• Proceedings of the Korea Concrete Institute Conference
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• 2008.04a
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• pp.213-216
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• 2008

When using the light-weight form with polystyrene on slab, as a result of reducing the weight of slab, the span was increased or size of supporting member for slab was decreased. But capacity of punching shear resistance on the slab using the polystyrene form with plat plate system was deteriorated at critical section around the column. But standard for estimate of internal force did not exist, and established study was insufficient. This study performed the experiment on the punching shear for understanding punching shear force at the slab-column connection using the slab with polystyrene form. The principal variable was size of column, arrangement of polystyrene form and existence of shear reinforcement, and we planned four specimens. From the test, we analysed the crack, failure mode, road-displacement graph and punching shear strength, and capacity of punching shear resistance for slab using the polystyrene form was understood.

• Particle and aerosol research
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• v.10 no.1
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• pp.1-8
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• 2014

In this study, we have developed a real-time monitoring device for measuring $PM_{10/2.5/1}$ of ambient aerosol particles. The real-time PM (Particulate Matter) monitor was based on the light scattering method and had 16 channels in particle size. The laboratory and field tests were carried out to evaluate the performance of the PM monitor developed. Arizona Road Dust particles ranging from diameter of 0.1 to $20{\mu}m$ were generated as test particles in the laboratory test. The field test was carried out at the Seoul Meteorological Observatory. We can obtain the particle size and number concentration (particle size distribution) only from the real-time PM monitor developed. Therefore, the average density of aerosol particles was used to obtain the PM data from the particle size distribution. The $PM_{10/2.5/1}$ results of the PM monitor were compared with the data of the Grimm Dust Monitor (Model 1.108) and a beta ray gauge (Thermo Fisher Scientific). As a result, it was shown that the $PM_{10/2.5/1}$ results obtained by the real-time PM monitor agreed well with the data of the reference devices, and overall, the real-time PM monitor could be used as a PM monitoring device for real-time monitoring of the ambient particles.

• Journal of the Korean Institute of Rural Architecture
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• v.15 no.3
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• pp.17-24
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• 2013

This study examined and investigated architectural characteristics such as the use of buildings, the number of layers, and structure, and roof landscape characteristics such as roof types, materials, and color in rural villages which were located on the street on the assumption that the landscape of rural villages should be managed by considering visual aspects. The results were as follows. The commonest frequency was found in 'residence'(2/3) for the use of buildings and 'masonry structure'(2/3) for the structure. 'Wood structure' and 'light gauge steel structure(prefabricated structure)' were also commonly found. The results suggest that although many rural houses have partially improved by agricultural and fishery development projects and garden suburbs has been increased by city residents' desire for rural life, there have been still many old houses. Frequently used roof types were a gambrel roof and a hipped roof. Roof materials were mixed in several materials such as tiles, slate, panels, color steel plate, reinforced concrete, and asphalt shingles. Roof color was also mixed in several colors such as reddish N7 and N0.5 of Neutral color, 10R3/6 and 10R3/10 of R color, 7.5B4/10 and 7.5B7/8 of B color and 5G8/6 of G color. The result suggests that roof color impedes the landscape of rural villages on the street. Based on the results, some roofs of rural villages were improved by the support of the government or the local governments but there are still many old roofs. The mixture of improved roofs and old roofs mainly contributed to impeding the landscape of rural villages and it was probably caused by the lack of systematic landscape plans by individual improvement of buildings. Therefore, it is necessary to devise systematic landscape plans in consideration of local identity and neighboring environment. In particular, the guideline for roof color influencing a street landscape should be established.

• Journal of the Korean Institute of Rural Architecture
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• v.22 no.2
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• pp.1-8
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• 2020

This study is intended to derive the adaptive reuse techniques through the history and aspects of new construction, extension, repair, and other works, limited to the deep and narrow lots facing Seongan-gil and Nammun-gil in Nammun-ro 2 ga of Cheongju, the historic urban area. The results are as follows. 1) In the case of newly built reinforced concrete buildings, the central part of the top floor of the residence or all floors are opened to the open space(void) to facilitate lighting and ventilation. This is developed as a convection phenomenon due to the temperature difference from the slits between buildings, which affects the entire air flow of the block. 2) The buildings of extension and repair are composed of two-story masonry or steel frame, both the front store facing the road and the house on the back, but it looks like one because it is in contact with each other. If only a small gap between the front and rear buildings is restored to an external space or a space equipped with sun light, a small breath can be provided in lighting and ventilation. 3) The existing two-story wooden stores and houses have lost their external space due to repairs. With minimal intervention to restore the small courtyard, slits, and space under the eaves, it will not only improve lighting and ventilation, but also create a unique appearance as a segment of the elongated store.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.23 no.5
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• pp.456-464
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• 2014

Commercial vehicle drivers typically feel more fatigued compared to general-public drivers. because they spend longer periods of time driving and experience more rough road conditions. This study showed that the application of a magnet, a linear spring, and a seat suspension with nonlinear characteristics was the optimal design to increase comfort while driving. The resonant frequency for the optimal design suspension was 2.8 Hz, and the stiffness was analyzed through displacement-load experiments. Vibration transmissibility was analyzed by suspension stiffness and the existing dynamic compression. The magnetic spring type was at 0.875. As a result, the X-type magnetic spring performed better than the existing spring at 0.729.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.8 no.5
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• pp.26-37
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• 2009

This paper suggests a sensor's placement method for detecting the dilemma zone problem when real-time driver's safety service is provided at signalized intersections by multiple pointed traffic sensors using USN environments. For detecting the dangerous situations from vehicles accelerating through yellow intervals, red-light running and stopping abruptly like as dilemma zone problem, VISSIM(microscopic, behavior-based multi-purpose traffic simulation program) is used to perform a real-time multiple detection situation by changing the input data like as various inflow-volume, design speed change, driver perception and response time. As a result, the optimal interval of traffic sensors is 20~27m, and the initialized sensor location from stop-line is different according to road design speed. Moreover, the pattern of detection about dilemma zone is also different according to inflow-volumes. This paper shows that the method is useful to evaluate the sensor's placement problem based on micro-simulation and the results can be used as the basic research for USN services.

• Journal of the Korean association of regional geographers
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• v.20 no.3
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• pp.300-314
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• 2014

The study is to systematically review "DaedongYeojiJeondo", the mid-sized wood block map of Chosun to shed light on the cartographic characteristics not discovered by previous studies. First it was discovered that Kim Jung-ho is the developer of the map as the distance information from Seoul to towns is identical with the information on "Daedong Jiji" the manuscript map drawn by Kim Jung-ho himself (assumed to live from 1804~1866) that is still remaining unfinished. Second, the information Kim Jung-ho wanted to specify most precisely and specifically was distance from Seoul to towns and for this purpose he invented unique symbols for towns in tiny size on the map. Third, in selecting information to mark on the map including road network, street information, mountain routes and streams and location of islands, "DaedongYeojiJeondo" is not just a simple smaller copy of "DaedongYeojido" but an independent creative work as it is much different in many aspects of quality. Forth, but still "DaedongYeojiJeondo" and "DaedongYeojido" have something in common in the fact both of them tried to mark land and mountain routes and streams most precisely and specifically.

• Journal of the Korean institute of surface engineering
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• v.41 no.3
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• pp.121-128
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• 2008

High strength 7xxx aluminum alloys have been applied to automotive bump back beam of the some limited model for light weight vehicle. The aluminum bump back beam is manufactured through extrusion, bending and welding. The residual stress given on these processes combines with the corrosive atmosphere on the road spreaded with corrosive chemicals to melt snow to occur the stress corrosion cracking. The composition of commercial 7xxx aluminum has Zn/Mg ratio about 3 and Cu over 2 wt% for better strength and stress corrosion cracking resistivity. But this composition isn't adequate for appling to the automotive bump back beam with high resistance to extrusion and bad weldability. In this study the composition of 7xxx aluminum alloy was modified to high Zn/Mg ratio and low Cu content for better extrusion and weldability. To estimate the resistivity against stress corrosion cracking of this aluminum alloy by slow strain rate test, the corrosion atmosphere and strain rate separate the stress corrosion cracking from conventional corrosion must be investigated. Using 0.6 Mol NaCl solution on slow strain rate test the stress corrosion cracking induced fracture was not observed. By adding 0.3% $H_2O_2$ and 0.6M $Na_2SO_4$ to 1M NaCl solution, the corrosion potential and current density of polarization curve moved to active potential and larger current density, and on the slow strain rate test the fracture energy in solution was lower than that in pre-exposure. These mean the stress corrosion cracking induced fracture can be estimated in this 1M NaCl + 0.3% $H_2O_2$ + 0.6M $Na_2SO_4$ solution. When the strain rate was below $2{\times}10^{-6}$, the stress corrosion cracking induced fracture start to be observed.

• Journal of the Korea Society of Computer and Information
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• v.25 no.12
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• pp.299-303
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• 2020

Currently, electric furnace oxide slag is mostly used for soil or road use due to its nature. Although electric furnace oxidation slag is an industrial byproduct, not a circulating aggregate, the shortcomings of electric furnace oxidation slag are gradually being resolved due to the development of technology, and it is said that electric furnace oxidation slag is enough to be used as aggregates in light of research and technology conditions outside of Korea. However, there are difficulties in expanding construction and application, given that the current standard for electric furnace oxid slag only defines recycling purposes and does not have specific regulations. Therefore, institutional supplementation is needed to utilize oxidation slag as electricity. In this study, the laws and system related to oxidation slag by electricity are reviewed, laws related to recycled aggregate are examined, and measures for improvement are proposed.

• Journal of the Korean Society of Marine Environment & Safety
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• v.28 no.7
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• pp.1129-1139
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• 2022

Collision accidents happen frequently. The majority of ships involved in collisions in the coastal areas of Korea are middle and small size ships. The proportion of collision accidents is only 9% of all types of marine accidents; however, the number of casualties resulting from collisions is 34.4% of all human life damages. Generally, as reported by the people involved in these collisions, the navigation lights of the opponent ships were poor and invisible when the accident happened even though the weather and visibility were good. Furthermore, there are many insistences for poor navigation light conditions of the opponent ship in the bay or harbor. Therefore, it is necessary to analyze the present conditions and safety of navigation lights. Therefore, in this study, we examined the rules and books of navigation lights and compared it to that of other transportation systems, such as aircraft, trains, and road vehicles. Furthermore, we analyzed the current marine traf ic circumstances and ship collision accidents that happened in the past 5 years. Additionally, a questionnaire was prepared to gather the opinion of ship experts and secure the objectivity for improvement methods of navigation lights. Finally, methods to improve the navigation lights on ships were devised.