System Subject Research Articles

A Finite-Time Disturbance Observer for Tracking Control of Nonlinear Systems Subject to Model Uncertainties and Disturbances

In this study, a finite-time disturbance observer (FTDOB) with a new structure is originally put forward for the motion tracking problem of a class of nonlinear systems subject to model uncertainties and exogenous disturbances. Compared to existing disturbance estimator designs in the literature, in which the estimation error only converges to the origin asymptotically under assumptions that the first and/or second derivatives are vanishing, the suggested DOB is able to estimate the disturbance exactly in finite time. Firstly, uncertainties (parametric and unstructured uncertainties), unknown dynamics, and external disturbances in system dynamics are lumped into a generalized disturbance term that is subsequently estimated by the proposed DOB. Based on this, a DOB-based backstepping controller is synthesized to ensure high-accuracy tracking performance under various working conditions. The stability analysis of not only the DOB but also the overall closed-loop system is theoretically confirmed by the Lyapunov stability theory. Finally, the advantages of the proposed FTDOB and the FTDOB-based controller over other DOBs and existing DOB-based controllers are explicitly simultaneously demonstrated by a series of numerical simulations on a second-order mechanical system and comparative experiments on an actual DC motor system.

Prescribed‐time distributed optimization for multi‐agent system subject to inequality constraints

Prescribed‐time distributed optimization for multi‐agent system subject to inequality constraints

Augmented Reality-Based Learning Media in Computer Systems Subjects

This research aims to develop Augmented Reality (AR)-based learning media in the Computer Systems subject at SMK Negeri 2 Argamakmur, with the hope of increasing the effectiveness and involvement of students in the learning process. This study uses the Research method and Development (RD) with the ADDIE (Analysis, Design, Development, Implementation, and Evaluation) development model. The subjects of the study consisted of 30 grade XI students at SMK Negeri 2 Argamakmur. Data collection instruments included questionnaires to measure student and teacher responses, and tests to assess the increase in conceptual understanding. The media feasibility test was carried out through validation by material experts and media experts, as well as limited trials. The results showed that AR-based learning media received a "very feasible" rating from material experts with a score of 88.5% and from media experts with a score of 91.2%. Testing the effectiveness of the media on student understanding showed an increase in learning outcomes with an average pre-test score of 65.3 increasing to 82.7 in the post-test, with a rise of 26.5%. Student responses to this learning media were also very positive, with a percentage of satisfaction reaching 89.4%. Based on these results, it can be concluded that the AR-based learning media developed effectively improves student understanding and can be used as a learning medium in the computer systems subjects.

Command-Filter-Based Predefined-Time Control for State-Constrained Nonlinear Systems Subject to Preassigned Performance Metrics

Command-Filter-Based Predefined-Time Control for State-Constrained Nonlinear Systems Subject to Preassigned Performance Metrics

Energy Efficiency Optimization of FBMC/OQAM-Based Massive MIMO Systems Subject to Electromagnetic Exposure Constraints

Energy Efficiency Optimization of FBMC/OQAM-Based Massive MIMO Systems Subject to Electromagnetic Exposure Constraints

Finite-Time Fuzzy Preassigned-Performance Control for Nonlinear Systems Subject to Asymmetric State-Constraints Based on Command Filter

Finite-Time Fuzzy Preassigned-Performance Control for Nonlinear Systems Subject to Asymmetric State-Constraints Based on Command Filter

Decision Function-Based Adaptive Control of Uncertain Systems Subject to Irregular Output Constraints

Decision Function-Based Adaptive Control of Uncertain Systems Subject to Irregular Output Constraints

Directionality theory and the origin of life.

The origin of cellular life can be described in terms of the transition from inorganic matter to the emergence of cooperative assemblies of organic matter: DNA and proteins, capable of replication and metabolism. Directionality theory is a mathematical theory of the collective behaviour of networks of organic matter: activated macromolecules, cells and higher organisms. Evolutionary entropy, a generalization of the thermodynamic entropy of Boltzmann, is a statistical measure of the cooperativity of the biotic components. The cornerstone of Directionality theory is the Entropic Principle of Evolution: evolutionary entropy increases in systems driven by a stable energy source, and decreases in systems subject to a fluctuating energy source. This article invokes the Entropic Principle of Evolution-an extension to biological systems of the Second Law of Thermodynamics-to provide an adaptive rationale for the following sequence of transformations that define the emergence of cellular life: (i) the self-assembly of activated macromolecules from inorganic matter; (ii) the emergence of an RNA world, defined by RNA molecules with catalytic and replicative properties; and (iii) the origin of cellular life, the integration of the three carbon-based polymers-DNA, proteins and lipids, to generate a metabolic and replicative unit.

Event-Triggered-Based Adaptive Fuzzy Finite-Time Resilient Output Feedback Control for MIMO Stochastic Nonlinear System Subject to Deception Attacks

Event-Triggered-Based Adaptive Fuzzy Finite-Time Resilient Output Feedback Control for MIMO Stochastic Nonlinear System Subject to Deception Attacks

Algorithmic modelling of a complex redundant multi-state system subject to multiple events, preventive maintenance, loss of units and a multiple vacation policy through a MMAP

Algorithmic modelling of a complex redundant multi-state system subject to multiple events, preventive maintenance, loss of units and a multiple vacation policy through a MMAP

The Effect of Using Technology-Assisted Drama Method in Teaching the Central Nervous System Subject on Academic Achievement and Attitude

The aim of this research is to examine the effect of technology-supported drama method applications on students' academic achievements regarding the central nervous system and their attitudes towards biology. In the research, quasi-experimental design with pre-test post-test control group, one of the quantitative research methods, was used. The sample of the research consists of a total of 50 students studying in biology course at a state university, in 2 classes determined by the convenient sampling method. The subjects covered within the scope of the research were taught with the traditional teaching method in the control group and with the technology-supported drama method in the experimental group. As a data collection tool in the research, the "Academic Achievement Test" developed by Akman (2023) and Geban, Ertepınar, Yılmaz, Altın, were used to measure the academic achievements of the students. and the Biology Attitude Scale, developed by Şahbaz (1994) to determine students' attitudes towards chemistry and modified as a biology attitude scale by Pekel (2005), were used. SPSS 22.0 package program was used to analyze the data. As a result of the research, it was determined that the course carried out with the technology-supported drama method generally positively increased the academic success and attitudes of the students.

The Practicality of STEAM Based Augmented Reality (AR) Learning Media for Vocational High School Students in Robotic System Subject

This study aims to create and implement STEAM-based Augmented Reality (AR) learning media for the class XI robotics systems curriculum at SMK N 1 West Sumatra. The research follows a Research and Development (R&D) approach using the ADDIE development model. Participants included class XI students and robotics systems teachers. Data collection methods comprised questionnaires and interviews, with descriptive data analysis employed to assess the validity and practicality of the developed learning media. The findings indicate that the STEAM-based AR learning media is effective. According to media expert validation, the average score was 0.88 (≥ 0.66), categorizing it as valid. Material expert validation yielded an average score of 0.85 (≥ 0.66), also marking it as valid. The practicality assessment showed that teacher responses averaged 90.14%, and student responses averaged 92.03%, both rated as very practical. Consequently, the STEAM-based AR learning media is considered suitable for class XI robotics systems at SMK N 1 West Sumatra, based on the validity and practicality tests

Why aren't we teaching this? Smart local energy systems and the young person's perspective

AbstractWith the UK government's target of Net Zero by 2050, alongside the rising cost of energy in the UK, it is imperative that public opinion aligns with and promotes affordable, greener energy systems. Within this dialogue, young people's voices and lived experience are needed to deepen the impact of energy policy intervention strategies. This article stresses the importance of a formal curriculum that informs future generations on the subjects of Smart Local Energy Systems (SLES), and the digitalisation advances of energy systems. This paper explores the development of a toolkit to educate and engage young people in these subjects and reviews young people's attitudes and understanding from three schools in England, UK. We find through an interpretive qualitative analysis of both images drawn by the young people, and insights gathered from focus groups, that (i) for these young people, SLES are a useful innovation regarding energy management and distribution, (ii) young people recognise that the education system as it currently stands is not aware of, or informed by smart energy technologies and (iii) that despite being a generation that is the most integrated with personal assistance technology, these young people have significant concerns over the reliability and safety of AI in SLES. These findings are set alongside calls for widespread education in key stages 4 and 5 (ages 14–18) around the subject of SLES, and their benefits to wider society, thereby enabling a future that empowers young people to make change, encourage engineering and computer science‐based career options and secure a fairer, cleaner, sustainable energy transition in the future.

Secure Multiplicative Sampled-Data Control for T-S Fuzzy-Based Cyber-Physical Systems Subject to Deception Attacks

Secure Multiplicative Sampled-Data Control for T-S Fuzzy-Based Cyber-Physical Systems Subject to Deception Attacks

PENGEMBANGAN LEMBAR KERJA PESERTA DIDIK BERBASIS DISCOVERY LEARNING PADA MATERI SISTEM PENCERNAAN MANUSIA

The background to this research is the development of student worksheets based on Discovery Learning. This research aims to produce interactive learning media products on the human digestive system that are valid, practical and effective. This type of research is the development of the PLOMP model. The research method used in this research is research and development. This research was tested on 20 class VIII students at SMP Negeri 1 O'o'u. To standardize products, three test stages are carried out, namely: validity test, practicality test, effectiveness test. The instruments used are assessment questionnaires using a Likert scale and evaluation test questions to determine student learning outcomes. The research results show that the Discovery Learning-based LKPD is very valid with a presentation of 85% and is suitable for use. The average value of practicality assessed by teachers is 3.48 and students are 3.64 in the very practical category. Student motivation results are at 86% with a cognitive average of 88.7. The suggestion given by the researcher is that science-biology subject teachers should use LKPD as teaching materials in the teaching and learning process because it can increase students' interest and motivation to learn. Through this teaching material, students can broaden their horizons regarding science-biology learning on the subject of the human digestive system. For future researchers, this student worksheet can be used as reference material in research

Adaptive Predefined‐Time Fuzzy Control for Nonlinear Systems Subject to Unknown Control Direction and Mismatched Disturbances Based on Command Filter Technique

ABSTRACTThis article proposes an adaptive predefined‐time event triggered fuzzy tracking control strategy for strict‐feedback nonlinear systems with unknown control direction and mismatched disturbances by applying command filters. The Nussbaum‐type function is employed to tackle the unknown control direction problem, and the fuzzy logic systems (FLSs) are applied to model the nonlinear functions. And then, command filters are adopted to deal with the problems of complexity explosion, and the event‐triggered technique is exploited to conserve communication resources. With the help of backstepping mechanism and predefined‐time stability theory, the constructed adaptive control scheme is proposed to ensure all signals in the closed‐loop system are bounded and that the tracking error converges to a residual set. Finally, a simulation example proves the validity of presented control mechanism.

Adaptive Fixed-Time Command-Filtered Fuzzy Control for Nonlinear Stochastic Systems Subject to Saturating Input and Its Application to the Electromechanical System

Adaptive Fixed-Time Command-Filtered Fuzzy Control for Nonlinear Stochastic Systems Subject to Saturating Input and Its Application to the Electromechanical System

Modern Approaches to Attracting Personnel to Medical Organizations in Rural Areas on an Example of the Voronezh Region

INTRODUCTION: The importance of this study stems from the necessity to search for an effective solution to the problem of provision of the rural healthcare with medical personnel to increase the quality of medical care and its availability for the population. AIM: To scientifically substantiate and develop proposals for attracting and developing the human resources potential of rural medical organizations. MATERIALS AND METHODS: To assess the state of provision of healthcare in the Voronezh Region (VR) with human resources, the data from statistical accounting forms No. 17 and No. 30 were used. The comparative analysis method was used to study the provision of medical organizations of the VR with medical personnel and staffing with medical positions, and the main parameters of the activity of medical organizations in rural areas of the region. To study the factors contributing to the attraction of young specialists to medical organizations in rural areas, an anonymous online survey was conducted. RESULTS: The analysis of provision of healthcare organizations of the VO with personnel showed a satisfactory level of provision with medical workers. The personnel shortage is more pronounced in rural areas the staffing of full-time positions is decreasing, the influx of young specialists is decreasing, the proportion of people of retirement age is increasing. In-depth analysis permitted to identify ‘weak points’ in the formation of the personnel reserve and take them into account when forming the regional personnel policy. Based on the data obtained during the study, a multi-level model of reproduction of human resources was created using the cluster approach. A mechanism for interaction between potential employers and subjects of the educational system was developed. CONCLUSION: The pooling of resources within the framework of cluster interdepartmental interaction led to the expansion of the career guidance space and permitted to build practice-oriented educational activities based on continuity of general, secondary vocational and higher education. The findings of the study can be used in the formation of an effective personnel policy aimed at advanced forecasting of the process of their reproduction in the healthcare system.

Modelling the effect of free convection on permafrost melting rates in frozen rock clefts

Abstract. This research develops a conceptual model of a karst system subject to mountain permafrost. The transient thermal response of a frozen rock cleft after the rise in the atmospheric temperature above the melting temperature of water is investigated using numerical simulations. Free convection in liquid water (i.e. buoyancy-driven flow) is considered. The density increase in water from 0 to 4 °C causes warmer meltwater to flow downwards and colder upwards, resulting in significant enhancement of the heat transferred from the ground surface to the melting front. Free convection increases the melting rate by approximately an order of magnitude compared to a model based on thermal conduction in stagnant water. The model outcomes are compared qualitatively with field data from the Monlesi ice cave (Switzerland) and confirm the agreement between real-world observations and the proposed model when free convection is considered.

Event Based Control for Network Security Systems Subject to Actuator Saturation

Abstract As a typical nonlinear link, actuator saturation exists in most network security protection systems. It easily disrupts the closed-loop performance of the system, leading to instability. The event triggering control policy generally adopts an aperiodic sampling mechanism and transmits information only when the triggering condition is met, which can save system communication and computing resources. An event-triggered controller is designed for a network security system with actuator saturation, and the system stabilization is realized. The attractor domain of the system is estimated by solving optimization problems in the form of linear matrix inequalities. Simulation results show the validity of the conclusions obtained in this paper.