Miracle-dz/UniFAR-FTUs huggingface dataset:
Automatic control to compensate misalignments of a wireless power system

This work presents a control procedure for tracking the tuning frequency of a wireless power transfer system. The inductive link tracks the maximum possible power delivered to the load by dynamically tuning the power source frequency, compensating misalignments or movements between the transmitter and receiver coils or any variations of the magnetic coupling factor. Initially, the equivalent circuit of the inductive link is characterized in order to identify the maximum power delivered to the load when both frequency of the power source and magnetic coupling factor k of the coils are varying. Thus, the trajectory of the maximum delivered power to the load is mapped and fitted in the plane of variations of both k and frequency with a polynomial of first degree. Also, the system monitors phase and magnitude of the input current of the inductive link, combining the data with the first degree polynomial and estimates the magnetic coupling coefficient between the transmitter and receiver coils. Finally, the frequency of the power source can be adjusted by a firmware according to the updated k, tracking the maximum power delivered to the load and closing the loop.
A relaxation oscillator based interface circuit for LVDT

This paper presents a simple relaxation oscillator based read-out circuit for Linear Variable Differential Transformer (LVDT). The new scheme does not require precise sine wave oscillator for excitation and the associated phase matching circuits like the traditional methods. The scheme is designed to perform ratiometric computation of the sensing variables and provides an output that is proportional to the measurand, displacement. The primary and the secondary coils are integral parts of a Relaxation Oscillator (RO). The RO injects a current waveform with triangular shape through the primary. This induces a square shape waveform in the secondary coils. The RO utilizes the amplitudes of those waveforms to derive the core position and represents it as a change in duty cycle of the output signal. The PWM output lends itself to easy digitization of the displacement using an up/down counter. Or, if analog output is required, the PWM output can be passed through a low pass filter and the same can be obtained. A prototype of the proposed read-out circuit has been built and tested (a) using standard variable inductors emulating the change in the value of the inductances of an LVDT and (b) a commercially available LVDT. The worst case non-linearity error noted from the tests conducted was less than 0.3 %.
Characteristics of vortex flowmeter in vapor-liquid mist flow

To improve the measurement accuracy of vortex flowmeter in mist flow of wet steam, the meter over-reading of vapor flowrate was investigated. Four general impact factors for dimensionless vortex frequency, namely Strouhal number, were obtained by dimensional analysis. A two-fluid model using Eulerian-Eulerian method was established and validated by the experiments. Then, the unsteady numerical simulations for mist flow around a bluff body were conducted, which indicated that the over-reading is dominantly affected by droplet mass loading and dimensionless droplet diameter. Moreover, the over-reading of vapor flowrate will increase with droplet mass loading, and its growth rate is negatively related with droplet diameter.
Virtual Network Embedding With Adaptive Modulation in Flexi-Grid Networks

Network virtualization has been proposed as a promising method to mitigate the ossification of the Internet by allowing multiple heterogeneous virtual networks (VNs) to coexist on a shared substrate network. One of the major challenges in this method is the VN embedding (VNE) problem of how to map efficiently the virtual nodes and links onto the substrate network considering constraints associated with different substrate networks. This paper aims to solve the VNE problem with geographical constraints in the context of flexi-grid optical networks where modulation modes can be selected optimally. We provide an integer linear programming (ILP) formulation for the problem with the objective function of minimizing the embedding cost of an arriving VN. To achieve scalability, we also propose three polynomial-time heuristic algorithms where virtual links are embedded sequentially by three different sequences, respectively. We find that the sequence considering the bandwidth requirements of the virtual links outperforms the others. Such a sequence leads to a cost-effective VNE solution in terms of spectrum resource usage, which aims to optimize modulation modes and transmission distances of the virtual links that have high bandwidth requirements. Numerical results show that the heuristic algorithm with the sequence considering the bandwidth requirements performs closely to the ILP for a small size network, and we also demonstrate its applicability to larger networks.
A High-Rate BCI Speller Based on Eye-Closed EEG Signal

This paper aims to develop a Brain-computer interface (BCI) speller utilizing eyes-closed and double-blinking electroencephalogram (EEG) signals and based on asynchronous mechanism. The proposed system comprises a signal processing module and a graphical user interface (virtual keyboard-VK) with 26 English characters plus a special symbol. A detected “eyes-closed” (EC) event induces the “select” command, whereas a “double-blinking” (DB) event functions as the “undo” command. A three-class support vector machine classifier involving EEG signal analysis of three groups of events (“eyes-open” - idle state, EC, and DB) is proposed. The results show that the proposed BCI can achieve an overall accuracy of 93.8% for multi-class classification. The proposed speller is then employed in the online experiment of spelling the word “bcispeller” using a 1 s time window. Consequently, it achieves an average accuracy of 92.3% and an average spelling rate of 5 letters/min. Overall, this paper shows improvement with high accuracy and spelling rate demonstrating the feasibility and reliability of implementing a real-world BCI speller.
Multi-criteria decision making for selecting a rational IoT platform

In this paper, the existing methods of multi-criteria decision making for selecting a rational IoT platform when designing IoT systems are considered. The complexity of the selection process is due to the large number of platforms, available on the IoT services market, and the variety of services and features, which they offer. Therefore, the task of selecting a rational IoT platform is very relevant today. This paper presents the application linear convolution and multiplicative convolution methods using two different approaches to forming weight coefficients for criteria: simple ranking and proportional. In addition, the analysis and research of the influence of various methods of multi-criteria decision making on the result of selecting a rational IoT platform have been carried out. The comparative results confirm the appropriateness of the use of the corresponding methods for solving the multi-criteria decision making task, which deals with a selection of the most rational IoT platform in special cases. Properly selected IoT platform allows increasing reliability and safety of the IoT systems for human and industry domains.
Use of Cytochrome P450 Enzyme Isolated From Bacillus Stratosphericus sp. as Recognition Element in Designing Schottky-Based ISFET Biosensor for Hydrocarbon Detection

Cytochrome P450 enzyme isolated from an extremophile Bacillus Stratosphericus sp. was used as the recognition element for an ion-sensitive field effect transistor (ISFET)-based biosensor. The fabricated ISFET is Schottky-based and has silicon dioxide as a sensing layer. The cytochrome P450 component in its present purified form (pH-7.2) in 5% agarose was laid over the SiO2 gate to examine its capability of generating electronic response in the presence of n-hexadecane and reduced nicotinamide adenine dinucleotide phosphate. The partially purified preparation was obtained from the lysozyme treated spheroplast via ion exchange chromatography followed by the gel filtration chromatography. The variation of potential difference between the gate and the source with respect to pH for the bare ISFET and the variation of gate and source potential difference with respect to the concentration of the measurand at constant current have been recorded for analyses. The observed correlation showed good repeatability of the sensor output suggesting a potential functional sensing device for hydrocarbon detection. The sensitivity parameters for the device have been determined to be 50.65 mV/pH and 54.34 mV/molar for the bare ISFET and enzyme field-effect transistor, respectively.
Localization of Near-Field Sources: A Reduced-Dimension MUSIC Algorithm

In this letter, a reduced-dimension multiple signal classification (MUSIC) algorithm for near-field source localization (i.e., elevation angle and range) with uniform linear arrays is proposed. By splitting the directional matrix in terms of angle and range, the reduced-dimension spectrum function can be constructed, where the 2-D spectral search can be avoided and only the spectral search over angle domain is involved. Moreover, in contrast to a rank-reduced (RARE) algorithm with several times of 1-D spectral searches, the proposed algorithm can obtain the angle estimates by only one 1-D search, and then, the paired range estimates can be directly computed, which remarkably decreases the computational complexity. Furthermore, the proposed algorithm can achieve similar estimation accuracy with the 2-D-MUSIC and RARE algorithms. Simulation results are provided to verify the effectiveness and superiority of the reduced-dimension MUSIC algorithm.
Digital-to-time converter with pulse train generation capability

A new field-programmable gate array (FPGA) based digital-to-time converter (DTC) is described that has a unique feature of pulse train generation with very high resolution. As a proof of concept the DTC design was implemented in Spartan-6 FPGA device (45 nm CMOS, Xilinx). The converter generates either absolute delay related to trigger signal or pulse sequence with variable relative delays between pulses. In both cases the resolution of delays is about 20 ps. The time interval between two pulses is generated with jitter below 4.5 ps. An important advantage of the design is also relatively easy implementation.
OLC: Open-Level Control Plane Architecture for Providing Better Scalability in an SDN Network

The Internet has changed the world, regarding how we lead our daily lives and in recent years, with new technologies, such as the Internet of Things and wireless sensor networks escalating this change. However, these technologies bring with them a rapid increase in traffic, thereby putting more load on networks. It is hard to extend the traditional fully distributed architecture and distributed aggregation mechanism to a large scale, because they suffer several drawbacks by using the data plane as a bus to transfer the control discovery messages, which increases the traffic on that plane. Consequently, to solve this issue, a general architecture and discovery mechanism are introduced in this paper with open-level control (OLC) plane architecture, thus providing better scalability in an software defined networking (SDN) network. Regarding OLC, the backbone for different domains and the discovery process for providing a network general view are considered. OLC can scale up the network with high performance even during high traffic. In particular, it has high transparency, with there being no need to change the hardware, software, or protocols on the host side. Finally, the results from a 22 PC testbed verify that OLC offers a reduction in the number of discovery packets in the data plane of 84.2%, 55.2% faster discovery time and scaling up the number of subnets in an SDN network 3.2 times more than with the traditional distributed architecture and mechanism. Moreover, it provides an approximately steady rediscovery time of 4.34 secs even with very high load.
Addiction, Passion, or Confusion? New Theoretical Insights on Exercise Addiction Research From the Case Study of a Female Body Builder

Exercise addiction is widely studied in sport science and psychology, but at this time it is not recognized as an independently diagnosable mental or psychiatric disorder. Indeed, studies on exercise addiction assess a level of risk for disordered exercise behaviour, characterized by lack of control and negative personal consequences. It is argued that commitment and passion are two overlapping features of high exercise involvement which obscure the fine line between healthy and unhealthy exercise. The present case study examined a successful female body builder who initially claimed that she was addicted to exercise. During an interview she also completed three questionnaires and her appraisal of well-being in eight life domains were assessed at present, as well as retrospectively before her intensive involvement with exercise. She was screened under the Non-Substance Related Disorders category of Substance-Related and Addictive Disorders classification of DSM-5 for gambling, by replacing the word "gambling" with "exercise". Although she was susceptible to exercise addiction, attained high scores on obsessive passion, exhibited more than four symptoms on the DSM list, she exhibited no signs of loss of control and she mainly reported positive experiences associated with her exercise behaviour. She has obtained a nearly maximum score on commitment to exercise and high score on harmonious passion. Almost all aspects of her life have changed in positive direction after getting intensely involved in exercise. This case illustrates that the current scholastic path to the study of exercise addiction may be obscured by ambiguous assumptions and unilateral quantitative focus.
Design and simulation of the antenna for RF energy harvesting systems

In this paper, a multi-band fractal antenna is designed and simulated for the using in RF energy harvesting systems. FR4 glass epoxy material is used for antenna design which have the dielectric constant 4.4, with the thickness 1.6 mm and coaxial feed connection is made from the center triangle of the patch. The designed fractal antenna is simulated using Ansys Electronics Desktop 2017, HFSS (High Frequency Electromagnetic Field Simulation). The antenna resonates at 5 different frequencies which are 0.9 GHz, 2.17 GHz, 3.61 GHz, 5.76 GHz and 6.70 GHz respectively. The bandwidths of the antenna at these frequencies are 161.1 MHz, 47.8 MHz, 491.2 MHz, 12.92 MHz and 37.36 MHz respectively. As a result, designed fractal antenna can be used in RF energy harvesting applications with combining rectifier and matching circuits. So antenna can be used to feed electronic components such as wireless sensor networks.
A New Filter-Bank Multicarrier System: The Linearly Processed FBMC System

In this paper, we propose a linearly processed filter-bank multicarrier (LP-FBMC) system which employs faster than Nyquist signaling to remove residual intrinsic interferences. We represent the FBMC transceiver in a matrix form and then apply singular value decomposition-based linear transformation in order to convert the overlapped FBMC data into parallel independent interference-free data. This interference-free characteristic of the proposed LP-FBMC system enables the use of conventional multiple antenna configurations. Performance evaluations show that out-of-band emission performance of the proposed LP-FBMC system is superior to those of conventional quadrature amplitude-based FBMC (FBMC-QAM) and orthogonal frequency division multiplexing systems. Furthermore, the proposed LP-FBMC system outperforms the conventional FBMC-QAM in terms of bit error rate performance when high order modulation is employed under time-varying channel and multiuser uplink environment.
Hybrid recommender system for learning material using content-based filtering and collaborative filtering with good learners' rating

Web-based learning environment has led to the creation of a big number of digital learning materials that offers various topics. Learners spend much time for browsing and filtering information that suits their needs. Limited time can prevent learners from finding useful learning materials. One of the most successful such technique to solve the problem is recommender system which can select items the user is interested in from a large amount of data. Previous research has attempted to use content-based filtering combined with good learners' ratings method (CBF-GL method). This research proposes an improved method for an existing e-learning recommender system with combination of content-based filtering and collaborative filtering with good learners' ratings (CBF-CF-GL method). Adding a collaborative filtering method intended that only ratings from good learners with certain similarity with the active learner are used in rating recommendations. Experiments were conducted for measuring and comparing the Mean Absolute Error (MAE) scores of CBF-CF-GL and CBF-GL methods using the same dataset. The experiment shows that the CBF-GL method has produced a MAE score of 0.542, while the CBF-CF-GL method has given a MAE score of 0.447. It has shown that the inclusion of collaborative filtering considering good learners' ratings has improved the recommendation accuracy.
A botnet detection approach based on the clonal selection algorithm

The paper presents a new technique for the botnets' detection in the corporate area networks. It is based on the usage of the algorithms of the artificial immune systems. Proposed approach is able to distinguish benign network traffic from malicious one using the clonal selection algorithm taking into account the features of the botnet's presence in the network. An approach present the main improvements of the BotGRABBER system. It is able to detect the IRC, HTTP, DNS and P2P botnets.
An Azimuth-Pattern Reconfigurable Antenna Based on Water Grating Reflector

A novel azimuth-pattern reconfigurable antenna based on a water grating reflector is proposed in this paper. A planar circular monopole antenna operating at 5.7-GHz band is designed with three sets of water grating reflectors mounted along the edge of the antenna with an angle-interval of 120°. By choosing the states of loading and unloading water, each set of water grating is switched as a reflector. Radiation patterns of the antenna can be pointed to three specified directions with different angle intervals in the azimuth plane. Key structures of the water grating reflector that affect the radiation performance of the antenna have been investigated in this paper. Simulated and measured results show that the proposed approach is a potential candidate for beam-steering applications.
Ultrasound Transmission Spectral Compensation Using Arbitrary Position and Width Pulse Sets

Ultrasonic testing systems are widely used for the analysis and characterization of materials. In many applications, such as ultrasonic imaging and spectroscopy, wide bandwidth, spectral flatness, and signal-to-noise ratio (SNR) are essential. The transfer function of the ultrasonic transducer is the bandwidth limiting factor. Pulse excitation has limitations in spectral coverage and achievable SNR. Spread spectrum (SS) signals combined with amplitude modulation are used to compensate the spectral losses and widen the bandwidth. Yet, SS signals require arbitrary waveform generation using digital-to-analog converters and linear power amplifiers, resulting in costly, large, and inefficient equipment. To overcome the aforementioned problems, we propose the use of bipolar arbitrary position and width pulses (APWP) sequences derived from nonlinear frequency modulated SS signals. APWP are obtained by an iterative optimization for the spectral flatness and bandwidth of the received signal. Comparisons of the proposed signals with known linear and nonlinear modulation signals are shown in terms of bandwidth and spectral flatness.
How blockchains can improve measuring instruments regulation and control

In the last years, measuring instruments have become quite complex due to the integration of embedded hardware and software components and the increasing aggregation of new features. Consequently, metrological regulation and control require more efforts from notified bodies, becoming slower and more expensive. In this work, we evaluate how blockchains can help to overcome such challenges. We propose a conceptual model for implementing measuring instruments in a distributed blockchain-based architecture, and compare it with traditional measuring instruments and distributed measuring models discussed in previous works. We also develop a security analysis, demonstrating that blockchains-based measuring systems can impact how measuring instruments are used in consumer relations, at the same time that improve security and simplify metrological regulation and control. At the end, we point out the main challenges, suggesting alternatives and potential research lines for future works.
Spectral emissivity calculation based on extreme learning machine

Spectral emissivity has important research significance and application value in the fields of national defense and medical science. The network training is carried out on the test samples through the ELM modeling method in this paper, and the results show that the blackbody is band infrared radiation brightness model in the range of 3 ~ 5μm and 8 ∼ 12μm, used to calculate the different wavelengths of blackbody spectral emissivity. The comparison of the standard blackbody shows that the maximum relative error between the spectral emissivity and the actual spectral emissivity of the ELM network model is less than 1%, and the method is applied to the calculation of the target spectral emissivity of the aircraft skin.
The Secrecy Capacity of Gaussian MIMO Wiretap Channels Under Interference Constraints

Secure signaling over multiple-input multiple-output (MIMO) wiretap channel (WTC) is studied under interference and transmit power constraints. The classical MIMO WTC model is extended to interference-limited scenarios, so that interference to other users does not exceed a given threshold while ensuring simultaneously no information leakage to an eavesdropper. The operational secrecy capacity of the Gaussian MIMO WTC under interference and transmit power constraints is rigorously established in two forms (a non-convex max problem and a convex–concave max–min problem), to which per-antenna power constraints can be added as well. Optimal signaling directions are characterized in the general case, from which (tight) upper bounds to the rank of optimal transmit covariance matrix are derived. A sufficient condition for the optimality of beamforming and a necessary condition for optimal full-rank signaling are given. Closed-form rank-1 and high-rank solutions are obtained in the case of zero interference constraints. Sufficient and necessary conditions for non-zero secrecy capacity are established. The results are extended to multi-user scenarios. A sufficient and necessary condition for the unbounded growth of the secrecy capacity with transmit power is obtained. The interplay between transmit and interference power constraints is studied, and its significant impact on optimal signaling is demonstrated (so that neither constraint can be absorbed into the other one in general, as was sometimes suggested in the literature). Overall, these results provide insights into fundamental information-theoretic limits and optimal signaling strategies for secure communications under interference constraints.