Next Issue
Previous Issue

Table of Contents

Appl. Sci., Volume 7, Issue 9 (September 2017)

  • Issues are regarded as officially published after their release is announced to the table of contents alert mailing list.
  • You may sign up for e-mail alerts to receive table of contents of newly released issues.
  • PDF is the official format for papers published in both, html and pdf forms. To view the papers in pdf format, click on the "PDF Full-text" link, and use the free Adobe Readerexternal link to open them.
Cover Story (view full-size image) The presented image are surface morphology of aluminum 1050 alloy subjected to plasma electrolytic [...] Read more.
View options order results:
result details:
Displaying articles 1-98
Export citation of selected articles as:
Open AccessEditorial
Editorial: Guided-Wave Optics
Appl. Sci. 2017, 7(9), 962; https://doi.org/10.3390/app7090962
Received: 11 September 2017 / Revised: 15 September 2017 / Accepted: 15 September 2017 / Published: 20 September 2017
Viewed by 893 | PDF Full-text (262 KB) | HTML Full-text | XML Full-text
Abstract
Guided waves represent a vast class of phenomena in which the propagation of collective excitations in various media is steered in required directions by fixed (or, sometimes, reconfigurable) conduits [...]
Full article
(This article belongs to the Special Issue Guided-Wave Optics) Printed Edition available
Open AccessArticle
Application of Artificial Neural Networks to Ship Detection from X-Band Kompsat-5 Imagery
Appl. Sci. 2017, 7(9), 961; https://doi.org/10.3390/app7090961
Received: 31 July 2017 / Revised: 10 September 2017 / Accepted: 18 September 2017 / Published: 20 September 2017
Cited by 5 | Viewed by 1542 | PDF Full-text (5024 KB) | HTML Full-text | XML Full-text
Abstract
For ship detection, X-band synthetic aperture radar (SAR) imagery provides very useful data, in that ship targets look much brighter than surrounding sea clutter due to the corner-reflection effect. However, there are many phenomena which bring out false detection in the SAR image, [...] Read more.
For ship detection, X-band synthetic aperture radar (SAR) imagery provides very useful data, in that ship targets look much brighter than surrounding sea clutter due to the corner-reflection effect. However, there are many phenomena which bring out false detection in the SAR image, such as noise of background, ghost phenomena, side-lobe effects and so on. Therefore, when ship-detection algorithms are carried out, we should consider these effects and mitigate them to acquire a better result. In this paper, we propose an efficient method to detect ship targets from X-band Kompsat-5 SAR imagery using the artificial neural network (ANN). The method produces the ship-probability map using ANN, and then detects ships from the ship-probability map by using a threshold value. For the purpose of getting an improved ship detection, we strived to produce optimal input layers used for ANN. In order to reduce phenomena related to the false detections, the non-local (NL)-means filter and median filter were utilized. The NL-means filter effectively reduced noise on SAR imagery without smoothing edges of the objects, and the median filter was used to remove ship targets in SAR imagery. Through the filtering approaches, we generated two input layers from a Kompsat-5 SAR image, and created a ship-probability map via ANN from the two input layers. When the threshold value of 0.67 was imposed on the ship-probability map, the result of ship detection from the ship-probability map was a 93.9% recall, 98.7% precision and 6.1% false alarm rate. Therefore, the proposed method was successfully applied to the ship detection from the Kompsat-5 SAR image. Full article
Figures

Figure 1

Open AccessArticle
Antimony Oxide-Doped 0.99Pb(Zr0.53Ti0.47)O3–0.01Bi(Y1−xSbx)O3 Piezoelectric Ceramics for Energy-Harvesting Applications
Appl. Sci. 2017, 7(9), 960; https://doi.org/10.3390/app7090960
Received: 10 August 2017 / Revised: 14 September 2017 / Accepted: 14 September 2017 / Published: 19 September 2017
Cited by 1 | Viewed by 1535 | PDF Full-text (3285 KB) | HTML Full-text | XML Full-text
Abstract
The effects of doping antimony oxides (Sb2O3/Sb2O5) on the ferroelectric/piezoelectric and energy-harvesting properties of 0.99Pb(Zr0.53Ti0.47)O3–0.01BiYO3 (PZT–BY) have been studied. The feasibility of doping Sb2O3 and [...] Read more.
The effects of doping antimony oxides (Sb2O3/Sb2O5) on the ferroelectric/piezoelectric and energy-harvesting properties of 0.99Pb(Zr0.53Ti0.47)O3–0.01BiYO3 (PZT–BY) have been studied. The feasibility of doping Sb2O3 and Sb2O5 into the PZT–BY ceramics has also been compared by considering factors such as sintering condition, grain size, density, and electrical properties etc. This work discusses a detailed experimental observation using Sb2O3, because Sb2O5 is relatively expensive and does not follow the stoichiometric reaction mechanism when doped in PZT–BY. The Sb2O3-doped specimens were well sintered by oxygen-rich sintering and reached a maximum density of 99.1% of the theoretical value. X-ray diffraction (XRD) analysis showed a complete solid solution for all the specimens. Scanning electron microscope (SEM) observation revealed that the addition of Sb2O3 inhibits grain growth, and exhibits a denser and finer microstructure. The 0.1 moles of Sb2O3-doped ceramic shows a sharp decrease in the dielectric constant (ε33T = 690), while the piezoelectric charge constant (d33) and electromechanical coupling factor (kp) maintained high values of 350 pC/N and 66.0% respectively. The relatively higher value of d33 and lower ε33T of the 0.99Pb(Zr0.53Ti0.47)O3–0.01Bi(Y0.9Sb0.1)O3 ceramic resulted in an optimum value of piezoelectric voltage constant (g33 = 57.4 × 10−3 Vm/N) and a high figure of merit (d33 × g33 = 20075 × 10−15 m2/N). These values are high compared to recently reported works. Therefore, Sb2O3-doped PZT–BY ceramic could be a promising candidate material for the future study of power-harvesting devices. Full article
Figures

Graphical abstract

Open AccessTechnical Note
Which Method Detects Foot Strike in Rearfoot and Forefoot Runners Accurately when Using an Inertial Measurement Unit?
Appl. Sci. 2017, 7(9), 959; https://doi.org/10.3390/app7090959
Received: 17 August 2017 / Revised: 11 September 2017 / Accepted: 15 September 2017 / Published: 19 September 2017
Cited by 6 | Viewed by 2138 | PDF Full-text (571 KB) | HTML Full-text | XML Full-text
Abstract
Accelerometers and gyroscopes are used to detect foot strike (FS), i.e., the moment when the foot first touches the ground. However, it is unclear whether different conditions (footwear hardness or foot strike pattern) influence the accuracy and precision of different FS detection methods [...] Read more.
Accelerometers and gyroscopes are used to detect foot strike (FS), i.e., the moment when the foot first touches the ground. However, it is unclear whether different conditions (footwear hardness or foot strike pattern) influence the accuracy and precision of different FS detection methods when using such micro-electromechanical sensors (MEMS). This study compared the accuracy of four published MEMS-based FS detection methods with each other and the gold standard (force plate) to establish the most accurate method with regard to different foot strike patterns and footwear conditions. Twenty-three recreational runners (12 rearfoot and 11 forefoot strikers) ran on a 15-m indoor track at their individual running speed in three footwear conditions (low to high hardness). MEMS and a force plate were sampled at a rate of 3750 Hz. Individual accuracy and precision of FS detection methods were found which were dependent on running styles and footwear conditions. Most of the methods were characterized by a delay which generally increased from rearfoot to forefoot strike pattern and from high to low midsole hardness. It can be concluded that only one of the four methods can accurately determine FS in a variety of conditions. Full article
Figures

Graphical abstract

Open AccessArticle
Gas Sensor Design Based on a Line Locked Tunable Fiber Laser and the Dual Path Correlation Spectroscopy Method
Appl. Sci. 2017, 7(9), 958; https://doi.org/10.3390/app7090958
Received: 9 August 2017 / Revised: 9 September 2017 / Accepted: 18 September 2017 / Published: 19 September 2017
Cited by 3 | Viewed by 1424 | PDF Full-text (594 KB) | HTML Full-text | XML Full-text
Abstract
In this work a hybrid gas sensor based on a tunable fiber laser and a correlation spectroscopy technique is presented. The laser is tuned by varying the temperature of a bulk silicon wafer of 85 μm thickness and, once the desired wavelength [...] Read more.
In this work a hybrid gas sensor based on a tunable fiber laser and a correlation spectroscopy technique is presented. The laser is tuned by varying the temperature of a bulk silicon wafer of 85 μ m thickness and, once the desired wavelength is reached the line, is locked by keeping fixed its temperature. According to experimental results the wafer temperature variation was in the order of 0.02 K, which induced an estimated wavelength deviation of 0.12 pm, which satisfies the high wavelength position accuracy required for gas sensing applications. Additionally, it is shown that errors due to laser intensity fluctuations can be minimized by implementing a simple dual path correlation spectroscopy stage. As a proof of the suitability of our tunable fiber laser for gas sensing applications, a C2H2 sensor was implemented. By using a 10 cm gas cell at atmospheric pressure, it was possible to detect concentrations from 0 to 20% with a sensitivity of 521 ppm and sub-minute time response. Moreover, the experimental measurements and simulated results have a high level of agreement. Finally, it is important to point out that, by using doped fiber with different characteristics, other wavelength emissions can be generated. Full article
(This article belongs to the Section Optics and Lasers)
Figures

Figure 1

Open AccessArticle
An On-Line Oxygen Forecasting System for Waterless Live Transportation of Flatfish Based on Feature Clustering
Appl. Sci. 2017, 7(9), 957; https://doi.org/10.3390/app7090957
Received: 31 July 2017 / Revised: 4 September 2017 / Accepted: 12 September 2017 / Published: 18 September 2017
Cited by 3 | Viewed by 1365 | PDF Full-text (4026 KB) | HTML Full-text | XML Full-text | Supplementary Files
Abstract
Accurate prediction of forthcoming oxygen concentration during waterless live fish transportation plays a key role in reducing the abnormal occurrence, increasing the survival rate in delivery operations, and optimizing manufacturing costs. The most effective ambient monitoring techniques that are based on the analysis [...] Read more.
Accurate prediction of forthcoming oxygen concentration during waterless live fish transportation plays a key role in reducing the abnormal occurrence, increasing the survival rate in delivery operations, and optimizing manufacturing costs. The most effective ambient monitoring techniques that are based on the analysis of historical process data when performing forecasting operations do not fully consider current ambient influence. This is likely lead to a greater deviation in on-line oxygen level forecasting in real situations. Therefore, it is not advisable for the system to perform early warning and on-line air adjustment in delivery. In this paper, we propose a hybrid method and its implementation system that combines a gray model (GM (1, 1)) with least squares support vector machines (LSSVM) that can be used effectively as a forecasting model to perform early warning effectively according to the dynamic changes of oxygen in a closed system. For accurately forecasting of the oxygen level, the fuzzy C-means clustering (FCM) algorithm was utilized for classification according to the flatfish’s physical features—i.e., length and weight—for more pertinent training. The performance of the gray model-particle swarm optimization-least squares support vector machines (GM-PSO-LSSVM) model was compared with the traditional modeling approaches of GM (1, 1) and LSSVM by applying it to predict on-line oxygen level, and the results showed that its predictions were more accurate than those of the LSSVM and grey model. Therefore, it is a suitable and effective method for abnormal condition forecasting and timely control in the waterless live transportation of flatfish. Full article
Figures

Figure 1

Open AccessFeature PaperReview
ECOAL Project—Delivering Solutions for Integrated Monitoring of Coal-Related Fires Supported on Optical Fiber Sensing Technology
Appl. Sci. 2017, 7(9), 956; https://doi.org/10.3390/app7090956
Received: 31 July 2017 / Revised: 12 September 2017 / Accepted: 13 September 2017 / Published: 16 September 2017
Viewed by 1662 | PDF Full-text (7175 KB) | HTML Full-text | XML Full-text
Abstract
The combustion of coal wastes resulting from mining is of particular environmental concern, and the importance of proper management involving real-time assessment of their status and identification of probable evolution scenarios is recognized. Continuous monitoring of the combustion temperature and emission levels of [...] Read more.
The combustion of coal wastes resulting from mining is of particular environmental concern, and the importance of proper management involving real-time assessment of their status and identification of probable evolution scenarios is recognized. Continuous monitoring of the combustion temperature and emission levels of certain gases allows for the possibility of planning corrective actions to minimize their negative impact on the surroundings. Optical fiber technology is well suited to this purpose and here we describe the main attributes and results obtained from a fiber optic sensing system projected to gather data on distributed temperature and gas emissions in these harsh environments. Full article
(This article belongs to the Special Issue Distributed Optical Fiber Sensors)
Figures

Figure 1

Open AccessFeature PaperArticle
CO2 with Mechanical Subcooling vs. CO2 Cascade Cycles for Medium Temperature Commercial Refrigeration Applications Thermodynamic Analysis
Appl. Sci. 2017, 7(9), 955; https://doi.org/10.3390/app7090955
Received: 24 July 2017 / Revised: 4 September 2017 / Accepted: 11 September 2017 / Published: 16 September 2017
Cited by 9 | Viewed by 2100 | PDF Full-text (6069 KB) | HTML Full-text | XML Full-text
Abstract
A recent trend to spread the use of CO2 refrigeration cycles in warm regions of the world is to combine a CO2 cycle with another one using a high performance refrigerant. Two alternatives are being considered: cascade and mechanical subcooling systems. [...] Read more.
A recent trend to spread the use of CO2 refrigeration cycles in warm regions of the world is to combine a CO2 cycle with another one using a high performance refrigerant. Two alternatives are being considered: cascade and mechanical subcooling systems. Both respond to a similar configuration of the refrigeration cycle, they being based on the use of two compressors and same number of heat exchangers. However, the compressor, heat exchanger sizes and energy performance differ a lot between them. This work, using experimental relations for CO2 and R1234yf semi-hermetic compressors analyzes in depth both alternatives under the warm climate of Spain. In general, it was concluded that the CO2 refrigeration solution with mechanical subcooling would cover all the conditions with high overall energy efficiency, thus it being recommended for further extension of the CO2 refrigeration applications. Full article
(This article belongs to the Section Mechanical Engineering)
Figures

Figure 1

Open AccessArticle
Computational Algorithms Underlying the Time-Based Detection of Sudden Cardiac Arrest via Electrocardiographic Markers
Appl. Sci. 2017, 7(9), 954; https://doi.org/10.3390/app7090954
Received: 17 August 2017 / Revised: 9 September 2017 / Accepted: 14 September 2017 / Published: 16 September 2017
Cited by 5 | Viewed by 3795 | PDF Full-text (7403 KB) | HTML Full-text | XML Full-text | Supplementary Files
Abstract
Early detection of sudden cardiac arrest (SCA) is critical to prevent serious repercussion such as irreversible neurological damage and death. Currently, the most effective method involves analyzing electrocardiogram (ECG) features obtained during ventricular fibrillation. In this study, data from 10 normal patients and [...] Read more.
Early detection of sudden cardiac arrest (SCA) is critical to prevent serious repercussion such as irreversible neurological damage and death. Currently, the most effective method involves analyzing electrocardiogram (ECG) features obtained during ventricular fibrillation. In this study, data from 10 normal patients and 10 SCA patients obtained from Physiobank were used to statistically compare features, such as heart rate, R-R interval duration, and heart rate variability (HRV) features from which the HRV features were then selected for classification via linear discriminant analysis (LDA) and linear and fine Gaussian support vector machines (SVM) in order to determine the ideal time-frame in which SCA can be accurately detected. The best accuracy was obtained at 2 and 8 min prior to SCA onset across all three classifiers. However, accuracy rates of 75–80% were also obtained at time-frames as early as 50 and 40 min prior to SCA onset. These results are clinically important in the field of SCA, as early detection improves overall patient survival. Full article
Figures

Figure 1

Open AccessArticle
Pt-Based Nanostructures for Observing Genuine SERS Spectra of p-Aminothiophenol (PATP) Molecules
Appl. Sci. 2017, 7(9), 953; https://doi.org/10.3390/app7090953
Received: 15 August 2017 / Revised: 9 September 2017 / Accepted: 9 September 2017 / Published: 15 September 2017
Viewed by 1377 | PDF Full-text (4234 KB) | HTML Full-text | XML Full-text | Supplementary Files
Abstract
By one-pot wet chemical method, Pt-based hollow nanostructures were synthesized at room temperature. Because of the highly damping optical response of the metal, these Pt-based hollow nanostructures exhibited weak thermal effects with a laser focal spot on 4-aminothiophenol (PATP) molecules limiting dimerisation. The [...] Read more.
By one-pot wet chemical method, Pt-based hollow nanostructures were synthesized at room temperature. Because of the highly damping optical response of the metal, these Pt-based hollow nanostructures exhibited weak thermal effects with a laser focal spot on 4-aminothiophenol (PATP) molecules limiting dimerisation. The isolated surface enhanced Raman scattering (SERS) spectra of PATP, in which the vibrational bands from 4,4′-dimercaptoazobenzene (DMAB) molecules are not observed, were able to be seen, and this was in good agreement with the Raman spectra of PATP powder. In addition, the concentration of PATP molecules was varied, and the illumination time was increased to 2000 s, respectively. It was found that spectra were stable with varied PATP concentrations, and the plasmon-driven chemical conversion of PATP to DMAB was still suppressed, even when the laser illumination time was increased to 2000 s. Full article
(This article belongs to the Special Issue Laser Interaction with Plasmonic Nanostructures)
Figures

Graphical abstract

Open AccessArticle
Study on the High Temperature Interfacial Stability of Ti/Mo/Yb0.3Co4Sb12 Thermoelectric Joints
Appl. Sci. 2017, 7(9), 952; https://doi.org/10.3390/app7090952
Received: 31 August 2017 / Revised: 12 September 2017 / Accepted: 13 September 2017 / Published: 15 September 2017
Cited by 4 | Viewed by 1223 | PDF Full-text (3840 KB) | HTML Full-text | XML Full-text
Abstract
To improve the interfacial stability at high temperatures, n-type skutterudite (SKD) thermoelectric joints with sandwich structures of Ti/Mo/Yb0.3Co4Sb12 were successfully designed and fabricated. In this structure, Mo and Ti were introduced as the barrier layer with the [...] Read more.
To improve the interfacial stability at high temperatures, n-type skutterudite (SKD) thermoelectric joints with sandwich structures of Ti/Mo/Yb0.3Co4Sb12 were successfully designed and fabricated. In this structure, Mo and Ti were introduced as the barrier layer with the goal of suppressing the interfacial diffusion and the buffer layer with the goal of enhancing the bonding strength, respectively. To evaluate the high temperature interfacial behavior of the Ti/Mo/Yb0.3Co4Sb12 joints, thermal shocking between 0 °C and 600 °C and isothermal aging at a temperature range of 550 °C to 650 °C were carried out in vacuum. During the isothermal aging process, Ti penetrates across the Mo layer, and finally diffuses into the Yb0.3Co4Sb12 matrix. By increasing the isothermal aging time, Ti continuously diffuses and reacts with the elements of Sb and Co in the matrix, consequently forming the multilayer-structured intermetallic compounds of Ti3Sb/Ti2Sb/TiCoSb. Diffusion kinetics was investigated and it was found that the interfacial evolution of the Ti/Mo/Yb0.3Co4Sb12 joints was a diffusion-controlling process. During the diffusion process, the formed Mo-Ti buffer layer acts as a damper, which greatly decelerates the diffusion of Ti towards the Yb0.3Co4Sb12 matrix at high temperatures. Meanwhile, it was found that the increase in the contact resistivity of the joints mainly derives from the inter-diffusion between Ti and Yb0.3Co4Sb12. As a result, the Ti/Mo/Yb0.3Co4Sb12 joint demonstrates the excellent stability of the interfacial contact resistivity. Service life prediction was made based on the stability of the contact resistivity, and it was found that the Ti/Mo/Yb0.3Co4Sb12 joint is qualified for practical applications at 550 °C. Full article
Figures

Graphical abstract

Open AccessArticle
Practical Challenge of Shredded Documents: Clustering of Chinese Homologous Pieces
Appl. Sci. 2017, 7(9), 951; https://doi.org/10.3390/app7090951
Received: 20 July 2017 / Revised: 7 September 2017 / Accepted: 12 September 2017 / Published: 15 September 2017
Viewed by 1136 | PDF Full-text (4657 KB) | HTML Full-text | XML Full-text | Supplementary Files
Abstract
When recovering a shredded document that has numerous mixed pieces, the difficulty of the recovery process can be reduced by clustering, which is a method of grouping pieces that originally belonged to the same page. Restoring homologous shredded documents (pieces from different pages [...] Read more.
When recovering a shredded document that has numerous mixed pieces, the difficulty of the recovery process can be reduced by clustering, which is a method of grouping pieces that originally belonged to the same page. Restoring homologous shredded documents (pieces from different pages of the same file) is a frequent problem, and because these pieces have nearly indistinguishable visual characteristics, grouping them is extremely difficult. Clustering research has important practical significance for document recovery because homologous pieces are ubiquitous. Because of the wide usage of Chinese and the huge demand for Chinese shredded document recovery, our research focuses on Chinese homologous pieces. In this paper, we propose a method of completely clustering Chinese homologous pieces in which the distribution features of the characters in the pieces and the document layout are used to correlate adjacent pieces and cluster them in different areas of a document. The experimental results show that the proposed method has a good clustering effect on real pieces. For the dataset containing 10 page documents (a total of 462 pieces), its average accuracy is 97.19%. Full article
Figures

Figure 1

Open AccessArticle
Decision Support Simulation Method for Process Improvement of Intermittent Production Systems
Appl. Sci. 2017, 7(9), 950; https://doi.org/10.3390/app7090950
Received: 20 August 2017 / Revised: 2 September 2017 / Accepted: 13 September 2017 / Published: 15 September 2017
Cited by 2 | Viewed by 1831 | PDF Full-text (2870 KB) | HTML Full-text | XML Full-text
Abstract
Nowadays production system processes are undergoing sweeping changes. The trends include an increase in the number of product variants to be produced, as well as the reduction of the production’s lead time. These trends were induced by new devices of the industry’s 4.0, [...] Read more.
Nowadays production system processes are undergoing sweeping changes. The trends include an increase in the number of product variants to be produced, as well as the reduction of the production’s lead time. These trends were induced by new devices of the industry’s 4.0, namely the Internet of Things and cyber physical systems. The companies have been applying intermittent production systems (job production, batch production) because of the increase in the number of product variants. Consequently, increasing the efficiency of these systems has become especially important. The aim of development in the long term—not achievable in many cases—is the realization of unique production, with mass production’s productivity and lower cost. The improvement of complex production systems can be realized efficiently only through simulation modeling. A standardized simulation method for intermittent production systems has not been elaborated so far. In this paper, I introduce a simulation method for system improvement and present its application possibilities and a practical example. Full article
(This article belongs to the Special Issue Modeling, Simulation, Operation and Control of Discrete Event Systems)
Figures

Figure 1

Open AccessArticle
Stochastic Investigation of Consolidation Process in Spatially Correlated Heterogeneous Soils
Appl. Sci. 2017, 7(9), 949; https://doi.org/10.3390/app7090949
Received: 22 August 2017 / Revised: 12 September 2017 / Accepted: 13 September 2017 / Published: 15 September 2017
Viewed by 1238 | PDF Full-text (3835 KB) | HTML Full-text | XML Full-text
Abstract
Soil consolidation as the dissipation of excess pore water pressure is mainly affected by the relative hydraulic conductivity among the layers. Geostatistical parameters such as the mean, the standard deviation, and the correlation length are physical indicators for each sedimentation and formation history. [...] Read more.
Soil consolidation as the dissipation of excess pore water pressure is mainly affected by the relative hydraulic conductivity among the layers. Geostatistical parameters such as the mean, the standard deviation, and the correlation length are physical indicators for each sedimentation and formation history. The effects of spatial variability on the excessive pore water pressure dissipation during consolidation process are investigated using numerical parametric studies, where multiple realizations are tested for selected hydraulic conductivity parameter using lognormal distribution. Numerical simulations show that the greater heterogeneity in hydraulic conductivity distribution applied, the longer time taken for the excess pore water pressure to dissipate, and the longer correlated variability encourages the greater variation in consolidation time. Such differences can be reduced significantly with the coupled drainage allowed by vertical drain method. Full article
Figures

Figure 1

Open AccessArticle
On the Optimisation of Practical Wireless Indoor and Outdoor Microcells Subject to QoS Constraints
Appl. Sci. 2017, 7(9), 948; https://doi.org/10.3390/app7090948
Received: 24 July 2017 / Revised: 25 August 2017 / Accepted: 13 September 2017 / Published: 15 September 2017
Cited by 1 | Viewed by 1092 | PDF Full-text (2279 KB) | HTML Full-text | XML Full-text
Abstract
Wireless indoor and outdoor microcells (WIOMs) have emerged as a promising means to deal with a high demand of mobile users for a variety of services. Over such heterogeneous networks, the deployment of WIOMs costs mobile/telecommunications company high capital expenditures and operating expenses. [...] Read more.
Wireless indoor and outdoor microcells (WIOMs) have emerged as a promising means to deal with a high demand of mobile users for a variety of services. Over such heterogeneous networks, the deployment of WIOMs costs mobile/telecommunications company high capital expenditures and operating expenses. This paper aims at optimising the WIOMs taking into account various network communication environments. We first develop an optimisation problem to minimise the number of cells as well as determining their optimal locations subject to the constraints of the coverage and quality-of-service (QoS) requirements. In particular, we propose a binary-search based cell positioning (BSCP) algorithm to find the optimal number of cells given a preset candidate antenna positions. The proposed BSCP algorithm is shown to not only reduce the number of cells for saving resources but also requires a low computational complexity compared to the conventional approaches with exhaustive search over all available sites. Moreover, EDX SignalPro is exploited as a simulation platform to verify the effectiveness of the proposed BSCP for the WIOMs with respect to various propagation modes and antenna parameters of different types, including isotropic, multiple-input single-output and multiple-input multiple-output. Full article
Figures

Figure 1

Open AccessArticle
Model-Based Design and Evaluation of a Brachiating Monkey Robot with an Active Waist
Appl. Sci. 2017, 7(9), 947; https://doi.org/10.3390/app7090947
Received: 4 July 2017 / Revised: 19 August 2017 / Accepted: 7 September 2017 / Published: 14 September 2017
Cited by 1 | Viewed by 1654 | PDF Full-text (6939 KB) | HTML Full-text | XML Full-text
Abstract
We report on the model-based development of a monkey robot that is capable of performing continuous brachiation locomotion on swingable rod, as the intermediate step toward studying brachiation on the soft rope or on horizontal ropes with both ends fixed. The work is [...] Read more.
We report on the model-based development of a monkey robot that is capable of performing continuous brachiation locomotion on swingable rod, as the intermediate step toward studying brachiation on the soft rope or on horizontal ropes with both ends fixed. The work is different from other previous works where the model or the robot swings on fixed bars. The model, which is composed of two rigid links, was inspired by the dynamic motion of primates. The model further served as the design guideline for a robot that has five degree of freedoms: two on each arm for rod changing and one on the waist to initiate a swing motion. The model was quantitatively formulated, and its dynamic behavior was analyzed in simulation. Further, a two-stage controller was developed within the simulation environment, where the first stage used the natural dynamics of a two-link pendulum-like model, and the second stage used the angular velocity feedback to regulate the waist motion. Finally, the robot was empirically built and evaluated. The experimental results confirm that the robot can perform model-like swing behavior and continuous brachiation locomotion on rods. Full article
(This article belongs to the Special Issue Bio-Inspired Robotics) Printed Edition available
Figures

Graphical abstract

Open AccessArticle
Synthetic Rock Analogue for Permeability Studies of Rock Salt with Mudstone
Appl. Sci. 2017, 7(9), 946; https://doi.org/10.3390/app7090946
Received: 28 July 2017 / Revised: 5 September 2017 / Accepted: 11 September 2017 / Published: 14 September 2017
Cited by 1 | Viewed by 2107 | PDF Full-text (6465 KB) | HTML Full-text | XML Full-text
Abstract
Knowledge about the permeability of surrounding rock (salt rock and mudstone interlayer) is an important topic, which acts as a key parameter to characterize the tightness of gas storage. The goal of experiments that test the permeability of gas storage facilities in rock [...] Read more.
Knowledge about the permeability of surrounding rock (salt rock and mudstone interlayer) is an important topic, which acts as a key parameter to characterize the tightness of gas storage. The goal of experiments that test the permeability of gas storage facilities in rock salt is to develop a synthetic analogue to use as a permeability model. To address the permeability of a mudstone/salt layered and mixed rock mass in Jintan, Jiangsu Province, synthetic mixed and layered specimens using the mudstone and the salt were fabricated for permeability testing. Because of the gas “slippage effect”, test results are corrected by the Klinkenberg method, and the permeability of specimens is obtained by regression fitting. The results show that the permeability of synthetic pure rock salt is 6.9 × 10−20 m2, and its porosity is 3.8%. The permeability of synthetic mudstone rock is 2.97 × 10−18 m2, with a porosity 17.8%. These results are close to those obtained from intact natural specimens. We also find that with the same mudstone content, the permeability of mixed specimens is about 40% higher than for the layered specimens, and with an increase in the mudstone content, the Klinkenberg permeability increases for both types of specimens. The permeability and mudstone content have a strong exponential relationship. When the mudstone content is below 40%, the permeability increases only slightly with mudstone content, whereas above this threshold, the permeability increases rapidly with mudstone content. The results of the study are of use in the assessment of the tightness of natural gas storage facilities in mudstone-rich rock salt formations in China. Full article
(This article belongs to the Special Issue Clean Energy and Fuel (Hydrogen) Storage)
Figures

Figure 1

Open AccessArticle
Study of the Direct Metal Deposition of AA2024 by ElectroSpark for Coating and Reparation Scopes
Appl. Sci. 2017, 7(9), 945; https://doi.org/10.3390/app7090945
Received: 20 July 2017 / Revised: 15 August 2017 / Accepted: 18 August 2017 / Published: 14 September 2017
Cited by 2 | Viewed by 1566 | PDF Full-text (9019 KB) | HTML Full-text | XML Full-text
Abstract
ElectroSpark Deposition (ESD) is a pulsed micro-welding process that is capable of depositing wear and corrosion resistance deposit to repair, improve, and to extend the service life of the components and tools. Major new applications have taken place in gas turbine blades and [...] Read more.
ElectroSpark Deposition (ESD) is a pulsed micro-welding process that is capable of depositing wear and corrosion resistance deposit to repair, improve, and to extend the service life of the components and tools. Major new applications have taken place in gas turbine blades and steam turbine blade protection and repair, and in military, medical, metal-working, and recreational equipment applications. In this study, the ESD technique was exploited to fabricate 2024 aluminum alloy deposit on a similar substrate. The deposits were deposited using different process parameters. Heat input was varied on three levels. The outcoming microstructure was analyzed by optical and scanning electron microscopies. The deposit was characterized by the overlapping of layers with a mixed microstructure. The average hardness was independent from the process parameters. Both porosity inside the deposits and cracks at the deposit/substrate interface were detected. The porosity lowered with the heat input and increased the average length of cracks. Full article
(This article belongs to the Section Materials)
Figures

Graphical abstract

Open AccessArticle
Characterization of Surface Ozone Behavior at Different Regimes
Appl. Sci. 2017, 7(9), 944; https://doi.org/10.3390/app7090944
Received: 25 July 2017 / Revised: 31 August 2017 / Accepted: 12 September 2017 / Published: 14 September 2017
Cited by 2 | Viewed by 1122 | PDF Full-text (1925 KB) | HTML Full-text | XML Full-text | Supplementary Files
Abstract
Previous studies showed that the influence of meteorological variables and concentrations of other air pollutants on O3 concentrations changes at different O3 concentration levels. In this study, threshold models with artificial neural networks (ANNs) were applied to characterize the O3 [...] Read more.
Previous studies showed that the influence of meteorological variables and concentrations of other air pollutants on O3 concentrations changes at different O3 concentration levels. In this study, threshold models with artificial neural networks (ANNs) were applied to characterize the O3 behavior at an urban site (Porto, Portugal), describing the effect of environmental and meteorological variables on O3 concentrations. ANN characteristics, and the threshold variable and value, were defined by genetic algorithms (GAs). The considered predictors were hourly average concentrations of NO, NO2, and O3, and meteorological variables (temperature, relative humidity, and wind speed) measured from January 2012 to December 2013. Seven simulations were performed and the achieved models considered wind speed (at 4.9 m·s−1), temperature (at 17.5 °C) and NO2 (at 26.6 μg·m−3) as the variables that determine the change of O3 behavior. All the achieved models presented a similar fitting performance: R2 = 0.71–0.72, RMSE = 14.5–14.7 μg·m−3, and the index of agreement of the second order of 0.91. The combined effect of these variables on O3 concentration was also analyzed. This statistical model was shown to be a powerful tool for interpreting O3 behavior, which is useful for defining policy strategies for human health protection concerning this air pollutant. Full article
Figures

Figure 1

Open AccessArticle
Coordinated Control of the Energy Router-Based Smart Home Energy Management System
Appl. Sci. 2017, 7(9), 943; https://doi.org/10.3390/app7090943
Received: 2 August 2017 / Revised: 3 September 2017 / Accepted: 12 September 2017 / Published: 13 September 2017
Cited by 2 | Viewed by 2754 | PDF Full-text (5032 KB) | HTML Full-text | XML Full-text
Abstract
Home area energy networks will be an essential part of the future Energy Internet in terms of energy saving, demand-side management and stability improvement of the distribution network, while an energy router will be the perfect choice to serve as an intelligent and [...] Read more.
Home area energy networks will be an essential part of the future Energy Internet in terms of energy saving, demand-side management and stability improvement of the distribution network, while an energy router will be the perfect choice to serve as an intelligent and multi-functional energy interface between the home area energy network and power grid. This paper elaborates on the design, analysis and implementation of coordinated control of the low-voltage energy router-based smart home energy management system (HEMS). The main contribution of this paper is to develop a novel solution to make the energy router technically feasible and practical for the HEMS to make full use of the renewable energy sources (RESs), while maintaining “operational friendly and beneficial” to the power grid. The behaviors of the energy router-based HEMS in correlation with the power grid are investigated, then the coordinated control scheme composed of a reference voltage and current compensation strategy and a fuzzy logic control-based power management strategy is developed. The system model is built on the MATLAB/Simulink platform, simulation results have demonstrated that the presented control scheme is a strong performer in making full use of the RES generations for the HEMS while maintaining the operational stability of the whole system, as well as in collaboration with the power grid to suppress the impact of RES output fluctuations and load consumption variations. Full article
(This article belongs to the Special Issue Smart Home and Energy Management Systems)
Figures

Figure 1

Open AccessArticle
Open Source 3-D Printed Nutating Mixer
Appl. Sci. 2017, 7(9), 942; https://doi.org/10.3390/app7090942
Received: 30 August 2017 / Revised: 11 September 2017 / Accepted: 11 September 2017 / Published: 13 September 2017
Cited by 4 | Viewed by 1390 | PDF Full-text (9254 KB) | HTML Full-text | XML Full-text | Supplementary Files
Abstract
As the open source development of additive manufacturing has led to low-cost desktop three-dimensional (3-D) printing, a number of scientists throughout the world have begun to share digital designs of free and open source scientific hardware. Open source scientific hardware enables custom experimentation, [...] Read more.
As the open source development of additive manufacturing has led to low-cost desktop three-dimensional (3-D) printing, a number of scientists throughout the world have begun to share digital designs of free and open source scientific hardware. Open source scientific hardware enables custom experimentation, laboratory control, rapid upgrading, transparent maintenance, and lower costs in general. To aid in this trend, this study describes the development, design, assembly, and operation of a 3-D printable open source desktop nutating mixer, which provides a fixed 20° platform tilt angle for a gentle three-dimensional (gyrating) agitation of chemical or biological samples (e.g., DNA or blood samples) without foam formation. The custom components for the nutating mixer are designed using open source FreeCAD software to enable customization. All of the non-readily available components can be fabricated with a low-cost RepRap 3-D printer using an open source software tool chain from common thermoplastics. All of the designs are open sourced and can be configured to add more functionality to the equipment in the future. It is relatively easy to assemble and is accessible to both the science education of younger students as well as state-of-the-art research laboratories. Overall, the open source nutating mixer can be fabricated with US$37 in parts, which is 1/10th of the cost of proprietary nutating mixers with similar capabilities. The open source nature of the device allow it to be easily repaired or upgraded with digital files, as well as to accommodate custom sample sizes and mixing velocities with minimal additional costs. Full article
(This article belongs to the Section Materials)
Figures

Graphical abstract

Open AccessArticle
A New Method for Analysing the Pressure Response Delay in a Pneumatic Brake System Caused by the Influence of Transmission Pipes
Appl. Sci. 2017, 7(9), 941; https://doi.org/10.3390/app7090941
Received: 29 July 2017 / Revised: 2 September 2017 / Accepted: 9 September 2017 / Published: 13 September 2017
Cited by 2 | Viewed by 2186 | PDF Full-text (3690 KB) | HTML Full-text | XML Full-text
Abstract
This study aims to propose an analysis method for resolving the pressure response of a pneumatic brake circuit considering the effect of a transmission pipe. Pneumatic brake systems (PBS) are widely used in commercial vehicles. The pressure response characteristic of the PBS is [...] Read more.
This study aims to propose an analysis method for resolving the pressure response of a pneumatic brake circuit considering the effect of a transmission pipe. Pneumatic brake systems (PBS) are widely used in commercial vehicles. The pressure response characteristic of the PBS is the key factor affecting braking performance. By using the thermodynamics of a variable-quality system, the pressure response model of the brake chamber is established, which includes the dynamic model of the pipe considering the unsteady friction and heat transfer. The partial-differential control equations of pipe are solved by introducing the constrained interpolation profile (CIP) method, and a virtual chamber model is proposed to set the boundary condition so as to solve the pressure response in the brake chamber simultaneously. Thus, the regularity of the brake pressure response is obtained by considering the influence of the pipe. Lastly, the model is verified experimentally. The present study indicates that the main factors that affect the pressure response delay are the pipe length and the combination forms of the sonic conductances of the orifices inlet and outlet. Furthermore, it helps to verify that the CIP method is an effective way of solving the pressure response of a brake circuit because of its high accuracy. The present study serves as a foundation for the design and analysis of a PBS. Full article
(This article belongs to the Special Issue Power Transmission and Control in Power and Vehicle Machineries)
Figures

Figure 1

Open AccessArticle
Competitive Evaluation of Planar Embedded Glass and Polymer Waveguides in Data Center Environments
Appl. Sci. 2017, 7(9), 940; https://doi.org/10.3390/app7090940
Received: 20 June 2017 / Revised: 31 August 2017 / Accepted: 1 September 2017 / Published: 13 September 2017
Cited by 1 | Viewed by 1476 | PDF Full-text (22234 KB) | HTML Full-text | XML Full-text
Abstract
Optical printed circuit board (OPCB) waveguide materials and fabrication methods have advanced considerably over the past 15 years, giving rise to two classes of embedded planar graded index waveguide based on polymer and glass. We consider the performance of these two emerging waveguide [...] Read more.
Optical printed circuit board (OPCB) waveguide materials and fabrication methods have advanced considerably over the past 15 years, giving rise to two classes of embedded planar graded index waveguide based on polymer and glass. We consider the performance of these two emerging waveguide classes in view of the anticipated deployment in data center environments of optical transceivers based on directly modulated multimode short wavelength VCSELs against those based on longer wavelength single-mode photonic integrated circuits. We describe the fabrication of graded index polymer waveguides, using the Mosquito and photo-addressing methods, and graded index glass waveguides, using ion diffusion on thin glass foils. A comparative characterization was carried out on the waveguide classes to show a clear reciprocal dependence of the performance of different waveguide classes on wavelength. Furthermore, the different waveguide types were connected into an optically disaggregated data switch and storage system to evaluate and validate their suitability for deployment in future data center environments. Full article
(This article belongs to the Special Issue Optical Interconnects)
Figures

Figure 1

Open AccessArticle
Structure and Capacitance of Electrical Double Layers at the Graphene–Ionic Liquid Interface
Appl. Sci. 2017, 7(9), 939; https://doi.org/10.3390/app7090939
Received: 25 August 2017 / Revised: 6 September 2017 / Accepted: 6 September 2017 / Published: 12 September 2017
Cited by 2 | Viewed by 2288 | PDF Full-text (3429 KB) | HTML Full-text | XML Full-text
Abstract
Molecular dynamics simulations are carried out to investigate the structure and capacitance of the electrical double layers (EDLs) at the interface of vertically oriented graphene and ionic liquids [EMIM]+/[BF4]. The distribution and migration of the ions in [...] Read more.
Molecular dynamics simulations are carried out to investigate the structure and capacitance of the electrical double layers (EDLs) at the interface of vertically oriented graphene and ionic liquids [EMIM]+/[BF4]. The distribution and migration of the ions in the EDL on the rough and non-rough electrode surfaces with different charge densities are compared and analyzed, and the effect of the electrode surface morphology on the capacitance of the EDL is clarified. The results suggest that alternate distributions of anions and cations in several consecutive layers are formed in the EDL on the electrode surface. When the electrode is charged, the layers of [BF4] anions experience more significant migration than those of [EMIM]+ cations. These ion layers can be extended deeper into the bulk electrolyte solution by the stronger interaction of the rough electrode, compared to those on the non-rough electrode surface. The potential energy valley of ions on the neutral electrode surface establishes a potential energy difference to compensate the energy cost of the ion accumulation, and is capable of producing a potential drop across the EDL on the uncharged electrode surface. Due to the greater effective contact area between the ions and electrode, the rough electrode possesses a larger capacitance than the non-rough one. In addition, it is harder for the larger-sized [EMIM]+ cations to accumulate in the narrow grooves on the rough electrode, when compared with the smaller [BF4]. Consequently, the double-hump-shaped C–V curve (which demonstrates the relationship between differential capacitance and potential drop across the EDL) for the rough electrode is asymmetric, where the capacitance increases more significantly when the electrode is positively charged. Full article
(This article belongs to the Special Issue Clean Energy and Fuel (Hydrogen) Storage)
Figures

Figure 1

Open AccessArticle
Ultralow Friction of ZrO2 Ball Sliding against DLC Films under Various Environments
Appl. Sci. 2017, 7(9), 938; https://doi.org/10.3390/app7090938
Received: 14 August 2017 / Revised: 4 September 2017 / Accepted: 5 September 2017 / Published: 12 September 2017
Cited by 5 | Viewed by 1618 | PDF Full-text (7464 KB) | HTML Full-text | XML Full-text
Abstract
Ultralow friction is achieved by ZrO2 as the friction mate material for DLC (Diamond like carbon) films under various environments. Coefficient of friction (CoF) of ZrO2/DLC films is as ultra low as 0.02 in ambient air at the temperature of [...] Read more.
Ultralow friction is achieved by ZrO2 as the friction mate material for DLC (Diamond like carbon) films under various environments. Coefficient of friction (CoF) of ZrO2/DLC films is as ultra low as 0.02 in ambient air at the temperature of 200 °C, and 0.03, 0.04 and 0.05 in hydrogen, nitrogen and vacuum environments at the temperature of 100 °C, respectively. It is concluded that the transferred films are formed on the worn surface of ZrO2 ball and amorphous carbon films. Ultralow friction of the friction pair is related with hydrogen, which is derived from DLC films, hydrogen environment or the liberation hydrogen due to hydrothermal oxidation. The ultralow friction mechanism is attributed to the formation of hydrogenated amorphous carbon films on ZrO2 ball and the shielding action of hydrogen from DLC films and the transferred films simultaneously. Full article
(This article belongs to the Section Mechanical Engineering)
Figures

Figure 1

Open AccessArticle
Weak Fault Feature Extraction Scheme for Intershaft Bearings Based on Linear Prediction and Order Tracking in the Rotation Speed Difference Domain
Appl. Sci. 2017, 7(9), 937; https://doi.org/10.3390/app7090937
Received: 7 August 2017 / Revised: 10 September 2017 / Accepted: 10 September 2017 / Published: 12 September 2017
Cited by 4 | Viewed by 1146 | PDF Full-text (6814 KB) | HTML Full-text | XML Full-text
Abstract
Because both the inner and outer rings rotate, the intershaft bearings used in gas turbines do not have fixed bearing housings. As a result, the vibration of intershaft bearings cannot be measured directly. Therefore, a vibration signal can only be collected through indirect [...] Read more.
Because both the inner and outer rings rotate, the intershaft bearings used in gas turbines do not have fixed bearing housings. As a result, the vibration of intershaft bearings cannot be measured directly. Therefore, a vibration signal can only be collected through indirect measurement. First, it must be transferred to adjacent bearings through the shafting. Then, it should be transferred by the elastic supports and complex structure of the thin-walled strut. The vibration signal is severely weakened during transmission under the influences of the transfer path. In the meantime, in the vibration of other components, a huge amount of noise is produced by the air flow, and the variable speeds of the inner and outer rings of the intershaft bearings make it harder to analyze the signal. Hence, it is very difficult to extract the vibration fault features of intershaft bearings. To deal with the variable speed of dual rotors, as well as the weak signal, a fault feature extraction scheme for the weak fault signals of intershaft bearings is proposed in this paper. This scheme is based on linear prediction, spectral kurtosis, and order tracking in the rotation speed difference domain. First, a prewhitening process, based on linear prediction, is applied to the fault signal of the intershaft bearings to eliminate the stationary component. Thus, the remaining components, including the impulse signal of faulty bearings and nonstationary noise, can retain the features of the vibrational bearings, in addition to reducing the noise. Second, the optimal center frequency and bandwidth of the band-pass filter, applied to resonant demodulation, are selected by spectral kurtosis. Subsequently, the enveloped signal containing the features of the faults found in the intershaft bearings is obtained by resonance demodulation. The quasi-stationary signal in the angle domain is acquired by the even angle resampling of the nonstationary envelope signal, as a result of the variable speed. The final order spectrum is obtained through a Fourier transform. Fault diagnosis can be conducted for the intershaft bearings by comparing this spectrum with the feature order of the bearing fault. Experiments were conducted to verify the validity of the proposed scheme. Full article
(This article belongs to the Section Mechanical Engineering)
Figures

Figure 1

Open AccessArticle
Localization in Low Power Wide Area Networks Using Wi-Fi Fingerprints
Appl. Sci. 2017, 7(9), 936; https://doi.org/10.3390/app7090936
Received: 13 July 2017 / Revised: 2 September 2017 / Accepted: 7 September 2017 / Published: 12 September 2017
Cited by 4 | Viewed by 1451 | PDF Full-text (835 KB) | HTML Full-text | XML Full-text | Supplementary Files
Abstract
Supply chain management requires regular updates of the location of assets, which can be enabled by low power wide area networks, such as Sigfox. While it is useful to localize a device simply by its communication signals, this is very difficult to do [...] Read more.
Supply chain management requires regular updates of the location of assets, which can be enabled by low power wide area networks, such as Sigfox. While it is useful to localize a device simply by its communication signals, this is very difficult to do with Sigfox because of wide area and ultra narrowband nature. On the other hand, installing a satellite localization element on the device greatly increases its power consumption. We investigated using information about nearby Wi-Fi access points as a way to localize the asset over the Sigfox network, so without connecting to those Wi-Fi networks. This paper reports the location error that can be achieved by this type of outdoor localization. By using a combination of two databases, we could localize the device on all 36 test locations with a median location error of 39 m . This shows that the localization accuracy of this method is promising enough to warrant further study, most specifically the minimal power consumption. Full article
(This article belongs to the Special Issue Advanced Internet of Things for Smart Infrastructure System)
Figures

Figure 1

Open AccessArticle
Measurement Matrix Analysis and Radiation Improvement of a Metamaterial Aperture Antenna for Coherent Computational Imaging
Appl. Sci. 2017, 7(9), 933; https://doi.org/10.3390/app7090933
Received: 26 July 2017 / Revised: 18 August 2017 / Accepted: 7 September 2017 / Published: 12 September 2017
Cited by 4 | Viewed by 1704 | PDF Full-text (14386 KB) | HTML Full-text | XML Full-text
Abstract
A metamaterial aperture antenna (MAA) that generates frequency-diverse radiation field patterns has been introduced in the context of microwave wave imaging to perform compressive image reconstruction. This paper presents a new metamateriapl aperture design, which includes two kinds of metamaterial elements with random [...] Read more.
A metamaterial aperture antenna (MAA) that generates frequency-diverse radiation field patterns has been introduced in the context of microwave wave imaging to perform compressive image reconstruction. This paper presents a new metamateriapl aperture design, which includes two kinds of metamaterial elements with random distribution. One is a high-Q resonant element whose resonant frequency is agile, and the other one is a low-Q element that has a high radiation efficiency across frequency band. Numerical simulations and measurements show that the radiation efficiency of up to 60% can be achieved for the MAA and the far-field patterns owns good orthogonality, when using the complementary electric-field-coupled (CELC) element and the complementary Jerusalem cross (CJC) element with a random distribution ratio of 4 to 1, which could be effectively used to reconstruct the target scattering scene. Full article
(This article belongs to the Special Issue Metasurfaces: Physics and Applications) Printed Edition available
Figures

Figure 1

Open AccessArticle
LiDARgrammetry: A New Method for Generating Synthetic Stereoscopic Products from Digital Elevation Models
Appl. Sci. 2017, 7(9), 906; https://doi.org/10.3390/app7090906
Received: 16 May 2017 / Revised: 10 August 2017 / Accepted: 4 September 2017 / Published: 12 September 2017
Cited by 2 | Viewed by 1678 | PDF Full-text (10102 KB) | HTML Full-text | XML Full-text
Abstract
There are currently several new technologies being used to generate digital elevation models that do not use photogrammetric techniques. For example, LiDAR (Laser Imaging Detection and Ranging) and RADAR (RAdio Detection And Ranging) can generate 3D points and reflectivity information of the surface [...] Read more.
There are currently several new technologies being used to generate digital elevation models that do not use photogrammetric techniques. For example, LiDAR (Laser Imaging Detection and Ranging) and RADAR (RAdio Detection And Ranging) can generate 3D points and reflectivity information of the surface without using a photogrammetric approach. In the case of LiDAR, the intensity level indicates the amount of energy that the object reflects after a laser pulse is transmitted. This energy mainly depends on the material and the wavelength used by LiDAR. This intensity level can be used to generate a synthetic image colored by this attribute (intensity level), which can be viewed as a RGB (red, green and blue) picture. This work presents the outline of an innovative method, designed by the authors, to generate synthetic pictures from point clouds to use in classical photogrammetric software (digital restitution or stereoscopic vision). This is conducted using available additional information (for example, the intensity level of LiDAR). This allows mapping operators to view the LiDAR as if it were stereo-imagery, so they can manually digitize points, 3D lines, break lines, polygons and so on. Full article
(This article belongs to the Special Issue Laser Scanning)
Figures

Figure 1

Open AccessArticle
Analysis of the Pyroclastic Flow Deposits of Mount Sinabung and Merapi Using Landsat Imagery and the Artificial Neural Networks Approach
Appl. Sci. 2017, 7(9), 935; https://doi.org/10.3390/app7090935
Received: 25 July 2017 / Revised: 7 September 2017 / Accepted: 8 September 2017 / Published: 11 September 2017
Cited by 2 | Viewed by 1605 | PDF Full-text (12161 KB) | HTML Full-text | XML Full-text
Abstract
Volcanic eruptions cause pyroclastic flows, which can destroy plantations and settlements. We used image data from Landsat 7 Bands 7, 4 and 2 and Landsat 8 Bands 7, 5 and 3 to observe and analyze the distribution of pyroclastic flow deposits for two [...] Read more.
Volcanic eruptions cause pyroclastic flows, which can destroy plantations and settlements. We used image data from Landsat 7 Bands 7, 4 and 2 and Landsat 8 Bands 7, 5 and 3 to observe and analyze the distribution of pyroclastic flow deposits for two volcanos, Mount Sinabung and Merapi, over a period of 10 years (2001–2017). The satellite data are used in conjunction with an artificial neural network method to produce maps of pyroclastic precipitation for Landsat 7 and 8, then we calculated the pyroclastic precipitation area using an artificial neural network method after dividing the images into four classes based on color. Red, green, blue and yellow were used to indicate pyroclastic deposits, vegetation and forest, water and cloud, and farmland, respectively. The area affected by a volcanic eruption was deduced from the neural network processing, including calculating the area of pyroclastic deposits. The main differences between the pyroclastic flow deposits of Mount Sinabung and Mount Merapi are: the sediment deposits of the pyroclastic flows of Mount Sinabung tend to widen, whereas those of Merapi elongated; the direction of pyroclastic flow differed; and the area affected by an eruption was greater for Mount Merapi than Mount Sinabung because the VEI (Volcanic Explosivity Index) during the last 10 years of Mount Merapi was larger than Mount Sinabung. Full article
Figures

Figure 1

Appl. Sci. EISSN 2076-3417 Published by MDPI AG, Basel, Switzerland RSS E-Mail Table of Contents Alert
Back to Top