• Journal of Korean Society of Industrial and Systems Engineering
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• v.18 no.36
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• pp.365-370
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• 1995

In recent years, there have been attempts to explain firms' capital structure based upon the agency theory which considers agency problems arising due to ownership structure. Agency theory starts from the coctractual relationship (explicit or implicit) between principals and agents. Since uncertainty exists in real world and information is distributed asymmetrically, there are conflicts between principals and agents. The objectives of this study are to analyze, based upon agency theory, factors which are expected to affect firms' capital structure and to test empirically the relevance of agency cost hypothesis about the determination of capital structure, For these purposes, this paper carried out multiple regression in order to examine whether the factors of agency costs affect significantly the determination of capital structure. The results of empirical analysis are summarrized as follows; First, insider-equity ration has been negatively correlated with capital structure. Second, growth opportunity variabless has been insignificant coefficients with capital structure.

• Safety and Health at Work
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• v.6 no.2
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• pp.128-133
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• 2015

Background: To investigate the relationship between musculoskeletal disorders and comorbid health problems, including depression/anxiety disorder, insomnia/sleep disorder, fatigue, and injury by accident, and to determine whether certain physical and psychological factors reduce comorbid health problems. Methods: In total, 29,711 employees were selected from respondents of the Third Korean Working Conditions Survey and categorized into two groups: Musculoskeletal Complaints or Musculoskeletal Sickness Absence. Four self-reported health indicators (overall fatigue, depression/anxiety, insomnia/sleep disorder, and injury by accident) were selected as outcomes, based on their high prevalence in Korea. We used multiple logistic regression analysis to determine the relationship between comorbid health problems, musculoskeletal complaints, and sickness absence. Results: The prevalence of musculoskeletal complaints and musculoskeletal sickness absence due to muscular pain was 32.26% and 0.59%, respectively. Compared to the reference group, depression/anxiety disorder and overall fatigue were 5.2-6.1 times more prevalent in the Musculoskeletal Complaints Group and insomnia/sleep disorder and injury by accident were 7.6-11.0 times more prevalent in the Sickness Absence Group. When adjusted for individual and work-related physical factors, prevalence of all four comorbid health problems were slightly decreased in both groups. Conclusion: Increases in overall fatigue and depression/anxiety disorder were observed in the Musculoskeletal Complaints Group, while increases in insomnia/sleep disorder and injury by accident were observed in the Sickness Absence Group. For management of musculoskeletal complaints and sickness absence in the workplace, differences in health problems between employees with musculoskeletal complaints and those with sickness absence as well as the physical and psychological risk factors should be considered.

• Proceedings of the IEEK Conference
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• 2008.06a
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• pp.127-128
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• 2008

Research and development status of Dog-Horse robot is presented based on the critical technology issues which generates severe problems or hard trade-offs to meet the general requirement of system and new technologies. This paper covers from architectural problems to specific technology to overcome the operational requirement. Technology development based on operation requirement derived new research challenges as well as advanced development for system adaptation.

• International Journal of Naval Architecture and Ocean Engineering
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• v.7 no.1
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• pp.128-141
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• 2015

Independent Component Analysis (ICA), one of the blind source separation methods, can be applied for extracting unknown source signals only from received signals. This is accomplished by finding statistical independence of signal mixtures and has been successfully applied to myriad fields such as medical science, image processing, and numerous others. Nevertheless, there are inherent problems that have been reported when using this technique: instability and invalid ordering of separated signals, particularly when using a conventional ICA technique in vibratory source signal identification of complex structures. In this study, a simple iterative algorithm of the conventional ICA has been proposed to mitigate these problems. The proposed method to extract more stable source signals having valid order includes an iterative and reordering process of extracted mixing matrix to reconstruct finally converged source signals, referring to the magnitudes of correlation coefficients between the intermediately separated signals and the signals measured on or nearby sources. In order to review the problems of the conventional ICA technique and to validate the proposed method, numerical analyses have been carried out for a virtual response model and a 30 m class submarine model. Moreover, in order to investigate applicability of the proposed method to real problem of complex structure, an experiment has been carried out for a scaled submarine mockup. The results show that the proposed method could resolve the inherent problems of a conventional ICA technique.

• Safety and Health at Work
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• v.10 no.1
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• pp.125-129
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• 2019

The ultimate goal of the quality control program for special periodic health examination agencies is to diagnose the health condition of a worker correctly, based on accurate examination and analysis skills, leading to protect the worker's health. The quality control program on three areas, chemical analysis for biological monitoring since 1995, and pneumoconiosis, audiometric testing since 1996, has contributed to improve the reliability of occupational health screenings by improving the issues including standardization of testing methods, tools, diagnostic opinions, and reliability of analysis for biological monitoring. It has contributed to improving the reliability of occupational health monitoring by rectifying the following issues associated with previous monitoring: absence of standardized testing methods, testing tools that are not upgraded, mismatching diagnostic opinions, and unreliable results of biological specimen analysis. Nevertheless, there are issues in need of further improvement such as lack of expertise or the use of inappropriate method for health examination, and passive and unwilling participation in the quality control. We suggested solutions to these problems for each area of quality control program. Above all, it is essential to provide active support for health examiners to develop their expertise, while encouraging all the health screening agencies, employers, and workers to develop the desire to improve the system and to maintain the relevance.

• Journal of the Korea Institute of Military Science and Technology
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• v.7 no.4 s.19
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• pp.26-35
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• 2004

The ASTP is the standard of the assessment ASRP that is monitoring the performance, reliability and safety characteristics of the ammunition items. The ASTP used in domestic now has applied to US Army's grade system and grading criteria so that it cause some problems. To resolve these problems of ASTP, we surveyed both the quality level of production and the field management of ammunition, which compared with grade system and classification criteria. As a result of study, we changed grade system from four steps to three steps and applied the Korean Military Specifications and the Malfunction Criteria to the classification criteria of grades. We are looking forward to improving the reliability and effectiveness of ASRP assessment by simplifying grade system and generalizing grading criteria of ASTP.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.8 no.3
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• pp.63-78
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• 1998

Recently, to use the evaluated firewall is recognized as a solution to achieve the security and reliability for government and organizarions in Korea. Results of firewall evaluation using ITSEC(Information Technology Security Evaluation Criteria) and CCPP(Common Criteria Protection Peofile)have been announced. Because there are problems to apply ITSECor CCPP for the firewall evaluation in korea environment, korea government and korea Information security Agency (KISA) decided to develop our own security dvaluation critrtia fir firewalls.As a result of the efforts, Korea firewall security evaluation criteria has been published on Feb. 1998. In this paper, we introduce Korea security evaluation criteria for firewalls. The ceiteria consists of functional and assurance requirements that are compatible with CC Evaluation Assurance Levels(EALs)

• Journal of Preventive Medicine and Public Health
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• v.57 no.4
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• pp.379-387
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• 2024

Objectives: Mental health issues have become a growing concern worldwide. Research has shown that regular physical activity (PA) can positively affect mental health. This study investigated the associations between PA and mental health problems (MHPs) in middle-aged Indonesians. Methods: The study utilized data from the 2018 Indonesian Basic Health Research Survey and used a cross-sectional approach. The participants included individuals aged 40-60 years who completed the 20-question Self-Reporting Questionnaire. A logistic regression was performed to analyze a sample of 263 930 data points. Results: Nearly 10.4% of the participants suffered from mental health issues. Notably, among those who did not engage in moderate and vigorous PA, a sign of MHPs was found in 12.5% of participants. Those who met World Health Organization standards for PA were less likely to experience MHPs (10.1%). This study found a significant association between PA and mental health. After adjusting for smoking, alcohol consumption, non-communicable diseases, and socio-demographic variables like age, sex, education, occupation, marital status, and residence, the connection between PA and mental health became even stronger (adjusted odds ratio, 0.81; 95% confidence interval, 0.78 to 0.85; p<0.001). Conclusions: Regular PA has been shown to affect mental health positively. Therefore, it is important to improve health education and efforts to raise awareness among middle-aged Indonesians about the importance of PA in maintaining good mental health.

• International Journal of Control, Automation, and Systems
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• v.3 no.2
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• pp.217-224
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• 2005

Generally, the underwater flight vehicle (UFV) depth control system operates with the following problems: it is a multi-input multi-output (MIMO) system because the UFV contains both pitch and depth angle variables as well as multiple control planes, it requires robustness because of the possibility that it may encounter uncertainties such as parameter variations and disturbances, it requires a continuous control input because the system that has reduced power consumption and acoustic noise is more practical, and further, it has the speed dependency of controller parameters because the control forces of control planes depend on the operating speed. To solve these problems, an adaptive fuzzy sliding mode controller (AFSMC), which is based on the decomposition method using expert knowledge in the UFV depth control and utilizes a fuzzy basis function expansion (FBFE) and a proportional integral augmented sliding signal, is proposed. To verify the performance of the AFSMC, UFV depth control is performed. Simulation results show that the AFSMC solves all problems experienced in the UFV depth control system online.

• Journal of Information Technology Services
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• v.18 no.5
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• pp.53-70
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• 2019

As information security becomes more important as the fourth industrial revolution gradually emerges, an efficient and effective way to find vulnerabilities in information systems is becoming an essential requirement of information security. As the point of the protection of current information and the protection of the future industry, the Korean government has paid attention to the bug bounty, which has been recognized for its efficiency and effectiveness and has implemented through the Korea Internet Security Agency's S/W vulnerability bug bounty program. However, there are growing problems about the S/W vulnerability bug bounty program of the Korea Internet Security Agency, which has been operating for about 7 years. The purpose of this study is to identify the problems in Korean bug bounty policies through the characteristics of the bug bounty program, and to suggest the direction of the government's policy to activate the bug bounty like changes in the government's approach utilizing the market.