Applied Sciences

15 pages, 8062 KiB

Open AccessArticle

Exploring Asymmetric Lens–Total Internal Reflection (AL–TIR) Optics for Uniform Ceiling Illumination in Interior Lighting

by Duong Thi Giang, Pham Hong Duong and Tran Quoc Khanh

Appl. Sci. 2024, 14(21), 10081; https://doi.org/10.3390/app142110081 - 4 Nov 2024

Viewed by 768

Abstract

This study presents a significant advancement in LED interior lighting through the development and application of Asymmetric Lens–Total Internal Reflection (AL–TIR) optics, with a focus on enhancing lighting uniformity and indoor comfort by simulating sky-like lighting distribution. AL–TIR technology employs asymmetric lenses combined [...] Read more.

This study presents a significant advancement in LED interior lighting through the development and application of Asymmetric Lens–Total Internal Reflection (AL–TIR) optics, with a focus on enhancing lighting uniformity and indoor comfort by simulating sky-like lighting distribution. AL–TIR technology employs asymmetric lenses combined with total internal reflection to efficiently redirect and spread light, achieving a controlled and even ceiling illumination suitable for various interior applications. This research explored the establishment of ideal luminous intensity curves, devised practical AL–TIR optical designs through numerical calculations, and conducted extensive simulations to assess performance in typical indoor environments. Our findings demonstrated substantial improvements in lighting uniformity, with the AL and AL–TIR systems achieving direct illuminance uniformities of 0.78 and 0.83, respectively, compared to traditional tube LEDs at 0.25. These results, validated in several office rooms, highlight the efficacy of AL–TIR optics in revolutionizing indoor lighting design by balancing optimal lighting distribution with occupant comfort and well-being. Full article

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16 pages, 5108 KiB

Open AccessArticle

Experimental Evaluation of Gas-Dynamic Conditions of Heat Exchange of Stationary Air Flows in Vertical Conical Diffuser

by Leonid Plotnikov, Mikhail Ershov, Alexander Nikitin, Vladimir Tuponogov and Alexander Ryzhkov

Appl. Sci. 2024, 14(21), 10080; https://doi.org/10.3390/app142110080 - 4 Nov 2024

Viewed by 720

Abstract

Conical diffusers are widely used in technical devices (gasifiers, turbines, combustion chambers) and technological processes (ejectors, mixers, renewable energy). The perfection of flow gas dynamics in a conical diffuser affects the intensity of heat and mass transfer processes, the quality of mixing/separation of [...] Read more.

Conical diffusers are widely used in technical devices (gasifiers, turbines, combustion chambers) and technological processes (ejectors, mixers, renewable energy). The perfection of flow gas dynamics in a conical diffuser affects the intensity of heat and mass transfer processes, the quality of mixing/separation of working media and the flow characteristics of technical devices. These parameters largely determine the efficiency and productivity of the final product. This article presents an analysis of experimental data on the gas-dynamic characteristics of stationary air flows in a vertical, conical, flat diffuser under different initial boundary conditions. An experimental setup was created, measuring instruments were selected, and an automated data collection system was developed. Basic data on the gas dynamics of air flows were obtained using the thermal anemometry method. Experimental data on instantaneous values of air flow velocity in a diffuser for initial velocities from 0.4 m/s to 2.22 m/s are presented. These data were the basis for calculating and obtaining velocity fields and turbulence intensity fields of the air flow in a vertical diffuser. It is shown that the value of the initial flow velocity at the diffuser inlet has a significant effect on the gas-dynamic characteristics. In addition, a spectral analysis of the change in air flow velocity both by height and along the diffuser axis was performed. The obtained data may be useful for refining engineering calculations, verifying mathematical models, searching for technical solutions and deepening knowledge about the features of gas dynamics of air flows in vertical diffusers. Full article

(This article belongs to the Special Issue Advances in Active and Passive Techniques for Fluid Flow Manipulation)

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17 pages, 1265 KiB

Open AccessArticle

Message Action Adapter Framework in Multi-Agent Reinforcement Learning

by Bumjin Park and Jaesik Choi

Appl. Sci. 2024, 14(21), 10079; https://doi.org/10.3390/app142110079 - 4 Nov 2024

Viewed by 838

Abstract

Multi-agent reinforcement learning (MARL) has demonstrated significant potential in enabling cooperative agents. The communication protocol, which is responsible for message exchange between agents, is crucial in cooperation. However, communicative MARL systems still face challenges due to the noisy messages in complex multi-agent decision [...] Read more.

Multi-agent reinforcement learning (MARL) has demonstrated significant potential in enabling cooperative agents. The communication protocol, which is responsible for message exchange between agents, is crucial in cooperation. However, communicative MARL systems still face challenges due to the noisy messages in complex multi-agent decision processes. This issue often stems from the entangled representation of observations and messages in policy networks. To address this, we propose the Message Action Adapter Framework (MAAF), which first trains individual agents without message inputs and then adapts a residual action based on message components. This separation isolates the effect of messages on action inference. We explore how training the MAAF framework with model-agnostic message types and varying optimization strategies influences adaptation performance. The experimental results indicate that MAAF achieves competitive performance across multiple baselines despite utilizing only half of the available communication, and shows an average improvement of 7.6% over the full attention-based communication approach. Additional findings suggest that different message types result in significant performance variations, emphasizing the importance of environment-specific message types. We demonstrate how the proposed architecture separates communication channels, effectively isolating message contributions. Full article

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

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Graphical illustration of two types of actions. The observation action is a non-cooperative behavior in which the prey can easily escape the predators. On the other hand, the messages encourage better cooperative behavior. The messages contribute to residuals of actions; the final actions combine the base actions and the residuals. Full article ">Figure 2
Graphical models for the forward action process in policy networks. Previous MARL methods link hidden representations to an intermediate hidden layer (Hidden2), resulting in entangled representations. In contrast, the proposed action adaptation restricts the contribution of messages to the action logit, offering a more disentangled integration. The interaction between observation and messages can be constructed by passing observation to the message (dashed line). Full article ">Figure 3
Graphical illustration of MAAF. (Left) Two steps for training: a base policy and a message adapter policy (blue and orange regions). In step 1, the agent learns to maximize the environment return without communication. In step 2, the agent generates messages and communicates with cooperative agents. The adapter policy produces a residual action <math display="inline"><semantics> <msup> <mi>A</mi> <mo>′</mo> </msup> </semantics></math> resulting in the final action <math display="inline"><semantics> <mover accent="true"> <mi>A</mi> <mo>˜</mo> </mover> </semantics></math>. In the training of the adapter policy, the parameters of the base policy are fixed. (Right) Overview of MARL control for two steps. Each agent produces action and communicates by generating messages. Full article ">Figure 4
Graphical illustration of message generation. The combination of four types generates message M for cooperative agents. Optionally, a user can feed a new message input type to utilize communication. Full article ">Figure 5
Rendering of three environments. In the spread environment, three agents (purple circles) must spread as far as possible while staying near target locations (small black circles). In the tag environments, three predators (red circles) chase prey (a green circle) in an environment with obstacles. In SMAC environments, two groups of agents fight each other. Full article ">Figure 6
Episode returns for three optimizations (Y-axis) for 2M time steps (X-axis). Adaptations are started at the 1M time step. The results indicate that updating both policies (red) is better than freezing blue). The shaded regions are confidence intervals obtained by three random seeds. Full article ">Figure 7
Episode returns for message types. The solid lines are the cases when updating base and adaptation policies, and the dashed lines are cases when the base policies are not updated. Each color represents different message types in <math display="inline"><semantics> <msub> <mi mathvariant="script">S</mi> <mo form="prefix">Comb</mo> </msub> </semantics></math>. When freezing, the performance drops after the 1M time step, indicating that updating both networks is robust for message types. Full article ">Figure 8
Episodic return while training five MARL agents for the best hyperparameter settings and three random seeds. We observe the competitive performance of MAPPO for all environments. In the tag environment, where communication between agents is crucial to tracking moving agents, the proposed MAAF variants perform better than all the baselines. However, MAAF shows weak results in SMAC environments where the number of actions is too large to be adapted. Therefore, MAAF shows a large gap to MAPPO in SMAC.8M, which has eight agents. Full article ">Figure 9
Box plots of normalized returns for different environments. Each plot is obtained by running three seeds. In a spread environment, we observed no difference between message types, indicating that the contribution of messages is weak. In the tag environment, the performance increases as communication message types become complex. In SMAC environments, simple messages, such as only having observation or action, provide better performance than having complex message types. These results indicate that feature selection on message types is necessary for MARL communication. Full article ">Figure 10
Box plots of returns of tag environments for different numbers of predators (the number in the naming represents the number of predators). Each plot is obtained by running three seeds. In Tag-2, the performance drops as the communication channel includes more message types. In Tag-3, the performance increases as the complexity of the communication channel increases. The action information is especially beneficial, and the best performance is obtained with both action and probability. This correlation between the complexity of message channels and environments no longer holds in Tag-4. Therefore, searching for the optimal combination might be necessary. Full article ">Figure 11
Trajectories for the base and adapted policies (with message cases) in the spread environment. Black and blue stars are the locations of three agents with and without communication, respectively. The darker color represents later time steps. Diamond is the target location where three agents (represented by stars) must be close to obtain rewards while separating each other. Full article ">Figure 12
Counterfactual interpretation of actions following the trajectory of a base policy. Each panel shows the trajectories of an episode in the Tag environment, featuring two predators and one prey. The trajectories are represented by stars, with darker colors indicating later time steps. Green arrows represent the prey’s actions, while red arrows show the actions of the predators. The gray arrows denote counterfactual actions generated through communication between predators. This setup allows us to interpret actions without communication and compare them to cooperative actions facilitated by communication. Full article ">Figure A1
Pseudo-code for computing action logits in two configurations: (1) Base Actor, which computes logits solely from observations, and (2) Adapter Actor, which incorporates both observations and messages. In the Adapter Actor computation, logits from the base and adapter networks are linearly combined to produce the final action logits. Full article ">

18 pages, 3939 KiB

Open AccessReview

Towards Reliable ECG Analysis: Addressing Validation Gaps in the Electrocardiographic R-Peak Detection

by Syed Talha Abid Ali, Sebin Kim and Young-Joon Kim

Appl. Sci. 2024, 14(21), 10078; https://doi.org/10.3390/app142110078 - 4 Nov 2024

Viewed by 842

Abstract

Electrocardiographic (ECG) R-peak detection is essential for every sensor-based cardiovascular health monitoring system. To validate R-peak detectors, comparing the predicted results with reference annotations is crucial. This comparison is typically performed using tools provided by the waveform database (WFDB) or custom methods. However, [...] Read more.

Electrocardiographic (ECG) R-peak detection is essential for every sensor-based cardiovascular health monitoring system. To validate R-peak detectors, comparing the predicted results with reference annotations is crucial. This comparison is typically performed using tools provided by the waveform database (WFDB) or custom methods. However, many studies fail to provide detailed information on the validation process. The literature also highlights inconsistencies in reporting window size, a crucial parameter used to compare predictions with expert annotations to distinguish false peaks from the true R-peak. Additionally, there is also a need for uniformity in reporting the total number of beats for individual or collective records of the widely used MIT-BIH arrhythmia database. Thus, we aim to review validation methods of various R-peak detection methodologies before their implementation in real time. This review discusses the impact of non-beat annotations when using a custom validation method, allowable window tolerance, the effects of window size deviations, and implications of varying numbers of beats and skipping segments on ECG testing, providing a comprehensive guide for researchers. Addressing these validation gaps is critical as they can significantly affect validatory outcomes. Finally, the conclusion section proposes a structured concept as a future approach, a guide to integrate WFDB R-peak validation tools for testing any QRS annotated ECG database. Overall, this review underscores the importance of complete transparency in reporting testing procedures, which prevents misleading assessments of R-peak detection algorithms and enables fair methodological comparison. Full article

(This article belongs to the Special Issue Applied Electronics and Functional Materials)

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17 pages, 2340 KiB

Open AccessArticle

Deciphering the Driving Mechanism and Regulatory Strategies of Antibiotic Resistance Genes Transmission in Lead-Contaminated Soil Microbial Communities by Multiple Remediation Methods

by Yafei Wang, Hang Yu, Lingwei Meng, Yuhui Cao, Zhihao Dong, Yushan Huang, Yimin Zhu, Qiao Ma, Xiaonan Liu and Wei Li

Appl. Sci. 2024, 14(21), 10077; https://doi.org/10.3390/app142110077 - 4 Nov 2024

Viewed by 825

Abstract

Pb-contaminated soil poses inherent risks for the spread of antibiotic resistance genes (ARGs). However, few reports have investigated the distribution of lead resistance genes (LRGs), particularly their role in ARGs dynamics during Pb-contaminated soil remediation. This study explored the mechanisms driving ARGs variation [...] Read more.

Pb-contaminated soil poses inherent risks for the spread of antibiotic resistance genes (ARGs). However, few reports have investigated the distribution of lead resistance genes (LRGs), particularly their role in ARGs dynamics during Pb-contaminated soil remediation. This study explored the mechanisms driving ARGs variation under different remediation strategies. The results indicated that an increase in the total abundance of ARGs after applying montmorillonite (Imvite), the composite remediation agents of MgO and Ca(H₂PO₄)₂ (MgO-Ca(H₂PO₄)₂), and the composite remediation agents of montmorillonite, MgO, and Ca(H₂PO₄)₂ (Imvite-MgO-Ca(H₂PO₄)₂). Bioelectrochemical systems (BES) effectively reduced ARGs abundance, and when combined with Imvite-MgO-Ca(H₂PO₄)₂, lowered the risk of ARGs proliferation linked to antibiotic deactivation. Changes in Pb concentration and pH reshaped microbial communities, impacting both LRGs and ARGs. To reduce the risk of ARGs proliferation and transmission during, various control strategies, such as modifying Pb stress, adjusting pH, and manipulating microbial community structure, have been proposed. The study provided theoretical foundation and practical strategies for controlling ARGs dissemination during the remediation of heavy metal-contaminated soil. Full article

(This article belongs to the Special Issue Pollution Control and Environmental Remediation)

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Flow chart of different soil remediation methods (The yellow box indicated the groups without BES, while the blue box represented the treatment groups with the composite remediation agent combined with BES). Full article ">Figure 2
Configuration diagram of the BES reactor. Full article ">Figure 3
Relative abundance of various ARG types (a), subtypes (The data was log10(relative abundance)) (b), antibiotic resistance mechanisms (c), and LRGs (d) in soils after different remediation methods. Full article ">Figure 4
Microbial community distribution at the phylum level (a) and genus (b) level after different remediation methods. Full article ">Figure 5
PCoA analysis (a); network analysis of ARGs, LRGs and bacterial at the phylum level (b) and genus level (c) for different remediation methods. Full article ">Figure 6
Redundancy analysis between each factor and ARGs after different remediation methods. Full article ">Figure 7
Regulatory strategies involved in the transmission of ARGs during the remediation of soil Pb contamination. Full article ">

19 pages, 4303 KiB

Open AccessArticle

An Integrated Taylor Expansion and Least Squares Approach to Enhanced Acoustic Wave Staggered Grid Finite Difference Modeling

by Min Zhang, Liming Zhou, Daiguang Fu, Zhixue Chen and Haibo Wu

Appl. Sci. 2024, 14(21), 10076; https://doi.org/10.3390/app142110076 - 4 Nov 2024

Viewed by 697

Abstract

The staggered grid finite difference method has emerged as one of the most commonly used approaches in finite difference methodologies due to its high computational accuracy and stability. Inevitably, discretizing over time and space domains in finite difference methods leads to numerical artifacts. [...] Read more.

The staggered grid finite difference method has emerged as one of the most commonly used approaches in finite difference methodologies due to its high computational accuracy and stability. Inevitably, discretizing over time and space domains in finite difference methods leads to numerical artifacts. This paper introduces a novel approach that combines the widely used Taylor series expansion with the least squares method to effectively suppress numerical dispersion. We have derived the coefficients for the staggered grid finite difference method by integrating Taylor series expansions with the least squares method. To validate the effectiveness of our approach, we conducted analyses on accuracy, dispersion, and stability, alongside simple and complex numerical examples. The results indicate that our method not only inherits the capabilities of the original Taylor series and least squares methods in suppressing numerical dispersion across small and medium wavenumber ranges but also surpasses the original methods. Moreover, it demonstrates robust dispersion suppression capabilities at high wavenumber ranges. Full article

(This article belongs to the Special Issue The Geophysical Method Applied in Engineering and Environment-Related Fields)

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13 pages, 5352 KiB

Open AccessArticle

Numerical Investigation with Failure Characteristic Analysis and Support Effect Evaluation of Deep-Turning Roadways

by Man Wang, Feng Ding, Zehua Niu, Yanan Gao, Huice Jiao and Zhaofan Chen

Appl. Sci. 2024, 14(21), 10075; https://doi.org/10.3390/app142110075 - 4 Nov 2024

Viewed by 657

Abstract

In recent years, tunnel-boring machines (TBMs) have been widely applied in deep coal mining. Turning is an inevitable challenge in TBM tunneling, and a TBM turning roadway exhibits greater instability than a straight roadway, as engineering experience has indicated. This study aimed to [...] Read more.

In recent years, tunnel-boring machines (TBMs) have been widely applied in deep coal mining. Turning is an inevitable challenge in TBM tunneling, and a TBM turning roadway exhibits greater instability than a straight roadway, as engineering experience has indicated. This study aimed to explore the failure mechanism and evaluate the support performance of a deep-turning roadway. Several numerical models were established to investigate the deformation of the roadway, the stress distribution, and the failure zone of the surrounding rocks under different tunneling conditions. The results show that the tunneling depth influences the failure pattern of the turning roadway: deep tunneling with high in situ stress can cause asymmetric failure of the turning roadway, while shallow tunneling with low in situ stress does not. Moreover, the change in turning radius, namely the change in roadway geometry, does not influence the stability of the turning roadway. In addition, the support actions for both the straight and turning roadways do not differ significantly, and the amount of controlled deformation of the surrounding rocks is proportional to their natural deformation. Full article

(This article belongs to the Special Issue Sustainability in the Mechanism and Prevention of Coal-Rock Dynamic Disaster and Rock Engineering)

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29 pages, 12238 KiB

Open AccessArticle

Enhancing Assessment Practices with Moodle: A Comprehensive Study on Teachers’ Use of Different Question Types and the Impact of FastTest PlugIn

by Milagros Huerta-Gomez-Merodio and Maria-Victoria Requena-Garcia-Cruz

Appl. Sci. 2024, 14(21), 10074; https://doi.org/10.3390/app142110074 - 4 Nov 2024

Viewed by 808

Abstract

This study investigates the evolution of online assessment practices through Moodle, a leading Learning Management System (LMS). It explores Moodle’s array of question types alongside the transformative impact of FastTest PlugIn (FTP) on educators’ assessment methods during and after the COVID-19 pandemic. This [...] Read more.

This study investigates the evolution of online assessment practices through Moodle, a leading Learning Management System (LMS). It explores Moodle’s array of question types alongside the transformative impact of FastTest PlugIn (FTP) on educators’ assessment methods during and after the COVID-19 pandemic. This research examines the efficacy of various question types and import formats for large-scale question elaboration. Surveys have been conducted before and after developing courses to train educators on FTP. By analysing trends before and after adopting FTP, the study aims to gain insight into how educators from different universities and disciplines have adapted their assessment strategies among technological advancements. The introduction of FTP has significantly simplified question creation and integration within Moodle. The study also highlights differences in assessment practices between STEM and non-STEM disciplines. Surveys indicate that, following the FTP training course, the use of all question types has increased: Matching (35%), Missing Word (39%), and Cloze (22%). This work provides a comprehensive overview of current LMS trends and Moodle’s evolving role in educational technology. It emphasises the impact of technological advancements, such as FTP, on assessment practices and aims to offer actionable insights for enhancing online assessments. Full article

(This article belongs to the Special Issue The Application of Digital Technology in Education)

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22 pages, 1851 KiB

Open AccessReview

Metabolic Periparturient Diseases in Small Ruminants: An Update

by João Simões and Gisele Margatho

Appl. Sci. 2024, 14(21), 10073; https://doi.org/10.3390/app142110073 - 4 Nov 2024

Viewed by 921

Abstract

Metabolic diseases are significant diseases that affect the welfare, health, and production of small ruminant flocks raised for dairy and meat purposes. In breeding females, they mainly occur from six to eight weeks before and after parturition, respectively. Pregnancy toxemia and lactational ketosis [...] Read more.

Metabolic diseases are significant diseases that affect the welfare, health, and production of small ruminant flocks raised for dairy and meat purposes. In breeding females, they mainly occur from six to eight weeks before and after parturition, respectively. Pregnancy toxemia and lactational ketosis are manifestations of hyperketonemia, primarily due to energetic deficit. Hypocalcemia and hypomagnesemia are related to the metabolic unavailability of calcium and magnesium, respectively. This review aimed to identify and discuss the current and most relevant aspects related to individual and herd health management of these interrelated metabolic diseases with impact on the sheep and goats’ farm sustainability. These diseases are primarily due to nutritional deficits, but homeostatic and homeorhetic disruptions are responsible for clinical signs and forms. Currently, their clinical diagnosis and monitoring are mainly assessed by biochemistry of body fluids and feed bromatological evaluation. Epidemiological studies and measuring risk factors also contribute to their prevention. Nevertheless, research on specific biomarkers and composite indices related to these diseases, in the context of herd health management and precision medicine, are new pathways driven to suitable and efficient animal production. Full article

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

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30 pages, 4521 KiB

Open AccessArticle

NHPP Software Reliability Model with Rayleigh Fault Detection Rate and Optimal Release Time for Operating Environment Uncertainty

by Kwang Yoon Song and In Hong Chang

Appl. Sci. 2024, 14(21), 10072; https://doi.org/10.3390/app142110072 - 4 Nov 2024

Viewed by 763

Abstract

Software is used in diverse settings and depends on development and testing environments. Software development should improve the reliability, quality, cost, and stability of software, making the software testing period crucial. We proposed a software reliability model (SRM) that considers the uncertainty of [...] Read more.

Software is used in diverse settings and depends on development and testing environments. Software development should improve the reliability, quality, cost, and stability of software, making the software testing period crucial. We proposed a software reliability model (SRM) that considers the uncertainty of software environments and the fault detection rate function as a Rayleigh distribution, with an explicit mean value function solution in the model. The goodness-of-fit of the proposed model relative to several existing nonhomogeneous Poisson process (NHPP) SRMs is presented based on three software application failure datasets. Further, a cost model is also presented that addresses the error-removal risk level and required time. The optimal testing release policy for minimizing the expected total cost (ETC) is also determined for NHPP SRMs. The impact of the software environment is studied by varying it, and the optimal release times and minimum ETCs are compared. The goodness-of-fit comparison confirmed that the proposed model has more accurate prediction values than other models. Further, whereas the existing models applied to the cost model do not change after a certain operation period, the proposed model yields changes in release time even for long operating periods. Full article

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17 pages, 4569 KiB

Open AccessArticle

A Novel Breast-Volume Self-Measurement Method with Improved Convenient and Accuracy

by Yulin Zhao, Chihua Wu, Dingbang Luh and Xinyu Zhang

Appl. Sci. 2024, 14(21), 10071; https://doi.org/10.3390/app142110071 - 4 Nov 2024

Viewed by 739

Abstract

Breast volume is crucial for ensuring proper bra fit and comfort, significantly influencing women’s physiological and psychological well-being. This study aims to develop a novel method for breast-volume self-measurement, allowing women to accurately assess their breast volume without specialized equipment. We employed a [...] Read more.

Breast volume is crucial for ensuring proper bra fit and comfort, significantly influencing women’s physiological and psychological well-being. This study aims to develop a novel method for breast-volume self-measurement, allowing women to accurately assess their breast volume without specialized equipment. We employed a geometric approximation of the breast as a combination of a partial elliptical cone and an irregular partial ellipsoid, leading to the formulation of a new volume equation. The method was validated against established standards, including the specimen drainage method and 3D scanning techniques. The findings revealed that our self-measurement approach achieved a relative error of only 3.8%, outperforming the 4.8% of 3D scanning and the 86.3% associated with traditional breast-volume equations. This innovative self-measurement technique enhances accuracy and serves as a practical solution for health and nutritional assessments, alongside body image evaluations. Its user-friendly nature positions it as a valuable tool for women’s health, particularly in personal fitness and ergonomic design. Full article

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19 pages, 720 KiB

Open AccessReview

Bioactive Compounds, Composition and Potential Applications of Avocado Agro-Industrial Residues: A Review

by Alejandra Féliz-Jiménez and Ramon Sanchez-Rosario

Appl. Sci. 2024, 14(21), 10070; https://doi.org/10.3390/app142110070 - 4 Nov 2024

Viewed by 1551

Abstract

In recent years, the global production and industrialization of avocados has led to the generation of large numbers of peel, seeds, and leaf by-products with significant environmental implications. Current efforts, including the Sustainable Development Goals, aim towards the development of sustainable operations through [...] Read more.

In recent years, the global production and industrialization of avocados has led to the generation of large numbers of peel, seeds, and leaf by-products with significant environmental implications. Current efforts, including the Sustainable Development Goals, aim towards the development of sustainable operations through the valorization of waste. Previous research has focused on studying the rich chemical composition of these avocado by-products. Current studies are working on the isolation of polyphenols, flavonoids, phenolic acids and other bioactive compounds found in avocado peel, seeds and leaves for applications in nutraceutical products in the food, pharmaceuticals and cosmetics industries. The inclusion of these extracts in industrial matrices often requires stabilization technologies such as encapsulation emulsions to ensure the delivery and bioactivity of these target compounds. This review will discuss the global production volumes of avocado and its by-products as well as the potential inclusion in various industries based on their chemical compositions. Additionally, this work addresses the various applications that have been previously proposed for the wastes and their extracts. This review also covers the stabilization techniques previously employed in avocado extract treatment, their applications, and the current challenges and opportunities associated with avocado by-products. Full article

(This article belongs to the Special Issue Advanced Food Processing Technologies and Food Quality)

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19 pages, 291 KiB

Open AccessArticle

A Large Language Model and Qualitative Comparative Analysis-Based Study of Trust in E-Commerce

by Laleh Davoodi and József Mezei

Appl. Sci. 2024, 14(21), 10069; https://doi.org/10.3390/app142110069 - 4 Nov 2024

Viewed by 1052

Abstract

The primary goal of this study is to predict and analyze customer trust in e-commerce by leveraging neural computation within large language models (LLMs) alongside configurational approaches. We employ LLMs to predict trust levels based on customer reviews, applying artificial intelligence to analyze [...] Read more.

The primary goal of this study is to predict and analyze customer trust in e-commerce by leveraging neural computation within large language models (LLMs) alongside configurational approaches. We employ LLMs to predict trust levels based on customer reviews, applying artificial intelligence to analyze key aspects of the e-commerce experience, such as customer service, refund processes, item quality, and shipping. To extend beyond predictive performance, we integrate Qualitative Comparative Analysis (QCA) to identify the causal relationships between trust and various stages of the customer journey, including selection, delivery, and post-purchase support (recovery). This dual approach not only showcases the power of neural computation in predicting trust outcomes but also provides a deeper understanding of how specific configurations of customer experience elements contribute to either positive or negative trust. By combining machine learning techniques and QCA, this study contributes to the application of LLMs and configurational approaches, offering novel insights into the drivers of trust in e-commerce. Full article

(This article belongs to the Special Issue Application of Neural Computation in Artificial Intelligence)

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20 pages, 2918 KiB

Open AccessArticle

A Text Generation Method Based on a Multimodal Knowledge Graph for Fault Diagnosis of Consumer Electronics

by Yuezhong Wu, Yuxuan Sun, Lingjiao Chen, Xuanang Zhang and Qiang Liu

Appl. Sci. 2024, 14(21), 10068; https://doi.org/10.3390/app142110068 - 4 Nov 2024

Viewed by 856

Abstract

As consumer electronics evolve towards greater intelligence, their automation and complexity also increase, making it difficult for users to diagnose faults when they occur. To address the problem where users, relying solely on their own knowledge, struggle to diagnose faults in consumer electronics [...] Read more.

As consumer electronics evolve towards greater intelligence, their automation and complexity also increase, making it difficult for users to diagnose faults when they occur. To address the problem where users, relying solely on their own knowledge, struggle to diagnose faults in consumer electronics promptly and accurately, we propose a multimodal knowledge graph-based text generation method. Our method begins by using deep learning models like the Residual Network (ResNet) and Bidirectional Encoder Representations from Transformers (BERT) to extract features from user-provided fault information, which can include images, text, audio, and even olfactory data. These multimodal features are then combined to form a comprehensive representation. The fused features are fed into a graph convolutional network (GCN) for fault inference, identifying potential fault nodes in the electronics. These fault nodes are subsequently fed into a pre-constructed knowledge graph to determine the final diagnosis. Finally, this information is processed through the Bias-term Fine-tuning (BitFit) enhanced Chinese Pre-trained Transformer (CPT) model, which generates the final fault diagnosis text for the user. The experimental results show that our proposed method achieves a 4.4% improvement over baseline methods, reaching a fault diagnosis accuracy of 98.4%. Our approach effectively leverages multimodal fault information, addressing the challenges users face in diagnosing faults through the integration of graph convolutional network and knowledge graph technologies. Full article

(This article belongs to the Special Issue State-of-the-Art of Knowledge Graphs and Their Applications)

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10 pages, 4523 KiB

Open AccessArticle

Influence of Printing Angulation on the Flexural Strength of 3D Printed Resins: An In Vitro Study

by Alessio Casucci, Giulia Verniani, Wissam Sami Haichal, Daniele Manfredini, Marco Ferrari and Edoardo Ferrari Cagidiaco

Appl. Sci. 2024, 14(21), 10067; https://doi.org/10.3390/app142110067 - 4 Nov 2024

Viewed by 871

Abstract

This study compared the flexural strength of various 3D printed resins fabricated at different building angles (0°, 45°, and 90°). Four groups of resins were tested: Varseo Smile Teeth (Bego GmbH & Co., Bremen, Germany), V-print C&B Temp (Voco GmbH, Cuxhaven, Germany), Bego [...] Read more.

This study compared the flexural strength of various 3D printed resins fabricated at different building angles (0°, 45°, and 90°). Four groups of resins were tested: Varseo Smile Teeth (Bego GmbH & Co., Bremen, Germany), V-print C&B Temp (Voco GmbH, Cuxhaven, Germany), Bego Triniq (Bego GmbH & Co. KG, Bremen, Germany), and Sprintray Crown (SprintRay, Los Angeles, CA, USA). A digital light processing 3D printer (Asiga MAX UV, NSW, Sydney, Australia) was used to fabricate the samples at the specified build angles (0°, 45°, and 90°) in accordance with the ISO 4049:2019 standard. Flexural strength was measured using a universal testing machine (Instron 5567; Instron Ltd., Norwood, MA, USA), and fracture analysis was performed using a scanning electron microscope (Jeol JSM-6060LV, Tokyo, Japan). Statistical analysis was carried out using the Statistical Package for the Social Sciences (SPSS, version 26; IBM Corp., Chicago, IL, USA). Means and standard deviations were calculated for each group, and statistical differences were assessed using one-way ANOVA followed by the Bonferroni post hoc test (p < 0.05). All tested resins exhibited high flexural strength values. The maximum flexural strength was observed in the 0° printed samples (137.18 ± 18.92 MPa), while the lowest values were recorded for the 90° printed samples (116.75 ± 24.74 MPa). For V-print C&B Temp, the flexural strength at 90° (116.97 ± 34.87 MPa) was significantly lower compared to the 0° (156.56 ± 25.58 MPa) and 45° (130.46 ± 12.33 MPa) orientations. In contrast, Bego Triniq samples printed at 45° (148.91 ± 21.23 MPa) demonstrated significantly higher flexural strength than those printed at 0° (113.37 ± 31.93 MPa) or 90° (100.96 ± 16.66 MPa). Overall, the results indicate that the printing angle has a significant impact on the flexural strength of the materials, with some resins showing lower strength values at the 90° build angle. Full article

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19 pages, 7111 KiB

Open AccessArticle

Numerical and Experimental Analysis of Roller Hemming on Door Panel’s Curved and Straight-Edge of Flat Plane

by Chaohai Liu and Weimin Lin

Appl. Sci. 2024, 14(21), 10066; https://doi.org/10.3390/app142110066 - 4 Nov 2024

Viewed by 713

Abstract

Owing to its enhanced production efficiency, roller hemming has become the mainstream process for forming and joining metal sheets in the automotive industry. This study investigates the roller hemming process of a specific car door panel through a combination of experimental analysis and [...] Read more.

Owing to its enhanced production efficiency, roller hemming has become the mainstream process for forming and joining metal sheets in the automotive industry. This study investigates the roller hemming process of a specific car door panel through a combination of experimental analysis and finite element analysis (FEA) on both straight-edge and curved-edge flat surfaces. Consequently, the mechanical properties of the door panel, including tensile strength, yield strength, modulus of elasticity, and Poisson’s ratio, were estimated through tensile testing and then underwent finite element modeling. The simulation results demonstrated the varying distribution of stress during the rolling hemming process, with the highest stress concentration observed in the bending area. Additionally, creepage and growing results were acquired from both simulation and experimental data to validate the precision of the numerical model. A comparison was made between the experimental and simulation results of the external forces exerted by the roller on the panel. In both straight- and curved-edge sections, the external force during final hemming exceeded that during pre-hemming, as revealed by experimental measurements of both normal and tangential external forces, surpassing their corresponding simulated values. Full article

(This article belongs to the Section Mechanical Engineering)

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15 pages, 778 KiB

Open AccessArticle

Evaluation of Lower Extremities Power, Movement, Position and Effectiveness in Volleyball

by Gabriel Bobula, Joanna Piech, Artur Płonka, Paweł Król, Wojciech Czarny, Rui Pinto, Damian Pawlik, Łukasz Rydzik and Wojciech Bajorek

Appl. Sci. 2024, 14(21), 10065; https://doi.org/10.3390/app142110065 - 4 Nov 2024

Viewed by 742

Abstract

Background: This paper presents research on the comparison and evaluation of lower limb power, movement, position on the court, and effectiveness in the players of men’s volleyball. The study involved professional players in the first division of a men’s volleyball team. The main [...] Read more.

Background: This paper presents research on the comparison and evaluation of lower limb power, movement, position on the court, and effectiveness in the players of men’s volleyball. The study involved professional players in the first division of a men’s volleyball team. The main aim of this paper was to show the correlation between lower limb power, movement, position on the pitch, and volleyball efficiency. Methods: The authors presented basic somatic characteristics of anthropology metrics, advanced research results obtained with the Optojump measuring system, players’ results statistics obtained with the Data Volley software (v.4.2024.01), and by applying scientific statistical methods and graphics interpretation. Results: The analyses with the Kruskal-Wallis test showed statistically significant differences in all the variables studied. Flight time (TF, H = 122.967; p < 0.001.) was the shortest for the players in the libero position, then the setter, attacker, middle and longest flight time was shown by the receiving players. The height of the jumps (JH, H = 123.018; p < 0.001) was the highest for receiving and mid players, and then attackers and setters, and the lowest jumps were recorded by libero players. The highest power of lower limbs (P, H = 20.392; p < 0.001) was characteristic for receivers, setters, mid-players and, curiously, libero achieved a better result than attackers. Conclusions: The analysis shows that the power of the lower extremities in volleyball players is associated with the function they perform on the court. Full article

(This article belongs to the Special Issue Advances in Sports Training and Biomechanics)

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35 pages, 4036 KiB

Open AccessArticle

Optimization Processes in Automotive Logistic Flow

by Cicerone Laurentiu Popa, Floarea-Loredana Seileanu, Costel Emil Cotet, Florina Chiscop and Constantin-Adrian Popescu

Appl. Sci. 2024, 14(21), 10064; https://doi.org/10.3390/app142110064 - 4 Nov 2024

Viewed by 681

Abstract

This paper presents a logistic flow of assembling automotive rear axles. The product is presented in detail starting from the detailed research and analysis of relevant documentation about its functionality, including the manufacturing logistic flow diagram and the required equipment for the product [...] Read more.

This paper presents a logistic flow of assembling automotive rear axles. The product is presented in detail starting from the detailed research and analysis of relevant documentation about its functionality, including the manufacturing logistic flow diagram and the required equipment for the product manufacturing and assembly. This study is focused on optimizing the logistic flow for the manufacturing and assembly of automotive rear axles using WITNESS Horizon for system modeling and simulation in order to conduct system diagnostics, identify problems, and find solutions that will facilitate the optimization process. The study included a comprehensive assessment of the logistic flow, highlighting the performance of the equipment involved and identifying potential bottlenecks. Using the results obtained after the simulations, the Simplex linear mathematical method was applied to maximize production efficiency and profitability, considering the suppliers’ capacity constraints and the components’ delivery requirements. The results demonstrated a significantly optimized rear-axle production process, with increased profitability and improved productivity by eliminating identified bottlenecks. This research contributes to a deeper understanding of the complexities within the automotive industry and provides a solid foundation for continuously improving manufacturing and assembly processes. Full article

(This article belongs to the Special Issue Design, Analysis, Intelligent Control and Optimization of Industrial and Manufacturing Processes)

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25 pages, 6663 KiB

Open AccessArticle

Optimization of Dynamic Characteristics of Rubber-Based SMA Composite Dampers Using Multi-Body Dynamics and Response Surface Methodology

by Yizhe Huang, Qiyuan Fan, Huizhen Zhang, Lefei Shao and Yuanyuan Shi

Appl. Sci. 2024, 14(21), 10063; https://doi.org/10.3390/app142110063 - 4 Nov 2024

Viewed by 1195

Abstract

The suspension system of a commercial vehicle cab plays a crucial role in enhancing ride comfort by mitigating vibrations. However, conventional rubber suspension systems have relatively fixed stiffness and damping properties, rendering them inflexible to load variations and resulting in suboptimal ride comfort [...] Read more.

The suspension system of a commercial vehicle cab plays a crucial role in enhancing ride comfort by mitigating vibrations. However, conventional rubber suspension systems have relatively fixed stiffness and damping properties, rendering them inflexible to load variations and resulting in suboptimal ride comfort under extreme road conditions. Shape memory alloys (SMAs) represent an innovative class of intelligent materials characterized by superelasticity, shape memory effects, and high damping properties. Recent advancements in materials science and engineering technology have focused on rubber-based SMA composite dampers due to their adjustable stiffness and damping through temperature or strain rate. This paper investigates how various structural parameters affect the stiffness and damping characteristics of sleeve-type rubber-based SMA composite vibration dampers. We developed a six-degree-of-freedom vibration differential equation and an Adams multi-body dynamics model for the rubber-based SMA suspension system in commercial vehicle cabins. We validated the model’s reliability through theoretical analysis and simulation comparisons. To achieve a 45% increase in stiffness and a 64.5% increase in damping, we optimized the suspension system’s z-axis stiffness and damping parameters under different operating conditions. This optimization aimed to minimize the z-axis vibration acceleration at the driver’s seat. We employed response surface methodology to design the composite shock absorber structure and then conducted a comparative analysis of the vibration reduction performance of the optimized front and rear suspension systems. This study provides significant theoretical foundations and practical guidelines for enhancing the performance of commercial vehicle cab suspension systems. Full article

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12 pages, 4778 KiB

Open AccessArticle

Motor Imagery Classification Improvement of Two-Class Data with Covariance Decentering Eigenface Analysis for Brain–Computer Interface Systems

by Hojong Choi, Junghun Park and Yeon-Mo Yang

Appl. Sci. 2024, 14(21), 10062; https://doi.org/10.3390/app142110062 - 4 Nov 2024

Viewed by 686

Abstract

This study is intended to improve the motor imagery classification performance of two-class data points using newly developed covariance decentering eigenface analysis (CDC-EFA). When extracting the classification for the given data points, it is necessary to precisely distinguish the classes because the left [...] Read more.

This study is intended to improve the motor imagery classification performance of two-class data points using newly developed covariance decentering eigenface analysis (CDC-EFA). When extracting the classification for the given data points, it is necessary to precisely distinguish the classes because the left and right features are difficult to differentiate. However, when centering is performed, the unique average data of each feature are lost, making them difficult to distinguish. CDC-EFA reverses the centering method to enhance data characteristics, making it possible to assign weights to data with a high correlation with other data. In experiments with the BCI dataset, the proposed CDC-EFA method was used after preprocessing by filtering and selecting the electroencephalogram data. The decentering process was then performed on the covariance matrix calculated when acquiring the unique face. Subsequently, we verified the classification improvement performance via simulations using several BCI competition datasets. Several signal processing methods were applied to compare the accuracy results of the motor imagery classification. The proposed CDC-EFA method yielded an average accuracy result of 98.89%. Thus, it showed improved accuracy compared with the other methods and stable performance with a low standard deviation. Full article

(This article belongs to the Special Issue Brain-Computer Interfaces: Novel Technologies and Applications)

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Figure 1
Algorithm flowchart of the CDC-EFA method. Full article ">Figure 2
The electrode positions used in the simulation. Full article ">Figure 3
The electrode positions for BCI Competition IV dataset IIa. Full article ">Figure 4
Covariance matrix result changes by CDC (a) without and (b) with whitening methods. (c) The covariance matrix changes using whitening and decentering methods are applied. The x- and y-axes represent the number of trials, while the z-axis (height) corresponds to the values of covariance matrices. Brighter colors indicate higher values, while darker colors represent lower values, i.e., the brighter the color, the higher the value; the darker the color, the lower the value. Full article ">Figure 4 Cont.
Covariance matrix result changes by CDC (a) without and (b) with whitening methods. (c) The covariance matrix changes using whitening and decentering methods are applied. The x- and y-axes represent the number of trials, while the z-axis (height) corresponds to the values of covariance matrices. Brighter colors indicate higher values, while darker colors represent lower values, i.e., the brighter the color, the higher the value; the darker the color, the lower the value. Full article ">Figure 5
Average and maximum accuracy for each method. Full article ">

22 pages, 17675 KiB

Open AccessArticle

Proteome Profiling of Cucurbita pepo Phyllosphere After Infection by Podosphaera xanthii and Application of Reynoutria sachalinensis Extract

by Ioannis Theologidis, Manousos Makridakis, Aikaterini Termentzi, Eirini Baira, Jerome Zoidakis and Dimosthenis Kizis

Appl. Sci. 2024, 14(21), 10061; https://doi.org/10.3390/app142110061 - 4 Nov 2024

Viewed by 903

Abstract

Podosphaera xanthii is the main causal agent of powdery mildew (PM) disease for Cucurbita pepo. Disease control is attained principally by applications of chemical fungicides, along with parallel use of tolerant crop varieties and alternate application of elicitors to control development of disease [...] Read more.

Podosphaera xanthii is the main causal agent of powdery mildew (PM) disease for Cucurbita pepo. Disease control is attained principally by applications of chemical fungicides, along with parallel use of tolerant crop varieties and alternate application of elicitors to control development of disease resistance. To get insight into C. pepo molecular responses to P. xanthii infection and elicitor treatment we studied the proteomic profile differences at the phyllosphere of a zucchini cultivar susceptible to PM, at the onset of P. xanthii (PX) infection and after application of Reynoutria sachalinensis (RS) plant extract, respectively, using a nano-LC-HRMS/MS, Q-Exactive-Orbitrap approach. Analysis of peptide sequences regarding four treatment groups (Control; PX; RS; and RSPX (PX-infected priorly treated with RS)) resulted in 2070 CuGenDB annotations. Three comparisons (treatments vs. Control) encompassed most of the Differentially Expressed Proteins (DEPs). In these three comparisons, KEGG and Gene Ontology functional analyses highlighted unique differentially enriched pathways—some of which included highly expressed proteins—in PX-related (proteasome, pentose phosphate pathway, and carbon fixation), RS-related (biosynthesis of secondary metabolites, flavonoids, and starch and sucrose metabolism), and RSPX-related (pyruvate metabolism and polycomb repressive complex) comparisons, respectively, suggesting distinct mechanisms of early plant responses modulated by PX and RS. Furthermore, in four out of six comparisons the thiamine metabolism pathway was found to be enriched, suggesting a pivotal role in PX-induced responses. Full article

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Figure 1
Heatmap of the top 100 Differentially Expressed Proteins (DEPs) in all C. pepo phyllosphere samples. The horizontal coordinate (dendrogram) on the top represents the clustering of each sample replicate for each treatment. Treatment names are as described in <a href="#applsci-14-10061-t001" class="html-table">Table 1</a>. The vertical coordinate (dendrogram) on the left represents the clustering of DEPs along with protein CuGenDB IDs. The heatmap specifies the relative up- or down-regulation of DEPs according to the log2 Centered Intensity index at the bottom of the heatmap. For each individual heatmap box, the dark red and dark blue colors represent high and low expression, respectively. Full article ">Figure 2
Identification of differentially expressed proteins (DEPs). Volcano plots show the DEPs in each of the six (A–F) comparisons for the four treatments. Treatment names are as described in <a href="#applsci-14-10061-t001" class="html-table">Table 1</a>. The horizontal axis represents the fold change in protein expression between the two sample groups (Log2 fold change), and the vertical axis represents the p-value-based significance of the DEPs between the two sample groups (−Log10 P). Threshold lines for DEPs screening criteria are indicated by dashed lines (placed as a visual aid), with the horizontal line representing the statistical significance threshold (p-value < 0.05) set for the current analysis and the vertical ones placed at fold-change equals two. Non-significant (NS) DEPs (p-value > 0.05) are shown in gray (<2-fold change in expression) and blue (>2-fold change in expression). Significant (p-value < 0.05) up-regulated and down-regulated DEPs are shown as red (<2-fold change) and green (>2-fold change) dots, respectively. Proteins with a 4-fold and above difference in expression are depicted with their corresponding IDs. Full article ">Figure 3
Venn diagrams showing the overlap and differences of DEPs with p-values < 0.05 shared between the three comparisons of treated (PX, RS, RSPX) samples versus the Control. Treatment names are as described in <a href="#applsci-14-10061-t001" class="html-table">Table 1</a>. Overlaps for expression magnitudes above 1-fold (A), 2-fold (B), and 4-fold (C) difference in expression are shown. Full article ">Figure 4
Gene Ontology terms (GO-terms) functional enrichment analysis of DEPs for all six comparisons (A–F) between the four treatment sample groups. Treatment names are as described in <a href="#applsci-14-10061-t001" class="html-table">Table 1</a>. GO-terms are presented as bar-plots on the left side of the figure, and using g:Profiler-type table outputs on the right side of the figure, respectively. The bar-plot panels on the left present quantitative data (counts) regarding up- and down-regulated DEPs, categorized from top to bottom according to significance (smaller to higher adjusted p-values), and irrespective classification of DEPs in main functional categories. The table panels on the right present the same GO-terms further categorized into three functional groups: biological process (BP), cellular component (CC), and molecular function (MF). GO-term IDs and sizes are also presented along with p-value significance scores. Full article ">

23 pages, 3321 KiB

Open AccessArticle

A Survey System for Artificial Intelligence-Based Painting Using Generative Adversarial Network Techniques

by Chaoyang Zhang, Xiang Li and Ming-Der Jean

Appl. Sci. 2024, 14(21), 10060; https://doi.org/10.3390/app142110060 - 4 Nov 2024

Viewed by 676

Abstract

The purpose of this paper is to construct an evaluation system for AI painting software based on generative adversarial network (GAN) technology, which optimizes the performance of the related software in terms of functionality, ease of use, system performance, and safety. The results [...] Read more.

The purpose of this paper is to construct an evaluation system for AI painting software based on generative adversarial network (GAN) technology, which optimizes the performance of the related software in terms of functionality, ease of use, system performance, and safety. The results of the questionnaires are statistically analyzed. In addition, an exploratory factor analysis was conducted to extract the data of the study, which were ultimately used to calculate the weight and importance of each index using the fuzzy hierarchical analysis method. This study constructed an evaluation system for AI painting software based on GAN technology, including 16 indicators of functionality, 16 indicators of ease of use, 7 indicators of system performance, and 8 indicators of safety, respectively, whose alpha coefficients were 0.882, 0.962, 0.932, 0.932, and 0.932, respectively. In addition, the accumulated explanatory variances of their coefficients were 84.405%, 84.897%, 84.013%, 72.606%, 73.013%, and 72.606%, respectively. It is clear that the items included in each of the indicators are homogeneous, with a high degree of internal consistency. This paper suggests that the development of AI painting software focusing on functionality, ease of use, system performance, and safety can enhance the market competitiveness of the software. Full article

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18 pages, 12931 KiB

Open AccessArticle

H₂ Optimization of a New Type of Tuned Lever Inerter-like Mass Damper (TLIMD) for Attenuating Structure Vibrations

by Kai Xu, Weiwei Wang, Hui Liang, Aifeng Liu, Jianmin Yang, Jingzhou Gao and Bei Chen

Appl. Sci. 2024, 14(21), 10059; https://doi.org/10.3390/app142110059 - 4 Nov 2024

Viewed by 557

Abstract

The lever or the lever-type mechanism can achieve an inertia amplification effect by appropriately calibrating its structural configuration, and it is also proven to be one of the most cost-effective solution for the inerter realization compared with other mechanical devices. Benefitting from this [...] Read more.

The lever or the lever-type mechanism can achieve an inertia amplification effect by appropriately calibrating its structural configuration, and it is also proven to be one of the most cost-effective solution for the inerter realization compared with other mechanical devices. Benefitting from this property, the present paper adopted a new type of tuned lever inerter-like mass damper (TLIMD) for attenuating stochastic load-induced structure dynamic responses. A set of closed-form formulae for the TLIMD optimal parameters are developed by the use of H₂ norm optimization criterion, wherein the structure’s inherent damping is explicitly accounted for. It is theoretically demonstrated that the TLIMD optimal parameters are mainly dominated by three critical parameters, i.e., the damper mass ratio, the lever length ratio (known as the inertia amplification ratio) and also the host structural damping. The proposed formulae for the TLIMD optimization are validated through the seismic analysis, where two classic inerter-based dampers (i.e., the tuned mass damper inerter (TMDI) and the tuned inerter damper (TID)) optimized by the numerical technique are included in the discussion. It is found that the TLIMD has a superior advantage in reducing the structure responses and also exhibits stronger robustness for the detuning condition than the classic inerter-based dampers. Furthermore, the increase in the damper mass ratio and the lever length ratio can be beneficial for enhancing its performance. Full article

(This article belongs to the Special Issue Monitoring and Reducing Structural Vibrations in Civil Engineering)

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22 pages, 635 KiB

Open AccessArticle

DC-SoC: Optimizing a Blockchain Data Dissemination Model Based on Density Clustering and Social Mechanisms

by Xinhua Dong, Xiaohong Dang, Zhigang Xu, Kangze Ye, Hongmu Han and Enda Zheng

Appl. Sci. 2024, 14(21), 10058; https://doi.org/10.3390/app142110058 - 4 Nov 2024

Viewed by 694

Abstract

Due to its partially decentralized and highly scalable features, the consortium blockchain has currently overtaken other blockchain technologies as the one most frequently used and studied across various industries. However, performance issues such as low transaction efficiency and redundant communication processes continue to [...] Read more.

Due to its partially decentralized and highly scalable features, the consortium blockchain has currently overtaken other blockchain technologies as the one most frequently used and studied across various industries. However, performance issues such as low transaction efficiency and redundant communication processes continue to hinder the development of consortium blockchains. In the Hyperledger Fabric consortium blockchain system, transaction efficiency is largely influenced by the consensus protocol and broadcast protocol. This paper introduces a novel consortium blockchain network model, DC-SoC, focused on optimizing broadcast protocols. By incorporating the concept of density clustering, a stable propagation structure is established for the blockchain network, thus optimizing data dissemination in the Gossip protocol. Additionally, the concept of social networks is integrated, using trustworthiness scores and economic incentives to evaluate node security. The experimental results demonstrate that when DC-SoC is applied in a large-scale consortium blockchain environment, it significantly improves communication performance between nodes and ensures transmission reliability. Full article

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17 pages, 847 KiB

Open AccessReview

A Comprehensive Review of Sensor-Based Smart Building Monitoring and Data Gathering Techniques

by Ingrida Lavrinovica, Janis Judvaitis, Dans Laksis, Marija Skromule and Kaspars Ozols

Appl. Sci. 2024, 14(21), 10057; https://doi.org/10.3390/app142110057 - 4 Nov 2024

Viewed by 1788

Abstract

In an era where buildings are increasingly becoming multifaceted entities, the paradigm of smart buildings has witnessed significant evolution. This advancement integrates sophisticated communication technologies, the Internet of Things (IoT), artificial intelligence (AI), and data analytics. Intending to design an effective smart building [...] Read more.

In an era where buildings are increasingly becoming multifaceted entities, the paradigm of smart buildings has witnessed significant evolution. This advancement integrates sophisticated communication technologies, the Internet of Things (IoT), artificial intelligence (AI), and data analytics. Intending to design an effective smart building monitoring system, this research paper explores and compares various solutions for measuring building parameters by identifying a broad spectrum of review articles considering building occupant behavior, sensor deployment, and implementation complexity. The objective of our paper is to compile diverse information on various sensors used for monitoring building conditions and provide a comprehensive overview of data structuring and processing, all within a single article. Additionally, this paper addresses the challenges of combining data from decentralized systems and the need for managerial tools to optimize user experiences. The findings contribute to the advancement of smart building management, offering valuable insights for improving building performance and user experience as well as evaluating future research directions in this field. This review is designed to serve as an introduction for anyone venturing into the field of building monitoring. Full article

(This article belongs to the Special Issue Digital Twin and IoT)

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21 pages, 32088 KiB

Open AccessArticle

Development and Validation of Concept of Innovative Method of Computer-Aided Monitoring and Diagnostics of Machine Components

by Krzysztof Herbuś, Andrzej Dymarek, Piotr Ociepka, Tomasz Dzitkowski, Cezary Grabowik, Kamil Szewerda, Katarzyna Białas and Zbigniew Monica

Appl. Sci. 2024, 14(21), 10056; https://doi.org/10.3390/app142110056 - 4 Nov 2024

Viewed by 815

Abstract

The monitoring and diagnostic system has been suggested as a non-destructive diagnostic method. The structure and operation of the suggested system can be described by the concept of digital shadow (DS). One of the main DS subsystems is a set of sensors properly [...] Read more.

The monitoring and diagnostic system has been suggested as a non-destructive diagnostic method. The structure and operation of the suggested system can be described by the concept of digital shadow (DS). One of the main DS subsystems is a set of sensors properly placed on the monitored object and coupled with a discrete data processing model created in Matlab/Simulink. The discrete model, as another important DS subsystem of the monitored facility, transfers information about its technical condition to the operator based on data recorded by the sensor system. The digital monitoring model processes the recorded data in the form of the object’s response to actions caused by its operating conditions. This work formalized a mathematical model determining the coupling of the digital model with the sensors placed on the monitored object. The formulated method using DS, due to its sensitivity, enables the detection of the damage in the object at an early stage. The tests allowed for detecting the regularities enabling the determination of the area of damage to the shaft and its size. Full article

(This article belongs to the Special Issue The Advances and Applications of Non-destructive Evaluation)

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19 pages, 3586 KiB

Open AccessArticle

Effect of Stimulus Regularities on Eye Movement Characteristics

by Bilyana Genova, Nadejda Bocheva and Ivan Hristov

Appl. Sci. 2024, 14(21), 10055; https://doi.org/10.3390/app142110055 - 4 Nov 2024

Viewed by 657

Abstract

Humans have the unique ability to discern spatial and temporal regularities in their surroundings. However, the effect of learning these regularities on eye movement characteristics has not been studied enough. In the present study, we investigated the effect of the frequency of occurrence [...] Read more.

Humans have the unique ability to discern spatial and temporal regularities in their surroundings. However, the effect of learning these regularities on eye movement characteristics has not been studied enough. In the present study, we investigated the effect of the frequency of occurrence and the presence of common chunks in visual images on eye movement characteristics like the fixation duration, saccade amplitude and number, and gaze number across sequential experimental epochs. The participants had to discriminate the patterns presented in pairs as the same or different. The order of pairs was repeated six times. Our results show an increase in fixation duration and a decrease in saccade amplitude in the sequential epochs, suggesting a transition from ambient to focal information processing as participants acquire knowledge. This transition indicates deeper cognitive engagement and extended analysis of the stimulus information. Interestingly, contrary to our expectations, the saccade number increased, and the gaze number decreased. These unexpected results might imply a reduction in the memory load and a narrowing of attentional focus when the relevant stimulus characteristics are already determined. Full article

(This article belongs to the Special Issue Latest Research on Eye Tracking Applications)

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24 pages, 1200 KiB

Open AccessArticle

Exploring Core Knowledge in Interdisciplinary Research: Insights from Topic Modeling Analysis

by Shuangyan Wu, Mixin Lin, Mengxiao Ji and Ting Wang

Appl. Sci. 2024, 14(21), 10054; https://doi.org/10.3390/app142110054 - 4 Nov 2024

Viewed by 1909

Abstract

Although interdisciplinary research has garnered extensive attention in academia, its core knowledge structure has yet to be systematically explored. To address this gap, this study aims to uncover the underlying core knowledge topics within interdisciplinary research, enabling researchers to gain a deeper understanding [...] Read more.

Although interdisciplinary research has garnered extensive attention in academia, its core knowledge structure has yet to be systematically explored. To address this gap, this study aims to uncover the underlying core knowledge topics within interdisciplinary research, enabling researchers to gain a deeper understanding of the knowledge framework, improve research efficiency, and offer insights for future inquiries. Based on the Web of Science (WoS) database, this study collected 153 highly cited papers and employed the LDA topic model to identify latent topics and extract the knowledge structure within interdisciplinary research. The findings indicate that the core knowledge topics of interdisciplinary research can be categorized into four major areas: the knowledge framework and social impact of interdisciplinary research, multidisciplinary approaches in cancer treatment and patient care, Covid-19 multidisciplinary care and rehabilitation, and multidisciplinary AI and optimization in industrial applications. Moreover, the study reveals that AI-related interdisciplinary research topics are rapidly emerging. Through an in-depth analysis of these topics, the study discusses potential future directions for interdisciplinary research, including the cultivation and development of interdisciplinary talent, evaluation systems and policy support for interdisciplinary research, international cooperation and interdisciplinary globalization, and AI and interdisciplinary research optimization. This study not only uncovers the core knowledge structure of interdisciplinary research but also demonstrates the effectiveness of the LDA topic model as a data mining tool for revealing key topics and trends, providing practical tools for future research. However, this study has two main limitations: the time lag of highly cited papers and the dynamic evolution of interdisciplinary research. Future research should address these limitations to further enhance the understanding of interdisciplinary research. Full article

(This article belongs to the Special Issue Data and Text Mining: New Approaches, Achievements and Applications)

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13 pages, 1972 KiB

Open AccessArticle

FaceReader Insights into the Emotional Response of Douro Wines

by Catarina Marques and Alice Vilela

Appl. Sci. 2024, 14(21), 10053; https://doi.org/10.3390/app142110053 - 4 Nov 2024

Viewed by 920

Abstract

Understanding consumers’ emotional responses to wine is essential for improving marketing strategies and product development. Emotions play a pivotal role in shaping consumer preferences. This study investigates the emotional reactions elicited by different types of Douro wines (white, red, and Port) through facial [...] Read more.

Understanding consumers’ emotional responses to wine is essential for improving marketing strategies and product development. Emotions play a pivotal role in shaping consumer preferences. This study investigates the emotional reactions elicited by different types of Douro wines (white, red, and Port) through facial expression analysis using FaceReader software, version 9.0 (Noldus Information Technology, Wageningen, The Netherlands). A total of 80 participants tasted six wine samples, and their facial expressions were recorded and analyzed. FaceReader quantified the intensity of emotions such as happiness, sadness, anger, surprise, fear, and disgust. Arousal levels were also assessed. The results were analyzed through principal component analysis (PCA) to identify patterns and groupings based on emotional responses. White wines evoked more sadness due to their acidity, while red wines were associated with lower levels of sadness and greater comfort. Port wines elicited surprise, probably due to their sweet and fortified nature. Additionally, female participants showed consistently higher arousal levels than males across all wine types. The study highlights distinct emotional profiles for each type of wine and suggests that demographic factors, such as gender, influence emotional responses. These insights can inform targeted marketing and enhance the consumer experience through better alignment of wine characteristics with emotional engagement. Full article

(This article belongs to the Special Issue Holistic Approaches in Sensory Research on Food and Non-food Products Using New Techniques and Digital Tools)

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26 pages, 12162 KiB

Open AccessArticle

Hybrid Renewable Systems for Small Energy Communities: What Is the Best Solution?

by João S. T. Coelho, Modesto Pérez-Sánchez, Oscar E. Coronado-Hernández, Francisco-Javier Sánchez-Romero, Aonghus McNabola and Helena M. Ramos

Appl. Sci. 2024, 14(21), 10052; https://doi.org/10.3390/app142110052 - 4 Nov 2024

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Abstract

This research developed smart integrated hybrid renewable systems for small energy communities and applied them to a real system to achieve energy self-sufficiency and promote sustainable decentralized energy generation. It compares stand-alone (SA) and grid-connected (GC) configurations using a developed optimized mathematical model [...] Read more.

This research developed smart integrated hybrid renewable systems for small energy communities and applied them to a real system to achieve energy self-sufficiency and promote sustainable decentralized energy generation. It compares stand-alone (SA) and grid-connected (GC) configurations using a developed optimized mathematical model and data-driven optimization, with economic analysis of various renewable combinations (PV, Wind, PHS, BESS, and Grid) to search for the optimal solution. Four cases were developed: two stand-alone (SA1: PV + Wind + PHS, SA2: PV + Wind + PHS + BESS) and two grid-connected (GC1: PV + PHS + Grid, GC2: Wind + PHS + Grid). GC2 shows the most economical with stable cash flow (−€123.2 annually), low CO₂ costs (€367.2), and 91.7% of grid independence, requiring 125 kW of installed power. While GC options had lower initial investments (between €157k to €205k), the SA configurations provided lower levelized costs of energy (LCOE) ranging from €0.039 to €0.044/kWh. The integration of pumped hydropower storage enhances energy independence, supporting peak loads for up to two days with a storage capacity of 2.17 MWh. Full article

(This article belongs to the Special Issue Challenges and Opportunities of Microgrids)

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Appl. Sci., Volume 14, Issue 21 (November-1 2024) – 464 articles

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