• International conference on construction engineering and project management
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• 2009.05a
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• pp.1170-1175
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• 2009

When managers estimate exact construction cost at early stage and design phase, they can reduce construction cost in a more efficient way than to predict at construction stage. But, the current of public construction cost estimation and management is concentrated almost after detailed design phase. Therefore, construction cost management in design development phase to generally use approximate estimating is not correct. Also, the existing construction cost used the method that estimated by gross floor area-based cost estimates at design development phase. So, it is difficult to show the specific amount of materials and basis about the estimated cost of the construction. This study derived problems and limits of construction management at design development phase in case of public office building project through review of literature and current survey, and suggested estimating process model process of structural construction cost go improve these matters.

• International conference on construction engineering and project management
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• 2022.06a
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• pp.253-260
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• 2022

Existing web-based cost databases have proved invaluable for construction cost estimating. These databases have been utilized to compute approximate cost estimates using assembly rates, unit rates, and etc. These web-based databases can be used independently with traditional cost estimation methods (manual methods) or used to support BIM-based cost estimating platforms. However, these databases are rigid, costly, and require a lot of manual inputs to reflect recent trends in prices or prices relative to a construction project's location. To address this gap, this study integrated deep learning techniques with web-based price analysis to develop a database that incorporates a project's location cost estimating standards and current cost trends in generating a cost estimate. The proposed method was tested in a case study project in Lagos, Nigeria. A cost estimate was successfully generated. Comparison of the experimental results with results using current industry standards showed that the proposed method achieved a 98.16% accuracy. The results showed that the proposed method was successful in generating approximate cost estimates irrespective of project's location.

• International conference on construction engineering and project management
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• 2015.10a
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• pp.604-605
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• 2015

To secure quality of dam construction needs appropriate construction duration. Tight construction schedule may have negative influence on infrastructure quality, work safety and maintenance cost. It is necessary to reflect proper construction duration in the planning phase. There have been standards for estimating construction duration of building and industrial complex development but dam construction have not. In order to estimate construction duration of CFRD, feasible study reports and design reports were analyzed to acquire available information. After that, considering on construction duration methods such as comparison with similar cases, approximate estimating formula, approximate quantity assumption were adapted to Critical Path items. Hence, this study present framework for construction duration estimating of CFRD in the planning phase. This framework can be applied other types of dam along the same line.

• Korean Journal of Cognitive Science
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• v.24 no.3
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• pp.271-300
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• 2013

Human and animals are born with an intuitive ability to determine approximate numerosity. This ability is termed approximate number sense (hereafter, number sense). Evolutionarily, number sense is thought to be an essential ability for hunting, gathering and survival. According to previous research, children with mathematical learning disability have impaired number sense. On the other hand, individuals with more accurate number sense have higher mathematical achievement. These results support the hypothesis that number sense provides a basis for the development of mathematical cognition. Recently, researchers have been examining whether number sense training can lead to enhancement in mathematical achievement and changes in brain activity in relation to mathematical problem solving. Numerosity which basically represents discontinuous quantity is expected to be closely related to continuous quantity such as representations of space and time. A theory of magnitude (ATOM) states that processing of number, space and time is based on a common magnitude system in the posterior parietal cortex, especially the intraparietal sulcus. The present paper introduces current literature and future directions for the study of the common magnitude system.

• The Journal of the Korea institute of electronic communication sciences
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• v.14 no.4
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• pp.679-684
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• 2019

We propose a method to measure the number of specific species of class using CAFFE model and a method to measure length and width of object using stereo vision. To obtain the width of an object, the location coordinates of objects appearing on the left and right sensor is compared and the distance from the sensor to the object is obtained. Then the length of the object in the image by using the distance and the approximate value of the actual length of the object is calculated.

• Proceedings of the Korean Operations and Management Science Society Conference
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• 1998.10a
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• pp.392-395
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• 1998

This paper suggests the“infinite-retailer model”to approximate expected backorders per cycle of the One-warehouse N-retailer distribution system where the warehouse holds back some of the replenishment quantity to satisfy retailer backorders at the end of the cycle through direct shipping to customers. The main objective is to show the functional relationship between the warehouse inventory and the expected backorders per cycle. We illustrate the relationship using a uniform demand case.

• Management Science and Financial Engineering
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• v.13 no.1
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• pp.35-53
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• 2007

We consider a(worst-case) robust optimization version of the Economic Order Quantity(EOQ) model. Order setup costs and inventory carrying costs are assumed to have uncertainty in their values, and the uncertainty description of the two parameters is supposed to be given by an ellipsoidal representation. A genetic algorithm combined with Monte Carlo simulation is proposed to approximate the ellipsoidal representation. The objective function of the model under ellipsoidal uncertainty description is derived, and the resulting problem is solved by another genetic algorithm. Computational test results are presented to show the performance of the proposed method.

• Magazine of the Korean Society of Agricultural Engineers
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• v.16 no.4
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• pp.3585-3593
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• 1974

This thesis a result of theoretical and experimental studies on the shape of seepage line and seepage quantities in various inclined core walls. The value of this determination was examined and compared with the values of calculation acquaired to be based on Fukutas, Jin's and author's approximate equation of the theory. Thus the writer of this paper confirms that the seepage quantity can be decreased by changing the types of the inclined core wall and it's change of the slope.

• Journal of the Korea Institute of Building Construction
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• v.13 no.5
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• pp.506-512
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• 2013

Since the amendment of the law on the private sector investment in social infrastructure in January of 2005, the government has been actively promoting Build-Transfer-Lease (BTL) projects. Notably, most new educational facilities have been built as BTL projects. For these facilities, the unit cost per unit area has been applied to predict construction costs. However, since construction costs are mostly managed after the detailed design phase, the costs can be estimated incorrectly. For this reason, cost management is needed in the planning phase, with a sound approximate estimate to prevent the wasteful use of funds. To address this shortcoming, this study aims to develop a quantity prediction model for education facilities using regression analysis in the planning phase. The developed model is focused on the required quantities of reinforced concrete and bricks. In order to achieve the objective, the data of 44 educational facility projects collected from Gyeonggi-do was used in the regression model. This study can be utilized by major stakeholders to accurately predict construction costs by estimating the appropriate quantities of reinforced concrete and bricks in the planning design phase.

• Journal of the Korea Institute of Building Construction
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• v.20 no.2
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• pp.147-153
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• 2020

It is important to estimate the optimal construction cost at the early stage of the project. In this regard, conceptual cost estimate is an important factor for estimate optimal construction cost. However, domestic conceptual cost estimate are only used as cost per unit area according to the building type, and it's accuracy is not high. Hence, the purpose of this study is to calculate the approximate quantity and cost for reinforcing bars, concrete, and formwork by presenting a regression formula based on the total floor area of the common work items in the frame work. In order to verify the accuracy and validity of the regression formula presented in this study, a comparative analysis was performed by applying the regression formula and the traditional approximate quantity take-off method to real cases. As a result, the estimated error rate of the traditional method was -102~+55%, and exceeded the estimated conceptual cost estimate accuracy range of -50~+100% suggested by AACE(American Association of Cost Engineering). On the other hand, the error rate of the regression formula method presented in this study was -6.4~+11.62%. This can be used not only for conceptual cost estimate range of accuracy, but also for detailed estimates. However, it is necessary to analyze the factors that affect the unit price as well as quantity in order to calculate the appropriate cost.