Applied Sciences

19 pages, 3584 KiB

Open AccessArticle

Multi-Objective Motion Control Optimization for the Bridge Crane System

by Renxin Xiao, Zelin Wang, Ningyuan Guo, Yitao Wu, Jiangwei Shen and Zheng Chen

Appl. Sci. 2018, 8(3), 473; https://doi.org/10.3390/app8030473 - 20 Mar 2018

Cited by 8 | Viewed by 4806

A novel control algorithm combining the linear quadratic regulator (LQR) control and trajectory planning (TP) is proposed for the control of an underactuated crane system, targeting position adjustment and swing suppression. The TP is employed to control the swing angle within certain constraints, [...] Read more.

A novel control algorithm combining the linear quadratic regulator (LQR) control and trajectory planning (TP) is proposed for the control of an underactuated crane system, targeting position adjustment and swing suppression. The TP is employed to control the swing angle within certain constraints, and the LQR is applied to achieve anti-disturbance. In order to improve the accuracy of the position control, a differential-integral control loop is applied. The weighted LQR matrices representing priorities of the state variables for the bridge crane motion are searched by the multi-objective genetic algorithm (MOGA). The stability proof is provided in order to validate the effectiveness of the proposed algorithm. Numerous simulation and experimental validations justify the feasibility of the proposed method. Full article

► Show Figures

Figure 1

9 pages, 25106 KiB

Open AccessArticle

Dispersion Properties of an Elliptical Patch with Cross-Shaped Aperture for Synchronized Propagation of Transverse Magnetic and Electric Surface Waves

by Amagoia Tellechea, Iñigo Ederra, Ramón Gonzalo and Juan Carlos Iriarte

Appl. Sci. 2018, 8(3), 472; https://doi.org/10.3390/app8030472 - 19 Mar 2018

Cited by 1 | Viewed by 4575

Abstract

This paper presents a novel pixel geometry for the implementation of metasurfaces requiring synchronized phase propagation of transverse magnetic (TM) and transverse electric (TE) modes. The pixel is composed by an elliptical metallic patch with an asymmetric cross-shaped aperture in the center, printed [...] Read more.

This paper presents a novel pixel geometry for the implementation of metasurfaces requiring synchronized phase propagation of transverse magnetic (TM) and transverse electric (TE) modes. The pixel is composed by an elliptical metallic patch with an asymmetric cross-shaped aperture in the center, printed on a grounded slab. A practical implementation of a metasurface was carried out employing such a pixel geometry. Simulation results show similar frequency dispersion properties for both modes within the working frequency band, in agreement with the theoretical basis. Full article

(This article belongs to the Special Issue Metasurfaces: Physics and Applications)

► Show Figures

Figure 1

19 pages, 7061 KiB

Open AccessArticle

Prostate Clinical Outlook Visualization System for Patients and Clinicians Considering Cyberknife Treatment—A Personalized Approach

by Jihwan Park, Mi Jung Rho, Anatoly Dritschilo, In Young Choi and Seong K. Mun

Appl. Sci. 2018, 8(3), 471; https://doi.org/10.3390/app8030471 - 19 Mar 2018

Cited by 4 | Viewed by 4825

Abstract

Background: When a patient presents with localized prostate cancer, referral for radiation oncology consultation includes a discussion of likely outcomes of therapy. Among current radiation treatments for prostate cancers, hypo-fractionated stereotactic body radiation therapy (SBRT) has gained clinical acceptance based on efficacy, short [...] Read more.

Background: When a patient presents with localized prostate cancer, referral for radiation oncology consultation includes a discussion of likely outcomes of therapy. Among current radiation treatments for prostate cancers, hypo-fractionated stereotactic body radiation therapy (SBRT) has gained clinical acceptance based on efficacy, short duration of treatment, and the potential radiobiological advantages. The Prostate Clinical Outlook Visualization System (PCOVS) was developed to provide the patient and the clinician with a tool to visualize probable treatment outcomes using institutional, patient specific data for comparing results of treatment. Methods: We calculated the prostate cancer outcomes—for each prospective patient using the EPIC-26 quality of life parameters based on clinical outcomes data of 580 prostate cancer patients who were treated with SBRT. We applied Kaplan-Meier analysis using the ASTRO definition for biochemical recurrence (BCR) free survival and likely outcome and the PCOVS nomogram to calculate parameters for quality of life. Open-source R, RShiny, and MySQL were used to develop a modularized architecture system. Results: The PCOVS presents patient specific risk scores in a gauge chart style and risk free probability bar plots to compare the treatment data of patients treated with SBRT. The PCOVS generates reports, in PDF, which consists of a comparison charts of risk free probabilities late effects and gauge charts of risk scores. This system is now being expanded as a web-based service to patients. Conclusions: The PCOVS visualized patient specific likely outcomes were compared to treatment data from a single department, helping the patient and the clinician to visualize likely outcomes. The PCOVS approach can be expanded to other specialties of oncology with the flexible, modularized architecture, which can be customized by changing independent modules. Full article

► Show Figures

Figure 1

15 pages, 2277 KiB

Open AccessArticle

Polyphonic Piano Transcription with a Note-Based Music Language Model

by Qi Wang, Ruohua Zhou and Yonghong Yan

Appl. Sci. 2018, 8(3), 470; https://doi.org/10.3390/app8030470 - 19 Mar 2018

Cited by 10 | Viewed by 4838

Abstract

This paper proposes a note-based music language model (MLM) for improving note-level polyphonic piano transcription. The MLM is based on the recurrent structure, which could model the temporal correlations between notes in music sequences. To combine the outputs of the note-based MLM and [...] Read more.

This paper proposes a note-based music language model (MLM) for improving note-level polyphonic piano transcription. The MLM is based on the recurrent structure, which could model the temporal correlations between notes in music sequences. To combine the outputs of the note-based MLM and acoustic model directly, an integrated architecture is adopted in this paper. We also propose an inference algorithm, in which the note-based MLM is used to predict notes at the blank onsets in the thresholding transcription results. The experimental results show that the proposed inference algorithm improves the performance of note-level transcription. We also observe that the combination of the restricted Boltzmann machine (RBM) and recurrent structure outperforms a single recurrent neural network (RNN) or long short-term memory network (LSTM) in modeling the high-dimensional note sequences. Among all the MLMs, LSTM-RBM helps the system yield the best results on all evaluation metrics regardless of the performance of acoustic models. Full article

(This article belongs to the Special Issue Digital Audio and Image Processing with Focus on Music Research)

► Show Figures

Figure 1

14 pages, 6482 KiB

Open AccessArticle

Evaluation of Fatigue Life of Asphalt Concrete Mixtures with Reclaimed Asphalt Pavement

by Wojciech Bańkowski

Appl. Sci. 2018, 8(3), 469; https://doi.org/10.3390/app8030469 - 19 Mar 2018

Cited by 39 | Viewed by 6297

Abstract

The topic of this article is the evaluation of the fatigue life of asphalt concrete mixtures with reclaimed asphalt pavement (RAP). The evaluation was carried out in relation to asphalt concrete mixtures AC22P and high modulus asphalt concrete ACWMS16 with 50% contents of [...] Read more.

The topic of this article is the evaluation of the fatigue life of asphalt concrete mixtures with reclaimed asphalt pavement (RAP). The evaluation was carried out in relation to asphalt concrete mixtures AC22P and high modulus asphalt concrete ACWMS16 with 50% contents of RAP, greater than currently permitted by technical regulations in Poland. The first stage consisted of the evaluation of laboratory results, which was followed by a mechanistic analysis of the designed life of pavement structures with reclaimed asphalt. The evaluation included the results of laboratory tests (i.e., the air voids content, effective asphalt content, properties of recovered asphalt (penetration, softening point), stiffness, and resistance to fatigue of bituminous mixtures). Calculations of the design life of the structure were made using the criteria according to the 2004 AASHTO specifications for fatigue life and the Asphalt Institute for subgrade deformation. In addition, calculations were carried out using the French method. The analyses allowed for a comprehensive evaluation of the asphalt concrete mixture in the analyzed scope. The evaluation of the fatigue life of AC22P and ACWMS16 mixtures with 50% content of reclaimed asphalt as well as the results of the calculations of design life of the structure indicated positive effects. The tests have been carried out within the framework of the research project dedicated to hot recycling entitled “Reclaimed asphalt pavement: Innovative technology of bituminous mixtures using material from reclaimed asphalt pavement”. Full article

(This article belongs to the Special Issue Achievements and Prospects of Advanced Pavement Materials Technologies)

► Show Figures

Figure 1

14 pages, 7896 KiB

Open AccessArticle

Potential of TCPInSAR in Monitoring Linear Infrastructure with a Small Dataset of SAR Images: Application of the Donghai Bridge, China

by Lei Zhang, Qian Sun and Jun Hu

Appl. Sci. 2018, 8(3), 425; https://doi.org/10.3390/app8030425 - 19 Mar 2018

Cited by 24 | Viewed by 5313

Abstract

Reliably monitoring deformation associated with linear infrastructures, such as long-span bridges, is vitally important to assess their structural health. In this paper, we attempt to employ satellite interferometric synthetic aperture radar (InSAR) to map the deformation of Donghai Bridge over a half of [...] Read more.

Reliably monitoring deformation associated with linear infrastructures, such as long-span bridges, is vitally important to assess their structural health. In this paper, we attempt to employ satellite interferometric synthetic aperture radar (InSAR) to map the deformation of Donghai Bridge over a half of an annual cycle. The bridge, as the fourth longest cross-sea bridge in the world, located in the north of Hangzhou Bay, East China Sea where the featureless sea surface largely occupied the radar image raises challenges to accurately co-register the coherent points along the bridge. To tackle the issues due to co-registration and the limited number of synthetic aperture radar (SAR) images, we adopt the termed temporarily-coherent point (TCP) InSAR (TCPInSAR) technique to process the radar images. TCPs that are not necessarily coherent during the whole observation period can be identified within every two SAR acquisitions during the co-registration procedure based on the statistics of azimuth and range offsets. In the process, co-registration is performed only using the offsets of these TCPs, leading to improved interferometric phases and the local Delaunay triangulation is used to construct point pairs to reduce the atmospheric artifacts along the bridge. With the TCPInSAR method the deformation rate along the bridge is estimated with no need of phase unwrapping. The achieved result reveals that the Donghai Bridge suffered a line-of-sight (LOS) deformation rate up to −2.3 cm/year from January 2009 to July 2009 at the cable-stayed part, which is likely due to the thermal expansion of cables. Full article

► Show Figures

Figure 1

15 pages, 4774 KiB

Open AccessArticle

Development and Characterization of Two-Dimensional Gratings for Single-Shot X-ray Phase-Contrast Imaging

by Margarita Zakharova, Vitor Vlnieska, Heike Fornasier, Martin Börner, Tomy dos Santos Rolo, Jürgen Mohr and Danays Kunka

Appl. Sci. 2018, 8(3), 468; https://doi.org/10.3390/app8030468 - 18 Mar 2018

Cited by 11 | Viewed by 6558

Abstract

Single-shot grating-based phase-contrast imaging techniques offer additional contrast modalities based on the refraction and scattering of X-rays in a robust and versatile configuration. The utilization of a single optical element is possible in such methods, allowing the shortening of the acquisition time and [...] Read more.

Single-shot grating-based phase-contrast imaging techniques offer additional contrast modalities based on the refraction and scattering of X-rays in a robust and versatile configuration. The utilization of a single optical element is possible in such methods, allowing the shortening of the acquisition time and increasing flux efficiency. One of the ways to upgrade single-shot imaging techniques is to utilize customized optical components, such as two-dimensional (2D) X-ray gratings. In this contribution, we present the achievements in the development of 2D gratings with UV lithography and gold electroplating. Absorption gratings represented by periodic free-standing gold pillars with lateral structure sizes from 5 µm to 25 µm and heights from 5 µm to 28 µm have shown a high degree of periodicity and defect-free patterns. Grating performance was tested in a radiographic setup using a self-developed quality assessment algorithm based on the intensity distribution histograms. The algorithm allows the final user to estimate the suitability of a specific grating to be used in a particular setup. Full article

(This article belongs to the Special Issue Advanced EUV and X-Ray Optics)

► Show Figures

Figure 1

19 pages, 7683 KiB

Open AccessArticle

Measuring Identification and Quantification Errors in Spectral CT Material Decomposition

by Aamir Younis Raja, Mahdieh Moghiseh, Christopher J. Bateman, Niels De Ruiter, Benjamin Schon, Nanette Schleich, Tim B. F. Woodfield, Anthony P. H. Butler and Nigel G. Anderson

Appl. Sci. 2018, 8(3), 467; https://doi.org/10.3390/app8030467 - 18 Mar 2018

Cited by 18 | Viewed by 6080

Abstract

Material decomposition methods are used to identify and quantify multiple tissue components in spectral CT but there is no published method to quantify the misidentification of materials. This paper describes a new method for assessing misidentification and mis-quantification in spectral CT. We scanned [...] Read more.

Material decomposition methods are used to identify and quantify multiple tissue components in spectral CT but there is no published method to quantify the misidentification of materials. This paper describes a new method for assessing misidentification and mis-quantification in spectral CT. We scanned a phantom containing gadolinium (1, 2, 4, 8 mg/mL), hydroxyapatite (54.3, 211.7, 808.5 mg/mL), water and vegetable oil using a MARS spectral scanner equipped with a poly-energetic X-ray source operated at 118 kVp and a CdTe Medipix3RX camera. Two imaging protocols were used; both with and without 0.375 mm external brass filter. A proprietary material decomposition method identified voxels as gadolinium, hydroxyapatite, lipid or water. Sensitivity and specificity information was used to evaluate material misidentification. Biological samples were also scanned. There were marked differences in identification and quantification between the two protocols even though spectral and linear correlation of gadolinium and hydroxyapatite in the reconstructed images was high and no qualitative segmentation differences in the material decomposed images were observed. At 8 mg/mL, gadolinium was correctly identified for both protocols, but concentration was underestimated by over half for the unfiltered protocol. At 1 mg/mL, gadolinium was misidentified in 38% of voxels for the filtered protocol and 58% of voxels for the unfiltered protocol. Hydroxyapatite was correctly identified at the two higher concentrations for both protocols, but mis-quantified for the unfiltered protocol. Gadolinium concentration as measured in the biological specimen showed a two-fold difference between protocols. In future, this methodology could be used to compare and optimize scanning protocols, image reconstruction methods, and methods for material differentiation in spectral CT. Full article

(This article belongs to the Special Issue Hyper- and Multi-Spectral Imaging)

► Show Figures

Figure 1

11 pages, 1109 KiB

Open AccessArticle

An Interference Cancellation Scheme for High Reliability Based on MIMO Systems

by Jae-Hyun Ro, Sung-Soon Park and Hyoung-Kyu Song

Appl. Sci. 2018, 8(3), 466; https://doi.org/10.3390/app8030466 - 18 Mar 2018

Cited by 2 | Viewed by 2906

Abstract

This article proposes a new interference cancellation scheme in a half-duplex based two-path relay system. In the conventional two-path relay system, inter-relay-interference (IRI) which severely degrades the error performances at a destination occurs because a source and a relay transmit signals simultaneously at [...] Read more.

This article proposes a new interference cancellation scheme in a half-duplex based two-path relay system. In the conventional two-path relay system, inter-relay-interference (IRI) which severely degrades the error performances at a destination occurs because a source and a relay transmit signals simultaneously at a specific time. The proposed scheme removes the IRI at a relay for higher signal-to-interference plus noise ratio (SINR) to receive interference free signal at a destination, unlike the conventional relay system, which removes IRI at a destination. To handle the IRI, the proposed scheme uses multiple-input multiple-output (MIMO) signal detection at the relays and it makes low-complexity signal processing at a destination which is a usually mobile user. At the relays, the proposed scheme uses the low-complexity QR decomposition-M algorithm (QRD-M) to optimally remove the IRI. Also, for obtaining diversity gain, the proposed scheme uses cyclic delay diversity (CDD) to transmit the signals at a source and the relays. In simulation results, the error performance for the proposed scheme is better when the distance between one relay and another relay is low unlike the conventional scheme because the QRD-M detects received signal in order of higher post signal-to-noise ratio (SNR). Full article

► Show Figures

Figure 1

27 pages, 2323 KiB

Open AccessArticle

NMR-MPar: A Fault-Tolerance Approach for Multi-Core and Many-Core Processors

by Vanessa Vargas, Pablo Ramos, Jean-Francois Méhaut and Raoul Velazco

Appl. Sci. 2018, 8(3), 465; https://doi.org/10.3390/app8030465 - 17 Mar 2018

Cited by 18 | Viewed by 4827

Abstract

Multi-core and many-core processors are a promising solution to achieve high performance by maintaining a lower power consumption. However, the degree of miniaturization makes them more sensitive to soft-errors. To improve the system reliability, this work proposes a fault-tolerance approach based on redundancy [...] Read more.

Multi-core and many-core processors are a promising solution to achieve high performance by maintaining a lower power consumption. However, the degree of miniaturization makes them more sensitive to soft-errors. To improve the system reliability, this work proposes a fault-tolerance approach based on redundancy and partitioning principles called N-Modular Redundancy and M-Partitions (NMR-MPar). By combining both principles, this approach allows multi-/many-core processors to perform critical functions in mixed-criticality systems. Benefiting from the capabilities of these devices, NMR-MPar creates different partitions that perform independent functions. For critical functions, it is proposed that N partitions with the same configuration participate of an N-modular redundancy system. In order to validate the approach, a case study is implemented on the KALRAY Multi-Purpose Processing Array (MPPA)-256 many-core processor running two parallel benchmark applications. The traveling salesman problem and matrix multiplication applications were selected to test different device’s resources. The effectiveness of NMR-MPar is assessed by software-implemented fault-injection. For evaluation purposes, it is considered that the system is intended to be used in avionics. Results show the improvement of the application reliability by two orders of magnitude when implementing NMR-MPar on the system. Finally, this work opens the possibility to use massive parallelism for dependable applications in embedded systems. Full article

► Show Figures

Figure 1

19 pages, 10845 KiB

Open AccessArticle

Kinematics and Dynamics Analysis of a 3-DOF Upper-Limb Exoskeleton with an Internally Rotated Elbow Joint

by Xin Wang, Qiuzhi Song, Xiaoguang Wang and Pengzhan Liu

Appl. Sci. 2018, 8(3), 464; https://doi.org/10.3390/app8030464 - 17 Mar 2018

Cited by 24 | Viewed by 8533

Abstract

The contradiction between self-weight and load capacity of a power-assisted upper-limb exoskeleton for material hanging is unresolved. In this paper, a non-anthropomorphic 3-degree of freedom (DOF) upper-limb exoskeleton with an internally rotated elbow joint is proposed based on an anthropomorphic 5-DOF upper-limb exoskeleton [...] Read more.

The contradiction between self-weight and load capacity of a power-assisted upper-limb exoskeleton for material hanging is unresolved. In this paper, a non-anthropomorphic 3-degree of freedom (DOF) upper-limb exoskeleton with an internally rotated elbow joint is proposed based on an anthropomorphic 5-DOF upper-limb exoskeleton for power-assisted activity. The proposed 3-DOF upper-limb exoskeleton contains a 2-DOF shoulder joint and a 1-DOF internally rotated elbow joint. The structural parameters of the 3-DOF upper-limb exoskeleton were determined, and the differences and singularities of the two exoskeletons were analyzed. The workspace, the joint torques and the power consumption of two exoskeletons were analyzed by kinematics and dynamics, and an exoskeleton prototype experiment was performed. The results showed that, compared with a typical anthropomorphic upper-limb exoskeleton, the non-anthropomorphic 3-DOF upper-limb exoskeleton had the same actual workspace; eliminated singularities within the workspace; improved the elbow joint force situation; and the maximum elbow joint torque, elbow external-flexion/internal-extension and shoulder flexion/extension power consumption were significantly reduced. The proposed non-anthropomorphic 3-DOF upper-limb exoskeleton can be applied to a power-assisted upper-limb exoskeleton in industrial settings. Full article

(This article belongs to the Section Mechanical Engineering)

► Show Figures

Figure 1

15 pages, 3482 KiB

Open AccessArticle

Extraction of Coal and Gangue Geometric Features with Multifractal Detrending Fluctuation Analysis

by Kai Liu, Xi Zhang and YangQuan Chen

Appl. Sci. 2018, 8(3), 463; https://doi.org/10.3390/app8030463 - 17 Mar 2018

Cited by 39 | Viewed by 5287

Abstract

The separation of coal and gangue is an important process of the coal preparation technology. The conventional way of manual selection and separation of gangue from the raw coal can be replaced by computer vision technology. In the literature, research on image recognition [...] Read more.

The separation of coal and gangue is an important process of the coal preparation technology. The conventional way of manual selection and separation of gangue from the raw coal can be replaced by computer vision technology. In the literature, research on image recognition and classification of coal and gangue is mainly based on the grayscale and texture features of the coal and gangue. However, there are few studies on characteristics of coal and gangue from the perspective of their outline differences. Therefore, the multifractal detrended fluctuation analysis (MFDFA) method is introduced in this paper to extract the geometric features of coal and gangue. Firstly, the outline curves of coal and gangue in polar coordinates are detected and achieved along the centroid, thereby the multifractal characteristics of the series are analyzed and compared. Subsequently, the modified local singular spectrum widths

Δ h

of the outline curve series are extracted as the characteristic variables of the coal and gangue for pattern recognition. Finally, the extracted geometric features by MFDFA combined with the grayscale and texture features of the images are compared with other methods, indicating that the recognition rate of coal gangue images can be increased by introducing the geometric features. Full article

(This article belongs to the Special Issue Fractal Based Information Processing and Recognition)

► Show Figures

Figure 1

10 pages, 2654 KiB

Open AccessArticle

Plasmonic Filter and Demultiplexer Based on Square Ring Resonator

by Zhaojian Zhang, Junbo Yang, Xin He, Yunxin Han, Jingjing Zhang, Jie Huang and Dingbo Chen

Appl. Sci. 2018, 8(3), 462; https://doi.org/10.3390/app8030462 - 17 Mar 2018

Cited by 38 | Viewed by 5411

Abstract

A ring resonator is a basic component of traditional photonic integrated circuits (PIC), which has been, however, found difficult to be applied efficiently in high-compact plasmonic metal-insulator-metal (MIM) systems. Here, based on a plasmonic band-stop filter with a square ring resonator (SRR), a [...] Read more.

A ring resonator is a basic component of traditional photonic integrated circuits (PIC), which has been, however, found difficult to be applied efficiently in high-compact plasmonic metal-insulator-metal (MIM) systems. Here, based on a plasmonic band-stop filter with a square ring resonator (SRR), a novel side-coupling method is introduced both numerically and theoretically to achieve a drop in the resonant wavelength in the SRR with considerable efficiency. By introducing the reflector structure, the performance can be appreciably improved. Besides, this structure also has potential for sensing and switching. Finally, a dual demultiplexer based on SRRs is realized at telecommunication wavelengths with comparable performance, which makes it possible to apply ring resonators in on-chip plasmonic wavelength division multiplex (WDM) networks. This work is valuable for PIC design, and will promote the on-chip plasmonic system progress. Full article

(This article belongs to the Special Issue Integrated Photonic and Plasmonic Devices Based on Slot Waveguides)

► Show Figures

Figure 1

19 pages, 5265 KiB

Open AccessArticle

Parameters Studies on Surface Initiated Rolling Contact Fatigue of Turnout Rails by Three-Level Unreplicated Saturated Factorial Design

by Xiaochuan Ma, Ping Wang, Jingmang Xu and Rong Chen

Appl. Sci. 2018, 8(3), 461; https://doi.org/10.3390/app8030461 - 17 Mar 2018

Cited by 14 | Viewed by 4713

Abstract

Surface initiated rolling contact fatigue (RCF), mainly characterized by cracks and material stripping, is a common type of damage to turnout rails, which can not only shorten service life of turnout but also lead to poor running safety of vehicle. The rail surface [...] Read more.

Surface initiated rolling contact fatigue (RCF), mainly characterized by cracks and material stripping, is a common type of damage to turnout rails, which can not only shorten service life of turnout but also lead to poor running safety of vehicle. The rail surface initiated RCF of turnouts is caused by a long-term accumulation, the size and distribution of which are related to the dynamic parameters of the complicated vehicle-turnout system. In order to simulate the accumulation of rail damage, some random samples of dynamic parameters significantly influencing it should be input. Based on the three-level unreplicated saturated factorial design, according to the evaluation methods of H, P and B statistic values, six dynamic parameters that influence the rail surface initiated RCF in turnouts, namely running speed of vehicle, axle load, wheel-rail profiles, integral vertical track stiffness and wheel-rail friction coefficient, are obtained by selecting 13 dynamic parameters significantly influencing the dynamic vehicle-turnout interaction as the analysis factors, considering four dynamic response results, i.e., the normal wheel-rail contact force, longitudinal creep force, lateral creep force and wheel-rail contact patch area as the observed parameters. In addition, the rail surface initiated RCF behavior in turnouts under different wheel-rail creep conditions is analyzed, considering the relative motion of stock/switch rails. The results show that the rail surface initiated RCF is mainly caused by the tangential stress being high under small creep conditions, the normal and tangential stresses being high under large creep conditions, and the normal stress being high under pure spin creep conditions. Full article

(This article belongs to the Section Mechanical Engineering)

► Show Figures

Figure 1

3 pages, 155 KiB

Open AccessEditorial

Special Issue on Solid State Lasers Materials, Technologies and Applications

by Federico Pirzio

Appl. Sci. 2018, 8(3), 460; https://doi.org/10.3390/app8030460 - 17 Mar 2018

Cited by 1 | Viewed by 2940

Abstract

Even though more than half a century has already passed since the first demonstration of laser action in ruby crystal, solid-state lasers are still a hot research topic.[...] Full article

(This article belongs to the Special Issue Solid State Lasers Materials, Technologies and Applications)

15 pages, 10478 KiB

Open AccessFeature PaperArticle

Extraction of Independent Structural Images for Principal Component Thermography

by Dmitry Gavrilov and Roman Gr. Maev

Appl. Sci. 2018, 8(3), 459; https://doi.org/10.3390/app8030459 - 17 Mar 2018

Cited by 7 | Viewed by 4400

Abstract

Thermography is a powerful tool for non-destructive testing of a wide range of materials. Thermography has a number of approaches differing in both experiment setup and the way the collected data are processed. Among such approaches is the Principal Component Thermography (PCT) method, [...] Read more.

Thermography is a powerful tool for non-destructive testing of a wide range of materials. Thermography has a number of approaches differing in both experiment setup and the way the collected data are processed. Among such approaches is the Principal Component Thermography (PCT) method, which is based on the statistical processing of raw thermal images collected by thermal camera. The processed images (principal components or empirical orthogonal functions) form an orthonormal basis, and often look like a superposition of all possible structural features found in the object under inspection—i.e., surface heating non-uniformity, internal defects and material structure. At the same time, from practical point of view it is desirable to have images representing independent structural features. The work presented in this paper proposes an approach for separation of independent image patterns (archetypes) from a set of principal component images. The approach is demonstrated in the application of inspection of composite materials as well as the non-invasive analysis of works of art. Full article

(This article belongs to the Special Issue Novel Ideas for Infrared Thermography also Applied in Integrated Approaches)

► Show Figures

Graphical abstract

19 pages, 1144 KiB

Open AccessArticle

A Kernel Least Mean Square Algorithm Based on Randomized Feature Networks

by Yuqi Liu, Chao Sun and Shouda Jiang

Appl. Sci. 2018, 8(3), 458; https://doi.org/10.3390/app8030458 - 16 Mar 2018

Cited by 5 | Viewed by 4097

Abstract

To construct an online kernel adaptive filter in a non-stationary environment, we propose a randomized feature networks-based kernel least mean square (KLMS-RFN) algorithm. In contrast to the Gaussian kernel, which implicitly maps the input to an infinite dimensional space in theory, the randomized [...] Read more.

To construct an online kernel adaptive filter in a non-stationary environment, we propose a randomized feature networks-based kernel least mean square (KLMS-RFN) algorithm. In contrast to the Gaussian kernel, which implicitly maps the input to an infinite dimensional space in theory, the randomized feature mapping transform inputs samples into a relatively low-dimensional feature space, where the transformed samples are approximately equivalent to those in the feature space using a shift-invariant kernel. The mean square convergence process of the proposed algorithm is investigated under the uniform convergence analysis method of a nonlinear adaptive filter. The computational complexity is also evaluated. In Lorenz time series prediction and nonstationary channel equalization scenarios, the simulation results demonstrate the effectiveness of the proposed algorithm. Full article

► Show Figures

Figure 1

16 pages, 2527 KiB

Open AccessArticle

Design of SBS-Modified Bitumen Stabilizer Powder Based on the Vulcanization Mechanism

by Wengang Zhang, Longting Ding and Zhirong Jia

Appl. Sci. 2018, 8(3), 457; https://doi.org/10.3390/app8030457 - 16 Mar 2018

Cited by 15 | Viewed by 6167

Abstract

In order to improve the problem of the bad thermal storage stability of Styrene-Butadiene-Styrene Block Copolymer Modified Bitumen (SBS-modified bitumen), the vulcanization reaction was selected as the basic mechanism for the research and development of the stabilizer. Sulfur, tetramethylthiuram disulfide (TMTD), zinc oxide, [...] Read more.

In order to improve the problem of the bad thermal storage stability of Styrene-Butadiene-Styrene Block Copolymer Modified Bitumen (SBS-modified bitumen), the vulcanization reaction was selected as the basic mechanism for the research and development of the stabilizer. Sulfur, tetramethylthiuram disulfide (TMTD), zinc oxide, butylated hydroxytoluene (BHT), kaolin (Al₂O₃·2SiO₂·2H₂O) and carbon-white (SiO₂) were used as raw materials, and 32 kinds of components with different contents of raw materials were designed. The 48-h segregation softening point and other modified bitumen technical indicators, such as ductility, penetration, penetration index, viscosity, and so on, were tested and analyzed. The fluorescence microscope test was also conducted to explore the crosslinking situation based on the vulcanization reaction. The results show that the component with good performance of the SBS-modified bitumen stabilizer powder was S:TMTD:ZnO:BHT: Al₂O₃·2SiO₂·2H₂O = 60:16:4:20:1250 or S:TMTD:ZnO:BHT:SiO₂ = 60:16:4:20:625. The optimum content of stabilizer powder was 0.9% (S/modified bitumen). The stabilizer was dry powder and can be directly put into bitumen. It can cross-link SBS and especially has an effect on preventing SBS segregation. The technical performance of SBS-modified bitumen with stabilizer powder, such as hot temperature performance, low temperature performance, anti-aging performance and thermal storage stability, all meet the relevant specifications. Full article

(This article belongs to the Special Issue Achievements and Prospects of Advanced Pavement Materials Technologies)

► Show Figures

Figure 1

12 pages, 1866 KiB

Open AccessArticle

Influence of Substrate Stage Temperature and Rotation Rate on the Magneto-Optical Quality of RF-Sputtered Bi_2.1Dy_0.9Fe_3.9Ga_1.1O₁₂ Garnet Thin Films

by M. Nur-E-Alam, Mikhail Vasiliev and Kamal Alameh

Appl. Sci. 2018, 8(3), 456; https://doi.org/10.3390/app8030456 - 16 Mar 2018

Cited by 3 | Viewed by 3878

Abstract

Highly bismuth-substituted iron garnet thin films are prepared on quartz substrates by using a radio frequency (RF) magnetron sputtering technique. We study the factors (process parameters associated with the RF magnetron sputter deposition technique) affecting the magneto-optical (MO) properties of ferrite garnet films [...] Read more.

Highly bismuth-substituted iron garnet thin films are prepared on quartz substrates by using a radio frequency (RF) magnetron sputtering technique. We study the factors (process parameters associated with the RF magnetron sputter deposition technique) affecting the magneto-optical (MO) properties of ferrite garnet films of composition Bi_2.1Dy_0.9Fe_3.9Ga_1.1O₁₂. All films show high MO response across the visible range of wavelengths after being annealed. In particular, the effects of substrate stage temperature and rotation rate on the various properties of films are studied. Experimental results reveal that the characteristics of garnet films of this type can be tuned and optimized for use in various magnetic field-driven nanophotonics and integrated optics devices, and that, at a substrate stage rotation rate near 16 revolutions per minute, the MO quality of the developed MO films is the best, in comparison with films deposited at other rotation rates. To the best of our knowledge, this is the first report on the effects of deposition parameters on the properties of garnet films of this stoichiometry. Full article

(This article belongs to the Section Materials Science and Engineering)

► Show Figures

Figure 1

26 pages, 3204 KiB

Open AccessArticle

A Hybrid Method for Optimal Siting and Sizing of Battery Energy Storage Systems in Unbalanced Low Voltage Microgrids

by Guido Carpinelli, Fabio Mottola, Daniela Proto, Angela Russo and Pietro Varilone

Appl. Sci. 2018, 8(3), 455; https://doi.org/10.3390/app8030455 - 16 Mar 2018

Cited by 26 | Viewed by 4254

Abstract

This paper deals with the problem of optimal allocation (siting and sizing) of storage resources in unbalanced three-phase low voltage microgrids. The siting and sizing problem is formulated as a mixed, non-linear, constrained optimization problem whose objective function deals with economic issues and [...] Read more.

This paper deals with the problem of optimal allocation (siting and sizing) of storage resources in unbalanced three-phase low voltage microgrids. The siting and sizing problem is formulated as a mixed, non-linear, constrained optimization problem whose objective function deals with economic issues and whose constraints involve technical limitations of both network and distributed resources. Emphasis is given to the power quality issue with particular attention to unbalance reduction and voltage profile improvement. Technological issues, such as those related to the preservation of batteries’ lifetime, were also taken into account. The planning problem is solved by means of a genetic algorithm which includes an inner algorithm based on sequential quadratic programming. In order to limit the processing time while maintaining reasonable accuracy, the genetic algorithm search space is significantly reduced identifying a subset of candidate buses for the siting of the storage resources. The Inherent Structure Theory of Networks and the Loading Constraints Criterion were used to identify the candidate buses. The proposed method has been applied to a low voltage test network demonstrating the effectiveness of the procedure in terms of computational burden while also preserving the accuracy of the solution. Full article

(This article belongs to the Special Issue Developing and Implementing Smart Grids: Novel Technologies, Techniques and Models)

► Show Figures

Figure 1

11 pages, 3029 KiB

Open AccessArticle

An Investigation of the High Efficiency Estimation Approach of the Large-Scale Scattered Point Cloud Normal Vector

by Xianglin Meng, Wantao He and Junyan Liu

Appl. Sci. 2018, 8(3), 454; https://doi.org/10.3390/app8030454 - 16 Mar 2018

Cited by 4 | Viewed by 3560

Abstract

The normal vector estimation of the large-scale scattered point cloud (LSSPC) plays an important role in point-based shape editing. However, the normal vector estimation for LSSPC cannot meet the great challenge of the sharp increase of the point cloud that is mainly attributed [...] Read more.

The normal vector estimation of the large-scale scattered point cloud (LSSPC) plays an important role in point-based shape editing. However, the normal vector estimation for LSSPC cannot meet the great challenge of the sharp increase of the point cloud that is mainly attributed to its low computational efficiency. In this paper, a novel, fast method-based on bi-linear interpolation is reported on the normal vector estimation for LSSPC. We divide the point sets into many small cubes to speed up the local point search and construct interpolation nodes on the isosurface expressed by the point cloud. On the premise of calculating the normal vectors of these interpolated nodes, a normal vector bi-linear interpolation of the points in the cube is realized. The proposed approach has the merits of accurate, simple, and high efficiency, because the algorithm only needs to search neighbor and calculates normal vectors for interpolation nodes that are usually far less than the point cloud. The experimental results of several real and simulated point sets show that our method is over three times faster than the Elliptic Gabriel Graph-based method, and the average deviation is less than 0.01 mm. Full article

(This article belongs to the Section Mechanical Engineering)

► Show Figures

Figure 1

29 pages, 16527 KiB

Open AccessArticle

Development of a High-Fidelity Model for an Electrically Driven Energy Storage Flywheel Suitable for Small Scale Residential Applications

by Mustafa E. Amiryar, Keith R. Pullen and Daniel Nankoo

Appl. Sci. 2018, 8(3), 453; https://doi.org/10.3390/app8030453 - 16 Mar 2018

Cited by 29 | Viewed by 7581

Abstract

Energy storage systems (ESS) are key elements that can be used to improve electrical system efficiency by contributing to balance of supply and demand. They provide a means for enhancing the power quality and stability of electrical systems. They can enhance electrical system [...] Read more.

Energy storage systems (ESS) are key elements that can be used to improve electrical system efficiency by contributing to balance of supply and demand. They provide a means for enhancing the power quality and stability of electrical systems. They can enhance electrical system flexibility by mitigating supply intermittency, which has recently become problematic, due to the increased penetration of renewable generation. Flywheel energy storage systems (FESS) are a technology in which there is gathering interest due to a number of advantages offered over other storage solutions. These technical qualities attributed to flywheels include high power density, low environmental impact, long operational life, high round-trip efficiency and high cycle life. Furthermore, when configured in banks, they can store MJ levels of energy without any upper limit. Flywheels configured for grid connected operation are systems comprising of a mechanical part, the flywheel rotor, bearings and casings, and the electric drive part, inclusive of motor-generator (MG) and power electronics. This contribution focusses on the modelling and simulation of a high inertia FESS for energy storage applications which has the potential for use in the residential sector in more challenging situations, a subject area in which there are few publications. The type of electrical machine employed is a permanent magnet synchronous motor (PMSM) and this, along with the power electronics drive, is simulated in the MATLAB/Simulink environment. A brief description of the flywheel structure and applications are given as a means of providing context for the electrical modelling and simulation reported. The simulated results show that the system run-down losses are 5% per hour, with overall roundtrip efficiency of 88%. The flywheel speed and energy storage pattern comply with the torque variations, whilst the DC-bus voltage remains constant and stable within ±3% of the rated voltage, regardless of load fluctuations. Full article

(This article belongs to the Special Issue Smart Home and Energy Management Systems)

► Show Figures

Figure 1

19 pages, 5138 KiB

Open AccessArticle

A Novel Distributed Large-Scale Demand Response Scheme in High Proportion Renewable Energy Sources Integration Power Systems

by Shuai Fan, Guangyu He, Kunqi Jia and Zhihua Wang

Appl. Sci. 2018, 8(3), 452; https://doi.org/10.3390/app8030452 - 16 Mar 2018

Cited by 19 | Viewed by 4313

Abstract

Large-scale demand response (DR) is a useful regulatory method used in high proportion renewable energy sources (RES) integration power systems. Current incentive-based DR schemes are unsuitable for large-scale DR due to their centralized formulation. This paper proposes a distributed scheme to support large-scale [...] Read more.

Large-scale demand response (DR) is a useful regulatory method used in high proportion renewable energy sources (RES) integration power systems. Current incentive-based DR schemes are unsuitable for large-scale DR due to their centralized formulation. This paper proposes a distributed scheme to support large-scale implementation of DR. To measure DR performance, this paper proposes the customer directrix load (CDL), which is a desired load profile, to replace the customer baseline load (CBL). The uniqueness of CDL makes it more suitable for distributed schemes, while numerous CBLs have to be calculated in a centralized manner to ensure fairness. To allocate DR tasks and rebates, this paper proposes a distributed approach, where the load serving entity (LSE) only needs to publish a total rebate and corresponding CDL. As for each customer, s/he needs to claim an ideal rebate ratio that ranges from 0 to 1, which indicates the proportion of rebate s/he wants to get from LSE. The rebate value for each customer also determines his or her DR task. Then, the process of customer claims for the ideal rebate ratio is modeled as a non-cooperative game, and the Nash equilibrium is proved to exist. The Gossip algorithm is improved in this paper to be suitable for socially connected networks, and the entire game process is distributed. Finally, a large-scale DR system is formulated. The simulation results show that the proposed DR can promote the consumption of RES. Additionally, this scheme is suitable for large-scale customer systems, and the distributed game process is effective. Full article

(This article belongs to the Special Issue Renewable Energy 2018)

► Show Figures

Figure 1

18 pages, 9648 KiB

Open AccessArticle

Transmission of High Frequency Vibrations in Rotating Systems. Application to Cavitation Detection in Hydraulic Turbines

by David Valentín, Alexandre Presas, Mònica Egusquiza, Carme Valero and Eduard Egusquiza

Appl. Sci. 2018, 8(3), 451; https://doi.org/10.3390/app8030451 - 16 Mar 2018

Cited by 23 | Viewed by 5556

Abstract

One of the main causes of damage in hydraulic turbines is cavitation. While not all cavitation appearing in a turbine is of a destructive type, erosive cavitation can severely affect the structure, thus increasing maintenance costs and reducing the remaining useful life of [...] Read more.

One of the main causes of damage in hydraulic turbines is cavitation. While not all cavitation appearing in a turbine is of a destructive type, erosive cavitation can severely affect the structure, thus increasing maintenance costs and reducing the remaining useful life of the machine. Of all types of cavitation, the maximum erosion occurs when clouds of bubbles collapse on the runner surface (cloud cavitation). When this occurs it is associated with a substantial increase in noise, and vibrations that are propagated everywhere throughout the machine. The generation of these cavitation clouds may occur naturally or it may be the response to a periodic pressure fluctuation, like the rotor/stator interaction in a hydraulic turbine. Erosive bubble cavitation generates high-frequency vibrations that are modulated by the shedding frequency. Therefore, the methods for the detection of erosive cavitation in hydraulic turbines are based on the measurement and demodulation of high-frequency vibrations. In this paper, the feasibility of detecting erosive cavitation in hydraulic turbines is investigated experimentally in a rotating disk system, which represents a simplified hydraulic turbine structure. The test rig used consists of a rotating disk submerged in a tank of water and confined with nearby axial and radial rigid surfaces. The excitation patterns produced by cloud cavitation are reproduced with a PZT (piezoelectric patch) located on the disk. These patterns include pseudo-random excitations of different frequency bands modulated by one low carrier frequency, which model the erosive cavitation characteristics. Different types of sensors have been placed in the stationary and in the rotating parts (accelerometers, acoustic emission (AE), and a microphone) in order to detect the excitation pattern. The results obtained for all the sensors tested have been compared in detail for the different excitation patterns applied to the disk. With this information, the best location and type of sensor to detect the different excitations have been identified. This study permits improving the actual technique of detecting erosive cavitation in hydraulic turbines and, therefore, to avoid operation under these circumstances. Full article

(This article belongs to the Section Acoustics and Vibrations)

► Show Figures

Figure 1

13 pages, 6041 KiB

Open AccessArticle

A Pseudo-3D Model for Electromagnetic Acoustic Transducers (EMATs)

by Wuliang Yin, Yuedong Xie, Zhigang Qu and Zenghua Liu

Appl. Sci. 2018, 8(3), 450; https://doi.org/10.3390/app8030450 - 15 Mar 2018

Cited by 5 | Viewed by 4870

Abstract

Previous methods for modelling Rayleigh waves produced by a meander-line-coil electromagnetic acoustic transducer (EMAT) consisted mostly of two-dimensional (2D) simulations that focussed on the vertical plane of the material. This paper presents a pseudo-three-dimensional (3D) model that extends the simulation space to both [...] Read more.

Previous methods for modelling Rayleigh waves produced by a meander-line-coil electromagnetic acoustic transducer (EMAT) consisted mostly of two-dimensional (2D) simulations that focussed on the vertical plane of the material. This paper presents a pseudo-three-dimensional (3D) model that extends the simulation space to both vertical and horizontal planes. For the vertical plane, we combines analytical and finite-difference time-domain (FDTD) methods to model Rayleigh waves’ propagation within an aluminium plate and their scattering behaviours by cracks. For the horizontal surface plane, we employ an analytical method to investigate the radiation pattern of Rayleigh waves at various depths. The experimental results suggest that the models and the modelling techniques are valid. Full article

(This article belongs to the Special Issue Modelling, Simulation and Data Analysis in Acoustical Problems)

► Show Figures

Figure 1

11 pages, 4249 KiB

Open AccessArticle

Numerical and Experimental Study on Multi-Focal Metallic Fresnel Zone Plates Designed by the Phase Selection Rule via Virtual Point Sources

by Jinseob Kim, Hyuntai Kim, Gun-Yeal Lee, Juhwan Kim, Byoungho Lee and Yoonchan Jeong

Appl. Sci. 2018, 8(3), 449; https://doi.org/10.3390/app8030449 - 15 Mar 2018

Cited by 21 | Viewed by 5102

Abstract

We propose a novel design method for multi-focal metallic Fresnel zone plates (MFZPs), which exploits the phase selection rule by putting virtual point sources (VPSs) at the desired focal points distant to the MFZP plane. The phase distribution at the MFZP plane reciprocally [...] Read more.

We propose a novel design method for multi-focal metallic Fresnel zone plates (MFZPs), which exploits the phase selection rule by putting virtual point sources (VPSs) at the desired focal points distant to the MFZP plane. The phase distribution at the MFZP plane reciprocally formed by the VPSs was quantized in a binary manner based on the phase selection rule, thereby leading to a corresponding on-off amplitude pattern for the targeted MFZP. The resultant phase distribution was dependent on the complex amplitudes of the VPSs, so that they could be determined from the perspective of both multi-focal functionality and fabrication feasibility. As a typical example, we utilized the particle swarm optimization algorithm to determine them. Based on the proposed method, we designed and numerically analyzed two types of novel MFZPs—one for a monochromatic multi-focal application and the other for a multi-chromatic mono-focal application—verifying the effectiveness and validity of the proposed method. We also fabricated them onto Au-deposited glass substrates, using electron beam evaporation and a focused ion beam milling process. We experimentally characterized them and also verified that they successfully demonstrated their feasibilities. The former produced distinct hot spots at three different focal distances of 10, 15, and 20

μ m

for monochromatic incidence at 650 nm, and the latter produced a single hot spot at a focal distance of 15

μ m

for multi-chromatic incidence at 660, 532, and 473 nm. The experimental results were also in good agreement with their corresponding numerical results. We expect that both MFZPs will have various applications, such as laser micromachining, optical trapping, biomedical sensing, confocal collimation, achromatic optics, etc. Full article

(This article belongs to the Section Optics and Lasers)

► Show Figures

Figure 1

15 pages, 3835 KiB

Open AccessFeature PaperArticle

Simplified Modeling Strategy for the Thermomechanical Analysis of Massive Reinforced Concrete Structures at an Early Age

by Jacky Mazars, Stéphane Grange and Matthieu Briffaut

Appl. Sci. 2018, 8(3), 448; https://doi.org/10.3390/app8030448 - 15 Mar 2018

Cited by 7 | Viewed by 4305

Abstract

The objective of this work is to propose a comprehensive and efficient modeling approach to simulate the entire loading program of the RG8 test (both the restrained shrinkage and mechanical parts) performed within the framework of the French national program CEOS.fr. This effort [...] Read more.

The objective of this work is to propose a comprehensive and efficient modeling approach to simulate the entire loading program of the RG8 test (both the restrained shrinkage and mechanical parts) performed within the framework of the French national program CEOS.fr. This effort was made possible by introducing a multi-fiber beam discretization that included a thermomechanical model coupled with a unilateral concrete damage model. Due to the massiveness of the test structure, the scale effect needed to be taken into account. This step could be accomplished through use of a Weibull law. Extensive results were obtained during the experiment, some of which focused on deformations and forces developed in the structure by restrained shrinkage, the times of crack appearance and opening, and the consequences of damage sustained on the residual mechanical performance of the beam. A comparison with calculation output has demonstrated the ability of our modeling approach to simulate phenomena at both global and local levels, thus confirming the relevance of model choices made. Full article

(This article belongs to the Special Issue Modelling of Early Age Cracking Risks and Serviceability of Concrete Structures)

► Show Figures

Figure 1

14 pages, 2543 KiB

Open AccessFeature PaperArticle

Comparison of Nonlinear Compensation Techniques for 400-Gb/s Coherent Multi-Band OFDM Super-Channels

by Vasiliki Vgenopoulou, Mengdi Song, Erwan Pincemin, Yves Jaouën, Stylianos Sygletos and Ioannis Roudas

Appl. Sci. 2018, 8(3), 447; https://doi.org/10.3390/app8030447 - 15 Mar 2018

Cited by 9 | Viewed by 4483

Abstract

The last few years, many studies have been published on the 3rd-order inverse Volterra series transfer function nonlinear equalizer (IVSTF-NLE) in long-haul optical communication systems. Nonetheless, no experimental work has been published on investigating the potential of the 3rd-order IVSTF-NLE for the compensation [...] Read more.

The last few years, many studies have been published on the 3rd-order inverse Volterra series transfer function nonlinear equalizer (IVSTF-NLE) in long-haul optical communication systems. Nonetheless, no experimental work has been published on investigating the potential of the 3rd-order IVSTF-NLE for the compensation of Kerr nonlinearities in a long-haul wavelength division multiplexing (WDM) system consisting of high-bit rate super-channels, as high as 400 Gb/s. In this paper, we study experimentally the performance of a 3rd-order IVSTF-NLE in a coherent optical WDM system, with a central, 400-Gb/s, 4-band, dual-polarization (DP), 16-ary quadrature amplitude modulation (QAM) orthogonal frequency division multiplexing (OFDM) super-channel. We compare its performance against the performance of the digital back-propagation split-step Fourier (DBP-SSF) method for the compensation of nonlinearities after 10 × 100 km of ITU-T G.652 standard single mode fiber (SSMF). In the second part of this paper, we compare, via Monte Carlo simulations, the performance of the 3rd-order IVSTF-NLE and the DBP-SSF method, in terms of reach extension and computational complexity, after propagation through ITU-T G.652 SSMF and a ITU-T G.655 large effective area fiber (LEAF). By means of both experimental evaluation and simulations, we show that, in the presence of strong nonlinear effects, the 3rd-order IVSTF-NLE, which uses a single step per span, performs similarly with the two-steps-per-span DBP-SSF, whereas the eight-steps-per-span DBP-SSF is only marginally better but at the vast expense of computational complexity. Full article

(This article belongs to the Special Issue DSP for Next Generation Fibre Communication Systems)

► Show Figures

Figure 1

21 pages, 1201 KiB

Open AccessArticle

Modelling the Interaction Levels in HCI Using an Intelligent Hybrid System with Interactive Agents: A Case Study of an Interactive Museum Exhibition Module in Mexico

by Ricardo Rosales, Manuel Castañón-Puga, Felipe Lara-Rosano, Josue Miguel Flores-Parra, Richard Evans, Nora Osuna-Millan and Carelia Gaxiola-Pacheco

Appl. Sci. 2018, 8(3), 446; https://doi.org/10.3390/app8030446 - 15 Mar 2018

Cited by 12 | Viewed by 5876

Abstract

Technology has become a necessity in our everyday lives and essential for completing activities we typically take for granted; technologies can assist us by completing set tasks or achieving desired goals with optimal affect and in the most efficient way, thereby improving our [...] Read more.

Technology has become a necessity in our everyday lives and essential for completing activities we typically take for granted; technologies can assist us by completing set tasks or achieving desired goals with optimal affect and in the most efficient way, thereby improving our interactive experiences. This paper presents research that explores the representation of user interaction levels using an intelligent hybrid system approach with agents. We evaluate interaction levels of Human-Computer Interaction (HCI) with the aim of enhancing user experiences. We consider the description of interaction levels using an intelligent hybrid system to provide a decision-making system to an agent that evaluates interaction levels when using interactive modules of a museum exhibition. The agents represent a high-level abstraction of the system, where communication takes place between the user, the exhibition and the environment. In this paper, we provide a means to measure the interaction levels and natural behaviour of users, based on museum user-exhibition interaction. We consider that, by analysing user interaction in a museum, we can help to design better ways to interact with exhibition modules according to the properties and behaviour of the users. An interaction-evaluator agent is proposed to achieve the most suitable representation of the interaction levels with the aim of improving user interactions to offer the most appropriate directions, services, content and information, thereby improving the quality of interaction experienced between the user-agent and exhibition-agent. Full article

(This article belongs to the Special Issue Multi-Agent Systems)

► Show Figures

Figure 1

9 pages, 867 KiB

Open AccessArticle

A Multiple-Model Particle Filter Fusion Algorithm for GNSS/DR Slide Error Detection and Compensation

by Rafael Toledo-Moreo, Carlos Colodro-Conde and Javier Toledo-Moreo

Appl. Sci. 2018, 8(3), 445; https://doi.org/10.3390/app8030445 - 15 Mar 2018

Cited by 6 | Viewed by 4046

Abstract

Continuous accurate positioning is a key element for the deployment of many advanced driver assistance systems (ADAS) and autonomous vehicle navigation. To achieve the necessary performance, global navigation satellite systems (GNSS) must be combined with other technologies. A common onboard sensor-set that allows [...] Read more.

Continuous accurate positioning is a key element for the deployment of many advanced driver assistance systems (ADAS) and autonomous vehicle navigation. To achieve the necessary performance, global navigation satellite systems (GNSS) must be combined with other technologies. A common onboard sensor-set that allows keeping the cost low, features the GNSS unit, odometry, and inertial sensors, such as a gyro. Odometry and inertial sensors compensate for GNSS flaws in many situations and, in normal conditions, their errors can be easily characterized, thus making the whole solution not only more accurate but also with more integrity. However, odometers do not behave properly when friction conditions make the tires slide. If not properly considered, the positioning perception will not be sound. This article introduces a hybridization approach that takes into consideration the sliding situations by means of a multiple model particle filter (MMPF). Tests with real datasets show the goodness of the proposal. Full article

(This article belongs to the Special Issue Road Vehicles Surroundings Supervision: On-Board Sensors and Communications)

► Show Figures

Graphical abstract

Journal Menu

Journal Browser

Appl. Sci., Volume 8, Issue 3 (March 2018) – 156 articles

Further Information

Guidelines

MDPI Initiatives

Follow MDPI