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Masked autoencoder enhanced dynamic heterogeneous graph representation learning model
Haoran YUAN, Huan LIU, Pengfei JIAO, Zhidong ZHAO, Xianfei ZHANG, Zunliang LIU
Journal of Computer Applications    2026, 46 (6): 1728-1737.   DOI: 10.11772/j.issn.1001-9081.2025060754
Abstract59)   HTML1)    PDF (1188KB)(13)       Save

Real-world networks are often composed of multiple types of entities and interaction relationships, with topological structure and attributes evolving with time continuously. The heterogeneity and dynamics inherent in such networks can be fully described by Dynamic Heterogeneous Graph (DHG). To solve the problems of coarse spatio-temporal information fusion and heavy reliance of the supervised learning paradigm on manual labels in the existing DHG representation learning models, a Masked AutoEncoder (MAE) enhanced DHG representation learning model was proposed. Firstly, heterogeneous spatial information was fused through a multi-level attention structure, and temporal information was fused across snapshots. Then, representation information of nodes was enriched by leveraging the reconstruction loss of the masked autoencoder. Experimental results show that improvements of at least 1.26 to 3.99 percentage points in Area Under the receiver operating Characteristic curve (AUC) are achieved by the proposed model on link prediction tasks compared to baseline models on multiple real-world datasets. It can be seen that the proposed model provides an effective self-supervised framework for DHG representation learning, facilitating more precise capture of heterogeneous information and dynamic evolution laws in real networks.

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Review of vision-language model architecture development
Ziquan LIU, Xuyang SHI, Ke LI, Liang LIU, Zhewei ZHU
Journal of Computer Applications    2026, 46 (6): 1703-1711.   DOI: 10.11772/j.issn.1001-9081.2025060695
Abstract220)   HTML4)    PDF (1005KB)(53)       Save

With the advancement of deep learning technologies, artificial intelligence has been driven to evolve from single-modality intelligence toward multimodal intelligence. Vision?Language Models (VLMs), which serve as the pivotal means of bridging vision and language, have been established as a core research area. Aiming at the technological evolution of VLMs, architecture development of VLM was reviewed systematically, and the core technologies and latest research progress in this field were summarized. Firstly, the progression of VLM from early explorations to the current flourishing state was traced, key technological nodes and development trends were analyzed, and a technology roadmap with “architecture development” as the core theme was delineated. Secondly, the current foundational techniques of VLM were analyzed deeply, including core architectures built around vision encoders, language encoders, and cross‐modal fusion mechanisms, as well as key pretraining optimization objectives such as Masked Language Modeling (MLM), Masked Image Modeling (MIM), and Contrastive Learning (CL). Concurrently, the mainstream datasets, which VLM pretraining relies on, such as COCO and LAION-5B, were listed systematically. Finally, representative VLMs were compared and analyzed to discover the relationships among model performance, data scale, architectural innovations, and training strategies, and the advantages and limitations of the related core technologies were commented, thereby providing a comprehensive VLM technology map for researchers of related fields, and offering reference and inspiration for future research.

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Auxiliary diagnostic method for retinopathy based on dual-branch structure with knowledge distillation
Sijie NIU, Yuliang LIU
Journal of Computer Applications    2025, 45 (5): 1410-1414.   DOI: 10.11772/j.issn.1001-9081.2024060856
Abstract397)   HTML8)    PDF (1274KB)(78)       Save

When using traditional models for the early diagnosis of retinopathy in high-risk patients with Diabetic Nephropathy (DN), the diagnostic accuracy is often compromised due to limited and category imbalanced retinal images of diabetic patients. To address this issue, an auxiliary diagnostic method for retinopathy based on dual-branch structure with knowledge distillation was proposed to improve the recognition capability for minority categories. Firstly, a teacher network pre-trained on large medical datasets was employed to guide the student network's learning process, transferring acquired knowledge to improve the student network's generalization ability and mitigate data scarcity. Secondly, a dual-branch structure was proposed in the student network. Branch 1 utilized a rebalancing strategy with Focal Loss function to emphasize challenging samples by adjusting loss function weights, while Branch 2 employed a Category Attention Module (CAM) to learn discriminative features for each category, preventing model bias towards majority categories. These two branches respectively promoted classifier learning and feature learning to alleviate category imbalance. Evaluated on clinically collected retinal image data, experimental results demonstrate that the proposed method achieves 1.05 and 1.53 percentage points improvements in accuracy and specificity respectively compared with Lesion-aware Attention Model (LAM) in screening tasks involving 66 cases (89 eyes) of high-risk patients with DN. The proposed method improves the recognition accuracy of DN and realizes the auxiliary diagnosis of retinal diseases.

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Small target detection method in UAV images based on fusion of dilated convolution and Transformer
Lin WANG, Jingliang LIU, Wuwei WANG
Journal of Computer Applications    2024, 44 (11): 3595-3602.   DOI: 10.11772/j.issn.1001-9081.2023111575
Abstract660)   HTML6)    PDF (1433KB)(666)       Save

A multi-scale dilated convolution based Unmanned Aerial Vehicle (UAV) image target detection algorithm Swin-Det was proposed to address the issues of complex target scenes, diverse scales of targets, dense small targets and severe occlusion of targets in UAV aerial images. Firstly, Swin Transformer was used as the backbone feature extraction network, and a Spatial Information Blending Module (SIBM) was introduced into the backbone network to solve the problem of fuzziness in target information due to occlusion between objects. Secondly, a Fusion of Dilation Feature Pyramid Network (FDFPN) was proposed to fuse feature information through multi-branch dilated convolution, thereby effectively improving the receptive field of the network and the reuse of feature information, so that the model was able to learn detailed features of different dimensions. Finally, the issues of mismatches in the prediction area and sample imbalance were addressed by using linear interpolation method and multi-task loss function, thereby improving the detection precision of the model. Experimental results on VisDrone dataset show that the Swin-Det algorithm reaches a mean Average Precision (mAP) of 27.2%, which is 4.1 percentage points higher than that of the original Swin Transformer, and converges faster under the same training batch. It can be seen tha the Swin-Det algorithm can achieve high-precision detection of UAV image targets in complex scenes.

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Non-overlapping community detection with imbalanced community sizes
Shiliang LIU, Yi WANG, Yinglong MA
Journal of Computer Applications    2024, 44 (11): 3396-3402.   DOI: 10.11772/j.issn.1001-9081.2023101536
Abstract413)   HTML2)    PDF (659KB)(102)       Save

Community detection helps to comprehend the complex structure of social networks, but most of the existing community detection methods do not consider the imbalanced sizes of communities to detect, and the discovered community structures are relatively single with low accuracy. Therefore, a non-overlapping community detection method based on Local Expansion of Initial Community Structure (LEICS) was proposed. LEICS was divided into three stages: in the first stage, the initial community structures with different scales were detected by utilizing the hierarchical structure information and local structure information of the network; in the second stage, the initial community was expanded by calculating the connection intensity between the node and the nodes in the community and the modularity contribution of the node, and then using the Label Propagation Algorithm (LPA) to deal with the rest of the nodes; in the third stage, for unstable communities with size smaller than the average community size, the nodes were redistributed to further optimize the results of community detection. Experimental results on twelve datasets of real-world networks and Lancichinetti-Fortunato-Radicchi (LFR) simulated networks show that compared to the suboptimal Local Balanced Label Diffusion (LBLD) algorithm, LEICS improves the Normalized Mutual Information (NMI) by at least 5 percentage points on Polbooks and YouTube networks, and the accuracy and robustness of LEICS in both small-size and large-size networks are fully validated, proving that LEICS can adapt to the imbalance of community size.

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Edge computing and service offloading algorithm based on improved deep reinforcement learning
Tengfei CAO, Yanliang LIU, Xiaoying WANG
Journal of Computer Applications    2023, 43 (5): 1543-1550.   DOI: 10.11772/j.issn.1001-9081.2022050724
Abstract953)   HTML18)    PDF (2400KB)(283)       Save

To solve the problem of limited computing resources and storage space of edge nodes in the Edge Computing (EC) network, an Edge Computing and Service Offloading (ECSO) algorithm based on improved Deep Reinforcement Learning (DRL) was proposed to reduce node processing latency and improve service performance. Specifically, the problem of edge node service offloading was formulated as a resource-constrained Markov Decision Process (MDP). Due to the difficulty of predicting the request state transfer probability of the edge node accurately, DRL algorithm was used to solve the problem. Considering that the state action space of edge node for caching services is too large, by defining new action behaviors to replace the original actions, the optimal action set was obtained according to the proposed action selection algorithm, so that the process of calculating the action behavior reward was improved, thereby reducing the size of the action space greatly, and improving the training efficiency and reward of the algorithm. Simulation results show that compared with the original Deep Q-Network (DQN) algorithm, Proximal Policy Optimization (PPO) algorithm and traditional Most Popular (MP) algorithm, the total reward value of the proposed ECSO algorithm is increased by 7.0%, 12.7% and 65.6%, respectively, and the latency of edge node service offloading is reduced by 13.0%, 18.8% and 66.4%, respectively, which verifies the effectiveness of the proposed ECSO algorithm and shows that the ECSO can effectively improve the offloading performance of edge computing services.

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Optimal storing strategy based on small files in RAMCloud
YING Changtian YU Jiong LU Liang LIU Jiankuang
Journal of Computer Applications    2014, 34 (11): 3104-3108.   DOI: 10.11772/j.issn.1001-9081.2014.11.3104
Abstract465)      PDF (782KB)(750)       Save

RAMCloud stores data using log segment structure. When large amount of small files store in RAMCloud, each small file occupies a whole segment, so it may leads to much fragments inside the segments and low memory utilization. In order to solve the small file problem, a strategy based on file classification was proposed to optimize the storage of small files. Firstly, small files were classified into three categories including structural related, logical related and independent files. Before uploading, merging algorithm and grouping algorithm were used to deal with these files respectively. The experiment demonstrates that compared with non-optimized RAMCloud, the proposed strategy can improve memory utilization.

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Multi-objective evolutionary algorithm for grid job scheduling based on adaptive neighborhood
YANG Ming XUE Sheng-jun CHEN Liang LIU Yong-sheng
Journal of Computer Applications    2012, 32 (03): 599-602.   DOI: 10.3724/SP.J.1087.2012.00599
Abstract1299)      PDF (608KB)(907)       Save
A new adaptive neighborhood Multi-Objective Grid Task Scheduling Algorithm (ANMO-GTSA) was proposed in this paper for the multi-objective job scheduling collaborative optimization problem in grid computing. In the ANMO-GTSA, an adaptive neighborhood method was applied to find the non-inferior set of solutions and maintain the diversity of the multi-objective job scheduling population. The experimental results indicate that the algorithm proposed in this paper can not only balance the multi-objective job scheduling, but also improve the resource utilization and efficiency of task execution. Moreover, the proposed algorithm can achieve better performance on time-dimension and cost-dimension than the traditional Min-min and Max-min algorithms.
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Snapshot K neighbor query processing on moving objects in road networks
LU Bing-liang LIU Na
Journal of Computer Applications    2011, 31 (11): 3078-3083.   DOI: 10.3724/SP.J.1087.2011.03078
Abstract1252)      PDF (957KB)(513)       Save
The functionality of a framework that supported location-based services on moving objects in road networks was extended and Snapshot K Nearest Neighbor (SKNN) queries based on Mobile Network Distance Range (MNDR) queries was proposed using an on-disk R-tree to store the network connectivity and an in-memory grid structure to maintain the moving object position updates. The minimum and maximum number of grid cells of a given arbitrary edge in the space that were possibly affected were analyzed. The maximum bound that could be used in snapshot range query processing to prune the search space was shown. SKNN estimated the subspace containing the query results and used the subspace as range to efficiently compute the KNN POI from the query points to reduce I/O cost and time of query. Analysis shows that the maximum bound can be used in snapshot range query processing to prune the search space. The contrast experiments show that SKNN has better system throughput than S-GRID while scaling to hundreds of thousands of moving objects.
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New method for point cloud data reduction
ZHANG You-liang LIU Jian-yong FU Cheng-qun GUO Jie
Journal of Computer Applications    2011, 31 (05): 1255-1257.   DOI: 10.3724/SP.J.1087.2011.01255
Abstract2115)      PDF (444KB)(1111)       Save
The reduction and storage of enormous point cloud data is a crucial link in reverse model reconstruction. Considering the features of point cloud data by single station laser scanning, a new method — grid sector method was put forward for its reduction and storage. Point cloud data could be filtered and stored only by traversal. This method was realized on VC++ 6.0. Multi-station scanning of point cloud registration and stitching would be more quickly and efficiently, if the site goes through the fan in a single grid after treatment. Based on the contrast with traditional compressing methods, this paper analyzed its characteristics and proved its applicability in battlefield terrain digitization.
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Cooperative particle swarm optimization
Huai-liang LIU Rui-juan SU Ruo-ning XU Ying GAO
Journal of Computer Applications    2009, 29 (11): 3068-3073.  
Abstract2139)      PDF (1065KB)(1565)       Save
To solve the premature convergence problem of Particle Swarm Optimization (PSO), two new methods were introduced to improve the performance cooperatively: When particles’ fitness values were worse than the average, the dynamic Zaslavskii chaotic map formula was devised to modify the inertia weight and velocity, which can make particles break away from the local best and search the global best dynamically; On the contrary, when fitness values were better than or equal to the average, the introduced dynamic nonlinear functions were used to modify the inertia weight and velocity, which can make particles retain favorable conditions and converge to the global best continually. Two methods coordinate dynamically, and make two dynamic swarms cooperate to evolve. Experimental results demonstrate that the new introduced algorithm outperforms several other famous improved PSO algorithms on many well-known benchmark problems.
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