General System Research Articles

Under-five mortality during the war in Tigray: A community-based study.

Child mortality is one of the key indicators of the Sustainable development goals. The Ethiopian healthcare system in general and Tigray's healthcare system in particular has shown a remarkable progress in terms of reducing maternal, neonatal, and under-five mortality in the last couple of decades. However, the war erupted in November 2020 caused the healthcare system to collapse and little is known about the status of child mortality in Tigray. Thus, this study aimed to examine the magnitude and causes of under-five child mortality in the embattled Tigray region was conducted from October 2020 - May 2022. A cross-sectional community-based survey was employed. The study included all zones except the western zone and some areas of eastern and north western Tigray bordering Eritrea. These areas were skipped for security reasons. Based on multistage cluster sampling, 121 tabiyas in districts were selected. Census was conducted to survey 189,087 households in the 121 Tabiyas. A locally developed household screening tool and the latest world health organization verbal autopsy instrument were used. The Verbal Autopsy data was processed using the Inter-VA-5.1 (probabilistic modeling) to assign the cause of death. Under-five mortality rate (U5MR) was calculated per 1000 live births with a 95% confidence interval (CI). In the present study, out of 29,761 live births, 1761 under-five children died giving an under-five mortality rate of 59(95% CI, 57-62) per 1000 live births. Deaths in the neonatal period and post-neonatal period accounted for 60% and 19.9% of the deaths respectively. Overall, the top 3 causes of under-five child mortality in the present study were: Perinatal asphyxia (n = 277,18%,) prematurity (n = 235,16%) and diarrheal diseases (n = 162, 12.5%). In those who died after first month of life, diarrheal diseases, lower respiratory tract infection, sever acute malnutrition and HIV were the main causes of death. Concerning the place of death, 61.6% of the children died at home. The present study revealed the doubling of under-five mortality in Tigray from where the figure stood in the pre-war period. The leading causes of death in under-five mortality are potentially preventable in situation where the healthcare system is functioning. Restoring the healthcare system and its apparatus, improving access to skilled institutional delivery, smooth perinatal transition, improving nutrition status of children, access to full course of vaccines could ameliorate the staggering under-five mortality rate in the war in Tigray.

The relationship between space and time perception: A registered replication of Casasanto and Boroditsky (2008).

Everything in our environment moves through both space and time, and to effectively act we must be aware of both spatial and temporal elements in relation to our own bodies. Thus, perceptions of space and time have an intimate relationship. Walsh's a theory of magnitude (ATOM) suggests that space and time perception rely on a general magnitude system and their relationship should be roughly symmetrical. Alternatively, metaphor theory, which is based on the philosophical work of Lakoff and Johnson, argues that we represent time using a spatial metaphor and thus the relationship should be asymmetrical (with space influencing time more than time influences space). A compelling line of evidence for metaphor theory comes from the work of Casasanto & Boroditsky. Cognition, 106(2), 579-593. (2008) who experimentally demonstrated this asymmetric effect. However, in our previous unpublished online replication attempt of this work, we found a roughly symmetrical relationship between space and time, more in line with the theoretical predictions of ATOM. Given this, we performed a registered replication of Casasanto & Boroditsky. Cognition, 106(2), 579-593. (2008) in both an online and laboratory environment.

Event-triggered fixed-time distributed observers for general linear systems

This paper delves into the implementation of a distributed fixed-time state estimation approach for linear systems, utilizing an event-triggered strategy. Particularly, the output data from the linear systems are strategically distributed across various observers. A novel fixed-time distributed observer is proposed to reconstruct full states of the linear system cooperatively with the observer error converges to zero within fixed time. Based on the event-triggered strategy, the communication times among observers are reduced by intermittent communication. Simultaneously, Zeno-behavior is ruled out completely. Finally, the proposed results are verified by a simulation example.

Risk assessment of general FPSO supply system based on hybrid fuzzy fault tree and Bayesian network

One of the major risks to the operation of a FPSO (Floating, Production, Storage and Offloading) is collision of supply vessels. Experiences have shown that collisons of supply vessel take place frequently, although the consequences are limited. The offshore oil&gas industry has established relevant design standards and operational procedures, which are proven to be effective in reducing this risk. As the risk assessment becomes increasingly applied, there is a need to quantify the likelihood of supply vessel collisions especially duing the early design/project stage when historical incident data does not exist. This paper proposees a method for estimating the likelihood of supply vessel collision based on fault tree analysis (FTA), Bayesian network (BN), hybrid theory and fuzzy theory. In liew of using historicval data, this method combines the fuzzy logic with expert heuristics to determine the basic events(BEs). The triangular fuzzy membership functions and a hybrid theory were adopted to define factors that lack data or had no data in the events. To account for the imprecise information of human error, a scheme is devised to use the fuzzy fault probability(FFP) based on the hybrid theory, or a hybrid fuzzy fault tree analysis (HFFT). The algorithm transforms the FT into a BN with a conditional probability table (CPT). This new method was demonstrated in an example of a FPSO, and the results were has been validated through case studies and accident reports. A sensitivity analysis was also conducted to illustrate key parameters.

Observer-based time-varying formation-containment tracking of general linear multi-agent systems with input saturation

In this article, we study the time-varying formation-containment (TVFC) tracking problem for linear multi-agent systems (MASs) and take the input saturation problem of the systems into account. An observer-based TVFC tracking protocol is proposed. It has been proven that the real leaders can realize the expected formation and track the virtual leader’s trajectory, and followers can get into the convex envelope spanned by the leaders. In addition, to avoid unexpected large chattering caused by nonzero input, we propose a continuous protocol. Under this protocol, each error is uniformly ultimately bounded and is able to converge to any small zero neighborhood. At the end, the feasibility of the TVFC theory is demonstrated by simulation examples.

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.

Multi-Physics Modeling and the Sensitivity Analysis for the Critical Factors in Solid Oxide CO2-Steam Co-Electrolysis System Performances

A multi-physics modeling framework, which includes electrochemical and chemical reactions, mass transfer, and energy balance, has been developed and validated against experiment measurements to investigate the performance of solid oxide CO2-steam co-electrolysis (SOEC) under various operating conditions and cell designs. However, multi-physics modeling for complex SOEC systems can be computationally expensive and not tractable for general system design and optimization. Reduced-order models (ROMs) have been proven as a powerful tool for reducing computational costs, closely mimic the high-fidelity SOEC stack models and identify the operational condition parameters to which the SOEC stack is sensitive and needs appropriate controls for stable operation. In this study, the deep neural networks (DNN) algorithm is employed to construct ROMs according to multi-physics simulations for SOECs to systematically investigate the SOECs’ electrochemical performance and rank the contributions of operational condition parameters for both 2 cm2 button cell and 300 cm2 planar cells. Sensitivity analysis reveals that cell voltage, fuel composition (denoted by CO2/H2O ratio), and the operating temperature impact the cell performance most. The product ratio ΔCO/ΔH2 has a stronger dependence on the CO2/H2O ratio in the fuel compositions than on other operating condition parameters. The large 300 cm2 planar cells were modeled under both adiabatic and furnace environment. The simulation and sensitivity analysis indicate that the large cell operating in adiabatic environment usually provides relatively lower performances than the one in furnace environment. Additionally, the adiabatic environment also causes the cell’s performances are more sensitive to the operation conditions, such as external voltage, fuel flow rate, and fuel compositions. The large cell in adiabatic environment also leads to higher internal temperature variation, which may impact the structure reliability.

Efficiency Measurements of Energy Harvesting from Electromagnetic Environment for Selected General Purpose Telecommunication Systems

The results of measurements of the efficiency of energy harvesting from commonly available general-purpose telecommunications systems, divided into typical bands available under European conditions, have been presented in this paper. Specially designed harvesters were used, dedicated to powering autonomous semi-passive Radio Frequency Identification (RFID) tags. For the assumed resistive loads, the achievable output voltage values of the harvesters were measured across a wide spectrum of electromagnetic field strengths, simulating real conditions. The performance and dynamics of the energy storage process with fixed parameters were studied at an intermediate stage, before the energy conditioning process. The harvesters were treated as typical energy sources with unknown but variable parameters, so their dynamic parameters and instantaneous energy supply were also analyzed. These activities will enable the final development of a power supply system with parameters acceptable for the planned applications and whose efficiency will be maximized under the given conditions. For this purpose, the energy harvesting systems were designed, a suitable laboratory stand was built, and the elaborated circuits were measured to determine the expected parameters of energy harvesting.

PREJUDICE AS A MEANS OF PROOF IN CRIMINAL PROCEEDINGS IN UKRAINE: A COMPARATIVE ANALYSIS WITH CONTINENTAL AND COMMON LAW SYSTEMS

Background: During the preparation of the CPC of Ukraine in 2012, the issue of legal regulation regarding the use of prejudice in the process of criminal procedure proof received little scholarly attention. Although much time has passed since then, this subject of discussion remains largely unexplored in textbooks and manuals on criminal procedure published after the adoption of the codified act. Even within the few scholarly investigations dedicated to prejudice in criminal proceedings, a communis opinion doctorum on some issues related to the means of proof has yet to be achieved. This article aims to clarify the concept, formulate its characteristics, uncover the significance of prejudice in Ukraine’s criminal procedure, and distinguish peculiarities of legal regulation and the use of this means of proof in criminal procedure law of countries with continental and general systems of law. Methods: The methodological basis of the article is a dialectical approach to the scientific understanding of social phenomena. In writing this article, general scientific and specialised legal methods of cognition were also used, including analysis, generalisation, structural and functional methods, hermeneutic methods, doctrinal or specialised legal methods, and comparative legal methods. Results and conclusions: It has been found that prejudicial significance is attributed to legal acts that summarise the outcome of criminal procedural activities in specific criminal proceedings. These legal acts include final judgments and rulings of the court and unrevoked decisions of the interrogator, investigator, detective, and prosecutor. Prejudice encompasses not only relevant facts and circumstances but also legal conclusions regarding them. The principleof free evaluation of proof allows the parties to come to different legal conclusions than those made in the previous criminal proceedings, with proper argumentation of their legal position. The use of prejudice in criminal proceedings of civil law jurisdictions is based on the doctrine of res judicata, while in common law systems, it is based on the doctrine of collateral estoppel. Examples from the criminal procedure of Poland, Greece, Italy, and the USA illustrate the specific features of using this means of proof.

When is lethal deceptive pollination maintained? A population dynamics approach.

Not all plant-pollinator interactions are mutualistic, and in fact, deceptive pollination systems are widespread in nature. The genus Arisaema has a pollination system known as lethal deceptive pollination, in which plants not only attract pollinating insects without providing any rewards, but also trap them until they die. Many Arisaema species are endangered from various disturbances including reduction in forest habitat, modification of the forest understory owing to increasing deer abundance, and plant theft for horticultural cultivation. We aimed to theoretically investigate how lethal deceptive pollination can be maintained from a demographic perspective and how plant and pollinator populations respond to different types of disturbance. We developed and analysed a mathematical model to describe the population dynamics of a deceptive plant species and its victim pollinator. Calibrating the model based on empirical data, we assessed the conditions under which plants and pollinators could coexist, while manipulating relevant key parameters. The model exhibited qualitatively distinct behaviours depending on certain parameters. The plant becomes extinct when it has a low capability for vegetative reproduction and slow transition from male to female, and plant-insect co-extinction occurs especially when the plant is highly attractive to male insects. Increasing deer abundance has both positive and negative effects because of removal of other competitive plants and diminishing pollinators, respectively. Theft for horticultural cultivation can readily threaten plants whether male or female plants are frequently collected. The impact of forest habitat reduction may be limited compared to that of other disturbance types. Our results have emphasised that the demographic vulnerability of lethal deceptive pollination systems would differ qualitatively from that of general mutualistic pollination systems. It is therefore important to consider the demographics of both victim pollinators and deceptive plants to estimate how endangered Arisaema populations respond to various disturbances.

Mean dimension of induced hyperspace dynamical systems

In this paper, we prove that the mean dimension of the hyperspace dynamical system induced by a dynamical system with positive mean dimension is infinite. Specifically, for the full shift (KZ,σ) over a finite-dimensional compact metric space K, we find that mdim(2KZ,2σ)=+∞ if and only if mdim(KZ,σ)>0. However, for general dynamical systems, we cannot assume that this result holds universally. In this paper, we present a counterexample where the mean dimension of the dynamical system is 0 while the mean dimension of the induced hyperspace dynamical system is infinite.

Distributed Dynamic Event-Triggered Consensus Protocol for General Linear Multiagent Systems Without Accurate System Information.

This study focuses on distributed event-triggered consensus control under the scenario where only inaccurate agent model information is available. By designing a novel triggering error, a distributed dynamic event-triggered consensus (DETC) protocol is proposed for multiagent systems (MASs) with general linear dynamics over digraphs, without accurate a priori information of agent models. To improve the efficiency of the dynamic triggering law, a mixed triggering threshold is designed with a resilient function integrated to further enlarge interevent intervals. Within the proposed DETC protocol, the computational cost is significantly reduced especially for MASs with nonsparse and high-dimensional agent system matrices. In addition, for each individual agent, the states of neighboring agents used for triggering detections or controller updates are required in an on-demand (instead of continuous) way, which preserves communication resources and facilitates practical implementation. The feasibility of the designed DETC protocol is corroborated by rigorous theoretical analysis on consensus convergence and Zeno behavior exclusion. Finally, simulations are shown to demonstrate the effectiveness of the studied theory.

Reinforcement Learning Control of Hypersonic Vehicles and Performance Evaluations

This work presents a new framework for model-based continuous-time reinforcement learning (CT-RL) control of hypersonic vehicles (HSVs). The predominant classes of CT-RL methods for general nonlinear systems in adaptive dynamic programming (ADP) and deep RL tend to either present substantial theoretical results but lack practical synthesis capability (ADP) or show empirical promise without offering theoretical guarantees (deep RL). Meanwhile, RL control frameworks developed directly for HSVs tend to require a simplified model and complicated control structure, and they lack the substantial numerical evaluations essential for real-world flight implementation. To directly address these challenges, we propose a new decentralized excitable integral reinforcement learning framework within which the reference input-based exploration improves persistence of excitation. Together with new insights on prescaling and established decentralized control structure for HSVs, we demonstrate the resulting controller for significant performance improvement over classical Linear Quadratic Regulator (LQR) and feedback linearization methods. Additionally, we provide convergence, optimality, and closed-loop stability guarantees of the proposed method. We demonstrate these performance guarantees over a set of substantial and systematic numerical evaluations on an unstable, nonminimum phase HSV model subject to varying modeling errors and initial conditions.

Fixed-Time Consensus Control of General Linear Multiagent Systems

Fixed-Time Consensus Control of General Linear Multiagent Systems

Robust adaptive learning control using spiking-based self-organizing emotional neural network for a class of nonlinear systems with uncertainties

For second-order general nonlinear systems with uncertainties, a control scheme combining fractional-order fast terminal sliding mode control (FOFTSMC) and self-organizing emotional neural network (SOENN) is proposed and designed. Firstly, a novel emotional neural network which can approximate the uncertainties in nonlinear systems is constructed and introduced. Meanwhile, in order to optimize the network structure and reduce the computing burden, a novel spiking-based self-organizing mechanism is added. Then the FOFTSMC is designed for second-order general nonlinear systems, and the stability and finite time convergence is proved by Lyapunov theory. Besides, the FOFTSMC and SOENN are combined to form the final control scheme, and adaptive laws of the parameters are also designed. Finally, inverted pendulum and active power filter (APF) are selected as the research objects to carry out a series of simulations and experiments to validate and highlight the effectiveness and superiority of the proposed control scheme.

Right-wing authoritarianism, social dominance, system justification, and conservative political ideology as predictors of mental health stigma: The Hungarian case.

Insights from mental health stigma research indicate the importance of societal and political views on mental health perceptions. Most studies originate from typical Western neo-liberal settings and focus on generic mental health issues. Our research explores these associations in Hungary, an understudied post-communist context with significant stigma levels, examining a broad range of stigmas related to both general and three specific mental illnesses: schizophrenia, depression, and alcohol use disorder (AUD). The study aims to connect a wide array of political dispositions to stigma associated with both general and specific mental illnesses, exploring both attitudes and behavioral intentions. We surveyed 492 participants (147 males, 342 females) on their political dispositions, including Right-Wing Authoritarianism (RWA), Social Dominance Orientation (SDO), general and economic system justification, and conservative political ideology, and their attitudes toward general and specific mental illnesses. Regression analyses identified key political dispositions influencing stigma. RWA was significantly linked to most stigma outcomes, while conservative political ideology showed a selective impact. Other predictors had minimal influence on stigma outcomes. Our findings suggest that perceptions of danger, threat, and unconventionality, as indicated by RWA, are crucial for mental health stigmatization in Hungary. Intervention programs should target these factors, particularly in similar contexts.

Extended explicit Pseudo two-step Runge-Kutta-Nyström methods for general second-order oscillatory systems

Extended explicit Pseudo two-step Runge-Kutta-Nyström methods for general second-order oscillatory systems

More considerations about the symmetry of the stress tensor of fluids.

Regarding a recent dispute about the symmetry of the stress tensor of fluids, more considerations are presented. The usual proofs of this symmetry are reviewed, and contradictions between this symmetry and the mechanism of gas viscosity are analyzed for simple gas flows. It is emphasized that these proofs depend on the theorem of angular momentum that assumes that internal forces between any two fluid particles are always along the line connecting them. Without this assumption, from Newton's laws of motion one can only obtain the theorem of angular momentum with an additional term. It is proved within classical continuum mechanics that this additional term represents the total moment of internal forces, and its volume density is similar to the body couple introduced in generalized continuum mechanics. When discrete structure of matter is considered, this term corresponds to the total moment of the forces exerted on the nuclei by the internal electrons. This moment of internal forces may lead to nonsymmetry of the stress tensor and is, in general, nonzero as long as shear stress exists. A nonsymmetrical stress tensor suggested in the literature is discussed in terms of its effects in eliminating the contradictions and simplifying the Navier-Stokes equation. The derivation of this stress tensor for ideal gases based on the kinetic theory of gas molecules is presented, and its form in a general orthogonal curvilinear coordinate system is given. Finally, a possible experimental verification of this nonsymmetrical stress tensor is discussed.

A General Copper-Box System for the Asymmetric Arylative Functionalization of Benzylic, Propargylic or Allenylic Radicals.

Radical-involved arylative cross-coupling reactions have recently emerged as an attractive strategy to access valuable aryl-substituted motifs. However, there still exist several challenges such as limited scope of radical precursors/acceptors, and lack of general asymmetric catalytic systems, especially regarding the multicomponent variants. Herein, we reported a general copper-Box system for asymmetric three-component arylative radical cross-coupling of vinylarenes and 1,3-enynes, with oxime carbonates and aryl boronic acids. The reactions proceed under practical conditions in the absence or presence of visible-light irradiation, affording chiral 1,1-diarylalkanes, benzylic alkynes and allenes with good enantioselectivities. Mechanistic studies imply that the copper/Box complexes play a dual role in both radical generation and ensuing asymmetric cross-coupling. In the cases of 1,3-enynes, visible-light irradiation could improve the activity of copper/Box complex toward the initial radical generation, enabling better efficiency match between radical formation and cross-coupling.

Particle scattering and fusion for the Ablowitz–Ladik chain

The Ablowitz–Ladik (AL) chain is an integrable discretized version of the nonlinear Schrödinger equation. We report on a novel underlying Hamiltonian particle system with properties similar to the ones known for the classical Toda chain and Calogero fluid with 1/sinh2 pair interaction. Boundary conditions are imposed such that, both in the distant past and future, particles have a constant velocity. We establish the many-particle scattering for the AL chain and obtain properties known for generic integrable many-body systems. For a specific choice of the chain, real initial data remain real in the course of time. Then, asymptotically, particles move in pairs with a velocity-dependent size and scattering shifts are governed by the fusion rule.