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  1. Article: Adaptive Fusion Based Method for Imbalanced Data Classification.

    Liang, Zefeng / Wang, Huan / Yang, Kaixiang / Shi, Yifan

    Frontiers in neurorobotics

    2022  Volume 16, Page(s) 827913

    Abstract: The imbalance problem is widespread in real-world applications. When training a classifier on the imbalance datasets, the classifier is hard to learn an appropriate decision boundary, which causes unsatisfying classification performance. To deal with the ...

    Abstract The imbalance problem is widespread in real-world applications. When training a classifier on the imbalance datasets, the classifier is hard to learn an appropriate decision boundary, which causes unsatisfying classification performance. To deal with the imbalance problem, various ensemble algorithms are proposed. However, conventional ensemble algorithms do not consider exploring an effective feature space to further improve the performance. In addition, they treat the base classifiers equally and ignore the different contributions of each base classifier to the ensemble result. In order to address these problems, we propose a novel ensemble algorithm that combines effective data transformation and an adaptive weighted voting scheme. First, we utilize modified metric learning to obtain an effective feature space based on imbalanced data. Next, the base classifiers are assigned different weights adaptively. The experiments on multiple imbalanced datasets, including images and biomedical datasets verify the superiority of our proposed ensemble algorithm.
    Language English
    Publishing date 2022-02-28
    Publishing country Switzerland
    Document type Journal Article
    ZDB-ID 2453002-5
    ISSN 1662-5218
    ISSN 1662-5218
    DOI 10.3389/fnbot.2022.827913
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  2. Book ; Online: PatchAD

    Zhong, Zhijie / Yu, Zhiwen / Yang, Yiyuan / Wang, Weizheng / Yang, Kaixiang

    Patch-based MLP-Mixer for Time Series Anomaly Detection

    2024  

    Abstract: Anomaly detection stands as a crucial aspect of time series analysis, aiming to identify abnormal events in time series samples. The central challenge of this task lies in effectively learning the representations of normal and abnormal patterns in a ... ...

    Abstract Anomaly detection stands as a crucial aspect of time series analysis, aiming to identify abnormal events in time series samples. The central challenge of this task lies in effectively learning the representations of normal and abnormal patterns in a label-lacking scenario. Previous research mostly relied on reconstruction-based approaches, restricting the representational abilities of the models. In addition, most of the current deep learning-based methods are not lightweight enough, which prompts us to design a more efficient framework for anomaly detection. In this study, we introduce PatchAD, a novel multi-scale patch-based MLP-Mixer architecture that leverages contrastive learning for representational extraction and anomaly detection. Specifically, PatchAD is composed of four distinct MLP Mixers, exclusively utilizing the MLP architecture for high efficiency and lightweight architecture. Additionally, we also innovatively crafted a dual project constraint module to mitigate potential model degradation. Comprehensive experiments demonstrate that PatchAD achieves state-of-the-art results across multiple real-world multivariate time series datasets. Our code is publicly available.\footnote{\url{https://github.com/EmorZz1G/PatchAD}}

    Comment: 13 pages, 16 figures, IJCAI 2024 under review, paper id 3166
    Keywords Computer Science - Machine Learning
    Subject code 006
    Publishing date 2024-01-18
    Publishing country us
    Document type Book ; Online
    Database BASE - Bielefeld Academic Search Engine (life sciences selection)

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  3. Book ; Online: STS-CCL

    Li, Lincan / Yang, Kaixiang / Luo, Fengji / Bi, Jichao

    Spatial-Temporal Synchronous Contextual Contrastive Learning for Urban Traffic Forecasting

    2023  

    Abstract: Efficiently capturing the complex spatiotemporal representations from large-scale unlabeled traffic data remains to be a challenging task. In considering of the dilemma, this work employs the advanced contrastive learning and proposes a novel Spatial- ... ...

    Abstract Efficiently capturing the complex spatiotemporal representations from large-scale unlabeled traffic data remains to be a challenging task. In considering of the dilemma, this work employs the advanced contrastive learning and proposes a novel Spatial-Temporal Synchronous Contextual Contrastive Learning (STS-CCL) model. First, we elaborate the basic and strong augmentation methods for spatiotemporal graph data, which not only perturb the data in terms of graph structure and temporal characteristics, but also employ a learning-based dynamic graph view generator for adaptive augmentation. Second, we introduce a Spatial-Temporal Synchronous Contrastive Module (STS-CM) to simultaneously capture the decent spatial-temporal dependencies and realize graph-level contrasting. To further discriminate node individuals in negative filtering, a Semantic Contextual Contrastive method is designed based on semantic features and spatial heterogeneity, achieving node-level contrastive learning along with negative filtering. Finally, we present a hard mutual-view contrastive training scheme and extend the classic contrastive loss to an integrated objective function, yielding better performance. Extensive experiments and evaluations demonstrate that building a predictor upon STS-CCL contrastive learning model gains superior performance than existing traffic forecasting benchmarks. The proposed STS-CCL is highly suitable for large datasets with only a few labeled data and other spatiotemporal tasks with data scarcity issue.

    Comment: This work was accepted by the 49th IEEE International Conference on Acoustics, Speech, & Signal Processing (ICASSP 2024). We will present our work in Seoul, Korea
    Keywords Computer Science - Machine Learning ; Computer Science - Artificial Intelligence
    Subject code 006 ; 004
    Publishing date 2023-07-04
    Publishing country us
    Document type Book ; Online
    Database BASE - Bielefeld Academic Search Engine (life sciences selection)

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  4. Book ; Online: Data-Centric Evolution in Autonomous Driving

    Li, Lincan / Shao, Wei / Dong, Wei / Tian, Yijun / Zhang, Qiming / Yang, Kaixiang / Zhang, Wenjie

    A Comprehensive Survey of Big Data System, Data Mining, and Closed-Loop Technologies

    2024  

    Abstract: The aspiration of the next generation's autonomous driving (AD) technology relies on the dedicated integration and interaction among intelligent perception, prediction, planning, and low-level control. There has been a huge bottleneck regarding the upper ...

    Abstract The aspiration of the next generation's autonomous driving (AD) technology relies on the dedicated integration and interaction among intelligent perception, prediction, planning, and low-level control. There has been a huge bottleneck regarding the upper bound of autonomous driving algorithm performance, a consensus from academia and industry believes that the key to surmount the bottleneck lies in data-centric autonomous driving technology. Recent advancement in AD simulation, closed-loop model training, and AD big data engine have gained some valuable experience. However, there is a lack of systematic knowledge and deep understanding regarding how to build efficient data-centric AD technology for AD algorithm self-evolution and better AD big data accumulation. To fill in the identified research gaps, this article will closely focus on reviewing the state-of-the-art data-driven autonomous driving technologies, with an emphasis on the comprehensive taxonomy of autonomous driving datasets characterized by milestone generations, key features, data acquisition settings, etc. Furthermore, we provide a systematic review of the existing benchmark closed-loop AD big data pipelines from the industrial frontier, including the procedure of closed-loop frameworks, key technologies, and empirical studies. Finally, the future directions, potential applications, limitations and concerns are discussed to arouse efforts from both academia and industry for promoting the further development of autonomous driving. The project repository is available at: https://github.com/LincanLi98/Awesome-Data-Centric-Autonomous-Driving.
    Keywords Computer Science - Robotics ; Computer Science - Computer Vision and Pattern Recognition
    Subject code 629
    Publishing date 2024-01-23
    Publishing country us
    Document type Book ; Online
    Database BASE - Bielefeld Academic Search Engine (life sciences selection)

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  5. Article: Reconstruction of Sentinel-2 Image Time Series Using Google Earth Engine

    Yang, Kaixiang / Luo, Youming / Li, Mengyao / Zhong, Shouyi / Liu, Qiang / Li, Xiuhong

    Remote Sensing. 2022 Sept. 04, v. 14, no. 17

    2022  

    Abstract: Sentinel-2 NDVI and surface reflectance time series have been widely used in various geoscience research, but the data is deteriorated or missing due to the cloud contamination, so it is necessary to reconstruct the Sentinel-2 NDVI and surface ... ...

    Abstract Sentinel-2 NDVI and surface reflectance time series have been widely used in various geoscience research, but the data is deteriorated or missing due to the cloud contamination, so it is necessary to reconstruct the Sentinel-2 NDVI and surface reflectance time series. At present, there are few studies on reconstructing the Sentinel-2 NDVI or surface reflectance time series, and these existing reconstruction methods have some shortcomings. We proposed a new method to reconstruct the Sentinel-2 NDVI and surface reflectance time series using the penalized least-square regression based on discrete cosine transform (DCT-PLS) method. This method iteratively identifies cloud-contaminated NDVI over NDVI time series from the Sentinel-2 surface reflectance data by adjusting the weights. The NDVI and surface reflectance time series are then reconstructed from cloud-free NDVI and surface reflectance using the adjusted weights as constraints. We have made some improvements to the DCT-PLS method. First, the traditional discrete cosine transformation (DCT) in the DCT-PLS method is matrix generated from discrete and equally spaced data, we reconfigured the DCT formulas to adapt for irregular interval time series, and optimized the control parameters N and s according to the typical vegetation samples in China. Second, the DCT-PLS method was deployed in the Google Earth Engine (GEE) platform for the efficiency and convenience of data users. We used the DCT-PLS method to reconstruct the Sentinel-2 NDVI time series and surface reflectance time series in the blue, green, red, and near infrared (NIR) bands in typical vegetation samples and the Zhangjiakou and Hangzhou study area. We found that this method performed better than the SG filter method in reconstructing the NDVI time series, and can identify and reconstruct the contaminated NDVI as well as surface reflectance with low root mean square error (RMSE) and high coefficient of determination (R²). However, in cases of a long range of cloud contamination, or above water surface, it may be necessary to increase the control parameter s for a more stable performance. The GEE code is freely available online and the link is in the conclusions of this article, researchers are welcome to use this method to generate cloudless Sentinel-2 NDVI and surface reflectance time series with 10 m spatial resolution, which is convenient for landcover classification and many other types of research.
    Keywords Internet ; land cover ; reflectance ; time series analysis ; vegetation ; China
    Language English
    Dates of publication 2022-0904
    Publishing place Multidisciplinary Digital Publishing Institute
    Document type Article
    ZDB-ID 2513863-7
    ISSN 2072-4292
    ISSN 2072-4292
    DOI 10.3390/rs14174395
    Database NAL-Catalogue (AGRICOLA)

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  6. Article: Extradural contralateral S1 nerve root transfer for spastic lower limb paralysis.

    Cao, Jiang / Chang, Jie / Wu, Chaoqin / Zhang, Sheng / Wang, Binyu / Yang, Kaixiang / Cao, Xiaojian / Sui, Tao

    Journal of biomedical research

    2023  Volume 37, Issue 5, Page(s) 394–400

    Abstract: The current study aims to ascertain the anatomical feasibility of transferring the contralateral S1 ventral root (VR) to the ipsilateral L5 VR for treating unilateral spastic lower limb paralysis. Six formalin-fixed (three males and three females) ... ...

    Abstract The current study aims to ascertain the anatomical feasibility of transferring the contralateral S1 ventral root (VR) to the ipsilateral L5 VR for treating unilateral spastic lower limb paralysis. Six formalin-fixed (three males and three females) cadavers were used. The VR of the contralateral S1 was transferred to the VR of the ipsilateral L5. The sural nerve was selected as a bridge between the donor and recipient nerve. The number of axons, the cross-sectional areas and the pertinent distances between the donor and recipient nerves were measured. The extradural S1 VR and L5 VR could be separated based on anatomical markers of the dorsal root ganglion. The gross distance between the S1 nerve root and L5 nerve root was 31.31 (± 3.23) mm in the six cadavers, while that on the diffusion tensor imaging was 47.51 (± 3.23) mm in 60 patients without spinal diseases, and both distances were seperately greater than that between the outlet of S1 from the spinal cord and the ganglion. The numbers of axons in the S1 VRs and L5 VRs were 13414.20 (± 2890.30) and 10613.20 (± 2135.58), respectively. The cross-sectional areas of the S1 VR and L5 VR were 1.68 (± 0.26) mm
    Language English
    Publishing date 2023-09-26
    Publishing country China
    Document type Journal Article
    ZDB-ID 2555537-6
    ISSN 1876-4819 ; 1674-8301
    ISSN (online) 1876-4819
    ISSN 1674-8301
    DOI 10.7555/JBR.37.20230068
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  7. Article ; Online: Thermal- and salt-activated shape memory hydrogels based on a gelatin/polyacrylamide double network.

    Chen, Fang / Yang, Kaixiang / Zhao, Dinglei / Yang, Haiyang

    RSC advances

    2019  Volume 9, Issue 32, Page(s) 18619–18626

    Abstract: Shape memory hydrogels have been extensively studied in the past decades owing to their exceptionally promising potential in a wide range of applications. Here, we present a gelatin/polyacrylamide double network hydrogel with thermal- and salt-activated ... ...

    Abstract Shape memory hydrogels have been extensively studied in the past decades owing to their exceptionally promising potential in a wide range of applications. Here, we present a gelatin/polyacrylamide double network hydrogel with thermal- and salt-activated shape memory effect. The thermally activated behavior is attributed to the reversible triple helix transformation of gelatin, and the salt-activated performance can be ascribed to the formation of hydrophobic interaction domains under the Hofmeister effect. The hydrogel can memorize a temporary shape successfully through soaking with (NH
    Language English
    Publishing date 2019-06-13
    Publishing country England
    Document type Journal Article
    ISSN 2046-2069
    ISSN (online) 2046-2069
    DOI 10.1039/c9ra02842k
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  8. Article: Downscaling Land Surface Temperature Based on Non-Linear Geographically Weighted Regressive Model over Urban Areas

    Wang, Shumin / Luo, Youming / Li, Xia / Yang, Kaixiang / Liu, Qiang / Luo, Xiaobo / Li, Xiuhong

    Remote Sensing. 2021 Apr. 19, v. 13, no. 8

    2021  

    Abstract: Land surface temperature (LST) is a vital physical parameter in geoscience research and plays a prominent role in surface and atmosphere interaction. Due to technical restrictions, the spatiotemporal resolution of satellite remote sensing LST data is ... ...

    Abstract Land surface temperature (LST) is a vital physical parameter in geoscience research and plays a prominent role in surface and atmosphere interaction. Due to technical restrictions, the spatiotemporal resolution of satellite remote sensing LST data is relatively low, which limits the potential applications of these data. An LST downscaling algorithm can effectively alleviate this problem and endow the LST data with more spatial details. Considering the spatial nonstationarity, downscaling algorithms have been gradually developed from least square models to geographical models. The current geographical LST downscaling models only consider the linear relationship between LST and auxiliary parameters, whereas non-linear relationships are neglected. Our study addressed this issue by proposing an LST downscaling algorithm based on a non-linear geographically weighted regressive (NL-GWR) model and selected the optimal combination of parameters to downscale the spatial resolution of a moderate resolution imaging spectroradiometer (MODIS) LST from 1000 m to 100 m. We selected Jinan city in north China and Wuhan city in south China from different seasons as study areas and used Landsat 8 images as reference data to verify the downscaling LST. The results indicated that the NL-GWR model performed well in all the study areas with lower root mean square error (RMSE) and mean absolute error (MAE), rather than the linear model.
    Keywords Landsat ; algorithms ; linear models ; surface temperature ; China
    Language English
    Dates of publication 2021-0419
    Publishing place Multidisciplinary Digital Publishing Institute
    Document type Article
    Note NAL-AP-2-clean
    ZDB-ID 2513863-7
    ISSN 2072-4292
    ISSN 2072-4292
    DOI 10.3390/rs13081580
    Database NAL-Catalogue (AGRICOLA)

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  9. Book ; Online: Few-shot learning with improved local representations via bias rectify module

    Dong, Chao / Ye, Qi / Meng, Wenchao / Yang, Kaixiang

    2021  

    Abstract: Recent approaches based on metric learning have achieved great progress in few-shot learning. However, most of them are limited to image-level representation manners, which fail to properly deal with the intra-class variations and spatial knowledge and ... ...

    Abstract Recent approaches based on metric learning have achieved great progress in few-shot learning. However, most of them are limited to image-level representation manners, which fail to properly deal with the intra-class variations and spatial knowledge and thus produce undesirable performance. In this paper we propose a Deep Bias Rectify Network (DBRN) to fully exploit the spatial information that exists in the structure of the feature representations. We first employ a bias rectify module to alleviate the adverse impact caused by the intra-class variations. bias rectify module is able to focus on the features that are more discriminative for classification by given different weights. To make full use of the training data, we design a prototype augment mechanism that can make the prototypes generated from the support set to be more representative. To validate the effectiveness of our method, we conducted extensive experiments on various popular few-shot classification benchmarks and our methods can outperform state-of-the-art methods.
    Keywords Computer Science - Computer Vision and Pattern Recognition
    Subject code 006
    Publishing date 2021-11-01
    Publishing country us
    Document type Book ; Online
    Database BASE - Bielefeld Academic Search Engine (life sciences selection)

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  10. Article: Thermal- and salt-activated shape memory hydrogels based on a gelatin/polyacrylamide double network

    Chen, Fang / Yang, Kaixiang / Zhao, Dinglei / Yang, Haiyang

    RSC advances. 2019 June 13, v. 9, no. 32

    2019  

    Abstract: Shape memory hydrogels have been extensively studied in the past decades owing to their exceptionally promising potential in a wide range of applications. Here, we present a gelatin/polyacrylamide double network hydrogel with thermal- and salt-activated ... ...

    Abstract Shape memory hydrogels have been extensively studied in the past decades owing to their exceptionally promising potential in a wide range of applications. Here, we present a gelatin/polyacrylamide double network hydrogel with thermal- and salt-activated shape memory effect. The thermally activated behavior is attributed to the reversible triple helix transformation of gelatin, and the salt-activated performance can be ascribed to the formation of hydrophobic interaction domains under the Hofmeister effect. The hydrogel can memorize a temporary shape successfully through soaking with (NH4)2SO4 solution or decreasing temperature, and recovers its permanent shape by extracting ions with deionized water or increasing temperature. In particular, the hydrogel exhibits excellent shape fixity and recovery ratio. The presented strategy may enrich the construction as well as application of biopolymer based shape memory hydrogels.
    Keywords ammonium sulfate ; biopolymers ; gelatin ; hydrogels ; hydrophobic bonding ; ions ; polyacrylamide ; soaking ; temperature
    Language English
    Dates of publication 2019-0613
    Size p. 18619-18626.
    Publishing place The Royal Society of Chemistry
    Document type Article
    ISSN 2046-2069
    DOI 10.1039/c9ra02842k
    Database NAL-Catalogue (AGRICOLA)

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