• Journal of Korea Multimedia Society
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• v.23 no.8
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• pp.1088-1098
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• 2020

This paper proposes an obstacle avoidance method using a depth polar grid. Depth information is a crucial factor for determining the safe path for collision-free navigation of unmanned aerial vehicles (UAVs) as it can perceive the distance to the obstacles effectively. However, the existing depth-camera-based approaches for obstacle avoidance require computational y expensive path planning algorithms. We propose a simple navigation method using the polar-grid of the depth information obtained from the camera with narrow field-of-view(FOV). The effectiveness of the approach was validated by a series of experiments using software-in-the-loop simulation in a realistic outdoor environment. The experimental results show that the proposed approach successfully avoids obstacles using a single depth camera with limited FOV.

• Proceedings of the KIEE Conference
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• 1990.11a
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• pp.272-277
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• 1990

A soft switched matrix converter is proposed by adopting the zero voltage switching technique being used in some resonant pole inverters. High operating frequency with safe and efficient switching improves dynamic and spectral performances and simplifies protection logics and snubber networks. Further, it can be implemented using simple analog circuits, having similar transfer characteristics to those of the modern pulse width modulated matrix converters such as, maximum voltage transfer ratio and unity input displacement factor. Analyses, design and simulation results are presented to verify the operating principle.

• Proceedings of the Korea Concrete Institute Conference
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• 1999.10a
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• pp.15-218
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• 1999

Concrete is the most generous, universal main structural material. There is active study for processing quality, stable quality mangement. Especially, strength is basic factor of evaluating stability of concrete building. Regaining required strength and homogeneity is very important to get self-stability in building to evaluate another characteristic. Concrete strength is important to the quality management. But, result of hardened concrete's quality test is hardly reflected to works immediately. When required strength is not enough, it could bring out safe problem, economic and administrative cost. It is pointed out that problems from strength evaluation, so early evaluation of concrete quality is required. From the trend that accelerating high quality concrete development, improving the method of quality test and early evaluation measure is urgent project. Throughout this report, it is suggested the method with use of microwave to evaluate 28-days concrete strength.

• Fire Science and Engineering
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• v.15 no.3
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• pp.63-69
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• 2001

Applying a life safety concept to apartment design procedure is essential to protect people from unwanted fire. A Balcony design in apartment is a important egress safety factor because it provide means of safe egress and can limit a flame spread to adjacent space from fire source. Some design principles and details of balcony plan are suggested to improve egress safety level with analyzing broad case study.

• Journal of the Korean Society for Aviation and Aeronautics
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• v.28 no.3
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• pp.52-60
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• 2020

The purpose of this study was to analyze the effects of Student Majoring in Flight Operation's propensity, safety behavior and aeronautical decision-making. According to the analysis results, First, parents' criticism of perfectionism factor is found to have a negative effect on safety behavior. Second, student pilot's proactive personality has a positive impact on both safety participation behavior and safety compliance behavior. Third, both safety participation behavior and safety compliance behavior are found to have a significant effect on situation awareness, solution generation and solution implementation of decision making stages. Therefore, this study is intended to provide useful basic data that can be applied to studies such as appropriate psychological counseling, optimal training directions and teaching methods in order to cultivate excellent human resources through safe flight training.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.22 no.7
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• pp.602-605
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• 2009

The heat generation in the high-$T_c$ superconducting (HTS) wire is related with the cost efficiency and safe factor of HTS devices. This paper deals with the thermal quench at the conduction-cooled joint between HTS wire and copper terminals. The 3-D numerical simulation of thermal distributions in part of the copper terminals was implemented and the premature quench at copper block was observed through the test. The results will be helpful to design the conduction-cooled HTS magnets.

• Journal of the Korean Society for Aviation and Aeronautics
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• v.16 no.4
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• pp.35-40
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• 2008

There are many studies indicate that human is one of the major contributing factors to the aviation accident. To this end, the Human Factor of pilots and in flight operations has been a popular subject to be studied, however, not of the air traffic controllers. Recently, some States have started studying Human Errors in Air Traffic Control field, removal of the potential errors in advance and prevention of the similar errors. This study analyzed Human Errors in air traffic control in terms of LOSA of airlines, which has been actively studied. This study will contribute to safe Flight Operation and Air Traffic Control.

• IE interfaces
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• v.25 no.4
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• pp.422-430
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• 2012

In this article, we introduced the estimation method by 'Safety Integrity Level'(SIL) for the criterion of safety assurance and performed a case study on a flame scanner. SIL requires probabilistic evaluation of each set of equipment used to reduce risk in a safety related system. FMEDA(Failure Modes, Effects and Diagnostic Analysis) method is widely used to evaluate the safety levels and provides information on the failure rates and failure mode distributions necessary to calculate a diagnostic coverage factor for a part or a component. Basically, two parameters resulting from FMEDA are used for SIL classification of the device : SFF(Safe Failure Fraction) and PFD(Probability of Failure on Demand). In this case study, it is concluded that the flame scanner is designed to fulfill the condition of SIL 3 in the aspect of SFF and PFD.

• Architectural research
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• v.2 no.1
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• pp.27-34
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• 2000

Most research on high-rise housing has focused on low-income residences, and usually the psychological and social well-being of women and children. The validity of such findings are questionable for other populations since high-rise living has served other groups and their various needs in particular settings. Lack of knowledge and understanding about high-rises has represented an obstacle to the accurate representation of American urban reality in residential environments. The review of literature and factor analysis identified Important environmental factors. The survey was conducted in the selected downtown high-rise communities of major U.S. cities. Analyses revealed that there were unique characteristics of residents who prefer to live in this type of housing. It was also found that living in middle-income urban high-rise condominiums does not contribute significantly to the problems associated with high-rise living itself. Even though there were some deficiencies of social interaction and activities among residents, the middle-income condominiums were serving particular residents as maintenance-free and safe place imprinted by a positive image of sweet memories or sometimes by a window view presiding over downtown skyline.

• Journal of Navigation and Port Research
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• v.27 no.6
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• pp.611-618
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• 2003

It can be said that the relationship between the maneuvering ability of operators and the navigational environment affects the safe degree of navigation in the collision avoidance situation. In order to reduce the occurrence probability of accident and to maintain the safety, it is necessary to clarify the relationship between human behavior and navigational environment. In this study, therefore, we analyzed and discussed the relationship between the maneuvering characteristics and the safety focused on human behavior as a fundamental factor of marine accidents using ship handling simulator and questionnaire. As a result, we concluded that navigational environment changes variously and the maneuvering ability of operators also varies with the navigational environment, and the ship handling characteristics strongly affect the occurrence probability of accident.