Kim, Taehoon; Kim, Yong-Woo; Cho, Hunhee. (2021). A Simulation-Based Dynamic Scheduling Model for Curtain Wall Production Considering Construction Planning Reliability. Journal Of Cleaner Production, 286.
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Abstract
Appropriate production scheduling of curtain wall systems is essential for the successful completion of construction projects. The construction process of the curtain wall system is mainly on the critical path and accounts for 10-15% of the total construction cost. Should curtain wall products not be timeously delivered to the construction site, construction projects are likely to fall behind schedule with most relevant activities on curtainwall installation on a critical path. However, due-date uncertainty caused by a contractor's lack of planning reliability causes the curtain wall production schedule to become complex and changes the due date after the initial order. In this regard, this study proposes a discrete event simulation-based dynamic scheduling model for curtain wall production to deliver products on time to the construction site by considering each construction project's planning reliability. Through simulation experiments, the validity and effectiveness of the proposed model were tested. The results of this study will help the successful completion of construction projects by ensuring the progress of the curtain wall system construction and follow-up activities following the construction schedule. (C) 2020 Elsevier Ltd. All rights reserved.
Keywords
Construction Industry; Discrete Event Simulation; Dynamic Scheduling; Production Control; Production Planning; Project Management; Reliability; Scheduling; Walls; Construction Planning Reliability; Construction Schedule; Curtain Wall System Construction; Construction Project; Discrete Event Simulation-based Dynamic Scheduling Model; Curtain Wall Production Schedule; Curtain Wall Installation; Curtain Wall Products; Total Construction Cost; Critical Path; Production Scheduling; Off-site Construction; Demand Variability; Job Shops; Precast; Minimize; Number; Curtain Wall; Simulation; Planning Reliability; Dispatching Rule
Shen, Qing; Wang, Yiyuan; Gifford, Casey. (2021). Exploring Partnership Between Transit Agency And Shared Mobility Company: An Incentive Program For App-based Carpooling. Transportation, 48(5), 2585 – 2603.
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Abstract
How should public transit agencies deliver mobility services in the era of shared mobility? Previous literature recommends that transit agencies actively build partnerships with mobility service companies from the private sector, yet public transit agencies are still in search of a solid empirical basis to help envision the consequences of doing so. This paper presents an effort to fill this gap by studying a recent experiment of shared mobility public-private partnership, the carpool incentive fund program launched by King County Metro in the Seattle region. This program offers monetary incentives for participants who commute using a dynamic app-based carpooling service. Through descriptive analysis and a series of logistic regression models, we find that the monetary incentive to encourage the use of app-based carpooling generates some promising outcomes while having distinctive limitations. In particular, it facilitates the growth of carpooling by making carpooling a competitive commuting option for long-distance commuters. Moreover, our evidence suggests that the newly generated carpooling trips mostly substitute single-occupancy vehicles, thus contributing to a reduction of regional VMT. The empirical results of this research will not only help King County Metro devise its future policies but also highlight an appealing alternative for other transit agencies in designing an integrated urban transportation system in the era of shared mobility.
Keywords
Shared Mobility; Public-Private Partnership; App-based Carpooling; Incentive Fund; Transit Agencies; Incentives; Commuting; Public Transportation; Mobility; Regression Analysis; Regression Models; Partnerships; Vehicles; Car Pools; Private Sector; Occupancy; Transportation Systems; Mass Transit; Transportation Planning; Empirical Analysis; Urban Transportation
Chen, Chen; Lindell, Michael K.; Wang, Haizhong. (2021). Tsunami Preparedness and Resilience in the Cascadia Subduction Zone: A Multistage Model of Expected Evacuation Decisions and Mode Choice. International Journal Of Disaster Risk Reduction, 59.
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Abstract
Physical scientists have estimated that the Cascadia Subduction Zone (CSZ) has as much as a 25% chance to produce a M9.0 earthquake and tsunami in the next 50 years, but few studies have used survey data to assess household risk perceptions, emergency preparedness, and evacuation intentions. To understand these phenomena, this study conducted a mail-based household questionnaire using the Protective Action Decision Model (PADM) as a guide to collect 483 responses from two coastal communities in the CSZ: Crescent City, CA and Coos Bay, OR. We applied multistage regression models to assess the effects of critical PADM variables. The results showed that three psychological variables (risk perception, perceived hazard knowledge, and evacuation mode efficacy) were associated with some demographic variables and experience variables. Evacuation intention and evacuation mode choice are associated with those psychological variables but not with demographic variables. Contrary to previous studies, location and experience had no direct impact on evacuation intention or mode choice. We also analyzed expected evacuation mode compliance and the potential of using micro-mobility during tsunami response. This study provides empirical evidence of tsunami preparedness and intentions to support interdisciplinary evacuation modeling, tsunami hazard education, community disaster preparedness, and resilience plans.
Keywords
False Discovery Rate; American-samoa; Earthquake; Washington; Behavior; Oregon; Wellington; Responses; Disaster; Tsunami Evacuation; Cascadia Subduction Zone; Risk Perception
Lin, Brenda B.; Ossola, Alessandro; Alberti, Marina; Andersson, Erik; Bai, Xuemei; Dobbs, Cynnamon; Elmqvist, Thomas; Evans, Karl L.; Frantzeskaki, Niki; Fuller, Richard A.; Gaston, Kevin J.; Haase, Dagmar; Jim, Chi Yung; Konijnendijk, Cecil; Nagendra, Harini; Niemela, Jari; Mcphearson, Timon; Moomaw, William R.; Parnell, Susan; Pataki, Diane; Ripple, William J.; Tan, Puay Yok. (2021). Integrating Solutions to Adapt Cities for Climate Change. Lancet Planetary Health, 5(7), E479 – E486.
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Abstract
Record climate extremes are reducing urban liveability, compounding inequality, and threatening infrastructure. Adaptation measures that integrate technological, nature-based, and social solutions can provide multiple co-benefits to address complex socioecological issues in cities while increasing resilience to potential impacts. However, there remain many challenges to developing and implementing integrated solutions. In this Viewpoint, we consider the value of integrating across the three solution sets, the challenges and potential enablers for integrating solution sets, and present examples of challenges and adopted solutions in three cities with different urban contexts and climates (Freiburg, Germany; Durban, South Africa; and Singapore). We conclude with a discussion of research directions and provide a road map to identify the actions that enable successful implementation of integrated climate solutions. We highlight the need for more systematic research that targets enabling environments for integration; achieving integrated solutions in different contexts to avoid maladaptation; simultaneously improving liveability, sustainability, and equality; and replicating via transfer and scale-up of local solutions. Cities in systematically disadvantaged countries (sometimes referred to as the Global South) are central to future urban development and must be prioritised. Helping decision makers and communities understand the potential opportunities associated with integrated solutions for climate change will encourage urgent and deliberate strides towards adapting cities to the dynamic climate reality.
Keywords
Urban; Resilience; Energy; Water; Transformations; Sustainability; Opportunities; Challenges; Mitigation; Knowledge
Shtrepi, Louena; Echenagucia, Tomás Méndez; Badino, Elena; Astolfi, Arianna. (2021). A Performance-based Optimization Approach For Diffusive Surface Topology Design. Building Acoustics, 28(3), 231 – 247.
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Abstract
Different numerical techniques have been used in the last decades for the acoustic characterization and performance optimization of sound diffusive surfaces. However, these methods require very long calculation times and do not provide a rapid feedback. As a result, these methods can hardly be applied by designers at early stages of the design process, when successive design iterations are necessary from an aesthetic point of view. A suitable alternative could be the use of parametric modeling in combination with performance investigations during the design process of sound diffusive surfaces. To this aim, this study presents a design process for diffusive surfaces topology optimization based on the combination of parametric models and geometrical acoustic simulations. It aims to provide architects and designers with rapid visual feedback on acoustic performances at a preliminary stage of the design process. The method has been tested on different case studies, which have been modelled based on geometric guidelines for diffusive surface optimization. The sensitivity of the method showed that it could be a very useful tool for comparisons among surface design alternatives. Finally, the advantages and limitations of the integrated optimization in comparison with conventional optimizations are discussed.
Keywords
Acoustic Performance; Room Acoustics; Scattering; Coefficients; Accuracy; Field; Simulations; Diffusion; Surface Optimization; Performance-based Design
Choi, Kunhee; Bae, Junseo; Yin, Yangtian; Lee, Hyun Woo. (2021). Act(2): Time Cost Tradeoffs from Alternative Contracting Methods. Journal Of Management In Engineering, 37(1).
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Abstract
Incentive/disincentive (I/D) and cost-plus-time (A+B) are two of the most widely used alternative contracting methods (ACMs) for accelerating the construction of highway infrastructure improvement projects. However, little is known about the effects of trade-offs in terms of project schedule and cost performance. This study addresses this problem by creating and testing a stochastic decision support model called accelerated alternative contracting cost-time trade-off (ACT(2)). This model was developed by a second-order polynomial regression analysis and validated by the predicted error sum of square statistic and paired comparison tests. The results of a descriptive trend analysis based on a rich set of high-confidence project data show that I/D is effective at reducing project duration but results in higher cost compared to pure A+B and conventional methods. This cost-time trade-off effect was confirmed by the ACT(2) model, which determines the level of cost-time trade-off for different ACMs. This study will help state transportation agencies promote more effective application of ACMs by providing data-driven performance benchmarking results when evaluating competing acceleration strategies and techniques. (C) 2020 American Society of Civil Engineers.
Keywords
Highway; Construction; Model; Alternative Contracting Methods; Cost-plus-time; A Plus B; Incentive; Infrastructure Trend; Time-cost Trade-off
Lin, Lin; Chen, Xueming (Jimmy); Moudon, Anne Vernez. (2021). Measuring the Urban Forms of Shanghai’s City Center and Its New Districts: A Neighborhood-Level Comparative Analysis. Sustainability, 13(15).
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Abstract
Rapid urban expansion has radically transformed the city centers and the new districts of Chinese cities. Both areas have undergone unique redevelopment and development over the past decades, generating unique urban forms worthy of study. To date, few studies have investigated development patterns and land use intensities at the neighborhood level. The present study aims to fill the gap and compare the densities of different types of developments and the spatial compositions of different commercial uses at the neighborhood level. We captured the attributes of their built environment that support instrumental activities of daily living of 710 neighborhoods centered on the public elementary schools of the entire Shanghai municipality using application programming interfaces provided in Baidu Map services. The 200 m neighborhood provided the best fit to capture the variations of the built environment. Overall, city center neighborhoods had significantly higher residential densities and housed more daily routine destinations than their counterparts in the new districts. Unexpectedly, however, the total length of streets was considerably smaller in city-center neighborhoods, likely reflecting the prominence of the wide multilane vehicular roads surrounding large center city redevelopment projects. The findings point to convergence between the city center's urban forms and that of the new districts.
Keywords
Quantifying Spatiotemporal Patterns; Fast-food Restaurants; Instrumental Activities; Physical-activity; Chinese Cities; Land; Schools; Redevelopment; Expansion; Transformation; Built Environment; Planning; Neighborhood; Urban Form; Shanghai
Soltaninejad, Mostafa; Fardhosseini, Mohammad Sadra; Kim, Yong Woo. (2021). Safety Climate and Productivity Improvement of Construction Workplaces Through the 6S System: Mixed-Method Analysis of 5S and Safety Integration. International Journal Of Occupational Safety & Ergonomics, 28(3), 1811-1821.
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Abstract
The purpose of this study is to develop a framework for integrating essential safety practices (visualization, job safety analysis and plan-do-check-act) into 5S steps and validate it. First, 18 interviews with a snowball sample of construction workers, safety representatives, supervisors and site and project managers were conducted. A grounded theory method was utilized to code the interview data. The results revealed that the studied construction companies implement a systematic safety-based methodology to minimize construction work injuries. Second, to validate the proposed framework, a pre-test and post-test study was applied. The case and control groups (26 participants) answered a 6S questionnaire before the 6S system and 1 month after implementation. The results revealed that safety climate and productivity significantly increased for the case group but reduced for the control group during time.
Keywords
5s Method; 6s System; Grounded Theory; Lean Construction; Productivity; Safety Climate; Health; Management; Leadership; Culture; Impact
Colburn, Gregg. (2021). The Use of Markets in Housing Policy: A Comparative Analysis of Housing Subsidy Programs. Housing Studies, 36(1), 46 – 79.
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Abstract
Many countries use demand-side housing subsidies to support low-income households. Unlike public or social housing programs, demand-side subsidies require recipients to enter the private market to use their benefits. The focus of this study is the experiences of assisted households in the private housing market and the outcomes they achieve. Given the link between policy design and program outcomes and because all housing subsidy programs are not created equal, one might expect the experiences and outcomes of recipients to also vary. To examine this relationship, using data from national housing surveys, this study analyzes cross-national variation in housing support programs and compares the housing and neighbourhood outcomes of subsidized households in the US, the UK, and the Netherlands. The findings of this study highlight that market context and policy design are associated with housing outcomes. In particular, the strong tenant supports and favourable design of housing assistance in the Netherlands is associated with favourable outcomes for subsidized households. In the US and the UK, subsidized households, in general, underperform their unsubsidized peers. This article underscores the importance of institutional context and program design when public assistance programs require recipients to enter the private market to use a benefit.
Keywords
Housing; Housing Subsidies; Comparative Studies; United States; Great Britain; Netherlands; Comparative; Outcomes; Subsidized Housing; Subsidy; Choice Vouchers; Poverty Deconcentration; United-states; Tax Credit; Income; Neighborhoods; Opportunity; Future; Britain; Comparative Analysis; Subsidies; Households; Context; Housing Policy; Design; Subsidies (financial); Housing Market; Low Income Groups; Public Housing; Assistance Programmes; United Kingdom--uk; United States--us
Luo, Minghai; Qin, Sixian; Tan, Bo; Cai, Mingming; Yue, Yufeng; Xiong, Qiangqiang. (2021). Population Mobility and the Transmission Risk of the Covid-19 in Wuhan, China. Isprs International Journal Of Geo-information, 10(6).
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Abstract
At the beginning of 2020, a suddenly appearing novel coronavirus (COVID-19) rapidly spread around the world. The outbreak of the COVID-19 pandemic in China occurred during the Spring Festival when a large number of migrants traveled between cities, which greatly increased the infection risk of COVID-19 across the country. Financially supported by the Wuhan government, and based on cellphone signaling data from Unicom (a mobile phone carrier) and Baidu location-based data, this paper analyzed the effects that city dwellers, non-commuters, commuters, and people seeking medical services had on the transmission risk of COVID-19 in the early days of the pandemic in Wuhan. The paper also evaluated the effects of the city lockdown policy on the spread of the pandemic outside and inside Wuhan. The results show that although the daily business activities in the South China Seafood Wholesale Market and nearby commuters' travel behaviors concentrated in the Hankou area, a certain proportion of these people were distributed in the Wuchang and Hanyang areas. The areas with relatively high infection risks of COVID-19 were scattered across Wuhan during the early outbreak of the pandemic. The lockdown in Wuhan closed the passageways of external transport at the very beginning, largely decreasing migrant population and effectively preventing the spread of the pandemic to the outside. However, the Wuhan lockdown had little effect on preventing the spread of the pandemic within Wuhan at that time. During this period, a large amount of patients who went to hospitals for medical services were exposed to a high risk of cross-infection without precaution awareness. The pandemic kept dispersing in three towns until the improvement of the capacity of medical treatment, the management of closed communities, the national support to Wuhan, and the implementation of a series of emergency responses at the same time. The findings in this paper reveal the spatiotemporal features of the dispersal of infection risk of COVID-19 and the effects of the prevention and control measures during the early days of the pandemic. The findings were adopted by the Wuhan government to make corresponding policies and could also provide supports to the control of the pandemic in the other regions and countries.
Keywords
Covid-19; Covid-19 Pandemic; Sars-cov-2; Seafood Markets; Pandemics; Cell Phones; City Dwellers; Wuhan (china); Big Data; Novel Coronavirus; Population Mobility; Risk Analysis; Zika Virus; Diseases; Africa; Impact; Ebola; Spain; Passageways; Smartphones; Investigations; Disease Control; Emergency Response; Health Services; Viral Diseases; Policies; Outbreaks; Emergency Preparedness; Risk; Seafood; Coronaviruses; Medical Treatment; Transmission; Commuting; Dispersion; Dispersal; Infections; Cross-infection; Epidemics; Health Risks; Disease Transmission; China