Concept Of Stability Research Articles

Linear and nonlinear investigations of the impact of chemical reaction on the thermohaline convection in a permeable layer saturated with Casson fluid

In this effort, the consequence of chemical reaction on the thermohaline convection in a permeable layer containing Casson fluid is inspected utilizing both linear and nonlinear stability procedures. To model the momentum equation, the Casson fluid version of Darcy's law is utilized. Applying the linear stability concept, the situation for the start of stationary and oscillatory pattern of convective motion is obtained, whereas the convective heat and mass transferences are determined using nonlinear stability theory. It is found that the oscillatory type of convective flow is probable only if the evaluation of the solutal Rayleigh–Darcy number is less than zero. The effect of the chemical reacting factor, the Casson factor, the Lewis number, and the solutal Rayleigh–Darcy number is to hurry the start of convection toward both stationary and oscillatory styles of convection and also surge the size of the convective cells. The convective heat and mass transfers enhance with increasing the Casson factor, the solutal and thermal Rayleigh–Darcy numbers while both decrease with enhancing the heat capacity quotient. The effect of chemical reacting factor is to increase the mass transmission in the system, while it has no effect on the heat transmission. It is also noted that the convective heat and mass transfers in the system enhance nearly 5.4% and 3.8%, respectively, with a 50% increase in the value of Casson factor.

Why rights should not be considered (entirely) constricted and why identities are not exactly imagined: A reply to Alma Begicevic and Jennifer Balint

Abstract In their recent article “Constricted Rights and Imagined Identities: Peace and Accountability Processes and Constitution-Making in Bosnia and Herzegovina,” Alma Begicevic and Jennifer Balint argue that underlying reasons for the seemingly sudden establishment of the complex constitutional arrangements in Bosnia and Herzegovina (BH) are associated with the abrupt adoption of the Dayton Peace Agreement and its Annex IV (the Constitution of BH) that introduced the ethnoterritorial setup and the lack of accountability of the neighboring countries for the atrocities committed during the Bosnian War. As a consequence, the country cannot effectively (re)construct a nation state and, instead, suffers from a lack of homogeneity. Moreover, post-conflict institutional and procedural arrangements appear to be comparatively uncharted territory. This article scrutinizes and counters these claims with the thesis that territorial accommodation of differences is a rather frequent approach in fragmenting systems with competing identities. To substantiate the thesis, the article draws on the concepts of cohesion and stability linked to adaptiveness and coordination. It then analyzes the role of the power ratio during the Bosnian War and the internal building blocks that contributed to the ethnoterritorial setup. Finally, the article focuses on the concept of equality in complex systems linked to mutual respect, solidarity, and trust to analyze the necessity for plural equality in BH.

From Classroom to Portfolio: Examining the Link Between Financial Education, Financial Literacy, and Risk-taking

This paper examines a panel dataset spanning the years 2010 to 2020 across ten countries, investigating the intricate relationship between financial assets and financial literacy. Two prominent trends surface:First, an intriguing inverse association is observed between higher rates of tertiary education attainment within a nation's population and individual financial assets. Second, an upsurge in the employment rate among individuals aged 25-64 corresponds with a decline in individual financial assets. These findings defy conventional research and call for comprehensive exploration within the framework of economic principles and broader economic awareness. As educational attainment and employment rates rise, heightened labor market competition, especially among individuals holding undergraduate or advanced degrees, leads to relatively reduced wages for those with similar qualifications, impacting their financial assets. Furthermore, this study corroborates that while increased income aligns with greater risk aversion, risk preferences display dynamic fluctuations over time and in response to personal experiences, contradicting neoclassical economic theory's concept of perfect stability. These findings underscore the necessity for a nuanced understanding of financial behavior. In summary, this research challenges established assumptions concerning the determinants of individual financial assets, highlighting the significance of multifaceted socio-economic variables and evolving risk perceptions in comprehending contemporary financial behaviors.

First/second-order predefined-time convergent ZNN models for time-varying quadratic programming and robotic manipulator application

Zeroing neural network (ZNN) model, an important class of recurrent neural network, has been widely applied in the field of computation and optimization. In this paper, two ZNN models with predefined-time convergence are proposed for the time-varying quadratic programming (TVQP) problem. First, in the framework of the traditional ZNN model, the first-order predefined-time convergent ZNN (FPTZNN) model is proposed in combination with a predefined-time controller. Compared with the existing ZNN models, the proposed ZNN model is error vector combined with sliding mode control technique. Then, the FPTZNN model is further extended and the second-order predefined-time convergent ZNN (SPTZNN) model is developed. Combined with the Lyapunov method and the concept of predefined-time stability, it is shown that the proposed FPTZNN and SPTZNN models have the properties of predefined-time convergence, and their convergence time can be flexibly adjusted by predefined-time control parameters. Finally, the proposed FPTZNN and SPTZNN models are compared with the existing ZNN models for the TVQP problem in simulation experiment, and the simulation experiment results verify the effectiveness and superior performance of the proposed FPTZNN and SPTZNN models. In addition, the proposed FPTZNN model for robot motion planning problem is applied and successfully implemented to verify the practicality of the model.

Fractional insights into Zika virus transmission: Exploring preventive measures from a dynamical perspective

Abstract Mathematical models for infectious diseases can help researchers, public health officials, and policymakers to predict the course of an outbreak. We formulate an epidemic model for the transmission dynamics of Zika infection with carriers to understand the intricate progression route of the infection. In our study, we focused on the visualization of the transmission patterns of the Zika with asymptomatic carriers, using fractional calculus. For the validity of the model, we have shown that the solutions of the system are positive and bounded. Moreover, we conduct a qualitative analysis and examine the dynamical behavior of Zika dynamics. The existence and uniqueness of the solution of the system have been proved through analytic skills. We establish the necessary conditions to ensure the stability of the recommended system based on the Ulam–Hyers stability concept (UHS). Our research emphasizes the most critical factors, specifically the mosquito biting rate and the existence of asymptomatic carriers, in increasing the complexity of virus control efforts. Furthermore, we predict that the asymptomatic fraction has the ability to spread the infection to non-infected regions. Furthermore, treatment due to medication, the fractional parameter or memory index, and vaccination can serve as effective control measures in combating this viral infection.

Response to stress via underlying deep gene regulation networks

Exposure of cells to non‐optimal growth conditions or to any environment that reduces cell viability can be considered as a stress. In this paper, we are going to highlight the main factors that determine the danger of stress to a cell considered as a biochemical system. To this end, we introduce a new mathematical concept of biosystem stability, where we take into account a signal transduction by deep gene networks. Using this concept and known results on approximations by deep networks, we find asymptotic estimates of the size and the depth of gene regulation networks that define the stress response. We propose a new algorithm to find the gene network approximating a prescribed output. It allows us, with the help of Kolmogorov ‐entropy and the deep neural network theory, to estimate the number of genes involved in regulation of responses on a stress (for example, a heat shock). We show that the main factors that increase the sensitivity of the systems with respect to a stress are the number of biochemical network parameters affected by the stress and sensitivities of kinetic rates with respect to these parameters.

A Study on Some Properties for Weak Stability of Non-Autonomous Discrete Dynamical Systems

The interest for non-autonomous discrete dynamical systems has been increasing in recent years, because they are adequate to tell of real activities. For examples, when the mapping is disturbed in each iteration because of external factors, or model of some phenomena in physics, biology and economy, in specific, the population of human and weather forecasting, plus to solve problems generated in mathematics. In mathematics, stability theory addresses the stability of solutions of trajectories of dynamical systems under small perturbations of initial conditions. Besides that, the topological dynamics is the main method used in this paper, since we studied the non-autonomous discrete dynamical systems on a topological space. Next, we present a conception of weak stability (stableness) of non-autonomous discrete dynamical systems (NADDS). We evaluate a collection of weak stable points, and survey the connection among weak stableness and shadowing property. We also consider the connection among weak stableness of a non-autonomous discrete dynamical system and its induced system. In conclusion, the results of this paper will provide some helps in the modelling of a general dynamical system.

Theoretical and methodological basis of the concept of sustainable development of an enterprise

Methods. The theoretical, scientific and methodological basis is the system approach, which allows to consider an enterprise as a system that functions in a changing external environment and is influenced by external and internal factors that affect the system’s sustainability, and makes the basis for understanding the essence and prerequisites for sustainable and resilient development of an enterprise. The process approach is the basis for developing a structural and logical scheme of the process of enterprise development as an economic system. The methods of analysis and synthesis allowed to identify possible levels of development of economic systems for the study of sustainable development of enterprises. Factor analysis was used to identify the problems associated with ensuring the sustainable development of enterprises in the conditions of Economy 5.0. Results. The article examines the theoretical and methodological foundations of the concept of sustainable development of an enterprise. Different approaches to the definition of the concept of development are distinguished, in particular evolutionary, synergistic, genetic, and conflictological. The essence and features of enterprise development as an economic system are considered. The author’s view on the development process in the form of a structural and logical scheme is proposed. Such components as the state of the economic entity, internal and external determinants, results, sources and causes of development are allocated. The differences between the concepts of stability and sustainability of systems are investigated. The specifics of sustainable development of an enterprise in comparison with sustainable development, which is, in particular, a broader concept with an emphasis on economic, social and environmental aspects, are determined. Conclusions are drawn regarding the multidimensional nature of approaches to understanding enterprise development and the growing role of the concept of sustainable development in the context of Economy 5.0. Novelty. Different approaches to defining the concept of sustainable development are pointed out, in particular, evolutionary, synergistic, genetic, and conflictological. The author’s view on the development process is proposed. Practical value. The results of the study are of theoretical and practical importance for developing the models of innovation-oriented transformation of domestic enterprises on the basis of sustainable development, taking into account global technological trends.

Political science meets physical science: The shared concept of stability

Abstract A biophysical chemist and a political scientist team up to explore striking parallels between the requisites of “stability” and the causes of instability within both the cellular/molecular world of biophysical chemistry and the world of social and political organization of self-assembled, societal structures, such as sovereign states and institutions. The structure, function, and organizational similarities of such parallelisms are particularly noteworthy, given that human agency introduces greater contingency in the sociopolitical world than do the “laws of Nature” in the natural-scientific world. In this perspective piece, we critically identify and analyze these parallels between the natural and the social realms through the prism of the shared concept of stability, including causal factors that embrace the full “stability spectrum” from instability to stability. This spectrum includes the crucial bridging, time-dependent, intermediate, kinetic state of “metastability.” Our analyses reveal that, in the microscopic/molecular world of the physical sciences, the thermodynamic and kinetic characterizations of the stabilities and transformations between physiochemical “states” exhibit cognate properties and features in the macroscopic world of sociopolitical arenas in ways that reflect a greater than traditionally assumed continuity between Nature and society. Select examples from the natural and social realms are presented and elaborated on to illustrate these parallelisms, while underscoring the striking similarities in their functional consequences.

Impulsive Controllers Design for the Practical Stability Analysis of Gene Regulatory Networks with Distributed Delays

This paper studies gene regulatory networks (GRNs) with distributed delays. The essential concept of practical stability of the genes is introduced. We investigate the problems of practical stability and global practical exponential stability of the GRN model under an impulsive control. New practical stability criteria are proposed by designing appropriate impulsive controllers via the Lyapunov functions approach. In the design of the impulsive controller, we consider the effect of impulsive perturbations at fixed times and distributed delays on the stability of the considered GRNs. Several numerical examples are also presented to justify the proposed criteria.

STABILITAS PARAMETRIK HASIL 14 GENOTIPE TOMAT (Solanum lycopersicum L.) DI EMPAT LINGKUNGAN DATARAN RENDAH

This study aimed to obtain information stability results 14 tomato genotypes grown in four lowland locations using multiple methods of parametric stability analysis. The experiments were conducted at four locations, namely Purwakarta, Lombok, Tajur and Leuwikopo. Experiments at each location using Randomized Complete Block Design (RCBD) with three replications which replicates nested within location. The method used were Francis and Kannenberg, Wrickle ekovalens, Finlay and Wilkinson, Eberhart and Russel, Wrickle ekovalens and AMMI .
 Research carried out shows based on the concept of static stability using the method of Francis and Kannenberg and Russell Eberhart, who declared stable genotype were IPBT3, IPBT53 and IPBT78. Based on the concept of dynamic stability using Wrikle ekovalens and Finlay & Wilkinson methods, stable genotype were IPBT3, IPBT8, IPBT33, IPBT34, IPBT57, IPBT60, IPBT64 and Intan. IPBT3, IPBT33, IPBT34, IPBT60 and Intan as stable genotypes under AMMI methods.

Existence and stability of solution for a nonlinear Volterra integral equation with binary relation via fixed point results

The real-world problems that can be resolved by a dynamic mathematical model is an analogous form of a complex integral equation. In this article, we intend to exhibit the solution to a non-homogeneous, nonlinear Volterra integral equation endowed with an arbitrary binary relation utilizing the fixed point solution that is originally proved for a multivalued map and then reduced to a single valued self map. The results proved and the application demonstrated is an added asset to the present literature and can significantly contribute in determining the existence of a solution for a dynamic mathematical model in the form of a Volterra integral equation equipped with an arbitrary binary relation via fixed point findings. Furthermore, the stability of the solution of the Volterra integral equation is verified using the Hyers–Ulam stability concept.

Qualitative and Ulam–Hyres stability analysis of fractional order cancer-immune model

The primary objective of this study is to employ the novel fractional operator to investigate a mathematical model of cancer, specifically focusing on the dynamics of cancer cells when treated with a combination of IL-12 cytokines and an anti-PD-L1 inhibitor. We utilize nonlinear differential equations to represent this complex system. We aim to conduct a comprehensive mathematical analysis of the fractional-order tumor model using the Atangana–Baleanu–Caputo derivative. We intend to qualitatively and quantitatively assess the dynamics of the tumor-immune system to understand its real-world implications. We seek to establish the existence and uniqueness of solutions for our model using fixed-point theorems. We will analyze the stability of the system, verifying its equilibrium points through the Ulam–Hyres stability concept and demonstrating global stability using a Volterra-type Lyapunov function. We will explore the impact of the fractional operator on the dynamical system, employing the Atangana–Tufik scheme with a generalized Mittag-Leffler kernel and results are compared with Caputo fractional derivative. Finally, we will present numerical simulations using the proposed scheme to provide insights into the practical behavior of our model within the scientific community.

Robust limit cycle control for finite-time generation of sustained oscillations in nonlinear systems with mixed dead-zone and saturation

This paper suggests a novel limit cycle control technique, based on the finite-time stability scheme, for producing sustained oscillations in a class of nonlinear complex systems. The considered systems are constrained to input dead-zone and saturation simultaneously and suffer from non-vanishing perturbations due to model uncertainties, and external disturbances. For this purpose, an innovative sliding manifold is proposed based on the topology of the wanted limit cycle which provides the conditions for developing the finite time stability concept for limit sets. With the aid of the finite-time command filter and the cooperation of the sliding mode control (SMC) method with the backstepping technique, a robust controller is constructed which guarantees the finite-time convergence of phase trajectories of the closed-loop system toward the wanted limit cycle. This leads to the creation of sustained oscillations, with the desirable amplitude and frequency, in the system's output. The stability analysis is proved based on the Lyapunov approach through the set stability concept. Finally, the effectiveness of the suggested methodology is confirmed by a variety of simulations.

A Case Series of Distal Radius and Ulna Nonunion Treated with Minimal Surgical Intervention

Abstract Background We hypothesized a treatment guideline for ulna/radius nonunion after failed surgical treatment and propose to verify it in a prospective study. Herein, we report our preliminary findings and review the current trend. Methods Six patients who met the criteria were retrospectively investigated, and we further categorized “nonunion of both the radius/ulna” into four subcategories. For hypertrophic nonunion of the radius, but with stability maintained by a plate, we only reinforced the mechanical stability of the ulna (osteosynthesis, treatment option 1). In oligo- or atrophic nonunion of the radius with stability maintained by a plate, we added cancellous or tricortical bone grafts to the radius after osteosynthesis of the ulna (treatment option 2). In the presence of definitive pseudomotion of the radius (no stability), we performed revision osteosynthesis for the radius only, without (treatment option 3) or with bone graft (treatment option 4). Results Two, one, one, and two patients had corresponding treatment options of 1, 2, 3, and 4, respectively. At a mean postoperative time of 4.3 months, all radii and ulnas showed union. At the final follow-up, clinical outcomes in terms of the range of motion and VAS (visual analog scale)/DASH (disabilities of the arm, shoulder, and hand) scores were satisfactory. We are currently conducting a prospective trial to verify the hypothesized guidelines. For both types of radius/ulna nonunion, first, if the stability of the radius was good, we compared the final outcomes with or without revision osteosynthesis for the radius, in addition to osteosynthesis for the ulna. Second, if stability was absent in the radius, we compared the final outcomes with or without osteosynthesis of the ulna, in addition to revision osteosynthesis of the radius. Conclusions The treatment guidelines for rare nonunion after failed surgical treatment of both the distal radius/ulna were suggested according to the “concept of stability” based on the principles of fracture treatment. This hypothesis could be used to guide prospective studies of revision surgery for nonunion of both the radius and ulna. Level of Evidence Level IV, retrospective case series.

Stability in statutory kinship care: A grounded theory study of placement stability in Australia

This constructivist grounded theory study explored the concept of placement stability from the perspective of statutory kinship carers who self-identified as providing a stable kinship placement in Queensland, Australia. Twenty statutory kinship carers participated in semi-structured qualitative interviews. The study developed a substantive grounded theory of how Kinship Carers perceive a stable statutory kinship care placement and found six social processes that underpinned how the kinship carer felt, thought and acted. The core category was feeling connected. The five non-core categories were seeing the need, being constant, empathising with, championing for, and being aware and accepting of the kinship context. The study found no differences between familial and non-familial kinship carers perception of stability. It found that some of the categories were influenced when the kinship carer family identified as Australian Aboriginal or a preplacement relationship existed between the kinship carer and the child. The substantive theory developed by this study was applied to social worker practice in out-of-home care.

Minimax regret stability in the graph model for conflict resolution

In strategic conflicts, decision-makers (DMs) do not constantly make their best decisions, which makes room for DMs to feel regretful. In this context, this work proposes the Minimax Regret Stability within the graph model for conflict resolution (GMCR) for modelling and analysing conflicts, considering that DMs would feel regret for an unsatisfactory decision. This concept does not require knowledge about the opponent’s preference in bilateral conflicts. The aim of the new solution concept is to recommend a state as stable if there exists a policy recommending to stay at that state which minimizes the maximum regret of the DM for a given conflict horizon, where a policy specifies what action a DM must choose in every conflict state. In addition, we investigate the relations among the Minimax regret stability and other classical GMCR solution concepts. Following, the influence of the horizon on the stability of states is also studied. Finally, a truckers’ strike conflict was used to illustrate how the new solution concept can provide valuable strategic insights in real-life conflict situations.

Some problems of target approach for nonlinear control system at a fixed time moment

The game problem of target approach for nonlinear control system with a target set in a finite-dimensional phase space at a fixed time is studied. The problem is formulated and studied within the framework of concepts and constructions of the theory of positional differential games, created by N.N. Krasovskii and A.I. Subbotin in the second half of the 20th century. One of the central problems of the theory of positional differential games is the problem of calculating positional sets of uptake in convergence game problems. The paper investigates a key stability property in the theory of positional differential games, which is a characteristic of some closed sets in the space of positions of a controlled system that are convenient for the first player to conduct the game. It is important that this property is also characteristic for solvability sets in convergence problems: the inclusion of the concept of stability in research makes it possible to obtain analytical descriptions of solvability sets in some specific convergence problems and to develop algorithms for approximate calculation of the solution in a number of specific problems. Some modifications of the definition of a $u$-stable bridge in the considered convergence problem and a system of sets approximating the attainability set are given. Three specific problems on the convergence of mechanical systems are also presented, computer solutions are simulated, and graphical simulation results are presented.

Mean exit times as global measure of resilience of tropical forest systems under climatic disturbances-Analytical and numerical results.

Both remotely sensed distribution of tree cover and models suggest three alternative stable vegetation states in the tropics: forest, savanna, and treeless states. Environmental fluctuation could cause critical transitions from the forest to the savanna state and quantifying the resilience of a given vegetation state is, therefore, crucial. While previous work has focused mostly on local stability concepts, we investigate here the mean exit time from a given basin of attraction, with partially absorbing and reflecting boundaries, as a global resilience measure. We provide detailed investigations using an established model for tropical tree cover with multistable precipitation regimes. We find that higher precipitation or weaker noise increases the mean exit time of the forest state and, thus, its resilience. Upon investigating the transition times from the forest state to other tree cover states, we find that in the bistable precipitation regime, the size of environmental fluctuations has a greater impact on the transition probabilities from the forest state compared to precipitation.

Test of a full-scale two-story steel X-BRBF: Strong-axis instability of buckling restrained brace associated with out-of-plane bending of gusset connections

This paper presents tests and finite element analyses of a two-story, buckling-restrained braced frame (BRBF) with X-bracing configuration, called X-BRBF. The BRB used in this work is composed of a core plate sandwiched by a pair of the restraining member with bolts, called a sandwiched buckling restrained brace (SBRB). The weak-axis of the SBRB core that had a rectangular plate was positioned transverse to the dual-gusset plate connection and in-plane movement of the frame. The objectives of the frame test were to evaluate: (1) the seismic performance of SBRBs with a small width-to-thickness ratio of the core plate (i.e. 3), (2) the effects of free-edge stiffeners on the gusset and BRB stability, and (3) the BRB stability associated with the lateral torsional buckling (LTB) of the beam. The two-story X-BRBF subassembly had two test phases: all gusset connections had free-edge stiffeners in Phase 1 test, and freeedge stiffeners were removed from half of gusset connections in Phase 2 test. The X-BRBF in Phase 1 test exhibited good performance up to a second-floor drift of 1.6%, but in Phase 2 test the second-floor SBRB caused by LTB of the beam showed asymmetric instability about its strong-axis of the core plate at 1.6% second-floor drift. The other SBRB with no LTB of the beam showed one-side instability about its strongaxis at 2% second-floor drift (about 2.5% interstory drift). However, the strength degradation of the X-BRBF subassembly was not observed in the strong-axis instability of SBRBs, indicating an acceptable orientation of BRBs for eliminating a typical weak-axis buckling of BRBs together with out-of-plane bending of gusset plates. The strong-axis instability of SBRBs could be evaluated by using the BRB stability concept together with the measured out-of-plane deformation of gusset plates in Phase 2 test.