bluuebunny/crossref_metadata_2025 huggingface dataset:
Optimization and Chemical Characterization of Extracts Obtained from Ferula persica var. latisecta Aerial Parts and Roots and Their Neuroprotective Evaluation
Authors: Mohammadnezhad Pouya , Valdés Alberto , Cifuentes Alejandro
Published: December 2024

Background/Objectives: The genus Ferula has been traditionally used for the treatment of various illnesses, but the potential of Ferula persica var. latisecta against different Alzheimer’s disease (AD) hallmarks has never been achieved. Methods: In this work, a pressurized liquid extraction (PLE) method was optimized to extract F. persica L. aerial parts and roots. Four different solvents (water, ethanol, ethyl acetate (EtAc), and cyclopentyl methyl ether (CPME)) were first tested, and the extraction yield, total phenolic content, reactive oxygen species scavenging capacity, and acetylcholinesterase (AChE) inhibition activity were evaluated. Results: The results indicated that EtAc and CPME were the best solvents to be used, with the results obtained from the aerial parts being better than those obtained from the root samples. Thereafter, the PLE method was further optimized by combining these solvents in different percentages (100% EtAc, 100% CPME, and 50:50% (v/v) EtAc:CPME) and temperatures (50, 115, and 180 °C). Response surface methodology was then applied to analyze the data, and two optimum extraction conditions were obtained: EtAc:CPME (79:21%) at 180 °C for the aerial parts and 100% CPME at 180 °C for the roots. At these conditions, the total flavonoid content (TFC) and the inhibitory capacities against butyrylcholinesterase (BChE) and lipoxygenase (LOX) enzymes were also evaluated, indicating that the aerial part extracts had higher TFC and LOX inhibitory capacity than the root extracts but lower activity against BChE. The comprehensive LC/GC-MS chemical characterization allowed for the tentative identification of 222 compounds belonging to 66 chemical subclasses, the abundancies of which widely varied depending on the matrix and the extraction conditions used. Conclusions: The results obtained together with the application of advanced statistical analysis and molecular docking simulations suggested several sesquiterpenoids, such as selina-3,7(11)-diene, guaiol acetate, α-cyperone, and farnesyl acetate, as the molecules responsible of the in vitro results observed, with good neuroprotective potential against AD.
Design, Synthesis, Antimicrobial Activity, and Molecular Docking of Novel Thiazoles, Pyrazoles, 1,3-Thiazepinones, and 1,2,4-Triazolopyrimidines Derived from Quinoline-Pyrido[2,3-d] Pyrimidinones
Authors: Abu-Hashem Ameen Ali , Al-Hussain Sami A.
Published: December 2024

Background: Recently, pyrido[2,3-d] pyrimidine, triazolopyrimidine, thiazolopyrimidine, quinoline, and pyrazole derivatives have gained attention due to their diverse biological activities, including antimicrobial, antioxidant, antitubercular, antitumor, anti-inflammatory, and antiviral effects. Objective: The synthesis of new heterocyclic compounds including 5-quinoline-pyrido[2,3-d] pyrimidinone (1–2, 4, 6–7), 6-quinoline-pyrido[2,3-d]thiazolo[3,2-a]pyrimidinone (3, 5, 8–10), 1,2,4-triazole-6-quinoline-pyrido[2,3-d]thiazolo[3,2-a]pyrimidinone (11–13), and pyrido[2,3-d]thiazolo[3,2-a]pyrimidine-ethyl-(pyridine)-9-thiaazabenzo[cd]azulenone (14) derivatives was performed with high yields while evaluating antimicrobial activities. Methods: A new series of quinoline-pyrido[2,3-d]thiazolo[3,2-a]pyrimidine derivatives were prepared using a modern style and advanced technology, resulting in high yields of these new compounds. Various reagents were utilized, specifically tailored to the production needs of each compound, through reactions that included alkylation, addition, condensation, acylation, the formation of Schiff bases, and intramolecular cyclization. Results: The chemical structures of the new compounds were determined using spectroscopy analyses, including IR, NMR, and MS, achieving good yields ranging from 68% to 90% under mild conditions in a regular system. All compounds were tested for in vitro antimicrobial activity and compared to standard drugs, specifically cefotaxime sodium and nystatin. The results showed that compounds 10 to 14 exhibited excellent antimicrobial activity, with a minimum inhibitory concentration (MIC) of 1 to 5 µmol/mL, compared to that of the standard drugs, which had MIC values of 1 to 3 µmol/mL. Furthermore, molecular docking studies were conducted to explore the interactions of specific compounds with antimicrobial target proteins. The findings revealed that compounds 10 to 14 displayed significant binding energies, with ΔG values ranging from −7.20 to −11.70 kcal/mol, indicating effective binding to the active sites of antimicrobial protein receptors. Conclusions: The SAR study confirmed a relationship between antimicrobial activity and the tested compounds. Molecular docking demonstrated that compounds 10, 11, 12, 13, and 14 exhibited significant binding energy, effectively interacting with the active sites of antimicrobial protein receptors. This consistent finding supports that these new compounds’ practical and theoretical studies align regarding their antimicrobial activity.
Long-Term Conservation Agriculture Improves Soil Quality in Sloped Farmland Planting Systems
Authors: Li Hongying , Tang Jun , Wang Jing , Qiao Jun , Zhu Ningyuan
Published: December 2024

Conservation agriculture practices (CAs) are important under the increasingly serious soil quality degradation of sloping farmlands worldwide. However, little is known about how the long-term application of CAs influences soil quality at different slope positions. We conducted field experiments for a watershed sloping farmland’s mainstream planting systems in the Three Gorges Reservoir area of China. Orchard plots were treated with a conventional citrus planting pattern (C-CK), citrus intercropped with white clover (WC), citrus orchard soil mulched with straw (SM) and citrus intercropped with Hemerocallis flava contour hedgerows (HF). Crop field plots were treated with a conventional wheat–peanut rotation (W-CK), a wheat–peanut rotation intercropped with Toona sinensis contour hedgerows (TS), a wheat–peanut rotation intercropped with alfalfa contour hedgerows (AF) and a ryegrass–sesame rotation (RS). We collected soil samples from the plots at the upper, middle and lower slope positions and measured their soil properties after a nine-year experiment. We found that (1) CAs improved the soil properties at the three slope positions; (2) the effect of the CAs on the soil properties was more significant than that on the slope position; and (3) the soil quality index at the upper, middle and lower slope positions increased by 29.9%, 45.8% and 33.3%, respectively, for WC; 48.7%, 39.5% and 27.1%, respectively, for SM; and 21.7%, 25.5% and 21.6%, respectively, for HF compared to C-CK; as well as 18.7%, 23.7% and 20.4%, respectively, for TS; 16.9%, 18.6% and 16.5%, respectively, for AF; and 16.1%, 13.0% and 13.9%, respectively, for RS compared to W-CK. These findings suggest that long-term CA application enhances the soil quality of the slope position, of which SM and TS applied to orchards and crop fields, respectively, are the most effective.
Thermo-Responsive and Electroconductive Nano Au-PNiPAAm Hydrogel Nanocomposites: Influence of Synthesis Method and Nanoparticle Shape on Physicochemical Properties
Authors: Radojković Nikolina , Spasojević Jelena , Kačarević-Popović Zorica , Stamenović Una , Vodnik Vesna , Roglić Goran , Radosavljević Aleksandra
Published: December 2024

Hydrogel nanocomposites that respond to external stimuli and possess switchable electrical properties are considered as emerging materials with potential uses in electrical, electrochemical, and biological devices. This work reports the synthesis and characterization of thermo-responsive and electroconductive hydrogel nanocomposites based on poly(N-isopropylacrylamide) (PNiPAAm) and gold nanoparticles (nanospheres—AuNPs and nanorods—AuNRs) using two different synthetic techniques. Method I involved γ-irradiation-induced crosslinking of a polymer matrix (hydrogel), followed by radiolytic in situ formation of gold nanoparticles, while Method II included the chemical synthesis of nanoparticles, followed by radiolytic formation of a polymer matrix around the gold nanoparticles. UV–Vis spectral studies revealed the presence of local surface plasmon resonance (LSPR) bands characteristic of nanoparticles of different shapes, confirming their formation and stability inside the polymer matrix. Morphological, structural, and physicochemical analyses indicated the existence of a stable porous polymer matrix, the formation of nanoparticles with a face-centered cubic structure, increased swelling capacity, and a slightly higher volume phase transition temperature (VPTT) for the hydrogel nanocomposites. Comparative electrochemical impedance spectroscopy (EIS) showed an increase in conductivity for the nano Au-PNiPAAm hydrogel nanocomposites compared to the PNiPAAm hydrogel, with a considerable rise detected above the VPTT. By reverting to room temperature, the conductivity decreased, indicating that the investigated hydrogel nanocomposites exhibited a remarkable reversible “on–off” thermo-switchable mechanism. The highest conductivity was observed for the sample with rod-shaped gold nanoparticles. The research findings, which include optical, structural, morphological, and physicochemical characterization, evaluation of the efficiency of the chosen synthesis methods, and conductivity testing, provide a starting point for future research on the given nanocomposite materials with integrated multifunctionality.
Liturgical Gift or Theological Burden? Teenagers and Ecumenical Liturgical Exchange Events
Authors: Cowan Nelson Robert , Andrews Emily Snider
Published: December 2024

Assumptions about the preferences of teenagers in corporate worship regarding format, style, musical selections, and other experiences abound. Recognizing that teenagers are far from homogenous, we sought to listen deeply to how they process and define their experiences of worship, particularly through the lens of encountering liturgical difference. Our research team spent one week with approximately 35 highly religious, majority-Evangelical teenagers at Animate 2023 in Birmingham, Alabama—a summer camp with an emphasis in worship and the arts. Based on data from individual interviews and focus groups, this paper articulates some of our findings—namely that these highly devoted teenage worshipers demonstrate liturgical curiosity, delight in their own agency, and often desire to adopt practices that are foreign to them, even when some of those elements are deemed “weird”. The lived experiences of young people are often missing from conversations about their liturgical practices in both the Church and academy. While this study is not generalizable, it offers a micro glimpse into one worship arts camp, aiming to provide tangible data points to address this lacuna.
An Old Uighur balividhi Fragment Unearthed from the Northern Grottoes of Dūnhuáng
Authors: Mirkamal Aydar , Li Xiaonan
Published: December 2024

Photographs of the recto side of the manuscript fragment B121:38 in Old Uighur, which was excavated from the northern section of the Dūnhuáng Mògāo Caves, were published in the second volume of The Northern Grottoes of Mògāo Caves. Because the verso side, which contains essential information, remains unpublished—despite the publication of the recto—the manuscript’s typology cannot be fully comprehended, and it has consequently not garnered substantial scholarly attention. Through site investigation, transcription, English translation, detailed annotation, and comparative analysis with parallel Tibetan texts, B121:38 is confirmed to be a balividhi fragment of Tantric Buddhist literature. This fragment comprises three parts: praise for the five ḍākas, a transference of merits, and a mantra. The findings provide compelling evidence of the prominence of Tibetan Tantrism among Old Uighurs.
Optimal Synthesis of Five-Bar Linkage Based on Singularity-Free Workspaces with Predefined Shapes
Authors: Erwin-Christian Lovasz , Valentin Ciupe , Tivadar Demjen , Alexandru Oarcea , Elida-Gabriela Tulcan , Melania-Olivia Sandu
Published: December 2024

The five-bar linkage, used in the form of a planar manipulator, benefits from easy controllability and relatively simple kinematic structures, which mean that it can be used in several applications in robotics, rehabilitation, and haptic devices, etc. This paper proposes an optimal synthesis method for a symmetrical five-bar linkage of type 5-RRRRR, with a singularity-free dexterous workspace, based on workspaces with predefined shapes, like squares, rectangles, triangles, circles, and ellipses. The synthesis conditions, to avoid singularities, are given as inequations, which can be further substituted with a system of equations, by introducing the supraunitary coefficient, k. The analytical solutions of the resulting system of equations enable the computation of the link lengths of the five-bar linkage. The optimization method provides the optimal value of the supraunitary coefficient, in order to obtain a maximum value for the minimum input transmission angle and a minimum value for the manipulator size. In this paper, the authors present an analytical approach to the optimal synthesis of a symmetrical five-bar linkage for different shapes of workspace, with the same surface and coordinates in terms of the mass center, as well as the resulting link lengths. In regard to the numerical examples, the authors considered and compared performance indices, such as manipulability, the condition number, and stiffness. The considered examples showed that an equilateral triangle-shaped workspace achieved higher global manipulability, a square-shaped workspace achieved higher global dexterity and the minimum input transmission angle, and circular workspaces achieved the highest mean stiffness and total surface size. It was observed that the synthesis method generates structures that are well-suited to singularity-free dexterous workspaces, with nonzero stiffness values.
Implications of Pulse Frequency in Terrestrial Laser Scanning on Forest Point Cloud Quality and Individual Tree Structural Metrics
Authors: Verhelst Tom E. , Calders Kim , Burt Andrew , Demol Miro , D’hont Barbara , Nightingale Joanne , Terryn Louise , Verbeeck Hans
Published: December 2024

Terrestrial laser scanning (TLS) provides highly detailed 3D information of forest environments but is limited to small spatial scales, as data collection is time consuming compared to other remote sensing techniques. Furthermore, TLS data collection is heavily dependent on wind conditions, as the movement of trees negatively impacts the acquired data. Hardware advancements resulting in faster data acquisition times have the potential to be valuable in upscaling efforts but might impact overall data quality. In this study, we investigated the impact of the pulse repetition rate (PRR), or pulse frequency, which is the number of laser pulses emitted per second by the scanner. Increasing the PRR reduces the scan time required for a single scan but decreases the power (amplitude) of the emitted laser pulses commensurately. This trade-off could potentially impact the quality of the acquired data. We used a RIEGL VZ400i laser scanner to test the impact of different PRR settings on the point cloud quality and derived tree structural metrics from individual tree point clouds (diameter, tree height, crown projected area) as well as quantitative structure models (total branch length, tree volume). We investigated this impact across five field plots of different forest complexity and canopy density for three different PRR settings (300, 600 and 1200 kHz). The scan time for a single scan was 180, 90 and 45 s for 300, 600 and 1200 kHz, respectively. Differences among the raw acquired scans from different PRR replicates were largely removed by several necessary data processing steps, notably the removal of uncertain points with a low reflectance attribute. We found strong agreement between the individual tree structural metrics derived from each of the PRR replicates, independent of the forest complexity. This was the case for both point cloud-based metrics and those derived from quantitative structural models (QSMs). The results demonstrate that the PRR in high-end TLS instruments can be increased for data collection with negligible impact on a selection of derived structural metrics that are commonly used in the context of aboveground biomass estimation.
Calculating the Optimal Point Cloud Density for Airborne LiDAR Landslide Investigation: An Adaptive Approach
Authors: Liao Zeyuan , Dong Xiujun , He Qiulin
Published: December 2024

Ensuring that ground point density after raw point cloud processing meets the accuracy requirements for subsequent DEM construction represents a challenge for field operators during airborne LiDAR data acquisition. In this study, we propose a method to quantify DEM quality by combining the RMSE of elevation and terrain complexity, analyzing the DEM quality error curves constructed with different point cloud densities by a discrete difference peak-seeking method, to determine the optimal ground point density, and then constructing an ICP-NN algorithm for predicting the collected point cloud density. After analysis of DEM quality at eight point cloud dilution levels, the optimal ground point cloud densities were determined to be 2.43 pts/m2 (0.2 m resolution), 2.08 pts/m2 (1 m and 0.5 m resolution), and 1.84 pts/m2 (2 m resolution). Using the obtained optimal ground point densities, survey area slopes, canopy density, and elevation differences as eigenvalues, the ICP-NN model can be used to directly predict the collected point cloud density intervals in other regions, and the model has interval lengths ranging from 36 to 70.33 pts/m2 at 5 CLs. This method solves the problem of determining point cloud density in landslide surveys using airborne LiDAR and provides direct guidance for practical applications.
Thermal Deformation Analysis of a Star Camera to Ensure Its High Attitude Measurement Accuracy in Orbit
Authors: Jiang Fan , Wang Lei , Deng Huaxia , Zhu Lei , Kong Dezhu , Guan Hongyu , Liu Jinguo , Wang Zhongsu
Published: December 2024

With the continuous advancement of high-resolution satellite technology, the impact of thermal deformation on the performance of star cameras is becoming more significant, particularly in relation to installation conditions and orbital environments. To address this challenge, an in-depth investigation of the thermal design of a star camera is conducted in this study. The thermal deformation of this camera is evaluated systematically through simulation analysis, thermal balance tests, and on-orbit temperature measurements. In addition, a simulation analysis is used to identify and quantitatively evaluate the thermal deformation error sources that affect the spatial attitude measurement accuracy of the star camera. The results indicate that thermal deformations of the optical system, the mounting surface of the star camera, and the support significantly impact on-orbit measurement accuracy. Ultimately, the limit error attributable to on-orbit thermal deformation is determined to be 0.62″. In the thermal balance experiments, the maximum absolute difference between the test results and the thermal simulation analysis results is under 1.8 °C. Additionally, analysis of the orbital temperature data reveals that the maximum absolute difference between the orbital results and the thermal simulation results is 1.18 °C, while the attitude accuracy of the star sensor is better than 0.54″. These findings validate the effectiveness of the thermal design and the accuracy of the thermal simulation analysis. The analysis of error sources presented in this paper offers crucial insights for effectively controlling the thermal deformation errors of star cameras and lays the groundwork for optimizing overall thermal design.
Two-Dimensional Directions Determination for GNSS Spoofing Source Based on MEMS-Based Dual-GNSS/INS Integration
Authors: Zhang Chengzhong , Wang Dingjie , Wu Jie
Published: December 2024

Satellite navigation spoofing is a major challenge in the field of satellite/inertial integrated navigation security. To effectively enhance the anti-spoofing capability of a low-cost GNSS/MEMS-SINS integrated navigation system, this paper proposes a method integrating a dual-antenna global navigation satellite system (GNSS) and a micro-inertial measurement unit (MIMU) to determine the two-dimensional directions of spoofing signal sources. The proposed method evaluates whether the single-difference carrier-phase measurements conform to the corresponding directions given in ephemeris files and employs micro-inertial navigation technology to determine the two-dimensional directions of the signal source. Based on a set of short-baseline dual-station measurements, the accuracy of the proposed method in determining the two-dimensional azimuths of satellites in synchronous orbits is verified, and the deviation from the real value is evaluated. The experimental results show that the proposed method can effectively identify the spoofed satellite signals while providing high-precision direction information at three different distances: 100 m, 10 km, and 36,000 km. The two-dimensional angle errors do not exceed 0.2 rad, 0.05 rad, and 0.01 rad, respectively.
Reliable and Effective Stereo Matching for Underwater Scenes
Authors: Zhu Lvwei , Gao Ying , Zhang Jiankai , Li Yongqing , Li Xueying
Published: December 2024

Stereo matching plays a vital role in underwater environments, where accurate depth estimation is crucial for applications such as robotics and marine exploration. However, underwater imaging presents significant challenges, including noise, blurriness, and optical distortions that hinder effective stereo matching. This study develops two specialized stereo matching networks: UWNet and its lightweight counterpart, Fast-UWNet. UWNet utilizes self- and cross-attention mechanisms alongside an adaptive 1D-2D cross-search to enhance cost volume representation and refine disparity estimation through a cascaded update module, effectively addressing underwater imaging challenges. Due to the need for timely responses in underwater operations by robots and other devices, real-time processing speed is critical for task completion. Fast-UWNet addresses this challenge by prioritizing efficiency, eliminating the reliance on the time-consuming recurrent updates commonly used in traditional methods. Instead, it directly converts the cost volume into a set of disparity candidates and their associated confidence scores. Adaptive interpolation, guided by content and confidence information, refines the cost volume to produce the final accurate disparity. This streamlined approach achieves an impressive inference speed of 0.02 s per image. Comprehensive tests conducted in diverse underwater settings demonstrate the effectiveness of both networks, showcasing their ability to achieve reliable depth perception.
Study on Calibration Tests for Interface-Type Earth Pressure Cell Based on Matching Error Analysis
Authors: Li Mingyu , Zhu Longwei , Shu Jicheng , Lu Zhenzhen , Liu Yunlong
Published: December 2024

The stress status of a soil pressure cell placed in soil is very different from its stress state in a uniform fluid medium. The use of the calibration coefficient provided by the soil pressure cell manufacturer will produce a large error. In order to improve the measurement accuracy of the interface-type earth pressure cell placed in soil, this paper focuses on a single-membrane resistive earth pressure cell installed on the surface of a structure, analyzing the influence of loading and unloading cycles, the thickness and particle size of the sand filling, and the depth of the earth pressure cell inserted in the structure on the calibration curve and matching error, which were analyzed through calibration tests. The results show that when the sand filling thickness is less than D (D is the diameter of the earth pressure cell), the calibration curve is unstable in relation to the increase in the number of loading and unloading cycles, which will cause the sand calibration coefficient used for stress conversion to not be used normally. When the sand filling thickness in the calibration bucket increases from 0.285D to 5D, the absolute value of the matching error first decreases and then increases, such that the optimal sand filling thickness is 3D. The output of the earth pressure cell increases with the decrease in sand particle size under the same load, and there is a significant difference between the theoretical calculation value and the experimental value of the matching error; aiming at this difference, an empirical formula is derived to reflect the ratio of the diameter of the induction diaphragm of the earth pressure cell to the maximum particle size of the sand filling. When the depth of the earth pressure cell inserted in the structure is “0”, the sensing surface is flush with the structure and the absolute value of the matching error is the smallest. Changes in the horizontal placement of the soil pressure cell in the calibration bucket result in significant differences in both the output and hysteresis of the calibration curve. To improve the measurement accuracy of soil pressure cells in scaled tests for applications such as in the retaining walls of excavation pits, tunnel outer surfaces, pile tops, pile ends, and soil pressure measurements in soil, calibration of the soil pressure cells is required before testing. Due to the considerable difference in the stress states of the soil pressure cell between granular media and uniform fluid media, calibration in soil is essential. During in-soil calibration, factors such as cyclic loading and unloading, soil compression, sand thickness and particle size, and the placement of the soil pressure cell all affect the calibration results. This paper primarily investigates the influence of these factors on the calibration curve and matching error. This study found that, as the sand thickness increases, the matching error decreases initially and then increases.
Dual-Wavelength On-Chip Integrated Metalens for Epi-Fluorescence Single-Molecule Sensing
Authors: Barulina Elena , Nguyen Dang Du , Shuklin Fedor , Podobrii Mikhail , Novikov Sergey , Chernov Alexander , Kim Inki , Barulin Aleksandr
Published: December 2024

Single-molecule fluorescence spectroscopy offers unique capabilities for the low-concentration sensing and probing of molecular dynmics. However, employing such a methodology for versatile sensing and diagnostics under point-of-care demands device miniaturization to lab-on-a-chip size. In this study, we numerically design metalenses with high numerical aperture (NA = 1.1), which are composed of silicon nitride nanostructures deposited on a waveguide and can selectively focus guided light into an aqueous solution at two wavelengths of interest in the spectral range of 500–780 nm. Despite the severe chromatic focal shift in the lateral directions owing to the wavelength-dependent propagation constant in a waveguide, segmented on-chip metalenses provide perfectly overlapping focal volumes that meet the requirements for epi-fluorescence light collection. We demonstrate that the molecule detection efficiencies of metalenses designed for the excitation and emission wavelengths of ATTO 490LS, Alexa 555, and APC-Cy7 tandem fluorophores are sufficient to collect several thousand photons per second per molecule at modest excitation rate constants. Such sensitivity provides reliable diffusion fluorescence correlation spectroscopy analysis of single molecules on a chip to extract their concentration and diffusion properties in the nanomolar range. Achromatic on-chip metalenses open new avenues for developing ultra-compact and sensitive devices for precision medicine and environmental monitoring.
Discrete Event System Specification for IoT Applications
Authors: Alavi Fazel Iman , Wainer Gabriel
Published: December 2024

The Internet of Things (IoT) has emerged as a transformative technology with a variety of applications across various industries. However, the development of IoT systems is hindered by challenges such as interoperability, system complexity, and the need for streamlined development and maintenance processes. In this study, we introduce a robust architecture grounded in discrete event system specification (DEVS) as a model-driven development solution to overcome these obstacles. Our proposed architecture utilizes the publish/subscribe paradigm, and it also adds to the robustness of the proposed solution with the incorporation of the Brooks–Iyengar algorithm to enhance fault tolerance against unreliable sensor readings. We detail the DEVS specification that is used to define this architecture and validate its effectiveness through a detailed home automation case study that integrates multiple sensors and actuators.
OpticalTrust: A Sensor-to-Blockchain Framework Using Free-Space Optical Communication
Authors: Bajaj Parveen , Kataria Aman , Puri Vikram , Gupta Sachin , Min Hong
Published: December 2024

In the dynamic landscape of the tech industry, the escalating requirement for swift and secure data transmission has catalyzed innovation in integrated communication systems. Free-Space Optics (FSOs) has emerged as a promising contender in optical communications. While conventional optical fiber systems can achieve bit rates of up to 40 Gbps with proper design, they are limited primarily by electronics rather than semiconductor laser capabilities. This study presents an integrated framework that combines FSOs, blockchain technology, and sensor networks to address challenges in data transmission, security, and environmental adaptation. This study analyzes FSOs system performance through the Quality (Q) Factor and Bit Error Rate (BER), comparing systems with and without Erbium-Doped Fiber Amplifiers (EDFAs) across various bit rates (8, 12, 16, and 20 Gbps) and transmission distances (5–25 km). To enhance data security and reliability, a blockchain architecture is incorporated with smart contracts and an InterPlanetary File System (IPFS) for storing and validating results generated from FSOs simulation. Additionally, this study explores the design of sensor network models for FSOs technology by investigating how distributed sensor arrays can be theoretically integrated with FSOs systems, with testing focused on FSOs performance and blockchain implementation.
Machine Learning and Deep Learning Approaches for Arabic Sign Language Recognition: A Decade Systematic Literature Review
Authors: Alayed Asmaa
Published: December 2024

Sign language (SL) is a means of communication that is used to bridge the gap between the deaf, hearing-impaired, and others. For Arabic speakers who are hard of hearing or deaf, Arabic Sign Language (ArSL) is a form of nonverbal communication. The development of effective Arabic sign language recognition (ArSLR) tools helps facilitate this communication, especially for people who are not familiar with ArSLR. Although researchers have investigated various machine learning (ML) and deep learning (DL) methods and techniques that affect the performance of ArSLR systems, a systematic review of these methods is lacking. The objectives of this study are to present a comprehensive overview of research on ArSL recognition and present insights from previous research papers. In this study, a systematic literature review of ArSLR based on ML/DL methods and techniques published between 2014 and 2023 is conducted. Three online databases are used: Web of Science (WoS), IEEE Xplore, and Scopus. Each study has undergone the proper screening processes, which include inclusion and exclusion criteria. Throughout this systematic review, PRISMA guidelines have been appropriately followed and applied. The results of this screening are divided into two parts: analysis of all the datasets utilized in the reviewed papers, underscoring their characteristics and importance, and discussion of the ML/DL techniques’ potential and limitations. From the 56 articles included in this study, it was noticed that most of the research papers focus on fingerspelling and isolated word recognition rather than continuous sentence recognition, and the vast majority of them are vision-based approaches. The challenges remaining in the field and future research directions in this area of study are also discussed.
Kinetic Modelling of Ralstonia eutropha H16 Growth on Different Substrates
Authors: Vičević Renata , Šalić Anita , Jurinjak Tušek Ana , Zelić Bruno
Published: December 2024

Due to environmental pollution and the depletion of fossil fuels, there is growing interest in the development and use of biofuels as environmentally friendly alternatives. One of the most promising biofuels is biohydrogen, hydrogen produced through sustainable processes using microorganisms such as bacteria and algae. One of the most interesting bacteria for hydrogen production is Ralstonia eutropha H16, known for its ability to produce oxygen-tolerant hydrogenases. These enzymes play a crucial role in biohydrogen metabolism and production. The aim of this work was to determine the optimal conditions (reactor type and synthetic medium composition) for the cultivation of R. eutropha H16. The culture media contained different concentrations of fructose and glycerol (mono- or double-substrate cultivation) and the experiments were carried out in a batch reactor. The initial experiments were carried out with 4 g/L fructose or glycerol in the culture medium at pH 7, T = 30 °C, and 120 rpm. The mathematical model, consisting of the growth kinetics (described by the Monod’s model) and the corresponding mass balances, was proposed. The developed model was validated using two independent experiments with different initial substrate concentrations: 2 g/L glycerol and fructose in one medium and 4 g/L fructose and 1 g/L glycerol in the second. In order to propose the optimal cultivation procedure for future research, the mathematical model simulations were performed for different reactor types (batch, fed-batch, and continuous stirred tank reactors) and different initial substrate concentrations. The most successful experiment was the one with 4 g/L glycerol, where γX = 0.485 ± 0.001 g/L of biomass was achieved. Further calculations showed that the most biomass would be produced at higher glycerol concentrations (at γG = 6.358 g/L, γX = 1.311 g/L should be achieved after 200 h of cultivation) and when using a fed-batch reactor (γX = 0.944 g/L after 200 h of cultivation).
Impact of Conversion of the Caatinga Forest to Different Land Uses on Soil and Root Respiration Dynamics in the Brazilian Semiarid Region
Authors: Oresca Denizard , Souza Eduardo Soares de , Souza Rodolfo Marcondes Silva , Silva José Raliuson Inácio , Moura Débora Purcina de , Sampaio Everardo Valadares de Sá Barreto , Hammecker Claude , Lima José Romualdo de Sousa , Menezes Rômulo Simões Cezar , Pessoa Luiz Guilherme Medeiros , Ferrão Natache Gonçalves de Moura , Antonino Antônio Celso Dantas
Published: December 2024

The Caatinga biome has been severely devastated over the years due to the replacement of native dry forests with grassland areas in the Brazilian semiarid region. Despite this, variations in key soil quality indicators still need to be fully elucidated. We evaluated soil and root respiration dynamics in grassland (GR), agroforestry (AS), and Caatinga forest (CA) areas, during dry and rainy seasons. In situ, monthly CO2 flux (total, root, and heterotrophic respirations), soil moisture (θv), and temperature (Tsoil) were measured. Soil samples were collected every 5 cm layer up to 20 cm depth to analyze total organic carbon (TOC) and microbial activities. The highest parameter values occurred during the rainy season. Total soil respiration was highest in AS, followed by CA and then GR, with 19.3, 13.4, and 8.4 ton C ha−1 yr−1, respectively, and root respiration contributed 33.2 and 32.9% to total soil respiration in CA and AS, respectively. However, TOC concentrations and microbial activity were significantly higher in AS than in GR and similar to CA, more than compensating the C losses by respiration. Therefore, agroforestry systems have a high potential for semiarid lands because they preserve soil carbon and microbial activity comparable to Caatinga forests.
A Precise Energy Consumption Model for Computer Numerical Control Machines: A Hybrid Approach
Authors: Taphasanoğlu Saime , Cesur Muhammet Raşit , Cesur Elif
Published: December 2024

In today’s world, energy efficiency is becoming increasingly crucial, due to its impact on sustainability in production. Designing systems that consume less energy and manage resources efficiently is essential. Variations in operating speed can affect processing time, energy consumption, idle times of subsequent machines, work delays, and missed deadlines. While most studies focus on prediction parameters like cut depth and cut area to estimate the energy consumption or processing time, our approach emphasizes variations in G-code motion parameters. To enhance both precision and the adaptability of the model to all Computer Numerical Control (CNC) machines in no-load condition, we propose an intelligent hybrid model that combines physical and data-driven approaches. The first approach employs curve fitting based on the physical model, while the second utilizes deep neural network (DNN) models optimized through hyperparameter tuning. The DNN topologies we evaluated exhibit high performance, with prediction errors of less than 1% for all models. Our approach provides a more precise and comprehensive understanding of energy consumption patterns in manufacturing processes, enabling manufacturers to make informed decisions about energy utilization, cost reduction, and sustainability. Our study aims to advance the field of energy efficiency in manufacturing and contribute to a more sustainable future.
Influence of Salicylic Acid and Melatonin During Postharvest Refrigeration on Prolonging Keitt Mango Freshness
Authors: Almasoud Waleed A. , Abdel-Sattar Mahmoud , Khalifa Sobhy M. , Dawood Ahmed S. , Shahda Mohamed A. , El-Taher Ahmed M. , Haikal Amr M. , Rihan Hail Z. , Ahmed Adel F.
Published: December 2024

Mangoes are highly valued for their flavor and nutritional content, but their shelf life is limited due to quick ripening and susceptibility to microbial deterioration. The use of salicylic acid and melatonin as postharvest dipping treatments for mango fruits has the potential to significantly improve shelf life while retaining fruit quality. Salicylic acid modulates ethylene synthesis and stress reactions, whereas melatonin provides a strong antioxidant defense. These treatments might be used in postharvest management methods to minimize losses and improve mango marketability. The goal of this study is to look at the effects of salicylic acid and melatonin postharvest treatments on Keitt mango fruit in terms of physiochemical quality, enzyme activity, and ascorbic acid content during cold storage. Fruits were chilled at 5 °C ± 2 and 85 ± 2 percent humidity throughout the 2022–2023 seasons. The treatments were as follows: control (untreated fruits), salicylic acid (1 and 2 mM), and melatonin (200 and 400 mM). Data showed that dipping mango fruits in salicylic acid and melatonin under cold conditions decreased weight loss and fruit decay while improving physiochemical properties such as fruit firmness, total soluble solids (TSS%), total acidity, total sugars, enzyme activities, and ascorbic acid levels over time. In both seasons, dipping mango fruits in a melatonin solution at 200 mM followed by a salicylic acid solution at 1 mM produced the highest values for all examined parameters when compared to the control and other treatments. These findings indicate that postharvest administration of salicylic acid and melatonin can successfully increase the storability and quality of Keitt mangoes under refrigerated circumstances, providing a feasible technique for reducing postharvest losses and increasing marketability.
Between Hammer and Anvil: Sustainable Tourism and Water Quality on Cyclades Islands Between the Greek Financial Crisis (2009) and the COVID-19 (2020)
Authors: Atay Itri , Seyhan Barış , Saladié Òscar
Published: December 2024

The Cyclades Islands are significant to Greece’s economy, and their role has grown dramatically during the two crisis periods of the Greek Financial Crisis in 2009 and the COVID-19 pandemic outbreak in 2020. The crises shaped the Cyclades Islands’ tourist and water resource management due to water crisis events that took place between 2012 and 2024. The heavy dependence and emphasis on tourism revenues and less focus on water quality regulations made the situation more complex. Taking Mykonos and Santorini Islands (Greece) as a case study, this research’s main aim is to analyze hospitality stakeholders’ perceptions concerning water quality problems and reveal the ways of operation (modus operandi) that trigger shifting between stages in the lifespan of tourism destinations. Data are gathered through face-to-face interviews with hospitality stakeholders. The results show that the hospitality stakeholders believe that water quality issues exist in connection with short-term water resource management and tourism activity on the islands. Secondly, water quality issues and water shortages have begun to have a detrimental influence and negative cumulative impact on water availability and quality on the islands. These findings shed light on the critical points of the stage changes in the lifecycle and modus operandi of destination evolution.
An Evolutionary Stability Study of Zero-Carbon Transition for Shipping Enterprises Considering Dynamic Penalty and Carbon Quota Trading Mechanisms
Authors: He Zhibo , Wang Dan , Li Jiawei , Fang Wanwei , Yang Yilin , Ji Mingjun
Published: December 2024

The carbon quota trading mechanism is considered one of the most effective incentives for carbon reduction to address global climate change. Currently, the EU has adopted this mechanism to intervene in the zero-carbon transition of shipping companies. Unlike other businesses, the shipping market experiences cyclical changes and high uncertainty, with many factors and complex systems involved in the zero-carbon transition process. Research on the impact of dynamic penalty mechanisms combined with government incentive policies on the zero-carbon transition of shipping companies is relatively scarce. To explore this process under such mechanisms, an evolutionary game model of shipping companies’ zero-carbon transition considering dynamic penalties and carbon quota trading was constructed. The model analyzes the effects of factors such as carbon trading prices, emission reductions resulting from zero-carbon transition, government supervision costs, supervision intensity, subsidy values, and penalty caps on the transition process and performs a simulation analysis. The results indicate the following: (1) Under dynamic penalty mechanisms, the evolutionary trajectories of both government and shipping companies spiral towards a unique evolutionary stable strategy, addressing the shortcomings of static penalty mechanisms. (2) Government supervision costs negatively impact the zero-carbon transition of shipping companies, while supervision intensity has a positive effect. Government subsidies positively affect transition strategies but have a minor impact. Increasing the penalty cap benefits the zero-carbon transition of companies. (3) There is a critical point for carbon trading prices corresponding to changes in zero-carbon transition strategies, providing a basis for companies to decide whether to buy or sell carbon emission trading rights. Additionally, government regulatory changes lag behind the changes in companies’ zero-carbon transition behaviors. The results provide significant insights for government strategy formulation and investment in zero-carbon transition under the carbon quota trading mechanism.
Do Economic Growth Targets Hinder Green Innovation? Evidence from Chinese Heavy-Polluting Enterprises
Authors: Gao Hong , Gao Peng
Published: December 2024

This article reports on a study examining 28 university engineering educators’ viewpoints on how to provide continuing education for professional engineers in a Danish university context. The Q methodology was adopted to collect and analyze data qualitatively and quantitatively. Three significantly different viewpoints were identified, prioritizing (1) a continuing engineering educa-tion (CEE) business model as an institutional priority, (2) organizational structure, and (3) pedagogy inspired by problem-based learning (PBL). The study also captured consensus on the importance of identifying the industry’s need for CEE organizations. The results reveal that CEE development needs to address diverse voices from different stakeholders, including leadership, academic faculty, and administrators; thus, suggestions from an organizational change perspective are proposed in four key aspects of CE organizations.
Downlink Non-Orthogonal Multiple Access Power Allocation Algorithm Based on Double Deep Q Network for Ensuring User’s Quality of Service
Authors: Lin Ying , Gong Xingbo , Xiong Yongwei , Li Haomin , Wang Xiangcheng
Published: December 2024

Non-orthogonal multiple access (NOMA) provides higher spectral efficiency and access to more users than orthogonal multiple access. However, the issue of resource allocation in NOMA is dynamic and produces a high computation burden when using traditional methods. In this paper, a symmetry-aware double deep Q network (DDQN) algorithm in deep reinforcement learning is employed to allocate power to users in NOMA while guaranteeing quality of service for the weakest users. The research process is divided into two parts. Firstly, users in the communication system are grouped using a method that synergistically considers gain difference and similarity, exploiting symmetrical properties within the user groups. Secondly, the DDQN algorithm is used to allocate power to multiple users in a NOMA system, which utilizes the inherent symmetry in the signal-to-interference noise ratio of each user as an objective function. By recognizing and leveraging these symmetrical patterns, the algorithm can dynamically adjust the power allocation to optimize system performance. Finally, the proposed algorithm is compared with conventional NOMA power allocation algorithms and shows significant improvements in system performance. The results of the convergence function show that the algorithm proposed in this paper can converge in approximately 1800 iterations, which effectively solves the problem of large arithmetic and complex processes existing in the traditional method.
Codes with Weighted Poset Metrics Based on the Lattice of Subgroups of Zm
Authors: Jitjankarn Phichet
Published: December 2024

By combining a lattice subgroup diagram of Zm with a weighted poset metric, we introduce a new weighted coordinates poset metric for codes over Zm, called the LS-poset metric. When I is an ideal in a poset, the concept of I-perfect codes with an LS-poset metric is investigated. We obtain a Singleton bound for codes with the LS-poset metric and define MDS codes. When the poset in the poset metric is a chain, we provide sufficient conditions for a code with the LS-poset metric to be r-perfect for some r∈N.