• International conference on construction engineering and project management
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• 2009.05a
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• pp.409-416
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• 2009

This paper presents a tool called Quality-Cost optimization system (QCOS), which integrates Multi-Objective Genetic Algorithm (MOGA) and Quality Function Deployment (QFD), for tradeoff between quality and cost of the unitized metal curtain-wall unit. A construction owner as the external customer pursues to maximize the quality of the curtain-wall unit. However, the contractor as the internal customer pursues to minimize the cost involved in designing, manufacturing and installing the curtain-wall unit. It is crucial for project manager to find the tradeoff point which satisfies the conflicting interests pursued by the both parties. The system would be beneficial to establish a quality plan satisfying the both parties. Survey questionnaires were administered to the construction owner who has an experience of curtain-wall project, the architects who are the independent assessor, and the contractors who were involved in curtain-wall design and installation. The Customer Requirements (CRs) and their importance weights, the relationship between CRs and Technical Attributes (TAs) consisting of a curtain-wall unit, and the cost ratios of each components consisting curtain-wall unit are obtained from the three groups mentioned previously. The data obtained from the surveys were used as the QFD input to compute the Owner Satisfaction (OS) and Contractor Satisfaction (CS). MOGA is applied to optimize resource allocation under limited budget when multi-objectives, OS and CS, are pursued at the same time. The deterministic multi-objective optimization method using MOGA and QFD is extended to stochastic model to better deal with the uncertainties of QFD input and the variability of QFD output. A case study demonstrates the system and verifies the system conformance.

• Korean Journal of Construction Engineering and Management
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• v.10 no.2
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• pp.111-120
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• 2009

The conceptual cost estimation used the construction project needs for confirm budget not only at the planning phase but also at the preliminary design phase of the construction project. Present, the conceptual cost estimation model have problems the rate of error is very large because the linear simple model calculate by use the cost of the unit meter or the unit square. This study development the model used grouping and the key quantity method, the mixed unit cost for solve problem of the very large rate of error. The result of this study reduced difference of between the real design construction cost therefor it expect that contribute to the client or the service company estimate budget of RC rahmen bridge.

• Journal of the Society of Naval Architects of Korea
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• v.28 no.1
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• pp.197-205
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• 1991

A methodology of constructions a mathematical cost model for an activity constituting ship hull assembly process is proposed. The relationship between number of workers and processing time required for an activity can be formulated using an work study method, then manhours and shop floor area-hours required are calculated accordingly. The costs for unit manhour and unit shop floor area-hour respectively are calculated by distributing the overall annual cost of the company to the overall production resources consummed during the year. A general procedure of implementing the methodology has been demonstrated through a test on an exampled activity drawn from a real process.

• Journal of KIBIM
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• v.3 no.1
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• pp.11-20
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• 2013

Mix-used development in urban renewal project is done to effectively utilize the limited downtown. Generally unlike a single project, It features placing a large number of different facilities(residential, commercial, business, cultural, etc.) which is each other organically linked. The purpose of this study is to suggest the method of modeling guide for 3D preliminary cost estimation considering visual and intuitive judgement of space in mix-used development Urban Renewal project. In this research, introducing SME(Standard Module and Element) breakdown structure, FID(Finish Identity) for estimating building space unit-based quantity take off was implemented. It could narrow the discrepancy of opinion between the stakeholders with more accurate cost-estimates, comparing to the traditional methods.

• Journal of Applied Reliability
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• v.11 no.4
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• pp.409-417
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• 2011

In this paper, we consider a replacement model following the expiration of warranty. In other words, this paper proposes the optimal replacement policy for a repairable system following the expiration of payable renewing replacement-non-renewing minimal repair warranty. The expected cost rate per unit time from the user's perspective is used to determine the optimality of the replacement policy. Thus, we derive the expressions for the expected cycle length and the expected total cost to obtain the expected cost rate per unit time. Finally, the numerical examples are presented for illustrative purpose.

• Journal of Integrative Natural Science
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• v.14 no.4
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• pp.197-204
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• 2021

Under the two-phase warranty, the warranty period is divided into two intervals, one of which is for renewing replacement warranty, and the other is for minimal repair warranty. Jung^[13] discusses the two types of extended two-phase warranty models. In this paper, we suggest the replacement model after the extended two-phase warranty that has been proposed by Jung^[13]. To determine the optimal replacement policy, we adopt the expected cost rate per unit time. So, the expressions for the total expected cost, the expected length of the cycle and the expected cost rate per unit time from the user's point of view are derived. Also, we discuss the optimal replacement policy and the uniqueness of the solution for the optimization. Furthermore, the numerical examples are provided to illustrate the proposed the replacement model.

• Korean Journal of Construction Engineering and Management
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• v.7 no.5
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• pp.159-166
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• 2006

It was found that Korean Standard of Estimate which has been used as the only basis of cost estimate of public construction projects had some side effects such as jerry-build construction and over-estimation because it failed to reflect the current price and the state-of-the-art construction methods in a changing construction environment. Therefore, the government decided to gradually introduce historical construction cost into cost estimate of public construction projects from 2004. This paper presents analytic criteria and a process model for deducing more current and reasonable historical construction cost for contract items from not only previous contract prices but also all of the other bid prices that were not contracted. The procedure of estimating actual unit cost proposed in this paper focuses on the removal of abnormal values including strategically too low or high prices and the time correction. In addition, basic research is conducted for the correction of actual unit cost through the analysis of fluctuation of bid price depending on bidding types and rates of successful bid. It is anticipated that the effective use of the proposed process model for estimating actual unit cost would make the cost estimation more current and reasonable.

• 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.

• Proceedings of the Korea Society for Energy Engineering kosee Conference
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• 1998.05a
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• pp.271-277
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• 1998

1. Why Wind Power\ulcorner Advantages of Wind Energy : free cost, non-pollutant, free waste large unit is possible Disadvantages : intermittent of energy density limited sites Unit Capacity of various Power Plant Solar PP : 10 - 500㎾ Wind PP : 200 - 2000 ㎾ Nuclear PP 700 - 1000 MW Installation Cost of Power Plants Nuclear PP : $ 2,500/㎾ Solar PP : $ 6,000/㎾ Wind PP : $ 1.000 /kw.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.67 no.11
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• pp.1523-1529
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• 2018

Electric vehicles that are currently in operation are being produced domestically. Therefore, there is no great difficulty in receiving or repairing the failed parts or in the overall repair. On the other hand, most of the electric locomotives are manufactured by introducing the parts and technology of foreign vehicle manufacturers. In this paper, conducted a study about life cycle cost analysis of developed auxiliary power unit in 8200 series electric locomotive and suggested cost down method. This confirms the economic benefits of the developed products of the auxiliary power supply compared to the existing products. In addition, a sensitivity analysis of MTBF was conducted to suggest a life cycle cost down method.