• Journal of the Korean Data and Information Science Society
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• v.25 no.4
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• pp.941-949
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• 2014

Unit level logistic regression model with mixed effects has been used for estimating small area proportions, which treats the spatial effects as random effects and assumes linearity between the logistic link and the covariates. However, when the functional form of the relationship between the logistic link and the covariates is not linear, it may lead to biased estimators of the small area proportions. In this paper, we relax the linearity assumption and propose two types of kernel-based logistic regression models for estimating small area proportions. We also demonstrate the efficiency of our propose models using simulated data and real data.

• Journal of the Korean housing association
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• v.6 no.2
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• pp.33-42
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• 1995

At the moment the housing demand needs estimated at the level of provinces and big cities. But at the level of small cities and smaller administrative unit like Goon, it is not, for lack of appropriate estimating method. Therefore it is very much required to develope appropriate estimating method at such levels. This study is an attempt to apply to some local areas the estimating method developed by Professor Miyqke of Japan as is suggested in his article. "How to Estimate the Housing Demand in Relation with the Different of Poulation Structure." The result shows that the applied local areas showed repective characteristics distinguished from one another in the pattern of housing demand, to prove the approprateness of the method when applied to the areas at the level of small cities and Goons.

• 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.

• 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.

• Architectural research
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• v.12 no.2
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• pp.93-98
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• 2010

This paper describes a numerical method for estimating the elastic moduli of cement paste. The cement paste is modeled as a unit cell which consists of three components: the unhydrated cement grain, the gel, and the capillary pore. In the unit cell, the volume fractions of the constituents are quantified using a single kinetic function calculating the degree of hydration. The elastic moduli of cement paste are calculated from the total displacements of constituents when a uniform pressure is applied to the gel contact area. The cement paste is assumed to be a homogenous isotropic matrix. Numerical simulations were conducted through the finite element analysis of the three-dimensional periodic unit cell. The model predictions are compared with experimental results. The predicted trends are in good agreement with experimental observations. This approach and some of the results might also be relevant for other technical applications.

• Journal of Korean Society of Water and Wastewater
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• v.11 no.2
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• pp.50-64
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• 1997

Life cycle assessment (LCA) on total sewage sludge treatment system from thickening to incineration and melting was performed for estimating global environmental impact as $CO_2$. In general, the life cycles of actual treatment facilities consist of construction, operation and dismantlement. In this study, the amount of $CO_2$ produced from both whole and each life cycle step of currently used unit sludge treatment processes were calculated by inventory analysis. In addition, in the all processes investigated in this study, individual $CO_2$ production unit (CPU), i.e. total produced $CO_2$ by treating a unit weight of sludge was also calculated. By using the CPU matrix of the unit processes, it was possible to simulate the $CO_2$ production for any type of complex-system as well as to trace a dominant cause of $CO_2$ production in each process. Four selected alternatives examined here, each involve the same disposal way but differ substantially in the $CO_2$ exhaust.

• Journal of The Korean Association For Science Education
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• v.23 no.3
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• pp.229-238
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• 2003

In this study, we investigated middle school student' ability in estimating order of magnitude of physical quantities. Participants were 448 students of seventh grades and ninth graders in Seoul area. A multiple-choice typed questionnaire was designed for estimating five physical quantities such as length, mass, speed, volume, and density. The answers were analyzed through dimension of quantity, size of object, students' grade and their gender. In the results, more than two thirds of all participants chose the right order of magnitude in estimating length, but only around a quarter of them did so in estimating density. They had a tendency to show lower ability when they estimated order of magnitude of more complex dimensioned quantity. Moreover, students' answers had relatively wide distribution in estimating smaller sized objects. Through there was no big difference between seventh graders and ninth graders in estimation, male students where better in estimating base quantities, especially in length. However, more than half of participants did not choose the right order of magnitude in total and it showed their lack of qualitative understanding about these physical quantities and meaningless usage of unit in measuring.

• Korean Journal of Construction Engineering and Management
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• v.7 no.5
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• pp.167-176
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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.

• Korean Journal of Construction Engineering and Management
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• v.12 no.3
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• pp.131-139
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• 2011

In this Study, the Cost of Public Facility Construction in the VE Cost Model, and the Progress of the Construction Site Management, and Cost due to the Lack of Cpatial Information in Dispute Cost Work Type Recognize the limits of Historical Information, and to Overcome the Perception of Cost and Space Systems Unit In the Process of Transition that Began Seeking Ways to Improve Through this Study, Different Parts of the Proposed Area of Construction Work Unit System, the Core of Calculating Hourly and Detailed Engineering Information and Cost Information Generated Extension to Configure the Construction Unit in Every Space, Every Work Unit System, All Materials That Make Up Work Unit System, Unit Labor Costs, And All of the Configuration Items Enables Precise And Multidimensional Understanding is That.

• Journal of Korean Society of Rural Planning
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• v.23 no.4
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• pp.39-48
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• 2017

National Institute of Environmental Research (NIER) has proposed new methodology for estimating unit load in order to overcome the limitations of past unit load based on short-term and local area based data. In the case of agricultural land, however, the results presented by NIER are still limited because of various agricultural activities and farmland characteristics. In this study, liquid manure treated paddy field and organic farming upland were selected for considering agricultural diversity. Four different methods for evaluating unit load were used for comparing previous research results. The results of different methods presented various trends compared with those of existing studies. Paddy field treated liquid manure was 1.3 times higher for T-N load and 3.1 times for T-P load than conventional paddy field. Conventional upland was 4.4 times higher for T-N load and 1.8 times higher for T-P load than organic farming upland. In the case of non-conventional farmland, this study showed different values with the unit loads presented by NIER. This implies that it is necessary to review and apply the unit loads considering various agricultural conditions when establishing environmental policy and rural planning.