Applied Sciences

17 pages, 3500 KiB

Open AccessArticle

Study on Safety Mining Technology of Gob in Stopping Face by Replacing Pressure Equalization with Gob Pumping—A Case Study of Sitai Mine

by Yun Xu, Guofu Li, Chenglin Huang, Jie Wang, Liangliang Liu and Hao Shao

Appl. Sci. 2024, 14(13), 5965; https://doi.org/10.3390/app14135965 - 8 Jul 2024

Viewed by 572

Abstract

Gas control in the upper corner of the natural coal mining face with high gas is always a difficult problem that troubles the safe production of the working face. Among them, a high gas-prone natural coal mining face with ground air leakage is [...] Read more.

Gas control in the upper corner of the natural coal mining face with high gas is always a difficult problem that troubles the safe production of the working face. Among them, a high gas-prone natural coal mining face with ground air leakage is more likely to cause gas and CO to exceed limits in the corner of the working surface and is difficult to control. The traditional treatment methods often have some problems; for example, it is easy to increase air leakage in the gob with the method of gas extraction in the gob, which is not conducive to the prevention and control of spontaneous combustion of coal in the gob. At present, the more effective method is the pressure-equalization method. However, the pressure-equalization measures need to establish a complex pressure-equalization system, and close cooperation between the systems is required; once the system power fails or equipment failure occurs, the pressure-equalization state changes randomly, and it is easy to cause gas over-limits and other faults. Therefore, this paper presents a new method to control gas in the gob of a coal seam by pumping the gob of the upper-adjacent layer, using the negative pressure of pumping, and balancing the negative pressure of the upper-adjacent layer and the gob of the coal seam to form a new pressure-equalization relationship. This method can prevent the toxic and harmful gases in the goaf of the upper-adjacent layer from escaping into the passageway of the gob of the local coal seam, reduce the air leakage in the goaf, and benefit the gas control and spontaneous coal combustion prevention in the goaf. Full article

(This article belongs to the Section Earth Sciences)

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11 pages, 22608 KiB

Open AccessArticle

Automatic Definition of Traffic Analysis Zones Based on Big Data

by Viktor Nagy and Balázs Horváth

Appl. Sci. 2024, 14(13), 5964; https://doi.org/10.3390/app14135964 - 8 Jul 2024

Viewed by 429

Abstract

The planning process for any transport system can be considered complete if it is accompanied by a modeling system to evaluate the intervention. The study area should always be divided into traffic zones. Correct zoning is the key to any transport system study. [...] Read more.

The planning process for any transport system can be considered complete if it is accompanied by a modeling system to evaluate the intervention. The study area should always be divided into traffic zones. Correct zoning is the key to any transport system study. The basic principles of zone creation require a thorough understanding of the area and local traffic conditions. However, this is not always a given, especially if a universally applicable assessment system is to be developed. This has led to the need to develop an algorithm that is able to provide an estimate for the definition of traffic zones based on some automatically observable or measurable phenomena or sequence of events. The aim of this research is to identify the observable events that are suitable for characterizing the area, so that an automatic zone definition procedure can be developed based on these. In this paper, automatic WAZE-generated congestion data were processed in a selected district of Budapest. During the processing, the area was divided into a grid network and time series were developed that show the traffic flow on the grid network as a function of the congestion level. The area subdivisions were then clustered using spectral clustering to create spatially distinct districts with identical traffic behavior. Full article

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22 pages, 2401 KiB

Open AccessSystematic Review

Chewing Bite Wafers versus Conventional Analgesic Drugs to Relieve Self-Reported Pain Associated with Fixed Orthodontic Appliances: A Systematic Review and Meta-Analysis

by Luay Jabr, Maryam Altuhafy, Abdul Basir Barmak, Paul Emile Rossouw and Dimitrios Michelogiannakis

Appl. Sci. 2024, 14(13), 5963; https://doi.org/10.3390/app14135963 - 8 Jul 2024

Viewed by 382

Abstract

(1) Objectives: To estimate the impact of chewing bite wafers in reducing pain associated with fixed orthodontic treatment (OT) compared with conventional analgesic drugs (CADs) (Ibuprofen or Acetaminophen). (2) Materials and methods: Unrestricted and manual searching was achieved up to November 2023 and [...] Read more.

(1) Objectives: To estimate the impact of chewing bite wafers in reducing pain associated with fixed orthodontic treatment (OT) compared with conventional analgesic drugs (CADs) (Ibuprofen or Acetaminophen). (2) Materials and methods: Unrestricted and manual searching was achieved up to November 2023 and PRISMA guidelines were followed. Randomized controlled trials (RCTs) were included. Meta-analyses were conducted using a random-effects model. The available evidence quality was considered using the GRADE approach. (3) Results: Seven RCTs were included. Five RCTs used the Visual Analog Scale for self-reported pain assessment, while two RCTs used the Numeric Rating Scale. Four RCTs had a high RoB, and three RCTs had a moderate RoB. Separate meta-analyses were performed by pooling quantitative data from two RCTs that compared self-reported orthodontic pain between the bite wafer and Ibuprofen groups and three RCTs that compared the bite wafer and Acetaminophen groups for the different timepoints after orthodontic treatment. None of the timepoints individually indicated a significant difference in pain scores between the bite wafer and control groups, except on day 3, indicating significantly lower pain scores in the bite wafer versus the Acetaminophen groups. The overall level of evidence was very low. (4) Conclusions: Chewing bite wafers is possibly a useful option for CADs to relieve pain during early fixed OT. Full article

(This article belongs to the Special Issue Orthodontic Treatment: Current State and Future Possibilities)

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13 pages, 4739 KiB

Open AccessArticle

Construction Technology and Service Performance of Waterproof Curtain for Foundation Pit in Large-Particle Pebble Gravel Layer of Yangtze River Floodplain

by Wen Xu, Bo Liu and Jin Wu

Appl. Sci. 2024, 14(13), 5962; https://doi.org/10.3390/app14135962 - 8 Jul 2024

Viewed by 385

Abstract

A foundation pit is constructed in the floodplain of Yangtze River, and a deep and thick layer of large-particle pebble gravel exists below the base slab, thus forming a connected supply channel with the adjacent Yangtze River. The large water volume, high water [...] Read more.

A foundation pit is constructed in the floodplain of Yangtze River, and a deep and thick layer of large-particle pebble gravel exists below the base slab, thus forming a connected supply channel with the adjacent Yangtze River. The large water volume, high water pressure, and strong permeability of this layer bring great risks to the foundation pit construction. In view of the fact that conventional waterproof curtain construction technologies such as the deep mixing column and high-pressure jet grouting column cannot meet the engineering requirements under these kinds of geological and environmental conditions, a new waterproof curtain construction technology that combines the trenching technology of the diaphragm wall with the TRD (Trench cutting Remixing Deep wall) technology is proposed, i.e., the trenching-and-replacing-style TRD technology, as well as the construction process of this technology, is presented. After the waterproof curtain is built using the proposed technology, the strength, integrity, uniformity, and service performance of the waterproof curtain wall are tested and evaluated by the comprehensive methods of coring, borehole television imaging, resistivity CT, and a group well pumping test. The results show that the proposed technology overcomes the adverse effects of underlying large-particle pebble gravel layer, and the waterproof curtain built by it effectively cuts off the hydraulic connection inside and outside the pit. The technical proposal can provide useful references for similar projects. Full article

(This article belongs to the Special Issue Foundation Treatment in Civil Engineering)

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15 pages, 5972 KiB

Open AccessArticle

Identifying Goalkeeper Movement Timing from Single-Camera Broadcast Footage through Pose Estimation: A Pilot Study

by Chethan Reddy and Woohyoung Jeon

Appl. Sci. 2024, 14(13), 5961; https://doi.org/10.3390/app14135961 - 8 Jul 2024

Viewed by 370

Abstract

This study explores how open-source pose estimation can be utilized to identify goalkeeper dive initiation during soccer penalty kicks. The purpose of this study is to provide an accessible, low-cost heuristic methodology for identifying goalkeeper dive initiation. This study uses single-camera broadcast footage [...] Read more.

This study explores how open-source pose estimation can be utilized to identify goalkeeper dive initiation during soccer penalty kicks. The purpose of this study is to provide an accessible, low-cost heuristic methodology for identifying goalkeeper dive initiation. This study uses single-camera broadcast footage (1080 p resolution, 50 frames per second) of all 41 penalty shootout kicks attempted during the 2022 FIFA Men’s World Cup. We isolated each penalty kick and recorded the frames of goalkeeper dive initiation and flight. We then identified goalposts to create a homography matrix to account for camera movement and identified the goalkeeper’s skeletal keypoints through pose estimation. From these keypoints, we derived frontal plane kinematics for the torso and legs. We identified local extrema for each kinematic variable and isolated the last observed extrema prior to goalkeeper flight for each variable. Using OLS regression, we found that the last local extremum of the goalkeeper centroid’s y-value was the strongest predictor of labeled commitment to the dive side, with an R2 of 0.998 and a p-value of 0.00. The results of this research are preliminary but demonstrate the promise of pose estimation in identifying sport-specific action timing during live game play using a single camera. Full article

(This article belongs to the Section Applied Biosciences and Bioengineering)

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36 pages, 1602 KiB

Open AccessArticle

DTAG: A Methodology for Aggregating Digital Twins Using the WoTDT Ontology

by Salvador González-Gerpe, María Poveda-Villalón and Raúl García-Castro

Appl. Sci. 2024, 14(13), 5960; https://doi.org/10.3390/app14135960 - 8 Jul 2024

Viewed by 371

Abstract

The advancement of digital twins (DTws) has been instrumental in various scientific and industrial domains, facilitating real-time monitoring, analysis, and optimisation of complex systems. However, it remains difficult to describe precisely the architectural models and their characteristics of DTws and the aggregation of [...] Read more.

The advancement of digital twins (DTws) has been instrumental in various scientific and industrial domains, facilitating real-time monitoring, analysis, and optimisation of complex systems. However, it remains difficult to describe precisely the architectural models and their characteristics of DTws and the aggregation of lower-level DTws to higher-level DTws. This article introduces two contributions with the goal of addressing challenges in describing DTws architectures and aggregating DTws. Firstly, it presents the development of “WoTDT” (WoT digital twin) ontology, an extension of the W3C Web of Things descriptions ontology, designed to semantically describe the five-dimensional model architecture of DTws. This ontology enhances data interoperability and accessibility across dimensions, promoting a deeper understanding of DTws. Secondly, it introduces the “DTAG” (digital twin aggregation) methodology for aggregating multiple DTws into an unified DTw aggregate (DTwA). This methodology considers whether the DTws contain semantics or not and employs the WoTDT ontology to conceptualise the architecture and features of the resulting DTwA. Finally, an example of WoTDT ontology together with the DTAG methodology is shown in the context of the European H2020 construction-related project COGITO. Full article

(This article belongs to the Special Issue Advances in Ontology and the Semantic Web)

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14 pages, 675 KiB

Open AccessArticle

Machine Learning Models to Enhance the Berlin Questionnaire Detection of Obstructive Sleep Apnea in at-Risk Patients

by Luana Conte, Giorgio De Nunzio, Francesco Giombi, Roberto Lupo, Caterina Arigliani, Federico Leone, Fabrizio Salamanca, Cosimo Petrelli, Paola Angelelli, Luigi De Benedetto and Michele Arigliani

Appl. Sci. 2024, 14(13), 5959; https://doi.org/10.3390/app14135959 - 8 Jul 2024

Viewed by 369

Abstract

The Berlin questionnaire (BQ), with its ten questions, stands out as one of the simplest and most widely implemented non-invasive screening tools for detecting individuals at a high risk of Obstructive Sleep Apnea (OSA), a still underdiagnosed syndrome characterized by the partial or [...] Read more.

The Berlin questionnaire (BQ), with its ten questions, stands out as one of the simplest and most widely implemented non-invasive screening tools for detecting individuals at a high risk of Obstructive Sleep Apnea (OSA), a still underdiagnosed syndrome characterized by the partial or complete obstruction of the upper airways during sleep. The main aim of this study was to enhance the diagnostic accuracy of the BQ through Machine Learning (ML) techniques. A ML classifier (hereafter, ML-10) was trained using the ten questions of the standard BQ. Another ML model (ML-2) was trained using a simplified variant of the BQ, BQ-2, which comprises only two questions out of the total ten. A 10-fold cross validation scheme was employed. Ground truth was provided by the Apnea–Hypopnea Index (AHI) measured by Home Sleep Apnea Testing. The model performance was determined by comparing ML-10 and ML-2 with the standard BQ in the Receiver Operating Characteristic (ROC) space and using metrics such as the Area Under the Curve (AUC), sensitivity, specificity, and accuracy. Both ML-10 and ML-2 demonstrated superior performance in predicting the risk of OSA compared to the standard BQ and were also capable of classifying OSA with two different AHI thresholds (AHI ≥ 15, AHI ≥ 30) that are typically used in clinical practice. This study underscores the importance of integrating ML techniques for early OSA detection, suggesting a direction for future research to improve diagnostic processes and patient outcomes in sleep medicine with minimal effort. Full article

(This article belongs to the Special Issue Artificial Intelligence Applications in Healthcare and Precision Medicine)

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22 pages, 1214 KiB

Open AccessReview

Retrofitting of Steel Structures with CFRP: Literature Review and Research Needs

by Mohamadreza Delzendeh Moghadam, Abbas Fathi and Omar Chaallal

Appl. Sci. 2024, 14(13), 5958; https://doi.org/10.3390/app14135958 - 8 Jul 2024

Viewed by 405

Abstract

The application of the externally bonded (EB) carbon fiber-reinforced polymer (CFRP) technique for retrofitting steel elements offers significant advantages over the conventional method. The high strength-to-weight ratio and corrosion resistance of CFRP materials have made them a viable alternative for retrofitting steel structures. [...] Read more.

The application of the externally bonded (EB) carbon fiber-reinforced polymer (CFRP) technique for retrofitting steel elements offers significant advantages over the conventional method. The high strength-to-weight ratio and corrosion resistance of CFRP materials have made them a viable alternative for retrofitting steel structures. This paper covers a wide range of aspects discussed in the research investigations to date on CFRP bonded steel elements and provides a critical review of the topic under both static and fatigue loading conditions. In the end, research needs and recommendations are presented in this respect. Full article

(This article belongs to the Special Issue Advances in Bridge Design and Construction: Technologies and Applications)

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13 pages, 5639 KiB

Open AccessCase Report

Full Digital Workflow for Aesthetic Rehabilitation of the Upper Teeth: A Case Report

by Gilbert Jorquera, Louis Hardan, Rim Bourgi, David Arias, Carlos Enrique Cuevas-Suárez, Krystyna Pietrzycka and Monika Lukomska-Szymanska

Appl. Sci. 2024, 14(13), 5957; https://doi.org/10.3390/app14135957 - 8 Jul 2024

Viewed by 455

Abstract

The present case report presents a digital workflow for designing an aesthetic rehabilitation of the upper anterior teeth in an adult male. The patient suffered from a gummy smile resulting from an unfavorable ratio between upper lip length and gingiva/tooth display. In addition, [...] Read more.

The present case report presents a digital workflow for designing an aesthetic rehabilitation of the upper anterior teeth in an adult male. The patient suffered from a gummy smile resulting from an unfavorable ratio between upper lip length and gingiva/tooth display. In addition, the tooth shapes, color, and position were not accepted by the patient. The treatment planning included gingivectomy based on a digitally designed PMMA guide performed using a soft tissue SOGA laser (Shenzhen Soga Technology Co., Ltd., Shenzhen, China). The preparation was guided by the plastic guides for preparation control created digitally in Exocad software (Rijeka 3.1. Darmstadt, Germany) and printed in three-dimensional plastic. Next, both arches and maximum intercuspation were scanned. The milled lithium disilicate veneers were manufactured using CAD-computer-aided manufacturing (CAM) equipment. The restorations were cemented using a translucent light-cure resin cement (RelyX Universal, 3M ESPE, St. Paul, MN, USA). Next, occlusion adjustment and polishing were executed. Based on the present case report, it can be assumed that the application of digital techniques allows us to achieve an aesthetic and functional result with reduced work time and errors. Emphasizing the clinical impact, these methods enhance patient satisfaction and treatment accuracy in intricate aesthetic rehabilitations. Full article

(This article belongs to the Special Issue Advancements and Updates in Digital Dentistry)

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23 pages, 26729 KiB

Open AccessArticle

A Parameter-Driven Methodology of Wheel Flat Modeling for Wheel–Rail Impact Dynamics

by Guangwei Zhao, Nan Li, Yuxin Sun and Changxin Chi

Appl. Sci. 2024, 14(13), 5956; https://doi.org/10.3390/app14135956 - 8 Jul 2024

Viewed by 392

Abstract

A wheel flat is a typical wheel defect that significantly impacts the wheel–rail system, posing substantial challenges to vehicle operation safety. In the existing literature, the wheel flat plane model does not account for the contribution of the width direction to the impact [...] Read more.

A wheel flat is a typical wheel defect that significantly impacts the wheel–rail system, posing substantial challenges to vehicle operation safety. In the existing literature, the wheel flat plane model does not account for the contribution of the width direction to the impact response and thus cannot accurately reveal the wheel–rail contact state with a flat. This paper systematically proposes a three-dimensional analytical model that considers multiple worn stages and constructs a spatial complex surface reconstruction model for flats based on NURBS technology. A vehicle–track coupled dynamics model, considering the geometry of the flat, is established to investigate the effects of flat geometry on the wheel–rail impact response and contact relationship in detail. The results show that in the subcritical regime, the wear degree of the flat predominantly affects the impact force, while in the transcritical regime, both the wear degree and velocity together determine the magnitude of the wheel–rail impact force. As the wear degree increases, the moment of wheel lateral jump occurs earlier. The spatial modeling method for flats proposed in this paper offers a novel technical approach for accurately simulating the dynamic behavior of wheel–rail contact when a flat is present. Full article

(This article belongs to the Topic Vehicle Dynamics and Control)

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21 pages, 5233 KiB

Open AccessArticle

Three Novel Artificial Neural Network Architectures Based on Convolutional Neural Networks for the Spatio-Temporal Processing of Solar Forecasting Data

by Llinet Benavides Cesar, Miguel-Ángel Manso-Callejo and Calimanut-Ionut Cira

Appl. Sci. 2024, 14(13), 5955; https://doi.org/10.3390/app14135955 - 8 Jul 2024

Viewed by 514

Abstract

In this work, three new convolutional neural network models—spatio-temporal convolutional neural network versions 1 and 2 (ST_CNN_v1 and ST_CNN_v2), and the spatio-temporal dilated convolutional neural network (ST_Dilated_CNN)—are proposed for solar forecasting and processing global horizontal irradiance (GHI) data enriched with meteorological and astronomical [...] Read more.

In this work, three new convolutional neural network models—spatio-temporal convolutional neural network versions 1 and 2 (ST_CNN_v1 and ST_CNN_v2), and the spatio-temporal dilated convolutional neural network (ST_Dilated_CNN)—are proposed for solar forecasting and processing global horizontal irradiance (GHI) data enriched with meteorological and astronomical variables. A comparative analysis of the proposed models with two traditional benchmark models shows that the proposed ST_Dilated_CNN model outperforms the rest in capturing long-range dependencies, achieving a mean absolute error of 31.12 W/m², a mean squared error of 54.07 W/m², and a forecast skill of 37.21%. The statistical analysis carried out on the test set suggested highly significant differences in performance (p-values lower than 0.001 for all metrics in all the considered scenarios), with the model with the lowest variability in performance being ST_CNN_v2. The statistical tests applied confirmed the robustness and reliability of the proposed models under different conditions. In addition, this work highlights the significant influence of astronomical variables on prediction performance. The study also highlights the intricate relationship between the proposed models and meteorological and astronomical input characteristics, providing important insights into the field of solar prediction and reaffirming the need for further research into variability factors that affect the performance of models. Full article

(This article belongs to the Special Issue Advanced Forecasting Techniques and Methods for Energy Systems)

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14 pages, 6785 KiB

Open AccessArticle

Exoland Simulator, a Laboratory Device for Reflectance Spectral Analyses of Planetary Soil Analogs: Design and Simulation

by Marco Dionigi, Silvia Logozzo, Maria Cristina Valigi, Paola Comodi, Alessandro Pisello, Diego Perugini and Maximiliano Fastelli

Appl. Sci. 2024, 14(13), 5954; https://doi.org/10.3390/app14135954 - 8 Jul 2024

Viewed by 330

Abstract

In planetary science, visible (Vis) and near-infrared (NIR) reflectance spectra allow deciphering the chemical/mineralogical composition of celestial bodies’ surfaces by comparison between remotely acquired data and laboratory references. This paper presents the design of an automated test rig named Exoland Simulator equipped with [...] Read more.

In planetary science, visible (Vis) and near-infrared (NIR) reflectance spectra allow deciphering the chemical/mineralogical composition of celestial bodies’ surfaces by comparison between remotely acquired data and laboratory references. This paper presents the design of an automated test rig named Exoland Simulator equipped with two reflectance spectrometers covering the 0.38–2.2 µm range. It is designed to collect data of natural/synthetic rocks and minerals prepared in the laboratory that simulate the composition of planetary surfaces. The structure of the test rig is conceived as a Cartesian robot to automatize the acquisition. The test rig is also tested by simulating some project trajectories, and results are presented in terms of its ability to reproduce the programmed trajectories. Furthermore, preliminary spectral data are shown to demonstrate how the soil analogs’ spectra could allow an accurate remote identification of materials, enabling the creation of libraries to study the effect of multiple chemical–physical component variations on individual spectral bands. Despite the primary scope of Exoland, it can be advantageously used also for tribological purposes, to correlate the wear behavior of soils and materials with their composition by also analyzing the wear scars. Full article

(This article belongs to the Section Surface Sciences and Technology)

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18 pages, 8143 KiB

Open AccessArticle

Fuzzy Classification of the Maturity of the Orange (Citrus × sinensis) Using the Citrus Color Index (CCI)

by Marcos J. Villaseñor-Aguilar, Miroslava Cano-Lara, Adolfo R. Lopez, Horacio Rostro-Gonzalez, José Alfredo Padilla-Medina and Alejandro Israel Barranco-Gutiérrez

Appl. Sci. 2024, 14(13), 5953; https://doi.org/10.3390/app14135953 - 8 Jul 2024

Viewed by 364

Abstract

The orange (Citrus sinensis) is a fruit of the Citrus genus, which is part of the Rutaceae family. The orange has gained considerable importance due to its extensive range of applications, including the production of juices, jams, sweets, and extracts. The [...] Read more.

The orange (Citrus sinensis) is a fruit of the Citrus genus, which is part of the Rutaceae family. The orange has gained considerable importance due to its extensive range of applications, including the production of juices, jams, sweets, and extracts. The consumption of oranges confers several nutritional benefits, including flavonoids, vitamin C, potassium, beta-carotene, and dietary fiber. It is crucial to acknowledge that the primary quality criterion employed by consumers and producers is maturity, which is correlated with the visual quality associated with the color of the epicarp. This study proposes the implementation of a computer vision system that estimates the degree of ripeness of oranges Valencia using fuzzy logic (FL); the soluble solids content was determined by refractometry, while the firmness of the fruit was evaluated through the fruit firmness test. The proposed method was divided into five distinct steps. The initial stage involved the acquisition of RGB images. The second stage presents the segmentation of the fruit, which entails the removal of extraneous noise and backgrounds. The third and fourth steps involve determining the centroid of the fruit, and five regions of interest were obtained in the centroid of the fruit of the Citrus Color Index (CII), ranging from 3 × 3 to 11 × 11 pixels. Finally, in the fifth step, a model was created to estimate maturity, °Brix, and firmness using Matlab 2024 and the Fuzzy Logic Designer and Neuro-Fuzzy Designer applications. Consequently, a statistically significant correlation was established between maturity, degree Brix, and firmness, with a value greater than 0.9, using the Citrus Color Index (CII), which reflects the physical–chemical changes that occur in the orange. Full article

(This article belongs to the Special Issue Advances in Machine Vision for Industry and Agriculture)

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23 pages, 6007 KiB

Open AccessReview

A Critical Review of the Status of Current Greenhouse Technology in China and Development Prospects

by Bin Guo, Biao Zhou, Zhiming Zhang, Kaidi Li, Jianye Wang, Jiufa Chen and George Papadakis

Appl. Sci. 2024, 14(13), 5952; https://doi.org/10.3390/app14135952 - 8 Jul 2024

Viewed by 524

Abstract

China’s greenhouse industry has undergone thousands of years of development history, although the development of modern greenhouses arrived late. After decades of development in China, its greenhouse industry is at the global forefront. China’s greenhouse industry is experiencing rapid development, transformation, and upgrading. [...] Read more.

China’s greenhouse industry has undergone thousands of years of development history, although the development of modern greenhouses arrived late. After decades of development in China, its greenhouse industry is at the global forefront. China’s greenhouse industry is experiencing rapid development, transformation, and upgrading. China ranks first in the world in terms of the greenhouse industry. These greenhouses are mainly used for vegetable cultivation, playing an important role in the utilization of agricultural resources and food production. In 2023, the cumulative area of greenhouses nationwide was 1835.87 million ha. In this paper, we present the latest developments in the greenhouse sector. More specifically, we present an overview of the development of the greenhouse market, greenhouse production, the greenhouse industry, and technology development. Current problems are underpinned, development opportunities and prospects are analyzed, and measures and specific proposals are detailed for the technological development of the greenhouse sector, both for increasing product quantity and quality. Full article

(This article belongs to the Section Agricultural Science and Technology)

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12 pages, 1891 KiB

Open AccessArticle

Possible Development of Efficient Local Energy Community on the Example of the City of Žilina in Slovakia

by Peter Durcansky, Branislav Zvada and Radovan Nosek

Appl. Sci. 2024, 14(13), 5951; https://doi.org/10.3390/app14135951 - 8 Jul 2024

Viewed by 325

Abstract

Reducing the energy demand in the housing sector is one of the current topics in the EU. Slovakia, as an EU member, is also trying to lower the dependence on the import of energy raw materials used for heating. While new buildings reflect [...] Read more.

Reducing the energy demand in the housing sector is one of the current topics in the EU. Slovakia, as an EU member, is also trying to lower the dependence on the import of energy raw materials used for heating. While new buildings reflect the technical requirements of applicable standards, buildings built in the past usually do not meet any technical requirements. The basis of efficient operation is not only satisfactory building structures, but also technological equipment of the buildings. The heating system is often in an unsatisfactory state, and an outdated heat source disproportionately reduces the overall efficiency of energy conversion. Complex restoration is, therefore, in most cases, necessary and often financially costly. The presented article analyzes the current state of housing stock in the example of a selected city district. In the next step, the current state and energy consumption are identified. Subsequently, needed retrofit measures are identified and the possibilities of renewal are analyzed. The use of RES in buildings is proposed, while selected city districts could create an independent energy community. The main goal of this article is to show the necessary steps to achieve efficient energy use and, using the example of a Zilina City district, show the possible benefits of such community creation in Slovakia. The article also discusses the correlation between the number of sunny days and possible energy generation in winter months. Full article

(This article belongs to the Special Issue Advances in the Sustainability and Energy Efficiency of Buildings)

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21 pages, 478 KiB

Open AccessArticle

Towards Model-Driven Explainable Artificial Intelligence: Function Identification with Grammatical Evolution

by Dominik Sepioło and Antoni Ligęza

Appl. Sci. 2024, 14(13), 5950; https://doi.org/10.3390/app14135950 - 8 Jul 2024

Viewed by 509

Abstract

Machine learning is a well-matured discipline, and exploration of datasets can be performed in an efficient way, leading to accurate and operational prediction and decision models. On the other hand, most methods tend to produce black-box-type models, which can be considered a serious [...] Read more.

Machine learning is a well-matured discipline, and exploration of datasets can be performed in an efficient way, leading to accurate and operational prediction and decision models. On the other hand, most methods tend to produce black-box-type models, which can be considered a serious drawback. This is so, since in case of numerous practical applications, it is also required to justify, explain, and uncover the inner decision mechanism so that an in-depth understanding of the causal and functional dependencies becomes possible and some responsibility for the decision can be considered. This paper addresses the critical need for model-driven eXplainable Artificial Intelligence (XAI) by exploring the limitations inherent in existing explanatory mechanisms, such as LIME or SHAP, which rely solely on input data. This seems to be an intrinsic limitation and a conceptual error, as no expert domain knowledge can come into play, and no analytical models of the phenomena under investigation are created. In order to deal with this issue, this paper puts forward the idea of building open, white-box explanatory models. To do that, we propose employing grammatical evolution tools combined with expert domain knowledge. The results demonstrate that the developed models can effectively explain the structure and behavior of decision models in terms of components, connections, causality, and simple functional dependencies. Full article

(This article belongs to the Section Computing and Artificial Intelligence)

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17 pages, 760 KiB

Open AccessArticle

A Galerkin Finite Element Method for the Reconstruction of a Time-Dependent Convection Coefficient and Source in a 1D Model of Magnetohydrodynamics

by Miglena N. Koleva and Lubin G. Vulkov

Appl. Sci. 2024, 14(13), 5949; https://doi.org/10.3390/app14135949 - 8 Jul 2024

Viewed by 319

Abstract

The mathematical analysis of viscous magnetohydrodynamics (MHD) models is of great interest in recent years. In this paper, a finite element Galerkin method is employed for the estimation of an unknown time-dependent convection coefficient and source in a 1D magnetohydrodynamics flow system. In [...] Read more.

The mathematical analysis of viscous magnetohydrodynamics (MHD) models is of great interest in recent years. In this paper, a finite element Galerkin method is employed for the estimation of an unknown time-dependent convection coefficient and source in a 1D magnetohydrodynamics flow system. In this inverse problem, two integral observations are posed and used to transform the inverse problem to a non-classical direct problem with a non-local parabolic operator. Then, the non-classical strongly coupled parabolic system is studied in various settings. The equivalence of the inverse problem (IP) and the direct one are proven. The Galerkin procedure is analyzed to proove the existence and uniqueness of the solution. The finite element method (FEM) has been developed for the solution of the variational problem. Test examples are discussed. Full article

(This article belongs to the Special Issue Advanced Finite Element Method and Its Applications)

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19 pages, 3154 KiB

Open AccessArticle

Multi-Factor Highway Freight Volume Prediction Based on Backpropagation Neural Network

by Yanshuang Zhang, Caixia Tian, Baohua Guo, Meixia Wang, Zhezhe Zhang and Kgaugelo Morobeni

Appl. Sci. 2024, 14(13), 5948; https://doi.org/10.3390/app14135948 - 8 Jul 2024

Viewed by 381

Abstract

With the development of the times, the traditional single-factor time series prediction cannot meet the needs of actual prediction, and it is necessary to comprehensively consider the influence of various variables on prediction results. Therefore, we use MATLAB R2022a to predict the multi-factor [...] Read more.

With the development of the times, the traditional single-factor time series prediction cannot meet the needs of actual prediction, and it is necessary to comprehensively consider the influence of various variables on prediction results. Therefore, we use MATLAB R2022a to predict the multi-factor highway freight volume. According to the relevant data of highway freight volume in Chinese history, the BP neural network prediction model of highway freight volume is established, and the model is coded and calculated in the MATLAB software environment. Through repeated training of the data, the predicted value is finally obtained. The results show that the prediction accuracy of the BP neural network model based on multi-factor prediction is very high. Through the example analysis of China’s highway freight volume, the original data are accurately fitted, and the validity of the highway freight volume prediction model based on BP neural network is proved. Through the prediction of freight volume, the investment in infrastructure construction is improved to promote the development of transportation industry and the progress of social economy. Full article

(This article belongs to the Section Transportation and Future Mobility)

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27 pages, 8726 KiB

Open AccessArticle

Topology Optimization of Anisotropic Materials with Smooth Fiber Orientation

by Shaofei Jiang, Chaofan Shang, Jiquan Li, Bing Yi and Xiang Peng

Appl. Sci. 2024, 14(13), 5947; https://doi.org/10.3390/app14135947 - 8 Jul 2024

Viewed by 395

Abstract

In the concurrent optimization of topology and fiber orientation, the design of smooth fiber helps to maintain the stability of numerical calculation and the compatibility of the manufacturing process. However, the improvement of fiber continuity is often accompanied by a significant decrease in [...] Read more.

In the concurrent optimization of topology and fiber orientation, the design of smooth fiber helps to maintain the stability of numerical calculation and the compatibility of the manufacturing process. However, the improvement of fiber continuity is often accompanied by a significant decrease in the overall structural stiffness. Aiming at this problem, this paper proposes a topology optimization method for anisotropic materials with smooth fiber orientation. This method improves the smoothness of fiber orientation and reduces stiffness loss by introducing a fiber angle constraint strategy and adaptive filtering technology. The fiber angle constraint strategy integrates the created angle constraint function into the Method of Moving Asymptotes (MMA) to complete the strong constraint of the angle. This strategy quantifies the continuity of the fiber and effectively improves the continuity of the fiber. At the same time, the application of adaptive filtering technology can adjust a reasonable fiber angle distribution on the basis of smoothing fibers, thereby enhancing the stiffness of the overall structure. In addition, this paper shows the complete optimization process and MATLAB code implementation and verifies the effectiveness of the method through a series of numerical examples, that is, on the basis of improving fiber continuity, the stiffness of the whole structure is guaranteed, and then the effective balance between the two is realized. Full article

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26 pages, 28194 KiB

Open AccessArticle

Propagation Characteristics of Initial Compression Wave Induced by 400 km/h High-Speed Trains Passing through Very Long Tunnels

by Kang Wei, Yuangui Mei, Qi Sun and Xiao Hu

Appl. Sci. 2024, 14(13), 5946; https://doi.org/10.3390/app14135946 - 8 Jul 2024

Viewed by 316

Abstract

When high-speed trains enter tunnels, an initial compression wave is generated. As the compression wave propagates at the local speed of sound to the tunnel exit, it radiates into the surrounding environment, forming micro-pressure waves (MPWs). MPWs create sonic booms, resulting in significant [...] Read more.

When high-speed trains enter tunnels, an initial compression wave is generated. As the compression wave propagates at the local speed of sound to the tunnel exit, it radiates into the surrounding environment, forming micro-pressure waves (MPWs). MPWs create sonic booms, resulting in significant environmental issues. The magnitude of the micro-pressure waves is directly proportional to the pressure gradient of the compression wave at the tunnel exit. The nonlinear effects of the initial compression wave during propagation lead to a significant increase in pressure gradient. Therefore, the propagation characteristics of the initial compression wave during the tunnel are the crucial factor affecting the amplitude of MPWs. Based on the one-dimensional compressible unsteady non-isentropic flow model and the improved generalized Riemann variable characteristic method, this paper researched the propagation and evolution characteristics of an initial compression wave generated when 400 km/h high-speed trains enter tunnels with three portal shapes: (no tunnel entrance hood (no hood), an oblique, enlarged tunnel entrance hood (type A), an enlarged equal-section non-uniform opening hole tunnel entrance hood (type B)). The results show that when the initial compression wave propagates inside very long tunnels, the pressure gradient of the compression wave exhibits a trend of initially increasing and then decreasing with the increase in propagation distance. When the pressure gradient of the compression wave reaches its maximum value, the corresponding propagation distance is the steepening critical distance. For no tunnel entrance hoods, type A tunnel entrance hoods, and type B tunnel entrance hoods, the steepening critical distances are 5 km, 6 km, and 16 km, respectively. The steepening critical distance shortens with increasing train speed. Steady friction and unsteady friction effects mainly affect the pressure amplitude and pressure gradient during compression wave propagation, respectively. At lower ambient temperatures, the nonlinear effects in compression wave propagation are significantly enhanced. The mitigation effects of type A tunnel entrance hoods and type B tunnel entrance hoods on pressure gradient reduction are mainly concentrated within 4 km and 12 km, respectively. It is necessary to determine the optimal matching relationship between the tunnel entrance hood and tunnel length based on the characteristics of compression wave propagation to ensure their mitigating performance is maximized. Full article

(This article belongs to the Special Issue New Insights into Railway Vehicle Dynamics)

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21 pages, 6121 KiB

Open AccessArticle

Spatio-Temporal Variations in Soil Erosion and Its Driving Forces in the Loess Plateau from 2000 to 2050 Based on the RUSLE Model

by Jie Min, Xiaohuang Liu, Hongyu Li, Ran Wang and Xinping Luo

Appl. Sci. 2024, 14(13), 5945; https://doi.org/10.3390/app14135945 - 8 Jul 2024

Viewed by 381

Abstract

Assessing the spatio-temporal variability and driving forces of soil erosion on the Loess Plateau is critical for ecological and environmental management. In this paper, the Revised Universal Soil Loss Equation (RUSLE) model, the patch-generating land use simulation, and the Geographical Detector are used [...] Read more.

Assessing the spatio-temporal variability and driving forces of soil erosion on the Loess Plateau is critical for ecological and environmental management. In this paper, the Revised Universal Soil Loss Equation (RUSLE) model, the patch-generating land use simulation, and the Geographical Detector are used to investigate the spatio-temporal variations of the Loess Plateau’s soil erosion from 2000 to 2050. The results showed that: (1) The primary categories of soil erosion from 2000 to 2020 were moderate, mild, and slight, and the average level of soil erosion exhibited a decreasing and then an increasing tendency during the last 20 years. (2) Soil erosion was directly impacted by changes in land use, with cropland and forest being the primary land use and land cover changes in the study region. Cropland and construction land being turned into woodland between 2000 and 2020 resulted in a significant decrease in the severity of soil erosion. Projected soil erosion is expected to increase significantly between 2020 and 2050 due to arable land being converted into construction land. (3) The key variables impacting the spatial distribution of soil erosion were LUCC (Land-Use and Land-Cover Change), NDVI (Normalized Difference Vegetation Index), and slope, and the interplay of these variables may increase their ability to explain soil erosion. Grasslands with an NDVI ranging from 0.9 to 1, rain ranging from 0.805 to 0.854 m, a slope above 35°, and a terrain elevation ranging from 1595 to 2559 m were identified as having a high risk of soil erosion. Soil erosion prevention and management efforts should focus on the ecological restoration of upland areas in the future. Full article

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20 pages, 6636 KiB

Open AccessArticle

Three-Dimensional Guidance Laws for Spacecraft Propelled by a SWIFT Propulsion System

by Alessandro A. Quarta

Appl. Sci. 2024, 14(13), 5944; https://doi.org/10.3390/app14135944 - 8 Jul 2024

Viewed by 322

Abstract

This paper discusses the optimal control law, in a three-dimensional (3D) heliocentric orbit transfer, of a spacecraft whose primary propulsion system is a Solar Wind Ion Focusing Thruster (SWIFT). A SWIFT is an interesting concept of a propellantless thruster, proposed ten years ago [...] Read more.

This paper discusses the optimal control law, in a three-dimensional (3D) heliocentric orbit transfer, of a spacecraft whose primary propulsion system is a Solar Wind Ion Focusing Thruster (SWIFT). A SWIFT is an interesting concept of a propellantless thruster, proposed ten years ago by Gemmer and Mazzoleni, which deflects, collects, and accelerates the charged particles of solar wind to generate thrust in the interplanetary space. To this end, the SWIFT uses a large conical structure made of thin metallic wires, which is positively charged with the aid of an electron gun. In this sense, a SWIFT can be considered as a sort of evolution of the Janhunen’s E-Sail, which also uses a (nominally flat) mesh of electrically charged tethers to deflect the solar wind stream. In the recent literature, the optimal performance of a SWIFT-based vehicle has been studied by assuming a coplanar orbit transfer and a two-dimensional scenario. The mathematical model proposed in this paper extends that result by discussing the optimal guidance laws in the general context of a 3D heliocentric transfer. In this regard, a number of different forms of the spacecraft state vectors are considered. The validity of the obtained optimal control law is tested in a simplified Earth–Venus and Earth–Mars transfer by comparing the simulation results with the literature data in terms of minimum flight time. Full article

(This article belongs to the Special Issue Advances in Deep Space Probe Navigation)

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18 pages, 3821 KiB

Open AccessArticle

A Placement Method of the 5G Edge Nodes Based on the Hotspot Distribution of Mobile Users

by Ruowei Gui, Xingjun Zhang, Xiaolin Gui and Jinsong Han

Appl. Sci. 2024, 14(13), 5943; https://doi.org/10.3390/app14135943 - 8 Jul 2024

Viewed by 330

Abstract

Due to the emergence of various new applications, such as short videos and online games, higher requirements of their computing and storage capacity are demanded of mobile networks. The traditional cloud computing paradigm has the shortcomings of large latency and high bandwidth demand [...] Read more.

Due to the emergence of various new applications, such as short videos and online games, higher requirements of their computing and storage capacity are demanded of mobile networks. The traditional cloud computing paradigm has the shortcomings of large latency and high bandwidth demand of the core network. Therefore, how to mine the hotspot distribution of these applications and reasonably configure 5G edge nodes to reduce latency and core network bandwidth are facing great challenges. To address these issues, we designed a placement method for the 5G edge nodes based on mobile hotspots. In this method, we first cluster all locations from the user trajectories to obtain the cluster areas. Further, we extract the features, such as the number of users and duration time in all cluster areas, and extract the hotspots from all cluster areas based on the features of each cluster. Then, we introduce the base station’s high load utilization rate and the core network’s bandwidth reduction rate as the optimization parameters to construct the mathematical model of multi-objective optimization. Finally, we formalize the model into a 0–1 integer programming problem and design a greedy algorithm to solve this model. We also complete a series of experiments to evaluate our proposed methods using the GeoLife dataset. The experimental results show that the high load utilization rate can be increased up to 7.69%, and the bandwidth reduction rate of the core network can be improved up to 6.34%. Full article

(This article belongs to the Special Issue 5G and Beyond: Technologies and Communications)

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12 pages, 5147 KiB

Open AccessArticle

Comparative Analysis of Tribological Behavior of 45 Steel under Intensive Quenching-High-Temperature Tempering and Queenching-Tempering Process

by Xiyang Su, Xiaoshuo Zhu, Yudong Fu, Shichen Xiao and Yuchao Liu

Appl. Sci. 2024, 14(13), 5942; https://doi.org/10.3390/app14135942 - 8 Jul 2024

Viewed by 317

Abstract

The intensive quenching process compared to traditional methods results in a lower quenching cracking tendency. The comprehensive mechanical properties of an intensive quenching workpiece has good advantages. In order to improve the performance and product quality of a 45 steel workpiece, the hardening–tempering [...] Read more.

The intensive quenching process compared to traditional methods results in a lower quenching cracking tendency. The comprehensive mechanical properties of an intensive quenching workpiece has good advantages. In order to improve the performance and product quality of a 45 steel workpiece, the hardening–tempering treatment used in the traditional quenching process is replaced by an intensive quenching process. This study investigates the tribological properties of 45 steel and their differences and connection under the intensive quenching and high-temperature tempering process in comparison to when under the traditional hardening–tempering process. Both intensive quenching and tempering and hardening–tempering workpieces are composed of carburized particles and ferrite. Compared with hardening–tempering workpieces, intensive quenching and high-temperature tempering workpieces have a finer and more uniform microstructure and higher hardness, impact toughness, and yield strength. Wear tests show that intensive quenchingand tempered specimens have better wear resistance. At the same frequency, the coefficient of friction and relative wear rate of the intensive quenching and tempering specimens were lower than those of the hardening–tempering treatment, and the wear surface was flatter. The wear morphology shows that the main wear mechanisms of the intensive quenching and tempering workpieces and those of hardening–tempering are abrasive and adhesive wear, and that the main wear mechanism changes from adhesive wear to abrasive wear as the frequency increases. Full article

(This article belongs to the Section Additive Manufacturing Technologies)

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16 pages, 4884 KiB

Open AccessArticle

Experimental Study on Prefabricated Steel Fiber-Reinforced Concrete Casing Arch Method for Strengthening Cracked Lining in Confined Spaces

by Yu Zhou, Zhi Lin, Lili Liu and Jianghao Zhou

Appl. Sci. 2024, 14(13), 5941; https://doi.org/10.3390/app14135941 - 8 Jul 2024

Viewed by 341

Abstract

Increasingly, research indicates that steel fibers can significantly enhance the engineering properties of mortar and concrete; however, few studies have examined their impact on the reinforcement of in-service tunnel linings within sleeve arch structures. In this study, a series of 1:2 scale experiments [...] Read more.

Increasingly, research indicates that steel fibers can significantly enhance the engineering properties of mortar and concrete; however, few studies have examined their impact on the reinforcement of in-service tunnel linings within sleeve arch structures. In this study, a series of 1:2 scale experiments were conducted using a specialized loading device to compare the reinforcement performance of steel fiber-reinforced concrete sleeve arches and traditional reinforced concrete sleeve arches on prefabricated cracks with depths of 1/3 and 2/3 of the lining thickness. The experimental results were validated using numerical simulations. The results indicate that under the same load, when reinforcing components with 2/3 prefabricated cracks, the maximum compressive strains for steel fiber-reinforced and reinforced concrete sleeve arches were −852 με and −985 με, respectively, and the maximum deflections were 3.57 mm and 5.48 mm. Composite sleeve arches of both materials provide a certain degree of reinforcement to linings with varying damage. The reinforcement performance of steel fiber-reinforced concrete sleeve arches is superior to that of traditional reinforced concrete sleeve arches, with particularly significant reinforcement for linings with 2/3 prefabricated cracks. Numerical simulations have shown that the stress in reinforced concrete at the concentrated stress regions is 16.15%, 6.01%, 12.68%, 36.62%, and 4.82% higher than that in steel fiber-reinforced concrete, respectively, thereby validating the reliability of the experimental results. Therefore, this study recommends the application of steel fiber materials in sleeve arches to achieve superior maintenance and reinforcement, addressing cracking issues in in-service tunnel linings and thereby improving the safety and durability of these structures. Full article

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15 pages, 1832 KiB

Open AccessArticle

Study on the Vibration Effects of Cyclic Blasting on Bridge Structures under Construction

by Yunhao Che and Enan Chi

Appl. Sci. 2024, 14(13), 5940; https://doi.org/10.3390/app14135940 - 8 Jul 2024

Viewed by 318

Abstract

This study investigates the impact of cyclic tunnel blasting on adjacent bridge structures under construction. Monitoring vibration velocities of the bridge deck, piers, and middle column adjacent to the Zhanma Tian Tunnel, a three-dimensional numerical model was developed using FLAC3D software, utilizing blasting [...] Read more.

This study investigates the impact of cyclic tunnel blasting on adjacent bridge structures under construction. Monitoring vibration velocities of the bridge deck, piers, and middle column adjacent to the Zhanma Tian Tunnel, a three-dimensional numerical model was developed using FLAC3D software, utilizing blasting vibration test data from the Zhanma Tian Tunnel project in Guizhou. Results show that, as the distance between the bridge and tunnel increases, vibration velocity at the bridge deck decreases more rapidly compared to the base of the pier. Peak vibration velocities recorded were 0.235 cm/s for the bridge deck, 0.081 cm/s for the pier base, and a predicted 0.209 cm/s for the middle column. The impact order from blasting vibrations on the bridge structure is: pier base, middle column, bridge deck. Peak vibration velocity induced by blasting ranged between 0.05 and 0.25 cm/s, within safe limits of bridge material strength. Eight daily blasting cycles do not compromise the safety of bridge structures located 43 m away. Full article

(This article belongs to the Special Issue Recent Advances in the Effect of Blast Loads on Structures)

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15 pages, 518 KiB

Open AccessArticle

On the Analysis of Coverage Feedback in a Fuzzing Proprietary System

by Daehee Jang, Jaemin Kim, Jiho Kim, Woohyeop Im, Minwoo Jeong, Byeongcheol Choi and Chongkyung Kil

Appl. Sci. 2024, 14(13), 5939; https://doi.org/10.3390/app14135939 - 8 Jul 2024

Viewed by 413

Abstract

Coverage feedback is one of the key mechanisms for improving the effectiveness of fuzzers by measuring and comparing the executed code regions while processing input data. In general, such guidance should always improve the performance of fuzzers to better find unexplored code regions. [...] Read more.

Coverage feedback is one of the key mechanisms for improving the effectiveness of fuzzers by measuring and comparing the executed code regions while processing input data. In general, such guidance should always improve the performance of fuzzers to better find unexplored code regions. However, proprietary systems with uncommon I/O interfaces (e.g., UAV system, IoT devices, satellite firmware) require extensive engineering/porting efforts to apply coverage feedback support in developing their fuzzing platform. In this paper, we evaluate the detailed efficacy of coverage feedback in fuzzing based on 44 real-world bugs we found using OSS-Fuzz. Our analysis uncovered when and how code coverage information can be helpful, and our experiment demonstrates that although coverage guidance is always helpful to some extent, its effectiveness depends on various external factors. Therefore, such factors should be carefully considered for optimizing the cost and efficiency in designing the fuzzing architecture of proprietary systems. Full article

(This article belongs to the Special Issue Advances in Unmanned Aerial Vehicle (UAV) System)

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12 pages, 5767 KiB

Open AccessCommunication

A Multi-Channel Data Simulator Based on the Time Unification System

by Jingyi Yu, Runjiang Dou, Xiuyu Wang, Jiangtao Xu, Jian Liu, Nanjian Wu and Liyuan Liu

Appl. Sci. 2024, 14(13), 5938; https://doi.org/10.3390/app14135938 - 8 Jul 2024

Viewed by 344

Abstract

In satellite and airborne electro-optical tracking systems, there are numerous processing devices and complex data flows. To ensure the coordinated operation of the system, the multiple devices within the target system must operate under unified time control for data acquisition, computation, and output. [...] Read more.

In satellite and airborne electro-optical tracking systems, there are numerous processing devices and complex data flows. To ensure the coordinated operation of the system, the multiple devices within the target system must operate under unified time control for data acquisition, computation, and output. This study introduces a multi-channel data simulator based on a time unification system. The complete simulation system includes the host computer, simulator, target system, and time reference generator. The simulator has programmable input and output interfaces for multi-channel protocols and has storage and real-time working modes. In the storage mode, the simulated data are pre-transmitted to the simulator’s storage and sent to the target system according to the time reference generator. The simulator simultaneously stores the target system results. In the real-time mode, the host computer generates simulated data based on the target system’s results and outputs the data through the simulator in real time. The main contribution of the simulator is that it achieves system-level closed-loop simulation and completes the functional and performance verification of the target system. Through experimental verification, it is found that the simulator can achieve 4.2 Gbps of simulated data transmission and 1.6 Gbps of data reception and storage, with a closed-loop delay of 39.9 µs. Full article

(This article belongs to the Section Electrical, Electronics and Communications Engineering)

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16 pages, 3838 KiB

Open AccessArticle

Characterization and Theoretical Analysis of the Venus Flytrap Trigger Hair

by Yanhao Qian, Siyuan Chen, Zihao Zhang, Guanyu Bao, Mingchen Ma, Kejun Wang, Chao Liu and Qian Wang

Appl. Sci. 2024, 14(13), 5937; https://doi.org/10.3390/app14135937 - 8 Jul 2024

Viewed by 345

Abstract

The Venus flytrap, which possesses a number of mechano-sensitive trigger hairs, is a typical carnivorous plant that effectively senses and catches insects to survive in nutrient-poor habitats. When insects touch the trigger hairs on a leaf, once they reach the threshold, the Venus [...] Read more.

The Venus flytrap, which possesses a number of mechano-sensitive trigger hairs, is a typical carnivorous plant that effectively senses and catches insects to survive in nutrient-poor habitats. When insects touch the trigger hairs on a leaf, once they reach the threshold, the Venus flytrap induces an action potential and sharply closes to capture the prey. In this paper, the trigger hairs obtain a special cantilever beam structure with a stiff hair lever and a flexible basal podium, and there is a noticeable notched structure at the basal podium, which differs from a common homogeneous hair. Based on the characteristics of the Venus flytrap trigger hairs, we established a three-dimensional model and conducted theoretical and finite element analysis. The results show that the unique hollow heterogeneous cantilever structure of the Venus flytrap trigger hair can achieve high sensitivity and optimal tactile perception. Overall, the morphology, structure and mechanical characteristics of Venus flytrap trigger hairs were characterized in detail, which may provide a deeper understanding of the trigger hairs’ tactile perception mechanism. And the mechanical simulation and optimization analysis of Venus flytrap trigger hairs had an important theoretical basis and parameter support for the further design of state-of-the-art tactile sensors with high sensitivity inspired by Venus flytrap trigger hairs. Full article

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19 pages, 5739 KiB

Open AccessArticle

Exploring Recycled Polyethylene Terephthalate (PET) Based Cushioning Design to Reduce Bruise Damage in Pears

by Asma Mecheter, Faris Tarlochan and Pankaj B. Pathare

Appl. Sci. 2024, 14(13), 5936; https://doi.org/10.3390/app14135936 - 8 Jul 2024

Viewed by 368

Abstract

Post-harvest activities, which include sorting, loading, unloading, and transporting, are potential factors that cause mechanical damage and bruises to fresh produce. This would directly impact fruit shelf-life and, therefore, cause economic losses. This study developed a finite element (FE) model for pear fruit [...] Read more.

Post-harvest activities, which include sorting, loading, unloading, and transporting, are potential factors that cause mechanical damage and bruises to fresh produce. This would directly impact fruit shelf-life and, therefore, cause economic losses. This study developed a finite element (FE) model for pear fruit where a steel impactor drop-based test was utilized. The FE model was validated by evaluating it as the experimental model in order to identify bruises of the pear fruit. Therefore, to minimize bruises on the pear fruit, a recycled polyethylene terephthalate (PET) spring-based design was proposed in order to serve as a cushioning design for pear fruits. Design of experiments and response surface methodology were performed in order to minimize the fruit bruise susceptibility response subject to different spring design parameters. The results revealed that reduced spring pitch and increased coil thickness would significantly minimize bruises of pear fruit. The recycled PET proposed design proved its efficiency in reducing FE pear fruit model bruises by about 50%. This study provides insights on assessing bruise susceptibility using finite element analysis and reusing plastic for fresh produce packaging, thus reducing loops in supply chains and achieving a circular economy. Full article

(This article belongs to the Section Agricultural Science and Technology)

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