• Proceedings of the Korean Institute Of Construction Engineering and Management
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• 2004.11a
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• pp.531-534
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• 2004

Cutting work of the concrete pile is an important task to chsh a part of pile head which is compressed with more than $800kgf/cm^{2}$. It is usually performed by a crusher and three to four skilled workers. llecent analysis results of the pile cutting work reveal that it frequently makes a lot of cracks which significantly reduce the strength of the pile and is labor-intensive work. The primary objective of this study is to propose the end-effector which can effectively break PHC Pile without any longitudinal cracks before developing an automated pile cutting machine having unified grinder and crusher parts. It is anticipated that the development of the automated pile cutting machine would be able to bring improvements in safety, productivity, quality as well as cost saving.

• Proceedings of the Korean Institute Of Construction Engineering and Management
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• 2004.11a
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• pp.256-260
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• 2004

As a large portion of defence budget are alloted for military facility construction, reasonable budget estimation in the planning stage has been officers' main concerns. However the proper estimation of construction cost is difficult to be carried out due to the absence of systematic criteria. To improve the budget estimation for military facility construction, this study proposes a cost index model which can convert historical cost to current cost. Thus the developed cost index would enhance effectiveness of budget estimation process 3nd support reasonable decision making. This cost index model is developed by analyzing historical cost data with statistical methodology The study is executed by following process. First, factors which affect construction cost for the most are selected by analyzing historical cost data. second, the selected factors are categorized material cost, labor cost and equipment cost, and weights of those factors are calculated by dividing the cost of each factor by total item costs. Last, cost index is developed by using weighted average method.

• Proceedings of the Korean Institute Of Construction Engineering and Management
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• 2004.11a
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• pp.579-583
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• 2004

A new and extendable highway should be planned and budgeted by estimating the total construction cost on the basis of the precise cost data. However, the demolition or disjointing cost could not reflect construction site condition sufficiently because it was simply estimated by multiplying the highway structure installation cost by the regular ratio($10\~70\%$) specified in the Korea Standard Estimate. The regular ratio for estimating of demolition and disjointing cost was calculated by not actual construction cost data but subjective experiences of field manager. Therefore, the reliance of the estimated demolition or disjointing cost has been declined. The primary objective of this study is to purpose the standard for estimating proper demolition or disjointing cost of relevant items through various site analysis and survey, and to investigate on the propriety of ratio-unit price method for estimating demolition and disjointing cost.

• Korean Journal of Construction Engineering and Management
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• v.12 no.6
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• pp.120-129
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• 2011

An installation of the construction lift has a few limitations by many constrains and these have influences on labor productivity, that can be changed by vertical-transportation management. In the super-tall building construction, a management of construction lift operation is one of the most important factor, but existing methodologies depend on skilled practitioners' experiences. And it is true that the expertise resulted by the experiences does not transfer to the next generation. This study is a part of lifting-management simulation development which aims at the optimal construction lift management. A proposed algorithm is focus on lifting time calculation considering an acceleration capability. This research evaluates the result accuracy using comparative analysis on simulation result and field measuring time.

• Korean Journal of Construction Engineering and Management
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• v.12 no.5
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• pp.103-116
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• 2011

Crack sealing is a maintenance technique commonly used to prevent water and debris penetration and reduce future degradation in pavement. In recent years, several systems for automatically routing and sealing pavement cracks have been developed in the highway construction and maintenance area. Automating pavement crack sealing can improve safety, productivity and quality, and reduce road user cost as well. The reduction in crew size and the increase in productivity of the automated sealing process will be translated directly into significant potential cost savings. The main objective of this study is to illustrate conceptual models for the development of the automated pavement crack sealer which meets domestic road condition and regulation, and to discuss its technical feasibilities. Conclusions are made concerning the applicability and the value of cantilever-typed pavement crack which is selected as the most feasible alternative in both economical and technical aspects.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.33 no.4
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• pp.1707-1718
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• 2013

Historical cost data estimating system has been introduced since 2004 in the construction industry. Based on contract prices of past projects, this estimating system estimates construction cost according to work types. The Korea Institute of Construction Technology (KICT) announces the historical cost data twice a year annually. The unit price of a small construction project is higher than large construction project due to the increase on production cost per work unit, equipment and labor cost, etc. However, the historical cost data estimating system is applied to project estimation uniformly regardless the construction project's size. This study compared and analyzed the historical cost data of large and small construction project to indicate the problem of historical cost date estimating system. The study derived that the unit price of a small construction project is 21.8% higher than that of large construction project.

• Journal of Korea Society of Industrial Information Systems
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• v.5 no.1
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• pp.77-86
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• 2000

Even manual materials handling tasks(MMHT) is decreasing by adopt of automatic manufacturing system & transportation supporting machine because of increase of productivity, wage lack of labor, safety, in fact working at inclined & complicated slope such as farm, orchard, harbor loading & unloading, logging place and mining place can't be substituted by machine perfectly. So, workers should do MMHT at this place by themselves, lifting on slope can cause much of hazard, include falling. Keeping balance net to slip can be a reason of low back pain(LBP) by overloaded musculoskeletal system but, there's no enough study about lift on slope. Therefore, In this study, we assessed and analyzed change of center of pressure(COP) when lifting on slope by force platform. The result showed that the length lengthen as increasing angle of slope. Especially, the length extremely increased over 15°. Through These basic result, present proper angle boundary, prevent industrial accidents and give proper data not only lifting but also pushing and pulling on slope someday.

• Korea journal of population studies
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• v.28 no.1
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• pp.277-311
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• 2005

본 연구는 여성이 가족과 일을 병행하려 할 때 안게 되는 이중부담의 양과 유급노동시간과 무급노동시간에 영향을 주는 변수들의 차이를 통해 남성과 여성의 시간사용구조를 살펴보고, 이중부담이 노동시간양${\cdot}$노동시간대${\cdot}$노동장소로 나타나는 여성 유급노동시간에 미치는 영향을 알아보았다. 자료는 통계청의 1999년 생활시간조사 원자료를 이용하였다. 분석결과 맞벌이 가구의 여성은 남성보다 하루 평균 1시간 51분 많은 총노동시간을 가지면서 주당 약 13시간의 이중부담을 가지고 있었다. 이것은 만성과 여성의 노동시간사용구조가 서로 다르기 때문이었다. 즉, 여성은 경제활동에 참여한다할지라도 무급노동시간의 89%를 책임지고 있었으며 여성의 노동시간은 가족상황에 의해 영향을 받는 젠더화된 생활시간사용구조를 가지고 있었다. 또한 기존연구결과와 다르게 가내하청/재택근무, 자영, 무급가족종사와 같은 종사상지위와 미취학자녀의 존재는 여성에게 유급노동시간을 조절하는 기재가 되지 못했고 무급노동시간을 늘리는 역할을 할 뿐이라는 점이 한국사회 여성의 이중부담을 가중시키고 있는 것으로 보인다. 또한 맞벌이가구 여성은 무급노동에의 일차적 책임으로 남성보다 야간유급노동이나 휴일유급노동시간을 줄이고, 단시간노동을 선택하며, 집안에서의 유급노동시간을 길게 하면서 가족생활시간을 확보하는 유급노동시간 조절전략을 사용하고 있었다. 이러한 노동방식은 노동시장에서 여성노동의 불안정성을 만들어내고 주변화시키는 요인이다. 그러나 또 한편으로 서구사회와 비교하면 한국사회에서 여성이 경제활동을 하기 위해서는 광범위한 야간노동과 휴일노동, 장시간노동이라는 남성적 노동조건을 받아들이고 있는 것으로 보인다. 특히 판매/서비스직의 자영자와 무급가족종사자 여성들, 가내하청이나 재택근무를 하는 임금근로자 여성들, 학력이 낮은 기능/조립직과 단순노무직 여성들은 야간노동이나 휴일노동, 집안에서의 유급노동시간이 길뿐 아니라 절대적인 유급노동시간과 무급노동시간도 길게 나타났다. 그러나 미취학자녀의 존재가 이러한 여성적 유급노동시간의 특징에 영향을 주는 것은 아니었다.

• Korean Journal of Social Welfare
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• v.59 no.2
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• pp.143-169
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• 2007

The major purpose of this study was to offer a comprehensive analysis of the changing trends and causes of poverty among urban wage earners' households from 1995 to 2005. In order to do that, this study used the micro data of "Income and Expenditure Survey of Urban Households" by the National Statistical Office(NSO) and GEE(Generalized estimating equation) regression model which is know as an appropriate method for the longitudinal and clustering data. The results show that (1) the numbers of poverty rate and poverty gap in recent years are even getting seriously worse than those in the IMF crisis. (2) Main characteristics of poor are female headed, old aged, low educated households, and having atypical working position. (3) Major determinants of poverty are also related to the variables as mentioned the above. (4) However, poverty reduction effect of public transfer increased preferably in recent years.

• Journal of Korean Society of Forest Science
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• v.101 no.4
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• pp.729-736
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• 2012

Korea Forest Service is recently focused on forest tending works for promoting in green jobs. The purpose of forest tending work is not only maintaining ecologically stable forest stand structure but also developing commercial forest. These trends are also emphasized by creation of various benefits and expanding carbon absorption in forest management. For achieving these purposes, Management efficiency of output was analized by the inputs such as labor cost, material cost and expense cost using DEA technique. The results show that, 19 sub-compartments are appeared to be the optimal in the efficiency of the forest tending works among total 52 sub-compartments. Among those there were 5 sub-compartment 8-0-3, 9-3-3, 6-0-3, 7-0-6, 1-0-5 and 3-0-3 to be considered in the high reference. The high reference areas mean those areas which is well accomplished in forest tending works as the desirable model.