bluuebunny/crossref_metadata_2025 huggingface dataset:
Computational Study of the Plasma Actuator Flow Control for an Airfoil at Pre-Stall Angles of Attack
Authors: Ogawa Takuto , Asada Kengo , Sato Makoto , Tatsukawa Tomoaki , Fujii Kozo
Published: September 2022

Large-eddy simulations of the flows over an NACA0015 airfoil were conducted to investigate a flow control authority of a dielectric barrier discharge plasma actuator at pre-stall angles of attack. The Reynolds number was set to 63,000, and angles of attack were set to 4, 6, 8, and 10 degrees. The plasma actuator was installed at 5% chord length from the airfoil’s leading edge. Good flow control authority was confirmed in terms of lift-to-drag ratio increase and drag reduction. These improvements mainly result from the reduction of the pressure drug, which is due to the change in pressure distribution accompanying the movement and shrink of the laminar separation bubble on the airfoil surface. Additionally, although flow control using a burst drive with a nondimensional burst frequency of six improves the lift-to-drag ratio at all angles of attack, the phenomena leading to the improvement differ between near-stall angles (10 and 12 degrees) and the other lower angles. At near-stall angles, the turbulent transition is rapidly promoted by PA, and the flow is reattached. Whereas, at the lower angles, the transport of two-dimensional vortex structures, which maintain their structures up to downstream and suppress the turbulent transition, makes the flow reattachment.
Investigating Proactive Digital Forensics Leveraging Adversary Emulation
Authors: Machaka Valentine , Balan Titus
Published: September 2022

Traditional digital forensics techniques are becoming obsolete due to rapid technological change. Proactive digital forensic investigations (PDFI) solve the challenges of cloud computing forensics such as evidence identification, collection, preservation, and timelining from heterogeneous cumulative data. Cumulative data heterogeneity poses significant challenges to the sound collection of electronically stored information (ESI) or digital evidence across cloud endpoints and/or networked systems. In addition, the distribution of networked systems and/or cloud environments makes it impossible for forensics investigators to be present at several premises to perform the investigation. Hence, it is important to have PDFI in place to ensure continuous operation in the event of a cyberattack, because it does not require the presence of an investigator at the target location. In this study, researchers put the idea of proactive digital forensics to the test and concluded that it is an indispensable tool for networked systems and cloud computing environments in response to modern-day digital forensics challenges. This research was based on an experimental computer science and engineering approach using a virtualised environment simulating an information communication infrastructure. To generate evidence (digital artefacts), and validate the proof-of-concept, adversary emulation was used by adapting the MITRE ATT&CK framework. Research results have shown that PDFI improves digital forensics activities in terms of speed and accuracy, thereby providing credible and timely comprehensive digital evidence. Enhanced Incident detection capabilities enable an analyst to focus much more on forensic investigation functions and thus perform their tasks effectively. However, the legality of live and/or remote forensics is still of great concern in several jurisdictions, thereby affecting the credibility of digital artefacts obtained in this manner. Nevertheless, where possible, the law component should also be kept up to date with modern-day technologies to solve any inconveniences caused by the ever-growing technology demands.
Credibility Analysis on Twitter Considering Topic Detection
Authors: Hernandez-Mendoza Maria , Aguilera Ana , Dongo Irvin , Cornejo-Lupa Jose , Cardinale Yudith
Published: September 2022

Twitter is one of the most popular sources of information available on the internet. Thus, many studies have proposed tools and models to analyze the credibility of the information shared. The credibility analysis on Twitter is generally supported by measures that consider the text, the user, and the social impact of text and user. More recently, identifying the topic of tweets is becoming an interesting aspect for many applications that analyze Twitter as a source of information, for example, to detect trends, to filter or classify tweets, to identify fake news, or even to measure a tweet’s credibility. In most of these cases, the hashtags represent important elements to consider to identify the topics. In a previous work, we presented a credibility model based on text, user, and social credibility measures, and a framework called T-CREo, implemented as an extension of Google Chrome. In this paper, we propose an extension of our previous credibility model by integrating the detection of the topic in the tweet and calculating the topic credibility measure by considering hashtags. To do so, we evaluate and compare different topic detection algorithms, to finally integrate in our framework T-CREo, the one with better results. To evaluate the performance improvement of our extended credibility model and show the impact of hashtags, we performed experiments in the context of fake news detection using the PHEME dataset. Results demonstrate an improvement in our extended credibility model with respect to the original one, with up to 3.04% F1 score when applying our approach to the whole PHEME dataset and up to 9.60% F1 score when only considering tweets that contain hashtags from PHEME dataset, demonstrating the impact of hashtags in the topic detection process.
Community Battery Storage Systems Planning for Voltage Regulation in Low Voltage Distribution Systems
Authors: Alrashidi Musaed
Published: September 2022

The regulation of the grid voltage within operational limits becomes increasingly challenging as residential photovoltaic (PV) adoption rises. Therefore, this study proposes a method for the efficient planning of multiple community battery energy storage systems (BESS) in low voltage distribution systems embedded with high residential rooftop PV units. A bi-level optimization method based on a Neural Network Optimization Algorithm is developed to regulate the voltage in grid-connected solar PV. Since BESS characteristics are crucial for the reliable operation of the distribution networks, the objective of the bi-level optimization problem is to optimally place and operate BESS collectively at a distributed system level. The charging/discharging protocol of the batteries management system is obtained utilizing linear programming that minimizes the daily voltage signal. Simulations were carried out on a modified IEEE low voltage test feeder to examine the impact of PV integration and BESS installation on the voltage profile. Experimental results show the efficacy of the proposed method in enabling the utility to determine the optimal location, capacity, and number of BESS in the distribution system to keep the network voltage magnitude within acceptable bounds. In addition, results demonstrate that the network topology, load profiles, and amount of PV power highly influence the BESS characteristics.
Seismic Performance of a Y-Shaped Irregular Bridge Subjected to Strong and Multidirectional Ground Motions
Authors: Dong Zhengfang , Guo Qing , Yin Junhong , Tian Linjie
Published: September 2022

A 1/20 scale model of a Y-shaped irregular bridge was designed, and shaking-table tests were performed to simulate its failure mechanism and performance characteristics when subjected to a multidirectional strong earthquake. The results showed that the irregular bridge structure could accelerate in the horizontal direction when subjected to vertical excitation. For both unidirectional and multidirectional excitation, the acceleration response of the pier top was more significant in the transverse direction than in the longitudinal direction. For the variable-section and branching curved beams (i.e., ramp), the response to three-dimensional excitation was equivalent to the direct superposition of the responses to bidirectional excitation and single vertical excitation. With multidirectional excitation, the girder and ramp were more prone to structural collision. However, the likelihood of structural collision was not increased with multidirectional excitation than with bidirectional excitation. The displacement of the pier and beam was very large at the junction of the variable-section main beam and branching curved beam, so bearing failure and falling beams easily occurred. Multidirectional excitation generally increased the vertical acceleration response of the two piers and pier top at the irregular bridge branch, demonstrating the need to consider shock absorption and isolation in designing these locations.
Laminoplasty on Kyphotic Cervical Alignments Suggests Poor Surgical Outcomes: A Comparative Finite Element Analysis of Laminoplasty on Different Alignments
Authors: Nishida Norihiro , Mumtaz Muzammil , Tripathi Sudharshan , Kelkar Amey , Mendoza Justin , Kumaran Yogesh , Goel Vijay K.
Published: September 2022

Cervical laminoplasty is a useful for treatment for cervical myelopathy. However, this procedure has limitations for kyphotic cervical alignments. We used the finite element (FE) analysis and investigated the biomechanical changes in intact and laminoplasty models with lordosis, straight, and kyphosis cervical alignments. A three-dimensional FE model of the cervical spine (C2–C7) with ligaments was created from computer tomography. The model was modified with the following cobb angles (a) intact–lordotic model (intact–L; C2–C7 angle: −10°), (b) intact–straight model (intact–S; C2–C7 angle: 0°), and (c) intact–kyphotic model (intact–K; C2–C7 angle: 10°). The C3–C6 laminoplasty was conducted on the three intact models, represented by the laminoplasty–lordosis model (LM–L), laminoplasty–straight model (LM–S), and laminoplasty–kyphosis model (LM–K), respectively. Pure moment with compressive follower load of 100 N to represent the weight of the head/cranium and cervical muscle stabilization was applied to these models and the range of motion (ROM), annular stress, nucleus stress and facet forces were analyzed. ROM of intact–K and LM–K increased when compared to the other models. The LM–K had the highest mobility with 324% increase in ROM observed under extension, compared to LM–L. In addition, the annular stresses and nucleus stresses in intact–K and LM–K were higher compared to the other models. The maximum increase in annular stresses was about 309% in LM–K compared to the LM–L, observed at the C3–C4 segment. However, the facet contact forces were lower in the intact–K and LM–K, compared to the other models. Cases with cervical kyphosis alignment are at a disadvantage compared to cases with lordosis or straight alignment and should be treated with caution.
The Design Value for Recycling End-of-Life Photovoltaic Panels
Authors: Calì Michele , Hajji Bekkay , Nitto Gioele , Acri Alberto
Published: September 2022

The production of electric energy has been increasingly deriving from renewable sources, and it is projected that this trend will continue over the next years. Among these sources, the use of solar energy is supposed to be considered the main future solution to global climate change and fossil fuel emissions. Since current photovoltaic (PV) panels are estimated to have an average life of 25–30 years, their disposal is very important for the recovery of materials already used and for introducing them again into other processing cycles. Innovative solutions are therefore needed to minimize the emissions of pollutants derived from the recycling of photovoltaic panels that no longer work. In this research, an analysis of data related to durability, recyclability rates, different possible design layouts and materials used in the design and manufacture of PV panels was conducted. Through a Design for Recycling (DfR) and a Design for Durability (DfD), the authors identified the optimal materials, the best geometries and geometric proportions as well as the most convenient geometric and dimensional tolerances in the couplings between the layers and the components that comprise the panel to attain the most current, efficient and effective solutions for recycling end-of-life (EoL) PV panels and for longer durability.
Examination of Nesting Behavior of Laying Hens of Different Genotypes Housed in Indoor Alternative Pens Using a Video System
Authors: Farkas Tamás Péter , Szász Sándor , Orbán Attila , Mezőszentgyörgyi Dávid , Pető Lilla , Sütő Zoltán
Published: September 2022

The aim of the research was to examine how the nest selection preference of laying hens with different genotypes differed, the proportion of eggs laid in the litter, eggs laid in the upper and bottom nests, and the number and duration of nest visits. The experiment was conducted with laying hen genotypes provided by Bábolna TETRA Ltd. (Babolna, Hungary) (Commercial hybrid (C); pure-line maternal (Maternal); pure-line paternal offspring group (Paternal)). N = 318; n = 106 hen/genotype; and 53 hens/pen. We placed 53 19-week-old, non-beak-trimmed hens in each of the six 5.52 m2 alternative pens. We provided 14 nests for the hens at two levels per pen (3.8 hens/nest). We recorded the number of eggs laid in the nests on the bottom and upper levels, as well as within the litter. Infrared cameras were installed above the pens, and we conducted recordings on a test day at the beginning of the third production month. In our results, we found a significant difference in the proportion of litter eggs overall during the 12 months of production (C. hybrid: 30.7%; Paternal: 41.1%; Maternal: 10.2%). A significant difference was found between all genotypes in the proportions of eggs laid at the bottom (B) and upper (U) level during the 12 months of production (C. hybrid: B: 72.2%, U: 27.8%; Paternal: B: 88.0%, U: 12.0%; Maternal: B: 71.4%, U: 28.6%). The evaluation of the video recordings revealed that the C. hybrid and Paternal genotypes visited the bottom nests in 97.2% and 96.0% of the cases, respectively, and the Maternal genotype individuals in a significantly lower proportion, 72.5% of the cases; the Paternal genotype spent significantly more time (13.4 min) on average in the bottom nests compared with the C. hybrid (7.9 min) and the Maternal genotypes (8.6 min). Our conclusion is that it is not enough to ensure the desired ratio of egg nests in egg production, as laying hens may not use nests in certain positions at all. This generates a relative shortage of egg nests and can increase the ratio of eggs laid in the litter, which in turn involves human health risks.
A Lightweight Residual Model for Corrosion Segmentation with Local Contextual Information
Authors: Huang Jingxu , Liu Qiong , Xiang Lang , Li Guangrui , Zhang Yiqing , Chen Wenbai
Published: September 2022

Metal corrosion in high-risk areas, such as high-altitude cables and chemical factories, is very complex and inaccessible to people, which can be a hazard and compromise people’s safety. Embedding deep learning models into edge computing devices is urgently needed to conduct corrosion inspections. However, the parameters of current state-of-the-art models are too large to meet the computation and storage requirements of mobile devices, while lightweight models perform poorly in complex corrosion environments. To address these issues, a lightweight residual deep-learning model based on an encoder–decoder structure is proposed in this paper. We designed small and large kernels to extract local detailed information and capture distant dependencies at all stages of the encoder. A sequential operation consisting of a channel split, depthwise separable convolution, and channel shuffling were implemented to reduce the size of the model. We proposed a simple, efficient decoder structure by fusing multi-scale features to augment feature representation. In extensive experiments, our proposed model, with only 2.41 MB of parameters, demonstrated superior performance over state-of-the-art segmentation methods: 75.64% mean intersection over union (IoU), 86.07% mean pixel accuracy and a 0.838 F1-score. Moreover, a larger version was designed by increasing the number of output channels, and model accuracy improved further: 79.06% mean IoU, 88.07% mean pixel accuracy, and 0.891 F1-score. The size of the model remained competitive at 8.25 MB. Comparison work with other networks and visualized results were used for validation and to determine the accuracy of metal corrosion surface segmentation with limited resources.
Structural, Magnetic, and Magnetocaloric Studies of Ball-Milled Fe100−xTx (T = Ni and Mn) Alloy
Authors: Sharma Mohit K. , Kumar Akshay , Kumari Kavita , Park Su-jeong , Yadav Naveen , Huh Seok-Hwan , Koo Bon-Heun
Published: September 2022

Iron-transition metal-based binary and ternary alloys have attracted great attention due to their relevant mechanical, electrical, and magnetic properties. In this paper, we systematically investigate the structural, magnetic, and magnetocaloric behavior of as-milled Fe65T35 (T = Ni and Mn) alloy. The polycrystalline alloys were produced by the planetary ball milling, using a powder-to-ball ratio of 1:3. A structural study reveals that both Fe65Ni35 and Fe65Mn35 compounds have stabilized in α and γ mixed phase within the cubic crystal structure. The alloyed compounds are further characterized by high-resolution field emission scanning electron microscopy (HR-FESEM), which confirms the mixing of both metals in the alloying process. Temperature-dependent magnetic studies do not show any blocking in zero-field-cooled and field-cooled results; however, the field-dependent magnetization study demonstrates the ferromagnetic nature with small hysteresis in both compounds. Both compounds show a significant magnetocaloric effect over a wide temperature range around room temperature. Fe65Ni35 exhibit a slightly higher value in comparison to Fe65Mn35. In both the alloys, magnetic entropy change follows the power law behavior against the external magnetic field, and the value of exponent ‘m’ explains the presence of magnetic correlation. Our investigation in this study communicates that the phase control or coexistence of both phases may be efficacious in obtaining the desirable characteristic of magnetic and magnetocaloric demeanors in such a binary Fe-T alloy.
Enhanced Performance of Concrete Dispersedly Reinforced with Sisal Fibers
Authors: Beskopylny Alexey N. , Stel’makh Sergey A. , Shcherban Evgenii M. , Mailyan Levon R. , Meskhi Besarion , Shilov Alexandr A. , Beskopylny Nikita , Chernil’nik Andrei
Published: September 2022

The fibers used in concrete are mainly materials that require additional production, which negatively affects their cost and environmental friendliness. Therefore, the issue of the effectiveness of the use of natural fibers, the extraction of which does not require mechanized production, becomes relevant. One of these materials is sisal fiber. The main purpose of this work was to study the effect of adding sisal fibers on the structure and properties of environmentally friendly concretes with improved characteristics. The tests were carried out in strict accordance with technological recommendations and normative and technical documents. Laboratory samples were made in the form of cubes and prisms of concrete with a compressive strength of 48 MPa and sisal fiber content of 0.25%, 0.5%, 0.75%, 1.0%, 1.25% and 1.5%. The tests were carried out at a concrete age of 15 days. The compressive strength and tensile strength of concrete samples were studied using the method of optical microscopy. The optimal content of fiber reinforcement with sisal fiber was determined as equal to 1%. The increases in the strength characteristics of the obtained fiber-reinforced concrete samples at the optimal dosage of sisal fiber in an amount of 1% by weight of cement were 22% for compressive strength, 27% for axial compressive strength, 33% for tensile strength in bending and 29% for axial strength stretching. The increases in deformation characteristics were 25% for strains in axial compression, 42% for strains in axial tension and 15% for the elastic modulus.
Theoretical Analysis on the Effectiveness of Pipe Roofs in Shallow Tunnels
Authors: Li Yuxiang , Wang Wen , Yan Songhong , Du Jiaxuan
Published: September 2022

When a pipe roof is used as a pre-support for the surrounding rock in a shallowly buried tunnel, accurate prediction of the support effectiveness of the pipe roof is important in order to ensure the rationality of the pipe roof structure design. Based on analysis of pipe roof pre-support effects, considering the construction time of pipe roof structures and the interaction mechanisms between the steel pipes of the pipe roof and the surrounding rock, we establish a calculation model of the surrounding rock pressure acting on each steel pipe of the pipe roof on the semi-circular pre-support boundary. Through comparison and analysis with the measured results, we demonstrate that the calculation model for surrounding rock pressure and the calculation model for stress and deformation of the pipe roof are reasonable. According to the deformation coordination conditions between the steel pipe of the pipe roof and the surrounding rock on the pre-support boundary and alongside the Peck formula, we establish a theoretical analysis method for pipe roof pre-support effectiveness based on the indexes of the ground loss rate, settlement trough width, and maximum ground surface settlement, thereby realizing a quantitative evaluation of pipe-roof pre-support effectiveness. At the same time, the effects of steel pipe diameter, circumferential spacing, and excavation footage length on the pre-support effectiveness of the pipe roof are analyzed. The conclusions can be used as a basis for the design and optimization of pipe roofs and as a guide for the application of pipe roofs.
Mechanical Analysis of Bolt-Lining Combined Support in Deeply Buried Circular Tunnel
Authors: Liu Yijie , Lu Aizhong , Cai Hui
Published: September 2022

The proposal of the NATM has changed people’s understanding of the support principle. Therefore, how to improve the self-supporting capacity of surrounding rock has become an important issue in support research. Bolts and lining are widely used together in various support projects because their bearing and reinforcement effects are in line with the concept of the NATM. This paper puts forward a model to analyze the mechanical behavior of a deeply buried circular tunnel jointly supported by lining and point-anchored rock bolts. Rock mass, lining, and bolts maintain an elastic state and are in full contact with each other. In addition, point-anchored rock bolts are replaced by pairs of concentrated forces of equal magnitude that act in opposite directions. By using the complex function method, the linear equations for calculating the axial force of the bolts and the relevant analytical function coefficients can be established, based on the stress condition of the inner boundary of the lining, the continuity conditions at the interface between the lining and the surrounding rock, and the compatibility condition of the displacement between the bolts and the surrounding rock. Then, using the analytical functions, the stress and displacement of any point in the lining and surrounding rock can be calculated. The results were compared with the numerical solutions. Moreover, the effects of the bolts and the Young’s modulus of the lining on the whole support system are discussed.
Short-Time Traffic Forecasting in Tourist Service Areas Based on a CNN and GRU Neural Network
Authors: Yang Yan-Qun , Lin Jie , Zheng Yu-Bin
Published: September 2022

The continuous development of highway construction projects has prompted the function of service areas to be improved day by day. A traditional service area gradually transforms from a single traffic service mode to a complex traffic service mode. The continuous enrichment and perfection of the service area’s function makes the surrounding highway network more attractive, which leads to a sudden increase in highway traffic volume in a short period of time. In order to better improve the service level of a tourist service area by predicting the short-term traffic volume of the toll station around the tourist service area, this paper proposes a model combining a convolutional neural network and a gated recurrent unit (CNN plus GRU) to solve the problem of short-term traffic volume prediction. The data from 17 toll stations of the Yu’an Expressway in Guizhou Province were selected for the experiment to test the prediction effect of the CNN plus GRU-based model. The experimental results show that the prediction accuracy, the MAE and RMSE, are 1.8101 and 2.7021, respectively, for the toll stations with lower traffic volumes, and 3.820 and 5.172, respectively, for the toll stations with higher traffic volumes. Compared with a single model, the model’s prediction accuracy is improved, to different degrees. Therefore, the use of a convolutional neural network operation is better when the total traffic volume is low, considering the algorithm’s time and error. When using the combined convolutional neural network and gated recurrent unit model and when the total traffic volume is high, the algorithm error is significantly reduced and the prediction results are better.
Physical Activity Programmes in the Treatment of Addictions: A Systematic Review
Authors: Castillo-Viera Estefanía , Gago-Valiente Francisco-Javier , Giménez-Fuentes-Guerra Francisco-Javier , Abad-Robles Manuel-Tomás , Moreno-Sánchez Emilia
Published: September 2022

Background: The scientific literature was reviewed with the aim of determining the current state of the research on relationships between physical activity programmes and addiction treatment. Methods: The search was carried out in the WOS, Scopus and PubMed databases, restricting the publication language to English and Spanish, and it was limited to studies conducted in the last 5 years, i.e., between 1 January 2016 and 31 November 2021, selecting only open-access articles with physical activity programmes for the treatment of addictions to harmful substances. Results: Of the 38 initial articles selected, a total of 10 articles were ultimately included, as they met the established eligibility criteria after performing a more exhaustive analysis. The results show a positive relationship between physical activity and adherence to addiction cessation treatment. Conclusions: Physical activity has been incorporated into coadjuvant treatments in combination with other pharmacological or behavioural treatments. These results strengthen the importance of promoting physical activity in rehabilitation and substance-withdrawal treatments. Complementarily, physical activity programmes improve other health variables that influence the quality of life, such as sleep quality and mood, and reduce the risk of social exclusion. Physical activity also directly reduces a sedentary lifestyle, which is responsible for more than 40 diseases and chronic disorders.
Pursuit–Evasion Problem of Unmanned Surface Vehicles in a Complex Marine Environment
Authors: Sun Zhiyuan , Sun Huawei , Li Ping , Li Xiaowen , Du Lei
Published: September 2022

In order to solve the interception problem of escaping targets under environmental interference and inaccurate target perception, this paper introduces the guidance interception algorithm and introduces a Kalman filter to predict the trajectory of escaping targets. In order to make a USV pursuit under a disturbance in a time-varying real marine environment, a disturbance observer is proposed to estimate the external disturbance and model uncertainty. The simulation of pursuit–evasion results shows that the interception algorithm designed enables the pursuer to intercept the escaping target in a time-varying, disturbed marine environment. Both the simulation and experimental results are provided to validate the effectiveness of the method.
Upgraded Combined Inject-and-Transfer System for Serial Femtosecond Crystallography
Authors: Lee Keondo , Lee Donghyeon , Park Jaehyun , Lee Jong-Lam , Chung Wan Kyun , Cho Yunje , Nam Ki Hyun
Published: September 2022

Serial femtosecond crystallography (SFX) using an X-ray free-electron laser (XFEL) can be applied to determine the room-temperature structure of target molecules while minimizing radiation damage and visualizing molecular dynamics. In SFX, a sample delivery system is required to deliver microcrystals to the XFEL beam path in a serial manner. We recently developed a sample delivery method, the combined inject-and-transfer system (BITS), which is a hybrid method based on the injector and fixed-target scanning approach. In this study, we introduced recently upgraded hardware to move the injection needle in the direction of the XYZ-axis and a graphic user interface for user motion control. Furthermore, we report that the viscous solution containing 10% (w/v) PEG 3350 or PEG 6000 that is widely used for protein crystallization can be stably deposited on polyimide film with a hydrophobic surface without any special treatment. Moreover, the development of an inject-and-diffuse method for time-resolved studies with liquid applications in the BITS and its preliminary results are reported. This study provides up-to-date instrument information to SFX users using BITS and provides insights to instrument developers for SFX.
Special Issue on Trends in Sub-Microsecond X-ray Science with Coherent Beams
Authors: Lee Sooheyong , Landahl Eric C. , Roseker Wojciech
Published: September 2022

Large increases in synchrotron brightness have brought notable breakthroughs in measurement techniques that exploit transverse coherence, such as X-ray photon correlation spectroscopy (XPCS), coherent diffraction imaging (CDI), diffraction microscopy, and ptychography [...]
A Novel Efficient Method for Simulating Non-Stationary Random Processes Combining Generalized Harmonic Wavelet and Stochastic Harmonic Function
Authors: Wang Ding , Yu Feixiang , Xu Shan
Published: September 2022

Integrating the general expression of the generalized harmonic wavelet (GHW)-based spectral representation method (SRM) and the idea of stochastic harmonic function (SHF), a novel stochastic generalized harmonic wavelet (SGHW) method for fully nonstationary stochastic processes, is established. The advantages of the proposed method are (1) a stochastic process with accurate probability information can be obtained by retaining fewer components. A smaller number of components greatly reduces the number of random variables. Fewer random variables also reduce the difficulty of random process analysis. The superior fitting effect between evolutionary power spectral density (EPSD) obtained from the samples using the SGHW method and the EPSD model proves the validity and effectiveness of the SGHW method. (2) The proposed method contains more accurate probability information and has a higher computational efficiency. The comparisons of relative errors and computational time between the SGHW method and the SRM demonstrate the accuracy and efficiency of the proposed method.
Estimation and Reliability Research of Post-Earthquake Traffic Travel Time Distribution Based on Floating Car Data
Authors: Li Yongyi , Wang Shiqi , Zhang Xiaorui , Lv Mengxing
Published: September 2022

To carry out the estimation and reliability research of post-earthquake traffic travel time, which has the great influence for efficient allocation of relief materials. By analyzing the relationship among floating vehicle trajectory, target path and road network path, the intermediate parameters of converting floating vehicle trajectory data into target path travel time were defined and improved. In addition, the road damage identification method relying on lane detection is applied for evaluating the damage of road after the earthquake through the image information. Then, Bayesian average adaptive kernel density estimation method was used to estimate the distribution of post-earthquake road travel time, and a new formula for calculating the reliability of road travel time after earthquake was proposed. According to the example simulation and analysis, the proposed post-earthquake road travel time distribution estimation and its reliability are verified. The results show that when the threshold value is determined, the travel time of the path before the earthquake is the most dependable, and with the increase in the earthquake damage index, the travel time of this road section becomes increasingly unreliable. However, after the earthquake, the peak probability density of road travel time distribution weakens, and the overall probability shifts to the direction of long time.
Vastus Lateralis and Vastus Intermedius as Predictors of Quadriceps Femoris Muscle Hypertrophy after Strength Training
Authors: Spiliopoulou Polyxeni , Methenitis Spyridon , Zaras Nikolaos , Stasinaki Angeliki-Nikoletta , Krekoukia Maria , Tsitkanou Stavroula , Terzis Gerasimos
Published: September 2022

The aim of the present study was to investigate which of the four musle heads of the quadriceps femoris is the best surrogate of quadriceps hypertrophy, following resistance training, evaluated by ultrasonography. Forty three physical education students (age: 22.1 ± 3.1 years, height: 175.2 ± 9.3 cm, mass: 75.3 ± 8.0 kg, BMI: 22.8 ± 2.8 kg·m−2) participated in the study. Participants followed an 8-week resistance training program in order to enhance quandriceps muscle hypertrophy. Before and after the training period muscle ultrasonography was used to evaluate: total quandriceps (T), vastus lateralis (VL), vastus intermidius (VI), vastus medialis (VM) and rectus femoris (RF) cross sectional area (CSA). Total quadriceps’ as well as VL, VI and VM, CSAs were significantly increased after training (changes ranged between 10.9 ± 9.9% and 18.6 ± 10.8%; p < 0.05). No significant changes were found for RF CSA after training (p > 0.05). Agreement analyses revealed high values for VL and VI (e.g., ICC = 0.879–0.915; p = 0.000), and low values for VM and RF (e.g., ICC = 0.132–0.526; p = 0.000). These results suggest that training-induced changes in muscle hypertrophy in VL and VI measured via muscle ultrasonography may be significantly predict the whole quadriceps hypertrophy in response to lower body resistance training. Consequently, VL and VI may considered as valid surrogates of whole quadriceps muscle hypertrophy.
A Data-Driven Approach for University Public Opinion Analysis and Its Applications
Authors: He Miao , Ma Chunyan , Wang Rui
Published: September 2022

In the era of mobile Internet, college students increasingly tend to express their opinions and views through online social media; furthermore, social media influence the value judgments of college students. Therefore, it is vital to understand and analyze university online public opinion over time. In this paper, we propose a data-driven architecture for analysis of university online public opinion. Weibo, WeChat, Douyin, Zhihu and Toutiao apps are selected as sources for collection of public opinion data. Crawler technology is utilized to automatically obtain user data about target topics to form a database. To avoid the drawbacks of traditional methods, such as sentiment lexicon and machine learning, which rely on a priori knowledge and complex handcrafted features, the Word2Vec tool is used to perform word embedding, the LSTM-CFR model is proposed to realize Chinese word segmentation and a convolutional neural network (CNN) is built to automatically extract implicit features in word vectors, ultimately establishing the nonlinear relationships between implicit features and the sentiment tendency of university public opinion. The experimental results show that the proposed model is more accurate than SVM, RF, NBC and GMM methods, providing valuable information with respect to public opinion management.
Experimental Study on the Influence of Moisture and Clay Content on Stress Wave Attenuation Characteristics of Filled Joints
Authors: Li Sheng , Xiong Ziming , Fan Pengxian , Xie Kaidi
Published: September 2022

Artificial filled joints made of sand–clay mixtures with different clay weight fractions and saturations have different wave attenuation capacities. In this paper, the high amplitude impact test of sand–clay mixtures was carried out by using split Hopkinson pressure bar (SHPB) equipment. The results showed that with the increase of clay weight fraction, the particle crushing decreased continuously, while the wave attenuation coefficient decreased first and then increased. When the weight fraction of clay was 50%, the wave attenuation coefficient reached the minimum among the tested working conditions, and the ratio of transmitted energy to incident energy reached the maximum. With the increase of saturation, the particle crushing decreased first and then increased, while the wave attenuation coefficient increased first and then decreased. When the saturation was 25%, the wave attenuation coefficient reached the maximum, and the proportion of transmitted energy to incident energy reached the minimum. Because of the lubrication of water reduced the friction between particle, the specimen more prone to deformation and particle crushing reduced. As the saturation increased, this effect gradually decreased. In the case of the wave absorbing layer of protective works, special attention should be paid to the adverse effects caused by groundwater.
An Air Pollutants Prediction Method Integrating Numerical Models and Artificial Intelligence Models Targeting the Area around Busan Port in Korea
Authors: Hong Hyunsu , Choi IlHwan , Jeon Hyungjin , Kim Yumi , Lee Jae-Bum , Park Cheong Hee , Kim Hyeon Soo
Published: September 2022

Exposure to air pollutants, such as PM2.5 and ozone, has a serious adverse effect on health, with more than 4 million deaths, including early deaths. Air pollution in ports is caused by exhaust gases from various elements, including ships, and to reduce this, the International Maritime Organization (IMO) is also making efforts to reduce air pollution by regulating the sulfur content of fuel used by ships. Nevertheless, there is a lack of measures to identify and minimize the effects of air pollution. The Community Multiscale Air Quality (CMAQ) model is the most used to understand the effects of air pollution. In this paper, we propose a hybrid model combining the CMAQ model and RNN-LSTM, an artificial neural network model. Since the RNN-LSTM model has very good predictive performance, combining these two models can improve the spatial distribution prediction performance of a large area at a relatively low cost. In fact, as a result of prediction using the hybrid model, it was found that IOA improved by 0.235~0.317 and RMSE decreased by 4.82~8.50 μg/m3 compared to the case of using only CMAQ. This means that when PM2.5 is predicted using the hybrid model, the accuracy of the spatial distribution of PM2.5 can be improved. In the future, if real-time prediction is performed using the hybrid model, the accuracy of the calculation of exposure to air pollutants can be increased, which can help evaluate the impact on health. Ultimately, it is expected to help reduce the damage caused by air pollution through accurate predictions of air pollution.
Future Projections of Extreme Precipitation Climate Indices over South America Based on CORDEX-CORE Multimodel Ensemble
Authors: Reboita Michelle Simões , da Rocha Rosmeri Porfírio , Souza Christie André de , Baldoni Thales Chile , Silva Pedro Lucas Lopes da Silveira , Ferreira Glauber Willian S.
Published: September 2022

Climate change is undeniable, and its effects, like droughts and intense precipitation, evidence this reality. However, many questions remain unanswered, such as climate extremes’ future frequency and intensity. International collaboration projects such as the Coordinated Regional Climate Downscaling Experiment (CORDEX)-Coordinated Output for Regional Evaluations (CORE) have emerged to address these questions, creating protocols to facilitate the intercomparison among simulations obtained by different regional climate models (RCMs). Given this context, this study aims to describe the projected changes in the extreme precipitation events over the South America domain by using a set of projections of three RCMs (Eta, RegCM, and REMO) under the CORDEX-CORE framework (except Eta). These models were nested in different global climate models (GCMs) from Coupled Model Intercomparison Project phase 5 (CMIP5) under the RCP8.5 scenario and integrated with a grid space of 25 km. In addition, six climate indices (PRCPTOT, SDII, R95p, P95, CDD, and CWD) were computed by season for the historical period (1995–2014) and four future time-slices (2020–2039, 2040–2059, 2060–2079, and 2080–2099). For brevity, this study focuses on the austral summer. RCMs are generally capable of representing the spatial pattern of climate indices but with differences in intensity. The ensemble with all RCMs shows a slightly better spatial correlation with the reference data than the ensemble of each RCM. The signal of the projections is similar between RegCM and REMO and, in general, opposite to Eta (mainly in the South Atlantic Convergence Zone region). Of the six climate indices analyzed, the ensemble performed with the three RCMs projects statistically significant negative (positive) trends for four indices in the Amazon (La Plata Basin), indicating a signal of dry (wet) conditions increasing towards the end of the century. Furthermore, both regions have significant positive (negative) trends of consecutive dry (wet) days. The region with higher uncertainties lies over southeastern Brazil, where Eta projects a dry climate and RegCM and REMO, a wet one.
Comparison of Urban Canopy Schemes and Surface Layer Schemes in the Simulation of a Heatwave in the Xiongan New Area
Authors: Xu Yiguo , Gao Wanquan , Fan Junhong , Zhao Zengbao , Zhang Hui , Ma Hongqing , Wang Zhichao , Li Yan , Yu Lei
Published: September 2022

Due to rapid growth and expansion, Xiongan New Area is at risk for heatwaves in the present and future induced by the urban heat island effect. Based on eight combined schemes, including two common WRF surface layer schemes (MM5 and Eta) and urban canopy schemes (SLAB, UCM, BEP and BEP + BEM), simulation performance for 2-m temperature, 2-m relative humidity and 10-m wind during a heatwave in July 2019 was compared and analyzed. The simulation performance is ranked from best to worst: 2-m temperature, 2-m relative humidity, 10-m wind direction and 10-m wind speed. MM5 simulate 2-m temperature and 10-m wind speed better than Eta, but 2-m relative humidity worse. MM5 coupling BEP + BEM provides the highest simulation performance for 2-m air temperature, 10-m wind direction and 10-m wind speed but the worst for 2-m relative humidity. MM5 and Eta produce nearly opposite results for wind direction and wind speed. Due to the Anxin station close to Baiyang Lake, lake-land breeze affects the simulation findings, worsening the correlation between simulated 10-m wind and observation.
Anthropogenic Influence on the Antarctic Mesospheric Cooling Observed during the Southern Hemisphere Minor Sudden Stratospheric Warming
Authors: Eswaraiah Sunkara , Seo Kyong-Hwan , Kumar Kondapalli Niranjan , Ratnam Madineni Venkat , Koval Andrey V. , Jeong Jin-Yun , Mengist Chalachew Kindie , Lee Young-Sook , Greer Katelynn , Hwang Jun-Young , Lee Wonseok , Pramitha Maniyattu , Venkata Chalapathi Gasthi , Venkatarami Reddy Mannem , Kim Yong Ha
Published: September 2022

Processes behind Sudden Stratospheric Warming (SSW), which occurs more frequently in the northern hemispheric polar latitudes and its influence from the stratosphere to the upper atmosphere are well documented. However, physical processes associated with SSW, although it ensues rarely in the southern hemisphere (SH), have a strong influence on the background atmosphere from the stratosphere to the mesosphere and are poorly understood. Using a ground-based meteor radar, satellite-borne Microwave-Limb sounder, and Modern-Era Retrospective Analysis for Research and Applications observations, we identified cooling of Antarctic mesopause by 26 K in response to a 66 K warming in the polar stratosphere during the 2019 minor SSW in the SH. The observed cooling is attributed to the interplay between planetary waves, CO2 infrared cooling, and O3 depletion, rather than adiabatic cooling due to gravity waves alone during SSW. It is proposed that anthropogenic and other sources generating chemical tracers in the lower atmosphere have caused mesospheric cooling and could be transported from the lower atmosphere both vertically and meridionally through residual mean meridional circulation from the tropics. Therefore, our study for the first time demonstrates the effect of lower atmosphere chemistry on the polar mesosphere thermal structure during the 2019 SSW.
Comparative Analysis of the Observation Bias and Error Characteristics of AGRI and AHI Data for Land Areas in East Asia
Authors: Wang Shuqing , Qin Zhengkun , Tang Fei
Published: September 2022

Observation bias and error characteristics are the preconditions for the effective assimilation of observation data. In this paper, the bias and error characteristics of the AHI (Advanced Himawari Imager (AHI) and AGRI (Multi-Channel Advanced Geostationary Orbit Radiation Imager (AGRI) data are compared and analyzed, with an emphasis on the observations obtained from land areas. The results show that the observation errors of the two instruments for the ocean area have a good channel consistency over ocean areas, which are all with errors of about 0.6 K; however, the bias and error are significantly affected by the land-surface types and terrain heights over land. For most of the AHI channels, the bias in urban-area bias is smaller than that of those of other surface types, while that of the AGRI data exhibits just the opposite trend, with obviously larger biases in urban areas. However, the observation errors of these two instruments in urban areas are significantly smaller than those of other surface types. The biases of the two instruments do not extensively change much with the terrain height, only slightly decreasing when the height is above 1000 m; however, the observation errors increase obviously with the increase of terrain heights. The difference between the two instruments is that the observation error of the AHI data tends to be stable and stabilizes above 1000 m, while that of the AGRI data is relatively stable below 500 m. The observation errors of the CO2-sensitive channels of the two instruments over the land areas are obviously smaller than those of other near-surface channels, which may indicate that the data obtained in these two CO2 channels have good application prospects for assimilation over land.