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33 results on '"Yang, Weixiang"'

2. Monocular BEV Perception of Road Scenes via Front-to-Top View Projection

Author

Liu, Wenxi, Li, Qi, Yang, Weixiang, Cai, Jiaxin, Yu, Yuanlong, Ma, Yuexin, He, Shengfeng, and Pan, Jia

Subjects
Computer Science - Computer Vision and Pattern Recognition
Abstract

HD map reconstruction is crucial for autonomous driving. LiDAR-based methods are limited due to expensive sensors and time-consuming computation. Camera-based methods usually need to perform road segmentation and view transformation separately, which often causes distortion and missing content. To push the limits of the technology, we present a novel framework that reconstructs a local map formed by road layout and vehicle occupancy in the bird's-eye view given a front-view monocular image only. We propose a front-to-top view projection (FTVP) module, which takes the constraint of cycle consistency between views into account and makes full use of their correlation to strengthen the view transformation and scene understanding. In addition, we also apply multi-scale FTVP modules to propagate the rich spatial information of low-level features to mitigate spatial deviation of the predicted object location. Experiments on public benchmarks show that our method achieves the state-of-the-art performance in the tasks of road layout estimation, vehicle occupancy estimation, and multi-class semantic estimation. For multi-class semantic estimation, in particular, our model outperforms all competitors by a large margin. Furthermore, our model runs at 25 FPS on a single GPU, which is efficient and applicable for real-time panorama HD map reconstruction., Comment: Extension to CVPR'21 paper "Projecting Your View Attentively: Monocular Road Scene Layout Estimation via Cross-View Transformation"

Published
2022

3. Ultra-high Resolution Image Segmentation via Locality-aware Context Fusion and Alternating Local Enhancement

Author

Liu, Wenxi, Li, Qi, Lin, Xindai, Yang, Weixiang, He, Shengfeng, and Yu, Yuanlong

Subjects
Computer Science - Computer Vision and Pattern Recognition
Abstract

Ultra-high resolution image segmentation has raised increasing interests in recent years due to its realistic applications. In this paper, we innovate the widely used high-resolution image segmentation pipeline, in which an ultra-high resolution image is partitioned into regular patches for local segmentation and then the local results are merged into a high-resolution semantic mask. In particular, we introduce a novel locality-aware context fusion based segmentation model to process local patches, where the relevance between local patch and its various contexts are jointly and complementarily utilized to handle the semantic regions with large variations. Additionally, we present the alternating local enhancement module that restricts the negative impact of redundant information introduced from the contexts, and thus is endowed with the ability of fixing the locality-aware features to produce refined results. Furthermore, in comprehensive experiments, we demonstrate that our model outperforms other state-of-the-art methods in public benchmarks. Our released codes are available at: https://github.com/liqiokkk/FCtL., Comment: Extension of ICCV 2021 "From Contexts to Locality: Ultra-high Resolution Image Segmentation via Locality-aware Contextual Correlation"

Published
2021

5. Monocular BEV Perception of Road Scenes via Front-to-Top View Projection

Author

Liu, Wenxi, Li, Qi, Yang, Weixiang, Cai, Jiaxin, Yu, Yuanlong, Ma, Yuexin, He, Shengfeng, and Pan, Jia

Abstract

HD map reconstruction is crucial for autonomous driving. LiDAR-based methods are limited due to expensive sensors and time-consuming computation. Camera-based methods usually need to perform road segmentation and view transformation separately, which often causes distortion and missing content. To push the limits of the technology, we present a novel framework that reconstructs a local map formed by road layout and vehicle occupancy in the bird’s-eye view given a front-view monocular image only. We propose a front-to-top view projection (FTVP) module, which takes the constraint of cycle consistency between views into account and makes full use of their correlation to strengthen the view transformation and scene understanding. In addition, we apply multi-scale FTVP modules to propagate the rich spatial information of low-level features to mitigate spatial deviation of the predicted object location. Experiments on public benchmarks show that our method achieves various tasks on road layout estimation, vehicle occupancy estimation, and multi-class semantic estimation, at a performance level comparable to the state-of-the-arts, while maintaining superior efficiency.

Published
2024
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11. Comparison of Different Approaches of Machine Learning Methods with Conventional Approaches on Container Throughput Forecasting.

Author

Xu, Shuojiang, Zou, Shidong, Huang, Junpeng, Yang, Weixiang, and Zeng, Fangli

Subjects
MACHINE learning, CONTAINERIZATION, TIME series analysis, SHIPPING containers, FORECASTING, CONTAINER terminals, COVID-19 pandemic, INTERNATIONAL trade
Abstract

Container transportation is an important mode of international trade logistics in the world today, and its changes will seriously affect the development of the international market. For example, the COVID-19 pandemic has added a huge drag to global container logistics. Therefore, the accurate forecasting of container throughput can make a significant contribution to stakeholders who want to develop more accurate operational strategies and reduce costs. However, the current research on port container throughput forecasting mainly focuses on proposing more innovative forecasting methods on a single time series, but lacks the comparison of the performance of different basic models in the same time series and different time series. This study uses nine methods to forecast the historical throughput of the world's top 20 container ports and compares the results within and between methods. The main findings of this study are as follows. First, GRU is a method that can produce more accurate results (0.54–2.27 MAPE and 7.62–112.48 RMSE) with higher probability (85% for MAPE and 75% for RMSE) when constructing container throughput forecasting models. Secondly, NM can be used for rapid and simple container throughput estimation when computing equipment and services are not available. Thirdly, the average accuracy of machine learning forecasting methods is higher than that of traditional methods, but the accuracy of individual machine learning forecasting methods may not be higher than that of the best conventional traditional methods. [ABSTRACT FROM AUTHOR]

Published
2022
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12. Efficient cycling utilization of solar-thermal energy for thermochromic displays with controllable heat output

Author

Yiyu Feng, Si Qianyu, Peng Long, Liqi Dong, Wei Feng, Yan Qinghai, Fu Linxia, and Yang Weixiang

Subjects
Thermochromism, Materials science, Renewable Energy, Sustainability and the Environment, business.industry, Heat output, 02 engineering and technology, General Chemistry, 021001 nanoscience & nanotechnology, Solar energy, Thermal energy storage, Power (physics), Optoelectronics, General Materials Science, 0210 nano-technology, business, Cycling, Energy (signal processing), Power density
Abstract

Use of solar energy as a source of heat is an important method of storing and providing clean energy for thermal management. However, the difficulties associated with combining the high-energy storage and high-rate heat release of solar thermal storage (STS) lower their ability to output heat controllably, and thus, prevent their application in temperature-sensitive or temperature-responsive systems. Herein, we report for the first time the closed-cycle utilization of photo-thermal energy for thermochromic displays by optimizing the solid-state high-rate heat output of STS films. By controlling the molecular interaction, a tri-azobenzene (Azo)-based templated assembly can be made to combine a maximum energy density of 150.3 W h kg−1, a long half-life (1250 h), and a high power density of 3036.9 W kg−1. The STS film can induce a reversible color change in a complicated thermochromic-patterned display by releasing heat to increase the temperature by 6–7 °C. We also realize variable heat release by controlling the heating rate and temperature to utilize photo-thermal energy efficiently. Efficient cycling utilization of photo-thermal energy using a tri-Azo assembly could be used to harness photo-thermal power for thermal management.

Published
2019

18. Controllable and Stable Deformation of a Self-Healing Photo-Responsive Supramolecular Assembly for an Optically Actuated Manipulator Arm

Author

Yan Qinghai, Wei Feng, Yiyu Feng, Liqi Dong, Fu Linxia, Peng Long, Si Qianyu, and Yang Weixiang

Subjects
chemistry.chemical_classification, Materials science, business.industry, Polyacrylic acid, 02 engineering and technology, Bending, Polymer, Deformation (meteorology), 010402 general chemistry, 021001 nanoscience & nanotechnology, 01 natural sciences, 0104 chemical sciences, Supramolecular assembly, Stress (mechanics), chemistry.chemical_compound, chemistry, Azobenzene, Self-healing, Optoelectronics, General Materials Science, 0210 nano-technology, business
Abstract

It is highly challenging to achieve an optically deformable polymer with good controllability, stability, and self-healability for fabricating an optically controlled microrobotics. Here, we present a photo-responsive self-healing supramolecular assembly cross-linked by 3,3',5,5'-azobenzenetetracarboxylic acid (t-Azo) enabling the controllable and stable deformation. The network (PAA-u) of polyacrylic acid (PAA) grafted with 2-ureido-4[1 H]-pyrimidinone (UPy) is formed via multiple intermolecular hydrogen bonds (H-bonds) between UPy and t-Azo moieties. Molecular H-bonds stabilize the cis-isomer, enables stress transfer at the interface, and also contributes to fast healability. The PAA-u/t-Azo assembly shows a green-light-induced bending deformation, which recovers its shape under the irradiation of UV light. On the basis of this controllable and reversible deformation, the PAA-u/t-Azo "hand" realizes reversible light-driven grabbing and releasing of an object by optimizing bending and recovery. The assembly also shows a fast and excellent self-healing performance irradiated by green light during deformation. The multiple-H-bonding-cross-linked assembly with stable deformation and fast self-healability can be used for the development of a multitude of advanced microrobotics.

Published
2018

22. Controlling Heat Release from a Close-Packed Bisazobenzene-Reduced-Graphene-Oxide Assembly Film for High-Energy Solid-State Photothermal Fuels

Author

Si Qianyu, Zhao Xiaoze, Chengqun Qin, Wei Feng, Yiyu Feng, and Yang Weixiang

Subjects
Models, Molecular, Steric effects, Hot Temperature, Materials science, General Chemical Engineering, Molecular Conformation, Oxide, Nanotechnology, 02 engineering and technology, 010402 general chemistry, 01 natural sciences, law.invention, Photochromism, chemistry.chemical_compound, Isomerism, law, Environmental Chemistry, General Materials Science, Graphite, business.industry, Graphene, Benzene, Oxides, Photothermal therapy, Photochemical Processes, 021001 nanoscience & nanotechnology, 0104 chemical sciences, Renewable energy, General Energy, chemistry, Intramolecular force, 0210 nano-technology, business, Azo Compounds
Abstract

A closed-cycle system for light-harvesting, storage, and heat release is important for utilizing and managing renewable energy. However, combining a high-energy, stable photochromic material with a controllable trigger for solid-state heat release remains a great challenge for developing photothermal fuels (PTFs). This paper presents a uniform PTF film fabricated by the assembly of close-packed bisazobenzene (bisAzo) grafted onto reduced graphene oxide (rGO). The assembled rGO-bisAzo template exhibited a high energy density of 131 Wh kg-1 and a long half-life of 37 days owing to inter- or intramolecular H-bonding and steric hindrance. The rGO-bisAzo PTF film released and accumulated heat to realize a maximum temperature difference (DT) of 15 °C and a DT of over 10 °C for 30 min when the temperature difference of the environment was greater than100 °C. Controlling heat release in the solid-state assembly paves the way to develop highly efficient and high-energy PTFs for a multitude of applications.

Published
2017

24. Nano‐Ferric Oxide Embedded in Graphene Oxide: High‐performance Electrocatalyst for Nitrogen Reduction at Ambient Condition.

Author

Wang, Fei, Xia, Lixue, Li, Xin, Yang, Weixiang, Zhao, Yan, and Mao, Jian

Subjects
GRAPHENE oxide, ELECTROCATALYSTS, NITROGEN reduction
Abstract

Nitrogen (N2) fixation at ambient condition by electrochemical N2 reduction reaction (NRR) is energy‐efficient and eco‐friendly as compared to the traditional Harber–Bosch process, but it is extremely challenging. Development and design of high‐performance NRR electrocatalysts are indispensable to achieve the goal. In this work, a strongly coupled hybrid of nano‐Fe3O4 with reduced graphene oxide (rGO) is synthesized via an in situ redox hydrothermal approach, and the synthesized Fe3O4@rGO hybrid has excellent activity, selectivity, and stability as an NRR catalyst. The NH3 yield rate of 28.01 μg h‐1 mg‐1 at −0.3 V and the Faradaic efficiency (FE) of 19.12% at −0.1 V are obtained in 0.1 M Na2SO4 solutions at ambient conditions. The superior NRR performance is attributed to the chemical coupling effect between rGO and nano‐Fe3O4 particles, which leads to the enhancement of the binding affinity to N2 molecules, improvement of the conductivity, and lowering the free energy of reaction for the limiting reaction step. This work provides a facile route in fabricating hybrid NRR catalysts with superior performance and shed lights on the reaction mechanism with theoretical mechanistic calculations. [ABSTRACT FROM AUTHOR]

Published
2021
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31. Census of Penguins on Ardley Island of Western Antarctic

Author

Zheng Guangmei, Yuan Junfeng, Zhang Zhengwang, and Yang Weixiang

Subjects
education.field_of_study, Eudyptes chrysolophus, Disturbance (geology), Ecology, biology, Population, Adelie penguin, Zoology, Census, biology.organism_classification, Pygoscelis, Geography, education, Ecology, Evolution, Behavior and Systematics, Nature and Landscape Conservation
Abstract

Four species of penguins were found on Ardley Island of King George Island during the austral summer of 1993 and 1994.Macaroni Penguin Eudyptes chrysolophus is a new record of bird on this Island·The numbers of nests found were 44 1 205 and 3678 for Chinstrap Penguin Pygoscelis antarctica,Adelie Penguin P.adeliae and Gentoo Penguin P. papua respectively. Totaly about 7430 fledged penguin chicks were produced on Ardley Island in the summer of 1 993 and 1 994. The decrease of the Island population of Chinstrap Penguins might have resulted from the increasing human disturbance.

Published
1994

32. A simulation study of carbon dioxide automotive air conditioning system

Author

Yang, Weixiang.

Subjects
Engineering, Mechanical
Abstract

The transcritical CO2 (R-744) automotive air conditioning system is a promising green solution to the currently used HFC-134a (R-134a) system and its considerable global warming impact. The advantages as well as the remaining challenges of the CO2 system have been deduced based on a comprehensive literature review. To optimize the CO2 air conditioning system and to increase its performance to the level of the conventional HFC-134a system, a comparison between CO2 and HFC-134a system performances was conducted in this simulation study. The simulation was performed on CO2 and HFC-134a automotive air conditioning systems as a comprehensive parametric study under practical system operating conditions. During the system operation, the characteristics of the transcritical CO2 refrigeration cycle were investigated in detail, and the beneficial thermophysical properties of CO2 refrigerant were identified. In addition, a detailed analysis based on the first and second laws of thermodynamic was applied to identify the thermodymanic losses of transcritical CO2 and conventional HFC-134a refrigeration systems. (Abstract shortened by UMI.) Source: Masters Abstracts International, Volume: 43-05, page: 1801. Advisers: Amir Fartaj; David S-K. Ting. Thesis (M.A.Sc.)--University of Windsor (Canada), 2004.

Published
2004

33. Effects of acid etching and adhesive treatments on host-derived cysteine cathepsin activity in dentin.

Author

Zhang W, Yang W, Wu S, Zheng K, Liao W, Chen B, Yao K, Liang G, and Li Y

Subjects
Cathepsins antagonists & inhibitors, Cathepsins drug effects, Chromogenic Compounds, Cysteine Proteases analysis, Cysteine Proteases drug effects, Cysteine Proteinase Inhibitors pharmacology, Dental Cements pharmacology, Dentin drug effects, Dentin-Bonding Agents pharmacology, Edetic Acid pharmacology, Fluorescent Dyes, Humans, Leucine analogs & derivatives, Leucine pharmacology, Phosphoric Acids pharmacology, Polymethacrylic Acids pharmacology, Resin Cements pharmacology, Acid Etching, Dental methods, Cathepsins analysis, Dental Bonding methods, Dentin enzymology
Abstract

Purpose: To analyze the effects of different processes during bonding on endogenous cysteine cathepsin activity in dentin., Materials and Methods: Dentin powder, prepared from extracted human third molars, was divided into 10 groups. Two lots of dentin powder were used to detect the effects of the procedure of protein extraction on endogenous cathepsin activity. The others were used to study effects of different acid-etching or adhesive treatments on enzyme activity. Concentrations of 37% phosphoric acid or 10% phosphoric acid, two etch-and-rinse adhesive systems, and two self-etching adhesive systems were used as dentin powder treatments. The untreated mineralized dentin powder was set as the control. After treatment, the proteins of each group were extracted. The total cathepsin activity in the extracts of each group was monitored with a fluorescence reader., Results: In the control group, there were no significant differences in cathepsin activity between the protein extract before EDTA treatment and the protein extract after EDTA treatment (p > 0.05). The cathepsin activities of the three different extracts in the 37% phosphoric acid-treated group were different from each other (p < 0.05). The two acid-etching groups and two etch-and-rinse groups showed significant enzyme activity reduction vs the control group (p < 0.05). There were no significant differences between those four groups (p > 0.05). Treating the dentin powder with any of the two self-etching adhesives resulted in an increase in cathepsin activity (p < 0.05)., Conclusions: The activity of cysteine cathepsins can be detected in dentin powder. Treatment with EDTA during protein extraction exerted an influence on cathepsin activity. Acid etching or etch-and-rinse adhesive systems may reduce the activity of endogenous cathepsins in dentin. Self-etching adhesive systems may increase the enzyme activity.

Published
2014
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