92,276 research outputs found
The role of angularity in route choice: an analysis of motorcycle courier GPS traces
The paths of 2425 individual motorcycle trips made in London
were analyzed in order to uncover the route choice decisions made
by drivers. The paths were derived from global positioning system (GPS)
data collected by a courier company for each of their drivers, using algorithms
developed for the purpose of this paper. Motorcycle couriers were
chosen due to the fact that they both know streets very well and that
they do not rely on the GPS to guide their navigation. Each trace was
mapped to the underlying road network, and two competing hypotheses
for route choice decisions were compared: (a) that riders attempt to
minimize the Manhattan distance between locations and (b) that they
attempt to minimize the angular distance. In each case, the distance actually
traveled was compared to the minimum possible either block or
angular distance through the road network. It is usually believed that
drivers who know streets well will navigate trips that reduce Manhattan
distance; however, here it is shown that angularity appears to play an
important role in route choice. 63% of trips made took the minimum
possible angular distance between origin and destination, while 51% of
trips followed the minimum possible block distance. This implies that
impact of turns on cognitive distance plays an important role in decision
making, even when a driver has good knowledge of the spatial network
QoE in Pull Based P2P-TV Systems: Overlay Topology Design Tradeoff
Abstract—This paper presents a systematic performance anal-ysis of pull P2P video streaming systems for live applications, providing guidelines for the design of the overlay topology and the chunk scheduling algorithm. The contribution of the paper is threefold: 1) we propose a realistic simulative model of the system that represents the effects of access bandwidth heterogeneity, latencies, peculiar characteristics of the video, while still guaranteeing good scalability properties; 2) we propose a new latency/bandwidth-aware overlay topology design strategy that improves application layer performance while reducing the underlying transport network stress; 3) we investigate the impact of chunk scheduling algorithms that explicitly exploit properties of encoded video. Results show that our proposal jointly improves the actual Quality of Experience of users and reduces the cost the transport network has to support. I
Navigating Occluded Intersections with Autonomous Vehicles using Deep Reinforcement Learning
Providing an efficient strategy to navigate safely through unsignaled
intersections is a difficult task that requires determining the intent of other
drivers. We explore the effectiveness of Deep Reinforcement Learning to handle
intersection problems. Using recent advances in Deep RL, we are able to learn
policies that surpass the performance of a commonly-used heuristic approach in
several metrics including task completion time and goal success rate and have
limited ability to generalize. We then explore a system's ability to learn
active sensing behaviors to enable navigating safely in the case of occlusions.
Our analysis, provides insight into the intersection handling problem, the
solutions learned by the network point out several shortcomings of current
rule-based methods, and the failures of our current deep reinforcement learning
system point to future research directions.Comment: IEEE International Conference on Robotics and Automation (ICRA 2018
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