• The Journal of the Korea Contents Association
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• v.21 no.3
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• pp.103-113
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• 2021

Rather than a directing method of existing animations, VR animation needs a different method of direction. Existing animations were displayed on a screen in movie theaters. But using an existing direction method for the 360° perspective in a VR animation makes it difficult for the user's gaze to move in a way the directors have intended. I analyzed 3 VR animations with a theoretical background of Rudolf Arnheim's visual perception theory and Bruce Block's visual factors that bring high attention. In the process of perception of space, focus on the gaze, movement of the gaze, the 'movement' factor was used most often to attract the gaze. An interactive VR animation attracts user's gaze by allowing users to participate in important points of the story. With an analysis of the animation, it proposed a gaze attraction through the movement of the character with an interaction directing method for reducing motion sickness. Also, it proposed intuitively attracting gaze movement by using GUI and attracting user's participation by using an interactive event with an interaction directing method of storytelling comprehension. With two types of directing proposal, we expect it to be utilized as a basic research method for attracting users to be immersed in storytelling while reducing cyber motion sickness, which is a problem in VR animation.

• Journal of the Korean Geotechnical Society
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• v.37 no.1
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• pp.29-41
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• 2021

Although underground works are essential to use underground spaces in urban areas efficiently, various damages caused by constructions have often occurred, making them major social problems. Since 2018, it is stipulated in the Special Act on Underground Safety Management that appropriate construction methods must be used in the design stage to prevent various damage cases. This Special Act includes establishing an area subject to underground safety impact assessment, analysis of ground and geological status, review of effects caused by changes in groundwater, review of ground safety, and establishment of measures to secure underground safety. This study area consists of various strata in order of landfill, sedimentary silt, sedimentary sand, sedimentary gravel, weathering zone, and foundation rock. Also, the slurry wall, a highly rigid underground continuous wall, was chosen as a construction method to consider high water table distribution and minimize the influence of the surroundings in this area. However, ground subsidence occurred on the road nearby in December 2019 due to the inflow of loosening soil to the construction area. Thus, several types of site investigations were conducted to suggest an appropriate analysis method and to find out loosed ground behavior and its area for the subsided site. As a result, new design soil properties were re-calculated, and the reinforcement measures were proposed through analytical verification.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.21 no.12
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• pp.87-96
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• 2020

To use a hydraulic structure effectively, the velocity of a river should be known in detail. In reality, velocity measurements are not conducted sufficiently because of their high cost. The formulae to yield the flux and velocity of the river are commonly called the Manning and Chezy formulae, which are empirical equations applied to uniform flow. This study is based on Chiu (1987)'s paper using entropy theory to solve the limits of the existing velocity formula and distribution and suggests the velocity and distance formula derived from information entropy. The data of a channel having records of a spot's velocity was used to verify the derived formula's utility and showed R2 values of distance and velocity of 0.9993 and 0.8051~0.9483, respectively. The travel distance and velocity of a moving spot following the streamflow were calculated using some flow information, which solves the difficulty in frequent flood measurements when it is needed. This can be used to make a longitudinal section of a river composed of a horizontal distance and elevation. Moreover, GIS makes it possible to obtain accurate information, such as the characteristics of a river. The connection with flow information and GIS model can be used as alarming and expecting flood systems.

• Applied Chemistry for Engineering
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• v.32 no.1
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• pp.35-41
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• 2021

VWTi, which is used as a commercial catalyst in NH3-SCR, exhibits excellent denitrification performance at 300 to 400 ℃, but there is a problem that efficiency decreases at low temperatures below 300 ℃. Research on catalysts containing promoter to increase low-temperature denitrification efficiency is steadily progressing. However, research on the cause of the improvement in low-temperature denitrification efficiency of the catalyst and the catalyst properties is insufficient. In this study, it was confirmed that by adding Sb to VWTi, denitrification performance was improved by more than 10% in NH3-SCR reaction below 300 ℃. At this time, the space velocity and the size of the catalyst particles were controlled to exclude the influence of external/internal diffusion. In addition, the catalytic properties according to the presence or absence of Sb were investigated by performing BET, TEM/EDS, O2-TPD, H2-TPR and DRIFTs analysis. It was judged that the addition of Sb increased the adsorbed oxygen species on the surface of the catalyst, thereby enhancing the redox properties of the catalyst at low temperature and exhibiting excellent denitrification performance.

• Journal of Life Science
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• v.31 no.6
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• pp.587-594
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• 2021

By 2050, 70% more food will be needed to fulfill the demands of a growing population. Among the solutions, cultured meat or clean meat is presented as a sustainable alternative for consumers. Scientists have begun to leverage knowledge and tools accumulated in the fields of stem cell and tissue engineering in efforts aimed at the development of cell-based meat. Cultured meat has to recreate the complex structure of livestock muscles with a few cells. Cells start to divide after they are cultured in a culture medium, which provides nutrients, hormones, and growth factors. An initial problem with this type of culture is the serum used, as in vitro meat aims to be slaughter free. Thus, it is contradictory to use a medium made from the blood of dead calves. The serum is expensive and affects to a large extent the production cost of the meat. A positive aspect related to the safety of cultured meat is that it is not produced from animals raised in confined spaces and slaughtered in inhumane conditions. Thus, the risk of an outbreak is eliminated, and there is no need for vaccinations and animal welfare issues. The production of cultured meat is presented as environmentally friendly, as it is supposed to produce less greenhouse gas, consume less water, and use less land in comparison to conventional meat production.

• The Journal of the Convergence on Culture Technology
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• v.8 no.2
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• pp.393-398
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• 2022

In order to experience and compete in car racing in reality, the barrier to entry is very high. It takes a lot of money and time to recruit or participate in a license, expensive vehicle, and stadium where the game can be played. Because of this problem, various equipment is used to create a feeling similar to real racing in their own space through sim racing equipment. Equipment similar to this reality is called sim racing equipment. The sim racing equipment can be divided into three categories. The first is a racing game device that can run virtual racing, the second is a steering wheel, seat, and cradle that are linked to the racing game device, and the third is a racing motion device that allows the body to experience the direction of movement in the racing game. In this thesis, the feeling of real car racing is based on game racing, and how similar reality to real racing is through the steering wheel and cradle equipment, which are equipment that can control game racing, and motion equipment that allows you to experience the direction of game racing. Let's check how the difference between real racing and data value changes through the G-Force direction and speed change values.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.50 no.6
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• pp.385-391
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• 2022

This paper presents to develop a path planning algorithm combining gradient descent-based path planning (GBPP) and particle swarm optimization (PSO) for considering prohibited flight areas, terrain information, and characteristics of fixed-wing unmmaned aerial vehicle (UAV) in 3D space. Path can be generated fast using GBPP, but it is often happened that an unsafe path can be generated by converging to a local minimum depending on the initial path. Bio-inspired swarm intelligence algorithms, such as Genetic algorithm (GA) and PSO, can avoid the local minima problem by sampling several paths. However, if the number of optimal variable increases due to an increase in the number of UAVs and waypoints, it requires heavy computation time and efforts due to increasing the number of particles accordingly. To solve the disadvantages of the two algorithms, hierarchical path planning algorithm associated with hierarchical particle swarm optimization (HPSO) is developed by defining the initial path, which is the input of GBPP, as two variables including particles variables. Feasibility of the proposed algorithm is verified by software-in-the-loop simulation (SILS) of flight control computer (FCC) for UAVs.

• Tunnel and Underground Space
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• v.32 no.2
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• pp.120-130
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• 2022

In this study, the applicability of the microseismic monitoring system based on the underground mine communication system has been verified by operation test in the domestic underground mine. The microseismic data consists of wavelet data and meta-data for mine safety management, and both data should be transferred, stored, analyzed and managed with proper method according to the purpose and size of each data. In order to select the optimal communication system for the microseismic monitoring system considering the underground environment as well as properties of data, various types of communication system have been tested and compared during operation test after installing the optical cable communication system, 2.4 GHz and 900 MHz wireless communication system through the underground mine tunnel and overground area of the test site. The integrated microseismic monitoring software, which was developed to secure the stability of data management and ease of use, has been updated according to findings from operation test. Through the operation test of the microseismic monitoring system including the communication system and the monitoring software, the technical basis was established corresponding to various requirements of the domestic mine for adoption of the microseismic monitoring system.

• Tunnel and Underground Space
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• v.31 no.6
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• pp.520-533
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• 2021

It is necessary to increase the blasting efficiency in order to minimize the economic loss caused when the excavation cross section is reduced due to the stability problem of underground mining development, and for this, a new blasting design is proposed. In this study, the blasting efficiency of the general design in the field, the suggestion designI, which added two columns to production blasting, and the suggestion design II, which added one column to create asymmetry, is compared. Advance rate and fragmentation were selected as the evaluation index of the blasting efficiency. In the case of advance rate, compared to the normal, the suggestionI improved by 6.07% and the suggestionII improved by 4.65%. In the case of fragmentation, based on P80, compared to the normal, the suggestionI reduced about 58% and the suggestionII was about 47%. Accoording to the evaluation index, the suggestion designI shows better blasting efficiency than the suggestion designII. But considering the additional work time and cost required for the suggestion designI due to the insignificant difference in the evaluation index results, the asymmetry V-cut, the suggestion designII, is judged to be a more suitable blasting design for the site.

• Tunnel and Underground Space
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• v.31 no.6
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• pp.623-646
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• 2021

As the demand for electric power increases with acceleration of electrification at home and abroad, the needs for coal-fired electrical power plant are accordingly increased. However, these coal-fired electrical power plants induce also many environmental problems such as increase of air pollutants, increase of possibility of land contamination by reclamation of coal ash, even though these power plants have a good economical efficiency. In case of a by-product of coal-fired electrical power plants, only 70% of them are recycled and the remaining 30% of by-product are fully buried in surrounding ground. Consequently, this study deals with coal ash backfilling mechanism in abandoned mine openings for the purposes of increasing the coal ash recycling rate as well as securing the mine area stability. In order to analyze the backfill and ground reinforcement by interaction between rock mass and backfills, the copying samples of discontinuous surface with different roughnesses were produced for bond strength tests and direct shear tests. And statistical analysis was also conducted to decide the characteristics of bond and shear behavior with joint roughness and their curing day. Numerical simulations were also analyzed for examining the effect of interface behavior on ground stability.