• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.49 no.2
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• pp.107-120
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• 2021

Electric-powered distributed propulsion aircraft possess a complex wake flow and mutual interference with the airframe, due to the use of many propellers. Accordingly, in the early design stage, rapid aerodynamic and load analysis considering the effect of propellers for various configurations and flight conditions are required. In this study, an efficient panel-based aerodynamic analysis method that can take into account the propeller effects is developed and validated. The induced velocity field in the region of propeller wake is calculated based on Actuator Disk Theory (ADT) and is considered as the boundary condition at the vehicle's surface in the three-dimensional steady source-doublet panel method. Analyses are carried out by selecting an isolated propeller of the Korea Aerospace Research Institute (KARI)'s Quad Tilt Propeller (QTP) aircraft and the propeller-wing configuration of the former experimental study as benchmark problems. Through comparisons with the results of computational fluid dynamics (CFD) based on actuator methods, the wake velocity of propeller and the changes in the aerodynamic load distribution of the wing due to the propeller operation are validated. The method is applied to the analysis of the Optional Piloted Personal Aerial Vehicle (OPPAV) and QTP, and the practicality and validity of the method are confirmed through comparison and analysis of the computational time and results with CFD.

• Trans-
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• v.11
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• pp.119-142
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• 2021

Video was a cultural practice based on image. The audience longs to experience new things, not everyday things through by video images. There are many components of the image, but among them, color, a visual representation, plays a big role. Since the advent of color films, color has constantly evolved as an important component of visual art and has become an important role in innovative visual art design. According to film history data, filmmakers were interested in color since the film was created in 1895, but in the early stages of film development, film colors were only black and white. Because these two colors no longer satisfy viewers, more natural colors began to emerge from the film as it was colored. However, with the development of historical paintings, the lack of artistic creation and the public's level increased, making people more active in using colors because simple reproduction of natural colors alone does not satisfy people. The colors in the video are both techniques of expression and can be understood by mind and thought. It is also an indication that colors do not just exist, but they work strongly on human psychology. Now people are so motivated by repetitive and unimportant information that they find that the human intuitive system simplifies the information they receive unconsciously that they have certain customs and characteristics when they see things. Color is part of the film language, or color language can express the film's ideological themes or portray vivid characters in the film, and people are receiving more intuitive messages. This study analyzed the basic color components of bisexual lighting, namely, pink, blue, and purple, and analyzed how human psychology is affected through color, combining the scenes from the video. The purpose of this paper is to explore what color language bisexual lighting is expressed using color properties in images and how bisexual lighting interacts with human psychology through color.

• Journal of the Korean GEO-environmental Society
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• v.12 no.12
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• pp.79-88
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• 2011

Adfreeze bond strength develops upon freezing of pore water within soil and at foundation surface. It has been reported that various factors like temperature, soil type, and pile surface roughness affect adfreeze bond strength. Especially, pile surface roughness has been considered as a primary factor to design pile foundation in frozen ground. It has usually been estimated with fixed correction factors for pile materials. However, even if the pile foundation material is the same, the surface roughness could vary depending on the production circumstances. In this study, laboratory test was carried out to quantitatively analyze the effects of surface roughness on the adfreeze bond strength, and fractal dimension was used as a measure for surface roughness. Test results showed that adfreeze bond strength increased with decreasing temperature, increasing vertical stress and surface roughness. The adfreeze bond strength varies sensitively with surface roughness in the early freezing section of $-2^{\circ}C$, but its sensitivity decreased in the temperature ranging between $-2^{\circ}C$ to $-5^{\circ}C$. The results conclude that the roughness highly affects the frictional resistance of pile surface in frozen ground; however, the roughness does not affect considerably when the temperature drops below about $-2^{\circ}C$.

• The Journal of the Korea Contents Association
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• v.21 no.6
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• pp.295-305
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• 2021

This paper attempted to explore the basic concept of a website for start-up supports angled towards North Korean defector entrepreneurs. The position of this study was made clear by reviewing the existing literature, and the case study was carried out to make sure the results are essential to create the services vital for the North Korean defector's entrepreneurial ecosystem. Focusing on the fact that there is not yet a website for supporting North Korean defectors' start-up in Korea, an early version named "Prometheus" was designed. A revised version called "Pathfinder" followed with improvements. This study conducted academic and practical experiments by directly designing and implementing a medium that can boost the development of the start-up ecosystem of North Korean defectors based on the insights provided by North Korean (future)business owners and South Koreans interested in the start-up ecosystem of North Korean defectors. Taking this study as an opportunity both the research to further clarify the "start-up of North Korean defectors," a very special phenomenon that exist in Korea, and the research for practical contribution should be encouraged in various ways. These efforts will not only help North Korean defectors start-up businesses, and also play a role in boosting a sense of coexistence and cooperation within North Korean defectors community.

• The Journal of Korea Institute of Information, Electronics, and Communication Technology
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• v.13 no.6
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• pp.496-502
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• 2020

The electronic attendance management system is being introduced and operated on a pilot basis by some universities and educational institutions. However, most of the related systems have installed and operated the existing barcode and magnetic card systems. Classroom attendance is managed by introducing RF cards, but it causes problems such as recognition distance (less than 5cm) and the need for a check process in which students have to read the card each time with a reader for attendance. Also, it is not possible to respond in real time to the situation of midterm (early leave, absence from the second lecture time, etc.) because it is used in the lecture time of one subject with the record checked once. In order to solve these problems, the various mobile attendance systems proposed to solve these problems are also unable to fundamentally solve problems such as interim attendance and proxy attendance because they check attendance using only the application of a smartphone. In this paper, we use geofencing technology, which is a positioning-based technology that detects the entry and exit of people, objects, etc. in areas separated by virtual boundaries. The proposed system solves the problem of intermediate attendance and alternate attendance by setting the student to automatically record the access record when entering and leaving the classroom set as a geofence with a smartphone. In addition, it also provides a function to prevent unintentional mistakes that occur through the smartphone by limiting some of the functions of the smartphone such as silence, vibration, and Internet use when entering the classroom.

• The Journal of Korea Institute of Information, Electronics, and Communication Technology
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• v.13 no.6
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• pp.556-561
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• 2020

The aging and declining agricultural population in the modern society requires improvement of the agricultural environment and is one of the representative problems. And since most of the work systems always require a transport work, the ratio of labor consumed in the transport work is very high. Accordingly, many types of transport vehicles are being developed and sold, and in the early days, most of them are powered transport vehicles using fossil fuels. However, it is paying attention to next-generation eco-friendly energy such as hydrogen, fuel cells, solar power, and bio due to the strengthening of international environmental regulations such as global warming and the Convention on Climate Change and the depletion of fossil fuels. Therefore, in this study, the ultimate goal is to develop an eco-friendly, easy-to-operate, safe agricultural electric vehicle that replaces fossil fuels. It was designed with a focus on controlling a wide range of vehicle speeds and securing stability of electric agricultural vehicles. Considering the performance and design, it is composed of a frame, a driving part, a steering part, and a controller system, and we are going to review and manufacture each part. It is believed that the manufactured electric vehicle for agriculture can be easily and conveniently operated in an agricultural society where young manpower is scarce, and can be helpful to the agricultural society through high efficiency.

• Journal of Christian Education in Korea
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• v.64
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• pp.347-368
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• 2020

The purpose of this study was explored the effect of Flipped PBL on Communication and Problem Solving skill of University students. For study, students in the college of education at A University and S University located in Gyeonggi-do were set up 60 students. They majored in Christian education and early childhood education, and the level of education was similar in the same region and department. In the experiment, the comparison group and the experimental group were separated, and data were collected through pre-test before class and post-test after class, followed by analysis covariance(ANCOVA). Between the comparative group performing flipped learning and the experimental group performing flipped PBL, the problem solving ability and communication ability using the flipped PBL averaged 4.28 and the communication ability averaged 4.06. As a result, it was higher than each of the comparison groups, confirming that it had a significant effect. This will be able to present a flipped PBL class design as an alternative method to overcome the limitations of the existing flip learning in a changing classroom situation and to improve the communication and problem solving ability of the learner.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.50 no.7
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• pp.507-514
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• 2022

The EO/IR targeting pod mounted on a fighter to acquire information about tactical targets is typically mounted and operated at the bottom of the aircraft fuselage. Since the aircraft equipped with such an external attachment has complexed aerodynamic and inertial characteristics compared to the aircraft flying without an external attachment, a method of system performance analyses is required to identify development risk factors in the early stages of development and reflect them in the design. In this study, a development plan was presented to provide the necessary modeling and simulation tools to develop a pod that can acquire measurement data stably in a highly maneuverable environment. The limiting operating conditions of the pods mounted on the highly maneuverable aircraft were derived, the aerodynamics and inertial loads of the mounted pods were analyzed according to the limiting operating conditions, and a flight data generation and transmission system were developed by simulating the mission of the aircraft equipped with the mounted pods.

• The Journal of the Convergence on Culture Technology
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• v.7 no.4
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• pp.791-800
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• 2021

British housing types began with detached houses using wood based on early Germanic cultures, and gradually divided into multi-story houses such as terraces houses, with the influx of houses using stone from Latin cultures influenced by France. Today, various types of housing types such as detached houses, townhouses, and apartments are mixed, and their origins can be found in housing types that have continued from the past. Housing types existing in the UK continue their context through this historical development process, but housing types in the UK also have been combined with those of other cultures, leading to modern housing types. In this paper, we examine the process of the UK's peculiar development of housing types superimposed with the recurring motion to the traditional European urban structures prior to the industrial revolution during contemporary years, and perimeter block collective housings of today; then, we study the process of applying the UK case as a concept of practical design and planning in order to continuously consider Korea's modern urban structure and corresponding types of housing. Through this process, we explore the identity of the housing type in Korea, which is pursuing fundamental changes in residential culture beyond quantitative housing supply in the process of rapid urbanization.

• Journal of Navigation and Port Research
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• v.46 no.3
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• pp.203-208
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• 2022

Recently, various digital technology issues such as e-Navigation, Maritime Autonomous Surface Ship (MASS) and Smart ships have constantly emerged in the maritime industry, based on the fourth industrial revolution. The International Maritime Organization is gradually tightening regulations for marine safety and marine environmental protection, and these strengthened regulations are leading to new maritime industries. Thus, the purpose of this study was to design a suitable model to analyze the industrial competitiveness of domestic autonomous operation technology industry, based on the Porter's diamond model. Based on a total of five evaluation factors and 13 detailed factors, the industrial competitiveness of the domestic autonomous operation technology industry was evaluated qualitatively and quantitatively. This industry, which is in the early stage of industrial development, was evaluated as 16.9 points relative to indexing industrial competitiveness. Currently, it is characterized by the simultaneous development of related regulations and core technologies, from the establishment of the scope of the industry. The industrial competitiveness evaluation considering these industrial characteristics is expected to serve as the basis for strategic support and new industrial policy, and impact a wide range of related industries such as shipping, logistics, ports, and shipbuilding and equipment industries.