1,720,967 research outputs found
Modelling and Control Approaches to System of Systems applied to Water Tank Systems and Autonomous Vehicle Platooning
No full textThe realm of control in System of Systems (SoS) is distinct from ordinary systems and covers a wide range of applications. The variance arises from the collective capabilities derived from the interconnections within the SoS, giving it a group capability beyond its components. The study of such systems can be intricate, and the challenges can vary between similar cases, necessitating distinct resolutions. Over the last two decades, researchers and industries have concentrated on the automotive sector to reduce fuel consumption, fatal collisions, and traffic congestion. A road vehicle, as a system of systems, consists of several modules that require extensive research to optimize. Approaches for controlling, predicting, and recognizing pedestrians and obstacles can vary from a simple yet effective Proportion Integral Derivative (PID) controller to data-driven methods such as Artificial Neural Networks (ANNs). Ongoing research also considers other scenarios, such as platooning in heavy-duty vehicles and urban areas. Platooning refers to a convoy of vehicles that follow the same route. They maintain proximity to reduce fuel consumption and progress as a unified unit. This is standard practice for human-driven vehicles (HDVs), and it is imperative for self-driving vehicles dedicated to logistics transportation, enabling drivers to rest and decrease travelling time.
This thesis examines Systems of Systems (SoS) in various contexts, including autonomous driving systems, mathematical models, and case studies. Chapter one provides an overview of the state of the art in SoS control and the materials used in this thesis, from simulation software to hardware where the presented algorithms are implemented. Chapter two, the core of the thesis, explores the different mathematical models that can be used for the various case studies. The following section will provide a detailed explanation of each case study and its proposed solution. The case studies include a classical SoS, such as the Quadruple Water Tank Plant (QTP) control, vehicle trajectory and safety approaches, and platooning scenarios in different contexts. The final section offers insights for further research and development, highlighting potential areas for improving autonomous driving in complex scenarios
Distributed Predictive Control for Roundabout Crossing Modelled by Virtual Platooning
No full textRoundabouts pose complex challenges for autonomous vehicles. Approaching and crossing them safely requires a significant amount of information, much of which is typically unavailable. With autonomous vehicles becoming increasingly prevalent on the roads, new approaches are necessary to address these upcoming issues. While platoons and distributed control have been extensively studied in the past decade, roundabouts have received less attention. This paper presents a distributed Nonlinear Model Predictive Control (NMPC) approach using the Alternating Direction Method of Multipliers (ADMM) to utilize virtual platooning and enhance the throughput of a roundabout without requiring approaching vehicles to come to a stop. Instead, it manages the velocity of each vehicle while maintaining a safe distance. The proposed approach is validated through two case studies
Distributed Control of a System of Systems: An Alternating Direction Method of Multipliers Approach
No full text
Path Tracking for Wheeled Mobile Robot Using Non Linear Model Predictive Control in Indoor Environment
No full textWheeled Mobile Robots (WMR) with the assistance of Information Communication Technology (ICT) can navigate and perform some tasks in an uncontrolled environment. They can experience some problems in task management if they can not localize themself in indoor/outdoor environments. Different algorithms can be exploited to evaluate the proper control law to track a default path. In this paper, a path-tracking algorithm for a WMR has been tested for an indoor environment, with a delimited area spanned by localization tags. The WMR must check some waypoints during its path until the last one, where the WMR re-start the simulation. In this work, the control law applied for the experiments is the Non-Linear Model Predictive Controller (NMPC). The control algorithm is tested using two experiments, the first one is based on the robot movements in a simulation environment using the Gazebo tools, and the second one is related to a real context where the mobile robot moves in an indoor environment
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe 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
Full text link“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
Appropriate Similarity Measures for Author Cocitation Analysis
Full text linkWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
- …
