• Proceedings of the Korean Institute Of Construction Engineering and Management
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• 2007.11a
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• pp.383-386
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• 2007

Recently, The percentile of the apartment housing within the apartment construction of domestic is increasing daily. Especially the construction duration in apartment construction is an very important factor which affects project cost. Therefore the construction companies the effort to shorten construction duration. The influence factors of the construction duration are analyzed to shorten construction duration through this tendency. The shown factors are needed to assessment method efficiently. This study is to suggest a method for the assessment of influence factors about the shortening of the construction time in apartment housing based on the FMEA(Failure Mode and Effect Analysis) method.

• International Journal of Railway
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• v.9 no.1
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• pp.21-26
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• 2016

When excavation under existing structure is planned for a new construction project, the underpinning method is one of the most applicable construction methods. This study introduces a new modified underpinning method which is applied to construct a new subway line in Seoul Metropolitan. The new subway line was designed to pass underneath the existing subway line. Existing subway line carries about 2 million passengers daily, which is 33% of total passengers using subway in Seoul, and is the only circulation line in Seoul. Subway trains are passing 540 times through this section in a day. By applying a new underpinning method, the subway box structure of line is exposed 54m in the air supported by bearing piles. The proposed method was carefully monitored using heavy instrumentation system during construction. This study proposed and verified the application of the modified underpinning method, which can reduce construction period by 1.5 times and the construction cost by 1.2 times comparing with conventional method. The importance of considering construction sequence is investigated and verified by analyzed data non-considering construction sequence. The unexpected heaving which can bring up a dangerous situation for train running stability were measured, so this study shows that the upward movement has to be analyzed in designing process. As the use of underground space increases, the proposed method can be a good example of underground development.

• Journal of the Korea Institute of Building Construction
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• v.11 no.5
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• pp.468-481
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• 2011

This research presents a strategy and information system to manage the logistics of delivery ready mixed concrete (RMC) under the integrated environment of PMIS+RFID. PMIS is system tool and technique used in construction sectors to delivery information. Information that can be extracted electronically in real time is more valuable than data gathered and maintained manually. RFID technology can help to improve data accuracy through supply chains and by identifying products and objects at specific points through automatic identification. The objectives of these two implementations can be able to improve the efficiency of logistics management for RMC truck process, and to verify the technical and practical feasibility of PMIS+RFID application in construction industry. This may be realistic given the dynamics of daily activities on construction sites. This research is focused on examples on real world case study, applications and research theme related and connected to PMIS+RFID technology. It demonstrated that PMIS+RFID technology has been automatically implemented and has shown process information about the RMC truck and the overall status information about it, both quickly and accurately. As a result, the construction site where needs 300 $m^3$ pouring (50 RMC trucks) per day can be reduced total 250 minutes. Moreover, this time saving is related to the labour cost saving. From the case studies, RFID+PMIS system was proven in terms of effectiveness rather than current method.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.25 no.10
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• pp.28-37
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• 2011

Though Korea has introduced CBP(Cost Based pool) power trading system since 2001, long-term Generation system planning has been executed by government for Cost minimization every 2 years. Until currently the model which is used for Generation system planning and best-mix only considers cost minimization and total yearly or quarterly electricity demand every year. In a view point of one day power supply operation, technical characteristics, like the ramp up/down rate of total generation system, minimum up/down time and GFRQ(Governor Free Response Quantity), are very important. this paper analyzes Optimal Fuel-Mix for 2022 Korea generation system satisfying these constraints of each fuel type and considering pump storage plants, construction cost and $CO_2$ emission charge Using MILP(Mixed Integer Linear Programming) method. Also the sensitivity analysis which follows in future power industry environmental change accomplished.

• Korean Journal of Construction Engineering and Management
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• v.7 no.3 s.31
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• pp.45-55
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• 2006

This study aims need set of mind to construction manager built a theory logic conceive decision making system and principles designed to create the administrative procedures that a company needs to integrate management and environmental concerns into its daily business practices. Integrate considerations of risk reduction and wise resource management into daily business decision making environmental that includes performance and cost. Seek to make better Dynamic time solutions that promote competitiveness set of management mind provide business with tools and methodologies management participation, psychology, philosophy effects of resource flows. A last of understand use of the decision making element principal as a guideline for evaluating and ranking approaches. The result of this study are summarized as follows; (1) setting for approach decision making of manager police, (2) dynamic of time and management mind (3) a primary factor out environment to decision making (4) methodologies of set up system for management mind (5) expectation effect of management mind.

• Journal of KIBIM
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• v.9 no.2
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• pp.1-10
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• 2019

In this research, schedule optimization is defined as balancing the number of workers while keeping the demand and needs of the project resources, creating the perfect schedule for each activity. Therefore, when one optimizes a schedule, multiple potentials of schedule changes are assessed to get an instant view of changes that avoid any over and under staffing while maximizing productivity levels for the available labor cost. Optimizing the number of workers in the scheduling process is not a simple task since it usually involves many different factors to be considered such as the development of quantity take-offs, cost estimating, scheduling, direct/indirect costs, and borrowing costs in cash flow while each factor affecting the others simultaneously. That is why the optimization process usually requires complex computational simulations/modeling. This research attempts to find an optimal selection of daily maximum workers in a project while considering the impacts of other factors at the same time through OPEN BIM based multiple computer simulations in resource leveling. This paper integrates several different processes such as quantity take-offs, cost estimating, and scheduling processes through computer aided simulations and prediction in generating/comparing different outcomes of each process. To achieve interoperability among different simulation processes, this research utilized data exchanges supported by building SMART-IFC effort in automating the data extraction and retrieval. Numerous computer simulations were run, which included necessary aspects of construction scheduling, to produce sufficient alternatives for a given project.

• Proceedings of the Korea Concrete Institute Conference
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• 2003.11a
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• pp.261-264
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• 2003

Cold weather can lead to many problems in mixing, placing, setting time, and curing of concrete that can have harmful effects on its properties and service life. Korean Concrete Institute (KCI) defines cold weather as a period when the average daily air temperature is less $4^{\circ}C$ and recommends to cast concrete with special care such as shielding, heating and so on. The use of high early strength cements may improve the rate of hardening characteristics of concrete in cold weather by making it possible to achieve faster setting time and evolving more hydration heat than ordinary Portland cement. Higher early strength can be achieved using Type III cement especially during the first 7 days. The strength increase property of Type III cement at low temperature was studied. As a conclusion the heat or heat insulation curing period can be reduced to 50~75%. So, it can be used for cold weather concreting to reduce construction cost and extend the construction season.

• International Journal of Highway Engineering
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• v.19 no.2
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• pp.113-126
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• 2017

PURPOSES : This study proposes standards for rural access road pavement section and thickness design considering existing access road construction conditions; the study also proposes a complementary policy that can be used for design convenience. METHODS : Various literature review and case studies had been performed in terms of rural access road section and thickness design, both domestically and internationally, and this was followed by domestic rural access road field surveys. KPRP and KENLAYER were used to analyze the commonalities and predict the remaining life. Data on real cost is used to select an appropriate construction method through economic analysis. RESULTS : The economic efficiency of concrete pavement ($15{\times}15$) was the highest in terms of economic efficiency of performance life and traffic volume. In the case of asphalt pavement, it is considered that the most economical method is to implement micro-surfacing method four times as a preventive maintenance method (once every 10 years and 4.5 years for asphalt concrete pavement and MS construction method, respectively). Repairable asphalt pavement is advantageous for areas where heavy vehicles are expected to pass. In the case of other general areas, it is considered economical to place concrete ($15{\times}15$) pavement. However, as analytical results on its performance life are unavailable, it is to be considered for study in the future. CONCLUSIONS : This study proposed interim design guidelines based on various domestic and international design guidelines and case studies. However, in order to develop the final design criteria applicable to the field, it is necessary to (a) estimate the bearing capacity of the lower level of the pavement at various sites, (b) estimate the daily traffic volume, (c) implement advanced low-cost pavement technologies, and (d) propose maintenance standards and techniques for long-term performance.

• Korean Journal of Construction Engineering and Management
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• v.14 no.3
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• pp.134-145
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• 2013

Road construction projects are parcelled into sub-sections which are then tendered to individual contractors for construction. The type of work and equipments used are similar for each sub-section. However, such equipment are not shared on a regular basis among the contractors and only partially performed in an informal and ad hoc manner. Consequently, road construction equipment suffer from low utilization and increased leasing costs. Lean construction and Program Management approaches stress the importance of collaboration among individual participants in a way that increases the collective cost savings of the entire project. This research attempts to apply such theories with the notion that under utilization of expensive equipment can be improved by formalizing a way to enable the sharing of equipment in large, public sponsored, multi-sectioned road construction projects. A system was developed consisting of a set of criteria and processes that enables automatic allocation of equipment to multiple sites on daily basis, in a way that minimizes equipment costs and improves their individual utility. The system was then applied in allocating three different types of equipment to an actual road construction project with four sub-sections for three months. A new metric, nDPR showed that utilization improved for all equipment and also equipment related costs were decreased by 4.45%. Results also showed that increased shared opportunities of equipment correspond to an increase in utilization and cost savings.

• Journal of the Korea institute for structural maintenance and inspection
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• v.15 no.1
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• pp.148-158
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• 2011

As critical infrastructure, bridges play an indispensable role in facilitating the distribution of goods. When bridges reach their end of useful life or get damaged by natural disasters such as earthquakes or storms, they have to be removed and reconstructed. When bridges in service need to be reconstructed, user costs occur from vehicle detours and traffic congestions, and social costs occur from noise and dust during construction periods. However, these user and social costs are not considered during reconstruction and the evaluation methods of those costs are vague. Thus, there is lack of appropriate bridge types that consider these costs. Therefore, this paper identifies the social overhead costs that occur during bridge reconstruction, which is also called, users' socioeconomic values. Next, it proposes a method to evaluate user costs during bridge reconstruction, and appraises the method. User costs are evaluated based on traffic information, social and material volumes including the bridge's daily traffic volume, peak hours, detour distance and time. In addition, time delay costs due to traffic operational costs and bridge reconstruction are also taken into consideration.