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Electronics, Volume 5, Issue 4 (December 2016)

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Open AccessArticle 3D Environment Mapping Using the Kinect V2 and Path Planning Based on RRT Algorithms
Electronics 2016, 5(4), 70; doi:10.3390/electronics5040070
Received: 19 August 2016 / Revised: 21 September 2016 / Accepted: 26 September 2016 / Published: 18 October 2016
Cited by 2 | PDF Full-text (6172 KB) | HTML Full-text | XML Full-text
Abstract
This paper describes a 3D path planning system that is able to provide a solution trajectory for the automatic control of a robot. The proposed system uses a point cloud obtained from the robot workspace, with a Kinect V2 sensor to identify the
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This paper describes a 3D path planning system that is able to provide a solution trajectory for the automatic control of a robot. The proposed system uses a point cloud obtained from the robot workspace, with a Kinect V2 sensor to identify the interest regions and the obstacles of the environment. Our proposal includes a collision-free path planner based on the Rapidly-exploring Random Trees variant (RRT*), for a safe and optimal navigation of robots in 3D spaces. Results on RGB-D segmentation and recognition, point cloud processing, and comparisons between different RRT* algorithms, are presented. Full article
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Open AccessArticle Optical Orientation and Inverse Spin Hall Effect as Effective Tools to Investigate Spin-Dependent Diffusion
Electronics 2016, 5(4), 80; doi:10.3390/electronics5040080
Received: 1 October 2016 / Revised: 15 November 2016 / Accepted: 17 November 2016 / Published: 22 November 2016
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Abstract
In this work we address optical orientation, a process consisting in the excitation of spin polarized electrons across the gap of a semiconductor. We show that the combination of optical orientation with spin-dependent scattering leading to the inverse spin-Hall effect, i.e., to the
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In this work we address optical orientation, a process consisting in the excitation of spin polarized electrons across the gap of a semiconductor. We show that the combination of optical orientation with spin-dependent scattering leading to the inverse spin-Hall effect, i.e., to the conversion of a spin current into an electrical signal, represents a powerful tool to generate and detect spin currents in solids. We consider a few examples where these two phenomena together allow addressing the spin-dependent transport properties across homogeneous samples or metal/semiconductor Schottky junctions. Full article
(This article belongs to the Special Issue Spin Optoelectronics)
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Open AccessArticle Characterizing Energy per Job in Cloud Applications
Electronics 2016, 5(4), 90; doi:10.3390/electronics5040090
Received: 31 July 2016 / Revised: 28 November 2016 / Accepted: 2 December 2016 / Published: 12 December 2016
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Abstract
Energy efficiency is a major research focus in sustainable development and is becoming even more critical in information technology (IT) with the introduction of new technologies, such as cloud computing and big data, that attract more business users and generate more data to
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Energy efficiency is a major research focus in sustainable development and is becoming even more critical in information technology (IT) with the introduction of new technologies, such as cloud computing and big data, that attract more business users and generate more data to be processed. While many proposals have been presented to optimize power consumption at a system level, the increasing heterogeneity of current workloads requires a finer analysis in the application level to enable adaptive behaviors and in order to reduce the global energy usage. In this work, we focus on batch applications running on virtual machines in the context of data centers. We analyze the application characteristics, model their energy consumption and quantify the energy per job. The analysis focuses on evaluating the efficiency of applications in terms of performance and energy consumed per job, in particular when shared resources are used and the hosts on which the virtual machines are running are heterogeneous in terms of energy profiles, with the aim of identifying the best combinations in the use of resources. Full article
(This article belongs to the Special Issue Energy Saving in Data Centers)
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Open AccessArticle Modelling and Daisy Chaining Control Allocation of a Multirotor Helicopter with a Single Tilting Rotor
Electronics 2016, 5(4), 81; doi:10.3390/electronics5040081
Received: 7 October 2016 / Revised: 7 November 2016 / Accepted: 15 November 2016 / Published: 23 November 2016
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Abstract
This paper presents the development and implementation of a single tilting rotor multirotor helicopter. A single tilting rotor multirotor helicopter is proposed that allows for decoupled lateral acceleration and attitude states. A dynamics model of the proposed multirotor helicopter is established to enable
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This paper presents the development and implementation of a single tilting rotor multirotor helicopter. A single tilting rotor multirotor helicopter is proposed that allows for decoupled lateral acceleration and attitude states. A dynamics model of the proposed multirotor helicopter is established to enable control system development. A control system architecture and daisy chaining-based control allocation scheme is developed and implemented. The control architecture facilitates the control of decoupled lateral accelerations and attitudes. Further, a computational and experimental analysis is undertaken and offers evidence that the proposed multirotor helicopter and control system architecture enables the multirotor helicopter to achieve lateral accelerations without requiring attitude actuation. Full article
(This article belongs to the Special Issue Unmanned Aerial Systems/Vehicles (UAS/V) and Drones)
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Open AccessArticle Energetic Stabilities, Structural and Electronic Properties of Monolayer Graphene Doped with Boron and Nitrogen Atoms
Electronics 2016, 5(4), 91; doi:10.3390/electronics5040091
Received: 6 November 2016 / Revised: 23 November 2016 / Accepted: 6 December 2016 / Published: 14 December 2016
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Abstract
The structural, energetic, and electronic properties of single-layer graphene doped with boron and nitrogen atoms with varying doping concentrations and configurations have been investigated here via first-principles density functional theory calculations. It was found that the band gap increases with an increase in
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The structural, energetic, and electronic properties of single-layer graphene doped with boron and nitrogen atoms with varying doping concentrations and configurations have been investigated here via first-principles density functional theory calculations. It was found that the band gap increases with an increase in doping concentration, whereas the energetic stability of the doped systems decreases with an increase in doping concentration. It was observed that both the band gaps and the cohesive energies also depend on the atomic configurations considered for the substitutional dopants. Stability was found to be higher in N-doped graphene systems as compared to B-doped graphene systems. The electronic structures of B- and N-doped graphene systems were also found to be strongly influenced by the positioning of the dopant atoms in the graphene lattice. The systems with dopant atoms at alternate sublattices have been found to have the lowest cohesive energies and therefore form the most stable structures. These results indicate an ability to adjust the band gap as required using B and N atoms according to the choice of the supercell, i.e., the doping density and substitutional dopant sites, which could be useful in the design of graphene-based electronic and optical devices. Full article
(This article belongs to the Special Issue Two-Dimensional Electronics and Optoelectronics)
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Open AccessArticle A Raspberry Pi Cluster Instrumented for Fine-Grained Power Measurement
Electronics 2016, 5(4), 61; doi:10.3390/electronics5040061
Received: 30 April 2016 / Revised: 9 September 2016 / Accepted: 13 September 2016 / Published: 23 September 2016
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Abstract
Power consumption has become an increasingly important metric when building large supercomputing clusters. One way to reduce power usage in large clusters is to use low-power embedded processors rather than the more typical high-end server CPUs (central processing units). We investigate various power-related
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Power consumption has become an increasingly important metric when building large supercomputing clusters. One way to reduce power usage in large clusters is to use low-power embedded processors rather than the more typical high-end server CPUs (central processing units). We investigate various power-related metrics for seventeen different embedded ARM development boards in order to judge the appropriateness of using them in a computing cluster. We then build a custom cluster out of Raspberry Pi boards, which is specially designed for per-node detailed power measurement. In addition to serving as an embedded cluster testbed, our cluster’s power measurement, visualization and thermal features make it an excellent low-cost platform for education and experimentation. Full article
(This article belongs to the Special Issue Raspberry Pi Technology)
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Open AccessArticle Scheduling Energy Efficient Data Centers Using Renewable Energy
Electronics 2016, 5(4), 71; doi:10.3390/electronics5040071
Received: 15 August 2016 / Revised: 30 September 2016 / Accepted: 12 October 2016 / Published: 19 October 2016
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Abstract
This work presents a multi-objective approach for scheduling energy consumption in data centers considering traditional and green energy data sources. This problem is addressed as a whole by simultaneously scheduling the state of the servers and the cooling devices, and by scheduling the
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This work presents a multi-objective approach for scheduling energy consumption in data centers considering traditional and green energy data sources. This problem is addressed as a whole by simultaneously scheduling the state of the servers and the cooling devices, and by scheduling the workload of the data center, which is comprised of a set of independent tasks with due dates. Its goal is to simultaneously minimize the energy consumption budget of the data center, the energy consumption deviation from a reference profile, and the amount of tasks whose due dates are violated. Two multi-objective evolutionary algorithms hybridized with a greedy heuristic are proposed and are enhanced by applying simulated annealing for post hoc optimization. Experimental results show that these methods are able to reduce energy consumption budget by about 60% while adequately following a power consumption profile and providing a high quality of service. These results confirm the effectiveness of the proposed algorithmic approach and the usefulness of green energy sources for data center infrastructures. Full article
(This article belongs to the Special Issue Energy Saving in Data Centers)
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Open AccessArticle Gaussian Mixture Modeling for Detecting Integrity Attacks in Smart Grids
Electronics 2016, 5(4), 82; doi:10.3390/electronics5040082
Received: 17 September 2016 / Revised: 2 November 2016 / Accepted: 15 November 2016 / Published: 23 November 2016
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Abstract
The thematics focusing on inserting intelligence in cyber-physical critical infrastructures (CI) have been receiving a lot of attention in the recent years. This paper presents a methodology able to differentiate between the normal state of a system composed of interdependent infrastructures and states
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The thematics focusing on inserting intelligence in cyber-physical critical infrastructures (CI) have been receiving a lot of attention in the recent years. This paper presents a methodology able to differentiate between the normal state of a system composed of interdependent infrastructures and states that appear to be normal but the system (or parts of it) has been compromised. The system under attack seems to operate properly since the associated measurements are simply a variation of the normal ones created by the attacker, and intended to mislead the operator while the consequences may be of catastrophic nature. Here, we propose a holistic modeling scheme based on Gaussian mixture models estimating the probability density function of the parameters coming from linear time invariant (LTI) models. LTI models are approximating the relationships between the datastreams coming from the CI. The experimental platform includes a power grid simulator of the IEEE 30 bus model controlled by a cyber network platform. Subsequently, we implemented a wide range of integrity attacks (replay, ramp, pulse, scaling, and random) with different intensity levels. An extensive experimental campaign was designed and we report satisfying detection results. Full article
(This article belongs to the Special Issue Smart Grid Cyber Security)
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Open AccessArticle Automatic Measurement of Chew Count and Chewing Rate during Food Intake
Electronics 2016, 5(4), 62; doi:10.3390/electronics5040062
Received: 19 July 2016 / Revised: 31 August 2016 / Accepted: 8 September 2016 / Published: 23 September 2016
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Abstract
Research suggests that there might be a relationship between chew count as well as chewing rate and energy intake. Chewing has been used in wearable sensor systems for the automatic detection of food intake, but little work has been reported on the automatic
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Research suggests that there might be a relationship between chew count as well as chewing rate and energy intake. Chewing has been used in wearable sensor systems for the automatic detection of food intake, but little work has been reported on the automatic measurement of chew count or chewing rate. This work presents a method for the automatic quantification of chewing episodes captured by a piezoelectric sensor system. The proposed method was tested on 120 meals from 30 participants using two approaches. In a semi-automatic approach, histogram-based peak detection was used to count the number of chews in manually annotated chewing segments, resulting in a mean absolute error of 10.40 % ± 7.03%. In a fully automatic approach, automatic food intake recognition preceded the application of the chew counting algorithm. The sensor signal was divided into 5-s non-overlapping epochs. Leave-one-out cross-validation was used to train a artificial neural network (ANN) to classify epochs as “food intake” or “no intake” with an average F1 score of 91.09%. Chews were counted in epochs classified as food intake with a mean absolute error of 15.01% ± 11.06%. The proposed methods were compared with manual chew counts using an analysis of variance (ANOVA), which showed no statistically significant difference between the two methods. Results suggest that the proposed method can provide objective and automatic quantification of eating behavior in terms of chew counts and chewing rates. Full article
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Open AccessArticle Low Power High-Efficiency Shift Register Using Implicit Pulse-Triggered Flip-Flop in 130 nm CMOS Process for a Cryptographic RFID Tag
Electronics 2016, 5(4), 92; doi:10.3390/electronics5040092
Received: 30 September 2016 / Revised: 20 November 2016 / Accepted: 28 November 2016 / Published: 16 December 2016
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Abstract
The shift register is a type of sequential logic circuit which is mostly used for storing digital data or the transferring of data in the form of binary numbers in radio frequency identification (RFID) applications to improve the security of the system. A
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The shift register is a type of sequential logic circuit which is mostly used for storing digital data or the transferring of data in the form of binary numbers in radio frequency identification (RFID) applications to improve the security of the system. A power-efficient shift register utilizing a new flip-flop with an implicit pulse-triggered structure is presented in this article. The proposed flip-flop has features of high performance and low power. It is composed of a sampling circuit implemented by five transistors, a C-element for rise and fall paths, and a keeper stage. The speed is enhanced by executing four clocked transistors together with a transition condition technique. The simulation result confirms that the proposed topology consumes the lowest amounts of power of 30.1997 and 22.7071 nW for parallel in –parallel out (PIPO) and serial in –serial out (SISO) shift register respectively covering 22 µm2 chip area. The overall design consist of only 16 transistors and is simulated in 130 nm complementary-metal-oxide-semiconductor (CMOS) technology with a 1.2 V power supply. Full article
(This article belongs to the Special Issue RFID Systems and Applications)
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Open AccessArticle AgPi: Agents on Raspberry Pi
Electronics 2016, 5(4), 72; doi:10.3390/electronics5040072
Received: 4 June 2016 / Revised: 23 August 2016 / Accepted: 30 September 2016 / Published: 19 October 2016
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Abstract
The Raspberry Pi and its variants have brought with them an aura of change in the world of embedded systems. With their impressive computation and communication capabilities and low footprint, these devices have thrown open the possibility of realizing a network of things
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The Raspberry Pi and its variants have brought with them an aura of change in the world of embedded systems. With their impressive computation and communication capabilities and low footprint, these devices have thrown open the possibility of realizing a network of things in a very cost-effective manner. While such networks offer good solutions to prominent issues, they are indeed a long way from being smart or intelligent. Most of the currently available implementations of such a network of devices involve a centralized cloud-based server that contributes to making the necessary intelligent decisions, leaving these devices fairly underutilized. Though this paradigm provides for an easy and rapid solution, they have limited scalability, are less robust and at times prove to be expensive. In this paper, we introduce the concept of Agents on Raspberry Pi (AgPi) as a cyber solution to enhance the smartness and flexibility of such embedded networks of physical devices in a decentralized manner. The use of a Multi-Agent System (MAS) running on Raspberry Pis aids agents, both static and mobile, to govern the various activities within the network. Agents can act autonomously or on behalf of a human user and can collaborate, learn, adapt and act, thus contributing to embedded intelligence. This paper describes how Tartarus, a multi-agent platform, embedded on Raspberry Pis that constitute a network, can bring the best out of the system. To reveal the versatility of the concept of AgPi, an application for a Location-Aware and Tracking Service (LATS) is presented. The results obtained from a comparison of data transfer cost between the conventional cloud-based approach with AgPi have also been included. Full article
(This article belongs to the Special Issue Raspberry Pi Technology)
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Open AccessArticle Modeling and Design of a New Flexible Graphene-on-Silicon Schottky Junction Solar Cell
Electronics 2016, 5(4), 73; doi:10.3390/electronics5040073
Received: 5 September 2016 / Revised: 3 October 2016 / Accepted: 19 October 2016 / Published: 26 October 2016
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Abstract
A new graphene-based flexible solar cell with a power conversion efficiency >10% has been designed. The environmental stability and the low complexity of the fabrication process are the two main advantages of the proposed device with respect to other flexible solar cells. The
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A new graphene-based flexible solar cell with a power conversion efficiency >10% has been designed. The environmental stability and the low complexity of the fabrication process are the two main advantages of the proposed device with respect to other flexible solar cells. The designed solar cell is a graphene/silicon Schottky junction whose performance has been enhanced by a graphene oxide layer deposited on the graphene sheet. The effect of the graphene oxide is to dope the graphene and to act as anti-reflection coating. A silicon dioxide ultrathin layer interposed between the n-Si and the graphene increases the open-circuit voltage of the cell. The solar cell optimization has been achieved through a mathematical model, which has been validated by using experimental data reported in literature. The new flexible photovoltaic device can be integrated in a wide range of microsystems powered by solar energy. Full article
(This article belongs to the Special Issue Two-Dimensional Electronics and Optoelectronics)
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Open AccessArticle A Wearable System for the Evaluation of the Human-Horse Interaction: A Preliminary Study
Electronics 2016, 5(4), 63; doi:10.3390/electronics5040063
Received: 26 June 2016 / Revised: 14 September 2016 / Accepted: 18 September 2016 / Published: 26 September 2016
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Abstract
This study reports on a preliminary estimation of the human-horse interaction through the analysis of the heart rate variability (HRV) in both human and animal by using the dynamic time warping (DTW) algorithm. Here, we present a wearable system for HRV monitoring in
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This study reports on a preliminary estimation of the human-horse interaction through the analysis of the heart rate variability (HRV) in both human and animal by using the dynamic time warping (DTW) algorithm. Here, we present a wearable system for HRV monitoring in horses. Specifically, we first present a validation of a wearable electrocardiographic (ECG) monitoring system for horses in terms of comfort and robustness, then we introduce a preliminary objective estimation of the human-horse interaction. The performance of the proposed wearable system for horses was compared with a standard system in terms of movement artifact (MA) percentage. Seven healthy horses were monitored without any movement constraints. As a result, the lower amount of MA% of the wearable system suggests that it could be profitably used for reliable measurement of physiological parameters related to the autonomic nervous system (ANS) activity in horses, such as the HRV. Human-horse interaction estimation was achieved through the analysis of their HRV time series. Specifically, DTW was applied to estimate dynamic coupling between human and horse in a group of fourteen human subjects and one horse. Moreover, a support vector machine (SVM) classifier was able to recognize the three classes of interaction with an accuracy greater than 78%. Preliminary significant results showed the discrimination of three distinct real human-animal interaction levels. These results open the measurement and characterization of the already empirically-proven relationship between human and horse. Full article
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Open AccessArticle Stability Analysis of Quantum-Dot Spin-VCSELs
Electronics 2016, 5(4), 83; doi:10.3390/electronics5040083
Received: 20 October 2016 / Revised: 15 November 2016 / Accepted: 18 November 2016 / Published: 23 November 2016
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Abstract
Spin-polarized vertical-cavity surface-emitting lasers (spin-VCSELs) and vertical external-cavity surface-emitting lasers (spin-VECSELs) are of interest since their output polarization can be manipulated by spin-selective pumping, either optical or electrical. These devices, using quantum dot (QD) material for the active region, have shown instability (periodic
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Spin-polarized vertical-cavity surface-emitting lasers (spin-VCSELs) and vertical external-cavity surface-emitting lasers (spin-VECSELs) are of interest since their output polarization can be manipulated by spin-selective pumping, either optical or electrical. These devices, using quantum dot (QD) material for the active region, have shown instability (periodic oscillations) and polarization switching in previous theoretical simulations based on a rate equation model. It has been recognized that the polarization switching occurs between two possible sets of solutions, termed here in-phase and out-of-phase. The present contribution seeks to give enhanced understanding of these behaviors by applying a stability analysis to the system of equations used for such simulations. The results indicate that the choice of in-phase and out-of-phase solutions that appear in a time-dependent simulation is determined by the condition that the corresponding steady-state solutions are stable against small perturbations. The stability analysis is shown to be a valuable theoretical tool for future study of spin-V(E)SELs in the context of understanding and guiding future experimental research. Full article
(This article belongs to the Special Issue Spin Optoelectronics)
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Open AccessArticle A New Power Quality Instrument Based on Raspberry-Pi
Electronics 2016, 5(4), 64; doi:10.3390/electronics5040064
Received: 30 June 2016 / Revised: 14 September 2016 / Accepted: 19 September 2016 / Published: 27 September 2016
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Abstract
This article describes a new instrument for power quality (PQ) measurements based on the Raspberry-Pi. This is the latest step of a long study started by the Electric and Electronic Measurements Laboratory of “Roma Tre” University 12 years ago. During this time, the
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This article describes a new instrument for power quality (PQ) measurements based on the Raspberry-Pi. This is the latest step of a long study started by the Electric and Electronic Measurements Laboratory of “Roma Tre” University 12 years ago. During this time, the Laboratory developed and refined instrumentation for high accuracy power quality measurements. Through its own architecture, the new instrument allows the use of the Raspberry instead of a personal computer (PC). The data acquired and locally processed are then sent to a remote server where they can be shown to users. Imagines of the system and of the data prove the activity of the system. Full article
(This article belongs to the Special Issue Raspberry Pi Technology)
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Open AccessArticle On the Application of the Raspberry Pi as an Advanced Acoustic Sensor Network for Noise Monitoring
Electronics 2016, 5(4), 74; doi:10.3390/electronics5040074
Received: 12 July 2016 / Revised: 6 October 2016 / Accepted: 20 October 2016 / Published: 27 October 2016
Cited by 1 | PDF Full-text (5028 KB) | HTML Full-text | XML Full-text
Abstract
The concept of Smart Cities and the monitoring of environmental parameters is an area of research that has attracted scientific attention during the last decade. These environmental parameters are well-known as important factors in their affection towards people. Massive monitoring of this kind
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The concept of Smart Cities and the monitoring of environmental parameters is an area of research that has attracted scientific attention during the last decade. These environmental parameters are well-known as important factors in their affection towards people. Massive monitoring of this kind of parameters in cities is an expensive and complex task. Recent technologies of low-cost computing and low-power devices have opened researchers to a wide and more accessible research field, developing monitoring devices for deploying Wireless Sensor Networks. Gathering information from them, improved urban plans could be carried out and the information could help citizens. In this work, the prototyping of a low-cost acoustic sensor based on the Raspberry Pi platform for its use in the analysis of the sound field is described. The device is also connected to the cloud to share results in real time. The computation resources of the Raspberry Pi allow treating high quality audio for calculating acoustic parameters. A pilot test was carried out with the installation of two acoustic devices in the refurbishment works of a neighbourhood. In this deployment, the evaluation of these devices through long-term measurements was carried out, obtaining several acoustic parameters in real time for its broadcasting and study. This test has shown the Raspberry Pi as a powerful and affordable computing core of a low-cost device, but also the pilot test has served as a query tool for the inhabitants of the neighbourhood to be more aware about the noise in their own place of residence. Full article
(This article belongs to the Special Issue Raspberry Pi Technology)
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Open AccessArticle A Soft Sensor Development for the Rotational Speed Measurement of an Electric Propeller
Electronics 2016, 5(4), 94; doi:10.3390/electronics5040094
Received: 1 November 2016 / Revised: 30 November 2016 / Accepted: 14 December 2016 / Published: 20 December 2016
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Abstract
In recent decades, micro air vehicles driven by electric propellers have become a hot topic, and developed quickly. The performance of the vehicles depends on the rotational speed of propellers, thus, improving the accuracy of rotational speed measurement is beneficial to the vehicle’s
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In recent decades, micro air vehicles driven by electric propellers have become a hot topic, and developed quickly. The performance of the vehicles depends on the rotational speed of propellers, thus, improving the accuracy of rotational speed measurement is beneficial to the vehicle’s performance. This paper presents the development of a soft sensor for the rotational speed measurement of an electric propeller. An adaptive learning algorithm is derived for the soft sensor by using Popov hyperstability theory, based on which a one-step-delay adaptive learning algorithm is further proposed to solve the implementation problem of the soft sensor. It is important to note that only the input signal and the commutation instant of the motor are employed as inputs in the algorithm, which makes it possible to be easily implemented in real-time. The experimental test results have demonstrated the learning performance and the accuracy of the soft sensor. Full article
(This article belongs to the Special Issue Unmanned Aerial Systems/Vehicles (UAS/V) and Drones)
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Open AccessArticle RFID Reader Anticollision Protocols for Dense and Mobile Deployments
Electronics 2016, 5(4), 84; doi:10.3390/electronics5040084
Received: 30 September 2016 / Revised: 17 November 2016 / Accepted: 21 November 2016 / Published: 29 November 2016
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Abstract
The rapid development of RFID (Radio Frequency IDentification) technology has allowed its large adoption and led to increasing deployments of RFID solutions in diverse environments under varying scenarios and constraints. The nature of these constraints ranges from the amount to the mobility of
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The rapid development of RFID (Radio Frequency IDentification) technology has allowed its large adoption and led to increasing deployments of RFID solutions in diverse environments under varying scenarios and constraints. The nature of these constraints ranges from the amount to the mobility of the readers deployed, which in turn highly affects the quality of the RFID system, causing reading collisions. Although several solutions were proposed to engage the issue of reading collision, few were ever concerned with the densification and/or mobility of readers. This paper proposes two distributed TDMA (Time Division Multiple Access) approaches designed to reduce these collisions through local coordination between neighboring devices for different scenarios tested here. The first proposal is based on a reservation phase organized between readers with different priority levels given to readers depending on their previous success. The second one takes advantage of the particular case of RFID collisions, allowing a local and mutual decision of each reader to access or not tags in their vicinity. Simulations were run over different stressful environments in terms of tag/reader density and mobility, proving that our proposals achieved the best performance in terms of throughput, collision avoidance and coverage delay when compared to other collision reducing schemes. Full article
(This article belongs to the Special Issue RFID Systems and Applications)
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Open AccessArticle A Novel 12-Lead ECG T-Shirt with Active Electrodes
Electronics 2016, 5(4), 75; doi:10.3390/electronics5040075
Received: 13 August 2016 / Revised: 19 October 2016 / Accepted: 3 November 2016 / Published: 8 November 2016
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Abstract
We developed an ECG T-shirt with a portable recorder for unobtrusive and long-term multichannel ECG monitoring with active electrodes. A major drawback of conventional 12-lead ECGs is the use of adhesive gel electrodes, which are uncomfortable during long-term application and may even cause
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We developed an ECG T-shirt with a portable recorder for unobtrusive and long-term multichannel ECG monitoring with active electrodes. A major drawback of conventional 12-lead ECGs is the use of adhesive gel electrodes, which are uncomfortable during long-term application and may even cause skin irritations and allergic reactions. Therefore, we integrated comfortable patches of conductive textile into the ECG T-shirt in order to replace the adhesive gel electrodes. In order to prevent signal deterioration, as reported for other textile ECG systems, we attached active circuits on the outside of the T-shirt to further improve the signal quality of the dry electrodes. Finally, we validated the ECG T-shirt against a commercial Holter ECG with healthy volunteers during phases of lying down, sitting, and walking. The 12-lead ECG was successfully recorded with a resulting mean relative error of the RR intervals of 0.96% and mean coverage of 96.6%. Furthermore, the ECG waves of the 12 leads were analyzed separately and showed high accordance. The P-wave had a correlation of 0.703 for walking subjects, while the T-wave demonstrated lower correlations for all three scenarios (lying: 0.817, sitting: 0.710, walking: 0.403). The other correlations for the P, Q, R, and S-waves were all higher than 0.9. This work demonstrates that our ECG T-shirt is suitable for 12-lead ECG recordings while providing a higher level of comfort compared with a commercial Holter ECG. Full article
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Open AccessArticle Energy Aware Pricing in a Three-Tiered Cloud Service Market
Electronics 2016, 5(4), 65; doi:10.3390/electronics5040065
Received: 30 July 2016 / Revised: 8 September 2016 / Accepted: 12 September 2016 / Published: 28 September 2016
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Abstract
We consider a three-tiered cloud service market and propose an energy efficient pricing strategy in this market. Here, the end customers are served by the Software-as-a-Service (SaaS) providers, who implement customized services for their customers. To host these services, these SaaS providers, in
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We consider a three-tiered cloud service market and propose an energy efficient pricing strategy in this market. Here, the end customers are served by the Software-as-a-Service (SaaS) providers, who implement customized services for their customers. To host these services, these SaaS providers, in turn, lease the infrastructure related resources from the Infrastructure-as-a-Service (IaaS) or Platform-as-a-Service (PaaS) providers. In this paper, we propose and evaluate a mechanism for pricing between SaaS providers and Iaas/PaaS providers and between SaaS providers and the end customers. The pricing scheme is designed in a way such that the integration of renewable energy is promoted, which is a very crucial aspect of energy efficiency. Thereafter, we propose a technique to strategically provide an improved Quality of Service (QoS) by deploying more resources than what is computed by the optimization procedure. This technique is based on the square root staffing law in queueing theory. We carry out numerical evaluations with real data traces on electricity price, renewable energy generation, workload, etc., in order to emulate the real dynamics of the cloud service market. We demonstrate that, under practical assumptions, the proposed technique can generate more profit for the service providers operating in the cloud service market. Full article
(This article belongs to the Special Issue Energy Saving in Data Centers)
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Open AccessArticle On the Implementation of the IEC 61850 Standard: Will Different Manufacturer Devices Behave Similarly under Identical Conditions?
Electronics 2016, 5(4), 85; doi:10.3390/electronics5040085
Received: 3 November 2016 / Revised: 22 November 2016 / Accepted: 25 November 2016 / Published: 5 December 2016
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Abstract
Standardization in smart grid communications is necessary to facilitate complex operations of modern power system functions. However, the strong coupling between the cyber and physical domains of the contemporary grid exposes the system to vulnerabilities and thus places more burden on standards’ developers.
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Standardization in smart grid communications is necessary to facilitate complex operations of modern power system functions. However, the strong coupling between the cyber and physical domains of the contemporary grid exposes the system to vulnerabilities and thus places more burden on standards’ developers. As such, standards need to be continuously assessed for reliability and are expected to be implemented properly on field devices. However, the actual implementation of common standards varies between vendors, which may lead to different behaviors of the devices even if present under similar conditions. The work in this paper tested the implementation of the International Electro-technical Commission’s Generic Object Oriented Substation Event GOOSE (IEC 61850 GOOSE) messaging protocol on commercial Intelligent Electronic Devices (IEDs) and the open source libiec61850 library—also used in commercial devices—which showed different behaviors in identical situations. Based on the test results and analysis of some features of the IEC 61850 GOOSE protocol itself, this paper proposes guidelines and recommendations for proper implementation of the standard functionalities. Full article
(This article belongs to the Special Issue Smart Grid Cyber Security)
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Open AccessArticle On Goodput and Energy Measurements of Network Coding Schemes in the Raspberry Pi
Electronics 2016, 5(4), 66; doi:10.3390/electronics5040066
Received: 30 June 2016 / Revised: 16 August 2016 / Accepted: 29 August 2016 / Published: 13 October 2016
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Abstract
Given that next generation networks are expected to be populated by a large number of devices, there is a need for quick deployment and evaluation of alternative mechanisms to cope with the possible generated traffic in large-scale distributed data networks. In this sense,
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Given that next generation networks are expected to be populated by a large number of devices, there is a need for quick deployment and evaluation of alternative mechanisms to cope with the possible generated traffic in large-scale distributed data networks. In this sense, the Raspberry Pi has been a popular network node choice due to its reduced size, processing capabilities, low cost and its support by widely-used operating systems. For information transport, network coding is a new paradigm for fast and reliable data processing in networking and storage systems, which overcomes various limitations of state-of-the-art routing techniques. Therefore, in this work, we provide an in-depth performance evaluation of Random Linear Network Coding (RLNC)-based schemes for the Raspberry Pi Models 1 and 2, by showing the processing speed of the encoding and decoding operations and the corresponding energy consumption. Our results show that, in several scenarios, processing speeds of more than 80 Mbps in the Raspberry Pi Model 1 and 800 Mbps in the Raspberry Pi Model 2 are attainable. Moreover, we show that the processing energy per bit for network coding is below 1 nJ or even an order of magnitude less in these scenarios. Full article
(This article belongs to the Special Issue Raspberry Pi Technology)
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Open AccessArticle Offshore Measurement System for Wave Power—Using Current Loop Feedback
Electronics 2016, 5(4), 86; doi:10.3390/electronics5040086
Received: 28 September 2016 / Revised: 8 November 2016 / Accepted: 29 November 2016 / Published: 7 December 2016
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Abstract
This paper presents the design and testing of a measurement system for wave power generators. The work is part of a project to build a robust and cheap measurement system for offshore monitoring of wave power farms. Due to the harsh offshore environment,
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This paper presents the design and testing of a measurement system for wave power generators. The work is part of a project to build a robust and cheap measurement system for offshore monitoring of wave power farms. Due to the harsh offshore environment, low accessibility and high cost for installation and maintenance, it is of key importance to minimize power consumption, complexity and cost of each measurement unit. For the first prototype, the objective was to measure voltage, current and translator position inside the linear wave power generator. For this, two printed circuit boards (PCBs) were developed, using a two wire current loop transmitter setup. They were tested separately and in a three phase setup inside a wave power generator during onshore tests. To ensure stability, speed and accuracy in the signal transfer, the PCBs were tested for linearity, frequency response and step response. In addition, power consumption was measured, for operational time evaluation. Results show good agreement between expected and measured performance, with an input range of ±1560 V and ±420 A for alternating current measurements and a bandwidth of 10 kHz and 7 kHz, for voltage and current measurements, respectively. The power consumption was measured to 0.5 W for each measurement unit, at 24 V feed. Full article
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Open AccessArticle Component-Based Cartoon Face Generation
Electronics 2016, 5(4), 76; doi:10.3390/electronics5040076
Received: 20 June 2016 / Revised: 19 October 2016 / Accepted: 27 October 2016 / Published: 10 November 2016
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Abstract
In this paper, we present a cartoon face generation method that stands on a component-based facial feature extraction approach. Given a frontal face image as an input, our proposed system has the following stages. First, face features are extracted using an extended Active
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In this paper, we present a cartoon face generation method that stands on a component-based facial feature extraction approach. Given a frontal face image as an input, our proposed system has the following stages. First, face features are extracted using an extended Active Shape Model. Outlines of the components are locally modified using edge detection, template matching and Hermit interpolation. This modification enhances the diversity of output and accuracy of the component matching required for cartoon generation. Second, to bring cartoon-specific features such as shadows, highlights and, especially, stylish drawing, an array of various face photographs and corresponding hand-drawn cartoon faces are collected. These cartoon templates are automatically decomposed into cartoon components using our proposed method for parameterizing cartoon samples, which is fast and simple. Then, using shape matching methods, the appropriate cartoon component is selected and deformed to fit the input face. Finally, a cartoon face is rendered in a vector format using the rendering rules of the selected template. Experimental results demonstrate effectiveness of our approach in generating life-like cartoon faces. Full article
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Open AccessArticle Easy as Pi: A Network Coding Raspberry Pi Testbed
Electronics 2016, 5(4), 67; doi:10.3390/electronics5040067
Received: 19 July 2016 / Revised: 18 September 2016 / Accepted: 28 September 2016 / Published: 13 October 2016
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Abstract
In the near future, upcoming communications and storage networks are expected to tolerate major difficulties produced by huge amounts of data being generated from the Internet of Things (IoT). For these types of networks, strategies and mechanisms based on network coding have appeared
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In the near future, upcoming communications and storage networks are expected to tolerate major difficulties produced by huge amounts of data being generated from the Internet of Things (IoT). For these types of networks, strategies and mechanisms based on network coding have appeared as an alternative to overcome these difficulties in a holistic manner, e.g., without sacrificing the benefit of a given network metric when improving another. There has been recurrent issues on: (i) making large-scale deployments akin to the Internet of Things; (ii) assessing and (iii) replicating the obtained results in preliminary studies. Therefore, finding testbeds that can deal with large-scale deployments and not lose historic data in order to evaluate these mechanisms are greatly needed and desirable from a research perspective. However, this can be hard to manage, not only due to the inherent costs of the hardware, but also due to maintenance challenges. In this paper, we present the required key steps to design, setup and maintain an inexpensive testbed using Raspberry Pi devices for communications and storage networks with network coding capabilities. This testbed can be utilized for any applications requiring results replicability. Full article
(This article belongs to the Special Issue Raspberry Pi Technology)
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Open AccessArticle Guided Modes in a Double-Well Asymmetric Potential of a Graphene Waveguide
Electronics 2016, 5(4), 87; doi:10.3390/electronics5040087
Received: 27 October 2016 / Revised: 28 November 2016 / Accepted: 1 December 2016 / Published: 7 December 2016
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Abstract
The analogy between the electron wave nature in graphene electronics and the electromagnetic waves in dielectrics has suggested a series of optical-like phenomena, which is of great importance for graphene-based electronic devices. In this paper, we propose an asymmetric double-well potential on graphene
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The analogy between the electron wave nature in graphene electronics and the electromagnetic waves in dielectrics has suggested a series of optical-like phenomena, which is of great importance for graphene-based electronic devices. In this paper, we propose an asymmetric double-well potential on graphene as an electronic waveguide to confine the graphene electrons. The guided modes in this graphene waveguide are investigated using a modified transfer matrix method. It is found that there are two types of guided modes. The first kind is confined in one well, which is similar to the asymmetric quantum well graphene waveguide. The second kind can appear in two potential wells with double-degeneracy. Characteristics of all the possible guide modes are presented. Full article
(This article belongs to the Special Issue Two-Dimensional Electronics and Optoelectronics)
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Open AccessArticle A Numerical Estimation of a RFID Reader Field and SAR inside a Blood Bag at UHF
Electronics 2016, 5(4), 77; doi:10.3390/electronics5040077
Received: 23 September 2016 / Revised: 31 October 2016 / Accepted: 4 November 2016 / Published: 8 November 2016
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Abstract
In this paper, the effects of UHF electromagnetic fields produced by a RFID reader on a blood bag are evaluated numerically in several configurations. The results of the simulation, field level and distribution, specific absorption rate (SAR), and heating time show that an
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In this paper, the effects of UHF electromagnetic fields produced by a RFID reader on a blood bag are evaluated numerically in several configurations. The results of the simulation, field level and distribution, specific absorption rate (SAR), and heating time show that an exposure to a typical reader field leads to a temperature increase smaller than 0.1 C and to a SAR smaller than 1 W/kg. As a consequence, no adverse biological effects occur during a typical UHF RFID reading cycle on a blood bag. Therefore, the blood contained in a bag traced using UHF-RFID is as safe as those traced using barcodes. The proposed analysis supports the use of UHF RFID in the blood transfusion supply chain. Full article
(This article belongs to the Special Issue RFID Systems and Applications)
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Open AccessArticle Assessment of a Smart Sensing Shoe for Gait Phase Detection in Level Walking
Electronics 2016, 5(4), 78; doi:10.3390/electronics5040078
Received: 15 August 2016 / Revised: 31 October 2016 / Accepted: 4 November 2016 / Published: 16 November 2016
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Abstract
Gait analysis and more specifically ambulatory monitoring of temporal and spatial gait parameters may open relevant fields of applications in activity tracking, sports and also in the assessment and treatment of specific diseases. Wearable technology can boost this scenario by spreading the adoption
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Gait analysis and more specifically ambulatory monitoring of temporal and spatial gait parameters may open relevant fields of applications in activity tracking, sports and also in the assessment and treatment of specific diseases. Wearable technology can boost this scenario by spreading the adoption of monitoring systems to a wide set of healthy users or patients. In this context, we assessed a recently developed commercial smart shoe—the FootMoov—for automatic gait phase detection in level walking. FootMoov has built-in force sensors and a triaxial accelerometer and is able to transmit the sensor data to the smartphone through a wireless connection. We developed a dedicated gait phase detection algorithm relying both on force and inertial information. We tested the smart shoe on ten healthy subjects in free level walking conditions and in a laboratory setting in comparison with an optical motion capture system. Results confirmed a reliable detection of the gait phases. The maximum error committed, on the order of 44.7 ms, is comparable with previous studies. Our results confirmed the possibility to exploit consumer wearable devices to extract relevant parameters to improve the subject health or to better manage his/her progressions. Full article
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Open AccessArticle GPGPU Accelerated Deep Object Classification on a Heterogeneous Mobile Platform
Electronics 2016, 5(4), 88; doi:10.3390/electronics5040088
Received: 5 September 2016 / Revised: 29 November 2016 / Accepted: 5 December 2016 / Published: 9 December 2016
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Abstract
Deep convolutional neural networks achieve state-of-the-art performance in image classification. The computational and memory requirements of such networks are however huge, and that is an issue on embedded devices due to their constraints. Most of this complexity derives from the convolutional layers and
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Deep convolutional neural networks achieve state-of-the-art performance in image classification. The computational and memory requirements of such networks are however huge, and that is an issue on embedded devices due to their constraints. Most of this complexity derives from the convolutional layers and in particular from the matrix multiplications they entail. This paper proposes a complete approach to image classification providing common layers used in neural networks. Namely, the proposed approach relies on a heterogeneous CPU-GPU scheme for performing convolutions in the transform domain. The Compute Unified Device Architecture(CUDA)-based implementation of the proposed approach is evaluated over three different image classification networks on a Tegra K1 CPU-GPU mobile processor. Experiments show that the presented heterogeneous scheme boasts a 50× speedup over the CPU-only reference and outperforms a GPU-based reference by 2×, while slashing the power consumption by nearly 30%. Full article
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Open AccessArticle A Multi-Slope Sliding-Mode Control Approach for Single-Phase Inverters under Different Loads
Electronics 2016, 5(4), 68; doi:10.3390/electronics5040068
Received: 18 July 2016 / Revised: 28 September 2016 / Accepted: 7 October 2016 / Published: 14 October 2016
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Abstract
In this paper, a new approach to the sliding-mode control of single-phase inverters under linear and non-linear loads is introduced. The main idea behind this approach is to utilize a non-linear, flexible and multi-slope function in controller structure. This non-linear function makes the
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In this paper, a new approach to the sliding-mode control of single-phase inverters under linear and non-linear loads is introduced. The main idea behind this approach is to utilize a non-linear, flexible and multi-slope function in controller structure. This non-linear function makes the controller possible to control the inverter by a non-linear multi-slope sliding surface. In general, this sliding surface has two parts with different slopes in each part and the flexibility of the sliding surface makes the multi-slope sliding-mode controller (MSSMC) possible to reduce the total harmonic distortion, to improve the tracking accuracy, and to prevent overshoots leading to undesirable transient-states in output voltage that occur when the load current sharply rises. In order to improve the tracking accuracy and to reduce the steady-state error, an integral term of the multi-slope function is also added to the sliding surface. The improved performance of the proposed controller is confirmed by simulations and finally, the results of the proposed approach are compared with a conventional sliding-mode controller (SMC) and a synchronous reference frame PI (SRFPI) controller. Full article
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Open AccessArticle A Pulsed Coding Technique Based on Optical UWB Modulation for High Data Rate Low Power Wireless Implantable Biotelemetry
Electronics 2016, 5(4), 69; doi:10.3390/electronics5040069
Received: 14 June 2016 / Revised: 30 September 2016 / Accepted: 10 October 2016 / Published: 17 October 2016
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Abstract
This paper reports on a pulsed coding technique based on optical Ultra-wideband (UWB) modulation for wireless implantable biotelemetry systems allowing for high data rate link whilst enabling significant power reduction compared to the state-of-the-art. This optical data coding approach is suitable for emerging
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This paper reports on a pulsed coding technique based on optical Ultra-wideband (UWB) modulation for wireless implantable biotelemetry systems allowing for high data rate link whilst enabling significant power reduction compared to the state-of-the-art. This optical data coding approach is suitable for emerging biomedical applications like transcutaneous neural wireless communication systems. The overall architecture implementing this optical modulation technique employs sub-nanosecond pulsed laser as the data transmitter and small sensitive area photodiode as the data receiver. Moreover, it includes coding and decoding digital systems, biasing and driving analogue circuits for laser pulse generation and photodiode signal conditioning. The complete system has been implemented on Field-Programmable Gate Array (FPGA) and prototype Printed Circuit Board (PCB) with discrete off-the-shelf components. By inserting a diffuser between the transmitter and the receiver to emulate skin/tissue, the system is capable to achieve a 128 Mbps data rate with a bit error rate less than 10−9 and an estimated total power consumption of about 5 mW corresponding to a power efficiency of 35.9 pJ/bit. These results could allow, for example, the transmission of an 800-channel neural recording interface sampled at 16 kHz with 10-bit resolution. Full article
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Open AccessArticle Operating Wireless Sensor Nodes without Energy Storage: Experimental Results with Transient Computing
Electronics 2016, 5(4), 89; doi:10.3390/electronics5040089
Received: 22 November 2016 / Revised: 2 December 2016 / Accepted: 6 December 2016 / Published: 9 December 2016
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Abstract
Energy harvesting is increasingly used for powering wireless sensor network nodes. Recently, it has been suggested to combine it with the concept of transient computing whereby the wireless sensor nodes operate without energy storage capabilities. This new combined approach brings benefits, for instance
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Energy harvesting is increasingly used for powering wireless sensor network nodes. Recently, it has been suggested to combine it with the concept of transient computing whereby the wireless sensor nodes operate without energy storage capabilities. This new combined approach brings benefits, for instance ultra-low power nodes and reduced maintenance, but also raises new challenges, foremost dealing with nodes that may be left without power for various time periods. Although transient computing has been demonstrated on microcontrollers, reports on experiments with wireless sensor nodes are still scarce in the literature. In this paper, we describe our experiments with solar, thermal, and RF energy harvesting sources that are used to power sensor nodes (including wireless ones) without energy storage, but with transient computing capabilities. The results show that the selected solar and thermal energy sources can operate both the wired and wireless nodes without energy storage, whereas in our specific implementation, the developed RF energy source can only be used for the selected nodes without wireless connectivity. Full article
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Open AccessArticle Enhancing the Performance of the Data Embedment Process through Encoding Errors
Electronics 2016, 5(4), 79; doi:10.3390/electronics5040079
Received: 21 August 2016 / Revised: 11 November 2016 / Accepted: 14 November 2016 / Published: 22 November 2016
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Abstract
Image steganography is a multipurpose-serving key emerging technology that is used for covertly transferring, storing, and governing various digital data, including intellectual properties and copyrights, social media data, multimedia data, and secrets of law-enforcing agencies. During the management in the stated information, nowadays,
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Image steganography is a multipurpose-serving key emerging technology that is used for covertly transferring, storing, and governing various digital data, including intellectual properties and copyrights, social media data, multimedia data, and secrets of law-enforcing agencies. During the management in the stated information, nowadays, massive amounts of data are handled that require greater security. For that purpose, data are embedded into a cover image to hide them from any intruders. Nevertheless, the requirements of a larger embedding capacity, improved stego-image quality, and reduced time complexity is increasing. In this paper, the authors have presented a novel data-embedding scheme where the prediction error-based data-hiding scheme is modified in an intricate way so that all the image pixels can accept secret bits. A distance matrix between the pixel values of each image block and a reference value are measured first. Thereafter, the distances are encoded into two states: 1 and −1. That encoding process enables the scheme to implant one bit in every pixel of the cover image. During the bit implantation, the errors 1 and −1 are modified by shifting them to the right and left directions, respectively. This strategy enhances the embedding capacity by a factor of more than 2. The use of reference values reduces the computational complexity notably, and in the meanwhile increases the security and robustness of the scheme because the reference values are not open to any third party. The scheme also reduces the time complexity by 2–16 times with compared to its competing schemes. Experimental results prove the superiority of the proposed algorithm on embedding capacity, visual quality, and time complexity compared to the current well-accepted existing schemes. Full article
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Review

Jump to: Research

Open AccessReview Photonic Structure-Integrated Two-Dimensional Material Optoelectronics
Electronics 2016, 5(4), 93; doi:10.3390/electronics5040093
Received: 25 October 2016 / Revised: 5 December 2016 / Accepted: 9 December 2016 / Published: 20 December 2016
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Abstract
The rapid development and unique properties of two-dimensional (2D) materials, such as graphene, phosphorene and transition metal dichalcogenides enable them to become intriguing candidates for future optoelectronic applications. To maximize the potential of 2D material-based optoelectronics, various photonic structures are integrated to form
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The rapid development and unique properties of two-dimensional (2D) materials, such as graphene, phosphorene and transition metal dichalcogenides enable them to become intriguing candidates for future optoelectronic applications. To maximize the potential of 2D material-based optoelectronics, various photonic structures are integrated to form photonic structure/2D material hybrid systems so that the device performance can be manipulated in controllable ways. Here, we first introduce the photocurrent-generation mechanisms of 2D material-based optoelectronics and their performance. We then offer an overview and evaluation of the state-of-the-art of hybrid systems, where 2D material optoelectronics are integrated with photonic structures, especially plasmonic nanostructures, photonic waveguides and crystals. By combining with those photonic structures, the performance of 2D material optoelectronics can be further enhanced, and on the other side, a high-performance modulator can be achieved by electrostatically tuning 2D materials. Finally, 2D material-based photodetector can also become an efficient probe to learn the light-matter interactions of photonic structures. Those hybrid systems combine the advantages of 2D materials and photonic structures, providing further capacity for high-performance optoelectronics. Full article
(This article belongs to the Special Issue Two-Dimensional Electronics and Optoelectronics)
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