ABSTRACT With the improvement of the new energy penetration rate, the power grid presents the characteristics of a weak current network, and a series of unstable problems appear. Compared with the grid‐following inverter (GFLI), the grid‐forming inverter (GFMI) provides essential voltage and frequency stabilisation capabilities for weak grids and has received extensive attention. Under the condition that the grid frequency does not exceed the limit, in order to give consideration to the economy, it is hoped that the inverter can track the maximum power point (MPP) of new energy so as to improve the utilisation rate of new energy. However, the active power control bandwidth of GFMI is low, which cannot meet the requirements of MPP tracking control rapidity. Therefore, this paper proposes a fast power control strategy for GFMI: firstly, the active power control bandwidth is improved by a prefilter with leading characteristics; then, model reference is used to adaptively adjust the parameters of the prefilter to avoid the impact of grid impedance changes on bandwidth enhancement performance. With the proposed control, the GFMI can quickly adjust the output power and track the maximum power point of new energy without affecting the stability. Finally, experimental validation confirms the technical feasibility and performance superiority of the proposed strategy.
Nancy Ivett Paredes Teran, Gonzalo Fernando Olmedo Cifuentes, Bacca Bladimir
et al.
This research presents the validation of a novel software application designed to recognize primary emotions in individuals with Down syndrome (DS), to support therapeutic interventions through artificial intelligence. The research addresses the need for innovative technological tools that assist therapists in real-time emotional assessment during therapy sessions. The study’s objective was to validate the application’s effectiveness, reliability, and therapeutic usefulness in recognizing five spontaneous emotions (happiness, anger, sadness, surprise, and neutrality) in individuals with DS attending a specialized care institution. The study followed ethical protocols approved by the Ethics Committees in Colombia and Ecuador to achieve this. Data was collected during therapy sessions, and three research hypotheses were formulated to evaluate the application’s performance. Structural Equation Modeling (SEM), using SmartPLS, was employed to analyze the relationships between observed emotional responses and the system’s feedback. The results demonstrated that the application accurately identified the targeted emotions in real time, and 94% of participating therapists positively assessed its usefulness in clinical settings. This validation confirms that the software can provide valuable input for therapists, enabling the design of tailored strategies that address the emotional needs of individuals with DS. The findings support the growing evidence supporting integrating machine learning and deep learning technologies into therapeutic tools for vulnerable populations.
This study investigates the influence of curing methods on the mechanical properties and pore structure characteristics of concretes including Sulphate-Resisting Cement (SRC), Ordinary Portland Cement (OPC), and Blast-Furnace Slag Cement (BFSC). Two curing regimes were applied: water immersion (Method I) and controlled humidity (Method II) at 22 °C and 80 % RH, with twice-daily water sprinkled for 7 days. Concrete mixtures with a 0.4 water-to-cement ratio and 400 kg/m3 cement content were assessed in terms of fresh properties, including slump, air content, and unit weight. The hardened properties were evaluated through compressive, flexural, and tensile strength tests, in addition to pulse velocity and dynamic elastic modulus measurements. To examine the impact of curing conditions on porosity, Mercury Intrusion Porosimetry (MIP) was used to quantify cumulative intrusion volume, porosity, pore surface area, and average pore diameter. Unlike previous studies that primarily focus on compressive strength, this research uniquely investigates mechanical performance with pore structure variations induced by curing conditions, filling a critical gap in the existing literature. The findings confirm that Method I significantly improves mechanical properties, particularly for SRC, which achieved the highest compressive strength of 741 kg/cm2 at 180 days. OPC exhibited the highest flexural strength (86.0 kg/cm2 at 28 days), whereas SRC outperformed in tensile strength under Method I. MIP analysis revealed that water immersion curing reduced the average pore diameter of SRC to 0.0266 μm, resulting in denser concrete, making it ideal for aggressive Sulphate-rich and chloride-laden environments. The study further validates nondestructive testing methods, as pulse velocity and dynamic elastic modulus correlated well with compressive strength results, reinforcing their reliability in assessing concrete quality without destructive testing. Additionally, this research provides a practical comparison between standard curing and field-applicable curing methods, addressing real-world construction constraints where continuous water immersion is often impractical. These findings contribute to global research by offering practical insights into curing efficiency, particularly for Sulphate-resistant and blended cementitious systems. Future research should explore extended durability assessments beyond 180 days, alternative curing techniques, and machine learning-based predictive modeling to enhance curing optimization for high-performance concrete in harsh environmental conditions.
Materials of engineering and construction. Mechanics of materials
To solve the problems that the background reference frames are seriously contaminated by the foreground, and the bit rate increases suddenly incurred by the one-time transmission of the background frames, a progressive background frame generation method with image block as the basic unit was proposed for surveillance video application.An image block codebook model based on clustering was formulated.The image blocks at the same position in the video sequence were effectively clustered by using perceptual hash-based element matching.The background symbol was accurately detected by using the characteristics of the background image area.A complete background frame was produced by extracting the background blocks in different frames based on the codebook model.Experimental results demonstrate that the proposed method achieves 17.89% coding efficiency for luma component compared with standard HM16.20, and can effectively improve the quality of the produced background reference frame.Besides, the proposed method complexity meets the real-time requirements of video applications.
Shafira Putri Ananda, Muhammad Fakhrurrifqi, Divi Galih Prasetyo Putri
et al.
Rekam medis adalah catatan kesehatan pasien berdasarkan hasil pemeriksaan, pengobatan, tindakan, dan layanan yang telah diberikan kepada pasien. Beberapa instansi medis telah menggunakan sistem rekam medis elektronik atau Electronic Medical Record (EMR). Namun data rekam medis tersebut hanya dapat diakses secara lokal di tempat fasilitas kesehatan tempat ia berobat sebelumnya. Hal ini mengakibatkan keterbatasan hak akses pasien terhadap rekam medisnya jika ingin berobat ke tempat faskes lain. Berdasarkan permasalahan tersebut, maka dikembangkannya Sistem Informasi DataRawat ini agar pasien dapat mengelola dan membagikan data rekam medisnya kepada pihak yang dikehendaki. Dengan adanya informasi riwayat rekam medis pasien ini akan memudahkan tenaga medis dalam pencarian data informasi rekam medis pasien, mencatat riwayat medis dan mendiagnosa kesehatan pasien dengan cara yang lebih efisien. Sistem informasi ini dikembangkan menggunakan metode Incremental, framework Laravel, bahasa pemrograman PHP dan Javascript, dan PostgreSQL sebagai database. Hasil penelitian ini menunjukkan bahwa Pengembangan Sistem Informasi DataRawat ini dapat mengelola data seperti data rekam medis, data pasien, data rumah sakit, dan membagikan data menggunakan akses link rekam medis. Seluruh fitur yang ada pada analisis kebutuhan dapat terpenuhi dengan baik. Pada pengujian terhadap pengguna hasil menunjukkan skala berkisar 42-48 atau persentase sebesar 84%-96%. Hal ini dapat disimpulkan bahwa sistem masuk ke dalam kategori sangat layak untuk digunakan.
Computer engineering. Computer hardware, Electric apparatus and materials. Electric circuits. Electric networks
In considering projections that flooding will increase in the future years due to factors such as climate change and urbanization, the need for dependable and accurate water sensors systems is greater than ever. In this study, the performance of four different water level sensors, including ultrasonic, infrared (IR), and pressure sensors, is analyzed based on innovative characterization and comparative analysis, to determine whether or not these sensors have the ability to detect rising water levels and flash floods at an earlier stage under different conditions. During our exhaustive tests, we subjected the device to a variety of conditions, including clean and contaminated water, light and darkness, and an analogue connection to a display. When it came to monitoring water levels, the ultrasonic sensors stood out because of their remarkable precision and consistency. To address this issue, this study provides a novel and comparative examination of four water level sensors to determine which is the most effective and cost-effective in detecting floods and water level fluctuations. The IR sensor delivered accurate findings; however, it demonstrated some degree of variability throughout the course of the experiment. In addition, the results of our research show that the pressure sensor is a legitimate alternative to ultrasonic sensors. This presents a possibility that is more advantageous financially when it comes to the development of effective water level monitoring systems. The findings of this study are extremely helpful in improving the dependability and accuracy of flood detection systems and, eventually, in lessening the devastation caused by natural catastrophes.
Josiah Cherian Chekotu, Russell Goodall, David Kinahan
et al.
In this work, nitinol samples were produced via Laser Powder Bed Fusion (L-PBF) in the horizontal and vertical orientations with systematic variations in laser power, scan speed and hatch spacing parameters. Increased density was positively correlated with increased laser power, scan speed and hatch spacing for the horizontally built samples but not for the vertically built samples. A smaller difference in the average temperature within a printed layer, associated with the vertically built samples, was linked with reduced porosity and reduced porosity variability between samples. Control of the L-PBF parameters was found to allow control of the resulting part chemical composition which also directly affected phase transformation temperatures, and related phase structures. The laser process parameters were found to have a significant effect (p < 0.01) on the martensite start/finish temperature, austenite start/finish temperatures, and the total temperature span. The volumetric energy density was also found to have a direct correlation with both the cooling (r = 0.52) and heating (r = 0.53) enthalpies, which was found to be due to increased nickel evaporation. Such control of phase change properties afforded from L-PBF is important for many of the end applications for nitinol components including within the energy and precision actuation sectors.
Materials of engineering and construction. Mechanics of materials
In this article, a wideband printed half bow-tie antenna array based on a quad-mode reconfigurable feeding network for unmanned aerial vehicle (UAV) communications is presented. The proposed array consists of four printed half bow-tie antennas in the top substrate, two supports with a tapered balun, and a reflector with the reconfigurable feeding network in the bottom substrate. For UAV communications caused by wide beam coverage, the proposed reconfigurable feeding network using one single-pole-fourthrow (SP4T) and two single-pole-three-throw (SP3T) switches can adjust the phase and amplitude to the antenna element. By controlling the switches, the proposed array can be operated on four linear polarization modes. The simulated and measured results prove the proposed array reconfigurability of the main beam in four directions with 45° steps in the azimuth plane. In addition, the proposed array achieves the wide 10-dB impedance bandwidth of approximately 29.6% (1507 MHz) from 4.1 to 5.6 GHz. The peak gain and half-power beamwidths (HPBWs) on azimuth and elevation planes of the proposed array are approximately 5.9 dBi, 240°, and 99°, respectively. The overall volume size of the proposed array is 60 × 60 × 18.3 mm3 (~λ0 × λ0 × 0.3λ0 at 5.1 GHz).
Ross M. McKenzie, Jamie O. Roberts, Mohammed E. Sayed
et al.
Peristaltic conveyance can be used for the sorting and transport of delicate and nonrigid objects such as meat or soft fruit. The non‐linearity and stochastic behavior of peristaltic systems make them difficult to control. Optimizing controllers using machine learning represents a promising path to effective peristaltic control but currently, there is no suitable simulated model of a peristaltic table in which to run these optimizations. A simple, simulated model of a peristaltic conveyor that can be used for optimizing peristaltic control on a variety of peristaltic tables is presented. This simulator is demonstrated through a limited control problem evaluated on our real‐world system that is built for peristaltic conveyance. This simulator is available as the python package PeriSim so that it can be used by the robotics community for peristaltic control development.
Computer engineering. Computer hardware, Control engineering systems. Automatic machinery (General)
Optimization method has been widely acknowledged as an effective approach to design engineering structures, and yet few studies adopt this method to design cellular materials. Here, we firstly adopted a Kriging assisted Multi-objective Genetic Algorithm to guideline the design of octet-truss (OCT) cellular materials with the maximum specific modulus. Subsequently, additional struts were artificially introduced into the optimized OCT to further mechanically reinforce performances. All the cellular materials were precisely fabricated using a Stereolithography 3D printing technique. By reasonably optimizing the sizes of OCT, the optimized OCT with a 1.112 mm diameter and 8.282 mm cell length was achieved, which displays a superior modulus-to-mass ratio. The highest modulus and strength of as-designed cellular materials achieved 34.12 MPa and 2.64 MPa, reinforced by ~3.11 and 4.81 times, respectively. Additionally, the absorbed energy efficiencies of them improved from 74.75% to 90.80%, which are significantly higher than other cellular materials. By in situ tests and fracture analyses, the high recoverability is attributed to the comprehensive effect of net-shaped architecture and elastic-plastic deformation. Keywords: Cellular materials, Optimization design, 3D printing technique, In situ tests, Deformation mechanism, Recoverability
Materials of engineering and construction. Mechanics of materials
Ala Gouissem, Ridha Hamila, Naofal Al-dhahir
et al.
Cooperative communication has attracted significant attention in the last decade due to its ability to increase the spatial diversity order with only single-antenna nodes. However, most of the techniques in the literature are not suitable for large cooperative networks such as device-to-device and wireless sensor networks that are composed of a massive number of active devices, which significantly increases the relay selection complexity. Therefore, to solve this problem and enhance the spatial and frequency diversity orders of large amplify and forward cooperative communication networks, in this paper, we develop three multiple relay selection and distributed beamforming techniques that exploit sparse signal recovery theory to process the subcarriers using the low complexity orthogonal matching pursuit algorithm (OMP). In particular, by separating all the subcarriers or some subcarrier groups from each other and by optimizing the selection and beamforming vector(s) using OMP algorithm, a higher level of frequency diversity can be achieved. This increased diversity order allows the proposed techniques to outperform existing techniques in terms of bit error rate at a lower computation complexity. A detailed performance-complexity tradeoff, as well as Monte Carlo simulations, are presented to quantify the performance and efficiency of the proposed techniques.
In the last year, with a huge usage of wireless enforcement and where nearly everything which was controlled by humans is being automated by using robots. In this paper a control system of the mobile robotic arm was built by using a PS2 joystick and the microcontroller (Arduino UNO) and sends the command by the master Bluetooth (HC-05) that represents the transmitter part. Where the receiver receives the data by the slave Bluetooth (HC_05) to generate the specific motion by take the command from Arduino UNO. The purpose of this paper is to design and implement a mobile arm robot for dangerous and difficult places that humans can't reach it and make the specific tasks.
Engineering machinery, tools, and implements, Mechanics of engineering. Applied mechanics
Residual stress has significant influence on the performance of mechanical components, and the nondestructive estimation of residual stress is always a difficult problem. This study applies the relative nonlinear coefficient of critical refraction longitudinal (LCR) wave to nondestructively characterize the stress state of materials; the feasibility of residual stress estimation using the nonlinear property of LCR wave is verified. The nonlinear ultrasonic measurements based on LCR wave are conducted on components with known stress state to calculate the relative nonlinear coefficient. Experimental results indicate that the relative nonlinear coefficient monotonically increases with prestress and the increment of relative nonlinear coefficient is about 80%, while the wave velocity only decreases about 0.2%. The sensitivity of the relative nonlinear coefficient for stress is much higher than wave velocity. Furthermore, the dependence between the relative nonlinear coefficient and deformation state of components is found. The stress detection resolution based on the nonlinear property of LCR wave is 10 MPa, which has higher resolution than wave velocity. These results demonstrate that the nonlinear property of LCR wave is more suitable for stress characterization than wave velocity, and this quantitative information could be used for residual stress estimation.
Materials of engineering and construction. Mechanics of materials
Due to the existence of multiple views in many real-world data sets, multi-view clustering is increasingly popular. Many approaches have been investigated, among which the subspace clustering methods finding the underlying subspaces of data have been developed recently. Although the subspace-based multi-view methods can achieve promising performance, the shared subspace information has not been fully utilized. To address this problem, a novel multi-view clustering model by simultaneously learning shared subspace and affinity matrix is proposed. In our method, a shared subspace is learned to preserve the effective consensus information of all views. Then, a subspace-based affinity matrix with adaptive neighbors is learned to assign the most suitable cluster to each data point. An iterative strategy is developed for solving this problem. Moreover, experiments on four benchmark data sets demonstrate that our algorithm outperforms other state-of-the-art algorithms.
A novel MUSIC-type algorithm is derived in this paper for the direction of departure (DOD) and direction of arrival (DOA) estimation in a bistatic MIMO radar. Through rearranging the received signal matrix, we illustrate that the DOD and the DOA can be separately estimated. Compared with conventional MUSIC-type algorithms, the proposed separate MUSIC algorithm can avoid the interference between DOD and DOA estimations effectively. Therefore, it is expected to give a better angle estimation performance and have a much lower computational complexity. Meanwhile, we demonstrate that our method is also effective for coherent targets in MIMO radar. Simulation results verify the efficiency of the proposed method, particularly when the signal-to-noise ratio (SNR) is low and/or the number of snapshots is small.
Math model of heat transfer during solidification of Φ400 mm concasting round bloom of steel 34Mn5V has been established and surface temperature values at controlling location of each secondary zone calculated by the model showed no difference to that measured at production ground. It is obtained with calculation by model that the effect of liquid superheating extent on surface temperature of bloom is minor but the effect of casting speed and secondary cooling intensity on temperature of bloom is larger. Production practice showed that the automatic control secondary cooling system met the requirements of industrial concasting Φ400 mm round bloom with cast speed 0. 4 -0. 6 m/min to get quality cast bloom.
Materials of engineering and construction. Mechanics of materials, Technology
The paper presents two methods to analyzethe electric circuits using the flow-graphs and thebond-graphs studying the differences between thesemethods.As it can be noticed, the two methods are totallydifferent; their common point being Mason’s rule thatis applied in both cases but it is applied differently foreach type of graphs.