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Abstract The growth of marine resources exploitation has led to increased research interest in electro‐hydraulic systems for marine simulation. This study proposes a proportional plus resonant (PR) controller to achieve high tracking performance for electro‐hydraulic systems. Due to the complex structure and non‐linear flow dynamics, establishing accurate mathematical models of electro‐hydraulic systems is challenging. The local linearization technique is applied to simplify the process of model establishment. The system gain is limited by the stability margin due to the input delay, resulting in a phase delay between the real trajectory and the desired reference. To compensate for the phase delay in tracking periodic reference with the traditional proportional and integral controller, a resonant item is added into the controller. The stability analysis of the closed‐loop system is performed using Routh‐Hurwitz criterion. Furthermore, the controller parameters are tuned based on the frequency characteristic to achieve high tracking performance and maintain the adequate stability margin. The effectiveness of the proposed PR controller in tracking periodic references is validated through numerical simulations and practical experiments.

Abstract The monitoring and control of DC-DC converters have become key issues since DC-DC converters are gradually playing increasingly crucial roles in power electronics applications such as electric vehicles and renewable energy systems. As an emerging and transforming technology, the digital twin, which is a dynamic virtual replica of a physical system, can potentially provide solutions for the monitoring and control of DC-DC converters. This work discusses the design and implementation of the digital twin DC-DC converter in detail. The key features of the physical and twin systems are outlined, and the control architecture is provided. To verify the effectiveness of the proposed digital twin method, four possible cases that may occur during the practical control scenarios of DC-DC converter applications are discussed. Simulations and experimental verification are conducted, showing that the digital twin can dynamically track the physical DC-DC converter, detect the failure of the physical controller and replace it in real time.

Truck hoisting detection constitutes a key focus in port security, for which no optimal resolution has been identified. To address the issues of high costs, susceptibility to weather conditions, and low accuracy in conventional methods for truck hoisting detection, a non-intrusive detection approach is proposed in this paper. The proposed approach utilizes a mathematical model and an extreme gradient boosting (XGBoost) model. Electrical signals, including voltage and current, collected by Hall sensors are processed by the mathematical model, which augments their physical information. Subsequently, the dataset filtered by the mathematical model is used to train the XGBoost model, enabling the XGBoost model to effectively identify abnormal hoists. Improvements were observed in the performance of the XGBoost model as utilized in this paper. Finally, experiments were conducted at several stations. The overall false positive rate did not exceed 0.7% and no false negatives occurred in the experiments. The experimental results demonstrated the excellent performance of the proposed approach, which can reduce the costs and improve the accuracy of detection in container hoisting.

Abstract Background Metal(loid)s can promote the spread and enrichment of antibiotic resistance genes (ARGs) in the environment through a co-selection effect. However, it remains unclear whether exposure of microorganisms to varying concentrations of selenium (Se), an essential but potentially deleterious metal(loid) to living organisms, can influence the migration and distribution of ARGs in forest soils. Results Precisely 235 ARGs conferring resistance to seven classes of antibiotics were detected along a Se gradient (0.06–20.65 mg kg−1) across 24 forest soils. (flor)/(chlor)/(am)phenicol resistance genes were the most abundant in all samples. The total abundance of ARGs first increased and then decreased with an elevated available Se content threshold of 0.034 mg kg−1 (P = 2E−05). A structural equation model revealed that the dominant mechanism through which Se indirectly influences the vertical migration of ARGs is by regulating the abundance of the bacterial community. In addition, the methylation of Se (mediated by tehB) and the repairing of DNA damages (mediated by ruvB and recG) were the dominant mechanisms involved in Se resistance in the forest soils. The co-occurrence network analysis revealed a significant correlated cluster between Se-resistance genes, MGEs and ARGs, suggesting the co-transfer potential. Lelliottia amnigena YTB01 isolated from the soil was able to tolerate 50 μg mL−1 ampicillin and 1000 mg kg−1 sodium selenite, and harbored both Se resistant genes and ARGs in the genome. Conclusions Our study demonstrated that the spread and enrichment of ARGs are enhanced under moderate Se pressure but inhibited under severe Se pressure in the forest soil (threshold at 0.034 mg kg−1 available Se content). The data generated in this pilot study points to the potential health risk associated with Se contamination and its associated influence on ARGs distribution in soil.

Abstract Online experimental systems that include remote and virtual experiments based on the Internet has become a new form of experiment in engineering education. This paper proposes a virtual experiment for the complex process control system. It is based on the networked control system laboratory (NCSLab), which provides a reliable framework for virtual thermal experiment. Taking the combustion system of 1000 MW ultra‐supercritical coal‐fired once‐through boiler‐turbine units as an example, the framework and the implementation process of the online system are given in this paper. A new presentation form for complex processes control experiment is provided, which could be a solution for simulating physical experimental equipment in virtual environments. The potential danger in practical experiments could be avoided. Additionally, the real‐time operation for complex control systems could be presented in a 3D scene. Meanwhile, the flexibility and efficiency could be increased in engineering experimental education. Moreover, using the experiment evaluation method, the references and feedback for teaching and assessment are provided in this paper.

Universality is crucial for systems to provide services to users with different backgrounds. A good language system can remove language barriers to help to improve system universality. To improve user experience and provide new features to users, the Networked Control System Laboratory (NCSLab) has been redeveloped based on React. To achieve toward an international platform, this paper introduces a web-based multi-language system for remote and virtual laboratories based on React. The language system is implemented based on an open source tool named react-intl-universal. The architecture and modular design concept of the language system are investigated and the design and implementation are explored in detail from the perspective of the front-end and back-end separation scheme. The proposed language system has been integrated into the new React-based NCSLab system, which is scalable and can improve universality to serve not only domestic users in China, but also international users from all over the world.

Abstract This paper investigates the composite hierarchical anti‐disturbance control problem for switched systems with saturating inputs, in which the multiple disturbances including normal‐bounded disturbances, white noises and nonlinear uncertainties are considered. According to whether the states of the system be available or not, two types of disturbance observers and a state observer are designed, respectively. With the values of the observers, the observer‐based composite controllers are constructed accordingly, under which an uniform form of the closed‐loop system is presented. By utilising the minimum dwell‐time technique and stochastic control theory, a new criterion of the mean‐square exponential stability is presented for the closed‐loop system with a weighted H∞ performance level. The design conditions of the observers for the disturbances generated by exosystem and states of the system are proposed by propositions, respectively. Based on the gains of the observers, the solvable synthesis conditions of the composite controllers are presented for the cases of the available and unavailable states of the system. The simulations of GE‐90 aero‐engine model and a numerical example are employed to verify the applicability of the obtained results.

In this paper, the optimal control method is used to discuss the advertising investment decisions for the consignment platform, where the delayed effect of the advertising is introduced to reflect the dynamics of platform goodwill. Firstly, the optimal advertising investment policies are obtained in the integrated and decentralized decision strictures by applying the optimal control theory. Besides, the comparisons of the optimal profits are provided in two decision strictures. Our results suggest that the centralization leads to higher channel performance only when time delay is below a certain threshold. Secondly, a consignment contract with the bilateral participation and the constant platform use fees is proposed to coordinate the decentralized system. Finally, some simulations are employed to obtain more management insights and to illustrate the coordination capability of the proposed contract.

Here in we report a case of acute liver failure with hepatic infarction after transjugular intrahepatic portosystemic shunt (TIPS). An upper gastrointestinal hemorrhage patient with a medical history of alcoholic cirrhosis underwent a TIPS procedure. One day after TIPS, his alanine aminotransferase and aspartate aminotransferase levels increased to 1214 U/L and 1511 U/L, respectively. Two days after TIPS, they peaked at alanine aminotransferase 8389 U/L and aspartate aminotransferase >7500 U/L, respectively. An emergent stent occlusion was performed on the second day. Portography showed that there were no portal vein branches or parenchymal stains on the edge of the right liver lobe. A CT scan demonstrated diffuse hepatic parenchyma, homogeneous hypodense lesion, and bilateral pleural effusion. The patient died of liver failure and multiple organ dysfunction syndrome 6 hours after the stent occlusion. Keywords: Transjugular intrahepatic portosystemic shunt, Hepatic infarction, liver failure

In this paper, the external consensus problem is discussed for networked multiagent systems with communication delays under an event-triggered mechanism. The communication topology among agents is characterized by an undirected and connected graph, and there exist network-induced delays during data transmissions. Based on recursive equations, a prediction strategy is proposed to actively compensate for the effects of network-induced delays. Then, an event-triggered mechanism is introduced to avoid continuous control updates and continuous communication among agents. According to the above prediction strategy and event-triggered mechanism, a distributed external consensus control protocol is proposed, by which system stability is ensured and the external consensus can be achieved. Finally, numerical simulation is made to illustrate the validity of the proposed protocol.

This paper studies the problem of disturbance attenuation and rejection for switched systems with nonlinear uncertainty and input saturation via composite anti-disturbance control technique, in which the exosystem-generated disturbance and H2-norm-bounded disturbance are considered. For switched systems, the switching law and input saturation increase the difficulty for the design of the disturbance observer and the composite control scheme. A switching disturbance observer is designed to obtain the estimation of the matched disturbance, and a novel switching composite controller is further constructed based on the estimated value. By proposing a state-dependent switching law and utilizing the multiple Lyapunov function technology, the criteria are presented to ensure the local asymptotic stability with an H∞ performance level for the closed-loop system. Furthermore, two optimal algorithms of the design of the controller are put forward to maximize the estimation of the domain of attraction of the closed-loop and the upper bound on the H2-norm of the disturbance, respectively. The effectiveness of the proposed technique is illustrated via the numerical examples.

Abstract Background Despite its rarity, studies have shown the incidence of gastric neuroendocrine tumors (G‐NETs) is increasing. This study investigated the risk factors affecting the survival of G‐NETs patients and their prognosis over time. Method A retrospective analysis of 506 G‐NETs patients who underwent surgery for nonmetastatic disease from the Surveillance, Epidemiology and End Result database from 1988 to 2011 was conducted. Multivariate Cox regression analyses identified the prognostic factors affecting overall survival (OS) and disease‐specific survival (DSS). Three‐year conditional survival (COS3 and CDS3) estimates at “x” year after treatment were calculated as follows: COS3 = OS(x + 3)/OS(x) and CDS3 = DSS(x + 3)/DSS(x). Results The 1‐, 3‐, and 5‐year OS rates of all patients after surgery were 90.2%, 77.3%, and 68.8%, respectively. The 1‐, 3‐, and 5‐year DSS rates after surgery were 93.9%, 84.5%, and 80.9%, respectively. In the multivariate analysis, age, tumor grade, and T stage were independent prognostic factors of OS and DSS (all P

Fast and strong interacting systems are hard to control from both performance and control effort points of view. Moreover, multiple objective functions or objectives with various identifiers of varying weights can hold unfeasible solutions at times. A novel cost objective function is proposed here to overcome both feasibility set limitations and computational burdens. An application example is used to illustrate its added value, which is a fast and strong interacting multivariable system: a landscape office lighting regulatory problem. New lighting technology and an intelligent control system have been produced to improve control accuracy and reduce power consumption. While optimizing the hardware of the lighting system, the energy consumption can be further reduced by applying advanced control strategy in the lighting system. This paper designed a fractional order distributed model predictive control (FOMPC) scheme to realize the reference tracking and stability control of multiple illuminations at the same time. In order to test the efficiency of the control strategy, an experiment was carried out on the lighting setup based on the dSPACE control system. The FOMPC scheme was analyzed through simulation and lighting experiments based on the dSPACE control system. Through a comparison with the mode predictive control (MPC) scheme, the superiority of the FOMPC scheme for the dynamic behavior and control performance of multiple lighting systems was verified. The research results provide a basis for multiple lighting control and its application.

In this article, the coordinated path-following control problem for networked unmanned surface vehicles is investigated. The communication network brings time delays and packet dropouts to the fleet, which will have negative effects on the control performance of the fleet. To attenuate the negative effects, a novel networked predictive control scheme is proposed. By introducing the predictive error into the control scheme, the proposed control strategy admits some advantages compared with existing networked predictive control strategies, for example, a degree of robustness to disturbances, lower requirements for the computing capacity of the onboard processors, high flexibility in controller design, and so on. Conditions that guarantee the control performance of the overall system are derived in the theoretical analysis. At last, experiments on hovercraft test beds are implemented to verify the effectiveness of the proposed control scheme.

This paper presents an innovative electronic magnetic geared (EMG) motor. The motor is designed and tested. This electronic EMG motor assembles parallel, serial or hybrid connections of stator windings into gears to accommodate the different speed and torque demands in the drive cycle. The objective of EMG is to increase the maximum speed and maximum torque range of the motor. A 1.5 kW prototype EMG motor was built up and tested on a test rig. The test results prove that the theory of EMG is correct. It will have a large positive impact on the energy efficiency of electric vehicles.

Online laboratories have been widely used in education, research, and industrial applications. For online laboratories, various architectures have been constructed to provide good user experience and powerful capabilities for online experimentation, in which the controller is a crucial part to connect the server with a controlled test rig. Regarding the physical nature of the controllers and test rigs used in online laboratories, a specific control process can be called a simulation, hardware-in-the-loop, rapid control prototyping, or physical control. This article presents an overview of the most commonly used controllers in current online laboratories, focusing on the functionalities, use purposes, and types of different controllers, as well as their role in online laboratories for teaching and learning. In particular, the low-cost PC controller used in the Networked Control System Laboratory, which provides both remote and virtual experiments, is introduced. The limitations and potential development directions of online laboratories are identified.

This paper describes the development and implementation of a robust high-accuracy ultrasonic indoor positioning system (UIPS). The UIPS consists of several wireless ultrasonic beacons in the indoor environment. Each of them has a fixed and known position coordinate and can collect all the transmissions from the target node or emit ultrasonic signals. Every wireless sensor network (WSN) node has two communication modules: one is WiFi, that transmits the data to the server, and the other is the radio frequency (RF) module, which is only used for time synchronization between different nodes, with accuracy up to 1 μs. The distance between the beacon and the target node is calculated by measuring the time-of-flight (TOF) for the ultrasonic signal, and then the position of the target is computed by some distances and the coordinate of the beacons. TOF estimation is the most important technique in the UIPS. A new time domain method to extract the envelope of the ultrasonic signals is presented in order to estimate the TOF. This method, with the envelope detection filter, estimates the value with the sampled values on both sides based on the least squares method (LSM). The simulation results show that the method can achieve envelope detection with a good filtering effect by means of the LSM. The highest precision and variance can reach 0.61 mm and 0.23 mm, respectively, in pseudo-range measurements with UIPS. A maximum location error of 10.2 mm is achieved in the positioning experiments for a moving robot, when UIPS works on the line-of-sight (LOS) signal.