Maintaining control performance in faulty control systems

Controller failures degrade a control system pedormance. In this paper, a novel main fenonce approach for controllerfailures is proposed fo restore fhe degraded peformance of the controller. The method is fo equivolenfly shifr any foulf occurring in a controller to the plant. Eased on the assumed process model, a compensafor with a serial link is designed to nlainfain the faulty controller in the SISO and MMO control systems. Several simulafioir results are given fo illustrate the procedure of using the metho

Fault detection in model predictive controller

Real-time monitoring and maintaining model predictive controller (MPC) is becoming an important issue with its wide implementation in the industries. In this paper, a measure is proposed to detect faults in MPCs by comparing the performance of the actual 'controller with the pedormance of the ideal controller. The ideal controller is derived from the dynamic matrix control @MC) in an ideal work situation and treated as a measure benchmark. A detection index based on the comparison is proposed to detect the state change of the target controller. This measure is illustrated through the implementation for a water tank process

Remote maintenance of control system performance over the internet

The Internet provides a significant benefit for the remote maintenance and fault diagnosis of various devices and plants. One such example is the UK’s distributed aircraft maintenance environment (DAME) (www.cs.york.ac.uk/dame), which provides a genetic test bed for distributed diagnostics based on Grid-enabled technologies. This paper focuses on developing a systematic method for the design of such a remote maintenance systems specifically for process control systems. Design issues of Internet-based remote maintenance systems for process control such as that proposed here include control performance assessment, fault detection, control performance maintenance, and heterogeneous data transfer over the Internet. A back-end and front-end architecture is proposed, in which all the heavy calculations are carried out locally. Light data and the characteristics of any heavy data are sent to the front-end located on the remote server for consideration by remote experts. The remote maintenance system is illustrated by reference to the implementation in a process control rig

Reference model based maintenance of control system performance for industrial processes

In the last decade, fault tolerant controls (FTC) have enjoyed tremendous success to effectively accommodate defects in sensors, actuators, or plants. However, little of them considered what should be done once a control system performance is degraded during the operation. The aim of this paper is to maintain the performance of a control system at an acceptable level based on a pre-defined reference model. A maintenance approach is proposed and experimented in this paper. The method is to insert a compensator into the faulty control system and make the compensator and the faulty open loop system working together to track the pre-defined reference model. The proposed method is illustrated by reference to a mini process rig and shows the potential to industrial processes

Reference Model Based Maintenance of Control System Performance for Industrial Processes

In the last decade, fault tolerant controls (FTC) have enjoyed tremendous success to effectively accommodate defects in sensors, actuators, or plants. However, little of them considered what should be done once a control system performance is degraded during the operation. The aim of this paper is to maintain the performance of a control system at an acceptable level based on a pre-defined reference model. A maintenance approach is proposed and experimented in this paper. The method is to insert a compensator into the faulty control system and make the compensator and the faulty open loop system working together to track the pre-defined reference model. The proposed method is illustrated by reference to a mini process rig and shows the potential to industrial processes

Case report: A rare case of anomalous origin of the left coronary artery from the pulmonary artery accompanied with unilateral absence of pulmonary artery in an adult patient

Both the anomalous origin of the left coronary artery from the pulmonary artery (ALCAPA) and unilateral absence of the pulmonary artery (UAPA) are rare congenital malformations, ALCAPA accompanied with UAPA is extremely rare. Here, we reported a middle-aged man admitted to our department for evaluation of chest pain during exercise. Physical examination and lab tests did not unveil obvious abnormality; however, transthoracic echocardiogram (TTE) revealed multivessel myocardial collateral blood flow signals in the left ventricular wall and ventricular septum, a shunting flow from the left coronary artery into the pulmonary artery and dilated right coronary artery (RCA), which supported but did not confirm the diagnosis of ALCAPA. Coronary angiography (CAG) showed an absent left coronary ostium and a dilated RCA, with extensive collaterals supplying the left coronary system. Multidetector computed tomography angiography (MDCTA) was then performed and revealed the anomalous origin of the left main coronary artery (LMCA) arising from the pulmonary artery, and it incidentally unveiled another rare congenital malformation of UAPA. The patient underwent surgical correction of ALCAPA by reimplantation of the LMCA to the aorta, without surgical treatment of UAPA. The patient had been in good clinical condition and remained angina free with good exercise tolerance during follow-up (∼6 months so far). In this case, we discussed the diagnostic value of TTE, CAG, and MDCTA on rare abnormalities as ALCAPA and UAPA. We highlighted the role of multiple non-invasive imaging modalities in diagnosing rare causes of angina in adult patients, and the importance of careful examination in avoiding misdiagnosis. To our best knowledge, this is the first report of ALCAPA accompanied with UAPA in an adult patient

Underlying beneficial effects of Rhubarb on constipation-induced inflammation, disorder of gut microbiome and metabolism

Background: Constipation is a common syndrome and a worldwide healthy problem. Constipation patients are becoming younger, with a 29.6% overall prevalence in children, which has captured significant attention because of its epigenetic rejuvenation and recurrent episodes. Despite the usage of rhubarb extract to relieve constipation, novel targets and genes implicated in target-relevant pathways with remarkable functionalities should still be sought for.Materials and methods: We established a reliable constipation model in C57B/6N male mice using intragastric administration diphenoxylate, and the eligible subjects received 600 mg/25 g rhubarb extract to alleviate constipation. Resultant constipation was morphological and genetically compared with the specimen from different groups.Results: Constipation mice exhibited thicker muscle layers, higher levels of cytokines, including IL-17 and IL-23, and lower content of IL-22. Bacterial abundance and diversity varied tremendously. Notably, the alterations were reversed following rhubarb extract treatment. Additionally, Constipation also had a substantial impact on short-chain fatty acids (SCFAs), medium- and long-chain fatty acids (MLCFAs), and the expression of SCFA receptors, GPR41 and GPR43.Conclusion: This thesis has provided insight that rhubarb extract promoted the flexibility of collagen fiber, reduced pro-inflammatory cytokines, enhanced anti-inflammatory cytokines, and maintained gut microflora balance with potential impacts on the fatty acid and polyamine metabolism

The Ninth Visual Object Tracking VOT2021 Challenge Results

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An approach for controller fault detection

Monitoring and maintaining of control software becomes more and more important and difficult with the increase of control software in size and complexity. In this paper, an approach for control software fault detection is proposed, which is based on the monitoring of the discrepancies between the control outputs of the actual controller and the benchmark controller, a Linear Quadratic Gaussian (LQG) controller. The discrepancies are assumed to be Gaussian distribution with a stable mean under the normal situation. Faults in the actual controller are characterized by sudden jumps in the mean of the discrepancies. The fault detection is transferred into a jump point identification problem. A detector based on Generalized Likelihood Ratio (GLR) test is employed for the jump point identification. The proposed approach is applicable to general control software even it is only illustrated through a water heater case study with a simple PID controller