• Journal of the Korea institute for structural maintenance and inspection
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• v.25 no.5
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• pp.135-140
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• 2021

In this study, the concrete aggregate shape features were extracted from the cross-section of a normal concrete strength cylinder, and the compressive strength of the cylinder was predicted using artificial neural networks and image processing technology. The distance-angle features of aggregates, along with general aggregate shape features such as area, perimeter, major/minor axis lengths, etc., were numerically expressed and utilized for the compressive strength prediction. The results showed that compressive strength can be predicted using only the aggregate shape features of the cross-section without using major variables. The artificial neural network algorithm was able to predict concrete compressive strength within a range of 4.43% relative error between the predicted strength and test results. This experimental study indicates that various material properties such as rheology, and tensile strength of concrete can be predicted by utilizing aggregate shape features.

• Journal of the Korea institute for structural maintenance and inspection
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• v.26 no.6
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• pp.193-203
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• 2022

In this study, in order to compare the seismic performance of steel structure beam-column connection details and non-scallop connection details mainly used in Korea, a full-scale static cyclic loading test and FEM analysis were conducted through the same modeling as the experiment. For quantitative numerical comparison, the strain concentration ratio and moment transfer efficiency used in previous studies were cited. As the welding area of the beam web decreased, the deformation rate of the beam flange increased, and the plastic deformation capacity according to the rotation angle decreased or brittle fracture occurred. Comparing the analysis results with the experimental results, the possibility of brittle fracture tended to increase when the web welding ratio for the total cross-sectional area of H-shaped fell below 60%.

• Proceedings of the Korea Water Resources Association Conference
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• 2023.05a
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• pp.302-302
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• 2023

최근 도시의 왜곡된 물순환 문제를 해결하기 위해서 저영향개발(Low Impact Development, LID) 기법을 적극적으로 도입하고 있다. 저영향개발은 자연의 침투, 증발산, 여과 등의 자연기작을 모방하여 강우유출수를 침투 및 저류시키는 기법으로 물순환 체계를 회복시킬 수 있다. 저영향개발 기법의 하나인 벽면녹화는 건축물이나 기반 시설물의 벽면과 같은 인공지반에 기반을 조성하고 식물을 식재하는 시설로 짧은 시간에 녹지 면적을 만들 수 있다. 또한, 건축물로 인해 생겨난 수직적인 면을 녹지로 활용할 수 있어 도시에 매우 특화된 시설이다. 본 연구는 벽면녹화의 저영향개발 시설로서의 성능을 확인하기 위해 실내 실험을 진행하여 강우유출수 저감효과 및 지체시간 지연효과를 확인하였다. 강우유출수 저감효과는 유입량 대비 저류량을 기준으로 유출저감률을 산정하여 분석하였으며, 총 유출시간을 측정하여 지연효과를 판단하였다. 벽면녹화 현장실험 대상지는 경상남도 양산시 물금읍 부산대학교 양산캠퍼스에 위치한 한국 녹색인프라저영향개발센터이며, 실내에 플랜터형 벽면녹화 시스템을 적용하였다. 부산시 금정구 2012년~2021년의 강수량을 사용해 백분위수 강우사상을 기준으로 30, 50, 70mm/hr의 강우 시나리오를 선정하였다. 물순환 효과를 판단하기 위해 불투수면을 대조군으로 설정하여 불투수면의 유출이 종료되는 시점까지 지표면 유출을 모니터링 하였다. 그 결과, 30, 50, 70mm/hr 시나리오별 유출률은 91.76%, 92.18%, 94.54%로 불투수면과 대비하여 유출이 적게 발생하였으며 총 유출시간은 불투수면대비 47분, 88분, 58분 증가하여 지연효과가 있음을 확인하였다. 본 연구는 실험을 통해 벽면녹화의 수문학적 성능을 분석하고자 유출량 저감효과와 지연효과를 확인하였다. 추후 다양한 강우 시나리오와 제원에 따라 실험이 수행된다면 더 정확히 벽면녹화의 물순환 효과를 확인할 수 있을 것이다.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.28 no.5A
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• pp.719-727
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• 2008

The tensile and bond performance of GFRP rebar are different from those of conventional steel reinforcement. It requires some studies on concrete members reinforced with GFRP reinforcing bars to apply it to concrete structures. GFRP has some advantages such as high specific strength, low weight, non-corrosive nature, and disadvantage of larger deflection due to the lower modulus of elasticity than that of steel. Bridge deck is a preferred structure to apply FRP rebars due to the increase of flexural capacity by arching action. This paper focuses on the behavior of concrete bridge deck reinforced with newly developed GFRP rebars. A total of three real size bridge deck specimens were made and tested. Main variables are the type of reinforcing bar and reinforcement ratio. Static test was performed with the load of DB-24 level until failure. Test results were compared and analyzed with ultimate load, deflection behavior, crack pattern and width.

• Journal of the Korean Society of Radiology
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• v.11 no.5
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• pp.297-302
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• 2017

Recently, building materials and air purification filters with eco-friendly charcoal are actively studying to reduce the concentration of radon gas in indoor air. In this study, radon reduction performance was assessed by designing and producing new panel-type activated carbon filter that can be handled more efficiently than conventional charcoal filters, which can reduce radon gas. For the fabrication of our panel-type activated carbon filter, first the pressed molding product after mixing activated carbon powder and polyurethane. Then, through diamond cutting, the activated carbon filter of 2 mm, 4 mm and 6 mm thickness were fabricated. To investigate the physical characteristics of the fabricated activated carbon filter, a surface area and flexural strength measurement was performed. In addition, to evaluate the reduction performance of radon gas in indoor, the radon concentration of before and after the filter passes from a constant amount of air flow using three acrylic chambers was measured, respectively. As a result, the surface area of the fabricated activated carbon was approximately $1,008m^2/g$ showing similar value to conventional products. Also, the flexural load was found to have three times higher value than the gypsum board with 435 N. Finally, the radon reduction efficiency from indoor gas improved as the thickness of the activated carbon increases, resulting in an excellent radon removal rate of more than 90 % in the 6 mm thick filter. From the experimental results, the panel-type activated carbon is considered to be available as an eco-friendly building material to reduce radon gas in an enclosed indoor environment.

• Journal of Korean Society of Archives and Records Management
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• v.2 no.1
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• pp.41-66
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• 2002

This paper examines urgent issues of establishing the presidential library in relation to the current standing of the Government Archives and Records Service. As government records have been tremendously accumulated every year, the Government Archives and Records Service will be full within three years, which indicates that the constructing of new storage repositories is an emergent issue. In addition, presidential records are one of the most significant and influential public properties for preserving historical value and interpretation at the national level. Some serious concerns relating to the presidential library are raised for consideration. First of all, it is compulsory to preserve presidential records and to construct the presidential library. Second, the presidential library performs a variety of functions including the acquisition, preservation, access, reference, research, education, and display of presidential records as well as exhibits of public activities and administration personally and in public during the president' regime. A new presidential library should function as both of a depository and museum of presidential records through systematic arrangement and display. Thus a new repository of the Government Archives and Records Service should be co-constructed with the presidential library within the same boundary. Third, a newly constructed presidential library should be at least double- or triple- sized more than estimated in order to contain all related holdings. Fourth, to take custody of public records across the legislature, judiciary and administration, the Government Archives and Records Service should be directed by an official at the level of vice-minister and upgraded to an independent office such as "National Archives and Records Administration." Fifth, the presidential library's location and surrounding environments should be selected with careful planning.

• Archives of design research
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• v.20 no.3 s.71
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• pp.191-202
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• 2007

In these days, open signboard system is controlled by administrative policy and law, but there is no consideration for different types of building. As such, this study aims to propose planning criteria for streetside commercial buildings, such as elevation and mass design of buildings, layout of signboard attached to the building elevation with consideration for streetscape. In mass planning for streetside commercial buildings, the building type with front open space keeps lower open signboard density than the building type directly leading to the street. It is desirable that open signboard of lower floor part is attached by a horizontal type, open signboard of low medium floor part by a projected vertical type, open signboard of high medium floor part and roof part with a minumum attachment of open signboard. As for elevation planning relative to open signboard, it is desirable that an irregular wall type is more useful than a regular wall type to control open signboard. And in all cases, horizontal element facade has a handicap to control the quantity of signboard. If the building has a corner, the piloti should be used in the corner of lower story for smooth circulation of pedestrians and emphasizing the transparency of elevation. Specially, in the case of a round corner, the corner should be emphasized by the composition of high transparent mass.

• Journal of Animal Environmental Science
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• v.14 no.3
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• pp.167-174
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• 2008

This survey was conducted to investigate housing types of Korean native cattle and beef cattle farms in Korea. The farm sized over 50 heads of cattle, 7,433 farms were surveyed. Regarding housing types for Korean native cattle and beef cattle, litter barn, freestall, mooring+litter ground and others accounted for 87.1, 9.8, 3.0, and 2.9 %, respectively. Most of Korean native cattle and beef cattle farms (94.7%) used litter floor rather than scraper. As for roof types, slate, panel, iron plate, galvanized plate, colored iron plate and sunlight represented 32.2, 13.7, 12.2, 10.2, 9.7, and 8.9 %, respectively. Open side wall type and winch curtain were 55.6, and 47.6 %, respectively. Bigger farms seemed to used more winch curtain than open style. Utilization period of automatic feeder, waterer, electric facility, and cooling facility was 6.7, 8.0, 8.5, and 6.0 years, respectively.

• Journal of Animal Environmental Science
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• v.15 no.3
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• pp.251-262
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• 2009

In this research dairy cattle barn facilities what are 4,198 houses hold over 50 heads were surveyed by scale and province. Full-time farms hold over 50 heads breed total 344,514 heads. Each of Farms holds 50 to 99 heads were 79.8 percent and breed average 82.1 heads. Dairy cattle barns were constructed september 1995 averagely. Each of barns have $1,740.0\;m^2$ scale. The construction type of dairy cattle barn was almost litter barn type 84.0%, freestyle type 5.1%, mooring+litter ground type 17.3% and other types 4.4%. The litter barn type was popular in small farms. But in large farms, freestyle type was popular than small farms. The construction type of dairy cattle barn was almost litter barn type 84.0%, freestyle type 5.1%, moohng+ltter ground type 17.3% and other types 4.4%. Type of dairy cattle robotic milking system was pipeline 41.5%, herringbone 22.8% and tandem 35.8%. The pipeline type was popular in small farms which have 50~99 heads. But in large farms which have over 200 heads, tandem type was popular than small farms. Proportion of floor type of dairy cattle barn was almost litter type 94.9%. Scraper type was popular in large farms than in small farms. Proportion of roof type of dairy cattle barn was slate 32.5%, vinyl 16.3%, sunlight 11.1%, panel 10.9, zinc plate 8.8 and steel plate 8.3%. Roof type was lots of slate type before 1995. But vinyl type is increasing after 1995. Proportion of wall type of dairy cattle barn was almost open type 83.3% and winch-curtain 26.8%. Utilization period of dairy cattle barn was 9.2 years about milker, 7.9 years about automatic feeder, 9.2 years about waterer and 10.4 years about electric facilities. In this results, there were lots of improvements about automatic feeder.

• Korean Journal of Soil Science and Fertilizer
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• v.45 no.4
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• pp.475-483
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• 2012

Recently, agricultural lands decrease sharply, which was caused by urbanization, land consolidation, road construction, and innovation city construction, etc. In particular, Goyang, Chenan and Wonju city were had severe land use change. Therefore, we analyzed changes of land use, soil properties, and soil information in order to provide the basic soil information and soil management practice in these cities. The results are summarized as follows. The area of crop cultivated land in Korea (2011) was reduced to 17.3ha compared to ones from the previous year (2009). The paddy field decreased by 24.2 ha but, upland field increased by 7.0 ha. The reasons for the reduction of the paddy field were converting paddy field to upland (20.7 ha) > public facilities (3.2) ${\geq}$ building (3.2) > idle land (1.3) > and others (0.9). Other reasons for reduction in the upland field were switching upland to paddy field, (20.7 ha) > land developed (4.5) > and restoration (0.3) respectively. The main reason of converting paddy field to upland was changing from rice to more profitable upland or greenhouse crops. The cropland area (paddy fields, upland, orchard) of Goyang, Cheonan, and Wonju city were reduced to 1,466 ha, 9,708 ha and 6,980 ha respectively. The ratio of cropland area in each city was reduced by 45~25% dramatically compared to upland soil survey project in Korea (1995~1999). These data were compared with MiFAFF statistics data to use for land use cover map of Ministry of environment. But they were differences significantly. Therefore, intensive investigation should be advised throughout the utilization plan. The paddy fields located in small valley in Wonju city were changed into upland or orchard. The drainage classes of soil have been deteriorated because the flows of water were intercepted by road construction and other disturbance to water flows. In particular, paddy fields have been changed to not only upland, orchard, greenhouse cultivation but also to fallow and soil dressing on paddy in Wonju city. The soil suitability classes of paddy field in Wonju innovation city were the 3rd grade for 70.8% of the area and the 4th grade for 29.2%. The soil suitability classes of upland was the 4th grade for 88.7% of the area. Fortunately, good soil suitability classes were not belong to innovation city in Wonju. So, the good farm land should be conserved and revise the related law.