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Electronics, Volume 5, Issue 3 (September 2016)

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Open AccessArticle
Low Delay Video Streaming on the Internet of Things Using Raspberry Pi
Electronics 2016, 5(3), 60; https://doi.org/10.3390/electronics5030060
Received: 29 April 2016 / Revised: 7 September 2016 / Accepted: 13 September 2016 / Published: 20 September 2016
Cited by 7 | Viewed by 2915 | PDF Full-text (967 KB) | HTML Full-text | XML Full-text
Abstract
The Internet of Things is predicted to consist of over 50 billion devices aiming to solve problems in most areas of our digital society. A large part of the data communicated is expected to consist of various multimedia contents, such as live audio [...] Read more.
The Internet of Things is predicted to consist of over 50 billion devices aiming to solve problems in most areas of our digital society. A large part of the data communicated is expected to consist of various multimedia contents, such as live audio and video. This article presents a solution for the communication of high definition video in low-delay scenarios (<200 ms) under the constraints of devices with limited hardware resources, such as the Raspberry Pi. We verify that it is possible to enable low delay video streaming between Raspberry Pi devices using a distributed Internet of Things system called the SensibleThings platform. Specifically, our implementation transfers a 6 Mbps H.264 video stream of 1280 × 720 pixels at 25 frames per second between devices with a total delay of 181 ms on the public Internet, of which the overhead of the distributed Internet of Things communication platform only accounts for 18 ms of this delay. We have found that the most significant bottleneck of video transfer on limited Internet of Things devices is the video coding and not the distributed communication platform, since the video coding accounts for 90% of the total delay. Full article
(This article belongs to the Special Issue Raspberry Pi Technology) Printed Edition available
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Open AccessArticle
Robust and Accurate Algorithm for Wearable Stereoscopic Augmented Reality with Three Indistinguishable Markers
Electronics 2016, 5(3), 59; https://doi.org/10.3390/electronics5030059
Received: 18 May 2016 / Revised: 8 September 2016 / Accepted: 9 September 2016 / Published: 19 September 2016
Cited by 10 | Viewed by 2804 | PDF Full-text (3999 KB) | HTML Full-text | XML Full-text | Supplementary Files
Abstract
In the context of surgical navigation systems based on augmented reality (AR), the key challenge is to ensure the highest degree of realism in merging computer-generated elements with live views of the surgical scene. This paper presents an algorithm suited for wearable stereoscopic [...] Read more.
In the context of surgical navigation systems based on augmented reality (AR), the key challenge is to ensure the highest degree of realism in merging computer-generated elements with live views of the surgical scene. This paper presents an algorithm suited for wearable stereoscopic augmented reality video see-through systems for use in a clinical scenario. A video-based tracking solution is proposed that relies on stereo localization of three monochromatic markers rigidly constrained to the scene. A PnP-based optimization step is introduced to refine separately the pose of the two cameras. Video-based tracking methods using monochromatic markers are robust to non-controllable and/or inconsistent lighting conditions. The two-stage camera pose estimation algorithm provides sub-pixel registration accuracy. From a technological and an ergonomic standpoint, the proposed approach represents an effective solution to the implementation of wearable AR-based surgical navigation systems wherever rigid anatomies are involved. Full article
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Open AccessArticle
Monitoring and Analyzing of Circadian and Ultradian Locomotor Activity Based on Raspberry-Pi
Electronics 2016, 5(3), 58; https://doi.org/10.3390/electronics5030058
Received: 1 June 2016 / Revised: 24 August 2016 / Accepted: 12 September 2016 / Published: 15 September 2016
Cited by 5 | Viewed by 2304 | PDF Full-text (9290 KB) | HTML Full-text | XML Full-text
Abstract
A new device based on the Raspberry-Pi to monitor the locomotion of Arctic marine invertebrates and to analyze chronobiologic data has been made, tested and deployed. The device uses infrared sensors to monitor and record the locomotor activity of the animals, which is [...] Read more.
A new device based on the Raspberry-Pi to monitor the locomotion of Arctic marine invertebrates and to analyze chronobiologic data has been made, tested and deployed. The device uses infrared sensors to monitor and record the locomotor activity of the animals, which is later analyzed. The software package consists of two separate scripts: the first designed to manage the acquisition and the evolution of the experiment, the second designed to generate actograms and perform various analyses to detect periodicity in the data (e.g., Fourier power spectra, chi-squared periodograms, and Lomb–Scargle periodograms). The data acquisition hardware and the software has been previously tested during an Arctic mission with an arctic marine invertebrate. Full article
(This article belongs to the Special Issue Raspberry Pi Technology) Printed Edition available
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Open AccessArticle
A Robust Automated Cataract Detection Algorithm Using Diagnostic Opinion Based Parameter Thresholding for Telemedicine Application
Electronics 2016, 5(3), 57; https://doi.org/10.3390/electronics5030057
Received: 29 June 2016 / Revised: 2 August 2016 / Accepted: 6 September 2016 / Published: 15 September 2016
Cited by 5 | Viewed by 2300 | PDF Full-text (3128 KB) | HTML Full-text | XML Full-text
Abstract
This paper proposes and evaluates an algorithm to automatically detect the cataracts from color images in adult human subjects. Currently, methods available for cataract detection are based on the use of either fundus camera or Digital Single-Lens Reflex (DSLR) camera; both are very [...] Read more.
This paper proposes and evaluates an algorithm to automatically detect the cataracts from color images in adult human subjects. Currently, methods available for cataract detection are based on the use of either fundus camera or Digital Single-Lens Reflex (DSLR) camera; both are very expensive. The main motive behind this work is to develop an inexpensive, robust and convenient algorithm which in conjugation with suitable devices will be able to diagnose the presence of cataract from the true color images of an eye. An algorithm is proposed for cataract screening based on texture features: uniformity, intensity and standard deviation. These features are first computed and mapped with diagnostic opinion by the eye expert to define the basic threshold of screening system and later tested on real subjects in an eye clinic. Finally, a tele-ophthamology model using our proposed system has been suggested, which confirms the telemedicine application of the proposed system. Full article
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Open AccessArticle
Raspberry Pi: An Effective Vehicle in Teaching the Internet of Things in Computer Science and Engineering
Electronics 2016, 5(3), 56; https://doi.org/10.3390/electronics5030056
Received: 1 May 2016 / Revised: 1 September 2016 / Accepted: 8 September 2016 / Published: 13 September 2016
Cited by 8 | Viewed by 3139 | PDF Full-text (3342 KB) | HTML Full-text | XML Full-text
Abstract
The Raspberry Pi is being increasingly adopted as a suitable platform in both research and applications of the Internet of Things (IoT). This study presents a novel project-based teaching and learning approach devised in an Internet of Things course for undergraduate students in [...] Read more.
The Raspberry Pi is being increasingly adopted as a suitable platform in both research and applications of the Internet of Things (IoT). This study presents a novel project-based teaching and learning approach devised in an Internet of Things course for undergraduate students in the computer science major, where the Raspberry Pi platform is used as an effective vehicle to greatly enhance students’ learning performance and experience. The devised course begins with learning simple hardware and moves to building a whole prototype system. This paper illustrates the outcome of the proposed approach by demonstrating the prototype IoT systems designed and developed by students at the end of one such IoT course. Furthermore, this study provides insights and lessons regarding how to facilitate the use of the Raspberry Pi platform to successfully achieve the goals of project-based teaching and learning in IoT. Full article
(This article belongs to the Special Issue Raspberry Pi Technology) Printed Edition available
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Open AccessArticle
Two Micron Pixel Pitch Active Matrix Spatial Light Modulator Driven by Spin Transfer Switching
Electronics 2016, 5(3), 55; https://doi.org/10.3390/electronics5030055
Received: 28 June 2016 / Revised: 16 August 2016 / Accepted: 1 September 2016 / Published: 9 September 2016
Cited by 5 | Viewed by 2773 | PDF Full-text (3868 KB) | HTML Full-text | XML Full-text
Abstract
We have developed an active matrix-addressed magneto-optical spatial light modulator driven by spin-transfer switching (spin-SLM) which has a 100 × 100 array pixel layout with a 2 µm pixel pitch. It has pixel-selection-transistors and logic circuits which convert serial data into parallel data [...] Read more.
We have developed an active matrix-addressed magneto-optical spatial light modulator driven by spin-transfer switching (spin-SLM) which has a 100 × 100 array pixel layout with a 2 µm pixel pitch. It has pixel-selection-transistors and logic circuits which convert serial data into parallel data to reduce input terminals. We have confirmed successful magnetization switching of each pixel by injecting a pulse current generated from the logic circuit, and its optical display capability by showing digital characters. Full article
(This article belongs to the Special Issue Spin Optoelectronics)
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Open AccessArticle
Building IoT Applications with Raspberry Pi and Low Power IQRF Communication Modules
Electronics 2016, 5(3), 54; https://doi.org/10.3390/electronics5030054
Received: 16 May 2016 / Revised: 18 August 2016 / Accepted: 1 September 2016 / Published: 8 September 2016
Cited by 4 | Viewed by 2797 | PDF Full-text (5394 KB) | HTML Full-text | XML Full-text
Abstract
Typical Internet of Things (IoT) applications involve collecting information automatically from diverse geographically-distributed smart sensors and concentrating the information into more powerful computers. The Raspberry Pi platform has become a very interesting choice for IoT applications for several reasons: (1) good computing power/cost [...] Read more.
Typical Internet of Things (IoT) applications involve collecting information automatically from diverse geographically-distributed smart sensors and concentrating the information into more powerful computers. The Raspberry Pi platform has become a very interesting choice for IoT applications for several reasons: (1) good computing power/cost ratio; (2) high availability; it has become a de facto hardware standard; and (3) ease of use; it is based on operating systems with a big community of users. In IoT applications, data are frequently carried by means of wireless sensor networks in which energy consumption is a key issue. Energy consumption is especially relevant for smart sensors that are scattered over wide geographical areas and may need to work unattended on batteries for long intervals of time. In this scenario, it is convenient to ease the construction of IoT applications while keeping energy consumption to a minimum at the sensors. This work proposes a possible gateway implementation with specific technologies. It solves the following research question: how to build gateways for IoT applications with Raspberry Pi and low power IQRF communication modules. The following contributions are presented: (1) one architecture for IoT gateways that integrates data from sensor nodes into a higher level application based on low-cost/low-energy technologies; (2) bindings in Java and C that ease the construction of IoT applications; (3) an empirical model that describes the consumption of the communications at the nodes (smart sensors) and allows scaling their batteries; and (4) validation of the proposed energy model at the battery-operated nodes. Full article
(This article belongs to the Special Issue Raspberry Pi Technology) Printed Edition available
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Open AccessArticle
ROSMOD: A Toolsuite for Modeling, Generating, Deploying, and Managing Distributed Real-time Component-based Software using ROS
Electronics 2016, 5(3), 53; https://doi.org/10.3390/electronics5030053
Received: 1 April 2016 / Revised: 23 August 2016 / Accepted: 23 August 2016 / Published: 7 September 2016
Cited by 1 | Viewed by 2693 | PDF Full-text (38452 KB) | HTML Full-text | XML Full-text
Abstract
This paper presents the Robot Operating System Model-driven development tool suite, (ROSMOD) an integrated development environment for rapid prototyping component-based software for the Robot Operating System (ROS) middleware. ROSMOD is well suited for the design, development and deployment of large-scale distributed applications on [...] Read more.
This paper presents the Robot Operating System Model-driven development tool suite, (ROSMOD) an integrated development environment for rapid prototyping component-based software for the Robot Operating System (ROS) middleware. ROSMOD is well suited for the design, development and deployment of large-scale distributed applications on embedded devices. We present the various features of ROSMOD including the modeling language, the graphical user interface, code generators, and deployment infrastructure. We demonstrate the utility of this tool with a real-world case study: an Autonomous Ground Support Equipment (AGSE) robot that was designed and prototyped using ROSMOD for the NASA Student Launch competition, 2014–2015. Full article
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Open AccessArticle
Numerical Drift-Diffusion Simulation of GaAs p-i-n and Schottky-Barrier Photodiodes for High-Speed AIIIBV On-Chip Optical Interconnections
Electronics 2016, 5(3), 52; https://doi.org/10.3390/electronics5030052
Received: 3 July 2016 / Revised: 26 August 2016 / Accepted: 30 August 2016 / Published: 7 September 2016
Cited by 3 | Viewed by 2806 | PDF Full-text (3837 KB) | HTML Full-text | XML Full-text
Abstract
In this paper, we consider the problem of the research and development of high-speed semiconductor photodetectors suitable for operation as parts of on-chip optical interconnections together with the high-speed laser modulators based on the AIIIBV nanoheterostructures. This research is aimed [...] Read more.
In this paper, we consider the problem of the research and development of high-speed semiconductor photodetectors suitable for operation as parts of on-chip optical interconnections together with the high-speed laser modulators based on the AIIIBV nanoheterostructures. This research is aimed at the development of the models and modelling aids designed for the simulation of carrier transport and accumulation processes taking place in on-chip photosensitive devices during the detection of subpicosecond laser pulses. Another aim of the paper is to apply the aforementioned aids for the investigation of GaAs p-i-n and Schottky-barrier photodiodes. We propose the non-stationary drift-diffusion models, an original numerical simulation technique and the applied software allowing one to simulate the photosensitive devices with different electrophysical, constructive and technological parameters. We have taken into account different kinds of carrier generation and recombination processes, the effects of electron intervalley transition and carrier drift velocity saturation in order to improve the simulation results’ adequacy. We have concluded that the influence of these effects on the performance of photodetectors for on-chip optical interconnections is significant. The response time of GaAs p-i-n and Schottky-barrier photodiodes calculated taking into account the drift velocity dependence on electric field intensity is insufficient for the adequate detection of subpicosecond laser pulses. According to the simulation results, it is reasonable to develop the methods aimed at the increase in the drift velocity of charge carriers in the photodetector active region by means of built-in electric field reduction. Full article
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Open AccessArticle
Miniaturized Blood Pressure Telemetry System with RFID Interface
Electronics 2016, 5(3), 51; https://doi.org/10.3390/electronics5030051
Received: 23 May 2016 / Revised: 5 August 2016 / Accepted: 22 August 2016 / Published: 30 August 2016
Cited by 4 | Viewed by 2272 | PDF Full-text (3319 KB) | HTML Full-text | XML Full-text
Abstract
This work deals with the development and characterization of a potentially implantable blood pressure telemetry system, based on an active Radio-Frequency IDentification (RFID) tag, International Organization for Standardization (ISO) 15693 compliant. This approach aims to continuously measure the average, systolic and diastolic blood [...] Read more.
This work deals with the development and characterization of a potentially implantable blood pressure telemetry system, based on an active Radio-Frequency IDentification (RFID) tag, International Organization for Standardization (ISO) 15693 compliant. This approach aims to continuously measure the average, systolic and diastolic blood pressure of the small/medium animals. The measured pressure wave undergoes embedded processing and results are stored onboard in a non-volatile memory, providing the data under interrogation by an external RFID reader. In order to extend battery lifetime, RFID energy harvesting has been investigated. The paper presents the experimental characterization in a laboratory and preliminary in-vivo tests. The device is a prototype mainly intended, in a future engineered version, for monitoring freely moving test animals for pharmaceutical research and drug safety assessment purposes, but it could have multiple uses in environmental and industrial applications. Full article
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Open AccessArticle
Design and Prototyping Flow of Flexible and Efficient NISC-Based Architectures for MIMO Turbo Equalization and Demapping
Electronics 2016, 5(3), 50; https://doi.org/10.3390/electronics5030050
Received: 31 March 2016 / Revised: 25 July 2016 / Accepted: 22 August 2016 / Published: 30 August 2016
Cited by 4 | Viewed by 2472 | PDF Full-text (4693 KB) | HTML Full-text | XML Full-text
Abstract
In the domain of digital wireless communication, flexible design implementations are increasingly explored for different applications in order to cope with diverse system configurations imposed by the emerging wireless communication standards. In fact, shrinking the design time to meet market pressure, on the [...] Read more.
In the domain of digital wireless communication, flexible design implementations are increasingly explored for different applications in order to cope with diverse system configurations imposed by the emerging wireless communication standards. In fact, shrinking the design time to meet market pressure, on the one hand, and adding the emerging flexibility requirement and, hence, increasing system complexity, on the other hand, require a productive design approach that also ensures final design quality. The no instruction set computer (NISC) approach fulfills these design requirements by eliminating the instruction set overhead. The approach offers static scheduling of the datapath, automated register transfer language (RTL)synthesis and allows the designer to have direct control of hardware resources. This paper presents a complete NISC-based design and prototype flow, from architecture specification till FPGA implementation. The proposed design and prototype flow is illustrated through two case studies of flexible implementations, which are dedicated to low-complexity MIMO turbo-equalizer and a universal turbo-demapper. Moreover, the flexibility of the proposed prototypes allows supporting all communication modes defined in the emerging wireless communication standards, such LTE, LTE-Advanced, WiMAX, WiFi and DVB-RCS. For each prototype, its functionality is evaluated, and the resultant performance is verified for all system configurations. Full article
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Open AccessArticle
Impact of Degraded Communication on Interdependent Power Systems: The Application of Grid Splitting
Electronics 2016, 5(3), 49; https://doi.org/10.3390/electronics5030049
Received: 4 June 2016 / Revised: 19 August 2016 / Accepted: 22 August 2016 / Published: 29 August 2016
Cited by 1 | Viewed by 2119 | PDF Full-text (4731 KB) | HTML Full-text | XML Full-text
Abstract
Communication is increasingly present for managing and controlling critical infrastructures strengthening their cyber interdependencies. In electric power systems, grid splitting is a topical communication-critical application. It amounts to separating a power system into islands in response to an impending instability, e.g., loss of [...] Read more.
Communication is increasingly present for managing and controlling critical infrastructures strengthening their cyber interdependencies. In electric power systems, grid splitting is a topical communication-critical application. It amounts to separating a power system into islands in response to an impending instability, e.g., loss of generator synchronism due to a component fault, by appropriately disconnecting transmission lines and grouping synchronous generators. The successful application of grid splitting depends on the communication infrastructure to collect system-wide synchronized measurements and to relay the command to open line switches. Grid splitting may be ineffective if communication is degraded and its outcome may also depend on the system loading conditions. This paper investigates the effects of degraded communication and load variability on grid splitting. To this aim, a communication delay model is coupled with a transient electrical model and applied to the IEEE 39-Bus and the IEEE 118-Bus Test System. Case studies show that the loss of generator synchronism following a fault is mitigated by timely splitting the network into islands. On the other hand, the results show that communication delays and increased network flows can degrade the performance of grid splitting. The developed framework enables the identification of the requirements of the dedicated communication infrastructure for a successful grid-splitting procedure. Full article
(This article belongs to the Special Issue Smart Grid Cyber Security)
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Open AccessReview
A Comparative Review of Footwear-Based Wearable Systems
Electronics 2016, 5(3), 48; https://doi.org/10.3390/electronics5030048
Received: 14 July 2016 / Revised: 28 July 2016 / Accepted: 1 August 2016 / Published: 10 August 2016
Cited by 21 | Viewed by 3598 | PDF Full-text (1348 KB) | HTML Full-text | XML Full-text
Abstract
Footwear is an integral part of daily life. Embedding sensors and electronics in footwear for various different applications started more than two decades ago. This review article summarizes the developments in the field of footwear-based wearable sensors and systems. The electronics, sensing technologies, [...] Read more.
Footwear is an integral part of daily life. Embedding sensors and electronics in footwear for various different applications started more than two decades ago. This review article summarizes the developments in the field of footwear-based wearable sensors and systems. The electronics, sensing technologies, data transmission, and data processing methodologies of such wearable systems are all principally dependent on the target application. Hence, the article describes key application scenarios utilizing footwear-based systems with critical discussion on their merits. The reviewed application scenarios include gait monitoring, plantar pressure measurement, posture and activity classification, body weight and energy expenditure estimation, biofeedback, navigation, and fall risk applications. In addition, energy harvesting from the footwear is also considered for review. The article also attempts to shed light on some of the most recent developments in the field along with the future work required to advance the field. Full article
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Open AccessArticle
An Embedded Sensing and Communication Platform, and a Healthcare Model for Remote Monitoring of Chronic Diseases
Electronics 2016, 5(3), 47; https://doi.org/10.3390/electronics5030047
Received: 18 June 2016 / Revised: 24 July 2016 / Accepted: 25 July 2016 / Published: 4 August 2016
Cited by 8 | Viewed by 3125 | PDF Full-text (4744 KB) | HTML Full-text | XML Full-text
Abstract
This paper presents a new remote healthcare model, which, exploiting wireless biomedical sensors, an embedded local unit (gateway) for sensor data acquisition-processing-communication, and a remote e-Health service center, can be scaled in different telemedicine scenarios. The aim is avoiding hospitalization cost and long [...] Read more.
This paper presents a new remote healthcare model, which, exploiting wireless biomedical sensors, an embedded local unit (gateway) for sensor data acquisition-processing-communication, and a remote e-Health service center, can be scaled in different telemedicine scenarios. The aim is avoiding hospitalization cost and long waiting lists for patients affected by chronic illness who need continuous and long-term monitoring of some vital parameters. In the “1:1” scenario, the patient has a set of biomedical sensors and a gateway to exchange data and healthcare protocols with the remote service center. In the “1:N” scenario the use of gateway and sensors is managed by a professional caregiver, e.g., assigned by the Public Health System to a number N of different patients. In the “point of care” scenario the patient, instead of being hospitalized, can take the needed measurements at a specific health corner, which is then connected to the remote e-Health center. A mix of commercially available sensors and new custom-designed ones is presented. The new custom-designed sensors range from a single-lead electrocardiograph for easy measurements taken by the patients at their home, to a multi-channel biomedical integrated circuit for acquisition of multi-channel bio signals, to a new motion sensor for patient posture estimation and fall detection. Experimental trials in real-world telemedicine applications assess the proposed system in terms of easy usability from patients, specialist and family doctors, and caregivers, in terms of scalability in different scenarios, and in terms of suitability for implementation of needed care plans. Full article
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Open AccessFeature PaperArticle
Skin Admittance Measurement for Emotion Recognition: A Study over Frequency Sweep
Electronics 2016, 5(3), 46; https://doi.org/10.3390/electronics5030046
Received: 26 June 2016 / Revised: 28 July 2016 / Accepted: 1 August 2016 / Published: 4 August 2016
Cited by 8 | Viewed by 2253 | PDF Full-text (546 KB) | HTML Full-text | XML Full-text
Abstract
The electrodermal activity (EDA) is a reliable physiological signal for monitoring the sympathetic nervous system. Several studies have demonstrated that EDA can be a source of effective markers for the assessment of emotional states in humans. There are two main methods for measuring [...] Read more.
The electrodermal activity (EDA) is a reliable physiological signal for monitoring the sympathetic nervous system. Several studies have demonstrated that EDA can be a source of effective markers for the assessment of emotional states in humans. There are two main methods for measuring EDA: endosomatic (internal electrical source) and exosomatic (external electrical source). Even though the exosomatic approach is the most widely used, differences between alternating current (AC) and direct current (DC) methods and their implication in the emotional assessment field have not yet been deeply investigated. This paper aims at investigating how the admittance contribution of EDA, studied at different frequency sources, affects the EDA statistical power in inferring on the subject’s arousing level (neutral or aroused). To this extent, 40 healthy subjects underwent visual affective elicitations, including neutral and arousing levels, while EDA was gathered through DC and AC sources from 0 to 1 kHz. Results concern the accuracy of an automatic, EDA feature-based arousal recognition system for each frequency source. We show how the frequency of the external electrical source affects the accuracy of arousal recognition. This suggests a role of skin susceptance in the study of affective stimuli through electrodermal response. Full article
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Open AccessArticle
Wearable Multimodal Skin Sensing for the Diabetic Foot
Electronics 2016, 5(3), 45; https://doi.org/10.3390/electronics5030045
Received: 29 January 2016 / Revised: 27 May 2016 / Accepted: 4 July 2016 / Published: 28 July 2016
Cited by 3 | Viewed by 2283 | PDF Full-text (2266 KB) | HTML Full-text | XML Full-text | Supplementary Files
Abstract
Ulceration of the diabetic foot is currently difficult to detect reliably in a timely manner causing undue suffering and cost. Current best practice is for daily monitoring by those living with diabetes coupled to scheduled monitoring by the incumbent care provider. Although some [...] Read more.
Ulceration of the diabetic foot is currently difficult to detect reliably in a timely manner causing undue suffering and cost. Current best practice is for daily monitoring by those living with diabetes coupled to scheduled monitoring by the incumbent care provider. Although some metrics have proven useful in the detection or prediction of ulceration, no single metric can currently be relied upon for diagnosis. We have developed a prototype multivariate extensible sensor platform with which we demonstrate the ability to gather acceleration, rotation, galvanic skin response, environmental temperature, humidity, force, skin temperature and bioimpedance signals in real time, for later analysis, utilising low cost Raspberry Pi and Arduino devices. We demonstrate the utility of the Raspberry Pi computer in research which is of particular interest to this issue of electronics—Raspberry Pi edition. We conclude that the hardware presented shows potential as an adaptable research tool capable of gathering synchronous data over multiple sensor modalities. This research tool will be utilised to optimise sensor selection, placement and algorithm development prior to translation into a sock, insole or platform diagnostic device at a later date. The combination of a number of clinically relevant parameters is expected to provide greater understanding of tissue state in the foot but requires further volunteer testing and analysis beyond the scope of this paper which will be reported in due course. Full article
(This article belongs to the Special Issue Raspberry Pi Technology) Printed Edition available
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Open AccessReview
A Fabric-Based Approach for Wearable Haptics
Electronics 2016, 5(3), 44; https://doi.org/10.3390/electronics5030044
Received: 24 May 2016 / Revised: 15 July 2016 / Accepted: 20 July 2016 / Published: 26 July 2016
Cited by 8 | Viewed by 2087 | PDF Full-text (1893 KB) | HTML Full-text | XML Full-text
Abstract
In recent years, wearable haptic systems (WHS) have gained increasing attention as a novel and exciting paradigm for human–robot interaction (HRI). These systems can be worn by users, carried around, and integrated in their everyday lives, thus enabling a more natural manner to [...] Read more.
In recent years, wearable haptic systems (WHS) have gained increasing attention as a novel and exciting paradigm for human–robot interaction (HRI). These systems can be worn by users, carried around, and integrated in their everyday lives, thus enabling a more natural manner to deliver tactile cues. At the same time, the design of these types of devices presents new issues: the challenge is the correct identification of design guidelines, with the two-fold goal of minimizing system encumbrance and increasing the effectiveness and naturalness of stimulus delivery. Fabrics can represent a viable solution to tackle these issues. They are specifically thought “to be worn”, and could be the key ingredient to develop wearable haptic interfaces conceived for a more natural HRI. In this paper, the author will review some examples of fabric-based WHS that can be applied to different body locations, and elicit different haptic perceptions for different application fields. Perspective and future developments of this approach will be discussed. Full article
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Open AccessArticle
A Raspberry Pi Based Portable Endoscopic 3D Measurement System
Electronics 2016, 5(3), 43; https://doi.org/10.3390/electronics5030043
Received: 29 April 2016 / Revised: 15 July 2016 / Accepted: 18 July 2016 / Published: 26 July 2016
Cited by 2 | Viewed by 2516 | PDF Full-text (12981 KB) | HTML Full-text | XML Full-text | Supplementary Files
Abstract
Geometry measurements are very important to monitor a machine part’s health and performance. Optical measurement system have several advantages for the acquisition of a parts geometry: measurement speed, precision, point density and contactless operation. Measuring parts inside of assembled machines is also desirable [...] Read more.
Geometry measurements are very important to monitor a machine part’s health and performance. Optical measurement system have several advantages for the acquisition of a parts geometry: measurement speed, precision, point density and contactless operation. Measuring parts inside of assembled machines is also desirable to keep maintenance cost low. The Raspberry Pi is a small and cost efficient computer that creates new opportunities for compact measurement systems. We have developed a fringe projection system which is capable of measuring in very limited space. A Raspberry Pi 2 is used to generate the projection patterns, acquire the image and reconstruct the geometry. Together with a small LED projector, the measurement system is small and easy to handle. It consists of off-the-shelf products which are nonetheless capable of measuring with an uncertainty of less than 100 μ m . Full article
(This article belongs to the Special Issue Raspberry Pi Technology) Printed Edition available
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Open AccessFeature PaperArticle
A Multi-Modal Sensing Glove for Human Manual-Interaction Studies
Electronics 2016, 5(3), 42; https://doi.org/10.3390/electronics5030042
Received: 27 May 2016 / Revised: 13 July 2016 / Accepted: 15 July 2016 / Published: 20 July 2016
Cited by 8 | Viewed by 2686 | PDF Full-text (20593 KB) | HTML Full-text | XML Full-text
Abstract
We present an integrated sensing glove that combines two of the most visionary wearable sensing technologies to provide both hand posture sensing and tactile pressure sensing in a unique, lightweight, and stretchable device. Namely, hand posture reconstruction employs Knitted Piezoresistive Fabrics that allows [...] Read more.
We present an integrated sensing glove that combines two of the most visionary wearable sensing technologies to provide both hand posture sensing and tactile pressure sensing in a unique, lightweight, and stretchable device. Namely, hand posture reconstruction employs Knitted Piezoresistive Fabrics that allows us to measure bending. From only five of these sensors (one for each finger) the full hand pose of a 19 degrees of freedom (DOF) hand model is reconstructed leveraging optimal sensor placement and estimation techniques. To this end, we exploit a-priori information of synergistic coordination patterns in grasping tasks. Tactile sensing employs a piezoresistive fabric allowing us to measure normal forces in more than 50 taxels spread over the palmar surface of the glove. We describe both sensing technologies, report on the software integration of both modalities, and describe a preliminary evaluation experiment analyzing hand postures and force patterns during grasping. Results of the reconstruction are promising and encourage us to push further our approach with potential applications in neuroscience, virtual reality, robotics and tele-operation. Full article
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Open AccessArticle
Analysis and Design of a DSTATCOM Based on Sliding Mode Control Strategy for Improvement of Voltage Sag in Distribution Systems
Electronics 2016, 5(3), 41; https://doi.org/10.3390/electronics5030041
Received: 20 June 2016 / Revised: 9 July 2016 / Accepted: 13 July 2016 / Published: 20 July 2016
Cited by 10 | Viewed by 1784 | PDF Full-text (1784 KB) | HTML Full-text | XML Full-text
Abstract
Voltage sag is considered to be the most serious problem of power quality. It is caused by faults in the power system or by the starting of large induction motors. Voltage sag causes about 80% of the power quality problems in power systems. [...] Read more.
Voltage sag is considered to be the most serious problem of power quality. It is caused by faults in the power system or by the starting of large induction motors. Voltage sag causes about 80% of the power quality problems in power systems. One of the main reasons for voltage sag is short circuit fault, which can be compensated for by a distribution static compensator (DSTATCOM) as an efficient and economical flexible AC transmission system (FACTS) device. In this paper, compensation of this voltage sag using DSTATCOM is reviewed, in which a sliding mode control (SMC) technique is employed. The results of this control system are compared with a P+Resonant control system. It will be shown that this control system is able to compensate the voltage sag over a broader range compared to other common control systems. Simulation results are obtained using PSCAD/EMTDC software and compared to that of a similar method. Full article
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Open AccessReview
Cyber-Physical System Security of a Power Grid: State-of-the-Art
Electronics 2016, 5(3), 40; https://doi.org/10.3390/electronics5030040
Received: 26 April 2016 / Revised: 28 June 2016 / Accepted: 8 July 2016 / Published: 14 July 2016
Cited by 17 | Viewed by 3181 | PDF Full-text (2544 KB) | HTML Full-text | XML Full-text
Abstract
As part of the smart grid development, more and more technologies are developed and deployed on the power grid to enhance the system reliability. A primary purpose of the smart grid is to significantly increase the capability of computer-based remote control and automation. [...] Read more.
As part of the smart grid development, more and more technologies are developed and deployed on the power grid to enhance the system reliability. A primary purpose of the smart grid is to significantly increase the capability of computer-based remote control and automation. As a result, the level of connectivity has become much higher, and cyber security also becomes a potential threat to the cyber-physical systems (CPSs). In this paper, a survey of the state-of-the-art is conducted on the cyber security of the power grid concerning issues of: (1) the structure of CPSs in a smart grid; (2) cyber vulnerability assessment; (3) cyber protection systems; and (4) testbeds of a CPS. At Washington State University (WSU), the Smart City Testbed (SCT) has been developed to provide a platform to test, analyze and validate defense mechanisms against potential cyber intrusions. A test case is provided in this paper to demonstrate how a testbed helps the study of cyber security and the anomaly detection system (ADS) for substations. Full article
(This article belongs to the Special Issue Smart Grid Cyber Security)
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Open AccessArticle
A Galvanic Coupling Method for Assessing Hydration Rates
Electronics 2016, 5(3), 39; https://doi.org/10.3390/electronics5030039
Received: 30 May 2016 / Revised: 28 June 2016 / Accepted: 1 July 2016 / Published: 13 July 2016
Cited by 8 | Viewed by 1994 | PDF Full-text (1380 KB) | HTML Full-text | XML Full-text
Abstract
Recent advances in biomedical sensors, data acquisition techniques, microelectronics and wireless communication systems opened up the use of wearable technology for ehealth monitoring. We introduce a galvanic coupled intrabody communication for monitoring human body hydration. Studies in hydration provide the information necessary for [...] Read more.
Recent advances in biomedical sensors, data acquisition techniques, microelectronics and wireless communication systems opened up the use of wearable technology for ehealth monitoring. We introduce a galvanic coupled intrabody communication for monitoring human body hydration. Studies in hydration provide the information necessary for understanding the desired fluid levels for optimal performance of the body’s physiological and metabolic processes during exercise and activities of daily living. Current measurement techniques are mostly suitable for laboratory purposes due to their complexity and technical requirements. Less technical methods such as urine color observation and skin turgor testing are subjective and cannot be integrated into a wearable device. Bioelectrical impedance methods are popular but mostly used for estimating total body water with limited accuracy and sensitive to 800 mL–1000 mL change in body fluid levels. We introduce a non-intrusive and simple method of tracking hydration rates that can detect up to 1.30 dB reduction in attenuation when as little as 100 mL of water is consumed. Our results show that galvanic coupled intrabody signal propagation can provide qualitative hydration and dehydration rates in line with changes in an individual’s urine specific gravity and body mass. The real-time changes in galvanic coupled intrabody signal attenuation can be integrated into wearable electronic devices to evaluate body fluid levels on a particular area of interest and can aid diagnosis and treatment of fluid disorders such as lymphoedema. Full article
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Open AccessArticle
Analysis of In-to-Out Wireless Body Area Network Systems: Towards QoS-Aware Health Internet of Things Applications
Electronics 2016, 5(3), 38; https://doi.org/10.3390/electronics5030038
Received: 6 April 2016 / Revised: 4 July 2016 / Accepted: 6 July 2016 / Published: 13 July 2016
Cited by 7 | Viewed by 2665 | PDF Full-text (4185 KB) | HTML Full-text | XML Full-text
Abstract
In this paper, an analytical and accurate in-to-out (I2O) human body path loss (PL) model at 2.45 GHz is derived based on a 3D heterogeneous human body model under safety constraints. The bit error rate (BER) performance for this channel using multiple efficient [...] Read more.
In this paper, an analytical and accurate in-to-out (I2O) human body path loss (PL) model at 2.45 GHz is derived based on a 3D heterogeneous human body model under safety constraints. The bit error rate (BER) performance for this channel using multiple efficient modulation schemes is investigated and the link budget is analyzed based on a predetermined satisfactory BER of 10−3. In addition, an incremental relay-based cooperative quality of service-aware (QoS-aware) routing protocol for the proposed I2O WBAN is presented and compared with an existing scheme. Linear programming QoS metric expressions are derived and employed to maximize the network lifetime, throughput, minimizing delay. Results show that binary phase-shift keying (BPSK) outperforms other modulation techniques for the proposed I2O WBAN systems, enabling the support of a 30 Mbps data transmission rate up to 1.6 m and affording more reliable communication links when the transmitter power is increased. Moreover, the proposed incremental cooperative routing protocol outperforms the existing two-relay technique in terms of energy efficiency. Open issues and on-going research within the I2O WBAN area are presented and discussed as an inspiration towards developments in health IoT applications. Full article
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Open AccessArticle
Developing an Affordable and Portable Control Systems Laboratory Kit with a Raspberry Pi
Electronics 2016, 5(3), 36; https://doi.org/10.3390/electronics5030036
Received: 10 May 2016 / Revised: 26 June 2016 / Accepted: 27 June 2016 / Published: 4 July 2016
Cited by 2 | Viewed by 2844 | PDF Full-text (4311 KB) | HTML Full-text | XML Full-text | Supplementary Files
Abstract
Instructional laboratories are common in engineering programs. Instructional laboratories should evolve with technology and support the changes in higher education, like the increased popularity of online courses. In this study, an affordable and portable laboratory kit was designed to replace the expensive on-campus [...] Read more.
Instructional laboratories are common in engineering programs. Instructional laboratories should evolve with technology and support the changes in higher education, like the increased popularity of online courses. In this study, an affordable and portable laboratory kit was designed to replace the expensive on-campus equipment for two control systems courses. The complete kit costs under $135 and weighs under 0.68 kilograms. It is comprised of off-the-shelf components (e.g., Raspberry Pi, DC motor) and 3D printed parts. The kit has two different configurations. The first (base) configuration is a DC motor system with a position and speed sensor. The second configuration adds a Furuta inverted pendulum attachment with another position sensor. These configurations replicate most of the student learning outcomes for the two control systems courses for which they were designed. Full article
(This article belongs to the Special Issue Raspberry Pi Technology) Printed Edition available
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Open AccessArticle
Virtual Machine Replication on Achieving Energy-Efficiency in a Cloud
Electronics 2016, 5(3), 37; https://doi.org/10.3390/electronics5030037
Received: 1 June 2016 / Revised: 22 June 2016 / Accepted: 27 June 2016 / Published: 1 July 2016
Cited by 5 | Viewed by 1684 | PDF Full-text (1013 KB) | HTML Full-text | XML Full-text
Abstract
The rapid growth in cloud service demand has led to the establishment of large-scale virtualized data centers in which virtual machines (VMs) are used to handle user requests for service. A user’s request cannot be completed if the VM fails. Replication mechanisms can [...] Read more.
The rapid growth in cloud service demand has led to the establishment of large-scale virtualized data centers in which virtual machines (VMs) are used to handle user requests for service. A user’s request cannot be completed if the VM fails. Replication mechanisms can be used to mitigate the impact of failures. Further, data centers consume a large amount of energy resulting in high operating costs and contributing to significant greenhouse gas (GHG) emissions. In this paper, we focus on Infrastructure as a Service (IaaS) cloud where user job requests are processed by VMs and analyze the effectiveness of VM replications in terms of job completion time performance as well as energy consumption. Three different schemes: cold, warm, and hot replications are considered. The trade-offs between job completion time and energy consumption in different replication schemes are characterized through comprehensive analytical models which capture VM state transitions and associated power consumption patterns. The effectiveness of replication schemes are demonstrated through experimental results. To verify the validity of the proposed analytical models, we extend the widely used cloud simulator CloudSim and compare the simulation results with analytical solutions. Full article
(This article belongs to the Special Issue Energy Saving in Data Centers)
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Open AccessArticle
Erica the Rhino: A Case Study in Using Raspberry Pi Single Board Computers for Interactive Art
Electronics 2016, 5(3), 35; https://doi.org/10.3390/electronics5030035
Received: 4 May 2016 / Revised: 17 June 2016 / Accepted: 24 June 2016 / Published: 30 June 2016
Cited by 2 | Viewed by 2352 | PDF Full-text (18738 KB) | HTML Full-text | XML Full-text
Abstract
Erica the Rhino is an interactive art exhibit created by the University of Southampton, UK. Erica was created as part of a city wide art trail in 2013 called “Go! Rhinos”, curated by Marwell Wildlife, to raise awareness of Rhino conservation. Erica [...] Read more.
Erica the Rhino is an interactive art exhibit created by the University of Southampton, UK. Erica was created as part of a city wide art trail in 2013 called “Go! Rhinos”, curated by Marwell Wildlife, to raise awareness of Rhino conservation. Erica arrived as a white fibreglass shell which was then painted and equipped with five Raspberry Pi Single Board Computers (SBC). These computers allowed the audience to interact with Erica through a range of sensors and actuators. In particular, the audience could feed and stroke her to prompt reactions, as well as send her Tweets to change her behaviour. Pi SBCs were chosen because of their ready availability and their educational pedigree. During the deployment, ‘coding clubs’ were run in the shopping centre where Erica was located, and these allowed children to experiment with and program the same components used in Erica. The experience gained through numerous deployments around the country has enabled Erica to be upgraded to increase reliability and ease of maintenance, whilst the release of the Pi 2 has allowed her responsiveness to be improved. Full article
(This article belongs to the Special Issue Raspberry Pi Technology) Printed Edition available
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Open AccessArticle
Multi-Robot Deployment Using a Virtual Force Approach: Challenges and Guidelines
Electronics 2016, 5(3), 34; https://doi.org/10.3390/electronics5030034
Received: 30 January 2016 / Revised: 10 May 2016 / Accepted: 17 June 2016 / Published: 29 June 2016
Cited by 2 | Viewed by 1191 | PDF Full-text (5989 KB) | HTML Full-text | XML Full-text
Abstract
Robotics networks are an emerging technology that has a wide range of applications. Robots are used for many military and civilian applications. Applications such as search-and-rescue operations or area monitoring during an environmental disaster, cannot be effectively carried out by a single robot, [...] Read more.
Robotics networks are an emerging technology that has a wide range of applications. Robots are used for many military and civilian applications. Applications such as search-and-rescue operations or area monitoring during an environmental disaster, cannot be effectively carried out by a single robot, but rather are carried out by several robots forming what is called a “robotic network”. In rescue operations, for example, robots can be used to help to discover bodies under the rubble or even to assist the injured. One of the main challenges in these applications is how to deploy the robots without central coordination. Virtual force (VF) technique appears to be one of the prominent approaches to perform multi-robot deployment autonomously. However, the effectiveness of this approach depends on how its parameters are calibrated in order to achieve the required deployment. There are two important factors: attractive force ( w a ) and repulsive force ( w r ). In this work, we investigate the best settings of these two factors in order to accommodate different kinds of scenarios. Additionally, and for the first time, an energy-aware virtual force approach is proposed to balance energy consumption among deployed robots and consequently maximize the network lifetime. Extensive simulation experiments are conducted to study and explore the effectiveness of the proposed settings. Finally, a proof of concept experiment using LegoTM Mindstorm robots is carried out to demonstrate the effectiveness of these settings. Full article
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Open AccessFeature PaperArticle
Educational Programming on the Raspberry Pi
Electronics 2016, 5(3), 33; https://doi.org/10.3390/electronics5030033
Received: 3 May 2016 / Revised: 16 June 2016 / Accepted: 16 June 2016 / Published: 24 June 2016
Cited by 8 | Viewed by 2473 | PDF Full-text (3611 KB) | HTML Full-text | XML Full-text
Abstract
The original aim when creating the Raspberry Pi was to encourage “kids”—pre-university learners—to engage with programming, and to develop an interest in and understanding of programming and computer science concepts. The method to achieve this was to give them their own, low cost [...] Read more.
The original aim when creating the Raspberry Pi was to encourage “kids”—pre-university learners—to engage with programming, and to develop an interest in and understanding of programming and computer science concepts. The method to achieve this was to give them their own, low cost computer that they could use to program on, as a replacement for a family PC that often did not allow this option. With the original release, the Raspberry Pi included two programming environments in the standard distribution software: Scratch and IDLE, a Python environment. In this paper, we describe two programming environments that we developed and recently ported and optimised for the Raspberry Pi, Greenfoot and BlueJ, both using the Java programming language. Greenfoot and BlueJ are both now included in the Raspberry Pi standard software distribution, and they differ in many respects from IDLE; they are more graphical, more interactive, more engaging, and illustrate concepts of object orientation more clearly. Thus, they have the potential to support the original aim of the Raspberry Pi by creating a deeper engagement with programming. This paper describes these two environments and how they may be used, and discusses their differences and relationships to the two previously available systems. Full article
(This article belongs to the Special Issue Raspberry Pi Technology) Printed Edition available
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Open AccessArticle
Benefits of Considering More than Temperature Acceleration for GaN HEMT Life Testing
Electronics 2016, 5(3), 32; https://doi.org/10.3390/electronics5030032
Received: 13 April 2016 / Revised: 2 June 2016 / Accepted: 16 June 2016 / Published: 23 June 2016
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Abstract
The purpose of this work was to investigate the validity of Arrhenius accelerated-life testing when applied to gallium nitride (GaN) high electron mobility transistors (HEMT) lifetime assessments, where the standard assumption is that only critical stressor is temperature, which is derived from operating [...] Read more.
The purpose of this work was to investigate the validity of Arrhenius accelerated-life testing when applied to gallium nitride (GaN) high electron mobility transistors (HEMT) lifetime assessments, where the standard assumption is that only critical stressor is temperature, which is derived from operating power, device channel-case, thermal resistance, and baseplate temperature. We found that power or temperature alone could not explain difference in observed degradation, and that accelerated life tests employed by industry can benefit by considering the impact of accelerating factors besides temperature. Specifically, we found that the voltage used to reach a desired power dissipation is important, and also that temperature acceleration alone or voltage alone (without much power dissipation) is insufficient to assess lifetime at operating conditions. Full article
(This article belongs to the Special Issue Gallium Nitride Electronics)
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