Nonlinear robust control of tail-sitter aircrafts in flight mode transitions

© 2018 Elsevier Masson SAS In this paper, a nonlinear robust controller is proposed to deal with the flight mode transition control problem of tail-sitter aircrafts. During the mode transitions, the control problem is challenging due to the high nonlinearities and strong couplings. The tail-sitter aircraft model can be considered as a nominal part with uncertainties including nonlinear terms, parametric uncertainties, and external disturbances. The proposed controller consists of a nominal H∞controller and a nonlinear disturbance observer. The nominal H∞controller based on the nominal model is designed to achieve the desired trajectory tracking performance. The uncertainties are regarded as equivalent disturbances to restrain their influences by the nonlinear disturbance observer. Theoretical analysis and simulation results are given to show advantages of the proposed control method, compared with the standard H∞control approach

Effects of Chemical Fertilizer Reduction Combined with Straw and Organic Fertilizer Application on Soil Acidification Mitigation and Erosion Control

[Objective] To demonstrate that appropriate application of straw and organic fertilizer can effectively improve soil quality, have a positive effect on soil acidification mitigation and erosion control. [Method] Acidified red soil was used as the research object and a comparative analysis was performed for the effects of conventional fertilization (CK), chemical fertilizer reduction (30%), straw returning (6 000 kg/hm2, FSM0), and the combination of chemical fertilizer reduction (30%) coupled with straw returning (6 000 kg/hm2) and different gradients of organic fertilizers (1 500, 3 000, 4 500 and 6 000 kg/hm2) (FSM1, FSM2, FSM3, and FSM4) on soil properties at different stages of rapeseed growth and rapeseed yield. [Results] The reduction of chemical fertilizers combined with straw and organic fertilizer application significantly (p < 0.05) improved soil acidity and nutrient status. Compared with CK, soil pH increased by 0.05~0.25 unit under the five treatments, while exchangeable H+, exchangeable Al3+, and exchangeable acids decreased by 10.82%~39.81%, 5.18%~22.10% and 5.67%~23.90%, respectively. Additionally, the total exchangeable base increased by 7.63%~34.68%, and the total nitrogen and organic matter contents in the soil also significantly increased (by 19.22%~62.86% and 18.43%~61.50%, respectively). Analysis of soil mechanics properties indicated that with the increase of organic fertilizer application, soil shear strength was significantly enhanced, while the cohesion and internal friction angle exhibited a trend of first increasing and then decreasing. Under FSM2 treatment, the shear strength, cohesion, and internal friction angle all reached their peak values, with a respective increase of 22.22%, 20.06% and 11.38% relative to CK. Economic benefit analysis revealed that FSM2 had the highest net income. [Conclusion] Based on soil acidification improvement, fertility enhancement, structural improvement, and rapeseed economic benefits, chemical fertilizer reduction (30%) coupled with straw returning (6 000 kg/hm2) and 3 000 kg/hm2 organic fertilizer application can be recommended as the optimal management strategy. The results of this study can provide a scientific foundation for improving soil acidification and increasing crop yields

The clinical outcome of pembrolizumab for patients with recurrent or metastatic squamous cell carcinoma of the head and neck: a single center, real world study in China

BackgroundThe KEYNOTE-048 and KEYNOTE-040 study have demonstrated the efficacy of pembrolizumab in recurrent or metastatic squamous cell carcinoma of the head and neck (R/M HNSCC), we conducted this real-world study to investigate the efficacy of pembrolizumab in patients with R/M HNSCC.MethodsThis is a single-center retrospective study conducted in the Shanghai Ninth People’s Hospital Affiliated to Shanghai Jiao Tong University School of Medicine (Shanghai, China). Between December 2020 and December 2022, a total of 77 patients with R/M HNSCC were included into analysis. The primary endpoint of the study was overall survival (OS), and the secondary endpoints were progression-free survival (PFS), overall response rate (ORR)and toxicity.Efficacy was assessed according to RECIST version 1.1.SPSS 27.0 and GraphPad Prism 8.0 software were utilized to perform the statistical analysis.ResultsBy the cut-off date (February 28, 2023), the median OS,PFS and ORR were 15.97 months,8.53 months and 48.9% in patients treated with the pembrolizumab regimen in the first line therapy. Among these patients, 17 patients received pembrolizumab with cetuximab,and 18 received pembrolizumab with chemotherapy.We observed no significant differences between two groups neither in median OS (13.9 vs 19.4 months, P=0.3582) nor PFS (unreached vs 8.233 months, P= 0.2807). In the ≥2nd line therapy (n=30), the median OS, PFS and ORR were 5.7 months, 2.58 months and 20% respectively. Combined positive score (CPS) was eligible from 54 patients. For first line therapy, the median OS and PFS were 14.6 and 8.53 months in patients with CPS ≥1, and median OS and PFS were 14.6 and 12.33 months in patients with CPS ≥20. The immune-related adverse events (irAEs) were occurred in the 31 patients (31/77, 40.26%), and the most common potential irAEs were hypothyroidism (25.97%), and pneumonitis (7.79%).ConclusionOur real-world results indicated that pembrolizumab regimen is a promising treatment in patients with R/M HNSC

Cooperative Green Technology Innovation of an E-Commerce Sales Channel in a Two-Stage Supply Chain

The potential broad market of green consumption has encouraged an increasing number of enterprises to carry out green technology innovation activities. This paper examines a two-stage supply chain of e-commerce sales channels under different cooperative models. We find that consumers’ green preferences are the main factor that affects green product market demand. The manufacturer and the retailer can raise the levels of green technology innovation and extend green promotional services to expand product market demand in online and offline channels. However, consumers’ e-commerce preferences and online free-riding behaviors affect the manufacturer’s sales channel choice. The retailer can improve the level of green promotional services to hold offline channel market demand, while promotional behaviors have a positive/negative spillover effect on online market demand if the level of free riding falls above/below consumers’ e-commerce preferences. The higher the cooperative level is, the later the manufacturer will open the online channel and close the offline channel to ensure a high level of green promotional service from the cooperative retailer. The results show that the stronger the level of cooperation among all members is, the better the economic, ecological, and social benefits will be. Therefore, we design a revenue-cost sharing contract that can effectively motivate green technology innovation and green promotional services and afford all members win-win profits.</jats:p

Backstepping control for gear transmission servo systems with unknown partially nonsymmetric deadzone nonlinearity

This paper deals with the output tracking control of gear transmission servo (GTS) systems in the presence of deadzone nonlinearity with nonsymmetric beak points and unknown parameters. A novel differentiable deadzone model with nonsymmetric break points is put forward, which greatly facilitates the control design for a class of mechanical systems in the presence of deadzone nonlinearity. A new smooth backstepping controller, based on the newly-developed model, is proposed for the nominal system. Then, guaranteed robust steady-state performance of the closed-loop system with parametric uncertainties is derived by using Lyapunov analysis for the perturbed nonlinear systems. Simulations are carried out to validate the proposed algorithm and analysis in this paper. </jats:p

Cooperative Green Technology Innovation of an E-Commerce Sales Channel in a Two-Stage Supply Chain

The potential broad market of green consumption has encouraged an increasing number of enterprises to carry out green technology innovation activities. This paper examines a two-stage supply chain of e-commerce sales channels under different cooperative models. We find that consumers’ green preferences are the main factor that affects green product market demand. The manufacturer and the retailer can raise the levels of green technology innovation and extend green promotional services to expand product market demand in online and offline channels. However, consumers’ e-commerce preferences and online free-riding behaviors affect the manufacturer’s sales channel choice. The retailer can improve the level of green promotional services to hold offline channel market demand, while promotional behaviors have a positive/negative spillover effect on online market demand if the level of free riding falls above/below consumers’ e-commerce preferences. The higher the cooperative level is, the later the manufacturer will open the online channel and close the offline channel to ensure a high level of green promotional service from the cooperative retailer. The results show that the stronger the level of cooperation among all members is, the better the economic, ecological, and social benefits will be. Therefore, we design a revenue-cost sharing contract that can effectively motivate green technology innovation and green promotional services and afford all members win-win profits

Supplier Encroachment Channel Selection on an Online Retail Platform

Online retail platforms offer encroachment opportunities for suppliers to directly sell products to consumers on the online market. However, how to select appropriate encroachment channels poses a significant challenge for suppliers. To solve this problem, we take one supplier selling products through an indirect reselling channel on a third-party online retail platform (TORP) as the base model, and further consider that the supplier can choose TORP agency selling, the owned channel, or both to encroach onto the online market. We hereby establish game-theoretical models to analyze the optimal strategy of supplier encroachment, the TORP preference, and the equilibrium channel strategy. The findings show that the supplier is always willing to encroach onto the online market through its own channel. Additionally, when the commission rate is low, the supplier will further encroach via the TORP agency selling channel. The TORP provides the agency selling channel for the supplier only when the commission rate exceeds a certain threshold. If the channel competition is not very fierce (the competition intensity is lower than 0.852) and the commission rate is moderate, dual-channel encroachment is the equilibrium channel strategy; otherwise, supplier-owned-channel encroachment is the equilibrium strategy. We extend our main models by incorporating supplier blockchain adoption and the cost differences between both parties to enhance practical applicability