• Proceedings of the Korea Concrete Institute Conference
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• 2008.04a
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• pp.673-676
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• 2008

Recent trends show an increased usage of 'colored concrete', a inorganic pigmented concrete mix, especially in small to large scale buildings. However, due to lack of regulations, current usage of colored concrete indicates a lack of consideration for safety factors and aesthetic aspects. Sometimes color pigmentation used in paints are inappropriately used in concrete, and in many cases the addition of coloring material is done without proper research into how structural characteristics of resulting concrete may have been affected. To resolve these issues, some construction sites apply ASTM or ACI regulations. However, such regulations incorporate elements that cannot be applied in Korea, which makes their domestic application impractical. In this paper, the primary aim is to determine to what extent the basic material characteristics of concrete is affected by the variety and quantity of different color pigments, and in so doing establish a foundation for future reference in case of construction projects involving the use of colored concrete.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.65 no.4
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• pp.555-560
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• 2016

Recently, many countries have placed great attention on energy security and climate changes. Governments are promoting the construction of renewable energy projects with regulatory support in Korea. Despite an increasing penetration of renewable resources, however, the photovoltaic and wind power are underutilized due to the endemic problems such as difficulties of output control and intermittent output. The Energy Storage System (ESS) is proposed as a good solution for solving the problems and has been studied in both the private business and the government. However, because of inefficient aspects, the research has been carried out for improving high costs and a small capacity. In addition, the ESS is currently installed for using only one purpose which is frequency regulation or transmission congestion relief such that has an economic limitation. Therefore, methods which are becoming economically justifiable to increase the penetration of the ESS is required. Thus, this paper presents in terms of operation efficiency to improve economic feasibility of the ESS currently used. mainly, there are two aspects for the operation efficiency. Firstly, it is intended to improve the utilization rate through a process that can utilize the ESS for various purposes. It is necessary to be able to use for other purposes by classifying and clustering for increasing the efficiency of availability. The clustering method is proposed to conduct the grouping the ESS. Especially, it is proposed to utilize ESS for frequency regulation service which is the one of ancillary services in the power system. Through case studies, it is confirmed to secure the necessary resources by clustering small size ESS.

• Journal of the Korean Institute of Landscape Architecture
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• v.35 no.6
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• pp.48-63
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• 2008

This research is to apply suitable natural ecosystem evaluation criteria in order to develop the ecosystem conservation, restoration and ways to build substitute habitats as a compensation plan for damaged soundly natural ecosystems in small-scale projects such as resource recovery facility, filtration, etc. The environmental ecology evaluation i.e. generally based on their actual vegetation, community structure, wildlife, water system survey were measured the primary plans for reflecting unique natural environment level of site. As a result, it is necessary to conserve the land in fallow type of wetland, good conservative condition of deciduous forest, wetlanded watercourse for amphibia and reptiles crossing. However, the plan of filtration plant was destroyed wetland(sound ecosystem), natural forest, asian toad spawning area. According to the result of it schemed to build alternative wetland and spawning area, plan to healthy ecosystem and surface soil transplantation as compensation plan. The alternative wetland and spawning area are not only created a various water levels like depth of water is $0{\sim}30cm,\;30{\sim}60cm$, more than 1.5m but also it leads to asian toad spawning and wildlife inhabitant. Moreover, the ecosystem and surface soil transplantation be applied to use the Quercus acutissima forest resources(114 upper trees, 71 canopy trees, 401 shrubs) and surface soil$(5,072m^3)$ in ecology creation sets.

• Journal of the Korean Institute of Rural Architecture
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• v.17 no.3
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• pp.11-18
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• 2015

This study is aimed to clarify the transitional characteristics of old roads and alleys lasting more than 100 years(1915-2015) in traditional urban area(Seongan-dong) of cheongju, historic inland and castle city of Korea. Cheongju castle had been completely destroyed In 1915, and urban structures been also altered last 100 years from 2015 now. Periodically, after destruction of castle, existing roads were extended and transformed to straight line for connecting with around. Expanding urban area to all directions of castle boundary in 1930-40s, town planning were created. These projects were completed in 1960-70s, the street network was built as they are. Since the 1980s, changes had been occurred in the details such as an extension of the unexecuted roads, the opening of fire lane in a block, and etc. In change and construction of roads, urban district plan in 1939 and reorganization since 1967 were planned and established with the type, location, and width of the large, medium and small roads based on data before destruction of castle. Except the width of 25m Sajikro(large3-1) and Sangdangro(large3-8,9,10), the width of 15m Namsaro(medium2-1) and Namjuro (medium2-4) as an extension of the roads, the other roads were small roads equivalent to the existing roads, and so remain intact figure of streetscape. As such, roads of east-west and north-south cross type, roads showing the outline of Cheongju castle fortress, and alleys outside the south gate are sustained in Seongan-dong of cheongju as historic urban area, and also present roads are delicately executed to the existing urban fabric.

• Journal of Korean Society on Water Environment
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• v.22 no.3
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• pp.475-481
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• 2006

The major problem in closing water like lakes and ponds in Korea is that because they are exposed to surrounding, so easily polluted. The pollution in closing water can be caused by not only artificial factor like sewage but also natural factor like elution from sediment. For insurance of safe and satisfied water source, lots of studies and projects are now going on. In this study, we examined the behavior and effect of microbubble ($3{\sim}10{\mu}m$) produced by device called O.S.D (Oxygen Solubillization Device) in small size pond. The value of oxygen transfer coefficient ($K_La$) was 0.68/min independently of air flow rate, 6.5 times higher than commercial aeration stone and the variation of nitrogen concentration was $0.008NO_3/O_2$, DO concentration was potentially saturated for 24 hr. From the results of pilot plant, SOD of experiment (O.S.D) and control were $12.18gO_2{\cdot}m^{-2}{\cdot}d^{-1}$ and $47.95gO_2{\cdot}m^{-2}{\cdot}d^{-1}$ respectively. In conclusion, because O.S.D has extraordinary physico-chemical characteristics, it can contribute to improvement of both the waterbody and the sediment environment.

• Korean Journal of Construction Engineering and Management
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• v.17 no.5
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• pp.97-107
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• 2016

CM services have been focused on the advancement of the CM industry and expansion to overseas market based on CM capabilities. However, there has been lack of quantitative and comprehensive research to investigate current CM trends and prospects for improving competitiveness. In this sense, the purpose of this study is to statistically analyze total of 3,453 CM service contracts over the past 18 years (between 1997 and 2014) in term of market type, contract size, owner's type, commodity type. Finding of this research reveal that 1) compared to 2005, CM market size in 2015 increased as much as 2.5 times, and that 2) domestic CM projects count for 87.5%, architectural project 88.4%, less than 1 billion won small contracts 75%, respectively. Also, recently as CM company are developing capability and competitiveness, 1) overseas CM market share has grown up to 20% among total CM contract amount, and 2) CM contracts by private owners has increased 3 times demanding the total management services based on high technical capability. Additionally, the result of this paper supports the growth path model proposed by Jung et al. (2014), where a path from Domestic Public (DP3) and Domestic Private (DC2) CM projects towards the expansion to International Private (IC5) contracts was quantitatively analyzed. Implications for other practical issues are also briefly discussed.

• Journal of the Korean Institute of Landscape Architecture
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• v.46 no.1
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• pp.143-155
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• 2018

The Natural Landscape Rating System was introduced in the amendment of the NATURAL ENVIRONMENT CONSERVATION ACT in 2006. For landscape preservation, the system aims to consider the effects of development projects or plans implemented in a natural landscape on skylines, scenic resources, and view corridors. Currently, a lack of consistency in standards for determining Landscape Control Points (LCP) to assess landscape impact lowers the accuracy and reliability of the assessment results. As the perception of and the impact on a landscape varies, depending on the location of the LCP, it is necessary to establish a reasonable set of criteria to select viewpoints and avoid unreliability in the assessment due to unclear criteria. The intent of this study is to propose an objective and reasonable set of criteria for LCP selection to effectively measure the impact on the landscape from development projects that anticipate a change in the landscape and, ultimately, to suggest basic analysis methods to assess the landscape impact of development projects and to monitor the landscape in the future. Among the development projects affecting natural landscapes, as reported in the statement of the environmental impact assessment, cases of construction of a single building or other small-scale development projects were studied. Four spot development projects were analyzed in depth for their landscape impacts, in order to make recommendations for the LCP selection procedure, which aims to widen the scope of selection according to the direction of viewpoints from the target site. The existing results of analysis based on LCP have limitations because they failed to cover the viewshed of the target buildings when there are topographical changes in the surroundings. As a solution to this problem, a new viewshed analysis method has been proposed, with a focus on the development site and target buildings, rather than viewpoints, as used in past analysis.

• Magazine of the Korean Society of Agricultural Engineers
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• v.24 no.4
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• pp.57-68
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• 1982

The paddy fiels slope located in Kangweon province Hwyongsung gun Gonggeun myon Shinchonri was considerably steep and so it was impossible to economically consolidate the field up to date. But for the porpose of farm mechanization, the field (32. 27ha) was consolidated by the auther under the assitance of the Ministry of Agriculture and Fishery and,;the Administration of Kangweon province. This paddy field consolidation was caused by the treatise on "Land-consolidation methods for farm mechanization in the steep-sloped paddy field", of which the auther is the same. The constrution was carried out from September, 1981 to April, 1982. During the 4esign and construction, some Peculiarities were found and discussed. That is, in design, besides the common condititions for a design, some special conditions were considered and written below; (1) The ranges of field slope in this design were 1/100-1/30. (2) Long sides of the land readjustment blocks must be arranged abreast contour line, and so they make the amount of cutting and banking decreased so as to take the maximum advantage of the configuration of the field. (3) In design, the main principles of dividing blocks were written below; i) First of all, long side of a block should be drawn straight abreast a contour line. ii) Long side of a block should arrange abreast contour line and make its length 100-150m, if not, l)reak the side in order to make a bended rectangle. iii) Length of a short side should be determinded within differences of elevation (0.6 -1. 2m) between the two adjacent blocks toward the normal to a contour line. iv) Length of a short side should be above 15m and the ratio of long and short side should be slso kept 1: (4-6). v) A new field surface leveling was determinded from the elevation which produce the least amount of cuttingand banking within the range of 0.6-1. 2m diffe rences of elevation between the two adjacent blocks. vi) In the course of dividing blocks with the same width along the line which was normal to a contour line, all blocks connot keep their shape in a retangle because of steep slope of the field and so on, and so it was also necessory to make some non-retanglar and small blocks such as a trianglar or trapezoidal shape, which was impossible to use some of farm machinery. But because this non-rectanglar and small blocks were divided, larger and many rectanglar blocks can be divided and construction cost can also be lowered. According to the conditions discussed above, the paddy field consolidation project designed and constructed. And the results of this study were obtained as below; (1) Three-forth of total cost of this paddy field consolidation was not construction cost, and these cost consist of land grading (1/4), road and canal construction cost (1/4) and the other cost (1/4) such as surveying or materials and 56 on. (2) The steeper the land slope, the greater cost was assigned for road and canal construction, and than land grading. (3) Curtailment of the road and canal construction cost depended on simplificating their strutures. (4) In the case of the land slopes were low, the land grading cost was high by 1: 1.4 in comparison with the road and canal construction cost, and conversely when the slops were steep, the road and canal construction cost was high by 1 : 5 in compa- rison with the land grading cost. (5) The densities of irrigation canal, drainage canal and trunk and branch road were 150. Sm/ha, 60. im/ha and 17. 4m/ha respectively. The density of irrigation canal of the area was high by 2 times in comparison with the average one of Kangweon Province, and the others were nearly the same. (6) Most farmers (above 85%) knew the effects of paddy field consolidation. The effects are; 1) Improvement of irrigation 2) Improvement of farm management 3) Improvement of transportarion 4) farm mechanization and 5) grouping of the scattered land. And the more farm modernization was accomplished by these projects, the more farmers wanted to live in their land. (7) In spite of the very steep sloped paddy field, the diminution rate of the net farm land caused by consolidation was 7.7% which was nearly the same as the one of Chulweon plain of Kangweon province. Land grading cost was 971, OOOwon/ha which was rather cheap by 13.2% than the one of Ghulweon plain, and unit construction cost was 5, 341, OOOwon/ha (included soil addition) which was also nearly the same as the one of Chulweon plain and FNFIA (The federation of national farmland improvement association).

• Journal of Digital Convergence
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• v.16 no.6
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• pp.75-84
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• 2018

Although many logistics companies are interested in project logistics, the existing research has been limited to the growth potential of project logistics market and the high barrier and importance of project logistics. This study analyzes using DEA the operational efficiency of forwarding companies registered in major overseas construction EPC companies and performing logistics services for overseas plant construction projects. For efficiency analysis, Super-SBM analysis and Malmquist analysis are used among DEA analysis techniques. As a result of the Super-SBM analysis, DMU 5 ranked first at 1.807. DMU 5 is more efficient than the other large corporations because it has the stable supply of its parent company H and the smallest input and output variables among the large corporations. As a result of Malmquist analysis, TCI, which is a technological development, showed a fluctuation while TECI showed a relatively stable variation. In addition, there is a difference in scale between major companies and small and medium sized companies. So, it is necessary to identify the efficiency improvement strategy for each group and apply it to the practical work.

• Korean Journal of Construction Engineering and Management
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• v.14 no.4
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• pp.108-117
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• 2013

The domestic CM business market has continued to grow, but its size is relatively small yet in comparison with the total size of the domestic construction industry. Evaluation of CM projects was conducted through questionnaire surveys. Both clients and CM firms showed positive satisfaction levels. Nevertheless, the clients' satisfaction levels were relatively low in safety management, cost management, and document and information management. Superior areas of CM tasks were time management and recovery scheduling, quality control and technical instruction, and design value engineering. On the other hand, inferior areas of CM tasks were claim analysis and dispute resolution, cost estimation, and life cycle costing. Both entities have agreed with the positive effects of CM involvement in terms of cost saving, time reduction, quality improvement, and safety incidents prevention to at least 0~5% extent.