Absolute Stability of Neutral Systems with Lurie Type Nonlinearity

The paper studies absolute stability of neutral differential nonlinear systems x ˙ ( t ) = A x t + B x t − τ + D x ˙ t − τ + b f ( σ ( t ) ) , σ ( t ) = c T x ( t ) , t ⩾ 0 $$ \begin{align}\dot x(t)=Ax\left ( t \right )+Bx\left ( {t-\tau} \right ) +D\dot x\left ( {t-\tau} \right ) +bf({\sigma (t)}),\,\, \sigma (t)=c^Tx(t), \,\, t\geqslant 0 \end{align} $$ where x is an unknown vector, A, B and D are constant matrices, b and c are column constant vectors, 𝜏 > 0 is a constant delay and f is a Lurie-type nonlinear function satisfying Lipschitz condition. Absolute stability is analyzed by a general Lyapunov-Krasovskii functional with the results compared with those previously known.

Inherent Stability of Multibody Systems with Variable-Stiffness Springs via Absolute Stability Theory

In this paper, the inherent stability problem for multibody systems with variable-stiffness springs (VSSs) is studied. Since multibody systems with VSSs may consume energy during the variation of stiffness, the inherent stability is not always ensured. The motivation of this paper is to present sufficient conditions that ensure the inherent stability of multibody systems with VSSs. The absolute stability theory is adopted, and N-degree-of-freedom (DOF) systems with VSSs are formulated as a Lur’e form. Furthermore, based on the circle criterion, sufficient conditions for the inherent stability of the systems are obtained. In order to verify these conditions, both frequency-domain and time-domain numerical simulations are conducted for several typical low-DOF systems.

From metaphor to computation: Constructing the potential landscape for multivariate psychological formal models

For psychological formal models, the stability of different phases is an important property for understanding individual differences and change processes. Many researchers use landscapes as a metaphor to illustrate the concept of stability, but so far there is no method to quantify the stability of a system’s phases. We here propose a method to construct the potential landscape for multivariate psychological models. This method is based on the generalized potential function defined by Wang et al. (2008) and Monte Carlo simulation. Based on potential landscapes we define three different types of stability for psychological phases: absolute stability, relative stability, and geometric stability. The panic disorder model by Robinaugh et al. (2019) is used as an example, to demonstrate how the method can be used to quantify the stability of states and phases, illustrate the influence of model parameters, and guide model modifications. An R package, simlandr, was developed to provide an implementation of the method.

Analysis and synthesis of single-input-single-output Lurie type systems via H∞ mixed-sensitivity

The goal of this paper is to present a different approach to the analysis of the absolute stability of Lurie type systems in the single-input-single-output (SISO) case using robust control theory. The proposed technique enables the design of controllers via [Formula: see text] mixed-sensitivity (S/KS/T), where, besides making the system absolutely stable, the performance problem can also be solved. In addition, it is also demonstrated that it is possible to make use of this new approach in time-delay Lurie type systems. Thus, through a new methodology, this work paves the way to the study of the absolute stability of multiple-inputs-multiple-outputs (MIMO) systems, aiming at a better generalization of the theory and enabling applications in other areas, such as neural networks. Examples, numerical simulations and application in Chua’s circuit are given to illustrate the results.

Estabilidad de los docentes curriculares de institutos privados reconocidos o adscriptos a la enseñanza oficial : en tiempos de normalidad y en el de la pandemia.

En tiempo de pandemia, el DNU Nº329/2020(B.O.,31/3/2020) del Poder Ejecutivo nacional se dictó en el marco de la emergencia sanitaria por el coronavirus y sus prórrogas decididas por el DNU Nº487/2020 (B.O.,19/5/2020) y el DNU Nº 624/2020 (B.O.,29/7/2020) prohibieron los despidos sin justa causa y por causas económicas y por fuerza mayor por el plazo de 60 días contados a partir de la fecha de su publicación en el Boletín Oficial, desde el 31 de marzo hasta el 29 de mayo de 2020, luego hasta el 28 de julio y más tarde hasta el 26 de setiembre de 2020. Se ha establecido un régimen de estabilidad propia o absolutapara todos los trabajadores privados a los que alcanzan esos DNU, incluidos los docentes privados de cualquier nivel, curriculares o no- pero pro tempore, porque es limitada al plazo de veda. La decisión del Poder Ejecutivo Nacional aparece como constitucional y convencional, adecuada a normas supra legales que él mismo cita y a otras ut supra referidas, como a la jurisprudencia de la CSJN y la CIDH. Pasada la emergencia y la vigencia del DNU, la incógnita está en si se volverá para todos los trabajadores privados en Argentina al sistema de estabilidad relativa impropia o se podrá pasar a una intermedia, como es la que acompaña a los docentes privados mencionados desde 1947, parecida a la del Estatuto de los Trabajadores español para el caso de despido improcedente, o laexcepción del DNU se volverá regla.ABSTRACT: In times of pandemic, DNU No. 329/2020 (BO, 3/31/2020) of the national Executive Power was issued within the framework of the health emergency caused by the coronavirus and its extensions decided by DNU No. 487/2020 (BO, 19 / 5/2020) and DNU No. 624/2020 (BO, 7/29/2020) prohibited dismissals without just cause and for economic reasons and force majeure for a period of 60 days from the date of its publication in the Official Gazette, from March 31to May 29, 2020, then until July 28 and later until September 26, 2020. A regime of own or absolute stability has been established for all private workers to those who reach these DNU, including private teachers of any level, curricular or not - but pro tempore, because it is limited to the closed period. The decision of the National Executive Power appears as constitutional and conventional, adequate to supra-legal norms that it cites itself and to other supra-referred ones, such as the jurisprudence of the CSJN and the IACHR. After the emergency and the validity of the DNU, the question is whether it will return for all private workers in Argentina to the system of improper relative stability or it will be possible to move to an intermediate one, such as the one that accompanies the private teachers mentioned since 1947, similar to that of the Spanish Workers' Statute in the case of unfair dismissal, or the exception of the DNU will become the rule.

Study on the Melting Temperature, the Jumps of Volume, Enthalpy and Entropy at Melting Point, and the Debye Temperature for the BCC Defective and Perfect Interstitial Alloy WSi under Pressure

The objective of this study is to determine the analytic expressions of the Helmholtz free energy, the equilibrium vacancy concentration, the melting temperature, the jumps of volume, enthalpy the mean nearest neighbor distance and entropy at melting point, the Debye temperature for the BCC defective, the limiting temperature of absolute stability for the crystalline state, and for the perfect binary interstitial alloy. The results obtained from the expressions are combined with the statistical moment method, the limiting condition of the absolute stability at the crystalline state, the Clausius–Clapeyron equation, the Debye model and the Gruneisen equation. Our numerical calculations of obtained theoretical results were carried out for alloy WSi under high temperature and pressure. Our calculated melting curve and relation between the melting temperature and the silicon concentration for WSi are in good agreement with other calculations. Our calculations for the jumps of volume, enthalpy and entropy, and the Debye temperature for WSi predict and orient experimental results in the future.

Anterograde fixation of inverted oblique medial malleolus fractures

Fractures of the medial malleolus are common, with avulsion being the main trauma mechanism. In simple transverse fractures, retrograde fixation with interfragmentary screws is the most common means of achieving anatomical reduction and absolute stability. However, greater attention must be paid in cases of inverted oblique fractures, which make traditional fixation difficult. We report a case in which anatomical reduction and stabilization were achieved using a reduction clamp and two headless compression screws placed anteriorly, resulting in a mechanically stable, safe and effective repair. Level of Evidence V, Therapeutic Studies; Expert Opinion.