conference paper
Characterizing Freight Trucks using Advanced Technology-Based Methods
100th Transportation Research Board (TRB) Annual Meeting
Publication Date
January 1, 2021
Area of Expertise: Unspecified
conference paper
Functional modeling compiler for system-level design of automotive cyber-physical systems
2014 IEEE/ACM international conference on computer-aided design (ICCAD)
Publication Date
November 1, 2014
Author(s)
Arquimedes Canedo, Jiang Wan, Mohammad Al Faruque
Suggested Citation
Arquimedes Canedo, Jiang Wan and Mohammad Abdullah Al Faruque (2014) “Functional modeling compiler for system-level design of automotive cyber-physical systems”, in 2014 IEEE/ACM international conference on computer-aided design (ICCAD). IEEE, pp. 39–46. Available at: 10.1109/iccad.2014.7001327.
published journal article
Making decisions by D.V. Lindley - Review by L. Robin Keller
INTERFACES
Publication Date
January 1, 1987
Author(s)
LR Keller
Suggested Citation
LR Keller (1987) “Making decisions by D.V. Lindley - Review by L. Robin Keller”, INTERFACES, 17(1), pp. 135–137. published journal article
Metabolic dysfunction modifies the influence of traffic-related air pollution and noise exposure on late-life dementia and cognitive impairment: A cohort study of older Mexican-Americans
Environmental Epidemiology
Publication Date
December 1, 2020
Abstract
Background: Cognitive impairment has been linked to traffic-related air pollution and noise exposure as well as to metabolic syndrome or some of its individual components. Here, we investigate whether the presence of metabolic dysfunction modifies associations between air pollution or noise exposures and incident dementia or cognitive impairment without dementia (CIND). Methods: For 1,612 elderly Mexican-American participants of the Sacramento Area Latino Study on Aging (SALSA) followed for up to 10 years, we estimated residential-based local traffic-related exposures relying on the California Line Source Dispersion Model version 4 (CALINE4) for nitrogen oxides (NOx) and the SoundPLAN software package (Version 8.0; NAVCON, Fullerton, CA) that implements the Federal Highway Administration Traffic Noise Model (TNM) for noise, respectively. We used Cox proportional hazard models to estimate the joint effects of NOx or noise exposures and obesity, hyperglycemia, or low high-density lipoprotein (HDL) cholesterol. Results: The risk of developing dementia/CIND among participants with hyperglycemia who also were exposed to high levels of NOx (≥3.44 parts per billion [ppb] [75th percentile]) or noise (≥65 dB) was 2.4 (1.4, 4.0) and 2.2 (1.7, 3.9), respectively. For participants with low HDL-cholesterol, the estimated hazard ratios for dementia/CIND were 2.5 (1.4, 4.3) and 1.8 (1.0, 3.0) for those also exposed to high levels of NOx (≥3.44 ppb) or noise (≥65 dB), respectively, compared with those without metabolic dysfunction exposed to low traffic-related air pollution or noise levels. Conclusions: Exposure to traffic-related air pollution or noise most strongly increases the risk of dementia/CIND among older Mexican-Americans living in California who also exhibit hyperglycemia or low HDL-cholesterol.
Suggested Citation
Yu Yu, Mary Haan, Kimberly C. Paul, Elizabeth Rose Mayeda, Michael Jerrett, Jun Wu, Eunice Lee, Jason Su, I.-Fan Shih, Kosuke Inoue and Beate R. Ritz (2020) “Metabolic dysfunction modifies the influence of traffic-related air pollution and noise exposure on late-life dementia and cognitive impairment: A cohort study of older Mexican-Americans”, Environmental Epidemiology, 4(6), p. e122. Available at: 10.1097/EE9.0000000000000122. published journal article
Socioeconomic disparities and sexual dimorphism in neurotoxic effects of ambient fine particles on youth IQ: A longitudinal analysis
PLoS One
Publication Date
December 1, 2017
Author(s)
Pan Wang, Catherine Tuvblad, Diana Younan, Meredith Franklin, Fred Lurmann, Jun Wu, Laura A. Baker, Jiu-Chiuan Chen
Abstract
Mounting evidence indicates that early-life exposure to particulate air pollutants pose threats to children’s cognitive development, but studies about the neurotoxic effects associated with exposures during adolescence remain unclear. We examined whether exposure to ambient fine particles (PM2.5) at residential locations affects intelligence quotient (IQ) during pre-/early- adolescence (ages 9-11) and emerging adulthood (ages 18-20) in a demographicallydiverse population (N = 1,360) residing in Southern California. Increased ambient PM2.5 levels were associated with decreased IQ scores. This association was more evident for Performance IQ (PIQ), but less for Verbal IQ, assessed by the Wechsler Abbreviated Scale of Intelligence. For each inter-quartile (7.73 mu g/m(3)) increase in one-year PM2.5 preceding each assessment, the average PIQ score decreased by 3.08 points (95% confidence interval = [-6.04, -0.12]) accounting for within-family/within-individual correlations, demographic characteristics, family socioeconomic status (SES), parents’ cognitive abilities, neighborhood characteristics, and other spatial confounders. The adverse effect was 150% greater in low SES families and 89% stronger in males, compared to their counterparts. Better understanding of the social disparities and sexual dimorphism in the adverse PM2.5-IQ effects may help elucidate the underlying mechanisms and shed light on prevention strategies.
Suggested Citation
Pan Wang, Catherine Tuvblad, Diana Younan, Meredith Franklin, Fred Lurmann, Jun Wu, Laura A. Baker and Jiu-Chiuan Chen (2017) “Socioeconomic disparities and sexual dimorphism in neurotoxic effects of ambient fine particles on youth IQ: A longitudinal analysis”, PLoS One, 12(12), p. e0188731. Available at: 10.1371/journal.pone.0188731. published journal article
An Integrated Analysis of Complex Travel Behavior and Urban Form Indicators
Urban Geography
Publication Date
April 1, 1982
Author(s)
Will Recker, Harry J. Schuler
Suggested Citation
Wilfred W. Recker and Harry J. Schuler (1982) “An Integrated Analysis of Complex Travel Behavior and Urban Form Indicators”, Urban Geography, 3(2), pp. 110–120. Available at: 10.2747/0272-3638.3.2.110. published journal article
Fare determination in airline hub-and-spoke networks
The RAND Journal of Economics
Publication Date
January 1, 1992
Author(s)
Jan Brueckner, Nichola J. Dyer, Pablo T. Spiller
Abstract
This article provides the first evidence linking airfares to the structure of airline hub-and-spoke networks. The hypothesis tested is that any force that increases traffic volume on the spokes of a network will reduce fares in the markets it serves. This effect arises because of economies of density on the spokes. For example, since a large network (as measured by the number of city pairs that it connects) is expected to have low costs per passenger as a result of high traffic densities, fares in the individual markets served should be low, other things equal. Similarly, holding size fixed, a network that connects large cities should have higher traffic densities on its spokes (and thus lower fares in individual markets) than one serving small cities. Our empirical analysis supports these predictions. We find that network characteristics are important determinants of fares in 4-segment city-pair markets (these are markets requiring a connection at the hub). Furthermore, our empirical model predicts that the TWA-Ozark and Northwest-Republic mergers should have reduced fares in the 4-segment markets served by the hubs at St. Louis and Minneapolis.
Suggested Citation
Jan K. Brueckner, Nichola J. Dyer and Pablo T. Spiller (1992) “Fare determination in airline hub-and-spoke networks”, The RAND Journal of Economics, 23(3), p. 309. Available at: 10.2307/2555865. working paper
The Use of Alternative Specific Constants in Choice Modeling
Publication Date
December 1, 1978
Author(s)
Working Paper
UCI-ITS-WP-78-11
Abstract
A specification issue which has been handled differently in various empirical applications is whether or not to include alternative specific constants in models of choice behavior. Some applications have excluded constants, others have included a full set of constants, and a third class of examples uses unique constants for some alternatives, but not all. In logit models in which each individual has the same set of alterna tives, the exclusion of constants in the estimation of models when the correct model actually has alternative specific effects leads to inconsistent estimates of the coefficients of the remaining independent variables. However, the inclusion of constants when no such effects exist does not affect the consistency of the estimates of the coefficients. These results are illustrated by simple hypothetical examples and by empirical examples. When nonratio scale variables are used in logit models, the coefficients of the independent variables are not invariant under arbitrary scale shifts when alternative specific constants are excluded. Finally, the use of models to predict the response to new alternatives and the transferability of models which might or might not include alternative specific effects is discussed. The major conclusion is that the inclusion of: a full set of alternative specific constants in logit models estimated with large samples is generally preferred over the exclusion of one or more alternative specific constants.
Suggested Citation
Timothy J. Tardiff (1978) The Use of Alternative Specific Constants in Choice Modeling. Working Paper UCI-ITS-WP-78-11. Institute of Transportation Studies, Irvine. Available at: https://escholarship.org/uc/item/5j43q8mj. published journal article
Corrigendum to “Exposure to air pollutant mixture and gestational diabetes mellitus in Southern California: Results from electronic health record data of a large pregnancy Cohort” [Environ. Int. 158 (2022) 106888]
Environment International
Publication Date
May 1, 2022
Author(s)
Yi Sun, Xia Li, Tarik Benmarhnia, Jiu-Chiuan Chen, Chantal Avila, David A. Sacks, Vicki Chiu, Jeff Slezak, John Molitor, Darios Getahun, Jun Wu
Suggested Citation
Yi Sun, Xia Li, Tarik Benmarhnia, Jiu-Chiuan Chen, Chantal Avila, David A. Sacks, Vicki Chiu, Jeff Slezak, John Molitor, Darios Getahun and Jun Wu (2022) “Corrigendum to “Exposure to air pollutant mixture and gestational diabetes mellitus in Southern California: Results from electronic health record data of a large pregnancy Cohort” [Environ. Int. 158 (2022) 106888]”, Environment International, 163, p. 107207. Available at: 10.1016/j.envint.2022.107207. published journal article
Continuum car-following model of capacity drop at sag and tunnel bottlenecks
Transportation Research Part C: Emerging Technologies
Publication Date
April 1, 2020
Author(s)
Kentaro Wada, Irene Martinez, Wenlong Jin
Abstract
Sags and tunnels are major bottlenecks, where the road capacity is reduced, and the “capacity drop” phenomenon occurs; however, there is no simple model or theory that can explain the formation and other characteristics of capacity drop. This paper presents a car-following model, which is equivalent to a continuum model in the Lagrangian coordinates. The model is built on two main assumptions: (i) inhomogeneous fundamental diagrams with location-dependent time gaps, and (ii) bounded acceleration. We first demonstrate that the stationary speed profiles, the low acceleration rates, the dropped capacity, and the approximate time duration of the capacity drop formation in the model are consistent with empirical observations. Then the impacts on the stationary states and dropped capacity of the numerical viscosity caused by the discretization method are investigated, and it is shown that the dropped capacity converges to the theoretical value. Further, a one-dimensional iterated function system is proposed to model the formation mechanism of the capacity drop, which is derived by investigating the spatial pattern of equilibrium and bounded acceleration traffic states that arises in a lead-vehicle problem. Utilizing this model, we uncover a set of properties of the capacity drop such as existence, uniqueness, global convergence, and convergence speed. Finally, the model is applied to analyze the impacts of heterogeneous drivers. The model and insights in this study will help to develop control and management schemes to alleviate capacity drop effects with connected and autonomous vehicles in the future.