• Korean Journal of Construction Engineering and Management
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• v.3 no.4 s.12
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• pp.114-122
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• 2002

Earned Value Management System(EVMS) is a management technique that is emerging as a valuable tool in the management of all projects, including and in particular construction projects. It is based on C/SCSC that has been released by the U.S. Department of Defense (DOD) in 1967. In a project that employs the earned value management concept, the project's measurable performance plans will be formed with the creation of CAPs. The formation of CAPs is a planning step necessary to form an earned value baseline. In this paper, a method is proposed to form CAPs using Material Requirement Planning(MRP) that is also known as a useful planning tool in the manufacturing industry. An application to a real project has been carried through workpackaging model.

• Proceedings of the KIEE Conference
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• 2009.07a
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• pp.521_523
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• 2009

최근 고유가에 따른 발전비용 증가와 교토의정서 발휘로 인한 $CO_2$ 저감의무 등 환경보전이라는 사회적 요구와 맞물려 새로운 신재생에너지 분야에 관심이 고조되고 있는 실정이다. 이러한 신재생에너지로 대표되는 풍력, 태양광, 연료전지 등을 이용하는 발전방식은 저용량의 발전으로 대규모 집중형 전원이 아니 전력 수요지 근방에서 설치되는 비교적 작은 규모의 분산형전원(DG;Distribution Generator)으로 배전선로에 직접 연계됨에 따라 배전계통에도 큰 변화가 일고 있다. 분산전원(DG)이 배전계통에 연계됨에 따라 전압변동에 따른 전압조정, 고조파 계통유입에 따른 전기품질, 계통고장시의 분산전원의 단독운전 방지, 고장전류의 분산에 따른 선로의 보호협조 등 다양한 새로운 문제점이 대두되고 있고 이를 해결하기 위해 연구개발 및 신기자재개발 등이 활발히 진행되고 있다. 현재 배전자동화시스템에 적용되고 있는 고장검출 알고리즘은 단방향으로 전기를 공급하던 전통적인 배전방식에서 단순 과전류요소에 의해 고장검출하는 알고리즘을 적용하고 있기 때문에 분산전원이 연계된 양방향 전기공급 배전계통에서는 정확하게 고장구간을 검출하기 어렵다. 이로 인해 고장판단 문제점과 보호기기의 오동작 등으로 정확하게 고장구간을 판단하지 못하여 광역정전이 발생되고 고장복구가 장시간 소요되고 있는 실정이다. 본 논문에서는 이를 해소하기 위해 양방향 전기공급 배전계통에서 고장이 발생시 고장점으로 유입되는 고장전류의 파형형태를 분석하여 고장 구간을 판단하는 알고리즘을 소개하고자 한다. 또한 다기능 mFRTU(mFRTUmulti-function Feeder Remote Terminal Unit) 의 고장 구간 판단 알고리즘의 신뢰성을 검증하기 위해 실선로에서 실증시험을 시행하였으며, 그 결과를 분석하여 타당성을 제시하고자 한다.

• Proceedings of the Korea Concrete Institute Conference
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• 2008.11a
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• pp.557-560
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• 2008

This was done by analyzing the sandwich panels that are now widely used in construction work. Sandwich panels are used for diverse purposes in construction work worldwide. In Korea, polystyrene panels that have organic materials as their core material are used. These panels are thus very vulnerable to fire, with risks of core melting, sheet deformation, and hazardous gases. Accordingly, sandwich panels' fire-resistant or non-flammable properties must be secured. To solve these problems, the optimal mixing proportion of lightweight foamed concrete for the sandwich panel core was determined. A new method of doing this was introduced that is completely different from the existing method, wherein a foaming agent is added to realize lightweight concrete. For lightweight concrete, the foaming mechanisms via diverse chemical reactions were identified, H$_2$O$_2$ was added for heating in the reaction, and the concrete foaming was maximized. Through diverse experiments to determine the optimal mixing proportion of lightweight foamed concrete and to examine the filling characteristic of lightweight foamed concrete for sandwich panel cores using waste materials, the physical and mechanical properties of lightweight foamed concrete were examined.

• Proceedings of the Korean Institute Of Construction Engineering and Management
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• 2006.11a
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• pp.444-447
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• 2006

Construction managers need to pay a close attention to the resource utilization in order to deliver the construction project successfully. Construction scheduling is crucial for resource control in that it provides information when and how much to bring down work force to sites. In scheduling, activity duration is projected based on the productivity of historical data or the intuition of scheduler. This paper studies the opportunity of applying cost-based productivity for estimating activity duration. For cost-based productivity, the cost of resource is used as an input and the work quantities as an output. Out of historical data, regression model has been developed to understand the validity of applying cost-based productivity in projecting activity duration. The result of study will work as a prerequisite for implementing the environment of database-based construction scheduling.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.41 no.1
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• pp.115-122
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• 1996

One of the most laborious work in rice farming is transplanting of rice seedling which has been required preparation of nursery bed and care of seedling during one month period. In this research, direct seeding in dry paddy(DS) and direct seeding in wet paddy(WS) were practiced to compare with traditional transplanting(TP) in Suwon. Growth stages in direct seeding were delayed as its planting time was about 21 days later than those of TP. Heading stage of direct seeding at Suwon was delayed about 9 days as compared to transplanting culture. Rice yield was not different between the seeding practises. Working-hour saving was about 17％(DS) and 28％(WS). Production cost of direct seeding was decreased 20％(DS) and 32％(WS), respectively. Amount of rice production per a unit working-hour in direct seeding could increase 14％(DS) and 39％(WS) compared to that of TP, respectively. Therefore, direct seeding could save significantly working hour and production cost without reducing rice yield. WS was more effective than DS in saving labor and production cost. Direct seeding was not efficient method in input of farming energy and agricultural chemicals.

• Proceedings of the Korean Institute Of Construction Engineering and Management
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• autumn
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• pp.410-415
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• 2001

Earned Value Management System(EVMS) has been considered as a useful tool of managing construction projects lately and its instruction into a private industry is now under consideration by the Korean government. It is on the basis of C/SCSC that had been released by the U.S. Department of Defense(DOD) since 1967. Its research has been in the active progress in order to utilize the earned value concept as a project management tool for construction project ordered by both government and private sector. Material Requirement Planning(MRP) is also known as a tool of planning and scheduling resources for assembly product as a part of inventory control models in the manufacturing industry. The purpose of this study is the effective employment of Earned Value Management to manage the construction projects by utilizing Material Requirement Planning(MRP), based on project management software and Workpackaging model.

• Journal of Digital Convergence
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• v.11 no.3
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• pp.181-187
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• 2013

Moreover a new logistics concept is needed through the sharing information between suppliers and consumers, which maximizes the level of customers service and its flexibility by changing functional-oriented to process-oriented. In other words, Supply Chain Management(SCM) is now considered as a key aspect of business, which controls the flows of information, funds, and goods in the supply chain. Rationalization of transport-delivery system will be one of the most important issues on logistics management to the domestic companies. The companies need the effective delivery system. Especially in the case of delivery system from distribution centers to customers or vendors, it might take a long time to control the delivery system manually because it would be hard to apply the automatic vehicle routing algorithm effectively considering all the practical constraints. Thus this study develops a heuristic algorithm of automatic vehicle delivery support system in terms of grouping by short ranges of vehicle movement utilizing postal coordinates, which satisfies a variety of realistic constraints and reduces controlling time of manual operations.

• Fire Science and Engineering
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• v.29 no.1
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• pp.73-79
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• 2015

There are three kinds of design method of the fire sprinkler systems. Grid type is connected all branch as a trapezoid. Loop type is connected cross-mains like circle. The last one is a tree type most commonly used. Grid type needs computer program to calculate the friction loss and flow rate apart from very simple form. In loop type, manual calculation is possible. Design engineer can draw up and calculate the demands without computer program. Because water supplies two direction in loop type, friction loss is smaller than tree type. Water distribution in operation area is uniform because of the small differences of sprinklers discharge pressure. Loop type is superior to tree type in respect of total pressure and flow rate. Using the small diameter pipe, the labor and construction cost will be decreased in the end. Loop type sprinkler design is rarely laid out because design engineers don't know the method. This paper is intended to inform that the loop type is better than the tree type in performance and economic point of view. And also this paper intend to use the loop type easily and widely.

• The Journal of the Convergence on Culture Technology
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• v.9 no.1
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• pp.531-537
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• 2023

Interior construction is required to estimate the quantity of material and the cost expected from 2D drawing in design phase and look for the reasonable method of work. Therefore, exact estimation for quantity and budgeting are very important processes, as a measure of judging the profitability of interior construction. These processes are mostly based on 2D drawing, so time and experienced staff are required. Error and omission can occur because the experienced staff also calculates the area using 2D based drawing. Interior market is currently based on 3D modeling from planning to final design. Accordingly, estimating quantity based on 3D modeling is emerging as a way of reducing error and omission. This paper will present the methodology on calculating area, the basic element of estimating quantity based on 3D Modeling in interior field.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.30 no.3A
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• pp.277-286
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• 2010

Derrick or caterpillar crane is generally used for the long-span/cable-stayed bridge construction by pre-cast segment lifting from over-land or water transportation. The heavy weight of them, however, could make defects on unstable under-construction structure and, furthermore a method of conventional segment transportation is also able to occur additional time and cost. In this study, in order to improve conventional construction method, the newly developed derrick crane is mainly considered. It could be not only eccentrically loadable on constructing girder but having rotatable boom for segment transportation from back-side. A series of construction stage using developed derrick crane is defined and also its numerical analysis is conducted. To reflect load characteristics of developed derrick crane on construction stage analysis, on/out of service load is separately calculated by considering vertical/lateral rotation range of boom and it is loaded on 4 fixed positions of crane. The derrick crane on this study could be time and cost saving solution for cable-stayed bridge construction and also make contributions to construction load reduction in its process.