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Volume 6
Issue 2
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Electronics, Volume 6, Issue 2 (June 2017) – 24 articles

Cover Story (view full-size image): RFID Antennas with asymmetric detection patterns can be used to determine the location of people carrying tags in social robotics applications. Social robotics is increasingly accounting for the significance of the areas around social entities. For a robot, being able to detect the position of someone that is in its close neighborhood means that it can adapt its behavior and improve the quality of the interactions with humans. The image shows a probabilistic model of the detection pattern for a system in the band 902-928 MHz (detection probability increasing with the temperature of the color). Detection probabilities can be estimated in realtime from the read counts and matched with these diagrams to obtain estimates of the position of the tags. View the paper here.
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1421 KiB  
Article
Design And Implementation of Low Area/Power Elliptic Curve Digital Signature Hardware Core
by Anissa Sghaier, Medien Zeghid, Chiraz Massoud and Mohsen Mahchout
Electronics 2017, 6(2), 46; https://doi.org/10.3390/electronics6020046 - 19 Jun 2017
Cited by 27 | Viewed by 7694
Abstract
The Elliptic Curve Digital Signature Algorithm(ECDSA) is the analog to the Digital Signature Algorithm(DSA). Based on the elliptic curve, which uses a small key compared to the others public-key algorithms, ECDSA is the most suitable scheme for environments where processor power and storage [...] Read more.
The Elliptic Curve Digital Signature Algorithm(ECDSA) is the analog to the Digital Signature Algorithm(DSA). Based on the elliptic curve, which uses a small key compared to the others public-key algorithms, ECDSA is the most suitable scheme for environments where processor power and storage are limited. This paper focuses on the hardware implementation of the ECDSA over elliptic curveswith the 163-bit key length recommended by the NIST (National Institute of Standards and Technology). It offers two services: signature generation and signature verification. The proposed processor integrates an ECC IP, a Secure Hash Standard 2 IP (SHA-2 Ip) and Random Number Generator IP (RNG IP). Thus, all IPs will be optimized, and different types of RNG will be implemented in order to choose the most appropriate one. A co-simulation was done to verify the ECDSA processor using MATLAB Software. All modules were implemented on a Xilinx Virtex 5 ML 50 FPGA platform; they require respectively 9670 slices, 2530 slices and 18,504 slices. FPGA implementations represent generally the first step for obtaining faster ASIC implementations. Further, the proposed design was also implemented on an ASIC CMOS 45-nm technology; it requires a 0.257 mm2 area cell achieving a maximum frequency of 532 MHz and consumes 63.444 (mW). Furthermore, in this paper, we analyze the security of our proposed ECDSA processor against the no correctness check for input points and restart attacks. Full article
(This article belongs to the Special Issue Cryptographic Hardware for Embedded Systems)
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2798 KiB  
Article
Security Interrogation and Defense for SAR Analog to Digital Converter
by Shayan Taheri, Jie Lin and Jiann-Shiun Yuan
Electronics 2017, 6(2), 48; https://doi.org/10.3390/electronics6020048 - 17 Jun 2017
Cited by 10 | Viewed by 6574
Abstract
Nowadays, the analog and mixed-signal intellectual property (IP) cores play an important role in system on chip (SoC) design due to their capabilities in performing critical functions. These IPs can be the target of adversaries similar to their digital counterparts. In this work, [...] Read more.
Nowadays, the analog and mixed-signal intellectual property (IP) cores play an important role in system on chip (SoC) design due to their capabilities in performing critical functions. These IPs can be the target of adversaries similar to their digital counterparts. In this work, we study the security aspects of a tunnel field effect transistor (TFET)-based six-bit successive approximation register (SAR) analog to digital converter (ADC) through proposing two threats and two countermeasures that target the output signals of the ADC datapath and its control unit. The datapath-based threat manipulates the exiting signals from the register file, and its countermeasure attempts to filter the ADC output based on the convention of having ± 1 least significant bit variation (at maximum) between the adjacent sampled data points. The control-based threat manipulates the exiting signals from the control unit, and its countermeasure is a trustworthy replication of a part of the ADC circuit that is used to provide reference data for security examination and output filtering. Full article
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1391 KiB  
Article
A Galvanic Intrabody Method for Assessing Fluid Flow in Unilateral Lymphoedema
by Clement Ogugua Asogwa, Johanis Aryo Bay, Patrick Mclaughlin, Stephen F. Collins and Daniel T. H. Lai
Electronics 2017, 6(2), 47; https://doi.org/10.3390/electronics6020047 - 15 Jun 2017
Cited by 2 | Viewed by 5259
Abstract
Lymphoedema is a disease associated with abnormal functioning of the lymph that leads to swelling of the body due to accumulation of tissue fluid on the affected area. Tissue fluid contains ions and electrolytes that affect electrical conductivity. The flow of tissue fluid [...] Read more.
Lymphoedema is a disease associated with abnormal functioning of the lymph that leads to swelling of the body due to accumulation of tissue fluid on the affected area. Tissue fluid contains ions and electrolytes that affect electrical conductivity. The flow of tissue fluid helps to distribute vital nutrients and other important elements necessary for healthy living. When tissue fluid is stagnated, a high concentration of electrolytes accumulate on the affected area, which in turn affects an electrical signal passing through that area to be minimally attenuated in relation to a free-flowing fluid. We demonstrate that a galvanic coupled signal propagating along a lymphoedema affected limb could capture these changes by the amount of attenuation the propagating signal experiences in time. Our results show that average rate of signal attenuation on a lymphoedema affected part of the body could be as slow as 0.16 dB/min, while the rate of signal attenuation on a healthy part is as high as 1.83 dB/min. This means that fluid accumulation could slow down the exchange of body electrolytes up to twice less the rate on an unaffected contralateral part of the body. Monitoring these changes by observing the average rate of change of a galvanic coupled signal attenuation on the affected body part can be used for diagnosing early developments of oedema in the body and for evaluating recovery in response to treatment procedures. Full article
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2333 KiB  
Article
Remote System Update for System on Programmable Chip Based on Controller Area Network
by Lei Zhou, Qingxiang Liu, Bangji Wang, Peixin Yang, Xiangqiang Li and Jianqiong Zhang
Electronics 2017, 6(2), 45; https://doi.org/10.3390/electronics6020045 - 13 Jun 2017
Cited by 4 | Viewed by 6671
Abstract
In some application domains, using a download cable to update the system on a programmable chip (SoPC) is infeasible, which reduces the maintainability and flexibility of the system. Hence the remote system update (RSU) scheme is being studied. In this scheme, the serial [...] Read more.
In some application domains, using a download cable to update the system on a programmable chip (SoPC) is infeasible, which reduces the maintainability and flexibility of the system. Hence the remote system update (RSU) scheme is being studied. In this scheme, the serial configuration (EPCS) device involves a factory mode configuration image, which acts as the baseline, and an application mode configuration image, which is used for some specific functions. Specifically, a new application mode image is delivered through the controller area network (CAN) with the improved application layer protocol. Besides, the data flow and data check for transmitting a new image are constructed to combine the transmission reliability with efficiency. The boot sequence copying hardware configuration code and software configuration code is analyzed, and the advanced boot loader is carried out to specify boot address of the application mode image manually. Experiments have demonstrated the feasibility of updating and running a new application mode image, as well as rolling back into the factory mode image when no application mode image is available. This scheme applies a single CAN bus, which makes the system easy to construct and suitable for the field distributed control system. Full article
(This article belongs to the Special Issue Hardware and Architecture)
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6204 KiB  
Review
Recent Advances in Electronic and Optoelectronic Devices Based on Two-Dimensional Transition Metal Dichalcogenides
by Mingxiao Ye, Dongyan Zhang and Yoke Khin Yap
Electronics 2017, 6(2), 43; https://doi.org/10.3390/electronics6020043 - 2 Jun 2017
Cited by 79 | Viewed by 17823
Abstract
Two-dimensional transition metal dichalcogenides (2D TMDCs) offer several attractive features for use in next-generation electronic and optoelectronic devices. Device applications of TMDCs have gained much research interest, and significant advancement has been recorded. In this review, the overall research advancement in electronic and [...] Read more.
Two-dimensional transition metal dichalcogenides (2D TMDCs) offer several attractive features for use in next-generation electronic and optoelectronic devices. Device applications of TMDCs have gained much research interest, and significant advancement has been recorded. In this review, the overall research advancement in electronic and optoelectronic devices based on TMDCs are summarized and discussed. In particular, we focus on evaluating field effect transistors (FETs), photovoltaic cells, light-emitting diodes (LEDs), photodetectors, lasers, and integrated circuits (ICs) using TMDCs. Full article
(This article belongs to the Special Issue Two-Dimensional Electronics and Optoelectronics)
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494 KiB  
Article
On the Generality of Codebook Approach for Sensor-Based Human Activity Recognition
by Kimiaki Shirahama and Marcin Grzegorzek
Electronics 2017, 6(2), 44; https://doi.org/10.3390/electronics6020044 - 1 Jun 2017
Cited by 22 | Viewed by 6626
Abstract
With the recent spread of mobile devices equipped with different sensors, it is possible to continuously recognise and monitor activities in daily life. This sensor-based human activity recognition is formulated as sequence classification to categorise sequences of sensor values into appropriate activity classes. [...] Read more.
With the recent spread of mobile devices equipped with different sensors, it is possible to continuously recognise and monitor activities in daily life. This sensor-based human activity recognition is formulated as sequence classification to categorise sequences of sensor values into appropriate activity classes. One crucial problem is how to model features that can precisely represent characteristics of each sequence and lead to accurate recognition. It is laborious and/or difficult to hand-craft such features based on prior knowledge and manual investigation about sensor data. To overcome this, we focus on a feature learning approach that extracts useful features from a large amount of data. In particular, we adopt a simple but effective one, called codebook approach, which groups numerous subsequences collected from sequences into clusters. Each cluster centre is called a codeword and represents a statistically distinctive subsequence. Then, a sequence is encoded as a feature expressing the distribution of codewords. The extensive experiments on different recognition tasks for physical, mental and eye-based activities validate the effectiveness, generality and usability of the codebook approach. Full article
(This article belongs to the Special Issue Data Processing and Wearable Systems for Effective Human Monitoring)
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4851 KiB  
Article
Improved Cell Search for mmWave Cellular Networks Using Deterministic Scanning Algorithm with Directional Array Antenna
by Toan Khanh Vo Dai, Ozlem Kilic and Hang Liu
Electronics 2017, 6(2), 42; https://doi.org/10.3390/electronics6020042 - 26 May 2017
Cited by 2 | Viewed by 7151
Abstract
Millimeter Wave (mmWave) communication is considered as an enabling technology for the next generation of cellular networks because it offers much larger bandwidth and higher data rate than the current lower-frequency cellular systems to satisfy the exponential growth of mobile data demand. High [...] Read more.
Millimeter Wave (mmWave) communication is considered as an enabling technology for the next generation of cellular networks because it offers much larger bandwidth and higher data rate than the current lower-frequency cellular systems to satisfy the exponential growth of mobile data demand. High gain directional antennas are needed to overcome high propagation losses in mmWave bands. However, the reliance on highly directional antennas will result in a more complicated initial cell search procedure since both base station and mobile device have to look for each other over a large space to establish the link. This paper focuses on analyzing the performance of the directional cell search procedure where the base stations periodically transmit signals in a set of optimal directional patterns to scan the coverage area. The mobile terminals detect the signals from the base station using the Generalized Likelihood Ratio Test (GLRT). The results show that with an appropriate scanning scheme, the use of directional antennas can outperform their omnidirectional counterparts in terms of signal detection performance as well as total time required. Full article
(This article belongs to the Special Issue Smart Antennas and MIMO Communications)
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4916 KiB  
Article
Sensitivity Enhancement of a PPM Level Capacitive Moisture Sensor
by Lokesh Kumar, Tarikul Islam and Subhas Chandra Mukhopadhyay
Electronics 2017, 6(2), 41; https://doi.org/10.3390/electronics6020041 - 20 May 2017
Cited by 17 | Viewed by 9222
Abstract
Measurement of moisture at ppm or ppb level is very difficult and the fabrication of such sensors at low cost is always challenging. High sensitivity is an important parameter for trace level (ppm) humidity sensors. Anelectronic detection circuit for interfacing the humidity sensor [...] Read more.
Measurement of moisture at ppm or ppb level is very difficult and the fabrication of such sensors at low cost is always challenging. High sensitivity is an important parameter for trace level (ppm) humidity sensors. Anelectronic detection circuit for interfacing the humidity sensor with high sensitivity requires a simple hardware circuit with few active devices. The recent trends for increasing the sensitivity include fabricating nanoporous film with a very large surface area. In the present work, the sensitivity of a parallel plate capacitive type sensor with metal oxide sensing film has been significantly improved with an aim to detect moisture from 3 to 100 ppm in the industrial process gases used to fabricate semiconductors and other sensitive electronic devices. The sensitivity has been increased by (i) fabricating a nanoporous film of aluminum oxide using the sol-gel method and (ii) increasing the cross-sectional area of a parallel plate capacitor. A novel double sided capacitive structure has been proposed where two capacitors have been fabricated—one on the top and one on the bottom side of a flat alumina substrate—and then the capacitors are connected in parallel. The structure has twice the sensitivity of a single sensor in the same ppm range but the size of the structure remains unchanged. The important characteristics of the sensors such as the sensitivity (S = Δ C Δ p p m × 100 ), the response time (tr), and the recovery time (tc) are determined and compared with a commercial SHAW, UKdew point meter. The fabricated double sided sensor has comparable sensitivity (S = 100%, tr (s) = 28, tc (s) = 40) with the commercial meter (S = 100.5%, tr (s) = 258) but has a faster response time. The proposed method of sensitivity enhancement is simple, and mass producible. Full article
(This article belongs to the Special Issue Innovative Technologies and Services for Smart Cities)
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2526 KiB  
Article
Energy-Aware Real-Time Task Scheduling in Multiprocessor Systems Using a Hybrid Genetic Algorithm
by Amjad Mahmood, Salman A. Khan, Fawzi Albalooshi and Noor Awwad
Electronics 2017, 6(2), 40; https://doi.org/10.3390/electronics6020040 - 19 May 2017
Cited by 36 | Viewed by 7052
Abstract
Minimizing power consumption to prolong battery life has become an important design issue for portable battery-operated devices such as smartphones and personal digital assistants (PDAs). On a Dynamic Voltage Scaling (DVS) enabled processor, power consumption can be reduced by scaling down the operating [...] Read more.
Minimizing power consumption to prolong battery life has become an important design issue for portable battery-operated devices such as smartphones and personal digital assistants (PDAs). On a Dynamic Voltage Scaling (DVS) enabled processor, power consumption can be reduced by scaling down the operating frequency of the processor whenever the full processing speed is not required. Real-time task scheduling is a complex and challenging problem for DVS-enabled multiprocessor systems. This paper first formulates the real-time task scheduling for DVS-enabled multiprocessor systems as a combinatorial optimization problem. It then proposes a genetic algorithm that is hybridized with the stochastic evolution algorithm to allocate and schedule real-time tasks with precedence constraints. It presents specialized crossover and perturb operations as well as a topology preserving algorithm to generate the initial population. A comprehensive simulation study has been done using synthetic and real benchmark data to evaluate the performance of the proposed Hybrid Genetic Algorithm (HGA) in terms of solution quality and efficiency. The performance of the proposed HGA has been compared with the genetic algorithm, particle swarm optimization, cuckoo search, and ant colony optimization. The simulation results show that HGA outperforms the other algorithms in terms of solution quality. Full article
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6568 KiB  
Article
ROBI’: A Prototype Mobile Manipulator for Agricultural Applications
by Luca Bascetta, Marco Baur and Giambattista Gruosso
Electronics 2017, 6(2), 39; https://doi.org/10.3390/electronics6020039 - 19 May 2017
Cited by 10 | Viewed by 7563
Abstract
The design of ROBI’, a prototype mobile manipulator for agricultural applications devised following low-cost, low-weight, simplicity, flexibility and modularity requirements, is presented in this work. The mechanical design and the selection of the main components of the motion control system, including sensors and [...] Read more.
The design of ROBI’, a prototype mobile manipulator for agricultural applications devised following low-cost, low-weight, simplicity, flexibility and modularity requirements, is presented in this work. The mechanical design and the selection of the main components of the motion control system, including sensors and in-wheel motors, is described. The kinematic and dynamic models of the robot are also derived, with the aim to support the design of a trajectory tracking system and to make a preliminary assessment of the design choices, as well. Finally, two simulations, one specifically related to a realistic trajectory in an agricultural field, show the validity of these choices. Full article
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2236 KiB  
Article
Fully-Integrated Converter for Low-Cost and Low-Size Power Supply in Internet-of-Things Applications
by Fernando Gutierrez
Electronics 2017, 6(2), 38; https://doi.org/10.3390/electronics6020038 - 17 May 2017
Cited by 11 | Viewed by 7011
Abstract
The paper presents a fully-integrated and universal DC/DC converter to minimize cost and size of power supply systems in wireless nodes for Internet-of-Things (IoT) applications. The proposed converter avoids the use of inductors and is made by a cascade of switching capacitor stages, [...] Read more.
The paper presents a fully-integrated and universal DC/DC converter to minimize cost and size of power supply systems in wireless nodes for Internet-of-Things (IoT) applications. The proposed converter avoids the use of inductors and is made by a cascade of switching capacitor stages, implementing both step-down and step-up converting ratios, which regulate input sources from 1 V to 60 V to a voltage of about 4 V. Multiple linear regulators are placed at the end of the cascade to provide multiple and stable output voltages for loads such as memories, sensors, processors, wireless transceivers. The multi-output power converter has been integrated in a Bipolar-CMOS-DMOS (BCD) 180 nm technology. As case study, the generation of 3 output voltages has been considered (3 V, 2.7 V, and 1.65 V with load current requirements of 0.3 A, 0.3 A, and 0.12 A, respectively). Thanks to the adoption of a high switching frequency, up to 5 MHz, the only needed passive components are flying capacitors, whose size is below 10 nF, and buffer capacitors, whose size is below 100 nF. These capacitors can be integrated on top of the chip die, creating a 3D structure. This way, the size of the power management unit for IoT and CPS nodes is limited at 18 mm2. The proposed converter can also be used with changing input power sources, like power harvesting systems and/or very disturbed power supplies. Full article
(This article belongs to the Special Issue Hardware and Architecture)
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1035 KiB  
Article
Full-Diversity QO-STBC Technique for Large-Antenna MIMO Systems
by Kelvin Anoh, Godfrey Okorafor, Bamidele Adebisi, Ali Alabdullah, Steve Jones and Raed Abd-Alhameed
Electronics 2017, 6(2), 37; https://doi.org/10.3390/electronics6020037 - 11 May 2017
Cited by 7 | Viewed by 7187
Abstract
The need to achieve high data rates in modern telecommunication systems, such as 5G standard, motivates the study and development of large antenna and multiple-input multiple-output (MIMO) systems. This study introduces a large antenna-order design of MIMO quasi-orthogonal space-time block code (QO-STBC) system [...] Read more.
The need to achieve high data rates in modern telecommunication systems, such as 5G standard, motivates the study and development of large antenna and multiple-input multiple-output (MIMO) systems. This study introduces a large antenna-order design of MIMO quasi-orthogonal space-time block code (QO-STBC) system that achieves better signal-to-noise ratio (SNR) and bit-error ratio (BER) performances than the conventional QO-STBCs with the potential for massive MIMO (mMIMO) configurations. Although some earlier MIMO standards were built on orthogonal space-time block codes (O-STBCs), which are limited to two transmit antennas and data rates, the need for higher data rates motivates the exploration of higher antenna configurations using different QO-STBC schemes. The standard QO-STBC offers a higher number of antennas than the O-STBC with the full spatial rate. Unfortunately, also, the standard QO-STBCs are not able to achieve full diversity due to self-interference within their detection matrices; this diminishes the BER performance of the QO-STBC scheme. The detection also involves nonlinear processing, which further complicates the system. To solve these problems, we propose a linear processing design technique (which eliminates the system complexity) for constructing interference-free QO-STBCs and that also achieves full diversity using Hadamard modal matrices with the potential for mMIMO design. Since the modal matrices that orthogonalize QO-STBC are not sparse, our proposal also supports O-STBCs with a well-behaved peak-to-average power ratio (PAPR) and better BER. The results of the proposed QO-STBC outperform other full diversity techniques including Givens-rotation and the eigenvalue decomposition (EVD) techniques by 15 dB for both MIMO and multiple-input single-output (MISO) antenna configurations at 10 − 3 BER. The proposed interference-free QO-STBC is also implemented for 16 × N R and 32 × N R MIMO systems, where N R ≤ 2 . We demonstrate 8, 16 and 32 transmit antenna-enabled MIMO systems with the potential for mMIMO design applications with attractive BER and PAPR performance characteristics. Full article
(This article belongs to the Special Issue Smart Antennas and MIMO Communications)
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5770 KiB  
Article
Inspection of Metal and Concrete Specimens Using Imaging System with Laser Displacement Sensor
by Paritosh Giri, Sergey Kharkovsky and Bijan Samali
Electronics 2017, 6(2), 36; https://doi.org/10.3390/electronics6020036 - 7 May 2017
Cited by 16 | Viewed by 5580
Abstract
Flaws such as cracks and impact damages initially occur on the surface of the infrastructure materials and propagate internally causing further degradation. These infrastructure materials have different physical and chemical composition and have different geometric shapes, which can mask the indication of minute [...] Read more.
Flaws such as cracks and impact damages initially occur on the surface of the infrastructure materials and propagate internally causing further degradation. These infrastructure materials have different physical and chemical composition and have different geometric shapes, which can mask the indication of minute surface flaws. There is a need to develop systems that can detect these surface flaws irrespective of their properties and shapes. We propose an imaging system capable of interrogating plain and non-plain structures for the purpose of detection and evaluation of surface flaws such as cracks and impact damages using a laser displacement sensor (LDS). The developed system consists of LDS mounted on the scanner, which is capable of raster scanning over the material under test. The reading of displacement from the sensor head to the laser spot on the surface of the test material is then used to generate two-dimensional (2-D) images in real time, which can be used to detect minute surface flaws. This paper presents the results of inspection of metal and concrete test specimens. 2-D images through the cut of the metal profile are also generated to demonstrate the ability of a system to image interior structure. Full article
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4352 KiB  
Article
A Soft-Switching SEPIC with Multi-Output Sources
by Cheng-Tao Tsai and Jye-Chau Su
Electronics 2017, 6(2), 35; https://doi.org/10.3390/electronics6020035 - 6 May 2017
Cited by 6 | Viewed by 11363
Abstract
In this paper, a soft-switching single-ended-primary-inductance converter (SEPIC) with multi-output sources is proposed. The proposed SEPIC has the following advantages: (1) The conversion efficiency can be increased. To incorporate a soft-switching cell with a flyback-type, the power switches can achieve zero-voltage-switching (ZVS) and [...] Read more.
In this paper, a soft-switching single-ended-primary-inductance converter (SEPIC) with multi-output sources is proposed. The proposed SEPIC has the following advantages: (1) The conversion efficiency can be increased. To incorporate a soft-switching cell with a flyback-type, the power switches can achieve zero-voltage-switching (ZVS) and zero-current-switching (ZCS) features under turn-on transitions, resulting in reducing the switching losses and electromagnetic interference (EMI); (2) The applicability can be maximized. To apply the voltage ratio of the transformers, the proposed SEPIC has multi-output sources with step-up/down voltage functions. Finally, a prototype of the soft-switching SEPIC with multi-output sources is built and implemented. Simulated and experimental results are presented to verify the performance and the feasibility of the proposed soft-switching SEPIC with multi-output sources. Full article
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721 KiB  
Article
Fully Quaternion-Valued Adaptive Beamforming Based on Crossed-Dipole Arrays
by Xiang Lan and Wei Liu
Electronics 2017, 6(2), 34; https://doi.org/10.3390/electronics6020034 - 27 Apr 2017
Cited by 10 | Viewed by 5881
Abstract
Based on crossed-dipole antenna arrays, quaternion-valued data models have been developed for both direction of arrival estimation and beamforming in the past. However, for almost all the models, and especially for adaptive beamforming, the desired signal is still complex-valued as in the quaternion-valued [...] Read more.
Based on crossed-dipole antenna arrays, quaternion-valued data models have been developed for both direction of arrival estimation and beamforming in the past. However, for almost all the models, and especially for adaptive beamforming, the desired signal is still complex-valued as in the quaternion-valued Capon beamformer. Since the complex-valued desired signal only has two components, while there are four components in a quaternion, only two components of the quaternion-valued beamformer output are used and the remaining two are simply discarded, leading to significant redundancy in its implementation. In this work, we consider a quaternion-valued desired signal and develop a fully quaternion-valued Capon beamformer which has a better performance and a much lower complexity. Furthermore, based on this full quaternion model, the robust beamforming problem is also studied in the presence of steering vector errors and a worst-case-based robust beamformer is developed. The performance of the proposed methods is verified by computer simulations. Full article
(This article belongs to the Special Issue Smart Antennas and MIMO Communications)
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885 KiB  
Article
MIMO Channel-State Estimation in the Presence of Partial Data and/or Intermittent Measurements
by Marco Donald Migliore, Daniele Pinchera, Mario Lucido, Fulvio Schettino and Gaetano Panariello
Electronics 2017, 6(2), 33; https://doi.org/10.3390/electronics6020033 - 20 Apr 2017
Cited by 2 | Viewed by 5342
Abstract
We propose a method for estimating the channel matrix in MIMO communication systems from intermittent measurements based on the matrix completion technique. The method requires the minimization of the trace norm of the partially known channel matrix. The availability of fast and efficient [...] Read more.
We propose a method for estimating the channel matrix in MIMO communication systems from intermittent measurements based on the matrix completion technique. The method requires the minimization of the trace norm of the partially known channel matrix. The availability of fast and efficient convex minimization programs allows a numerically efficient solution of the problem. The effectiveness of the technique is numerically investigated considering different scattering environments. Full article
(This article belongs to the Special Issue Smart Antennas and MIMO Communications)
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8331 KiB  
Article
A Probabilistic Approach to RFID-Based Localization for Human-Robot Interaction in Social Robotics
by João S. Sequeira and Duarte Gameiro
Electronics 2017, 6(2), 32; https://doi.org/10.3390/electronics6020032 - 17 Apr 2017
Cited by 6 | Viewed by 5046
Abstract
This paper describes a novel strategy to Radio-Frequency Identification (RFID) tag detection for human– robot interaction (HRI) purposes. The anisotropic detection pattern of the RFID reader antenna is combined with a probabilistic algorithm to obtain a coarse angular position relative to the RFID [...] Read more.
This paper describes a novel strategy to Radio-Frequency Identification (RFID) tag detection for human– robot interaction (HRI) purposes. The anisotropic detection pattern of the RFID reader antenna is combined with a probabilistic algorithm to obtain a coarse angular position relative to the RFID reader that can be used, for example, for behavioral control based on proxemics areas around the robot. The success rate achieved is suitable for HRI purposes. The paper presents experimental results on a detection model for the reader. Full article
(This article belongs to the Special Issue RFID Systems and Applications)
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1925 KiB  
Article
Using Competition to Control Congestion in Autonomous Drone Systems
by Pedro D. Manrique, D. Dylan Johnson and Neil F. Johnson
Electronics 2017, 6(2), 31; https://doi.org/10.3390/electronics6020031 - 12 Apr 2017
Cited by 6 | Viewed by 6641
Abstract
With the number and variety of commercial drones and UAVs (Unmanned Aerial Vehicles) set to escalate, there will be high future demands on popular regions of airspace and communication bandwidths. This raises safety concerns and hence heightens the need for a generic quantitative [...] Read more.
With the number and variety of commercial drones and UAVs (Unmanned Aerial Vehicles) set to escalate, there will be high future demands on popular regions of airspace and communication bandwidths. This raises safety concerns and hence heightens the need for a generic quantitative understanding of the real-time dynamics of multi-drone populations. Here, we explain how a simple system design built around system-level competition, as opposed to cooperation, can be used to control and ultimately reduce the fluctuations that ordinarily arise in such congestion situations, while simultaneously keeping the on-board processing requirements minimal. These benefits naturally arise from the collective competition to choose the less crowded option, using only previous outcomes and built-in algorithms. We provide explicit closed-form formulae that are applicable to any number of airborne drones N, and which show that the necessary on-board processing increases slower than N as N increases. This design therefore offers operational advantages over traditional cooperative schemes that require drone-to-drone communications that scale like N 2 , and also over optimization and control schemes that do not easily scale up to general N. In addition to populations of drones, the same mathematical analysis can be used to describe more complex individual drones that feature N adaptive sensor/actuator units. Full article
(This article belongs to the Special Issue Unmanned Aerial Systems/Vehicles (UAS/V) and Drones)
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4911 KiB  
Article
Static and Moving Target Imaging Using Harmonic Radar
by Kyle A. Gallagher, Ram M. Narayanan, Gregory J. Mazzaro, Anthony F. Martone and Kelly D. Sherbondy
Electronics 2017, 6(2), 30; https://doi.org/10.3390/electronics6020030 - 4 Apr 2017
Cited by 25 | Viewed by 8662
Abstract
Nonlinear radar exploits the difference in frequency between radar waves that illuminate and are reflected from electromagnetically nonlinear targets. Harmonic radar is a special type of nonlinear radar that transmits one or multiple frequencies and listens for frequencies at or near their harmonics. [...] Read more.
Nonlinear radar exploits the difference in frequency between radar waves that illuminate and are reflected from electromagnetically nonlinear targets. Harmonic radar is a special type of nonlinear radar that transmits one or multiple frequencies and listens for frequencies at or near their harmonics. Nonlinear radar differs from traditional linear radar by offering high clutter rejection and is particularly suited to the detection of devices containing metals and semiconductors. Examples include tags for tracking insects, tags worn by humans for avoiding collisions with vehicles, or for monitoring vital signs. Such tags contain a radio-frequency (RF) nonlinearity, often a Schottky diode, connected to a suitable antenna. Targets with inherent nonlinearities, such as metal contacts, semiconductors, transmission lines, antennas, filters, and ferroelectrics, also respond to nonlinear radar. In this paper, the successful exploitation of harmonic radar for moving target imaging and synthetic aperture imaging of targets, while suppressing clutter signals from linear targets, are presented. Our results demonstrate some unique advantages of harmonic radar over its traditional linear counterpart. Full article
(This article belongs to the Special Issue Radio and Radar Signal Processing)
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3884 KiB  
Article
Screening Mississippi River Levees Using Texture-Based and Polarimetric-Based Features from Synthetic Aperture Radar Data
by Lalitha Dabbiru, James V. Aanstoos, John E. Ball and Nicolas H. Younan
Electronics 2017, 6(2), 29; https://doi.org/10.3390/electronics6020029 - 31 Mar 2017
Cited by 3 | Viewed by 7707
Abstract
This article reviews the use of synthetic aperture radar remote sensing data for earthen levee mapping with an emphasis on finding the slump slides on the levees. Earthen levees built on the natural levees parallel to the river channel are designed to protect [...] Read more.
This article reviews the use of synthetic aperture radar remote sensing data for earthen levee mapping with an emphasis on finding the slump slides on the levees. Earthen levees built on the natural levees parallel to the river channel are designed to protect large areas of populated and cultivated land in the Unites States from flooding. One of the signs of potential impending levee failure is the appearance of slump slides. On-site inspection of levees is expensive and time-consuming; therefore, a need to develop efficient techniques based on remote sensing technologies is mandatory to prevent failures under flood loading. Analysis of multi-polarized radar data is one of the viable tools for detecting the problem areas on the levees. In this study, we develop methods to detect anomalies on the levee, such as slump slides and give levee managers new tools to prioritize their tasks. This paper presents results of applying the National Aeronautics and Space Administration (NASA) Jet Propulsion Lab (JPL)’s Uninhabited Aerial Vehicle Synthetic Aperture Radar (UAVSAR) quad-polarized L-band data to detect slump slides on earthen levees. The study area encompasses a portion of levees of the lower Mississippi River in the United States. In this paper, we investigate the performance of polarimetric and texture features for efficient levee classification. Texture features derived from the gray level co-occurrence (GLCM) matrix and discrete wavelet transform were computed and analyzed for efficient levee classification. The pixel-based polarimetric decomposition features, such as entropy, anisotropy, and scattering angle were also computed and applied to the support vector machine classifier to characterize the radar imagery and compared the results with texture-based classification. Our experimental results showed that inclusion of textural features derived from the SAR data using the discrete wavelet transform (DWT) features and GLCM features provided higher overall classification accuracies compared to the pixel-based polarimetric features. Full article
(This article belongs to the Special Issue Radio and Radar Signal Processing)
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2685 KiB  
Article
High Throughput Characterization of Epitaxially Grown Single-Layer MoS2
by Foad Ghasemi, Riccardo Frisenda, Dumitru Dumcenco, Andras Kis, David Perez de Lara and Andres Castellanos-Gomez
Electronics 2017, 6(2), 28; https://doi.org/10.3390/electronics6020028 - 31 Mar 2017
Cited by 18 | Viewed by 7355
Abstract
The growth of single-layer MoS2 with chemical vapor deposition is an established method that can produce large-area and high quality samples. In this article, we investigate the geometrical and optical properties of hundreds of individual single-layer MoS2 crystallites grown on a [...] Read more.
The growth of single-layer MoS2 with chemical vapor deposition is an established method that can produce large-area and high quality samples. In this article, we investigate the geometrical and optical properties of hundreds of individual single-layer MoS2 crystallites grown on a highly-polished sapphire substrate. Most of the crystallites are oriented along the terraces of the sapphire substrate and have an area comprised between 10 µm2 and 60 µm2. Differential reflectance measurements performed on these crystallites show that the area of the MoS2 crystallites has an influence on the position and broadening of the B exciton while the orientation does not influence the A and B excitons of MoS2. These measurements demonstrate that differential reflectance measurements have the potential to be used to characterize the homogeneity of large-area chemical vapor deposition (CVD)-grown samples. Full article
(This article belongs to the Special Issue Two-Dimensional Electronics and Optoelectronics)
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3163 KiB  
Article
Atomic Layer Growth of InSe and Sb2Se3 Layered Semiconductors and Their Heterostructure
by Robert Browning, Neal Kuperman, Bill Moon and Raj Solanki
Electronics 2017, 6(2), 27; https://doi.org/10.3390/electronics6020027 - 30 Mar 2017
Cited by 37 | Viewed by 9015
Abstract
Metal chalcogenides based on the C–M–M–C (C = chalcogen, M = metal) structure possess several attractive properties that can be utilized in both electrical and optical devices. We have shown that specular, large area films of γ-InSe and Sb2Se3 can [...] Read more.
Metal chalcogenides based on the C–M–M–C (C = chalcogen, M = metal) structure possess several attractive properties that can be utilized in both electrical and optical devices. We have shown that specular, large area films of γ-InSe and Sb2Se3 can be grown via atomic layer deposition (ALD) at relatively low temperatures. Optical (absorption, Raman), crystalline (X-ray diffraction), and composition (XPS) properties of these films have been measured and compared to those reported for exfoliated films and have been found to be similar. Heterostructures composed of a layer of γ-InSe (intrinsically n-type) followed by a layer of Sb2Se3 (intrinsically p-type) that display diode characteristics were also grown. Full article
(This article belongs to the Special Issue Two-Dimensional Electronics and Optoelectronics)
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3514 KiB  
Article
Design and optimization of collection efficiency and conversion gain of buried p-well SOI pixel X-ray detector
by Chen Shi, Li Tian, Songlin Feng, Qiliang Li and Hui Wang
Electronics 2017, 6(2), 26; https://doi.org/10.3390/electronics6020026 - 23 Mar 2017
Viewed by 4979
Abstract
Buried P-Well (BPW) technology was used in silicon-on-insulator pixels (SOIPIX) to suppress the back-gate effect, the major challenge in SOIPIX. In this work, we have designed and optimized two novel pixel structures, which are based on different BPW design layouts, to study the [...] Read more.
Buried P-Well (BPW) technology was used in silicon-on-insulator pixels (SOIPIX) to suppress the back-gate effect, the major challenge in SOIPIX. In this work, we have designed and optimized two novel pixel structures, which are based on different BPW design layouts, to study the carrier collection efficiency and conversion gain of the pixel unit used in SOIPIX X-ray detectors. The first structure has an extended BPW region connected with a P+ node. In the second structure, a separated BPW ring region is formed surrounding the P+ node. Two X-ray sources with different photon energies have been applied in the simulation of excess carrier generation. The results indicated that the first structure had higher collection efficiency while the second structure had a slightly better conversion gain. As a result, the total photoelectric voltage of the first structure is about two times that of the second structure, where low doping concentration (<1 × 1016 cm‒3) in the BPW region is preferred. Such a study of design and optimization of BPW technology is very important for applications in SOIPIX detectors Full article
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182 KiB  
Editorial
FPGA and SoC Devices Applied to New Trends in Image/Video and Signal Processing Fields
by Ignacio Bravo-Muñoz, José Luis Lázaro-Galilea and Alfredo Gardel-Vicente
Electronics 2017, 6(2), 25; https://doi.org/10.3390/electronics6020025 - 23 Mar 2017
Cited by 8 | Viewed by 5340
Abstract
Field-programmable gate arrays (FPGAs) and, recently, System on Chip (SoC) devices have been applied in different areas and fields for the past 20 years. [...]
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(This article belongs to the Special Issue FPGA and SoC Devices Applied to New Trends in Image/Video and Signal Processing Fields)
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