• Title/Summary/Keyword: Estimation CBR

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A METHOD OF REVISING RETRIEVED SIMILAR CASES IN GA-CBR COST MODELS

  • Sooyoung Kim;Hyun-Soo Lee;Moonseo Park;Sae-Hyun Ji;Joseph Ahn
    • International conference on construction engineering and project management
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    • 2011.02a
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    • pp.182-186
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    • 2011
  • Early cost estimates are important to decision-making for a construction project. Moreover, the possibility of reducing the project cost is getting less as the project is progressed. Case-based reasoning (CBR), which can be viewed as an effective method for early cost estimating, is widely utilized recently. Early cost estimates using CBR have advantages over the traditional ones as they produce reasonable outputs and self-studying is possible by simply adding new cases. Case-based reasoning is composed of a cycle of retrieve, reuse, revise, and retain process. However, in the majority of research cases, they are focused on how to retrieve the similar cases, instead of revising the cases which is expected to increase accuracy results of cost estimation. This research suggests a method of revising retrieved similar cases in a GA-CBR cost model which is widely studied and utilized for early cost estimating recently. To validate the proposed method, case study is conducted based on Korean public apartment projects.

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ESTIMATING COSTS DURING THE INITIAL STAGE OF CONCEPTUAL PLANNING FOR PUBLIC ROAD PROJECTS: CASE-BASED REASONING APPROACH

  • Seokjin Choi;Donghoon Yeo;Seung H. Han
    • International conference on construction engineering and project management
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    • 2009.05a
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    • pp.1183-1188
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    • 2009
  • Estimating project costs during the early stage of conceptual planning is very important when deciding whether to approve the project and allocate an appropriate budget. However, due to greater uncertainties involved in a project, it is challenging to estimate costs during this initial stage within a reasonable tolerance. This paper attempts to develop a cost-estimate model for public road projects under these circumstances and limitations. In the conceptual planning stage of a road project, there is only limited information for cost estimation, for example, such input data as total length of the route, origin and destination, number of lanes, general geographic characteristics of the route, and other basic attributes. This implies that the model should individuate suitable but restricted information without considering detailed features such as quantity of earthwork and a detailed route of a given condition. With these limited facts, this paper applies a case-based reasoning (CBR) method to solve a new problem by deriving similar past problems, which in turn is used to estimate the cost of a given project based on best-fitted previous cases. To develop a CBR cost-estimate model, the authors classified 8 representative variables, including project type, the number of lanes, total length, road design grades, etc. Then, we developed the CBR model, primarily by using 180 actual cases of public road projects, procured over the last decade. With the CBR model, it was found that the degree of error in estimation can be reasonably reduced, to below approximately 30% compared to the final costs estimated upon the completion of detailed design.

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Application of The Dynamic Cone Penetrometer for Strength Estimation of Pavement Foundation (현장에서의 동적관입시험을 이용한 노상토의 지지력 평가연구)

  • An, Ji-Hwan;Yang, Sung-Lin;Park, Hee-Mun;Kwon, Su-Ahn
    • International Journal of Highway Engineering
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    • v.6 no.3 s.21
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    • pp.17-26
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    • 2004
  • The in-situ California Bearing Ratio (CBR) test has been widely used for evaluating the subgrade condition in asphalt concrete pavements. However, because the in-situ CBR test is expensive and takes plenty of time for operation, it is very difficult to figure out the in-situ characteristics of subgrade strength in detail. For faster and economical operation, the Dynamic Cone Penetrometer (DCP) has been often utilized for estimating the subgrade strength in the field. The relationship between the CBR value and DCP index obtained from the DCP testing has been studied using the laboratory and in-situ testing by other foreign researchers. The objective of this study is to determine the relationship between in-situ CBR value and DCP index of the subgrade materials used in Korea. The DCP index for evaluating the strength of subgrade materials produced in Korea is presented in this paper. Research results propose the regression equation to explain the relationship between the CBR and DCP tests. The in-situ CBR values of subgrade materials range from 20 to 45% indicating the good and sound subgrade condition.

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Parameter Impact Applied Case-based Reasoning Cost Estimation

  • Joseph Ahn;Hyun-Soo Lee;Moonseo Park;Sae-Hyun Ji;Sooyoung Kim
    • International conference on construction engineering and project management
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    • 2013.01a
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    • pp.475-478
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    • 2013
  • To carry out a one-off construction project successfully, effective and accurate early cost estimation is crucial, especially during the conceptual stage where very limited minimum information of construction project is given. As the level of accuracy of the early cost estimation has huge impacts on precise budgeting and cost management of a project, in other words, reducing the risk of a project, cost must be managed with special awareness. In an effort to improve the estimate accuracy of cost during the conceptual stage, this research introduces a Parameter Impact (PI) which can quantify weights of parameters and rank them; and PI development derived from the principle of impulse in physics is explicated. For a case study, 76 public apartment building cases in Korea are analyzed. To examine the validity of the proposed PI, a validation in terms of CBR applicability test and estimate accuracy comparisons using 10-nearest neighbor cases are carried out. The validation results support that the suggested PI can be applied in quantifying the weights of the parameters and CBR method for early cost estimation.

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Schematic Cost Estimation Method using Case-Based Reasoning: Focusing on Determining Attribute Weight (사례기반추론을 이용한 초기단계 공사비 예측 방법: 속성 가중치 산정을 중심으로)

  • Park, Moon-Seo;Seong, Ki-Hoon;Lee, Hyun-Soo;Ji, Sae-Hyun;Kim, Soo-Young
    • Korean Journal of Construction Engineering and Management
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    • v.11 no.4
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    • pp.22-31
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    • 2010
  • Because the estimated cost at early stage has great influence on decisions of project owner, the importance of early cost estimation is increasing. However, it depends on experience and knowledge of the estimator mainly due to shortage of information. Those tendency developed into case-based reasoning(CBR) method which solves new problems by adapting previous solution to similar past problems. The performance of CBR model is affected by attribute weight, so that its accurate determination is necessary. Previous research utilizes mathematical method or subjective judgement of estimator. In order to improve the problem of previous research, this suggests CBR schematic cost estimation method using genetic algorithm to determine attribute weight. The cost model employs nearest neighbor retrieval for selecting past case. And it estimates the cost of new cases based on cost information of extracted cases. As the result of validation for 17 testing cases, 3.57% of error rate is calculated. This rate is superior to accuracy rate proposed by AACE and the method to determine attribute weight using multiple regression analysis and feature counting. The CBR cost estimation method improve the accuracy by introducing genetic algorithm for attribute weight. Moreover, this makes user understand the problem-solving process easier than other artificial intelligence method, and find solution within short time through case retrieval algorithm.

Development of Approximate Cost Estimation System Based on CBRT echnique; Applicability Study for Landfarming Soil Remedation Technology (사례기반추론을 이용한 개략비용 예측시스템 개발 - 토양경작법 정화비용사례를 중심으로 적용가능성 검토 -)

  • Kim, Sang-Tae;Shim, Jin-Ah;Kim, Heung-Rae
    • Korean Journal of Construction Engineering and Management
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    • v.17 no.1
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    • pp.3-9
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    • 2016
  • This study proposes a approximate cost estimation system based on Excel with VBA using weighted CBR(Case Based Reasoning). One characteristic of this system is that it generates the sheet automatically as many as the number of similar case and new estimation when it performs a case learning and a new estimate and cell formula is automatically entered into each sheet. User can be free to compose a combination of attribute factors because they can select up to ten attribute factors. This paper presents an applicability of estimation model for estimating the soil remediation cost when it use a landfarming method. When compared to a estimation model by using average unit cost and optimum multiple regression, this model shows a better result. This study was aimed at landfarming method, but it is expected that a cost estimation model using CBR will be more likely to apply in soil remediation technologies which various remediation technologies and pollutant species exist.

Roadway Preliminary Cost Estimation Prototype based on BIM and GIS (BIM/GIS 기반 도로 개략공사비 산정 프로토타입 연구)

  • Park, Wonyoung;Kang, Tai-Kyung;Lee, Yoo-Sub
    • Korean Journal of Construction Engineering and Management
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    • v.14 no.6
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    • pp.14-21
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    • 2013
  • While a detailed cost estimation utilizes the comprehensive quantity information obtained from a complete drawing and specification, an approximate cost estimation heavily relies on the subjective decisions. This phenomenon is because the approximate estimation is usually conducted in early stage of the construction phase where the drawing and specification are not available. This study developed a roadway construction cost estimation system which enables users to estimate the approximated cost of the project in early stage. The system identifies the variation of the construction costs due to the road route change using a cased based reasoning(CBR) method. Overall the system is expected to improves the accuracy and effectiveness of the estimation process, because it would provide users with increased accessability and consistent results in early stage of the project which leaded to the increased work transparency.

Estimation of CTD and Peak-to-Peak CDV Allocation to Nodes in Domestic Region (국내영역에서 셀전달지연 추정 및 peak-to-peak CDV 노드별 할당)

  • Park, Chun-Kwan;Han, Jong-Seok
    • Journal of the Institute of Electronics Engineers of Korea TC
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    • v.38 no.2
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    • pp.6-12
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    • 2001
  • When CBR source traffics are loaded to ATM switch and broadband network termination, CTD values of ATM switch and broadband network termination are measured and then the values of CTD in the domestic region arc estimated. The estimation values of CTD satisfy the objective of CTD in the domestic region allocated by allocation rules of 1.356. The peak-to-peak CDV allocation method based On Chernoff accumulation method is proposed and applied to the nodes of national portion. From the result of numerical analysis, the proposed method is more accurate than the equal allocation method for peak -to-peak CDV in case that the CDVs at each node and the number of ATM nodes on the path increase.

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A Study on the Prediction of Recycled Aggregate Concrete Strength Using Case-Based Reasoning and Artificial Neural Network (사례기반 추론과 인공신경망을 적용한 순환골재콘크리트 강도 추정에 관한 비교 연구)

  • Kim Dae-Won;Choi hee-Bok;Kang Kyung-In
    • Proceedings of the Korean Institute of Building Construction Conference
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    • 2005.05a
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    • pp.119-124
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    • 2005
  • It is necessary for prediction of recycled aggregate concrete(RAC) strength at the early stage that facilitate concrete form removal and scheduling for construction. However, to predict RAC strength is difficult because of being influenced by complicated many factors. Therefore, this research suggest optimized estimation method that can reflect many factors. One way is Case-Based Reasoning(CBR) that solved new problems by adapting solutions to similar problems solved in the past, which are solved in the case library. Other way is Artificial Neural Networks(ANN) that solved new problems by training using a set of data, which is representative of problem domain. This study is to propose comparing accuracy of the estimating the compressive strength of recycled aggregate concrete using Case-Based Reasoning(CBR) and Artificial Neural Networks(ANN).

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Cost Estimation of Case-Based Reasoning Using Hybrid Genetic Algorithm - Focusing on Local Search Method Using Correlation Analysis - (혼합형 유전자 알고리즘을 적용한 사례기반추론 공사비예측 - 상관분석을 이용한 지역탐색 기법을 중심으로 -)

  • Jung, Sangsun;Park, Moonseo;Lee, Hyun-Soo;Yoon, Inseok
    • Korean Journal of Construction Engineering and Management
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    • v.21 no.1
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    • pp.50-60
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    • 2020
  • Estimates of project costs in the early stages of a construction project have a significant impact on the operator's decision-making in important matters, such as the site's decision or the construction period. However, it is difficult to carry out the initial stage with confidence because information such as design books and specifications is not available. In previous studies, case-based reasoning was used to predict initial construction costs, and genetic algorithms were used to calculate the weight of the inquiry phase among them. However, some say that it is difficult to perform better than the current year because existing genetic algorithms are calculated in random numbers. To overcome these limitations, correlation numbers using correlation analysis rather than random numbers are reflected in the genetic algorithm by method of local search, and weights are calculated using a hybrid genetic algorithm that combines local search and genetic algorithms. A case-based reasoning model was developed using the weights calculated and validated with the data. As a result, it was found that the hybrid GA-CBR applied with local search performed better than the existing GA-CBR.