This paper presents research on the use of multiple reconfigurable intelligent surfaces (RIS) in high-speed railway (HSR) tunnel communication systems for signal quality improvement and spectral efficiency (SE) maximi...
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In order to solve the problem of poor bicycle and pedestrian detection under sparse point cloud conditions in autonomous driving, an improved Voxel-RCNN algorithm is proposed to optimize the performance by introducing...
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Benefit to the advantages of easy deployment and high flexibility, unmanned aerial vehicle (UAV) has been utilized to act as the aerial base station, providing communications service for target areas, such as remote r...
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Autonomous underwater vehicles (AUVs) equipped with acoustic modems are currently one of the important means of obtaining underwater environment data such as sounds and images. They rely on high-speed underwater ...
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Autonomous underwater vehicles (AUVs) equipped with acoustic modems are currently one of the important means of obtaining underwater environment data such as sounds and images. They rely on high-speed underwater acoustic (UWA) communication technology for data transmission tasks. Orthogonal chirp division multiplexing (OCDM) is a multicarrier method based on chirp spread spectrum (CSS) which has better reliability in frequency selective fading channels than orthogonal frequency division multiplexing (OFDM). In this work, we combine index modulation (IM) and propose an OCDM-IM system that provides faster data rates when it activates the same number of subchirps as OCDM. On the other hand, it activates fewer subchirps when the data rate is the same, so it has better anti-interference capability. The simulation results under a measured UWA channel and random channels and the experimental results show that OCDM-IM has a better bit-error rate (BER) performance than that of OCDM and OFDM-IM systems when the subchirps are not fully loaded. In particular, when a small number of subchirps are activated, OCDM-IM is able to provide up to 2x bit rate with more than 5 dB improvement in BER performance. Our simulation and experimental results also show that IM has much better reliability than constellation mapping when Doppler effect is considered. Therefore, OCDM-IM is more suitable for the communication of AUVs. IEEE
Broadening spectral response range to realize the full spectrum photocatalysis is crucial to develop photocatalysts with satisfactory light-energy conversion ability.A full-spectrum driven p-n heterojunction photocata...
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Broadening spectral response range to realize the full spectrum photocatalysis is crucial to develop photocatalysts with satisfactory light-energy conversion ability.A full-spectrum driven p-n heterojunction photocatalytic system was rationally designed through introducing the Er^(3+)/Yb^(3+)co-doped BiOBr with up-conversion effect as the collector of near infrared light and photocatalysts ***,Cu_(3)Mo_(2)O_(9) with the photothermal effect as a heat source to accelerate the reaction at the surface through absorbing the near infrared *** photocatalytic activity of BiOBr:Yb^(3+),Er^(3+)/Cu3Mo2O9 composite was markedly strengthened under visible and near infrared light irradiation,and the BiOBr:Yb^(3+),Er^(3+)/Cu_(3)Mo_(2)O_(9)-5 composite displayed the optimal photodegradation activities for 0.03372 min^(-1) and 0.058 h^(-1),being 2.3-folds and 2.4-folds than that of pure BiOBr:Yb^(3+),Er^(3+)under the visible and near infrared light,*** position of doped ions(Yb^(3+)and Er^(3+))in BiOBr:Yb^(3+),Er^(3+)was determined from the X-ray absorption fine structure *** the reasonable mechanism of p-n heterojunction was proposed base on the results of experimental and density functional theory *** work provides a rational strategy for the design and development of full-spectrum heterojunction photocatalysts with the up-conversion and photothermal effects to increase the photocatalytic performance.
Aiming at the problems of high memory occupancy and too many inflection points and search points of A* algorithm in large-scale environment, an improved A* algorithm is proposed. Firstly, the adaptive adjustment of th...
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Biodiversity conservation in modern society is of paramount importance, given the decline in species globally. This research delves into the realm of species identification, an essential element for effective biodiver...
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Industrial safety helmets are crucial personal protec-tive gear but detecting them as small targets in complex environments is challenging. This work proposes enhancements to the YOLOv8 object detection frame-work, sp...
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With the rapid development of 6G wireless communication and edge computing in recent years, mobile devices and terminals have collected vast amounts of data to train Machine Learning (ML) models. Since communication a...
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