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Appl. Sci., Volume 9, Issue 10 (May-2 2019)

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Open AccessArticle
A Simultaneous Localization and Mapping (SLAM) Framework for 2.5D Map Building Based on Low-Cost LiDAR and Vision Fusion
Appl. Sci. 2019, 9(10), 2105; https://doi.org/10.3390/app9102105 (registering DOI)
Received: 8 March 2019 / Revised: 10 April 2019 / Accepted: 13 May 2019 / Published: 22 May 2019
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Abstract
The method of simultaneous localization and mapping (SLAM) using a light detection and ranging (LiDAR) sensor is commonly adopted for robot navigation. However, consumer robots are price sensitive and often have to use low-cost sensors. Due to the poor performance of a low-cost [...] Read more.
The method of simultaneous localization and mapping (SLAM) using a light detection and ranging (LiDAR) sensor is commonly adopted for robot navigation. However, consumer robots are price sensitive and often have to use low-cost sensors. Due to the poor performance of a low-cost LiDAR, error accumulates rapidly while SLAM, and it may cause a huge error for building a larger map. To cope with this problem, this paper proposes a new graph optimization-based SLAM framework through the combination of low-cost LiDAR sensor and vision sensor. In the SLAM framework, a new cost-function considering both scan and image data is proposed, and the Bag of Words (BoW) model with visual features is applied for loop close detection. A 2.5D map presenting both obstacles and vision features is also proposed, as well as a fast relocation method with the map. Experiments were taken on a service robot equipped with a 360° low-cost LiDAR and a front-view RGB-D camera in the real indoor scene. The results show that the proposed method has better performance than using LiDAR or camera only, while the relocation speed with our 2.5D map is much faster than with traditional grid map. Full article
(This article belongs to the Special Issue LiDAR and Time-of-flight Imaging)
Open AccessArticle
Non-Invasive Morphological Characterization of Rice Leaf Bulliform and Aerenchyma Cellular Regions Using Low Coherence Interferometry
Appl. Sci. 2019, 9(10), 2104; https://doi.org/10.3390/app9102104 (registering DOI)
Received: 23 March 2019 / Revised: 16 May 2019 / Accepted: 20 May 2019 / Published: 22 May 2019
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Abstract
Non-invasive investigation of rice leaf specimens to characterize the morphological formation and particular structural information that is beneficial for agricultural perspective was demonstrated using a low coherence interferometric method called swept source optical coherence tomography (SS-OCT). The acquired results non-invasively revealed morphological properties [...] Read more.
Non-invasive investigation of rice leaf specimens to characterize the morphological formation and particular structural information that is beneficial for agricultural perspective was demonstrated using a low coherence interferometric method called swept source optical coherence tomography (SS-OCT). The acquired results non-invasively revealed morphological properties of rice leaf, such as bulliform cells; aerenchyma, parenchyma, and collenchyma layer; and vascular bundle. Beside aforementioned morphologic characteristics, several leaf characteristics associated with cytological mechanisms of leaf rolling (leaf inclination) were examined for the pre-identification of inevitable necrosis and atrophy of leaf tissues by evaluating acute angle information, such as angular characteristics of the external bi-directional angles between the lower epidermis layer and lower mid-vein, and internal angle of lower mid-vein. To further assist the pre-identification, acquired cross-sections were employed to enumerate the small veins of each leaf specimen. Since mutants enlarge leaf angles due to increased cell division in the adaxial epidermis, healthy and abnormal leaf specimens were morphologically and quantitatively compared. Therefore, the results of the method can be used in agriculture, and SS-OCT shows potential as a rigorous investigation method for selecting mutant infected rice leaf specimens rapidly and non-destructively compared to destructive and time consuming gold-standard methods with a lack of precision. Full article
(This article belongs to the Special Issue Optical Methods for Tissue Diagnostics)
Open AccessArticle
Coordinated Dispatch of Integrated Energy Systems Considering the Differences of Multiple Functional Areas
Appl. Sci. 2019, 9(10), 2103; https://doi.org/10.3390/app9102103 (registering DOI)
Received: 11 April 2019 / Revised: 16 May 2019 / Accepted: 18 May 2019 / Published: 22 May 2019
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Abstract
A large amount of wind turbine power and photovoltaic power is abandoned in many areas with abundant renewable energy due to thermal-electric coupling, inadequate local consumption capacity, and limited capacity of transmission lines, etc. To solve the above problems, a coordinated dispatching method [...] Read more.
A large amount of wind turbine power and photovoltaic power is abandoned in many areas with abundant renewable energy due to thermal-electric coupling, inadequate local consumption capacity, and limited capacity of transmission lines, etc. To solve the above problems, a coordinated dispatching method for integrated energy systems is proposed in this paper. Firstly, the spatiotemporal characteristics of diversified loads in multiple functional areas are introduced, including the inertia and elasticity of heating/cooling loads, the spatiotemporal distribution of electric vehicles, and the optimum transmission distance of diversified loads, etc. Secondly, a coordinated dispatching model of integrated energy systems is proposed, which considers the differences of multiple functional areas and various forms of energy systems. Finally, an actual distribution system in Jianshan District, Haining, Zhejiang Province of China is investigated for demonstrating the effectiveness of the proposed model. The results illustrate that the proposed model could effectively improve the consumption rate of renewable energy and reduce the volatility of renewable energy by considering the coordination of electric vehicles, tie lines, and heating/cooling systems in multiple functional areas. Full article
(This article belongs to the Section Energy)
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Open AccessArticle
Fault Classification of Rotary Machinery Based on Smooth Local Subspace Projection Method and Permutation Entropy
Appl. Sci. 2019, 9(10), 2102; https://doi.org/10.3390/app9102102 (registering DOI)
Received: 24 March 2019 / Revised: 10 May 2019 / Accepted: 13 May 2019 / Published: 22 May 2019
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Abstract
Collected mechanical signals usually contain a number of noises, resulting in erroneous judgments of mechanical condition diagnosis. The mechanical signals, which are nonlinear or chaotic time series, have a high computational complexity and intrinsic broadband characteristic. This paper proposes a method of gear [...] Read more.
Collected mechanical signals usually contain a number of noises, resulting in erroneous judgments of mechanical condition diagnosis. The mechanical signals, which are nonlinear or chaotic time series, have a high computational complexity and intrinsic broadband characteristic. This paper proposes a method of gear and bearing fault classification, based on the local subspace projection noise reduction and PE. A novel nonlinear projection noise reduction method, smooth orthogonal decomposition (SOD), is proposed to denoise the vibration signals of various operation conditions. SOD can decompose the reconstructed multiple strands to identify smooth local subspace. In the process of projection from a high dimension to a low dimension, a new weight matrix is put forward to achieve a better denoising effect. Afterwards, permutation entropy (PE) is applied in the detection of time sequence randomness and dynamic mutation behavior, which can effectively detect and amplify the variation of vibration signals. Hence PE can characterize the working conditions of gear and bearing under different conditions. The experimental results illustrate the effectiveness and superiority of the proposed approach. The theoretical derivations, numerical simulations and experimental studies, all confirm that the proposed approach based on the smooth local subspace projection method and PE, is promising in the field of the fault classification of rotary machinery. Full article
(This article belongs to the Special Issue Structural Damage Detection and Health Monitoring)
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Open AccessArticle
Thermal Evaluation of Graphene Nanoplatelets Nanofluid in a Fast-Responding HP with the Potential Use in Solar Systems in Smart Cities
Appl. Sci. 2019, 9(10), 2101; https://doi.org/10.3390/app9102101 (registering DOI)
Received: 25 April 2019 / Revised: 10 May 2019 / Accepted: 16 May 2019 / Published: 22 May 2019
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Abstract
An experimental study was undertaken to assess the heat-transfer coefficient (HTC) of graphene nanoplatelets-pentane nanofluid inside a gravity-assisted heat pipe (HP). Influence of various parameters comprising heat flux, mass fraction of the nanoparticles, installation angle and filling ratio (FR) of the working fluid [...] Read more.
An experimental study was undertaken to assess the heat-transfer coefficient (HTC) of graphene nanoplatelets-pentane nanofluid inside a gravity-assisted heat pipe (HP). Influence of various parameters comprising heat flux, mass fraction of the nanoparticles, installation angle and filling ratio (FR) of the working fluid on the HTC of the HP was investigated. Results showed that the HTC of the HP was strongly improved due to the presence of the graphene nanoplatelets. Also, by enhancing the heat flux, the HTC of the HP was improved. Two trade-off behaviors were identified. The first trade-off belonged to the available space in the evaporator and the heat-transfer coefficient of the system. Another trade-off was identified between the installation angle and the residence time of the working fluid inside the condenser unit. The installation angle and the FR of the HP were identified in which the HTC of the HP was the highest. The value of installation angle and filling ratio were 65° and 0.55, respectively. Likewise, the highest HTC was obtained at the largest mass fraction of the graphene nanoplatelets which was at wt. % = 0.3. The improvement in the HTC of the HP was ascribed to the Brownian motion and thermophoresis effects of the graphene nanoplatelets. Full article
(This article belongs to the Special Issue Solar Energy Applications in Houses, Smart Cities and Microgrids)
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Open AccessFeature PaperArticle
Comparison of Intensity- and Polarization-based Contrast in Amyloid-beta Plaques as Observed by Optical Coherence Tomography
Appl. Sci. 2019, 9(10), 2100; https://doi.org/10.3390/app9102100 (registering DOI)
Received: 7 May 2019 / Revised: 17 May 2019 / Accepted: 18 May 2019 / Published: 22 May 2019
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Abstract
One key hallmark of Alzheimer’s disease (AD) is the accumulation of extracellular amyloid-beta protein in cortical regions of the brain. For a definitive diagnosis of AD, post-mortem histological analysis, including sectioning and staining of different brain regions, is required. Here, we present optical [...] Read more.
One key hallmark of Alzheimer’s disease (AD) is the accumulation of extracellular amyloid-beta protein in cortical regions of the brain. For a definitive diagnosis of AD, post-mortem histological analysis, including sectioning and staining of different brain regions, is required. Here, we present optical coherence tomography (OCT) as a tissue-preserving imaging modality for the visualization of amyloid-beta plaques and compare their contrast in intensity- and polarization-sensitive (PS) OCT. Human brain samples of eleven patients diagnosed with AD were imaged. Three-dimensional PS-OCT datasets were acquired and plaques were manually segmented in 500 intensity and retardation cross-sections per patient using the freely available ITK-SNAP software. The image contrast of plaques was quantified. Histological staining of tissue sections from the same specimens was performed to compare OCT findings against the gold standard. Furthermore, the distribution of plaques was evaluated for intensity-based OCT, PS-OCT and the corresponding histological amyloid-beta staining. Only 5% of plaques were visible in both intensity and retardation segmentations, suggesting that different types of plaques may be visualized by the two OCT contrast channels. Our results indicate that multicontrast OCT imaging might be a promising approach for a tissue-preserving visualization of amyloid-beta plaques in AD. Full article
(This article belongs to the Special Issue Optical Coherence Tomography and its Applications)
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Open AccessArticle
A Robot Learning Method with Physiological Interface for Teleoperation Systems
Appl. Sci. 2019, 9(10), 2099; https://doi.org/10.3390/app9102099 (registering DOI)
Received: 16 December 2018 / Revised: 24 April 2019 / Accepted: 10 May 2019 / Published: 22 May 2019
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Abstract
The human operator largely relies on the perception of remote environmental conditions to make timely and correct decisions in a prescribed task when the robot is teleoperated in a remote place. However, due to the unknown and dynamic working environments, the manipulator’s performance [...] Read more.
The human operator largely relies on the perception of remote environmental conditions to make timely and correct decisions in a prescribed task when the robot is teleoperated in a remote place. However, due to the unknown and dynamic working environments, the manipulator’s performance and efficiency of the human-robot interaction in the tasks may degrade significantly. In this study, a novel method of human-centric interaction, through a physiological interface was presented to capture the information details of the remote operation environments. Simultaneously, in order to relieve workload of the human operator and to improve efficiency of the teleoperation system, an updated regression method was proposed to build up a nonlinear model of demonstration for the prescribed task. Considering that the demonstration data were of various lengths, dynamic time warping algorithm was employed first to synchronize the data over time before proceeding with other steps. The novelty of this method lies in the fact that both the task-specific information and the muscle parameters from the human operator have been taken into account in a single task; therefore, a more natural and safer interaction between the human and the robot could be achieved. The feasibility of the proposed method was demonstrated by experimental results. Full article
(This article belongs to the Special Issue Human Friendly Robotics)
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Open AccessArticle
Merging Observed and Self-Reported Behaviour in Agent-Based Simulation: A Case Study on Photovoltaic Adoption
Appl. Sci. 2019, 9(10), 2098; https://doi.org/10.3390/app9102098 (registering DOI)
Received: 2 April 2019 / Revised: 7 May 2019 / Accepted: 15 May 2019 / Published: 22 May 2019
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Abstract
Designing and evaluating energy policies is a difficult challenge because the energy sector is a complex system that cannot be adequately understood without using models merging economic, social and individual perspectives. Appropriate models allow policy makers to assess the impact of policy measures, [...] Read more.
Designing and evaluating energy policies is a difficult challenge because the energy sector is a complex system that cannot be adequately understood without using models merging economic, social and individual perspectives. Appropriate models allow policy makers to assess the impact of policy measures, satisfy strategic objectives and develop sustainable policies. Often the implementation of a policy cannot be directly enforced by governments, but falls back to many stakeholders, such as private citizens and enterprises. We propose to integrate two basic cornerstones to devise realistic models: the self-reported behaviour, derived from surveys, and the observed behaviour, from historical data. The self-reported behaviour enables the identification of drivers and barriers pushing or limiting people in their decision making process, while the observed behaviour is used to tune these drivers/barriers in a model. We test our methodology on a case-study: the adoption of photovoltaic panels among private citizens in the Emilia–Romagna region, Italy. We propose an agent-based model devised using self-reported data and then empirically tuned using historical data. The results reveal that our model can predict with great accuracy the photovoltaic (PV) adoption rate and thus support the energy policy-making process. Full article
(This article belongs to the Special Issue Multi-Agent Systems 2019)
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Open AccessArticle
The Impact of Demand Response Programs on Reducing the Emissions and Cost of A Neighborhood Home Microgrid
Appl. Sci. 2019, 9(10), 2097; https://doi.org/10.3390/app9102097
Received: 25 February 2019 / Revised: 13 May 2019 / Accepted: 15 May 2019 / Published: 21 May 2019
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Abstract
The desire to increase energy efficiency and reliability of power grids, along with the need for reducing carbon emissions has led to increasing the utilization of Home Micro-grids (H-MGs). In this context, the issue of economic emission dispatch is worthy of consideration, with [...] Read more.
The desire to increase energy efficiency and reliability of power grids, along with the need for reducing carbon emissions has led to increasing the utilization of Home Micro-grids (H-MGs). In this context, the issue of economic emission dispatch is worthy of consideration, with a view to controlling generation costs and reducing environmental pollution. This paper presents a multi-objective energy management system, with a structure based on demand response (DR) and dynamic pricing (DP). The proposed energy management system (EMS), in addition to decreasing the market clearing price (MCP) and increasing producer profits, has focused on reducing the level of generation units emissions, as well as enhancing utilization of renewable energy units through the DR programs. As a consequence of the nonlinear and discrete nature of the H-MGs, metaheuristic algorithms are applied to find the best possible solution. Moreover, due to the presence of generation units, the Taguchi orthogonal array testing (TOAT) method has been utilized to investigate the uncertainty regarding generation units. In the problem being considered, each H-MG interacts with each other and can negotiate based on their own strategies (reduction of cost or pollution). The obtained results indicate the efficiency of the proposed algorithm, a decrease in emissions and an increase in the profit achieved by each H-MG, by 37% and 10%, respectively. Full article
(This article belongs to the Special Issue Sustainable Energy Systems: Optimization and Efficiency)
Open AccessArticle
Experimental Investigation on the Performance of Historical Squat Masonry Walls Strengthened by UHPC and Reinforced Polymer Mortar Layers
Appl. Sci. 2019, 9(10), 2096; https://doi.org/10.3390/app9102096
Received: 3 April 2019 / Revised: 17 April 2019 / Accepted: 24 April 2019 / Published: 21 May 2019
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Abstract
Strengthening historical brick masonry walls is important because these walls are major load-bearing members in many architectural heritages. However, historical brick masonry has low elastic modulus and low strength, historical masonry walls are prone to surface treatment or other structural intervention, and some [...] Read more.
Strengthening historical brick masonry walls is important because these walls are major load-bearing members in many architectural heritages. However, historical brick masonry has low elastic modulus and low strength, historical masonry walls are prone to surface treatment or other structural intervention, and some of the walls lack integrity. These characteristics make effective strengthening of historical masonry walls difficult. To address the issue, strengthening layers made up of ultra-high performance concrete (UHPC) are potentially useful. To investigate the strengthening effect of the UHPC layers, the authors constructed three squat walls using historical bricks and mortar collected from the rehabilitation site of a historical building, and strengthened two of the walls with a UHPC layer and a reinforced polymer mortar layer respectively. The three walls were broken down by horizontal cyclic force along with constant vertical compression, and then the unstrengthened one was strengthened in-situ by a UHPC layer and was tested again. The experimental results indicate that the UHPC layers significantly improved the in-plane shear resistance and cracking load of the squat walls, without decreasing the walls’ ultimate deformation. They effectively strengthened both moderately and severely damaged historical masonry walls, because the UHPC filled the existing damages and improved the integrity of the masonry substrate. In addition, the UHPC layers intervened the historical walls less than the reinforced polymer mortar layer. Therefore, the UHPC layers are efficient in strengthening historical squat masonry walls. Full article
(This article belongs to the Special Issue Damage Inspection of Composite Structures)
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Open AccessArticle
Engineering Optogenetic Control of Endogenous p53 Protein Levels
Appl. Sci. 2019, 9(10), 2095; https://doi.org/10.3390/app9102095
Received: 2 May 2019 / Revised: 17 May 2019 / Accepted: 20 May 2019 / Published: 21 May 2019
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Abstract
The transcription factor p53 is a stress sensor that turns specific sets of genes on to allow the cell to respond to the stress depending on its severity and type. p53 is classified as tumor suppressor because its function is to maintain genome [...] Read more.
The transcription factor p53 is a stress sensor that turns specific sets of genes on to allow the cell to respond to the stress depending on its severity and type. p53 is classified as tumor suppressor because its function is to maintain genome integrity promoting cell cycle arrest, apoptosis, or senescence to avoid proliferation of cells with damaged DNA. While in many human cancers the p53 gene is itself mutated, there are some in which the dysfunction of the p53 pathway is caused by the overexpression of negative regulators of p53, such as Mdm2, that keep it at low levels at all times. Here we develop an optogenetic approach to control endogenous p53 levels with blue light. Specifically, we control the nuclear localization of the Mmd2-binding PMI peptide using the light-inducible export system LEXY. In the dark, the PMI-LEXY fusion is nuclear and binds to Mdm2, consenting to p53 to accumulate and transcribe the target gene p21. Blue light exposure leads to the export of the PMI-LEXY fusion into the cytosol, thereby Mdm2 is able to degrade p53 as in the absence of the peptide. This approach may be useful to study the effect of localized p53 activation within a tissue or organ. Full article
(This article belongs to the Special Issue The Advances and Applications of Optogenetics)
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Open AccessArticle
Vibration Control of an Aero Pipeline System with Active Constraint Layer Damping Treatment
Appl. Sci. 2019, 9(10), 2094; https://doi.org/10.3390/app9102094
Received: 30 March 2019 / Revised: 11 May 2019 / Accepted: 17 May 2019 / Published: 21 May 2019
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Abstract
In this paper, vibration control of an aero pipeline system using active constrained layer damping treatment has been investigated in terms of the vibration and stress distribution. A three-dimensional finite element model of such a pipeline with active constrained layer damping (ACLD) patches [...] Read more.
In this paper, vibration control of an aero pipeline system using active constrained layer damping treatment has been investigated in terms of the vibration and stress distribution. A three-dimensional finite element model of such a pipeline with active constrained layer damping (ACLD) patches is developed. The transfer of the driving force under harmonic voltage is analyzed based on the finite element model. The vibration control of the pipeline with active constrained layer damping treatment under different voltages is computed to analyze the influence of control parameters and structural parameters on the control effect. An experiment platform is developed to validate the above relations. Results show that the performance of the active constrained layer damping treatment is affected by the elastic modulus and thickness of the viscoelastic layer, control voltage and structure size. The performance increases significantly with the rising of the control voltage and cover area of ACLD patches among these parameters. Full article
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Open AccessReview
Progress in the Utilization Efficiency Improvement of Hot Carriers in Plasmon-Mediated Heterostructure Photocatalysis
Appl. Sci. 2019, 9(10), 2093; https://doi.org/10.3390/app9102093
Received: 10 April 2019 / Revised: 10 May 2019 / Accepted: 14 May 2019 / Published: 21 May 2019
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Abstract
The effect of plasmon-induced hot carriers (HCs) enables the possibility of applying semiconductors with wide band gaps to visible light catalysis, which becomes an emerging research field in environmental protections. Continued efforts have been made for an efficient heterostructure photocatalytic process with controllable [...] Read more.
The effect of plasmon-induced hot carriers (HCs) enables the possibility of applying semiconductors with wide band gaps to visible light catalysis, which becomes an emerging research field in environmental protections. Continued efforts have been made for an efficient heterostructure photocatalytic process with controllable behaviors of HCs. Recently, it has been discovered that the improvement of the utilization of HCs by band engineering is a promising strategy for an enhanced catalytic process, and relevant works have emerged for such a purpose. In this review, we give an overview of the recent progress relating to optimized methods for designing efficient photocatalysts by considering the intrinsic essence of HCs. First, the basic mechanism of the heterostructure photocatalytic process is discussed, including the formation of the Schokkty barrier and the process of photocatalysis. Then, the latest studies for improving the utilization efficiency of HCs in two aspects, the generation and extraction of HCs, are introduced. Based on this, the applications of such heterostructure photocatalysts, such as water/air treatments and organic transformations, are briefly illustrated. Finally, we conclude by discussing the remaining bottlenecks and future directions in this field. Full article
(This article belongs to the Special Issue Gold Nanoparticles for Catalytic Applications)
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Open AccessArticle
Hyperspectral Reflectance Imaging Combined with Multivariate Analysis for Diagnosis of Sclerotinia Stem Rot on Arabidopsis Thaliana Leaves
Appl. Sci. 2019, 9(10), 2092; https://doi.org/10.3390/app9102092
Received: 28 February 2019 / Revised: 1 May 2019 / Accepted: 14 May 2019 / Published: 21 May 2019
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Abstract
Sclerotinia stem rot (SSR) is one of the most destructive diseases in the world caused by Sclerotinia sclerotiorum (S. sclerotiorum), resulting in significant yield loss. Early and high-throughput detection would be critical to prevent SSR from spreading. This study aimed to [...] Read more.
Sclerotinia stem rot (SSR) is one of the most destructive diseases in the world caused by Sclerotinia sclerotiorum (S. sclerotiorum), resulting in significant yield loss. Early and high-throughput detection would be critical to prevent SSR from spreading. This study aimed to propose a feasible method for SSR detection based on the hyperspectral imaging coupled with multivariate analysis. The performance of different detecting algorithms were compared by combining the extreme learning machine (ELM), K-nearest neighbor algorithm (KNN), linear discriminant analysis (LDA), naïve Bayes classifier (NB) and the support vector machine (SVM) with the random frog (RF), successive projection algorithm (SPA) and sequential forward selection (SFS). The similarity of selected optimal wavelengths by three different feature selection methods indicated a high correlation between selected wavelengths and SSR. Compared with KNN, LDA, NB, and SVM, three wavelengths (455, 671 and 747 nm) selected by SFS-CA combined with ELM could achieve relatively better results with the overall accuracy of 93.7% and the lowest false negative rate of 2.4%. These results demonstrated the potential of the presented method using hyperspectral reflectance imaging combined with multivariate analysis for SSR diagnosis. Full article
(This article belongs to the Special Issue Application of Hyperspectral Imaging for Nondestructive Measurement)
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Open AccessArticle
Effect of Height and Geometry of Stepped Spillway on Inception Point Location
Appl. Sci. 2019, 9(10), 2091; https://doi.org/10.3390/app9102091
Received: 28 April 2019 / Revised: 15 May 2019 / Accepted: 17 May 2019 / Published: 21 May 2019
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Abstract
Air entrainment in a stepped spillway is very important to protect the spillway from cavitation damage. The inception point is the location where air starts entering the non-aerated flow zone. The inception point location depends on different parameters, such as the discharge, step [...] Read more.
Air entrainment in a stepped spillway is very important to protect the spillway from cavitation damage. The inception point is the location where air starts entering the non-aerated flow zone. The inception point location depends on different parameters, such as the discharge, step height, and step shape. In this paper, various stepped spillways, including flat steps, pooled steps, and round steps with different step heights were numerically simulated using the volume of fluid and realizable k-ε models. The results indicate that the inception point location moves downwards with the increase of the discharge of the stepped spillways. The length of the non-aerated flow zone increases with the discharge. The inception point location moves downwards as the step height decreases and the step number increases at the same discharge. The inception point location of the round stepped spillway model is much closer to the spillway crest than that of the flat stepped spillway with the same number of steps. The inception point location of the pooled stepped spillway is closer to the spillway crest than that of the flat stepped spillway, but more downstream than that of the round stepped spillway. Full article
(This article belongs to the Section Energy)
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Open AccessArticle
Study on Fatigue Characteristics and Interlayer Design Method of Waterproof Cohesive Bridge Deck Layer
Appl. Sci. 2019, 9(10), 2090; https://doi.org/10.3390/app9102090
Received: 9 April 2019 / Revised: 10 May 2019 / Accepted: 13 May 2019 / Published: 21 May 2019
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Abstract
Shear fatigue damage to the waterproof cohesive layer has not received enough attention in bridge deck pavement design. Meanwhile, there is less theoretical basis for the design of a waterproof cohesive layer. In this study, direct shear and shear fatigue tests were used [...] Read more.
Shear fatigue damage to the waterproof cohesive layer has not received enough attention in bridge deck pavement design. Meanwhile, there is less theoretical basis for the design of a waterproof cohesive layer. In this study, direct shear and shear fatigue tests were used to compare the shear strength and fatigue performance of waterproof adhesive materials under different disposal schemes for a cement slab surface, bonding materials, and spreading schemes, and the recommended optimal dosage of waterproof adhesive material for the bridge deck is given. Based on the shear fatigue tests results of indoor waterproof adhesive materials, an equation for prediction fatigue at 15 °C was established and temperature correction was applied. Based on these results, we propose a waterproof cohesive layer design method for bridge deck pavement with interlayer shear damage as the design index. The life expectancy of the shear damage between the decks was calculated for a real bridge deck. These results provide scientific guidance for design of a waterproof cohesive layer in a bridge deck, which can effectively extend the service life of a bridge deck. Full article
(This article belongs to the Section Civil Engineering)
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Open AccessArticle
Underfloor Heating Using Ceramic Thermal Panels and Solar Thermal Panels in Public Buildings in the Mediterranean: Energy Savings and Healthy Indoor Environment
Appl. Sci. 2019, 9(10), 2089; https://doi.org/10.3390/app9102089
Received: 25 March 2019 / Revised: 29 April 2019 / Accepted: 13 May 2019 / Published: 21 May 2019
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Abstract
Radiant floor air conditioning systems based on capillary tube mats, in addition to offering high comfort standards, generate significant energy savings. They allow the use of renewable energies such as thermal solar panels and combine them with solar cooling systems based on lithium [...] Read more.
Radiant floor air conditioning systems based on capillary tube mats, in addition to offering high comfort standards, generate significant energy savings. They allow the use of renewable energies such as thermal solar panels and combine them with solar cooling systems based on lithium chloride or absorption systems with lithium bromide in summer, cooling water down to 15–16 °C through solar thermal panel energy collection. Thus, in addition to energy savings from the transport of low water flows, annual energy demand is also reduced. This research analyses the application of thermal ceramic panels (TCP)—containing polypropylene (PPR) tube capillary mats—to public buildings in the Spanish Mediterranean. A case study of the Museum of the University of Alicante (MUA) is presented. Water was distributed individually from a split system heat pump inside the building combined with a thermal solar panel system on the roof. The MUA’s annual energy demand was quantified using thermal simulation tools and was monitored during the entire one-year cycle. Simulations were conducted both for the radiant floor system and an all-air conventional convective system, as well as with solar thermal panel applications. The reduction in annual energy demand was 24.91% when TCP panels are used on the floor. This is a considerable value, but lower than others results obtained in Central Europe due to the higher values of humidity. When solar thermal panels are installed on the rooftop the energy savings can increase to 60.70%. Full article
(This article belongs to the Special Issue Smart Home and Energy Management Systems 2019)
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Open AccessArticle
Numerical Investigation on Ultimate Compressive Strength of Welded Stiffened Plates Built by Steel Grades of S235–S390
Appl. Sci. 2019, 9(10), 2088; https://doi.org/10.3390/app9102088
Received: 15 April 2019 / Revised: 6 May 2019 / Accepted: 10 May 2019 / Published: 21 May 2019
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Abstract
The welded stiffened plate is widely used in naval architecture and offshore engineering as a basic structural member. The aim of this study is to investigate the effect of welding residual stress and steel grade on the ultimate strength of stiffened plates under [...] Read more.
The welded stiffened plate is widely used in naval architecture and offshore engineering as a basic structural member. The aim of this study is to investigate the effect of welding residual stress and steel grade on the ultimate strength of stiffened plates under uniaxial compressive load by non-linear finite element analysis. Nineteen stiffened plates built with three types of stiffeners with various column slenderness ratios provided in the ISSC’2000 VI.2 benchmark calculations are employed in the present study. The commercial finite element code ABAQUS is applied to simulate the collapse behavior of the stiffened plates and verified against the benchmark calculations. Fabrication-related imperfections, such as initial deflections and residual stresses, are accounted for in the simulations. The ultimate strength of stiffened plates built in common shipbuilding steels, namely S235, S315, S355 and S390, are investigated by varying the yield strength of materials in the simulation. Analysis of the numerical results shows that the welding residual stress reduces the ultimate strength of stiffened plates, and increase in yield strength of the material can effectively improve the ultimate strength of common ship stiffened plates; and quantitative analyses of their influences have also been performed. Full article
(This article belongs to the Special Issue Welding of Steels)
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Open AccessArticle
Demonstration of an Ultraprecise Optical Bench for the Taiji Space Gravitational Wave Detection Pathfinder Mission
Appl. Sci. 2019, 9(10), 2087; https://doi.org/10.3390/app9102087
Received: 19 April 2019 / Revised: 13 May 2019 / Accepted: 16 May 2019 / Published: 21 May 2019
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Abstract
For the Taiji space gravitational wave detection and its pathfinder mission, ultraprecise technology for optical assembly must be adopted to satisfy the high measurement sensitivities required. In this paper, we construct and evaluate an optical bench to assess its precision in optical assembly [...] Read more.
For the Taiji space gravitational wave detection and its pathfinder mission, ultraprecise technology for optical assembly must be adopted to satisfy the high measurement sensitivities required. In this paper, we construct and evaluate an optical bench to assess its precision in optical assembly and bonding. We opted for hydroxide-catalysis bonding technology and designed a corresponding adjustment scheme to achieve an ultraprecise assembly for the optical bench. After alignment, the angular deviation between the interference beam and its ideal position in the global coordinate system is no more than 45 μrad, and positional deviation is less than 10 μm. The final experimental results indicate that the measurement precision of the evaluated board is 6 pm/√Hz, which meets the specifications required for the Taiji pathfinder. Full article
(This article belongs to the Special Issue High-speed Optical 3D Shape and Deformation Measurement)
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Open AccessArticle
Can Phosphorus from Recycled Fertilisers Replace Conventional Sources? An Agronomic Evaluation in Field-Scale Experiments on Temperate Luvisols
Appl. Sci. 2019, 9(10), 2086; https://doi.org/10.3390/app9102086
Received: 15 April 2019 / Revised: 15 May 2019 / Accepted: 16 May 2019 / Published: 21 May 2019
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Abstract
Facing phosphate rock scarcity, growing food requirements and pollution problems with phosphorus (P)-containing waste, re-using P as fertiliser is becoming a real need. Innovative fertilisers from sewage sludge ash, animal bones and blood, activated by phosphorus solubilising microorganisms (PSM), were tested in field [...] Read more.
Facing phosphate rock scarcity, growing food requirements and pollution problems with phosphorus (P)-containing waste, re-using P as fertiliser is becoming a real need. Innovative fertilisers from sewage sludge ash, animal bones and blood, activated by phosphorus solubilising microorganisms (PSM), were tested in field experiments with winter or spring wheat and compared with commercial fertilisers (superphosphate, phosphorite). Three levels of P doses were established (17.6, 26.4 and 35.2 kg/ha). This paper discusses the fertilisers’ impact on total soil P content and on the P content and P accumulation in wheat grain and straw, weeds and post-harvest residues. Recycled fertilisers maintained soil P stocks and supplied plants with P in the same way as traditional fertilisers, and ensured a comparable P pool in the post-harvest residues to traditional fertilisers. They also did not favour weeds during competitive crop-weed interactions. The PSM included in waste-fertilisers did not exert an evident effect on the soil P content or on the P content and P accumulation in plant biomass. The findings show the potential of recycled fertilisers to act as a substitute to fertilisers from primary sources. Further field research is needed to settle the question of the reasonability of PSM inclusion into fertilisers. Full article
(This article belongs to the Special Issue Techniques for Sustainable Processing of Natural Resources)
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Open AccessArticle
Evaluation of Calf Muscle Reflex Control in the ‘Ankle Strategy’ during Upright Standing Push-Recovery
Appl. Sci. 2019, 9(10), 2085; https://doi.org/10.3390/app9102085
Received: 28 February 2019 / Revised: 16 May 2019 / Accepted: 16 May 2019 / Published: 21 May 2019
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Abstract
Revealing human internal control mechanisms during environmental interaction remains paramount and helpful in solving issues related to human-robot interaction. Muscle reflexes, which can directly and rapidly modify the dynamic behavior of joints, are the fundamental control loops of the Central Nervous System. This [...] Read more.
Revealing human internal control mechanisms during environmental interaction remains paramount and helpful in solving issues related to human-robot interaction. Muscle reflexes, which can directly and rapidly modify the dynamic behavior of joints, are the fundamental control loops of the Central Nervous System. This study investigates the calf muscle reflex control in the “ankle strategy” for human push-recovery movement. A time-increasing searching method is proposed to evaluate the feasibility of the reflex model in terms of predicting real muscle activations. Constraints with physiological implications are imposed to find the appropriate reflex gains. The experimental results show that the reflex model fits over 90% of the forepart of muscle activation. With the increasing of time, the Variance Accounted For (VAF) values drop to below 80% and reflex gains lose the physiology meaning. By dividing the muscle activation into two parts, the reflex formula is still workable for the rest part, with different gains and lower VAF values. This result may indicate that reflex control could more likely dominate the forepart of the push-recovery motion and an analogous control mechanism is still feasible for the rest of the motion part, with different gains. The proposed method provides an alternative way to obtain the human internal control mechanism desired for human-robot interaction task. Full article
(This article belongs to the Special Issue Human Friendly Robotics)
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Open AccessArticle
Numerical Approach for Studying the Evolution of the Degrees of Coherence of Partially Coherent Beams Propagation through an ABCD Optical System
Appl. Sci. 2019, 9(10), 2084; https://doi.org/10.3390/app9102084
Received: 18 April 2019 / Revised: 14 May 2019 / Accepted: 18 May 2019 / Published: 21 May 2019
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Abstract
In this paper, we propose a numerical approach to simulate the degree of coherence (DOC) of a partially coherent beam (PCB) with a Schell-model correlator in any transverse plane during propagation. The approach is applicable for PCBs whose initial intensity distribution and DOC [...] Read more.
In this paper, we propose a numerical approach to simulate the degree of coherence (DOC) of a partially coherent beam (PCB) with a Schell-model correlator in any transverse plane during propagation. The approach is applicable for PCBs whose initial intensity distribution and DOC distribution are non-Gaussian functions, even for beams for which it is impossible to obtain an analytical expression for the cross-spectral density (CSD) function. Based on our approach, numerical examples for the distribution of the DOC of two types of PCBs are presented. One type is the partially coherent Hermite–Gaussian beam. The simulation results of the DOC agree well with those calculated from the analytical formula. The other type of PCB is the one for which it is impossible to obtain an analytical expression of CSD. The evolution of the DOC with the propagation distance and in the far field is studied in detail. Our numerical approach may find potential applications in optical encryption and information transfer. Full article
(This article belongs to the Special Issue Recent Advances in Statistical Optics and Plasmonics)
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Open AccessArticle
Novel Phenotypic Elements of Type IV Collagenopathy Revealed by the Drosophila Model
Appl. Sci. 2019, 9(10), 2083; https://doi.org/10.3390/app9102083
Received: 5 April 2019 / Revised: 7 May 2019 / Accepted: 13 May 2019 / Published: 21 May 2019
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Abstract
Type IV collagen is proposed to be a key molecule in the evolvement of multicellular animals by forming the architectural unit basement membrane, a specialized form of the extracellular matrix. Functions of the basement membrane include guiding organ regeneration, tissue repair, modulation of [...] Read more.
Type IV collagen is proposed to be a key molecule in the evolvement of multicellular animals by forming the architectural unit basement membrane, a specialized form of the extracellular matrix. Functions of the basement membrane include guiding organ regeneration, tissue repair, modulation of cell differentiation, apical–basal polarity identification, cell migration and adhesion, regulation of growth factor signaling gradients, maintenance of tissue architecture and compartmentalization. Type IV collagenopathy is a devastating systemic disease affecting the circulatory, renal and visual systems and the skeletal muscles. It is observed in patients carrying mutations in the COL4A1 gene, which codes for the ubiquitous basement membrane component. Col4a1 mouse mutants display the human symptoms of type IV collagenopathy. We chose the Drosophila melanogaster model as we recorded dominant, temperature-sensitive mutations in the cognate col4a1 gene of the fruit fly and demonstrated phenotypic elements which have not yet been explored in humans or in mouse models. In this paper we show a transition of the Z-discs, normally bordering each sarcomere, to the level of M-discs significantly penetrant in the mutants, uneven distribution of fused mitochondria in the Malpighian tubules of the excretory organ and a loss of sarcomere structure in the visceral muscles in the gut of mutants. Our observations demonstrate the systemic nature of the col4a1 mutations in the fruit fly. However, these traits are elements of the type IV collagen-associated pathology and may provide insights into approaches that can alleviate symptoms of the disease. Full article
(This article belongs to the Section Applied Biosciences and Bioengineering)
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Open AccessArticle
Experimental Study of the Behavior of Rectangular Excavations Supported by a Pipe Roof
Appl. Sci. 2019, 9(10), 2082; https://doi.org/10.3390/app9102082
Received: 4 April 2019 / Revised: 8 May 2019 / Accepted: 9 May 2019 / Published: 21 May 2019
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Abstract
This paper presents an experimental investigation of the role of pipe-roofs in the improvement of the stability of rectangular excavations constructed using pipe-roof technology. This technology is suitable for the construction of underground passages in crowded areas subjected to high requirements concerning soil [...] Read more.
This paper presents an experimental investigation of the role of pipe-roofs in the improvement of the stability of rectangular excavations constructed using pipe-roof technology. This technology is suitable for the construction of underground passages in crowded areas subjected to high requirements concerning soil settlement and stability during excavation construction. The design of a rectangular pipe-roof excavation required an understanding of the interaction between the soil, the pipe-roof and the excavation. This interaction is complex and plays an important role in the features of the pipe roof excavation. This paper presents a series of 1g physical experimental tests conducted in dry sand soil with an advanced monitoring system, which allows tracking of the soil settlement, the pipe deformation and the soil pressure. Analysis of these tests shows the effective role of the pipe-roof in reducing both the soil settlement and the soil pressure on the excavation. It also shows the influence of pipes on the deformation mechanism of the soil and its evolution from low deformation to the instability phase. Full article
(This article belongs to the Section Civil Engineering)
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Open AccessArticle
Quantum-Key-Distribution (QKD) Networks Enabled by Software-Defined Networks (SDN)
Appl. Sci. 2019, 9(10), 2081; https://doi.org/10.3390/app9102081
Received: 18 April 2019 / Revised: 14 May 2019 / Accepted: 15 May 2019 / Published: 21 May 2019
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Abstract
As an important support for quantum communication, quantum key distribution (QKD) networks have achieved a relatively mature level of development, and they face higher requirements for multi-user end-to-end networking capabilities. Thus, QKD networks need an effective management plane to control and coordinate with [...] Read more.
As an important support for quantum communication, quantum key distribution (QKD) networks have achieved a relatively mature level of development, and they face higher requirements for multi-user end-to-end networking capabilities. Thus, QKD networks need an effective management plane to control and coordinate with the QKD resources. As a promising technology, software defined networking (SDN) can separate the control and management of QKD networks from the actual forwarding of the quantum keys. This paper systematically introduces QKD networks enabled by SDN, by elaborating on its overall architecture, related interfaces, and protocols. Then, three-use cases are provided as important paradigms with their corresponding schemes and simulation performances. Full article
(This article belongs to the Special Issue Quantum Optics for Fundamental Quantum Mechanics)
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Open AccessArticle
Super-Resolution Lensless Imaging of Cells Using Brownian Motion
Appl. Sci. 2019, 9(10), 2080; https://doi.org/10.3390/app9102080
Received: 23 April 2019 / Revised: 15 May 2019 / Accepted: 17 May 2019 / Published: 21 May 2019
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Abstract
The lensless imaging technique, which integrates a microscope into a complementary metal oxide semiconductor (CMOS) digital image sensor, has become increasingly important for the miniaturization of biological microscope and cell detection equipment. However, limited by the pixel size of the CMOS image sensor [...] Read more.
The lensless imaging technique, which integrates a microscope into a complementary metal oxide semiconductor (CMOS) digital image sensor, has become increasingly important for the miniaturization of biological microscope and cell detection equipment. However, limited by the pixel size of the CMOS image sensor (CIS), the resolution of a cell image without optical amplification is low. This is also a key defect with the lensless imaging technique, which has been studied by a many scholars. In this manuscript, we propose a method to improve the resolution of the cell images using the Brownian motion of living cells in liquid. A two-step algorithm of motion estimation for image registration is proposed. Then, the raw holographic images are reconstructed using normalized convolution super-resolution algorithm. The result shows that the effect of the collected cell image under the lensless imaging system is close to the effect of a 10× objective lens. Full article
(This article belongs to the Special Issue Advanced Ultrafast Imaging)
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Open AccessArticle
Seismic Response of Steel Moment Frames (SMFs) Considering Simultaneous Excitations of Vertical and Horizontal Components, Including Fling-Step Ground Motions
Appl. Sci. 2019, 9(10), 2079; https://doi.org/10.3390/app9102079
Received: 16 March 2019 / Revised: 6 May 2019 / Accepted: 14 May 2019 / Published: 20 May 2019
Viewed by 174 | PDF Full-text (595 KB)
Abstract
Near-field (NF) earthquakes have drawn considerable attention from earthquake and structural engineers. In the field of earthquake engineering, numerous studies have identified the devastating nature of such earthquakes, and examined the characteristics related to the response of engineering structures to these types of [...] Read more.
Near-field (NF) earthquakes have drawn considerable attention from earthquake and structural engineers. In the field of earthquake engineering, numerous studies have identified the devastating nature of such earthquakes, and examined the characteristics related to the response of engineering structures to these types of earthquakes. Herein, special steel moment frames (SMFs) of three-, five-, and eight-story buildings have been examined via a nonlinear time history analysis in OpenSees software. The behavioral seismic differences of these frames have been evaluated in two states: (1) under the simultaneous excitation of the horizontal and vertical constituents of near-field earthquakes that have Fling-steps in their records; and (2) under simultaneous excitation of the horizontal and vertical constituents of far-field (FF) earthquakes. In addition, during modeling, the effects of panel zones have been considered. Considering that the simultaneous effects of the horizontal and vertical constituents of near-field earthquakes were subjected to a fling-step resulting in an increased inter-story drift ratio, the horizontal displacement of stories, an axial force of columns, created the moment in columns, base shearing of the structure, and velocity and acceleration of the stories. Full article
Open AccessReview
Artificial Intelligence in Intelligent Tutoring Robots: A Systematic Review and Design Guidelines
Appl. Sci. 2019, 9(10), 2078; https://doi.org/10.3390/app9102078
Received: 26 February 2019 / Revised: 9 May 2019 / Accepted: 15 May 2019 / Published: 20 May 2019
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Abstract
This study provides a systematic review of the recent advances in designing the intelligent tutoring robot (ITR) and summarizes the status quo of applying artificial intelligence (AI) techniques. We first analyze the environment of the ITR and propose a relationship model for describing [...] Read more.
This study provides a systematic review of the recent advances in designing the intelligent tutoring robot (ITR) and summarizes the status quo of applying artificial intelligence (AI) techniques. We first analyze the environment of the ITR and propose a relationship model for describing interactions of ITR with the students, the social milieu, and the curriculum. Then, we transform the relationship model into the perception-planning-action model to explore what AI techniques are suitable to be applied in the ITR. This article provides insights on promoting a human-robot teaching-learning process and AI-assisted educational techniques, which illustrates the design guidelines and future research perspectives in intelligent tutoring robots. Full article
(This article belongs to the Section Computing and Artificial Intelligence)
Open AccessArticle
Coupled Dual-Loop Optoelectronic Oscillator Based on Stimulated Brillouin Scattering
Appl. Sci. 2019, 9(10), 2077; https://doi.org/10.3390/app9102077
Received: 12 April 2019 / Revised: 14 May 2019 / Accepted: 16 May 2019 / Published: 20 May 2019
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Abstract
A tunable optoelectronic oscillator (TOEO) with coupled dual-loop (CDL) based on stimulated Brillouin scattering (SBS) is proposed. In our scheme, the CDL is constructed by cascading a dual-output Mach–Zehnder intensity modulator (DOMZM) and a single output Mach–Zehnder intensity modulator (MZM). One optical output [...] Read more.
A tunable optoelectronic oscillator (TOEO) with coupled dual-loop (CDL) based on stimulated Brillouin scattering (SBS) is proposed. In our scheme, the CDL is constructed by cascading a dual-output Mach–Zehnder intensity modulator (DOMZM) and a single output Mach–Zehnder intensity modulator (MZM). One optical output of the DOMZM is directly injected to the MZM, and the other optical output of the DOMZM is transformed into microwave signals to modulate the MZM. The narrow gain spectrum of SBS is used to select the oscillation frequency and realize frequency tunability. By joining the CDL, we can not only increase side mode suppression ratio (SMSR) and decrease phase noise, but also improve stability of the TOEO. Experimental results show that microwave signals from 2 GHz to 18 GHz with the SMSR as high as 60 dB and the phase noise as low as −95 dBc/Hz at 10 kHz frequency offset are achieved. Furthermore, the frequency drift is less than 0.3 ppm and the power drift is lower than 0.2 dB at 10 GHz within 30 min in lab condition. Full article
(This article belongs to the Section Optics and Lasers)
Open AccessArticle
Effect of Incorporating Waste Limestone Powder into Solid Waste Cemented Paste Backfill Material
Appl. Sci. 2019, 9(10), 2076; https://doi.org/10.3390/app9102076
Received: 19 April 2019 / Revised: 8 May 2019 / Accepted: 17 May 2019 / Published: 20 May 2019
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Abstract
To effectively reuse waste limestone powder, which is a major solid waste around mines, we replaced limestone powder back into a part of cement in solid waste cemented paste backfill (SWCPB) and studied the parameters of pore structures. To optimize the pore microstructure [...] Read more.
To effectively reuse waste limestone powder, which is a major solid waste around mines, we replaced limestone powder back into a part of cement in solid waste cemented paste backfill (SWCPB) and studied the parameters of pore structures. To optimize the pore microstructure characteristics of SWCPB in mines, two different components and grade tailings were selected. The samples were characterized by scanning electron microscopy (SEM) and nuclear magnetic resonance (NMR) to examine the pore properties and microstructure of SWCPB. The results showed that (1) at the later curing stage, with the optimization of pore characteristics and microstructure through the limestone powder admixture, the strength of SWCFB was guaranteed at a 20% replacement degree of cement. (2) Porosity, macropore proportion, and the average pore radius all negatively correlated with limestone powder content, which were reduced by 7.15%, 46.35%, and 16.37%, respectively. (3) Limestone powder as a crystal nucleus participated in the hydration reaction and was embedded into the product to enhance the strength. Full article
(This article belongs to the Special Issue Low Binder Concrete and Mortars)
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