21 research outputs found
Understanding preferences for autonomous trucks functions in China: Insights from drivers and organizational buyers
No full textThe transportation industry is undergoing a significant transformation as it integrates advanced driver assistance systems (ADAS) technologies. This shift is particularly important in the trucking industry. Driver assistance technologies offer a promising solution for improving safety and reducing traffic accidents. However, the trucking industry lags significantly behind passenger vehicles in the maturity and penetration rate of such technologies. This study uses a stated preference survey to explore the purchasing preferences for ADAS functions among truck drivers and organization buyers in China. Our findings show that truck drivers with a safe driving history prioritize reliability and assistance features such as automatic emergency braking, adaptive cruise control, and lane-centering control. In contrast, drivers with a record of unsafe driving favor more advanced ADAS functions, such as city or highway navigation on autopilot, owing to their ability to alleviate driving stress. Buyers from organizations, compared with individual truck drivers, are more averse to the additional costs of ADAS technologies, while larger companies seem more willing to invest in autonomous trucks than are smaller businesses and individuals. However, top management teams remain cautious, reflecting a lack of confidence in the operational and safety benefits of the current technology at Level 2 autonomy. Resistance to adopting autonomous trucks is also stronger among male (vs. female) drivers and older drivers, who comprise a large segment of the domestic market. The study recommends that autonomous vehicle system providers and governments prioritize active safety functions to further improve safety. Furthermore, it is suggested that extensive training and trials be provided to increase trust and confidence in autonomous truck technologies among industry stakeholders.
What Patterns Contribute to Autonomous Vehicle Crashes? A Study of Level 2 and 4 Automation via Association Rule Analysis
No full textWith increasing autonomous vehicle (AV) penetration, understanding the factors contributing to AV crashes is crucial for addressing ongoing road safety challenges. This study aims to reveal the effects of vehicle characteristics, road conditions, environmental factors, and precrash movements on the occurrence of head-on, rear-end, and side-impact crashes. In particular, factors associated with various types of Level 2 and Level 4 AV crashes were analyzed. Our data, obtained from the California Department of Motor Vehicles and the National Highway Traffic Safety Administration, spans from October 2014 to March 2024. Association rule mining techniques identify the significant patterns and interdependencies among the factors contributing to AV crashes. The findings demonstrate that the factors influencing crash types include weather, roadway surface, lighting, and vehicle precrash movements. For example, head-on crashes frequently occur at intersections under poor lighting conditions, whereas rear-end crashes occur more frequently on high-speed highways, particularly because of unexpected braking by the vehicle ahead. Side-impact crashes commonly result from merging maneuvers, especially under adverse weather and lighting conditions. These findings provide new insights into the causal mechanisms behind different types of AV crashes and underscore the need to strengthen traffic management, enhance AV sensing and decision-making capabilities, and implement targeted safety measures in high-risk areas.
Can AV crash datasets provide more insight if missing information is supplemented? Employing Generative Adversarial Imputation Networks to Tackle Data Quality Issues
No full textThe growing prevalence of autonomous vehicles (AVs) offers new opportunities for enhancing traffic efficiency. However, AVs still face significant challenges that impact their safety and effectiveness in preventing accidents. Real-world operational data is therefore essential to identifying the factors contributing to AV crashes. Despite this, the analysis of AV crashes is still hampered by a lack of data, missing information, and underreporting, which negatively impacts its accuracy and comprehensiveness. To address this challenge, a method based on Generative Adversarial Networks (GANs) was used for data imputation, leveraging their advantage in handling heterogeneous data. An evaluation of the performance of our proposed data imputation approach was performed by comparing it with two established methods, namely conventional case deletion and Random Forest (RF) imputation. Synthetic data obtained from these three methods were modelled using the random parameters logit model with heterogeneity in means. Data from the California Department of Motor Vehicles (DMV) and the National Highway Traffic Safety Administration (NHTSA) covering 2021-2023 were used. Our results showed that the model based on Generative Adversarial Imputation Networks (GAIN)- processing data outperformed other candidate methods in terms of fitting, predictive accuracy, and factor interpretation. Our results suggest that factors including speed limit, roadway types, head-on crashes, and takeover of ADAS-equipped vehicles are positively associated with serious injury crashes. On the other hand, ADS engagement and crashes with fixed objects exhibit a negative association with serious injury crashes. Additionally, heterogeneous effects of posted speed limits and ADS engagement on AV crash severity were captured to provide a deeper insight into implications.
Rigidity of local holomorphic maps between Hermitian symmetric spaces
No full textIn this dessertaion, rigidity of local holomorphic maps between Hermitian symmet ric spaces has been studied. For local holomorphic maps from an irreducible Hermi tian symmetric spaces of compact type to itself, which is equipped with a canonical K¨ahler-Eisntein metric, we show that every map extends to an isometry of the mani fold, provided that the maps satisfy a measure-preserving equation and are generically non-degenerate. To establish the rigidity result, a notion of Serge variety and Segre family in the algebraic setting is introduced. Before obtaining the main theorem, we first prove a basic property for partially degenerate holomorphic maps in a general set ting. Then we establish the Nash-algebraicity for one of these maps by applying this basic property. Here the explicit expression of the mimimal embedding of the manifold into a certain projective space is essentially used. Standard monodormy argument is then applied to show the rationality for this Nash-algebraic map. Lastly by a covering trick we show that the map is a birational map and further an isometry. Hence by induction, we conclude the main theorem. This thesis is based on a joint work with Xiaojun Huang and Ming Xiao ( [FHX])Ph.D.Includes bibliographical referencesby Hanlong Fan
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The role of cynicism and involvement in perceived credibility of media sources among college students
No full textThis study explores the role of political decision making in college students' perceived credibility of media sources. Specifically, it tapped into the associations among perceived credibility of media sources, cynicism and involvement. This study also compared the differences in the levels of perceived credibility between traditional and new media sources. Employing an online survey on Survey Monkey, the study generated responses via three-wave blanket emails and obtained a final sample of 668 responses. The regressions results indicate that cynicism negatively predicts traditional media but not new media sources except political comedy and talk radio. Involvement positively predicts both traditional and new media sources except TV, social networking sites, and talk radio. One way analysis of variance with post-hoc reveals that traditional media sources are significantly more credible than new media sources. Implications of the results were discussed and directions of future research were suggested
An assessment of the 2008 telecommunications restructuring in China
No full textThe restructuring in the Chinese telecom sector in 2008 has prompted heated discussion among telecom analysts and experts. Past research tends to take an optimistic view that China has embarked on a liberalizing route, resulting in utopian projections that domestic competition and foreign liberalizing forces would lead to the emergence of a telecom market operated primarily under the principles of free market economics in the near term. This paper, instead, argues that current telecom restructuring was largely driven by domestic agendas. Drawing from the bargaining perspective, this paper finds that, while it is true that market mechanisms play a significant role in the telecom industry, the impact of competition and privatization on the telecom market ultimately depends on the political endowments of Chinese society.Telecommunications restructuring Regulations Bargaining perspective China
