Yijie Zhang

Respiration is a critical physiological signal, and abnormal respiratory patterns are widely recognized as key indicators of various cardiopulmonary and neurological disorders, making continuous monitoring crucial. However, existing clinical systems are constrained by motion limitations, complexity, and cost, hindering daily use. In this work, we present a bio-inspired, low-cost, flexible, and self-powered respiration sensor (BLFS-RS) inspired by the fish lateral line system, operating via contact electrification and electrostatic induction. It features a semicylindrical structure made of silicone rubber, incorporating bionic air channels and a porous-villus composite microstructure. It detects respiratory forces by deforming with abdominal cavity fluctuations, enabling respiration monitoring. Experimental results show that the incorporation of the porous-villus structure increases the sensor’s peak output voltage by 556% compared to a nonstructured counterpart. Additionally, the BLFS-RS exhibits high sensitivity (0.88 V/kPa), high durability (300,000 cycles), and fast response time (48 ms). A wearable real-time respiratory monitoring system based on BLFS-RS enables the acquisition of a comprehensive range of human respiratory parameters, including respiratory rate, apnea–hypopnea index, and peak expiratory flow. Furthermore, patients suffering from speech impairments can utilize the BLFS-RS for alternative communication by encoding information through distinct respiratory patterns. This work is expected to provide a viable and sustainable solution for personalized healthcare and remote respiratory monitoring.

Supply chain coordination has been a research hot spot in supply chain management. This paper constructs a secondary supply chain system. Taking the abatement of the bullwhip effect and the double marginal effect as the coordination objective, a simulation study of supply chain decision coordination was conducted using system dynamics. First, by controlling the lead time, it was found that in the decentralized decision-making model, the profit of the supplier and the whole supply chain increases with the shortening of the lead time, and vice versa for the retailer. In the centralized decision-making model with the addition of information sharing and contract, it was found that the retailer’s profit is consistent with the trend of the supplier and the supply chain as a whole, and the supplier’s profit is lower than that of decentralized decision making in the pre-cooperation period. In addition, it is also found that adjusting the contract parameters can effectively improve the situation. Finally, the above models were analyzed for supply chain coordination decisions based on two scenarios: “cooperative stability” or “balance of effects”.

The rapid increase in the proportion of the elderly population in China has increased the demand for aged services. It is a huge challenge for the Chinese government to establish the aged service system to meet such a large demand in a short time. In its 14th Five-Year Development plan, to promote a more rational allocation of health services, the Chinese government plans to build a health service system for the elderly. Based on the aged service resource allocation model established in the previous research, this paper proposes optimization measures and improves the model. The second-order matrix sensitivity analysis is performed on 30 parameters in the improved model, and the influence law of parameters on the whole system under a different amplitude of variation is explored. The results show that the disability rate of the elderly population, the service capacity of aged service institutions, per capita disposable income, and other factors have a great impact on the balance between the supply and demand of aged service resources. Therefore, when formulating policies related to the allocation of aged service resources, we can focus on improving the health level of the elderly, increasing the investment of social funds in aged service, and improving people’s consumption levels, so as to further improve the aged service system.

The current situation and future development of the supply and demand coupling coordination of elderly care service resources reflect the level of elderly care service resource allocation. Whether factors affecting its development can be found is the key to promote the accurate allocation of elderly care service. Based on the coupling coordination model, the supply and demand of elderly care service resources, the development circumstance and the spatio-temporal evolution of supply and demand coupling coordination are analyzed in this paper by using the data of the elderly care service resources in 31 regions and autonomous regions in China from 2010 to 2019. The result shows that there are regional differences in the development of supply and demand coupling coordination of elderly care service resources. The degree of supply and demand coupling coordination of elderly care service resources in the western and northern regions is lower than that in the eastern and southern regions. Although the level in most areas of supply and demand coupling coordination of elderly care service resources will improve in the future, there is still a gap from good coordination. In order to strengthen the supply of elderly care service resources, and promote the upgrade of the supply and demand of elderly care service resources, the government should start from the demand of the elderly to increase investment in infrastructure construction, investment in elderly care services resources, talent training and other aspects.

With the rapid growth of the elderly population of China in recent years, the service demands of older Chinese people continue to increase. The increasingly severe situation with respect to the elderly population is an important social problem that China will face for a long time into the future. It is urgent to solve the problem of how to scientifically carry out allocation planning of service resources for the aged and guide the effective supply of service resources. This paper analyzes the factors affecting service resources for the aged, divides China’s service resource supply and demand system into a supply subsystem, a demand subsystem, and a population and economy subsystem. Using system dynamics methods to analyze the causal relationship between variables and the state space method to build a mathematical model and perform simulation analysis, we research the the current situation of China’s service resources supply and demand balance for the aged. In addition, we put forward resource configuration optimization measures for the future allocation of service resources for the aged, providing a practical basis for future decision-making.

In this paper, focusing on the inconvenience of variable value PID based on manual parameter adjustment for the hydraulic drive unit (HDU) of a legged robot, a method employing double-layer back propagation (BP) neural networks for learning the law of PID control parameters is proposed. The first layer is used to learn the relationship between different control parameters and the control performance of the system under various working conditions. The second layer is used to study the relationship between the parameters of the working conditions and the optimizing control parameters under various working conditions. The effectiveness of the proposed control method was verified by simulation and experiment. The results showed that the proposed method can provide a theoretical and experimental basis for the selection of control parameters, and can be extended to similar controllers, therefore possessing engineering application value.

This paper focused on three application problems of the traditional Deep Deterministic Policy Gradient(DDPG) algorithm. That is, the agent exploration is insufficient, the neural network performance is unsatisfied, the agent output fluctuates greatly. In terms of agent exploration strategy, network training algorithm and overall algorithm implementation, an improved DDPG method based on double-layer BP neural network is proposed. This method introduces fuzzy algorithm and BFGS algorithm based on Armijo-Goldstein criterion, improves the exploration efficiency, learning efficiency and convergence of BP neural network, increases the number of layers of BP neural network to improve the fitting ability of the network, and adopts periodic update to ensure the stable operation of the algorithm. The experimental results show that the deep learning network based on the improved DDPG algorithm has greatly improved the performance compared with the traditional method after multiple rounds of self-learning under variable working conditions. This study lays a theoretical and experimental foundation for the extended application of deep learning algorithm.