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Survey of deep learning based EEG data analysis technology
Bo ZHONG,Pengfei WANG,Yiqiao WANG,Xiaoling WANG
Journal of ZheJiang University (Engineering Science)    2024, 58 (5): 879-890.   DOI: 10.3785/j.issn.1008-973X.2024.05.001
Abstract   HTML PDF (690KB) ( 13198 )  

A thorough analysis and cross-comparison of recent relevant works was provided, outlining a closed-loop process for EEG data analysis based on deep learning. EEG data were introduced, and the application of deep learning in three key stages: preprocessing, feature extraction, and model generalization was unfolded. The research ideas and solutions provided by deep learning algorithms in the respective stages were delineated, including the challenges and issues encountered at each stage. The main contributions and limitations of different algorithms were comprehensively summarized. The challenges faced and future directions of deep learning technology in handling EEG data at each stage were discussed.

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Multimodal sentiment analysis model based on multi-task learning and stacked cross-modal Transformer
Qiao-hong CHEN,Jia-jin SUN,Yang-bo LOU,Zhi-jian FANG
Journal of ZheJiang University (Engineering Science)    2023, 57 (12): 2421-2429.   DOI: 10.3785/j.issn.1008-973X.2023.12.009
Abstract   HTML PDF (1171KB) ( 4146 )  

A new multimodal sentiment analysis model (MTSA) was proposed on the basis of cross-modal Transformer, aiming at the difficult retention of the modal feature heterogeneity for single-modal feature extraction and feature redundancy for cross-modal feature fusion. Long short-term memory (LSTM) and multi-task learning framework were used to extract single-modal contextual semantic information, the noise was removed and the modal feature heterogeneity was preserved by adding up auxiliary modal task losses. Multi-tasking gating mechanism was used to adjust cross-modal feature fusion. Text, audio and visual modal features were fused in a stacked cross-modal Transformer structure to improve fusion depth and avoid feature redundancy. MTSA was evaluated in the MOSEI and SIMS data sets, results show that compared with other advanced models, MTSA has better overall performance, the accuracy of binary classification reached 83.51% and 84.18% respectively.

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Multi-behavior aware service recommendation based on hypergraph graph convolution neural network
Jia-wei LU,Duan-ni LI,Ce-ce WANG,Jun XU,Gang XIAO
Journal of ZheJiang University (Engineering Science)    2023, 57 (10): 1977-1986.   DOI: 10.3785/j.issn.1008-973X.2023.10.007
Abstract   HTML PDF (1380KB) ( 2471 )  

A multi-behavior aware service recommendation method based on hypergraph graph convolutional neural network (MBSRHGNN) was proposed to resolve the problem of insufficient high-order service feature extraction in existing service recommendation methods. A multi-hypergraph was constructed according to user-service interaction types and service mashups. A dual-channel hypergraph convolutional network was designed based on the spectral decomposition theory with functional and structural properties of multi-hypergraph. Chebyshev polynomial was used to approximate hypergraph convolution kernel to reduce computational complexity. Self-attention mechanism and multi-behavior recommendation methods were combined to measure the importance difference between multi-behavior interactions during the hypergraph convolution process. A hypergraph pooling method named HG-DiffPool was proposed to reduce the feature dimensionality. The probability distribution for recommending different services was learned by integrating service embedding vector and hypergraph signals. Real service data was obtained by the crawler and used to construct datasets with different sparsity for experiments. Experimental results showed that the MBSRHGNN method could adapt to recommendation scenario with highly sparse data, and was superior to the existing baseline methods in accuracy and relevance.

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Structural design and experimental analysis of new UHPC-NC composite bent cap
Cijun LIU,Lifeng LI,Xudong SHAO,Tao CHEN,Guanhua ZHANG,Jiawei WANG,Huazhen YANG,Yalong ZHAO
Journal of ZheJiang University (Engineering Science)    2024, 58 (11): 2355-2363.   DOI: 10.3785/j.issn.1008-973X.2024.11.017
Abstract   HTML PDF (2785KB) ( 2190 )  

A new composite bent cap consisting of a shell made of steel plate and ultra-high-performance concrete (UHPC) and cast-in-place core normal concrete (NC) was proposed in order to realize the assembly and rapid construction of ultra-large-scale bent cap for urban viaducts or highway reconstruction and expansion projects. Parametric analysis of different UHPC and steel plate thickness was conducted in order to analyze the influence of the thickness of UHPC and steel mold plate on its stress performance. Results showed that the stiffness of the shell was affected by the thickness of UHPC and steel plate and their ratio together under the action of self-weight. The thicker the UHPC and steel plate are, the better the stress performance of the shell is, but the economy will be reduced when tensioning prestress and casting concrete. It is recommended to use UHPC thickness of 70 mm and steel plate thickness of 6 mm. A piece of 1∶2.5 scaled-down model was designed and static loading test was conducted in order to verify the feasibility and safety of this scheme. Results show that the new UHPC-NC composite bent cap has good force performance and high safety reserve, which can provide reference for the assembly construction of bent cap.

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Spatial-temporal multi-graph convolution for traffic flow prediction by integrating knowledge graphs
Jinye LI,Yongqiang LI
Journal of ZheJiang University (Engineering Science)    2024, 58 (7): 1366-1376.   DOI: 10.3785/j.issn.1008-973X.2024.07.006
Abstract   HTML PDF (1616KB) ( 2113 )  

A spatial-temporal multi-graph convolution traffic flow prediction model by integrating static and dynamic knowledge graphs was proposed, as current traffic flow prediction methods focus on the spatial-temporal correlation of traffic information and fail to fully take into account the influence of external factors on traffic. An urban traffic knowledge graph and four road network topological graphs with distinct semantics were systematically constructed, drawing upon the road traffic information and the external factors. The urban traffic knowledge graph was inputted into the relational evolution graph convolutional neural network to realize the knowledge embedding. The traffic flow matrix and the knowledge embedding were integrated using the knowledge fusion module. The four road network topology graphs and the traffic flow matrix with fused knowledge were fed into the spatial-temporal multi-graph convolution module to extract spatiotemporal features, and the traffic flow prediction value was outputted through the fully connected layer. The model performance was evaluated on a Hangzhou traffic data set. Compared with the advanced baseline, the performance of the proposed model improved by 5.76%-10.71%. Robustness experiment results show that the proposed model has a strong ability to resist interference.

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Research overview on touchdown detection methods for footed robots
Xiaoyong JIANG,Kaijian YING,Qiwei WU,Xuan WEI
Journal of ZheJiang University (Engineering Science)    2024, 58 (2): 334-348.   DOI: 10.3785/j.issn.1008-973X.2024.02.012
Abstract   HTML PDF (1751KB) ( 1860 )  

The effects of leg structure design, foot-end design and sensor design on touchdown detection were comprehensively discussed by analyzing the existing legged robot touchdown detection methods. The touchdown method for direct detection of external sensors, the touchdown detection method based on kinematics and dynamics, and the touchdown detection method based on learning were summarized. Touchdown detection methods were summarized in three special scenarios: slippery ground, soft ground, and non-foot-end contact. The application scenarios of touchdown detection technology were analyzed, including the three application scenarios of motion control requirements, navigation applications, and terrain and geological sensing. The development trends were pointed out, which related to the four major touchdown detection methods of hardware improvement and integration, multi-mode touchdown detection, multi-sensor fusion touchdown detection, and intelligent touchdown detection. The specific relationships between various touchdown detection algorithms were summarized, which provided guidance for the development of follow-up technology for touchdown detection and specific applications of touchdown detection.

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Dynamic 3D reconstruction method using binocular vision and improved YOLOv8
Jingyao HE,Pengfei LI,Chengzhi WANG,Zhenming LV,Ping MU
Journal of ZheJiang University (Engineering Science)    2025, 59 (7): 1443-1450.   DOI: 10.3785/j.issn.1008-973X.2025.07.012
Abstract   HTML PDF (7266KB) ( 1713 )  

A dynamic 3D reconstruction technology for construction sites was proposed to ensure safety and efficiency in the construction process. A Binocular camera was deployed to scan the reconstruction site in 3D to obtain the model base and target activity trajectory. The YOLOv8 model was enhanced with an attentional scale sequence fusion (ASF) module to form the YOLOv8-ASF framework, which improved the accuracy and performance of the model, to solve the pain points such as target occlusion and target loss. The improved semi-global block matching (SGBM) algorithm was fused, and the YOLOv8-ASF-SGBM algorithm was integrated with the YOLOv8-ASF to achieve near-real-time target recognition and localization based on 2D images. The obtained depth information was used to 3D project the behavior trajectories of dynamic elements into the substrate, to realize the near-real-time and full-view monitoring of the real construction site. Experimental results show that the proposed technology reproduces the movement trajectory of construction dynamic elements in high-precision three-dimensional, and the relative error with the real motion trajectory of dynamic elements is less than 5%, which can realize high-precision full-view three-dimensional monitoring based on two-dimensional image and video information, and has good application scenarios and engineering value.

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Fact-based similar case retrieval methods based on statutory knowledge
Linrui LI,Dongsheng WANG,Hongjie FAN
Journal of ZheJiang University (Engineering Science)    2024, 58 (7): 1357-1365.   DOI: 10.3785/j.issn.1008-973X.2024.07.005
Abstract   HTML PDF (814KB) ( 1677 )  

Existing research on the retrieval task of similar cases ignores the legal logic that the model should imply, and cannot adapt to the requirements of case similarity criteria in practical applications. Few datasets in Chinese for case retrieval tasks are difficult to meet the research needs. A similar case retrieval model was proposed based on legal logic and strong interpretability, and a case event logic graph was constructed based on predicate verbs. The statutory knowledge corresponding to various crimes was integrated into the proposed model, and the extracted elements were input to a neural network-based scorer to realize the task of case retrieval accurately and efficiently. A Confusing-LeCaRD dataset was built for the case retrieval task with a confusing group of charges as the main retrieval causes. Experiments show that the normalized discounted cumulative gain of the proposed model on the LeCaRD dataset and Confusing-LeCaRD dataset was 90.95% and 94.64%, and the model was superior to TF-IDF, BM25 and BERT-PLI in all indicators.

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Driver fatigue state detection method based on multi-feature fusion
Hao-jie FANG,Hong-zhao DONG,Shao-xuan LIN,Jian-yu LUO,Yong FANG
Journal of ZheJiang University (Engineering Science)    2023, 57 (7): 1287-1296.   DOI: 10.3785/j.issn.1008-973X.2023.07.003
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The improved YOLOv5 object detection algorithm was used to detect the facial region of the driver and a multi-feature fusion fatigue state detection method was established aiming at the problem that existing fatigue state detection method cannot be applied to drivers under the epidemic prevention and control. The image tag data including the situation of wearing a mask and the situation without wearing a mask were established according to the characteristics of bus driving. The detection accuracy of eyes, mouth and face regions was improved by increasing the feature sampling times of YOLOv5 model. The BiFPN network structure was used to retain multi-scale feature information, which makes the prediction network more sensitive to targets of different sizes and improves the detection ability of the overall model. A parameter compensation mechanism was proposed combined with face keypoint algorithm in order to improve the accuracy of blink and yawn frame number. A variety of fatigue parameters were fused and normalized to conduct fatigue classification. The results of the public dataset NTHU and the self-made dataset show that the proposed method can recognize the blink and yawn of drivers both with and without masks, and can accurately judge the fatigue state of drivers.

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Research progress of YOLO detection technology for traffic object
Hongzhao DONG,Shaoxuan LIN,Yini SHE
Journal of ZheJiang University (Engineering Science)    2025, 59 (2): 249-260.   DOI: 10.3785/j.issn.1008-973X.2025.02.003
Abstract   HTML PDF (3207KB) ( 1550 )  

The development and research status of YOLO algorithm in traffic object detection were systematically summarized from the perspective of the three core elements of 'people-vehicle-road' in order to comprehensively analyze the important role of YOLO (You Only Look Once) algorithm in improving traffic safety and efficiency. The commonly used evaluation indexes of YOLO algorithm were outlined, and the practical significance of these indexes in traffic scenarios was elaborately expounded. An overview of the core architecture of YOLO algorithm was provided, its development process was traced, and the optimization and improvement measures in each version iteration were analyzed. The research status and application scenarios of YOLO algorithm for traffic object detection were sorted out and discussed from the perspective of the three traffic objects 'people-vehicle-road'. The limitations and challenges of YOLO algorithm in traffic object detection were analyzed, and corresponding improvement methods were proposed. Future research focuses were anticipated, providing a research reference for the intelligent development of road traffic.

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Compound fault decoupling diagnosis method based on improved Transformer
Yu-xiang WANG,Zhi-wei ZHONG,Peng-cheng XIA,Yi-xiang HUANG,Cheng-liang LIU
Journal of ZheJiang University (Engineering Science)    2023, 57 (5): 855-864.   DOI: 10.3785/j.issn.1008-973X.2023.05.001
Abstract   HTML PDF (2584KB) ( 1476 )  

Most of the compound fault diagnosis methods regard the compound fault as a new single fault type, ignoring the interaction of internal single faults, and the fault analysis is vague in granularity and poor in interpretation. An improved Transformer-based compound fault decoupling diagnosis method was proposed for industrial environments with very little compound fault data. The diagnosis process included pre-processing, feature extraction and fault decoupling. With introducing the decoder of the Transformer, the cross-attention mechanism enables each single fault label to adaptively in the extracted feature layer focus on the discriminative feature region corresponding to the fault feature and predicts the output probability to achieve compound fault decoupling. Compound fault tests were designed to verify the effectiveness of the method compared with the advanced algorithms. The results showed that the proposed method had high diagnostic accuracy with a small number of single fault training samples and a very small number of compound fault training samples. The compound fault diagnosis accuracy reached 88.29% when the training set contained only 5 compound fault samples. Thus the new method has a significant advantage over other methods.

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Multi-agent pursuit and evasion games based on improved reinforcement learning
Ya-li XUE,Jin-ze YE,Han-yan LI
Journal of ZheJiang University (Engineering Science)    2023, 57 (8): 1479-1486.   DOI: 10.3785/j.issn.1008-973X.2023.08.001
Abstract   HTML PDF (1158KB) ( 1407 )  

A multi-agent reinforcement learning algorithm based on priority experience replay and decomposed reward function was proposed in multi-agent pursuit and evasion games. Firstly, multi-agent twin delayed deep deterministic policygradient algorithm (MATD3) algorithm based on multi-agent deep deterministic policy gradient algorithm (MADDPG) and twin delayed deep deterministic policy gradient algorithm (TD3) was proposed. Secondly, the priority experience replay was proposed to determine the priority of experience and sample the experience with high reward, aiming at the problem that the reward function is almost sparse in the multi-agent pursuit and evasion problem. In addition, a decomposed reward function was designed to divide multi-agent rewards into individual rewards and joint rewards to maximize the global and local rewards. Finally, a simulation experiment was designed based on DEPER-MATD3. Comparison with other algorithms showed that DEPER-MATD3 algorithm solved the over-estimation problem, and the time consumption was improved compared with MATD3 algorithm. In the decomposed reward function environment, the global mean rewards of the pursuers were improved, and the pursuers had a greater probability of chasing the evader.

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Multi-distortion type underwater image enhancement based on improved CycleGAN
Zhenming LV,Shaojiang DONG,Zongyou XIA,Xiaoyan MOU,Mingquan WANG
Journal of ZheJiang University (Engineering Science)    2025, 59 (6): 1148-1158.   DOI: 10.3785/j.issn.1008-973X.2025.06.006
Abstract   HTML PDF (4587KB) ( 1332 )  

A multi-distortion type underwater image enhancement algorithm based on improved CycleGAN was proposed, aiming at the difficulties of underwater image blurring, low contrast and image distortion recognition caused by various factors such as scattering, absorption and color deviation. Firstly, in order to improve the image enhancement effect, Auto-Encoder+Skip-connection network structure was used in the generator of CycleGAN, and global color correction structure was added for global enhancement in terms of pixel as well as color, so as to better capture the color information in underwater images. Secondly, a multidimensional perceptual discriminator was designed to learn the global and local features of the image. This discriminator payed more attention to the local details of the image, effectively targeted scattering and color noise, perceived the image from a multidimensional space, and had a stronger ability to extract the features, thereby enhancing the accuracy of image discrimination. Finally, the experimental results on EUVP, UIEB and U45 datasets showed that the proposed method achieved better results, compared with other algorithms. In processing multi-distortion types of underwater images, the algorithm’s SSIM indicator was higher than that of the second place by an average of 1.57%, the PSNR indicator was higher by 1.836%, the UIQM indicator was higher by 1.324%, and the UCIQE indicator was higher by 1.086%. The proposed method performed well in processing color and noise details.

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Pavement distress situation prediction method based on graph neural network
Zechao MA,Xiaoming LIU,Hanqing XIA,Weiqiang WANG,Jiuzeng WANG,Haitao SHEN
Journal of ZheJiang University (Engineering Science)    2024, 58 (12): 2596-2608.   DOI: 10.3785/j.issn.1008-973X.2024.12.019
Abstract   HTML PDF (1111KB) ( 1320 )  

A road pavement distress situation forecasting method employing graph convolutional networks was introduced, addressing the prediction problem of road pavement distress generation and deterioration. Firstly, a topological network was established through clustering algorithms, selecting the main influencing factors of the target pavement distress during its evolution. Subsequently, to enhance the expressive capability of the graph neural network for distress information, a graph topology enhancement method was employed, constructing views related to distress information from both static and dynamic aspects. Finally, an enhanced graph neural network (GNN) architecture was applied, by incorporating attention mechanisms in the view dimension to adjust the influence of different views and utilizing Transformer and GRU modules in the temporal dimension to enhance the predictive performance of the model for pavement distress states over extended time sequences. The internal calibration tests of the model, including ablation studies, multi-sample testing, and hyperparameter control group validation, demonstrated the applicability and stability of the proposed model. For the large and sparse pavement disease dataset, the mean absolute error of this model converged within 4.0, which was better than the results of the traditional prediction algorithms in terms of comprehensive performance.

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Survey of multi-objective particle swarm optimization algorithms and their applications
Qianlin YE,Wanliang WANG,Zheng WANG
Journal of ZheJiang University (Engineering Science)    2024, 58 (6): 1107-1120.   DOI: 10.3785/j.issn.1008-973X.2024.06.002
Abstract   HTML PDF (1559KB) ( 1274 )  

Few existing studies cover the state-of-the-art multi-objective particle swarm optimization (MOPSO) algorithms. To fill the gap in this area, the research background of multi-objective optimization problems (MOPs) was introduced, and the fundamental theories of MOPSO were described. The MOPSO algorithms were divided into three categories according to their features: Pareto-dominated-based MOPSO, decomposition-based MOPSO, and indicator-based MOPSO, and a detailed description of their existing classical algorithms was also developed. Next, relevant evaluation indicators were described, and seven representative algorithms were selected for performance analysis. The experimental results demonstrated the strengths and weaknesses of each of the traditional MOPSO and three categories of improved MOPSO algorithms. Among them, the indicator-based MOPSO performed better in terms of convergence and diversity. Then, the applications of MOPSO algorithms in production scheduling, image processing, and power systems were briefly introduced. Finally, the limitations and future research directions of the MOPSO algorithm for solving complex optimization problems were discussed.

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Improved method for blockchain Kademlia network based on small world theory
Yue ZHAO,He ZHAO,Haibo TAN,Bin YU,Wangnian YU,Zhiyu MA
Journal of ZheJiang University (Engineering Science)    2024, 58 (1): 1-9.   DOI: 10.3785/j.issn.1008-973X.2024.01.001
Abstract   HTML PDF (1194KB) ( 1259 )  

An improved method for the blockchain Kademlia network based on small world theory was proposed aiming at the issue of sacrificing security to improve scalability in the current research of the blockchain Kademlia network. The idea of the small world theory was followed, and a probability formula for replacing expansion nodes was proposed. The probability was inversely proportional to the distance between nodes. The number of node replacements and additional nodes could be flexibly adjusted according to actual conditions. The theoretical analysis and experimental verification demonstrate that the network transformed by this method can reach a stable state. The experimental results showed that the transmission hierarchy required for broadcasting transaction messages throughout the network was reduced by 15.0% to 30.8% and the rate of locating nodes was increased. The level of network structure was reduced and network security was enhanced compared to other optimization algorithms that modify the network structure.

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Three-dimensional sector automatic design based on improved NSGA-II algorithm
Yingfei ZHANG,Xiaobing HU,Hang ZHOU,Xuzeng FENG
Journal of ZheJiang University (Engineering Science)    2025, 59 (2): 413-422.   DOI: 10.3785/j.issn.1008-973X.2025.02.019
Abstract   HTML PDF (1634KB) ( 1239 )  

An improved non-dominated sorting genetic algorithm II (NSGA-II) was proposed in order to address the challenges of time-consuming manual airspace sectorization and the difficulty in comparing the quality of different sectorization schemes. A three-dimensional multi-objective optimization model for sectorization was established by using a grid-region-sector hierarchy in order to balance controllers’ workload within sectors and reduce workload differences between sectors. A fitness evaluation operator, a probability-adaptive combination crossover operator and a dynamic mutation operator were incorporated in the NSGA-II algorithm in order to enhance the number of feasible solutions, solution diversity and computational efficiency. A simulation was conducted for the automatic 3D sectorization of Xi'an high-altitude airspace. Results showed that the optimized scheme improved workload balance within sectors by 37% and reduced inter-sector workload by 24% compared with the current sectorization configuration. The proposed improved NSGA-II provided a broader range of options for decision-makers with varying preferences compared with traditional weighted multi-objective optimization algorithms.

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Interface opening strategy of high-speed railway station buildings in response to climate and verification by simulation
Nan WANG,Jin-liu WANG,Cong-hong LIU
Journal of ZheJiang University (Engineering Science)    2023, 57 (6): 1071-1079.   DOI: 10.3785/j.issn.1008-973X.2023.06.002
Abstract   HTML PDF (1898KB) ( 1231 )  

A design strategy through appropriately opening the passing space interface in response to climate was proposed as a solution to high energy consumption and formal convergence within the high-speed railway station buildings. Performance simulation tools based on building information modeling (BIM) were used to build a typical model, and the opening time period for different climate zones were determined according to wind and thermal environment simulation analysis. Results show that it is feasible to open up the passing space interface, meeting the requirement of indoor thermal comfort, in the case of a typical summer calculation day in climate zones except in hot summer and warm winter zone (Guangzhou as an example). Meanwhile, during the particular time periods of a year, interface opening is beneficial to energy savings and emission reduction in station buildings, especially in hot summer and cold winter zone (Shanghai as an example) and cold zone (Beijing as an example). The energy-savings reached up to 44.8% and 32.2%, respectively, as well as carbon reduction rates of 36.1% and 21.3%. Hence, the proposed strategy has significant application potential in the green design schemes of high-speed railway station buildings and can explore ideas for regional expression of spatial forms.

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Lightweight recognition algorithm for OCT images of fundus lesions
Xiao-hu HOU,Xiao-fen JIA,Bai-ting ZHAO
Journal of ZheJiang University (Engineering Science)    2023, 57 (12): 2448-2455.   DOI: 10.3785/j.issn.1008-973X.2023.12.012
Abstract   HTML PDF (1143KB) ( 1212 )  

A lightweight classification model MB-CNN for optical coherence tomography (OCT) images was proposed to accurately and conveniently identify multiple types of fundus lesions. By reducing the number of convolution cores and adjusting the proportion of convolution blocks in each stage, a lightweight backbone network L-Resnet was designed, and the extraction of deep-layer semantic information was enhanced by deepening the network depth. The multi-scale convolution block MultiBlock was designed using depthwise seperable convolution, and the features of the lesion area was mined. Different convolution kernels were used to extract the lesions features of different sizes to improve the recognition ability of the network to the OCT image of the lesion. The feature fusion module FFM was constructed, and the shallow layer information and deep layer information were fused, the texture and semantic information of the pathological features were extracted, and the recognition ability of small target lesions was improved. Experimental result showed that the overall classification accuracy of MB-CNN in the three datasets of UCSD, Duke and NEH was 97.2%, 99.92% and 94.37% respectively, the amount of model parameters were significantly reduced. The proposed model can classify various fundus lesions.

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Structure and property of 2219 aluminum alloy fabricated by droplet+arc additive manufacturing
Yongchao WANG,Zhengying WEI,Pengfei HE
Journal of ZheJiang University (Engineering Science)    2024, 58 (8): 1585-1595.   DOI: 10.3785/j.issn.1008-973X.2024.08.006
Abstract   HTML PDF (7116KB) ( 1186 )  

A new arc additive manufacturing process—droplet+arc additive manufacturing (DAAM) technology was applied to manufacture aluminum alloy samples in order to improve the quality and the efficiency of aluminum alloy. A new droplet generation system (DGS) was applied instead of the conventional wire feeding system, which makes the material addition and arc energy independent of each other. The formed material is 2219 aluminum alloy, and a trace amount of Mg element was added through the DGS. A thin-walled structure was deposited using the DAAM system at a significantly higher deposition rate (160 $ {\mathrm{m}\mathrm{m}}^{3}/\mathrm{s} $) than conventional wire and arc additive manufacturing techniques. The microstructure of the cross section of the thin-walled structure was observed and analyzed. Results showed that the grain morphology of the thin-walled structure was dominated by columnar crystals and exhibited a periodic distribution of inner-layer columnar crystals and inter-layer equiaxed crystals. The average tensile strengths in the horizontal and vertical directions were 455.4 MPa and 417.0 MPa after T6 heat treatment, while the yield strengths were 342.2 MPa and 316.4 MPa, respectively. The comparison results with the previous studies show that the addition of Mg element increases the yield strength of 2219 aluminum alloy, but leads to a corresponding decrease in elongation.

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