with the share price. This means that the key audit matters is the determining factor of corporate value, positively reflects the accounting information in net income and negatively reflects the accounting information in book value. Second, among the key audit matters, the fair value assessment of financial instruments and the adequacy of premiums reserve have a significant impact on the value relevance of accounting information. Research implications or Originality - The results of this study suggest that investors recognize key audit matters as information about the company's major financial risks and reflect them differently in the value relevance of accounting information.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.25 no.10
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• pp.1353-1358
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• 2021

IoT (Internet of Things) emerges from various technologies such as communications, micro processors and embedded system and so on. The IoT has also been used to UAV (Unmanned Aerial Vehicle) system. In manned aircraft, a pilot and co-pilot should control FCS (Flight Control System) with FBW(Fly By Wire) system for flight operation. In contrast, the flight operation in UAV system is remotely and fully managed by GCS (Ground Control System) almost in real time. To make it possible the communication channel should be necessary between the UAV and the GCS. There are many protocols between two systems. Amongst them, MAVLink (Macro Air Vehicle Link) protocol is representatively used due to its open architecture. MAVLink does not define any securities itself, which results in high vulnerability from external attacks. This paper proposes the method to enhance data security in GCS network by applying cryptographic methods to the MAVLink messages in order to support safe UAV operations.

• The Journal of Industrial Distribution & Business
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• v.11 no.12
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• pp.39-45
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• 2020

Purpose: The stock price delay phenomenon refers to a phenomenon in which stock prices do not immediately reflect corporate information and the reflection is delayed. A prior study reported that the stock price delay phenomenon appears strongly when the quality of corporate information is low (Callen, Khan, & Lu, 2013). The purpose of the internal accounting control system is to improve the reliability of accounting information. Specifically, the more professionals such as certified public accountants are placed in the internal accounting control system, the more information is prevented from being distorted, so the occurrence of stock price delay will decrease. Research design, data and methodology: In this study, companies listed on the securities market from 2012 to 2016 were selected as a sample to analyze whether the stock price delay phenomenon is alleviated as accounting experts are assigned to the internal accounting control system. The internal control personnel data were collected in the "Internal Accounting Control System Operation Report" attached to the business report of each company of the Financial Supervisory Service's Electronic Disclosure System(DART). The measurement method of the stock price delay phenomenon was referred to the study of Hou and Moskowitz (2005). The final sample used in the study is 2,641 firm-years. Results: It was found that companies with certified accountants in the internal accounting control system alleviate the stock price delay phenomenon. This result can be interpreted as increasing the speed at which corporate information is reflected in the stock price by improving the reliability of information disclosed in the market by the placement of experts in the system. Conclusions: The results of this study suggest that accounting professionals assigned to the internal accounting control system are playing a positive role in providing high-quality information to the market. In this study, focusing on the fact that the speed at which corporate information is reflected in the stock price is very important for the stakeholders in the capital market, we find that having a certified public accountant in the internal accounting control system alleviates the stock price delay phenomenon.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.16 no.5
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• pp.79-92
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• 2006

Computer virus is one of the most common information security problems in the information age. This study investigates the difference of users' perception of security elements between large companies and small-and-medium companies on the subject of computer virus. Based on t-test, no significant difference is found in users' perception on security threat and security risk While users satisfy with the level of security policy, there is a significant difference on the level of security policy recognition between the two sizes of companies. Moreover, there are significant differences on information assets, security vulnerability and security effectiveness, which implies difference in the users' perception on importance of assets, exposure to threats and computer virus prevention efforts between large and small-and-medium companies.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.22 no.3
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• pp.553-564
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• 2012

Today's security initiatives tend to integrate the physical and information securities which have been run by completely separate departments. That is, the converged security management becomes the core in the security market trend. However, to the best of our knowledge, we cannot find any solutions how to combine these two security events for the converged security. In this paper, we propose an information security object-driven approach which utilizes the physical security events to enhance and improve the information security. For scalability, we also present a systematic method using the analytic hierarchy process finding the meaningful event combinations among the large number of physical security events. In particular, we show the whole implementation processes in detail where we consider the information security object 'illegal computing system access' combined with two physical security devices - access controller and CCTV+video analyzer system.