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Patients are often switched between generic formulations of the same drug, but in some cases generic interchangeability is questioned. For generic drugs to be approved, bioequivalence with the innovator drug should be demonstrated, but evidence of bioequivalence is not required in the intended patient population or relative to other approved generics., Aim: We aim to identify pathophysiological pharmacokinetic subpopulations for whom there is a difference in comparative bioavailability compared to a healthy population., Methods: We used simulated exposures from a nonparametric model of multiple generics and the originator gabapentin. Exposure was simulated for virtual populations with pharmacokinetic characteristics beyond those of healthy subjects with regard to rate of absorption, volume of distribution and reduced renal function. Virtual parallel design bioequivalence studies were performed using a random sample of 24 simulated subjects, with standard acceptance criteria., Results: Results indicated increased pharmacokinetic variability for patient populations with a lower rate of absorption or a reduced renal function, but no change in the average comparable bioavailability ratio. This increased variability results in a reduced likelihood of demonstrating bioequivalence. Observations were similar for comparisons between all different formulations, as well as between subjects who received the identical formulation in a repeated fashion. No relevant effect was observed for simulations with increased volume of distribution., Conclusion: Our simulations indicate that the reduced likelihood of demonstrating bioequivalence for subjects with altered pharmacokinetics is not influenced by a formulation switch, nor does the average comparable bioavailability ratio change, therefore these results support generic interchangeability and current approval requirements for generics., (© 2022 The Authors. British Journal of Clinical Pharmacology published by John Wiley & Sons Ltd on behalf of British Pharmacological Society.)

Aims: Amikacin requires therapeutic drug monitoring for optimum efficacy; however, the optimal model-informed precision dosing strategy for the area under the concentration-time curve (AUC) of amikacin is uncertain. This simulation study aimed to determine the efficient blood sampling points using the Bayesian forecasting approach for early achievement of the target AUC range for amikacin in critically ill patients., Methods: We generated a virtual population of 3000 individuals using 2 validated population pharmacokinetic models identified using a systematic literature search. AUC for each blood sampling point was evaluated using the probability of achieving a ratio of estimated/reference AUC at steady state in the 0.8-1.2 range., Results: On day 1, the 1-point samplings for population pharmacokinetic models showed a priori probabilities of 26.3 and 45.6%, which increased to 47.3 and 94.4% at 23 and 15 h, respectively. Using 2-point sampling at the peak (3 and 4 h) and trough (24 h) on day 1, these probabilities further increased to 72.3 and 99.5%, respectively. These probabilities were comparable on days 2 and 3, regardless of 3 and 6 sampling points or estimated glomerular filtration rate. These results indicated the higher predictive accuracy of 2-point sampling than 1-point sampling on day 1 for amikacin AUC estimation. Moreover, 2-point sampling was a more reasonable approach than rich sampling., Conclusions: This study contributes to the development of an efficient model-informed precision dosing strategy for early targeting of amikacin AUC in critically ill patients., (© 2024 British Pharmacological Society.)

The heterocharge accumulated in the oil‐paper insulation system of the converter transformer will enhance the local electric field and cause insulation deterioration. Numerical simulation is an effective method to analyze heterocharge. Currently, the numerical simulation of heterocharge is mainly based on the bipolar charge transport (BCT) model and the impurity ion transport (IIT) model. However, the effects of temperature, conductivity, and thickness of oil‐impregnated paper on charge transport have not been considered in these models. In view of this, a modified charge transport (MCT) model by introducing the Maxwell–Wagner model and heat conduction equation is proposed in this paper based on the BCT model and IIT model. Then, the influence of multi‐factors (temperature gradient, moisture content, and oil‐impregnated paper thickness) on heterocharge accumulation is investigated by using the MCT model. The simulation results obtained by the MCT model are more consistent with the experimental results than the BCT model, which proves the accuracy and superiority of the MCT model. Moreover, the increase in temperature gradient, moisture content, and oil‐impregnated paper thickness will enlarge the ion dissociation rate, conductivity, and trap density, and thus promote the generation of heterocharge. In that respect, the MCT model is expected to optimize the insulation design and provide a reference for space charge dynamic simulation. [ABSTRACT FROM AUTHOR]

In this paper, we propose a method of generating the elemental image array (EIA) for the integral imaging (InIm) based light field display (LFD). Firstly, we reveal the intrinsic voxel spatial distributions of the InIm‐based LFD and analyze how the voxel space affects the display performances such as spatial resolution, depth of field, and smoothness of parallax. Then, we present an algorithm to generate an EIA from a pair of RGB and depth (RGBD) images and an optimally selected voxel space. In the experiments, we tested the display performances of the voxels on different depth planes and obtained results consistent with the theoretical analyses. We also experimented with a computer 3D model and a real‐world scene on two InIm‐based LFD prototypes working in different modes, one in real mode and the other in virtual mode, and obtained favorable 3D display effects. The proposed method simplifies the light field data acquisition and image synthesis process, and supports handling both the virtual and the real‐world 3D scenes. We expect the proposed system to help the practical application of the InIm‐based LFD technology. [ABSTRACT FROM AUTHOR]

Paper chromatography is a simple and harmless experiment suitable for lower secondary education. Besides the training of subject‐specific contents, paper chromatography allows the application of modelling and simulation since the submicroscopic processes can be simplified in a way that they become understandable in lower secondary education. Here, the application of digital tools in addition to the experimental performance of paper chromatography in a compulsory STEM course in grade 6 is reported. Following a series of experiments, chromatography is at first simulated by a board game and then by computer simulations. Such simulation program allows the variation of the parameters in order to explore the model and to introduce the particle concept of matter and molecular interactions. The implementation with a graphical programming environment such as Scratch also allows the programming by pupils in this age group. In this way, it is possible to introduce modelling and simulation in an early stage as important contributions to scientific work in natural sciences. [ABSTRACT FROM AUTHOR]

The gap between computational chemistry and parametric device simulations limits the potentially immense impact of computer models on OLED R&D. We present a review on a bottom‐up multiscale modeling approach to bridge this gap and systematically eliminate performance bottlenecks by virtual design. In several case studies we demonstrate how microscopic simulations can support experimental R&D by identifying fundamental reasons for performance bottlenecks, and by deriving strategies for their elimination. [ABSTRACT FROM AUTHOR]

A passive, low‐cost, paper‐based intelligent reflecting surface (IRS) is designed to reflect a signal in a desired direction to overcome non‐line‐of‐sight scenarios in indoor environments. The IRS is fabricated using conductive silver ink printed on paper with a specific nanoparticle arrangement, yielding a cost‐effective paper‐based IRS that can easily be mass‐produced. Full‐wave numerical simulation results were consistent with measurement results, demonstrating the IRS's ability to reflect incident waves into a desired nonspecular direction based on the inkjet‐printed design and materials. [ABSTRACT FROM AUTHOR]

Signal‐to‐noise ratio and spatial resolution are quantitatively analysed in the context of in‐line (propagation based) X‐ray phase‐contrast imaging. It is known that free‐space propagation of a coherent X‐ray beam from the imaged object to the detector plane, followed by phase retrieval in accordance with Paganin's method, can increase the signal‐to‐noise in the resultant images without deteriorating the spatial resolution. This results in violation of the noise‐resolution uncertainty principle and demonstrates 'unreasonable' effectiveness of the method. On the other hand, when the process of free‐space propagation is performed in software, using the detected intensity distribution in the object plane, it cannot reproduce the same effectiveness, due to the amplification of photon shot noise. Here, it is shown that the performance of Paganin's method is determined by just two dimensionless parameters: the Fresnel number and the ratio of the real decrement to the imaginary part of the refractive index of the imaged object. The relevant theoretical analysis is performed first, followed by computer simulations and then by a brief test using experimental images collected at a synchrotron beamline. More extensive experimental tests will be presented in the second part of this paper. [ABSTRACT FROM AUTHOR]

The atrioventricular node (AVN) is a crucial component of the cardiac conduction system. Despite its pivotal role in regulating the transmission of electrical signals between atria and ventricles, a comprehensive understanding of the cellular electrophysiological mechanisms governing AVN function has remained elusive. This paper presents a detailed computational model of mouse AVN cell action potential (AP). Our model builds upon previous work and introduces several key refinements, including accurate representation of membrane currents and exchangers, calcium handling, cellular compartmentalization, dynamic update of intracellular ion concentrations, and calcium buffering. We recalibrated and validated the model against existing and unpublished experimental data. In control conditions, our model reproduces the AVN AP experimental features, (e.g. rate = 175 bpm, experimental range [121, 191] bpm). Notably, our study sheds light on the contribution of L‐type calcium currents, through both Cav1.2 and Cav1.3 channels, in AVN cells. The model replicates several experimental observations, including the cessation of firing upon block of Cav1.3 or INa,r current. If block induces a reduction in beating rate of 11%. In summary, this work presents a comprehensive computational model of mouse AVN cell AP, offering a valuable tool for investigating pacemaking mechanisms and simulating the impact of ionic current blockades. By integrating calcium handling and refining formulation of ionic currents, our model advances understanding of this critical component of the cardiac conduction system, providing a platform for future developments in cardiac electrophysiology. Key points: This paper introduces a comprehensive computational model of mouse atrioventricular node (AVN) cell action potentials (APs).Our model is based on the electrophysiological data from isolated mouse AVN cells and exhibits an action potential and calcium transient that closely match the experimental records.By simulating the effects of blocking specific ionic currents, the model effectively predicts the roles of L‐type Cav1.2 and Cav1.3 channels, T‐type calcium channels, sodium currents (TTX‐sensitive and TTX‐resistant), and the funny current (If) in AVN pacemaking.The study also emphasizes the significance of other ionic currents, including IKr, Ito, IKur, in regulating AP characteristics and cycle length in AVN cells.The model faithfully reproduces the rate dependence of action potentials under pacing, opening the possibility of use in impulse propagation models.The population‐of‐models approach showed the robustness of this new AP model in simulating a wide spectrum of cellular pacemaking in AVN. [ABSTRACT FROM AUTHOR]

This study investigates the effects of sea spray on extreme precipitation forecast in Beijing of China between 28 July and 2 August 2023 as a case test. In this case, fully coupled model increased upward moisture in the Bohai and Yellow Seas and increased accumulated rainfall by 21% in North China. For the extreme precipitation events with the 5‐day accumulated precipitation exceeding 500 mm, the atmosphere‐only model did not forecast the events; the coupled model without sea spray performed well with the 0.29 threat score (TS) and 88 mm root mean square error (RMSE); in the fully coupled model, the effects of sea spray increased atmospheric instability, which increased the precipitation around Beijing and yielded a more accurate forecast with the 0.37 TS and 65 mm RMSE. This paper suggests a scientific clue to improve numerical simulation for extreme rainfall events, however, more cases are still needed for statistical evaluation. Plain Language Summary: Although meteorological forecasting ability has been improved considerably during the past decades, precipitation during extreme events remains typically underestimated. Improving model accuracy for heavy rainfall events is, indeed, a ground challenge. In this study, we conducted three numerical experiments under different conditions to evaluate the effects of sea spray on extreme precipitation forecasts for the Beijing extreme rainfall event between 28 July and 2 August 2023. Our results indicated that for this 5‐day forecasting case, including sea spray in the simulations enhanced precipitation in North China by transporting more moisture from the Bohai and Yellow Seas upward into the atmosphere. The moister and warmer air caused by sea spray effects was transported to Beijing through northwestward wind and lifted by the local terrain, then caused a more unstable atmosphere and higher intensity of precipitation around Beijing. By using statistical indicators and setting different precipitation thresholds for this extreme rainfall case, we determined that in this case, the fully coupled model including sea spray yielded more accurate forecast. To statistically evaluate the effects of sea spray in extreme precipitation forecasts, more cases are still needed. Key Points: Fully coupled model led more upward moisture in the Bohai and Yellow Seas and increased 5‐day accumulated rainfall by 21% in North ChinaFully coupled model improved the forecasting threat score from 0 to 0.37 with the 5‐day accumulated precipitation exceeding 500 mmSea spray led to more unstable atmosphere for the Beijing extreme rainfall event, yielding a more accurate forecast [ABSTRACT FROM AUTHOR]

The semi‐underground double‐storey squat silo (SUDSSS) is a new type of silo with the advantages of preserving grain quality. In this paper, a numerical model of SUDSSS was constructed using solid elements. The proposed numerical model was validated by test results of an experimental underground silo, and the results demonstrated that: (1) Before and after backfilling, the radial and circumferential stress of the underground storey reached their maximum at 2/3 from the bottom and 2/3 from the ground surface, respectively; (2) As the height of grain storage increases, the silo wall stress in the overground storey increases. From the top of the underground storey up to 1/4 height of the overground storey, the stress of silo wall increases. (3) For the underground storey, the maximum stress occurs at 1/3 of the way from the apex of bottom cone. Practical applications: The semi‐underground double‐storey squat silo is a new grain storage device proposed by this paper, which consists of two layers. The lower layer is located in the ground and can utilize the shallow ground temperature to realize the green and low‐temperature storage of grain, the upper layer is conducive to the turnover of grain, which can ensure the quality of grain storage. The new silo has the advantages of saving land, energy saving and carbon reduction. Based on the silo, this paper investigates the stress–strain properties of the silo before and after soil backfilling during the construction stage, and obtains the change pattern of the static mechanical properties of the silo. This paper analyses the mechanical properties of semi‐underground double‐storey squat silo under different storage conditions at the grain storage stage, and studies the change patterns of the mechanical properties of the silo body under different storage heights. [ABSTRACT FROM AUTHOR]

The paper presents a study of the upstream influence of wind farms on the wind speed, which is called blockage effect. A Reynolds Averaged Navier–Stokes (RANS) numerical model using an actuator disc method was devised and validated using the SCADA data from a Horns Rev 1 wind farm. The maximum difference between the average power in the first row for SCADA and the numerical model was 7.8%. The model was used to determine the impact of blockage effect on the wind farm parameters and the extent to which the wind speed and the power generation were reduced. A reference wind farm was defined, with a modified size, spacing, turbine height, and diameter that were used for comparison with other wind farm configurations. The results of the investigation of the wind farm parameter effects on the upstream wind speed reduction are presented in the paper. It has been established that increasing the turbine spacing from 5D to 6.7D reduces the power loss due to blockage by two. Blockage losses are almost eliminated when the spacing is increased two times. Similarly, the wind turbine thrust coefficient (CT) has a large impact on blockage, which is more pronounced, when CT is higher. In fact, the velocity deficit due to blockage is proportional to CT. The turbine tower height has small impact on blockage effect—the power reduction was changed by 0.3% due to blockage for the investigated range. The number of turbines in a row (with a constant number of turbines in a row) does not affect blockage significantly. [ABSTRACT FROM AUTHOR]

This paper describes the main features and goals of the speculative work in modern sciences that has greatly accelerated since World War II due to the exponential increase in computing power and newly available theoretical and conceptual tools. It points to the long historical strand of speculative philosophical work in symbiosis with the sciences, suggests the reasons for its unexpected neglect in contemporary professional philosophy of science, why it should be a major approach, and why such pursuit is not inevitable. Finally, the paper outlines potential topics, fields, and tools for such collaborative work and argues it is likelier to be more fruitful today than at any point in the past hundred years. [ABSTRACT FROM AUTHOR]

This paper investigates the model performance of an industrial box used to remove ammonia from the air using a doped activated carbon. To this end, process models are developed and experimental measurements are carried out. The models are based on momentum and mass balance equations along with thermodynamic, hydrodynamic and adsorption kinetic relations. The measurements consist of pressure drops in the air purification box and breakthrough curves of ammonia on activated carbon. The models are implemented and solved using COMSOL Multiphysics®. Adsorption is investigated by means of a Fickian multi‐scale model, which demonstrated to efficiently predict the experimental data. The optimal values of the most estimable unknown parameters involved in each model, as well as their confidence intervals are determined from experimental measurements. The performance of the industrial air purification model is rigorously assessed using statistical criteria, including mean‐square error (RMSE = 0.0013) and Pearson correlation coefficient (r = 0.999). [ABSTRACT FROM AUTHOR]

In the era of document‐centric systems engineering, large organizations developing complex systems had practical methods of associating drawings, specifications, requirements and other information with each other. Mostly these evolved methods involved part numbers and drawing numbers, although sometimes the methods included mundane techniques such as storing drawings in specific drawers in specific filing cabinets. These manual methods were very labor intensive, did not handle changes gracefully, and were somewhat error prone. As computer software and modeling tools began to displace paper drawings and filing cabinets, a "connect and forget" style of linking evolved. We can see this sort of thinking in the relationships in UML and SysML, but also in other places such as the use of Universally unique identifiers (UUIDs) in the XMI file format underlying UML/SysML, the relationships in DOORS and related requirements tools, as well as the original architecture of OSLC which depended on URIs embedded in design artifacts to establish relationships. While these "click to connect" features provided increased convenience compared to the previous manual numbering approaches, these "hard‐coded" links have introduced a new set of problems. The root of most of the new problems comes in the difficulty of managing this sort of extremely large set of direct links as configuration items in their own right. In a larger system, this sort of link set quickly grows to thousands or even millions of links. Managing change, modularity, variants, subsystem reuse, and so on all become very difficult in the presence of such a large, unplanned, and uncontrolled link set. In this paper, we will review the different approaches to creating and managing such sets of links and provide a concise best practices recommendation for the configuration management of such sets of links. [ABSTRACT FROM AUTHOR]

This paper proposes a robust distributed observer for uncertain systems where some unknown, unstructured, and bounded uncertainties exist in system matrices. In distributed observer, each node includes an observer which directly estimates a part of the system states by its limited measurements and further, the estimation of other states indirectly obtains via exchanging information with neighbouring nodes. It is shown that whole states convergence achieves if the LTI system is observable as well as the network graph is strongly connected. Also, in the proposed distributed observer, by applying a new term in dynamic equation, the robust performance is achieved in dealing with uncertainties in system matrices. The observer gains synthesis is then formulated in terms of linear matrix inequalities. Finally, the simulation results are presented to illustrate the effectiveness of the proposed distributed observer to handle system uncertainties. [ABSTRACT FROM AUTHOR]

This paper explores the finite‐time stability of reaction–diffusion genetic regulatory networks with time‐varying mixed delays. These delays encompass discrete delays and distributed delays. Unlike many existing studies, this paper assumes that both types of delays are bounded and continuous, without requiring differentiability. Additionally, the analysis combines the inequality approach and comparison method, while neither a Lyapunov–Krasovskii functional is constructed nor the finite‐time stability theorem is involved. The finite‐time stability of the addressed networks is then ensured by several suitable algebraic criteria. Some extended results are deduced for networks without considering reaction–diffusion and distributed delays effects as special cases. Finally, the validness of the derived results is proved by numerical simulations. [ABSTRACT FROM AUTHOR]

To explore the independent influence of the main factors affecting heating on the radiant floor heating system, CFD was used to simulate the simplified multi‐storey multi‐family building model under different working conditions, and focusing on the calculation and comparative analysis of these four factors (heating supply, the location of room, outdoor temperature and the neighboring heating situation). The results showed that heating supply is the most important factor affecting indoor temperature, and the change of heating supply has the most obvious effect on the change of indoor temperature in the middle of the bottom layer, and the least effect on the edge of the top layer, which is a 1.6–1.7 times relationship. The influence of outdoor temperature on indoor temperature mainly depends on the area proportion of external envelope structure, and the changing rates of the indoor temperature of the edge of the top layer, the middle of the top layer, the edge of the bottom layer, the middle of the bottom layer with the outdoor temperature are 0.94, 0.93, 0.88, and 0.86. The influence of the neighboring heating situation on indoor temperature mainly depends on the surface area proportion of inner envelope structure, and the proportion of heat gain (dissipation) of each envelope to the total heat supply is basically the same, the heat dispersed through the north wall, south wall, east wall and west wall of the room at the middle of the bottom layer account for about 34%, 37%, 9%, and 9% respectively. [ABSTRACT FROM AUTHOR]

Based on a single‐phase cascaded H‐bridge (CHB) multilevel converter, this paper investigates a control strategy combining power estimation and natural frame control (NFC) with the omission of grid voltage sensors. Besides, this control method, without phase‐locked loop (PLL), can meet the continuous operation of the system and also eliminates grid voltage feedforward. First, natural frame control is introduced to derive the implementation process of control strategy without PLL, and the calculation formula of AC reference currents is given. Furthermore, the separate control of active and reactive currents is achieved. Second, the principle of proposed control algorithm is presented, and the sinusoidal voltage unit vector for synchronization can be accurately estimated. Next, considering the errors, the article corrects the method through parameter compensation. In addition, the balanced control method stabilized the DC side voltage of the converter. Finally, the effectiveness of this method is verified by computer simulation and experimental prototype. [ABSTRACT FROM AUTHOR]

This paper proposes a novel primary frequency regulation (PFR) scheme for multi‐infeed high voltage direct current (HVDC) (MIDC) system. First, a dynamic model for frequency response in the MIDC system is carried out to involve line‐commutated‐coveter (LCC)‐HVDCs in frequency regulation. Then, a disturbance observer (DO) is proposed to estimate both the power imbalance and the full order states of the system. By combining a Kalman filter, this DO gets an accurate estimation quickly with local frequency measurement. On the basis of the estimated disturbance and state variables, feedforward control schemes can be concluded to fully utilize the fast adjustability of LCC‐HVDCs. In this paper, a model predictive control based scheme is designed to coordinate LCC‐HVDCs under constraints of HVDC capacity and frequency boundaries. As a result, the optimal power‐sharing property of LCC‐HVDCs is achieved to enhance the PFR dynamic performance of the AC main system. Further, the stability of the proposed method is analysed using the Lyapunov method. Finally, numerical simulations are concluded to verify the effectiveness and the merits of the proposed method, by comparing it to typical droop controls. [ABSTRACT FROM AUTHOR]

This paper focuses on a class of exponential stability control problem for the stochastic neural networks (SNNs) with time‐varying delays and Markov jump (TVDMJ). As a prerequisite to the main theorem, the existence and uniqueness of the solution for the main system are proved via contraction map principle. For the stability control of the system, we design a controller Ct,xtδδ,m(t)$$ C\left(t,x\left(\left[\frac{t}{\delta}\right]\delta \right),m(t)\right) $$ which can be adjusted the parameters δ$$ \delta $$ to make the system stabilization. We use this controller to actively control the stability behavior of the system, rather than the papers by setting the appropriate parameters to make the system achieve a stable state. Based on the intermittent control, we design a novel trajectory similarity process control and obtain exponential stability results, which are less conservative than the existing theoretical results. Two examples based on some numerical calculation and simulation diagrams are presented to validate the effectiveness for the utilized techniques. [ABSTRACT FROM AUTHOR]

Background: The potential of learning analytics dashboards in virtual reality simulation‐based training environments to influence occupational self‐efficacy via self‐reflection phase processes in the Chemical industry is still not fully understood. Learning analytics dashboards provide feedback on learner performance and offer points of comparison (i.e., comparison with one's own past performance or comparison with peer performance) to help learners make sense of their feedback. Objectives: We present a theoretical framework for describing learning analytics reference frames and investigate the impact of feedback delivered through dashboards with different reference frames on occupational self‐efficacy, while controlling for workplace self‐reflection. Methods: This experimental study engaged 42 chemical operator employees, aged between 18 and 55 years, each with at least one year of experience. We utilised a two‐group design to ask two research question each with three competing hypotheses related to changes in occupational self‐efficacy, employing Bayesian informative hypothesis evaluation. Results and Conclusions: Results for the primary research question suggest that dashboards with progress reference frames do not elicit greater change to self‐efficacy than those with social reference frames, however, they may elicit equal change. Furthermore, dashboards with social reference frames may elicit greater change to self‐efficacy than those with progress reference frames. Exploratory results found that dashboards with progress reference frames may elicit greater positive directional change than those with social reference frames and that they may elicit equal directional change. These findings contribute to the understanding of self‐efficacy beliefs within the Chemical industry, with potential impacts on skill development. The research may inform the design of targeted interventions and training programs to influence self‐efficacy. From a practical perspective, this research suggests that careful consideration is needed when choosing reference frames in learning analytics dashboards due to their potential consequences on the formation of learner self‐efficacy. Lay Description: What is already known about this topic?: Learning analytics dashboards often aim to stimulate self‐regulated learning by providing feedback.Feedback plays a crucial role in simulation‐based learning and learning analytics dashboards can be a valuable tool to deliver feedback and facilitate the learning process by providing learners with insights into their performance and progress.Previous research has highlighted the importance of reference frames as critical design features of learning analytics dashboards, as they assist learners in making sense of learning analytics feedback.Self‐efficacy is a powerful determine factor of workplace performance and is influenced by mastery experiences and social modelling information. What the paper adds?: A theoretical framework describes the mediating role self‐reflection phase processes of the self‐regulated learning cycle plays in the formation of occupational self‐efficacy.This paper introduces the concept of three learning analytics reference frame components which include the performance outcome component, point of comparison component and score delta component.The paper indicates that learning analytics dashboards designed with a progress reference frame does not elicit greater change to occupational self‐efficacy than the social reference frame.Exploratory results suggest dashboards with progress reference frames might produce greater positive directional change compared to social reference frames or elicit equal change. Implications for practice?: Learning analytics system designers who use reference frames to help learners make sense of their feedback should carefully consider which reference frames they use as these decisions likely have consequences on the formation of learner self‐efficacy beliefs.For LAD designers and stakeholders, recognising the absolute change and directional shift in self‐efficacy is crucial, as LAD designs significantly influence these dynamics and guide the tailoring of effective tools.In industries like the chemical sector, where overconfidence can result in severe consequences, understanding the nuance of self‐efficacy changes is especially pertinent. [ABSTRACT FROM AUTHOR]

In this paper, the concept of crossed foldable display module is proposed as follows: there are two foldable axes, and the two foldable axes intersect vertically. In order to realize the crossed foldable display, it needs to be designed in terms of modules, hinges and so on, especially the module support layer in the intersection area. In this paper, the steps of structural design, numerical simulation and sample verification are used to obtain two kinds of support layers suitable for crossed foldable modules, which can be folded hundreds of thousands of times without failure in the whole module test verification, providing a new form for flexible display. [ABSTRACT FROM AUTHOR]

Four‐Wave Mixing (FWM) is one of the non‐linear phenomena affecting long‐reach communication systems and high bandwidth. Research communities use simulation tools for parameter optimization. Unfortunately, such a simulation is time‐consuming and requires more time as the number of channels increases. This paper proposes two fast implementations of Dense Wavelength Division Multiplexing (DWDM) system, limited by FWM and the intrinsic Amplified Spontaneous Emission (ASE) noise of optical amplifiers employed in each segment. Additionally, this work compares the efficiency and speed improvement of the proposed parallelization model versus an earlier sequential model. We present the computational complexity analysis of sequential and parallel models. The paper considers two different parallel implementations: a multicore processor using Open MultiProcessing (OpenMP) and Compute Unified Device Architecture (CUDA), which is based on the use of a Graphics Processing Unit (GPU). Results show that parallelism using CUDA improves by up to 70 times the simulation performance compared to the sequential model. Parallelism with CUDA is up to 15 times compared to OpenMP using 12 logical processors. It is possible to simulate an increased number of channels within our parallel execution, which was impractical in the sequential simulation. [ABSTRACT FROM AUTHOR]

This work addresses the ongoing challenge of optimizing sand control screens, attributed to a limited understanding of screen blocking. A novel one‐way computational fluid dynamics and discrete element method (CFD–DEM) coupling technique is presented to analyze the structural parameters of unconsolidated prepacked gravel screens (PPGS). CFD–DEM involves systematically investigating the width of the punched slot on the outer protective screen, the size of the gravel, and the efficiency of gravel packing to improve the antiblocking capability of unconsolidated PPGS. Results from numerical simulations reveal that under conditions of effective sand control, the amount of sand entering the gravel layer to the bridge (referred to as the sand pass rate) is positively correlated with the antilocking ability (referred to as oil productivity index) for unconsolidated PPGS. The efficiency of gravel packing has the most substantial effect on the antilocking performance of unconsolidated PPGS. The data suggest that appropriately reducing the efficiency of gravel packing can enhance the antilocking capability of unconsolidated PPGS. To design an unconsolidated PPGS with enhanced antilocking capability, the efficiency of gravel packing be determined first. Then, the gravel size is designed based on this efficiency, and the width relative to the gravel size is decided. This contemporary design principle diverges considerably from previous design principles for gravel‐packed sand control screens. Supporting validation experiments agree with simulation outcomes, suggesting the established one‐way CFD–DEM coupling method in this paper is suitable for analyzing the plugging mechanism of unconsolidated PPGS. Thus, the CFD–DEM coupling method improves the design of such screens for improved antiblocking performance. [ABSTRACT FROM AUTHOR]

The first Joint Workshop on Representation Uncertainty in the Earth Sciences was held in March 2021. This brought together the Earth observation, data assimilation and forecast verification and post‐processing communities, alongside metrologists to discuss the definition and quantification of representation uncertainty within the Earth sciences. The aim of the workshop was to facilitate cross‐disciplinary discussion, establishing where existing methodologies could be shared and to foster future collaboration. A key outcome of the workshop was a working definition of representation uncertainty applicable across all the Earth science communities, which is presented in this white paper. The cross‐disciplinary discussions at the workshop highlighted the need for scientists to work with metrologists to establish a common vocabulary for uncertainties, accessible to Earth science applications. Further recommendations included regular workshops to discuss progress in defining and quantifying representation uncertainty and awareness of cross‐disciplinary funding opportunities to further address representation uncertainty issues. Plain Language Summary: This paper describes a workshop which brought together experts from different Earth science disciplines to discuss and attempt to define the term "representation uncertainty". We make observations of the Earth using satellites, ground based instruments (such as weather stations), air and sea‐borne sensors. These observations are used in their own right, and also by computer models to generate weather forecasts. The observations themselves are imperfect and we quantify these imperfections using the term "uncertainty". In this paper we discuss the uncertainty that occurs when we compare two different sets of observations, two different models, observations and models, or where there are differences in underlying assumptions. As well as the uncertainties inherent in models and observations, there is also an uncertainty due to the fact that the two things being compared are not representing a phenomenon in exactly the same way. For example, a satellite observation may represent an average value over a few hundred square meters, while an instrument on the surface measures only at a single point (typically one‐square‐meter or less), and the model represents an area of several square kilometres. Understanding those differences is essential to be able to properly combine different sets of observations, and observations with models. Key Points: Representation uncertainty can be defined as occurring at a comparison interface between two quantitiesA common definition of representation uncertainty can be applied across the Earth Science communityCollaboration between scientists and metrologists is recommended to define an accessible and relevant vocabulary for uncertainty analysis [ABSTRACT FROM AUTHOR]

For the robot control problems, the input constraint is an issue that must be carefully considered. Considering the control inputs of the robots in the multi‐robot system are constrained by different saturations in reality, we address the cooperative circumnavigation control problem of multiple unicycle‐type robots with non‐identical and unknown input constraints in this paper. A distributed control law is designed to drive the robots constrained by different and unknown input saturations to achieve the cooperative circumnavigation around a moving target. The algorithm proposed in this paper largely reduces the requirement for the maneuverability of the robots to achieve the cooperative circumnavigation. As long as the robots owns the basic maneuverability of circumnavigating around the target, it is proved rigorously that the proposed control algorithm can achieve the desired cooperation circumnavigation of the multi‐robot system. The effectiveness of the proposed method is validated by a numerical simulation. [ABSTRACT FROM AUTHOR]

The paper describes how the calculation of diffuse scattering from atomistic model crystals has developed over the last approximately 50 years. Not only has the quality of observed diffuse X‐ray scattering data improved immensely with the advent of electronic area detectors and synchrotron radiation but the enormous increase in computer power has enabled patterns, of comparable quality to the observations, to be calculated from a Monte Carlo model. [ABSTRACT FROM AUTHOR]

A three‐bladed, dual‐axis teetering hub (3T) has been developed and compared to a three‐bladed rigid hub (3R) using computer modeling. Both hubs were fitted to a hypothetical 5‐MW offshore wind turbine mounted on an offshore floating platform. Cyclic analysis showed the 3T hub significantly reduced the impact of wind shear on the blades and virtually eliminated the impact of both turbulence and wind shear on the main shaft bearing and yaw bearing. Lifetime fatigue studies for the two hubs were performed using a rainflow‐counting program at various levels of turbulence and wind shear. Studies showed the significant reductions in cyclic variation provided by the 3T hub resulted in significant reductions in lifetime fatigue in comparison to the 3R hub. Simulations with the 3T hub showed an increase in turbulence caused a very small increase in blade fatigue but no increase in fatigue for the main shaft bearing and yaw bearing. In contrast, fatigue studies with the 3R hub showed an increase in turbulence caused significant damage to the blades and a combined increase in turbulence and wind shear caused extremely significant damage to the blades. This paper introduces a recently patented hub design that is superior to the ball‐and‐socket design described in a prior paper by this author. [ABSTRACT FROM AUTHOR]

By combining the filter circuit and boost circuit, the filter‐integrated three‐switch boost inverter (TSBI) is proposed in this paper. Different from the traditional boost inverter, TSBI achieves the boost function at the AC side, so the voltage stress on the switches is small. Through modelling and analysis, the boosting characteristics and filtering characteristics of the system are obtained. The proposed topology can significantly suppress the resonance spike and does not need to add additional filtering equipment, which can reduce the volume of equipment and system loss. In order to clearly illustrate the advantages and disadvantages of the proposed topology, this paper makes a detailed comparison with other types of inverters. Finally, the feasibility of the system is verified by experiment and simulation. [ABSTRACT FROM AUTHOR]

The first true common volume observations of the PMSE source region with 4 radars are presented in this paper. Radar frequencies of 8, 56, 224, and 930 MHz are used in this study. Three days of experimental observations at EISCAT are presented. Numerical simulations of mesospheric dusty/ice plasma associated with the observed radar frequencies are presented. The effect of neutral air turbulence on the generation and strength of plasma density perturbations associated with PMSE using four radar frequencies and in the presence of various dust parameters is investigated. Using the model it is shown that the well‐known neutral air turbulence in the presence of heavy dust particles and neutral air turbulence combined with dust density (dusty turbulence) can largely explain the observed radar cross‐section at four radar frequencies. The effect of neutral air turbulence amplitude along with dust charging and diffusion in the presence of various dust parameters is investigated using the computational model. Specifically, the response of diffusion to charging time scales, plasma density fluctuation amplitude and background dusty plasma parameters are discussed. Several key parameters in the dusty plasma responsible for the PMSE observations are determined. Qualitative comparison of radar echo strength at 4 frequencies with numerical results is provided. Unlike the previous studies that required large dust particles of 20 nm for PMSE formation, the present work demonstrates the possibility of small dust particles to explain the experimental observations. Key Points: The first simultaneous four radar frequency observation of the PMSE is presentedThe computational results and observations validate the fossil theory proposed to 14 produce the PMSEThe effect of initial turbulence amplitude along with dust charging and diffusion 16 in the presence of various dust parameters is investigated for the first time [ABSTRACT FROM AUTHOR]

Ants, an ecologically successful and numerically dominant group of animals, play key ecological roles as soil engineers, predators, nutrient recyclers, and regulators of plant growth and reproduction in most terrestrial ecosystems. Further, ants are widely used as bioindicators of the ecological impact of land use. We gathered information of ant species in the Atlantic Forest of South America. The ATLANTIC ANTS data set, which is part of the ATLANTIC SERIES data papers, is a compilation of ant records from collections (18,713 records), unpublished data (29,651 records), and published sources (106,910 records; 1,059 references), including papers, theses, dissertations, and book chapters published from 1886 to 2020. In total, the data set contains 153,818 ant records from 7,636 study locations in the Atlantic Forest, representing 10 subfamilies, 99 genera, 1,114 ant species identified with updated taxonomic certainty, and 2,235 morphospecies codes. Our data set reflects the heterogeneity in ant records, which include ants sampled at the beginning of the taxonomic history of myrmecology (the 19th and 20th centuries) and more recent ant surveys designed to address specific questions in ecology and biology. The data set can be used by researchers to develop strategies to deal with different macroecological and region‐wide questions, focusing on assemblages, species occurrences, and distribution patterns. Furthermore, the data can be used to assess the consequences of changes in land use in the Atlantic Forest on different ecological processes. No copyright restrictions apply to the use of this data set, but we request that authors cite this data paper when using these data in publications or teaching events. [ABSTRACT FROM AUTHOR]

This paper addresses the development of a set of novel autonomous control laws for the navigation of multiple mini or micro quadrotors in a workspace populated with cylindrical obstacles. To the authors' knowledge, this is the first time that such a set of control inputs for the autonomous control of multiple quadrotors and avoidance of cylindrical obstacles is being derived from a single Lyapunov function. The avoidance of the cylindrical obstacles is achieved via a Minimum Distance Technique that allows a quadrotor to avoid the closest point on the curved surface of a cylinder at every unit time. In addition, the novel controllers ensure a near‐to‐horizontal orientation of a quadrotor at every unit time and the hovering motion exhibited by the quadrotor in a neighborhood of its target. The hovering capability has been solved completely in this paper by solving the underactuatedness of the quadrotor which allows for the design of the maximum translational velocities needed for vertical take‐off and landing, and hovering. This is important in applications where payloads are sensitive to acrobatic orientations. Computer simulations that mimic real‐life scenarios using cylindrical towers as obstacles in a city‐like environment illustrates the effectiveness of the controllers. [ABSTRACT FROM AUTHOR]

The problem of robust exponential stabilization for T‐S fuzzy stochastic dynamical networks (T‐S FSDNs) based on the state‐dependent impulsive controller is investigated in the paper. Using B‐equivalence approach, some sufficient conditions are provided such that every solution of considered systems intersects each impulsive surface exactly once. Then, combining with the inequality technique and comparison principle, some meaningful sufficient criteria are obtained to ensure the mean square stability of T‐S fuzzy stochastic dynamical networks. Compared to related results, the results obtained in the paper are low conservatism and easy to verify. Finally, two numerical simulations based on Rö$$ \ddot{o} $$ssler's system and Lorenz system show the effectiveness of the obtained theoretical results. [ABSTRACT FROM AUTHOR]

Most of the Italian infrastructures have been built since the mid‐twentieth century. Prestressed concrete (PC) has been widely used, especially for bridges and viaducts. These structures have proved effective over time, but their performance could be affected by degradation phenomena (i.e., corrosion of the tendons and residual prestressing) or construction defects (i.e., grouting of the ducts), which need to be accurately modeled. This paper focuses on the flexural response of two reduced‐scale, posttensioned, PC bridge girders, prestressed with two different jacking forces and tested under four‐point bending configuration. Four multidimensional numerical models were developed to simulate the experimental behaviors of the selected specimens, using two alternative computational strategies, namely, the finite element method (FEM) and applied element method (AEM). Three FEM modeling were considered, ranging from one‐dimensional lumped‐plasticity models to two‐dimensional and three‐dimensional (3D) spread‐plasticity models. Besides, 3D AEM models were developed into another software package. The accuracy and the computational costs of the two numerical strategies are discussed in this paper. Also, the main features of each numerical modeling technique are addressed, including comparisons between numerical and experimental global response data as well as the statistical characterization of the model error. Based on these different features, the authors also suggest the most suitable numerical strategy for future studies on PC girders. [ABSTRACT FROM AUTHOR]

This paper addresses the problem of distributed finite‐time (FT) event‐triggered consensus of multi‐agent systems (MASs) under fixed and switching topologies. To conserve the limited communication resources, a new distributed event‐triggered control protocol is proposed, in which the agents exchange information via discontinuous communication among the follower agents. Then, to solve the FT consensus problem, norm‐normalized sign functions are employed, and sufficient Lyapunov conditions are provided. On this basis, the MASs proves capable of reaching consensus within finite time under fixed and switching topologies. Finally, the effectiveness of the developed algorithm is verified via numerical simulation. [ABSTRACT FROM AUTHOR]

The false data injection (FDI) attack detection problem in cyber‐physical systems (CPSs) is investigated in this paper. A novel attack detection algorithm is proposed based on the ellipsoidal set‐membership approach. In comparison to the existing FDI attack detection methods, the developed attack detection approach in this paper neither requires predefined thresholds nor specific statistical characteristics of the attacks. In order to guarantee that the estimation ellipsoid contains normal states despite the unknown but bounded (UBB) process and measurement noises, the one‐step ellipsoidal set‐membership estimation method is put forward. In addition, a convex optimization algorithm is introduced to calculate the gain matrix of the observer recursively. Moreover, with the help of the state estimation ellipsoid, the residual ellipsoid can be obtained for attack detection. Whether a detector can detect the FDI attack depends on the relationship between the residual value and residual ellipsoidal set. Finally, the effectiveness of the proposed method is demonstrated by a numerical simulation example. [ABSTRACT FROM AUTHOR]

Many natural and economic systems are managed to deliver the highest benefits to society but are subject to regime shifts. We specifically consider the variability of the size of the system itself as a key driver of a regime shift. We address the question of how the optimal management of these systems should vary with its size. Put simply, certain management options might work when the system is of a given size, while others might be preferred when the system has grown or shrunk. In this paper, we develop a model that allows us to analyse the effect of the size of the system on its optimal management. We apply this model to a case of water pollution in a reservoir/lake that varies in size over time: sometimes the lake is deep and sometimes it is shallow. Numerical simulations were conducted to compare optimal management of the reservoir with and without explicitly modelling its size variation. The findings show that the overall social costs of optimally managing pollution are significantly smaller when the variability in size is taken into account. This is due to differences in the timing and magnitude of the optimal control. The key implication is that the variability of the size of a system should be explicitly considered in this type of management problems. [ABSTRACT FROM AUTHOR]

In this paper, we investigate an assist control for a system in which a human and a robot cooperate to transport an object toward a designated position and angle. We consider a situation where the force due to the human to the object cannot be measured directly. In order to tackle this situation, an assist control with a nonlinear disturbance observer is proposed. By using the observer, we estimate the control input due to the human from position and angle of the object. Moreover, we design the control input by the robot to assist the human input based on the estimates by the disturbance observer. The effectiveness of the proposed method is discussed by numerical simulations for the minimum jerk model. [ABSTRACT FROM AUTHOR]

This paper proposes a novel damage index for railway bridges based on synchronous strain and displacement data collected at the passage of trains. The approach identifies a transformation operator that converts strains into displacements in a data‐driven fashion without prior structural knowledge and with no parameter selection. The displacement prediction error is proposed as a robust damage index, insensitive to the vehicle loads and temperature effects. Numerical simulations and data generated through the calibrated finite element model of a steel truss bridge showcase the effectiveness of the proposed approach. [ABSTRACT FROM AUTHOR]

This paper considers a two‐species chemotaxis system with chemical signaling loop and Lotka–Volterra competition kinetics under the homogeneous Newman boundary condition in smooth bounded domains. The global existence and boundedness of solutions for the parabolic–elliptic/parabolic–parabolic system are established. In the strong competition case, the global stability of the semitrivial constant steady state is obtained under certain parameter conditions. Linear analyzes and numerical simulations demonstrate that chemical signaling loop can significantly impact population dynamics, and admit the coexistence in the exclusion competitive case, including nonconstant steady states, chaos, and spatially inhomogeneous time‐periodic types. [ABSTRACT FROM AUTHOR]

This historical review addresses the issues of the evaluation and testing of hydrological models, with a focus on rainfall–runoff models. After a discussion of the general philosophies of hydrological modeling, nine different philosophies of model evaluation are considered, focusing on the period of modeling on digital computers since the 1960s. In addition, some discursions to discuss the definitions of calibration and validation, how much data is needed for model calibration, equifinality and uncertainty, probabilities and possibilities, the evaluation of model ensembles, and model benchmarking. The paper finishes with a final discursion on the philosophical problem of induction.This article is categorized under: Science of Water > Methods Science of Water > Hydrological Processes [ABSTRACT FROM AUTHOR]

ABSTRACT Measurement errors are ubiquitous in all experimental sciences. Depending on the particular experimental platform used to acquire data, different types of errors are introduced, amounting to an admixture of additive and multiplicative error components that can be uncorrelated or correlated. In this paper, we investigate the effect of different types of experimental error on the recovery of the subspace with principal component analysis (PCA) using numerical simulations. Specifically, we assessed how different error characteristics (variance, correlation, and correlation structure), loading structures, and data distributions influence the accuracy to estimate an error‐free (true) subspace from sampled data with PCA. Quality was assessed in terms of the mean squared reconstruction error and the congruence to the error‐free loadings, using the pseudorank and adjusting for rotational ambiguity. Analysis of variance reveals that the error variance, error correlation structure, and their interaction with the loading structure are the factors mostly affecting quality of loading estimation from sampled data. We advocate for the need to characterize and assess the nature of measurement error and the need to adapt formulations of PCA that can explicitly take into account error structures in the model fitting. [ABSTRACT FROM AUTHOR]

In this paper, we consider an estimation problem of sideslip angle and cornering stiffness of a vehicle from measurements of yaw rate, lateral acceleration and steering angle. Firstly, a vehicle dynamical model is expressed as a linear parameter‐varying system with cornering stiffness as uncertain parameters. Then, we show a method to estimate the parameters and the state based on moving horizon estimation. We provide a simple algorithm to solve the estimation problem. The effectiveness of the estimation method is evaluated through numerical simulations. © 2024 Institute of Electrical Engineers of Japan and Wiley Periodicals LLC. [ABSTRACT FROM AUTHOR]

Summary: In this paper, we investigate the effectiveness of incremental relaying (IR)‐based underlay cognitive nonorthogonal multiple access (CNOMA) system with maximal ratio combining (MRC). Considering imperfect successive interference cancelation (i‐SIC), we derive analytical expressions for the outage probabilities experienced by the secondary users (SUs) and the system outage probability of the IR‐CNOMA system. We also derive the analytical expression for the outage probability of far SUs by considering IR‐CNOMA system with MRC. The maximum transmit power constraint of the secondary nodes and the interference threshold constraint of the primary receiver are considered in the analysis. We also evaluate the system throughput of IR‐CNOMA network. We also derive outage and throughput expression for the traditional cooperative relaying‐based CNOMA system (CR‐CNOMA) for the purpose of comparison. We derive analytical expression for the asymptotic outage probability and the asymptotic system outage probabilities of the SUs of IR‐CNOMA system. Further, we derive expressions for the optimal power allocation (OPA) factor at the secondary source that minimizes the asymptotic system outage probability of the IR‐CNOMA system. Through numerical and simulation investigations, we demonstrate that the system outage probability significantly lowers when the OPA factor is selected based on the criteria outlined in this work. It can be observed from the results that the IR‐CNOMA system outperforms the conventional CR‐CNOMA system in terms of outage probabilities and throughput. The outage probability is further reduced when IR‐CNOMA system with MRC is considered for the far SUs. [ABSTRACT FROM AUTHOR]

In this paper, we consider a singular diffusive predator–prey model with Beddington–DeAngelis functional response, employing geometric singular perturbation theory and Bendixson's criteria. Our investigation revolves around transforming the reaction–diffusion equation into a multi‐scale four‐dimensional slow–fast system with two different orders of small parameters. Through once singular perturbation analysis, our focus shifts towards exploring the existence of heteroclinic orbits in a three‐dimensional system. We analyze these dynamics through the perspective of the Fisher–KPP equation in two limit cases. In the first case, only the normal to the two‐dimensional slow manifold is unstable. This allows for the deduction of existence of heteroclinic orbits in the three‐dimensional system through investigating the dynamics on the two‐dimensional slow manifold. Consequently, we obtain both monotonic traveling fronts and non‐monotonic fronts with oscillatory tails. In the second case, the normal to the one‐dimensional slow manifold exhibits both stable and unstable directions, then it is impossible to restrict the dynamics of the three‐dimensional system entirely to the slow manifold. Instead, we integrate the slow orbits of the reduced system with the fast orbits of the layer system to construct a singular heteroclinic orbit. According to Fenichel's theorem, we discover the existence of exact heteroclinic orbits of three‐dimensional system and derive the monotonic traveling fronts under weaker parameter conditions. Additionally, we also discuss the nonexistence of traveling fronts. Finally, we demonstrate our theoretical results with numerical simulations. [ABSTRACT FROM AUTHOR]

In this paper, we propose and study a discretized one‐predator two‐prey system along with prey refuge and Michaelis–Menten‐type prey harvesting. The interaction among the species is considered as Holling type III functional response. Firstly, existence and local stability of all the fixed points are derived under certain parametric conditions. Furthermore, a special consideration is made to global asymptotic stability of the interior fixed point. Then, we have shown that the system undergoes different types of bifurcations including transcritical bifurcation, flip bifurcation, and Neimark–Sacker bifurcation by using center manifold theorem, bifurcation theory, and normal form method. Also, Feigenbaum's constant of the system is calculated. It is observed that both harvesting and refuge have a stabilizing effect on the system, and the stabilizing effect of harvesting dominates the stabilizing effect of refuge. Of most interest is the finding of coexisting attractors and multistability. In particular, optimal harvesting policy has been obtained by extension of Pontryagin's maximum principle to discrete system. Finally, some intriguing numerical simulations are provided to verify our analytic findings and rich dynamics of the three species system. [ABSTRACT FROM AUTHOR]

In this work we base our analysis on a seminal paper by Paul Germain (1973) in which the principle of virtual work is used to found microstructured continuum mechanics. Recently, it was shown that a particular considered microstructured continuum can be regarded as a second gradient continuum of the kind studied by Germain. To prove how these theoretical ideas can be useful in applications, we present the paradigmatic case of pantographic metamaterials, in which the deformation energy may depend only on placement second gradient being independent on placement first gradient. In this case, the numerical simulations become more efficient by introducing the Lagrange multipliers which are dual in work of the introduced kinematical constraint, so proving that the viewpoint about stress presented originally by Lagrange is the most fruitful one. [ABSTRACT FROM AUTHOR]

Summary: It is well known that hardware impairments (HWIs) can worthy reduce the wireless system performance at high carrier frequencies by showing random effects. Most current researches for 5 GB systems assume that transmitters and receivers (transceivers) are perfectly equipped. But wireless transceivers (TxRx) are affected by HWIs in practice. Considering the previous studies in the literature, it is reported that HWIs have devastating effects on the performance of OFDM and OFDM‐index modulation (IM) systems with fading channels. In this paper, in‐phase and quadrature phase imbalance (IQI), which is the one of most HWIs between transmitter and receiver in wireless communication systems, is examined on OFDM‐IM system over Rayleigh and Nakagami‐ m fading channels. Two well‐known detectors, the maximum likelihood (ML) detector and the log‐likelihood ratio (LLR) detector are used under the effect of the IQI at TxRx. Error performance analyzes over fading channels of the IQI effect on OFDM‐IM system are realized first theoretically and then by computer simulations. Results obtained for the presence of IQI at TxRx show that a performance evaluation based only on the presence of IQI in the receiver would be optimistic and misleading in terms of the performance of real‐life OFDM‐IM systems. [ABSTRACT FROM AUTHOR]

Summary: This paper addresses the problem of fixed‐time (F‐T) control for unmanned aerial vehicle (UAV) formation under unknown input disturbances to achieve moving target tracking. First, a kinematic model with uncertainties is employed to analyze the transient response of the UAV formation accurately. Next, based on a fast F‐T lemma, an F‐T disturbance observer is constructed to estimate the unknown disturbances. Subsequently, based on the designed observer and fast F‐T lemma, a distributed F‐T guidance law that controls multi‐UAV to track a moving target in a desired formation is introduced. Then, through rigorous mathematical proof, it is established that the control strategy enables the formation system to achieve F‐T stability, and the convergence time is independent of the system's initial states. Finally, the validity of the proposed control method is demonstrated through numerical simulation and presented in a realistic visual simulation scenario created using Unreal Engine 4 (UE4). [ABSTRACT FROM AUTHOR]