• Korean Journal of Construction Engineering and Management
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• v.17 no.2
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• pp.31-38
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• 2016

In a construction project, the portion for maintenance costs for a building is considerable compared to the initial construction cost. As such, Life Cycle Cost (LCC) analysis is being increasingly utilized to assess the design value of engineering work in Korea. Additionally, the Public Procurement Service in Korea announced that it will be mandatory for all domestic construction projects to adopt BIM. Furthermore, the paradigm for architectural design has shifted from 2D to 3D, and to BIM, which includes a data management system. Within this background, however, there is currently no adequate BIM-based LCC analysis software and the requirements of cost estimation for repair and replacement cost for a building is not completely adequate in BIM tools such as Revit and Archicad. Therefore, this study suggests a process of cost estimation for repair and replacement (R&R) cost based on IFC data. First, we analyzed existing R&R criteria and defined BIM-based requirements when calculating R&R costs. These requirements were extracted from relevant IFC data. Subsequently, this was saved to a database and a BIM-based database was built for R&R cost estimation. Finally, this database was connected with external databases such as R&R Criteria DB and Cost Information DB to calculate R&R costs. This process is expected to improve upon the traditional process of cost estimation of R&R cost by applying a BIM model. The proposed process can contribute to a further standardizing of BIM-based LCC analysis thru application to initial construction costs, energy costs, and other maintenance costs.

• Journal of the Korea Institute of Building Construction
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• v.10 no.1
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• pp.193-198
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• 2010

This study aimed at presenting the improvement plan for estimation of the repair and replacement cycle to analyze these current problems by considering the repair and replacement cycle theoretically and examining estimation status of home and abroad, and then drawing implication and problem based on brainstorming and expert opinion. The findings of a study is as follows. First, the problem is, for the domestic, that there is no clear standard of division to the cycle of repair and replacement and the repair and replacement cycle considering capability to deal with the change by construction method, development of the function of material and the number of years of progress is not being applied. That is, an estimation of economical repair and replacement cycle which considers the case that a large scale repair with the level of remodeling is done between 25 years and 35 years is necessary. For estimating the repair and replacement cycle, foreign country is providing this according to the use or the level of function of a building, but it is not the case for the domestic. A characteristic of each building should be reflected and the standard of estimation of the repair and replacement cycle to new construction material or method should be prepared to improve this. In addition, the method of classification of the subject item for the repair and replacement is necessary to be reorganized to be able to apply the standard of initial construction item of a building. Also, it is considered that a service standard which can reset the repair and replacement cycle based on status of a building with escape from the existing definite setup of the repair and replacement cycle through the management of background data of the repair and replacement is going to be necessary.

• The Journal of the Acoustical Society of Korea
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• v.19 no.8
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• pp.78-83
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• 2000

Passive sonar system is designed to classify the underwater targets by analyzing and comparing the various acoustic characteristics such as signal strength, bandwidth, number of tonals and relationship of tonals from the extracted tonals and frequency lines. First of all the precise detection and extraction of signal frequency lines is of particular importance for enhancing the reliability of target classification. But, the narrowband frequency lines which are the line formed in spectrogram by a tonal of constant frequency in each frame can be detected weakly or discontinuously because of the variation of signal strength and transmission loss in the sea. Also, it is very difficult to detect and extract precisely the signal frequency lines by the complexity of impulsive ambient noise and signal components. In this paper, the automatic detection and extraction method that can detect and extract the signal components of frequency tines precisely are proposed. The proposed method can be applied under the bad conditions with weak signal strength and high ambient noise. It is confirmed by the simulation using real underwater target data.

• Korean Journal of Construction Engineering and Management
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• v.18 no.3
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• pp.12-21
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• 2017

From 1960, the government decided to build apartment houses on a large scale in order to resolve the rising housing problems. However, the maintenance issues that have arisen from the deterioration of housing has not received adequate attention. The policy focuses only on the supply of housing. By passing new laws, the durable period during which buildings allowed reconstruction was increased, and long term maintenance plans were treated as important issues. The government was then obligated to establish certain long term maintenance plans and costs by legislating a Housing Act and requiring it be adjusted every three years. However, when planning long-term repair costs, doing so without considering the time value of money would become a problem. In addition, if differences between the planned repair costs and actual costs occur, it becomes necessary to adjust the long-term repair costs but, as of yet, the criteria to adjust such things does not exist. For these reasons, if there is lack of money to execute large-scale repair work, a building is unlikely to respond to deterioration of housing; on the other hand, an unnecessary reserve or pool of money can lead to conflict among residents. Therefore, this paper will propose estimation and adjustment models considering the time value of money for long term maintenance costs of apartment houses.

• Proceedings of the Korea Air Pollution Research Association Conference
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• 2001.11a
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• pp.273-274
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• 2001

세계 여러 나라에서는 구두를 닦거나 수선하는 직업에 종사하는 사람들이 있고 우리 나라 역시 그렇다. 그러나 우리 나라 구두기능 미화원들의 작업환경은 독특한 형태로서, 우리 나라는 1991년 8월부터 서울시내 도로변(人道)에 구두수선대라는 명칭으로 구두수선박스가 곳곳에 점유하고 있다. 본 연구는 도시지역 대기오염의 주 요인이 차량임을 고려하여 도로변 구두수선대 실내 및 실외의 PM3.5와 이산화질소(NO$_2$)를 측정하였고, PM3.5/NO$_2$ 농도비를 계산하였다. (중략)

• Journal of the Korea Institute of Information and Communication Engineering
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• v.17 no.3
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• pp.546-555
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• 2013

In this paper, we propose a novel method to enhance the harmonic components from the frequency lines of the passive sonar signals. For this, we first separate the stable frequency lines from unstable ones using mean and difference of spectral bins in the vernier analysis. Then we emphasize the harmonic components using autocorrelation-based postprocessing, and enhance them by reducing the background noise with the split-window two pass mean algorithm. Experimental results for real underwater acoustic data are presented with our discussions.

• Proceedings of the Korean Institute Of Construction Engineering and Management
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• autumn
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• pp.355-358
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• 2002

Since the 1960s, though there were brisk supply in apartment housing, there were no preparation in standard for to extend the life(durability) of apartment housing by maintaining the $social{\cdot}physical$ aspect of apartment housing, and in standard maintenance system. So problem such as facilities safety and residence environment has occurred. Like the condition written above, efficient usage of housing resource by the maintenance of apartment housings in a state of great urgency. In service aspect of apartment housing, establishment of accurate long term repair plan and estimate of repair appropriation fund can prevent housing's fast-deterioration. But to the performers of the maintenance, like house managers and the tenants at the subject building has little awareness of necessity in establishment of accurate long term repair plan and accumulation of repair appropriation fund. Unestablishment of long term repair plan arises problem such as approval of repair appropriation fund's unreasonable accumulation. Hence, for the utmost performance of apartment housing and to extend the economic life of a building, the method of establishment of long term repair plan and estimate of repair appropriation fund on reliable basis is to be proposed.

• Journal of the Korea Institute of Building Construction
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• v.10 no.2
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• pp.41-50
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• 2010

This study presented a model that can enable a reliability analysis for the repair and replacement cycle of a building by using background repair and replacement data and expert opinion as foundation data and applying Monte Carlo Simulation. The presented model offers the time of the repair and replacement of building elements for the period of a year, and supports the prediction of repair and replacement and expenses demand in advance while planning the maintenance of a building. In addition, the model will significantly reduce the risks to the building owner with regard to maintenance decisions. In addition, when a person in charge of the maintenance of large-scale building assets is having difficulties making decisions regarding the repair and replacement of existing building elements due to a lack of background data to support a long-term policy on the repair and replacement requirements, an engineering solution that can ensure the adequacy of this is provided. In summary, it can be largely divided into three study results. First, a method of estimating the repair and replacement cycle that can deal with the development of a construction system was developed. Second, a probabilistic methodology that can quantify the risk of the repair and replacement cycle was proposed. Third, the proposed model can be used as a means of supporting designer and constructor in making decisions for the life cycle plan of a building during a construction project.

• Korean Journal of Construction Engineering and Management
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• v.16 no.1
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• pp.52-63
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• 2015

Business facilities among domestic architectures have rapidly been constructed along with domestic economic development. It is an important facility taking the second largest proportion next to apartment buildings among current 31 building types of fire department classification of 2012 year for urban architectures. The expected service life of business facilities is 15 years, but 70% of those in urban areas have surpassed the 15 year service life as of the present 2014. Thus, the demand for urgent rehabilitation of such facilities is constantly increasing due to the aging and performance deterioration of the facilities'main finishing materials. Especially, the business facilities are being used for the lease of company office or private office, and such problems as aging and performance deterioration of the facilities could cause less competitive edge for leasing and real estate value depreciation for the O&M (Operation & Management) agent and the owner, respectively. Therefore, an effective planned rehabilitation as a preventive measure according to the standardized repair rate by the number of years after the construction is in need in order to prevent the aging and performance deterioration of the facilities(La et al. 2001). Nonetheless, domestic repair/rehabilitation standards based on the repair rate are mainly limited to apartment buildings and pubic institutions, resulting in impractical application of such standards to business facilities. It has been investigated and analyzed that annual repair rate data for each finishing material are required for examination of the applicability of the repair rate standard for the purpose of establishment of a repair plan. Hence, this study aimed at developing a repair rate computation model for finishing materials of the facilities and verifying the appropriateness of the annual repair rate for each finishing material through a case study after collecting and analyzing the repair history data of six business facilities. The results of this study are expected to contribute to the planning and implementation of more efficient repair/rehabilitation budget by preventing the waste of unpredicted repair cost and opportunity cost for the sake of the business facilities' owners and O&M agents.

• Journal of the Korea Institute of Building Construction
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• v.17 no.5
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• pp.473-481
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• 2017

With the barracks modernization project, the Ministry of National Defense has been operating 60 projects of the 75 that have been announced. It was difficult to investigate and analyze the data in the past because data could not be obtained while it was much easier to do that since data can be obtained from private companies. With the aim of increasing the usability of the facilities, the objective of this study is to present a reasonable alternative for repair and maintenance costs by investigating and analyzing the budget and the actual expenses of repair and maintenance of military facilities for the past 3 to 5 years, and then identifying the problems with these. To accomplish this, a theoretical review of previous studies and legal grounds related to repair and maintenance costs was performed, and data on the estimates and the actual expenses data used in BTL projects carried out by private companies were analyzed. First, one of the problems was that there are some items omitted, including consumables, and these items should be included in order to secure their budget. Second, in terms of the items for divided payments, two improvements had been presented: a short-term payment plan for the operation period of 3 to 5 years and a long-term payment plan for an additional and complemented period other than the operation period. The repair and maintenance costs should be further studied at the point of time in a future when the actual data on the costs and operation period of military facilities can be secured. This study is expected to serve as empirical data that will form the basis for a reasonable calculation of the construction cost for military facilities.