Concordia University

About: Concordia University is a education organization based out in Montreal, Quebec, Canada. It is known for research contribution in the topics: Context (language use) & Control theory. The organization has 13565 authors who have published 31084 publications receiving 783525 citations. The organization is also known as: Sir George Williams University & Loyola College, Montreal.

Spacetime and Geometry

Abstract: This chapter elaborates the spacetime and geometry. Mathematics in the modern sense may be said to have originated in the work of Euclid. It is found that prior to this time the various truths of geometry had been treated as isolated, or mutually independent. The essence of the axiomatic method in geometry is to demonstrate that the truth of all geometric theorems depends solely on the truth of a proper subset of them, the axioms, from which all of the former are derivable. The famous Euclidean parallels postulate was thought to lack the self-evident character of the remaining axioms. The parallels postulate may be expressed as the claim that through any point in a plane of a given straight line there is one, and only one straight line which does not intersect the given line. It appeared to Euclid's successors that such an assumption marred the perfection of his system in so far as it involves not simply line segments but the entire Euclidean plane extended to infinity.

Microclimate and Downtown Open Space Activity

Abstract: Microclimatic conditions in business district open spaces tend to be more extreme than prevailing weather conditions. Although the buildings are chiefly responsible for this inclemency, their shape...

Neural-Adaptive Control of Single-Master–Multiple-Slaves Teleoperation for Coordinated Multiple Mobile Manipulators With Time-Varying Communication Delays and Input Uncertainties

Abstract: In this paper, adaptive neural network control is investigated for single-master-multiple-slaves teleoperation in consideration of time delays and input dead-zone uncertainties for multiple mobile manipulators carrying a common object in a cooperative manner. Firstly, concise dynamics of teleoperation systems consisting of a single master robot, multiple coordinated slave robots, and the object are developed in the task space. To handle asymmetric time-varying delays in communication channels and unknown asymmetric input dead zones, the nonlinear dynamics of the teleoperation system are transformed into two subsystems through feedback linearization: local master or slave dynamics including the unknown input dead zones and delayed dynamics for the purpose of synchronization. Then, a model reference neural network control strategy based on linear matrix inequalities (LMI) and adaptive techniques is proposed. The developed control approach ensures that the defined tracking errors converge to zero whereas the coordination internal force errors remain bounded and can be made arbitrarily small. Throughout this paper, stability analysis is performed via explicit Lyapunov techniques under specific LMI conditions. The proposed adaptive neural network control scheme is robust against motion disturbances, parametric uncertainties, time-varying delays, and input dead zones, which is validated by simulation studies.