Two definitions of the electric polarizability of a bound system in relativistic quantum theory

For the electric polarizability of a bound system in relativistic quantum theory, there are two definitions that have appeared in the literature. They differ depending on whether or not the vacuum background is included in the system. A recent confusion in this connection is clarified. © 1999 American Associations of Physics Teachers.

Planning “Discrete” Movements Using a Continuous System: Insights from a Dynamic Field Theory of Movement Preparation

The timed-initiation paradigm developed by Ghez and colleagues (1997) has revealed two modes of motor planning: continuous and discrete. Continuous responding occurs when targets are separated by less than 60° of spatial angle, and discrete responding occurs when targets are separated by greater than 60°. Although these two modes are thought to reflect the operation of separable strategic planning systems, a new theory of movement preparation, the Dynamic Field Theory, suggests that two modes emerge flexibly from the same system. Experiment 1 replicated continuous and discrete performance using a task modified to allow for a critical test of the single system view. In Experiment 2, participants were allowed to correct their movements following movement initiation (the standard task does not allow corrections). Results showed continuous planning performance at large and small target separations. These results are consistent with the proposal that the two modes reflect the time-dependent “preshaping” of a single planning system.

Adaptive control system based on lineal control theory for the path-following problem of a car-like mobile robot

The objective of this paper is to design a path following control system for a car-like mobile robot using classical linear control techniques, so that it adapts on-line to varying conditions during the trajectory following task. The main advantages of the proposed control structure is that well known linear control theory can be applied in calculating the PID controllers to full control requirements, while at the same time it is exible to be applied in non-linear changing conditions of the path following task. For this purpose the Frenet frame kinematic model of the robot is linearised at a varying working point that is calculated as a function of the actual velocity, the path curvature and kinematic parameters of the robot, yielding a transfer function that varies during the trajectory. The proposed controller is formed by a combination of an adaptive PID and a feed-forward controller, which varies accordingly with the working conditions and compensates the non-linearity of the system. The good features and exibility of the proposed control structure have been demonstrated through realistic simulations that include both kinematics and dynamics of the car-like robot.

State Convergence Theory Applied to a Delayed Teleoperation System

State convergence is a control strategy that was proposed in the early 2000s to ensure stability and transparency in a teleoperation system under specific control gains values. This control strategy has been implemented for a linear system with or without time delay. This paper represents the first attempt at demonstrating, theoretically and experimentantally, that this control strategy can also be applied to a nonlinear teleoperation system with n degrees of freedom and delay in the communication channel. It is assumed that the human operator applies a constant force on the local manipulator during the teleoperation. In addition, the interaction between the remote manipulator and the environment is considered passive. Communication between the local and remote sites is made by means of a communication channel with variable time delay. In this article the theory of Lyapunov-Krasovskii was used to demonstrate that the local-remote teleoperation system is asymptotically stable.

The political science of John Adams; a study in the theory of mixed government and the bicameral system,

Mode of access: Internet.

The absorption refrigerating machine, elementary theory and practice, a complete practical elementary treatise on the absorption system of refrigeration, and its general fundamental principles of operation.

Mode of access: Internet.

The system or theory of the trade of the world.

Original t. p. has imprint: London, Printed by H. Woodfall; sold by J. Roberts, M.DC.XX.

Astronomy improved: or, A new theory of the harmonious regularity observable in the mechanism or movements of the planetary system. In three lectures, read in the chapel of Yale-college, in New-Haven. Begun February 17, 1781 ...

Evans 18797.

The divine theory : a system of divinity, founded wholly upon Christ: which, by one principle, offers an explanation of all the works of God /

Mode of access: Internet.

A treatise on surveying : containing the theory and practice : to which is prefixed a perspicuous system of plane trigonometry /

The above entries appear to constitute one work. cf. A treatise on surveying, p. 7.

A treatise on surveying : containing the theory and practice : to which is prefixed a perspicuous system of plane trigonometry : the whole clearly demonstrated and illustrated by a large number of appropriate examples, particularly adapted to the use of schools /

With: Mathematical tables / John Gummere. Stereotyped ed., carefully rev. and corrected. Philadelphia : Kimber & Sharpless, 1843.

A treatise on surveying, containing the theory and practice: to which is prefixed a perspicuous system of plane trigonometry.

Mode of access: Internet.

An attempt to exhibit the true theory of Christianity as a consistent and practical system.

Mode of access: Internet.