Multihop Clustering Routing Protocol Based on Improved Coronavirus Herd Immunity Optimizer and Q-Learning in WSNs

Wireless sensor networks (WSNs) are composed of a large number of spatially distributed sensor nodes to monitor and transmit information from the environment. However, the batteries used by these sensor nodes have limited energy and cannot be charged or replaced due to the harsh deployment environment. This energy limitation will seriously affect the lifetime of the network. Therefore, the purpose of this research is to reduce energy consumption and balance the load of sensor nodes by clustering routing protocols, so as to prolong the lifetime of the network. First, the coronavirus herd immune optimizer is improved and used to optimize the network clustering. Second, the cluster heads (CHs) are selected according to the energy and location factors in the clusters, and a reasonable CH replacement mechanism is designed to avoid the extra communication energy consumption caused by the frequent replacement of CHs. Finally, a multihop routing mechanism between the CHs and the base station is constructed by Q-learning. Simulation results show that the proposed work can improve the structure of clusters, enhance the load balance of nodes, reduce network energy consumption, and prolong the network lifetime. The appearance time of the first energy-depleted node is delayed by 25.8%, 85.9%, and 162.2% compared with IGWO, ACA-LEACH, and DEAL in the monitoring area of $300×300 m, respectively. In addition, the proposed protocol shows better adaptability in varying dynamic conditions. © 2001-2012 IEEE.

Does Bike Sharing increase House Prices? Evidence from Micro-level Data and the Impact of COVID-19

With unique datasets, this paper studies the effects of dockless bike sharing on house prices. We find that in neighborhoods relatively far from subway stations, house prices increase with the usage intensity of shared bikes. This indicates a positive value of bike sharing as a complement to the subway network. Meanwhile, shared bike usage intensity also has a negative impact on house prices. The negative effect is mitigated for luxury neighborhoods and neighborhoods near City Management Teams, suggesting that the negative effect is related to bike misplacement. Since the breakout of COVID-19, both the positive and negative price impacts have become more evident. This is consistent with the fact that the user base of shared bikes, which allow for social distancing in an open space, has increased during the pandemic. This may enhance people's confidence in the long survival of the bike sharing industry.

[Comparison of severity classification of Chinese protocol, pneumonia severity index and CURB-65 in risk stratification and prognostic assessment of coronavirus disease 2019].

Objective: To investigate the application of severity classification according to the protocol on the Diagnosis and Treatment of coronavirus disease 2019(COVID-19)by the National Health Commission of China, pneumonia severity index(PSI) and CURB-65　in risk stratification and prognostic assessment of COVID-19. Methods: Clinical data of 234 in-hospital patients with COVID-19 were collected and retrospectively reviewed in Wuhan Tongji Hospital. Patients were divided into 3 groups (common, severe, and critical type) at admission according to the sixth version of the protocol issued by the National Health Commission of China on Diagnosis and Treatment of COVID-19. At the same time, the severity of pneumonia was calculated by PSI and CURB-65, and the patients were stratified into 3 risk groups, namely mild, moderate, and severe groups. The hospital mortality rate was evaluated in each group. Sensitivity, specificity, positive predictive values, negative predictive values, and the area under the receiver operating characteristic(ROC) curve(AUC) for predicting hospital mortality in each rule were assessed. Results: According to the severity classification of Chinese protocol, the proportion of patients with common type, severe type, and the critical type was 15.8%, 75.6%, and 8.5%, respectively. No in-hospital death occurred in the common type. As for PSI and CURB-65, greater proportions of patients were classified as low risk(79.1% and 75.6%, respectively), while smaller proportions of patients were classified as moderate and high risk(16.2%, 15.0%; 4.7%, 9.4%, respectively). In-hospital death occurred in low and moderate risk patients identified by these 2 scoring systems. The mortality of the critical group of the Chinese protocol was 65%, and the sensitivity and specificity of predicting in-hospital mortality were 36.4% and 97.0%, respectively. The mortality in the high risk group of PSI and CURB-65 was 100% and 77.3%. The risk class V of PSI and CURB-65 score 3-5 had high specificity(100% and 97.4%, respectively)but low sensitivity(33.3% and 51.5%, respectively)in predicting in-hospital mortality. The AUC of the Chinese protocol severity classification, PSI, and CURB-65 was 0.735, 0.951, and 0.912. The optimal cut-off point of PSI was risk class Ⅳ, and the sensitivity and specificity for predicting mortality were 90.9% and 90.5%. The optimal cut-off point of CURB-65 was score 2, and the corresponding sensitivity and specificity were 84.8% and 85.6%. Conclusions: PSI and CURB-65 can be used for risk stratification and prognostic assessment in patients with COVID-19.

[Thoughts and practice on the treatment of severe and critical new coronavirus pneumonia].

Severe and critical coronavirus pneumonia 2019 (COVID-19) often occurs in elder patients with multiple comorbidities, and severe hypoxemia events constitute a key factor for the deterioration of some cases. The critical type of COVID-19 could progress into acute respiratory distress syndrome and multi-organ dysfunction, which are the major causes of death. Early non-invasive ventilation (NIV) treatment of possible pathophysiological abnormalities is helpful to improve prognosis. Close monitoring of oxygenation, reducing patients' oxygen consumption, active psychological intervention, and rapid handling of severe hypoxemia events are the key factors for successful NIV treatment. In addition, active adjuvant therapies such as correcting coagulation dysfunction, providing proper nutritional support, accurate volume control, and safe individualized blood glucose monitoring are of great significance.