research report
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published journal article
Real-time inductive-signature-based level of service for signalized intersections
Transportation Research Record
Publication Date
Author(s)
Suggested Citation
Cheol Oh and Stephen G. Ritchie (2002) “Real-time inductive-signature-based level of service for signalized intersections”, Transportation Research Record, 1802(1), pp. 97–104. Available at: 10.3141/1802-12.published journal article
Short-Term Exposure to Ambient Air Pollution and Increased Emergency Room Visits for Skin Diseases in Beijing, China
Toxics
Publication Date
Author(s)
Abstract
Skin diseases have become a global concern. This study aims to evaluate the associations between ambient air pollution and emergency room visits for skin diseases under the background of improving air quality in China. Based on 45,094 cases from a general hospital and fixed-site monitoring environmental data from 2014–2019 in Beijing, China, this study used generalized additive models with quasi-Poisson regression to estimate the exposure–health associations at lag 0–1 to lag 0–7. PM2.5 and NO2 exposure were associated with increased emergency room visits for total skin diseases (ICD10: L00-L99). Positive associations of PM2.5, PM10, O3 and NO2 with dermatitis/eczema (ICD-10: L20–30), as well as SO2 and NO2 with urticaria (ICD-10: L50) visits were also found. For instance, a 10 μg/m3 increase in PM2.5 was associated with increases of 0.7% (95%CI: 0.2%, 1.2%) in total skin diseases visits at lag 0–5 and 1.1% (95%CI: 0.6%, 1.7%) in dermatitis/eczema visits at lag 0–1, respectively. For PM2.5, PM10 and CO, stronger annual associations were typically observed in the high-pollution (2014) and low-pollution (2018/2019) years. For instance, a 10 μg/m3 increase in PM2.5 at lag 0–5 was associated with increases of 1.8% (95%CI: 1.0%, 2.6%) and 2.3% (95%CI: 0.4%, 4.3%) in total skin disease visits in 2014 and 2018, respectively. Our study emphasizes the necessity of controlling the potential health hazard of air pollutants on skin, although significant achievements in air quality control have been made in China.
Suggested Citation
Wanzhou Wang, Wenlou Zhang, Jingjing Zhao, Hongyu Li, Jun Wu, Furong Deng, Qingbian Ma and Xinbiao Guo (2021) “Short-Term Exposure to Ambient Air Pollution and Increased Emergency Room Visits for Skin Diseases in Beijing, China”, Toxics, 9(5), p. 108. Available at: 10.3390/toxics9050108.published journal article
Cyber-physical codesign at the functional level for multidomain automotive systems
IEEE SYSTEMS JOURNAL
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Author(s)
Abstract
Software-integrated multidomain automotive systems, which is also referred to as automotive cyber-physical systems (CPS) consist of various interacting domains (software, hardware, multiphysics, communication, etc.). Design decisions in one domain may completely change the constraints and requirements in the other domains, e.g., adding more functions in a modern automotive CPS may require changes to thousands of lines of software code or even the mechanical architecture. Existing CPS design methodologies are siloed in a specific domain and therefore have limited design space exploration capabilities because only one domain can be tested at a time. This paper presents a functional-level cyber-physical codesign methodology starting from the functional model of the CPS capable of concurrently expressing (multi-)physics and control in automotive applications. Moreover, we introduce a high-level synthesis algorithm capable of selecting a set of optimized system architectures using various executable simulation components and cost metrics. We demonstrate our methodology with a realistic automotive use case and explore various design alternatives for implementing the control systems in pure continuous domain (e.g., traditional automotive subsystems without engine control units) or hybrid domain (e.g., brake-by-wire, steer-by-wire, drive-by-wire, etc.) under power, performance, and reliability constraints.
Suggested Citation
Jiang Wan, Arquimedes Canedo and Mohammad Abdullah Al Faruque (2017) “Cyber-physical codesign at the functional level for multidomain automotive systems”, IEEE SYSTEMS JOURNAL, 11(4), pp. 2949–2959. Available at: 10.1109/JSYST.2015.2472495.published journal article
A Link Queue Model of Network Traffic Flow
Transportation Science
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Author(s)
Abstract
Fundamental to many transportation network studies, traffic flow models can be used to describe traffic dynamics determined by drivers’ car-following, lane-changing, merging, and diverging behaviors. In this study, we develop a deterministic queueing model of network traffic flow, in which traffic on each link is considered as a queue. In the link queue model (LQM), the demand and supply of a link queue are defined in the queue size (number of vehicles), and its in- and out-flows are computed from junction flux functions corresponding to macroscopic merging and diverging rules. The new model is a system of ordinary differential equations that is mathematically tractable and computationally efficient and can capture queue spillbacks and interactions among links. We further demonstrate that the LQM is fundamentally different from the cell transmission model (CTM) and link transmission model (LTM) for a road segment, a signalized ring road, and a diverge-merge network, with respect to the shock and rarefaction waves, network fundamental diagram, and stability property. In a sense, the new model is a space-continuous approximation of the kinematic wave model and can be a useful addition to the multiscale modeling framework of network traffic flow. The model has been applied to formulate and solve network traffic control and observation problems.
Suggested Citation
Wen-Long Jin (2021) “A Link Queue Model of Network Traffic Flow”, Transportation Science, 55(2), pp. 436–455. Available at: 10.1287/trsc.2020.1012.conference paper
Set Cover-based Formulation and Decomposition Solution Approach for the Crowdsourced Package Delivery Problem
100th Transportation Research Board (TRB) Annual Meeting
Publication Date
Author(s)
Suggested Citation
Dingtong Yang, Michael F. Hyland and R. Jayakrishnan (2021) “Set Cover-based Formulation and Decomposition Solution Approach for the Crowdsourced Package Delivery Problem”. 100th Transportation Research Board (TRB) Annual Meeting, Washington, DC.published journal article
Did the 65 mph speed limit save lives?
Accident Analysis & Prevention
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Author(s)
Suggested Citation
Charles Lave and Patrick Elias (1994) “Did the 65 mph speed limit save lives?”, Accident Analysis & Prevention, 26(1), pp. 49–62. Available at: 10.1016/0001-4575(94)90068-X.working paper
Competition and Prices in the Deregulated Gas Pipeline Network: A Multivariate Cointegration Analysis
Publication Date
Associated Project
Author(s)
Abstract
This research uses multivariate cointegration analysis to assess the degree of competition in the U.S. natural gas industry following the move to open access pipeline transportation. The testing methodology allows multiple nodes in the pipeline network to be analyzed simultaneously and is based on recent advances by Johansen (1988, 1991) and Johansen and Juselius (1990) on estimation and hypothesis testing in multivariate cointegrated systems. Daily price data across the North American natural gas transmission grid are analyzed and the results indicate that the pattern of prices between production areas is consistent with allocative efficiency.
Suggested Citation
W. David Walls (1993) Competition and Prices in the Deregulated Gas Pipeline Network: A Multivariate Cointegration Analysis. Working Paper No. 203. Institute of Transportation Studies, UC Irvine: University of California Transportation Center. Available at: https://escholarship.org/uc/item/9tg8v7zd.research report
Evaluation of Signalized Intersection Safety Using Centracs System
Publication Date
Associated Project
Author(s)
Final Report
Areas of Expertise
Suggested Citation
Xinkai Wu, Sawanpreet Dhaliwal, Will Recker, Wenlong Jin and Xudong Jia (2016) Evaluation of Signalized Intersection Safety Using Centracs System. Final Report CA17-2646. Caltrans / CalPoly Pomona / ITS-Irvine. Available at: https://dot.ca.gov/-/media/dot-media/programs/research-innovation-system-information/documents/final-reports/ca17-2646-finalreport-a11y.pdf.published journal article
Intention–Behavior Discrepancy of Foreign versus Domestic Brands in Emerging Markets: The Relevance of Consumer Prior Knowledge
Journal of International Marketing
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Author(s)
Abstract
Most research on the performance of foreign versus domestic brands in emerging markets has examined dependent measures of product evaluation or purchase intention. However, consumers who intend to buy a product may switch to competing brands, thus displaying an intention–behavior discrepancy (IBD). Drawing on literature on country associations and dual process theory, the authors examine the performance of foreign versus domestic brands on IBD in emerging markets and the moderating role of consumer prior knowledge. They conduct an intention survey followed by a postpurchase survey in the Chinese automobile and smartphone industries and find that foreign brands have an advantage on IBD relative to domestic brands, indicating that they have the dual advantage of higher evaluations and lower IBDs. Furthermore, foreign brands’ advantage on IBD is smaller for consumers with inaccurate prior knowledge because they are more likely to systematically reprocess information and discount foreign brands’ favorable country associations. For these consumers, overestimating the product reduces foreign brands’ advantage to a lesser degree than underestimating it as a result of confirmation bias. These findings provide implications for brands in emerging markets.