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This article presents the author’s response to Richard Arend’s commentary on their 2024 paper “Programs of Experimentation and Pivoting for (Overconfident) Entrepreneurs.“ Specifically the author’s respond to Arend’s question on the appropriateness of computational models as theory-building tools.

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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]

In this work, we determine the dissociation line of the nitrogen (N2) hydrate by computer simulation using the TIP4P/Ice model for water and the TraPPE force field for N2. This work is the natural extension of Paper I, in which the dissociation temperature of the N2 hydrate has been obtained at 500, 1000, and 1500 bar [Algaba et al., J. Chem. Phys. 159, 224707 (2023)] using the solubility method and assuming single occupancy. We extend our previous study and determine the dissociation temperature of the N2 hydrate at different pressures, from 500 to 4500 bar, taking into account the single and double occupancy of the N2 molecules in the hydrate structure. We calculate the solubility of N2 in the aqueous solution as a function of temperature when it is in contact with a N2-rich liquid phase and when in contact with the hydrate phase with single and double occupancy via planar interfaces. Both curves intersect at a certain temperature that determines the dissociation temperature at a given pressure. We observe a negligible effect of occupancy on the dissociation temperature. Our findings are in very good agreement with the experimental data taken from the literature. We have also obtained the driving force for the nucleation of the hydrate as a function of temperature and occupancy at several pressures. As in the case of the dissociation line, the effect of occupancy on the driving force for nucleation is negligible. To the best of our knowledge, this is the first time that the effect of the occupancy on the driving force for nucleation of a hydrate that exhibits sII crystallographic structure is studied from computer simulation. [ABSTRACT FROM AUTHOR]

In this article, we present a mathematical model and numerical simulation of the coffee-ring effect on porous papers. The numerical method is based on Monte Carlo simulation. The proposed model is simple but can capture the main mechanism of coffee stain formation on porous papers. Several numerical experiments are presented to demonstrate the performance of the proposed algorithm. We can obtain the coffee-ring effect on porous papers as the computer simulation results. [ABSTRACT FROM AUTHOR]

Capillary wicking in a thicker gel blot microfluidics paper has been investigated through a combination of an analytical framework, experiments, and numerical simulations. The primary objectives of this work are to investigate the concentration-dependent wicking process inside thicker microfluidic paper and to estimate the concentration-dependent permeability using both theoretical models and experimental data. An additional goal is to estimate the parameters for saturation-dependent flow modeling in thicker microfluidic paper. To comprehend the wicking phenomenon on thicker gel blot paper, a series of experiments employing aqueous food dye solutions at varying concentrations has been conducted. In order to calculate the temporal wicking length analytically, the Brinkman-extended Darcy equation is implemented. By modifying the permeability expression for a simple rectangular unidirectional fiber cell and pure liquid, the expression of effective permeability for the analytical framework has also been introduced. The concentrations of the food dye solutions appear to have a substantial influence on the wicking phenomenon. Effective permeability and wicking length have been found to follow a decreasing pattern at lower concentrations while both increase at higher values. Intriguingly, employing a microfluidics paper with a relatively greater thickness facilitates the visualization of the fluid front. This phenomenon is identified by the formation of an acute angle at intermediate time instants, while the fluid front angle assumes an angle nearly ∼90° during smaller and higher time instants. In order to evaluate the saturation-dependent capillary pressure and permeability, the empirical correlation of concentration-dependent Brooks and Corey parameters is additionally determined experimentally. These parameters are subsequently employed in numerical simulations to illustrate the saturation-dependent flow field using Richards' equation. Furthermore, numerical simulations based on these estimated model parameters have been conducted, and it turns out that the saturation field has an excellent agreement with the experimental results. The results of the current study can be used to design low-cost paper-based diagnostic devices for usage in healthcare and environmental applications. [ABSTRACT FROM AUTHOR]

Accurate identification of structural displacements is important for structural state assessment and performance evaluation. This paper proposes a real-time structural displacement detection model based on computer vision and deep learning. The model consists of three stages: identification, tracking, and displacement resolution. First, the displacement target is identified and tracked by the improved YOLO v7 algorithm and the improved DeepSORT algorithm. Then, the Euclidean distance method based on inverse perspective mapping (IPM-ED) is proposed for the analytical conversion of the displacement. Next, the accuracy and effectiveness of this displacement detection model are evaluated through four groups of bamboo axial compression tests. A comparative analysis is conducted between the IPM-ED displacement analysis method and the commonly used ED displacement analysis method. Finally, the robustness of this method is tested by using a cable breakage test of a cable dome structure as an application case. The research results demonstrate that the maximum average error of the four groups of bamboo displacement tests is only 3.10 mm, and the maximum relative error of peak displacement is only 6.54 mm. The RMSE basically stays around 3.5 mm. The maximum displacement error in the application case is only 4.91 mm, with a maximum MAPE of 4.94%. In addition, the error percentage under the IPM-ED algorithm is basically within 5%, while the error percentage of the ED algorithm is more than 10%. The method in this paper achieves efficient and intelligent identification of structural displacements in a non-contact manner. The proposed method is suitable for environments where the contact displacement sensor is easily affected by vibration, the site is complex and requires additional displacement sensor fixing equipment, the displacement sensor with super-high structure is unsafe to deploy, and the contact displacement sensor in narrow space is inconvenient to deploy, so it has broad application prospects. [ABSTRACT FROM AUTHOR]

Deep water areas with soft subsea soils, conventional surface conductor into the mud depth is too deep, long waiting time for resting, prone to surface conductor sinking and submerged wellhead instability. In this paper, based on the basic principles of mechanics and the understanding of the structure of the surface conductor, a mechanical model of the bearing capacity of the surface conductor is established. Three types of expandable surface conductors were designed by changing the distribution of the expansion material, in contrast to conventional surface conductors. The bearing characteristics of different structural surface conductors are also investigated by changing the soil parameters from the strength of the submarine soil. The study has obtained: the load-bearing capacity comparison graph between conventional surface conductor and expandable surface conductor; the load-bearing capacity change of expandable surface conductor under the change of soil parameters and the change of expansion material section; and the load-bearing capacity improvement effect of the three expandable surface conductors designed in the paper compared with conventional surface conductors, using stress as the evaluation criterion. This paper provides technical support for the design of expandable surface conductors and provides a basis for numerical simulation of surface well construction. [ABSTRACT FROM AUTHOR]

Alternating current (ac) losses in conductor-on-rounded-core (CORC) cables of YBCO high-temperature superconducting (HTS) tapes are a significant challenge in HTS power applications. This study employs two finite element analysis (FEA) models to investigate the contributions from different ac loss components and provide approaches for reducing ac losses in cables. An FEA model based on the T-A formulation treats the cross section of thin superconducting layers as 1D lines and, therefore, only can predict the ac loss generated by the perpendicular magnetic field. In contrast, the model based on H-formulation can be performed on the actual 2D rectangular cross section HTS tapes to provide the total ac losses generated by magnetic fluxes penetrating from both the edges and surfaces of HTS tapes, although this model requires more computing time and memory. The 1D and 2D simulation models were validated by cross comparing the results from both models and by comparing sub-section and full cross section models. Subsequently, two models relate cable design and operational parameters to the surface and edge losses of a two-layer CORC cable by considering the (1) relative contributions of edge and surface losses to the overall ac losses; (2) effect of the current distribution between inner and outer HTS layers on ac losses; (3) impact of the tape alignment on ac losses in each HTS layer; (4) influence of the thickness of HTS layers on ac losses; (5) effect of size and number of inter-tape gaps on ac losses; and (6) contribution frequency on the ac losses. The research results given in this paper are therefore not only valuable to suggest strategies for reducing ac loss in multi-layer cables but also for developing more accurate and effective methods to calculate ac loss in CORC HTS cables. [ABSTRACT FROM AUTHOR]

This paper aims at proposing a calculation model to deal with the face stability of shield tunnels in unsaturated soil. Based on the existing results of centrifugal test and numerical simulation, a new failure mechanism is proposed, which combines the logarithmic spiral with upper loosening arch mechanisms. The failure mechanism considers the influence of the soil arching effect and the logarithmic spiral height coefficient. Formulas for calculating the loosening earth pressure of unsaturated soil are deduced. Subsequently, this model of loosening earth pressure is introduced into an analytical model to compute the limit support pressure on the tunnel face. Compared with other height coefficients and the degree of soil arching effect, when the height coefficient is 0.95 and the degree of soil arching effect is 10%–30%, the limit support pressure proposed in this paper is in good agreement with the centrifugal test results. Finally, comparisons are performed with the proposed model and classical models as well as typical centrifuge model tests. The comparative analysis shows that the proposed theoretical model is in good agreement with the numerical simulation. The outline of the failure zone by the theoretical model in this paper is in good agreement with the centrifuge results. [ABSTRACT FROM AUTHOR]

The access of new energy improves the flexibility of distribution network operation, but also leads to more complex mechanism of line loss. Therefore, starting from the nonlinear, fluctuating and multi-scale characteristics of line loss data, and based on the idea of decomposition prediction, this paper proposes a new method of line loss frequency division prediction based on wavelet transform and BIGRU-LSTM (Bidirectional Gated Recurrent Unit-Long Short Term Memory Network).Firstly, the grey relation analysis and the improved NARMA (Nonlinear Autoregressive Moving Average) correlation analysis method are used to extract the non-temporal and temporal influencing factors of line loss, and the corresponding feature data set is constructed. Then, the historical line loss data is decomposed into physical signals of different frequency bands by using wavelet transform, and the multi-dimensional input data of the prediction network is formed with the above characteristic data set. Finally, the BIGRU-LSTM prediction network is built to realize the probabilistic prediction of high-frequency and low-frequency components of line loss. The effectiveness and applicability of the method proposed in this paper were verified through numerical simulation. By dividing the line loss data into different frequency bands for frequency prediction, the mapping relationship between different line loss components and influencing factors was accurately matched, thereby improving the prediction accuracy. [ABSTRACT FROM AUTHOR]

Plastic deformation forming with metal pipe blanks by contact blast loading inside pipes is an interesting moldless forming technique, also a complex and error-prone process. Some advantages are very characteristic of this forming technique such as no cost of mold, tooling and low energy consumption, no complicated control equipment compared to other forming techniques such as casting, rolling, tube hydrostatic forming, bending - welding. Up to now, the calculation and design of this forming technique mainly use some existing reference empirical formulas, so the experimental results are only suitable in the range of small pipe diameters, and still there are significant deviations for larger pipe diameters. In order to increase the predictability and accuracy of forming process by contact blast loading inside large pipes, this paper presents a study on the influence of the mass of highly explosive material - TNT to the forming ability of large steel pipes from API-5LX-42 mild steel materials by modern 3D numerical simulation using Abaqus/Cae software. Four output criteria with maximum values are used to evaluate the efficiency of this forming process, includ- ing maximum diameter of the blast zone (Dmax ≤2*Do), Von Mises stress (Smax ≤UTS), Hoop plastic strain component (PE22 max ≤1), and Pipe wall thinning rate (€7-max ≤60%). The results of this research on the plastic deformation forming process using numerical simulation can be used for the next experimental step to evaluate the difference between simulation and experiment, as well as use this data in the calculation and design of pipe products with circular or square cross-sections to save both time and money of trial and error before application in actual manufacturing. [ABSTRACT FROM AUTHOR]

A critical challenge of any blast simulation facility is in producing the widest possible pressure-impulse range for matching against equivalent high-explosive events. Shock tubes and blast simulators are often constrained with the lack of effective ways to control blast wave profiles and as a result have a limited performance range. Some wave shaping techniques employed in some facilities are reviewed but often necessitate extensive geometric modifications, inadvertently cause flow anomalies, and/or are only applicable under very specific configurations. This paper investigates controlled venting as an expedient way for waveforms to be tuned without requiring extensive modifications to the driver or existing geometry and could be widely applied by existing and future blast simulation and shock tube facilities. The use of controlled venting is demonstrated experimentally using the Advanced Blast Simulator (shock tube) at the Australian National Facility of Physical Blast Simulation and via numerical flow simulations with Computational Fluid Dynamics. Controlled venting is determined as an effective method for mitigating the impact of re-reflected waves within the blast simulator. This control method also allows for the adjustment of parameters such as tuning the peak overpressure, the positive phase duration, and modifying the magnitude of the negative phase and the secondary shock of the blast waves. This paper is concluded with an illustration of the potential expanded performance range of the Australian blast simulation facility when controlled venting for blast waveform tailoring as presented in this paper is applied. [ABSTRACT FROM AUTHOR]

This paper considers theoretical foundations and mathematical methods of data analysis under the conditions of the Rice statistical distribution. The problem involves joint estimation of the signal and noise parameters. It is shown that this estimation requires the solution of a complex system of essentially nonlinear equations with two unknown variables, which implies significant computational costs. This study is aimed at mathematical optimization of computer algebra methods for numerical solution of the problem of Rician data analysis. As a result of the optimization, the solution of the system of two nonlinear equations is reduced to the solution of one equation with one unknown variable, which significantly simplifies algorithms for the numerical solution of the problem, reduces the amount of necessary computational resources, and enables the use of advanced methods for parameter estimation in information systems with priority of real-time operation. Results of numerical experiments carried out using Wolfram Mathematica confirm the effectiveness of the developed methods for two-parameter analysis of Rician data. The data analysis methods considered in this paper are useful for solving many scientific and applied problems that involve analysis of data described by the Rice statistical model. [ABSTRACT FROM AUTHOR]

In this paper, the qualitative behaviors of an important four-dimensional Lorenz system with wild pseudohyperbolic attractor that proposed in (Gonchenko et al 2021 Nonlinearity 34 2018–47) are considered. Here, we prove that the four-dimensional Lorenz system with varying parameters is global bounded according to Lyapunov's direct method. Furthermore, we provide a collection of global absorbing sets, where in addition we obtain the rate of the trajectories going from the exterior to the global absorbing set. In particular, we solve the critical case k → 0 + that cannot be resolved by using the previous methods. The fundamental qualitative behaviors are analyzed theoretically and numerically. We present bifurcation diagrams to further explore the complicated dynamical behaviors of this system. The period-doubling bifurcation phenomenon is found. To illustrate the efficiency of our method, we present numerical simulations to show the validity of our research results. Finally, we present some applications of our research results in this paper. [ABSTRACT FROM AUTHOR]

In this paper, flow over a cluster of three equally spaced circular cylinders was studied by numerical simulation based on the turbulence model k-kl-ω for two incidence angles β = 0° and 60°, at different Reynolds numbers, and flow interference pattern characteristics between cylinders, characteristics of force parameters, and Strouhal number of each cylinder with different spacing ratios ranging from 1.5 to 4 at Re 8 × 104, 2 × 105 and 2 × 106 were obtained. Analyzing the flow field around three cylinders, the following results have been obtained: (1) at incidence angle β = 0° and 60°, the wake was nearly symmetrical if S/D ≥ 2.0; (2) at β = 60°, S/D = 1.5, and Re = 2 × 105, an asymmetric periodic flow pattern occurred in the wake region which produced a significant effect on the surface mechanical parameters and Strouhal number, and this was observed for the first time. The periodic flow regime of the wake region also occurred at S/D = 1.35 and 1.5, without the same phenomenon at S/D = 1.7 and 2.0; this phenomenon is described for the first time in this paper; (3) the phenomenon of periodic flow regime in the wake region was intrinsic and related to Reynolds number and space ratio. In addition, the characteristics of force parameters of three cylinders were mainly affected by the interference between cylinders, at 1.5 < S/D < 4, which indicated that the drag coefficient of three cylinders reduces with different Reynolds numbers and increases with enlargement of the spacing ratio for upstream cylinders at incidence angle 0°. At incidence angle 60° and S/D = 1.5~4, the Strouhal number decreases with the enlargement of spacing ratio for the upstream cylinders, but the Strouhal number increases for the downstream cylinder, which is another prominent flow interference influence. The results indicated the effect of flow interference between cylinders subjected to a cross flow over a cluster of three equally spaced cylinders, considering the flow pattern, surface mechanical parameters and Strouhal number, which should be considered in the establishment of standard design codes in fields such as offshore wind turbine engineering for flow interference around groups of cylinders. [ABSTRACT FROM AUTHOR]

This paper investigates the practical generalized finite-time synchronization (PGFETS) of duplex networks with quantized and delayed couplings. Given that continuous transmission of signals will increase the load and cost of communication, we introduce quantized couplings in the model. Then, via the theorem of finite-time stability, the PGFETS is proposed based on the fact that PGFETS is much more extensive and practical than classical finite-time synchronization. Some sufficient criteria are formulated to achieve the goal of synchronization by utilizing quantized intermittent control schemes. Lastly, the validity of the theoretical results is illustrated by numerical simulations. [ABSTRACT FROM AUTHOR]

In order to enhance the stability of the tilt transition process, a new configuration of Quad-Tiltrotor UAV was presented in this paper. Firstly, numerical simulation was used to calculate and analyze the aerodynamic interaction between the front rotor/fuselage/rear rotor during the transition state mode. The calculation model of the isolated rotor, front-rear rotor, front rotor-fuselage, and front rotor-rear rotor-fuselage combination states are established. Besides, the effects of pitch, roll, and yaw moment on the fuselage at different tilt angles are analyzed. It is concluded that the front rotor is the leading factor in the aerodynamic interference of the whole UAV in the different combination states. The research results can provide a reference for the optimization design of the overall layout, structure, and flight control strategy of the cross-shaped quad-tiltrotor UAV, and can also provide solutions for the logistics application of urban air traffic. [ABSTRACT FROM AUTHOR]

Asymmetric airfoils are commonly used in horizontal axis wind turbines, while symmetrical airfoils are currently the focal point of the researches for most vertical axis wind turbines' airfoils studies. The purpose of this paper is to research the influence of asymmetric airfoils on the aerodynamic performance of vertical axis wind turbines. The influence of asymmetric airfoils on the aerodynamic characteristics of vertical axis wind turbines is investigated by numerical simulation method. The symmetric airfoils are chosen as NACA0021, while the asymmetric airfoils are chosen as DU97-W-300. Single-blade, 3-blade, different tip speed ratios, and three wind speeds (7, 8, 9 m/s) are set as the parameters. The wind turbine with symmetric airfoils performed better aerodynamically at high tip speed ratios, whereas the wind turbine with asymmetric airfoils performs well at low tip speed ratios. The wind turbine with asymmetric airfoils has outstanding start ability at low wind speeds. [ABSTRACT FROM AUTHOR]

Purpose: The purpose of this paper is to propose a method that can calculate the transportation infrastructure network service capacity enhancement given by planned transportation infrastructure projects construction. Managers can sequence projects more rationally to maximize the construction effectiveness of infrastructure investments. Design/methodology/approach: This paper designed a computational network simulation software to generate topological networks based on established rules. Based on the topological networks, the software simulated the movement path of users and calculated the average travel time. This software allows the adjustment of parameters to suit different research objectives. The average travel time is used as an evaluation index to determine the most appropriate construction sequence. Findings: In this paper, the transportation infrastructure network of Sichuan Province in China was used to demonstrate this software. The average travel time of the existing transportation network in Sichuan Province was calculated as 211 min using this software. The high-speed railways from Leshan to Xichang and from Xichang to Yibin had the greatest influence on shortening the average travel time. This paper also measured the changes in the average travel time under two strategies: shortening the maximum and minimum priorities. All the transportation network optimisation plans for Sichuan Province will be somewhere between these two strategies. Originality/value: The contribution of this research are three aspects: First, a complex network analysis method that can take into account the differences of node elements is proposed. Second, it provides an effective tool for decision makers to plan transportation infrastructure construction. Third, the construction sequence of transportation infrastructure development plan can effect the infrastructure investment effectiveness. [ABSTRACT FROM AUTHOR]

Explosively formed projectile (EFP) has the advantages of high flight speed, high burst height, insensitivity to initial velocity, etc. To study the forming performance of multiple explosively formed projectile (MEFP) and to analyze the factors influencing the forming results. A directional pentagonal prism MEFP with five liners is proposed in this paper. Experiments were conducted to validate the performance of this MEFP. The experimental results show that the generated EFPs have high flight speeds. However, the EFP hit position on the target plate was offset, causing multiple positional penetrations. To analyze the causes of the phenomenon, a numerical simulation model of directional MEFP is established and the forming process of MEFP is numerically simulated. The simulation results indicate that the EFP fracture occurs during the forming process due to the asymmetric detonation wave, and its tail cannot be fully closed. Combined with the numerical simulation and experimental results, the forming performance of the liners used in the MEFP has been further developed. Further analysis was carried out on the effect of liner thickness and height on forming performance. It can be seen that as the thickness of the liners increases, the length of the head of EFP increase, the incidence of EFP tail fracture decreased, the aspect ratio increases and the EFP velocity decrease. As the height of the MEFP increases, the velocity of the EFP increases, the head ratio increases, the shape of the detonation wave tends to be symmetrical, and the tendency of the EFP to appear as an unclosed tail decreases. [ABSTRACT FROM AUTHOR]

As cyberattacks become increasingly sophisticated and frequent, it is crucial to develop robust cybersecurity measures that can withstand adversarial attacks. Adversarial simulation is an effective technique for evaluating the security of systems against various types of cyber threats. However, traditional adversarial simulation methods may not capture the complexity and unpredictability of real-world cyberattacks. In this paper, we propose the improved deep reinforcement learning (DRL) algorithm to enhance adversarial attack simulation for cybersecurity with real-world scenarios from MITRE-ATT&CK. We first describe the challenges of traditional adversarial simulation and the potential benefits of using DRL. We then present an improved DRL-based simulation framework that can realistically simulate complex and dynamic cyberattacks. We evaluate the proposed DRL framework using a cyberattack scenario and demonstrate its effectiveness by comparing it with existing DRL algorithms. Overall, our results suggest that DRL has significant potential for enhancing adversarial simulation for cybersecurity in real-world environments. This paper contributes to developing more robust and effective cybersecurity measures that can adapt to the evolving threat landscape of the digital world. [ABSTRACT FROM AUTHOR]

In this paper, we first present multiple numerical simulations of the anti-symmetric matrix in the stability criteria for fractional order systems (FOSs). Subsequently, this paper is devoted to the study of the admissibility criteria for descriptor fractional order systems (DFOSs) whose order belongs to (0, 2). The admissibility criteria are provided for DFOSs without eigenvalues on the boundary axes. In addition, a unified admissibility criterion for DFOSs involving the minimal linear matrix inequality (LMI) variable is provided. The results of this paper are all based on LMIs. Finally, numerical examples were provided to validate the accuracy and effectiveness of the conclusions. [ABSTRACT FROM AUTHOR]

In this paper, the combustion conditions in the boiler furnace of a 660 MW tangential fired pulverized coal boiler are numerically simulated at 15% and 20% rated loads, to study the flexibility of coal-fired power units on ultra-low load operation. The numerical results show that the boiler can operate safely at 15% and 20% ultra-low loads, and the combustion condition in the furnace is better at 20% load, and the tangent circles formed by each characteristic section in the furnace are better, and when the boiler load is decreased to 15%, the tangent circles in the furnace begin to deteriorate. The average flue gas temperature of different areas of the furnace shows that when the boiler furnace operates under ultra-low load conditions, the average smoke temperature of the cold ash hopper at 20% load is basically the same as the average smoke temperature at 15% load; in the burner area, the average smoke temperature of the cold ash hopper at 20% load is about 50 K higher than that at 15% load; in the burned out area, the average smoke temperature of the cold ash hopper at 20% load is slightly higher than that at 15% load. The average temperature of flue gas in the furnace showed a tendency to increase rapidly with the height of the furnace, then slow down and fluctuate the temperature in the burner area, and finally increase slightly in the burnout area due to the further combustion of combustible components to release heat, and then began to decrease. [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]

This work investigates a prey–predator model featuring a Holling-type II functional response, in which the fear effect of predation on the prey species, as well as prey refuge, are considered. Specifically, the model assumes that the growth rate of the prey population decreases as a result of the fear of predators. Moreover, the detection of the predator by the prey species is subject to a delay known as the fear response delay, which is incorporated into the model. The paper establishes the preliminary conditions for the solution of the delayed model, including positivity, boundedness and permanence. The paper discusses the existence and stability of equilibrium points in the model. In particular, the paper considers the discrete delay as a bifurcation parameter, demonstrating that the system undergoes Hopf bifurcation at a critical value of the delay parameter. The direction and stability of periodic solutions are determined using central manifold and normal form theory. Additionally, the global stability of the model is established at axial and positive equilibrium points. An extensive numerical simulation is presented to validate the analytical findings, including the continuation of the equilibrium branch for positive equilibrium points. [ABSTRACT FROM AUTHOR]

To solve the control problem of time-varying state-scale nonlinear systems whose initial state is not affected by settling time, fixed-time convergence algorithms are proposed for first-order systems and higher-order systems in this paper. First, a scalar model is used to illustrate how the time-varying feedback parameter can guarantee that the system achieves asymptotic stability while achieving finite-time convergence, and it is proved that the settling time obtained in this paper is only related to the prescribed boundary. This allows us to design the settling time with an appropriate parameter based on the prescribed boundary. To exhibit the effectiveness and extensibility of the proposed algorithm for first-order scalar systems, the results are subsequently extended to general higher-order systems based on the backstepping method. By introducing numerical simulation results, this paper verifies that the proposed algorithm will make the system achieve asymptotic stability and its output can converge to a given boundary, regardless of the system's initial states. [ABSTRACT FROM AUTHOR]

The emergence of virtual reality (VR) simulation has brought about a significant shift in the healthcare industry, as it integrates modern technologies with human talents to foster patient-centered care, clinical efficiency, and a compassionate healthcare digital ecosystem. The use of clinical simulation in nursing education has become essential in the current day, revolutionizing the training of future medical professionals. This paper explored the realm of simulation-based learning, illuminating its importance, obstacles, and endless potential in the field of nursing education. Given the ever-changing healthcare landscape, nurses need to possess a broad range of skills and a thorough comprehension of real-world situations. But conventional didactic methods frequently fail to adequately prepare student-nurses for the intricacies of clinical practice. VR is one of the most crucial elements of immersive learning that increases constructive pedagogic engagements due to generative imagination it offers. By using VR headgear or goggles, student-nurses can fully submerge themselves in a customized digital world as if they were truly there, interacting with their surroundings and learn in an interactive and pedagogic informative digital ecosystem. In order to help student-nurses practice problem-solving techniques without really placing themselves in risk, VR can also be used to construct very realistic simulations. In this study, the authors offered the transformative potential of VR, with significances to improve nursing education by offering engaging and interactive learning environments. The paper presented a novel approaches in addressing nursing education through technology familiarization, proposing a cutting-edge simulation platform using actor network (ANT) model for the resource distribution. [ABSTRACT FROM AUTHOR]

Traffic signal control (TSC) plays a crucial role in enhancing traffic capacity. In recent years, researchers have demonstrated improved performance by utilizing deep reinforcement learning (DRL) for optimizing TSC. However, existing DRL frameworks predominantly rely on manually crafted states, actions, and reward designs, which limit direct information exchange between the DRL agent and the environment. To overcome this challenge, we propose a novel design method that maintains consistency among states, actions, and rewards, named uniformity state-action-reward (USAR) method for TSC. The USAR method relies on: 1) Updating the action selection for the next time step using a formula based on the state perceived by the agent at the current time step, thereby encouraging rapid convergence to the optimal strategy from state perception to action; and 2) integrating the state representation with the reward function design, allowing for precise assessment of the efficacy of past action strategies based on the received feedback rewards. The consistency-preserving design method jointly optimizes the TSC strategy through the updates and feedback among the Markov elements. Furthermore, the method proposed in this paper employs a residual block into the DRL model. It introduces an additional pathway between the input and output layers to transfer feature information, thus promoting the flow of information across different network layers. To assess the effectiveness of our approach, we conducted a series of simulation experiments using the simulation of urban mobility. The USAR method, incorporating a residual block, outperformed other methods and exhibited the best performance in several evaluation metrics. [ABSTRACT FROM AUTHOR]

With the advancement of technology, social media has become an integral part of people's daily lives. This has resulted in the emergence of a new group of individuals known as "professional operation people". These individuals actively engage with social media platforms, taking on roles as content creators, influencers, or professionals utilizing social media for marketing and networking purposes. Therefore, in this article, we designed a six-dimensional fractional-order social media addiction model (FOSMA) in the sense of Caputo, which took into account the professional operations population. Initially, we established the positivity and boundedness of the FOSMA model. After that, the basic regeneration number and the equilibrium points (no addiction equilibrium point and addiction equilibrium point) were computed. Then, the local asymptotic stability of the equilibrium points were proved. In order to investigate the bifurcation behavior of the model when R 0 = 1 , we extended the Sotomayor theorem from integer-order to fractional-order systems. Next, by the frequency analysis method, we converted the fractional order model into an equivalent partial differential system. The tanh function was introduced into the scheme of sliding mode surface. The elimination of addiction was achieved by the action of the fractional order sliding mode control law. Finally, simulation results showed that fractional order values, nonlinear transmission rates, and specialized operating populations had a significant impact on predicting and controlling addiction. The fractional-order sliding mode control we designed played an important role in eliminating chatter, controlling addiction, and ensuring long-term effectiveness. The results of this paper have far-reaching implications for future work on modeling and control of fractional-order systems in different scenarios, such as epidemic spread, ecosystem stabilization, and game addiction. With the advancement of technology, social media has become an integral part of people's daily lives. This has resulted in the emergence of a new group of individuals known as "professional operation people". These individuals actively engage with social media platforms, taking on roles as content creators, influencers, or professionals utilizing social media for marketing and networking purposes. Therefore, in this article, we designed a six-dimensional fractional-order social media addiction model (FOSMA) in the sense of Caputo, which took into account the professional operations population. Initially, we established the positivity and boundedness of the FOSMA model. After that, the basic regeneration number and the equilibrium points (no addiction equilibrium point and addiction equilibrium point) were computed. Then, the local asymptotic stability of the equilibrium points were proved. In order to investigate the bifurcation behavior of the model when we extended the Sotomayor theorem from integer-order to fractional-order systems. Next, by the frequency analysis method, we converted the fractional order model into an equivalent partial differential system. The tanh function was introduced into the scheme of sliding mode surface. The elimination of addiction was achieved by the action of the fractional order sliding mode control law. Finally, simulation results showed that fractional order values, nonlinear transmission rates, and specialized operating populations had a significant impact on predicting and controlling addiction. The fractional-order sliding mode control we designed played an important role in eliminating chatter, controlling addiction, and ensuring long-term effectiveness. The results of this paper have far-reaching implications for future work on modeling and control of fractional-order systems in different scenarios, such as epidemic spread, ecosystem stabilization, and game addiction. [ABSTRACT FROM AUTHOR]

The challenge in designing distributed controllers for vehicle platoon synchronization arises when full-state information for control algorithm calculations cannot be obtained from the entire vehicle. Therefore, this paper presents a control scheme using a cooperative observer to estimate full-state information, enabling its use in calculating control signals. Instead of relying solely on a control signal proportional to the cooperative tracking error, the proposed control signal includes an additional integral form of the cooperative tracking error. This addition is expected to mitigate the effects of disturbances experienced by follower vehicles. Distributed control generally comprises two major components: The proportional-integral (PI) controller and the cooperative observer. The paper provides conditions for choosing control parameter values to guarantee the stability of the vehicle platoon. A numerical simulation of a vehicle platoon comprising one leader and ten followers is presented to demonstrate performance and validate the research results. Simulation results indicate that the controller performs effectively when followers experience constant disturbances, demonstrating the continuous achievement of vehicle platoon synchronization. [ABSTRACT FROM AUTHOR]

This paper deals with the problem of non-fragile H∞ filter design for a class of neutral Markovian jump systems with parameter uncertainties and time-varying delays. The parameter uncertainties are norm-bounded, and time-varying delays include state and neutral time-varying delays. First, by selecting the appropriate stochastic Lyapunov-Krasovskii functional and using the integral inequality technique, sufficient conditions are obtained to make the filtering error system not only stochastically stabilized, but also mode and delay dependent. Second, by the utilizing linear matrix inequality method, sufficient conditions are obtained for the filtering error system to be stochastically stable and to have a prescribed H∞ performance level γ. Based on this result, by processing the uncertainty terms, sufficient conditions for the existence of the filter are obtained, and mode-dependent filter parameters are given. Finally, by numerical simulation, the feasibility and validity of the theoretical results are verified. [ABSTRACT FROM AUTHOR]

The significance of Regional Innovation Systems (RIS) as a strategic tool for enhancing a region's competitiveness has been increasingly recognized. This paper presents a model of RIS that was developed using the system dynamics (SD) methodology. The goal of this model is to amalgamate the systemic approach with computer modeling and simulation disciplines into a comprehensive dynamic framework for analyzing RIS. Within this framework, the paper explores the impact of smart technologies on regional development through the RIS. Specifically, the SD model serves as an 'experimental tool' for conducting extensive what-if scenario analyses concerning smart technologies. The efficacy of these technologies is examined in terms of their dynamic influence on regional development, with insights derived from simulation outcomes. Data from two Greek regions provides a strategic analysis over a designated time horizon. [ABSTRACT FROM AUTHOR]

Numerical simulations have been widely used to study the failure and mechanical behavior of high performance fiber-reinforced concretes (HPFRCs) in the past decades. According to different algorithms principles of these numerical modeling methods, this paper categorized these methods into mesh-based, particle-based, and lattice-based approaches. The main benefits and limitations of each method were introduced and analyzed with a particular focus on their application to HPFRCs. A comprehensive overview of the numerical modeling methods and their applications at macro-, meso-, and multiscale levels to study the failure of HPFRCs is presented. The paper discusses current trends and challenges in further research on numerical modeling methods for HPFRC failure, exploring novel approaches such as machine learning or AI within the context of numerical modeling. The aim of this paper is to provide scientific guidance and practical tools for studying the failure of HPFRCs through numerical simulation. [ABSTRACT FROM AUTHOR]

In recent years, heat release associated with the detonation phenomenon is considered a very efficient process. Pressure gain combustors are being developed with detonation waves as the driving force. In this scenario, study of detonation waves has become very important. Deflagration-to-Detonation transition (DDT) is one of the ways used to initiate detonation in the combustors. An attempt has been made in this paper to study the DDT in a tube with obstacles using OPENFOAM. A 2-dimensional rectangular section of a tube containing obstacles filled with stoichiometric hydrogen-air mixtures at different initial conditions have been studied. The effect of changes in the length of the tube, number of obstacles, blockage ratios and initial pressure of the reactants on the detonation wave properties have been studied using numerical simulation based on ddtfoam software. The motivation for this study is to design a pre-detonator for a rotating detonation engine (RDE). In order to make it compatible with the RDE and the test facility, it has been proposed to carry out simulations using shorter lengths of the DDT tube. The number of obstacles has been selected appropriately to obtain detonation at shorter lengths of the tube of the order of 1.5 m, 1.0 m & 0.5 m. As the objective has been to obtain design data for the prototype, the finer details of DDT are not being discussed in this paper. [ABSTRACT FROM AUTHOR]

Over the past two decades, there has been a renewed interest in the development of a new generation of supersonic aircraft for civil purposes that could potentially succeed Concorde. However, the noise annoyance is still considered one of the hampering factors to meet public consensus. This paper aims at revealing the potential of numerical simulations to predict sonic boom signature in Near Field at early design stages. In particular, the paper further demonstrates the applicability of the numerical approach proposed by NASA and other partners during the Sonic Boom Prediction Workshops held between 2014 and 2021, to compute the pressure signature of aircraft in the zone close to it. The results highlight the suitability of the approach (1) to capture the impact of aircraft flight condition variations on the sonic boom signature, (2) to enable the characterization of novel aircraft layout, including Mach 5 waverider configuration, (3) to provide near-field shock wave noise predictions that can be used to evaluate shock propagation, on-ground signature analyses, and annoyance assessment. [ABSTRACT FROM AUTHOR]

Active disturbance rejection control (ADRC) is widely used in airborne optoelectronic stabilization platforms due to its minimal reliance on the mathematical model of the controlled object. The extended state observer (ESO) is the core of ADRC, which treats internal parameter variations and external disturbances as total disturbances, observes the disturbances as extended states, and then compensates them into the control loop to eliminate their effects. However, the ESO can only achieve a precise estimation of constant or slowly varying disturbances. When the disturbance is periodically changing, satisfactory results cannot be obtained. In this paper, a generalized high-order extended state observer (GHOESO) is proposed to achieve the precise estimation of known frequency sinusoidal disturbance signals and improve disturbance suppression levels. Through numerical simulations, a traditional ESO and GHOESO are compared in terms of disturbance observation capability and disturbance suppression ability for single and compound disturbances based on our prior knowledge of disturbance frequency. The effectiveness of the proposed GHOESO method is verified. Finally, the algorithm is applied to an airborne optoelectronic stabilization platform for a 1°/1 Hz swing experiment on a space hexapod swing table. The experimental results demonstrate the superiority of the GHOESO proposed in this paper. [ABSTRACT FROM AUTHOR]

Autonomous search is an ongoing cycle of sensing, statistical estimation, and motion control with the objective to find and localise targets in a designated search area. Traditionally, the theoretical framework for autonomous search combines sequential Bayesian estimation with information theoretic motion control. This paper formulates autonomous search in the framework of possibility theory. Although the possibilistic formulation is slightly more involved than the traditional method, it provides a means for quantitative modelling and reasoning in the presence of epistemic uncertainty. This feature is demonstrated in the paper in the context of partially known probability of detection, expressed as an interval value. The paper presents an elegant Bayes-like solution to sequential estimation, with the reward function for motion control defined to take into account the epistemic uncertainty. The advantages of the proposed search algorithm are demonstrated by numerical simulations. [ABSTRACT FROM AUTHOR]

In this paper, a fractional active disturbance rejection control (FADRC) scheme is proposed for remotely operated vehicles (ROVs) to enhance high-precision positioning and docking control in the presence of ocean current disturbances and model uncertainties. The scheme comprises a double closed-loop fractional-order PI λ D μ controller (DFOPID) and a model-assisted finite-time sliding-mode extended state observer (MFSESO). Among them, DFOPID effectively compensates for non-matching disturbances, while its fractional-order term enhances the dynamic performance and steady-state accuracy of the system. MFSESO contributes to enhancing the estimation accuracy through the integration of sliding-mode technology and model information, ensuring the finite-time convergence of observation errors. Numerical simulations and pool experiments have shown that the proposed control scheme can effectively resist disturbances and successfully complete high-precision tasks in the absence of an accurate model. This underscores the independence of this control scheme on accurate model data of an operational ROV. Meanwhile, it also has the advantages of a simple structure and easy parameter tuning. The FADRC scheme presented in this paper holds practical significance and can serve as a valuable reference for applications involving ROVs. [ABSTRACT FROM AUTHOR]

A lime–sand pile is a three-phase particle composite material composed of a lime matrix, sand, and a loess aggregate at the meso level. Establishing a random aggregate model that can reflect the actual aggregate gradation, content, and morphology is the premise of numerical simulations of the meso-mechanics of lime–sand piles. In this paper, the secondary development of Abaqus 2022 is realized by writing Python 3.12 scripts, and a parameterized three-phase mixed lime–sand pile random meso-spherical aggregate model is obtained. A meso-modeling idea of lime–sand piles is creatively proposed, the integrated-generation algorithm of a spherical aggregate of different materials is written, and the material's properties and mesh generation are given by the algorithm. Finally, a numerical simulation of temperature–expansion statics is carried out using an established mesoscopic model. Under different mixing ratios, the expansion force increases with an increase in the lime proportion. The increase in the expansion force is approximately 45% of that without an increased lime proportion. The simulated expansion forces are 8.81 kN, 12.61 kN, and 18.89 kN, respectively, which are similar to the experimental results for laboratory specimens, and the relative error is less than 3%. In the case of different height ratios, with increases in height, the change in the expansion force is very small, and the relative error between the simulated value and the experimental value is less than 2%, which further verifies the reliability of the mesoscopic random model of lime–sand piles. The model can be used to guide the practical application of engineering. [ABSTRACT FROM AUTHOR]

In this paper, we investigate an initial-boundary value problem of a reaction–diffusion equation in a bounded domain with a Robin boundary condition and introduce some particular parameters to consider the non-zero flux on the boundary. This problem arises in the study of mosquito populations under the intervention of the population replacement method, where the boundary condition takes into account the inflow and outflow of individuals through the boundary. Using phase plane analysis, the present paper studies the existence and properties of non-constant steady-state solutions depending on several parameters. Then, we prove some sufficient conditions for their stability. We show that the long-time efficiency of this control method depends strongly on the size of the treated zone and the migration rate. To illustrate these theoretical results, we provide some numerical simulations in the framework of mosquito population control. [ABSTRACT FROM AUTHOR]

This article introduces some efficient generalized class of factor-type exponential imputation techniques and their corresponding estimators using auxiliary information. Generalized ratio, product, and dual to ratio type exponential estimators are the special cases of our suggested imputation techniques. Biases and mean squared error expressions are derived up to the first order of large sample approximations. The proposed imputation techniques can be viewed as efficient extensions of the work of Singh and Horn [Compromised imputation in survey sampling. Metrika. 2000;51(3):267–276. doi: 10.1007/s001840000054], Singh and Deo [Imputation by power transformation. Statist Papers. 2003;44(4):555–579. doi: 10.1007/BF02926010], Toutenburg and Srivastava [Amputation versus imputation of missing values through ratio method in sample surveys. Statist Papers. 2008;49(2):237–247. doi: 10.1007/s00362-006-0009-4], Kadilar and Cingi [Estimators for the population mean in the case of missing data. Commun Stat Theory Methods. 2008;37(14):2226–2236. doi: 10.1080/03610920701855020], Singh [A new method of imputation in survey sampling. Statistics. 2009;43(5):499–511. doi: 10.1080/02331880802605114], Gira [Estimation of population mean with a new imputation methods. Appl Math Sci. 2015;9(34):1663–1672] and Singh et al. [An improved alternative method of imputation for missing data in survey sampling. J Stat Appl Probab. 2022;11(2):535–543. doi: 10.18576/jsap]. Our proposed estimators are compared with these estimators, including the mean, ratio, and regression imputation techniques. Thereafter, a numerical illustration and simulation study are conducted for a comparative study using real and simulated data sets, and the demonstration shows that our suggested estimators are the most efficient estimators. [ABSTRACT FROM AUTHOR]

Inspired by the emerging field of twistronics, moiré photonic structures have attracted great interest. In this paper, we introduce the concept of the moiré Kagome lattice (MKL), which arises from the overlapping of a Kagome lattice at a commensurable angle of 38.211°. MKL exhibits a significantly broader main photonic bandgap (PBG) when compared to the traditional Kagome lattice. Through numerical simulations, we delved into the adjustable properties of the PBG of MKL by varying lattice parameters, including filling factors and materials. Meanwhile, we also observed the presence of photonic flatbands within the MKL structure. Specifically, the emergence of a super flat isolated flatband aids in achieving single-mode omnidirectional lasers and enhancing the omnidirectional electromagnetic interaction of materials, thereby expanding the applications of moiré photonic crystals. [ABSTRACT FROM AUTHOR]

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In view of the present situation that the exhaust waste heat of the hot air hood in the paper drying section is too much and the environment is not friendly, a closed heat pump drying system model applied to the exhaust air hood is proposed and established. Effects of evaporation temperature and condensation temperature on supply air temperature, supply air moisture content, system performance coefficient (COP) and dehumidification energy consumption ratio (SMER) were studied. Results show that with the increase of condensation temperature, the supply air temperature is unchanged, and the moisture content of the supply air increase, while the COP and SMER of the system show a downward trend. The moisture content of supply air decrease with the increase of evaporation temperature, while the supply air temperature, COP and SMER all show an upward trend. Therefore, in order to improve the drying characteristics and improve the performance of the heat pump system, the condensation temperature can be reduced and the evaporation temperature can be increased. [ABSTRACT FROM AUTHOR]

The joints of bars composed of flanges and high-strength bolts are currently used in steel structures as simple and economical construction solutions. This paper presents some theoretical aspects regarding the behavior and calculation of joints with flanges and partially pre-tensioned bolts. The overloading of the pretensioned high-strength bolts produced by the tensile effort resulting from the external actions is usually neglected in the technical materials and in the design norms for constructions, as long this tensioning effort does not exceed the pretensioning force of the high-strength bolts. The overloading effort of the bolts can be evaluated theoretically by estimating the relative stiffness of the flanges and bolts and confirmed through experimental tests and computer simulations. This paper also theoretically and computationally analyzes a joint for a tensioned bar made up of pre-stressed high-strength bolts and end flanges. [ABSTRACT FROM AUTHOR]

Given the difficulty in accurately evaluating the fatigue performance of large composite wind turbine blades (referred to as blades), this paper takes the main beam structure of the blade with a rectangular cross-section as the simulation object and establishes a composite laminate rectangular beam structure that simultaneously includes the flange, web, and adhesive layer, referred to as the blade main beam sub-structure specimen, through the definition of blade sub-structures. This paper examines the progressive damage evolution law of the composite laminate rectangular beam utilizing an improved 3D Hashin failure criterion, cohesive zone model, B-K failure criterion, and computer simulation technology. Under static loading, the layup angle of the anti-shear web has a close relationship with the static load-carrying capacity of the composite laminate rectangular beam; under fatigue loading, the fatigue damage will first occur in the lower flange adhesive area of the whole composite laminate rectangular beam and ultimately result in the fracture failure of the entire structure. These results provide a theoretical reference and foundation for evaluating and predicting the fatigue performance of the blade main beam structure and even the full-size blade. [ABSTRACT FROM AUTHOR]

A complex dynamical network (CDN) can be considered as the composition system with the nodes subsystem (NS) and the links subsystem (LS), and both subsystems are coupled with each other. In this paper, two vector differential equations (VDE) are used to describe the dynamical behaviours of NS and LS, respectively, in which the dynamical behaviour of NS is considered as the VDE with the second derivative term (SDT). This paper mainly focuses on the dynamics of LS, which is represented as VDE with the intuitive topologic feature of outgoing links, and investigates the design of the tracking controller for NS and the auxiliary tracking objectives (ATO) for LS. Firstly, the dynamical models of NS and LS in CDN are proposed, and the corresponding assumptions are given. Secondly, based on Lyapunov stability theory, the controller of NS and the ATO of LS are designed so that the state of NS can asymptotically track the given reference signal. Finally, the effectiveness of the proposed control strategy in this paper is verified by the numerical simulation example with N two-links robots. Abbreviations: ATO: auxiliary tracking objectives; CDN: complex dynamical network; LS: links subsystem; MDE: matrix differential equation; NS: nodes subsystem; SDT:second derivative term; VDE: vector differential equation; [ABSTRACT FROM AUTHOR]