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1.
Sensors (Basel) ; 23(21)2023 Oct 24.
Article in English | MEDLINE | ID: mdl-37960364

ABSTRACT

Point cloud-based retrieval for place recognition is essential in robotic applications like autonomous driving or simultaneous localization and mapping. However, this remains challenging in complex real-world scenes. Existing methods are sensitive to noisy, low-density point clouds and require extensive storage and computation, posing limitations for hardware-limited scenarios. To overcome these challenges, we propose LWR-Net, a lightweight place recognition network for efficient and robust point cloud retrieval in noisy, low-density conditions. Our approach incorporates a fast dilated sampling and grouping module with a residual MLP structure to learn geometric features from local neighborhoods. We also introduce a lightweight attentional weighting module to enhance global feature representation. By utilizing the Generalized Mean pooling structure, we aggregated the global descriptor for point cloud retrieval. We validated LWR-Net's efficiency and robustness on the Oxford robotcar dataset and three in-house datasets. The results demonstrate that our method efficiently and accurately retrieves matching scenes while being more robust to variations in point density and noise intensity. LWR-Net achieves state-of-the-art accuracy and robustness with a lightweight model size of 0.4M parameters. These efficiency, robustness, and lightweight advantages make our network highly suitable for robotic applications relying on point cloud-based place recognition.

2.
Sensors (Basel) ; 22(18)2022 Sep 10.
Article in English | MEDLINE | ID: mdl-36146213

ABSTRACT

The pedestrian stride-length estimation is a crucial piece of personal behavior data for many smartphone applications, such as health monitoring and indoor location. The performance of the present stride-length algorithms is suitable for simple gaits and single scenes, but when applied to sophisticated gaits or heterogeneous devices, their inaccuracy varies dramatically. This paper proposes an efficient learning-based stride-length estimation model using a smartphone to obtain the correct stride length. The model uses adaptive learning to extract different elements for changing and recognition tasks, including Long Short-Term Memory (LSTM) and Convolutional Neural Network (CNN) modules. The direct fusion method maps the eigenvectors to the appropriate stride length after combining the features from the learning modules. We presented an online learning module to update the model to increase the SLE model's generalization. Extensive experiments are conducted with heterogeneous devices or users, various gaits, and switched scenarios. The results confirm that the proposed method outperforms other state-of-the-art methods and achieves an average 4.26% estimation error rate in various environments.


Subject(s)
Gait , Pedestrians , Humans , Algorithms , Neural Networks, Computer , Smartphone
3.
Talanta ; 236: 122892, 2022 Jan 01.
Article in English | MEDLINE | ID: mdl-34635271

ABSTRACT

Reactive oxygen species (ROS) play an essential role in regulating various physiological functions of living organisms. Superoxide anion (O2-.), one kind of ROS, is the single-electron reduction product of oxygen molecules, which mainly exists in plants and animals, and is closely related to many inflammatory diseases. In the field of biomedicine, with the deepening understanding of superoxide anion, more and more detection methods have been developed. This review mainly introduces the detection techniques for superoxide anion in recent years.


Subject(s)
Plants , Superoxides , Animals , Reactive Oxygen Species
4.
Chem Commun (Camb) ; 57(8): 1018-1021, 2021 Feb 01.
Article in English | MEDLINE | ID: mdl-33404554

ABSTRACT

A novel surface-enhanced Raman scattering (SERS) nanoprobe based on a reactive strategy was designed for the first time to determine the concentration of superoxide anion radical (O2˙-) produced from titanium dioxide by a UV radiation process. A limit of detection (LOD) for O2˙- of 9.0 nmol L-1 could be attained.


Subject(s)
Spectrum Analysis, Raman/methods , Sunscreening Agents/chemistry , Superoxides/chemistry , Titanium/chemistry , Ultraviolet Rays , Limit of Detection , Metal Nanoparticles , Silver
5.
Nanoscale ; 12(7): 4719-4728, 2020 Feb 20.
Article in English | MEDLINE | ID: mdl-32049072

ABSTRACT

The design and fabrication of economically viable anode catalysts for the methanol oxidation reaction (MOR) have been challenging issues in direct methanol fuel cells (DMFCs) over the decades. In this work, a composite electrochemical catalyst of Pd-coupled Ag and ZnO for the possible replacement of expensive Pt catalysts in DMFCs is successfully prepared. The as-made Pd@Ag/ZnO exhibits specific activity, which is 1.8-fold, 2.8-fold, and 4.6-fold higher than that of a Pd/ZnO catalyst, 20% Pd/C catalyst and Pd black, respectively. The improvement of the catalytic mechanism is likely due to the synergistic interaction between Pd@Ag and ZnO. The density functional theory (DFT) calculation results confirm that Ag doped into Pd weakens the adsorption of CO, dramatically improving the capability to resist CO poisoning.

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