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Hoseok Sa

Research Interests: Regional econ. development (tech innovation, human capital, regional industry), Transportation planning/policy (travel behavior, mobility, sustainable transportation), intersection between planning (or transportation), population/public health, and climate change, and urban form

Higher Depression Risks in Medium- Than in High-Density Urban Form Across Denmark

Chen, T.-H. K., Horsdal, H. T., Samuelsson, K., Closter, A. M., Davies, M., Barthel, S., Pedersen, C. B., Prishchepov, A. V., & Sabel, C. E. (2023). Higher depression risks in medium- than in high-density urban form across Denmark. Science Advances, 9(21), eadf3760–eadf3760. https://doi.org/10.1126/sciadv.adf3760

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Abstract

Urban areas are associated with higher depression risks than rural areas. However, less is known about how different types of urban environments relate to depression risk. Here, we use satellite imagery and machine learning to quantify three-dimensional (3D) urban form (i.e., building density and height) over time. Combining satellite-derived urban form data and individual-level residential addresses, health, and socioeconomic registers, we conduct a case-control study (n = 75,650 cases and 756,500 controls) to examine the association between 3D urban form and depression in the Danish population. We find that living in dense inner-city areas did not carry the highest depression risks. Rather, after adjusting for socioeconomic factors, the highest risk was among sprawling suburbs, and the lowest was among multistory buildings with open space in the vicinity. The finding suggests that spatial land-use planning should prioritize securing access to open space in densely built areas to mitigate depression risks.

Scaling Down from the Neighborhood in Urban Planning Research and Practice: The Potential Benefits of a Micro-Scale Focus

Walter, R. J., Tillyer, M. S., Ramiller, A., & Acolin, A. (2023). Scaling Down from the Neighborhood in Urban Planning Research and Practice: The Potential Benefits of a Micro-Scale Focus. Journal of Planning Education and Research. https://doi.org/10.1177/0739456X231175593

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Abstract

The neighborhood has been the dominant spatial unit in urban planning since the early 20th century. Criticisms of the neighborhood unit include disagreements about defining boundaries, methodological challenges in capturing neighborhood effects, and negative impacts on communities. With advancements in data management, and public data available at smaller units (street block or property), quantitative analyses are possible at the micro-scale. This commentary draws on crime research and prevention to illustrate the benefits of micro-scale approaches to quantitative analyses in the field of urban planning, arguing that the devolution to smaller scales may be a vehicle for efficient resource allocation.

Utilizing Fractal Dimensions as Indicators to Detect Elements of Visual Attraction: A Case Study of the Greenway along Lake Taihu, China

Fan, R., Yocom, K. P., & Guo, Y. (2023). Utilizing Fractal Dimensions as Indicators to Detect Elements of Visual Attraction: A Case Study of the Greenway along Lake Taihu, China. Land (Basel), 12(4), 883–. https://doi.org/10.3390/land12040883

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Abstract

It is widely acknowledged that the quality of greenway landscape resources enhances the visual appeal of people. While most studies have evaluated visual perception and preference, few have considered the relationship between the distribution of greenways in relation to the proximity of water bodies such as lakes and rivers. Such an investigation requires an in-depth analysis of how to plan and design greenways in order to better enhance people's willingness to access and utilize them. In this research we propose specific color brightness and contour visual attraction elements to further discuss the quality of greenway landscape resources in the rapidly urbanizing Lake Taihu region of China. Specifically, we utilize a common method in fractal theory analysis called counting box dimension to calculate and analyze the sample images. The method generates data on fractal dimension (FD) values of two elements; the optimal fractal dimension threshold range; the characteristics exhibited by the maximum and minimum fractal dimension values in the greenway landscape; and the relationship between the two visual attraction elements allowing us to derive distribution of the greenway and water bodies. The results reveal that greenway segments with high values of the visual attraction element of color brightness fractal dimension (FD) are significantly closer to the lake than those subject to high values of the visual attraction element. Some segments are even close to the lake surface, which is because the glare from the direct sunlight and the reflection from the lake surface superimposed on each other, so that the greenway near the lake surface is also affected by the brightness and shows the result of high color brightness values. However, the greenway segments with high values of contour element FD are clearly more influenced by plants and other landscape elements. This is due to the rich self-similarity of the plants themselves. Most of the greenway segments dominated by contour elements are distant from the lake surface. Both color brightness and contour elements are important indicators of the quality of the visual resources of the Lake Taihu Greenway landscape. This reveals that the determination of the sub-dimensional values of color brightness (1.7608, 1.9337) and contour (1.7230, 1.9006) visual attraction elements and the optimal threshold range (1.7608, 1.9006) can provide theoretical implications for the landscape planning and design of lake-ring type greenways and practical implications for assessing the quality of visual resources in greenway landscapes.

Keywords

color brightness; contour; visual attraction; fractal dimension (FD); boxplot; Lake Taihu

Does Compact Development Mitigate Urban Thermal Environments? Influences of Smart Growth Principles on Land Surface Temperatures in Los Angeles and Portland

Won, Jongho, and Meen Chel Jung. 2023. Does Compact Development Mitigate Urban Thermal Environments? Influences of Smart Growth Principles on Land Surface Temperatures in Los Angeles and Portland. Sustainable Cities and Society 90.

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Abstract

The smart growth paradigm has emerged as a major planning framework to respond to the adverse outcomes of reckless development, but its influences on urban thermal environments are underexplored in the scholarly literature. Since elevated land surface temperature (LST) is closely related to the physical expansion of developed areas, it is necessary to identify the effects of smart growth strategies on LST. This study, therefore, investigated the relationships between LST, landscape variables, and smart growth variables at the census block group level in two distinct urban locales: the City of Los Angeles, California, and the City of Portland, Oregon, from 2010 to 2018. Through multivariate analyses—including the principal component analysis (PCA), K-means clustering, analysis of covariance (ANCOVA), and regression models—this study revealed the potential of urban forms promoted by the smart growth principles comprehensively to mitigate LST. Given the different features of built environments and planning systems between the two cities, the results of this study also indicate the necessity of considering local contexts rather than suggesting a “one-size-fits-all” policy.

Keywords

Smart growth; Compact development; Land surface temperature; Urban form; Landscape

Coastal Adaptations with the Shoalwater Bay Tribe: Centering Place and Community to Address Climate Change and Social Justice

The proposed community-based participatory action research project is a collaborative research, planning and design initiative that will enable a UW research team to work with the Shoalwater Bay Indian Tribe to explore sustainable and culturally relevant strategies for an upland expansion in response to climate change-driven sea level rise and other threats to their coastal ecosystems and community. The situation is urgent as the reservation is located in the most rapidly eroding stretch of Pacific coastline in the US, on near-sea-level land vulnerable also to catastrophic tsunamis. The project will advance the Tribe’s master plan and collaboratively develop a model of climate adaptive, culture-affirming and change-mitigating environmental strategies for creating new infrastructure, housing and open spaces in newly acquired higher elevation land adjacent to the reservation. Design and planning strategies will draw on culturally-based place meanings and attachments to support a sense of continuity, ease the transition, and create new possibilities for re-grounding. Sustainable strategies generated by the project will draw on both traditional ecological knowledge and scientific modeling of environmental change. The project will involve the following methods and activities:

  • The creation of a Tribal scientific and policy Advisory Board with representatives from the Tribal Council, elder, youth, state and county agencies, and indigenous architects and planners;
  • Student-led collaborative team-building and research activities that will also engage Tribal youth;
  • Systematic review of the Tribe’s and neighboring county plans;
  • Interviews, focus groups and community workshops to identify priority actions, needs and strategies;
  • Adaptation of existing research on sustainable master planning, design and carbon storing construction materials; and
  • The development of culturally meaningful and sustainable building prototypes.

Deliverables include a report of findings summarizing community assets and values, and priorities for the upland expansion vetted by Tribal leaders, documentation and evaluation of the UW-community partnership and engagement process, digitized web- based geo-narratives and story maps and technical recommendations for culturally-informed schematic designs, sustainable construction methods and low-embodied carbon storing materials. The project process and outcomes will have broad applicability for other vulnerable coastal communities and can be used to support their climate adaptation efforts as well.

Research Team
Principal Investigator: Daniel Abramson, College of Built Environments, Urban Design and Planning, University of Washington
Community Lead: Jamie Judkins, Shoalwater Bay Indian Tribe

University of Washington Partners:
Rob Corser, Associate Professor, Department of Architecture
Julie Kriegh, Affiliate Lecturer, Departments of Construction Management and Architecture and Principal, Kriegh Architecture Studios | Design + Research
Jackson Blalock, Community Engagement Specialist, Washington Sea Grant
Lynne Manzo, Professor, Department of Landscape Architecture
Kristiina Vogt, Professor, School of Environmental and Forest Sciences

Community Partners:
Daniel Glenn, AIA, NCARB, Principal, 7 Directions Architects/Planners 
John David “J.D.” Tovey III, Confederated Tribes of the Umatilla Indian Reservation
Timothy Archer Lehman, Design and Planning Consultant and Lecturer

Mediating Role of Walking between Perceived and Objective Walkability and Cognitive Function in Older Adults

Kim, Boeun, Barrington, Wendy E., Dobra, Adrian, Rosenberg, Dori, Hurvitz, Philip, & Belza, Basia. (2022). Mediating Role of Walking between Perceived and Objective Walkability and Cognitive Function in Older Adults. Health & Place, 79.

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Abstract

The aim of this study was to examine the role of walking in explaining associations between perceived and objective measures of walkability and cognitive function among older adults. The study employed a cross-sectional design analyzing existing data. Data were obtained from the Adult Changes in Thought Activity Monitor study. Cognitive function and perceived walkability were measured by a survey. Objective walkability was measured using geographic information systems (GIS). Walking was measured using an accelerometer. We tested the mediating relationship based on 1,000 bootstrapped samples. Perceived walkability was associated with a 0.04 point higher cognitive function score through walking (p = 0.006). The mediating relationship accounted for 34% of the total relationship between perceived walkability and cognitive function. Walking did not have a significant indirect relationship on the association between objective walkability and cognitive function. Perceived walkability may be more relevant to walking behavior than objective walkability among older adults. Greater levels of perceived walkability may encourage older adults to undertake more walking, and more walking may in turn improve cognitive function in older adults.

Keywords

Built environment; Cognitive function; Walking; Mediation analysis; Older adults

Impact of a Light Rail Transit Line on Physical Activity: Findings from the Longitudinal Travel Assessment and Community (TRAC) Study

Saelens, Brian E., Hurvitz, Philip M., Zhou, C., Colburn, T., Marchese, A., & Moudon, Anne Vernez (2022). Impact of a Light Rail Transit Line on Physical Activity: Findings from the Longitudinal Travel Assessment and Community (TRAC) Study. Journal of Transport & Health, 27.

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Abstract

Increasing transit infrastructure could increase transit use and result in higher physical activity if users actively travel to access transit. Few studies have rigorously examined transit use and physical activity change from before to years after among residents living close versus farther away from new transit options.Methods: An initial sample (n = 722) of residents living either close (1 mile network distance; unexposed) from future new light rail transit (LRT) stops in the Seattle/King County area were recruited and assessed prior to LRT opening and again 1-2 and 3-4 years later. At each assessment timepoint, residents wore an accelerometer and GPS data logger for 7 days and completed a 7-day travel log and demographic and attitudinal survey. Difference-in-difference analyses examined longitudinal change between those exposed versus unexposed to LRT in physical activity, walking (both utilitarian and recreational), and transit-related walking, and transit use.Results: There was no differential change by LRT exposure in overall physical activity (including or not including light intensity physical activity), recreational walking, or utilitarian walking, with most decreasing significantly in both exposure conditions through follow-ups. There was a differential change in transit-related walking, with those exposed to LRT slightly increasing such physical activity to the most distal follow-up, but the difference from the unexposed condition was modest (<2 min/day). There was no substantial differential change over time in transit use by LRT exposure.Conclusions: Exposure to a new light rail line did not markedly change the frequency of transit use of nearby residents, but did result in a small increase in transit-related walking relative to those unexposed. This did not differentially change the amount of overall physical activity or time spent walking compared to residents living farther away from the new LRT.

Keywords

Public Transit; Accelerometer Data; Built Environment; Behavior; Walking; Transportation; Neighborhood; Time; GPS