As one of the most widely used technologies in software testing, fuzzing technology has been applied to network protocol vulnerability detection, and various network protocol fuzzers have been proposed. In this study, we first analyze and summarize some typical network protocol fuzzers to highlight the challenges when addressing stateful network protocol fuzzing. Then, a state-driven smart graybox protocol fuzzer (SGPFuzzer) is proposed to deal with these challenges. Finally, we evaluate SGPFuzzer on two widely used protocol implementations (LightFTP and tinyDTLS). The results show that SGPFuzzer outperforms Boofuzz and AFL in path coverage, unique crashes and the first time crash to crash, and it triggers a known bug which can’t be trigged by the other two tools, fully proving its effectiveness and practicability.

This letter addresses the problem of robust global predefined-time synchronization for a class of nonlinear systems, in which the settling-time is explicit compared with the conventional fixed-time synchronization. Specially, the designed control scheme is smooth, namely differentiable, which is distinguished from the traditional fast control methods containing the signum function. By the Lyapunov stability analysis, the sufficient criterion is derived for achieving the global predefined-time synchronization. More importantly, the obtained results have been directly applied into synchronizing two chaotic systems. Finally, the numerical simulation on predefined-time synchronization of chaotic systems is arranged for verifying the correction and effectiveness of theoretical results.

This article investigates the issues of predefined-time global phase agreement (PA) and frequency synchronization (FS) for both identical and non-identical coupled Kuramoto oscillators by developing distributed chattering-free control protocols. Unlike traditional finite-/fixed-time convergence, the upper bounds of settling-time for achieving the predefined-time PA and FS are explicit constants, which are tunable and set beforehand without depending on the network information, initial conditions, and controlling parameters. In particular, the proposed control protocols are differentiable, namely chattering-free, which do not comprise the conventional discontinuous absolute value and/or signum functions anymore. Therefore, the undesirable chattering problem is effectively overcome. Then, in the light of the second Lyapunov method, the sufficient conditions are deduced for guaranteeing the predefined-time global PA and FS of Kuramoto-oscillator networks accordingly. Finally, the numerical results validate the effectiveness of the proposed chattering-free control schemes.

With the development of cloud-edge collaborative computing, cloud computing has become crucial in data analysis and data processing. OpenStack and Docker are important components of cloud computing, and the integration of the two has always attracted widespread attention in industry. The scheduling mechanism adopted by the existing fusion solution uses a uniform resource weight for all containers, and the computing nodes resources on the cloud platform is unbalanced under differentiated resource requirements of the containers. Therefore, considering different network communication qualities, a load-balancing Docker scheduling mechanism based on OpenStack is proposed to meet the needs of various resources (CPU, memory, disk, and bandwidth) of containers. This mechanism uses the precise limitation strategy for container resources and a centralized strategy for container resources as the scheduling basis, and it generates exclusive weights for containers through a filtering stage, a weighing stage based on weight adaptation, and a non-uniform memory access (NUMA) lean stage. The experimental results show that, compared with Nova-docker and Yun, the proposed mechanism reduces the resource load imbalance within a node by 57.35% and 59.00% on average, and the average imbalance between nodes is reduced by 53.53% and 50.90%. This mechanism can also achieve better load balancing without regard to bandwidth.