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Control Strategies for Digital Twin Systems

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IEEE/CAA Journal of Automatica Sinica 2024年第1期11卷 170-180页

作者： Guo-ping liu IEEE the Center for Control Science and Technology Southern University of Science and TechnologyShenzhen 518055China

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 *** 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.

关键词： Digital twin control systems fault tolerant control model tracking performance prediction performance retention

Vitreoretinal surgeons'experience and time interval from pars-plana vitrectomy to cataract extraction

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International Journal of Ophthalmology(English edition) 2021年第1期14卷 120-126页

作者： Yan-Xin Xu liang-ping liu Jian-Bing Li Huan-Huan Cheng Min Hou Lin Lu Ming-Xing Wu State Key Laboratory of Ophthalmology Zhongshan Ophthalmic CenterSun Yat-sen UniversityGuangzhou 510060Guangdong ProvinceChina

AIM:To identify the association of the vitreoretinal surgeons'experience with the time interval between parsplana vitrectomy(PPV)and cataract extraction(CE).METHODS:Eyes with prior PPV and following CE were included in this retrospective cohort *** years of practice and the annual case volume were used to describe the surgeons'*** linear regression analysis was used to investigate the relationship between surgeons'experience and the time interval adjusted for the patients age,gender,intraocular tamponade,and case ***:Of 132430 eyes,1445 eyes were included in this *** multivariable linear regression analysis,cases performed by surgeons with>20 practice years had longer time intervals compared with surgeons with<10 practice years after adjusted for other variables(β=0.329,95%CI:0.113 to 0.549,P=0.003).No difference in time interval was detected for comparing the lowest with the highest volume groups(β=0.089,95%CI:-0.164 to 0.343,P=0.343).The surgeons'practice years were not directly with the *** complicated surgery,the higherpractice-year surgeons had longer time interval than lowerpractice-year ***:The time intervals from PPV to CE is longer in higher-practice-year *** surgeons'practice years may have a greater effect on the time interval than annual case volume in high-complexity *** the complexity of vitreoretinal diseases with the surgeons'practice year should be considered.

关键词： pars-plana vitrectomy cataract time interval experience annual case volume

Comparison of early changes in ocular surface markers and tear inflammatory mediators after femtosecond lenticule extraction and FS-LASIK

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International Journal of Ophthalmology(English edition) 2021年第2期14卷 283-291页

作者： Chi Zhang Hui Ding Hong He He Jin liang-ping liu Xiao-Wei Yang Jun Yang Xing-Wu Zhong Huaxia Eye Hospital of Foshan Huaxia Eye Hospital GroupFoshan 528000Guangdong ProvinceChina Zhongshan Ophthalmic Center and State Key Laboratory of Ophthalmology Sun Yat-sen UniversityGuangzhou 510000Guangdong ProvinceChina Hainan Eye Hospital and Key Laboratory of Ophthalmology Zhongshan Ophthalmic CenterSun Yat-sen UniversityHaikou 570311Hainan ProvinceChina

AIM:To compare the short-term impacts of femtosecond lenticule extraction(FLEx)and femtosecond laser-assisted laser in situ keratomileusis(FS-LASIK)on ocular surface measures and tear inflammatory ***:This prospective comparative nonrandomized clinical study comprised 75 eyes(75 patients).Totally 20 male and 15 female patients(age 21.62±3.25 y)with 35 eyes underwent FLEx,and 26 male and 14 female patients(age 20.18±3.59 y)with 40 eyes underwent *** corneal sensitivity,noninvasive tear breakup time,corneal fluorescein staining,Schirmer I test,tear meniscus height,and ocular surface disease index were evaluated in all *** concentrations of nerve growth factor(NGF),interleukin-1α(IL-1α),transforming growth factor-β1(TGF-β1),tumor necrosis factor-α(TNF-α),interferon-γ(IFN-γ),and matrix metalloproteinase-9(MMP-9)were assessed by multiplex antibody *** measurements were performed preoperatively,and 1 d,1 wk,and 1 mo ***:Patients who underwent FLEx exhibited a more moderate reduction in central corneal sensation and less corneal fluorescein staining than those in the FS-LASIK group 1 wk after the procedure(P<0.01).NGF was significantly higher 1 d and 1 wk after surgery in the FS-LASIK group than in the FLEx group(P<0.01).By contrast,compared to those in the FLEx group,higher postoperative values and slower recovery of tear TGF-β1,IL-1α,and TNF-αconcentrations were observed in the FS-LASIK group(P<0.01).Tear concentrations of NGF,TGF-β1,TNF-α,and IL-1αwere correlated with ocular surface changes after FLEx or FS-LASIK ***:There is less early ocular surface disruption and a reduced inflammatory response after FLEx than after ***,TGF-β1,TNF-α,and IL-1αmay contribute to the process of ocular surface recovery.

关键词： femtosecond lenticule extraction femtosecond laser-assisted laser in situ keratomileusis tear inflammatory mediators ocular surface

Stories of Today's Bai Nationality Women

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Women of China 1996年第8期 15-17页

作者： liang ping liu QIAN

The Bai nationality has a population of over one and a half million. Most of them live in the Dali Bai Nationality Autonomous Prefecture in Yunnan Province. The Bai nationality people have ived with the Han natignality for a long time, and in the Bai language there are a number of Han words. The Bai nationality is ancient. Their ancestors first settled in the Erhai area in the first century A.D. In the second century,

关键词： In Stories of Today’s Bai Nationality Women

Super-high bed sintering for iron ores: inhomogeneous phenomena and its mechanism during mineralizing

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Journal of Iron and Steel Research International 2024年第8期31卷 1850-1860页

作者： Hui-bo liu liang-ping Xu Xi-duan Yang Zhong-lin Dong Qiang Zhong Guang-hui Li School of Minerals Processing and Bioengineering Central South UniversityChangsha 410083HunanChina

The inhomogeneous sinter properties in super-high bed sintering have been reported in our previous *** inves-tigate the reasons for the inhomogeneous phenomena,detailed sampling and analysis of mixed material bed and sintered bed in super-high bed sintering plant were *** results indicated that the higher porosity and thinner dendrite of silico-ferrite of calcium and aluminum in the upper layer as well as dense structure and higher secondary hematite content in the lower layer led to the heterogeneities of mechanical strength and reduction properties exceeding 20%and 10%,*** the bed top downward,the basicity of mixed material decreased from 2.13 to 1.68 because the average particle size increased from 2.65 to 4.56 *** and fuels gathered in finer particles(-3 mm)of mixed material,and the-3 mm particles of mixed material generated more liquid phase than+3 mm *** heat input of super-high sintering bed was inhomogeneous due to the heat accumulation effect and unreasonable fuel *** inhomo-geneous sintering heat condition in sintering bed resulted in the different quantities and properties of liquid *** inhomogeneous quantities and properties of liquid phase that were influenced by inhomogeneous distribution of chemical composition,particle size,and heat input led to inhomogeneous mineralizing *** mineralizing condition is the key for homogeneous super-high bed sintering.

关键词： Iron ore Super-high bed sintering Mineralization Material segregation Heat accumulation

Super-high bed sintering for iron ores:behaviors,causes and solutions of horizontal segregation on strand

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Journal of Iron and Steel Research International 2024年第7期31卷 1590-1596页

作者： liang-ping Xu Hui-bo liu Zhong-lin Dong Qiang Zhong Yu-chao Zhao Guang-hui Li School of Minerals Processing and Bioengineering Central South UniversityChangsha 410083HunanChina

Horizontal segregation has been a constraint to the development and application of super-high bed *** eliminate the horizontal segregation of super-high bed sintering,several typical sintering machines were sampled and analyzed,and theoretical calculation was made to compare the bed depth and their differences in different areas within the mixture ***,solutions were proposed and applied to a 265 m^(2) sintering *** results showed that the horizontal seg-regation of the 265 m^(2) sintering machine was dominated by particles larger than 8 mm with horizontal segregation degree of 0.48,while 360 and 550 m^(2) sintering machines were affected by 5-8 mm and 1-3 mm particles with horizontal segregation degree of 0.27 and 0.31,*** analysis indicated the different segregation distribution results from the matching of the bed depth of each area within the mixture ***,the horizontal segregation degree not larger than 0.06 was achieved by optimizing the time parameters and the division of three zones on the 265 m^(2) sintering machine.

关键词： Super-high bed sintering Horizontal segregation Feeder Particle distribution Agglomeration

Perinatal prevalence of birth defects in the Mainland of China,2000–2021:a systematic review and meta-analysis

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World Journal of Pediatrics 2024年第7期20卷 669-681页

作者： liang-Yu Kang Zi-Rui Guo Wei-Jing Shang Gui-Ying Cao Yi-ping Zhang Qiao-Mei Wang Hai-ping Shen Wan-Nian liang Min liu Department of Epidemiology and Biostatistics School of Public HealthPeking UniversityNo.38Xueyuan RoadHaidian DistrictBeijing100191China Vanke School of Public Health Tsinghua UniversityNo.1Tsinghua GardenHaidian DistrictBeijing100084China Department of Maternal and Child Health National Health Commission of the People’s Republic of ChinaNo.1Xizhimenwai South RoadXicheng DistrictBeijingChina Institute of Healthy China Tsinghua UniversityNo.1Tsinghua GardenHaidian DistrictBeijing100084China Key Laboratory of Epidemiology of Major Diseases(Peking University) Ministry of Education BeijingNo.38Xueyuan RoadHaidian DistrictBeijing100191China

Background Although birth defects are of great concern globally,the latest national prevalence has not yet been quantified in *** conducted a systematic review and meta-analysis to estimate the perinatal prevalence of birth defects in the Mainland of China between 2000 and *** We performed a systematic literature search of six databases for relevant articles published between January 1,2000,and March 1,*** included published studies that reported data on the perinatal prevalence of birth defects in the Mainland of *** DerSimonian and Laird random-effects models were used to estimate the pooled prevalence and its 95%confidence interval(CI).We also conducted subgroup analyses and univariable meta-regressions to explore differences in prevalence by time period,geographic region,and other *** We included 254 studies reporting the perinatal prevalence of birth defects and 86 studies reporting only the prevalence of specific types of birth *** on 254 studies covering 74,307,037 perinatal births and 985,115 cases with birth defects,the pooled perinatal prevalence of birth defects was 122.54(95%CI 116.20–128.89)per 10,000 perinatal births in the Mainland of China during 2000–***,the perinatal prevalence of birth defects increased from 95.60(86.51–104.69)per 10,000 in 2000–2004 to 208.94(175.67–242.22)per 10,000 in 2020–*** were also significant disparities among different geographical *** heart defects(33.35 per 10,000),clefts of the lip and/or palate(13.52 per 10,000),polydactyly(12.82 per 10,000),neural tube defects(12.82 per 10,000),and inborn errors of metabolism(11.41 per 10,000)were the five most common types of birth *** perinatal prevalence among males was significantly higher than that among females(β=2.44×10^(−3),P=0.003);a higher perinatal prevalence of birth defects was observed among perinatal births whose mothers were≥35 years(β=4.34×10^(−3),P<0.001).Conclusion Compreh

关键词： Birth defects China Perinatal Prevalence

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

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IEEE/CAA Journal of Automatica Sinica 2024年第5期11卷 1250-1261页

作者： Wei Chen Guo-ping liu The authors are with the Center for Control Science and Technology Southern University of Science and TechnologyShenzhen 518055China

This paper studies the privacy-preserving distributed economic dispatch(DED)problem of smart *** 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 *** 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 *** 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 *** 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 *** particular,the proposed autonomous algorithm can achieve a smooth transition between the islanded mode and the grid-connected ***,rigorous analysis is given to show privacy-preserving performance against internal and external ***,case studies illustrate the feasibility and validity of the developed algorithm.

关键词： preserving autonomous mode

Mechanical characteristics and reservoir stimulation mechanisms of the Gulong shale oil reservoirs, the northern Songliao Basin

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Petroleum Science 2024年第3期21卷 2023-2036页

作者： Si-Wei Meng Jia-ping Tao Tian-Jiao Li Dong-Xu Li Su-Ling Wang liu Yang Xin liu Li-Hao liang He liu PetroChina Research Institute of Petroleum Exploration Development Beijing100083China National Key Laboratory of Continental Shale Oil Daqing 163002HeilongjiangChina Dalian University of Technology Dalian116024LiaoningChina PetroChina Daqing Oilfield Co.Ltd. Daqing163002HeilongjiangChina Northeast Petroleum University Daqing163002HeilongjiangChina China University of Mining and Technology(Beijing) Beijing100083China

Shale oil of the Qingshankou Formation of the Gulong Sag,the northern Songliao Basin,represents the first attempt at large-scale development of pure-shale-type shale oil in *** integrating the multiscale refined reservoir characterization with macro-micro-scale mechanical testing,it is clarified that the Gulong shale is characterized by high clay mineral content,high rock plasticity,highly-developed bedding,and prominent mechanical anisotropy.A three-dimensional(3D)fracture propagation model of hydraulic fracturing was built for the Gulong shale,which fully captures the hydraulic fracture distribution pattern affected by the high bedding density,in-situ stress,and fracturing treatment *** research showed that due to influences of bedding,hydraulic fracturing in the Gulong shale forms a complex fracture morphology featuring the main fracture with multiple perpendicular branches that have different lengths(like the outdoor directional TV antenna);however,the vertical propagation of fractures is inhibited,and the fracture height is commonly less than 10 *** limited stimulated reservoir volume(SRV)is the main problem facing the fracturing stimulation of the Gulong shale *** density has vital effects on fracture morphology,so case-specific fracturing designs shall be developed for shale intervals with different bedding development *** reservoirs with welldeveloped bedding,it is suggested to properly increase the perforation cluster spacing and raise the volume and proportions of viscous fluids of the pad,so as to effectively promote vertical fracture propagation and improve reservoir stimulation *** study integrates multi-scale fine reservoir characterization and macro-micro-scale mechanical testing,as well as the construction and numerical simulation of hydraulic fracturing models for high-density layered shale reservoirs,providing a new approach and methodological framework for the fracturing research of high-density layer

关键词： Shale oil Hydraulic fracturing High bedding density Fracture propagation model