15,406 research outputs found
Trials with Microwave Detection of Vulnerable Road Users and Preliminary Empirical Modal Test. DRIVE Project V1031 Deliverable 11.
The general objective of the project is to provide a set of tools for the creation of traffic systems that enhance the safety and mobility of vulnerable road users (VRUs). This is being achieved in two ways: 1. By evaluating a number of RTI applications in signalling and junction control, in order to ascertain what benefits can be obtained for vulnerable road users by such local measures. 2. By developing a model of the traffic system that incorporates vulnerable road users as an integral part. The present workpackage, one of the last ones within the project, is intended to link the two strands together. The workpackage consists of two main parts: 1. Experiments with pedestrians and bicyclists. Two experiments were carried out, one in England (Bradford) and one in Sweden (Vijrjo), both applying microwave detectors for detection of pedestrians in a signalized intersection, but applying the detection in different ways. An observational study was carried out in Groningen (the Netherlands) to analyze bicycle/car interactions at an intersection with a cycle path. The aim of the experiment was to test the usefulness of a system giving car drivers warning in situations when a bicyclist approaches an intersection on a parallel bicycle path. 2. Reliability and validity testing of the submodels of the VRU-oriented traffic model WLCAN
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Explainable and Advisable Learning for Self-driving Vehicles
Deep neural perception and control networks are likely to be a key component of self-driving vehicles. These models need to be explainable - they should provide easy-to-interpret rationales for their behavior - so that passengers, insurance companies, law enforcement, developers, etc., can understand what triggered a particular behavior. Explanations may be triggered by the neural controller, namely introspective explanations, or informed by the neural controller's output, namely rationalizations. Our work has focused on the challenge of generating introspective explanations of deep models for self-driving vehicles. In Chapter 3, we begin by exploring the use of visual explanations. These explanations take the form of real-time highlighted regions of an image that causally influence the network's output (steering control). In the first stage, we use a visual attention model to train a convolution network end-to-end from images to steering angle. The attention model highlights image regions that potentially influence the network's output. Some of these are true influences, but some are spurious. We then apply a causal filtering step to determine which input regions actually influence the output. This produces more succinct visual explanations and more accurately exposes the network's behavior. In Chapter 4, we add an attention-based video-to-text model to produce textual explanations of model actions, e.g. "the car slows down because the road is wet". The attention maps of controller and explanation model are aligned so that explanations are grounded in the parts of the scene that mattered to the controller. We explore two approaches to attention alignment, strong- and weak-alignment. These explainable systems represent an externalization of tacit knowledge. The network's opaque reasoning is simplified to a situation-specific dependence on a visible object in the image. This makes them brittle and potentially unsafe in situations that do not match training data. In Chapter 5, we propose to address this issue by augmenting training data with natural language advice from a human. Advice includes guidance about what to do and where to attend. We present the first step toward advice-giving, where we train an end-to-end vehicle controller that accepts advice. The controller adapts the way it attends to the scene (visual attention) and the control (steering and speed). Further, in Chapter 6, we propose a new approach that learns vehicle control with the help of long-term (global) human advice. Specifically, our system learns to summarize its visual observations in natural language, predict an appropriate action response (e.g. "I see a pedestrian crossing, so I stop"), and predict the controls, accordingly
Passenger Flows in Underground Railway Stations and Platforms, MTI Report 12-43
Urban rail systems are designed to carry large volumes of people into and out of major activity centers. As a result, the stations at these major activity centers are often crowded with boarding and alighting passengers, resulting in passenger inconvenience, delays, and at times danger. This study examines the planning and analysis of station passenger queuing and flows to offer rail transit station designers and transit system operators guidance on how to best accommodate and manage their rail passengers. The objectives of the study are to: 1) Understand the particular infrastructural, operational, behavioral, and spatial factors that affect and may constrain passenger queuing and flows in different types of rail transit stations; 2) Identify, compare, and evaluate practices for efficient, expedient, and safe passenger flows in different types of station environments and during typical (rush hour) and atypical (evacuations, station maintenance/ refurbishment) situations; and 3) Compile short-, medium-, and long-term recommendations for optimizing passenger flows in different station environments
A large-scale real-life crowd steering experiment via arrow-like stimuli
We introduce "Moving Light": an unprecedented real-life crowd steering
experiment that involved about 140.000 participants among the visitors of the
Glow 2017 Light Festival (Eindhoven, NL). Moving Light targets one outstanding
question of paramount societal and technological importance: "can we seamlessly
and systematically influence routing decisions in pedestrian crowds?"
Establishing effective crowd steering methods is extremely relevant in the
context of crowd management, e.g. when it comes to keeping floor usage within
safety limits (e.g. during public events with high attendance) or at designated
comfort levels (e.g. in leisure areas). In the Moving Light setup, visitors
walking in a corridor face a choice between two symmetric exits defined by a
large central obstacle. Stimuli, such as arrows, alternate at random and
perturb the symmetry of the environment to bias choices. While visitors move in
the experiment, they are tracked with high space and time resolution, such that
the efficiency of each stimulus at steering individual routing decisions can be
accurately evaluated a posteriori. In this contribution, we first describe the
measurement concept in the Moving Light experiment and then we investigate
quantitatively the steering capability of arrow indications.Comment: 8 page
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