Inequality Conditions Research Articles

Turing instabilities for three interacting species

In this paper, I prove necessary and sufficient conditions for the existence of Turing instabilities in a general system with three interacting species. Turing instabilities describe situations when a stable steady state of a reaction system (ordinary differential equation) becomes an unstable homogeneous steady state of the corresponding reaction–diffusion system (partial differential equation). Similarly to a well-known inequality condition for Turing instabilities in a system with two species, I find a set of inequality conditions for a system with three species. Furthermore, I distinguish conditions for the Turing instability when spatial perturbations grow steadily and the Turing–Hopf instability when spatial perturbations grow and oscillate in time simultaneously.

Robust Invariance Conditions of Uncertain Linear Discrete Time Systems Based on Semidefinite Programming Duality

This article proposes a novel robust invariance condition for uncertain linear discrete-time systems with state and control constraints, utilizing a method of semidefinite programming duality. The approach involves approximating the robust invariant set for these systems by tackling the dual problem associated with semidefinite programming. Central to this method is the formulation of a dual programming through the application of adjoint mapping. From the standpoint of semidefinite programming dual optimization, the paper presents a novel linear matrix inequality (LMI) conditions pertinent to robust positive invariance. Illustrative examples are incorporated to elucidate the findings.

Admissibility Analysis and Controller Design Improvement for T-S Fuzzy Descriptor Systems

In this paper, a stability analysis and the controller improvement of T-S fuzzy Descriptor system are studied. Firstly, by making full use of the related theory of fuzzy affiliation function and combining the design method of fuzzy Lyapunov function with the method of inequality deflation, a stability condition with wider admissibility and less system conservatism is proposed. The advantage of this method is that it is not necessary to ensure that each fuzzy subsystem is progressively stable. We also maximise the boundary of the derivatives of the affiliation function mined. Secondly, a PDC controller and a Non-PDC controller are designed, and the deflation conditions for the linear matrix inequalities of the two controllers are constructed. Finally, some arithmetic simulations and practical examples are given to demonstrate the effectiveness of the method studied in this paper, and the results obtained are less conservative and have larger feasible domains than previous methods.

Harnessing membership function dynamics for stability analysis of T-S fuzzy systems

The main goal of this paper is to develop a new less conservative linear matrix inequality (LMI) condition for the asymptotic stability of continuous-time Takagi-Sugeno fuzzy systems. A key advantage of this new condition is its independence from the bounds on the time-derivatives of the membership functions (MFs), a requirement that presents in the existing approaches. This is achieved by introducing a novel fuzzy Lyapunov function that incorporates an augmented state vector. Notably, this augmented state vector includes MFs and allows their dynamics to be integrated into the proposed LMI condition. This inclusion of additional information about MFs reduces the conservativeness of the suggested stability condition. Finally, examples are given to demonstrate the effectiveness of the proposed method.

Fixed-time control and estimation of discontinuous fuzzy leakage-delayed networks: Indefinite and economical conditions of Filippov systems

This paper considers the fixed-time stability of Filippov systems and discontinuous networks described by the Filippov systems. Firstly, the more generalized and economical inequality condition on Lyapunov function is proposed, which can not only improve the previous negative definite conditions, but also the indefinite conditions. Based on the definition of the Lyapunov stability and finite-time convergence, new fixed-time stability lemmas are proposed and the settling-time is also estimated. In order to apply the new fixed-time stability lemmas to the neural networks, fixed-time stabilization of a class of fuzzy leakage-delayed neural networks with discontinuous activations is considered which is rarely studied since the delay is leakage and activations are discontinuous and they are not easy to deal with simultaneously. By means of the Filippov regularization and differential inclusions theory, new criteria on the stabilization of the considered networks are derived via the new modified non-chattering controller, which can improve the previous ones with parameter and symbolic function. Finally, example and numerical simulations further examine the correctness of the main results.

Stream-aware indexing for distributed inequality join processing

Inequality join is an operator to join data on inequality conditions and it is a fundamental building block for applications. While methods and optimizations exist for efficient inequality join in batch processing, little attention has been given to its streaming version, particularly to large-scale data-intensive applications that run on Distributed Stream Processing Systems (DSPSs). Designing an inequality join in streaming and distributed settings is not an easy task: (i) indexes have to be employed to efficiently support inequality-based comparisons, but the continuous stream of data imposes continuous insertions, updates, and deletions of elements in the indexes—hence a huge overhead for the DSPSs; (ii) oftentimes real data is skewed, which makes indexing even more challenging.To address these challenges, we propose the Stream-Aware inequality join (STA), an indexing method that can reduce redundancy and index update overhead. STA builds a separate in-memory index structure for hotkeys, i.e., the most frequently used keys, which are automatically identified with an efficient data sketch. On the other hand, the cold keys are treated using a linked set of index structures. In this way, STA avoids many superfluous index updates for frequent items. Finally, we implement four state-of-the-art inequality join solutions for a widely employed DSPS (Apache Storm) and compare their performance with STA on four real-world data sets and a synthetic one. The results of our experimental evaluation reveal that our stream-aware approach outperforms existing solutions.

Equality Conditions for the Fractional Superadditive Volume Inequalities

Equality Conditions for the Fractional Superadditive Volume Inequalities

Expressions of inequalities in access to health services in Latin America: a scoping review.

Latin America is one of the most unequal regions in the world. Due to colonization and occupation of the territory, structural inequalities mark people's living and health conditions. In health, we can observe how different dimensions of inequalities condition access and user experience in the service. This scoping review aimed to map and analyze the expressions of inequalities in access to health services in Latin American countries from the scientific production of the last ten years, from which 272 articles were selected. The categorical analysis classified articles into five dimensions, which characterize the expressions of inequalities in access to health services: socioeconomic, geospatial, ethnic/racial, gender, and people with disabilities. The most frequent access barriers were socioeconomic or ability to pay, geographic or transportation difficulty, availability of services, cultural/ethnic, communication, and architecture. The main conditioning factors of health inequalities were income, schooling, transportation, and living conditions. Combating health inequalities requires proposing structuring and sectorial policies.

Positive Radial Symmetric Solutions of Nonlinear Biharmonic Equations in an Annulus

This paper discusses the existence of positive radial symmetric solutions of the nonlinear biharmonic equation ▵2u=f(u,▵u) on an annular domain Ω in RN with the Navier boundary conditions u|∂Ω=0 and ▵u|∂Ω=0, where f:R+×R−→R+ is a continuous function. We present some some inequality conditions of f to obtain the existence results of positive radial symmetric solutions. These inequality conditions allow f(ξ,η) to have superlinear or sublinear growth on ξ,η as |(ξ,η)|→0 and ∞. Our discussion is mainly based on the fixed-point index theory in cones.

Enhancing network security in constrained switched systems: event-triggered MPC with a buffer-based anti-attack approach

This paper explores event-triggered model predictive control (MPC) for constrained switched systems, incorporating a buffer-based anti-attack (BBAA) approach to ensure network security. Since the system state is unknown and disturbed, an observer-based H ∞ MPC approach is used to estimate the system state and suppress disturbance. Furthermore, the estimated state and control input can be optimised by minimising the performance function. Considering that the system state is subject to denial of service (DoS) attacks in the feedback channel, the BBAA approach is used to reconstruct the estimated state, thereby reducing the impact of attacks on system performance. To improve the utilisation of network resources, a set of event-triggering mechanisms (ETMs) is used. In addition, a set of matrix inequality conditions is given to constrain the gains of controllers and observers. Then, the system H ∞ performance is demonstrated by applying the average dwell time (ADT) and the Lyapunov function method, and the complex coupling between model switching, DoS attacks and event-triggering is analysed. Simulation results validate the effectiveness of the proposed approach.

Optimizing Economic Dispatch with Renewable Energy and Natural Gas Using Fractional-Order Fish Migration Algorithm

This work presents a model for solving the Economic-Environmental Dispatch (EED) challenge, which addresses the integration of thermal, renewable energy schemes, and natural gas (NG) units, that consider both toxin emission and fuel costs as its primary objectives. Three cases are examined using the IEEE 30-bus system, where thermal units (TUs) are replaced with NGs to minimize toxin emissions and fuel costs. The system constraints include equality and inequality conditions. A detailed modeling of NGs is performed, which also incorporates the pressure pipelines and the flow velocity of gas as procedure limitations. To obtain Pareto optimal solutions for fuel costs and emissions, three optimization algorithms, namely Fractional-Order Fish Migration Optimization (FOFMO), Coati Optimization Algorithm (COA), and Non-Dominated Sorting Genetic Algorithm (NSGA-II) are employed. Three cases are investigated to validate the effectiveness of the proposed model when applied to the IEEE 30-bus system with the integration of renewable energy sources (RESs) and natural gas units. The results from Case III, where NGs are installed in place of two thermal units (TUs), demonstrate that the economic dispatching approach presented in this study significantly reduces emission levels to 0.4232 t/h and achieves a lower fuel cost of 796.478 USD/MWh. Furthermore, the findings indicate that FOFMO outperforms COA and NSGA-II in effectively addressing the EED problem.

Revealing the impact of individual income inequality on different types of charitable giving in China through social interactions

AbstractObjectiveThis study delves into the correlation between individual income inequality as measured by the relative deprivation index and charitable giving, while also examining urban–rural heterogeneity. Additionally, it further explores the mechanisms by which online and offline forms of social interaction operate in this context.MethodsUtilizing data from the 2014–2020 China Family Panel Studies, we employed several methodologies including Probit regression models, cross‐model average marginal effects difference testing based on bootstrap method, instrumental variable method, and the Karlson–Holm–Breen (KHB) effect decomposition method.ResultsThe findings reveal that individual income inequality measured by the relative deprivation index significantly reduces charitable giving among Chinese households. The inhibitory effect of individual income inequality on social charitable giving is higher than that on charitable giving directed toward friends or colleagues. Furthermore, this impact exhibits some heterogeneity between urban and rural areas. Mechanism analysis indicates that the adverse effect of income inequality on charitable giving operates through reducing social interaction, including both online and offline forms.ConclusionOur results demonstrate that income inequality has distinct adverse effects on two types of charitable giving and explain the mechanisms underlying these effects through social interaction. A pattern of the differential mode of association similar to “ripples” in Chinese society is beneficial for understanding these differentiated impacts. We believe it is necessary to improve economic inequality conditions and enhance the enthusiasm of the Chinese public for participating in charitable donations by promoting various forms of social interaction.

The Existence and Uniqueness of Radial Solutions for Biharmonic Elliptic Equations in an Annulus

This paper concerns with the existence of radial solutions of the biharmonic elliptic equation ▵2u=f(|x|,u,|∇u|,▵u) in an annular domain Ω={x∈RN:r1<|x|<r2}(N≥2) with the boundary conditions u|∂Ω=0 and ▵u|∂Ω=0, where f:[r1,r2]×R×R+×R→R is continuous. Under certain inequality conditions on f involving the principal eigenvalue λ1 of the Laplace operator −▵ with boundary condition u|∂Ω=0, an existence result and a uniqueness result are obtained. The inequality conditions allow for f(r,ξ,ζ,η) to be a superlinear growth on ξ,ζ,η as |(ξ,ζ,η)|→∞. Our discussion is based on the Leray–Schauder fixed point theorem, spectral theory of linear operators and technique of prior estimates.

‘The barrier has to be jumped out with this music’: Collaborative creation in an after-school community music programme

Contemporary research into community music programmes highlights diverse contexts for collaborative music making. This article contributes a case of the collaboration in music making to a growing literature on creative practice in community music initiatives led by major orchestras. The authors reflect on field research involving an after-school programme that provides free, classical instrumental music instruction to primary school-age students who would not normally have an opportunity due to their socio-economic circumstances. The Pizzicato Effect, run by the Melbourne Symphony Orchestra (MSO) in the City of Hume, Australia has operated in the northern suburbs of Melbourne since 2009. Through focus group interviews with students, family members and teaching artists, the researchers examined community experiences of accruing cultural capital in conditions of social inequality and multicultural practice. Using qualitative methods, the case study aimed to position respondents as experts in their own lives, who own their knowledge of their worlds. Collaboration was central to a model of improvisation developed locally by teaching artists and applied on site. Furthermore, improvisation took the programme in different directions to the El Sistema model of youth orchestra training in Venezuela, which had been the original source of inspiration for the programme.

Data-driven event-triggering mechanism for linear systems subject to input saturation

This paper focuses on designing an event-triggering mechanism aimed at reducing control updates while maintaining the stability of a saturated closed-loop system. It addresses the regional stabilization of linear systems under input saturation conditions from a data-driven perspective. To do so, we propose a systematic method to convert model-driven conditions into data-driven control design Linear Matrix Inequality (LMI) conditions, enabling the co-design of the event-triggering rule and the state feedback gain. The theoretical contribution is then applied to the control of a spacecraft rendezvous problem.

Optimal event‐triggered control for wireless power transfer system in electric vehicles

AbstractThis study focuses on stabilizing a bidirectional inductive wireless power transfer (WPT) system using an event‐triggered approach. It is only assumed the inductor currents on both the primary and pickup sides are measurable, and they are sent synchronously to the controller via a digital channel. To estimate the unmeasured states and maintain plant stability, a full‐order state observer and an observer‐based controller have been developed. The control parameters are optimized through a genetic algorithm to achieve the desired output response. An emulation methodology is then applied to create an output‐based event‐triggering condition. This condition ensures the stability of the closed‐loop system even in the presence of communication constraints. To prevent Zeno sampling, a minimal time interval between two transmissions is enforced using time‐regularization techniques. Furthermore, the performance of the event‐triggered controller is enhanced by solving a linear matrix inequality condition, which further reduces the number of transmission instances. The methodology offers a systematic and optimal design for the bidirectional inductive WPT system. It eliminates the need for manual tuning of control parameters, which is particularly beneficial given the system's complex nature. To address both continuous‐time and discrete‐time dynamics, the entire system is represented as a hybrid dynamical system, making it more intuitive for networked control systems. The efficiency of this approach is assessed through numerical simulations of a WPT system, demonstrating its effectiveness. The results show that the average intertransmission interval has been increased from 0.0799 to 0.1782 s, that is, the proposed event‐triggering strategy reduced the number of transmissions to more than 50% compared with conventional periodic sampling.

The impact of government policies and regulations on the subjective well-being of farmers in two rural mountain areas of Italy

AbstractThe sustainable development of rural areas involves guaranteeing the quality of life and well-being of people who live in those areas. Existing studies on farmer health and well-being have revealed high levels of stress and low well-being, with government regulations emerging as a key stressor. This ethnographic study takes smallholder farmers in two rural mountain areas of Italy, one in the central Alps and one in the northwest Apennines, as its focus. It asks how and why the current policy and regulatory context of agriculture affects farmer well-being. Interviews and participant observation were conducted with 104 farmers. Three common scenarios emerged that negatively affect farmer well-being. First, policies and regulations designed for lowland areas do not always make sense when applied in the mountains. Second, when subsidies are put into effect at the local level, the reality of their implementation can veer away from the original goals of the funding program and have unintended effects on farmer well-being, agricultural practices, and the environment. Finally, when regulations are implemented on farms in rural mountain areas, the primacy of a techno-scientific knowledge system over other, local and place-based knowledge systems is exposed. These three scenarios affect well-being by eliciting feelings of stress, frustration, and disillusionment; by reducing farmer control over their work; and by fostering the perception that farming is not valued by society. They also create conditions of inequality and insecurity. The ways in which government policies and regulations play out on mountain farms can erode trust in government institutions, lead to an us versus them mentality, and contribute to the further abandonment of agriculture and rural areas.

Exponential stabilization of hybrid event‐triggered singular time‐delay systems

The exponential stability of hybrid event‐triggered singular time‐delay (STD) systems is established in this paper. To ensure their exponential stability, we give sufficient conditions for linear matrix inequalities (LMIs) for STD systems with average impulsive gain. Furthermore, zeno behavior is avoided by carefully designing the settings for event‐triggering conditions. A few numerical examples demonstrate the usefulness of the suggested findings.

Decentralized Fuzzy Fault Estimation Observer Design for Discrete-Time Nonlinear Interconnected Systems

In this paper, a fault estimation technique is proposed for discrete-time nonlinear interconnected systems with uncertain interconnections. To achieve the fault estimation, the decentralized fuzzy observer is adopted based on the Takagi–Sugeno fuzzy model. Based on the estimation error model with the subsystems of the interconnected system and its decentralized fuzzy observer, the fault estimation condition with H∞ performance is presented. The main idea of this paper is that a novel inequality condition for H∞ performance is used, and the sufficient condition is presented to guarantee the good fault estimation performance. Also, the decentralized fuzzy observer design condition for the fault estimation is converted into linear matrix inequality formats. Finally, a simulation example is provided, and the effectiveness of the proposed fault estimation technique is verified by comparison of the fault estimation performance.

Mapping the Discourse of Gender Subordination in the Art World in Indonesia

Instead of hastily trying to throw out a discourse that rarely or has never appeared in related discussions, what then becomes the breath of the analysis in this scientific article is an effort to mapping the position of women's gender subordination and the representation of women artists discourses in the dialogue of a special scope, namely Indonesian art world. The analysis was carried out using three theoretical concepts, namely subordination, symbolic violence and representation in the art world in Indonesia. By conducting a literature study on literature and art events, the results of this scientific research show that: (1) Collective awareness is believed to support the articulation of resistance to gender inequality; (2) This awareness extends to the involvement of male artists as well, but there are other articulation practices that are more reflective in nature, meaning the construction of the gender identity of the female artist; and (3) The condition of gender inequality is also voiced in-depth reflections aimed at erasing the gender dichotomy caused by stereotypes.