Optimal Cooperative Secondary Control for Islanded DC Microgrids via a Fully Actuated Approach

DC-DC converter-based multi-bus DC microgrids(MGs) in series have received much attention, where the conflict between voltage recovery and current balancing has been a hot topic. The lack of models that accurately portray the electrical characteristics of actual MGs while is controller design-friendly has kept the issue active. To this end, this paper establishes a large-signal model containing the comprehensive dynamical behavior of the DC MGs based on the theory of high-order fully actuated systems, and proposes distributed optimal control based on this. The proposed secondary control method can achieve the two goals of voltage recovery and current sharing for multi-bus DC MGs. Additionally, the simple structure of the proposed approach is similar to one based on droop control, which allows this control technique to be easily implemented in a variety of modern microgrids with different configurations. In contrast to existing studies, the process of controller design in this paper is closely tied to the actual dynamics of the MGs. It is a prominent feature that enables engineers to customize the performance metrics of the system. In addition, the analysis of the stability of the closed-loop DC microgrid system, as well as the optimality and consensus of current sharing are given. Finally, a scaled-down solar and battery-based microgrid prototype with maximum power point tracking controller is developed in the laboratory to experimentally test the efficacy of the proposed control method.

Control Strategies for Digital Twin Systems

With the continuous breakthrough in information technology and its integration into practical applications, industrial digital twins are expected to accelerate their development in the near future. This paper studies various control strategies for digital twin systems from the viewpoint of practical applications.To make full use of advantages of digital twins for control systems, an architecture of digital twin control systems, adaptive model tracking scheme, performance prediction scheme, performance retention scheme, and fault tolerant control scheme are proposed. Those schemes are detailed to deal with different issues on model tracking, performance prediction, performance retention, and fault tolerant control of digital twin systems. Also, the stability of digital twin control systems is analysed. The proposed schemes for digital twin control systems are illustrated by examples.

Data-Driven Adaptive Predictive Control Method With Autotuned Weighting Factor for Nonlinear Systems Using Triangular Dynamic Linearization

Dear Editor,In this letter,a novel data-driven adaptive predictive control method is proposed using the triangular dynamic linearization technique.The proposed method only contains one time-varying parameter with explicit physical meaning,which can prevent severe deviation in parameter estimation.Specifically,a triangular dynamic linearization(TDL)data model is employed to predict future system outputs,and then to correct inaccurate predictive outputs,a feedback regulator is designed.An autotuned weighing factor is introduced to alleviate the computational burden in practical applications and further improve output tracking performance.Closed-loop stability conditions are derived by rigorous analysis.Simulation results are provided to demonstrate the efficacy of the proposed method.

Privacy-Preserving Consensus-Based Distributed Economic Dispatch of Smart Grids via State Decomposition

This paper studies the privacy-preserving distributed economic dispatch(DED)problem of smart grids.An autonomous consensus-based algorithm is developed via local data exchange with neighboring nodes,which covers both the islanded mode and the grid-connected mode of smart grids.To prevent power-sensitive information from being disclosed,a privacy-preserving mechanism is integrated into the proposed DED algorithm by randomly decomposing the state into two parts,where only partial data is transmitted.Our objective is to develop a privacy-preserving DED algorithm to achieve optimal power dispatch with the lowest generation cost under physical constraints while preventing sensitive information from being eavesdropped.To this end,a comprehensive analysis framework is established to ensure that the proposed algorithm can converge to the optimal solution of the concerned optimization problem by means of the consensus theory and the eigenvalue perturbation approach.In particular,the proposed autonomous algorithm can achieve a smooth transition between the islanded mode and the grid-connected mode.Furthermore,rigorous analysis is given to show privacy-preserving performance against internal and external eavesdroppers.Finally,case studies illustrate the feasibility and validity of the developed algorithm.

Disturbance Observer-Based Predictive Tracking Control of Uncertain HOFA Cyber-Physical Systems

Dear Editor,In this letter,an output tracking control problem of uncertain cyber-physical systems(CPSs)is considered in the perspective of high-order fully actuated(HOFA)system theory,where a lumped disturbance is used to denote the total uncertainties containing parameters perturbations and external disturbances.

上海市宝山区11~18岁青少年血压偏高现状及其与超重肥胖的关系

目的 了解上海市宝山区11~18岁青少年血压偏高现状及其与超重肥胖的关系,为预防青少年高血压提供参考依据。方法 利用2013—2019年上海市宝山区185 980名11~18岁青少年的体检数据,计算不同性别、年龄青少年的血压偏高率、超重率和肥胖率,采用Logistic回归分析血压偏高与超重肥胖的关系。结果 上海市宝山区11~18岁青少年收缩压(systolic blood pressure,SBP)和舒张压(diastolic blood pressure,DBP)均值分别为(112.77±13.86)mmHg与(67.72±9.51)mmHg,血压水平随年龄呈上升趋势;血压偏高检出率为18.49%,随年龄的增长而增长(χ^(2)=150.99,P <0.001)。男、女生血压偏高检出率分别为18.79%与18.16%(χ^(2)=12.05,P <0.01)。体重正常、超重、肥胖青少年血压偏高检出率分别为15.20%、23.45%、37.72%,不同体重指数(body mass index,BMI)组间差异有统计学意义(χ^(2)=5 809.51,P <0.001)。多元线性回归与Logistic回归分析显示,BMI与年龄是血压偏高的危险因素,15~18岁青少年血压偏高的风险是11~14岁青少年的1.13倍;超重和肥胖青少年血压偏高的风险分别为正常体重青少年的1.71倍和3.40倍(P <0.001)。结论 上海市宝山区11~18岁青少年血压偏高检出情况处于较高水平,超重肥胖和年龄是主要危险因素,控制青少年超重和肥胖能有效预防青少年血压偏高,应加强青少年血压监测与诊断。

Tracking Control of Multi-Agent Systems Using a Networked Predictive PID Tracking Scheme

With the rapid development of network technology and control technology,a networked multi-agent control system is a key direction of modern industrial control systems,such as industrial Internet systems.This paper studies the tracking control problem of networked multi-agent systems with communication constraints,where each agent has no information on the dynamics of other agents except their outputs.A networked predictive proportional integral derivative(PPID)tracking scheme is proposed to achieve the desired tracking performance,compensate actively for communication delays,and simplify implementation in a distributed manner.This scheme combines the past,present and predictive information of neighbour agents to form a tracking error signal for each agent,and applies the proportional,integral,and derivative of the agent tracking error signal to control each individual agent.The criteria of the stability and output tracking consensus of multi-agent systems with the networked PPID tracking scheme are derived through detailed analysis on the closed-loop systems.The effectiveness of the networked PPID tracking scheme is illustrated via an example.

Efficacy of different antibiotics in treatment of children with respiratory mycoplasma infection

BACKGROUND Respiratory infections in children are common pediatric diseases caused by pathogens that invade the respiratory system.Children are considerably susceptible to Mycoplasma pneumoniae infection.There has been widespread clinical attention on treatment strategies for this disease.AIM To analyze the clinical efficacy of different antibiotics in treating pediatric respiratory mycoplasma infections.METHODS We included 106 children with a confirmed diagnosis of respiratory mycoplasma infection who were admitted to our hospital from April 2017 to July 2019 and grouped them using a random number table.Among them,53 children each received clarithromycin or erythromycin.The clinical efficacy of both drugs was evaluated and compared.We performed the multiplex polymerase chain reaction(MP-PCR)test and determined the MP-PCR negative rate in children after the end of the treatment course.We compared the incidence of toxic and side effects,including nausea,diarrhea,and abdominal pain;further,we recorded the length of hospitalization,antipyretic time,and drug costs.Additionally,we evaluated and compared the compliance of the children during treatment.RESULTS The erythromycin group showed a significantly higher total effective rate of clinical treatment than the clarithromycin group.MP-PCR test results showed that the clarithromycin group had a significantly higher MP-PCR negative rate than the erythromycin group.Moreover,children in the clarithromycin group had shorter fever time,shorter hospital stays,and lower drug costs than those in the erythromycin group.The clarithromycin group had a significantly higher overall drug adherence rate than the erythromycin group.The incidence of toxic and side effects was significantly lower in the clarithromycin group than in the erythromycin group(P<0.05).CONCLUSION Our findings indicate that clarithromycin has various advantages over erythromycin,including higher application safety,stronger mycoplasma clearance,and higher medication compliance in children;therefore,it can be actively promoted.

Coordination of Networked Nonlinear Multi-Agents Using a High-Order Fully Actuated Predictive Control Strategy

This paper is concerned with the coordinative control problem of networked nonlinear multi-agents(NNM)with communication delays.A high-order fully actuated(HOFA)model is introduced to describe the nonlinear multi-agents.Based on this model,a HOFA predictive coordination method is proposed to compensate for the communication delays actively and achieve simultaneous stability and consensus.This method largely simplifies the design of networked nonlinear multi-agents and makes the control performance be same for networked nonlinear multi-agents with and without communication delays.The analysis on the closed-loop systems derives the simultaneous stability and consensus criteria of networked nonlinear multiagents using the HOFA predictive coordination method.With the presented way of designing HOFA predictive coordination controllers,a simulated example demonstrates the advantages of the proposed method.

经皮椎间孔镜联合经皮网袋成形技术治疗伴有神经根压迫症状的脊柱转移瘤

目的评估经皮椎间孔镜联合经皮网袋成形技术(PMCP)治疗腰椎单节段伴有神经根压迫症状的脊柱转移瘤的临床疗效及安全性。方法回顾性分析2012年9月-2016年12月应用经皮椎间孔镜联合PMCP治疗腰椎单节段伴有神经根压迫症状的脊柱转移瘤患者19例。观察手术时间、术中出血量和住院时间,采用视觉模拟评分(VAS)及MacNab标准评估手术疗效。按MacNab标准评定疗效优良率。结果患者手术时间(105.52±14.25)min、术中出血量(35.58±6.76)ml、住院时间(8.25±2.14)d,术后第3天VAS评分(3.18±1.96)分、术后第3个月VAS评分与术前相比[(1.67±1.05)和(8.45±1.35)分],差异均具有统计学意义(P <0.05);按MacNab标准评定疗效优良率为84.21%。结论经皮椎间孔镜联合PMCP具有手术时间短、术中出血少、创伤小及术后恢复快等诸多优点,是治疗腰椎单节段伴有神经根压迫症状的脊柱转移瘤安全、有效的微创手术。

Comparison of Three Data-Driven Networked Predictive Control Methods for a Class of Nonlinear Systems

Dear Editor,In this letter,in order to deal with random network delays and packet losses in a class of networked nonlinear systems,three data-driven networked predictive control methods are designed.Their closed-loop systems and control increments are derived,respectively.

Heat-related illness in Jinshan District of Shanghai:A retrospective analysis of 70 patients

BACKGROUND: This study aimed to investigate the epidemiological and clinical characteristics of patients with heat-related illness, and guide the prevention, diagnosis and treatment of heat-related illness.METHODS: From June 2013 to August 2013, seventy patients with heat-related illness were treated at Jinshan Hospital of Fudan University, and their epidemiological characteristics, laboratory results, treatment and prognosis were retrospectively analyzed.RESULTS: In the 70 patients, 18 patients suffered from heat stroke and 52 patients from nonheat stroke. When the environmnent temperature was above 35 °C, the body temperature of the patients began to increase markedly. The patients with heat stroke were significantly older than those with non-heat stroke(P<0.05). The body temperature, heart rate, blood glucose, blood lactate dehydrogenase and blood creatine kinase in the patients with heat stroke were higher than those in the patients with non-heat stroke(P<0.05). Blood lactate dehydrogenase and blood creatine kinase were positively correlated with body temperature(r=0.801).CONCLUSION: When the environmental temperature goes above 35 °C, heat-related illness should be prevented, especially in the elderly. The body temperature, heart rate, blood glucose, blood lactate dehydrogenase and blood creatine kinase in patients with heat stroke are higher than those in patients with non-heat stroke. Blood lactate dehydrogenase and blood creatine kinase are positively correlated with body temperature, but their relationship with heat-related illness awaits further study.

Efficacy of Shugan Hewei Therapy for Chronic Atrophic Gastritis:A Systematic Review and Meta-Analysis

Objective:Shugan Hewei therapy(SHT)acts to soothe the liver and harmonize the stomach.It is a classical traditional Chinese medicine method widely used in China to treat chronic atrophic gastritis(CAG)due to liver qi invading the stomach.However,the clinical effects of SHT remain unclear.We aimed to evaluate the overall clinical effective rate and safety of SHT in treating CAG.Methods:We used the Jadad scale and Cochrane Collaboration risk of bias tool to evaluate the methodological quality of studies investigating SHT.Eight medical databases were searched to identify relevant studies.After data extraction and quality evaluation,27 randomized controlled trials,including 2,441 patients,were considered eligible for analysis.No serious heterogeneity or publication bias was observed across the included studies.We used Revman 5.3 statistical software to evaluate the general clinical effective rate and safety of SHT.Results:The results showed that SHT was more effective(RR=1.25;95%CI[1.20,1.29];P<0.01)and safer(MD=0.24,95%CI[0.08,0.75];P<0.01)than control interventions comprising western medicine,Chinese patent medicine,and/or western medicine+Chinese patent medicine.Compared with the control interventions,SHT resulted in greater improvements in the symptom scores for stomach distension and stomachache,serum gastrin level,histopathologic changes,Helicobacter pylori(HP)inhibition rate,and gastric mucosal inflammation.Conclusion:SHT was more effective and safer than control interventions for CAG.

Diagnosis and management of arterioportal fistula occurring after percutaneous transhepatic portal vein cannula-assisted TIPS

To the Editor:Transjugularintrahepaticportosystemicshunt(TIPS)isusuallyconsideredthechoiceformanagingcomplicationsofportal hypertensionsuchasrefractoryascites,esophagogastricvariceal bleedingandrecurrentbleedinguncontrolledwithfirstline treatment.Inrecentyears,TIPShasbeensuccessfullyusedto treat Budd-Chiari syndrome, hepatic hydrothorax, and portal vein thrombosis.One of the key steps during TIPS is the portal vein puncture.

Exploring the characteristics of inquiry and the correlation with TCM syndromes about the patients with cardiovascular disease

Objective:Inquiry occupies an important position in the Traditional Chinese Medicine(TCM)diagnostic methods.Observing the characteristics of inquiry symptoms and the correlation with TCM syndromes can determine the important guiding significance to build recognition model and diagnostic criteria of syndrome.Methods:In this study,we collected 3707 valid cases,analyzed the inquiry symptoms of patients with cardiovascular disease,then to explore the distribution of inquiry information and the correlation with TCM syndromes based on the methods,such as frequency analysis,expert score,and correlation analysis.Results:We found the symptoms of frequency analysis and expert symptom score all in the top 50,add up to 41.According to the results by correlation analysis,the correlation coefficient between each symptom and each syndrome are sorted from high to low,the same with the experts score to each inquiry symptom basing on its importance of in diagnosing each syndrome.Conclusion:Inquiry occupies an important effect in differentiation syndrome.This research could provide certain objective basis for establishment of TCM syndromes diagnostic criteria of cardiovascular disease,thus provide some ideas and methods for the research of establishing TCM syndrome identification model,then to provide a reference for the syndrome standardization and objectification.

Propanetricarboxylic acid ornamented multi-Ce^(Ⅲ) encapsulated phospho(Ⅲ) tungstate and its electrochemical sensing properties

A propanetricarboxylic acid ornamented multi-CeⅢencapsulated phospho(Ⅲ)tungstate[H_(2)N(CH_(3))_(2)]_(4)Na_(4)H_(2)[Ce_(4)(HP)W_(4)(H_(2)0)_(14)(H_(2)PTCA)_(2)O_(18)][(HPⅢ)_(2)W_(22)O_(76)]·16H_(2)O(1,H_(3)PTCA=1,2,3-propanetricarboxylic acid)was obtained by a facile one-step reaction of Na_(2)WO_(4)·2H_(2)O,H_(3)PO_(3),Ce(NO_(3))·6H_(2)O,itaconic acid(H2ICA)and dimethylamine hydrochloride.Notably,the polyanion of 1 possesses a neotype[(HP^(Ⅲ))_(2)W_(22)O_(76)]12-fragment and an unusual[HP^(Ⅲ)W_(4)O_(18)]^(8-)unit bridge d by fourCe^(3+)centers in the assistance of two H2PTCA-ligands.It is worth emphasizing that two H2PTCA-ligands simultaneously chelate with WⅥand CeⅢcenters.Furthermore,the composite of 1 and carboxyl-functionalized multi-walled carbon nanotube(CMCN)is utilized to modify glassy carbon electrode(GCE)to develop the 1@CMCN/GCE electrochemical sensor.The 1@CMCN/GCE electrochemical sensor displays potential sensing property toward detection of noradrenaline(NDL)with low limit of 2.10μmo1·L^(-1).This research will powerfully facilitate continuous investigations on rational design and in-depth development of structure-oriented rare-earth inserted phospho(Ⅲ)tungstates and tremendously promote their application developments in drug testing,clinical diagnosis,and food detection.