The Stability of the Systems with Command Saturation, Command Delay, and State Delay

This article presents the study of the stability of single-input and multiple-input systems with point or distributed state delay and input delay and input saturation. By a linear transformation applied to the initial system with delay, a system is obtained without delay, but which is equivalent from the point of view of stability. Next, using sufficient conditions for the global asymptotic stability of linear systems with bounded control, new sufficient conditions are obtained for global asymptotic stability of the initial system with state delay and input delay and input saturation. In addition, the article presents the results on the instability and estimation of the stability region of the delay and input saturation system. The numerical simulations confirming the results obtained on stability were performed in the MATLAB/Simulink environment. A method is also presented for solving a transcendental matrix equation that results from the process of equating the stability of the systems with and without delay, a method which is based on the computational intelligence, namely, the Particle Swarm Optimization (PSO) method.

Formalization of the meaning. Part 3. Formation of contexts

The previous parts of this article have attempted to begin describing an approach to building strong artificial intelli-gence based on sense of information. A model was proposed in which concepts were described through related points of view. The point of view was set as a context that changes the original description to its interpretation. It was shown that the meaningfulness of the interpretation can be judged by its adequacy to the memory of previous experience. The space of contexts is described, which defines a system of concepts that cover a certain subject area. In this part of the article, an algorithm is described that allows you to create an initial system of concepts based on the observable signs of phe-nomena, and move from it to the contexts corresponding to these concepts. For the space of contexts, a method for cre-ating concept codes is proposed, which allows concept codes to convey the system of their internal proximity, a com-parison with convolutional networks is made. Explanations of the proposed approach are considered on the example of training the visual cortex.

Improving the Response Performance of Anti-Surge Control Valve for Gas Compressors

Anti-surge control valves are used for the protection of gas compressors by opening to relief sudden pressures (surge) which could damage the compressor internals. It is of great importance that the response of the anti-surge valves to surge detection is swift and within a few seconds since a little delay could cause catastrophic damages to the compressor it is meant to protect. In this paper, a design modification was done on an existing anti-surge valve to improve its response time. The modified system was designed and implemented, installed, and commissioned on a mixed refrigerant compressor. The modified system was tested, and the response performance was recorded. Results obtained showed average percentage improvement of 86% to that of the initial system. Also, the response performance of the modified system was less than 3 seconds as compared to the initial set-up which averages 9 seconds. This is indeed a great improvement in comparison to the initial system.

Feedback and the emergence of structures in information systems.

The aim of the work is to find conditions under which a complex multifunctional system acquires a certain struc- ture and comes to a balanced state. The initial system, consisting of mutually influencing objects or processes, is modeled by a sign graph. Analysis of the degree of influence takes into account both the direct impact between neighboring peaks, and indirect, mediated through other objects. Examples are given and conditions are indicated under which, under the ac- tion of the mechanism of introducing feedbacks, an unbalanced initial graph of interactions comes to a stable two-class structure. Cases are shown when disturbances in a balanced graph, leading it out of this state, after the application of the feedback mechanism were leveled, and the system was stabilized. Both fully connected graphs and digraphs without cycles are investigated.

Hierarchical-environment-assisted non-Markovian and its effect on thermodynamic properties

We consider a microscopic collision model, i.e., a quantum system interacts with a hierarchical environment consisting of an auxiliary system and a reservoir. We show how the non-Markovian character of the system is influenced by the coupling strength of system-auxiliary system and auxiliary system-reservoir, coherence of environment and initial system-environment correlations. And we study the non-Markovianity induced by coherence of environment from the perspective of energy, further the relationship between information backflow and energy flux is obtained. Then we study the effect of non-Markovianity on thermodynamic properties. By studying the entropy change of system especially that from heat exchanges with the environment, we reveal the essence of entropy change between positive and negative values during non-Markovian evolution is due to the contribution of heat flux induced by coherence. And compared with the case of Markovian dynamics, we observe that the entropy production decreases in some specific time intervals under non-Markovian dynamics induced by the coupling strength. And this is different to the case of non-Markovianity caused by initial system-environment correlation, that we show the possibility of positive entropy production during the whole dynamics.

Dynamical decoupling with initial system-environment correlations

Dynamical decoupling (DD) technique is one of the most successful methods to suppress decoherence in qubit systems. In this paper, we studied a solvable pure dephasing model and investigated how DD sequences and initial correlations affect this system. We gave the analytical expressions of decoherence functions and compared the decoherence suppression effects of DD pulses in Ohmic, sub-Ohmic and super-Ohmic environments. Our results show that (1) The initial system-environment correlation will cause additional decoherence. In order to control the dynamic process of open quantum system more accurately and effectively, the initial correlation between the system and reservoir must be considered. (2) High frequency DD pulses can significantly reduce the amplitude of the decoherence function even in the presence of initial system-environment correlations.