State Space Concept Research Articles

Role of Multistate Models to Predict Patency, Limb Salvage, and Survival: New Concepts to Analyse Data in Peripheral Arterial Disease

In peripheral arterial disease, patency, limb salvage, and survival rates are mostly reported using Kaplan-Meier analyses. When comparing different revascularisation techniques, these methods have limitations in analysing complex patient flows over time. This study aimed to present, illustrate, and discuss new concepts based on multistate models of analysing outcome parameters in peripheral arterial disease. Previously published data from a single centre, randomised controlled trial (RCT) with 218 cases that underwent either vein bypass surgery (bypass group, n = 109) or nitinol stent angioplasty (stent group, n = 109) of long femoropopliteal lesions were re-analysed using non-homogeneous Markov models. A step by step description of the concepts of states, state space, definitions, and illustration of transition probability curves as well as the benefits of multistate models is given. The RCT was registered at ISRCTN.com (ISRCTN18315574). Transition probability curves over time showed similar patterns in the bypass and stent groups. Significant differences in the transition probabilities were found for transitions from primary patency as well as secondary patency to end of patency. The transition probability for patients with preserved primary patency at 24 months who moved to end of patency at 48 months was 19.9% in the stent group vs. 6.4% in the bypass group (p < .001). The proposed method can answer important questions, such as: Did patients after femoropopliteal stenting with preserved primary patency at two years lose their patency more quickly within the following years compared with bypass surgery? and Did stent patients after a re-intervention to maintain patency at one year lose their patency more quickly compared with bypass surgery within the following years? Completely new research questions can now be raised and answered to optimise treatment and follow up strategies; this might lead to better identification of subgroups at higher risk of clinical deterioration following revascularisation procedures.

Assessing Efficiency in Artificial Neural Networks

The purpose of this work was to develop an assessment technique and subsequent metrics that help in developing an understanding of the balance between network size and task performance in simple model networks. Here, exhaustive tests on simple model neural networks and datasets are used to validate both the assessment approach and the metrics derived from it. The concept of neural layer state space is introduced as a simple mechanism for understanding layer utilization, where a state is the on/off activation state of all neurons in a layer for an input. Neural efficiency is computed from state space to measure neural layer utilization, and a second metric called the artificial intelligence quotient (aIQ) was created to balance neural network performance and neural efficiency. To study aIQ and neural efficiency, two simple neural networks were trained on MNIST: a fully connected network (LeNet-300-100) and a convolutional neural network (LeNet-5). The LeNet-5 network with the highest aIQ was 2.32% less accurate but contained 30,912 times fewer parameters than the network with the highest accuracy. Both batch normalization and dropout layers were found to increase neural efficiency. Finally, networks with a high aIQ are shown to be resistant to memorization and overtraining as well as capable of learning proper digit classification with an accuracy of 92.51%, even when 75% of the class labels are randomized. These results demonstrate the utility of aIQ and neural efficiency as metrics for determining the performance and size of a small network using exemplar data.

Safety-Critical Control Systems [About this Issue

This issue of <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">IEEE Control Systems</i> includes one feature and one lecture note. In the feature, “Runtime Assurance for Safety-Critical Systems: An Introduction to Safety Filtering Approaches for Complex Control Systems” <xref ref-type="list-item" rid="list-itemA1" xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">[A1]</xref> , authors Kerianne L. Hobbs, Mark L. Mote, Matthew C.L. Abate, Samuel D. Coogan, and Eric M. Feron provide an introductory tutorial of runtime assurance (RTA) concepts and their role in ensuring safety of complex control systems. Assuming an undergraduate-level understanding of control theory and state-space concepts, this article provides theory and examples for RTA architectures, four types of RTA approaches, and a number of systems engineering and practical considerations for employing RTA in safety-critical, cyberphysical systems. In the “Lecture Notes” column, “The Prandtl-Ishlinskii Hysteresis Model: Fundamentals of the Model and Its Inverse Compensator,” <xref ref-type="list-item" rid="list-itemA2" xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">[A2]</xref> Mohammad Al Janaideh, Mohammad Al Saaideh, and Xiaobo Tan introduce the mathematical formulations of the Prandtl–Ishlinskii (PI) and Generalized PI (GPI) hysteresis models as well as their analytical inverses. These models can effectively characterize hysteresis nonlinearities in various systems, especially smart-material actuators, and their inverses can be used in feedforward compensation to mitigate the effect of hysteresis. Numerical examples of the PI and GPI models as well as their analytical inverses are also included in the article. The intended audience includes graduate students and researchers from academia and industry interested in hysteresis modeling and compensation.

The Art of the State [From the Editor

Deep learning is impacting control in many ways, if not all deep. For more than a decade, it has reinstated the state-space concept as a central and unifying modeling principle. The magical equation <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">x+ = f</i> ( <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">x, u</i> ) currently dominates IEEE Control Systems Society publications, workshops, and conferences. Once confined to specialized circles of dynamic programming and nonlinear control, it has emerged over the last decade as a lingua franca shared by roboticists, optimizers, machine learners, computer programmers, and pretty much every scientist upgraded with the adjective “computational.” It celebrates the definite victory of computation over modeling in science and engineering.

Геополитика как концептуальная парадигма содержания и сущности государства и права

Introduction: the dominance of liberal ideology in modern jurisprudence eliminates the concept of an exclusive state and legal space. Under the basic postulates of theoretical geopolitics, on the contrary, the formation and development of any viable state organism occur by linking it to a certain part of the earth’s surface and is determined by its geographical properties. The subject of the paper is the study of the impact of geopolitical factors on the state and legal organization of countries and peoples. Its purpose is to establish the degree of conditionality of the internal legal order of states by the properties of spatial localization of the peoples forming them. Methods: the methodological framework for the research was a set of methods of scientific cognition, among which the dialectical method and the civilizational approach took the main place in the systematic analysis of the main trends in the development of sovereign statehood in historical retrospect and in the modern world. Results: modern jurisprudence and positive law, including international law, are increasingly correlated with liberal ideology, claiming the universality of its values and meanings and their spread on a global scale, which leads to an increasing weakening of sovereignty, chaos, and anomie in the internal life of states and international relations. Conclusions: in the current conditions, the law cannot act as a “measure of all things”. It should be exhaustively put at the service of geopolitics, helping the state, claiming real sovereignty, to implement such a strategy for the development of its own and surrounding space, which would allow it to extract the greatest positive results from its geographical structure and achieve natural borders in the further development, thereby adequately defining the place of existence and development of the state-forming people.

Comparative analyses of electrical circuits with conventional and revisited definitions of circuit elements: a fractional conformable calculus approach

PurposeThe purpose of this paper is to comparatively analyze the electrical circuits defined with the conventional and revisited time domain circuit element definitions in the context of fractional conformable calculus and to promote the combined usage of conventional definitions, fractional conformable derivative and conformable Laplace transform.Design/methodology/approachThe RL, RC, LC and RLC circuits described by both conventional and revisited time domain circuit element definitions has been analyzed by means of the fractional conformable derivative based differential equations and conformable Laplace transform. The comparison among the obtained results and those based on the methodologies adopted in the previous works has been made.FindingsThe author has found that the conventional definitions-based solution gives a physically reasonable result unlike its revisited definitions-based counterpart and the solutions based on those previous methodologies. A strong agreement to the time domain state space concept-based solution can be observed. The author has also shown that the scalar valued solution can be directly obtained by singularity free conformable Laplace transform-based methodology unlike such state space concept based one.Originality/valueFor the first time, the revisited time domain definitions of resistance and inductance have been proposed and applied together with the revisited definition of capacitance in electrical circuit analyses. The advantage of the combined usage of conventional time definitions, fractional conformable derivative and conformable Laplace transform has been suggested and the impropriety of applying the revisited definitions in circuit analysis has been pointed out.

Comprehensive Evaluation of Weapon Equipment Systems Operational Effectiveness Based on State Space Concept

In recent years, there are many researches on combat test of weapon equipment systems. However, in the process of comprehensive effectiveness evaluation, there are some shortcomings in the construction of index system, such as index redundancy, experts subjective weighting, which lead to the lack of objectivity and scientificity. Focusing on the objective state of the evaluated object, this paper puts forward an idea of comprehensive evaluation in the efficiency state space (ESS), and uses intelligent data processing method based on principal component analysis to examine the correlation of the underlying indicators of the evaluation index system (EIS), and attempts to conduct a comprehensive evaluation on this basis. Finally, we give the comparison the corresponding new results with the original evaluation results in the references. The data show that comprehensive evaluation under ESS can reduce efficiency calculation dimension from10 to 3. The final efficiency ranking is slightly different from that in the reference, but is much more rational and convincing.

Exact frequency domain method for the analysis of scattering from multilayer bi-anisotropic cylindrical structures.

Bi-anisotropic materials have enormous and interesting applications in electromagnetic (EM) engineering. In this study, based on the state space concept, an exact and rigorous analysis of EM propagation and scattering from multilayer bi-anisotropic cylindrical structures of the general case is proposed. In comparison to the other commonly used methods in the literature, the presented method reveals a faster and more accurate analytical framework. The similar works mostly presented approximated and numerical methods for the analysis of cylindrical structures containing bi-isotropic and/or anisotropic materials as special bi-anisotropic cases. Throughout the study, the geometrical specifications and the EM excitations are chosen based on practical considerations. Since the multilayer composite is practical especially for the realization of the inhomogeneous material, the proposed approach is applied to analyze inhomogeneous bi-anisotropic cylindrical structures with more degrees of freedom in manipulation of EM waves. Our results depict an excellent conformity to the other possible solutions to compute scattering from bi-anisotropic cylindrical configurations. The mentioned comprehensiveness is one of the main advantages of our work. The suggested approach can be used as a basic step for future research related to the analysis of forward and inverse scattering problems of practical types of cylindrical structures made by complex media.

Levy solution for bending response of FG carbon nanotube reinforced plates under uniform, linear, sinusoidal and exponential distributed loadings

A new analytical approach for bending response of functionally graded single-walled carbon nanotube (FGCNT) reinforced plate resting on double-layered elastic foundations in thermal environments is presented based on Levy and Navier types solutions. The distribution of the carbon nanotubes is varied through the plate thickness in accordance with a modified power law. Four types of carbon nanotube distributions are considered. The four edges of the plate are simply supported for Navier method, whereas for Levy method, two opposite only of them are simply supported and the other ones are arbitrary. The present FGCNT plate is subjected to uniform, linear, sinusoidal or exponential distributed loadings. A refined shear deformation plate theory with four unknown functions is employed to obtain the closed form solution. The four coupled governing partial differential equations are derived utilizing Hamilton’s principle. Applying Levy solution and then the state space concept to the governing equations, a nonhomogeneous first-order linear ordinary differential system with constant coefficients is obtained. The solution of the homogeneous system (homogeneous solution) is obtained by using the matrix method. While, the method of undetermined coefficients is applied to find the particular solution of the nonhomogeneous linear system. The results obtained by Navier and Levy methods are compared with available results in the literature. Several examples are discussed for various values of the foundation stiffness, CNT volume fraction, various types of plate geometries, CNT distributions, external applied loads and boundary conditions.

Investigation of multidimensional control systems in the state space and wavelet medium

The notions are introduced of “one-dimensional-point” and “multidimensional-point” automatic control systems. To demonstrate the joint use of approaches based on the concepts of state space and wavelet transforms, a method for optimal control in a state space medium represented in the form of time-frequency representations (maps), is considered. The computer-aided control system is formed on the basis of the similarity transformation method, which makes it possible to exclude the use of reduced state variable observers. 1D-material flow signals formed by primary transducers are converted by means of wavelet transformations into multidimensional concentrated-at-a point variables in the form of time-frequency distributions of Cohen’s class. The algorithm for synthesizing a stationary controller for feeding processes is given here. The conclusion is made that the formation of an optimal control law with time-frequency distributions available contributes to the improvement of transient processes quality in feeding subsystems and the mixing unit. Confirming the efficiency of the method presented is illustrated by an example of the current registration of material flows in the multi-feeding unit. The first section in your paper.

METHODOLOGY OF EVALUATING THE EFFICIENCY OF INFORMATION SUPPORT FOR DECISION-MAKING IN THE MANAGEMENT OF COMPLEX DYNAMIC OBJECTS

Abstract. Objectives The process of managing complex dynamic objects and systems is inevitably connected with the problem of the effectiveness of providing qualitative support information for making managerial decisions. The creation and application of an information system (IS) makes it results in a need to evaluate its effectiveness. Methods The article presents a methodology for evaluating the effectiveness of information systems in solving problems related to the management of complex dynamic objects. The content of the functional information system quality criteria is specified. Results Efficiency and quality indicators of an information system oriented towardsthe analysis of data related to information processing problems are substantiated. It is suggested that the necessary and sufficient condition for evaluating the effectiveness of an information system is the dimensionality of its indicator. A comparative analysis of variants of the solution is presented on the basis of their direct ranking, taking into account the significance of the scalar integral quality indicator. The transition to a vector indicator, whose elements are partially derived from the system’s own quality indicators, each of which can have an independent value for the subsequent level of the hierarchy, is indicated. Conclusion The need to take into account the partial indicators leads to specific methods for analysing and synthesising systems on the basis of a multi-criteria approach based on the state space concept. The content of the quality criteria for the information systems is specified in the article. A developed methodology for evaluating the effectiveness of information systems in solving problems relating to the management of complex dynamic objects, based on multi-criteria optimisation, is presented. Thedeveloped generalised information system quality indicator is justified. On the basis of the state space concept, it is possible to move away from the generally unsuitable scalar integral quality criterion of information systems to the vector of eigenvalues.

Size-dependent vibration of bi-directional functionally graded microbeams with arbitrary boundary conditions

In this paper, the free vibration behaviour of bi-dimensional functionally graded (BDFG) microbeams under arbitrary boundary conditions (BCs) is studied. Based on the frame work of the modified couple stress theory and Hamilton's principle, governing equations of motion are developed for the BDFG microbeams using a quasi-3D theory. The formula then can be reduced to a higher-order beam theory (HOBT) of conventional functionally graded (FG) microbeams with the material properties varying along the thickness direction only. Two types of BDFG microbeams with different patterns of material volume distribution are considered. The material properties used in this study are assumed to vary exponentially along both longitudinal and thickness directions of microbeams. Based on the state-space concept, the governing equations are solved for natural frequencies and vibration mode shapes of microbeams under various BCs. The effects of material distribution, geometric parameters and BCs are also investigated to examine the size-dependent behaviour of BDFG microbeams.

A novel time integration formulation for nonlinear dynamic analysis

To solve the linear and nonlinear dynamic equation of motion, a family of explicit higher-order time integration algorithms is presented. The differential transformation method in conjunction with the state–space concept is used. In this study, four members of this family are considered thoroughly. To validate the performance of the new algorithms, comparison studies are accomplished with the well-known time integration schemes. By solving some linear and nonlinear dynamic problems, the merits of the authors' formulations will be clearly demonstrated.

Mathematical Modelling of Translation and Rotation Movement in Quad Tiltrotor

Quadrotor as one type of UAV (Unmanned Aerial Vehicle) is an underactuated mechanical system. It means that the system has some control inputs is lower than its DOF (Degrees of Freedom). This condition causes quadrotor to have limited mobility because of its inherent under actuation, namely, the availability of four independent control signals (four-speed rotating propellers) versus 6 degrees of freedom parameterizing quadrotor position or orientation in space. If a quadrotor is made to have 6 DOF, a full motion control system to optimize the flight will be different from before. So it becomes necessary to develop over actuated quad tiltrotor. Quad tiltrotor has control signals more than its DOF. Therefore, we can refer it to the overactuated system. We need a good control system to fly the quad tiltrotor. Good control systems can be designed using the model of the quad tiltrotor system. We can create quad tiltrotor model using its dynamics based on Newton-Euler approach. After we have a set of model, we can simulate the control system using some control method. There are several control methods that we can use in the quad tiltrotor flight system. However, we can improve the control by implementing a modern control system that uses the concept of state space. The simulations show that the quad tiltrotor has done successful translational motion without significant interference. Also, undesirable rotation movement in the quad tiltrotor flight when performing the translational motions resulting from the transition process associated with the tilt rotor change was successfully reduced below 1 degree.

The Analysis of the State Space of Management Process in the Industry Applying Expert Systems

AbstractThe article includes analysis of expert system application possibilities in the environment of production processes control. Such concepts as artificial intelligence, expert system, intellectual factor, state space were used. The object of the research consisted of the mechanism of controlling an enterprise (manager). These mechanisms were analysed from the point of view of state space. The graph method was used to visualize information presentation. Analysis of control processes of an enterprise was carried out by determination of their state space. The concept of state space itself is completed with numerous measurement values (parameters) under influence of which the process of task solution takes place. Moreover, the concept of static and dynamic elements of state space of the control system is applied. It was shown that dynamic elements enable the quality presentation of space, which without including other restrictions leads to extension of its impact, which confirms that a given system has an intelligent factor.

Levy solution for bending analysis of functionally graded sandwich plates based on four variable plate theory

In the present study, static analysis of a functionally graded sandwich plate with two opposite simply supported edges is studied using a four variable refined plate theory. The core of sandwich plate is assumed isotropic and material properties of face layers are assumed graded through thickness direction by the power law. Displacement fields are defined by using the four variable plate theory. Equilibrium equations of the sandwich plate are obtained using virtual work principle. Levy type solution with state space concept is used to derive governing equations. The results of deflection, normal and shear stress of uniformly loaded functionally graded square sandwich plates with two opposite simply supported edges are presented. The accuracy of the solution is verified by comparing it with available results in the literature.

A Model of Early Motivational States and Their Uses

A model of early development of motivational states is proposed. The states are modeled in terms of modern concepts of state space and are physically realized by long-term-potentiation (LTP)-based neural circuits. The basic idea is to assume existence of libido and aggression instincts that would receive single sensory stimulus and induce capabilities for fight-or-flight, freeze or run, etc. The libido state may lead to happiness, contentment, or activities such as dance or play, imitation of observed behavior and action of others, and engagement in learning by trial and error.Enhancement of two motor skills are presented: responding more quickly in time and delivering a larger force of contact. This is a simple example of how the perception system, the motor system and the motivation system interact. A one-degree-of-freedom second-order mechanical system is modified by a first-order neural facilitator or compensator.The tit-for-tat phenomenon in force escalation is also modeled. The model includes tactile sensors for the measurement of a known force applied to a human finger, afferent transmission of the sensed force to the brain, storage of the perceived force, recovery of the stored force from memory, and efferent transmission of the force to the finger. The situation may change based on perception of more adversaries discouraging retaliation and encouraging resort to withdrawal and / or retreat.

Centralized controller design using state space concept

This paper presents a method for finding the controller parameters for a specific case of multi input multi output (MIMO) system. The focus of this paper is to obtain a simplified centralized PID tuning procedure using Falb’s row by row decoupling (RRDP) concept. Controller settings for zero order, first order and second order systems with different closed loop specifications have been obtained. Suitable examples are discussed to demonstrate the simplicity and effectiveness of the proposed method.

Hygrothermal deformation of orthotropic nanoplates based on the state-space concept

This paper deals with the investigation of the effect of hygrothermal conditions on the bending of nanoplates using Levy type solution model employing the state-space concept. The nanoplates are assumed to be subjected to a hygrothermal environment. The two-unknown function plate theory is used to derive the governing differential equations on the basis of Eringen's nonlocal elasticity theory. The governing equations contain the small scale effect as well as hygrothermal and mechanical effects. These equations are converted into a set of first-order linear ordinary differential equations with constant coefficients. Analytical solution of bending response for nanoplates under combinations of simply supported, clamped and free boundary conditions is obtained. Comparison of the results with those being in the open literature is made. The influences played by small scale parameter, temperature rise, the degree of moisture concentration, boundary conditions, plate aspect ratio and side-to-thickness ratio are studied.

Levy-type solution for bending of single-layered graphene sheets in thermal environment using the two-variable plate theory

Levy-type solution model is employed to demonstrate the bending response of single-layered graphene sheets subjected to a temperature field as well as external mechanical load. On the basis of Eringen׳s nonlocal elasticity equations incorporated with the two-variable plate theory, the governing differential equations of the thermomechanical response are derived by using the principle of virtual displacement. These equations are converted into a set of first-order linear ordinary differential equations with constant coefficients. The general solution of these equations can be obtained by using the state-space concept. Combinations of simply supported, clamped and free boundary conditions are considered. Comparison of the results with those being in the open literature is made. Numerical results are presented for rectangular sheets with different edge conditions, plate aspect ratios and nonlocal coefficient.