Open AccessFeature PaperArticle
Space Debris Detection in Low Earth Orbit with the Sardinia Radio Telescope
Electronics 2017, 6(3), 59; doi:10.3390/electronics6030059 -
Abstract
Space debris are orbiting objects that represent a major threat for space operations. The most used countermeasure to face this threat is, by far, collision avoidance, namely the set of maneuvers that allow to avoid a collision with the space debris. Since collision
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Space debris are orbiting objects that represent a major threat for space operations. The most used countermeasure to face this threat is, by far, collision avoidance, namely the set of maneuvers that allow to avoid a collision with the space debris. Since collision avoidance is tightly related to the knowledge of the debris state (position and speed), the observation of the orbital debris is the key of the problem. In this work a bistatic radar configuration named BIRALET (BIstatic RAdar for LEO Tracking) is used to detect a set of space debris at 410 MHz, using the Sardinia Radio Telescope as the receiver antenna. The signal-to-noise ratio, the Doppler shift and the frequency spectrum for each debris are reported. Full article
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Open AccessArticle
A Formally Reliable Cognitive Middleware for the Security of Industrial Control Systems
Electronics 2017, 6(3), 58; doi:10.3390/electronics6030058 -
Abstract
In this paper, we present our results on the formal reliability analysis of the behavioral correctness of our cognitive middleware ARMET. The formally assured behavioral correctness of a software system is a fundamental prerequisite for the system’s security. Therefore, the goal of this
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In this paper, we present our results on the formal reliability analysis of the behavioral correctness of our cognitive middleware ARMET. The formally assured behavioral correctness of a software system is a fundamental prerequisite for the system’s security. Therefore, the goal of this study is to, first, formalize the behavioral semantics of the middleware and, second, to prove its behavioral correctness. In this study, we focus only on the core and critical component of the middleware: the execution monitor. The execution monitor identifies inconsistencies between runtime observations of an industrial control system (ICS) application and predictions of the specification of the application. As a starting point, we have defined the formal (denotational) semantics of the observations (produced by the application at run-time), and predictions (produced by the executable specification of the application). Then, based on the formal semantices, we have formalized the behavior of the execution monitor. Finally, based on the semantics, we have proved soundness (absence of false alarms) and completeness (detection of arbitrary attacks) to assure the behavioral correctness of the monitor. Full article
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Open AccessFeature PaperReview
Carbon Nanotube-Based Nanomechanical Sensor: Theoretical Analysis of Mechanical and Vibrational Properties
Electronics 2017, 6(3), 56; doi:10.3390/electronics6030056 -
Abstract
This paper reviews the recent research of carbon nanotubes (CNTs) used as nanomechanical sensing elements based mainly on theoretical models. CNTs have demonstrated considerable potential as nanomechanical mass sensor and atomic force microscope (AFM) tips. The mechanical and vibrational characteristics of CNTs are
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This paper reviews the recent research of carbon nanotubes (CNTs) used as nanomechanical sensing elements based mainly on theoretical models. CNTs have demonstrated considerable potential as nanomechanical mass sensor and atomic force microscope (AFM) tips. The mechanical and vibrational characteristics of CNTs are introduced to the readers. The effects of main parameters of CNTs, such as dimensions, layer number, and boundary conditions on the performance characteristics are investigated and discussed. It is hoped that this review provides knowledge on the application of CNTs as nanomechanical sensors and computational methods for predicting their properties. Their theoretical studies based on the mechanical properties such as buckling strength and vibration frequency would give a useful reference for designing CNTs as nanomechanical mass sensor and AFM probes. Full article
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Open AccessFeature PaperArticle
Antenna Arrays for Line-of-Sight Massive MIMO: Half Wavelength Is Not Enough
Electronics 2017, 6(3), 57; doi:10.3390/electronics6030057 -
Abstract
The aim of this paper is to analyze the array synthesis for 5 G massive MIMO systems in the line-of-sight working condition. The main result of the numerical investigation performed is that non-uniform arrays are the natural choice in this kind of application.
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The aim of this paper is to analyze the array synthesis for 5 G massive MIMO systems in the line-of-sight working condition. The main result of the numerical investigation performed is that non-uniform arrays are the natural choice in this kind of application. In particular, by using non-equispaced arrays, we show that it is possible to achieve a better average condition number of the channel matrix and a significantly higher spectral efficiency. Furthermore, we verify that increasing the array size is beneficial also for circular arrays, and we provide some useful rules-of-thumb for antenna array design for massive MIMO applications. These results are in contrast to the widely-accepted idea in the 5 G massive MIMO literature, in which the half-wavelength linear uniform array is universally adopted. Full article
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Open AccessFeature PaperArticle
A New Type of Explosive Chemical Detector Based on an Organic Photovoltaic Cell
Electronics 2017, 6(3), 55; doi:10.3390/electronics6030055 -
Abstract
A new type of chemical sensor to detect explosive related compounds has been designed and fabricated with an organic photovoltaic cell as the active element. The detection of chemical molecules is performed by optically exciting the cell while its photovoltaic open-circuit voltage is
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A new type of chemical sensor to detect explosive related compounds has been designed and fabricated with an organic photovoltaic cell as the active element. The detection of chemical molecules is performed by optically exciting the cell while its photovoltaic open-circuit voltage is continuously sampled. Upon exposure to compounds like nitroaromatics, the sensors exhibit a significant increase in open-circuit voltage. This indicates an efficient internal energy transfer between the explosive chemicals and the organic thin film surface. It is quite unique that the organic chemical sensors directly use the open-circuit voltage as a detection indicator, while the vast majority of conventional chemical sensors are based on the change in resistance. Since the open-circuit voltage can be measured without current and can also be directly sampled or amplified in the circuits, this new type of chemical sensor is very attractive for low-power application and sensor networks for the future Internet of Things. Full article
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Open AccessArticle
A Data Compression Hardware Accelerator Enabling Long-Term Biosignal Monitoring Based on Ultra-Low Power IoT Platforms
Electronics 2017, 6(3), 54; doi:10.3390/electronics6030054 -
Abstract
For highly demanding scenarios such as continuous bio-signal monitoring, transmitting excessive volumes of data wirelessly comprises one of the most critical challenges. This is due to the resource limitations posed by typical hardware and communication technologies. Driven by such shortcomings, this paper aims
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For highly demanding scenarios such as continuous bio-signal monitoring, transmitting excessive volumes of data wirelessly comprises one of the most critical challenges. This is due to the resource limitations posed by typical hardware and communication technologies. Driven by such shortcomings, this paper aims at addressing the respective deficiencies. The main axes of this work include (a) data compression, and (b) the presentation of a complete, efficient and practical hardware accelerator design able to be integrated in any Internet of Things (IoT) platform for addressing critical challenges of data compression. On one hand, the developed algorithm is presented and evaluated on software, exhibiting significant benefits compared to respective competition. On the other hand, the algorithm is fully implemented on hardware providing a further proof of concept regarding the implementation feasibility with respect to state-of-the art hardware design approaches. Finally, system-level performance benefits, regarding data transmission delay and energy saving, are highlighted, taking into consideration the characteristics of prominent IoT platforms. Concluding, this paper presents a holistic approach based on data compression that is able to drastically enhance an IoT platform’s performance and tackle efficiently a notorious challenge of highly demanding IoT applications such as real-time bio-signal monitoring. Full article
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Open AccessEditorial
Two-Dimensional Electronics and Optoelectronics: Present and Future
Electronics 2017, 6(3), 53; doi:10.3390/electronics6030053 -
Open AccessArticle
Exploiting Hardware Vulnerabilities to Attack Embedded System Devices: a Survey of Potent Microarchitectural Attacks
Electronics 2017, 6(3), 52; doi:10.3390/electronics6030052 -
Abstract
Cyber-Physical system devices nowadays constitute a mixture of Information Technology (IT) and Operational Technology (OT) systems that are meant to operate harmonically under a security critical framework. As security IT countermeasures are gradually been installed in many embedded system nodes, thus securing them
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Cyber-Physical system devices nowadays constitute a mixture of Information Technology (IT) and Operational Technology (OT) systems that are meant to operate harmonically under a security critical framework. As security IT countermeasures are gradually been installed in many embedded system nodes, thus securing them from many well-know cyber attacks there is a lurking danger that is still overlooked. Apart from the software vulnerabilities that typical malicious programs use, there are some very interesting hardware vulnerabilities that can be exploited in order to mount devastating software or hardware attacks (typically undetected by software countermeasures) capable of fully compromising any embedded system device. Real-time microarchitecture attacks such as the cache side-channel attacks are such case but also the newly discovered Rowhammer fault injection attack that can be mounted even remotely to gain full access to a device DRAM (Dynamic Random Access Memory). Under the light of the above dangers that are focused on the device hardware structure, in this paper, an overview of this attack field is provided including attacks, threat directives and countermeasures. The goal of this paper is not to exhaustively overview attacks and countermeasures but rather to survey the various, possible, existing attack directions and highlight the security risks that they can pose to security critical embedded systems as well as indicate their strength on compromising the Quality of Service (QoS) such systems are designed to provide. Full article
Open AccessEditorial
The Raspberry Pi: A Technology Disrupter, and the Enabler of Dreams
Electronics 2017, 6(3), 51; doi:10.3390/electronics6030051 -
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Open AccessArticle
Risk Analysis of the Future Implementation of a Safety Management System for Multiple RPAS Based on First Demonstration Flights
Electronics 2017, 6(3), 50; doi:10.3390/electronics6030050 -
Abstract
The modern aeronautical scenario has welcomed the massive diffusion of new key elements, including the Remote Piloted Aircraft Systems (RPAS), initially used for military purposes only. The current decade has seen RPAS ready to become a new airspace user in a large variety
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The modern aeronautical scenario has welcomed the massive diffusion of new key elements, including the Remote Piloted Aircraft Systems (RPAS), initially used for military purposes only. The current decade has seen RPAS ready to become a new airspace user in a large variety of civilian applications. Although RPAS can currently only be flown into segregated airspaces, due to national and international Flight Aviation Authorities′ (FAAs) constraints, they represent a remarkable potential growth in terms of development and economic investments for aviation. Full RPAS development will only happen when flight into non-segregated airspaces is authorized, as for manned civil and military aircraft. The preliminary requirement for disclosing the airspace to RPAS is the implementation of an ad hoc Safety Management System (SMS), as prescribed by ICAO, for every aeronautical operator. This issue arises in the context of the ongoing restructuring of airspaces management, according to SESAR-JU in Europe and NextGen in the USA (SESAR-JU has defined how RPAS research should be conducted in SESAR 2020, all in accordance with the 2015 European ATM Master Plan). This paper provides the basis to implement a risk model and general procedures/methodologies to investigate RPAS safety, according to the operational scenarios defined by EASA (European Aviation Safety Agency). The study is based on results achieved by multiple-RPAS experimental flights, performed within the RAID (RPAS-ATM Integration Demonstration) project. Full article
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Open AccessArticle
Multidimensional-DSP Beamformers Using the ROACH-2 FPGA Platform
Electronics 2017, 6(3), 49; doi:10.3390/electronics6030049 -
Abstract
Antenna array-based multi-dimensional infinite-impulse response (IIR) digital beamformers are employed in a multitude of radio frequency (RF) applications ranging from electronically-scanned radar, radio telescopes, long-range detection and target tracking. A method to design 3D IIR beam filters using 2D IIR beam filters is
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Antenna array-based multi-dimensional infinite-impulse response (IIR) digital beamformers are employed in a multitude of radio frequency (RF) applications ranging from electronically-scanned radar, radio telescopes, long-range detection and target tracking. A method to design 3D IIR beam filters using 2D IIR beam filters is described. A cascaded 2D IIR beam filter architecture is proposed based on systolic array architecture as an alternative for an existing radar application. Differential-form transfer function and polyphase structures are employed in the design to gain an increase in the speed of operation to gigahertz range. The feasibility of practical implementation of a 4-phase polyphase 2D IIR beam filter is explored. A digital hardware prototype is designed, implemented and tested using a ROACH-2 Field Programmable Gate Array (FPGA) platform fitted with a Xilinx Virtex-6 SX475T FPGA chip and multi-input analog-to-digital converters (ADC) boards set to a maximum sampling rate of 960 MHz. The article describes a method to build a 3D IIR beamformer using polyphase structures. A comparison of technical specifications of an existing radar application based on phased-array and the proposed 3D IIR beamformer is also explained to illustrate the proposed method to be a better alternative for such applications. Full article
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Open AccessArticle
Design And Implementation of Low Area/Power Elliptic Curve Digital Signature Hardware Core
Electronics 2017, 6(2), 46; doi:10.3390/electronics6020046 -
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
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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
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Open AccessArticle
Security Interrogation and Defense for SAR Analog to Digital Converter
Electronics 2017, 6(2), 48; doi:10.3390/electronics6020048 -
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,
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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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Open AccessArticle
A Galvanic Intrabody Method for Assessing Fluid Flow in Unilateral Lymphoedema
Electronics 2017, 6(2), 47; doi:10.3390/electronics6020047 -
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
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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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Open AccessArticle
Remote System Update for System on Programmable Chip Based on Controller Area Network
Electronics 2017, 6(2), 45; doi:10.3390/electronics6020045 -
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
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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
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Open AccessFeature PaperReview
Recent Advances in Electronic and Optoelectronic Devices Based on Two-Dimensional Transition Metal Dichalcogenides
Electronics 2017, 6(2), 43; doi:10.3390/electronics6020043 -
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
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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
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Open AccessArticle
On the Generality of Codebook Approach for Sensor-Based Human Activity Recognition
Electronics 2017, 6(2), 44; doi:10.3390/electronics6020044 -
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.
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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
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Open AccessArticle
Improved Cell Search for mmWave Cellular Networks Using Deterministic Scanning Algorithm with Directional Array Antenna
Electronics 2017, 6(2), 42; doi:10.3390/electronics6020042 -
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
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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
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Open AccessArticle
Sensitivity Enhancement of a PPM Level Capacitive Moisture Sensor
Electronics 2017, 6(2), 41; doi:10.3390/electronics6020041 -
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
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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 = ΔCΔppm×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
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Open AccessArticle
Energy-Aware Real-Time Task Scheduling in Multiprocessor Systems Using a Hybrid Genetic Algorithm
Electronics 2017, 6(2), 40; doi:10.3390/electronics6020040 -
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
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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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