Recently, the compound element pseudo transient analysis, CEPTA, method is regarded as an efficient practical method to find DC operating points of nonlinear circuits when the Newton-Raphson method fails. In the previous CEPTA method, an effective SPICE3 implementation algorithm was proposed without expanding the Jacobian matrix. However the limitation of step size was not well considered. Thus, the non-convergence problem occurs and the simulation efficiency is still a big challenge for current LSI nonlinear cicuits, especially for some practical large-scale circuits. Therefore, in this paper, we propose a new SPICE3 implementation algorithm and an embedding algorithm, which is where to insert the pseudo capacitors, for the CEPTA method. The proposed implementation algorithm has no limitation for step size and can significantly improve simulation efficiency. Considering the existence of various types of circuits, we extend some possible embedding positions. Numerical examples demonstrate the improvement of simulation efficiency and convergence performance.
The bridge crane system is widely used in the industrial production for transporting large loads. Its anti-sway positioning control is quite crucial for enhancing handling efficiency and safety, but it is also difficult due to underactuated dynamics and various disturbances. In this paper, an anti-sway positioning control algorithm for unmanned crane is proposed based on the load generalized position tracking control algorithm (GPTC), which combines with a disturbance observer to effectively reject the lumped disturbances. The test results show that the proposed method can effectively achieve anti-sway and positioning with prominent disturbance suppression improvements.
Finding DC operating points of nonlinear circuits is an important and difficult task. The Newton-Raphson method adopted in the SPICE-like simulators often fails to converge to a solution. To overcome this convergence problem, homotopy methods have been studied from various viewpoints. However, the previous studies are mainly focused on the bipolar transistor circuits. Also the efficiencies of the previous homotopy methods for MOS transistor circuits are not satisfactory. Therefore, finding a more efficient homotopy method for MOS transistor circuits becomes necessary and important. This paper proposes a Newton fixed-point homotopy method for MOS transistor circuits and proposes an embedding algorithm in the implementation as well. Moreover, the global convergence theorems of the proposed Newton fixed-point homotopy method for MOS transistor circuits are also proved. Numerical examples show that the efficiencies for finding DC operating points of MOS transistor circuits by the proposed MOS Newton fixed-point homotopy method with the two embedding types can be largely enhanced (can larger than 50%) comparing with the conventional MOS homotopy methods, especially for some large-scale MOS transistor circuits which can not be easily solved by the SPICE3 and HSPICE simulators.
In the hydraulic classification process, precise control for the flow rate of overflow water is vital to guarantee the uniformity and stability of the powder product size. Usually the multiple overflow tanks are supplied by a shared overflow pipeline, which gives rise to large coupling effect in the control of the flow rates of multiple overflow tanks simultaneously. To solve this issue, it is necessary to keep the water pressure in the shared overflow pipeline constant accurately. However, it is not easy due to strong disturbances. Several control strategies have been proposed to control the water pressure. Most of them (such as PID and MPC) reject disturbances merely through feedback regulation and do not deal with disturbances directly. This may cause great performance degradation when strong disturbances occur. To improve the disturbance rejection performance, a control scheme based on PID and disturbance observer was proposed in this paper. The scheme combines a feedforward compensation part using disturbance observer and a feedback regulation part using PID. The test results illustrate that the proposed method can remarkably improve the disturbance attenuation property compared with the conventional PID method in the hydraulic classification process.
Recently, the pseudo-transient analysis (PTA) methods have been researched as one of the most effective continuation methods to overcome the non-convergence problem of the Newton-Raphson method for finding the DC operating points of nonlinear circuits. However, the former PTA methods have a time-consuming problem, especially for some large-scale circuits. In this paper, we combine an effective ramping algorithm with two proposed ramping functions and the damped PTA (DPTA) algorithm together to improve the simulation efficiency. It can eliminate the oscillation and time-consuming problems at the same time. Besides, a restart method in the SPICE3 implementation is also proposed, which is effectively to improve convergence when the circuit is stuck in an infinite loop and fails to converge during the simulation. Numerical examples demonstrate the efficiency and convergence improvement of the proposed algorithms.
Proprotein convertase subtilisin/kexin type 9 (PCSK9) inhibitors, a novel class of cholesterol-lowering drugs, can reduce atherosclerosis independent of systemic lipid changes. However, the mechanism by which PCSK9 inhibition protects against arteriosclerosis has not been fully elucidated. Recent evidence has demonstrated a correlation between PCSK9 inhibitors and oxidative stress, which accelerates atherosclerotic development. Moreover, an increasing number of studies have shown that autophagy protects the vasculature against atherosclerosis. Therefore, the aims of this study were to investigate the effect of PCSK9 inhibition on oxidative stress and autophagy in atherosclerosis and determine whether autophagy regulates PCSK9 inhibition-mediated oxidative stress and inflammation in macrophages.Male apolipoprotein E (ApoE)-/- mice were fed a high-fat diet (HFD) for 8 weeks and then received the PCSK9 inhibitor (evolocumab), vehicle, or evolocumab plus chloroquine (CQ) for another 8 weeks. ApoE-/- mice in the control group were fed a regular (i.e., non-high-fat) diet for 16 weeks. Additional in vitro experiments were performed in oxidized low-density lipoprotein (ox-LDL)-treated human acute monocytic leukemia cell line THP-1-derived macrophages to mimic the pathophysiologic process of atherosclerosis.PCSK9 inhibitor treatment reduced oxidative stress, lipid deposition, and plaque lesion area and induced autophagy in HFD-fed ApoE-/- mice. Most importantly, the administration of chloroquine (CQ), an autophagy inhibitor, significantly reduced the beneficial effects of PCSK9-inhibitor treatment on oxidative stress, lipid accumulation, inflammation, and atherosclerotic lesions in HFD-fed ApoE-/- mice. The in vitro experiments further showed that the PCSK9 inhibitor enhanced autophagic flux in ox-LDL-treated THP-1-derived macrophages, as indicated by increases in the numbers of autophagosomes and autolysosomes. Moreover, the autophagy inhibitor CQ also reduced PCSK9 inhibition-mediated protection against oxidative stress, generation of reactive oxygen species (ROS) and inflammation in ox-LDL-treated THP-1-derived macrophages.This study reveals a novel protective mechanism by which PCSK9 inhibition enhances autophagy and thereby reduces oxidative stress and inflammation in atherosclerosis.
With the rapid development of the stereo garage, there are plenty of security problems appeared in stereo garage. The monitoring and management system of the stereo garage has attracted more and more attention. A cloud monitoring and management system for stereo garage is designed based on Web technology, which collects real-time data from the intelligent controller of the stereo garage, stores them in the cloud database. History and real-time data are studied to complete the functions of garage overview, real-time video monitoring, fault management, garage management, and system management. Deep confidence networks are proposed to conduct fault diagnosis for stereo garage, and the results are sent to the management interface of cloud portal (APP and website) for remote management. Test results show that the management efficiency of the stereo garage is significantly improved. The system guarantees the safe and reliable work of the stereo garage. It achieves better performance especially in the remote management and fault diagnosis.
The recognition of steel coils and saddles from the point cloud data is quite important in complex steel industrial environment. In this work, a deep learning algorithm based on multi-scale features and Pointnet network is proposed. For the preprocessing of raw data, the pass-through filtering method and Ransac algorithm are designed to filter and remove uninteresting point clouds, and then the edge-detection algorithm and MeanShift clustering method are added to segment and obtain valid single point cloud data. Next, an improved Pointnet network is proposed to classify the type of coils and saddles, where a multiscale features' extraction is introduced to enhance the capability of extracting partial point information. At last, 4500 datasets of steel coils\saddles collected from on-site industry are used for network training. The experimental results demonstrated that the method can achieve high recognition accuracy and meet the real-time requirements.
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