This book constitutes the proceedings of the 21st International Conference on Parallel and Distributed Computing, Applications, and Technologies, PDCAT 2020, which took place in Shenzhen, China, during December 28-30, 2020.The 34 full papers included in this volume were carefully reviewed and selected from 109 submissions. They deal with parallel and distributed computing of networking and architectures, software systems and technologies, algorithms and applications, and security and privacy.  

Table of Contents:
Blood leukocyte object detection according to model-parameter transfer and deformable convolution.- Heterogeneous Software Effort Estimation via Cascaded Adversarial Auto-Encoder.- A Novel Distributed Reinforcement Learning Method for Classical Chinese Poetry Generation.- Memory Access Optimization of High-order CFD Stencil Computations on GPU.- The Dataflow Runtime Environment of DFC.- Adaptive Tensor-Train Decomposition for Neural Network Compression.- Development of a UAV path planning approach for multi-building inspection with minimal cost.- Construction of Completely Independent Spanning Tree based on Vertex Degree.- Distributed Algorithm for Truss Maintenance in Dynamic Graphs.- Short-term load forecasting based on CNN-BiLSTM with Bayesian Optimization and Attention Mechanism.- On The Non-ergodic Convergence Rate of The Directed Nonsmooth Composite Optimization.- 6D Pose Estimation Based on the Adaptive Weight of RGB-D Feature.- Blockchain-based Secure Outsourcing of Fully Homomorphic Encryption using Hidden Ideal Lattice.- Multiple Projections Learning for Dimensional Reduction.- Preventing DDoS Attacks on Bitcoin Memory Pool by the Dynamic Fee Threshold Mechanism.- The Compiler of DFC: A Source Code Converter that Transform the Dataflow Code to the Multi-threaded C Code.- Online Learning-Based Co-Task Dispatching with Function Configuration in Edge Computing.- System-Level FPGA Routing for Logic Verification with Time-Division Multiplexing.- Protein interresidue contact prediction based on deep learning and massive features from multi-sequence alignment.- See Fine Color from the Rough Black-and-White.- Data Aggregation Aware Routing for Distributed Training.- A New Integer Programming Model for the File Transfer Scheduling Problem.- Approximation Algorithms for the General Clustered Routing Problem.- Maximizing Group Coverage in Social Networks.- LightLayers: Parameter Efficient Dense and Convolutional Layers for Image Classification.- The Hybrid NavigationMethod in Face of Dynamic Obstacles.- A relaxed balanced lock-free binary search tree.- A Dynamic Parameter Tuning Method for High Performance SpMM. -Data Caching Based Transfer Optimization in Large Scale Networks.- Second-order Convolutional Neural Network based on Cholesky Compression Strategy.- Submodular Maximization with Bounded Marginal Values.- A streaming model for monotone lattice submodular maximization with a cardinality constraint.- The prize-collecting $k$-Steiner tree problem.- Optimal algorithm of Isolated toughness for Interval Graphs.- Graceful Performance Degradation in Apache Storm.