Formation Control Algorithms for Multi-UAV Systems with Unstable Topologies and Hybrid Delays

Multi-UAV systems rely on the communication network to exchange mission-critical data for their coordination and deployment, while communication delays could cause significant challenges to both tasks. The impact of the delays becomes even more severe if the delay, network structure and formation are all time-varying, a common challenge faced by real-world multiUAV systems. To address this challenge, we consider time-varying delays that exist in multiple channels caused by transmitting information and internal delays that exist in UAVs themselves caused by obtaining and processing their own data. We design an effective distributed formation control protocol for a multiUAV system to achieve time-varying formation; this protocol is particularly useful for dealing with time-varying multi-UAV network topologies as well. We provide rigorous convergence analysis for different scenarios with or without hybrid delays and obtain sufficient conditions for achieving the time-varying formation. Furthermore, we propose an algorithm for quantifying the maximum delay allowed by the system. Based on the designed formation algorithm, a deployment strategy is proposed to coordinate multi-UAV systems in a practical environment. Numerical analysis and UAV hardware experiments are conducted to evaluate the performance of the theoretical results and investigate the feasibility of generated flight trajectories

Comparative efficacy and safety of pemetrexed and crizotinib in Chinese patients with advanced lung cancer: A preliminary clinical trial

Purpose: To carry out a pilot clinical trial to compare the effectiveness and safety of crizotinib and pemetrexed-based regimens in Chinese patients with advanced lung cancer (ALC). Method: Patients with confirmed diagnosis of ALC were randomly grouped and treated intravenously with a mixture of pemetrexed (500 mg/m2 ) and cisplatin (75 mg/m2 ) plus BSC, or crizotinib (250 mg BD) + BSC in a 1:1 ratio. Efficacy parameters such as overall survival (OS), objective response rate (ORR), and progression-free survival (PFS) were assessed after pemetrexed and crizotinib treatments. The safety of pemetrexed and crizotinib was determined. Survival time with respect to disease progression was also assessed. Results: Pemetrexed-based regimens showed significantly higher OS and PFS than crizotinib (OS: median = 13.23 and 7.47 months, respectively; p < 0.001; PFS: median = 11.32 and 4.17 months, respectively). Objective response was also favorable in the patients treated with pemetrexed, when compared with those given crizotinib. Pemetrexed-based regimen was superior to crizotinib in improving OS, PFS and ORR, and it offered significantly greater clinical benefits than crizotinib in Chinese patients with ALC. Conclusion: The results of clinical trial would help clinicians select appropriate therapeutic intervention for patients with ALC