Sensors, Vol. 24, Pages 2590: An Autocollimator Axial Measurement Method Based on the Strapdown Inertial Navigation System
anghong Jiang
Autocollimators are widely used optical axis-measuring tools, but their measurement errors increase significantly when measuring under non-leveled conditions and they have a limited measurement range due to the limitations of the measurement principle. To realize axis measurement under non-leveled conditions, this paper proposes an autocollimator axis measurement method based on the strapdown inertial navigation system (SINS). First, the measurement model of the system was established. This model applies the SINS to measure the change in attitude of the autocollimator. The autocollimator was then applied ...
Source: Sensors - April 18, 2024 Category: Biotechnology Authors: Wenjia Ma Jianrong Li Shaojin Liu Yan Han Xu Liu Zhiqian Wang Changhong Jiang Tags: Article Source Type: research
Sensors, Vol. 24, Pages 2589: ST-TGR: Spatio-Temporal Representation Learning for Skeleton-Based Teaching Gesture Recognition
ngming Wang
Teaching gesture recognition is a technique used to recognize the hand movements of teachers in classroom teaching scenarios. This technology is widely used in education, including for classroom teaching evaluation, enhancing online teaching, and assisting special education. However, current research on gesture recognition in teaching mainly focuses on detecting the static gestures of individual students and analyzing their classroom behavior. To analyze the teacher’s gestures and mitigate the difficulty of single-target dynamic gesture recognition in multi-person teaching scenarios, this pape...
Source: Sensors - April 18, 2024 Category: Biotechnology Authors: Zengzhao Chen Wenkai Huang Hai Liu Zhuo Wang Yuqun Wen Shengming Wang Tags: Article Source Type: research
Sensors, Vol. 24, Pages 2591: Improving Graph Convolutional Network with Learnable Edge Weights and Edge-Node Co-Embedding for Graph Anomaly Detection
ngwang Li
The era of Industry 4.0 is gradually transforming our society into a data-driven one, which can help us uncover valuable information from accumulated data, thereby improving the level of social governance. The detection of anomalies, is crucial for maintaining societal trust and fairness, yet it poses significant challenges due to the ubiquity of anomalies and the difficulty in identifying them accurately. This paper aims to enhance the performance of the current Graph Convolutional Network (GCN)-based Graph Anomaly Detection (GAD) algorithm on datasets with extremely low proportions of anomalous labels. This...
Source: Sensors - April 18, 2024 Category: Biotechnology Authors: Xiao Tan Jianfeng Yang Zhengang Zhao Jinsheng Xiao Chengwang Li Tags: Article Source Type: research
Sensors, Vol. 24, Pages 2593: Helicopter Planet Gear Rim Crack Diagnosis and Trending Using Cepstrum Editing Enhanced with Deconvolution
Blunt
Detecting gear rim fatigue cracks using vibration signal analysis is often a challenging task, which typically requires a series of signal processing steps to detect and enhance fault features. This task becomes even harder in helicopter planetary gearboxes due to the complex interactions between different gear sets and the presence of vibration from sources other than the planetary gear set. In this paper, we propose an effectual processing algorithm to isolate and enhance rim crack features and to trend crack growth in planet gears. The algorithm is based on using cepstrum editing (or liftering) of the hunting-...
Source: Sensors - April 18, 2024 Category: Biotechnology Authors: Nader Sawalhi Wenyi Wang David Blunt Tags: Article Source Type: research
Sensors, Vol. 24, Pages 2592: Learning-Based Hierarchical Decision-Making Framework for Automatic Driving in Incompletely Connected Traffic Scenarios
Zirui Li
The decision-making algorithm serves as a fundamental component for advancing the level of autonomous driving. The end-to-end decision-making algorithm has a strong ability to process the original data, but it has grave uncertainty. However, other learning-based decision-making algorithms rely heavily on ideal state information and are entirely unsuitable for autonomous driving tasks in real-world scenarios with incomplete global information. Addressing this research gap, this paper proposes a stable hierarchical decision-making framework with images as the input. The first step of the framework is a model-ba...
Source: Sensors - April 18, 2024 Category: Biotechnology Authors: Fan Yang Xueyuan Li Qi Liu Xiangyu Li Zirui Li Tags: Article Source Type: research
Sensors, Vol. 24, Pages 2595: Action Recognition of Taekwondo Unit Actions Using Action Images Constructed with Time-Warped Motion Profiles
This study introduces a novel action recognition model tailored for Taekwondo unit actions, utilizing joint-motion data acquired via wearable inertial measurement unit (IMU) sensors. The utilization of IMU sensor-measured motion data facilitates the capture of the intricate and rapid movements characteristic of Taekwondo techniques. The model, underpinned by a conventional convolutional neural network (CNN)-based image classification framework, synthesizes action images to represent individual Taekwondo unit actions. These action images are generated by mapping joint-motion profiles onto the RGB color space, thus encapsula...
Source: Sensors - April 18, 2024 Category: Biotechnology Authors: Junghwan Lim Chenglong Luo Seunghun Lee Young Eun Song Hoeryong Jung Tags: Article Source Type: research
Sensors, Vol. 24, Pages 2594: Self-Diagnostic and Self-Compensation Methods for Resistive Displacement Sensors Tailored for in-Field Implementation
rrari
This paper presents a suitably general model for resistive displacement sensors where the model parameters depend on the current sensor conditions, thereby capturing wearout and failure, and proposes a novel fault detection method that can be seamlessly applied during sensor operation, providing self-diagnostic capabilities. On the basis of the estimation of model parameters, an innovative self-compensation method is derived to increase the accuracy of sensors subject to progressive wearout. The proposed model and methods have been validated by both numerical simulations and experimental tests on two real resisti...
Source: Sensors - April 18, 2024 Category: Biotechnology Authors: Federico Mazzoli Davide Alghisi Vittorio Ferrari Tags: Article Source Type: research
Sensors, Vol. 24, Pages 2568: Modular and Cost-Effective Computed Tomography Design
We present a modular and cost-effective gamma ray computed tomography system for multiphase flow investigations in industrial apparatuses. It mainly comprises a 137Cs isotopic source and an in-house-assembled detector arc, with a total of 16 scintillation detectors, offering a quantum efficiency of approximately 75% and an active area of 10 × 10 mm2 each. The detectors are operated in pulse mode to exclude scattered gamma photons from counting by using a dual-energy discrimination stage. Flexible application of the computed tomography system, i.e., for various object sizes and densities, is provided by an ela...
Source: Sensors - April 17, 2024 Category: Biotechnology Authors: Andr é Bieberle Rainer Hoffmann Alexander D öß Eckhard Schleicher Uwe Hampel Tags: Article Source Type: research
Sensors, Vol. 24, Pages 2570: Electrochemical Detection of Bisphenol A Based on Gold Nanoparticles/Multi-Walled Carbon Nanotubes: Applications on Glassy Carbon and Screen Printed Electrodes
arballo
Bisphenol A (BPA) has been classified as an endocrine-disrupting substance that may cause adverse effects on human health and the environment. The development of simple and sensitive electrochemical biosensors is crucial for the rapid and effective quantitative determination of BPA. This work presents a study on electrochemical sensors utilizing gold nanoparticle-modified multi-walled carbon nanotubes (CNT/AuNPs). Glassy carbon electrodes (GCEs) and screen-printed electrodes (SPEs) were conveniently modified and used for BPA detection. AuNPs were electrodeposited onto the CNT-modified electrodes using the galva...
Source: Sensors - April 17, 2024 Category: Biotechnology Authors: Maximina Luis-Sunga Soledad Carinelli Gonzalo Garc ía Jos é Luis González-Mora Pedro A. Salazar-Carballo Tags: Article Source Type: research
Sensors, Vol. 24, Pages 2571: LazyFrog: Advancing Security and Efficiency in Commercial Wireless Charging with Adaptive Frequency Hopping
This study tackles two core issues: the increasing hardware requirements for billing system authentication protocols and the interception of wireless charging signals by unauthorized users, leading to power theft and subsequent losses. To address these challenges, we propose a mechanism termed “LazyFrog”. This mechanism dynamically adjusts the frequency hopping schedule, activating frequency changes only in response to detected threats during remote charging or upon identifying unauthorized access attempts. The proposed mechanism compares the expected power reception at the device with the actua...
Source: Sensors - April 17, 2024 Category: Biotechnology Authors: Sungkyu Ahn Hyelim Jung Ki-Woong Park Tags: Article Source Type: research
Sensors, Vol. 24, Pages 2572: Error Model for the Assimilation of All-Sky FY-4A/AGRI Infrared Radiance Observations
In this study, we introduce two cloud-affected (Ca) indices to quantify the impact of cloud amount and establish dynamic observation error models to address biases between O−B and Gaussian distributions when assimilating all-sky data from FY-4A/AGRI observations. For each Ca index, we evaluate two dynamic observation error models: a two-segment and a three-segment linear model. Our findings indicate that the three-segment linear model we propose better conforms to the statistical characteristics of FY-4A/AGRI observations and improves the Gaussianity of the O−B probability density function. Dyna...
Source: Sensors - April 17, 2024 Category: Biotechnology Authors: Dongchuan Pu Yali Wu Tags: Article Source Type: research
Sensors, Vol. 24, Pages 2574: A Sensor-Based Upper Limb Treatment in Hemiplegic Patients: Results from a Randomized Pilot Study
This study aims to evaluate the feasibility of using the Gloreha Aria (R-Lead), a sensor-based upper limb in-hospital rehabilitation, compared with conventional physiotherapist-led training in subacute hemiplegic patients. Twenty-one patients were recruited and randomised 1:1 to a sensor-based group (treatment group TG) or a conventional group (control group, CG). All patients performed 30 sessions of 30 min each of dedicated upper limb rehabilitation. The Fugl–Meyer Assessment for Upper Extremity (FMA-UE) was the primary evaluation., both as a motor score and as individual items. Secondary evaluations were F...
Source: Sensors - April 17, 2024 Category: Biotechnology Authors: Fabio Vanoglio Laura Comini Marta Gaiani Gian Pietro Bonometti Alberto Luisa Palmira Bernocchi Tags: Article Source Type: research
Sensors, Vol. 24, Pages 2573: Cluster-Based Pairwise Contrastive Loss for Noise-Robust Speech Recognition
Kim
This paper addresses a joint training approach applied to a pipeline comprising speech enhancement (SE) and automatic speech recognition (ASR) models, where an acoustic tokenizer is included in the pipeline to leverage the linguistic information from the ASR model to the SE model. The acoustic tokenizer takes the outputs of the ASR encoder and provides a pseudo-label through K-means clustering. To transfer the linguistic information, represented by pseudo-labels, from the acoustic tokenizer to the SE model, a cluster-based pairwise contrastive (CBPC) loss function is proposed, which is a self-supervised contrastive...
Source: Sensors - April 17, 2024 Category: Biotechnology Authors: Geon Woo Lee Hong Kook Kim Tags: Article Source Type: research
Sensors, Vol. 24, Pages 2575: Fault Diagnosis for Reducers Based on a Digital Twin
i Zheng
A new method based on a digital twin is proposed for fault diagnosis, in order to compensate for the shortcomings of the existing methods for fault diagnosis modeling, including the single fault type, low similarity, and poor visual effect of state monitoring. First, a fault diagnosis test platform is established to analyze faults under constant and variable speed conditions. Then, the obtained data are integrated into the Unity3D platform to realize online diagnosis and updated with real-time working status data. Finally, an industrial test of the digital twin model is conducted, allowing for its comparison wi...
Source: Sensors - April 17, 2024 Category: Biotechnology Authors: Weimin Liu Bin Han Aiyun Zheng Zhi Zheng Tags: Article Source Type: research
Sensors, Vol. 24, Pages 2576: A Single-Longitudinal-Mode S + C Band Wavelength-Tunable Fiber Laser
ang
An external cavity wavelength-fiber ring laser (ECWTFL) based on a semiconductor optical amplifier and a combined wavelength scanning filter in the Littrow configuration is proposed and experimentally demonstrated. With the benefit of the combination of an external cavity wavelength filter and a Lyot filter, the laser achieves a single-mode narrow linewidth output with a linewidth of 1.75 kHz. The wavelength tuning range reaches 133 nm, covering the entire S + C band. The proposed ECWTFL is used for demodulation of a fiber EFPI sensor; the result shows that the proposed ECWTFL has the ability to demodulate the smal...
Source: Sensors - April 17, 2024 Category: Biotechnology Authors: Da Liu Yi Jiang Tags: Communication Source Type: research
