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Applied Sciences
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Selected Papers from IMETI 2020
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Selected Papers from IMETI 2020

A special issue of Applied Sciences (ISSN 2076-3417).

Deadline for manuscript submissions: closed (31 July 2021) | Viewed by 77619

Special Issue Editors

Prof. Dr. Wen-Hsiang Hsieh

E-Mail Website
Guest Editor
Department of Automation Engineering, National Formosa University, Huwei, Yunlin 632, Taiwan
Interests: innovative applications of mechanisms; mechatronics; automatic machinery
Special Issues, Collections and Topics in MDPI journals
Prof. Dr. Minvydas Ragulskis

E-Mail Website
Guest Editor
Department of Mathematical Modelling, Kaunas University of Technology, LT-51368 Kaunas, Lithuania
Interests: development of numerical methods; modelling of optical effects; visual cryptography; nonlinear dynamical systems and chaos
Special Issues, Collections and Topics in MDPI journals
Prof. Dr. Jia-Shing Sheu

E-Mail Website
Guest Editor
Department of Computer Science, National Taipei University of Education, Taipei, Taiwan
Interests: signal processing; pattern recognition and image processing; real time face recognition; embedded system
Special Issues, Collections and Topics in MDPI journals

Special Issue Information

Dear Colleagues,

The 9th International Multi-Conference on Engineering and Technology Innovation (IMETI 2020) will be held in Taichung, Taiwan, 23–27 October 2020. It covers a wide range of fields in science and engineering innovation and aims to bring together engineering technology expertise. Professionals from the industry, academia, and government in discourse on research and development and professional practice, business, and management in the science and engineering fields are welcome to attend the event. IMETI2020 consists of the 3 sub-conferences (ICATI 2020, ICBEI 2020, ICECEI 2020) and more than 30 regular and special sessions (http://imeti.org/IMETI2020/).

The main goal of this Special Issue, “Selected Papers from IMETII 2020”, is to present the latest advances in research and novel applications of engineering and technology, especially Artificial Intelligence (AI), Materials Science, Civil Engineering, Industry 4.0, Mechatronic Engineering, Intelligent Computing and System, Computer and Information Engineering, and Green Technology and New Energy. Potential topics include but are not limited to:

  • Artificial intelligence
  • Materials science
  • Mechatronic and robotics engineering
  • Electrical and electronic engineering
  • Optical engineering
  • Civil engineering
  • Chemical and biomedical engineering
  • Computer and information engineering
  • Green technology, new energy, and civil engineering
  • Industry 4.0 and automation engineering
  • Control engineering
  • Mechanical engineering
  • Nanotechnology
  • Environmental, food, health science, and technology
  • Intelligent computing and system
Prof. Dr. Wen-Hsiang Hsieh
Prof. Dr. Minvydas Ragulskis
Prof. Dr. Jia-Shing Sheu
Guest Editors

Manuscript Submission Information

Manuscripts should be submitted online at www.mdpi.com by registering and logging in to this website. Once you are registered, click here to go to the submission form. Manuscripts can be submitted until the deadline. All submissions that pass pre-check are peer-reviewed. Accepted papers will be published continuously in the journal (as soon as accepted) and will be listed together on the special issue website. Research articles, review articles as well as short communications are invited. For planned papers, a title and short abstract (about 100 words) can be sent to the Editorial Office for announcement on this website.

Submitted manuscripts should not have been published previously, nor be under consideration for publication elsewhere (except conference proceedings papers). All manuscripts are thoroughly refereed through a single-blind peer-review process. A guide for authors and other relevant information for submission of manuscripts is available on the Instructions for Authors page. Applied Sciences is an international peer-reviewed open access semimonthly journal published by MDPI.

Please visit the Instructions for Authors page before submitting a manuscript. The Article Processing Charge (APC) for publication in this open access journal is 2400 CHF (Swiss Francs). Submitted papers should be well formatted and use good English. Authors may use MDPI's English editing service prior to publication or during author revisions.

Keywords

  • IMETI, ICATI, ICBEI, ICECEI
  • Artificial intelligence
  • Industry 4.0
  • Intelligent computing and system
  • Green technology
  • Materials
  • Mechatronic
  • New energy

Published Papers (25 papers)

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Research

14 pages, 5450 KiB  
Article
Analytical Investigation on Torque of Three-Degree-of-Freedom Electromagnetic Actuator for Image Stabilization
by Chien-Sheng Liu, Yi-Hsuan Lin and Chiu-Nung Yeh
Appl. Sci. 2021, 11(15), 6872; https://doi.org/10.3390/app11156872 - 26 Jul 2021
Cited by 4 | Viewed by 2105
Abstract
In keeping with consumers’ preferences for electromagnetic motors of ever smaller power consumption, it is necessary to improve the power efficiency of the electromagnetic motors used in unmanned aerial vehicles and robots without sacrificing their performance. Three-degree-of-freedom (3-DOF) spherical motors have been developed [...] Read more.
In keeping with consumers’ preferences for electromagnetic motors of ever smaller power consumption, it is necessary to improve the power efficiency of the electromagnetic motors used in unmanned aerial vehicles and robots without sacrificing their performance. Three-degree-of-freedom (3-DOF) spherical motors have been developed for these applications. Accordingly, this study modifies the 3-DOF spherical motor proposed by Hirata’s group in a previous study (Heya, A.; Hirata, K.; Niguchi, N., Dynamic modeling and control of three-degree-of-freedom electromagnetic actuator for image stabilization, IEEE Transactions on Magnetics 2018, 54, 8207905.) to accomplish a 3-DOF spherical motor for camera module with higher torque output in the large rotation angle. The main contribution of this study is to improve the static torque in the X- and Y-axes with an improved electromagnetic structure and a particular controlling strategy. In the structural design, eight symmetrical coils with specific coil combination are used instead of conventional four symmetrical coils. In this study, the development of the proposed 3-DOF spherical motor was constructed and verified by using a 3D finite-element method (3D FEM). The simulation results show that the proposed 3-DOF spherical motor has higher torque output in the large rotation angle when compared to the original 3-DOF spherical motor. Full article
(This article belongs to the Special Issue Selected Papers from IMETI 2020)
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20 pages, 5099 KiB  
Article
A Co-Rotational Meshfree Method for the Geometrically Nonlinear Analysis of Structures
by Wen-Cheng Yeh
Appl. Sci. 2021, 11(14), 6647; https://doi.org/10.3390/app11146647 - 20 Jul 2021
Viewed by 1917
Abstract
This paper presents a co-rotational beam formulation, which is used for geometric nonlinear analysis with the differential reproducing kernel (DRK) approximation collocation method. The present formulation, based on the Timoshenko beam hypothesis, is capable of effectively solving geometrically nonlinear problems such as large [...] Read more.
This paper presents a co-rotational beam formulation, which is used for geometric nonlinear analysis with the differential reproducing kernel (DRK) approximation collocation method. The present formulation, based on the Timoshenko beam hypothesis, is capable of effectively solving geometrically nonlinear problems such as large deformation, postbuckling, lateral buckling, and snap-through problems. The kinematics have been constructed with the concept of co-rotational formulation adopted in the finite element method (FEM). A meshfree method based on the differential reproducing kernel (DRK) approximation collocation method, combined with the Newton–Raphson method, is employed to solve the strong forms of the geometrically nonlinear problems. The DRK method takes full advantage of the meshfree method. Moreover, only a scattered set of nodal points is necessary for the discretization. No elements or mesh connectivity data are required. Therefore, DRK will be able to completely circumvent the problems of mesh dependence and mesh distortion. The effectiveness of this study and its performance are shown through several numerical applications. Full article
(This article belongs to the Special Issue Selected Papers from IMETI 2020)
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17 pages, 5662 KiB  
Article
An Improved FFIP Method Based on Mathematical Logic and SysML
by Jian Jiao, Shujie Pang, Jiayun Chu, Yongfeng Jing and Tingdi Zhao
Appl. Sci. 2021, 11(8), 3534; https://doi.org/10.3390/app11083534 - 15 Apr 2021
Viewed by 1851
Abstract
In recent years, the model-based safety analysis (MBSA) has been developing continuously. The Functional Failure Identification and Propagation (FFIP) method is a graphics processing technology which supports the analysis of fault propagation paths before making costly design commitments. However, the traditional FFIP has [...] Read more.
In recent years, the model-based safety analysis (MBSA) has been developing continuously. The Functional Failure Identification and Propagation (FFIP) method is a graphics processing technology which supports the analysis of fault propagation paths before making costly design commitments. However, the traditional FFIP has some deficiencies. In this paper, we extend the functional failure logic (FFL) in the FFIP and introduce the concept of deviation. So, FFIP can be used to analyze the failure process of the systems and make the logical analysis of functional failure easier. Based on the extended FFL, we present a new overview of the FFIP. The FFIP is improved by using mathematical logic and Systems Modeling Language (SysML). The standard expression of FFL is realized, which is conducive to the subsequent modeling and modification. Additionally, we use the failure logic analysis in the FFIP to improve the state machine diagram (SMD) in SysML. Finally, the improved FFIP method is used to analyze the fault propagation paths of the system and Simulink is used for simulation. The fault tree is generated according to the simulation results, the minimum cut set is calculated, and the key failure parts of the system are obtained. Full article
(This article belongs to the Special Issue Selected Papers from IMETI 2020)
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12 pages, 3640 KiB  
Article
A Novel Accelerated Corrosion Test for Supporting Devices in a Floating Photovoltaic System
by Chun-Kuo Liu, Zhong-Ri Kong, Ming-Je Kao and Teng-Chun Wu
Appl. Sci. 2021, 11(8), 3308; https://doi.org/10.3390/app11083308 - 07 Apr 2021
Cited by 2 | Viewed by 2549
Abstract
Recently, countries from around the globe have been actively developing a new solar power system, namely, the floating photovoltaic (FPV) system. FPV is advantageous in terms of efficiency and cost effectiveness; however, environmental conditions on the surface of water are harsher than on [...] Read more.
Recently, countries from around the globe have been actively developing a new solar power system, namely, the floating photovoltaic (FPV) system. FPV is advantageous in terms of efficiency and cost effectiveness; however, environmental conditions on the surface of water are harsher than on the ground, and the regulations and standards for the long-term durability of supporting devices are insufficient. As a result, this study aims to investigate the durability of supporting devices through a novel type of accelerated corrosion test, copper-accelerated acetic acid salt spray (CASS). After an eight-day CASS test, the results demonstrated that only a small area of white protective layer on the SUPERDYMA shape steel was fully corroded and rusted. Moreover, five types of screw, fastened solidly on the SUPERDYMA shape steel, namely a galvanized steel screw capped with a type 316 stainless steel (SS) nut, a type 304 SS screw, a type 410 SS screw, a chromate-passivated galvanized steel screw, and a XP zinc–tin alloy coated steel screw, achieved varying degrees of rust. In general, the corrosion degree of the eight-day CASS test was more serious than that of the 136-day neutral salt spray (NSS) test. Therefore, the CASS test is faster and more efficient for the evaluation of the durability of supporting devices. Full article
(This article belongs to the Special Issue Selected Papers from IMETI 2020)
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11 pages, 1764 KiB  
Article
Analysis of Macroscopic Traffic Network Impacted by Structural Damage to Bridges from Earthquakes
by Joongmin Cho, Young-Joo Lee, Seongkwan Mark Lee, Ki Han Song and Wonho Suh
Appl. Sci. 2021, 11(7), 3226; https://doi.org/10.3390/app11073226 - 03 Apr 2021
Cited by 3 | Viewed by 1979
Abstract
Highway systems play a key role in providing mobility to society, especially during emergency situations, including earthquakes. Bridges in highway systems are susceptible to damage from earthquakes, causing traffic capacity loss leading to a serious impact on surrounding areas. To better prepare for [...] Read more.
Highway systems play a key role in providing mobility to society, especially during emergency situations, including earthquakes. Bridges in highway systems are susceptible to damage from earthquakes, causing traffic capacity loss leading to a serious impact on surrounding areas. To better prepare for such scenarios, it is important to estimate capacity loss and traffic disruptions from earthquakes. For this purpose, a traffic-capacity-analysisbased methodology was developed to model the performance of a transportation network immediately following an earthquake using a macroscopic multi-level urban traffic planning simulation model EMME4. This method employs the second order linear approximation (SOLA) traffic assignment and calculates total system travel time for various capacity loss scenarios due to bridge damage from earthquakes. It has been applied to Pohang City in Korea to evaluate the performance of traffic networks in various situations. The results indicate a significant increase in travel time and a decrease in travel speed as the intensity of an earthquake increases. However, the impact on traffic volume varies depending on the bridges. It is assumed that the location of the bridges and traffic routing patterns might be the main reason. The results are expected to help estimate the impact on transportation networks when earthquakes cause traffic capacity loss on bridges. Full article
(This article belongs to the Special Issue Selected Papers from IMETI 2020)
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15 pages, 7052 KiB  
Article
Highway Speed Prediction Using Gated Recurrent Unit Neural Networks
by Myeong-Hun Jeong, Tae-Young Lee, Seung-Bae Jeon and Minkyo Youm
Appl. Sci. 2021, 11(7), 3059; https://doi.org/10.3390/app11073059 - 29 Mar 2021
Cited by 23 | Viewed by 2918
Abstract
Movement analytics and mobility insights play a crucial role in urban planning and transportation management. The plethora of mobility data sources, such as GPS trajectories, poses new challenges and opportunities for understanding and predicting movement patterns. In this study, we predict highway speed [...] Read more.
Movement analytics and mobility insights play a crucial role in urban planning and transportation management. The plethora of mobility data sources, such as GPS trajectories, poses new challenges and opportunities for understanding and predicting movement patterns. In this study, we predict highway speed using a gated recurrent unit (GRU) neural network. Based on statistical models, previous approaches suffer from the inherited features of traffic data, such as nonlinear problems. The proposed method predicts highway speed based on the GRU method after training on digital tachograph data (DTG). The DTG data were recorded in one month, giving approximately 300 million records. These data included the velocity and locations of vehicles on the highway. Experimental results demonstrate that the GRU-based deep learning approach outperformed the state-of-the-art alternatives, the autoregressive integrated moving average model, and the long short-term neural network (LSTM) model, in terms of prediction accuracy. Further, the computational cost of the GRU model was lower than that of the LSTM. The proposed method can be applied to traffic prediction and intelligent transportation systems. Full article
(This article belongs to the Special Issue Selected Papers from IMETI 2020)
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29 pages, 2061 KiB  
Article
Global Study of Human Heart Rhythm Synchronization with the Earth’s Time Varying Magnetic Field
by Inga Timofejeva, Rollin McCraty, Mike Atkinson, Abdullah A. Alabdulgader, Alfonsas Vainoras, Mantas Landauskas, Vaiva Šiaučiūnaitė and Minvydas Ragulskis
Appl. Sci. 2021, 11(7), 2935; https://doi.org/10.3390/app11072935 - 25 Mar 2021
Cited by 13 | Viewed by 9525
Abstract
Changes in geomagnetic conditions have been shown to affect the rhythms produced by the brain and heart and that human autonomic nervous system activity reflected in heart rate variability (HRV) over longer time periods can synchronize to changes in the amplitude of resonant [...] Read more.
Changes in geomagnetic conditions have been shown to affect the rhythms produced by the brain and heart and that human autonomic nervous system activity reflected in heart rate variability (HRV) over longer time periods can synchronize to changes in the amplitude of resonant frequencies produced by geomagnetic field-line and Schumann resonances. During a 15-day period, 104 participants located in California, Lithuania, Saudi Arabia, New Zealand, and England underwent continuous ambulatory HRV monitoring. The local time varying magnetic field (LMF) intensity was obtained using a time synchronized and calibrated network of magnetometers located at five monitoring sites in the same geographical locations as the participant groups. This paper focuses on the results of an experiment conducted within the larger study where all of the participants simultaneously did a heart-focused meditation called a Heart Lock-In (HLI) for a 15-min period. The participant’s level of HRV coherence and HRV synchronization to each other before, during and after the HLI and the synchronization between participants’ HRV and local time varying magnetic field power during each 24-h period were computed for each participant and group with near-optimal chaotic attractor embedding techniques. In analysis of the participants HRV coherence before, during and after the HLI, most of the groups showed significantly increased coherence during the HLI period. The pairwise heart rhythm synchronization between participants’ in each group was assessed by determining the Euclidean distance of the optimal time lag vectors of each participant to all other participants in their group. The group member’s heart rhythms were significantly more synchronized with each other during the HLI period in all the groups. The participants’ daily LMF-HRV-synchronization was calculated for each day over an 11-day period, which provided a 5-day period before, the day of and 5-days after the HLI day. The only day where all the groups HRV was positively correlated with the LMF was on the day of the HLI and the synchronization between the HRV and LMF for all the groups was significantly higher than most of the other days. Full article
(This article belongs to the Special Issue Selected Papers from IMETI 2020)
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11 pages, 649 KiB  
Article
Global and Local Information Adjustment for Semantic Similarity Evaluation
by Tak-Sung Heo, Jong-Dae Kim, Chan-Young Park and Yu-Seop Kim
Appl. Sci. 2021, 11(5), 2161; https://doi.org/10.3390/app11052161 - 01 Mar 2021
Cited by 4 | Viewed by 1803
Abstract
Semantic similarity evaluation is used in various fields such as question-and-answering and plagiarism testing, and many studies have been conducted into this problem. In previous studies using neural networks to evaluate semantic similarity, similarity has been measured using global information of sentence pairs. [...] Read more.
Semantic similarity evaluation is used in various fields such as question-and-answering and plagiarism testing, and many studies have been conducted into this problem. In previous studies using neural networks to evaluate semantic similarity, similarity has been measured using global information of sentence pairs. However, since sentences do not only have one meaning but a variety of meanings, using only global information can have a negative effect on performance improvement. Therefore, in this study, we propose a model that uses global information and local information simultaneously to evaluate the semantic similarity of sentence pairs. The proposed model can adjust whether to focus more on global information or local information through a weight parameter. As a result of the experiment, the proposed model can show that the accuracy is higher than existing models that use only global information. Full article
(This article belongs to the Special Issue Selected Papers from IMETI 2020)
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16 pages, 5065 KiB  
Article
Using Recognizable Fuzzy Analysis for Non-Destructive Detection of Residual Stress in White Light Elements
by Han-Jui Chang, Zhong-Fa Mao, Zhi-Ming Su and Guang-Yi Zhang
Appl. Sci. 2021, 11(4), 1550; https://doi.org/10.3390/app11041550 - 08 Feb 2021
Cited by 6 | Viewed by 1640
Abstract
The phenomenon of residual stress in optical lens injection molding affects the quality of optical devices, with the refractive errors that are caused by geometric errors being the most serious, followed by the reduced accuracy and function of optical components; it is very [...] Read more.
The phenomenon of residual stress in optical lens injection molding affects the quality of optical devices, with the refractive errors that are caused by geometric errors being the most serious, followed by the reduced accuracy and function of optical components; it is very important to ensure that the lens geometry remains intact and that the refractive index is reduced. This paper uses a photoelastic stress compensation method for measurement verification along with fuzzy theory to reorganize a set of processes that can be used to evaluate the residual stress of a product, whereby the use of corresponding theoretical formulas can effectively quantify and measure the residual stress of the product. A mold flow simulation is used to analyze the molded optical components and determine the feasibility of evaluating the quality of the lens. Through the measurement of the refractive stress value of the optical components, the molding quality of the lens can be improved, and its force distribution effects can be investigated. Geometric analysis and shear stress affect the performance of optical components, and these errors may also cause irreparable problems during secondary processing. Therefore, it is crucial to reduce the residual stress of optical components. When the stress distribution is uniform and the internal melting pressure is reasonably configured, the product’s shrinkage rate can be controlled; the method for determining the residual stress is the core theme of this research. Full article
(This article belongs to the Special Issue Selected Papers from IMETI 2020)
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15 pages, 3332 KiB  
Article
Process Prediction for Compound Screws by Using Virtual Measurement and Recognizable Performance Evaluation
by Han-Jui Chang, Guang-Yi Zhang, Zhi-Ming Su and Zhong-Fa Mao
Appl. Sci. 2021, 11(4), 1549; https://doi.org/10.3390/app11041549 - 08 Feb 2021
Cited by 5 | Viewed by 1923
Abstract
One of the important values of Industry 4.0 is to integrate people’s needs into the manufacture of enhanced products, systems, and services to achieve greater levels of product customization. This paper presents a prediction method for predicting screw process parameters; taking crystalline and [...] Read more.
One of the important values of Industry 4.0 is to integrate people’s needs into the manufacture of enhanced products, systems, and services to achieve greater levels of product customization. This paper presents a prediction method for predicting screw process parameters; taking crystalline and non-crystalline polymers as the molding material, when there is a lack of sufficient historical screw process data to establish a data-driven method, using various screws and polymer materials to predict tool life under different cutting conditions is a challenge. A screw life prediction method is proposed based on the mixed compound screw process parameters method using a dynamic iteration work. To meet the requirements of mass production, this work proposes the combined application of the automatic virtual metrology (AVM) system with the recognizable performance evaluation (RPE) program. The method predicts the injection of compound screws by extracting given cutting conditions and related process parameters characteristics from the senor data by converting sampling inspections with measurement delays from real-time and online routine inspections to automatically and quickly complete method creation production goals. Full article
(This article belongs to the Special Issue Selected Papers from IMETI 2020)
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12 pages, 6344 KiB  
Article
Buckling of Rectangular Composite Pipes under Torsion
by Atsushi Takano, Ryo Mizukami and Ryuta Kitamura
Appl. Sci. 2021, 11(3), 1342; https://doi.org/10.3390/app11031342 - 02 Feb 2021
Cited by 3 | Viewed by 2468
Abstract
The numerical buckling load of rectangular composite pipes under torsional load was derived by using the energy method. The authors found no available simple design method or chart for the buckling loads of rectangular composite pipes, which are often used airplanes, spacecraft, and [...] Read more.
The numerical buckling load of rectangular composite pipes under torsional load was derived by using the energy method. The authors found no available simple design method or chart for the buckling loads of rectangular composite pipes, which are often used airplanes, spacecraft, and other lightweight structures, through their involvement in a Mars exploration airplane project. Thus, numerical results were obtained for length-to-width ratios (l/b) from 1 to 20, width-to-height ratios (h/b) from 1 to 6, and [0/90] layer ratios (r) from 0 to 1, which means [(0/90)r,(±45)1-r]s. The layups were assumed to be symmetric, and tension-bending, torsion-bending, and tension-shear coupling stiffnesses were ignored. To establish a simple design method, a closed-form polynomial equation for the buckling load factor was derived by minimizing the weighted residuals of the safe and non-safe side errors, which were obtained by comparing the derived numerical results with the polynomial equations. As a result, the errors of the polynomial equation for the buckling load factor were 4.95% for the non-safe side and 12.4% for the safe side. The errors are sufficiently good for preliminary design use and for parametric design studies and optimization. Full article
(This article belongs to the Special Issue Selected Papers from IMETI 2020)
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16 pages, 11123 KiB  
Article
Detecting Underground Geospatial Features for Protection of Rights in 3D Space: Korean Cases
by Sang Keun Bae and Jung Ok Kim
Appl. Sci. 2021, 11(3), 1102; https://doi.org/10.3390/app11031102 - 25 Jan 2021
Cited by 4 | Viewed by 1646
Abstract
Interest in underground space development is increasing owing to overcrowding in urban areas, and this trend is expected to continue in the future. Therefore, there exists a need to systematically establish and manage information on underground spaces. This information includes both the physical [...] Read more.
Interest in underground space development is increasing owing to overcrowding in urban areas, and this trend is expected to continue in the future. Therefore, there exists a need to systematically establish and manage information on underground spaces. This information includes both the physical status, that indicates the location or shape of the space, and the status of property rights related to the ownership and use of the space. In this study, a technique to register an entire underground shopping center space including individual store spaces along with the relationship with the above-ground parcels is proposed. The study considers the current management and operation system of the underground shopping center. 3D data were acquired from the Gwangbok Underground Shopping Center in Busan Metropolitan City, Korea using terrestrial LiDAR equipment. The VWorld data of the Korean Ministry of Land, Infrastructure, and Transport were also used as pre-built data. Furthermore, a spatial information-based management system was implemented. The data used comprise registration information for establishing property rights. These have the physical status and rights status information of the ground parcels as attribute information. Full article
(This article belongs to the Special Issue Selected Papers from IMETI 2020)
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11 pages, 4212 KiB  
Article
Effect of Lap Length and Stiffness of Peel-Stop Fasteners in Single Lap Joints
by Atsushi Takano, Chao Li and Ryuta Kitamura
Appl. Sci. 2021, 11(3), 1086; https://doi.org/10.3390/app11031086 - 25 Jan 2021
Viewed by 1613
Abstract
Strength tests on single lap joints with one adhesive (AV138/HV998) and one adhesive layer thickness (0.5 mm), three peel stoppers (brass bolt, nylon bolt and steel pin), and four lap lengths (12.5 mm, 25 mm, 40 mm and 100 mm) were conducted to [...] Read more.
Strength tests on single lap joints with one adhesive (AV138/HV998) and one adhesive layer thickness (0.5 mm), three peel stoppers (brass bolt, nylon bolt and steel pin), and four lap lengths (12.5 mm, 25 mm, 40 mm and 100 mm) were conducted to investigate the effects of varying the lap length and stiffness of the peel-stop fasteners. Joint failure stress decreased, but failure force increased with lap length. Furthermore, joint failure stress was higher with the peel stopper. The effect of the brass-bolt peel stoppers was significant, whereas the effects of the nylon bolts and steel pins were smaller than that of the brass bolts. This indicates that the axial clamp strength and stiffness of the peel stopper are important factors in the shear strength of the lap. In addition, the effect of the stopper was negligible for the 12.5 mm lap. The reason is that the shear strength in the case of the 12.5 mm lap was large and thus the effect of the peel stopper was comparatively small. Moreover, the strength of the 100 mm lap reached the adherent material’s strength. Full article
(This article belongs to the Special Issue Selected Papers from IMETI 2020)
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20 pages, 6366 KiB  
Article
The Energy-Aware Multi-UAV Dispatch and Handoff Algorithm for Maximizing the Event Communication Time in Disasters
by Ing-Chau Chang, Chi-Sheng Liao and Chin-En Yen
Appl. Sci. 2021, 11(3), 1054; https://doi.org/10.3390/app11031054 - 25 Jan 2021
Cited by 1 | Viewed by 1819
Abstract
For handling the broken-down communication infrastructure when a disaster event happens, this paper proposes to dispatch the unmanned aerial vehicle (UAV) to the disaster area as the relay node, which further forms a Flying Ad hoc Network (FANET). Since the UAV only owns [...] Read more.
For handling the broken-down communication infrastructure when a disaster event happens, this paper proposes to dispatch the unmanned aerial vehicle (UAV) to the disaster area as the relay node, which further forms a Flying Ad hoc Network (FANET). Since the UAV only owns limited energy and a disaster event may need multiple UAVs to cover its area, an efficient multi-UAV dispatch algorithm is critical to recover the communication link of the disaster area. In this paper, we adopt the mobile ground control station (GCS) to transport UAVs to the boundary of the disaster area first. According to the UAV energy consumption rate during flight and two communication modes, the UAV charging progress, and the number of required UAVs of the event, the mobile GCS then executes the proposed energy-aware multi-UAV dispatch algorithm (EAMUD) to dispatch multiple UAVs to this disaster area for building the FANET. Hence, the broken-down link in the disaster area is recovered after the FANET connects to nearby network infrastructure. Further, we propose the multi-UAV handoff scheme and exception handling processes to replace energy-exhausted UAVs for maximizing the event communication time of the disaster event. Finally, we execute simulations for related work and four EAMUD variants under different parameter values in the real scenario. These results exhibit that EAMUD with the Postpone method (EAMUD-P) achieves the highest event communication time among all these schemes. Full article
(This article belongs to the Special Issue Selected Papers from IMETI 2020)
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15 pages, 6406 KiB  
Article
Buckling Test of Composite Cylindrical Shells with Large Radius Thickness Ratio
by Atsushi Takano, Ryuta Kitamura, Takuma Masai and Jingxuan Bao
Appl. Sci. 2021, 11(2), 854; https://doi.org/10.3390/app11020854 - 18 Jan 2021
Cited by 3 | Viewed by 2209
Abstract
A buckling test of composite cylindrical shells with a radius–thickness ratio (r/t) = 893 under axial compression was conducted to investigate the effects of the radius–thickness ratio (r/t). It is known that the buckling load [...] Read more.
A buckling test of composite cylindrical shells with a radius–thickness ratio (r/t) = 893 under axial compression was conducted to investigate the effects of the radius–thickness ratio (r/t). It is known that the buckling load of cylinders shows large differences and scatter between theory and experiment. The ratio of the experimental buckling load and theoretical buckling load is called the knockdown factor (KDF). Many investigations have been conducted to find the cause of the degradation and scatter in the KDF, but as yet, no cause has been found. In 1968, NASA’s buckling design criterion, NASA SP-8007, gave an empirical KDF curve that decreased with the increasing r/t (up to 2000) for metal cylinders. The same curve has been applied to composite cylinders. Recently, Takano derived a flat lower-bound KDF in terms of A- and B-basis values (99% and 90% probability with a 95% confidence level) through a statistical analysis of experimental buckling loads. The result, however, based on experimental results up to r/t = 500 and, thus, the dependency on a large range of r/t, is not clear. Thus, the authors focused on a larger range of r/t. Cylindrical shells made from carbon fiber-reinforced plastic (CFRP) were tested. The nominal radius, thickness, and length were r = 100.118 mm, t = 0.118 mm, and L = 200 mm and, thus, the r/t = 848 and length-to-radius ratio (L/r) = 2.0. Shape imperfections were also measured by using in-house laser displacement equipment. The buckling load was slightly affected by the r/t, but the reduction in the KDF was insignificant. Full article
(This article belongs to the Special Issue Selected Papers from IMETI 2020)
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14 pages, 47401 KiB  
Article
Automated DNA Extraction Monitoring System Based on MTConnect Technology
by Sang-Ho Han, Ae-Ja Park, Ah-Reum Park and Mun-Ho Ryu
Appl. Sci. 2021, 11(2), 684; https://doi.org/10.3390/app11020684 - 12 Jan 2021
Cited by 2 | Viewed by 2137
Abstract
MTConnect standard technology provides simplicity, flexibility, and scalability in integrating various equipment and operating systems and enabling accurate and consistent data collection from any MTConnect-compatible system. Using MTConnect technology, it is possible to immediately identify the cause of a problem and respond quickly [...] Read more.
MTConnect standard technology provides simplicity, flexibility, and scalability in integrating various equipment and operating systems and enabling accurate and consistent data collection from any MTConnect-compatible system. Using MTConnect technology, it is possible to immediately identify the cause of a problem and respond quickly when a problem occurs. Molecular genetic diagnostic point-of-care testing (POCT) devices have received attention in recent years because they enable rapid disease diagnosis. A molecular genetic diagnostic POCT device is under development by the authors. The system consists of a gene extraction process and a real-time PCR-based gene amplification process. In this study, we propose and demonstrate a system based on MTConnect technology to monitor an automated DNA extraction process. The proposed system consists of an automated DNA extraction system, an MTConnect adapter, an MTConnect agent, and a client application. The adapter and agent were developed on a Raspberry Pi single-board computer. The agent publishes the collected data in Extensible Markup Language (XML) format over a network. The performance and reliability of the system were evaluated by verifying the request response time between the implemented system’s agent and the client application. The results demonstrate the feasibility of monitoring the DNA extraction process over a network. Full article
(This article belongs to the Special Issue Selected Papers from IMETI 2020)
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10 pages, 1780 KiB  
Article
Automatic Word Spacing of Korean Using Syllable and Morpheme
by Jeong-Myeong Choi, Jong-Dae Kim, Chan-Young Park and Yu-Seop Kim
Appl. Sci. 2021, 11(2), 626; https://doi.org/10.3390/app11020626 - 11 Jan 2021
Cited by 2 | Viewed by 2166
Abstract
In Korean, spacing is very important to understand the readability and context of sentences. In addition, in the case of natural language processing for Korean, if a sentence with an incorrect spacing is used, the structure of the sentence is changed, which affects [...] Read more.
In Korean, spacing is very important to understand the readability and context of sentences. In addition, in the case of natural language processing for Korean, if a sentence with an incorrect spacing is used, the structure of the sentence is changed, which affects performance. In the previous study, spacing errors were corrected using n-gram based statistical methods and morphological analyzers, and recently many studies using deep learning have been conducted. In this study, we try to solve the spacing error correction problem using both the syllable-level and morpheme-level. The proposed model uses a structure that combines the convolutional neural network layer that can learn syllable and morphological pattern information in sentences and the bidirectional long short-term memory layer that can learn forward and backward sequence information. When evaluating the performance of the proposed model, the accuracy was evaluated at the syllable-level, and also precision, recall, and f1 score were evaluated at the word-level. As a result of the experiment, it was confirmed that performance was improved from the previous study. Full article
(This article belongs to the Special Issue Selected Papers from IMETI 2020)
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12 pages, 6835 KiB  
Article
Design and Manufacture of Composite Landing Gear for a Light Unmanned Aerial Vehicle
by Yen-Chu Liang, Pei-Chieh Chin, Yun-Ping Sun and Muh-Rong Wang
Appl. Sci. 2021, 11(2), 509; https://doi.org/10.3390/app11020509 - 06 Jan 2021
Cited by 12 | Viewed by 7304
Abstract
Unmanned aerial vehicles (UAVs) have become popular for military applications as well as for use in structural inspection, weather monitoring, and festival demonstrations. Suitable landing gears to ensure that the UAV can take off and land safely are important when the price of [...] Read more.
Unmanned aerial vehicles (UAVs) have become popular for military applications as well as for use in structural inspection, weather monitoring, and festival demonstrations. Suitable landing gears to ensure that the UAV can take off and land safely are important when the price of the cargo and UAV increase. A lightweight and high-strength landing gear is desirable to overcome accidents during service. Composite materials are a promising, excellent solution for this purpose. This study demonstrated the design, numerical analysis (Ansys), manufacture, and experimental verification (LabVIEW) of a composite landing gear for a UAV. In particular, landing gears with different carbon fiber-reinforced polymer (CFRP) composite fiber orientations were analyzed, manufactured, and experimentally verified in this study. Full article
(This article belongs to the Special Issue Selected Papers from IMETI 2020)
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12 pages, 6133 KiB  
Article
High-Input Impedance Voltage-Mode Multifunction Filter
by San-Fu Wang, Hua-Pin Chen, Yitsen Ku and Yi-Fang Li
Appl. Sci. 2021, 11(1), 387; https://doi.org/10.3390/app11010387 - 03 Jan 2021
Cited by 11 | Viewed by 1833
Abstract
This paper proposes a high-input impedance voltage-mode (VM) multifunction biquad filter which employs three current-feedback amplifiers (CFAs), three resistors, and two grounded capacitors. The proposed VM multifunction biquad filter has single-input and triple-output and can realize non-inverting low-pass (NLP), inverting band-pass (IBP), and [...] Read more.
This paper proposes a high-input impedance voltage-mode (VM) multifunction biquad filter which employs three current-feedback amplifiers (CFAs), three resistors, and two grounded capacitors. The proposed VM multifunction biquad filter has single-input and triple-output and can realize non-inverting low-pass (NLP), inverting band-pass (IBP), and non-inverting band-stop (NBS) voltage responses at the same time without increasing component selection. The proposed VM multifunction biquad filter enjoys the orthogonal tunability of angular frequency and quality factor and also provides the advantage of using only two grounded capacitors, high-input impedance and low active/passive sensitivity. The performance of the proposed VM multifunction biquad filter is verified through its hardware implementation and OrCAD PSpice simulation based on AD844-type CFAs. The circuit analysis, sensitivity analysis, and NLP, IBP, and NBS voltage responses are also shown in this paper. The paper presents a method to effectively reduce the active and passive components, maintain good circuit performance, and reduce circuit costs. Full article
(This article belongs to the Special Issue Selected Papers from IMETI 2020)
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20 pages, 5537 KiB  
Article
Effect of Burner Operation on the Catalyst Tube Lifetime of a Steam Methane Reformer: A Numerical Study
by Chun-Lang Yeh
Appl. Sci. 2021, 11(1), 231; https://doi.org/10.3390/app11010231 - 29 Dec 2020
Cited by 4 | Viewed by 2831
Abstract
In this paper, the catalyst tube lifetime of a practical steam methane reformer is analyzed numerically. The effect of burner operating mode on the flow development, hydrogen yield, and catalyst tube lifetime is discussed, with the aim of improving the reformer performance. The [...] Read more.
In this paper, the catalyst tube lifetime of a practical steam methane reformer is analyzed numerically. The effect of burner operating mode on the flow development, hydrogen yield, and catalyst tube lifetime is discussed, with the aim of improving the reformer performance. The results of this study reveal that using the periodic boundary conditions, the temperatures and hydrogen yields obtained are much lower than the experimental values and the pressures are much lower than those using the real model. This results in overestimating the catalyst tube lifetime and underestimating the reformer operation risk. The catalyst tubes in the downstream area have longer lifetimes, while those in the upstream area have shorter lifetimes. Turning the upstream burners off is more efficient to the catalyst tube lifetime, while turning off the central groups of burners is less efficient. The main drawback of turning off burners is the decrease of hydrogen yield. Full article
(This article belongs to the Special Issue Selected Papers from IMETI 2020)
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15 pages, 2174 KiB  
Article
Graphical Analysis of Rollback Process in Ad Hoc Distributed Traffic Simulation
by Wonho Suh
Appl. Sci. 2021, 11(1), 121; https://doi.org/10.3390/app11010121 - 24 Dec 2020
Viewed by 1592
Abstract
Recent advancements in sensor, mobile computing, and wireless communication technologies is creating new opportunities to effectively exploit real-time traffic data. Onboard vehicles collect, process, simulate traffic states in a distributed fashion and a local transportation management center coordinates the overall simulation with an [...] Read more.
Recent advancements in sensor, mobile computing, and wireless communication technologies is creating new opportunities to effectively exploit real-time traffic data. Onboard vehicles collect, process, simulate traffic states in a distributed fashion and a local transportation management center coordinates the overall simulation with an optimistic execution technique. Such a distributed approach can provide more up-to-date and robust estimates with decreased communication bandwidth requirements and increased computing capacity. This paper proposes an online ad hoc distributed simulation. The physical operating platform for the model including operating system, communicational middleware, and traffic simulation model are described. Also, this paper investigates the analytical background of rollback process of the proposed ad hoc distributed simulation model. Flow rate diagram and cumulative number of vehicle diagram show that the overall system simulation speed and estimate accuracy may differ significantly as a function of the selected threshold. Full article
(This article belongs to the Special Issue Selected Papers from IMETI 2020)
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13 pages, 1860 KiB  
Article
Sign Language Recognition Using Two-Stream Convolutional Neural Networks with Wi-Fi Signals
by Chien-Cheng Lee and Zhongjian Gao
Appl. Sci. 2020, 10(24), 9005; https://doi.org/10.3390/app10249005 - 16 Dec 2020
Cited by 8 | Viewed by 2399
Abstract
Sign language is an important way for deaf people to understand and communicate with others. Many researchers use Wi-Fi signals to recognize hand and finger gestures in a non-invasive manner. However, Wi-Fi signals usually contain signal interference, background noise, and mixed multipath noise. [...] Read more.
Sign language is an important way for deaf people to understand and communicate with others. Many researchers use Wi-Fi signals to recognize hand and finger gestures in a non-invasive manner. However, Wi-Fi signals usually contain signal interference, background noise, and mixed multipath noise. In this study, Wi-Fi Channel State Information (CSI) is preprocessed by singular value decomposition (SVD) to obtain the essential signals. Sign language includes the positional relationship of gestures in space and the changes of actions over time. We propose a novel dual-output two-stream convolutional neural network. It not only combines the spatial-stream network and the motion-stream network, but also effectively alleviates the backpropagation problem of the two-stream convolutional neural network (CNN) and improves its recognition accuracy. After the two stream networks are fused, an attention mechanism is applied to select the important features learned by the two-stream networks. Our method has been validated by the public dataset SignFi and adopted five-fold cross-validation. Experimental results show that SVD preprocessing can improve the performance of our dual-output two-stream network. For home, lab, and lab + home environment, the average recognition accuracy rates are 99.13%, 96.79%, and 97.08%, respectively. Compared with other methods, our method has good performance and better generalization capability. Full article
(This article belongs to the Special Issue Selected Papers from IMETI 2020)
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12 pages, 4448 KiB  
Article
Power Line Interference Reduction Technique with a Current-Reused Current-Feedback Instrumentation Amplifier for ECG Recording
by Donggeun You, Hyunwoo Heo, Hyungseup Kim, Yongsu Kwon, Sangmin Lee and Hyoungho Ko
Appl. Sci. 2020, 10(23), 8478; https://doi.org/10.3390/app10238478 - 27 Nov 2020
Cited by 4 | Viewed by 3607
Abstract
This paper presents a power line interference (PLI) reduction technique with a current-reused current-feedback instrumentation amplifier (CFIA) for electrocardiogram (ECG) recording. In a portable two-electrode ECG monitoring application, the presence of undesired PLI may severely corrupt the quality of ECG recording. Since PLI [...] Read more.
This paper presents a power line interference (PLI) reduction technique with a current-reused current-feedback instrumentation amplifier (CFIA) for electrocardiogram (ECG) recording. In a portable two-electrode ECG monitoring application, the presence of undesired PLI may severely corrupt the quality of ECG recording. Since PLI can be over a few volts, the input signal including the ECG signal can exceed the supply or ground level by an electrostatic discharge (ESD) diode in input/output (I/O) pad. To prevent this problem, this paper presents a continuous-time input common-mode current feedback loop that can limit displacement current from a capacitive coupling between the human body and a power line. The continuous-time input common-mode current feedback loop can clamp an input common-mode voltage to the saturation region of the input transistor of the current-reused CFIA. After the clamping procedure, the clamped input signal is amplified by the current-reused CFIA. The proposed circuit was designed using a 0.18-μm bipolar-complementary metal semiconductor–double-diffused metal oxide semiconductor (BCDMOS) process with an active area of 1.8 mm2. The total power consumption is 18 μW with 1.8 V. The input-referred noise and noise efficiency factor (NEF) of the current-reused CFIA is 2.68 μVRMS and 4.28 with 107 Hz, respectively. Full article
(This article belongs to the Special Issue Selected Papers from IMETI 2020)
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9 pages, 56293 KiB  
Article
A 5.43 nV/√Hz Chopper Operational Amplifier Using Lateral PNP Input Stage with BJT Current Mirror Base Current Cancellation
by Hyungseup Kim, Yongsu Kwon, Donggeun You, Hyun-Woong Choi, Seong Hyun Kim, Hyunwoo Heo, Choul-Young Kim, Hi-Deok Lee and Hyoungho Ko
Appl. Sci. 2020, 10(23), 8376; https://doi.org/10.3390/app10238376 - 25 Nov 2020
Cited by 1 | Viewed by 2438
Abstract
This paper presents a low-noise chopper operational amplifier using a lateral PNP input stage with bipolar junction transistor (BJT) current mirror base current cancellation. The BJT has a lower noise characteristic than the metal–oxide–semiconductor (MOS) transistor, where low-noise characteristics can be achieved by [...] Read more.
This paper presents a low-noise chopper operational amplifier using a lateral PNP input stage with bipolar junction transistor (BJT) current mirror base current cancellation. The BJT has a lower noise characteristic than the metal–oxide–semiconductor (MOS) transistor, where low-noise characteristics can be achieved by implanting the BJT to the input stage of the amplifier; however, the base current of the BJT input stage causes low input impedance of the amplifier. The BJT current mirror base current cancellation technique is implemented to enhance the input impedance of the BJT input stage by canceling the base current. BJT current mirror base current cancellation is implemented with a simple scheme using NPN transistors with deep n-well in a generic complementary metal–oxide–semiconductor (CMOS) process. For further noise reduction with the BJT input stage, a chopper amplifier scheme is adopted to reduce low-frequency components such as 1/f noise terms in the low-frequency range. The prototype chip is fabricated in a 0.18-μm CMOS process. The active area of the prototype amplifier is 0.213 mm2. The measured input-referred noise is 5.43 nV/√Hz. The measured input base current of the amplifier with base current cancellation is 67.971 nA. The total amplifier current consumption is 278.3 μA, with a power supply of 3.3 V. Full article
(This article belongs to the Special Issue Selected Papers from IMETI 2020)
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20 pages, 9275 KiB  
Article
Multi-Temporal Land Cover Change Mapping Using Google Earth Engine and Ensemble Learning Methods
by Nimisha Wagle, Tri Dev Acharya, Venkatesh Kolluru, He Huang and Dong Ha Lee
Appl. Sci. 2020, 10(22), 8083; https://doi.org/10.3390/app10228083 - 15 Nov 2020
Cited by 36 | Viewed by 11444
Abstract
The study deals with the application of Google Earth Engine (GEE), Landsat data and ensemble-learning methods (ELMs) to map land cover (LC) change over a decade in the Kaski district of Nepal. As Nepal has experienced extensive changes due to natural and anthropogenic [...] Read more.
The study deals with the application of Google Earth Engine (GEE), Landsat data and ensemble-learning methods (ELMs) to map land cover (LC) change over a decade in the Kaski district of Nepal. As Nepal has experienced extensive changes due to natural and anthropogenic activities, monitoring such changes are crucial for understanding relationships and interactions between social and natural phenomena and to promote better decision-making. The main novelty lies in applying the XGBoost classifier for LC mapping over Nepal and monitoring the decadal changes of LC using ELMs. To map the LC change, a yearly cloud-free composite Landsat image was selected for the year 2010 and 2020. Combining the annual normalized difference vegetation index, normalized difference built-up index and modified normalized difference water index, with elevation and slope data from shuttle radar topography mission, supervised classification was performed using a random forest and extreme gradient boosting ELMs. Post classification change detection, validation and accuracy assessment were executed after the preparation of the LC maps. Three evaluation indices, namely overall accuracy (OA), Kappa coefficient, and F1 score from confusion matrix reports, were calculated for all the points used for validation purposes. We have obtained an OA of 0.8792 and 0.875 for RF and 0.8926 and 0.8603 for XGBoost at the 95% confidence level for 2010 and 2020 LC maps, which are better for mountainous terrain. The applied methodology could be significant in utilizing the big earth observation data and overcoming the traditional computational challenges using GEE. In addition, the quantification of changes over time would be helpful for decision-makers to understand current environmental dynamics in the study area. Full article
(This article belongs to the Special Issue Selected Papers from IMETI 2020)
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