The three volume set LNCS 13155, 13156, and 13157 constitutes the refereed proceedings of the 21st International Conference on Algorithms and Architectures for Parallel Processing, ICA3PP 2021, which was held online during December 3-5, 2021. Part II, LNCS 13156: Software systems and efficient algorithms;

Deep Learning Models and Applications.- CRFST-GCN :A Deeplearning Spital-Temporal Frame to Predict Traffic Flow.- BFR-RetinaNet: An Improved RetinaNet Model for Vehicle Detection in Aerial Images.- Learning Knowledge Graph Embeddings by Multi-Attention Mechanism for Link Prediction.- GlowImp: Combining GLOW and GAN for Multivariate Time Series Imputation.- Accurate Indoor Localization Using Magnetic Sequence Fingerprints with Deep Learning.- Wasserstein Graph Auto-Encoder.- Fine-grained Activity Recognition Based on Features of Action Subsegments and Incremental Broad Learning.- ADFA-LSTM: An Abnormal Trajectory Prediction Method Based On Bionic Neural Network.- Online Multiple Object Tracking Algorithm based on Heat Map Propagation.- Software Systems and Efficient Algorithms.- Spatio-temporal Topology Routing Algorithm for Opportunistic Network Based on Self-Attention Mechanism.- TSAEns: Ensemble Learning for KPI Anomaly Detection.- Towards Transferable Adversarial Examples using Meta Learning.- Temporal Convolution Network Based on Attention for Intelligent Anomaly Detection of Wind Turbine Blades.- Error Serial Episodes Discovery from Mobile Payment Log in Distributed ETC.- Parallel Cache Prefetching for LSM-Tree based Store: From Algorithm to Evaluation.- A Hybrid TLBO-TS Algorithm based Mobile Service Selection for Composite Services.- UPM-DMA: An Efficient Userspace DMA-Pinned Memory Management Strategy for NVMe SSD.- AHOA: Adaptively Hybrid Optimization Algorithm for Flexible Job-shop Scheduling Problem.- Trace-Navi: A High-Accuracy Indoor Navigation System based on Real-Time Activity Recognition and Discrete Trajectory Calibration.- Iterative Filling Incomplete Fingerprint Map Based on Multi-directional Signal Propagation in Large-scale Scene            .- Dynamic Adjustment Policy of Search Driver Matching Distance via Markov Decision Process.- A Multi-Precision Quantized Super-Resolution Model Framework.- An Optimized GPU Implementation of Weakly-compressible SPH using CUDA-based strategies.- A Heterogeneous Multi-Core Network-on-Chip Mapping Optimization Algorithm.- A Novel 3D Intelligent Cluster Method for Malicious Traffic Fine-grained Classification.- Predicting Students’ Academic Performance Based on Improved PSO-Xgboost: A Campus Behavior Perspective.- Motion-sequence Authentication System: guard for smart phones.- Edge Computing and Edge Intelligence.- Joint Optimization Scheme of Multi-service Replication and Request Offloading in Mobile Edge Computing.- Flying MEC: Online Task Offloading, Trajectory Planning and Charging Scheduling for UAV-assisted MEC.- Multiple Workflows Offloading Based on Deep Reinforcement Learning in Mobile Edge Computing.- An Optimized Greedy-based Task Offloading Method for Mobile Edge Computing.- Location Aware Workflow Migration Based on Deep Reinforcement Learning in Mobile Edge Computing.- Recode-Decode-and-Compare: An Efficient Verification Scheme for Coded Edge Computing against Collusion Attack.- MGFL: Multi-granularity Federated Learning in Edge Computing Systems.- Energy Efficient Priority-Based Task Scheduling for Computation Offloading in Fog Computing.- Space-Heuristic Navigation and Occupancy Map Prediction for Robot Autonomous Exploration.- Service Dependability and Security Algorithms.- Edge DDoS attack detection method based on software defined networks.- GradMFL: Gradient Memory-based Federated Learning for Hierarchical Knowledge Transferring over Non-IID Data.- Linear Coded Federated Learning.- Verifiable Dynamic Searchable Symmetric Encryption with Forward Privacy in Cloud-assisted E-Healthcare Systems.- Security Analysis of Poisoning Attacks Against Multi-agent Reinforcement Learning.- A blockchain-based proxy oriented cloud storage public audit scheme for low-performance terminal devices.- Sunspot: A Decentralized Framework Enabling Privacy for Authorizable Data Sharing on Transparent Public Blockchains.- A Novel Protection method of continuous location sharing based on local differential privacy and conditional random field.- An Intelligent Allocation Mechanism Based on Ethereum Blockchain in Microgrid.- Data Science.- Multi-Layer Adaptive Sampling for Per-Flow Spread Measurement.- Transformer-based Rating-Aware Sequential Recommendation.- An effective single-pass approach for estimating the Φ-quantile in data streams.- Fed-Tra: Improving Accuracy of Deep Learning Model on Non-IID Data in Federated Learning.