published journal article
State affordable housing appeals systems and access to opportunity: Evidence from the northeastern united states
Housing Policy Debate
Publication Date
March 1, 2020
Area of Expertise: Unspecified
published journal article
A review of California’s process for determining, and accommodating, regional housing needs
Background Paper Prepared for the California State Auditor in Rlation to the Audit Ordered by the Joint Legislative Audit Committee on Oct. 11
Publication Date
January 1, 2021
Author(s)
Christopher S. Elmendorf, Nicholas Marantz, Paavo Monkkonen
Suggested Citation
Christopher S. Elmendorf, Nicholas Marantz and Paavo Monkkonen (2021) “A review of California’s process for determining, and accommodating, regional housing needs”, Background Paper Prepared for the California State Auditor in Rlation to the Audit Ordered by the Joint Legislative Audit Committee on Oct. 11 [Preprint]. Available at: https://law.ucdavis.edu/sites/g/files/dgvnsk10866/files/inline-files/RHNA-Audit-Background-Paper-2021.01.04.pdf (Accessed: August 21, 2025). published journal article
Indoor-Generated PM2.5 During COVID-19 Shutdowns Across California: Application of the PurpleAir Indoor–Outdoor Low-Cost Sensor Network
Environmental Science & Technology
Publication Date
May 4, 2021
Author(s)
Amirhosein Mousavi, Jun Wu
Abstract
Although evidences showed an overall reduction in outdoor air pollution levels across the globe due to COVID-19-related lockdown, no comprehensive assessment was available for indoor air quality during the period of stay-at-home orders, despite that the residential indoor environment contributes most to personal exposures. We examined temporal and diurnal variations of indoor PM2.5 based on real-time measurements from 139 indoor–outdoor co-located low-cost PurpleAir sensor sets across California for pre-, during, and post-lockdown periods in 2020 and “business-as-usual” periods in 2019. A two-step method was implemented to systematically control the quality of raw sensor data and calibrate the sensor data against co-located reference instruments. During the lockdown period, 17–24% higher indoor PM2.5 concentrations were observed in comparison to those in the 2019 business-as-usual period. In residential sites, a clear peak in PM2.5 concentrations in the afternoon and elevated evening levels toping at roughly 10 μg·m–3 was observed, which reflects enhanced human activity during lunch and dinner time (i.e., cooking) and possibly more cleaning and indoor movement that increase particle generation and resuspension in homes. The contribution of indoor-generated PM2.5 to total indoor concentrations increased as high as 80% during and post-lockdown periods compared to before lockdown.
Suggested Citation
Amirhosein Mousavi and Jun Wu (2021) “Indoor-Generated PM2.5 During COVID-19 Shutdowns Across California: Application of the PurpleAir Indoor–Outdoor Low-Cost Sensor Network”, Environmental Science & Technology, 55(9), pp. 5648–5656. Available at: 10.1021/acs.est.0c06937.
conference paper
Development of an adaptive origin-destination estimation methodology considering traffic operational characteristics
ICTE 2011
Publication Date
July 1, 2011
Author(s)
Xiaobo Liu, Lianyu Chu, Mei Chen
Suggested Citation
Xiaobo Liu, Lianyu Chu and Mei Chen (2011) “Development of an adaptive origin-destination estimation methodology considering traffic operational characteristics”, in ICTE 2011. American Society of Civil Engineers, pp. 364–369. Available at: 10.1061/41184(419)61. published journal article
Gradient projection method for simulation-based dynamic traffic assignment
Transportation Research Record
Publication Date
January 1, 2012
Author(s)
Suggested Citation
Inchul Yang and R. Jayakrishnan (2012) “Gradient projection method for simulation-based dynamic traffic assignment”, Transportation Research Record, 2284(1), pp. 70–80. Available at: 10.3141/2284-09. published journal article
A theory of urban squatting and land-tenure formalization in developing countries
American Economic Journal: Economic Policy
Publication Date
January 1, 2009
Author(s)
Jan Brueckner, Harris Selod
Abstract
This paper offers a new theoretical approach to urban squatting, reflecting the view that squatters and formal residents compete for land within a city. The key implication is that squatters “squeeze” the formal market, raising the price paid by formal residents. The squatter organizer ensures that squeezing is not too severe, since otherwise, the formal price will rise to a level that invites eviction by landowners. Because eviction is absent in equilibrium, the model differs from previous analytical frameworks, where eviction occurs with some probability. It also facilitates a general equilibrium analysis of squatter formalization policies. (JEL O15, Q15, R14)
Suggested Citation
Jan K Brueckner and Harris Selod (2009) “A theory of urban squatting and land-tenure formalization in developing countries”, American Economic Journal: Economic Policy, 1(1), pp. 28–51. Available at: 10.1257/pol.1.1.28. conference paper
Architecture integrating symbolic and connectionist models for traffic management center decision support
Proceedings of the international conference on applications of advanced technologies in transportation engineering
Publication Date
January 1, 1996
Author(s)
Martin Molina, Filippo Logi, Stephen Ritchie, Jose Cuena
Suggested Citation
Martin Molina, Filippo Logi, Stephen G. Ritchie and Jose Cuena (1996) “Architecture integrating symbolic and connectionist models for traffic management center decision support”, in Proceedings of the international conference on applications of advanced technologies in transportation engineering, pp. 320–324. published journal article
Refining time-activity classification of human subjects using the global positioning system
PLoS One
Publication Date
February 1, 2016
Author(s)
Abstract
Background Detailed spatial location information is important in accurately estimating personal exposure to air pollution. Global Position System (GPS) has been widely used in tracking personal paths and activities. Previous researchers have developed time-activity classification models based on GPS data, most of them were developed for specific regions. An adaptive model for time-location classification can be widely applied to air pollution studies that use GPS to track individual level time-activity patterns. Methods Time-activity data were collected for seven days using GPS loggers and accelerometers from thirteen adult participants from Southern California under free living conditions. We developed an automated model based on random forests to classify major time-activity patterns (i.e. indoor, outdoor-static, outdoor-walking, and in-vehicle travel). Sensitivity analysis was conducted to examine the contribution of the accelerometer data and the supplemental spatial data (i.e. roadway and tax parcel data) to the accuracy of time-activity classification. Our model was evaluated using both leave-one-fold-out and leave-one-subject-out methods. Results Maximum speeds in averaging time intervals of 7 and 5 minutes, and distance to primary highways with limited access were found to be the three most important variables in the classification model. Leave-one-fold-out cross-validation showed an overall accuracy of 99.71%. Sensitivities varied from 84.62% (outdoor walking) to 99.90% (indoor). Specificities varied from 96.33% (indoor) to 99.98% (outdoor static). The exclusion of accelerometer and ambient light sensor variables caused a slight loss in sensitivity for outdoor walking, but little loss in overall accuracy. However, leave-one-subject-out cross-validation showed considerable loss in sensitivity for outdoor static and outdoor walking conditions. Conclusions The random forests classification model can achieve high accuracy for the four major time-activity categories. The model also performed well with just GPS, road and tax parcel data. However, caution is warranted when generalizing the model developed from a small number of subjects to other populations.
Suggested Citation
Maogui Hu, Wei Li, Lianfa Li, Douglas Houston and Jun Wu (2016) “Refining time-activity classification of human subjects using the global positioning system”, PLoS One, 11(2), p. e0148875. Available at: 10.1371/journal.pone.0148875. published journal article
A model of complex travel behavior: Part II—An operational model
Transportation Research Part A: General
Publication Date
July 1, 1986
Author(s)
Abstract
Based on the theoretical model of complex travel behavior developed in a companion paper (Recker et al., 1986), an operational system of models, STARCHILD (Simulation of Travel/Activity Responses to Complex Household Interactive Logistic Decisions), has been developed to examine the formation of household travel/activity patterns. The system employs a simulation approach in combination with techniques of pattern recognition, multiobjective optimization and disaggregate choice models. Initial empirical verification of the system of models is presented based on results obtained from a sample data set.
Suggested Citation
W. W. Recker, M. G. McNally and G. S. Root (1986) “A model of complex travel behavior: Part II—An operational model”, Transportation Research Part A: General, 20(4), pp. 319–330. Available at: 10.1016/0191-2607(86)90090-7. book/book chapter
Freight-transportation externalities
Publication Date
January 1, 2011
Author(s)
Fatemeh Ranaiefar, Regan Amelia