From Causal Relations to Causal Constraints

This book explores the notion of causal constraint in science. It examines a family of general constraints encountered in fundamental science, along with the conceptual relations between them: determinism, locality, stability, symmetries, conservation laws, and variation principles. The book shifts the focus away from causal relations between individual events (or properties of events) to the more general causal constraints found in science. This chapter discusses the main contending philosophical accounts of causation and the key issues they raise, including regularity theories (also known as Humean theories), the counterfactual account advanced by David Lewis, process accounts, probabilistic accounts, and interventionist or manipulation accounts. It also provides an overview of determinism, locality, stability, symmetries, conservation laws, and variation principles, along with causal asymmetry and the mutuality of causal relations.

Optimal sound-absorbing structures

Absorption by design, with minimal sample thickness allowed by the law of nature, can now be realized by using a design recipe that incorporates the causal constraint of acoustic response as a crucial element.

H∞Controller Design for Asynchronous Multirate Sampled-Data Systems

This paper considers the analysis and synthesis of a linear discrete asynchronous multirate sampled-data system. AnH∞controller based on an observer is proposed, which guarantees the stability of the closed system and makes theH∞norm of the closed system less than a given attenuation level. To improve the performance further, a tradeoff strategy is applied. That is, the exogenous signals sampled at different rates are lifted to an appropriate signal rate, while the endogenous signals are not lifted for avoiding the causal constraint and the dimension multiplied again. The controller is obtained by solving the corresponding matrix inequality, which can be calculated by Matlab. Finally, an example is presented to demonstrate the validity of these methods.