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
Habibnezhad, M.; Puckett, J.; Fardhosseini, M.S.; Pratama, L.A. (2019). A Mixed VR and Physical Framework to Evaluate Impacts of Virtual Legs and Elevated Narrow Working Space on Construction Workers Gait Pattern. Arxiv, 7 pp.
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Abstract
It is difficult to conduct training and evaluate workers' postural performance by using the actual job site environment due to safety concerns. Virtual reality (VR) provides an alternative to create immersive working environments without significant safety concerns. Working on elevated surfaces is a dangerous scenario, which may lead to gait and postural instability and, consequently, a serious fall. Previous studies showed that VR is a promising tool for measuring the impact of height on the postural sway. However, most of these studies used the treadmill as the walking locomotion apparatus in a virtual environment (VE). This paper was focused on natural walking locomotion to reduce the inherent postural perturbations of VR devices. To investigate the impact of virtual height on gait characteristics and keep the level of realism and feeling of presence at their highest, we enhanced the first-person-character model with "virtual legs". Afterward, we investigated its effect on the gait parameters of the participants with and without the presence of height. To that end, twelve healthy adults were asked to walk on a virtual loop path once at the ground level and once at the 17th floor of an unfinished structure. By quantitatively comparing the participants' gait pattern results, we observed a decrease in the stride length and increase in the gait duration of the participants exposed to height. At the ground level, the use of the enhanced model reduced participants' average stride length and height. The results of this study help us understand users' behaviors when they were exposed to elevated surfaces and establish a firm ground for gait stability analysis for the future height-related VR studies. We expect this developed VR platform can generate reliable results of VR application in more construction safety studies.
Keywords
Civil Engineering Computing; Construction Industry; Gait Analysis; Medical Computing; Occupational Safety; Virtual Reality; Construction Safety Studies; Mixed Vr; Virtual Legs; Construction Workers Gait Pattern; Immersive Working Environments; Postural Instability; Serious Fall; Postural Sway; Walking Locomotion Apparatus; Natural Walking Locomotion; Inherent Postural Perturbations; Vr Devices; Virtual Height; First-person-character Model; Gait Parameters; Virtual Loop Path; Stride Length; Gait Duration; Gait Stability Analysis; Safety Concerns; Vr Platform; Height-related Vr Studies
Parsaee, Mojtaba; Demers, Claude M. H.; Lalonde, Jean-francois; Potvin, Andre; Inanici, Mehlika; Hebert, Marc. (2020). Human-Centric Lighting Performance of Shading Panels in Architecture: A Benchmarking Study with Lab Scale Physical Models Under Real Skies. Solar Energy, 204, 354 – 368.
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Abstract
This study investigates shading panels' (SPs) impacts on daylighting features in a lab scale model in terms of parameters representing potential human eyes' biological responses identified as image forming (IF) and non-image forming (NIF). IF responses enable vision and NIF responses regulate internal body clocks known as circadian clocks. Human-centric lighting evaluates photopic units, representing IF responses, and melanopic units representing NIF responses, combined with correlated color temperature (CCT) of light for potential biological effects. SPs' impacts on such parameters of daylighting have not yet been studied. Previous research mostly studied panels' impacts on visual comfort and glare related to IF responses. This research explores the impact of SPs' color, reflectance, orientation, and openness on photopic and melanopic units and CCT of daylighting inside a 1:50 physical scale model of a space. Approximately 40 prototypes of SPs were evaluated. An experimental setup was designed under outdoor daylighting conditions to capture high dynamic range (HDR) images inside the model. HDR images were post processed to calculate and render the distribution of photopic and melanopic units, melanopic/photopic (M/P) ratios and CCTs in the captured viewpoint of the model. Results reveal the behavior of SPs' color, reflectance, orientation, and openness in modifying daylighting parameters related to biological responses. Bluish panels, in particular, increase daylighting melanopic units and CCTs whereas reddish panels increase photopic units and reduce CCTs. The research results were discussed to provide an outline for future developments of panels to adapt daylighting to occupants' IF and NIF responses.
Keywords
Models & Modelmaking; Shades & Shadows; Daylighting; Color Temperature; Benchmarking (management); Ecological Houses; Eye Tracking; Circadian Rhythms; Adaptive Design; Healthy Lighting; High Performance Façade; Photobiology; Responsive Building; Design; Sensitivity; Illuminance; Systems; Spaces; Impact; Glare; High Performance Facade; Reflectance; Scale Models; Biological Effects; Human Performance; Prototypes; Parameter Modification; Lighting; Shading; Eye (anatomy); Color; Parameter Identification; Light Effects; Panels; Mathematical Models; Images; Biological Clocks; Orientation
Zou, Tianqi; Aemmer, Zack; Mackenzie, Don; Laberteaux, Ken. (2022). A Framework for Estimating Commute Accessibility and Adoption of Ridehailing Services Under Functional Improvements from Vehicle Automation. Journal Of Transport Geography, 102.
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Abstract
This paper develops an analytical framework to estimate commute accessibility and adoption of various ridehailing service concepts across the US by synthesizing individual commute trips using national Longitudinal Employer-Household Dynamics Origin-Destination Employment Statistics (LODES) data. Focusing on potential improvements in cost and time that could be enabled by vehicle automation, we use this modeling framework to simulate a lower-price autonomous service (e.g., 50% or 75% lower) with variable wait times and implementation levels (solo, pooled, and first/last mile transit connections services, alone or in combination) to determine how they might affect adoption rates. These results are compared across metrics of accessibility and trip density, as well as socioeconomic factors such as household income. We find - unsurprisingly - that major cities (e.g. New York, Los Angeles, and Chicago) support the highest adoption rates for ridehailing services. Decreases in price tend to increase market share and accessibility. The effect of a decrease in price is more drastic for lower income groups. The proposed method for synthesizing trips using the LODES contributes to current travel demand forecasting methods and the proposed analytic framework can be flexibly implemented with any other mode choice model, extended to non-commute trips, or applied to different levels of geographic aggregation.
Keywords
Choice Of Transportation; Demand Forecasting; Poor People; Adoption; Price Cutting; Metropolis; Employment Statistics; Los Angeles (calif.); New York (state); Chicago (ill.); Accessibility; Autonomous Vehicles; New Mobility Services; Ridehailing; Travel Demand; Preferences
Armbruster, Ginger; Endicott-Popovsky, Barbara; Whittington, Jan. (2013). Threats to Municipal Information Systems Posed by Aging Infrastructure. International Journal Of Critical Infrastructure Protection, 6(3-4), 123 – 131.
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Abstract
State and local governments across the United States are leveraging the Internet and associated technologies to dramatically change the way they offer public services. While they are motivated to capture efficiencies, the public entities increasingly rely on information systems that are dependent on energy and related civil structures. This reliance is incongruous with the widespread awareness of aging infrastructure - decaying for lack of investment - in cities across the United States. Important questions that come up in this environment of persistent expansion of the use of digital assets are the following: What threat does aging infrastructure pose to governmental reliance on computing infrastructures? How are local governments responding to this threat? Are the solutions posed appropriate to the problem, or do they pose new and different threats? This paper uses a case involving the disruption of a local government data center due to the failure of an electrical bus to illustrate how the threats of aging infrastructure grow, quietly and steadily, into emergencies, on par with the catastrophic events encountered in the context of critical infrastructure protection. The decisions precipitating the disruption are routine, borne of circumstances shared by agencies that are pressed to maintain services with scarce resources. Patterns of capital investment and management explain the emergence of crises in routine operations. If, as in the case described in this paper, deferred maintenance motivates public agents to explore private cloud services, then governments may solve several problems, but may also be exposed to new risks as they enter into arrangements from which they are unable to exit. (C) 2013 Elsevier B.V. All rights reserved.
Keywords
Aging Infrastructure; Municipal Data Center; Capital Improvement; Interdependence
Abdirad, Hamid; Dossick, Carrie S. (2016). BIM Curriculum Design in Architecture, Engineering, and Construction Education: A Systematic Review. Journal Of Information Technology In Construction, 21, 250 – 271.
Abstract
In the past several years, Building Information Modeling (BIM) adoption has grown significantly in the architecture, engineering, and construction (AEC) industry. In response to this trend, the industry and academia realized that BIM education in university curricula is an important requirement for satisfying educational demands of the industry, and a notable body of research has reported strategies AEC programs implemented to incorporate BIM in their curricula. However, no study has comprehensively reviewed and synthesized the research on sfrategies adopted by educators. To bridge this gap in the literature, this paper presents a systematic review of research on BIM curriculum design in AEC education. The authors report on the trends of research on BIM curriculum design (e.g. methods, timelines, and contexts) as well as a synthesis of implemented pedagogical strategies with detailed discussions on their implications and effectiveness across different studies and contexts. These strategies address a variety of important pedagogical issues such as enrolment of students, optional or required BIM use, important competencies and skills, tutoring methods, industry engagement, designing assignments, and assessment methods and criteria. This synthesis shows that designing pedagogical sfrategies for BIM education is complex and challenging, and AEC programs need to make trade-offs between advantages and disadvantages associated with these strategies. The results also highlight the need for more diverse research designs and settings to bridge the gaps identified in BIM curriculum research to date. Finally, the authors present a literature-based framework of BIM curriculum design sfrategies as well as a set of recommendations that can be used BIM educators and researchers as a guide for designing or assessing their BIM curricula in future research.
Keywords
Bridges; Curricula; Economic And Social Effects; Education; Information Theory; Personnel Training; Reviews; Students; Architecture; Engineering; And Constructions; Building Information Model; Bim; Curriculum Designs; Pedagogical Issues; Pedagogical Strategies; Research Designs; Systematic Review; University Curricula; Industry; Management; Building Information Modeling; Training; Curriculum; Review
Song, Jiule; Migliaccio, Giovanni C.; Wang, Guangbin; Lu, Hao. (2017). Exploring the Influence of System Quality, Information Quality, and External Service on BIM User Satisfaction. Journal Of Management In Engineering, 33(6).
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Abstract
Over the past decade, architecture, engineering and construction (AEC) companies around the world implemented building information modeling (BIM) to enhance their firms' competitiveness and readjust their business processes. Although substantial efforts have been made to implement BIM, previous research highlighted that implementation of BIM tools has not always resulted in satisfaction by users. Grounded in the literature on information systems and enterprise resource planning user satisfaction, this study tries to evaluate the success of BIM in terms of user satisfaction while controlling for the mediating effect of top-management support. The effects of four factors (i.e., system quality, information quality, external service, and top-management support) on BIM user satisfaction in AEC industries were examined through a survey of BIM users from China. Survey responses were analyzed with the partial least-squares method. The major contribution of this work lies in the findings that information quality, external service, and top-management support have a significant influence on BIM user satisfaction, and system quality did not have a significant influence on BIM user satisfaction. Moreover, top-management support acts as a mediating factor between external service and BIM user satisfaction. (C) 2017 American Society of Civil Engineers.
Keywords
Computing Satisfaction; Perceived Usefulness; Erp Systems; Success; Model; Performance; Technology; Acceptance; Tool; Determinants; Bim User Satisfaction; System Quality; Information Quality; External Services; Top-management Support
Jung, B.; Inanici, M. (2019). Measuring Circadian Lighting through High Dynamic Range Photography. Lighting Research & Technology, 51(5), 742 – 763.
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Abstract
The human ocular system functions in a dual manner. While the most well-known function is to facilitate vision, a growing body of research demonstrates its role in resetting the internal body clock to synchronize with the 24-hour daily cycle. Most research on circadian rhythms is performed in controlled laboratory environments. Little is known about the variability of circadian light within the built and natural environments. Currently, very few specialized devices measure the circadian light, and they are not accessible to many researchers and practitioners. In this paper, tristimulus colour calibration procedures for high dynamic range photography are developed to measure circadian lighting. Camera colour accuracy is evaluated through CIE trichromatic (XYZ) measurements; and the results demonstrate a strong linear relationship between the camera recordings and a scientific-grade colorimeter. Therefore, it is possible to correct for the colour aberrations and use high dynamic range photographs to measure both photopic and circadian lighting values. Spectrophotometric measurements are collected to validate the methodology. Results demonstrate that measurements from high dynamic range photographs can correspond to the physical quantity of circadian luminance with reasonable precision and repeatability. Circadian data collected in built environments can be utilized to study the impact of design decisions on human circadian entrainment and to create guidelines and metrics for designing circadian friendly environments.
Keywords
Physical Constants; Medical Photography; Photography; Built Environment; Morningness-eveningness Questionnaire; Statistical Reliability; Circadian Rhythms; Action Spectrum; Ganglion-cells; Bright Light; Exposure; Sensitivity; Framework; Daylight; Daytime; Model; Rod
Zou, Tianqi; Khaloei, Moein; Mackenzie, Don. (2020). Effects of Charging Infrastructure Characteristics on Electric Vehicle Preferences of New and Used Car Buyers in the United States. Transportation Research Record, 2674(12), 165 – 175.
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Abstract
The used car market is a critical element for the mass adoption of electric vehicles (EVs). However, most previous studies on EV adoption have focused only on new car markets. This article examines and compares the effects of charging infrastructure characteristics on the preferences for EVs among both new and used car buyers. This study is based on an online stated preference choice experiment among private car owners in the U.S., and the results of comparable binomial logistic models show that new and used car buyers generally share similar patterns in preferences for EVs, with exceptions for sensitivity toward fast charging time, and home charging solutions. Respondents' stated willingness to adopt an EV increases considerably with improvements in driving range, and the effects on new and used car buyers are similar. The study also finds that better availability of charging infrastructure largely increases preference for EVs. The results further reveal that slow and fast charging have complementary effects on encouraging EV adoption as the combination of public slow and fast charging can compensate for the unavailability of home charging.
Roca, Pere; Liew, Andrew; Block, Philippe; Lopez, David Lopez; Echenagucia, Tomás Méndez; Van Mele, Tom. (2022). A Three-Dimensional Approach to the Extended Limit Analysis of Reinforced Masonry. Structures, 35, 1062 – 1077.
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Abstract
The Extended Limit Analysis of Reinforced Masonry (ELARM) is a simple and user-friendly method for the design and structural analysis of singly-curved, reinforced tile vaults [1]. It is based on limit analysis but takes into account the reinforcement's contribution to the composite cross-section's bending capacity.& nbsp;A three-dimensional approach to ELARM is presented in this paper. The theoretical framework to understand the implications and limitations of extending ELARM to fully 3D structures is described, together with the strategies to carry out the leap from 2D to 3D. This extension is a lower-bound approach for the design of reinforced masonry, reinforced concrete and concrete-masonry composite shells and the assessment of their strength and stability against external loading.& nbsp;The new, extended method is implemented computationally to speed up the iterative processes, provide quick structural feedback, offer immediate results and allow for user-interactive form-finding and optimisation procedures. Different applications of the developed tool are described through the presentation of examples, including reinforcement optimisation, a form-finding process and a case with a shape beyond funicular geometry.
Keywords
Tile Vault; Masonry; Reinforced Brick; Formwork; Concrete Shells; Limit Analysis; Thrust Network Analysis; Extended Limit Analysis Of Reinforced Masonry; Tile Vaults