Design Of Systems Research Articles

Non-fragile tracking controller design for fractional order systems against active disturbance rejection

Non-fragile tracking controller design for fractional order systems against active disturbance rejection

Optimal Strictly Stealthy Attack Design on Cyber-Physical Systems: A Data-Driven Approach.

In this article, an issue of data-driven optimal strictly stealthy attack design for the stochastic linear invariant systems is investigated, with the aim of maximizing the system performance degradation under an energy bounded constraint and bypassing the parity-space-based attack detector. Importantly, the proposed attack policy refrains from the assumption that the system knowledge is known to attackers. A novel strictly stealthy attack sequence (SSAS), coordinating the sensor and actuator signals simultaneously, is proposed with a sufficient and necessary condition for the existence of such an attack presented. Specifically, the SSAS is parameterized as a vector in the null space of a specific matrix which is constructed by a parity matrix and the system Markov parameters. For the purpose of data-driven attack realization, modified subspace identification methods are utilized to achieve an unbiased estimation of the required parameters via the closed-loop data. On this basis, the attack design is formulated as a constrained optimization problem, an explicit solution to which is given to characterize the optimal strictly stealthy attack. Finally, the vulnerability of the cyber-physical systems is analysed from the perspective of the parameter selection for the parity space-based detector. A case study on a three-tank model verifies the efficiency of the proposed approach.

Thermally Activated Delayed Fluorescence (TADF) Materials Based on Earth-Abundant Transition Metal Complexes: Synthesis, Design and Applications.

Materials exhibiting thermally activated delayed fluorescence (TADF) based on transition metal complexes are currently gathering significant attention due to their technological potential. Their application extends beyond optoelectronics, in particular organic light-emitting diodes (OLEDs) and light-emitting electrochemical cells (LECs), and include also photocatalysis, sensing, and X-ray scintillators. From the perspective of sustainability, earth-abundant metal centers are preferred to rarer second- and third-transition series elements, thus determining a reduction in costs and toxicity but without compromising the overall performances. This review offers an overview of earth-abundant transition metal complexes exhibiting TADF and their application as photoconversion materials. Particular attention is devoted to the types of ligands employed, helping in the design of novel systems with enhanced TADF properties.

A Correlation‐Based Prediction Method of Heat Transfer Coefficients for Flooded Evaporation on Enhanced Tubes

AbstractHeat transfer in evaporation units play a vital role in the design and optimization of heat pumps and refrigeration systems. Existing correlations are often limited to the respective heat transfer surface. Furthermore, the majority of correlations reported have a lack of reliable validation beyond the test of their ability to describe the data they have been fitted to. In the present study, the heat transfer in case of flooded evaporation on an enhanced tube was examined for two refrigerants and propane. The experimentally measured data were used to develop a new correlation for the shell‐side heat transfer. The correlation was assessed on a separate test set, not utilized in the process of model development. The correlation and procedure are reliable and transferable tools for estimation of heat transfer in enhanced tube evaporators for refrigerants.

Design and Analysis of Various Formwork Systems

Concrete is a fundamental material in the construction industry, with formwork playing a crucial role in shaping and strengthening concrete elements. It also represents a significant cost in building projects. The history of formwork is extensive, and diverse systems have been employed across various projects. When selecting a formwork system, considerations such as safety, cost, structural requirements, construction duration, and environmental impact must be carefully weighed. This project provides a comprehensive review of different formwork systems used in concrete construction, encompassing their materials, flexibility, fabrication methods, application in structures, and environmental implications. The advantages and limitations of these systems are analysed and compared, culminating in practical recommendations. Formwork systems are pivotal in determining the success of construction projects in terms of efficiency, quality, cost-effectiveness, and safety. Recent innovations, particularly modular formwork systems, have revolutionized the construction industry in countries like Japan, Singapore, Malaysia, and the Middle East. These systems have proven to be cost- effective, enhance construction quality, and accelerate project timelines. Their adaptability makes them particularly suitable for mass construction projects in India, where achieving high-quality, rapid construction is crucial. By leveraging modern formwork technologies, construction practices can achieve safer, faster, and more sustainable outcomes, aligning with advancements

Experimental and Numerical Study of Newly Assembled Lightweight Radiant Floor Heating System

In this study, the heating capacity of a new prefabricated assembled hot water radiant modular heating system made from a recycled waste building masonry structure is investigated through experimental and numerical simulation methods. The heating capacity of the system in different working conditions (a water supply temperature of 48 °C, 51 °C, 56 °C, and 61 °C; a flow rate of 0.49 m3/h, 0.35 m3/h, and 0.21 m3/h) is analyzed and verified. A three-dimensional steady-state heat transfer numerical model of the floor heat transfer of the module is established, and the accuracy of the model is verified through the measured results to investigate the heating capacity of this system under different water supply temperatures, flow rates and coil spacings. The results show that the new prefabricated hot water radiant module heating system has a 0.9 °C higher air temperature and 2.1 °C higher average floor surface temperature than the traditional wet floor radiant heating system under the same experimental conditions, and the response time is 44% shorter. The water supply temperature can significantly change the heating capacity of the system, while the water supply flow rate has little effect on the system. The established three-dimensional steady-state numerical model can be in good agreement with the measured results. This study can provide an experimental and theoretical basis for the design and application of such systems.

Synchronised WindScanner field measurements of the induction zone between two closely spaced wind turbines

Abstract. Field measurements of the flow interaction between the near wake of an upstream wind turbine and the induction zone of a downstream turbine are scarce. Measuring and characterising these flow features in wind farms under various operational states can be used to evaluate numerical flow models and design of control systems. In this paper, we present induction zone measurements of a utility-scale 3.5 MW turbine with a rotor diameter of 126 m in a two-turbine wind farm operating under waked and unwaked conditions. The measurements were acquired by two synchronised continuous-wave WindScanner lidars that could resolve longitudinal and lateral velocities by dual-Doppler reconstruction. An error analysis was performed to quantify the uncertainty in measuring complex flow situations with two WindScanners. This is done by performing a large-eddy simulation while using the same measurement layout, modelling the WindScanner sensing characteristics and simulating similar inflow conditions observed in the field. The flow evolution in the induction zone of the downstream turbine was characterised by performing horizontal-plane dual-Doppler scans at hub height. The measurements were conducted for undisturbed, fully waked and partially waked flows. Evaluation of the engineering models of the undisturbed induction zone showed good agreement along the rotor axis. In the full-wake case, the measurements indicated a deceleration of the upstream turbine wake due to the downstream turbine induction zone as a result of the very short turbine spacing. During a wake steering experiment, the interaction between the laterally deflected wake of the upstream turbine and the induction zone of the downstream turbine could be measured for the first time in the field. Additionally, the analyses highlight the affiliated challenges while conducting field measurements with synchronised lidars.

Event‐triggered fault detector design in networked fuzzy control systems under denial‐of‐service attacks

Event‐triggered fault detector design in networked fuzzy control systems under denial‐of‐service attacks

Investigation of normal zone propagation velocity in AgSn/Ag/Ba122 superconducting tapes using a conduction cooling test system

Abstract The investigation of the behavior of normal zone propagation in iron-based superconducting (IBS) tapes is important for their application in magnets and the design of quench protection systems. However, little research has been done in this area. In this work, a conduction cooling test system for IBS tapes and coils has been built, which has functions such as charging test, temperature and voltage data acquisition, pulse current heating, quench detection and protection. A series of experiments were performed on several 27 cm long IBS tapes to measure their normal zone propagation velocity (NZPV). The variation trends of NZPV with different operating temperatures, and with different ratios of operating current to critical current were systematically explored. In addition, monitoring all the voltages between different positions of an IBS tape, including two joints, has provided more detailed results and findings.

Novel Dynamic Defense Strategies in Networked Control Systems under Stochastic Jamming Attacks

In contemporary networked control systems (NCSs), ensuring robust and adaptive security measures against dynamic threats like jamming attacks is crucial. These attacks can disrupt the control signals, leading to degraded performance or even catastrophic failures. This paper introduces a novel approach to enhance NCS security by applying stochastic game theory to model and resolve interactions between a defender and a jammer. We develop a two-player zero-sum game where the defender employs mixed strategies to minimize the expected cost of maintaining system stability and control effectiveness in the face of potential jamming. Our model discretizes the state space and employs backward induction to dynamically update the value functions associated with various system states, reflecting the ongoing adjustment of strategies in response to the adversary’s actions. Utilizing linear programming in MATLAB, we optimize the defender’s mixed strategies to systematically mitigate the impact of jamming. The results from extensive simulations demonstrate the efficacy of our proposed strategies in attack scenarios, indicating a substantial enhancement in the resilience and performance of NCSs against jamming attacks. Specifically, the proposed method improved network state stability by 75%, reducing the fluctuation range by over 50% compared with systems without defense mechanisms. This study not only advances the theoretical framework for security in NCSs but also provides practical insights for the design of resilient control systems under uncertainty.

Multi‐objective assessment of the water‐energy‐environment‐food nexus involving a life cycle assessment approach

AbstractThis work addresses the multi‐objective design of water, energy and food supply systems in isolated rural communities using local resources. The approach used considers objective functions based on life cycle analysis such as water and carbon footprint, as well as economic performance considering the application and integration of normalized metrics to address the water‐energy‐environment‐food nexus. The results show that it is possible to build robust and accessible metrics for the analysis of problems with various design objective functions in decision‐making environments. The optimization problem considers decision variables associated with the sizing of units such as photovoltaic panels, wind turbines, thermal and electrical energy storage, wood‐fired boilers and the integration of food production systems involving aquaculture and local corn production. Water management is associated with domestic activities and crop irrigation.

Autonomous military systems beyond human control: putting an empirical perspective on value trade-offs for autonomous systems design in the military

Autonomous military systems beyond human control: putting an empirical perspective on value trade-offs for autonomous systems design in the military

Electric vehicle charging technologies, infrastructure expansion, grid integration strategies, and their role in promoting sustainable e-mobility

The transport sector is experiencing a notable transition towards sustainability, propelled by technological progress, innovative materials, and a dedication to environmental preservation. This study explicitly examines the incorporation of electric vehicles (EVs) into the power grid, with a particular emphasis on passenger automobiles. Our analysis emphasises the vital importance of updated transport infrastructure in decreasing greenhouse gas emissions and aiding carbon reduction efforts in electricity networks. The analysis uncovers that adopting electric vehicles offers significant advantages, including enhanced grid efficiency and decreased emissions. However, it also brings issues concerning the design and operation of power systems at both the transmission and distribution levels. Key players are crucial in tackling these difficulties to improve electric vehicle integration into the grid. The study determines the most effective ways for distributing and providing electric vehicle charging infrastructure, and investigates the efforts made to establish common standards in order to solve current challenges. This research contributes to the advancement of sustainable mobility and energy systems by conducting a thorough examination of the impact of electric vehicles on power systems and offering appropriate integration solutions.

Exploring the Influence of Pore Shape on Conductance and Permeation

There are increasing numbers of ion channel structures featuring heteromeric subunit assembly, exemplified by synaptic α1βB Glycine and α4β2 Nicotinic receptors. These structures exhibit inherent pore asymmetry, but the relevance of this to function is unknown. Furthermore, molecular dynamics simulations performed on symmetrical homomeric channels often leads to thermal distortion whereby conformations of the resulting ensemble are also asymmetrical. When functionally annotating ion channels, researchers often rely on minimal constrictions determined via radius-profile calculations performed with computer programs, such as HOLE or CHAP, coupled with an assessment of pore hydrophobicity. However, such tools typically employ spherical probe particles, limiting their ability to accurately capture pore asymmetry. Here, we introduce an algorithm that employs ellipsoidal probe particles, enabling a more comprehensive representation of the pore geometry. Our analysis reveals that the use of non-spherical ellipsoids for pore characterization, provides a more accurate and easily interpretable depiction of conductance. To quantify the implications of pore asymmetry on conductance, we systematically investigated carbon nanotubes (CNTs) with varying degrees of pore asymmetry as model systems. The conductance through these channels shows surprising effects that would otherwise not be predicted with spherical probes. The results have broad implications not only for the functional annotation of biological ion channels, but also for the design of synthetic channel systems for use in areas such as water filtration. Furthermore, we make use of the more accurate characterization of channel pores to refine a physical conductance model to obtain a heuristic estimate for single channel conductance. The code is freely available, obtainable as pip-installable python package and provided as a webservice.

Fly-around-the-World Near-Space Picosatellite for Cost-Effective School Space Projects

This research presents the design and development of a near-space picosatellite platform intended to operate at high altitudes between 20–40 km above sea level. These picosatellites function similarly to orbital satellites but float and travel with the wind in the atmosphere instead of orbiting the Earth. The platform utilizes a super-pressure balloon to provide buoyancy, allowing the picosatellite to remain airborne and operational for several days to months, capable of flying around the world multiple times. This study focuses on the cost-effective design of high-altitude platforms, telecommunication systems, and energy consumption for the picosatellite, enabling it to communicate with ground stations from anywhere in the world while consuming low power. The use of common COTS (Commercial Off-The-Shelf) equipment aims to enhance accessibility for educational applications. This research gathered data from our previous studies for over 20 high-altitude platform flights, analyzed the necessary factors for whole system design, and developed a new prototype that has been successfully built and tested.

Teaching content model for designing digital systems of power grid relay protection and automation

It was found that the effective formation of conceptual-analytical and productive-synthetic levels of formation of professional knowledge and skills regarding the design of digital systems of power grid relay protection and automation is possible with the systematic development and use of a generalized model of the teaching content. Based on the study of information models of technical systems, a feature model was adopted as a basic invariant, which includes a set of features of the purpose, construction, principle of operation and parameters of the technical system. It was found that the design process of digital systems of power grid relay protection and automation can be conventionally divided into three stages, namely, the development of the design task, the direct implementation of the design, and the determination of the parameters of operation. Causal chains of knowledge that form the basis of problem solving at these three stages are determined. It was found that the methods of step-by-step decomposition and aggregation are key in building the content of teaching the design of digital systems of power grid relay protection and automation based on causal chains of knowledge. A generalized model of the teaching content design of digital systems of power grid relay protection and automation based on causal chains of knowledge is substantiated. According to the generalized model, the teaching content design of specific microprocessor l systems of power grid relay protection and automation has been developed. With the help of experimental verification, the effectiveness of the teaching content design of digital systems of relay protection and automation based on causal chains of knowledge has been proven. The results of the research can be used in the educational process of professional training of future engineers in the specialty 141 Electric power, electrical engineering and electromechanics.

Investigating the Actuation of Sidewall Sprinkler in an Atrium Using CFD Simulation

This study investigates the actuation of sidewall sprinklers in large-scale buildings with high-ceilinged atriums, addressing the challenges of unique architectural configurations. Compliance with NFPA 101 requires automatic sprinkler systems, including atrium areas, in these buildings. To maintain aesthetic considerations, design engineers, particularly in the middle east, often propose sidewall sprinklers as an alternative to traditional ceiling sprinklers. This research assesses whether the sidewall sprinklers would actuate during a fire using Fire Dynamic Simulator (FDS). The findings indicate that sidewall sprinklers will fail to actuate if the fire is located at the centre of the atrium, even if the edge of the fire area is below the sprinklers. Furthermore, the study emphasizes the importance of using an FDS mesh resolution (D*/dx) of 6 or finer resolution when measuring temperatures near the flame or fire plume to ensure accurate evaluations of sprinkler activation. These findings provide valuable insights for design engineers and authorities, assisting in decision-making processes related to fire safety measures, system designs, and regulatory compliance.

Scalable and effіciant digital twins for model-based design of cyber-physical systems

ABSTRACT The optimised design, operation and management of complex, large-size Cyber Physical Systems (CPSs) – like modern manufacturing and logistic assets – calls for Digital Twins (DTs) in which dynamic modelling and simulation play a relevant role. In such simulation-based DTs computational efficiency is crucial. According to the present state of the art, the said efficiency is hindered by the way the Cyber part of a CPS is represented, which in the manufacturing case practically corresponds to representing digital controls. This paper proposes a modelling framework for an efficient and scalable representation of the Cyber part in a DT of a CPS. The presented solution is based on Object-Oriented Modelling (OOM) and IEC industrial standards. Motivating and explanatory examples are provided, and a proof-of-concept case study is discussed to support the framework potential and industrial viability.

Methods for calculating the moisture discharge characteristics of insulators

This paper presents a detailed analysis and comparison of methods for calculating the moisture discharge voltage of insulators. The initial section provides a brief overview of the principles underlying air discharge along the surface of insulators, which is crucial for understanding moisture discharge processes. Two primary calculation methods for moisture discharge voltage are considered. The first method is based on Tepler's formula, which requires specific input data that can only be obtained experimentally. Although this approach is classical, it complicates practical application due to the difficulty of acquiring the necessary parameters under real-world conditions. The second method, described in the literature, relies on readily available data, significantly simplifying the calculation process. Based on this method, an automated tool for calculating the moisture discharge characteristics of insulators has been developed. The use of this tool reduces dependency on experimental data, providing accurate results with minimal time and resource expenditure. To demonstrate the effectiveness of the proposed tool, a moisture discharge characteristic calculation was performed for the insulator type LK 70-110. According to the analysis results, the moisture discharge voltage for this insulator is 549 kV, with a stress of 2.1 kV per centimeter of leakage current path length. These figures align with the average values obtained using the first method, confirming the reliability and accuracy of the new approach. The conclusions indicate that the second calculation method is fully satisfactory for standard insulator calculations. It can also be applied in specific conditions, such as under-chemo-substations, where precision and efficiency are critically important. Thus, the proposed calculation method can become an effective tool for engineers and researchers involved in the design and analysis of insulation systems. This work significantly contributes to the development and improvement of methods for assessing the moisture discharge characteristics of insulators, representing an essential step towards enhancing the reliability and safety of electrical networks and their operation.

Smart Solutions for Sustainable Agriculture: Design and Development of IoT-Powered Soil Health Identification Systems

This research examines smart solutions for agricultural sustainability using IoT-powered soil health detection systems. Innovative solutions are needed to manage resources and protect the environment as the world population grows and agricultural resources are under strain. IoT-enabled soil health monitoring has great potential. The suggested system uses IoT sensors to measure soil moisture, pH, nutrient content, and temperature in real time. This data is analyzed using powerful data analytics and machine learning algorithms to provide farmers soil health information. Monitoring soil quality allows farmers to make educated irrigation, fertilization, and crop selection choices, optimizing resource use and yields while minimizing environmental effect. The study also examines sensor selection, data transmission methods, and data security for IoT-powered soil health detection systems. Widespread use of these technologies might boost agricultural output, lower input costs, and enhance food security. Finally, IoT-powered soil health detection systems are a major step toward agricultural sustainability. These devices enable precision farming that is ecologically friendly and profitable by giving real-time soil data. However, effective implementation would need agricultural value chain stakeholders to collaborate and continued research to address growing issues and possibilities.