Sun, Feiyang; Chen, Peng; Jiao, Junfeng. (2018). Promoting Public Bike-Sharing: A Lesson from the Unsuccessful Pronto System. Transportation Research: Part D, 63, 533 – 547.
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Abstract
In 2014, Seattle implemented its own bike-sharing system, Pronto. However, the system ultimately ceased operation three years later on March 17th, 2017. To learn from this failure, this paper seeks to understand factors that encourage, or discourage, bike-sharing trip generation and attraction at the station level. This paper investigates the effects of land use, roadway design, elevation, bus trips, weather, and temporal factors on three-hour long bike pickups and returns at each docking station. To address temporal autocorrelations and the nonlinear seasonality, the paper implements a generalized additive mixed model (GAMM) that incorporates the joint effects of a time metric and time-varying variables. The paper estimates models on total counts of pickups and returns, as well as pickups categorized by user types and by location. The results clarify that effects of hilly terrain and the rainy weather, two commonly perceived contributors to the failure. Additionally, results suggest that users in the University District, presumably mostly university students, tend to use shared bikes in neighborhoods with a higher household density and a higher percentage of residential land use, and make bike-sharing trips regardless workdays or non-workdays. The paper also contributes to the discussion on the relationship between public transportation service and bike-sharing. In general, users tend to use bike-sharing more at stations that have more scheduled bus trips nearby. However, some bike-sharing users may shift to bus services during peak hours and rainy weather. Several strategies are proposed accordingly to increase bike ridership in the future.
Keywords
Bicycle Sharing Programs; Urban Transportation; Transportation & The Environment; Land Use Planning; Time-varying Systems; Bike-sharing; Built Environment; Generalized Additive Mixed Model; Pronto; Temporal Factors; Built Environment Factors; Bicycle; Impact; Transportation; Walking; Usage
Habibnezhad, Mahmoud; Puckett, Jay; Jebelli, Houtan; Karji, Ali; Fardhosseini, Mohammad Sadra; Asadi, Somayeh. (2020). Neurophysiological Testing for Assessing Construction Workers’ Task Performance at Virtual Height. Automation In Construction, 113.
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Abstract
Falling from heights is the primary cause of death and injuries at construction sites. As loss of balance has a fundamental effect on falling, it is important to understand postural regulation behavior during construction tasks at heights, especially those that require precise focus in an upright standing position (therefore, a dual-task demand on focus). Previous studies examined body sway during a quiet stance and dual tasks to understand latent factors affecting postural balance. Despite the success of these studies in discovering underlying factors, they lack a comprehensive analysis of a task's simultaneous cognitive load, postural sway, and visual depth. To address this limitation, this paper aims to examine construction workers' postural stability and task performance during the execution of visual construction tasks while standing upright on elevated platforms. To that end, two non-intrusive neurophysiological tests, a hand-steadiness task (HST) and a pursuit task (PT), were developed for construction tasks in a virtual environment (VE) as performance-based means to assess the cognitive function of workers at height. Workers' postural stability was measured by recording the mapped position of the Center of Pressure (COP) of the body on a posturography force plate, and the postural sway metrics subsequently calculated. A laboratory experiment was designed to collect postural and task performance data from 18 subjects performing the two batteries of tests in the virtual environment. The results demonstrated a significant decrease in the Root-Mean Square (RMS) of COP along the anterior-posterior axis during the Randomized Pursuit Task (RPT) and maximum body sway of the center of pressure (COP) in the mediolateral direction during both tests. Also, subjects exposed to high elevation predominately exhibit higher accuracy for RPT (P-value = 0.02) and lower accuracy for HST (P-value = 0.05). The results show that the combination of elevation-related visual depth and low-complexity dual tasks impairs task performance due to the elevation-induced visual perturbations and anxiety-driven motor responses. On the other hand, in the absence of visual depth at height, high task complexity surprisingly improves the pursuit tracking performance. As expected, during both tasks, alterations in postural control were manifested in the form of a body sway decrement as a compensatory postural strategy for accomplishing tasks at high elevation.
Keywords
Task Performance; Construction Workers; Test Design; Cognitive Load; Standing Position; Sitting Position; Neurophysiological Test; Postural Stability; Virtual Reality; Workers' Safety At Height; Fall-risk; Reaction-time; Fear; Real; Acrophobia; Balance; Safety
Kerfeld, Cheryl I.; Hurvitz, Philip M.; Bjornson, Kristie F. (2021). Physical Activity Measurement in Children Who Use Mobility Assistive Devices: Accelerometry and Global Positioning System. Pediatric Physical Therapy, 33(2), 92 – 99.
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Abstract
Purpose: To explore the usefulness of combining accelerometry, global positioning systems, and geographic information systems, to describe the time spent in different locations and physical activity (PA) duration/count levels by location for 4 children with cerebral palsy (CP) who use assistive devices (AD). Methods: A descriptive multiple-case study. Results: Combining the 3 instruments was useful in describing and differentiating duration by location, and amount and location of PA across differing functional levels and AD. For example, the child classified with a Gross Motor Function Classification System (GMFCS) level II exhibited large amounts of PA in community settings. In contrast, the child classified with a GMFCS level V had small amounts of PA and spent most measured time at home. Conclusions: Combined accelerometry, global positioning system, and geographic information system have potential to capture time spent and amount/intensity of PA relative to locations within daily environments for children with CP who use AD.
Keywords
Cerebral-palsy; Objective Measures; Fitness; Youth; Disabilities; Adolescents; Exercise; Adults; Accelerometer; Cerebral Palsy; Environment; Global Positioning System; Mobility Assistive Devices; Physical Activity
Inanici, Mehlika. (2010). Evalution of High Dynamic Range Image-Based Sky Models in Lighting Simulation. Leukos, 7(2), 69 – 84.
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Abstract
High Dynamic Range (HDR) Photography is used to capture 180 degrees images of the sky dome and provide data for image-based lighting in lieu of CIE sky models.
El-Anwar, Omar; Chen, Lei. (2014). Maximizing the Computational Efficiency of Temporary Housing Decision Support Following Disasters. Journal Of Computing In Civil Engineering, 28(1), 113 – 123.
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Abstract
Postdisaster temporary housing has long been a challenging problem because of its interlinked socioeconomic, political, and financial dimensions. A significant need for automated decision support was obvious to address this problem. Previous research achieved considerable advancements in developing optimization models that can quantify and optimize the impacts of temporary housing decisions on the socioeconomic welfare of displaced families and total public expenditures on temporary housing as well as other objectives. However, the computational complexity of these models hindered its practical use and adoption by emergency planners. This article analyzes the computational efficiency of the current implementation of the most advanced socioeconomic formulation of the temporary housing problem, which uses integer programming. Moreover, it presents the development of a customized variant of the Hungarian algorithm that has a superior computational performance while maintaining the highest quality of solutions. An application example is presented to demonstrate the unique capabilities of the new algorithm in solving large-scale problems.
Keywords
Decision Support Systems; Emergency Management; Integer Programming; Computational Efficiency; Temporary Housing Decision Support Following Disasters; Financial Dimensions; Political Dimensions; Socioeconomic Dimensions; Socioeconomic Welfare; Emergency Planners; Socioeconomic Formulation; Hungarian Algorithm; Multiobjective Optimization; Maeviz-hazturk; Housing; Computation; Disasters; Temporary Structures; Temporary Housing; Optimization; Disaster Management
Anderson, Anne; Dossick, Carrie Sturts; Iorio, Josh; Taylor, John E. (2017). The Impact of Avatars, Social Norms and Copresence on the Collaboration Effectiveness of AEC Virtual Teams. Journal Of Information Technology In Construction, 22, 287 – 304.
Abstract
A growing number of architecture, engineering, and construction (AEC) firms are outsourcing complex design and construction work to international vendors. Due to the significant geographic distances that can separate project team members in global design networks, much of this work is executed in virtual teams, defined as teams composed of geographically separated members who collaborate to accomplish organizational tasks mediated by technology. The challenges of working in geographically distributed networks have prompted the development of alternative, virtual workspaces. Questions remain on how these virtual workspaces support or hinder collaborative work. People are social beings that rely on body language and other non-verbal cues to communicate. What happens to team formation and collaborative effectiveness when non-verbal cues are mediated through avatar actions? In this paper, qualitative ethnographic data collected over four years from studies conducted in a 3D virtual world are used to examine collaboration effectiveness of global virtual engineering project teams. We found that avatar movement and position was effective at communicating nonverbal information, even when done so unintentionally. Avatar actions that map to established social norms in the physical world results in more efficient communication. Collaboration was also enhanced when gesture bubbles were used for backchannel communication and when text chat was used to avoid interrupting voice communication. We found collaboration was hindered when the learning curve was too steep for participants to adapt to tool use or avatar actions in the environment. These findings have important implications for the future of collaboration in virtual environments, particularly in the AEC industry where 3D models can be imported into the virtual environment and explored synchronously by a project team.
Keywords
Architectural Design; Human Resource Management; International Trade; Bim Coordination; Collaboration Technology; Distributed Teams; Social Norm; Virtual Worlds; Communication; Design; Technology; Dimensions; Teamwork; Behavior; Collaboration Technologies; Social Norms
Taylor, John E.; Alin, Pauli; Anderson, Anne; Çomu, Semra; Dossick, Carrie Sturts; Hartmann, Timo; Iorio, Josh; Mahalingam, Ashwin; Mohammadi, Neda. (2018). Cybergrid: A Virtual Workspace for Architecture, Engineering, and Construction. Transforming Engineering Education: Innovative, Computer-mediated Learning Technologies, 291-321.
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Abstract
Projects in the architecture, engineering and construction (AEC) industry frequently involve a large number of firms that increasingly span national boundaries. National boundary spanning by AEC firms engaged in complex, interdependent work introduces coordination challenges because stakeholders may not share the same language, culture or work practices. These types of firms have begun to explore the use of technologies that can meaningfully create productive work connections between the distributed participants 47 and help improve work coordination and execution. In this chapter, we describe the CyberGRID (Cyber-enabled Global Research Infrastructure for Design); a virtual workspace designed to support geographically distributed AEC work coordination and execution. The CyberGRID was created as a research tool to both enable and study virtual AEC teamwork. We summarize findings from multiple experiments over the jive year history of CyberGRID research and development. These findings help to improve our understanding of interactional dynamics among virtual teams in complex sociotechnical systems like the CyberGRID. We then discuss the challenges faced in developing the CyberGRID and in achieving widespread adoption of such tools in the industry. We close the chapter with a discussion of future research opportunities to develop improved sociotechnical systems to better support the execution of AEC projects. Our goal with this chapter is to argue that sociotechnical systems like the CyberGRID can fundamentally and positively transform the interactional dynamics of AEC project stakeholders to create more efficient global virtual work practices.
Keywords
Civil Engineering Computing; Construction Industry; Data Visualisation; Groupware; Project Management; Team Working; Virtual Reality; Cybergrid; Virtual Workspace; Construction; Engineering; National Boundaries; National Boundary Spanning; Aec Firms; Complex Work; Interdependent Work; Coordination Challenges; Culture; Productive Work Connections; Chapter; Global Research Infrastructure; Geographically Distributed Aec Work Coordination; Research Tool; Virtual Aec Teamwork; Virtual Teams; Complex Sociotechnical Systems; Future Research Opportunities; Improved Sociotechnical Systems; Aec Projects; Aec Project Stakeholders; Efficient Global Virtual Work Practices
Kim, Taehoon; Kim, Yong-Woo; Cho, Hunhee. (2020). Dynamic Production Scheduling Model Under Due Date Uncertainty in Precast Concrete Construction. Journal Of Cleaner Production, 257.
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Abstract
Precast concrete structures (PCs) are widely used in the construction industry to reduce project delivery times and improve quality. On-time delivery of PCs is critical for successful project completion because the processes involving precast concrete are the critical paths in most cases. However, existing models for scheduling PC production are not adequate for use in dynamic environments where construction projects have uncertain construction schedules because of various reasons such as poor labor productivity, inadequate equipment, and poor weather. This research proposes a dynamic model for PC production scheduling by adopting a discrete-time simulation method to respond to due date changes in real time and by using a new dispatching rule that considers the uncertainty of the due dates to minimize tardiness. The model is validated by simulation experiments based on various scenarios with different levels of tightness and due date uncertainty. The results of this research will contribute to construction project productivity with a reliable and economic precast concrete supply chain. (C) 2020 Elsevier Ltd. All rights reserved.
Keywords
Multiple Production; Demand Variability; Supply Chain; Shop; Management; Minimize; Lines; Precast Concrete Production; Dynamic Simulation; Uncertainty; Production Scheduling; Dispatching Rule
Nemati, Kamran M.; Uhlmeyer, Jeff S. (2021). Accelerated Construction of Urban Intersections with Portland Cement Concrete Pavement (PCCP). Case Studies In Construction Materials, 14.
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Abstract
The frequent maintenance required on asphalt concrete (AC) pavement sections has made reconstruction with portland cement concrete pavement (PCCP) a feasible alternative. However, many constructability issues need to be addressed in order to realize the full potential of this alternative. Accelerated paving encompasses three classes of activities: methods to accelerate the rate of strength gain, methods to minimize the construction time, and traffic control strategies to minimize user delay. In this paper a case study will be presented in which an AC intersection was reconstructed with portland cement concrete pavement. The entire reconstruction of the intersection, including demolition of the AC pavement and its replacement with PCCP, took place over a period of three days, starting on Thursday evening and opening the intersection to the traffic on Sunday afternoon. This paper documents this effort in order to provide practitioners additional options for rapid reconstruction of urban intersections and includes documentation of the construction process, traffic management strategies, and an analysis of the costs. The results of this investigation can be used to educate pavement construction professionals and the academic community on the use of PCCP for accelerated reconstruction of major urban intersections with minimal user and traffic disruption, using innovative construction techniques and traffic management optimization principles. This investigation produced valuable information to demonstrate that concrete pavements can be constructed efficiently and quickly. (C) 2021 The Authors. Published by Elsevier Ltd.
Keywords
Concrete; Accelerated Construction; Pavement; Portland Cement Concrete Pavement; Maturity Method
Neff, Gina; Fiore-Silfvast, Brittany; Dossick, Carrie Sturts. (2010). A Case Study of the Failure of Digital Communication to Cross Knowledge Boundaries in Virtual Construction. Information Communication & Society, 13(4), 556 – 573.
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Abstract
When can digital artefacts serve to bridge knowledge barriers across epistemic communities? There have been many studies of the roles new information and communication technologies play within organizations. In our study, we compare digital and non-digital methods of inter-organizational collaboration. Based on ethnographic fieldwork on three construction projects and interviews with 65 architects, engineers, and builders across the USA, we find that IT tools designed to increase collaboration in this setting instead solidify and make explicit organizational and cultural differences between project participants. Our study suggests that deeply embedded disciplinary thinking is not easily overcome by digital representations of knowledge and that collaboration may be hindered through the exposure of previously implicit distinctions among the team members' skills and organizational status. The tool that we study, building information modelling, reflects and amplifies disciplinary representations of the building by architects, engineers, and builders instead of supporting increased collaboration among them. We argue that people sometimes have a difficult time overcoming the lack of interpretive flexibility in digital coordinating tools, even when those tools are built to encourage interdisciplinary collaboration.
Keywords
Digital Communications; Data Transmission Systems; Communication & Technology; Digital Electronics; System Analysis; Building Information Modelling; Collaboration; Qualitative Methods; Teams; Civil Engineering Computing; Digital Communication; Groupware; Knowledge Representation; Organisational Aspects; Virtual Reality; Case Study; Virtual Construction; Knowledge Barriers; Epistemic Community; Interorganizational Collaboration; Ethnographic Fieldwork; Interpretive Flexibility; Digital Coordinating Tool; Digital Collaboration; Technology; Objects; Design; Representations; Organizations