• Tunnel and Underground Space
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• v.31 no.6
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• pp.494-507
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• 2021

With the increasing use of TBM, research has recently been conducted in Korea to analyze TBM data with machine learning techniques to predict the ground in front of TBM, predict the exchange cycle of disk cutters, and predict the advance rate of TBM. In this study, classification prediction of rock characteristics of slurry shield TBM sites was made by combining traditional rock classification techniques and machine learning techniques widely used in various fields with machine data during TBM excavation. The items of rock characteristic classification criteria were set as RQD, uniaxial compression strength, and elastic wave speed, and the rock conditions for each item were classified into three classes: class 0 (good), 1 (normal), and 2 (poor), and machine learning was performed on six class algorithms. As a result, the ensemble model showed good performance, and the LigthtGBM model, which showed excellent results in learning speed as well as learning performance, was found to be optimal in the target site ground. Using the classification model for the three rock characteristics set in this study, it is believed that it will be possible to provide rock conditions for sections where ground information is not provided, which will help during excavation work.

• Korean Journal of Construction Engineering and Management
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• v.14 no.1
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• pp.12-22
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• 2013

Construction industry throughout the construction projects life cycle using BIM is able to manage information. Among them, BIM-based quantity take-off is directly connected to the data of the construction business as an important management element that is essential for one of the management factors of feasibility study and economic analysis. In addition, the result of BIM-based quantity take-off can be varied depending on modeler, so the exact guideline for BIM modeling is necessary. The BIM-based quantity take-off in terms of reliability and accuracy of the information is very important. Therefore, this study verified the BIM modeling of the apartment interior materials using both separate object and composite object was validated the quantitative comparison of the difference in BIM-based quantity take-off for accuracy & reliability judgment of BIM-based quantity take-off and realistic & desirable suggestion of BIM modeling way. As the result of this study, it is preferable to model various interior materials to use separate object for the purpose of correct BIM-based quantity take-off, but the realistic way of the BIM modeling using both separate object and composite object jointly was verified in order to judge BIM-based quantity take-off in terms of work productivity.

• Journal of the Korea Concrete Institute
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• v.20 no.2
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• pp.249-256
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• 2008

With consideration of the ongoing construction of high-rise buildings, it is becoming increasingly important to be able to accurately predict the behavior of them on the stage of design, construction and service. Even though many researchers have developed the analysis method to predict the behavior of high-rise buildings, their studies were based on the two dimensional frame structures composed of line elements such as beams and columns. Recently the high-rise buildings with flat-plate system is widely used because of its advantages. In this study a three dimensional analysis method is developed to analyze the behavior of the high-rise buildings with flat-plate system since it is difficult to model the structural systems reasonably with the existing two dimensional analysis method. The analysis method considered the construction sequence including the temporary work such as installation of form, removal of form, installation of shore, and removal of shore. Line elements were used to describe columns, beams, and shores and plate elements were used to model slabs. The creep and drying shrinkage of concrete were also considered to account for the inelastic behavior of concrete.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.34 no.6
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• pp.417-426
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• 2021

Recently, use of the precast concrete (PC) system, which can increase economy by minimizing field work, has rapidly increased. However, the PC system cannot exhibit structural performance under construction, specifically before integration between members. Furthermore, since it is difficult to secure the structural integrity of beam-column joints even after construction, the PC system is vulnerable to progressive collapse. In the PC system, various types of details for PC beam-column joints have been proposed, while the structural/construction details of PC system generally used in Korea differ from those of overseas PC systems. However, studies on the progressive collapse of the domestic PC system are limited. Thus, in this study, we investigated the structural/construction details of PC beam-column joints mainly used in Korea. Based on the investigation, for the prototype PC system with typical joint details, a nonlinear finite element analysis was carried out to evaluate its structural performance under progressive collapse. Further, a parametric study was performed, and the effect of the design parameters was investigated, to recommend a method to improve the progressive collapse resistance of the PC system.

• Journal of the Korean Institute of Landscape Architecture
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• v.44 no.4
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• pp.45-56
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• 2016

In this study, an analysis has been conducted on the evaluation criteria of current G-SEED(Green Standard for Energy and Environmental Design) and on the 78 buildings, certified by G-SEED, for 3 years from November, 2012 to November, 2015. Based on the results of this analysis, four issues are driven and proposed hereinafter. Issue 1 : Nowadays, the psychological proportion of landscape architecture in building is getting greater than ever so that it shows reliable reduction of carbon dioxide. Therefore, so far as the eight kinds of buildings are concerned, the evaluation items of G-SEED must include those of landscape architecture mandatorily through its enlargement. Issue 2 : It is undesirable factor that inhibits precise evaluation on landscaping area to let other areas appraise landscape architecture because it requires outstanding professionalism. So, G-SEED should not only ensure landscaping professionalism for the correct evaluation but also let landscape area participate in assessing other areas. Issue 3 : Many previous researches turned out that landscape planting technique has excellent effect on saving energy and reducing temperature of buildings. Thus, landscape planting technique of landscape area is required to be one of the evaluation items of energy sector. Issue 4 : Tree management also has to be newly included as one of the evaluation factor for the maintenance relating to the landscape architecture. G-SEED, enacted and enforced by the Green Building Creation Support Act in 2013, surely is effective system to reduce carbon dioxide in buildings. This is a special Act in its nature that is superior to Construction Law and must be observed by all means to construct buildings. Under the umbrella of this legal system, various of researches and products are contributing to creating new jobs in construction area. However, it is a well-known fact that landscape architecture area has shown less interest on this Act than that of construction area. In conclusion, it is necessary that landscape industry should conduct continuous researches on G-SEED and pay more attention to the Act enough to harvest related products and enlarge its work area.

• Journal of KIBIM
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• v.1 no.2
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• pp.19-23
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• 2011

The planning stage of an architectural project has much more significant effects on the cost or outcome of the project than other stages of the project. In addition, the importance of architectural planning has been further increasing according to the recent trend of construction projects becoming larger in scale and more complex. In spite of this, the current situation is that the planning stage work is not being systematically managed. Accordingly, the purpose of this study was to develop a BIM-based simulation system for providing support during architectural planning stage such as spatial planning & review, cost review, project owner requirements management, etc. It is easy to review various alternatives using this system that allows not only the modeling of space object modeling but also the instantaneous review of spatial area & layout, cost, etc. based on object information. In addition, it can be used as a communication tool with the project owner as it provides the visualized information and quantitative data of the building model, and the information created through this system can be delivered to the following stage for usage. It is thought that using this system, the entire project work including the architectural planning stage can be supported and even contributing to the advancement of architectural process.

• Explosives and Blasting
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• v.27 no.1
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• pp.62-78
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• 2009

Recently, construction techniques have been rapidly developed with reconstruction of old buildings, urban regeneration and efforts of restoring natural ecology, so demolition of deteriorated buildings has been rapidly increasing. Demolition work of building should be executed without damaging surrounding environments according to relevant regulations. There are various demolition methods and among them, explosives demolition is the most practical way for expenses and safety of work. As a part of Daejeon stream ecological restoration project, this thesis is a case of executing demolition of Chung-Ang Department Store which was built 35 years ago as covered structure on the upper part of Daejeon stream with explosives demolition. This structure is 8 stories high, total height of 41.6 m including basement floor, $1,650m^2$ for building area and $18,351m^2$ for total floor area. It is located in the center of Daejeon city where shopping centers and buildings are crowded and main facilities are Daejeon subway (18m), backside shopping center (20m), underground shopping center(15m), Mokchuk bridge, Eunjung bridge(0.25m) and fiber-optic cable(0.25m). In this project, implosion was selected for explosives demolition methods by considering this area being a busy urban area, and this project was executed after examining collapse movement of structure in advance using simulation program not to damage main facilities. Total 80kg of explosives and 1,000 detonators were being used. This project will be a good case of executing explosives demolition successfully by applying implosion on urban area in the country.

• Journal of the Korean Home Economics Association
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• v.31 no.1
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• pp.225-239
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• 1993

The purpose of this study is to look for the basic formative elements of housekeeping space of our cultural life which are worthy to succeed and develop by revaluating in modern view and to reveal what we should maintain form the women's view of the housework in those days. In this study, out look on Chosun Dynasty housekeeping is based on the norm of the women in those days. The research on the housekeeping space for norm of the women in those days. the research on the housekeeping space for Chosun Dynasty upperclass is focused on the house built from early till late Chosun Dynasty, which is now a cultural asset. As a result, norm of Chosun Dynasty have created a social wide atmosphere for women to devote herselves to the housekeeping. Moreover the constructions of Chosun Dynasty's upperclass are affected by Korea's natural environment and socio-cultural environment. Primary factors for natural environment are building materials and the change of seasons. Because of changeable seasons, there were places for storing massive commodities. The other primary factors for socio-cultural environment affecting housekeeping space were social positions, and extended family system, worshipping the ancestors standard of living, the theory of“Poong Soo”(風水, a kind of geomancy) and thought of“Yin and Yang, Five Elements”(陰陽五行) and popular belief of that time. Affected by these two environments, the characteristics of housekeeping space for Chosun Dynasty are ; the main building of the house was used as a diverted area for women to work, and was reconstructed for household affairs. There were inefficient points in the housekeeping space of that time and the space remained stagnant because of the restricted sex and the social position of housekeeping doer. But you could find some points that are efficient and functional to adjust in those living conditions. The storehouse, storage barn, shed and soyjar terrace are the specialized storing place, according to the kinds and characteristics of the commodities. the kitchen, for example, is the combinations of many abilities. It is not only for cooking or heating the room, but also for storing drinking water. The hall which was the storing place, housekeeping place and also the place for family events are used as a diverted place. The linked arrangement of kitchen, store house, boudoir and the other rooms. In addition, we can see that the construction of the kitchen for more than tow people could work in.

• Journal of the Korea Institute of Building Construction
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• v.16 no.5
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• pp.421-428
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• 2016

In this work, pozzolanic activities of various waste materials were compared with those of well-known by-product pozzolanic materials. Undensified and densified silica fume, ASTM class F and class C fly ash, and metakaolin were chosen as well-known pozzolanic materials, and bentonite powder, ceramic powder obtained from wash basin, and waste glass wool, which can possibly possess pozzolanic property, were chosen for comparison. Drop in electrical conductivity at $40^{\circ}C$ saturated lime solution was measured for each materials. The amount of Ca(OH)2 decomposed from cement paste at $450{\sim}500^{\circ}C$ was also measured to evaluate pozzolanic activity. The 28 day compressive strength were used to observe the mechanical property enhanced by incorporation of various waste materials. According to the experimental results, using "difference between maximum conductivity value and conductivity value at 4 hour" was found to be a reasonable approach to determine pozzolanic activity of a material. Pozzolanic activity measured using electrical conductivity correlates very well with that measured using the amount of Ca(OH)2 remained in the cement paste. Relatively good agreement was also found with electrical conductivity and 28 day compressive strength. It was found that electrical conductivity measurement can be used to evaluate pozzolanic activity of unknown materials.

• Journal of the Korea Institute of Building Construction
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• v.18 no.5
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• pp.403-412
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• 2018

Recently, needs for utilization of recycled aggregate have been increasing. However, its utilization has been limited due to its high alkalinity, which mostly came from the unremoved cement paste particles that were attached at the surface of recycled aggregate. Various efforts has been made to reduce its alkalinity by using $CO_2$, but currently available methods that uses $CO_2$ generate the problem with pH recovery. Considering the fact that supercritical $CO_2$ ($scCO_2$) can provide more rapid carbonation of cement paste than by normal $CO_2$, $scCO_2$ was utilized in this work. The reaction between $scCO_2$ and hydrated cement paste has been systematically evaluated. According to the results, it was found that powder type showed higher carbonation compared to that of cube specimens. It seems the carbonation by $scCO_2$ has occurred only at the surface of the specimen, and therefore still showed some amount of $Ca(OH)_2$ calcium aluminates after reaction with $scCO_2$. With powder type specimen, all $Ca(OH)_2$ was converted into $CaCO_3$. Moreover, additional calcium that came from both calcium aluminate hydrates and calcium silicate hydrates reacted with $scCO_2$ to form $CaCO_3$. After carbonation with $scCO_2$, the powder type specimen did not show pH recovery, but cube specimens did show due to the presence of portlandite.