Control Mechanisms Research Articles

Mechanism of active flow control using a novel spike aerodome-channel concept in the hypersonic flow: A numerical study

Among the design requirements of hypersonic vehicles, reducing aerodynamic heating and drag force simultaneously is the main challenge. This paper proposes a novel spike aerodome-channel combination concept to realize the flow field reconstruction around the hypersonic blunt body. The novel configuration is investigated in the axisymmetric flow at a Mach number of 6 at zero angle of attack. The two-dimensional Reynold-averaged Navier–Stokes equations are numerically solved, and the shear-stress transport k–ω model is the turbulence model implemented in this study. Parameters such as spike length and lateral jet location are investigated to explore the drag and heat reduction performance and the flow control features. The obtained results show that the application of the novel spike aerodome-channel concept alters the flow field by eliminating or replacing the strong bow shock wave, and the design of hypersonic vehicles can benefit from the application of the proposed concept. The blunt body coupled with a frustum of cone-tipped spike-channel configuration provides a remarkable drag reduction effect of 20.71% with respect to the case without channel. Considering the effect of lateral jet location, the drag reduction performance of the case with LR = 0.75 is superior to that of the root jet case at the same spike length, and a considerable drag reduction of 28.93% is obtained with L/D = 2.4. In addition, longer spike length is beneficial for improving drag reduction performance, while excellent efficiency of heat protection is obtained in a certain spike length range. For the case of L/D = 1.6 with root jet, the peak Stanton number is significantly decreased by 33.51%.

Septins promote macrophage pyroptosis by regulating gasdermin D cleavage and ninjurin-1-mediated plasma membrane rupture.

The septin cytoskeleton is primarily known for roles in cell division and host defense against bacterial infection. Despite recent insights, the full breadth of roles for septins in host defense is poorly understood. In macrophages, Shigella induces pyroptosis, a pro-inflammatory form of cell death dependent upon gasdermin D (GSDMD) pores at the plasma membrane and cell surface protein ninjurin-1 (NINJ1) for membrane rupture. Here, we discover that septins promote macrophage pyroptosis induced by lipopolysaccharide (LPS)/nigericin and Shigella infection, but do not affect cytokine expression or release. We observe that septin filaments assemble at the plasma membrane, and cleavage of GSDMD is impaired in septin-depleted cells. We found that septins regulate mitochondrial dynamics and the expression of NINJ1. Using a Shigella-zebrafish infection model, we show that septin-mediated pyroptosis is an invivo mechanism of infection control. The discovery of septins as a mediator of pyroptosis may inspire innovative anti-bacterial and anti-inflammatory treatments.

Macroscale brain states support the control of semantic cognition

A crucial aim in neuroscience is to understand how the human brain adapts to varying cognitive demands. This study investigates network reconfiguration during controlled semantic retrieval in differing contexts. We analyze brain responses to two semantic tasks of varying difficulty – global association and feature matching judgments – which are contrasted with non-semantic tasks on the cortical surface and within a whole-brain state space. Demanding semantic association tasks elicit activation in anterior prefrontal and temporal regions, while challenging semantic feature matching and non-semantic tasks predominantly activate posterior regions. Task difficulty also modulates activation along different dimensions of functional organization, suggesting different mechanisms of cognitive control. More demanding semantic association judgments engage cognitive control and default mode networks together, while feature matching and non-semantic tasks are skewed towards cognitive control networks. These findings highlight the brain’s dynamic ability to tailor its networks to support diverse neurocognitive states, enriching our understanding of controlled cognition.

Generalization of sequence effects from conflict to cueing tasks.

Cognitive control has been investigated in attentional conflict tasks for a long time. One representative phenomenon of adaptive cognitive control in these tasks is the congruency sequence effect (CSE), which means that a previous conflict will lead to reduced congruency effects at the current moment, reflecting increased control of attention toward the task at hand. One debating question is whether CSE can generalize between different conditions. Since a similar phenomenon (i.e., validity sequence effect, VSE) has been found in spatial cueing tasks, this study investigated whether the two sequential effects could generalize between each other. A cross-task sequence effect is found from previous flanker trials to current cueing trials when the task sets of the two tasks are either very similar or sufficiently dissimilar, and this C-VSE effect is influenced by the response mode of the experimental design. In addition, the VSE between trial n-2 and trial n is eliminated by the existence of an intermediate flanker trial, but the CSE between trial n-2 and trial n is still significant even with an intermediate cueing trial. Possible explanations of these findings are discussed. The findings suggest a close connection between orienting and executive control processes in attention networks and provide a new perspective and method for investigating the potential mechanisms of cognitive control.

Ethical Considerations and Fundamental Principles of Large Language Models in Medical Education: Viewpoint.

This viewpoint article first explores the ethical challenges associated with the future application of large language models (LLMs) in the context of medical education. These challenges include not only ethical concerns related to the development of LLMs, such as artificial intelligence (AI) hallucinations, information bias, privacy and data risks, and deficiencies in terms of transparency and interpretability but also issues concerning the application of LLMs, including deficiencies in emotional intelligence, educational inequities, problems with academic integrity, and questions of responsibility and copyright ownership. This paper then analyzes existing AI-related legal and ethical frameworks and highlights their limitations with regard to the application of LLMs in the context of medical education. To ensure that LLMs are integrated in a responsible and safe manner, the authors recommend the development of a unified ethical framework that is specifically tailored for LLMs in this field. This framework should be based on 8 fundamental principles: quality control and supervision mechanisms; privacy and data protection; transparency and interpretability; fairness and equal treatment; academic integrity and moral norms; accountability and traceability; protection and respect for intellectual property; and the promotion of educational research and innovation. The authors further discuss specific measures that can be taken to implement these principles, thereby laying a solid foundation for the development of a comprehensive and actionable ethical framework. Such a unified ethical framework based on these 8 fundamental principles can provide clear guidance and support for the application of LLMs in the context of medical education. This approach can help establish a balance between technological advancement and ethical safeguards, thereby ensuring that medical education can progress without compromising the principles of fairness, justice, or patient safety and establishing a more equitable, safer, and more efficient environment for medical education.

State Estimation of Switched Time-Delay Complex Networks With Strict Decreasing LKF.

State estimation issue is investigated for a switched complex network (CN) with time delay and external disturbances. The considered model is general with a one-sided Lipschitz (OSL) nonlinear term, which is less conservative than Lipschitz one and has wide applications. Adaptive mode-dependent nonidentical event-triggered control (ETC) mechanisms for only partial nodes are proposed for state estimators, which are not only more practical and flexible but also reduce the conservatism of the results. By using dwell-time (DT) segmentation and convex combination methods, a novel discretized Lyapunov-Krasovskii functional (LKF) is developed such that the value of LKF at switching instants is strict monotone decreasing, which makes it easy for nonweighted L2 -gain analysis without additional conservative transformation. The main results are given in the form of linear matrix inequalities (LMIs), by which the control gains of the state estimator are designed. A numerical example is given to illustrate the advantages of the novel analytical method.

Internet of things-based rice field irrigation evaporation monitoring system

The urgency for efficient irrigation in Indonesia’s agriculture sector, particularly in paddy fields, is evident. However, existing methods for monitoring water levels are antiquated, often requiring manual measurements with a ruler. This research introduces a comprehensive “monitoring system for light intensity and water temperature as an analysis of evaporation for rice irrigation based on the internet of things”. The system integrates various sensors an anemometer for wind speed, an ultrasonic sensor for water level, a DS18B20 waterproof sensor for water temperature, and a GY-8511 sensor for sunlight intensity. All data are collected by an Arduino Mega controller, connected to an ESP32 for transmitting the readings to the Blynk app and an I2C 20×4 liquid crystal display (LCD) screen. The control mechanism employs a closed-loop system with a direct current (DC) motor actuator to operate the water gate, which can also be manually controlled via a cellphone. The system effectively meets daily evapotranspiration requirements of 1.44 mm, with optimal conditions yielding water levels of 3 cm, water temperatures of 38.53 °C, sunlight intensity of 4.59 mW/cm², and wind speed of 0.21 m/s.

The flow control mechanism of trailing-edge Gurney flap on a 50°-swept delta wing in forced pitching

The flow control effect of the trailing-edge Gurney flap (TG) on the dynamic lift characteristics for a 50°-swept delta wing during large-amplitude pitching oscillations at various reduced frequencies (k = 0.072, 0.144, 0.287, and 0.575) was investigated via force, particle image velocity, and dye visualization measurements in a water channel facility. Numerical simulations were carried out to further understand the flow control mechanism of the TG in low and high reduced frequency cases (k = 0.072 and 0.575). It was found that as the reduced frequency increases, the lift increments brought by the TG are magnified and abated during the upstroke and downstroke processes, respectively. The breakdown of the leading-edge vortex (LEV) on the upper surface of the wing is promoted by the TG during the early stage of the pitching cycle. The lift enhancement being benefited by the TG is mainly contributed by the recovery of lower surface pressure along the trailing edge due to the blockage effect of TG, which also stimulates the spanwise flow and strengthens the LEV upon the upper surface. The significant lift increment contribution of the upper surface during the upstroke process can be maintained to higher angle of attack as the reduced frequency increases.

The interplay of cognitive control and feature integration: insights from theta oscillatory dynamics during conflict processing.

Adaptive behavior is fundamental to cognitive control and executive functioning. This study investigates how cognitive control mechanisms and episodic feature retrieval interact to influence adaptiveness, focusing particularly on theta (4 to 8Hz) oscillatory dynamics. We conducted two variations of the Simon task, incorporating response-incompatible, response-compatible, and neutral trials. Experiment 1 demonstrated that cognitive adjustments-specifically, cognitive shielding following incompatible trials and cognitive relaxation following compatible ones-are reflected in midfrontal theta power modulations associated with the Simon effect. Experiment 2 showed that reducing feature overlap between trials leads to less pronounced sequential modulations in behavior and midfrontal theta activity, supporting the hypothesis that cognitive control and feature integration share a common neural mechanism. These findings highlight the interaction of cognitive control processes and episodic feature integration in modulating behavior. The results advocate for hybrid models that combine top-down and bottom-up processes as a comprehensive framework to understand cognitive control dynamics and adaptive behavior.

Plant Control Mechanisms and Autonomous Control

Plant Control Mechanisms and Autonomous Control

The Mechanism of Control over the Activities of Executive Authorities in the Russian Federation

The Mechanism of Control over the Activities of Executive Authorities in the Russian Federation

EXPRESS: Untangling the Duality of Emerging Market Firms’ Response to OFDI Policies on Their Innovation Performance: A Resource Dependence Perspective

Firms’ international expansion, affected by outward foreign direct investment (OFDI) policies of home countries, can greatly shape their innovation performance. Yet, existing literature lacks sufficient investigation toward the nexus between corporate response to policies in OFDI activities and subsequent innovation performance. Thus, the authors designed this study to examine how a firm’s response to OFDI policies affects its innovation performance. Drawing upon the resource dependence theory, the authors theorize corporate response to OFDI policies as firm dependence on home government. By arguing that such dependence differentially affects firm innovation through support and control mechanisms, they elucidate the inverted U-shaped relationship between corporate response to OFDI policies (measured by the percentage of a firm’s OFDI projects in policy-favored markets) and innovation performance (measured as patent counts). Furthermore, this curvilinear relationship, they posit, is moderated and strengthened by home-government subsidies the firm receives (calculated as the ratio of annual subsidies received to yearly sales). With archival data of 2,050 Chinese listed manufacturing firms responding to specific OFDI policies during 2013–2021, their predictions are corroborated. Overall, by illuminating the innovation implications of OFDI as corporate response to policies, this study contributes to the international marketing literature in the context of emerging markets.

Advancing Offshore Renewable Energy: Integrative Approaches in Floating Offshore Wind Turbine-Oscillating Water Column Systems Using Artificial Intelligence-Driven Regressive Modeling and Proportional-Integral-Derivative Control

This research investigates the integration of Floating Offshore Wind Turbines (FOWTs) with Oscillating Water Columns (OWCs) to enhance sustainable energy generation, focusing on addressing dynamic complexities and uncertainties inherent in such systems. The novelty of this study lies in its dual approach, which integrates regressive modeling with an aero-hydro-elasto-servo-mooring coupled system with a deep data-driven network and implements a proportional-integral-derivative (PID) control mechanism to improve system stability. By employing Artificial Neural Networks (ANNs), the study circumvents the challenges of real-time closed-loop control on FOWT structures using the OpenFAST simulation tool. Data-driven models, trained on OpenFAST datasets, facilitate real-time predictive behavior analysis and decision-making. Advanced computational learning techniques, particularly ANNs, accurately replicate the dynamics of FOWT-OWC numerical models. An intelligent PID control mechanism is subsequently applied to mitigate structural vibrations, ensuring effective control. A comparative analysis with traditional barge-based FOWT systems underscores the enhanced modeling and control methodologies’ effectiveness. In this sense, the experimental results demonstrate substantial reductions in the mean oscillation amplitude, with reductions from 5% to 35% observed across various scenarios. Specifically, at a wave period from 20 s and a wind speed of 5 m/s, the fore-aft displacement was reduced by 35%, exemplifying the PID control system’s robustness and efficacy under diverse conditions. This study highlights the potential of ANN-driven modeling as an alternative to managing the complex non-linear dynamics of NREL 5 MW FOWT models and underscores the significant improvements in system stability through tailored PID gain scheduling across various operational scenarios.

Abstract task sequence initiation deficit dissociates anxiety disorders from obsessive-compulsive disorder and healthy controls.

In everyday life, humans perform sequences of tasks. These tasks may be disrupted in people with obsessive-compulsive disorder (OCD). Symptoms, such as compulsions, can be considered sequential and often cause repetitions of tasks that disrupt daily living (e.g., checking the stove while cooking). Motor sequences have been used to study behavioral deficits in OCD. However, not all sequences are motor sequences. Some are more "abstract" in that they are composed of a series of tasks (e.g., chopping and stirring) rather than being dependent on individual actions or stimuli. These abstract task sequences require cognitive control mechanisms for their execution. Although theory has proposed deficits in these sequences in OCD as well, they have not been directly investigated. We tested the hypotheses that OCD participants exhibit deficits in the control mechanisms specific to abstract task sequences and more general flexible behavior (measured with task switching within the sequences), relative to health controls (HCs) and clinical controls (participants with anxiety disorders [ANX]). A total of 112 participants completed abstract task sequences consisting of simple categorization tasks. Surprisingly, participants with OCD did not perform worse than HCs or ANX. However, ANX participants showed impairments specific to sequential control that did not extend to more general flexible control. Thus, we showed a novel behavioral dissociation between OCD and ANX specific to abstract task sequential control. These results also implicate deficits in specific frontal sequential control neural circuitry in ANX and not in OCD, where implicit sequential deficits may more closely align with striatal circuits.

Strengthening Global Security: Critique on the NPT and NSG Mechanisms of Nuclear Export Control Regime

An export control regime plays a vital tool in the effort to counter the proliferation of traditional weapons and weapons of mass destruction. However, there are new and fundamental challenges with this system. The article emphasizes the importance of understanding and implementing nuclear export control mechanisms to advance international security and prevent the spread of nuclear weapons. The research will apply descriptive analysis of the mechanisms of nuclear export controls. Critical analysis of the nuclear export control apparatuses will be applied as a technique to review the loopholes in the enforcement mechanisms of these initiatives. The debate covers key aspects of nuclear export control, including legislative frameworks, industry compliance, licensing and authorization procedures, verification and monitoring systems and control scope. Understanding these elements will enable stakeholders to support responsible and peaceful transfers of nuclear technology while ensuring compliance with international commitments and nonproliferation standards. The paper further delves into the context of these regimes, which are constructed in a way that provides cushion to the international community led by the Western states. The article emphasizes the critical role of the mechanisms of nuclear export control in preserving international security by preventing the unauthorized transfer of sensitive nuclear materials and technology. It also emphasizes the need for industry and national collaboration in this regard.

저출산 시대 모성에 대한 고찰

Today, Korean society is facing a crisis of low birth rate. Conflict between men and women caused by an intense competitive system and conservative familism is cited as a major cause of the low birth rate problem, which has emerged as a national issue. Radical feminism, which is considered an ideological background that influenced the conflict between men and women, emerged as a backlash against the government's reproductive policy that instrumentalizes motherhood, but its argument for liberation from motherhood is becoming a cause of social conflict. At a time like this, discovering a new positive view of motherhood and its value has important implications. Even within feminism, there is not only a perspective that views motherhood as a control mechanism for women and advocates liberation from motherhood. Since the 1980s, efforts have been made to understand motherhood more diversely within feminism, and there is a movement to present motherhood as a social value by discovering the value of care within motherhood. This perspective is believed to have a positive meaning by presenting the area of care as a common area for men and women and highlighting the ‘right to care’ of the vulnerable in a fiercely competitive society. However, in order for care to become an important value for both men and women, it is necessary to properly understand the value of care within motherhood. The personalist perspective, which understands motherhood as an outstanding attribute of women and shows a complementary relationship between men and women, will help men participate more actively in the area of care by learning about fatherhood through motherhood.

INFLUENCE OF INFORMATION TECHNOLOGY ON INTERNAL CONTROL SYSTEMS IN TERTIARY INSTITUTIONS IN OSUN STATE, NIGERIA

The study examined how information technology affects internal control systems in tertiary institutions in Osun State. Specific goals were to ascertain whether or not information technology has a significant impact on the internal control systems and internal audit processes of tertiary institutions. A survey research design was chosen. A sample size of 100 respondents participated in the study. This study used the stratified sampling method and a regression technique was used for data analysis. The findings showed that internal control systems and internal audit procedures in tertiary institutions in Osun State were highly influenced by information technology with t= 20.02 P< 0.0 and t= 19.049p<0.05, respectively. It was concluded that internal control systems and internal audit procedures at tertiary institutions were strengthened and improved by information technology. The study has recommended that tertiary institutions adopt information technology in order to improve their internal control frameworks. To keep their staff’s necessary skills and knowledge current, the management of tertiary institutions should encourage both on-the-job and off- the-job training in information technology. To stop fraud, internal control mechanisms should be put in place. To establish who will be held accountable for violations, tasks must be digitally separated effectively.

OEDG: Oscillation-eliminating discontinuous Galerkin method for hyperbolic conservation laws

Suppressing spurious oscillations is crucial for designing reliable high-order numerical schemes for hyperbolic conservation laws, yet it has been a challenge actively investigated over the past several decades. This paper proposes a novel, robust, and efficient oscillation-eliminating discontinuous Galerkin (OEDG) method on general meshes, motivated by the damping technique (see J. Lu, Y. Liu, and C. W. Shu [SIAM J. Numer. Anal. 59 (2021), pp. 1299–1324]). The OEDG method incorporates an oscillation-eliminating (OE) procedure after each Runge–Kutta stage, and it is devised by alternately evolving the conventional semidiscrete discontinuous Galerkin (DG) scheme and a damping equation. A novel damping operator is carefully designed to possess both scale-invariant and evolution-invariant properties. We rigorously prove the optimal error estimates of the fully discrete OEDG method for smooth solutions of linear scalar conservation laws. This might be the first generic fully discrete error estimate for nonlinear DG schemes with an automatic oscillation control mechanism. The OEDG method exhibits many notable advantages. It effectively eliminates spurious oscillations for challenging problems spanning various scales and wave speeds, without necessitating problem-specific parameters for all the tested cases. It also obviates the need for characteristic decomposition in hyperbolic systems. Furthermore, it retains the key properties of the conventional DG method, such as local conservation, optimal convergence rates, and superconvergence. Moreover, the OEDG method maintains stability under the normal Courant–Friedrichs–Lewy (CFL) condition, even in the presence of strong shocks associated with highly stiff damping terms. The OE procedure is nonintrusive, facilitating seamless integration into existing DG codes as an independent module. Its implementation is straightforward and efficient, involving only simple multiplications of modal coefficients by scalars. The OEDG approach provides new insights into the damping mechanism for oscillation control. It reveals the role of the damping operator as a modal filter, establishing close relations between the damping technique and spectral viscosity techniques. Extensive numerical results validate the theoretical analysis and confirm the effectiveness and advantages of the OEDG method.

Influence of heat treatment and forming cycle on the precise forming of AZ31 magnesium alloy sheet

Precision forming of 3 mm thick rolled AZ31 magnesium alloy sheet at 90° results in severe cracking and a considerable rebound angle. The effects of different sheet heat treatments and changes in the forming cycle on the value of the forming angle were investigated using 90° precision forming tests. The reasons of sheet cracking were examined using tensile tests and numerical simulations. Microscopic analysis and characterization techniques such as metallographic experiments, SEM observations, and EBSD tests are used to clarify the mechanism of improvement and control of the forming angle value. The results indicate that annealing treatment exhibits high sensitivity to controlling sheet cracking, but low sensitivity to controlling rebound. Among them, after heat treatment at 250 °C+1 h, the sheet no longer cracks during forming. In incomplete annealing, the more small grains produced by recrystallization and the greater the number of dimples in the fracture, the closer the forming angle is to 90°. Full annealing can result in a small reduction in the forming angle value compared to incomplete annealing treatments. After extending the forming cycle for 1 h, the increase in the ratio of dual tensile twin boundaries and low angle grain boundaries resulted in a significant decrease in the value of the forming angle and no cracking of the sheet. The increase of recrystallized tissue on the tensile side and the increase of the KAM value led to the decrease of the forming angle value to the minimum value at 300 °C+1 h heat treatment condition.

Adaptive task migration strategy with delay risk control and reinforcement learning for emergency monitoring

The timely and reliable handling of post-disaster emergency monitoring tasks is crucial for effective rescue operations. UAV-assisted edge computing plays a pivotal role in the rapid deployment of such systems. However, challenges persist due to communication and computation resource bottlenecks when dealing with delay-sensitive monitoring tasks. In dynamic post-disaster environments, effective task scheduling and resource allocation decisions directly impact the system’s ability to process tasks. Therefore, this paper proposes an adaptive task migration decision-making system for emergency monitoring tasks in UAV-assisted edge computing. Firstly, We decomposed the optimization objectives based on the task processing workflow, then devised a stepwise delay risk control and resource recovery mechanism based on early discarding. Secondly, by integrating multi-agent reinforcement learning (MARL), optimal strategies for task offloading, UAV queue scheduling, and communication resource allocation are learned to enhance the decision system’s environmental awareness and maximize the successful completion of emergency monitoring tasks. Simulation experiments demonstrate that the algorithm significantly improves the success rate of migration tasks and data processing capacity, thereby validating its convergence and effectiveness.