• Journal of the Korean Society for Aviation and Aeronautics
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• v.22 no.4
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• pp.65-74
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• 2014

Unmanned aerial vehicles(UAVs) refer to the aircraft which carries no human pilot and is operated under remote control or in autonomous operational mode. As the UAVs can perform the dull, dangerous and difficult missions, various kinds of UAVs with different sizes and weights have been developed and operated for both civil and military application. As the avionics and communication technology related to the UAVs are matured, the demand for the UAVs is dramatically increased. Therefore, It is important to develope airworthiness process and regulations of the UAVs to minimize related risk to the man and environment. This paper describes related regulations and classification of the small UAVs for different international airworthiness authorities. The analysis of the CS-LURS verses Stanag 4702 and Stanag 4703 can provide guidelines for the generation of the airworthiness certification criteria for the small UAVs in civil sector. This paper conducted kinetic impact energy analysis of the loss of the small UAVs control scenarios and of the very small UAVs under 66 joules. Based on the analysis, the energy impact analysis can be considered before the design certification approval for the small UAVs.

• Industrial Engineering and Management Systems
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• v.9 no.2
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• pp.107-120
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• 2010

In today's uncertain economic environment, the evaluation of safety for investment alternatives is of practical importance in manufacturing companies. This paper examines a method of quantitatively evaluating profitability and risk for multiple alternatives using the total-cost unit-cost domain. The paper assumes such factors as unit sales price, sales and production volume, unit variable cost, fixed cost, and yield for each alternative. The paper incorporates the relationship between production capacity and demand, distinguishing between cases of production capacity surplus and shortage for each year over the entire planning horizon. The paper investigates the case in which the values of each factor independently move in the direction of decreasing profit each year, and clarifies the procedure of comparing safety among multiple investment alternatives on a single consolidated total-cost unit-cost domain. The difficulty of the problem lies in the method of consolidating multiple total-cost unit-cost domains into a single domain since the combination of years of capacity surplus and shortage depends upon the change values in each factor under consideration. A systematic method of evaluating profitability as well as risk is presented, and the validity of the proposed method is verified using a numerical example.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.29 no.2
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• pp.226-235
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• 2019

Objectives: The purpose of this study was to investigate whether there were differences in manufacturing industry worker's health issues depending on job stress, fatigue, and health and safety services. Methods: The purpose of the questionnaire survey and its contents were explained to manufacturing industry health personnel, and the questionnaires were collected from 666 workers from 17 manufacturing workplaces. Questionnaires with missing data were excluded from the analysis so a total of 632 questionnaires were included. Results: Overall, 74.1% of the respondents had experienced health issues during the preceding month. The factors affecting worker health were number of workers(OR=1.000034, p=.013), job demand(OR=1.82, p=.009), MFS(OR=1.85, p=.003), provision of safety & health information(OR=1.85, p=.048), wearing protector(OR=2.58, p=.021). Conclusion: It is necessary to strengthen the safety and health education to mitigate hazardous and risk factors. Employers should provide health managers in charge of safety and health education to control workplace risk factors. In case of small businesses, it may be necessary to strengthen safety and health education in existing worker health centers and government support projects.

• The Journal of Asian Finance, Economics and Business
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• v.9 no.6
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• pp.69-79
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• 2022

The purpose of the study is to look into the likelihood of private sector enterprises going bankrupt due to COVID-19 pandemic-related issues. The data for this study was taken from the World Bank's Enterprise Survey, which was intended to assess the impact of the COVID-19 pandemic on the business sector. This study uses the Ordinal Logit Method to analyze the model with dependent variables having ordinal values. The determinants reflect business performance, innovation, business relationships, and government support. According to the estimation results, a lower probability of business closures, illiquidity, and payment delays are found in businesses that maintain sales growth, operating hours, temporary workers, product portfolio, consumer demand, and input supply. Meanwhile, the increase in online business activities and receiving support from financial institutions and the government do not help businesses reduce the risk. Moreover, higher survival is found in manufacturing and developing countries. This implies the fragility of businesses in the retail and service sectors, especially for mega-enterprises in developed countries. In addition, the negative impact of the COVID-19 pandemic on businesses in Europe and West Asia is less severe than in other regions. The results imply policies to support the private sector during the pandemic, such as increasing labor market flexibility or rapidly implementing supportive policies.

• Journal of Korea Multimedia Society
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• v.25 no.3
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• pp.510-518
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• 2022

This paper confirmed the technical reliability of mobile-based sarcopenia prediction and monitoring system. In implementing the developed system, we designed using only sensors built into a smartphone without a separate external device. The prediction system predicts the possibility of sarcopenia without visiting a hospital by performing the SARC-F survey, the 5-time chair stand test, and the rapid tapping test. The Monitoring system tracks and analyzes the average walking speed in daily life to quickly detect the risk of sarcopenia. Through this, it is possible to rapid detection of undiagnosed risk of undiagnosed sarcopenia and initiate appropriate medical treatment. Through prediction and monitoring system, the user may predict and manage sarcopenia, and the developed system can have a positive effect on reducing medical demand and reducing medical costs. In addition, collected data is useful for the patient-doctor communication. Furthermore, the collected data can be used for learning data of artificial intelligence, contributing to medical artificial intelligence and e-health industry.

• KDI Journal of Economic Policy
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• v.44 no.2
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• pp.1-28
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• 2022

This paper studies how COVID-19 has affected the labor market in Korea through a general equilibrium model with multiple industries and occupations. In the model, workers are allocated to one of many occupations in an industry, and industrial or occupational shocks alter the employment structure. I calibrate the model with Korean data and identify industrial and occupational shocks, referred to here as COVID-19 shocks, behind the employment dynamics in 2020 and 2021. I find that COVID-19 shocks are more severe for those with jobs with a higher risk of infection and in those that are more difficult to do from home. Interestingly, the relationship between COVID-19 shocks and infection risk weakened as the pandemic progressed, whereas the relationship between COVID-19 shocks and easiness of work-from-home strengthened. I interpret the results as meaning that the pandemic may direct future technological changes to replace tasks that require contact-intensive steps, and I simulate the impact of such technological changes through the lens of the model. The results show that such technological changes will lower the demand for manual workers compared to the demands for other occupations. This contrasts with the earlier trend of job polarization, where manual workers continued to increase their employment share, with the share of routine workers secularly declining at the same time.

• International conference on construction engineering and project management
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• 2007.03a
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• pp.509-519
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• 2007

Private financing is playing an increasing role in public infrastructure construction projects worldwide. However, private investors/operators are exposed to the financial risk of low profitability due to the inaccurate estimation of facility demand, operation income, maintenance costs, etc. From the operator's perspective, a sound and thorough financial feasibility study is required to establish the appropriate capital structure of a project. Operators tend to reduce the equity amount to minimize the level of risk exposure, while creditors persist to raise it, in an attempt to secure a sufficient level of financial involvement from the operators. Therefore, it is important for creditors and operators to reach an agreement for a balanced capital structure that synthetically considers both profitability and repayment capacity. This paper presents an optimal capital structure model for successful private infrastructure investment. This model finds the optimized point where the profitability is balanced with the repayment capacity, with the use of the concept of utility function and multi-objective GA (Generic Algorithm)-based optimization. A case study is presented to show the validity of the model and its verification. The research conclusions provide a proper capital structure for privately-financed infrastructure projects through a proposed multi-objective model.

• Journal of the Korean Society for Aviation and Aeronautics
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• v.31 no.1
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• pp.43-56
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• 2023

The aviation industry has continued to grow despite the influence of external environmental factors such as SARS and MERS. However, this growth has led to a sharp decrease in air traffic and a crisis of flight suspension due to the collapse of the global value chain and the decline of the world economy as the World Health Organization (WHO) declared a COVID-19 pandemic. Due to the decrease in the number of international flights, aviation workers such as pilots and cabin crew were exposed to high psychological stress and fatigue, such as large-scale layoffs, job instability, decrease in income, and increased risk of infection during. Recently, the international community has eased immigration restrictions through quarantine activities, and airlines are taking a step further to recover existing air demand. However, during the crisis period, a significant number of professional workers have been turned off or fired, and the physical and mental fatigue of those who can perform their duties is increasing. Therefore, this paper intends to examine the direction of policy improvement and the identification of problems in aviation safety and fatigue management after the pandemic.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2022.11a
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• pp.145-146
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• 2022

The demand for a construction method capable of securing a safety environment and improving quality is increasing. There is a high risk of falling when working at a high place in an environment where it is difficult to secure visibility, such as an underground space, and there is a risk of falling if cement liquid waterproof materials are transferred to the top of the scaffold by manpower. In addition, when working on a high place in a poor environment, the quality uniformity of the upper part of the wall is deteriorated. In addition, as waterproof technicians gradually age and decrease, it is difficult to secure them, so it is urgent to prepare countermeasures against the shortage of waterproof technicians. Therefore, the purpose of this study is to develop cement liquid waterproof spouting construction equipment that can secure uniform quality of construction areas to prevent accidents and ensure safety of workers, improve work efficiency and quality due to improvement of work environment. The adhesion performance of the cement liquid waterproof material could be improved by about 20% in accordance with the use of the equipment.

• International conference on construction engineering and project management
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• 2011.02a
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• pp.474-479
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• 2011

With Beijing's success in bidding for the 2008 Olympic Games, the increasing demand for infrastructure development and reduced public sector funding capacity has created a significant funding gap which calls for alternative project delivery methods such as Public-Private Partnership (PPP). Although the exploration of infrastructure projects using PPP model have been practiced since the late 80s, the $560 million National Stadium which served as the main venue for the Olympic Games is the first stadium project in China to be delivered under PPP operation. The project is generally considered successful despite the concession transfer in 2009 with concern of better serving the public interest. Compared to other infrastructure projects such as transportation, waste management and water management, the development of major sports facilities for mega-sports events with PPP has its own unique features and is subject to different major risks. This research identifies and analyzes critical risks in the implementation of PPP in major sports facility development through case study of the National Stadium project. A questionnaire survey and several interviews are conducted to solicit expert opinions from experienced practitioners. The purpose is to provide additional insights in risk management strategies and opportunities in China's PPP implementations in major sports facilities for policy makers and private sectors involved with investment decisions in future similar infrastructure development.