scholarly journals Dissipation of stop-and-go waves via control of autonomous vehicles: Field experiments

2018 ◽  
Vol 89 ◽  
pp. 205-221 ◽  
Author(s):  
Raphael E. Stern ◽  
Shumo Cui ◽  
Maria Laura Delle Monache ◽  
Rahul Bhadani ◽  
Matt Bunting ◽  
...  
Keyword(s):  
Autonomous Vehicles ◽  
Field Experiments ◽  
Stop And Go

Stop-and-go approach by a predator: a novel predation risk factor for the phrynosomatid lizards Sceloporus virgatus and Callisaurus draconoides

2015 ◽  
Vol 36 (4) ◽  
pp. 401-409
Author(s):  
William E. Cooper ◽  
Wade C. Sherbrooke
Keyword(s):  
Field Experiments ◽  
Empirical Studies ◽  
Pause Duration ◽  
Predator Prey ◽  
Escape Theory ◽  
Stop And Go ◽  
Approach Speed ◽  
Sceloporus Virgatus ◽  
Escape Behaviors ◽  
Flight Initiation

As an immobile prey monitors an approaching predator, the predator may move at a constant speed directly toward the prey or on a path that bypasses the prey. These scenarios have been studied extensively. Economic escape theory successfully predicts flight initiation distance (FID = predator-prey distance when escape begins). However, predators often alter their speed and may exhibit stops and starts during approaches. Empirical studies have shown that prey rapidly adjust assessed risk to a predator’s changes in approach speed and direction, but effects of interrupted (stop-start) approach are unknown. Because a prey is likely to assess that a nearby predator that resumes approaching has detected it and is attacking, escape theory predicts that assessed risk is greater at a given predator-prey distance when approach resumes than is continuous. Therefore, we predicted that FID is longer when a predator approaches, stops nearby, and renews its approach than when it approaches continuously. Second, although assessed risk increases as duration of the predator’s stop nearby increases, as indicated by latency to flee, we predicted that pause duration does not affect FID because prey interpret resumed approach as attack. Field experiments with two lizards, Sceloporus virgatus and Callisaurus draconoides, verified the predictions: FID was longer for discontinuous than continuous approaches and pause duration did not affect FID. We also observed distance fled and probability of entering refuge, escape behaviors for which theory is undeveloped. Distance fled was unrelated to continuity of approach in both species, as was refuge entry in S. virgatus.

scholarly journals Automated Conflict Management Framework Development for Autonomous Aerial and Ground Vehicles

Energies ◽  
2021 ◽  
Vol 14 (24) ◽  
pp. 8344
Author(s):  
David Sziroczák ◽  
Daniel Rohács
Keyword(s):  
Conflict Management ◽  
Autonomous Vehicles ◽  
Unmanned Vehicles ◽  
Urban Traffic ◽  
Ground Vehicles ◽  
Management Framework ◽  
Incremental Development ◽  
Stop And Go ◽  
High Level ◽  
Framework Development

The number of aerial- and ground-based unmanned vehicles and operations is expected to significantly expand in the near future. While aviation traditionally has an excellent safety record in managing conflicts, the current approaches will not be able to provide safe and efficient operations in the future. This paper presents the development of a novel framework integrating autonomous aerial and ground vehicles to facilitate short- and mid-term tactical conflict management. The methodology presents the development of a modular web service framework to develop new conflict management algorithms. This new framework is aimed at managing urban and peri-urban traffic of unmanned ground vehicles and assisting the introduction of urban air mobility into the same framework. A set of high-level system requirements is defined. The incremental development of two versions of the system prototype is presented. The discussions highlight the lessons learnt while implementing and testing the conflict management system and the introduced version of the stop-and-go resolution algorithm and defines the identified future development directions. Operation of the system was successfully demonstrated using real hardware. The developed framework implements short- and mid-term conflict management methodologies in a safe, resource efficient and scalable manner and can be used for the further development and the evaluation of various methods integrating aerial- and ground-based autonomous vehicles.

scholarly journals The Adoption of Green Vehicles in Last Mile Logistics: A Systematic Review

2020 ◽  
Vol 13 (1) ◽  
pp. 6
Author(s):  
Sergio Maria Patella ◽  
Gianluca Grazieschi ◽  
Valerio Gatta ◽  
Edoardo Marcucci ◽  
Stefano Carrese
Keyword(s):  
Systematic Review ◽  
Autonomous Vehicles ◽  
Empirical Literature ◽  
Negative Externalities ◽  
Public Authorities ◽  
Urban Freight ◽  
Stop And Go ◽  
Last Mile ◽  
Green Vehicles ◽  
Selection Of

Widespread adoption of green vehicles in urban logistics may contribute to the alleviation of problems such as environmental pollution, global warming, and oil dependency. However, the current adoption of green vehicles in the last mile logistics is relatively low despite many actions taken by public authorities to overcome the negative externalities of distributing goods in cities. This paper presents a comprehensive literature review on studies investigating the adoption of green vehicles in urban freight transportation, paying specific attention to e-commerce. To shed light on the adoption of green vehicles in city logistics, the paper conducts a systematic review of the empirical literature on the topic. The 159 articles reviewed were classified into the following: (a) Optimization and scheduling (67 papers); (b) policy (55 papers); (c) sustainability (37 papers). Among the 159 articles, a further selection of 17 papers dealing with e-commerce, i.e., studies that highlight the most relevant aspects related to the integration of green vehicles in e-commerce urban logistics, was performed. Our findings indicate that green vehicles are competitive in urban deliveries characterized by frequent stop-and-go movements and low consolidation levels while incentives are still necessary for their adoption. The use of autonomous vehicles results the most promising and challenging solution for last-mile logistics.

scholarly journals Design of Field Experiments for Adaptive Sampling of the Ocean with Autonomous Vehicles

2010 ◽  
Author(s):  
H. Zheng ◽  
B. H. Ooi ◽  
W. Cho ◽  
M. H. Dao ◽  
P. Tkalich ◽  
...  
Keyword(s):  
Autonomous Vehicles ◽  
Adaptive Sampling ◽  
Field Experiments

scholarly journals Advanced e-Call Support Based on Non-Intrusive Driver Condition Monitoring for Connected and Autonomous Vehicles

Sensors ◽  
2021 ◽  
Vol 21 (24) ◽  
pp. 8272
Author(s):  
Marius Minea ◽  
Cătălin Marian Dumitrescu ◽  
Ilona Mădălina Costea
Keyword(s):  
Autonomous Vehicles ◽  
Field Experiments ◽  
The Internet ◽  
Cognitive State ◽  
Negative Consequences ◽  
Road Accidents ◽  
Timely Manner ◽  
Vital Functions ◽  
Sensor Structure ◽  
Call System

Background: The growth of the number of vehicles in traffic has led to an exponential increase in the number of road accidents with many negative consequences, such as loss of lives and pollution. Methods: This article focuses on using a new technology in automotive electronics by equipping a semi-autonomous vehicle with a complex sensor structure that is able to provide centralized information regarding the physiological signals (Electro encephalogram—EEG, electrocardiogram—ECG) of the driver/passengers and their location along with indoor temperature changes, employing the Internet of Things (IoT) technology. Thus, transforming the vehicle into a mobile sensor connected to the internet will help highlight and create a new perspective on the cognitive and physiological conditions of passengers, which is useful for specific applications, such as health management and a more effective intervention in case of road accidents. These sensor structures mounted in vehicles will allow for a higher detection rate of potential dangers in real time. The approach uses detection, recording, and transmission of relevant health information in the event of an incident as support for e-Call or other emergency services, including telemedicine. Results: The novelty of the research is based on the design of specialized non-invasive sensors for the acquisition of EEG and ECG signals installed in the headrest and backrest of car seats, on the algorithms used for data analysis and fusion, but also on the implementation of an IoT temperature measurement system in several points that simultaneously uses sensors based on MEMS technology. The solution can also be integrated with an e-Call system for telemedicine emergency assistance. Conclusion: The research presents both positive and negative results of field experiments, with possible further developments. In this context, the solution has been developed based on state-of-the-art technical devices, methods, and technologies for monitoring vital functions of the driver/passengers (degree of fatigue, cognitive state, heart rate, blood pressure). The purpose is to reduce the risk of accidents for semi-autonomous vehicles and to also monitor the condition of passengers in the case of autonomous vehicles for providing first aid in a timely manner. Reported abnormal values of vital parameters (critical situations) will allow interveneing in a timely manner, saving the patient’s life, with the support of the e-Call system.

Traffic Oscillation using Stochastic Lagrangian Dynamics: Simulation and Mitigation via Control of Autonomous Vehicles

2019 ◽  
Vol 2673 (7) ◽  
pp. 1-11
Author(s):  
Fangfang Zheng ◽  
Liang Lu ◽  
Ruijie Li ◽  
Xiaobo Liu ◽  
Youhua Tang
Keyword(s):  
Traffic Flow ◽  
Autonomous Vehicles ◽  
Control Strategies ◽  
Dynamics Simulation ◽  
Lagrangian Model ◽  
Mixed Traffic ◽  
Mixed Traffic Flow ◽  
Sample Paths ◽  
Stop And Go ◽  
The Impact

The phenomenon of stop-and-go waves is frequently observed in congested traffic. With the development of connected and autonomous vehicle (CAV) technologies, it is possible to reduce traffic oscillation via control of CAVs in a mixed traffic flow with both human drivers and autonomous vehicles (AVs). This paper introduces a stochastic Lagrangian model which is capable of simulating stop-and-go traffic considering the heterogeneity of drivers. The sample paths of the stochastic process are smooth without aggressive oscillation. The model is further extended to the mixed traffic flow condition, considering stochastic human driving behavior and deterministic behavior of AVs. With the proposed model, the variation of performance of AV control strategies can be quantified in addition to the average performance. A numerical example with a single lane circular road is used to investigate the impact of the AV control strategy on mitigating stop-and-go waves. Both qualitative and quantitative results show that the phenomenon of stop-and-go waves can be reduced significantly with only one AV, while the increase of AVs from 10% (two AVs) to 50% (10 AVs) offers just marginal improvement in relation to the ensemble-averaged performance and 95% confidence interval of the ensemble-averaged performance. The proposed simulation approach based on the stochastic Lagrangian model can effectively investigate the impact of AV control strategies on traffic oscillation, considering in particular the uncertainty of human driver behavior.

REEEC-AGENT: human driver cognition and emotions-inspired rear-end collision avoidance method for autonomous vehicles

SIMULATION ◽  
2021 ◽  
pp. 003754972110047
Author(s):  
Muhammad A Butt ◽  
Faisal Riaz ◽  
Yasir Mehmood ◽  
Somyyia Akram
Keyword(s):  
Real Time ◽  
Collision Avoidance ◽  
Collision Detection ◽  
Autonomous Vehicles ◽  
Affective Computing ◽  
Field Experiments ◽  
Road Traffic ◽  
Sensory System ◽  
Driving Mode ◽  
Human Driver

Rear-end collision detection and avoidance is one of the most crucial driving tasks of self-driving vehicles. Mathematical models and fuzzy logic-based methods have recently been proposed to improve the effectiveness of the rear-end collision detection and avoidance systems in autonomous vehicles (AVs). However, these methodologies do not tackle real-time object detection and response problems in dense/dynamic road traffic conditions due to their complex computation and decision-making structures. In our previous work, we presented an affective computing-inspired Enhanced Emotion Enabled Cognitive Agent (EEEC_Agent), which is capable of rear-end collision avoidance using artificial human driver emotions. However, the architecture of the EEEC_Agent is based on an ultrasonic sensory system which follows three-state driving strategies without considering the neighbor vehicles types. To address these issues, in this paper we propose an extended version of the EEEC_Agent which contains human driver-inspired dynamic driving mode controls for autonomous vehicles. In addition, a novel end-to-end learning-based motion planner has been devised to perceive the surrounding environment and regulate driving tasks accordingly. The real-time in-field experiments performed using a prototype AV demonstrate the effectiveness of this proposed rear-end collision avoidance system.

Electron Microscopy of the Shape of Small Metal Particles

1977 ◽  
Vol 35 ◽  
pp. 300-301
Author(s):  
M. Jose Yacaman
Keyword(s):  
Electron Microscopy ◽  
Metal Particle ◽  
Field Experiments ◽  
Size Range ◽  
Dark Field ◽  
Metal Particles ◽  
Bragg Condition ◽  
Crystal Particle ◽  
Small Metal Particle ◽  
Small Metal Particles

In the Study of small metal particles the shape is a very Important parameter. Using electron microscopy Ino and Owaga(l) have studied the shape of twinned particles of gold. In that work electron diffraction and contrast (dark field) experiments were used to produce models of a crystal particle. In this work we report a method which can give direct information about the shape of an small metal particle in the amstrong- size range with high resolution. The diffraction pattern of a sample containing small metal particles contains in general several systematic and non- systematic reflections and a two-beam condition can not be used in practice. However a N-beam condition produces a reduced extinction distance. On the other hand if a beam is out of the bragg condition the effective extinction distance is even more reduced.

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