• Journal of Construction Engineering and Project Management
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• v.1 no.3
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• pp.28-37
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• 2011

Domestic construction companies are suffering from financing difficulties in the wake of the economic slump in Korea and abroad. During this economic slump, real estate investment trusts (REITs), facilitators for improving financing and stimulating construction businesses, have increasingly expanded since their introduction in 2001. However, in terms of growth speed and marketing size, Korean REITs are falling behind those of other nations. The purpose of this study is to suggest a method for composing a portfolio using the Markowitz portfolio selection model to stimulate REITs. The main contents are as follows. First, a comparative analysis was conducted of increased REIT profit with the application of the Markowitz model and the average REIT profit rate from July 3, 2007, to July 21, 2008, during the investment analysis periods. The results showed that the total profit rate from the Markowitz model was about 10% higher than the average REIT profit rate. Second, the sensitivity was analyzed according to the portfolio's data-gathering and replacement cycle to measure the optimum cycle and yield. The six-mouth profit data collection period showed about 16% higher profits with the Markowitz model than with the REITs. The two-week portfolio change period resulted in about 11% higher profits with the Markowitz model than with the REITs.

• Journal of the Korea Safety Management & Science
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• v.17 no.3
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• pp.33-44
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• 2015

Domestic plant construction sites have a tendency to become bigger, more various and complicated. Moreover frequency of industrial incident is increasing due to short project period, coexistence work condition and using heavy construction equipment. Installing safety facilities and safety training contribute to prevent incident. But mostly incident happens due to workers' unsafe action and wrong work method. Technically, it is very difficult for us to closely manage workers preventing incident. Therefore, the role of foreman who ordinarily works together with his workers is considered more important. Specific execution plan was drawn through industrial incident statistics from Ministry of Labor and questionnaire survey to interest parties(supervisor, safety staff and foreman). If foreman has raised sense of belonging and responsibility by conducting practical safety training for his workers, manages job site and receives proper compensation for these roles, it will be expected that it fully influences incident decrease.

• International conference on construction engineering and project management
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• 2022.06a
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• pp.525-532
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• 2022

Accidents at construction sites in Korea account for more than half of all industrial accidents. To solve this problem, a policy to strengthen safety education was implemented to ensure the safety of workers. However, it was analyzed that there is a high possibility of accidents because workers did not receive proper safety information for each risk factor due to general lecture-style education. In addition, statistics show that the accident status of workers with fewer years of period is high, indicating that a customized information delivery method needs to be proposed for unskilled workers with fewer years of period. Research on the importance of education has been conducted, but no information delivery method has been identified. For unskilled workers to effectively receive safety information, appropriate delivery formats (text, photos, illustrations, 4D-BIM, 360-based panorama, video, animation) were analyzed, and a new method of education was proposed. If customized safety information is provided according to this proposal, effective information delivery to unskilled workers will be possible, and it is expected to be verified in various ways.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2023.05a
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• pp.237-238
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• 2023

When primer is applied manually, adhesion performance decreases due to a decrease in primer penetration performance on the surface, and construction period delay may occur due to a long time due to a decrease in work efficiency when a large area is worked using a conventional roller. In addition, in the case of the roller method, precision work in corners and narrow spaces is not possible, so it is urgent to come up with measures to ensure uniform quality. In addition, secondary work occurs to remove fine powder from the surface before primer application, resulting in construction period delay due to the rise of the working stage. Therefore, in this study, equipment was used instead of manual work for primer work, and as a result, penetration performance and adhesion performance were improved about twice. From these results, it was confirmed that favorable results such as improving work speed, securing high quality, improving the working environment, and resolving the shortage of functional workers can be obtained.

• Journal of architectural history
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• v.25 no.2
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• pp.45-56
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• 2016

The purpose of this study is to analyze the evolutionary process of Ddeulzip. The subject of this study is a clan family of Andong Kwon in Andong Area. Ddeulzip's evolutionary process of the construction and management is divided into largely three periods in Josun Dynasty. The establishment and changing process of Ddeulzip for Andong Kwon's family are analyzed according to three periods called the early(15~16C), mid(17~18C) and late(19~20C). The characteristics of the early and mid period are that they created their own ancestral building form of Ddeulzip. Those of the late period are in their strong will to make similar scale of Ddeulzip. And during the late period, although the construction of new Ddeulzip was started in the early stage, no more formation of Ddeulzip was made as it approached toward the late stage. And most important point is similar constructional space(gan) of first time. The residential Ddeulzip of Andong Kwon's family created at the 19C can be regarded as an representative example of large space that shows a typical form of housing by noble residents at the time.

• Journal of architectural history
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• v.18 no.5
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• pp.25-39
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• 2009

The examples of developing a building site after the Woongjin period are mainly found in temple sites, tile-roofed building sites of unidentified features, and palace remains including the pavilion site with the river in the front(임류각지) inside the Castle of Gongsan, Gongjoo. In case of the Hanseong period, a glimpase of the features has gained in Poongnab mud castle and Mongchon mud castle, but the excavated relics are not yet enough to make some date out of them. After the Woongjin period of Baejae, the earth-ramming development method was used mostly to construct a building site, which is divided into horizontal and slant raising of the ground level. Both are used simultaneously, but there are the significant differences in the way of raising the ground level between them. Particularly, in case of the Wanggoong-ri relics in Iksan, the ground level was raised in a narrow line slantly, which is differentiated from other slant raising of the ground level, and its time of construction also is after that of others. In addition, the board-building development method used for narrow space is usually found in the remains since the seventh century. However, there are not enough the relics of Baekjae to reveal the whole aspect of building site development. It should be studied later through the subsequent excavation and research.

• Korean Journal of Veterinary Service
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• v.23 no.3
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• pp.263-269
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• 2000

This study was carried out to set a standard of damage compensation by researching state of damage due to noises in laying and prelaying hens. Recently, there are many damage cases in chicken farms near construction site that were caused by noises of construction. Therefore disputes and complaints about economical loss have increased ceaselessly. But we have few research and report such a thing. The result have shown that the weight loss rate was ranged from 9.48% to 23.2% and mortality of laying period of hens was higher than prelaying period. Pathological findings were fatty liver, congestion and hemorrhage of intestine, erosion of proventriculus and gizzard in order of case frequency. And these signs in hens of laying period was more serious than prelaying period. Half-life rate of antibody titers against Newcastle disease and infectious bronchitis in sound stressed hens was no different compared with non-stressed hens. Egg production rate dropped from 38% to 45% according to strength of noises. Before being stressed, hens produced special, large, middle, small-size eggs in the order. But after being stressed, their egg Production rate of middle, small-size Increased while egg production rate of special, large-size decreased. Production rate of soft and broken shell eggs was 0.015% in the stressed flocks higher than 0.005% in the non-stressed flocks.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2018.11a
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• pp.42-43
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• 2018

The research is to suggest the compensating strength values depending on various managing periods of concrete based on the strength development model calculated with equivalent age method for 20% of blast furnace slag replaced concrete. As a result, for 28 days of managing period, 9, 6, and 3MPa of compensating strength values were suggested when the temperatures were from 4 to 6℃, from 6 to 12℃, from 12 to 17℃, respectively. Additionally, for 42 days of managing period, 6 and 3MPa of compensating strength value was suggested when the temperature was from 4 to 7℃, from 7 to 12℃, and for 56 days of managing period, 3MPa of compensating strength value was suggested when the temperature was from 4 to 9℃. Furthermore, for 28, 42, 56, and 91 days of managing periods, any compensating strength values were needed when the temperature were higher than 17, 12, 9, and 4℃, respectively.

• Earthquakes and Structures
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• v.22 no.3
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• pp.263-275
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• 2022

Structural collapses can occur as a result of a dynamic amplification of either, the building's seismic response or the ground shaking by local site effects; one of the reasons is a resonance effect due to the proximity of the structural elastic fundamental period TE and the soil fundamental period TS. We evaluate the vulnerability to resonance effects in Guadalajara, México, in a three-step schema: 1) we define structural systems in the building environment of western Guadalajara, in terms of their construction materials and structural components; 2) we estimate TE with different equations, to obtain a representative value in elastic conditions for each structural system; and, 3) we evaluate the resonance vulnerability by the analysis of the ratio between TE and TS. We observe that the larger the soil fundamental period, the higher the resonance vulnerability for buildings with height between 17 and 39 m. For the sites with a low TS, the most vulnerable buildings will be those with a height between 2 and 9 m. These results can be a helpful tool for disaster prevention, by avoiding the construction of buildings with certain heights and structural characteristics that would result in a dangerous proximity between TE and TS.

• International conference on construction engineering and project management
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• 2005.10a
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• pp.952-955
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• 2005

In the early 90's, we had serious shortage of construction engineers in Korea. The shortage was acute especially in construction quality control and supervision area, which were gaining social attention due to the road bridge and the department store collapse that took the hundreds of lives in the early 90's in Seoul, Korea. In order to meet the high demand of construction engineers, the engineering license regulations were changed in 1995. Engineers who did not pass the written exam but have equivalent working experience are given engineering license to practice engineering legally. Since year 2000, while the severe engineer-shortage has been resolved, the opposite situation has occurred: there is serious over-supply of construction engineers. Policy makers and engineering practitioners are agreed to bring back the old-fashioned written exam engineer licensing system like before 1995, i.e., no more written exam exemption. However, the engineers who obtained license without taking written exam may not want to go back to old policy which would take their license. It is required to provide appropriate grace period before the new policy takes effect to minimize the impact of the changes. This paper forecasts the supply-demand of construction engineers providing the basis for the most appropriate policy changes.