Kang, Bumjoon; Moudon, Anne V.; Hurvitz, Philip M.; Reichley, Lucas; Saelens, Brian E. (2013). Walking Objectively Measured: Classifying Accelerometer Data with GPS and Travel Diaries. Medicine & Science In Sports & Exercise, 45(7), 1419 – 1428.
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Abstract
Purpose: This study developed and tested an algorithm to classify accelerometer data as walking or nonwalking using either GPS or travel diary data within a large sample of adults under free-living conditions. Methods: Participants wore an accelerometer and a GPS unit and concurrently completed a travel diary for seven consecutive days. Physical activity (PA) bouts were identified using accelerometry count sequences. PA bouts were then classified as walking or nonwalking based on a decision-tree algorithm consisting of seven classification scenarios. Algorithm reliability was examined relative to two independent analysts' classification of a 100-bout verification sample. The algorithm was then applied to the entire set of PA bouts. Results: The 706 participants' (mean age = 51 yr, 62% female, 80% non-Hispanic white, 70% college graduate or higher) yielded 4702 person-days of data and had a total of 13,971 PA bouts. The algorithm showed a mean agreement of 95% with the independent analysts. It classified PA into 8170 walking bouts (58.5 %) and 5337 nonwalking bouts (38.2%); 464 bouts (3.3%) were not classified for lack of GPS and diary data. Nearly 70% of the walking bouts and 68% of the nonwalking bouts were classified using only the objective accelerometer and GPS data. Travel diary data helped classify 30% of all bouts with no GPS data. The mean + SD duration of PA bouts classified as walking was 15.2 + 12.9 min. On average, participants had 1.7 walking bouts and 25.4 total walking minutes per day. Conclusions: GPS and travel diary information can be helpful in classifying most accelerometer-derived PA bouts into walking or nonwalking behavior.
Keywords
Walking; Algorithms; Decision Trees; Geographic Information Systems; Research Funding; Travel; Accelerometry; Diary (literary Form); Descriptive Statistics; Algorithm; Classification; Physical Activity; Walk Trip; Global Positioning Systems; Physical-activity; Environment; Behaviors; Validity; Location
Dannenberg, Andrew L.; Ricklin, Anna; Ross, Catherine L.; Schwartz, Michael; West, Julie; White, Steve; Wier, Megan L. (2014). Use of Health Impact Assessment for Transportation Planning Importance of Transportation Agency Involvement in the Process. Transportation Research Record, 2452, 71 – 80.
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Abstract
A health impact assessment (HIA) is a tool that can be used to inform transportation planners of the potential health consequences of their decisions. Although dozens of transportation-related HIAs have been completed in the United States, the characteristics of these HIAs and the interactions between public health professionals and transportation decision makers in these HIM have not been documented. A master list of completed HIAs was used to identify transportation-related HIAs. Seventy-three transportation-related HIAs conducted in 22 states between 2004 and 2013 were identified. The HIAs were conducted for projects such as road redevelopments, bridge replacements, and development of trails and public transit. Policies such as road pricing, transit service levels, speed limits, complete streets, and safe routes to schools were also assessed. Five HIAs in which substantial interactions between public health and transportation professionals took place during and after the HIA were examined in detail and included HIAs of the road pricing policy in San Francisco, California; a bridge replacement in Seattle, Washington; new transit lines in Baltimore, Maryland, and Portland, Oregon; and the BeltLine transit, trails, and parks project in Atlanta, Georgia. Recommendations from the HIAs led to changes in decisions in some cases and helped to raise awareness of health issues by transportation decision makers in all cases. HIAs are now used for many topics in transportation. The range of involvement of transportation decision makers in the conduct of HIAs varies. These case studies may serve as models for the conduct of future transportation-related HIAs, because the involvement of transportation agencies may increase the likelihood that an HIA will influence subsequent decisions.
Keywords
Policy; Inequalities; Benefits; Justice; Oregon
Lee, Namhun; Schaufelberger, John E. (2014). Risk Management Strategies for Privatized Infrastructure Projects: Study of the Build-Operate-Transfer Approach in East Asia and the Pacific. Journal Of Management In Engineering, 30(3).
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Abstract
Private-public partnerships have been adopted for the development of public infrastructure to meet the growing demand for public services. Many Asian countries have used the build-operate-transfer (BOT) approach to develop public infrastructure projects. However, the potential benefits of undertaking a BOT project are accompanied by corresponding risks from the private sector's perspective. The objectives of this study are (1)to identify and discuss major risks inherent in the East Asia and Pacific regions, and (2)to propose risk management strategies for future BOT projects to be successful. This paper reports the results of five case study analyses undertaken to review their primary risks and mitigated methods. In addition, this paper proposes some strategies for future BOT projects. Two main categories of risks were analyzed: general risks and project-specific risks. Risk management strategies were suggested for each category of risk. The main finding of this study indicates that the private sector cannot be the only participant in risk management. The host government's active support is the most essential factor for the profitability and economic viability of a BOT project in the East Asia and Pacific regions.
Keywords
Organisational Aspects; Project Management; Public Administration; Public Utilities; Risk Management; Structural Engineering; Risk Management Strategies; Privatized Infrastructure Projects; Build-operate-transfer Approach; East Asia; Private-public Partnerships; Public Services; Asian Countries; Public Infrastructure Projects; Pacific Regions; Future Bot Projects; Project-specific Risks; General Risks; Build-operate-transfer; Privatized Infrastructure
Barrington, Wendy E.; Beresford, Shirley A. A.; Koepsell, Thomas D.; Duncan, Glen E.; Moudon, Anne Vernez. (2015). Worksite Neighborhood and Obesogenic Behaviors: Findings among Employees in the Promoting Activity and Changes in Eating (PACE) Trial. American Journal Of Preventive Medicine, 48(1), 31 – 41.
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Abstract
Background: Understanding mechanisms linking neighborhood context to health behaviors may provide targets for increasing lifestyle intervention effectiveness. Although associations between home neighborhood and obesogenic behaviors have been studied, less is known about the role of worksite neighborhood. Purpose: To evaluate associations between worksite neighborhood context at baseline (2006) and change in obesogenic behaviors of adult employees at follow-up (2007-2009) in a worksite randomized trial to prevent weight gain. Methods: Worksite property values were used as an indicator of worksite neighborhood SES (NSES). Worksite neighborhood built environment attributes associated with walkability were evaluated as explanatory factors in relationships among worksite NSES, diet, and physical activity behaviors of employees. Behavioral data were collected at baseline (2005-2007) and follow-up (2007-2009). Multilevel linear and logistic models were constructed adjusting for covariates and accounting for clustering within worksites. Product-of-coefficients methods were used to assess mediation. Analyses were performed after study completion (2011-2012). Results: Higher worksite NSES was associated with more walking (OR = 1.16, 95% CI = 1.03, 1.30, p = 0.01). Higher density of residential units surrounding worksites was associated with more walking and eating five or more daily servings of fruits and vegetables, independent of worksite NSES. Residential density partially explained relationships among worksite NSES, fruit and vegetable consumption, and walking. Conclusions: Worksite neighborhood context may influence employees' obesogenic behaviors. Furthermore, residential density around worksites could be an indicator of access to dietary and physical activity-related infrastructure in urban areas. This may be important given the popularity of worksites as venues for obesity prevention efforts. Published by Elsevier Inc. on behalf of American Journal of Preventive Medicine.
Keywords
Health Behavior; Food Habits; Lifestyles & Health; Prevention Of Obesity; Employee Health Promotion; Follow-up Studies (medicine); Local Food Environment; Dietary Energy Density; Body-mass Index; Socioeconomic-status; Physical-activity; Built Environment; Longitudinal-associations; Walking Behavior; Restaurant Use; Weight-gain
Shakouri, Mahmoud; Lee, Hyun Woo; Choi, Kunhee. (2015). PACPIM: New Decision-Support Model of Optimized Portfolio Analysis for Community-Based Photovoltaic Investment. Applied Energy, 156, 607 – 617.
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Abstract
Inherent in large-scale photovoltaic (PV) investments is volatility that stems from a unique set of spatial factors, such as shading, building orientation, and roof slope, which can significantly affect both the level of risk and the return on investment. In order to systematically assess and manage the volatility, this study seeks to create a quantitative decision-support model: Portfolio Analysis for Community-based PV Investment Model (PACPIM). Focusing on residential PV systems, PACPIM determines optimized portfolios by applying the Mean Variance Portfolio theory. The model is intended to play an instrumental role in: (1) maximizing the hourly electricity output of PV systems; (2) minimizing the hourly volatility in electricity output; and (3) optimizing the risk-adjusted performance of community-based PV investment. The application and framework of PACPIM were deployed with an actual residential community consisting of 24 houses and their simulated data utilizing PVWatts (R) for estimating hourly electricity production. Results reveal that the optimized portfolios developed by PACPIM (1) increased annual electricity output of PV systems by 4.6%; (2) reduced the volatility in electricity output by 4.3%; and (3) offered the highest risk-adjusted performance among all possible portfolios based on the Sharpe ratios. This study is expected to effectively assist project owners and investors in systematically assessing their community-based PV projects and in developing optimized investment strategies. (C) 2015 Elsevier Ltd. All rights reserved.
Keywords
Photovoltaic Cells; Rate Of Return; Electricity; Dwellings; Electric Utilities; Community-based Investments; Decision-support Model; Mean–variance Portfolio Theory; Residential Photovoltaic Systems; Solar Energy; Decision Support Systems; Investment; Photovoltaic Power Systems; Large-scale Photovoltaic Investments; Spatial Factors; Shading; Building Orientation; Roof Slope; Return On Investment; Quantitative Decision-support Model; Portfolio Analysis For Community-based Pv Investment Model; Pacpim; Residential Pv Systems; Mean-variance Portfolio Theory; Hourly Electricity Output; Hourly Volatility; Risk-adjusted Performance; Hourly Electricity Production Estimation; Community-based Pv Projects; Optimized Investment Strategies; Romanian National Strategy; Renewable Energy; Public-attitudes; Wind Power; Pv Module; Performance; Implementation; Efficiency; Form; Economic Theory; Electricity Generation; Models; Risk; Shade; Solar Collectors
Drewnowski, Adam; Aggarwal, Anju; Cook, Andrea; Stewart, Orion; Moudon, Anne Vernez. (2016). Geographic Disparities in Healthy Eating Index Scores (HEI-2005 and 2010) by Residential Property Values: Findings from Seattle Obesity Study (SOS). Preventive Medicine, 83, 46 – 55.
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Abstract
Background. Higher socioeconomic status (SES) has been linked with higher-quality diets. New GIS methods allow for geographic mapping of diet quality at a very granular level. Objective. To examine the geographic distribution of two measures of diet quality: Healthy Eating Index (HEI 2005 and HEI 2010) in relation to residential property values in Seattle-King County. Methods. The Seattle Obesity Study (SOS) collected data from a population-based sample of King County adults in 2008-09. Socio-demographic data were obtained by 20-min telephone survey. Dietary data were obtained from food frequency questionnaires (FFQs). Home addresses were geocoded to the tax parcel and residential property values were obtained from the King County tax assessor. Multivariable regression analyses using 1116 adults tested associations between SES variables and diet quality measured (HEI scores). Results. Residential property values, education, and incomes were associated with higher HEI scores in bivariate analyses. Property values were not collinear with either education or income. In adjusted multivariable models, education and residential property were better associated with HEI, compared to than income. Mapping of HEI-2005 and HEI-2010 at the census block level illustrated the geographic distribution of diet quality across Seattle-King County. Conclusion. The use of residential property values, an objective measure of SES, allowed for the first visual exploration of diet quality at high spatial resolution: the census block level. (C) 2015 Elsevier Inc. All rights reserved.
Keywords
Obesity Treatment; Prevention Of Obesity; Disease Mapping; Socioeconomics; Multivariate Analysis; Population Geography; Census; Diet; Housing; Nutrition Policy; Questionnaires; Research Funding; Socioeconomic Factors; Body Mass Index; Health Equity; Cross-sectional Method; Economics; Seattle (wash.); Washington (state); Diet Quality; Geographic Information Systems; Healthy Eating Index; Residential Property Values; Socio-economic Status; Local Food Environment; Vitamin-e Consumption; Socioeconomic Position; United-states; Social-class; Energy-density; Association; Indicators; Trends
Kim, Tae-hyung; Lee, Hyun Woo; Hong, Seok-woo. (2016). Value Engineering for Roadway Expansion Project over Deep Thick Soft Soils. Journal Of Construction Engineering And Management, 142(2).
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Abstract
A roadway expansion that takes place on soft ground is susceptible to differential settlement because of the high consolidation of soft soils. Therefore, steps must be taken to lessen the risk of such settlement; yet, this often only results in costly drainage solutions. In that, applying a systematic value engineering (VE) process can be beneficial to develop cost-effective design alternatives. However, VE studies specifically targeting for this problem are absent from the field. Thus, the goal of this study is to supplement this knowledge gap by applying a systematic VE process to an expansion project on soft ground to demonstrate the benefits of performing VE. A case study was performed on an expansion project over a soft soil layer approximately 50m thick. Through the VE process, the original design was reviewed, problems were discussed, and three alternatives were proposed. Then value analysis techniques were applied to evaluate these alternatives in terms of cost saving, function improvement, and value improvement with respect to the original design. The VE process and design alternatives as applied in this study are expected to serve as a guideline for engineers and decision-makers in roadway expansion projects on soft ground. (C) 2015 American Society of Civil Engineers.
Keywords
Construction Industry; Costing; Project Management; Road Building; Soil; Value Engineering; Engineers; Decision-makers; Value Improvement; Function Improvement; Knowledge Gap; Cost-effective Design; Deep Thick Soft Soils; Soft Ground; Roadway Expansion Project; Systematic Value Engineering Process; Value Engineering (ve); Job Plan; Roadway Expansion; Deep Soft Ground; Differential Settlement; Cost Saving; Project Planning And Design
Schmiedeskamp, Peter; Zhao, Weiran. (2016). Estimating Daily Bicycle Counts in Seattle, Washington, from Seasonal and Weather Factors. Transportation Research Record, 2593, 94 – 102.
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Abstract
This paper examines the relationship between several seasonal and weather factors and bicycle ridership from 2 years of automated bicycle counts at a location in Seattle, Washington. The authors fitted a negative binomial model and then estimated quantities of interest using counterfactual simulation. The findings confirm the significance of season (+), temperature (+), precipitation (), as well as holidays (-), day of the week (+ for Monday through Saturday, relative to Sunday), and an overall trend (+). This paper improves on prior work by demonstrating the use of the negative binomial instead of a Poisson model, which is appropriate given the potential for overdispersion, as observed in these data. In addition to validating the significance of factors identified from the literature, this paper contributes methodologically through its intuitive visualization of effect sizes to nonstatistical audiences. The authors believe that the combination of model type and counterfactual simulation and visualization reflects a reasonable compromise between model complexity and interpretability. Results such as these can aid policy makers and planners in understanding bicycle travel demand elasticities and in guiding interventions aimed at increasing rates of bicycling. The methods presented are fully reproducible and invite adaptation to other locations.
Chaix, Basile; Duncan, Dustin; Vallee, Julie; Vernez-moudon, Anne; Benmarhnia, Tarik; Kestens, Yan. (2017). The Residential Effect Fallacy in Neighborhood and Health Studies Formal Definition, Empirical Identification, and Correction. Epidemiology, 28(6), 789 – 797.
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Abstract
Background: Because of confounding from the urban/rural and socioeconomic organizations of territories and resulting correlation between residential and nonresidential exposures, classically estimated residential neighborhood-outcome associations capture nonresidential environment effects, overestimating residential intervention effects. Our study diagnosed and corrected this residential effect fallacy bias applicable to a large fraction of neighborhood and health studies. Methods: Our empirical application investigated the effect that hypothetical interventions raising the residential number of services would have on the probability that a trip is walked. Using global positioning systems tracking and mobility surveys over 7 days (227 participants and 7440 trips), we employed a multilevel linear probability model to estimate the trip-level association between residential number of services and walking to derive a naive intervention effect estimate and a corrected model accounting for numbers of services at the residence, trip origin, and trip destination to determine a corrected intervention effect estimate (true effect conditional on assumptions). Results: There was a strong correlation in service densities between the residential neighborhood and nonresidential places. From the naive model, hypothetical interventions raising the residential number of services to 200, 500, and 1000 were associated with an increase by 0.020, 0.055, and 0.109 of the probability of walking in the intervention groups. Corrected estimates were of 0.007, 0.019, and 0.039. Thus, naive estimates were overestimated by multiplicative factors of 3.0, 2.9, and 2.8. Conclusions: Commonly estimated residential intervention-outcome associations substantially overestimate true effects. Our somewhat paradoxical conclusion is that to estimate residential effects, investigators critically need information on nonresidential places visited.
Keywords
Self-rated Health; Record Cohort; Physical-activity; Transportation Modes; Built Environment; Activity Spaces; Research Agenda; Risk-factors; Associations; Exposure
Nazari, Ahad; Vandadian, Shaghayegh; Abdirad, Hamid. (2017). Fuzzy AHP Model for Prequalification of Engineering Consultants in the Iranian Public Procurement System. Journal Of Management In Engineering, 33(2).
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Abstract
Prequalification of engineering consultants in the Iranian public procurement system is suffering from arbitrary processes and criteria that cannot effectively shortlist the increasing number of potential bidders. This study aims to develop a prequalification model that can serve as the basis for revising the existing regulations and criteria. The authors conducted interviews among experts to localize a framework of prequalification criteria. Fuzzy analytical hierarchy process (FAHP), accompanied by a survey among industry participants, was used to determine the importance level of decision criteria. The results confirmed that the existing guidelines cannot meet the expectations of the industry due to the overemphasis on the past performance of consultants and disregarding their current capabilities. For the international audience, this study clarifies that (1)the working culture of industry participants impacts their judgments on the importance level of intangible and tangible criteria used for prequalification processes, (2)short-listing consultants for long-term and fragmented data collection in national registration or project prequalification should be avoided, and (3)researchers must test FAHP models with different fuzzy scales because the success of the widely used fuzzy extent analysis method is highly dependent on the scale of fuzzy functions and judgments of decision makers.
Keywords
Analytic Hierarchy Process; Fuzzy Set Theory; Organisational Aspects; Procurement; Project Management; Public Relations; Tendering; Fuzzy Ahp Model; Project Prequalification Criteria; Iranian Public Procurement System; Bidders; Fuzzy Analytical Hierarchy Process; Industry Participants; International Audience; National Registration; Fuzzy Scales; Fuzzy Extent Analysis Method; Decision Makers; Engineering Consultants; Working Culture; Decision-making Model; Extent Analysis Method; Selection; Qualification; Contractors; Criteria; Consultants; Prequalification; Fuzzy; Analytical Hierarchy Process (ahp)