• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.30 no.1
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• pp.105-113
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• 2002

In this study, the steady state performance analysis program was developed for a turboprop engine, and its performance was analyzed at uninstalled and installed conditions. For the purpose of evaluation the developed program was compared with the performance data provided by the engine manufacturer and analysis results of GASTURB8.0 program. It was confirmed that the developed program was reliable because the results by the developed program were well agreed with those by GASTURB8.0 within %%. The linear and non-linear GPA(Gas Path Analysis) programs for performance diagnotics were developed, and selection of optimal measurement variables was studied. Furthermore, in order to investigate effects of the number and the kind of measurement variables, the linear and non-linear GPAs were analyzed with various measurement set. If the measurement parameters were properly selected, the reliable and economic faults detection might be possible even thought the small number of measuring parameters were used.

• The KIPS Transactions:PartC
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• v.18C no.3
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• pp.151-156
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• 2011

Google Android, which is one of the popular smart phone platforms, employs a security model based on application permissions. This model intends to reduce security threats by protecting inappropriate accesses to system resources from applications, but this model has a few problems. First, permission requested by an application cannot be granted selectively. Second, once the permission has been granted it is maintained until the application is uninstalled. Third, applications may acquire powerful permissions through user ID sharing without any notice to users. In order to overcome these limitations, we designed and implemented a flexible application permission management scheme. The goal of our scheme is to enhance security and user convenience while keeping compatibility to original platform. We also verified the operation of our scheme with real applications on Android emulator.

• Journal of Korean Society of Environmental Engineers
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• v.32 no.9
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• pp.862-869
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• 2010

Numerical analysis was done to evaluate the gas flow distribution in small scale SCR system which has $2.4{\times}2.4{\times}3.1\;m^3$ in volume and 25,300 Sm3/hr in flue gas flow capacity. Various types of baffles proposed for controlling the flow uniformity were evaluated by the CFD analysis to find the optimal geometry of the baffle in the SCR system. By installing baffles in the SCR system, the RMS (%) value was raised up to 6.2% compared with the baffle-uninstalled state. The effect of baffle thicknesses on the RMS (%) value was not shown within 0 and 8 mm in thickness, but the RMS (%) value was raised by 2.5% in 10 mm of baffles thickness, which causes the unstability in flow. By comparison between the shape of baffles, it is known that the lattice type baffle has better performance in controlling the flow uniformity than the circular truncated cone type baffle or mixer type baffle. RMS (%) values have more that 10% difference according to the shape of baffle type.

• Journal of the Korean GEO-environmental Society
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• v.17 no.1
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• pp.39-48
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• 2016

In this study, it can be shortened tunnel construction work period by introducing a single-shell tunnel does not placing the secondary concrete lining, a global research trend, reduction of the cost of the lining placement and number of benefits that can ensure the safety of long-term tunnel with a single shell it was to study the tunnel method. First, we analyze the design and construction practices relating to delete lining of the domestic design and construction practices and a comprehensive analysis of the stability study found a rock in good condition interval (1~3 grades), we propose that the lining uninstalled. In the case of domestic changes on the ground floor is very heavy underfoot conditions many so tunneling method by single shell as ground conditions are good and one preferred the water points that apply in less soil, the soil health and poor sections (4~5 grades) reflecting with respect to the concrete lining that is expected reasonable.

• Journal of the Society of Disaster Information
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• v.18 no.3
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• pp.566-573
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• 2022

Purpose: This study attempted to verify the effectiveness of the application of air sterilizers in elementary schools at risk of group infection among vulnerable groups in order to address fears of new infectious diseases that have increased since the outbreak of Middle East Respiratory Syndrome (MERS) and Coronavirus infection-19 (COVID-19). Method: One air sterilizer was installed in each classroom, cafeteria, and bathroom of an elementary school in Seoul, and surface and air samples were collected at a distance of 2m from the air sterilizer, and the bacterial reduction effect was analyzed compared to the uninstalled control group. Result: The sterilization effect on the surface was less than 2log CFU/cm² in both the control group and the test group, and the test group showed 54 to 87% less general bacterial colony formation than the control group. In addition, the sterilization effect in the air differed depending on the location of the air sterilizer, and the wall installation showed a reduction effect of up to 91% compared to the control group, and the central installation showed a reduction effect of up to 93%. Conclusion: As a result of the study, it is expected that the prevention of infectious diseases can be increased by maintaining the current quarantine program in elementary schools that conduct regular disinfection while applying air sterilizers. In addition, it is considered desirable to facilitate the inflow of air into the air sterilizer.

• Korea Science and Art Forum
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• v.24
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• pp.277-287
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• 2016

This study purpose is comparative analysis of environmental design checklist based on physical characteristics of the elders between Korea and Japan exhibition facilities. We were selected to represent the exhibition facilities in Korea and Japan and conducted field survey and understand the application status. The scope of the exhibition facilities space is entry, exhibition, public-service, educational activity and movement. And the elders physical characteristics are divided into 'sense(eye-sight, hearing, and feeling by touch)' / 'exercise (skeleton, movement, physical strength and muscular strength)'. Based on the checklist, we gave the score depending installation, part installation and uninstallation and then analyzed the average. The Results were as follows. First, Korea and Japan exhibition facilities are appear to similar and both above the average level. It is show that environment design reflects the physical characteristics of the elders. Second, exhibition space and educational activity space has lower score than other space, indicated most items are consist of the recommended. Most items appears as part of the preparation for this installed or uninstalled. Third, It showed that the installation is incomplete entries corresponding to the physical characteristics of the sensory area of the elderly (hearing). Therefore, there need to install additional information facilities such as voice, emergency call bell. Forth, the exhibition facilities appears differently depending on time of erecting and remodeling.