Sensors, Vol. 21, Pages 5094: Aircraft Detection Using Phase-Sensitive Optical-Fiber OTDR
We present a detection system using Φ-OTDR technology and analyze the character of the acoustic signal of aircraft. Instead of runway monitoring in the airport or noise detection in the air, this study focuses on the detection of seismic vibration signal excited by the sound of aircraft. The Chebyshev filter is adopted to eliminate the impact of background noise and random noise from the original vibration signal; the short-time Fourier transform is used for time-frequency analysis. The experimental results showed that the seismic vibration signal excited by the aircraft sound is mainly low-frequency, which is under 5 ...
Source: Sensors - July 28, 2021 Category: Biotechnology Authors: Yunpeng Cai Jihui Ma Wenfa Yan Wenyi Zhang Yuhang An Tags: Communication Source Type: research

Sensors, Vol. 21, Pages 5066: Analysis of Predistortion Techniques on Fresnel Zone Plates in Ultrasound Applications
Belmar Pilar Candelas In this work, we analyze the effect of predistortion techniques on the focusing profile of Fresnel Zone Plates (FZPs) in ultrasound applications. This novel predistortion method is based on either increasing or decreasing the width of some of the FZP Fresnel rings by a certain amount. We investigate how the magnitude of the predistortion, as well as the number and location of the predistorted rings, influences the lens focusing profile. This focusing profile can be affected in different ways depending on the area of the lens where the predistortion is applied. It is shown that when the inner are...
Source: Sensors - July 27, 2021 Category: Biotechnology Authors: Jos é Miguel Fuster Sergio P érez-López Francisco Belmar Pilar Candelas Tags: Communication Source Type: research

Sensors, Vol. 21, Pages 5067: Noise Sources and Requirements for Confocal Raman Spectrometers in Biosensor Applications
alter Hauswald Raman spectroscopy probes the biochemical composition of samples in a non-destructive, non-invasive and label-free fashion yielding specific information on a molecular level. Nevertheless, the Raman effect is very weak. The detection of all inelastically scattered photons with highest efficiency is therefore crucial as well as the identification of all noise sources present in the system. Here we provide a study for performance comparison and assessment of different spectrometers for confocal Raman spectroscopy in biosensor applications. A low-cost, home-built Raman spectrometer with a complementary meta...
Source: Sensors - July 27, 2021 Category: Biotechnology Authors: Izabella J. Jahn Alexej Grjasnow Henry John Karina Weber J ürgen Popp Walter Hauswald Tags: Article Source Type: research

Sensors, Vol. 21, Pages 5069: Low-Cost and Highly Sensitive Pressure Sensor with Mold-Printed Multi-Walled Carbon Nanotubes Dispersed in Polydimethylsiloxane
ang Flexible pressure sensors with piezoresistive polymer composites can be integrated into elastomers to measure pressure changes in sealings, preemptively indicating a replacement is needed before any damage or leakage occurs. Integrating small percentages of high aspect ratio multi-walled carbon nanotubes (MWCNTs) into polymers does not significantly change its mechanical properties but highly affects its electrical properties. This research shows a pressure sensor based on homogeneous dispersed MWCNTs in polydimethylsiloxane with a high sensitivity region (0.13% kPa−1, 0–200 kPa) and sensitive up to 500...
Source: Sensors - July 27, 2021 Category: Biotechnology Authors: Tim Mike de Rijk Walter Lang Tags: Article Source Type: research

Sensors, Vol. 21, Pages 5068: A Study of Deep Learning-Based Face Recognition Models for Sibling Identification
In this study, we investigate the use of state-of-the-art deep learning face recognition models to evaluate their capacity for discrimination between sibling faces using various similarity indices. The specific models examined for this purpose are FaceNet, VGGFace, VGG16, and VGG19. For each pair of images provided, the embeddings have been calculated using the chosen deep learning model. Five standard similarity measures, namely, cosine similarity, Euclidean distance, structured similarity, Manhattan distance, and Minkowski distance, are used to classify images looking for their identity on the threshold defined for each ...
Source: Sensors - July 27, 2021 Category: Biotechnology Authors: Rita Goel Irfan Mehmood Hassan Ugail Tags: Article Source Type: research

Sensors, Vol. 21, Pages 5070: Exploiting Capture Diversity for Performance Enhancement of ALOHA-Based Multi-Static Backscattering Systems in the 6G Perspective
tucci In this paper, we consider the emerging context of ALOHA-based multi-static backscattering communication systems. By assuming an architecture consisting of a set of passive backscattering nodes, an illuminator, and a set of spatially dislocated receivers, we firstly propose a cross-layer framework for performance analysis. The model jointly accounts for the shared wireless channel, including fading and capture effect, and channel contention strategy, which is regulated by a Framed Slotted ALOHA protocol. Furthermore, based on the inherent macroscopic diversity offered by the multi-static settings, we introduce th...
Source: Sensors - July 27, 2021 Category: Biotechnology Authors: Roberto Valentini Piergiuseppe Di Marco Fortunato Santucci Tags: Article Source Type: research

Sensors, Vol. 21, Pages 5071: Deconstructing Commercial Wearable Technology: Contributions toward Accurate and Free-Living Monitoring of Sleep
lster Despite prolific demands and sales, commercial sleep assessment is primarily limited by the inability to “measure” sleep itself; rather, secondary physiological signals are captured, combined, and subsequently classified as sleep or a specific sleep state. Using markedly different approaches compared with gold-standard polysomnography, wearable companies purporting to measure sleep have rapidly developed during recent decades. These devices are advertised to monitor sleep via sensors such as accelerometers, electrocardiography, photoplethysmography, and temperature, alone or in combination, to estimat...
Source: Sensors - July 27, 2021 Category: Biotechnology Authors: Lauren E. Rentz Hana K. Ulman Scott M. Galster Tags: Review Source Type: research

Sensors, Vol. 21, Pages 5072: Preliminary Investigation on Phytoplankton Dynamics and Primary Production Models in an Oligotrophic Lake from Remote Sensing Measurements
This study represents a preliminary outcome supporting the PP monitoring in inland waters by means of remote sensing-based indices and fluorescence metrics. (Source: Sensors)
Source: Sensors - July 27, 2021 Category: Biotechnology Authors: Ilaria Cesana Mariano Bresciani Sergio Cogliati Claudia Giardino Remika Gupana Dario Manca Stefano Santabarbara Monica Pinardi Martina Austoni Andrea Lami Roberto Colombo Tags: Article Source Type: research

Sensors, Vol. 21, Pages 5075: Ex-Vivo Measurement of the pH in Aqueous Humor Samples by a Tapered Fiber-Optic Sensor
an Kašík Šárka Pitrová Ali A. Jasim A practical demonstration of pH measurement in real biological samples with an in-house developed fiber-optic pH sensor system is presented. The sensor uses 8-hydroxypyrene-1,3,6-trisulfonate (HPTS) fluorescent dye as the opto-chemical transducer. The dye is immobilized in a hybrid sol-gel matrix at the tip of a tapered optical fiber. We used 405 nm and 450 nm laser diodes for the dye excitation and a photomultiplier tube as a detector. The sensor was used for the measurement of pH in human aqueous humor samples during cataract surgery. Two grou...
Source: Sensors - July 27, 2021 Category: Biotechnology Authors: Ond řej Podrazký Jan Mr ázek Jana Probo štová So ňa Vytykáčová Ivan Ka šík Šárka Pitrová Ali A. Jasim Tags: Communication Source Type: research

Sensors, Vol. 21, Pages 5074: Scalable Data Model for Traffic Congestion Avoidance in a Vehicle to Cloud Infrastructure
tolea Traffic congestion experience in urban areas has negative impact on our daily lives by consuming our time and resources. Intelligent Transportation Systems can provide the necessary infrastructure to mitigate such challenges. In this paper, we propose a novel and scalable solution to model, store and control traffic data based on range query data structures (K-ary Interval Tree and K-ary Entry Point Tree) which allows data representation and handling in a way that better predicts and avoids traffic congestion in urban areas. Our experiments, validation scenarios, performance measurements and solution assessment w...
Source: Sensors - July 27, 2021 Category: Biotechnology Authors: Ioan Stan Vasile Suciu Rodica Potolea Tags: Article Source Type: research

Sensors, Vol. 21, Pages 5078: Can Intraoperative Intra-Articular Loads Predict Postoperative Knee Joint Laxity Following Total Knee Arthroplasty? A Cadaver Study with Smart Tibial Trays
This study aimed at correlating the intraoperative and postoperative metrics used to assess joint balance while also comparing joint loads obtained during passive assessment and active functional motions. Four experienced surgical fellows were assigned a fresh-frozen lower limb each to plan and perform posterior-stabilised TKA. An instrumented tibial insert measured intraoperative intra-articular loads. Specimens were then subjected to passive flexion–extension, open-chain extension, active squatting, and varus–valgus laxity tests on a validated knee simulator. Intra-articular loads were recorded using the inst...
Source: Sensors - July 27, 2021 Category: Biotechnology Authors: Darshan S. Shah Or çun Taylan Matthias Verstraete Pieter Berger Hilde Vandenneucker Lennart Scheys Tags: Communication Source Type: research

Sensors, Vol. 21, Pages 5073: Three-Dimensional Interferometric ISAR Imaging Algorithm Based on Cross Coherence Processing
ang Interferometric inverse synthetic aperture radar (InISAR) has received significant attention in three-dimensional (3D) imaging due to its applications in target classification and recognition. The traditional two-dimensional (2D) ISAR image can be interpreted as a filtered projection of a 3D target’s reflectivity function onto an image plane. Such a plane usually depends on unknown radar-target geometry and dynamics, which results in difficulty interpreting an ISAR image. Using the L-shape InISAR imaging system, this paper proposes a novel 3D target reconstruction algorithm based on Dechirp processing and 2D ...
Source: Sensors - July 27, 2021 Category: Biotechnology Authors: Qian Lv Shaozhe Zhang Tags: Article Source Type: research

Sensors, Vol. 21, Pages 5076: Analytical Model of Induction Machines with Multiple Cage Faults Using the Winding Tensor Approach
eda-Sanchez Induction machines (IMs) are one of the main sources of mechanical power in many industrial processes, especially squirrel cage IMs (SCIMs), due to their robustness and reliability. Their sudden stoppage due to undetected faults may cause costly production breakdowns. One of the most frequent types of faults are cage faults (bar and end ring segment breakages), especially in motors that directly drive high-inertia loads (such as fans), in motors with frequent starts and stops, and in case of poorly manufactured cage windings. A continuous monitoring of IMs is needed to reduce this risk, integrated in plant-...
Source: Sensors - July 27, 2021 Category: Biotechnology Authors: Javier Martinez-Roman Ruben Puche-Panadero Angel Sapena-Bano Carla Terron-Santiago Jordi Burriel-Valencia Manuel Pineda-Sanchez Tags: Article Source Type: research

Sensors, Vol. 21, Pages 5079: Atypical Gait Cycles in Parkinson ’s Disease
Sensors, Vol. 21, Pages 5079: Atypical Gait Cycles in Parkinson’s Disease Sensors doi: 10.3390/s21155079 Authors: Marco Ghislieri Valentina Agostini Laura Rizzi Marco Knaflitz Michele Lanotte It is important to find objective biomarkers for evaluating gait in Parkinson’s Disease (PD), especially related to the foot and lower leg segments. Foot-switch signals, analyzed through Statistical Gait Analysis (SGA), allow the foot-floor contact sequence to be characterized during a walking session lasting five-minutes, which includes turnings. Gait parameters were compared between 20 PD patients and 20 ...
Source: Sensors - July 27, 2021 Category: Biotechnology Authors: Marco Ghislieri Valentina Agostini Laura Rizzi Marco Knaflitz Michele Lanotte Tags: Article Source Type: research

Sensors, Vol. 21, Pages 5077: Sensor-Enabled Multi-Robot System for Automated Welding and in-Process Ultrasonic NDE
Anthony Gachagan The growth of the automated welding sector and emerging technological requirements of Industry 4.0 have driven demand and research into intelligent sensor-enabled robotic systems. The higher production rates of automated welding have increased the need for fast, robotically deployed Non-Destructive Evaluation (NDE), replacing current time-consuming manually deployed inspection. This paper presents the development and deployment of a novel multi-robot system for automated welding and in-process NDE. Full external positional control is achieved in real time allowing for on-the-fly motion correction, bas...
Source: Sensors - July 27, 2021 Category: Biotechnology Authors: Momchil Vasilev Charles N. MacLeod Charalampos Loukas Yashar Javadi Randika K. W. Vithanage David Lines Ehsan Mohseni Stephen Gareth Pierce Anthony Gachagan Tags: Article Source Type: research

Sensors, Vol. 21, Pages 5080: Accuracy and Uncertainty of Gradient Based Leak Localization Procedure for Liquid Transmission Pipelines
tek This paper describes issues of leakage localization in liquid transmission pipelines. It focuses on the standard leak localization procedure, which is based on the calculation of pressure gradients using pressure measurements captured along a pipeline. The procedure was verified in terms of an accuracy and uncertainty assessment of the resultant coordinate of a leak spot. An important aim of the verification was to assess the effectiveness of the procedure in the case of localization of low intensity leakages with a level of 0.25–2.00% of the nominal flow rate. An uncertainty assessment was carried out accord...
Source: Sensors - July 27, 2021 Category: Biotechnology Authors: Pawel Ostapkowicz Andrzej Bratek Tags: Article Source Type: research

Sensors, Vol. 21, Pages 5081: Convolver Design and Convolve-Accumulate Unit Design for Low-Power Edge Computing
Huang Convolution operations have a significant influence on the overall performance of a convolutional neural network, especially in edge-computing hardware design. In this paper, we propose a low-power signed convolver hardware architecture that is well suited for low-power edge computing. The basic idea of the proposed convolver design is to combine all multipliers’ final additions and their corresponding adder tree to form a partial product matrix (PPM) and then to use the reduction tree algorithm to reduce this PPM. As a result, compared with the state-of-the-art approach, our convolver design not only saves...
Source: Sensors - July 27, 2021 Category: Biotechnology Authors: Hsu-Yu Kao Xin-Jia Chen Shih-Hsu Huang Tags: Article Source Type: research

Sensors, Vol. 21, Pages 5082: Wearable Edge AI Applications for Ecological Environments
Ricardo A. R. Oliveira Ecological environments research helps to assess the impacts on forests and managing forests. The usage of novel software and hardware technologies enforces the solution of tasks related to this problem. In addition, the lack of connectivity for large data throughput raises the demand for edge-computing-based solutions towards this goal. Therefore, in this work, we evaluate the opportunity of using a Wearable edge AI concept in a forest environment. For this matter, we propose a new approach to the hardware/software co-design process. We also address the possibility of creating wearable edge AI, ...
Source: Sensors - July 27, 2021 Category: Biotechnology Authors: Mateus C. Silva Jonathan C. F. da Silva Saul Delabrida Andrea G. C. Bianchi S érvio P. Ribeiro Jorge S á Silva Ricardo A. R. Oliveira Tags: Article Source Type: research

Sensors, Vol. 21, Pages 5083: Virtual Reality-Based Framework to Simulate Control Algorithms for Robotic Assistance and Rehabilitation Tasks through a Standing Wheelchair
n S. Guevara The implementation of control algorithms oriented to robotic assistance and rehabilitation tasks for people with motor disabilities has been of increasing interest in recent years. However, practical implementation cannot be carried out unless one has the real robotic system availability. To overcome this drawback, this article presents the development of an interactive virtual reality (VR)-based framework that allows one to simulate the execution of rehabilitation tasks and robotic assistance through a robotic standing wheelchair. The virtual environment developed considers the kinematic and dynamic model...
Source: Sensors - July 27, 2021 Category: Biotechnology Authors: Jessica S. Ortiz Guillermo Palacios-Navarro V íctor H. Andaluz Bryan S. Guevara Tags: Article Source Type: research

Sensors, Vol. 21, Pages 5085: Comparative Experimental Investigation on Optimal Parametric Array Types
In this study, we share the results of an elaborate and comparative experimental investigation of these two driving methods. Comparisons are made and discussed in terms of the intensity of the generated secondary signal and its characteristics in the frequency domain. Based on these factors, we confirmed that the broadband PA was more suitable as the sound source of the low-frequency characteristic measurement system of acoustic materials. (Source: Sensors)
Source: Sensors - July 27, 2021 Category: Biotechnology Authors: Donghwan Jung Jiyoung Song Jeasoo Kim Jaehyuk Lee Tags: Communication Source Type: research

Sensors, Vol. 21, Pages 5084: Estimation of Earthquake Early Warning Parameters for Eastern Gulf of Corinth and Western Attica Region (Greece). First Results
ariou The main goal of an Earthquake Early Warning System (EEWS) is to alert before the arrival of damaging waves using the first seismic arrival as a proxy, thus becoming an important operational tool for real-time seismic risk management on a short timescale. EEWSs are based on the use of scaling relations between parameters measured on the initial portion of the seismic signal after the arrival of the first wave. To explore the plausibility of EEWSs around the Eastern Gulf of Corinth and Western Attica, amplitude and frequency-based parameters, such as peak displacement (Pd), the integral of squared velocity (IV&...
Source: Sensors - July 27, 2021 Category: Biotechnology Authors: Filippos Vallianatos Andreas Karakonstantis Nikolaos Sakelariou Tags: Article Source Type: research

Sensors, Vol. 21, Pages 5088: Water Content Monitoring in Water-in-Crude-Oil Emulsions Using an Ultrasonic Multiple-Backscattering Sensor
Tsuzuki Flávio Buiochi This work shows the application of an ultrasonic multiple-scattering sensor for monitoring water-in-petroleum emulsions. The sensor consists of a commercial ultrasonic transducer with an array of cylindrical scatterers placed in the near field. The scatterers are thin metal bars arranged in rows in front of the transducer. The backscattering signals were analyzed by calculating the wave energy and by a cross-correlation between signal segments; they were also used to determine the propagation velocity in the emulsions. The tests performed used emulsions with water volume concentrations ...
Source: Sensors - July 27, 2021 Category: Biotechnology Authors: Alberto L. Dur án Ediguer E. Franco Carlos A. B. Reyna Nicol ás Pérez Marcos S. G. Tsuzuki Fl ávio Buiochi Tags: Communication Source Type: research

Sensors, Vol. 21, Pages 5087: Comparison of Aerial Thermal Infrared Imagery and Helicopter Surveys of Bison (Bison bison) in Grand Canyon National Park, USA
L. Laake Aerial thermal infrared (TIR) surveys are an attractive option for estimating abundances of large mammals inhabiting extensive and heterogeneous terrain. Compared to standard helicopter or fixed-wing aerial surveys, TIR flights can be conducted at higher altitudes translating into greater spatial coverage and increased observer safety; however, monetary costs are much greater. Further, there is no consensus on whether TIR surveys offer improved detection. Consequently, we performed a study to compare results of a TIR and helicopter survey of bison (Bison bison) on the Powell Plateau in Grand Canyon National P...
Source: Sensors - July 27, 2021 Category: Biotechnology Authors: Jacob D. Hennig Kathryn A. Schoenecker Miranda L.N. Terwilliger Gregory W. Holm Jeffrey L. Laake Tags: Communication Source Type: research

Sensors, Vol. 21, Pages 5089: New Distributed Fibre Optic 3DSensor with Thermal Self-Compensation System: Design, Research and Field Proof Application inside Geotechnical Structure
This article is focused on the operational rules governing DFOS and proving their effectiveness in laboratory and geotechnical field applications. (Source: Sensors)
Source: Sensors - July 27, 2021 Category: Biotechnology Authors: Łukasz Bednarski Rafa ł Sieńko Marcin Grygierek Tomasz Howiacki Tags: Article Source Type: research

Sensors, Vol. 21, Pages 5090: Development of an Easy-to-Operate Underwater Raman System for Deep-Sea Cold Seep and Hydrothermal Vent In Situ Detection
n Xilin Zhang As a powerful in situ detection technique, Raman spectroscopy is becoming a popular underwater investigation method, especially in deep-sea research. In this paper, an easy-to-operate underwater Raman system with a compact design and competitive sensitivity is introduced. All the components, including the optical module and the electronic module, were packaged in an L362 × Φ172 mm titanium capsule with a weight of 20 kg in the air (about 12 kg in water). By optimising the laser coupling mode and focusing lens parameters, a competitive sensitivity was achieved with the detection limit of SO42&m...
Source: Sensors - July 27, 2021 Category: Biotechnology Authors: Qingsheng Liu Jinjia Guo Wangquan Ye Kai Cheng Fujun Qi Ronger Zheng Zhilei Sun Xilin Zhang Tags: Communication Source Type: research

Sensors, Vol. 21, Pages 5092: EEG-Based Emotion Recognition by Convolutional Neural Network with Multi-Scale Kernels
ang Lee Besides facial or gesture-based emotion recognition, Electroencephalogram (EEG) data have been drawing attention thanks to their capability in countering the effect of deceptive external expressions of humans, like faces or speeches. Emotion recognition based on EEG signals heavily relies on the features and their delineation, which requires the selection of feature categories converted from the raw signals and types of expressions that could display the intrinsic properties of an individual signal or a group of them. Moreover, the correlation or interaction among channels and frequency bands also contain cruci...
Source: Sensors - July 27, 2021 Category: Biotechnology Authors: Tran-Dac-Thinh Phan Soo-Hyung Kim Hyung-Jeong Yang Guee-Sang Lee Tags: Article Source Type: research

Sensors, Vol. 21, Pages 5093: Nonlinear Guided-Wave Mixing for Condition Monitoring of Bolted Joints
This study presents a theoretical development and experimental investigation into nonlinear guided-wave mixing for integrity monitoring of bolted joints in plates. Combinational harmonics generated due to nonlinear Lamb wave mixing and contact acoustic nonlinearity at the bolted joints were used to evaluate the applied torque level in the joint. The area of the power spectral density in the region of the sum combinational harmonic bandwidth is found to be highly correlated to the applied torque level at the joint. Moreover, the effect of the number of cycles and thus the time duration of the excitation is investigated. The...
Source: Sensors - July 27, 2021 Category: Biotechnology Authors: Juan Carlos Pineda Allen Ching Tai Ng Tags: Article Source Type: research

Sensors, Vol. 21, Pages 5091: Microneedle Array Electrode-Based Wearable EMG System for Detection of Driver Drowsiness through Steering Wheel Grip
In this study, a driver drowsiness detection system was developed by investigating the electromyography (EMG) signal of the muscles involved in steering wheel grip during driving. The EMG signal was measured from the forearm position of the driver during a one-hour interactive driving task. Additionally, the participant’s drowsiness level was also measured to investigate the relationship between muscle activity and driver’s drowsiness level. Frequency domain analysis was performed using the short-time Fourier transform (STFT) and spectrogram to assess the frequency response of the resultant signal. An EMG signa...
Source: Sensors - July 27, 2021 Category: Biotechnology Authors: Afraiz Tariq Satti Jiyoun Kim Eunsurk Yi Hwi-young Cho Sungbo Cho Tags: Communication Source Type: research

Sensors, Vol. 21, Pages 5086: Needs, Requirements and a Concept of a Tool Condition Monitoring System for the Aerospace Industry
obert Fularski In this paper, we describe the needs and specific requirements of the aerospace industry in the field of metal machining; specifically, the concept of an edge-computing-based production supervision system for the aerospace industry using a tool and cutting process condition monitoring system. The new concept was developed based on experience gained during the implementation of research projects in Poland’s Aviation Valley at aerospace plants such as Pratt & Whitney and Lockheed Martin. Commercial tool condition monitoring (TCM) and production monitoring systems do not effectively meet t...
Source: Sensors - July 27, 2021 Category: Biotechnology Authors: Sebastian Bombi ński Joanna Kossakowska Miros ław Nejman Rodolfo E. Haber Fernando Casta ño Robert Fularski Tags: Article Source Type: research

Sensors, Vol. 21, Pages 5049: Distributed Static and Dynamic Strain Measurements in Polymer Optical Fibers by Rayleigh Scattering
Aldo Minardo We demonstrate the use of a graded-index perfluorinated optical fiber (GI-POF) for distributed static and dynamic strain measurements based on Rayleigh scattering. The system is based on an amplitude-based phase-sensitive Optical Time-Domain Reflectometry (ϕ-OTDR) configuration, operated at the unconventional wavelength of 850 nm. Static strain measurements have been carried out at a spatial resolution of 4 m and for a strain up to 3.5% by exploiting the increase of the backscatter Rayleigh coefficient consequent to the application of a tensile strain, while vibration/acoustic measurements have been de...
Source: Sensors - July 26, 2021 Category: Biotechnology Authors: Agnese Coscetta Ester Catalano Enis Cerri Ricardo Oliveira Lucia Bilro Luigi Zeni Nunzio Cennamo Aldo Minardo Tags: Communication Source Type: research

Sensors, Vol. 21, Pages 5054: Performance Evaluation of Bundle Adjustment with Population Based Optimization Algorithms Applied to Panoramic Image Stitching
acute;cius F. Vidal The image stitching process is based on the alignment and composition of multiple images that represent parts of a 3D scene. The automatic construction of panoramas from multiple digital images is a technique of great importance, finding applications in different areas such as remote sensing and inspection and maintenance in many work environments. In traditional automatic image stitching, image alignment is generally performed by the Levenberg–Marquardt numerical-based method. Although these traditional approaches only present minor flaws in the final reconstruction, the final result is not a...
Source: Sensors - July 26, 2021 Category: Biotechnology Authors: Maria Aguiar Tiago Alves Leonardo Hon ório Ivo Junior Vin ícius F. Vidal Tags: Article Source Type: research

Sensors, Vol. 21, Pages 5052: User Experience in Social Robots
This study emphasizes the need for robot developers to acquire the required theoretical and practical knowledge on how to perform a successful UX evaluation. (Source: Sensors)
Source: Sensors - July 26, 2021 Category: Biotechnology Authors: Elaheh Shahmir Shourmasti Ricardo Colomo-Palacios Harald Holone Selina Demi Tags: Systematic Review Source Type: research

Sensors, Vol. 21, Pages 5055: An Improved Calibration Method for the IMU Biases Utilizing KF-Based AdaGrad Algorithm
g Cai In the field of high accuracy strapdown inertial navigation system (SINS), the inertial measurement unit (IMU) biases can severely affect the navigation accuracy. Traditionally we use Kalman filter (KF) to estimate those biases. However, KF is an unbiased estimation method based on the assumption of Gaussian white noise (GWN) while IMU sensors noise is irregular. Kalman filtering will no longer be accurate when the sensor’s noise is irregular. In order to obtain the optimal solution of the IMU biases, this paper proposes a novel method for the calibration of IMU biases utilizing the KF-based AdaGrad algorit...
Source: Sensors - July 26, 2021 Category: Biotechnology Authors: Zeyang Wen Gongliu Yang Qingzhong Cai Tags: Article Source Type: research

Sensors, Vol. 21, Pages 5050: Analysis of Reliability of Strain Measurements Made with the Fiber Bragg Grating Sensor Rosettes Embedded in a Polymer Composite Material
Fedorov The results of strain measuring experiments, with the help of rosettes consisting of fiber Bragg grating sensors (FBG) embedded at the manufacturing stage in a polymer composite material are considered in this paper. The samples were made by the direct pressing method from fiberglass prepregs. A cross-shaped sample was tested under loading conditions corresponding to a complex stress state. A variant of strain calculations based on experimental data is discussed. The calculations were performed under the assumption of a uniaxial stress state in an optical fiber embedded in the material. The obtained results pro...
Source: Sensors - July 26, 2021 Category: Biotechnology Authors: Valerii Matveenko Natalia Kosheleva Grigorii Serovaev Andrey Fedorov Tags: Article Source Type: research

Sensors, Vol. 21, Pages 5056: Passive Electrical Damping of a Quartz Tuning Fork as a Path to Fast Resonance Tracking in QEPAS
ore Vicet In Quartz-Enhanced PhotoAcoustic Spectroscopy (QEPAS) gas sensors, the acoustic wave is detected by the piezoelectric Quartz Tuning Fork (QTF). Due to its high-quality factor, the QTF can detect very low-pressure variations, but its resonance can also be affected by the environmental variations (temperature, humidity, …), which causes an unwanted signal drift. Recently, we presented the RT-QEPAS technique that consistently corrects the signal drift by continuously measuring the QTF resonance. In this article, we present an improvement of RT-QEPAS to fasten the QTF characterization time by adding a pass...
Source: Sensors - July 26, 2021 Category: Biotechnology Authors: Roman Rousseau Diba Ayache Wioletta Trzpil Michael Bahriz Aurore Vicet Tags: Article Source Type: research

Sensors, Vol. 21, Pages 5053: Combining IOTA and Attribute-Based Encryption for Access Control in the Internet of Things
asahara Unauthorized resource access represents a typical security threat in the Internet of things (IoT), while distributed ledger technologies (e.g., blockchain and IOTA) hold great promise to address this threat. Although blockchain-based IoT access control schemes have been the most popular ones, they suffer from several significant limitations, such as high monetary cost and low throughput of processing access requests. To overcome these limitations, this paper proposes a novel IoT access control scheme by combining the fee-less IOTA technology and the Ciphertext-Policy Attribute-Based Encryption (CP-ABE) technolo...
Source: Sensors - July 26, 2021 Category: Biotechnology Authors: Yuanyu Zhang Ruka Nakanishi Masahiro Sasabe Shoji Kasahara Tags: Article Source Type: research

Sensors, Vol. 21, Pages 5058: Full-Field Bridge Deflection Monitoring with Off-Axis Digital Image Correlation
ng Wang Video deflectometer based on using off-axis digital image correlation (DIC) has emerged as a robust non-contact optical tool for deflection measurements of bridges. In practice, a video deflectometer often needs to measure the deflections at multiple positions of the bridge. The existing 2D-DIC-based measurement methods usually use a laser rangefinder to measure the distance from each point to the camera to obtain the scale factor for the point. It is only suitable for the deflection measurements of a few points since manually measuring distances for a large number of points is time consuming and impractical. I...
Source: Sensors - July 26, 2021 Category: Biotechnology Authors: Long Tian Jianhui Zhao Bing Pan Zhaoyang Wang Tags: Article Source Type: research

Sensors, Vol. 21, Pages 5060: Optimizing the Performance of Pure ALOHA for LoRa-Based ESL
ing Jin (1) Background: The scientific development in the field of industrialization demands the automization of electronic shelf labels (ESLs). COVID-19 has limited the manpower responsible for the frequent updating of the ESL system. The current ESL uses QR (quick response) codes, NFC (near-field communication), and RFID (radio-frequency identification). These technologies have a short range or need more manpower. LoRa is one of the prominent contenders in this category as it provides long-range connectivity with less energy harvesting and location tracking. It uses many gateways (GWs) to transmit the same data packe...
Source: Sensors - July 26, 2021 Category: Biotechnology Authors: Malak Abid Ali Khan Hongbin Ma Syed Muhammad Aamir Ying Jin Tags: Article Source Type: research

Sensors, Vol. 21, Pages 5062: CACLA-Based Trajectory Tracking Guidance for RLV in Terminal Area Energy Management Phase
biao Xu This paper focuses on the trajectory tracking guidance problem for the Terminal Area Energy Management (TAEM) phase of the Reusable Launch Vehicle (RLV). Considering the continuous state and action space of this guidance problem, the Continuous Actor–Critic Learning Automata (CACLA) is applied to construct the guidance strategy of RLV. Two three-layer neuron networks are used to model the critic and actor of CACLA, respectively. The weight vectors of the critic are updated by the model-free Temporal Difference (TD) learning algorithm, which is improved by eligibility trace and momentum factor. The weight ...
Source: Sensors - July 26, 2021 Category: Biotechnology Authors: Xuejing Lan Zhifeng Tan Tao Zou Wenbiao Xu Tags: Communication Source Type: research

Sensors, Vol. 21, Pages 5061: Transformations in the Photogrammetric Co-Processing of Thermal Infrared Images and RGB Images
velka The photogrammetric processing of thermal infrared (TIR) images deals with several difficulties. TIR images ordinarily have low-resolution and the contrast of the images is very low. These factors strongly complicate the photogrammetric processing, especially when a modern structure from motion method is used. These factors can be avoided by a certain co-processing method of TIR and RGB images. Two of the solutions of co-processing were suggested by the authors and are presented in this article. Each solution requires a different type of transformation–plane transformation and spatial transformation. Both t...
Source: Sensors - July 26, 2021 Category: Biotechnology Authors: Adam Dlesk Karel Vach Karel Pavelka Tags: Article Source Type: research

Sensors, Vol. 21, Pages 5059: Voltammetric E-Tongue for Honey Adulteration Detection
ian The aim of this study is to establish the usefulness of an electronic tongue based on cyclic voltammetry e-tongue using five working electrodes (gold, silver, copper, platinum and glass) in honey adulteration detection. Authentic honey samples of different botanical origin (acacia, tilia, sunflower, polyfloral and raspberry) were adulterated with agave, maple, inverted sugar, corn and rice syrups in percentages of 5%, 10%, 20% and 50%. The silver and copper electrodes provided the clearest voltammograms, the differences between authentic and adulterated honey samples being highlighted by the maximum current intensi...
Source: Sensors - July 26, 2021 Category: Biotechnology Authors: Paula Ciursa Mircea Oroian Tags: Article Source Type: research

Sensors, Vol. 21, Pages 5057: A Spectrum Correction Algorithm Based on Beat Signal of FMCW Laser Ranging System
ang Pan The accuracy of target distance obtained by a frequency modulated continuous wave (FMCW) laser ranging system is often affected by factors such as white Gaussian noise (WGN), spectrum leakage, and the picket fence effect. There are some traditional spectrum correction algorithms to solve the problem above, but the results are unsatisfactory. In this article, a decomposition filtering-based dual-window correction (DFBDWC) algorithm is proposed to alleviate the problem caused by these factors. This algorithm reduces the influence of these factors by utilizing a decomposition filtering, dual-window in time domain ...
Source: Sensors - July 26, 2021 Category: Biotechnology Authors: Yi Hao Ping Song Xuanquan Wang Zhikang Pan Tags: Article Source Type: research

Sensors, Vol. 21, Pages 5063: NiO Nanoparticles for Electrochemical Insulin Detection
In this study, carbon electrode with electrodeposited NiO nanoparticles was selected as a suitable electrode material for insulin determination. The morphology and surface composition were studied by scanning electron microscopy (SEM), energy dispersive X-ray (EDX) spectroscopy, and X-ray photoelectron spectroscopy (XPS). For a better understanding of insulin determination on NiO-modified electrodes, the mechanism of electrochemical reaction and the kinetic parameters were studied. They were calculated from both voltammetric and amperometric measurements. The modified carbon electrode displayed a wide linear range from 600...
Source: Sensors - July 26, 2021 Category: Biotechnology Authors: Jana Shepa Ivana Šišoláková Marek Vojtko Libu še Trnková G éza Nagy Iveta Maska ľová Andrej Ori ňak Ren áta Oriňaková Tags: Article Source Type: research

Sensors, Vol. 21, Pages 5064: Rapid Prototyping of Inertial MEMS Devices through Structural Optimization
aghin In this paper, we propose a novel design and optimization environment for inertial MEMS devices based on a computationally efficient schematization of the structure at the a device level. This allows us to obtain a flexible and efficient design optimization tool, particularly useful for rapid device prototyping. The presented design environment—feMEMSlite—handles the parametric generation of the structure geometry, the simulation of its dynamic behavior, and a gradient-based layout optimization. The methodology addresses the design of general inertial MEMS devices employing suspended proof masses, in ...
Source: Sensors - July 26, 2021 Category: Biotechnology Authors: Daniele Giannini Giacomo Bonaccorsi Francesco Braghin Tags: Article Source Type: research

Sensors, Vol. 21, Pages 5065: Locating Ships Using Time Reversal and Matrix Pencil Method by Their Underwater Acoustic Signals
s Gutierrez This paper presents a technique, based on the matrix pencil method (MPM), for the compression of underwater acoustic signals produced by boat engines. The compressed signal, represented by its complex resonance expansion, is intended to be sent over a low-bit-rate wireless communication channel. We demonstrate that the method can provide data compression greater than 60%, ensuring a correlation greater than 93% between the reconstructed and the original signal, at a sampling frequency of 2.2 kHz. Once the signal was reconstituted, a localization process was carried out with the time reversal method (TR) usi...
Source: Sensors - July 26, 2021 Category: Biotechnology Authors: Daniel Chaparro-Arce Sergio Gutierrez Andres Gallego Cesar Pedraza Felix Vega Carlos Gutierrez Tags: Article Source Type: research

Sensors, Vol. 21, Pages 5041: Review on Comparison of Different Energy Storage Technologies Used in Micro-Energy Harvesting, WSNs, Low-Cost Microelectronic Devices: Challenges and Recommendations
This study reviews supercapacitors as a better alternative of batteries in low-cost electronic devices, WSNs, and MEH systems. (Source: Sensors)
Source: Sensors - July 26, 2021 Category: Biotechnology Authors: Amna Riaz Mahidur R. Sarker Mohamad Hanif Md Saad Ramizi Mohamed Tags: Review Source Type: research

Sensors, Vol. 21, Pages 5042: Diffusion Model of Preemptive-Resume Priority Systems and Its Application to Performance Evaluation of SDN Switches
We present here a diffusion approximation of priority queues and apply it to build a more detailed model of SDN switch where packets returned by the central controller have higher priority than other packets. (Source: Sensors)
Source: Sensors - July 26, 2021 Category: Biotechnology Authors: Tomasz Nycz Tadeusz Czach órski Monika Nycz Tags: Article Source Type: research

Sensors, Vol. 21, Pages 5043: A Review on Mental Stress Assessment Methods Using EEG Signals
Al-Nashash Mental stress is one of the serious factors that lead to many health problems. Scientists and physicians have developed various tools to assess the level of mental stress in its early stages. Several neuroimaging tools have been proposed in the literature to assess mental stress in the workplace. Electroencephalogram (EEG) signal is one important candidate because it contains rich information about mental states and condition. In this paper, we review the existing EEG signal analysis methods on the assessment of mental stress. The review highlights the critical differences between the research findings and ...
Source: Sensors - July 26, 2021 Category: Biotechnology Authors: Rateb Katmah Fares Al-Shargie Usman Tariq Fabio Babiloni Fadwa Al-Mughairbi Hasan Al-Nashash Tags: Review Source Type: research

Sensors, Vol. 21, Pages 5044: LoRa Communications as an Enabler for Internet of Drones towards Large-Scale Livestock Monitoring in Rural Farms
ah Abdullah Currently, smart farming is considered an effective solution to enhance the productivity of farms; thereby, it has recently received broad interest from service providers to offer a wide range of applications, from pest identification to asset monitoring. Although the emergence of digital technologies, such as the Internet of Things (IoT) and low-power wide-area networks (LPWANs), has led to significant advances in the smart farming industry, farming operations still need more efficient solutions. On the other hand, the utilization of unmanned aerial vehicles (UAVs), also known as drones, is growing rapidly...
Source: Sensors - July 26, 2021 Category: Biotechnology Authors: Mehran Behjati Aishah Binti Mohd Noh Haider A. H. Alobaidy Muhammad Aidiel Zulkifley Rosdiadee Nordin Nor Fadzilah Abdullah Tags: Article Source Type: research

Sensors, Vol. 21, Pages 5045: Fast Sensing of Hydrogen Cyanide (HCN) Vapors Using a Hand-Held Ion Mobility Spectrometer with Nonradioactive Ionization Source
This study was focused toward quick detection and quantification of HCN in air using time-of-flight ion mobility spectrometry (ToF IMS). Results obtained clearly indicate that IMS can rapidly detect HCN at sub-ppmv levels in air. Ion mobility spectrometric response was obtained in the negative ion mode and presented one single distinct product ion, at reduced ion mobility K0 of 2.38 cm2 V−1 s−1. Our study demonstrated that by using a miniaturized commercial IMS system with nonradioactive ionization source model LCD-3.2E (Smiths Detection Ltd., London, UK), one can easily measure HCN at concentrations of 0.1 ppm...
Source: Sensors - July 26, 2021 Category: Biotechnology Authors: Victor Bocos-Bintintan Ileana Andreea Ratiu Tags: Article Source Type: research