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Appl. Sci., Volume 11, Issue 18 (September-2 2021) – 515 articles

Cover Story (view full-size image): Swarm Intelligence (SI) algorithms imitate the collective behavior of various swarms or groups in nature. In this work, three representative examples of SI algorithms were selected, namely, the Grey Wolf Optimizer (GWO), the Whale Optimization Algorithm (WOA), and the Salp Swarm Algorithm (SSA). These SI algorithms were applied to the synthesis of linear antenna arrays to optimize the peak sidelobe level (pSLL). Numerical tests showed that the WOA outperforms the GWO and SSA algorithms. Finally, the WOA was exploited to solve the synthesis problem of a dual-band aperture-coupled E-shaped antenna operating in 5G frequency bands. View this paper
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Article
Static Balancing Ability and Lower Body Kinematics Examination of Hungarian Folk Dancers: A Pilot Study Investigating the “Kalocsai Mars” Dance Sequence
Appl. Sci. 2021, 11(18), 8789; https://0-doi-org.brum.beds.ac.uk/10.3390/app11188789 - 21 Sep 2021
Viewed by 348
Abstract
Folk dance is a collection of traditional dances that requires years of practicing to perform correctly. The aim of the present study was to develop a complex biomechanical measurement procedure that investigated Hungarian folk dancers’ balancing ability and lower body kinematics through a [...] Read more.
Folk dance is a collection of traditional dances that requires years of practicing to perform correctly. The aim of the present study was to develop a complex biomechanical measurement procedure that investigated Hungarian folk dancers’ balancing ability and lower body kinematics through a dance movement called “Kalocsai mars”. Therefore, 11 dancers’ motion (5 female and 6 male; age: 20.5 ± 2.5 years; height: 173.82 ± 7.82 cm; weight: 64.77 ± 8.67 kg) was recorded with an optical-based motion capture system and force platforms simultaneously. Before and after the dancing session, static balancing tests were performed, examining bipedal stance with eyes opened and closed conditions. The ANOVA results showed that the values of the range of motions of the knee joint flexion-extension angles and hip flexion averaged for sessions increased significantly (p=0.044, p=0.003, p=0.005) during the dancing sessions. The deviation in the joint angle was greater in the nondominant legs, suggesting that the nondominant side requires more attention to execute the dance steps correctly. The results of the balance tests showed that the oscillation in the posterior direction increased significantly after dancing (p=0.023). In comparison, the visual feedback had no significant effect on the dancers’ balancing ability. Full article
(This article belongs to the Special Issue Applied Biomechanics and Motion Analysis)
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Article
Optimization of Electricity Generation Technologies to Reduce Carbon Dioxide Emissions in Egypt
Appl. Sci. 2021, 11(18), 8788; https://0-doi-org.brum.beds.ac.uk/10.3390/app11188788 - 21 Sep 2021
Viewed by 521
Abstract
In February 2016, the Egyptian government introduced Egyptian Vision 2030. An important pillar of this vision is energy. Egyptian Vision 2030 presented renewable energy as the best solution to reduce the emission of greenhouse gases (GHGs) in the energy sector. Egypt’s electricity comes [...] Read more.
In February 2016, the Egyptian government introduced Egyptian Vision 2030. An important pillar of this vision is energy. Egyptian Vision 2030 presented renewable energy as the best solution to reduce the emission of greenhouse gases (GHGs) in the energy sector. Egypt’s electricity comes from various power plants; conventional thermal plants generate over 90% in which gas-fired generation accounts for 75% of the total output. Following the increase in natural gas (NG) projects in Egypt, NG is the dominant electricity source. Based on the pillars of the sustainable development strategy of Egypt, the county can increase dependence on renewable energies, and reduce CO2 emissions and bound electricity production from natural gas. We aim to determine future energy generation strategies from various power plant technologies depending on these three principles. To make the picture more clear and complete, we compared the environmental impacts and external costs of fossil, hydro, and nuclear power plants in Egypt. We used two computer codes: the model for energy supply strategy alternatives and their general environmental impacts (MESSAGE) and the simplified approach for estimating environmental impacts of electricity generation (SIMPACTS). The MESSAGE code modeled the energy-supply systems to determine the best energy-supply technology to meet future energy demands. SIMPACTS estimated the environmental impact and damage costs associated with electricity generation. The results indicated that nuclear power plants and gas power plants are long-term electricity supply sources. Nuclear power plants entail low total external-damage costs, in addition to low environmental impact during normal operation. We conclude that nuclear power plants are the best alternative long-term electricity-generation choice for Egypt to meet future electricity demands. Full article
(This article belongs to the Section Energy)
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Review
Facing Phototrophic Microorganisms That Colonize Artistic Fountains and Other Wet Stone Surfaces: Identification Keys
Appl. Sci. 2021, 11(18), 8787; https://0-doi-org.brum.beds.ac.uk/10.3390/app11188787 - 21 Sep 2021
Viewed by 394
Abstract
All fountains are inhabited by phototrophic microorganisms, especially if they are functional and located outdoors. This fact, along with the regular presence of water and the intrinsic bioreceptivity of stone material, easily favors the biological development. Many of these organisms are responsible for [...] Read more.
All fountains are inhabited by phototrophic microorganisms, especially if they are functional and located outdoors. This fact, along with the regular presence of water and the intrinsic bioreceptivity of stone material, easily favors the biological development. Many of these organisms are responsible for the biodeterioration phenomena and recognizing them could help to define the best strategies for the conservation and maintenance of monumental fountains. The presence of biological growth involves different activities for the conservation of artistic fountains. This paper is a review of the phototrophic biodiversity reported in 46 fountains and gives a whole vision on coping with biodeteriogens of fountains, being an elementary guide for professionals in the field of stone conservation. It is focused on recognizing the main phototrophs by using simplified dichotomous keys for cyanobacteria, green algae and diatoms. Some basic issues related to the handling of the samples and with the control of these types of microalgae are also briefly described, in order to assist interested professionals when dealing with the biodiversity of monumental fountains. Full article
(This article belongs to the Special Issue Discovery and Research on Aquatic Microorganisms)
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Article
Performance Analysis of Fully Actuated Multirotor Unmanned Aerial Vehicle Configurations with Passively Tilted Rotors
Appl. Sci. 2021, 11(18), 8786; https://0-doi-org.brum.beds.ac.uk/10.3390/app11188786 - 21 Sep 2021
Viewed by 443
Abstract
Unmanned aerial vehicles (UAVs) nowadays represent an interesting tool capable of performing various missions. The multirotor type of UAV is proven to be a potential solution in missions that require precise movements, such as environmental objects manipulation. In this paper, a procedure for [...] Read more.
Unmanned aerial vehicles (UAVs) nowadays represent an interesting tool capable of performing various missions. The multirotor type of UAV is proven to be a potential solution in missions that require precise movements, such as environmental objects manipulation. In this paper, a procedure for the performance analysis of fully actuated multirotor UAV configurations is proposed. For this purpose, a configuration is described by a control allocation scheme and implemented in the software package which enables the analysis and control implementation of a real system. The parameter analysis of the passively tilted multirotor configurations is performed based on the characteristics of the electric propulsion units, and the allocation of propulsion forces is graphically shown. The results of the proposed procedure provide an insight into the capabilities of configurations and can ultimately be used to select the propulsion system components and parameters according to the requirements and constraints associated with the specific mission profile. An experimental aircraft was built, and custom firmware was created, which enable us to experimentally prove the feasibility of fully actuated and passively tilted configurations. Full article
(This article belongs to the Special Issue Advances in Electric Propulsion Technology)
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Article
Case Study of Solar Photovoltaic Power-Plant Site Selection for Infrastructure Planning Using a BIM-GIS-Based Approach
Appl. Sci. 2021, 11(18), 8785; https://0-doi-org.brum.beds.ac.uk/10.3390/app11188785 - 21 Sep 2021
Viewed by 502
Abstract
Evaluating the site-selection process for photovoltaic (PV) plants is essential for securing available areas for solar power plant installation in limited spaces. Although the vicinities of highway networks can be suitable for installing PV plants, in terms of economic feasibility, they have rarely [...] Read more.
Evaluating the site-selection process for photovoltaic (PV) plants is essential for securing available areas for solar power plant installation in limited spaces. Although the vicinities of highway networks can be suitable for installing PV plants, in terms of economic feasibility, they have rarely been investigated because the impacts of various factors, including geographic or weather patterns, have not been analyzed. In this respect, this study conducts a case study on selecting the site for PV-panel installation in the vicinity of a highway (e.g., slopes) by integrating geographic information system (GIS) and building information model (BIM) techniques. Using location (e.g., highways, lakes, rivers), monthly solar power output, and orographic (e.g., slope) data, suitable regions are identified with the geo-spatial analysis; then, the amount of power that can be generated is evaluated in the regions. For the proposed sites, the surface conditions and potential PV systems are transformed and visualized in a BIM environment. In the results, the power output at optimal sites selected from the case area was computed at a total of 8227 MWh and was transformed into solar-panel families in three-dimensional environments. Thus, this study may help to identify optimal sites for PV plants in the unused areas near highways. Full article
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Article
Effect of Different Forms of Sulfur Fertilization on Bioactive Components and Antioxidant Activity of White Cabbage (Brassica Oleracea L.)
Appl. Sci. 2021, 11(18), 8784; https://0-doi-org.brum.beds.ac.uk/10.3390/app11188784 - 21 Sep 2021
Viewed by 456
Abstract
Cruciferous vegetables are very popular in latitudes corresponding to central and eastern Europe. They are rich in bioactive compounds such as chlorophylls, carotenoids, and polyphenols. The type and quality of fertilization has a significant impact on their chemical composition. The aim of this [...] Read more.
Cruciferous vegetables are very popular in latitudes corresponding to central and eastern Europe. They are rich in bioactive compounds such as chlorophylls, carotenoids, and polyphenols. The type and quality of fertilization has a significant impact on their chemical composition. The aim of this study was to determine the impact of specific forms of sulfur fertilization on the chemical properties of white cabbage, and to explore the effect of storage conditions on its bioactive components and antioxidant activity. The research material was the late cultivar of white cabbage ‘Stonehead’, fertilized with a dose of 30 kg S·ha−1, administered in the form of elemental sulfur, ammonium sulfate, and potassium sulfate. Sulfur fertilization had a significant impact on the parameters selected for this study, and the form in which it was applied resulted in different effects on these individual parameters. For all parameters investigated, the effect of sulfur fertilization was detectable. Antioxidant properties, determined as both ABTS and DPPH radical-scavenging activities, were the highest in cabbage harvested from the plot treated with potassium sulfate Full article
(This article belongs to the Special Issue Antioxidant Activity of Fresh Fruit and Vegetable)
Article
Ultrafast Ultrasound-Derived Muscle Strain Measure Correlates with Carotid Local Pulse Wave Velocity in Habitual Resistance-Trained Individuals
Appl. Sci. 2021, 11(18), 8783; https://0-doi-org.brum.beds.ac.uk/10.3390/app11188783 - 21 Sep 2021
Viewed by 328
Abstract
Purpose: this study investigated the effects of the intensity of machine-based bicep curl resistance exercise on ultrafast ultrasound-derived muscle strain rate and carotid ultrafast pulse wave velocity (ufPWV), and examined the association between muscle strain rate, ufPWV, and established carotid [...] Read more.
Purpose: this study investigated the effects of the intensity of machine-based bicep curl resistance exercise on ultrafast ultrasound-derived muscle strain rate and carotid ultrafast pulse wave velocity (ufPWV), and examined the association between muscle strain rate, ufPWV, and established carotid function measures in habitual resistance-trained individuals. Methods: twenty-three young habitual resistance-trained males (age: 24 ± 1 year, body mass index = 24 ± 1 kg/m2) were recruited to participate in two bouts of acute bicep curl exercise. After one-repetition maximum determination (1RM), the participants were randomly assigned to engage in bicep curls at 40 or 80%1RM intensity (10 reps × five sets) by a crossover study design. The muscle strain rate of bicep muscle, carotid ufPWV during systole(ufPWV-sys), and diastole (ufPWV-dia) were obtained pre- and post-exercise. In addition, carotid function measures were calculated by obtained carotid diameter and central blood pressure changes. Results: compared with pre-exercise, the reduction in post-exercise muscle strain rate and its area under the curve of 80%1RM was greater than those of 40%1RM. Both ufPWV-sys and ufPWV-dia increased regardless of exercise intensity. Baseline bicep muscle strain rate correlated not only with ufPWV-sys (r = −0.71, p = 0.001), ufPWV-dia (r = −0.74, p = 0.001), but also carotid compliance (r = 0.49, p = 0.02), distensibility (r = 0.54, p = 0.01) and ß stiffness (r= −0.84, p < 0.0001). The ufPWVs also correlated with ß stiffness (r = 0.64–0.76, p = 0.01). Conclusion: muscle stiffness measured by ultrafast ultrasound elastography increases positively with resistance exercise intensity, and it appears to correlate with carotid ufPWV and established carotid function measures in habitual resistance-trained individuals. Full article
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Editorial
Archaeoecology. The Application of Palaeoenvironmental Sciences for the Reconstruction of Human–Environment Interactions
Appl. Sci. 2021, 11(18), 8782; https://0-doi-org.brum.beds.ac.uk/10.3390/app11188782 - 21 Sep 2021
Viewed by 342
Abstract
The study of human–environment interactions is one of the mainstream topics in archaeological research, with increasing interest in the context of current societal challenges concerning environmental shifts related to climate change, sea-level rise, extreme natural events and also the exponential increase in anthropisation [...] Read more.
The study of human–environment interactions is one of the mainstream topics in archaeological research, with increasing interest in the context of current societal challenges concerning environmental shifts related to climate change, sea-level rise, extreme natural events and also the exponential increase in anthropisation in recent decades [...] Full article
Communication
Ensuring Data Integrity in Databases with the Universal Basis of Relations
Appl. Sci. 2021, 11(18), 8781; https://0-doi-org.brum.beds.ac.uk/10.3390/app11188781 - 21 Sep 2021
Viewed by 338
Abstract
The objective of the paper was to reveal the main techniques and means of ensuring the integrity of data and persistent stored database modules implemented in accordance with the recommendations of the Clark–Wilson model as a methodological basis for building a system that [...] Read more.
The objective of the paper was to reveal the main techniques and means of ensuring the integrity of data and persistent stored database modules implemented in accordance with the recommendations of the Clark–Wilson model as a methodological basis for building a system that ensures integrity. The considered database was built according to the schema with the universal basis of relations. The mechanisms developed in the process of researching the problem of ensuring the integrity of the data and programs of such a database were based on the provisions of the relational database theory, the Row Level Security technology, the potential of the modern blockchain model, and the capabilities of the database management system on the platform of which databases with the universal basis of relations are implemented. The implementation of the proposed techniques and means, controlling the integrity of the database of stored elements, prevents their unauthorized modification by authorized subjects and hinders the introduction of changes by unauthorized subjects. As a result, the stored data and programs remain correct, unaltered, undistorted, and preserved. This means that databases built based on a schema with the universal basis of relations and supported by such mechanisms are protected in terms of integrity. Full article
(This article belongs to the Special Issue Advances in Information Security and Privacy)
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Review
Technological Perspective of Cyber Secure Smart Inverters Used in Power Distribution System: State of the Art Review
Appl. Sci. 2021, 11(18), 8780; https://0-doi-org.brum.beds.ac.uk/10.3390/app11188780 - 21 Sep 2021
Viewed by 485
Abstract
The purpose of smart grid architecture as compared to the conventional grid is to ensure more stability, reliability and bi-directional communication between the utility and the consumer. The deployment of the same has succeeded in improving the efficiency of the distribution systems and [...] Read more.
The purpose of smart grid architecture as compared to the conventional grid is to ensure more stability, reliability and bi-directional communication between the utility and the consumer. The deployment of the same has succeeded in improving the efficiency of the distribution systems and effective co-ordination and interoperability among the different components of the grid. Smart inverters play a major role in seamless grid integration, control and conversion of power when the renewable energy sources are present. However, they come with several security challenges as well, which are of considerable concern. Certain cyber threats include physical and cyber attacks, natural phenomena which in turn can lead to grid failure, blackouts, commercial energy losses, privacy and safety issues, etc. Therefore, there is a need for critical examination of all these issues which must be considered for designing cyber secure smart inverters at the distribution level. In this comprehensive review, keeping the technological perspective in mind, the existing gaps and the necessity for the same are highlighted. The various topologies, IEEE protocols and the control strategy are presented in detail. This will enable prospective researchers to address the design issues of smart inverters with greater focus on security and reliability aspects. Full article
(This article belongs to the Special Issue Advancements for Large Scale Adoption of Smart-Inverters)
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Article
A Compact Sequentially Rotated Circularly Polarized Dielectric Resonator Antenna Array
Appl. Sci. 2021, 11(18), 8779; https://0-doi-org.brum.beds.ac.uk/10.3390/app11188779 - 21 Sep 2021
Viewed by 439
Abstract
In this study, a compact 2 × 2 circularly polarized (CP) sequentially rotated (SR) dielectric resonator antenna (DRA) array operating in the IEEE 802.11a band is presented. To acquire the CP radiation, an elliptical slot (ES) was introduced to couple a rectangular dielectric [...] Read more.
In this study, a compact 2 × 2 circularly polarized (CP) sequentially rotated (SR) dielectric resonator antenna (DRA) array operating in the IEEE 802.11a band is presented. To acquire the CP radiation, an elliptical slot (ES) was introduced to couple a rectangular dielectric resonator (RDR). The ES generates two resonant frequencies corresponding to the dominant even and odd modes. The SR feeder is made of four quarter-wavelength microstrip transformers to reduce the input impedance of the elements and, consequently, maximize the power transferred to each element. Experimental and simulation verifications were conducted on a 54 × 50 × 0.813 mm3 prototype to evaluate the performance of the proposed antenna array, which achieved a VSWR < −10 dB bandwidth of 1 GHz (5.1–6.05 GHz) and axial ratio (AR) < 3 dB of 0.95 GHz (5.1–5.85 GHz). The agreement between the simulated and measured results confirmed the validity of the proposed design. Full article
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Article
Recycled Tire Rubber in Additive Manufacturing: Selective Laser Sintering for Polymer-Ground Rubber Composites
Appl. Sci. 2021, 11(18), 8778; https://0-doi-org.brum.beds.ac.uk/10.3390/app11188778 - 21 Sep 2021
Viewed by 555
Abstract
Natural and synthetic rubber is gaining increased interest in various industrial applications and daily life sectors (automotive industry, acoustic and electrical isolators, adhesives, impermeable surfaces, and others) due to its remarkable physicomechanical properties, excellent durability, and abrasive resistance. These great characteristics are accompanied [...] Read more.
Natural and synthetic rubber is gaining increased interest in various industrial applications and daily life sectors (automotive industry, acoustic and electrical isolators, adhesives, impermeable surfaces, and others) due to its remarkable physicomechanical properties, excellent durability, and abrasive resistance. These great characteristics are accompanied by some recycling difficulties of the final products, particularly originated from the tire waste rubber industry. In this study, recycled tire rubber was incorporated in polymer matrices using selective laser sintering as 3D printing technology. Two polymers were used-polyamide and thermoplastic polyurethane, for their rigid and elastomeric properties, respectively. Polymer composites containing various tire powder amounts, up to 40 wt.%, were prepared by physical blending. The final materials’ morphological characteristics, mechanical properties, and thermal stability were evaluated. The proposed ambitious additive manufacturing approach looked over also some of the major aspects to be considered during the 3D printing procedure. In addition, examples of printed prototypes with potential applications were also proposed revealing the potential of the recycled tire rubber-loaded composites. Full article
(This article belongs to the Special Issue Advances in Additive Manufacturing Technology)
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Article
Optimization of Storage Medium for Hematological Reference Samples in External Quality Assessment
Appl. Sci. 2021, 11(18), 8777; https://0-doi-org.brum.beds.ac.uk/10.3390/app11188777 - 21 Sep 2021
Viewed by 361
Abstract
Hematological reference samples for external quality assessment (EQA) in hematology are essential for many laboratories in Vietnam, however, the prices are high along with short storing time. This study attempted to establish an optimal formula for the manufacture of hematological reference samples for [...] Read more.
Hematological reference samples for external quality assessment (EQA) in hematology are essential for many laboratories in Vietnam, however, the prices are high along with short storing time. This study attempted to establish an optimal formula for the manufacture of hematological reference samples for hematological EQA programs. Human red blood cells (RBCs) were mixed with goose RBCs (pseudo-leucocytes) and goat RBCs (pseudo-platelets) as alternatives for white blood cells (WBCs) and platelets (PLTs), respectively, in different formulas of storage media. The optimal formula was obtained using response surface methodology–central composite design (RSM-CCD). Three main factors affecting the concentrations of RBCs were determined by Plackett–Burmann matrix. The optimal concentrations determined by RSM-CCD were 46% serum, 0.44 g/L neomycin sulfate, and 2.5% glycerol. The model predicted that the maximum number of human RBCs was 4.1 × 1012 cells/L, pseudo-leucocytes was 6.4 × 109 cells/L, and pseudo-platelets was 188 × 109 cells/L. The practical concentrations of RBCs, pseudo-leucocytes, and pseudo-platelets were 4.21 × 1012 cells/L, 6.4 × 109 cells/L, and 187 × 109 cells/L, respectively, which showed 98.93% similarity with theoretical data. This result could be a premise for further study to improve manufacturing of hematological reference samples for hematology EQA programs. Full article
(This article belongs to the Section Biomedical Engineering)
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Article
Speech Characteristics as Indicators of Personality Traits
Appl. Sci. 2021, 11(18), 8776; https://0-doi-org.brum.beds.ac.uk/10.3390/app11188776 - 21 Sep 2021
Viewed by 472
Abstract
This study examines the relationship between speech characteristics and personality traits by drawing on pseudo-naturalistic conversations and on personality dimensions identified by the Myers–Briggs Type Indicator (MBTI) model which assesses four personality dimensions of introversion-extroversion, sensing-intuiting, thinking-feeling, and judging-perceiving. The speech of 30 [...] Read more.
This study examines the relationship between speech characteristics and personality traits by drawing on pseudo-naturalistic conversations and on personality dimensions identified by the Myers–Briggs Type Indicator (MBTI) model which assesses four personality dimensions of introversion-extroversion, sensing-intuiting, thinking-feeling, and judging-perceiving. The speech of 30 participants was recorded and transcribed, after which a number of speech features including pitch, loudness, response time (i.e., how fast one responds to a prompt), speech rate, and discourse markers were extracted and analyzed. Results show that several speech features correspond to different personality dimensions. Specifically, speech rate as measured by words per minute reveals significant differences between judging individuals and perceiving individuals (perceiving individuals speak faster than judging individuals); there is a significant difference in response time for extroverts and introverts (extroverts respond faster); a significant difference is observed in loudness between judging and perceiving individuals (judging individuals are louder). The frequency of discourse markers is significantly higher for intuiting individuals than sensing individuals. The study discusses these findings in further inquiring the relationship between language and personality. Full article
(This article belongs to the Special Issue Novel Approaches and Applications in Ergonomic Design II)
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Article
Resonant X-ray Emission Spectroscopy with a SASE Beam
Appl. Sci. 2021, 11(18), 8775; https://0-doi-org.brum.beds.ac.uk/10.3390/app11188775 - 21 Sep 2021
Viewed by 411
Abstract
Aqueous iron (III) oxide nanoparticles were irradiated with pure self-amplified spontaneous emission (SASE) X-ray free-electron laser (XFEL) pulses tuned to the energy around the Fe K-edge ionization threshold. For each XFEL shot, the incident X-ray pulse spectrum and Fe Kβ emission spectrum were [...] Read more.
Aqueous iron (III) oxide nanoparticles were irradiated with pure self-amplified spontaneous emission (SASE) X-ray free-electron laser (XFEL) pulses tuned to the energy around the Fe K-edge ionization threshold. For each XFEL shot, the incident X-ray pulse spectrum and Fe Kβ emission spectrum were measured synchronously with dedicated spectrometers and processed through a reconstruction algorithm allowing for the determination of Fe Kβ resonant X-ray emission spectroscopy (RXES) plane with high energy resolution. The influence of the number of X-ray shots employed in the experiment on the reconstructed data quality was evaluated, enabling the determination of thresholds for good data acquisition and experimental times essential for practical usage of scarce XFEL beam times. Full article
(This article belongs to the Special Issue Latest Trends in Free Electron Lasers)
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Article
Comparison of Optimal Control Designs for a 5 MW Wind Turbine
Appl. Sci. 2021, 11(18), 8774; https://0-doi-org.brum.beds.ac.uk/10.3390/app11188774 - 21 Sep 2021
Viewed by 337
Abstract
Optimal controllers, namely Model Predictive Control (MPC), H Control (H), and Linear Quadratic Gaussian control (LQG), are designed for a 5 MW horizontal-axis variable-speed wind turbine. The control design models required as part of the optimal control design are [...] Read more.
Optimal controllers, namely Model Predictive Control (MPC), H Control (H), and Linear Quadratic Gaussian control (LQG), are designed for a 5 MW horizontal-axis variable-speed wind turbine. The control design models required as part of the optimal control design are obtained by using a high fidelity aeroelastic model (i.e., DNV Bladed). The optimal controllers are eventually designed in three operating modes: below-rated, just below-rated, and above rated-wind speeds, based on linearized control design models. The linearized models are reduced by using a model reduction technique to facilitate the design of optimal controllers. The controllers are analyzed not only in the time domain but also in the frequency domain and on the torque/speed plane. Simulation results demonstrated that optimal controllers perform better than the standard proportional-integral-derivative (PID) controller, particularly for removing oscillation due to the drive-train mode without incorporating a drive-train damper. Full article
(This article belongs to the Special Issue Boosting Wind Power Integration)
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Article
Modeling of Metabolic Equivalents (METs) during Moderate Resistance Training Exercises
Appl. Sci. 2021, 11(18), 8773; https://0-doi-org.brum.beds.ac.uk/10.3390/app11188773 - 21 Sep 2021
Viewed by 481
Abstract
Energy expenditure through metabolic equivalent (MET) prediction during resistance exercises in humans can be modeled by using cardiorespiratory parameters. In this study, we aimed to predict MET during six moderate-intensity resistance training sessions consisting of three different exercises. Eleven participants were recruited into [...] Read more.
Energy expenditure through metabolic equivalent (MET) prediction during resistance exercises in humans can be modeled by using cardiorespiratory parameters. In this study, we aimed to predict MET during six moderate-intensity resistance training sessions consisting of three different exercises. Eleven participants were recruited into two groups; an untrained (n = 5; with no resistance training experience) and a trained group (n = 6; with 2 months resistance training experience). Each participant completed six training sessions separated with a rest interval of 1–2 days. While wearing a mask for indirect calorimetric measurements using Cortex Metalyzer 3B, each participant performed training sessions consisting of three types of dumbbell exercises: shoulder press, deadlift, and squat. The metabolic equivalents (METs), respiratory exchange ratio (RER), heart rate (HR), systolic blood pressure (SBP), diastolic blood pressure (DBP), blood lactate (BL), and Borg rate of perceived exertion (RPE) were measured. The MET was predicted using generalized estimating equations (GEE) for repeated measure data collected during exercise and rest periods. It was observed that during exercise period, RER, HR, SBP, and BL for the training group (QIC = 187, 95% CI = −0.012~0.915, p = 0.000*~0.033*) while RER, HR, SBP, DBP, and RPE (QIC = 48, 95% CI = −0.024~0.422, p = 0.000*~0.002*) during resting period for untrained group significantly predicted MET for moderate-intensity interval resistance training. It is concluded that the cardiorespiratory variables are significantly related to MET. During exercise, RER and HR significantly predicted MET for both groups along with additional parameters of SBP and BL for the training group. While during the resting period, RER, HR, SBP, DBP, and RPE related significantly for untrained and BL for training group respectively. Full article
(This article belongs to the Special Issue Sports and Exercise Rehabilitation)
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Article
Improving the Discriminability of Haptic Icons: The Haptic Tuning Fork
Appl. Sci. 2021, 11(18), 8772; https://0-doi-org.brum.beds.ac.uk/10.3390/app11188772 - 21 Sep 2021
Viewed by 299
Abstract
Technological advances enable the capture and management of complex data sets that need to be correctly understood. Visualisation techniques can help in complex data analysis and exploration, but sometimes the visual channel is not enough, or it is not always available. Some authors [...] Read more.
Technological advances enable the capture and management of complex data sets that need to be correctly understood. Visualisation techniques can help in complex data analysis and exploration, but sometimes the visual channel is not enough, or it is not always available. Some authors propose using the haptic channel to reinforce or substitute the visual sense, but the limited human haptic short-term memory still poses a challenge. We present the haptic tuning fork, a reference signal displayed before the haptic information for increasing the discriminability of haptic icons. With this reference, the user does not depend only on short-term memory. We have decided to evaluate the usefulness of the haptic tuning fork in impedance kinesthetic devices as these are the most common. Furthermore, since the renderable signal ranges are device-dependent, we introduce a methodology to select a discriminable set of signals called the haptic scale. Both the haptic tuning fork and the haptic scale proved their usefulness in the performed experiments regarding haptic stimuli varying in frequency. Full article
(This article belongs to the Special Issue Haptics: Technology and Applications2021)
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Article
The Intake of Pain Medication among Dentists and Dental Assistants with Musculoskeletal Disorders in Germany
Appl. Sci. 2021, 11(18), 8771; https://0-doi-org.brum.beds.ac.uk/10.3390/app11188771 - 21 Sep 2021
Viewed by 491
Abstract
Background: Dentists (Ds) and dental assistants (DAs) have a high lifetime prevalence of musculoskeletal disorders (MSDs). In this context, it is assumed that they have an increased intake of substances such as pain medication. Currently, there exist no data on the use of [...] Read more.
Background: Dentists (Ds) and dental assistants (DAs) have a high lifetime prevalence of musculoskeletal disorders (MSDs). In this context, it is assumed that they have an increased intake of substances such as pain medication. Currently, there exist no data on the use of medication among Ds and DAs with MSDs in Germany. Methods: The online questionnaire (i.e., the Nordic Questionnaire) analysed the medical therapies used by 389 Ds (240 f/149 m) and 406 DAs (401 f/5 m) to treat their MSDs. Results: Ds (28.3–11.5%) and DAs (29.4–10.3%) with MSDs took medication depending on the affected body region. A trend between the Ds and DAs in the intake of drug therapy and the frequency was found for the neck region (Ds: 21.1%, DAs: 28.7%). A single medication was taken most frequently (Ds: 60.0–33.3%, DAs: 71.4–27.3%). The frequency of use varied greatly for both occupational groups depending on the region affected. Conclusion: Ds and DAs perceived the need for medical therapies because of their MSDs. Painkillers such as ibuprofen and systemic diclofenac were the medications most frequently taken by both occupational groups. The intake of pain killers, most notably for the neck, should prevent sick leave. Full article
(This article belongs to the Section Applied Dentistry and Oral Sciences)
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Article
ARK-BIM: Open-Source Cloud-Based HBIM Platform for Archaeology
Appl. Sci. 2021, 11(18), 8770; https://0-doi-org.brum.beds.ac.uk/10.3390/app11188770 - 21 Sep 2021
Cited by 1 | Viewed by 464
Abstract
In recent years, Historic Building Information Modelling (HBIM) methodology has strengthened the documentation and interpretation of archaeological contexts and is regarded as a breakthrough in relation to established methodologies and analyses. Change is also taking place regarding web and cloud-based solutions, and this [...] Read more.
In recent years, Historic Building Information Modelling (HBIM) methodology has strengthened the documentation and interpretation of archaeological contexts and is regarded as a breakthrough in relation to established methodologies and analyses. Change is also taking place regarding web and cloud-based solutions, and this work acknowledges the importance of cloud-based and web HBIM solutions applied to Cultural Heritage assets and archaeology. More than ever, online platforms are becoming useful services to ease data exchange and validation between collaborators and stakeholders, establishing multidisciplinary approaches. Despite the presence of different cloud-based platforms, Heritage asset documentation can hardly be managed by environments or software developed for architecture and construction design. For this reason, this project is strongly founded on four pillars: online documentation, collaboration, communication and accessibility. Cognisant of these needs, the paper is aimed at the development of a custom HBIM cloud platform for archaeology, on the basis of the BIMData open-source online environment. This platform, called ARK-BIM, can be considered a modular solution leaning on HTML, JavaScript, VueJS, XEOKIT and open-source languages. Full article
(This article belongs to the Special Issue 3D Virtual Reconstruction for Archaeological Sites)
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Article
Discrete Semantics-Guided Asymmetric Hashing for Large-Scale Multimedia Retrieval
Appl. Sci. 2021, 11(18), 8769; https://0-doi-org.brum.beds.ac.uk/10.3390/app11188769 - 21 Sep 2021
Viewed by 370
Abstract
Cross-modal hashing technology is a key technology for real-time retrieval of large-scale multimedia data in real-world applications. Although the existing cross-modal hashing methods have achieved impressive accomplishment, there are still some limitations: (1) some cross-modal hashing methods do not make full consider the [...] Read more.
Cross-modal hashing technology is a key technology for real-time retrieval of large-scale multimedia data in real-world applications. Although the existing cross-modal hashing methods have achieved impressive accomplishment, there are still some limitations: (1) some cross-modal hashing methods do not make full consider the rich semantic information and noise information in labels, resulting in a large semantic gap, and (2) some cross-modal hashing methods adopt the relaxation-based or discrete cyclic coordinate descent algorithm to solve the discrete constraint problem, resulting in a large quantization error or time consumption. Therefore, in order to solve these limitations, in this paper, we propose a novel method, named Discrete Semantics-Guided Asymmetric Hashing (DSAH). Specifically, our proposed DSAH leverages both label information and similarity matrix to enhance the semantic information of the learned hash codes, and the 2,1 norm is used to increase the sparsity of matrix to solve the problem of the inevitable noise and subjective factors in labels. Meanwhile, an asymmetric hash learning scheme is proposed to efficiently perform hash learning. In addition, a discrete optimization algorithm is proposed to fast solve the hash code directly and discretely. During the optimization process, the hash code learning and the hash function learning interact, i.e., the learned hash codes can guide the learning process of the hash function and the hash function can also guide the hash code generation simultaneously. Extensive experiments performed on two benchmark datasets highlight the superiority of DSAH over several state-of-the-art methods. Full article
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Article
An Enhanced Photonic Quantum Finite Automaton
Appl. Sci. 2021, 11(18), 8768; https://0-doi-org.brum.beds.ac.uk/10.3390/app11188768 - 21 Sep 2021
Viewed by 286
Abstract
In a recent paper we have described an optical implementation of a measure-once one-way quantum finite automaton recognizing a well-known family of unary periodic languages, accepting words not in the language with a given error probability. To process input words, the automaton exploits [...] Read more.
In a recent paper we have described an optical implementation of a measure-once one-way quantum finite automaton recognizing a well-known family of unary periodic languages, accepting words not in the language with a given error probability. To process input words, the automaton exploits the degree of polarization of single photons and, to reduce the acceptance error probability, a technique of confidence amplification using the photon counts is implemented. In this paper, we show that the performance of this automaton may be further improved by using strategies that suitably consider both the orthogonal output polarizations of the photon. In our analysis, we also take into account how detector dark counts may affect the performance of the automaton. Full article
(This article belongs to the Special Issue Basics and Applications in Quantum Optics)
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Article
SPIN: A Blockchain-Based Framework for Sharing COVID-19 Pandemic Information across Nations
Appl. Sci. 2021, 11(18), 8767; https://0-doi-org.brum.beds.ac.uk/10.3390/app11188767 - 21 Sep 2021
Viewed by 358
Abstract
The COVID-19 pandemic has caused many countries around the globe to put strict policies and measures in place in an attempt to control the rapid spread of the virus. These measures have affected economic activities and have impacted a broad range of businesses, [...] Read more.
The COVID-19 pandemic has caused many countries around the globe to put strict policies and measures in place in an attempt to control the rapid spread of the virus. These measures have affected economic activities and have impacted a broad range of businesses, such as international traveling, restaurants, and shopping malls. As COVID-19 vaccination efforts progress, countries are starting to relax international travel constraints and permit passengers from certain destinations to cross the border. Moreover, travelers from those destinations are likely required to provide certificates of vaccination results or negative COVID-19 tests before crossing the borders. Implementing these travel guidelines requires sharing information between countries, such as the number of COVID-19 cases and vaccination certificates for travelers. In this paper, we introduce SPIN, a framework leveraging a permissioned blockchain for sharing COVID-19 information between countries. This includes public data, such as the number of vaccinated people, and private data, such as vaccination certificates for individuals. Additionally, we employ cancelable fingerprint templates to authenticate private information about travelers. We analyze the framework from scalability, efficiency, security, and privacy perspectives. To validate our framework, we provide a prototype implementation using the Hyperledger Fabric platform. Full article
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Article
Declining Effect of Precipitation on the Normalized Difference Vegetation Index of Grasslands in the Inner Mongolian Plateau, 1982–2010
Appl. Sci. 2021, 11(18), 8766; https://0-doi-org.brum.beds.ac.uk/10.3390/app11188766 - 21 Sep 2021
Viewed by 371
Abstract
Grasslands play an irreplaceable role in maintaining carbon balance and stabilizing the entire Earth’s ecosystem. Although the grasslands in Inner Mongolia are sensitive and vulnerable to climate change, a generalized effect of climate change on the grasslands is still unavailable. In this study, [...] Read more.
Grasslands play an irreplaceable role in maintaining carbon balance and stabilizing the entire Earth’s ecosystem. Although the grasslands in Inner Mongolia are sensitive and vulnerable to climate change, a generalized effect of climate change on the grasslands is still unavailable. In this study, we analyzed the effects of annual mean precipitation and annual mean temperature on the normalized difference vegetation index from 1982 to 2010 on the Inner Mongolia Plateau. Our results indicated that the normalized difference vegetation index was mostly affected by precipitation, followed by temperature. Spatially, temperature and precipitation had greater effects on normalized difference vegetation index in dry regions than in wet ones. In time series, the effect of precipitation on normalized difference vegetation index had significantly decreased from 1982 to 2010 (R2 = 0.11, p > 0.05). However, the effect of temperature on normalized difference vegetation index remained stable. The high variation effect of precipitation on normalized difference vegetation index was due to the significant decrease in precipitation from 1980 to 2010. Thus, 35.47% and 0.56% of the dynamic of normalized difference vegetation index from 1982 to 2010 was accounted for by the precipitation and temperature, respectively. Our findings highlighted that grasslands are adaptable to the significant increase in temperature, but are sensitive to the decrease in precipitation on the Inner Mongolia Plateau. Full article
(This article belongs to the Special Issue Remote Sensing and GIS in Environmental Monitoring)
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Article
Analysis of Running Performance in the Offensive and Defensive Phases of the Game: Is It Associated with the Team Achievement in the UEFA Champions League?
Appl. Sci. 2021, 11(18), 8765; https://0-doi-org.brum.beds.ac.uk/10.3390/app11188765 - 21 Sep 2021
Viewed by 569
Abstract
Although associations between running performance (RP) with ball possession and team achievement in soccer are often hypothesized, actual knowledge of this association in elite soccer remains limited. Therefore, this study aimed to evaluate players’ RPs according to ball possession to determine its possible [...] Read more.
Although associations between running performance (RP) with ball possession and team achievement in soccer are often hypothesized, actual knowledge of this association in elite soccer remains limited. Therefore, this study aimed to evaluate players’ RPs according to ball possession to determine its possible influence on team achievement in the UEFA Champions League (UCL). The players’ RPs (n = 244) were collected during UCL group stage matches (n = 20) in the 2020/21 season using the semiautomatic video system InStat Fitness. Then, players’ RPs were classified according to the specific playing position: central defenders (CD; n = 79), fullbacks (FB; n = 65), central midfielders (CM; n = 55), wide midfielders (WM; n = 28) and forwards (FW; n = 17). RPs were observed in the attacking phase (AP, i.e., when the team was in possession of the ball) and defensive phase (DP, i.e., when the team did not have possession of the ball) of the game, and included the total distance covered (m) and distance covered in different categories: walking (<7.1 km/h), jogging (7.1–14.3 km/h), running (14.4–19.7 km/h), high-intensity running (>19.8 km/h), high-speed running (19.8–25.1 km/h) and sprinting (>25.2 km/h). Team achievement was defined by the total group points earned (TGP) at the end of the group phase of the UCL and by match outcome (win, draw, loss) of single matches. The results indicated that the total, walking and jogging distances covered were negatively and positively associated with TGP (Pearson’s correlations from 0.30 to 0.73; all p < 0.05) in the AP and DP of the game, respectively. Won matches were characterized by significantly lower and higher values of total, walking and jogging distances covered in AP and DP of the game, respectively (F tests: from 7.15 to 22.5, all p < 0.01; all small to medium effect sizes). In addition, RPs in the AP and DP of the game explained only 37.2% of the variance in the TGP. These findings demonstrate that the influence of RP on team achievement in UCL is limited in both the AP and DP of the game. Full article
(This article belongs to the Special Issue Performance Analysis in Sport and Exercise)
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Review
Recent Advances on Machine Learning Applications in Machining Processes
Appl. Sci. 2021, 11(18), 8764; https://0-doi-org.brum.beds.ac.uk/10.3390/app11188764 - 21 Sep 2021
Viewed by 461
Abstract
This study aims to present an overall review of the recent research status regarding Machine Learning (ML) applications in machining processes. In the current industrial systems, processes require the capacity to adapt to manufacturing conditions continuously, guaranteeing high performance in terms of production [...] Read more.
This study aims to present an overall review of the recent research status regarding Machine Learning (ML) applications in machining processes. In the current industrial systems, processes require the capacity to adapt to manufacturing conditions continuously, guaranteeing high performance in terms of production quality and equipment availability. Artificial Intelligence (AI) offers new opportunities to develop and integrate innovative solutions in conventional machine tools to reduce undesirable effects during operational activities. In particular, the significant increase of the computational capacity may permit the application of complex algorithms to big data volumes in a short time, expanding the potentialities of ML techniques. ML applications are present in several contexts of machining processes, from roughness quality prediction to tool condition monitoring. This review focuses on recent applications and implications, classifying the main problems that may be solved using ML related to the machining quality, energy consumption and conditional monitoring. Finally, a discussion on the advantages and limits of ML algorithms is summarized for future investigations. Full article
Article
Toward a Mechanism for the Emergence of Gravity
Appl. Sci. 2021, 11(18), 8763; https://0-doi-org.brum.beds.ac.uk/10.3390/app11188763 - 21 Sep 2021
Viewed by 421
Abstract
One of the main problems that emergent-gravity approaches face is explaining how a system that does not contain gauge symmetries ab initio might develop them effectively in some regime. We review a mechanism introduced by some of the authors for the emergence of [...] Read more.
One of the main problems that emergent-gravity approaches face is explaining how a system that does not contain gauge symmetries ab initio might develop them effectively in some regime. We review a mechanism introduced by some of the authors for the emergence of gauge symmetries in [JHEP 10 (2016) 084] and discuss how it works for interacting Lorentz-invariant vector field theories as a warm-up exercise for the more convoluted problem of gravity. Then, we apply this mechanism to the emergence of linear diffeomorphisms for the most general Lorentz-invariant linear theory of a two-index symmetric tensor field, which constitutes a generalization of the Fierz–Pauli theory describing linearized gravity. Finally we discuss two results, the well-known Weinberg–Witten theorem and a more recent theorem by Marolf, that are often invoked as no-go theorems for emergent gravity. Our analysis illustrates that, although these results pinpoint some of the particularities of gravity with respect to other gauge theories, they do not constitute an impediment for the emergent gravity program if gauge symmetries (diffeomorphisms) are emergent in the sense discussed in this paper. Full article
(This article belongs to the Special Issue Analogue Gravitational Dynamics)
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Article
Optimum Design of Flexural Strength and Stiffness for Reinforced Concrete Beams Using Machine Learning
Appl. Sci. 2021, 11(18), 8762; https://0-doi-org.brum.beds.ac.uk/10.3390/app11188762 - 20 Sep 2021
Viewed by 624
Abstract
In this paper, an optimization approach was presented for the flexural strength and stiffness design of reinforced concrete beams. Surrogate modeling based on machine learning was applied to predict the responses of the structural system in three-point flexure tests. Three design input variables, [...] Read more.
In this paper, an optimization approach was presented for the flexural strength and stiffness design of reinforced concrete beams. Surrogate modeling based on machine learning was applied to predict the responses of the structural system in three-point flexure tests. Three design input variables, the area of steel bars in the compression zone, the area of steel bars in the tension zone, and the area of steel bars in the shear zone, were adopted for the dataset and arranged by the Box-Behnken design method. The dataset was composed of thirteen specimens of reinforced concrete beams. The specimens were tested under three-point flexure loading at the age of 28 days and both the failure load and the maximum deflection values were recorded. Compression and tension tests were conducted to obtain the concrete data for the analysis and numerical modeling. Afterward, finite element modeling was performed for all the specimens using the ATENA program to verify the experimental tests. Subsequently, the surrogate models for the flexural strength and the stiffness were constructed. Finally, optimization was conducted supporting on the factorial method for the predicted responses. The adopted approach proved to be an excellent tool to optimize the design of reinforced concrete beams for flexure and stiffness. In addition, experimental and numerical results were in very good agreement in terms of both the failure type and the cracking pattern. Full article
(This article belongs to the Special Issue Novel Computing Methods for Machine Learning)
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Article
Dimension Reduction Using New Bond Graph Algorithm and Deep Learning Pooling on EEG Signals for BCI
Appl. Sci. 2021, 11(18), 8761; https://0-doi-org.brum.beds.ac.uk/10.3390/app11188761 - 20 Sep 2021
Viewed by 415
Abstract
One of the main challenges in studying brain signals is the large size of the data due to the use of many electrodes and the time-consuming sampling. Choosing the right dimensional reduction method can lead to a reduction in the data processing time. [...] Read more.
One of the main challenges in studying brain signals is the large size of the data due to the use of many electrodes and the time-consuming sampling. Choosing the right dimensional reduction method can lead to a reduction in the data processing time. Evolutionary algorithms are one of the methods used to reduce the dimensions in the field of EEG brain signals, which have shown better performance than other common methods. In this article, (1) a new Bond Graph algorithm (BGA) is introduced that has demonstrated better performance on eight benchmark functions compared to genetic algorithm and particle swarm optimization. Our algorithm has fast convergence and does not get stuck in local optimums. (2) Reductions of features, electrodes, and the frequency range have been evaluated simultaneously for brain signals (left-handed and right-handed). BGA and other algorithms are used to reduce features. (3) Feature extraction and feature selection (with algorithms) for time domain, frequency domain, wavelet coefficients, and autoregression have been studied as well as electrode reduction and frequency interval reduction. (4) First, the features/properties (algorithms) are reduced, the electrodes are reduced, and the frequency range is reduced, which is followed by the construction of new signals based on the proposed formulas. Then, a Common Spatial Pattern is used to remove noise and feature extraction and is classified by a classifier. (5) A separate study with a deep sampling method has been implemented as feature selection in several layers with functions and different window sizes. This part is also associated with reducing the feature and reducing the frequency range. All items expressed in data set IIa from BCI competition IV (the left hand and right hand) have been evaluated between one and three channels, with better results for similar cases (in close proximity). Our method demonstrated an increased accuracy by 5 to 8% and an increased kappa by 5%. Full article
(This article belongs to the Special Issue Artificial Intelligence on Brain–Computer Interface (BCI))
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Article
A Novel Slicing Strategy to Print Overhangs without Support Material
Appl. Sci. 2021, 11(18), 8760; https://0-doi-org.brum.beds.ac.uk/10.3390/app11188760 - 20 Sep 2021
Viewed by 484
Abstract
Fused deposition modeling (FDM) 3D printers commonly need support material to print overhangs. A previously developed 4-axis printing process based on an orthogonal kinematic, an additional rotational axis around the z-axis and a 45° tilted nozzle can print overhangs up to 100° without [...] Read more.
Fused deposition modeling (FDM) 3D printers commonly need support material to print overhangs. A previously developed 4-axis printing process based on an orthogonal kinematic, an additional rotational axis around the z-axis and a 45° tilted nozzle can print overhangs up to 100° without support material. With this approach, the layers are in a conical shape and no longer parallel to the printing plane; therefore, a new slicer strategy is necessary to generate the paths. This paper describes a slicing algorithm compatible with this 4-axis printing kinematics. The presented slicing strategy is a combination of a geometrical transformation with a conventional slicing software and has three basic steps: Transformation of the geometry in the .STL file, path generation with a conventional slicer and back transformation of the G-code. A comparison of conventionally manufactured parts and parts produced with the new process shows the feasibility and initial results in terms of surface quality and dimensional accuracy. Full article
(This article belongs to the Special Issue Advances in Additive Manufacturing Technology)
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