conference paper

New inductive signature data compression and transformation method for online vehicle reidentification

Proceedings of the 85th annual meeting of the transportation research board

Publication Date

January 1, 2006

Abstract

Traffic operations field computational resources as well as the bandwidth of field communication links are often quite limited. Accordingly, for on-line implementation of Advanced Transportation Management and Information Systems (ATMIS) strategies, such as vehicle reidentification, there is strong interest in development of fieldâ??based techniques and models that can perform satisfactorily while minimizing field computational and communication requirements. A new vehicle reidentification algorithm (REID-2) developed previously by the authors (1) was oriented toward algorithm simplification, but also demonstrated the added benefits of improved performance and much broader potential applicability (to both round and square single inductive loops) compared with earlier methods. However, the basis of REID-2 is directly matching inductive vehicle signatures, which typically consist of 200~1,200 data points (stored as integers, and obtained from IST-222 detector cards) per signature. The purpose of this research was to investigate if a relatively simple data compression and transformation technique could be applied successfully to the raw inductive signatures for each vehicle, and then use the resulting transformed vehicle signatures as inputs to vehicle reidentification. A Piecewise Slope Rate (PSR) approach was used to compress and transform the raw vehicle signatures. The results of this investigation, including sensitivity analyses, vehicle reidentification performance, and the accuracy of section travel time measurement, are very promising and suggest that the reduction in both computational effort and computer memory needed to store individual signatures with this approach could potentially benefit both the field computational and communication requirements needed for real-time implementation of this modified vehicle reidentification technique.

Suggested Citation
Shin-Ting (Cindy) Jeng and Stephen G. Ritchie (2006) “New inductive signature data compression and transformation method for online vehicle reidentification”, in Proceedings of the 85th annual meeting of the transportation research board, p. 26p.

working paper

A Dynamic Analysis of Travel Demand

Publication Date

December 1, 1985

Author(s)

Working Paper

UCI-ITS-WP-85-11

Areas of Expertise

Abstract

A panel data set is analysed with the goal of identifying patterns of change in the use of various modes of transport. The data set, which represents a national sample of the Netherlands, is comprised of over 2000 individuals surveyed in three waves six months apart in 1984 and 1985. The data were processed in the form of categorical variables depicting use or non-use of each mode at each wave and were analysed using log-linear models. Results indicated that there were significant patterns of change for all of the modes studied. Some of these patterns were interpreted as representing seasonality, while others were interpreted as representing more fundamental adjustments in travel behavior.

Suggested Citation
Thomas F. Golob, Leo van Wissen and Henk Meurs (1985) A Dynamic Analysis of Travel Demand. Working Paper UCI-ITS-WP-85-11. Institute of Transportation Studies, Irvine. Available at: https://escholarship.org/uc/item/6464x49x.

conference paper

Vehicle reidentification with the inductive loop signature technology

Proceedings of the 10th international conference of eastern asia society for transportation studies (EASTS), taipei, taiwan

Publication Date

September 1, 2013
Suggested Citation
S-T. Jeng and L. Chu (2013) “Vehicle reidentification with the inductive loop signature technology”, in Proceedings of the 10th international conference of eastern asia society for transportation studies (EASTS), taipei, taiwan.

published journal article

Local truckload pickup and delivery with hard time window constraints

Transportation Research Part B: Methodological

Publication Date

February 1, 2002
Suggested Citation
Xiubin Wang and Amelia C. Regan (2002) “Local truckload pickup and delivery with hard time window constraints”, Transportation Research Part B: Methodological, 36(2), pp. 97–112. Available at: 10.1016/s0965-8564(00)00037-9.

published journal article

Environmental uncertainty and the timing of environmental policy

Natural Resource Modeling

Publication Date

June 1, 2008
Suggested Citation
Jean-Daniel M. Saphores (2008) “Environmental uncertainty and the timing of environmental policy”, Natural Resource Modeling, 17(2), pp. 163–190. Available at: 10.1111/j.1939-7445.2004.tb00132.x.

published journal article

Fine Particulate Matter, Its Constituents, and Spontaneous Preterm Birth

JAMA Network Open

Publication Date

November 13, 2024

Author(s)

Anqi Jiao, Alexa N. Reilly, Tarik Benmarhnia, Yi Sun, Chantal Avila, Vicki Chiu, Jeff Slezak, David A. Sacks, John Molitor, Mengyi Li, Jiu-Chiuan Chen, Jun Wu, Darios Getahun

Abstract

The associations of exposure to fine particulate matter (PM2.5) and its constituents with spontaneous preterm birth (sPTB) remain understudied. Identifying subpopulations at increased risk characterized by socioeconomic status and other environmental factors is critical for targeted interventions.To examine associations of PM2.5 and its constituents with sPTB.This population-based retrospective cohort study was conducted from 2008 to 2018 within a large integrated health care system, Kaiser Permanente Southern California. Singleton live births with recorded residential information of pregnant individuals during pregnancy were included. Data were analyzed from December 2023 to March 2024.Daily total PM2.5 concentrations and monthly data on 5 PM2.5 constituents (sulfate, nitrate, ammonium, organic matter, and black carbon) in California were assessed, and mean exposures to these pollutants during pregnancy and by trimester were calculated. Exposures to total green space, trees, low-lying vegetation, and grass were estimated using street view images. Wildfire-related exposure was measured by the mean concentration of wildfire-specific PM2.5 during pregnancy. Additionally, the mean exposure to daily maximum temperature during pregnancy was calculated.The primary outcome was sPTB identified through a natural language processing algorithm. Discrete-time survival models were used to estimate associations of total PM2.5 concentration and its 5 constituents with sPTB. Interaction terms were used to examine the effect modification by race and ethnicity, educational attainment, household income, and exposures to green space, wildfire smoke, and temperature.Among 409 037 births (mean [SD] age of mothers at delivery, 30.3 [5.8] years), there were positive associations of PM2.5, black carbon, nitrate, and sulfate with sPTB. Adjusted odds ratios (aORs) per IQR increase were 1.15 (95% CI, 1.12-1.18; P < .001) for PM2.5 (IQR, 2.76 μg/m3), 1.15 (95% CI, 1.11-1.20; P < .001) for black carbon (IQR, 1.05 μg/m3), 1.09 (95% CI, 1.06-1.13; P < .001) for nitrate (IQR, 0.93 μg/m3), and 1.06 (95% CI, 1.03-1.09; P < .001) for sulfate (IQR, 0.40 μg/m3) over the entire pregnancy. The second trimester was the most susceptible window; for example, aORs for total PM2.5 concentration were 1.07 (95% CI, 1.05-1.09; P < .001) in the first, 1.10 (95% CI, 1.08-1.12; P < .001) in the second, and 1.09 (95% CI, 1.07-1.11; P < .001) in the third trimester. Significantly higher aORs were observed among individuals with lower educational attainment (eg, less than college: aOR, 1.16; 95% CI, 1.12-1.21 vs college [≥4 years]: aOR, 1.10; 95% CI, 1.06-1.14; P = .03) or income (<50th percentile: aOR, 1.17; 95% CI, 1.14-1.21 vs ≥50th percentile: aOR, 1.12; 95% CI, 1.09-1.16; P = .02) or who were exposed to limited green space (<50th percentile: aOR, 1.19; 95% CI, 1.15-1.23 vs ≥50th percentile: aOR, 1.12; 95% CI, 1.09-1.15; P = .003), more wildfire smoke (≥50th percentile: aOR, 1.19; 95% CI, 1.16-1.23 vs <50th percentile: aOR, 1.13; 95% CI, 1.09-1.16; P = .009), or extreme heat (aOR, 1.51; 95% CI, 1.42-1.59 vs mild temperature: aOR, 1.11; 95% CI, 1.09-1.14; P < .001).In this study, exposures to PM2.5 and specific PM2.5 constituents during pregnancy were associated with increased odds of sPTB. Socioeconomic status and other environmental exposures modified this association.

Suggested Citation
Anqi Jiao, Alexa N. Reilly, Tarik Benmarhnia, Yi Sun, Chantal Avila, Vicki Chiu, Jeff Slezak, David A. Sacks, John Molitor, Mengyi Li, Jiu-Chiuan Chen, Jun Wu and Darios Getahun (2024) “Fine Particulate Matter, Its Constituents, and Spontaneous Preterm Birth”, JAMA Network Open, 7(11), p. e2444593. Available at: 10.1001/jamanetworkopen.2024.44593.

working paper

Companionship and Altruism in Daily Activity Time Allocation and Travel by Men and Women in the Same Households

Publication Date

January 1, 2007

Author(s)

Konstadinos Goulias

Abstract

In this paper, using data from 366 households we study human interaction within and outside the household. In the analysis altruism and companionship between men and women are explored using path analysis to identify gender-roles and mutual influences. Men and women have very different templates of time allocation characterized by lack of symmetry in relationships between men and women. Although women’s time allocation has some influence on men’s time allocation, it may function as a constraint only when women engage in activities for a considerable amount of time in a day. In contrast, men’s influence is significant and substantial at any level of time allocation. Regarding the relationship between altruism and companionship, men appear to be “rationing” their time and allocate time either to relatives or to others. Women appear to be more fully engaged with relatives and with others (presumably functioning as the social network hubs of the household). Finally, travel is not emerging as a cause but as an outcome supporting once again the practice in activity-based models of considering travel demand as derived from the need to participate in activities. It should also be noted that travel is a very small fraction of the total daily time allocation and does not function as a constraint in budgeting time for activities with and for relatives and other persons. A clear hierarchy also emerges from the path model developed here with blocks of variables determining other blocks of variables in a sequence.

published journal article

A conceptual framework for multiple stakeholder educational decision making

International Journal of Education Policy and Leadership

Publication Date

September 1, 2006

Author(s)

S. David Brazer, Robin Keller
Suggested Citation
S. David Brazer and L. Robin Keller (2006) “A conceptual framework for multiple stakeholder educational decision making”, International Journal of Education Policy and Leadership, 1(3), pp. 1–14.

published journal article

Simulation framework for modeling large-scale flexible transit systems

Transportation Research Record

Publication Date

January 1, 2014
Suggested Citation
Jaeyoung Jung and R. Jayakrishnan (2014) “Simulation framework for modeling large-scale flexible transit systems”, Transportation Research Record, 2466(1), pp. 31–41. Available at: 10.3141/2466-04.

published journal article

Design and Operational Concepts of High-Coverage Point-to-Point Transit System

Transportation Research Record: Journal of the Transportation Research Board

Abstract

Conceptual design and preliminary feasibility simulation results are presented for a flexible transit system for travel from any point to any point based on real-time personalized travel desires, which is now possible because of advances in communications and computing technologies. Although it is demand-responsive, the concept is significantly different from older demand-responsive transit systems, which were often failures. The proposed system requires high coverage, referring to the availability of a large number of transit vehicles (often minibuses or vans), which could also operate in conjunction with private transit and paratransit systems. The design strictly eliminates more than one transfer for any passenger. The system could potentially provide a transit alternative that is much more competitive with personal automobile travel than are conventional transit systems because of significantly lower waiting times. The passenger demand for such a system is uncertain, but preliminary simulations show that under a variety of acceptable demand levels, the system can operate with high cost-effectiveness. The focus is on describing the details of the concept and providing arguments in favor of the system based on simulations. The system essentially attempts to solve a stochastic real-time passenger pickup-and-delivery problem with a large number of vehicles. A strict optimization formulation and solution for such a problem are computationally prohibitive in real time. The design proposed is effectively geared toward a decomposed solution using detailed rules that achieve vehicle selection and route planning. If real-time update of probabilities is included, this scheme could be considered as a form of quasi-optimal stochastic control.

Suggested Citation
Cristián E. Cortés and R. Jayakrishnan (2002) “Design and Operational Concepts of High-Coverage Point-to-Point Transit System”, Transportation Research Record: Journal of the Transportation Research Board, 1783(1), pp. 178–187. Available at: 10.3141/1783-22.