Sprague, Tyler S. (2013). Beauty, Versatility, Practicality: The Rise of Hyperbolic Paraboloids in Post-War America (1950-1962). Construction History-international Journal Of The Construction History Society, 28(1), 165 – 184.
Abstract
The hyperbolic paraboloid was relatively unknown in the United States prior to 1950 but, by 1962, it had gained widespread recognition and acceptance among practising and academic architects, structural engineers and builders. Aligning with the architectural trends and structural capabilities of the post-war era, hyperbolic paraboloids were used to construct everything from churches to warehouses and residences to gas stations. They could be constructed in many different ways and built with different materials including reinforced concrete, plywood and aluminium. The hyperbolic paraboloid became synonymous with innovation and experimentation in construction technology. This paper reviews the people and buildings that influenced the rise in popularity of the hyperbolic paraboloid forms, traces different construction practices used to build them in the post-war Americas, and tracks their emergence as a built form that characterised the American post-war era.
Keywords
Hyperbolic Paraboloid; Construction Innovation; Aluminium; Plywood; Concrete Construction; Formwork; Usa; 1950s
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
Saelens, Brian E.; Moudon, Anne Vernez; Kang, Bumjoon; Hurvitz, Philip M.; Zhou, Chuan. (2014). Relation between Higher Physical Activity and Public Transit Use. American Journal Of Public Health, 104(5), 854 – 859.
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Abstract
Objectives. We isolated physical activity attributable to transit use to examine issues of substitution between types of physical activity and potential confounding of transit-related walking with other walking. Methods. Physical activity and transit use data were collected in 2008 to 2009 from 693 Travel Assessment and Community study participants from King County, Washington, equipped with an accelerometer, a portable Global Positioning System, and a 7-day travel log. Physical activity was classified into transit-and non-transit-related walking and nonwalking time. Analyses compared physical activity by type between transit users and nonusers, between less and more frequent transit users, and between transit and nontransit days for transit users. Results. Transit users had more daily overall physical activity and more total walking than did nontransit users but did not differ on either non-transit-related walking or nonwalking physical activity. Most frequent transit users had more walking time than least frequent transit users. Higher physical activity levels for transit users were observed only on transit days, with 14.6 minutes (12.4 minutes when adjusted for demographics) of daily physical activity directly linked with transit use. Conclusions. Because transit use was directly related to higher physical activity, future research should examine whether substantive increases in transit access and use lead to more physical activity and related health improvements.
Keywords
Transportation; Analysis Of Covariance; Analysis Of Variance; Chi-squared Test; Comparative Studies; Confidence Intervals; Geographic Information Systems; Research Funding; Statistics; Walking; Data Analysis; Accelerometry; Cross-sectional Method; Exercise Intensity; Physical Activity; Diary (literary Form); Descriptive Statistics; Washington (state); Work; Car; Impact
Estiri, Hossein; Krause, Andy; Heris, Mehdi P. (2015). Phasic Metropolitan Settlers: A Phase-Based Model for the Distribution of Households in US Metropolitan Regions. Urban Geography, 36(5), 777 – 794.
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Abstract
In this article, we develop a model for explaining spatial patterns in the distribution of households across metropolitan regions in the United States. First, we use housing consumption and residential mobility theories to construct a hypothetical probability distribution function for the consumption of housing services across three phases of household life span. We then hypothesize a second probability distribution function for the offering of housing services based on the distance from city center(s) at the metropolitan scale. Intersecting the two hypothetical probability functions, we develop a phase-based model for the distribution of households in US metropolitan regions. We argue that phase one households (young adults) are more likely to reside in central city locations, whereas phase two and three households are more likely to select suburban locations, due to their respective housing consumption behaviors. We provide empirical validation of our theoretical model with the data from the 2010 US Census for 35 large metropolitan regions.
Keywords
Residential-mobility; Life-course; Housing Consumption; Family; Satisfaction; Migration; Geography; Context; Age; Distribution Patterns; Us Metropolitan Regions; Household
Abramson, Daniel Benjamin. (2016). Periurbanization and the Politics of Development-as-City-Building in China. Cities, 53, 156 – 162.
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Abstract
China stands out among recently urbanized societies for the planned physicality of its rural-urban transformation the extensive marshaling of labor, capital and material resources to remake its cities and to transform rural land and communities into new, formal urban space. In China, the rural and the urban are distinguished in deeply dichotomous institutions of government, and peri-urbanization, defined as the disorderly spaces, processes and conditions of becoming urban, would appear to be a temporary stage of transition between an old rural socio-spatial order to a new urban socio-spatial order. The actual contested politics of development as-urbanization suggests otherwise, however, both on a national scale and on a community scale. The definition of development itself is at stake, and emerges unpredictably from peri-urban experience. A view of periurbanization as a process of socio-ecological adaptation is better suited to societies that have evolved in long settled, densely populated anthropogenic agrarian landscapes. (C) 2015 Published by Elsevier Ltd.
Keywords
Urban-growth; Chengdu; Urbanization; Adaptation; Resilience; Alternative Development; Socialist New Countryside Construction; New Rural Reconstruction
Fantilli, Alessandro P.; Nemati, Kamran M.; Chiaia, Bernardino. (2016). Efficiency Index for Fiber-Reinforced Concrete Lining at Ultimate Limit State. Sustainable And Resilient Infrastructure, 1(1-2), 84 – 91.
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Abstract
The fiber contribution to the ultimate limit state capacity of precast and cast-in situ tunnel linings is analytically investigated. By means of a numerical model, capable of computing the interaction curves of reinforced concrete cross sections subjected to combined compressive and bending actions, the mechanical performances of plain and fiber-reinforced concrete are compared. As a result, a new index is introduced to quantify the effectiveness of fiber addition. The higher the efficiency index, the higher the amount of steel reinforcing bar that can be removed from a plain concrete cross section. The application to real concrete linings, where shear resistance is ensured without shear reinforcement, shows that a large volume of rebar can be saved by the presence of steel fibers. This gives significant advantages in terms of durability and rapidity of tunnel construction.
Keywords
Fiber-reinforced Concrete; Efficiency Index; Ultimate Limit State; Cast-in Situ Concrete Lining; Precast Tunnel Segments
Ochsner, Jeffrey Karl. (2016). Meditations on the Empty Chair: The Form of Mourning and Reverie. American Imago, 73(2), 131 – 163.
Keywords
Vietnam-veterans-memorial; Photography; Thoughts
Van Den Wymelenberg, Kevin; Inanici, Mehlika. (2016). Evaluating a New Suite of Luminance-Based Design Metrics for Predicting Human Visual Comfort in Offices with Daylight. Leukos, 12(3), 113 – 138.
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Abstract
A new suite of visual comfort metrics is proposed and evaluated for their ability to explain the variability in subjective human responses in a mock private office environment with daylight. Participants (n = 48) rated visual comfort and preference factors, including 1488 discreet appraisals, and these subjective results were correlated against more than 2000 unique luminance-based metrics that were captured using high dynamic range photography techniques. Importantly, luminance-based metrics were more capable than illuminance-based metrics for fitting the range of human subjective responses to data from visual preference questionnaire items. No metrics based upon the entire scene ranked in the top 20 squared correlation coefficients, nor did any based upon illuminance or irradiance data, nor did any of the studied glare indices, luminance ratios, or contrast ratios. The standard deviation of window luminance was the metric that best fit human subjective responses to visual preference on seven of 12 questionnaire items (with r(2) = 0.43). Luminance metrics calculated using the horizontal 40. band (a scene-independent mask) and the window area (a scene-dependent mask) represented the majority of the top 20 squared correlation coefficients for almost all subjective visual preference questionnaire items. The strongest multiple regression model was for the semantic differential rating (too dim-too bright) of the window wall (R-adj(2) = 0.49) and was built upon three variables; standard deviation of window luminance, the 50th percentile luminance value from the lower view window, and mean luminance of the 40. horizontal band.
Keywords
Discomfort Glare; Controls; Daylighting; Visual Perception
Gase, Lauren N.; Defosset, Amelia R.; Gakh, Maxim; Harris, Celia; Weisman, Susan R.; Dannenberg, Andrew L. (2017). Review of Education-Focused Health Impact Assessments Conducted in the United States. Journal Of School Health, 87(12), 911 – 922.
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Abstract
BACKGROUNDHealth impact assessment (HIA) provides a structured process for examining the potential health impacts of proposed policies, plans, programs, and projects. This study systematically reviewed HIAs conducted in the United States on prekindergarten, primary, and secondary education-focused decisions. METHODSRelevant HIA reports were identified from web sources in late 2015. Key data elements were abstracted from each report. Four case studies were selected to highlight diversity of topics, methods, and impacts of the assessment process. RESULTSTwenty HIAs completed in 2003-2015 from 8 states on issues related to prekindergarten through secondary education were identified. The types of decisions examined included school structure and funding, transportation to and from school, physical modifications to school facilities, in-school physical activity and nutrition, and school discipline and climate. Assessments employed a range of methods to characterize the nature, magnitude, and severity of potential health impacts. Assessments fostered stakeholder engagement and provided health-promoting recommendations, some of which were subsequently incorporated into school policies. CONCLUSIONSHealth impact assessment is a promising tool that education, health, and other stakeholders can use to maximize the health and well-being of students, families, and communities.
Keywords
Decision Making; Elementary Schools; High Schools; Medical Policy; Medline; Nutrition; Online Information Services; Research Funding; Student Health; Systematic Reviews (medical Research); Search Engines; Physical Activity; Health Impact Assessment; United States; Collaboration; Policy; Public Health; Academic-achievement; Programs
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