version of S, so that g(x) = 0 correctly characterizes S A . Then the "y → 0" idealization functions to transform one description -viz., f(x,y) = 0 -into a (more) incomplete description -viz., g(x) = 0; and the "y → 0" idealization determines which details g(x) = 0 ignores about S and the respects in which S A is an abstract version of S. Provided that there is an appropriate relationship betwe...

This letter proposes a new reinforcement learning (RL) paradigm that explicitly takes into account input disturbance as well as modeling errors. The use of environmental models in RL is quite popular for both offline learning using simulations and for online action planning. However, the difference between the model and the real environment can lead to unpredictable, and often unwanted, results...

Structural optimization of non-conservative systems with respect to stability criteria is a research area with important applications in fluid-structure interactions, friction-induced instabilities, and civil engineering. In contrast to optimization of conservative systems where rigorously proven optimal solutions in buckling problems have been found, for non-conservative optimization problems ...

When two macroscopic bodies in contact slide, energy is dissipated. However, at the nanoscale, tiny amounts of energy can also be dissipated when the sliding bodies are not in contact with each other. Such non-contact form of friction — the origin of which has been associated with van der Waals (vdW) forces — has been measured with highly sensitive atomic force microscopy (AFM). In a friction f...

The recent development of on chip integration of magneto-optic isolators is reviewed. Two major categories of structural designs for waveguide isolator (nonreciprocal mode conversion and nonreciprocal phase shift) have both merits and short comings for integration. The advances in integration techniques and materials related developments in the last decade are a big step towards monolithic inte...

This paper describes an experimental investigation conducted on WRS-BTU seismic isolators that are constituted by a wire rope spring coupled with a ball transfer unit. The device can be considered rigid along the vertical direction while the horizontal stiffness can be independently chosen to shift the natural period away from the period range having the most of earthquake energy. Two kinds of ...

conventional methods for seismic design of structures are based on building capacity. because of the disadvantages of conventional methods, base isolation system  is known as an effective solution to protect structures against earthquakes. in this study the operation of 2-storey steel frame with and without seismic isolators under near-fault earthquake of chichi، northridge and  capemendocine  ...

In general, a Variable Structure (VS) system is designed with a sliding mode. Recently a sliding sector, designed by an algebraic Riccati equation, has been proposed to replace the sliding mode for chattering-free VS controllers. In this paper we extend the design algorithm for the sliding sector to a time-varying sliding sector. The time-varying sliding sector is defined by functions dependent...