1,721,096 research outputs found
Evaluation of MEMS sensors accuracy based on an instrumented bicycle for the purpose of tracking and positioning
No full textDevelopment and testing of a prototype instrumented bicycle model for the prevention of cyclist accidents
No full textCycling is an increasingly popular mode of travel in cities owing to the great advantages that it offers in terms of space consumption, health and environmental sustainability, and is therefore favoured and promoted by many city authorities worldwide. However, cycling is also perceived as relatively unsafe, and therefore it has yet to be adopted as a viable alternative to the private car. Rising accident numbers, unfortunately, confirm this perception as reality, with a particular source of hazard (and a significant proportion of collisions) appearing to originate from the interaction of cyclists with Heavy Vehicles (HVs). This paper introduces Cyclist 360° Alert, a novel technological solution aimed at tackling this problem and ultimately improving the safety of cyclists and promoting it to non-riders. Following a thorough review of the trends of cyclist collisions, which sets the motivation of the research, the paper goes on to present the Cyclist 360° Alert system architecture design, and examines possible technologies and techniques that can be employed in the accurate positioning of cyclists and vehicles. It then focuses in particular on the aspect of bicycle tracking, and proposes a localisation approach based on micro-electromechanical systems (MEMS) sensor configurations. Initial experimental results from a set of controlled experiments using a purpose-developed prototype bicycle simulator model, are reported, and conclusions on the applicability of specific sensor configurations are drawn, both in terms of sensor accuracy and reliability in taking sample measurements of motion
Cyclist 360° Alert: Validation of an instrumented bicycle trajectory reconstruction mechanism using satellite and inertial navigation systems
No full textA novel fusion algorithm to improve localisation accuracy of an instrumented bicycle
Get PDFCycling is an increasingly popular mode of travel in cities due to the great advantages that it offers in terms of space consumption, health and environmental sustainability, and is therefore favoured and promoted by many city authorities. However, the relatively low perceived safety of cycling from the users’ side currently presents itself as a hurdle towards higher uptake levels of cycling, and unfortunately, road accident statistics (1) confirm this perception as reality. A typical collision pattern observed involves cyclists being “crushed” by turning motorised vehicles, due to their presence in the so-called “blind spot”, which is to the left of the vehicle in the UK and to the right in countries with right - hand traffic (2). Up until a few years ago, th e only options for tackling such a problem would be drawn from the domain of “hard” traffic engineering measures, (usually cost-intensive and/or severely disruptive, such as segregated lanes or vehicle type bans in certain streets). However, trends in the development of ubiquitous computing now offer smaller, more accurate and durable tools to support traffic safety interventions. Examples range from simple passive measures (3) to more advanced experimental active cyclist detection system (4). But while such solutions certainly represent steps in the right direction in terms of preventing cyclist - vehicle collisions, they are limited in what they are unable to perform any reliable prediction of accidents due to their inability to accurately track the cyclist’s trajectory and estimate his/her position in a critical time-horizon of 5-10 seconds. Indeed, the accurate (< 1 m) localisation of the cyclist is a necessity when it comes to preventing collisions, but so far remains an important unresolved challenge, as none of the existing mainstream technologies (GPS, WiFi etc.) can achieve it. Enhanced positioning systems, on the other hand, such as U-blox (5) and Spatial (6) Inertial Navigation System (INS), can achieve accurate positioning in theory, but they are specifically designed for four-wheel vehicles and are therefore very expensive when used for tracking bicycles. Besides, the dynamics of a bicycle is very complex and different from an ordinary vehicle, and so the accuracy of such enhanced positioning syst ems will differ greatly when used on a bicycle. The research reported here focuses on the development and testing of an innovative technological solution for accurately localising and tracking cyclists in urban environments using a low-cost micro-electrome chanical systems (MEMS) sensor configuration on a prototype instrumented bicycle system, called “ iBike ” (7). The ultimate goal is to develop a collision prediction and avoidance system, and the present paper presents a novel fusion technique that could be utilised to improve localisation accuracy based on Wireless Communication Technologies (WCT) widely found in cities as well as Global Navigation Satellite System (GNSS) positioning
Using an instrumented bicycle to explore the responses of cyclists to pavement characteristics and defects
No full textDevelopment and testing of a prototype instrumented bicycle for the prevention of cyclist accidents
No full textAn innovative multi-sensor fusion algorithm to enhance positioning accuracy of an instrumented bicycle
Get PDFCycling is an increasingly popular mode of travel in cities, but its poor safety record currently acts as a hurdle to its wider adoption as a real alternative to the private car. A particular source of hazard appears to originate from the interaction of cyclists with motorized traffic at low speeds in urban areas. But while technological advances in recent years have resulted in numerous attempts at systems for preventing cyclist-vehicle collisions, these have generally encountered the challenge of accurate cyclist localization. This paper addresses this challenge by introducing an innovative bicycle localization algorithm, which is derived from the geometrical relationships and kinematics of bicycles. The algorithm relies on the measurement of a set of kinematic variables (such as yaw, roll, and steering angles) through low-cost on-board sensors. It then employs a set of Kalman filters to predict-correct the direction and position of the bicycle and fuse the measurements in order to improve positioning accuracy. The capabilities of the algorithm are then demonstrated through a real-world field experiment using an instrumented bicycle, called "iBike'', in an urban environment. The results show that the proposed fusion achieves considerably lower positioning errors than that would be achieved based on dead-reckoning alone, which makes the algorithm a credible basis for the development of future collision warning and avoidance systems
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Get PDF“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
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