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  1. Article ; Online: A Novel Tensor Ring Sparsity Measurement for Image Completion.

    Zeng, Junhua / Qiu, Yuning / Ma, Yumeng / Wang, Andong / Zhao, Qibin

    Entropy (Basel, Switzerland)

    2024  Volume 26, Issue 2

    Abstract: As a promising data analysis technique, sparse modeling has gained widespread traction in the field of image processing, particularly for image recovery. The matrix rank, served as a measure of data sparsity, quantifies the sparsity within the Kronecker ... ...

    Abstract As a promising data analysis technique, sparse modeling has gained widespread traction in the field of image processing, particularly for image recovery. The matrix rank, served as a measure of data sparsity, quantifies the sparsity within the Kronecker basis representation of a given piece of data in the matrix format. Nevertheless, in practical scenarios, much of the data are intrinsically multi-dimensional, and thus, using a matrix format for data representation will inevitably yield sub-optimal outcomes. Tensor decomposition (TD), as a high-order generalization of matrix decomposition, has been widely used to analyze multi-dimensional data. In a direct generalization to the matrix rank, low-rank tensor modeling has been developed for multi-dimensional data analysis and achieved great success. Despite its efficacy, the connection between TD rank and the sparsity of the tensor data is not direct. In this work, we introduce a novel tensor ring sparsity measurement (TRSM) for measuring the sparsity of the tensor. This metric relies on the tensor ring (TR) Kronecker basis representation of the tensor, providing a unified interpretation akin to matrix sparsity measurements, wherein the Kronecker basis serves as the foundational representation component. Moreover, TRSM can be efficiently computed by the product of the ranks of the mode-2 unfolded TR-cores. To enhance the practical performance of TRSM, the folded-concave penalty of the minimax concave penalty is introduced as a nonconvex relaxation. Lastly, we extend the TRSM to the tensor completion problem and use the alternating direction method of the multipliers scheme to solve it. Experiments on image and video data completion demonstrate the effectiveness of the proposed method.
    Language English
    Publishing date 2024-01-24
    Publishing country Switzerland
    Document type Journal Article
    ZDB-ID 2014734-X
    ISSN 1099-4300 ; 1099-4300
    ISSN (online) 1099-4300
    ISSN 1099-4300
    DOI 10.3390/e26020105
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  2. Article ; Online: Balanced Unfolding Induced Tensor Nuclear Norms for High-Order Tensor Completion.

    Qiu, Yuning / Zhou, Guoxu / Wang, Andong / Zhao, Qibin / Xie, Shengli

    IEEE transactions on neural networks and learning systems

    2024  Volume PP

    Abstract: The recently proposed tensor tubal rank has been witnessed to obtain extraordinary success in real-world tensor data completion. However, existing works usually fix the transform orientation along the third mode and may fail to turn multidimensional low- ... ...

    Abstract The recently proposed tensor tubal rank has been witnessed to obtain extraordinary success in real-world tensor data completion. However, existing works usually fix the transform orientation along the third mode and may fail to turn multidimensional low-tubal-rank structure into account. To alleviate these bottlenecks, we introduce two unfolding induced tensor nuclear norms (TNNs) for the tensor completion (TC) problem, which naturally extends tensor tubal rank to high-order data. Specifically, we show how multidimensional low-tubal-rank structure can be captured by utilizing a novel balanced unfolding strategy, upon which two TNNs, namely, overlapped TNN (OTNN) and latent TNN (LTNN), are developed. We also show the immediate relationship between the tubal rank of unfolding tensor and the existing tensor network (TN) rank, e.g., CANDECOMP/PARAFAC (CP) rank, Tucker rank, and tensor ring (TR) rank, to demonstrate its efficiency and practicality. Two efficient TC models are then proposed with theoretical guarantees by analyzing a unified nonasymptotic upper bound. To solve optimization problems, we develop two alternating direction methods of multipliers (ADMM) based algorithms. The proposed models have been demonstrated to exhibit superior performance based on experimental findings involving synthetic and real-world tensors, including facial images, light field images, and video sequences.
    Language English
    Publishing date 2024-04-24
    Publishing country United States
    Document type Journal Article
    ISSN 2162-2388
    ISSN (online) 2162-2388
    DOI 10.1109/TNNLS.2024.3373384
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  3. Article ; Online: Chemical exfoliating of boron nitride into edge-hydroxylated nanosheets

    Chen, Caifeng / Shao, Chenkang / Wang, Andong

    J Mater Sci. 2023 Mar., v. 58, no. 10, p. 4416-4427

    2023  , Page(s) 4416–4427

    Abstract: The edge-hydroxylated boron nitride nanosheets (BNNS) not only has excellent thermal stability, electrical properties, but also has high specific surface area, good dispersibility and compatibility. In this paper, edge-hydroxylated BNNS was obtained by ... ...

    Abstract The edge-hydroxylated boron nitride nanosheets (BNNS) not only has excellent thermal stability, electrical properties, but also has high specific surface area, good dispersibility and compatibility. In this paper, edge-hydroxylated BNNS was obtained by stripping hexagonal boron nitride (h-BN) using wet chemical reaction method. The hydroxylated structure of the surface and formation mechanism of BNNS were analyzed, and the optimal controlled conditions were explored by orthogonal test. The results showed that the content of N element in the center of the BNNS (46.44 at. %) is significantly higher than that of B element in the edge of the sheets (33.10 at. %), and the content of O element in the edge of the sheets is nearly 30% higher than that in the center. It indicates that the edge of the BNNS introduces more oxygen than h-BN, the nitrogen atoms at the edge are replaced by oxygen atoms to achieve hydroxylation. When the mass ratio of h-BN and potassium permanganate is 1 g: 5 g, the reaction time is 9 h, and the reaction temperature is 60 °C, the obtained nanosheets have the best hydroxylation and good stripping effect. The average lateral size of the exfoliated nanosheets is 123 nm and only about three layers.
    Keywords boron nitride ; dispersibility ; hydroxylation ; nanosheets ; nitrogen ; oxygen ; potassium permanganate ; surface area ; temperature ; thermal stability
    Language English
    Dates of publication 2023-03
    Size p. 4416-4427
    Publishing place Springer US
    Document type Article ; Online
    ZDB-ID 2015305-3
    ISSN 1573-4803 ; 0022-2461
    ISSN (online) 1573-4803
    ISSN 0022-2461
    DOI 10.1007/s10853-023-08316-7
    Database NAL-Catalogue (AGRICOLA)

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  4. Article ; Online: Generation and free-space transmission characterization of bottle vortex beam.

    Yang, Jiaxiong / Hu, Wuli / Wang, Andong / Zhu, Long

    Optics express

    2023  Volume 31, Issue 25, Page(s) 41094–41104

    Abstract: Vortex beams carrying orbital angular momentum (OAM) with the doughnut-shaped intensity distribution can be employed in free-space optical (FSO) communication links to circumvent obstructions. However, the size of the receiver aperture is proportional to ...

    Abstract Vortex beams carrying orbital angular momentum (OAM) with the doughnut-shaped intensity distribution can be employed in free-space optical (FSO) communication links to circumvent obstructions. However, the size of the receiver aperture is proportional to the size of obstructions, which seriously constrains the application of OAM beams in this scenario. In this paper, we propose a method to generate bottle vortex beams (BVBs) with a parabolic trajectory by manipulating the radial phase distribution of conventional OAM beams. Meanwhile, the trajectory of BVBs generated are highly compatible with the predesigned trajectory by using this method. Moreover, we evaluate the free-space transmission performance of BVBs under atmospheric turbulence and limited receiving aperture. The results show that BVBs have better OAM FSO communication link performance compared with conventional OAM beams and Bessel beams. In addition, the performance of the BVBs circumventing obstructions is further investigated. The simulation results show that when setting the atmospheric turbulence strength D/r
    Language English
    Publishing date 2023-12-12
    Publishing country United States
    Document type Journal Article
    ZDB-ID 1491859-6
    ISSN 1094-4087 ; 1094-4087
    ISSN (online) 1094-4087
    ISSN 1094-4087
    DOI 10.1364/OE.506098
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  5. Article ; Online: Predicting the orbital angular momentum of atmospheric turbulence for OAM-based free-space optical communication.

    Hu, Wuli / Yang, Jiaxiong / Zhu, Long / Wang, Andong

    Optics express

    2023  Volume 31, Issue 25, Page(s) 41060–41071

    Abstract: Spatial modes of light are susceptible to distortion, particularly by the presence of turbulence in atmospheric free-space links. The scattering of one mode to another disrupts the orthogonality among distinct orbital angular momentum (OAM) modes, ... ...

    Abstract Spatial modes of light are susceptible to distortion, particularly by the presence of turbulence in atmospheric free-space links. The scattering of one mode to another disrupts the orthogonality among distinct orbital angular momentum (OAM) modes, leading to modal crosstalk between multiple channels. To enhance the performance of OAM-multiplexed free-space optical (FSO) communication, a convolutional neural network (CNN)-based turbulent OAM approach is proposed for compensating turbulence, with a specific focus on predicting the OAM of turbulence itself. An operator approach is utilized to extract the OAM component of atmospheric turbulence and the CNN is trained to predict the turbulent OAM coefficients. By employing the proposed network, the received power of the OAM-based FSO link can be improved by more than 10 dB under weak to strong turbulence conditions. Compared to Zernike modes, the turbulent OAM modes characterize most of the turbulence information using only a small number of orders. After compensation, when the strong turbulence strength D/r0 = 4, the received power of the transmitted beams with turbulent OAM improves by 4 dB over that with Zernike. Additionally, the crosstalk of multiplexed channels with turbulent OAM is reduced by 10 dB over that with Zernike under varying turbulence conditions.
    Language English
    Publishing date 2023-12-12
    Publishing country United States
    Document type Journal Article
    ZDB-ID 1491859-6
    ISSN 1094-4087 ; 1094-4087
    ISSN (online) 1094-4087
    ISSN 1094-4087
    DOI 10.1364/OE.504713
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  6. Article ; Online: Direct prediction and compensation of atmospheric turbulence for free-space integer and fractional order OAM multiplexed transmission links.

    Wu, Yuhang / Wang, Andong / Zhu, Long

    Optics express

    2023  Volume 31, Issue 22, Page(s) 36078–36095

    Abstract: Atmospheric turbulence has an adverse impact on orbital angular momentum (OAM) beam transmission, resulting in power fluctuations and mode crosstalk. These challenges are particularly pronounced in OAM multiplexing links. In this paper, we propose and ... ...

    Abstract Atmospheric turbulence has an adverse impact on orbital angular momentum (OAM) beam transmission, resulting in power fluctuations and mode crosstalk. These challenges are particularly pronounced in OAM multiplexing links. In this paper, we propose and demonstrate a novel network architecture that integrates convolutional layers and residual structures to address the issue of turbulence phase compensation. By harnessing the local feature learning capability of convolutional layers and the information-preserving function of residual structures, we aim to mitigate the adverse effects of network depth on information loss. By employing the proposed network, we compensate the turbulence phase directly using the received intensity distributions for free space multiplexed integer and fractional order OAM links, respectively. The obtained results show that the received optical power can be improved for more than 10 dB for integer order OAM multiplexed FSO links under weak to strong turbulence conditions, while 9 dB for fractional-order OAM multiplexed FSO links. Moreover, mode crosstalk can be reduced for about 10 dB under 4 OAM modes multiplexed links under turbulence strength D/r0=5. The proposed deep learning based atmospheric turbulence compensation method can predict phase screens rapidly and accurately, thus enhancing the dependability of future OAM multiplexing technology.
    Language English
    Publishing date 2023-11-28
    Publishing country United States
    Document type Journal Article
    ZDB-ID 1491859-6
    ISSN 1094-4087 ; 1094-4087
    ISSN (online) 1094-4087
    ISSN 1094-4087
    DOI 10.1364/OE.501510
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  7. Book ; Online: Exploring Concept Contribution Spatially

    Wang, Andong / Lee, Wei-Ning

    Hidden Layer Interpretation with Spatial Activation Concept Vector

    2022  

    Abstract: To interpret deep learning models, one mainstream is to explore the learned concepts by networks. Testing with Concept Activation Vector (TCAV) presents a powerful tool to quantify the contribution of query concepts (represented by user-defined guidance ... ...

    Abstract To interpret deep learning models, one mainstream is to explore the learned concepts by networks. Testing with Concept Activation Vector (TCAV) presents a powerful tool to quantify the contribution of query concepts (represented by user-defined guidance images) to a target class. For example, we can quantitatively evaluate whether and to what extent concept striped contributes to model prediction zebra with TCAV. Therefore, TCAV whitens the reasoning process of deep networks. And it has been applied to solve practical problems such as diagnosis. However, for some images where the target object only occupies a small fraction of the region, TCAV evaluation may be interfered with by redundant background features because TCAV calculates concept contribution to a target class based on a whole hidden layer. To tackle this problem, based on TCAV, we propose Spatial Activation Concept Vector (SACV) which identifies the relevant spatial locations to the query concept while evaluating their contributions to the model prediction of the target class. Experiment shows that SACV generates a more fine-grained explanation map for a hidden layer and quantifies concepts' contributions spatially. Moreover, it avoids interference from background features. The code is available on https://github.com/AntonotnaWang/Spatial-Activation-Concept-Vector.

    Comment: Accepted by CVPR 2022 Workshop XAI4CV
    Keywords Computer Science - Computer Vision and Pattern Recognition
    Subject code 004
    Publishing date 2022-05-21
    Publishing country us
    Document type Book ; Online
    Database BASE - Bielefeld Academic Search Engine (life sciences selection)

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  8. Article ; Online: Turbulence-resistant high-capacity free-space optical communications using OAM mode group multiplexing.

    Zhu, Long / Deng, Mingliang / Lu, Bing / Guo, Xiaojin / Wang, Andong

    Optics express

    2023  Volume 31, Issue 9, Page(s) 14454–14463

    Abstract: Twisted light carrying orbital angular momentum (OAM), which features a helical phase front, has shown its potential applications in diverse areas, especially in free-space optical (FSO) communications. Multiple orthogonal OAM beams can be utilized to ... ...

    Abstract Twisted light carrying orbital angular momentum (OAM), which features a helical phase front, has shown its potential applications in diverse areas, especially in free-space optical (FSO) communications. Multiple orthogonal OAM beams can be utilized to enable high-capacity FSO communication systems. However, for practical OAM-based FSO communication links, atmospheric turbulence will cause serious power fluctuations and inter-model crosstalk between the multiplexed OAM channels, impairing link performance. In this paper, we propose and experimentally demonstrate a novel OAM mode-group multiplexing (OAM-MGM) scheme with transmitter mode diversity to increase system reliability under turbulence. Without adding extra system complexity, an FSO system transmitting two OAM groups with a total of 144 Gbit/s discrete multi-tone (DMT) signal is demonstrated under turbulence strength D/r0 of 1, 2, and 4. In our experiments, the proposed OAM-MGM scheme helps to achieve bit-error-rate (BER) mostly less than 3.8 × 10
    Language English
    Publishing date 2023-05-08
    Publishing country United States
    Document type Journal Article
    ZDB-ID 1491859-6
    ISSN 1094-4087 ; 1094-4087
    ISSN (online) 1094-4087
    ISSN 1094-4087
    DOI 10.1364/OE.488053
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  9. Article ; Online: An ensemble learning simplification approach based on multiple machine-learning algorithms with the fusion using of raster and vector data and a use case of coastline simplification

    DU Jiawei / WU Fang / ZHU Li / LIU Chengyi / WANG Andong

    Acta Geodaetica et Cartographica Sinica, Vol 51, Iss 3, Pp 373-

    2022  Volume 387

    Abstract: To make use of accumulated simplification data and their contained simplification knowledge sufficiently, we propose an intelligent method based on the integration of several machine learning algorithms, which can use vector features and raster images to ...

    Abstract To make use of accumulated simplification data and their contained simplification knowledge sufficiently, we propose an intelligent method based on the integration of several machine learning algorithms, which can use vector features and raster images to learn the vertex selection of polyline simplification in this paper. First, vertex selection models based on vector features and raster images are constructed by the fully connected neural network and the convolutional neural network respectively. Trained by corresponding samples, these two models can be utilized to generate vertex selection decisions via inputting vector features or raster images respectively. Second, some fusion models are constructed based on the linear weighting method, naive Bayes method, support vector machine, and artificial neural network to utilize outputs of vector-based and raster-based models to generate better decisions for vertex simplification. Finally, the proposed method applies into a use case. Experimental results show that the vector-based model and the raster-based model can learn and master vertex simplification in different levels, and fusion models can make complementary advantages of raster-based and vector-based models to improve the simplification accuracy further, and the best fusion model is better than some other simplification methods.
    Keywords map generalization ; simplification ; machine learning ; artificial neural network ; Mathematical geography. Cartography ; GA1-1776
    Subject code 006
    Language Chinese
    Publishing date 2022-03-01T00:00:00Z
    Publisher Surveying and Mapping Press
    Document type Article ; Online
    Database BASE - Bielefeld Academic Search Engine (life sciences selection)

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  10. Article ; Online: Internal structuring of gallium arsenide using short laser pulses.

    Das, Amlan / Wang, Andong / Utéza, Olivier / Grojo, David

    Optics express

    2022  Volume 30, Issue 21, Page(s) 39101–39110

    Abstract: Laser writing inside semiconductors attracts attention as a possible route for three-dimensional integration in advanced micro technologies. In this context, gallium arsenide (GaAs) is a material for which the best conditions for laser internal ... ...

    Abstract Laser writing inside semiconductors attracts attention as a possible route for three-dimensional integration in advanced micro technologies. In this context, gallium arsenide (GaAs) is a material for which the best conditions for laser internal modification (LIM) have not been established yet. We address this question by using laser pulses at a fixed wavelength of 1550-nm. A large parameter space is investigated including the response to the applied pulse energy, pulse duration (from femtosecond to nanosecond) and the focusing conditions. We report that well-defined and reproducible internal modifications are achievable with tightly focused nanosecond pulses. The measured writing thresholds are systematically compared to those obtained in silicon (Si), a more extensively studied material. In comparison to Si, we also observe that GaAs is more prone to filamentation effects affecting the modification responses. The reported specific observations for LIM of GaAs should facilitate the future process developments for applications in electronics or photonics.
    Language English
    Publishing date 2022-10-18
    Publishing country United States
    Document type Journal Article
    ZDB-ID 1491859-6
    ISSN 1094-4087 ; 1094-4087
    ISSN (online) 1094-4087
    ISSN 1094-4087
    DOI 10.1364/OE.471432
    Database MEDical Literature Analysis and Retrieval System OnLINE

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