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Electronics, Volume 3, Issue 3 (September 2014), Pages 398-563

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Research

Jump to: Review

Open AccessArticle A Low Latency Electrocardiographic QRS Activity Recovery Technique for Use on the Upper Left Arm
Electronics 2014, 3(3), 409-418; doi:10.3390/electronics3030409
Received: 20 February 2014 / Revised: 5 May 2014 / Accepted: 29 June 2014 / Published: 16 July 2014
Cited by 1 | PDF Full-text (362 KB) | HTML Full-text | XML Full-text
Abstract
Empirical mode decomposition is used as a low latency method of recovering the cardiac ventricular activity QRS biopotential signals recorded from the upper arm. The recovery technique is tested and compared with the industry accepted technique of signal averaging using a database [...] Read more.
Empirical mode decomposition is used as a low latency method of recovering the cardiac ventricular activity QRS biopotential signals recorded from the upper arm. The recovery technique is tested and compared with the industry accepted technique of signal averaging using a database of “normal” rhythm traces from bipolar ECG leads along the left arm, recorded from patient volunteers at a cardiology day procedure clinic. The same partial recomposition technique is applied to recordings taken using an innovative dry electrode technology supplied by Plessey Semiconductors. In each case, signal to noise ratio (SNR) is used as a metric for comparison. Full article
(This article belongs to the Special Issue Wearable Electronics)
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Open AccessArticle Radiation Pattern Measurement of a Low-Profile Wearable Antenna Using an Optical Fibre and a Solid Anthropomorphic Phantom
Electronics 2014, 3(3), 462-473; doi:10.3390/electronics3030462
Received: 28 March 2014 / Revised: 23 June 2014 / Accepted: 27 June 2014 / Published: 5 August 2014
Cited by 1 | PDF Full-text (1196 KB) | HTML Full-text | XML Full-text
Abstract
This paper presents a study into radiation pattern measurements of an electrically small dielectric resonator antenna (DRA) operating between 2.4 and 2.5 GHz in the industrial, scientific and medical (ISM) radio band for body-centric wireless communication applications. To eliminate the distortion of [...] Read more.
This paper presents a study into radiation pattern measurements of an electrically small dielectric resonator antenna (DRA) operating between 2.4 and 2.5 GHz in the industrial, scientific and medical (ISM) radio band for body-centric wireless communication applications. To eliminate the distortion of the radiation pattern associated with the unwanted radiation from a metallic coaxial cable feeding the antenna we have replaced it with a fibre optic feed and an electro-optical (EO) transducer. The optical signal is then converted back to RF using an Opto-Electric Field Sensor (OEFS) system. To ensure traceable measurements of the radiation pattern performance of the wearable antenna a generic head and torso solid anthropomorphic phantom model has been employed. Furthermore, to illustrate the benefits of the method, numerical simulations of the co-polar and cross-polar H-plane radiation patterns at 2.4, 2.45, and 2.5 GHz are compared with the measured results obtained using: (i) an optical fibre; and (ii) a metallic coaxial cable. Full article
(This article belongs to the Special Issue Wearable Electronics)
Open AccessArticle Investigation of a Switchable Textile Communication System on the Human Body
Electronics 2014, 3(3), 491-503; doi:10.3390/electronics3030491
Received: 13 February 2014 / Revised: 4 June 2014 / Accepted: 14 July 2014 / Published: 18 August 2014
Cited by 1 | PDF Full-text (1268 KB) | HTML Full-text | XML Full-text
Abstract
In this paper, a switchable textile communication system working at 2.45 GHz ISM band is presented and studied for different locations within a realistic on-body environment. A 3D laser scanner is used to generate a numerical phantom of the measured subject to [...] Read more.
In this paper, a switchable textile communication system working at 2.45 GHz ISM band is presented and studied for different locations within a realistic on-body environment. A 3D laser scanner is used to generate a numerical phantom of the measured subject to improve the accuracy of the simulations which are carried out for different body postures. For the off-body communications, the system is acting as an aperture coupled microstrip patch antenna with a boresight gain of 1.48 dBi. On-body communication is achieved by using a textile stripline, which gives approximately 5 dB transmission loss over 600 mm distance. The system is switched between on and off-body modes by PIN diodes. Common issues, such as shape distortion and body detuning effects which the textile antenna may experience in realistic use are fully discussed. Robust antenna performance is noted in the on-body tests, and an additional 3 dB transmission coefficient deduction was noticed in the most severe shape distortion case. Full article
(This article belongs to the Special Issue Wearable Electronics)
Open AccessArticle A Novel Geo-Broadcast Algorithm for V2V Communications over WSN
Electronics 2014, 3(3), 521-537; doi:10.3390/electronics3030521
Received: 31 March 2014 / Revised: 8 July 2014 / Accepted: 16 July 2014 / Published: 28 August 2014
Cited by 2 | PDF Full-text (5525 KB) | HTML Full-text | XML Full-text
Abstract
The key for enabling the next generation of advanced driver assistance systems (ADAS), the cooperative systems, is the availability of vehicular communication technologies, whose mandatory installation in cars is foreseen in the next few years. The definition of the communications is in [...] Read more.
The key for enabling the next generation of advanced driver assistance systems (ADAS), the cooperative systems, is the availability of vehicular communication technologies, whose mandatory installation in cars is foreseen in the next few years. The definition of the communications is in the final step of development, with great efforts on standardization and some field operational tests of network devices and applications. However, some inter-vehicular communications issues are not sufficiently developed and are the target of research. One of these challenges is the construction of stable networks based on the position of the nodes of the vehicular network, as well as the broadcast of information destined to nodes concentrated in a specific geographic area without collapsing the network. In this paper, a novel algorithm for geo-broadcast communications is presented, based on the evolution of previous results in vehicular mesh networks using wireless sensor networks with IEEE 802.15.4 technology. This algorithm has been designed and compared with the IEEE 802.11p algorithms, implemented and validated in controlled conditions and tested on real vehicles. The results suggest that the characteristics of the designed broadcast algorithm can improve any vehicular communications architecture to complement a geo-networking functionality that supports a variety of ADAS. Full article
(This article belongs to the Special Issue Connected Vehicles, V2V Communications, and VANET)
Open AccessArticle Optimal Power Allocation for MIMO-MAC in Cognitive Radio Networks
Electronics 2014, 3(3), 538-552; doi:10.3390/electronics3030538
Received: 15 May 2014 / Revised: 12 August 2014 / Accepted: 12 August 2014 / Published: 12 September 2014
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Abstract
This paper considers a cognitive radio (CR) network, in which the unlicensed (secondary) users (SUs) are allowed to concurrently access the spectrum allocated to the licensed (primary) users, provided that the interference of SUs with the primary users (PUs) satisfies certain constraints. [...] Read more.
This paper considers a cognitive radio (CR) network, in which the unlicensed (secondary) users (SUs) are allowed to concurrently access the spectrum allocated to the licensed (primary) users, provided that the interference of SUs with the primary users (PUs) satisfies certain constraints. It is more general and owns a stronger challenge to ensure the quality of service (QoS) of PUs, as well as to maximize the sum-rate of SUs. On the other hand, the multiple-antenna mobile user case has not been well investigated for the target problem in the open literature. We refer to this setting as multiple input multiple output multiple access channels (MIMO-MAC) in the CR network. Subject to the interference constraints of SUs and the peak power constraints of SUs, the sum-rate maximization problem is solved. To efficiently maximize the achievable sum-rate of SUs, a tight pair of upper and lower bounds, as an interval, of the optimal Lagrange multiplier is proposed. It can avoid ineffectiveness or inefficiency when the dual decomposition is used. Furthermore, a novel water-filling-like algorithm is proposed for the inner loop computation of the proposed problem. It is shown that this algorithm used in the inner loop computation can obtain the exact solution with a few finite computations, to avoid one more loop, which would be embedded in the inner loop. In addition, the proposed approach overcomes the limitation of Hermitian matrices, as optimization variables. This limitation to the optimization problem in several complex variables has not been well investigated so far. As a result, our analysis and results are solidly extended to the field of complex numbers, which are more compatible with practical communication systems. Full article
(This article belongs to the Special Issue Cognitive Radio: Use the Spectrum in a More Efficient Way)
Open AccessArticle Cognitive Spectrum Sensing with Multiple Primary Users in Rayleigh Fading Channels
Electronics 2014, 3(3), 553-563; doi:10.3390/electronics3030553
Received: 27 May 2014 / Revised: 3 September 2014 / Accepted: 12 September 2014 / Published: 23 September 2014
Cited by 2 | PDF Full-text (281 KB) | HTML Full-text | XML Full-text
Abstract
Accurate detection of white spaces is crucial in cognitive radio networks. Initial investigations show that the accurate detection in a multiple primary users environment is challenging, especially under severe multipath conditions. Among many techniques, recently proposed eigenvalue-based detectors that use random matrix [...] Read more.
Accurate detection of white spaces is crucial in cognitive radio networks. Initial investigations show that the accurate detection in a multiple primary users environment is challenging, especially under severe multipath conditions. Among many techniques, recently proposed eigenvalue-based detectors that use random matrix theories to eliminate the need of prior knowledge of the signals proved to be a solid approach. In this work, we study the effect of Rayleigh multipath fading channels on spectrum sensing in a multiple primary user environment for a pre-proposed detector called the spherical detector using the eigenvalue approach. Simulation results show interesting outcomes. Full article
(This article belongs to the Special Issue Cognitive Radio: Use the Spectrum in a More Efficient Way)
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Review

Jump to: Research

Open AccessReview A Compact Dual-Mode Wearable Antenna for Body-Centric Wireless Communications
Electronics 2014, 3(3), 398-408; doi:10.3390/electronics3030398
Received: 20 February 2014 / Revised: 3 May 2014 / Accepted: 22 May 2014 / Published: 1 July 2014
Cited by 2 | PDF Full-text (1303 KB) | HTML Full-text | XML Full-text
Abstract
The miniaturization of electronic devices is leading to the creation of body-centric wireless communications (BCWCs), in which wireless devices are attached to the human body. In particular, personal healthcare is considered as the biggest potential application. In this paper, we propose a [...] Read more.
The miniaturization of electronic devices is leading to the creation of body-centric wireless communications (BCWCs), in which wireless devices are attached to the human body. In particular, personal healthcare is considered as the biggest potential application. In this paper, we propose a compact wearable dual-mode (on-body and off-body modes) antenna for personal healthcare systems. For on-body mode at 10 MHz, received voltages are analyzed with a chest phantom, while for the off-body mode in the 2.4 GHz ISM band, reflection coefficient (S11) and radiation patterns are studied. Full article
(This article belongs to the Special Issue Wearable Electronics)
Open AccessReview Multicarrier Spread Spectrum Modulation Schemes and Efficient FFT Algorithms for Cognitive Radio Systems
Electronics 2014, 3(3), 419-443; doi:10.3390/electronics3030419
Received: 17 May 2014 / Revised: 2 July 2014 / Accepted: 4 July 2014 / Published: 17 July 2014
PDF Full-text (382 KB) | HTML Full-text | XML Full-text
Abstract
Spread spectrum (SS) and multicarrier modulation (MCM) techniques are recognized as potential candidates for the design of underlay and interweave cognitive radio (CR) systems, respectively. Direct Sequence Code Division Multiple Access (DS-CDMA) is a spread spectrum technique generally used in underlay CR [...] Read more.
Spread spectrum (SS) and multicarrier modulation (MCM) techniques are recognized as potential candidates for the design of underlay and interweave cognitive radio (CR) systems, respectively. Direct Sequence Code Division Multiple Access (DS-CDMA) is a spread spectrum technique generally used in underlay CR systems. Orthogonal Frequency Division Multiplexing (OFDM) is the basic MCM technique, primarily used in interweave CR systems. There are other MCM schemes derived from OFDM technique, like Non-Contiguous OFDM, Spread OFDM, and OFDM-OQAM, which are more suitable for CR systems. Multicarrier Spread Spectrum Modulation (MCSSM) schemes like MC-CDMA, MC-DS-CDMA and SS-MC-CDMA, combine DS-CDMA and OFDM techniques in order to improve the CR system performance and adaptability. This article gives a detailed survey of the various spread spectrum and multicarrier modulation schemes proposed in the literature. Fast Fourier Transform (FFT) plays a vital role in all the multicarrier modulation techniques. The FFT part of the modem can be used for spectrum sensing. The performance of the FFT operator plays a crucial role in the overall performance of the system. Since the cognitive radio is an adaptive system, the FFT operator must also be adaptive for various input/output values, in order to save energy and time taken for execution. This article also includes the various efficient FFT algorithms proposed in the literature, which are suitable for CR systems. Full article
(This article belongs to the Special Issue Cognitive Radio: Use the Spectrum in a More Efficient Way)
Open AccessReview Bio-Organic Electronics—Overview and Prospects for the Future
Electronics 2014, 3(3), 444-461; doi:10.3390/electronics3030444
Received: 8 March 2014 / Revised: 10 June 2014 / Accepted: 7 July 2014 / Published: 18 July 2014
Cited by 11 | PDF Full-text (6495 KB) | HTML Full-text | XML Full-text
Abstract
In recent years, both biodegradable and bio-based electronics have attracted increasing interest, but are also controversially discussed at the same time. Yet, it is not clear whether they will contribute to science and technology or whether they will disappear without major impact. [...] Read more.
In recent years, both biodegradable and bio-based electronics have attracted increasing interest, but are also controversially discussed at the same time. Yet, it is not clear whether they will contribute to science and technology or whether they will disappear without major impact. The present review will address several aspects while showing the potential opportunities of bio-organic electronics. An overview about the complex terminology of this emerging field is given and test methods are presented which are used to evaluate the biodegradable properties. It will be shown that the majority of components of organic electronics can be substituted by biodegradable or bio-based materials. Moreover, application scenarios are presented where bio-organic materials have advantages compared to conventional ones. A variety of publications are highlighted which encompass typical organic devices like organic light emitting diodes, organic solar cells and organic thin film transistors as well as applications in the field of medicine or agriculture. Full article
(This article belongs to the Special Issue Organic Semiconductors) Print Edition available
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Open AccessReview Compact, Wearable Antennas for Battery-Less Systems Exploiting Fabrics and Magneto-Dielectric Materials
Electronics 2014, 3(3), 474-490; doi:10.3390/electronics3030474
Received: 7 March 2014 / Revised: 30 April 2014 / Accepted: 25 July 2014 / Published: 18 August 2014
Cited by 2 | PDF Full-text (2398 KB) | HTML Full-text | XML Full-text
Abstract
In this paper, we describe some promising solutions to the modern need for wearable, energy-aware, miniaturized, wireless systems, whose typical envisaged application is a body area network (BAN). To reach this goal, novel materials are adopted, such as fabrics, in place of [...] Read more.
In this paper, we describe some promising solutions to the modern need for wearable, energy-aware, miniaturized, wireless systems, whose typical envisaged application is a body area network (BAN). To reach this goal, novel materials are adopted, such as fabrics, in place of standard substrates and metallizations, which require a systematic procedure for their electromagnetic characterization. Indeed, the design of such sub-systems represents a big issue, since approximate approaches could result in strong deviations from the actual system performance. To face this problem, we demonstrate our design procedure, which is based on the concurrent use of electromagnetic software tools and nonlinear circuit-level techniques, able to simultaneously predict the actual system behavior of an antenna system, consisting of the radiating and of the nonlinear blocks, at the component level. This approach is demonstrated for the design of a fully-wearable tri-band rectifying antenna (rectenna) and of a button-shaped, electrically-small antenna deploying a novel magneto-dielectric substrate. Simulations are supported by measurements, both in terms of antenna port parameters and far-field results. Full article
(This article belongs to the Special Issue Wearable Electronics)
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Open AccessReview Wearable Wireless Cardiovascular Monitoring Using Textile-Based Nanosensor and Nanomaterial Systems
Electronics 2014, 3(3), 504-520; doi:10.3390/electronics3030504
Received: 17 April 2014 / Revised: 5 July 2014 / Accepted: 8 July 2014 / Published: 19 August 2014
Cited by 6 | PDF Full-text (4974 KB) | HTML Full-text | XML Full-text
Abstract
Wearable and ultraportable electronics coupled with pervasive computing are poised to revolutionize healthcare services delivery. The potential cost savings in both treatment, as well as preventive care are the focus of several research efforts across the globe. In this review, we describe [...] Read more.
Wearable and ultraportable electronics coupled with pervasive computing are poised to revolutionize healthcare services delivery. The potential cost savings in both treatment, as well as preventive care are the focus of several research efforts across the globe. In this review, we describe the motivations behind wearable solutions to real-time cardiovascular monitoring from a perspective of current healthcare services, as well as from a systems design perspective. We identify areas where emerging research is underway, namely: nanotechnology in textile-based wearable monitors and healthcare solutions targeted towards smart devices, like smartphones and tablets. Full article
(This article belongs to the Special Issue Wearable Electronics)

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