Acolin, Arthur; Calem, Paul; Jagtiani, Julapa; Wachter, Susan. (2018). First-Time Homebuyers: Toward a New Measure. Cityscape, 20(1), 193 – 204.
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Abstract
Existing data sources show divergent estimates of the number of homes purchased by first-time homebuyers as a share of all home purchases. In this article, we use a new dataset to construct a time series of the share of first-time homebuyers. This series, based on the Federal Reserve Bank of New York Equifax Consumer Credit Panel, shows a significant decline in the share of first-time homebuyers, particularly among young households, consistent with the decline in homeownership in this age cohort since the early 2000s.
Acolin, Arthur; Vitiello, Domenic. (2018). Who Owns Chinatown: Neighbourhood Preservation and Change in Boston and Philadelphia. Urban Studies, 55(8), 1690 – 1710.
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Abstract
The survival of Chinatowns and other ethnic enclaves in cities is largely determined by who owns property. Ethnic enclaves such as Chinatowns have traditionally played important economic, social and cultural functions as places for recent immigrants to live and work, though Chinatowns have long faced redevelopment pressures. In North America, as Chinese immigrants and their descendants settle in the suburbs, and as historic Chinatowns’ locations close to revitalising downtowns attract increasing investment, the future of these historic enclaves is shaped by various, often intense and divergent, forces. This article describes changes in the patterns of property ownership in Boston and Philadelphia’s downtown Chinatowns over the last decade (2003–2013) and relates them to changes and continuities in these neighbourhoods’ population, commercial activities and building stock. The trends we observe simultaneously reinforce and complicate debates about gentrification and longstanding efforts to preserve these Chinatowns as ethnic Chinese residential, commercial, and cultural centres.]
Keywords
Chinatown, Ethnic Enclave, Neighbourhood Change, Ownership
Jon, Ihnji; Huang, Shih-kai; Lindell, Michael K. (2018). Perceptions and Reactions to Tornado Warning Polygons: Would a Gradient Polygon Be Useful? International Journal Of Disaster Risk Reduction, 30, 132 – 144.
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Abstract
To better understand people's interpretations of National Weather Service's tornado warning polygons, 145 participants were shown 22 hypothetical scenarios in one of four displays-deterministic polygon, deterministic polygon + radar image, gradient polygon, and gradient polygon + radar image. Participants judged each polygon's numerical strike probability (p(s)) and reported the likelihood of taking seven different response actions. The deterministic polygon display produced p(s) that were highest at the polygon's centroid and declined in all directions from there. The deterministic polygon + radar display, the gradient polygon display, and the gradient polygon + radar display produced p(s) that were high at the polygon's centroid and also at its edge nearest the tornadic storm cell. Overall, p(s) values were negatively related to resuming normal activities, but positively correlated with expectations of resuming normal activities, seeking information from social sources, seeking shelter, and evacuating by car. These results replicate the finding that participants make more appropriate p(s) judgments when polygons are presented in their natural context of radar images than when the polygons are presented in isolation and that gradient displays appear to provide no appreciable benefit. The fact that p(s) judgments had moderately positive correlations with both sheltering (a generally appropriate response) and evacuation (a generally inappropriate response) provides experimental confirmation that people threatened by actual tornadoes are conflicted about which protective action to take.
Keywords
Protective Action; Uncertainty; Risk; Psychology; Casualties; Tornado Warning Polygons; Risk Perceptions; Protective Actions
Ochsner, Jeffrey Karl. (2018). The Experience of Prospect and Refuge: Frank Lloyd Wright’s Houses as Holding Environments. American Imago, 75(2), 179 – 211.
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Keywords
Reverie
Kang, Bumjoon; Moudon, Anne V.; Hurvitz, Philip M.; Saelens, Brian E. (2018). Increased Walking’s Additive and No Substitution Effect on Total Physical Activity. Medicine & Science In Sports & Exercise, 50(3), 468 – 475.
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Abstract
Purpose We assessed the associations between a change in time spent walking and a change in total physical activity (PA) time within an urban living adult sample to test for additive or substitution effects. Methods Participants living in the greater Seattle area were assessed in 2008-2009 and again 1-2 yr later (2010-2011). At each time point, they wore accelerometers and GPS units and recorded trips and locations in a travel diary for seven consecutive days. These data streams were combined to derive a more objective estimate of walking and total PA. Participants also completed the International Physical Activity Questionnaire to provide self-reported estimates of walking and total PA. Regression analyses assessed the associations between within-participant changes in objective and self-reported walking and total PA. Results Data came from 437 participants. On average, a 1-min increase in total walking was associated with an increase in total PA of 1 min, measured by objective data, and 1.2-min, measured by self-reported data. A similar additive effect was consistently found with utilitarian, transportation, or job-related walking, measured by both objective and self-reported data. For recreational walking, the effect of change was mixed between objective and self-reported results. Conclusion Both objective and self-reported data confirmed an additive effect of utilitarian and total walking on PA.
Keywords
Accelerometers; Global Positioning System; Metropolitan Areas; Questionnaires; Recreation; Self-evaluation; Time; Walking; Physical Activity; Accelerometer; Gps; Ipaq; Longitudinal Study; Self-reported Measures; Light-rail Construction; Built Environment; Accelerometer Data; Older-adults; Urban Form; Transit Use; Travel; Neighborhood; Interventions; Calibration
Simonen, K.; Huang, M.; Aicher, C.; Morris, P. (2018). Embodied Carbon as a Proxy for the Environmental Impact of Earthquake Damage Repair. Energy And Buildings, 164, 131 – 139.
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Abstract
In evaluating the life cycle environmental impacts of buildings, the contributions of seismic damage are rarely considered. In order to enable a more comprehensive assessment of a building's environmental impact by accounting for seismic events, this project developed an environmental impact database of building component seismic damage - the largest of its kind known to date - by combining data from Carnegie Mellon University's Economic Input-Output Life Cycle Analysis (LCA) database with cost estimates of repair previously developed for FEMA's Performance Assessment Calculation Tool (PACT), a software that models probabilistic seismic damage in buildings. Fifteen indicators of environmental impacts were calculated for the repair of approximately 800 building components for up to five levels of seismic damage, capturing 'embodied' impacts related to cradle-to-gate manufacturing of building materials, products, and equipment. Analysis of the data revealed that non-structural and architectural finishes often dominated the environmental impacts of seismic damage per dollar spent in repair. A statistical analysis was performed on the data using Principal Component Analysis, confirming that embodied carbon, a popular metric for evaluating environmental impacts in building LCAs, is a suitable proxy for other relevant environmental impact metrics when assessing the impact of repairing earthquake damage of buildings. (C) 2018 Elsevier B.V. All rights reserved.
Keywords
Life-cycle Assessment; Input-output; Buildings; Life Cycle Assessment; Seismic Analysis; Performance-based Design; Economic Input-output; Principal Component Analysis; Energy And Climate Change; Architectural Engineering; Carbon; Carbon Cycle; Earthquake Damage; Earthquakes; Environmental Impact; Environmental Management; Databases; Finishes; Environmental Assessment; Building Components; Construction Materials; Life Cycle Engineering; Life Cycle Analysis; Data Bases; Damage Assessment; Aseismic Buildings; Statistical Analysis; Equipment Costs; Cost Estimates; Data Processing; Data Analysis; Seismic Activity; Cost Analysis; Principal Components Analysis; Performance Assessment; Life Cycles; Repair; Impact Damage; Building Materials; Economic Analysis; Software
Kang, Mingyu; Moudon, Anne V.; Hurvitz, Philip M.; Saelens, Brian E. (2018). Capturing Fine-Scale Travel Behaviors: A Comparative Analysis between Personal Activity Location Measurement System (PALMS) and Travel Diary. International Journal Of Health Geographics, 17(1).
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Abstract
BackgroundDevice-collected data from GPS and accelerometers for identifying active travel behaviors have dramatically changed research methods in transportation planning and public health. Automated algorithms have helped researchers to process large datasets with likely fewer errors than found in other collection methods (e.g., self-report travel diary). In this study, we compared travel modes identified by a commonly used automated algorithm (PALMS) that integrates GPS and accelerometer data with those obtained from travel diary estimates.MethodsSixty participants, who made 2100 trips during seven consecutive days of data collection, were selected from among the baseline sample of a project examining the travel behavior impact of a new light rail system in the greater Seattle, WA (USA) area. GPS point level analyses were first conducted to compare trip/place and travel mode detection results using contingency tables. Trip level analyses were then performed to investigate the effect of proportions of time overlap between travel logs and device-collected data on agreement rates. Global performance (with all subjects' data combined) and subject-level performance of the algorithm were compared at the trip level.ResultsAt the GPS point level, the overall agreement rate of travel mode detection was 77.4% between PALMS and the travel diary. The agreement rate for vehicular trip detection (84.5%) was higher than for bicycling (53.5%) and walking (58.2%). At the trip level, the global performance and subject-level performance of the PALMS algorithm were 46.4% and 42.4%, respectively. Vehicular trip detection showed highest agreement rates in all analyses. Study participants' primary travel mode and car ownership were significantly related to the subject-level mode agreement rates.ConclusionsThe PALMS algorithm showed moderate identification power at the GPS point level. However, trip level analyses found lower agreement rates between PALMS and travel diary data, especially for active transportation. Testing different PALMS parameter settings may serve to improve the detection of active travel and help expand PALMS's applicability in geographically different urbanized areas with a variety of travel modes.
Keywords
Transportation Planning; Public Health; Accelerometers; Global Positioning System; Voyages & Travels; Cycling; Algorithms; Accelerometer; Automated Algorithm; Gis; Gps; Places; Trips; Global Positioning Systems; Physical-activity; Data-collection; Health Research; Gps Data; Accelerometry; Validity
Sprague, Tyler S. (2018). Jack Christiansen’s Cylindrical Concrete Shells. Journal Of The International Association For Shell And Spatial Structures, 59(2), 131 – 140.
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Abstract
This article examines the early thin shell concrete designs of the structural engineer Jack Christiansen (1927-2017), a 2016 recipient of the Eduardo Torroja Medal. With no proper training in shell behavior, Christiansen started his career designing cylindrical concrete shells based on the 1952 American Society of Civil Engineers (ASCE) Manual 31. This manual, and its approach to solving indeterminate behavior, both directed Christiansen's early design and provided a framework for significant creative work outside its bounds. His designs of long, spanning shells and short, arching shells (between 1954 and 1958) were adapted to a variety of architectural spaces, utilizing emerging structural methods like prestressing. These designs constitute the first era of Christiansen's career, and set the stage for more varied shell geometries to come.
Keywords
Historic Structures; Concrete Shells; Cylindrical Shells; Modernism; Indeterminate Analysis Methods
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
Stewart, Orion T.; Moudon, Anne Vernez; Littman, Alyson J.; Seto, Edmund; Saelens, Brian E. (2018). The Association between Park Facilities and Duration of Physical Activity During Active Park Visits. Journal Of Urban Health, 95(6), 869 – 880.
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Abstract
Public parks provide places for urban residents to obtain physical activity (PA), which is associated with numerous health benefits. Adding facilities to existing parks could be a cost-effective approach to increase the duration of PA that occurs during park visits. Using objectively measured PA and comprehensively measured park visit data among an urban community-dwelling sample of adults, we tested the association between the variety of park facilities that directly support PA and the duration of PA during park visits where any PA occurred. Cross-classified multilevel models were used to account for the clustering of park visits (n=1553) within individuals (n=372) and parks (n=233). Each additional different PA facility at a park was independently associated with a 6.8% longer duration of PA bouts that included light-intensity activity, and an 8.7% longer duration of moderate to vigorous PA time. Findings from this study are consistent with the hypothesis that more PA facilities increase the amount of PA that visitors obtain while already active at a park.
Keywords
Park Facilities; Physical Activity; Park Use; Recreation; Built Environment; Global Positioning System; Accelerometer; Gis; Gps; Accelerometer Data; United-states; Adults; Proximity; Features; Walking; Size; Attractiveness; Improvements; Environment; Parks & Recreation Areas; Parks; Luminous Intensity; Clustering; Urban Areas