Miracle-dz/UniFAR-FTUs huggingface dataset:
Cell Search Techniques for Underwater Acoustic Cellular Systems

The concept of frequency reuse has been considered for underwater acoustic cellular (UAC) systems owing to the limited available bandwidth of acoustic channels. In a UAC system, the underwater equipment (UE) should detect the identity of the underwater base station (UBS) and synchronize to a serving UBS. In this paper, two different types of cell search techniques are proposed for the downlink of UAC systems based on orthogonal frequency-division multiplexing (OFDM): a Zadoff-Chu sequence-based cell search technique (ZCS-CST) and a linear frequency modulation-based cell search technique (LFM-CST), all at the physical layer. The performances (correlation property, detection probability, and false alarm probability) of the cell search techniques are analyzed and compared with the simulation results in the additive white Gaussian noise (AWGN) and multipath channels. The performances of the cell search techniques are evaluated using the Bellhop channel simulator and field experiment. It is shown that the ZCS-CST is applicable to UAC systems with a small Doppler shift, while the LFM-CST is suitable for UAC systems with a large Doppler shift.
Homing by triangle completion in consumer-oriented virtual reality environments

Homing is a fundamental task which plays a vital role in spatial navigation. Its performance depends on the computation of a homing vector, where human beings can use simultaneously two different cognitive strategies: an online strategy based on the self-motion cues known as path integration (PI), and an offline strategy called piloting based on the spatial image of the path. Studies using virtual reality environments (VE) have shown that human being can perform homing tasks with acceptable performance. However, in these studies, subjects were able to walk naturally across large tracking areas, or researchers provided them with high-end large-immersive displays. Unfortunately, these configurations are far from current consumer-oriented devices, and very little is known about how their limitations can influence these cognitive processes. Using a triangle completion paradigm, we assessed homing tasks in two consumer-oriented displays (an HTC Vive and a GearVR) and two consumer-oriented interaction devices (a Virtuix Omni Treadmill and a Touchpad Control). Our results show that when locomotion is available (treadmill condition), there exist significant effects regarding display and path complexity. In contrast, when locomotion is restricted (touchpad condition), some effects on path complexity were found. Thus, some future research directions are therefore proposed.
Knowledge Enhanced Quality Estimation for Crowdsourcing

Estimating the quality of answers is one of the challenges in crowdsourcing. The previous methods focus on the quality estimation for objective tasks, whereas subjective tasks, as a common type of crowdsourcing tasks, have not been well studied. In this paper, we focus on the quality estimation for subjective crowdsourcing tasks. Considering the high uncertainty of answers for subjective tasks, in this paper, we propose a background knowledge enhanced quality estimation method. More specifically, first we learn the distributed knowledge representation from knowledge graphs and text corpora by utilizing the multi-task learning framework. Then, we construct a pseudo-gold answer set for each task. Next, by comparing the provided answer with the derived pseudo-gold answer set, we calculate two different scores for each answer: 1) symbolic score, which measures the symbolic similarity and 2) embedding score, which indicates the embedding similarity. Finally, we get the final scores for each answer by combining these two scores. The extensive experiments on both universal and domain-specific crowdsourcing tasks show that our method can obtain better performance than other baselines.
28/38 GHz Dual-band Dual-polarized Highly Isolated Antenna for 5G Phased Array Applications

This paper proposed a new dual-band dual-polarized array antenna operating at 28 GHz and 38 GHz for 5G communication applications. Three stacked patches are adopted to achieve the dual-band operation. The lower band from 27.48 to 28.50 GHz is achieved by using the lower large patch, which is couple-fed by the middle patch. While the upper band from 36.94 to 40.43 GHz is achieved by using the middle and upper patches. The two patches resonant at 38 and 40 GHz respectively and the two resonant modes coupled together, which greatly enhances the upper band. To increase the polarization isolation in the lower band, a shorting pin connecting the lower patch and ground is utilized. Taking advantages of the multi-layer technology, the position of the vertical feeding probe between the middle patch and lower patch is slightly shifted to ensure the good impedance matching in both lower band and upper band. For the antenna element, the simulated -12 dB bandwidths are 27.48-28.50 GHz and 36.94-40.43 GHz for the two bands, respectively. The in-band gains are over 6 dBi in the lower band, and over 4 dBi in the upper band. For the 2×2 antenna array, the isolations are better than 20 dB in both bands.
Direct position control of an octarotor unmanned vehicle under wind gust disturbance

In this paper we present the design of a direct position control law of an octarotor under the presence of wind gust. The nominal control law is designed on a Newton-Euler model using a feedback linearisation technique, where a double integral control law is chosen in order to decouple the controlled variables’ dynamics. Then, the wind gust effect is attenuated through an additive correction term, which is based on disturbance observer. An exogenous system is considered in order to estimate the wind gust derivatives, and the overall closed loop boundedness is discussed. Numerical simulations are then reported in order to show the effectiveness of the control scheme, where the observer based technique is compared with the nominal one.
Sensor-Integrated Aperture Coupled Patch Antenna

The aim of this work is to develop a gas sensor integrated into a 2.4 GHz patch antenna. The detection mechanism is to track the resonant behavior of an antenna coupled to an interdigitated capacitor (IDC) on which a sensing material is deposited. When the target gas is adsorbed on the material surface, the effective permittivity changes and a variation in the antenna resonant frequency is observed. In order to avoid compromising either the antenna performance or the sensor performance after deposition of the sensing material, the coupling between the patch radiator and the IDC should be weak. For this reason, an aperture coupled patch (ACP) antenna weakly coupled to an IDC is employed. In this paper, the authors describe the ACP antenna design and its integration with an IDC, its fabrication and testing.
A Text Analytics Architecture for Smart Companies

This paper presents an architecture for Big Data Analytics regarding unstructured content. The architecture is proposed as an industrial solution in a real setting. In particular, the paper focuses on BD (Big Data) for Smart Companies and on Enterprise Content Management for extraction of information from textual BD. It presents the process architecture and discusses some experiments done as part of a larger BD Analytics project.
It's Not what It Looks Like: Measuring Attacks and Defensive Registrations of Homograph Domains

International Domain Names (IDNs)may contain Unicode in addition to ASCII characters. This enables attackers to replace one or even more characters of a well-known domain with visually similar Unicode characters to create new, look-alike domains. These so-called homograph domains are attractive for malicious activities such as phishing or scams because they may appear legitimate to potential victims. In this paper, we propose two measurement setups to detect homograph domains and monitor their activity. Throughout eight months, we detected almost 3,000 homograph domains, targeting technology companies as well as financial institutions. To understand this phenomenon in more detail, we monitored the activity of these domains daily for more than five months and identified multiple instances of scamming and phishing, with some campaigns being active for several months. We also detected previously undiscovered domains used for a widespread scam in which attackers promise free shoes and other goods. In many cases, these domains were not detected by classical detection approaches such as VirusTotal or Google Safe Browsing, or reported only with a delay of several days or weeks compared to our approach. While we did observe defensive registrations of homograph domains by domain owners, we found that they were very limited in scope and did not cover all possible look-alike character replacements. To that end, we conclude our paper with recommendations for domain owners.
Experimental characterization and Monte Carlo simulation of radiation dose in mammography by AGMS-DM+ and OSL nanoDot™ detectors

This work relates to the study of mean glandular dose (MGD) from the measurement and simulation of the entrance surface dose (ESD) using a standard mammography system. ESD has been simulated with the Monte Carlo Simulation code (GEANT4/GATE) for Molybdenum anode/Molybdenum filter (Mo/Mo) in a photon range 26 to 32 keV, and in a current range 40 to 80 mAs. Agreement within 3% between simulations and experimental measurements with two types of commercial detectors, AGMS-DM+ (Solid State kV/Dose Multisensor) and OSL aluminum oxide doped with carbon (Al2O3:C) type nanoDot™ (Landauer Inc.) results have been obtained. Results show that Monte Carlo simulation can be used to optimize the absorbed dose in order to reduce radiological risks in mammography clinical applications.
Metrology for Inductive Charging of Electric Vehicles (MICEV)

The European Union funded project MICEV aims at improving the traceability of electrical and magnetic measurement at charging stations and to better assess the safety of this technology with respect to human exposure. The paper describes some limits of the instrumentation used for electrical measurements in the charging stations, and briefly presents two new calibration facilities for magnetic field meters and electric power meters. Modeling approaches for the efficiency and human exposure assessment are proposed. In the latter case, electromagnetic computational codes have been combined with dosimetric computational codes making use of highly detailed human anatomical phantoms in order to establish human exposure modeling real charging stations. Detailed results are presented for light vehicles where, according to our calculations, the concern towards human exposure is limited. Currently, the project has reached half way point (about 18 months) and will end in August 2020.
Secure Wireless Communication Using Support Vector Machines

We consider a wireless system consisting of $K$ legal users, one access point (AP)and one active eavesdropper. The eavesdropper is assumed to attack the system in the uplink phase. Focusing on intrusion detection, we introduce a framework to create datasets that are then put into support vector machine (SVM)classifiers. The characteristics of the three features (i.e., MEAN, RATIO and SUM)in our datasets are formulated from post-processing signals. Based on the three defined features, artificial training data (ATD)is also formed and used at the AP. By training SVM models, we show the high feasibility of detecting active eavesdroppers in many cases. The performance of our proposed approach is evaluated in terms of accuracy and through numerical examples.
High-gain Bow-tie Antenna Based on Complementary Split-ring Resonators Enhanced Substrate-integrated Waveguide

This paper presents a high gain bow-tie antenna fed by the new type of fully planar substrate-integrated waveguide composed of coupled complementary split-ring resonators (CSRR-SIW). The antenna structure is fully planar, and the CSRRs and the bow-tie element are sculptured on the top and bottom surfaces. The CSRRs, the bow-tie element and the feedline of the bow-tie element produce three different resonant frequencies. They can combine together by adjusting parameters. By inclining the feed-lines of the bow-tie element by 15°, the gain increased by 0.6 dB–0.9 dB over the working band of 7.31 GHz–10.36 GHz compared with the original antenna. In addition, by loading the metamaterial unit cells of non-resonant parallel-line, the gain of the antenna enhances about 0.7 dB-1.1 dB. Finally, the gain between 6.8 dBi–7.5 dBi over the whole working band is obtained.
Novel Reconfigurable Bandpass Filter With Wide Tunable Bandwidth

This paper presents a reconfigurable bandpass filter by cascading the reconfigurable high-pass and low-pass units. The high-pass and low-pass units can be designed independently to realize the lower and higher cut-off frequency agility. Then the high-pass and the low-pass units are cascaded to compose the proposed reconfigurable bandpass filter with tunability of center frequency, bandwidth simultaneously. The lumped equivalent circuits of high-pass and low-pass filters are analyzed and demonstrated by simulation. The simulated results demonstrate a good frequency selectivity, wide tuning range and ultra-wide fractional bandwidth tunability of the bandpass filter.
Fatigue Evaluation Using Multi-Scale Entropy of EEG in SSVEP-Based BCI

Fatigue is a major challenge when moving steady-state visual evoked potential (SSVEP)-based brain-computer interfaces (BCIs) from the laboratory into real-life applications, as it leads to user’s discomfort and system performance degradation. To study and eventually reduce the fatigue, the first step is to know the fatigue level for which a reliable and objective method to the assessment would be very important and helpful. This paper considers the synchronization of brain activities at multiple time scales as such a measure. Specifically, we propose an objective fatigue index based on the multi-scale entropy (MSE) of subjects’ electroencephalogram (EEG) and validate it through an experimental study on 12 subjects. Main results show that the proposed fatigue index is significantly correlated with the subjective fatigue index and it can be used to distinguish the “alert” and “fatigue” states with 97% accuracy, which is significantly better than the existing fatigue indices based on different EEG spectrum, such as <inline-formula> <tex-math notation="LaTeX">$\theta $ </tex-math></inline-formula>, <inline-formula> <tex-math notation="LaTeX">$\alpha $ </tex-math></inline-formula>, and <inline-formula> <tex-math notation="LaTeX">$\beta $ </tex-math></inline-formula>. The proposed fatigue index would provide an assessment tool for the smart wearable BCI in real-life applications and an ergonomic evaluation method for other human–machine cooperation.
A Reinforced Blind Color Image Watermarking Scheme Based on Schur Decomposition

In this paper, the deficiency of Schur decomposition (SD) for image watermarking has been comprehensively investigated. A remedial scheme is developed not only to fix the existing problems but also to reinforce the performance in robustness and imperceptibility. This scheme starts with partitioning the host image into non-overlapping blocks of $4\times 4$ pixels and then applying SD to each block individually. Level shifting serves as a controlling gauge for embedding strength. The use of intentional perturbation prevents nil orthonormal vectors derived from zero eigenvalues. The dominant vector is identified by analyzing the entire Schur matrix instead of just diagonal elements. To achieve effective watermark embedding and extraction, the orthonormality of the acquired unitary matrix ought to be preserved while the resulting distortion can be compensated via the systematic modification of the Schur matrix. Finally, a recursive regulation guarantees the retrieval of watermark bits. Experiment results indicate that the proposed scheme is free of errors in the absence of attacks and can withstand a variety of image processing attacks as well. Moreover, the inclusion of distortion compensation contributes an improvement of 2.47 dB in terms of peak signal-to-noise ratio. In comparison with previous SD-based schemes, the proposed one exhibits superior robustness and imperceptibility while operating at the same payload capacity.
Virtual Agent Positioning Driven by Scene Semantics in Mixed Reality

When a user interacts with a virtual agent via a mixed reality device, such as a Hololens or a Magic Leap headset, it is important to consider the semantics of the real-world scene in positioning the virtual agent, so that it interacts with the user and the objects in the real world naturally. Mixed reality aims to blend the virtual world with the real world seamlessly. In line with this goal, in this paper, we propose a novel approach to use scene semantics to guide the positioning of a virtual agent. Such considerations can avoid unnatural interaction experiences, e.g., interacting with a virtual human floating in the air. To obtain the semantics of a scene, we first reconstruct the 3D model of the scene by using the RGB-D cameras mounted on the mixed reality device (e.g., a Hololens). Then, we employ the Mask R-CNN object detector to detect objects relevant to the interactions within the scene context. To evaluate the positions and orientations for placing a virtual agent in the scene, we define a cost function based on the scene semantics, which comprises a visibility term and a spatial term. We then apply a Markov chain Monte Carlo optimization technique to search for an optimized solution for placing the virtual agent. We carried out user study experiments to evaluate the results generated by our approach. The results show that our approach achieved a higher user evaluation score than that of the alternative approaches.
An Analytical Approach to Direct Torque and Flux Control of Interior Permanent Magnet Synchronous Machine for Deep Field Weakening Without Using Pre-calculated Lookup Tables

This paper presents an analytic approach to direct torque and flux controller (DTFC) for Interior permanent magnet synchronous machine (IPMSM) which includes deep flux weakening. Unlike the conventional lookup tables (LUTs) based DTFC, this paper proposes a direct mathematical calculation approach for the stator flux reference as well as the torque limit in field weakening (FW) and maximum-torque-per-voltage (MTPV) regions. The proposed method will thus allow flexibility of using online estimated machine parameters directly for an optimized IPMSM drive. This study also explores the voltage and current limit trajectories on a torque-flux linkage plane to operate the machine in deep field weakening. It incorporates maximum-torque-per-ampere (MTPA), FW, and MTPV trajectories control under voltage and current constraints. Experimental results are shown to verify the effectiveness of the proposed algorithm.
Smart Crop Cultivation Monitoring System by Using IoT

Agricultural is an important field of economic development in Lao. Farming needs to be adapted in order to be able to satisfy consumers, so using IoT (Internet of Things) to help in this field is one of the preferred alternatives in the present. In this research, the system monitoring of soil moisture, temperature and water control has been proposed by using NodeMCU ESP8266, sensors and Cloud Computing. To study the effects of growth rate, producing rate, water saving rate of crop planting the three methods such as traditional farm, the greenhouse by using a timer to control soil moisture and the greenhouse by using sensors to automatically control soil moisture was set up and experimented on the melon farm. After that, we have kept track and record all statistics of each part of the plants such as height, its flower, and fruit every week for ten weeks, then analyse it on average in percentage (%) by using Excel to gather information. The results of all experiments compared with method using sensor to automatically control soil moisture, the result as following: grown rate is better than traditional farm 41.2% and better than a timer to control soil moisture is 23.1%; productivity is getting more than traditional farm 70% and get more than a timer to control soil moisture is 12.1%; water saving better than traditional farm 20.9% and better than a timer to control soil moisture is 5.5%.
High Gain 0.25 μm GaN HEMT Based MMIC LNA for GNSS Applications

In this paper, two-stages low noise amplifier (LNA) based on common-source with feedback topology was designed using ALGAN/GAN 0.25um high electron mobility transistor (HEMT) technology on silicon carbide (SiC) substrate. The LNA is designed to be employed for Global Navigation Satellite System (GNSS) Applications. The feedback circuit topology is used in the design to achieve a noise figure of 1 - 1.2 dB with a small signal gain of 33-34 dB. Post-Layout simulation results demonstrate that the input return loss is −11 to −14 dB and the output return loss is −16 to −18 dB across the entire frequency range of 1.5 GHz to 1.7 GHz. The LNA has an output P1 dB and OIP3 of 18 dBm and 28 dBm, respectively which illustrated high linear performance. The power consumption is 0.7 W using a voltage supply of 5.5 V. The total chip size is 2.6 mm x 2.2 mm including the pads.
On-off Dual Channel Coding as a Team Decision Problem

We consider the “single-letter” (“one-shot” or “zero-delay”) source-channel coding of a sensor's measurements in the presence of two channels as a constrained team decision theory problem. Under a global power constraint and quadratic distortion measure, the action space of coding strategies is restricted to on-off (transmission or silence) decisions. The latter are communicated to the decoder through a binary side channel, whereas in case of transmission the uncoded analog measurement is sent over the main communication channel between the transmitter and the receiver. By further restrictions on the behavior of the encoder, suboptimal team control strategies are derived in closed form, along with their parameters that stem from a numerical optimization problem. The distortion of the resulting strategy is compared with other schemes under non-Gaussian source and noise.
Individually Controllable Tri-band Negative Group Delay Circuit using Defected Microstrip Structure

In this report, an approach for designing multiband negative group delay circuit (NGDC) by using composite L-shaped defected microstrip structure (DMS) is proposed. With conductor strip defections, multiple resonances can be implemented, and the center frequencies of the NGDC can be controlled individually, while the desired group delay (GD) time can be easily adjusted by the external resistors independently. A tri-band NGDC with the GD time of −6.5/5.4/-3.0ns at 2.8/4.3/5.8GHz, respectively, is designed and fabricated. The experimental results demonstrate the design. The proposed NGDC has a miniature circuit size of 0. 387λg× 0. 032λg, and an attenuation of less than 24dB.
Fault detection of a VTOL UAV using Acceleration Measurements

This paper proposes an actuator fault detection algorithm for vertical take-off and landing (VTOL) unmanned aerial vehicle (UAV), based on acceleration signals provided by a high-rate inertial measurement unit. The proposed algorithm is based on time and frequency-domain analysis of acceleration signals and features selection techniques in order to identify the most relevant frequencies of the spectrum and time-domain features involved in the occurrence of the fault. The testing of the algorithm is focused on the damage of a propeller blade and the effects of such damage during vertical take-off and landing, where all the lift is generated by the propellers. The algorithm is tested on real data acquired on the Songbird VTOL UAV [1]. The experimental results prove the possibility of using acceleration signals for diagnostic purposes on VTOL UAVs.