• Journal of the Korean housing association
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• v.15 no.3
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• pp.53-62
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• 2004

Recently the landscape of housing has been emphasized. This trend seems to reflect the negative aspects of housing landscape in urban area. Throughout the analysis on the various visual density index, the following findings were obtained; 1) Elevation blockage ratio(EBR) was permitted differently according to the types of housing blocks, and the preference of block layout was different to the location of site. 2) EBR regulation level was acceptable. But 40m level of general area should be stepped up to the 35m level. 3) The correlation between the floor area ratio(FAR) and the EBR was not high. Therefore it is reasonable to regulate the EBR to the location. 4) Elevation coverage ratio(ECR) was highly correlated with the FAR. It means that FAR can substitute for the ECR, and ECR should be regulated to the level of FAR.

• Journal of the Korea Safety Management & Science
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• v.22 no.2
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• pp.39-46
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• 2020

This paper recognizes the risk of ignition of air fryer (machine that can cook fried dishes with hot air without oil) that is far exceeding the sales rate of microwave ovens, which is necessary to modern household kitchen, and identifies fire risk through the operation principle of the process of heat transfer, and the main structure of the machine. The fire test that we conducted is to observe the risk of ignition of the machine due to the damage to the safety system and the possibility of igniting oil paper along with food, to experiment with the possibility of ignition due to blockage of the exhaust due to obstacles, and accumulation of oil stains on the hot wire, and to present the method of fire control and devise countermeasures.

• Journal of the Korean Institute of Rural Architecture
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• v.19 no.4
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• pp.77-85
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• 2017

In order to preserve beautiful coastal areas landscapes of Jeju Island's the landscape resource, Jeju Special Self-Governing Province is dedicated to protecting the landscape through legal regulations and deliberations. However, the Coastal Landscape of Jeju Island was continuously damaged by due to increased tourist and high development pressure. Based on buildings along the Coastal Road in Aeowal of Jeju Island, this study focused on Management Status of Coastal Areas Landscapes through the Analysis of Building Landscape Elements. As a result, 1) It was effective to limit the use and scale of buildings through legal regulations such as Use zoning. 2) The result of analysis on the physical landscape elements of buildings showed some of the them have the damage values despite passing the review of Architecture Committee. Therefore Landscape Policies required institutional maintenance. 3) As physical landscape Elements of buildings is a minimum quantitation criterion of not less than 1.5 for D/H, or less than a factor of $27^{\circ}$ for angle of elevation and not less than 7.8m for elevation blockage ratio was presented as a criterion for preventing damage to the minimum Coastal Landscape.

• Proceedings of the Korea Society for Energy Engineering kosee Conference
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• 1999.05a
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• pp.151-157
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• 1999

In this study, tile characteristics of three dimensional flow fields in centrifugal flump impeller are investigated by numerically. Detailed analysis and understanding of flow field in centrifugal pump are very important to predict performance of components. The three dimensional viscous fluid flow in centrifugal pump is distingushed isentropic process region from irreversible process region by wall shear effect, secondary flow, centrifugal and Coriolis forces, variation of boudary layers. Development of low momentum region by viscous fluid flow in the centrifugal impeller causes stall and blockage which is irreversible process region, and resulting in decrease of the performance and efficiency of centrifugal pump. Especially, the result is that Coriolis and centrifugal forces are most powerful factors which are increasing the irreversible region.

• Journal of the Regional Association of Architectural Institute of Korea
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• v.20 no.6
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• pp.33-40
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• 2018

The coastal village in Woljeong-ri, Jeju is highly preferred by tourists because of its unique natural landscape different from inland areas. Especially, the number of buildings in the coastal area of the village is increasing due to escalating commercial value. Buildings are densely developed, along the seaside, resulting in privatization of coastal landscape. This results in blocking of landscape and psychological exchanges between the coastal village and coast. This study analyzed the actual conditions of coastal landscape before and after 2010, when the number of tourists and demand for development were increased in the coastal area of the coastal village in Woljeong-ri, Jeju. In this study, open index, visible horizontal index, elevation angle, elevation blockage and visible facade index were used to compute objective indicators of coastal landscape status. The analysis reveals visible facade index, a complex landscape assessment indicator, was increased by 7 times after 2010 as compared with before 2010. As such, there are many coastal villages in Jeju similar to Woljeong-ri that have a high landscape value and are in need of management. A comprehensive measure including a system for management of coastal landscape is urgently required to create narrative landscape in Jeju.

• Journal of Satellite, Information and Communications
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• v.10 no.4
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• pp.39-45
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• 2015

Satellite communication is high-speed large-capacity transmission in such a manner as to communicate with satellites in the chamber, and there is a wide area communication, but is not the security of the information. To compensate for this, AES encryption was applied to the CTR and CBC mode. Also, Blockage channel using a Markov chain to determine the impact caused by obstacles such as trees or buildings between the transmitter and the receiver was composed of Urban and Open Environment. The results of analyzing the performance of satellite communications over a high-speed link-based simulation, If applying encryption, performance of security is complementary but performance of the BER was aggravated and In the Open Environment fewer obstacles confirmed the BER performance is improved than the Urban Environment many obstacles.

• Journal of Navigation and Port Research
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• v.36 no.6
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• pp.429-435
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• 2012

Although GNSS hardware and software technologies have been steadily advanced, it is still difficult to obtain reliable positioning results in the area with lots of signal blockage. In this study, algorithms for integrated GPS and GLONASS double difference relative positioning were developed and its performance was validated via simulations of signal blockages. We assumed that signal blockages are caused by high-rise buildings to the east, west, and south directions. And then, GPS-only and integrated GPS/GLONASS positioning accuracy was analysed in terms of 2-dimensional positioning accuracies. Compared with GPS-only positioning, the positioning accuracy of integrated GPS/GLONASS improved by 0.3-13.5 meters.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.34 no.4
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• pp.11-16
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• 2006

Effects of an orifice on suppression of pressure oscillation in a fluid feeding line are investigated numerically through the installation of an orifice inside the feeding line. Based on linear acoustic theory, acoustic-damping effect of an orifice is emphasized in this study. When an orifice is installed at the node of pressure oscillation corresponding to the anti-node of velocity oscillation, damping capacity is maximized. On the other hand, the orifice installed at the anti-node of pressure oscillation has little damping capacity. As the blockage ratio and thickness of an orifice increase in the feeding line, damping factor increases. The feeding line with smaller diameter has more damping capacity, but damping factor increases more appreciably with blockage ratio in the feeding line with larger diameter.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.21 no.1
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• pp.89-98
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• 1997

Compression waves propagating in a high speed railway tunnel impose large pressure fluctuations on the train body or tunnel structures. The pressure fluctuations can cause ear discomfort for the passengers and increase the aerodynamic resistance of trains. As a fundamental research to resolve the pressure wave phenomenon in the tunnel, a steady theory of Chester-Chisnell- Whitham was applied to a simple shock tube with a sudden cross-sectional area reduction to model trains inside the tunnel. The results of the present theoretical analysis were compared with the experiments of the shock tube. The results show that the reflected compression wave from the model becomes stronger as the strength of incident compression wave and the blockage ratio increase. However, the compression wave passing through the model is not strongly dependent on the blockage ratio. The theoretical results are in good agreement with the experiments.

• Environmental Engineering Research
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• v.22 no.1
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• pp.95-107
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• 2017

Adsorption equilibrium and kinetic behavior of two toxic heavy metals hexavalent chromium [Cr(VI)] and mercury [Hg(II)] on mustard oil cake (MOC) was studied. Isotherm of total chromium was of concave type (S1 type) suggesting cooperative adsorption. Total chromium adsorption followed BET isotherm model. Isotherm of Hg(II) was of L3 type with monolayer followed by multilayer formation due to blockage of pores of MOC at lower concentration of Hg(II). Combined BET-Langmuir and BET-Freundlich models were appropriate to predict Hg(II) adsorption data on MOC. Boyd's model confirmed that external mass transfer was rate limiting step for both total chromium and Hg(II) adsorptions with average diffusivity of $1.09{\times}10^{-16}$ and $0.97m^2/sec$, respectively. Desorption was more than 60% with Hg(II), but poor with chromium. The optimum pH for adsorptions of total chromium and Hg(II) were 2-3 and 5, respectively. At strong acidic pH, Cr(VI) was adsorbed by ion exchange mechanism and after adsorption reduced to Cr(III) and remained on MOC surface. Hg(II) removal was achieved by complexation of $HgCl_2$ with deprotonated amine ($-NH_2$) and carboxyl (COO-) groups of MOC.