Kim, Jonghyeob; Lee, Hyun Woo; Bender, William; Hyun, Chang-taek. (2018). Model for Collecting Replacement Cycles of Building Components: Hybrid Approach of Indirect and Direct Estimations. Journal Of Computing In Civil Engineering, 32(6).
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Abstract
Building maintenance, repair, and replacement (MR&R) costs are estimated to be two to three times larger than initial construction costs. Thus, it is important to accurately estimate and manage MR&R costs in the planning phase and/or design phase of a construction project based on life cycle cost analysis (LCCA). However, the nature of LCCA requires making necessary assumptions for the prediction and analysis of MR&R costs, and the reliability of the assumptions greatly impacts LCCA results. In particular, determining reasonable replacement cycles is especially important given that each replacement typically involves a significant amount of capital. However, conventional approaches largely focus on either collecting component-specific replacement cases or surveying expert opinions, both of which reduce the usability and reliability of replacement cycle data at an early stage. To overcome these limitations, this study aims to develop a replacement cycle collection model that can expedite the data collection by combining indirect estimations with direct estimations. The development of the model involves collecting replacement cases, developing replacement cycle and index estimation methods, and developing an algorithm to implement the suggested model. As a validation, the applicability and effectiveness of the model were illustrated and tested by using simulated cases based on 21 real-world facilities. This study makes a theoretical contribution to the body of knowledge by developing a replacement cycle data collection model based on long-term and macro perspectives. The developed model will also be of value to practitioners when they try to improve the reliability of their LCCA.
Keywords
Buildings (structures); Life Cycle Costing; Maintenance Engineering; Structural Engineering; Building Components; Building Maintenance; Planning Phase; Design Phase; Construction Project; Life Cycle Cost Analysis; Replacement Cycle Data Collection Model; Construction Costs; Lcca; Maintenance Repair And Replacement Cost; Service Life Prediction; Repair; Replacement; Replacement Cycles; Replacement Index; Database; Indirect Estimations
Lee, Hyun Woo; Harapanahalli, Bharat Anand; Nnaji, Chukwuma; Kim, Jonghyeob; Gambatese, John. (2018). Feasibility of Using QR Codes in Highway Construction Document Management. Transportation Research Record, 2672(26), 114 – 123.
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Abstract
Highway construction occasionally takes place in remote locations, making its document management challenging especially when frequent document revisions occur. With the recent advancement of smartphones and tablets, Quick Response (QR) codes can provide project teams rapid and reliable access to up-to-date documents required for field operations. As a result, the use of QR codes can lead to a reduced need for traveling or meeting for document revisions, and reduce the amount of hardcopy documents and storage space. Despite the potential for significant benefits, there have been few studies aimed at assessing the feasibility of using QR codes in highway construction. In response, the objective of the study was to investigate the benefits of and barriers to using QR codes in highway construction for document management. To conduct the study, first a multi-step process was used, involving an online survey and interviews, with a goal of determining the status quo of highway construction in terms of document management and mobile information technology (IT). The results indicate that hardcopy documentation is still the most prevalent form of document management in highway construction, and hence there is an opportunity for implementing QR codes in conjunction with mobile IT. In the second part of the study, a time study using a real-world infrastructure project was conducted based on three activities: detail look up, specification check, and version check. As a result, the study found statistical evidence that using QR codes can lead to significant time savings.
Keywords
Highway Planning; Information Services; Road Construction; Document Management; Field Operation; Highway Construction; Infrastructure Project; Online Surveys; Quick Response Code; Remote Location; Statistical Evidence
Nnaji, Chukwuma; Lee, Hyun Woo; Karakhan, Ali; Gambatese, John. (2018). Developing a Decision-Making Framework to Select Safety Technologies for Highway Construction. Journal Of Construction Engineering And Management, 144(4).
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Abstract
Highway construction has consistently reported relatively high fatality rates largely because of the considerable exposure of workers to live traffic. To address this anomaly, traffic control planners are tasked with making decisions geared toward reducing hazardous situations caused by transiting vehicles and construction equipment. The growing application of technologies to enhance worker safety should be considered during the traffic control planning process. In certain cases, decisions such as choosing among technology options are made using experiential individual knowledge without the application of scientific and systematic decision-making methods. Use of experience-based decision making in this context is largely the result of sparse literature on scientific methods of selecting between alternatives in highway construction work zones. By applying the Choosing by Advantages (CBA) decision-making method, a process that achieves sound and effective decisions, the current study aims to fill the gap in practice by proposing a decision-making framework that could enhance the value-cost selection process of safety technologies in highway construction work zones. A situation that applied work zone intrusion alert technologies (WZIATs) was selected as a case study. Using a focus group session and case projects as an evaluation study process, the proposed framework based on the CBA decision-making process was applied to evaluate three WZIATs. Findings from the current study will benefit safety professionals and practitioners by providing a step-by-step approach to make sound decisions that can enhance the level of safety in highway construction work zones.
Keywords
Construction Equipment; Decision Making; Occupational Safety; Project Management; Road Building; Effective Decisions; Decision-making Framework; Value-cost Selection Process; Highway Construction Work Zones; Work Zone Intrusion Alert Technologies; Cba Decision-making Process; Sound Decisions; Traffic Control Planners; Worker Safety; Traffic Control Planning Process; Technology Options; Scientific Decision-making Methods; Systematic Decision-making Methods; Experience-based Decision Making; Advantages Decision-making Method; Safety Technologies; Knowledge; Signs
Nnaji, Chukwuma; Gambatese, John; Lee, Hyun Woo. (2018). Work Zone Intrusion: Technology to Reduce Injuries & Fatalities. Professional Safety, 63(4), 36 – 41.
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Abstract
WZIAT was first introduced to work zones in 1995 following a Strategic Highway Research Program (SHRP)-sponsored study (Agent & Hibbs, 1996). Since the SHRP program, several WZIATs have been developed, evaluated by departments of transportation (DOTs) and implemented in work zones on many highway projects. [...]the researchers investigated the potential usefulness of WZIATs on reported fatal work zone intrusion cases. [...]the researchers identified and evaluated work zone fatality cases captured in the NIOSH Fatality Assessment and Control Evaluation (FACE) program to determine whether WZIATs could have prevented the reported fatalities. [...]construction and maintenance workers are provided additional reaction time if an intrusion occurs before the activity zone.
Keywords
Research; Fatalities; Highway Construction; Injury Prevention; Traffic Accidents & Safety; Automobile Safety; Roads & Highways; Transportation Planning; Electronic Mail Systems; Researchers; Intrusion; General Contractors; Occupational Health; Vehicles; Studies; Workers; Employees; Construction Industry; Traffic Control; United States--us; Canada; Kansas; Oregon
Park, Kyungmo; Lee, Hyun Woo; Choi, Kunhee; Lee, Seung-hyun. (2019). Project Risk Factors Facing Construction Management Firms. International Journal Of Civil Engineering, 17(3), 305 – 321.
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Abstract
Very little is known about the project risk factors that affect construction management (CM) firms, which often struggle due to a lack of effective risk management practices. This study investigates the risk factors critical to project execution in CM firms and ranks them using the analytic hierarchy process (AHP) and failure mode and effects analysis (FMEA) methods. Interviews with executives at the top 15 Korean CM firms are carried out to identify major risk factors in the CM sector, and a survey is used to develop priority ranking. We find that payment delays and project delays are the two most critical risk factors affecting CM firms because of (1) lack of communication between headquarters and field offices, (2) shift of responsibility from headquarters to a field office, (3) absence of regular monitoring of project progress, and (4) ex-post management practices. The findings presented in this study should assist CM firms in establishing more robust risk management practices, thereby improving firms' profitability, project performance, and customer satisfaction.
Keywords
Analytic Hierarchy Process; Customer Satisfaction; Factor Analysis; Risk Assessment; Risk Management; Analytic Hierarchy Process (ahp); Construction Management; Construction Management Firms; Failure Mode And Effects Analysis; Korea; Management Practices; Risk Factors; Risk Management Practices; Industry
Gomez-Cunya, Luis-Angel; Fardhosseini, Mohammad Sadra; Lee, Hyun Woo; Choi, Kunhee. (2020). Analyzing Investments in Flood Protection Structures: A Real Options Approach. International Journal Of Disaster Risk Reduction, 43.
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Abstract
The soaring number of natural hazards in recent years due largely to climate change has resulted in an even higher level of investment in flood protection structures. However, such investments tend to be made in the aftermath of disasters. Very little is known about the proactive planning of flood protection investments that account for uncertainties associated with flooding events. Understanding the uncertainties such as when to invest on these structures to achieve the most optimal cost-saving amount is outmost important. This study fills this large knowledge gap by developing an investment decision-making assessment framework that determines an optimal timing of flood protection investment options. It combines real options with a net present value analysis to examine managerial flexibility in various investment timing options. Historical data that contain information about river water discharges were leveraged as a random variable in the modeling framework because it may help investors better understand the probability of extreme events, and particularly, flooding uncertainties. A lattice model was then used to investigate potential alternatives of investment timing and to evaluate the benefits of delaying investments in each case. The efficacy of the proposed framework was demonstrated by an illustrative example of flood protection investment. The framework will be used to help better inform decision makers.
Keywords
Decision-making; Flood Protection; Real Options Theory; Investment Decision-making
Ho, Chung; Lee, Hyun Woo; Gambatese, John A. (2020). Application of Prevention Through Design (PTD) to Improve the Safety of Solar Installations on Small Buildings. Safety Science, 125.
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Abstract
As a viable, clean and renewable energy resource, solar energy has gained a significant interest in the US residential sector. Most solar systems are installed on rooftops to take advantage of available space and reduce land use. However, this installation environment also exposes workers to unique safety hazards related to existing roof conditions such as slippery roofing materials, irregular roof layouts, and steep roof slopes. Although Prevention through Design (ND) has been widely considered as an effective way to address safety issues during the design phase, little to no studies have applied ND to improve safety in solar energy installations. To fill this knowledge gap, this research aimed to investigate how, during the design phase, to address the safety concerns of solar workers when installing solar energy systems on residential buildings. Through a series of interviews, four case studies, and a seminar, seven solar ND attributes were identified: roofing materials, roof slopes, roof accessories, panel layouts, fall protection systems, lifting methods and electrical systems. Based on the attributes, a ND protocol was developed that can serve as guidance for implementing ND in solar installations. This paper presents the research activities and findings, and feedback gained from solar contractors through a seminar on the study. The study is expected to contribute to reducing safety hazards by implementing ND, help improve safety performance in solar installations on small residential buildings and support the promotion of safety in sustainable construction.
Keywords
Roofing Materials; Renewable Energy Sources; Sustainable Construction; Solar Energy; Clean Energy; Construction Safety; Prevention Through Design; Small Buildings; Solar Installations; Buildings (structures); Construction Industry; Hazards; Occupational Safety; Roofs; Safety; Solar Power; Sustainable Development; Steep Roof Slopes; Design Phase; Solar Energy Installations; Solar Workers; Installing Solar Energy Systems; Residential Buildings; Seven Solar Ptd Attributes; Roof Accessories; Ptd Protocol; Solar Contractors; Safety Performance; Viable Energy Resource; Clean Energy Resource; Renewable Energy Resource; Us Residential Sector; Solar Systems; Installation Environment; Unique Safety Hazards; Roof Conditions; Slippery Roofing Materials; Irregular Roof Layouts; Issues; Accident Prevention; Protocol; Energy Sources; Residential Areas; Land Use; Prevention; Design; Falls; Occupational Hazards; Contractors; Residential Energy; Protection Systems; Renewable Energy; Buildings; Roofing; Layouts
Hyun Woo Lee; Anderson, S.M.; Yong-Woo Kim; Ballard, G.. (2014). Advancing Impact of Education, Training, and Professional Experience on Integrated Project Delivery. Practice Periodical On Structural Design And Construction, 19(1), 8 – 14.
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Abstract
With the increased interest in applying integrated forms of project delivery to complex and uncertain construction projects, the building industry has been experiencing an increased demand for integrated project delivery (IPD). With the trend, many empirical studies have examined the collaborative characteristics of IPD and reported that participants must make the necessary transition for its contractual, technological, and cultural requirements. However, little study has been done to investigate relevant education, training, or professional experience that can support the transition. In response, this study used an online survey that was designed to investigate the level and type of education, training, and professional experience of project members and their corresponding level of background knowledge for each IPD requirement. The key survey findings include (1) project members have the highest level of background knowledge on the cultural requirements of IPD, but the lowest level on the technological requirements; (2) the group with more design-build experience has more background knowledge; (3) the group that received an IPD kick-off training has more background knowledge; and (4) having a lean construction class can prepare students for the IPD environment. It is expected that the survey findings will advance the education, training, and levels of background knowledge of IPD participants, which will enhance their IPD experience accordingly.
Keywords
Buildings (structures); Construction Industry; Contracts; Cultural Aspects; Industrial Training; Professional Aspects; Project Management; Construction Project; Building Industry; Integrated Project Delivery; Ipd; Contractual Requirement; Cultural Requirement; Professional Experience; Design-build Experience; Training Impact; Education Impact
Lee, Yong-Cheol; Shariatfar, Moeid; Rashidi, Abbas; Lee, Hyun Woo. (2020). Evidence-Driven Sound Detection for Prenotification and Identification Of Construction Safety Hazards and Accidents. Automation In Construction, 113.
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Abstract
As the construction industry experiences a high rate of casualties and significant economic loss associated with accidents, safety has always been a primary concern. In response, several studies have attempted to develop new approaches and state-of-the-art technology for conducting autonomous safety surveillance of construction work zones such as vision-based monitoring. The current and proposed methods including human inspection, however, are limited to consistent and real-time monitoring and rapid event recognition of construction safety issues. In addition, the health and safety risks inherent in construction projects make it challenging for construction workers to be aware of possible safety risks and hazards according to daily planned work activities. To address the urgent demand of the industry to improve worker safety, this study involves the development of an audio-based event detection system to provide daily safety issues to laborers and through the rapid identification of construction accidents. As an evidence-driven approach, the proposed framework incorporates the occupational injury and illness manual data, consisting of historical construction accident data classified by types of sources and events, into an audio-based safety event detection framework. This evidence-driven framework integrated with a daily project schedule can automatically provide construction workers with prenotifications regarding safety hazards at a pertinent work zone as well as consistently contribute to enhanced construction safety monitoring by audio-based event detection. By using a machine learning algorithm, the framework can clearly categorize the narrowed-down sound training data according to a daily project schedule and dynamically restrict sound classification types in advance. The proposed framework is expected to contribute to an emerging knowledge base for integrating an automated safety surveillance system into occupational accident data, significantly improving the accuracy of audio-based event detection.
Keywords
Construction Projects; Occupational Hazards; Construction Workers; Construction; System Safety; Video Surveillance; Work-related Injuries; Audio-based Accident Recognition; Autonomous Safety Surveillance; Construction Safety; Evidence-driven Sound Event Detection; Accident Prevention; Accidents; Audio Acoustics; Classification (of Information); Construction Industry; Health Hazards; Health Risks; Knowledge Based Systems; Learning Algorithms; Losses; Machine Learning; Monitoring; Motion Compensation; Occupational Diseases; Steel Beams And Girders; Audio-based; Construction Accidents; Construction Work Zones; Historical Construction; Sound Event Detection; State-of-the-art Technology; Vision Based Monitoring; Algorithm; System
Shakouri, Mahmoud; Lee, Hyun Woo; Choi, Kunhee. (2015). PACPIM: New Decision-Support Model of Optimized Portfolio Analysis for Community-Based Photovoltaic Investment. Applied Energy, 156, 607 – 617.
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Abstract
Inherent in large-scale photovoltaic (PV) investments is volatility that stems from a unique set of spatial factors, such as shading, building orientation, and roof slope, which can significantly affect both the level of risk and the return on investment. In order to systematically assess and manage the volatility, this study seeks to create a quantitative decision-support model: Portfolio Analysis for Community-based PV Investment Model (PACPIM). Focusing on residential PV systems, PACPIM determines optimized portfolios by applying the Mean Variance Portfolio theory. The model is intended to play an instrumental role in: (1) maximizing the hourly electricity output of PV systems; (2) minimizing the hourly volatility in electricity output; and (3) optimizing the risk-adjusted performance of community-based PV investment. The application and framework of PACPIM were deployed with an actual residential community consisting of 24 houses and their simulated data utilizing PVWatts (R) for estimating hourly electricity production. Results reveal that the optimized portfolios developed by PACPIM (1) increased annual electricity output of PV systems by 4.6%; (2) reduced the volatility in electricity output by 4.3%; and (3) offered the highest risk-adjusted performance among all possible portfolios based on the Sharpe ratios. This study is expected to effectively assist project owners and investors in systematically assessing their community-based PV projects and in developing optimized investment strategies. (C) 2015 Elsevier Ltd. All rights reserved.
Keywords
Photovoltaic Cells; Rate Of Return; Electricity; Dwellings; Electric Utilities; Community-based Investments; Decision-support Model; Mean–variance Portfolio Theory; Residential Photovoltaic Systems; Solar Energy; Decision Support Systems; Investment; Photovoltaic Power Systems; Large-scale Photovoltaic Investments; Spatial Factors; Shading; Building Orientation; Roof Slope; Return On Investment; Quantitative Decision-support Model; Portfolio Analysis For Community-based Pv Investment Model; Pacpim; Residential Pv Systems; Mean-variance Portfolio Theory; Hourly Electricity Output; Hourly Volatility; Risk-adjusted Performance; Hourly Electricity Production Estimation; Community-based Pv Projects; Optimized Investment Strategies; Romanian National Strategy; Renewable Energy; Public-attitudes; Wind Power; Pv Module; Performance; Implementation; Efficiency; Form; Economic Theory; Electricity Generation; Models; Risk; Shade; Solar Collectors