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Appl. Sci., Volume 9, Issue 6 (March-2 2019)

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Cover Story (view full-size image) The aim of this study was to assess, through immunohistochemistry, the effects of an adapted [...] Read more.
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Open AccessArticle Adaptive Backstepping Sliding Mode Control Based RBFNN for a Hydraulic Manipulator Including Actuator Dynamics
Appl. Sci. 2019, 9(6), 1265; https://doi.org/10.3390/app9061265
Received: 4 February 2019 / Revised: 9 March 2019 / Accepted: 16 March 2019 / Published: 26 March 2019
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Abstract
In this paper, an adaptive robust control is investigated in order to deal with the unmatched and matched uncertainties in the manipulator dynamics and the actuator dynamics, respectively. Because these uncertainties usually include smooth and unsmooth functions, two adaptive mechanisms were investigated. First, [...] Read more.
In this paper, an adaptive robust control is investigated in order to deal with the unmatched and matched uncertainties in the manipulator dynamics and the actuator dynamics, respectively. Because these uncertainties usually include smooth and unsmooth functions, two adaptive mechanisms were investigated. First, an adaptive mechanism based on radial basis function neural network (RBFNN) was used to estimate the smooth functions. Based on the Taylor series expansion, adaptive laws derive for not only the weighting vector of the RBFNN, but also for the means and standard derivatives of the RBFs. The second one was the adaptive robust laws, which is designed to estimate the boundary of the unsmooth function. The robust gains will increase when the sliding variable leave the predefined region. Conversely, they will significantly decrease when the variable approaches the region. So, when these adaptive mechanisms are derived with the backstepping technique and sliding mode control, the proposed controller will compensate the uncertainties to improve the accuracy. In order to prove stability and robustness of the controlled system, the Lyapunov approach, based on backstepping technique, was used. Some simulation and experimental results of the proposed methodology in the electrohydraulic manipulator were presented and compared to other control to show the effectiveness of the proposed control. Full article
(This article belongs to the Section Mechanical Engineering)
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Open AccessArticle Experimental Study on a Prefabricated Lightweight Concrete-Filled Steel Tubular Framework Composite Slab Structure Subjected to Reversed Cyclic Loading
Appl. Sci. 2019, 9(6), 1264; https://doi.org/10.3390/app9061264
Received: 29 January 2019 / Revised: 19 March 2019 / Accepted: 19 March 2019 / Published: 26 March 2019
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Abstract
A building structure comprising a prefabricated lightweight concrete-filled steel tubular (CFST) framework composite slab structure is proposed. Five full-scale specimens (i.e., one empty framework and four-walled frameworks) were tested under reversed cyclic loading to study their earthquake-resistance performance. Of the four wall specimens, [...] Read more.
A building structure comprising a prefabricated lightweight concrete-filled steel tubular (CFST) framework composite slab structure is proposed. Five full-scale specimens (i.e., one empty framework and four-walled frameworks) were tested under reversed cyclic loading to study their earthquake-resistance performance. Of the four wall specimens, three were walled using composite slabs, one had no openings, one had a window opening, and one had a door opening. One was walled with a concealed steel-truss slab. A comparative study on the strength, stiffness, ductility, hysteresis characteristics, and dissipated energy of the specimens was performed. The working mechanism of the framework and slab was then analyzed. The results show that, if reasonably assembled and connected, the framework and slab work in a well-coordinated manner. The walled framework had greater lateral load-bearing capacity, better energy-dissipation, greater stiffness reduction, and better deformability than an empty framework. The area and type of slab opening had a significant impact on structural performance because a door or window opening contributed to a smaller lateral load-bearing capacity and initial secant stiffness of the structure. However, this had no clear impact on the accumulative dissipated energy of the structure. Full article
(This article belongs to the Section Civil Engineering)
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Open AccessArticle A Resource-Based View of Competitiveness in the Wind Energy Sector: The Case of Gran Canaria and Tenerife
Appl. Sci. 2019, 9(6), 1263; https://doi.org/10.3390/app9061263
Received: 19 February 2019 / Revised: 21 March 2019 / Accepted: 23 March 2019 / Published: 26 March 2019
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Abstract
This paper proposes a new model to assess the socio-economic potential of two outermost islands of the EU to exploit their resources and capabilities for the sustainable development of the wind energy sector. To that end, a territory competitiveness index is calculated from [...] Read more.
This paper proposes a new model to assess the socio-economic potential of two outermost islands of the EU to exploit their resources and capabilities for the sustainable development of the wind energy sector. To that end, a territory competitiveness index is calculated from the resource-based view to assess the socio-economic potential of renewable energy sources in Gran Canaria and Tenerife. We propose a model where local resources and capabilities in the wind energy industry are measured, taking into account different sources of information and methodologies, thus ensuring a rigorous process in the index calculation. In order to quantify the basic resources, for example, a methodology based on a multi-criteria analysis (MCA) with a geographic information system (GIS) is suggested, with the objective of obtaining an indicator called “index of available territorial resources." This index synthesizes the map information through a numerical value that allows integrating the territory resource with other indicators of the model, such as market growth, innovative behavior, firms’ concentration, or investment effort by the government. The results of the study show that capabilities development is a key factor to exploit the islands resource endowment in order to achieve a competitive advantage in wind energy. Full article
(This article belongs to the Special Issue State-of-the-Art and Applications of Renewable Energies in Europe)
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Open AccessFeature PaperReview Understanding Electronic Structure and Chemical Reactivity: Quantum-Information Perspective
Appl. Sci. 2019, 9(6), 1262; https://doi.org/10.3390/app9061262
Received: 18 February 2019 / Revised: 17 March 2019 / Accepted: 22 March 2019 / Published: 26 March 2019
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Abstract
Several applications of quantum mechanics and information theory to chemical reactivity problems are presented with emphasis on equivalence of variational principles for the constrained minima of the system electronic energy and its kinetic energy component, which also determines the overall gradient information. Continuities [...] Read more.
Several applications of quantum mechanics and information theory to chemical reactivity problems are presented with emphasis on equivalence of variational principles for the constrained minima of the system electronic energy and its kinetic energy component, which also determines the overall gradient information. Continuities of molecular probability and current distributions, reflecting the modulus and phase components of molecular wavefunctions, respectively, are summarized. Resultant measures of the entropy/information descriptors of electronic states, combining the classical (probability) and nonclassical (phase/current) contributions, are introduced, and information production in quantum states is shown to be of a nonclassical origin. Importance of resultant information descriptors for distinguishing the bonded (entangled) and nonbonded (disentangled) states of reactants in acid(A)–base(B) systems is stressed and generalized entropy concepts are used to determine the phase equilibria in molecular systems. The grand-canonical principles for the minima of electronic energy and overall gradient information allow one to explore relations between energetic and information criteria of chemical reactivity in open molecules. The populational derivatives of electronic energy and resultant gradient information give identical predictions of electronic flows between reactants. The role of electronic kinetic energy (resultant gradient information) in chemical-bond formation is examined, the virial theorem implications for the Hammond postulate of reactivity theory are explored, and changes of the overall structure information in chemical processes are addressed. The frontier-electron basis of the hard (soft) acids and bases (HSAB) principle is reexamined and covalent/ionic characters of the intra- and inter-reactant communications in donor-acceptor systems are explored. The complementary A–B coordination is compared with its regional HSAB analog, and polarizational/relaxational flows in such reactive systems are explored. Full article
(This article belongs to the Special Issue The Application of Quantum Mechanics in Reactivity of Molecules)
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Open AccessArticle Bacterial Foraging-Based Algorithm for Optimizing the Power Generation of an Isolated Microgrid
Appl. Sci. 2019, 9(6), 1261; https://doi.org/10.3390/app9061261
Received: 10 February 2019 / Revised: 17 March 2019 / Accepted: 18 March 2019 / Published: 26 March 2019
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Abstract
An Isolated Microgrid (IMG) is an electrical distribution network combined with modern information technologies aiming at reducing costs and pollution to the environment. In this article, we implement the Bacterial Foraging Optimization Algorithm (BFOA) to optimize an IMG model, which includes renewable energy [...] Read more.
An Isolated Microgrid (IMG) is an electrical distribution network combined with modern information technologies aiming at reducing costs and pollution to the environment. In this article, we implement the Bacterial Foraging Optimization Algorithm (BFOA) to optimize an IMG model, which includes renewable energy sources, such as wind and solar, as well as a conventional generation unit based on diesel fuel. Two novel versions of the BFOA were implemented and tested: Two-Swim Modified BFOA (TS-MBFOA), and Normalized TS-MBFOA (NTS-MBFOA). In a first experiment, the TS-MBFOA parameters were calibrated through a set of 87 independent runs. In a second experiment, 30 independent runs of both TS-MBFOA and NTS-MBFOA were conducted to compare their performance on minimizing the IMG using the best parameter tuning. Results showed that TS-MBFOA obtained better numerical solutions compared to NTS-MBFOA and LSHADE-CV, an Evolutionary Algorithm, found in the literature. However, the best solution found by NTS-MBFOA is better from a mechatronic point of view because it favors the lifetime of the IMG, resulting in economic savings in the long term. Full article
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Open AccessArticle Effects of Symbol Component on the Identifying of Graphic Symbols from EEG for Young Children with and without Developmental Delays
Appl. Sci. 2019, 9(6), 1260; https://doi.org/10.3390/app9061260
Received: 3 February 2019 / Revised: 12 March 2019 / Accepted: 21 March 2019 / Published: 26 March 2019
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Abstract
Using Augmentative and Alternative Communication (AAC) to improve the communication skills of children with disabilities is generally supported by both domestic and foreign scholars. Graphic symbols that represent individual words or phrases are often used in conjunction with AAC; however, research on the [...] Read more.
Using Augmentative and Alternative Communication (AAC) to improve the communication skills of children with disabilities is generally supported by both domestic and foreign scholars. Graphic symbols that represent individual words or phrases are often used in conjunction with AAC; however, research on the reading and identifying of AAC graphic symbols is scant. Therefore, this study used electroencephalogram (EEG) to investigate the success rates of identifying AAC graphic symbols and brainwave changes of young children with and without developmental delays. The results revealed that the number of symbol components affected participants’ success rates of identifying AAC graphic symbols. The EEG Attention Index between the children with and without developmental delays varied during the test. By contrast, the EEG Relaxation Index exhibited no difference between the children with and without developmental delays. When the participants viewed the single-component animations, the children without developmental delays had a significantly higher Relaxation Index than those with developmental delays did. According to cognitive load theory, the children with developmental delays and low cognitive capacities may feel stressed. Full article
(This article belongs to the Special Issue Signals in Health Care)
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Open AccessArticle Carbonation of Natural Wollastonite at Non-Ambient Conditions Relevant for CCS—the Possible Use as Cementitious Material in Wellbores
Appl. Sci. 2019, 9(6), 1259; https://doi.org/10.3390/app9061259
Received: 15 February 2019 / Revised: 5 March 2019 / Accepted: 21 March 2019 / Published: 26 March 2019
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Abstract
The reaction of wollastonite with CO2 accompanied by SO2 and NO2 in the presence of a chloride-rich brine (230 g/L NaCl, 15 g/L CaCl2, 5 g/L MgCl2) at temperatures relevant to injection conditions (333 K) in [...] Read more.
The reaction of wollastonite with CO2 accompanied by SO2 and NO2 in the presence of a chloride-rich brine (230 g/L NaCl, 15 g/L CaCl2, 5 g/L MgCl2) at temperatures relevant to injection conditions (333 K) in carbon capture and storage (CCS) were investigated within the joint BMWi (Federal Ministry for Economic Affairs and Energy) research project CLUSTER. The reaction which describes the formation of wollastonite during metamorphism is reversed and shows a strong temperature dependence. Wollastonite reacts in the presence of CO2 ( C ¯ ) in aqueous conditions to form calcium carbonate and amorphous silicon oxide. At 333 K and 2 MPa the carbonation reaction of wollastonite ( C ¯ C S ) is fast (<24 h). To determine the conversion rate of the reaction quantitatively different methods were used and compared: Powder X-ray diffraction (PXRD) with the Rietveld method and differential scanning calorimetry with thermogravimetry, coupled with a mass spectrometer (DSC-TG/MS) for quantitative phase analysis and for determination of the carbonation. The carbonation (CO2 accompanied by SO2 and NO2) of natural wollastonite at 333 K in presence of chloride-rich brine was rather fast (almost complete after 24 h reaction time). Full article
(This article belongs to the Section Chemistry)
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Open AccessArticle Chemical Defence of a Seagrass against Microfoulers and Its Seasonal Dynamics
Appl. Sci. 2019, 9(6), 1258; https://doi.org/10.3390/app9061258
Received: 6 March 2019 / Revised: 22 March 2019 / Accepted: 24 March 2019 / Published: 26 March 2019
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Abstract
In marine environments bacterial microfoulers are an important determinant for the settlement of algal and animal macrofoulers. At the same time fouling is usually subject to seasonal fluctuation. Additionally, the seagrass Zostera marina is prone to microfouling, although this marine spermatophyte is known [...] Read more.
In marine environments bacterial microfoulers are an important determinant for the settlement of algal and animal macrofoulers. At the same time fouling is usually subject to seasonal fluctuation. Additionally, the seagrass Zostera marina is prone to microfouling, although this marine spermatophyte is known to be chemically defended against bacterial settlers. Spermatophytes are often capable of induced or activated defences against biological enemies such as pathogens or herbivores, but it is still unknown whether they can fine-tune their antifouling-defence according to settlement pressure. We therefore assessed the seasonality of bacterial settlement pressure, defence against microsettlers and concentrations of a previously identified defence compound, rosmarinic acid, on surfaces of Z. marina. All examined variables peaked in summer, while they tended to be lower in spring and autumn. The seasonality of defence activity and rosmarinic acid surface concentration was positively correlated with the seasonal fluctuation of fouling pressure, which suggests that Z. marina can adjust its defence level to the relatively high bacterial fouling pressure in summer. Besides of biotic factors the seasonal change of environmental factors, such as nitrogen supply, and in particular temperature, also affected the defence level, either directly or through indirect effects on the microbial settlers. Full article
(This article belongs to the Special Issue Self-Cleaning and Antifouling Surfaces)
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Open AccessArticle Influence of CeO2 Addition to Ni–Cu/HZSM-5 Catalysts on Hydrodeoxygenation of Bio-Oil
Appl. Sci. 2019, 9(6), 1257; https://doi.org/10.3390/app9061257
Received: 25 February 2019 / Revised: 16 March 2019 / Accepted: 22 March 2019 / Published: 26 March 2019
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Abstract
Hydrodeoxygenation (HDO) of bio-oil is a method of bio-oil upgrading. In this paper, x%CeO2–Ni–Cu/HZSM-5 (x = 5, 15, and 20) was synthesized as an HDO catalyst by the co-impregnation method. The HDO performances of x%CeO2–Ni–Cu/HZSM-5 (x = 5, 15, [...] Read more.
Hydrodeoxygenation (HDO) of bio-oil is a method of bio-oil upgrading. In this paper, x%CeO2–Ni–Cu/HZSM-5 (x = 5, 15, and 20) was synthesized as an HDO catalyst by the co-impregnation method. The HDO performances of x%CeO2–Ni–Cu/HZSM-5 (x = 5, 15, and 20) in the reaction process was evaluated and compared with Ni–Cu/HZSM-5 by the property and the yield of upgrading oil. The difference of the chemical composition between bio-oil and upgrading oil was evaluated by GC-MS. The results showed that the addition of CeO2 decreased the water and oxygen contents of upgrading oil, increased the high heating value, reduced acid content, and increased hydrocarbon content. When the CeO2 addition was 15%, the yield of upgrading reached the maximum, from 33.9 wt% (Ni–Cu/HZSM-5) to 47.6 wt% (15%CeO2–Ni–Cu/HZSM-5). The catalytic activities of x%CeO2–Ni–Cu/HZSM-5 (x = 5, 15, and 20) and Ni–Cu/HZSM-5 were characterized by XRD, N2 adsorption–desorption, NH3-Temperature-Programmed Desorption, H2-Temperature-Programmed Reaction, TEM, and XPS. The results showed that the addition of CeO2 increased the dispersion of active metal Ni, reduced the bond between the active metal and the catalyst support, increased the ratio of Bronsted acid to total acids, and decreased the reduction temperature of NiO. When the CeO2 addition was 15%, the activity of catalyst reached the best. Finally, the carbon deposition resistance of deactivated catalysts was investigated by a Thermogravimetric (TG) analysis, and the results showed that the addition of CeO2 could improve the carbon deposition resistance of catalysts. When the CeO2 addition was 15%, the coke deposition decreased from 41 wt% (Ni–Cu/HZSM-5) to 14 wt% (15%CeO2–Ni–Cu/HZSM-5). Full article
(This article belongs to the Section Energy)
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Open AccessArticle Effect of Process Parameters on the Generated Surface Roughness of Down-Facing Surfaces in Selective Laser Melting
Appl. Sci. 2019, 9(6), 1256; https://doi.org/10.3390/app9061256
Received: 26 February 2019 / Revised: 18 March 2019 / Accepted: 20 March 2019 / Published: 26 March 2019
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Abstract
Additive manufacturing provides a number of benefits in terms of infinite freedom to design complex parts and reduced lead-times while globally reducing the size of supply chains as it brings all production processes under one roof. However, additive manufacturing (AM) lags far behind [...] Read more.
Additive manufacturing provides a number of benefits in terms of infinite freedom to design complex parts and reduced lead-times while globally reducing the size of supply chains as it brings all production processes under one roof. However, additive manufacturing (AM) lags far behind conventional manufacturing in terms of surface quality. This proves a hindrance for many companies considering investment in AM. The aim of this work is to investigate the effect of varying process parameters on the resultant roughness of the down-facing surfaces in selective laser melting (SLM). A systematic experimental study was carried out and the effects of the interaction of the different parameters and their effect on the surface roughness (Sa) were analyzed. It was found that the interaction and interdependency between parameters were of greatest significance to the obtainable surface roughness, though their effects vary greatly depending on the applied levels. This behavior was mainly attributed to the difference in energy absorbed by the powder. Predictive process models for optimization of process parameters for minimizing the obtained Sa in 45° and 35° down-facing surface, individually, were achieved with average error percentages of 5% and 6.3%, respectively, however further investigation is still warranted. Full article
(This article belongs to the Special Issue Micro/Nano Manufacturing)
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Open AccessArticle Numerical Study of a Proposed Semi-Submersible Floating Platform with Different Numbers of Offset Columns Based on the DeepCwind Prototype for Improving the Wave-Resistance Ability
Appl. Sci. 2019, 9(6), 1255; https://doi.org/10.3390/app9061255
Received: 29 January 2019 / Revised: 18 March 2019 / Accepted: 20 March 2019 / Published: 25 March 2019
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Abstract
DeepCwind semi-submersible floating offshore wind turbines have been widely examined, and in some countries this type of floating offshore wind turbine has been adopted in the construction of floating wind farms. However, the DeepCwind semi-submersible floating offshore wind turbines still experience large surge [...] Read more.
DeepCwind semi-submersible floating offshore wind turbines have been widely examined, and in some countries this type of floating offshore wind turbine has been adopted in the construction of floating wind farms. However, the DeepCwind semi-submersible floating offshore wind turbines still experience large surge motion that limits their operational time. Therefore, in this study, a semi-submersible floating platform with different numbers of offset columns, but with the same total weight, based on the DeepCwind prototype is proposed. From the free-decay test, it was found that the number of the floating columns will affect the natural frequency of the platform. Furthermore, the regular wave test in the time domain and the irregular wave test in the frequency domain show that increasing the number of the floating columns will reduce the surge motion greatly, while the effects in the heave and pitch motions are not obvious. Full article
(This article belongs to the Special Issue Offshore Wind Energy)
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Open AccessArticle Hybrid Grey Wolf Optimization Nonlinear Model Predictive Control for Aircraft Engines Based on an Elastic BP Neural Network
Appl. Sci. 2019, 9(6), 1254; https://doi.org/10.3390/app9061254
Received: 14 January 2019 / Revised: 12 March 2019 / Accepted: 21 March 2019 / Published: 25 March 2019
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Abstract
In order to deal with control constraints and the performance optimization requirements in aircraft engines, a new nonlinear model predictive control method based on an elastic BP neural network with a hybrid grey wolf optimizer is proposed in this paper. Based on the [...] Read more.
In order to deal with control constraints and the performance optimization requirements in aircraft engines, a new nonlinear model predictive control method based on an elastic BP neural network with a hybrid grey wolf optimizer is proposed in this paper. Based on the acquired aircraft engines data, the elastic BP neural network is used to train the prediction model, and the grey wolf optimization algorithm is applied to improve the selection of initial parameters in the elastic BP neural network. The accuracy of network modeling is increased as a result. By introducing the logistics chaotic sequence, the individual optimal search mechanism, and the cross operation, the novel hybrid grey wolf optimization algorithm is proposed and then used in receding horizon optimization to ensure real-time operation. Subsequently, a nonlinear model predictive controller for aircraft engine is obtained. Simulation results show that, with constraints in the control signal, the proposed nonlinear model predictive controller can guarantee that the aircraft engine has a satisfactory performance. Full article
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Open AccessArticle Validation of a Numerical Bending Model for Sandwich Beams with Textile-Reinforced Cement Faces by Means of Digital Image Correlation
Appl. Sci. 2019, 9(6), 1253; https://doi.org/10.3390/app9061253
Received: 31 January 2019 / Revised: 11 March 2019 / Accepted: 19 March 2019 / Published: 25 March 2019
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Abstract
Sandwich panels with textile-reinforced cement (TRC) faces merge both structural and insulating performance into one lightweight construction element. To design with sandwich panels, predictive numerical models need to be thoroughly validated, in order to use them with high confidence and reliability. Numerical bending [...] Read more.
Sandwich panels with textile-reinforced cement (TRC) faces merge both structural and insulating performance into one lightweight construction element. To design with sandwich panels, predictive numerical models need to be thoroughly validated, in order to use them with high confidence and reliability. Numerical bending models established in literature have been validated by means of local displacement measurements, but are missing a full surface strain validation. Therefore, four-point bending tests monitored by a digital image correlation system were compared with a numerical bending model, leading to a thorough validation of that numerical model. Monitoring with a digital image correlation (DIC) system gave a highly detailed image of behaviour during bending and the strains in the different materials of the sandwich panel. The measured strains validated the numerical model predictions of, amongst others, the multiple cracking of the TRC tensile face and the shear deformation of the core. Full article
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Open AccessArticle Coin Recognition Approach in Social Environments Using Virtual Organizations of Agents
Appl. Sci. 2019, 9(6), 1252; https://doi.org/10.3390/app9061252
Received: 1 February 2019 / Revised: 14 March 2019 / Accepted: 15 March 2019 / Published: 25 March 2019
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Abstract
Social systems have gained relevance during the last decade, trying to provide intelligent environments where humans and machines collaborate to resolve a social problem. The main objective of this paper is to obtain an intelligent system specifically designed to help dependent and/or visually [...] Read more.
Social systems have gained relevance during the last decade, trying to provide intelligent environments where humans and machines collaborate to resolve a social problem. The main objective of this paper is to obtain an intelligent system specifically designed to help dependent and/or visually disabled people to count money more easily by using a mobile phone camera. The proposed system incorporates an image recognition system for classifying coins by using homography to transform images previously for classification tasks. The main difficulty in the appliance of these techniques relies on the fact that camera position and height are unknown. This process allows changing the perspective of the images in order to calculate different meaningful variables such as diameter and colour employed later to perform classification and counting tasks. The system uses the information of the variables as inputs for classification algorithms that allow us to identify the amount and type of coins. The system has been tested with euro coins. This paper presents the results obtained. Full article
(This article belongs to the Special Issue Multi-Agent Systems 2020)
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Open AccessArticle Power and Signal-to-Noise Ratio Optimization in Mesh-Based Hybrid Optical Network-on-Chip Using Semiconductor Optical Amplifiers
Appl. Sci. 2019, 9(6), 1251; https://doi.org/10.3390/app9061251
Received: 3 March 2019 / Revised: 21 March 2019 / Accepted: 22 March 2019 / Published: 25 March 2019
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Abstract
To address the performance bottleneck in metal-based interconnects, hybrid optical network-on-chip (HONoC) has emerged as a new alternative. However, as the size of the HONoC grows, insertion loss and crosstalk noise increase, leading to excessive laser source output power and performance degradation. Therefore, [...] Read more.
To address the performance bottleneck in metal-based interconnects, hybrid optical network-on-chip (HONoC) has emerged as a new alternative. However, as the size of the HONoC grows, insertion loss and crosstalk noise increase, leading to excessive laser source output power and performance degradation. Therefore, we propose a low-power scalable HONoC architecture by incorporating semiconductor optical amplifiers (SOAs). An SOA placement algorithm is developed considering insertion loss and crosstalk noise. Furthermore, we establish a worst-case crosstalk noise model of SOA-enabled HONoC and induce optimized SOA gains with respect to power consumption and performance, respectively. Extensive simulations for worst-case signal-to-noise ratio (SNR) and power consumption are conducted under various traffic patterns and different network sizes. Simulation results show that the proposed SOA-enabled HONoC architecture and the associated algorithm help sustain the performance as network size increases without additional laser source power. Full article
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Open AccessArticle Active Noise Control over Space: A Subspace Method for Performance Analysis
Appl. Sci. 2019, 9(6), 1250; https://doi.org/10.3390/app9061250
Received: 28 February 2019 / Revised: 20 March 2019 / Accepted: 20 March 2019 / Published: 25 March 2019
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Abstract
In this paper, we investigate the maximum active noise control performance over a three-dimensional (3-D) spatial space, for a given set of secondary sources in a particular environment. We first formulate the spatial active noise control (ANC) problem in a 3-D room. Then [...] Read more.
In this paper, we investigate the maximum active noise control performance over a three-dimensional (3-D) spatial space, for a given set of secondary sources in a particular environment. We first formulate the spatial active noise control (ANC) problem in a 3-D room. Then we discuss a wave-domain least squares method by matching the secondary noise field to the primary noise field in the wave domain. Furthermore, we extract the subspace from wave-domain coefficients of the secondary paths and propose a subspace method by matching the secondary noise field to the projection of primary noise field in the subspace. Simulation results demonstrate the effectiveness of the proposed algorithms by comparison between the wave-domain least squares method and the subspace method, more specifically the energy of the loudspeaker driving signals, noise reduction inside the region, and residual noise field outside the region. We also investigate the ANC performance under different loudspeaker configurations and noise source positions. Full article
(This article belongs to the Special Issue Active and Passive Noise Control)
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Open AccessArticle Gender Classification Using Sentiment Analysis and Deep Learning in a Health Web Forum
Appl. Sci. 2019, 9(6), 1249; https://doi.org/10.3390/app9061249
Received: 15 February 2019 / Revised: 11 March 2019 / Accepted: 19 March 2019 / Published: 25 March 2019
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Abstract
Sentiment analysis is the most common text classification tool that analyzes incoming messages and tells whether the underlying sentiment is positive, negative, or neutral. We can use this technique to understand people by gender, especially people who are suffering from a sensitive disease. [...] Read more.
Sentiment analysis is the most common text classification tool that analyzes incoming messages and tells whether the underlying sentiment is positive, negative, or neutral. We can use this technique to understand people by gender, especially people who are suffering from a sensitive disease. People use health-related web forums to easily access health information written by and for non-experts and also to get comfort from people who are in a similar situation. The government operates medical web forums to provide medical information, manage patients’ needs and feelings, and boost information-sharing among patients. If we can classify people’s emotional or information needs by gender, age, or location, it is possible to establish a detailed health policy specialized into patient segments. However, people with sensitive illness such as AIDS tend to hide their information. Especially, in the case of sexually transmitted AIDS, we can detect problems and needs according to gender. In this work, we present a gender detection model using sentiment analysis and machine learning including deep learning. Through the experiment, we found that sentiment features generate low accuracy. However, senti-words give better results with SVM. Overall, traditional machine learning algorithms have a high misclassification rate for the female category. The deep learning algorithm overcomes this drawback with over 90% accuracy. Full article
(This article belongs to the Special Issue Sentiment Analysis for Social Media)
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Open AccessArticle Land Subsidence Susceptibility Mapping Using Bayesian, Functional, and Meta-Ensemble Machine Learning Models
Appl. Sci. 2019, 9(6), 1248; https://doi.org/10.3390/app9061248
Received: 25 January 2019 / Revised: 21 March 2019 / Accepted: 22 March 2019 / Published: 25 March 2019
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Abstract
To effectively prevent land subsidence over abandoned coal mines, it is necessary to quantitatively identify vulnerable areas. In this study, we evaluated the performance of predictive Bayesian, functional, and meta-ensemble machine learning models in generating land subsidence susceptibility (LSS) maps. All models were [...] Read more.
To effectively prevent land subsidence over abandoned coal mines, it is necessary to quantitatively identify vulnerable areas. In this study, we evaluated the performance of predictive Bayesian, functional, and meta-ensemble machine learning models in generating land subsidence susceptibility (LSS) maps. All models were trained using half of a land subsidence inventory, and validated using the other half of the dataset. The model performance was evaluated by comparing the area under the receiver operating characteristic (ROC) curve of the resulting LSS map for each model. Among all models tested, the logit boost, which is a meta-ensemble machine leaning model, generated LSS maps with the highest accuracy (91.44%), i.e., higher than that of the other Bayesian and functional machine learning models, including the Bayes net (86.42%), naïve Bayes (85.39%), logistic (88.92%), and multilayer perceptron models (86.76%). The LSS maps produced in this study can be used to mitigate subsidence risk for people and important facilities within the study area, and as a foundation for further studies in other regions. Full article
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Open AccessArticle Fermentation Characteristics of Lactobacillus Plantarum and Pediococcus Species Isolated from Sweet Sorghum Silage and Their Application as Silage Inoculants
Appl. Sci. 2019, 9(6), 1247; https://doi.org/10.3390/app9061247
Received: 30 December 2018 / Revised: 10 February 2019 / Accepted: 11 February 2019 / Published: 25 March 2019
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Abstract
This study aims to evaluate the fermentation characteristics of Lactobacillus plantarum and Pediococcus spp isolated from sweet sorghum silage to enhance the fermentation quality of Napier grass and sweet sorghum silage. Based on molecular 16S ribosomal ribonucleic identification the isolated strains were phylogenetically [...] Read more.
This study aims to evaluate the fermentation characteristics of Lactobacillus plantarum and Pediococcus spp isolated from sweet sorghum silage to enhance the fermentation quality of Napier grass and sweet sorghum silage. Based on molecular 16S ribosomal ribonucleic identification the isolated strains were phylogenetically related to Lactobacillus plantarum (HY1), Pediococcus acidilactici (HY2) and Pediococcus claussenii (HY3). Strains HY1, HY2 and HY3 and commercial bacteria Lactobacillus plantarum, Ecosyl; (MTD\1( were ensiled with sweet sorghum and Napier grass and the non-inoculated grasses, have been arranged in a completely randomized experimental design in a 5 (inoculants) × 3 (ensiling periods). In both grasses, the fermentation characteristics chemical composition and microbial population were assessed at 5–30 and 90 days of ensiling. The results showed that the effect of addition inoculants significantly reduced (p < 0.05) the pH, ammonia-N, acetic acid and undesirable microbial population and increased (p < 0.05) lactic acid and lactic acid bacteria counting when compared to the control. The effect of ensiling days on silage quality through the increasing lactic acid, acetic acid, ammonia-N, propionic acid and butyric acid whereas decreasing pH and water-soluble carbohydrates and microbial counts. In both sweet sorghum and Napier silage treated with isolated strains showed the best results in silage quality. The HY3 belongs to Pediococcus claussenii was not extensively studied in silage but it has shown good fermentation quality which strongly recommended to apply as probiotic. Full article
(This article belongs to the Section Chemistry)
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Open AccessArticle Improved Safety Analysis Integration in a Systems Engineering Approach
Appl. Sci. 2019, 9(6), 1246; https://doi.org/10.3390/app9061246
Received: 31 January 2019 / Revised: 26 February 2019 / Accepted: 4 March 2019 / Published: 25 March 2019
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Abstract
The goal of the paper is the integration of safety analysis in a model-based systems engineering approach to ensure consistency between system design and safety artifacts. This integration permits the continuous improvement of the structure and behavior of the system. It also reduces [...] Read more.
The goal of the paper is the integration of safety analysis in a model-based systems engineering approach to ensure consistency between system design and safety artifacts. This integration permits the continuous improvement of the structure and behavior of the system. It also reduces system development time and prevents late detection of errors. To reach this purpose, the SafeSysE methodology is extended. In SafeSysE, a preliminary Failure Mode and Effects Analysis (FMEA) is automatically generated from a SysML model, and this FMEA is then completed by the safety expert but no further development was proposed. The contribution of this paper is to suggest recommendations based on the FMEA analysis in order to enhance the system design and make it comply with safety requirements. First, an updated system structure that may contain redundancy is proposed. Then, a redundancy profile is used to enrich the system model with redundancy information, which will allow the generation of a dynamic fault tree considering the system behavior. Finally, the generated dynamic fault tree should be analyzed in order to create a state machine diagram that describes the behavior of the system. The created state machine with an internal block diagram will help the system designers to better understand the system dysfunctions by simulating the system. The proposed methodology is applied to an Electro-Mechanical Actuator system which is used in the aeronautics domain. Full article
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Open AccessArticle Study on the Stabilization Mechanisms of Clayey Slope Surfaces Treated by Spraying with a New Soil Additive
Appl. Sci. 2019, 9(6), 1245; https://doi.org/10.3390/app9061245
Received: 17 February 2019 / Revised: 20 March 2019 / Accepted: 22 March 2019 / Published: 25 March 2019
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Abstract
The topsoil of a clayey slope is easily washed off by rain due to its loose structure. To protect the slope surface, in recent years, several types of non-traditional soil additives have been used by means of mixing with soil. In this work, [...] Read more.
The topsoil of a clayey slope is easily washed off by rain due to its loose structure. To protect the slope surface, in recent years, several types of non-traditional soil additives have been used by means of mixing with soil. In this work, a new organic polymer soil stabilizer, named aqua-dispersing-nano-binder (ADNB), was sprayed on the soil surface to stabilize the topsoil of a clayey slope. To understand the interaction between the polymer and soil particles during the infiltration process as well as the stabilization mechanism, infiltration tests, water stability tests and scanning electron microscopy (SEM) analyses were performed with different polymer contents. The infiltration tests showed that the infiltration rate of the polymer stabilizer in the soil was slower than that of water due to its characteristics of easy adhesion to soil particles, poor fluidity and large molecular volume. The maximum effective infiltration depth was achieved in the specimen treated with 2% ADNB, and the minimum was achieved in the specimen treated with 5% ADNB. The water stability of the soil increased with the content of the soil stabilizer in the soil aggregates with diameters of either 5–10 mm or 10–20 mm. The SEM analysis showed that the quantity of polymer decreased with infiltration depth; a polymer membrane was formed on the surface of the topsoil and chains were formed inside. The amelioration of the soil water stability may have been due to the bonding between soil particles and polymers generated after evaporation of water in the emulsion. The polymer stabilizer could be applied to improve the erosion resistance of the slope topsoil and reduce soil loss. Full article
(This article belongs to the Section Environmental and Sustainable Science and Technology)
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Open AccessArticle Experimental Validation of Aero-Hydro-Servo-Elastic Models of a Scaled Floating Offshore Wind Turbine
Appl. Sci. 2019, 9(6), 1244; https://doi.org/10.3390/app9061244
Received: 15 January 2019 / Revised: 18 March 2019 / Accepted: 18 March 2019 / Published: 25 March 2019
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Abstract
Floating offshore wind turbines are complex dynamical systems. The use of numerical models is an essential tool for the prediction of the fatigue life, ultimate loads and controller design. The simultaneous wind and wave loading on a non-stationary foundation with a flexible tower [...] Read more.
Floating offshore wind turbines are complex dynamical systems. The use of numerical models is an essential tool for the prediction of the fatigue life, ultimate loads and controller design. The simultaneous wind and wave loading on a non-stationary foundation with a flexible tower makes the development of numerical models difficult, the validation of these numerical models is a challenging task as the floating offshore wind turbine system is expensive and the testing of these may cause loss of the system. The validation of these numerical models is often made on scaled models of the floating offshore wind turbines, which are tested in scaled environmental conditions. In this study, an experimental validation of two numerical models for a floating offshore wind turbines will be conducted. The scaled model is a 1:35 Froude scaled 5 MW offshore wind turbine mounted on a tension-leg platform. The two numerical models are aero-hydro-servo-elastic models. The numerical models are a theoretical model developed in a MATLAB/Simulink environment by the authors, while the other model is developed in the turbine simulation tool FAST. A comparison between the numerical models and the experimental dynamics shows good agreement. Though some effects such as the periodic loading from rotor show a complexity, which is difficult to capture. Full article
(This article belongs to the Special Issue Offshore Wind Energy)
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Open AccessArticle Compensation of Frequency Drift in Frequency-Sweep Polarization-Modulation Ranging System
Appl. Sci. 2019, 9(6), 1243; https://doi.org/10.3390/app9061243
Received: 29 January 2019 / Revised: 5 March 2019 / Accepted: 20 March 2019 / Published: 25 March 2019
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Abstract
In frequency-sweep polarization-modulation ranging, distance is determined by the frequency of modulated waves and the corresponding wavelength multiple when emitted and returned waves are in phase. However, measurement of the frequency and the wavelength multiple is affected by thermally induced phase delay of [...] Read more.
In frequency-sweep polarization-modulation ranging, distance is determined by the frequency of modulated waves and the corresponding wavelength multiple when emitted and returned waves are in phase. However, measurement of the frequency and the wavelength multiple is affected by thermally induced phase delay of the polarized wave. In this article we systematically discuss the principle of the ranging method and analyze the influences of thermally induced phase delay. New approaches to measurement are proposed to eliminate the impact on frequency and the wavelength multiple. Theoretical analysis and experimental results proved the efficiency and applicability of the methods. Full article
(This article belongs to the Special Issue Precision Dimensional Measurements)
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Open AccessArticle Evaluation of Waste Express Bag as a Novel Bitumen Modifier
Appl. Sci. 2019, 9(6), 1242; https://doi.org/10.3390/app9061242
Received: 22 February 2019 / Revised: 15 March 2019 / Accepted: 20 March 2019 / Published: 25 March 2019
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Abstract
With the rapid development of China’s e-commerce and logistics industry, a large number of waste express bags (WEBs) have been produced, which are difficult to recycle. The existing methods of waste express bag disposal often cause severe environmental pollution. It was discovered in [...] Read more.
With the rapid development of China’s e-commerce and logistics industry, a large number of waste express bags (WEBs) have been produced, which are difficult to recycle. The existing methods of waste express bag disposal often cause severe environmental pollution. It was discovered in this paper that the use of WEBs to modify bitumen could be an environmentally friendly way to recycle WEBs. This study aimed to investigate the feasibility of using WEBs to modify bitumen and promote the performance of WEB-modified bitumen. In order to verify this assumption, a series of basic or rheological experiments were conducted on different dosages of WEB-modified bitumen. The test results and phenomenon showed that the WEBs could be used to modify the binder homogeneously by using a high-speed shearing machine. The basic experiments showed that the WEBs could decrease the penetration and ductility while increasing the softening point and the rotational viscosity. Additionally, the rheological experimental data indicated that the high temperature performance was improved while the low temperature performance stayed the same. The Fourier-transform infrared spectroscopy (FTIR) results demonstrated that modification of the WEB was a physical modification without chemical reaction and the main component of the modifier was polyethylene. The fluorescence microscope (FM) data revealed the micro-structures of different dosages of WEB-modified bitumen. In conclusion, WEB can be a feasible binder modifier. Full article
(This article belongs to the Section Civil Engineering)
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Open AccessArticle Effects of Hooked-End Steel Fiber Geometry and Volume Fraction on the Flexural Behavior of Concrete Pedestrian Decks
Appl. Sci. 2019, 9(6), 1241; https://doi.org/10.3390/app9061241
Received: 21 February 2019 / Revised: 14 March 2019 / Accepted: 18 March 2019 / Published: 25 March 2019
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Abstract
This study investigates the effects of hooked-end fiber geometry and volume fraction on the flexural behavior of concrete pedestrian decks. To achieve this, three different fiber geometries, i.e., three-dimensional (3D), four-dimensional (4D), and five-dimensional (5D), and volume fractions of 0.37%, 0.6%, and 1.0% [...] Read more.
This study investigates the effects of hooked-end fiber geometry and volume fraction on the flexural behavior of concrete pedestrian decks. To achieve this, three different fiber geometries, i.e., three-dimensional (3D), four-dimensional (4D), and five-dimensional (5D), and volume fractions of 0.37%, 0.6%, and 1.0% were considered. Test results indicate that a higher number of hook ends can more effectively enhance the flexural strength and flexural strength margin at all volume fractions than a lower number, so that the order of effectiveness of hooked-end fibers on the flexural strength parameters was as follows: 5D > 4D > 3D. To satisfy the ductility index of 0.39, the amounts of 3D, 4D, and 5D hooked steel fibers should be in the range of 0.98%‒1.10%. Moreover, at a fiber volume fraction of 1.0%, only multiple cracking behaviors were observed, and the numerical results indicated that the volume fraction should be equal to 1.0% to guarantee a deflection-hardening response of pedestrian decks, regardless of the hooked-end fiber geometry. Consequently, a 1.0% by volume of hooked-end steel fiber is recommended to replace the minimum longitudinal steel rebars and guarantee a ductile flexural behavior with multiple cracks for pedestrian decks made of high-strength concrete. Full article
(This article belongs to the Section Civil Engineering)
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Open AccessArticle Adaptive Sliding Mode Trajectory Tracking Control for Unmanned Surface Vehicle with Modeling Uncertainties and Input Saturation
Appl. Sci. 2019, 9(6), 1240; https://doi.org/10.3390/app9061240
Received: 23 January 2019 / Revised: 11 March 2019 / Accepted: 19 March 2019 / Published: 25 March 2019
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Abstract
In the presence of modeling uncertainties and input saturation, this paper proposes a practical adaptive sliding mode control scheme for an underactuated unmanned surface vehicle (USV) using neural network, auxiliary dynamic system, sliding mode control and backstepping technique. First, the radial basis function [...] Read more.
In the presence of modeling uncertainties and input saturation, this paper proposes a practical adaptive sliding mode control scheme for an underactuated unmanned surface vehicle (USV) using neural network, auxiliary dynamic system, sliding mode control and backstepping technique. First, the radial basis function neural network with minimum learning parameter method (MLP) is constructed to online approximate the uncertain system dynamics, which uses single parameter instead of all weights online learning, leading to a reduction in the computational burdens. Then a hyperbolic tangent function is adopted to reduce the chattering phenomenon due to the sliding mode surface. Meanwhile, the auxiliary dynamic system and the adaptive technology are employed to handle input saturation and unknown disturbances, respectively. In addition, a neural shunting model is introduced to eliminate the “explosion of complexity” problem caused by the backstepping method for virtual control derivation. The stability of the closed-loop system is guaranteed by the Lyapunov stability theory. Finally, simulations are provided to validate the effectiveness of the proposed control scheme. Full article
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Open AccessArticle Parts Semantic Segmentation Aware Representation Learning for Person Re-Identification
Appl. Sci. 2019, 9(6), 1239; https://doi.org/10.3390/app9061239
Received: 26 February 2019 / Revised: 15 March 2019 / Accepted: 22 March 2019 / Published: 25 March 2019
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Abstract
Person re-identification is a typical computer vision problem which aims at matching pedestrians across disjoint camera views. It is challenging due to the misalignment of body parts caused by pose variations, background clutter, detection errors, camera point of view variation, different accessories and [...] Read more.
Person re-identification is a typical computer vision problem which aims at matching pedestrians across disjoint camera views. It is challenging due to the misalignment of body parts caused by pose variations, background clutter, detection errors, camera point of view variation, different accessories and occlusion. In this paper, we propose a person re-identification network which fuses global and local features, to deal with part misalignment problem. The network is a four-branch convolutional neural network (CNN) which learns global person appearance and local features of three human body parts respectively. Local patches, including the head, torso and lower body, are segmented by using a U_Net semantic segmentation CNN architecture. All four feature maps are then concatenated and fused to represent a person image. We propose a DropParts method to solve the parts missing problem, with which the local features are weighed according to the number of parts found by semantic segmentation. Since three body parts are well aligned, the approach significantly improves person re-identification. Experiments on the standard benchmark datasets, such as Market1501, CUHK03 and DukeMTMC-reID datasets, show the effectiveness of our proposed pipeline. Full article
(This article belongs to the Special Issue Advances in Deep Learning)
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Open AccessArticle High Precision Indoor Visible Light Positioning Algorithm Based on Double LEDs Using CMOS Image Sensor
Appl. Sci. 2019, 9(6), 1238; https://doi.org/10.3390/app9061238
Received: 16 February 2019 / Revised: 15 March 2019 / Accepted: 18 March 2019 / Published: 25 March 2019
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Abstract
Visible Light Positioning (VLP) is widely recognized as a cost-effective solution for indoor positioning with increasing demand. However, the nonlinearity and highly complex relationship between three-dimensional world coordinate and two-dimensional image coordinate hinders the good performance of image-sensor-based VLP. Therefore, there is a [...] Read more.
Visible Light Positioning (VLP) is widely recognized as a cost-effective solution for indoor positioning with increasing demand. However, the nonlinearity and highly complex relationship between three-dimensional world coordinate and two-dimensional image coordinate hinders the good performance of image-sensor-based VLP. Therefore, there is a need to develop effective VLP algorithms to locate the positioning terminal using image sensor. Besides, due to the high computational cost of image processing, most existing VLP systems do not achieve satisfactory performance in terms of real-time ability and positioning accuracy, both of which are significant for the performance of indoor positioning system. In addition, the accurate identification of the ID information of each LED (LED-ID) is important for positioning, because if the LED-ID is not recognized well, the positioning can only be achieved in a particular positioning unit and cannot be applied to a large scene with many LEDs. Therefore, an effective image-sensor-based double-light positioning system is proposed in this paper to solve the above problems. We also set up relevant experiments to test the performance of the proposed system, which utilizes the rolling shutter mechanism of the Complementary Metal Oxide Semiconductor (CMOS) image sensor. Machine learning was used to identify the LED-ID for better results. Simulation results show that the proposed double-light positioning system could deliver satisfactory performance in terms of both the real-time ability and the accuracy of positioning. Moreover, the proposed double-light positioning algorithm has low complexity and takes the symmetry problem of angle into consideration, which has never been considered before. Experiments confirmed that the proposed double-light positioning system can provide an accuracy of 3.85 cm with an average computing time of 56.28 ms, making it a promising candidate for future indoor positioning applications. Full article
(This article belongs to the Section Electrical, Electronics and Communications Engineering)
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Open AccessArticle Waste Bricks Applied as Removal Agent of Basic Blue 41 from Aqueous Solutions: Base Treatment and Their Regeneration Efficiency
Appl. Sci. 2019, 9(6), 1237; https://doi.org/10.3390/app9061237
Received: 13 February 2019 / Revised: 13 March 2019 / Accepted: 21 March 2019 / Published: 24 March 2019
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Abstract
Waste brick materials were applied as removal materials of basic blue 41 (BB-41) from artificially contaminated water. They were characterized by different techniques prior their use. A series of removal tests were carried out at different conditions, such as a dosage effect, pH [...] Read more.
Waste brick materials were applied as removal materials of basic blue 41 (BB-41) from artificially contaminated water. They were characterized by different techniques prior their use. A series of removal tests were carried out at different conditions, such as a dosage effect, pH value, initial concentrations, and chemical treatment. The removal results indicated that the two untreated waste bricks had limited removal capacities of basic blue 41, ranging from 19 to 30 mg/g. However, these values were improved upon treatment with NaOH solution or by increasing the removal temperature. Waste brick collected from the Medina area (Med-WB) exhibited higher removal capacity compared to the one collected from the Jeddah area (Jed-WB), with a maximum removal capacity of 60 mg/g at 60 °C. The pH of the BB-41 solution also played an important factor, as it improved the removal amounts from 25 mg/g to 45 mg/g at initial concentration of 200 mg/L. The regenerative process was studied using oxidative reaction of the removed basic blue 41 with a solution of oxone and cobalt nitrate. The efficiency was maintained after 5 runs for Med-WB, with a slight variation of 25%, while it felt to 50% for Jed-WB material after three runs. These data indicate that the waste brick materials present as potential candidates for the dye removal and their origin has to be identified. Full article
(This article belongs to the Section Chemistry)
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Open AccessArticle Analysis of the Weights of Service Quality Indicators for Drone Filming and Photography by the Fuzzy Analytic Network Process
Appl. Sci. 2019, 9(6), 1236; https://doi.org/10.3390/app9061236
Received: 2 February 2019 / Revised: 12 March 2019 / Accepted: 20 March 2019 / Published: 24 March 2019
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Abstract
The service of drone filming and photography has been getting more and more popular. However, the service provider does not have enough information about service quality indicators and its weights. Analyzing the weights of service quality indicators by the Fuzzy Analytic Network Process [...] Read more.
The service of drone filming and photography has been getting more and more popular. However, the service provider does not have enough information about service quality indicators and its weights. Analyzing the weights of service quality indicators by the Fuzzy Analytic Network Process (FANP) combined with Similarity Aggregation Method (SAM) is an important research topic. Therefore, in order to solve this real life problem, based on the SERVQUAL scale, this research analyzes the weights and the rankings from a comprehensive consensus by FANP combined with geometric mean and SAM, and then compares the differences between them. The results reveal that both the comprehensive consensus of experts’ opinions deemed that the most important dimension and indicator are reliability and “Employees are professional and get adequate support to do their jobs well.” The 2nd to 4th indicators from a comprehensive consensus of experts’ opinions are the same but the order is different. They are: “Drone service team’s employees give custom personal attention,” “Drone service team has up-to-date equipment,” and “Drone service team provides service legally, safely, and reliably.” The findings of the research reveal the weights of dimensions and indicators and help us to keep good service quality of filming and photography by drone. Full article
(This article belongs to the Special Issue Applied Sciences Based on and Related to Computer and Control)
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