Kim, Taehoon; Kim, Yong-woo; Lee, Dongmin; Kim, Minju. (2022). Reinforcement Learning Approach To Scheduling Of Precast Concrete Production. Journal Of Cleaner Production, 336.
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Abstract
The production scheduling of precast concrete (PC) is essential for successfully completing PC construction projects. The dispatching rules, widely used in practice, have the limitation that the best rule differs according to the shop conditions. In addition, mathematical programming and the metaheuristic approach, which would improve performance, entail more computational time with increasing problem size, let alone its models being revised as the problem size changes. This study proposes a PC production scheduling model based on a reinforcement learning approach, which has the advantages of a general capacity to solve various problem conditions with fast computation time and good performance in real-time. The experimental study shows that the proposed model outperformed other methods by 4-12% of the total tardiness and showed an average winning rate of 77.0%. The proposed model could contribute to the successful completion of off-site construction projects by supporting the stable progress of PC construction.
Keywords
Precast Concrete; Reinforcement Learning; Deep Q -network; Production Scheduling; Minimize; Model
Kang, Goune; Kim, Taehoon; Kim, Yong-woo; Cho, Hunhee; Kang, Kyung-in. (2015). Statistical Analysis of Embodied Carbon Emission for Building Construction. Energy And Buildings, 105, 326 – 333.
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Abstract
Buildings are significant contributors to the greenhouse effect through emission of considerable carbon dioxide during their life cycle. Life cycle carbon resulting from buildings consists of two components: operational carbon (OC) and embodied carbon (EC). Recent studies have shown the growing significance of EC because much effort has already been invested into reducing OC. In this context, it is important to estimate and reduce EC. Because of the variability and uncertainty contained in a range of conditions, the EC of building needs to be calculated based on probabilistic analysis. This study identifies and analyzes the statistical characteristics of EC emitted from building construction materials. It was aimed at buildings constructed of reinforced concrete and nine representative construction materials. Descriptive statistics analysis, correlation analysis, and a goodness-of-fit test were performed to describe the statistical characteristics of EC. In addition, a case study was carried out to show the difference between the deterministic and probabilistic estimations. Presenting statistical information on EC data and the differences between the deterministic and probabilistic values, the result shows the necessity and reasonability of the probabilistic method for EC estimation. (C) 2015 Published by Elsevier B.V.
Keywords
Construction; Construction Materials; Greenhouse Gases; Probability Theory; Goodness-of-fit Tests; Quantitative Research; Building Materials; Correlation; Descriptive Statistics; Embodied Carbon; Goodness-of-fit; Buildings (structures); Reinforced Concrete; Statistical Analysis; Embodied Carbon Emission; Greenhouse Effect; Carbon Dioxide; Life Cycle Carbon; Operational Carbon; Oc; Probabilistic Analysis; Building Construction Materials; Statistics Analysis; Correlation Analysis; Probabilistic Estimations; Statistical Information; Ec Data; Probabilistic Method; Ec Estimation; Life-cycle; Energy Measurement; System Boundary
Kim, Sang-chul; Kim, Yong-woo; Park, Kun Soo; Yoo, Choong-yuel. (2015). Impact of Measuring Operational-Level Planning Reliability on Management-Level Project Performance. Journal Of Management In Engineering, 31(5).
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Abstract
The earned value management system (EVMS) and the last planner system (LPS) have been widely used as effective performance measurement tools for construction managers and production units at construction projects. While the EVMS measures project-level costs and scheduling performances, the LPS measures the percent plan complete (PPC), which indicates the level of planning reliability. This paper investigates the relationship between planning reliability at the operational level and project performance at the management level (i.e., the success or failure of a project). Analyzing the empirical data of 23 residential projects of a large construction company, the authors find that, while the production plan in the weekly schedule is correlated rigidly with the daily plan in successful projects, such a rigid correlation is not observed in unsuccessful projects. To understand this finding, the authors further conducted interviews with project stakeholders. Taken together, this study suggests that an emphasis on LPS indices causes subcontractors to engage in myopic behaviors such as modifying operational-level indices. Consequently, management-level production plan rigidity is at risk. The findings in this paper offer valuable insights and help project stakeholders understand the attributes of operational-level and management-level indices and their relationships. (C) 2014 American Society of Civil Engineers.
Keywords
Construction Industry; Costing; Production Planning; Project Management; Reliability; Scheduling; Subcontracting; Construction Projects; Production Units; Myopic Behaviors; Project Stakeholders; Subcontractors; Production Plan; Percent Plan Completion; Scheduling Performances; Project-level Costs; Performance Measurement Tools; Construction Managers; Last Planner System; Earned Value Management System; Management-level Project Performance; Evms; Operational-level Planning Reliability; Balanced Scorecard; Lean Construction; Contractors; Indexes; Design; Model; Earned Value; Lean; Construction; Schedule Performance Index; Cost Performance Index; Percent-plan-completion; Empirical Analysis
Azari, Rahman; Kim, Yong-Woo. (2016). Integration Evaluation Framework for Integrated Design Teams of Green Buildings: Development and Validation. Journal Of Management In Engineering, 32(3).
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Abstract
Integrated design (ID) process encourages integration of team members in the design phase of green building projects through intense collaborative processes and free exchange of information. Although integration in general and ID in particular have been well theorized by construction management research community, there exists no systematic mechanism in the field to help owners, architects, and managers of green project teams assess the level of integration in their projects' ID team environment in a practical manner. The key objective of the present article is therefore to use a qualitative-quantitative methodology to propose and validate an integration evaluation framework for green project teams and to statistically test the association between integration level and project success. The framework can be used by green project teams for comparison, benchmarking, or educational purposes and for integration evaluation and improvement in ID team environments. This research also provides empirical evidence to anecdotes suggesting positive link between team integration and project success in green projects.
Keywords
Architecture; Benchmark Testing; Buildings (structures); Construction Industry; Education; Information Management; Process Design; Project Management; Statistical Testing; Team Working; Integration Evaluation Framework; Integrated Design Process; Team Members; Green Building Project; Construction Management Research Community; Architect; Id Team Environment; Benchmarking; Educational Purpose; Information Exchange; Construction; Delivery; Evaluation; Integration; Integrated Design; Green Buildings; Validation; Context; Input; Process; And Product (cipp)
Kim, Byung-soo; Kim, Yong-woo. (2016). Configuration of Earthwork Equipment Considering Environmental Impacts, Cost and Schedule. Journal Of Civil Engineering And Management, 22(1), 73 – 85.
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Abstract
Along with promotion of public awareness about sustainability, the concept of sustainability has gained in- creasing attention across all industries. The construction industry is one of the largest industries, and at the same time, among the largest polluters. Thus, the concept of sustainability has become increasingly important to construction firms and many contractors have started to reduce the environmental impacts of their construction activities. As part of the effort to achieve sustainability in construction sector, the study develops a method to select earth-moving equipment, based on their environmental impacts as well as duration and cost considerations. To this end, the study initially devel- ops a model for determining construction costs and duration as well as a model for determining monetary environmental impacts on earthwork construction. The study then uses an Improved Weight Decision Method (IWDM) to determine the weight of variables in order to find the best performed equipment configuration. The authors expect that the findings of the study will contribute to the research and practice in configuring earthwork equipment, taking into account associated environmental impacts as well as time and costs.
Keywords
Earthwork; Environmental Impact Analysis; Sustainable Development; Production Scheduling; Cost Analysis; Earthwork Equipment; Environmental Impacts; Equipment Configuration; Improved Weight Decision Method (iwdm); Construction Activities; Construction Costs; Construction Firms; Construction Sectors; Cost And Schedule; Decision Method; Public Awareness; Construction Equipment; Construction Industry; Excavation; Foundations; 0
Kim, Taehoon; Kim, Yong-woo; Cho, Hunhee. (2016). Customer Earned Value: Performance Indicator from Flow and Value Generation View. Journal Of Management In Engineering, 32(1).
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Abstract
The earned value method (EVM) is considered an advanced project control technique that provides a quantitative measure of work performance. However, the EVM is effective only under the assumption that every activity is independent. Literature shows that the EVM lacks the value generation view even working against the reliability of workflow. The goal of this research is to propose a project metric system to supplement the EVM in terms of the workflow and value generation. The researchers suggest a new metric of customer earned value (CEV), which is defined as the budgeted amount of work completed and is used by the successors on a network. Through a hypothetical case study, this research investigates how the work-in-process between trades and schedule performance in each trade behave under different uncertainties. The result suggests that the proposed metrics can provide project managers with more relevant managerial information on project progress as well as on the level of collaboration. The proposed system with the EVM would facilitate collaboration on project planning and control where variability and interdependency are involved. (C) 2015 American Society of Civil Engineers.
Keywords
Budgeting; Customer Services; Organisational Aspects; Planning; Project Management; Customer Earned Value; Project Planning; Project Managers; Trade-schedule Performance; Work-in-process; Budgeted Amount; Project Metric System; Advanced Project Control Technique; Earned Value Method; Performance Indicator; Value Generation View; Management; Project Control Metric; Collaboration
Park, Hyoungbae; Kim, Kyeongseok; Kim, Yong-woo; Kim, Hyoungkwan. (2017). Stakeholder Management in Long-Term Complex Megaconstruction Projects: The Saemangeum Project. Journal Of Management In Engineering, 33(4).
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Abstract
This paper identifies 31 critical success factors (CSFs) and suggests a framework for effective stakeholder management in long-term complex megaconstruction (LCM) projects that require more than 10 years for multipurpose development. The results of a survey on the prioritization of these 31 CSFs reveal that LCM projects involve more stakeholders than do general construction projects and require a correspondingly wider range of changes during each project. To identify more systematic and strategic approaches to stakeholder management in LCM projects, a framework was developed through factor analysis and focus-group interviews with project management experts. The framework is composed of the following five agendas: clear understanding of stakeholders, clear definition of the project, effective communication, responding to environmental changes, and social cooperation. The analysis results show that LCM projects require a stronger emphasis on responding to environmental changes and social cooperation. These results, along with the CSF priorities, reveal the necessity of taking customized approaches to LCM projects. The results of this analysis are expected to help LCM project managers effectively manage stakeholders. (C) 2017 American Society of Civil Engineers.
Keywords
Construction; Environmental Management; Project Management; Strategic Planning; Social Cooperation; Environmental Changes; Strategic Approaches; Construction Projects; Saemangeum Project; Long-term Complex Megaconstruction Projects; Stakeholder Management; Critical Success Factors (csfs); Long-term Complex Megaconstruction (lcm) Projects
Shakouri, Mahmoud; Lee, Hyun Woo; Kim, Yong-woo. (2017). A Probabilistic Portfolio-Based Model for Financial Valuation of Community Solar. Applied Energy, 191, 709 – 726.
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Abstract
Community solar has emerged in recent years as an alternative to overcome the limitations of individual rooftop photovoltaic (PV) systems. However, there is no existing model available to support probabilistic valuation and design of community solar based on the uncertain nature of system performance over time. In response, the present study applies the Mean-Variance Portfolio Theory to develop a probabilistic model that can be used to increase electricity generation or reduce volatility in community solar. The study objectives include identifying the sources of uncertainties in PV valuation, developing a probabilistic model that incorporates the identified uncertainties into portfolios, and providing potential investors in community solar with realistic financial indicators. This study focuses on physical, environmental, and financial uncertainties to construct a set of optimized portfolios. Monte Carlo simulation is then performed to calculate the return on investment (ROI) and the payback period of each portfolio. Lastly, inclusion vs. exclusion of generation and export tariffs are compared for each financial indicator. The results show that the portfolio with the maximum output offers the highest ROI and shortest payback period while the portfolio with the minimum risk indicates the lowest ROI and longest payback period. This study also reveals that inclusion of tariffs can significantly influence the financial indicators, even more than the other identified uncertainties. (C) 2017 Elsevier Ltd. All rights reserved.
Keywords
Solar Energy; Photovoltaic Power Systems; Monte Carlo Method; Market Volatility; Energy Economics; Community Solar; Monte Carlo Simulation; Photovoltaic Systems; Portfolio Theory; Uncertainty; Environmental Uncertainties; Financial Indicator; Financial Uncertainties; Physical Uncertainties; Identified Uncertainties; Probabilistic Model; Mean-variance Portfolio Theory; Probabilistic Valuation; Individual Rooftop Photovoltaic Systems; Financial Valuation; Probabilistic Portfolio-based Model; Investment; Monte Carlo Methods; Photovoltaic Cells; Risk Analysis; Tariffs; Resolution Lidar Data; Electricity Consumption; Pv Systems; Autoregressive Models; Potential Assessment; Generation Systems; Neural-networks; Energy; Buildings; Economic Theory; Electricity; Exports; Probabilistic Models; Risk
Yi, June-seong; Kim, Yong-woo; Lim, Ji Youn; Lee, Jeehee. (2017). Activity-Based Life Cycle Analysis of a Curtain Wall Supply for Reducing Its Environmental Impact. Energy And Buildings, 138, 69 – 79.
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Abstract
Life-Cycle Assessment has been used extensively in the construction industry to assess the environmental impacts of building materials. Attributional LCA considers processes in a supply chain which allows users to identify a process to improve to minimize the environmental impacts. However, the level of detail adopted in traditional attributional LCA is aggregate, not appropriate for process improvement efforts in the construction project context which is characterized as a complex system. This paper proposes Activity-based LCA (ABLCA) which adopts the methodology of the activity-based costing system to carry out the assessment and analysis of environmental impacts for the life cycle. The research carried out a case study on the curtain wall supply chain. The outcome of inventory analysis for each activity and environmental impact assessment showed the curtain wall supply chain process made an impact on five environmental impact categories: global warming air, acidification air, HH criteria air; eutrophication air, and photochemical smog air. With comparison to the outcome of environmental impact assessment from existing LCA, the proposed management system to investigate environmental impacts was addressed. The proposed ABLCA enables management to develop an environmental-impacts-reduction plan focusing on critical activities. (C) 2016 Elsevier B.V. All rights reserved.
Keywords
Construction Industry & The Environment; Energy Conservation In Construction Industry; Building Materials & The Environment; Complexity (philosophy); Global Warming & The Environment; Activity-based Management; Attributional Lca (life-cycle Assessment); Curtain Wall; Environmental Impacts; Activity-based Life Cycle Analysis; Ablca; Construction Industry; Building Materials; Inventory Analysis; Life-cycle Assessment; Environmental Impact Categories; Curtain Wall Supply Chain Process; Environmental Impact Assessment; Environmental-impacts-reduction Plan; Environmental Factors; Inventory Management; Life Cycle Costing; Product Life Cycle Management; Supply Chain Management; Walls; United-states; Performance; Buildings; Energy; Trends; Lca; Environmental Impact; Supply Chains; Environmental Assessment; Construction Materials; Life Cycle Engineering; Eutrophication; Life Cycle Analysis; Construction; Climate Change; Global Warming; Smog; Life Cycle Assessment; Case Studies; Cost Analysis; Acidification; Photochemical Smog; Environmental Management; Life Cycles
Kim, Yong-Woo. (2019). The Impact of Make-Ready Process on Project Cost Performance in Heavy Civil Construction Projects. Production Planning & Control. The Management Of Operations, 30(13), 1064 – 1071.
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Abstract
The research investigates the relationship between the production plan reliability and the project cost performance using project data in the heavy civil construction sector. The research also investigates the attributes of a make-ready process using the statistical analysis. This study shows that production planning reliability (i.e. Per cent Constraint Removal (PCR) and Per cent Plan Complete (PPC)) and project cost performance (CPI) are significantly correlated in the heavy construction projects. The findings show that there is a more significant correlation between production planning reliability and project cost performance in project-scaled data than in monthly scaled data. They suggest that there is a time-lag between when the variance of workflow occurs and when the workflow variance impacts on the project cost performance. The result of the analysis also shows that the measure of make-ready process, PCR, has a more significant correlation with the project cost performance than the measure of weekly plan reliability, PPC.
Keywords
Construction Equipment; Construction Industry; Production Planning; Statistical Analysis; Heavy Construction Projects; Production Planning Reliability; Project Data; Production Plan Reliability; Civil Construction Projects; Make-ready Process; Project Cost Performance; Project-scaled Data; Construction Planning; Ppc (per Cent Plan Complete); Pcr (per Cent Constraints Removal)