Optimal tracking control for non-zero-sum games of linear discrete-time systems via off-policy reinforcement learning

In this article, a model-free off-policy reinforcement learning algorithm is applied to address the optimal tracking problem based on multiplayer non-zero-sum games for discrete-time linear systems. In contrast to the traditional method and the policy iteration method for solving the optimal tracking problems, the proposed algorithm operates with the system data rather than the knowledge of the system dynamics. For performing the proposed algorithm, an auxiliary augmented system is constructed via assembling the original system and the reference trajectory while a discount factor is introduced into the performance indexes. It is analyzed that the solutions of the proposed algorithm converge to the Nash equilibrium and the result is not influenced by the probing noise. Two simulations are presented to verify the feasibility and effectiveness of the proposed algorithm.     

Resistin is elevated in cystic fibrosis sputum and correlates negatively with lung function

Background

Resistin is an immunometabolic mediator that is elevated in several inflammatory disorders. A ligand for Toll-like receptor 4, resistin modulates the recruitment and activation of myeloid cells, notably neutrophils. Neutrophils are major drivers of cystic fibrosis (CF) lung disease, in part due to the release of human neutrophil elastase- and myeloperoxidase-rich primary granules, leading to tissue damage. Here we assessed the relationship of resistin to CF lung disease.

Uncertainty evaluation at three spatial scales for the NDVI-based VWC estimation method used in the SMAP algorithm

Vegetation water content (VWC) is the key input parameter for a soil moisture retrieval algorithm based on microwave remote sensing, and VWC uncertainty can limit the estimated accuracy of soil moisture. There has been little research on VWC algorithm development and validation in China, and the uncertainty of the VWC estimation method has not been well evaluated. Therefore, the aim of this study is to evaluate the uncertainty of the VWC estimation method used in the SMAP (Soil Moisture Active Passive) algorithm on three spatial scales (the point-scale, 30 m scale, and 1 km scale) for maize in northeast China. Results from three ground experimental datasets showed that the SMAP VWC estimation method was strongly biased with an average overestimation of 1.16 kg m^?2,1.04 kg m^?2, and 1.13 kg m^?2 for the point-scale, 30 m scale, and 1 km scale respectively, and maximum bias occurred in the mid-stage of maize. Also, a new power relationship between NDVI (Normalized Difference Vegetation Index) and VWC was proposed for the 30 m scale based on Sentinel 2 NDVI and field VWC values from 2017 experiment, with respective R² (coefficient of determination) and Root Mean Squared Error (RMSE) values of 0.80 and 0.67 kg m^?2. The results confirmed that this power relationship was still suitable for VWC estimation at the 1 km scale, and it has smaller bias than the original SMAP VWC method. Future work will be carried out to evaluate the applicability of this VWC estimation method over a lager region. It is expected that it can improve the accuracy of soil moisture by providing high precision VWC input parameters.     

腹膜前引流对腹腔镜经腹腹膜前疝修补术患者术后血肿及血清肿的影响

目的探讨腹腔镜经腹腹膜前疝修补术（TAPP）放置腹膜前引流对术后血肿及血清肿的影响。 方法选取2016年6月至2018年5月，江苏省苏州市中西医结合医院收治的单侧腹股沟疝患者90例，随机分为试验组和对照组，2组患者均行TAPP手术。试验组放置腹膜前引流管，对照组不放置引流管。收集2组患者的一般资料、手术相关资料及随访资料进行统计学分析，对比2组患者术后血肿及血清肿发生率差异。 结果全部患者均完成手术及随访。2组患者的一般资料、疝位置、疝分型、手术时间、住院花费、术后住院时间差异无统计学意义（P>0.05）。2组患者的术后发热发生率、急性疼痛发生率差异无统计学意义（P>0.05）。试验组术后血肿发生率明显低于对照组（P<0.05），试验组患者术后1和3个月血清肿发生率明显低于对照组，差异有统计学意义（P<0.05）。2组患者1年随访均观察到1例复发的病例，差异无统计学意义（P>0.05）；随访期内2组患者均未出现感染的病例。 结论TAPP中，放置腹膜前引流管能够有效降低患者术后血肿和血清肿的发生率，同时并不增加感染和复发风险。