• Journal of the Korea Institute of Building Construction
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• v.15 no.3
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• pp.265-271
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• 2015

This study is intended to produce a PC (Precast Concrete) member without a steam curing process in developing the high early strength concrete satisfying the condition of 10MPa in compressive strength at the age of 6 hours, and is intended to ensure economic feasibility by increasing the turnover rate of concrete form. Hence, high early strength cement with high $C_3S$ content and the hardening accelerator of powder type accelerating the hydration of $C_3S$ was used. And the properties of concrete were evaluated according to the hardening accelerator mixing ratio (0, 1.2, 1.6, 2.0). No big difference was found from the tests of both slump and air content. When 1.6 % or higher amounts of the hardening accelerator were mixed, the compressive strength of 10MPa was achieved at the age of 6 hours. From the test results of autogenous (drying) shrinkage and plastic shrinkage, it can be seen that there was a difference according to hydration reaction rate due to the addition of the hardening accelerator. However, it was shown that no problem arose with crack and durability. And it was shown that resistance to freezing-thawing, carbonation, and penetration were excellent.

• Korean Journal of Construction Engineering and Management
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• v.10 no.5
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• pp.67-75
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• 2009

While the trend of all industries recently lies in combination, construction industry is much interested in enhancing efficiency and competitiveness in the aspect of site control by adopting RFID. Though RFID has been applied to diverse areas thus far, it cannot be easily applied to construction industry due to diverse physical, chemical and use-environmental properties of construction materials. Furthermore, it is rarely applied to the site because of many problems in its application. It is required to prepare RFID code issuance and system that can systematically control the code as well as to research the standardization of frequency, specification, protocol, package method, recognition method, etc in order to apply RFID to construction industry. In this research, RFID code issuance and management program are proposed as a part of program research to apply RFID. Furthermore, the restricted matters of existing RFID tag are drawn to produce pilot product of RFID tag that can solve it so as to perform site application test. According to the experiment, effective recognition distance varies depending on material/environmental property and control efficiency changes depending on attachment method and application method. Thus, preparing diverse restrictive factors and solutions by systematically analyzing control method(medium, process) of current architecture materials and applying it to construction site can be the way to successfully apply RFID.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.16 no.11
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• pp.7617-7628
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• 2015

Recent changes in the industrial parks have become a major issue in the nation's economic aspect. However, the industrial park's structure-advance projects under regional changes have excluded the surrounding spaces. The purpose of study is to analyze physical characteristics of Industrial park and adjacent area and to propose practical urban linkage alternatives as place-making It was found that in an urban aspect, the industrial parks belong within the city, but look like an isolated island that doesn't belong to a city. Therefore, as a way that could improve the problems above, and prevent the formation of heterogeneous spaces, the deliberate management of Industrial park's structure-advancement projects is needed. As one of these measures, It is concluded that the review of designating industrial facility zones which is a district unit plan and managing the detailed elements of construction to the various elements of the district level are needed.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.18 no.6
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• pp.22-30
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• 2004

It is an attempt to suggest the standard valuation method of the environmental illumination for the bridges across the Han-river from an aesthetic point of view, deviating from the technical and traditional viewpoint. In Korea the current evaluation criterion to verify the value of bridge design has a partiality for the technical and structural safety rather than the sentient beauty on the whole. However, the recently cultural reform of Korean mass society with the elevation of the standard of living forces the engineering designers for bridges to focus not only on competing physical structures but also on enhancing the formative beauty including the illumination effects for night view. Additionally, the new policy, which transforms the environments around the Han-river into the major tourist attractions has been executing strongly by the city authorities to revitalize the symbolic, historic, and cultural identity of the capital city with the introduction of the high-quality environmental illumination for the bridges. As a result, It becomes necessary to establish the manual and standardization of the environmental illumination planning for the city in terms of the formative beauty, and this study is to suggest the valuation model method of the environmental illumination for the bridges as the initial step of the standardization. In the study, the valuation items of the standard questionnaire are selected by the documentary records and the consultation of various experts in architecture, design, fine art, urban planning and even administration to verify the essential elements of the aesthetic beauty with the local amenity and the environmental harmony for the chosen bridges across the Han-river.

• Journal of KIISE
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• v.42 no.5
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• pp.591-600
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• 2015

SLA (Service Level Agreement) is an essential factor that must be guaranteed to provide a reliable and consistent service to user in cloud computing environment. Especially, a contract between user and service provider with SLA is important in an environment using a cloud service brokerage. The cloud computing is classified into IaaS, PaaS, and SaaS according to IT resources of the various cloud service. The existing SLA is difficult to reflect the quality factors of service, because it only considers factors about the physical Network environment and have no methodological approach. In this paper, we suggested a method to specify the quality characteristics of software and proposed a mechanism and structure that can exchange SLA specification between the service provider and consumer. We defined a meta-model for the SLA specification in the SaaS level, and quality requirements of the SaaS were described by the proposed specification language. Through case studies, we verified proposed specification language that can present a variety of software quality factors. By using the UDDI-based mediation process and architecture to interchange this specification, it is stored in the repository of quality specifications and exchanged during service binding time.

• Journal of the Korea institute for structural maintenance and inspection
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• v.24 no.3
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• pp.63-69
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• 2020

The volume of construction waste material from the entire waste material volume in Korea is approximately 47.3% to take the biggest ratio, and from them, the waste concrete takes up approximately 62.8% that recycling is an urgent issue to address. Therefore, the government recommends more diverse and broader facilitation of the recycled aggregate in order to promote recycling the construction waste materials. In addition, when using concrete recycled aggregate in building, building standard such as floor area ratio and building height are being mitigation. The standard is a condition that mitigation the floor area ratio by up to 15% when using up to 25% of concrete recycled aggregate. Therefore, this study reviewed the relaxation of construction of construction standards when using concrete recycled aggregate in order to actively recommend the use of concrete recycled aggregate. And using the recycled coarse aggregate among the recycled aggregate, the appropriate mixing time in the batch plant according to the substitution rate was derived. In addition, using recycled aggregate admixture in order to improve the drying shrinkage, did comparative analysis about physical and mechanical property of concrete.

• Journal of the Korea institute for structural maintenance and inspection
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• v.24 no.3
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• pp.96-103
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• 2020

As a basic study for the application of natural zeolite as a concrete admixture, the compressive strength, activity factor, Ca(OH)₂ quantitative analysis and XRD experiments were investigated. It is thought that SiO₂, which is abundant in natural zeolite, affects the strength development by reacting with the hydration product of cement in all specimens in which natural zeolite was added according to powder level and substitution rate. As the substitution rate increases, the compressive strength decreases, which is considered to be due to the decrease in the amount of C₃S and C₂S minerals in the clinker, which affects the strength expression compared to the cement content of the reference mortar. The XRD crystal structure did not show a significant difference from the reference mortar, and it was confirmed that the Z2-10 (Blaine: 15,600㎠ / g) specimen with 10% substitution of natural zeolite was the best among the experimental levels. Substitution amount for use as concrete admixture is 10% substitution is most ideally seen.

• The KIPS Transactions:PartA
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• v.8A no.4
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• pp.479-488
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• 2001

As the SoC designs complexity constantly increases, the simulation that uses their software models simply takes too much time. To solve this problem, FPGA-based logic emulators have been developed and commonly used in the industry. However, FPGA-based logic emulators are facing with the problems of which not only very low FPGA resource usage rate due to the very limited number of pins in FPGAs, but also the emulation speed getting slow drastically as the complexity of designs increases. In this paper, we proposed a new innovative emulation architecture and its software that has high FPGA resource usage rate and makes the emulation extremely fast. The proposed emulation system has merits to overcome the FPGA pin limitation by pipelined ring which transfers multiple logic signal through a single physical pin, and it also makes possible to use a high speed system clock through the intelligent ring topology. In this topology, not only all signal transfer channels among EPGAs are totally separated from user logic so that a high speed system clock can be used, but also the depth of combinational paths is kept swallow as much as possible. Both of these are contributed to achieve high speed emulation. For pipelined singnals transfer among FPGAs we adopt a few heuristic scheduling having low computation complexity. Experimental result with a 12 bit microcontroller has shown that high speed emulation possible even with these simple heuristic scheduling algorithms.

• Korean Journal of Soil Science and Fertilizer
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• v.44 no.5
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• pp.944-958
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• 2011

Soil hydraulic properties such as hydraulic conductivity or water retention which are costly to measure can be indirectly generated by soil pedotransfer function (PTF) using easily obtainable soil data. The field soil structure description which is routinely recorded could also be used in PTF as an input to reduce the uncertainty. The purposes of this study were to use qualitative morphological soil structure descriptions and soil structural index into PTF and to evaluate their contribution in the prediction of soil hydraulic properties. We transformed categorical morphological descriptions of soil structure into quantitative values using categorical principal component analysis (CATPCA). This approach was tested with a large data set from the US National Pedon Characterization database with the aid of a categorical regression tree analysis. Six different PTFs were used to predict the saturated hydraulic conductivity and those results were averaged to quantify the uncertainty. Quantified morphological description was successively used in multiple linear regression approach to predict the averaged ensemble saturated conductivity. The selected stepwise regression model with only the transformed morphological variables and structural index as predictors predicted the $K_{sat}$ with $r^2$ = 0.48 (p = 0.018), indicating the feasibility of CATPCA approach. In a regression tree analysis, soil structure index and soil texture turned out to be important factors in the prediction of the hydraulic properties. Among structural descriptions size class turned out to be an important grouping parameter in the regression tree. Bulk density, clay content, W33 and structural index explained clusters selected by a two step clustering technique, implying the morphologically described soil structural features are closely related to soil physical as well as hydraulic properties. Although this study provided relatively new method which related soil structure description to soil structure index, the same approach should be tested using a datasets containing the actual measurement of hydraulic properties. More insight on the predictive power of soil structure index to estimate hydraulic properties would be achieved by considering measured the saturated hydraulic conductivity and the soil water retention.

• Asia-pacific Journal of Multimedia Services Convergent with Art, Humanities, and Sociology
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• v.9 no.7
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• pp.707-722
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• 2019

The concept of neighborhood parks has been used as the principle of forming a community in our society going through modern and contemporary times. The concept of neighborhood parks equipped with physical facilities has been discussed constantly regarding the roles and meanings of them. This study focuses on pocket parks which have been playing roles in improving environment through regeneration and forming regional communities based on that as neighborhood facilities. This author carried out field investigation on total 72 Hanpyeong Park and Hanpyeom Parks formed in the capital area and examined the significance of planning them and also their utility and residents and users' attachment to them through a survey. In this process, this researcher has been able to draw following conclusions. First, according to the demographic characteristics of users, there is significant difference found by groups in terms of their place attachment to the parks. This implies that difference in the major types of residences supplied these days influences their intention to experience ecological space. Second, according to their educational background, there is significant difference found by groups regarding their place attachment to the parks. Third, according to user behavior, there are differences found in their place attachment to the parks and also detailed differences found by groups in terms of the frequency of use and duration of stay.