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Wind Power Generation Variations and Aggregations

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CSEE Journal of Power and Energy Systems 2022年第1期8卷 17-38页

作者： Cong Wu Xiao-Ping Zhang Michael Sterling Department of Energy Strategy and Planning State Grid Energy Research InstituteBeijingChina Systems Engineering School of EngineeringUniversity of BirminghamBirmingham B152TTU.K Department of Electronic Electrical and Systems EngineeringSchool of EngineeringUniversity of BirminghamBirmingham B152TTU.K

Climate and weather-propelled wind power is characterized by significant spatial and temporal variability.It has been substantiated that the variability of wind power,in addition to contributing hugely to the instability of power grids,can also send the balancing costs of electricity markets soaring.Existing studies on the same establish that curtailment of such variability can be achieved through the geographic aggregation of various widespread production sites;however,there exists a dearth of comprehensive evaluation concerning different levels/scales of such aggregation,especially from a global perspective.This paper primarily offers a fundamental understanding of the relationship between the wind power variations and aggregations from a systematic viewpoint based on extensive wind power data,thereby enabling the benefits of these aggregations to be quantified from a state scale ranging up to a global scale.Firstly,a meticulous analysis of the wind power variations is undertaken at 6 different levels by converting the 7-year hourly meteorological re-analysis data with a high spatial resolution of 0.25◦×0.25◦(approximate 28 km×28 km)into a wind power series globally.Subsequently,the proposed assessment framework employs a coefficient of variation of wind power as well as a standard deviation of wind power ramping rate to quantify the variations of wind power and wind power ramping rate to exhibit the characteristics and benefits yielded by the wind power aggregation at 6 different levels.A system planning example is adopted to illustrate the correlation between the coefficient of variation reduction of wind power and investment reduction,thereby emphasizing the benefits pertaining to significant investment reduction via aggregation.Furthermore,a wind power duration curve is used to exemplify the availability of wind power aggregated at different levels.Finally,the results provide insights into devising a universal approach towards the deployment of wind power,principally along the lines of Net-Zero.

关键词： Energy quality meteorological re-analysis data wind power aggregation wind power ramping rate wind power variation wind power variability

DELAY-DEPENDENT STABILITY OF LINEAR MULTISTEP METHODS FOR NEUTRAL SYSTEMS WITH DISTRIBUTED DELAYS

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Journal of Computational Mathematics 2022年第3期40卷 484-498页

作者： Yuhao cong Shouyan wu Shanghai Customs College Shanghai 201204China Department of Mathematics Zhejiang International Studies UniversityHangzhou 310023China Department of Mathematics Shanghai Normal UniversityShanghai 200234China

This paper considers the asymptotic stability of linear multistep(LM)methods for neutral systems with distributed delays.In particular,several sufficient conditions for delay-dependent stability of numerical solutions are obtained based on the argument principle.Compound quadrature formulae are used to compute the integrals.An algorithm is proposed to examine the delay-dependent stability of numerical solutions.Several numerical examples are performed to verify the theoretical results.

关键词： Neutral systems with distributed delays Linear multistep methods Delaydependent stability Argument principle

Pattern-based learning and control of nonlinear pure-feedback systems with prescribed performance

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Science China(Information Sciences) 2023年第1期66卷 188-209页

作者： Fukai ZHANG Weiming wu cong WANG Center for Intelligent Medical Engineering School of Control Science and EngineeringShandong University

This article presents a novel pattern-based intelligent control scheme with prescribed performance(PP) for uncertain pure-feedback systems operating in multiple control situations(patterns). Based on PP,an observer-based adaptive neural network(NN) control approach, which not only achieves system stability and prescribed tracking control performance but also realizes accurate identification/learning of the unknown closed-loop dynamics via deterministic learning and uses only one NN unit, is proposed. Subsequently, the knowledge learned is utilized to construct high-performance candidate controllers for each control situation.Based on the transformed system and observer technique, accurate classification of the nth order systems under different control situations is achieved by requiring only one set of dynamic estimators, thereby significantly reducing the complexity of pattern recognition. Thus, sudden changes in the control situation can be rapidly recognized based on the minimum residual principle, with which the correct candidate controller is selected to achieve superior control performance. The simulation results verify the efficacy of the proposed scheme.

关键词： adaptive neural control (ANC) deterministic learning neural networks (NNs) pattern-based control high gain observer pure-feedback systems

Iron-Catalyzed Reductive C(aryl)—Si Cross-Coupling of Diaryl Ethers with Chlorosilanes

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Chinese Journal of Chemistry 2024年第6期42卷 578-584页

作者： Pei Liu Baowei wu Xuefeng cong Jie Kong School of Chemistry and Chemical Engineering Northwestern Polytechnical UniversityXi'anShaanxi710072 China Institute of Molecular Plus Department of Chemistry and Haihe Laboratory of Sustainable Chemical TransformationsTianjin University92 Weijin RoadTianjin300072 China

The reductive cross-coupling between C(aryl)—O and Si—Cl bonds is of much importance as a valuable strategy for the construction of C(aryl)—Si bonds but has remained a great challenge.Herein,we report a reductive cross-coupling of diaryl ethers and chlorosilanes via strong electrophilic C(aryl)—O and Si—Cl bonds cleavage by iron catalysis,which constitutes an efficient protocol for the synthesis of a range of functionalized arylsilanes.The combination of low cost FeCl2 as the precatalyst and iPrMgCl as the reductant shows high activity in the successive cleavage of unactivated C(aryl)—O bonds of diaryl ethers and strong electrophilic Si—Cl bonds of chlorosilanes,allowing their cross-coupling in a reductive fashion.The low-valent iron species generated in situ by reduction of FeCl2 with iPrMgCl was proposed,which prefers to initially cleavage the C(aryl)—O bond of diaryl ethers with the chelation help of an o-amide auxiliary.

关键词： Cross-coupling Diaryl ethers Chlorosilanes C—O bond cleavage Iron catalyst 3d transition metals Selectivity Regioselectivity

Dynamical pattern recognition for univariate time series and its application to an axial compressor

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Control Theory and Technology 2024年第1期22卷 39-55页

作者： Jingtao Hu Weiming wu Zejian Zhu cong Wang Center for Intelligent Medical Engineering School of Control Science and TechnologyShandong UniversityJinan250061ShandongChina School of Automation Science and Engineering South China University of TechnologyGuangzhou510641GuangdongChina

In this paper, a learning and recognition approach is proposed for univariate time series composed of output measurements of general nonlinear dynamical systems. Firstly, a class of dynamical systems in the canonical form is derived to describe the univariate time series by introducing coordinate transformation. An observer-based deterministic learning technique is then adopted to achieve dynamical modeling of the associated transformed systems of the training univariate time series, and the modeling results in the form of radial basis function network (RBFN) models are stored in a pattern library. Subsequently, multiple observer-based dynamical estimators containing the RBFN models in the pattern library are constructed for a test univariate time series, and a recognition decision scheme is proposed by the derived recognition indicator. On this basis, more concise recognition conditions are provided, which is beneficial for verifying the recognition results. Finally, simulation studies on the Rossler system and aero-engine stall warning verify the effectiveness of the proposed approach.

关键词： Dynamical pattern recognition Deterministic learning Stall warning Radial basis function network Sampled-data observer

Brain Cognition Mechanism-Inspired Hierarchical Navigation Method for Mobile Robots

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Journal of Bionic Engineering 2024年第2期21卷 852-865页

作者： Qiang Zou Chengdong wu Ming cong Dong Liu Faculty of Robot Science and Engineering Northeastern UniversityShenyang110819China School of Mechanical Engineering Dalian University of TechnologyDalian116024China

Autonomous navigation is a fundamental problem in robotics.Traditional methods generally build point cloud map or dense feature map in perceptual space;due to lack of cognition and memory formation mechanism,traditional methods exist poor robustness and low cognitive ability.As a new navigation technology that draws inspiration from mammal’s navigation,bionic navigation method can map perceptual information into cognitive space,and have strong autonomy and environment adaptability.To improve the robot’s autonomous navigation ability,this paper proposes a cognitive map-based hierarchical navigation method.First,the mammals’navigation-related grid cells and head direction cells are modeled to provide the robots with location cognition.And then a global path planning strategy based on cognitive map is proposed,which can anticipate one preferred global path to the target with high efficiency and short distance.Moreover,a hierarchical motion controlling method is proposed,with which the target navigation can be divided into several sub-target navigation,and the mobile robot can reach to these sub-targets with high confidence level.Finally,some experiments are implemented,the results show that the proposed path planning method can avoid passing through obstacles and obtain one preferred global path to the target with high efficiency,and the time cost does not increase extremely with the increase of experience nodes number.The motion controlling results show that the mobile robot can arrive at the target successfully only depending on its self-motion information,which is an effective attempt and reflects strong bionic properties.

关键词： Bionic navigation Spatial localization cells Global path planning Hierarchical motion controlling

A new continuum model with driver's continuous sensory memory and preceding vehicle's taillight

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Communications in Theoretical Physics 2020年第10期72卷 29-41页

作者： cong Zhai Weitiao wu School of Transportation and Civil Engineering and Architecture Foshan UniversityFoshan 528000 GuangdongChina School of Civil Engineering and Transportation South China University of TechnologyGuangzhou 510641 GuangdongChina

Car taillights are ubiquitous during the deceleration process in real traffic,while drivers have a memory for historical information.The collective effect may greatly affect driving behavior and traffic flow performance.In this paper,we propose a continuum model with the driver's memory time and the preceding vehicle's taillight.To better reflect reality,the continuous driving process is also considered.To this end,we first develop a unique version of a car-following model.By converting micro variables into macro variables with a macro conversion method,the micro carfollowing model is transformed into a new continuum model.Based on a linear stability analysis,the stability conditions of the new continuum model are obtained.We proceed to deduce the modified KdV-Burgers equation of the model in a nonlinear stability analysis,where the solution can be used to describe the propagation and evolution characteristics of the density wave near the neutral stability curve.The results show that memory time has a negative impact on the stability of traffic flow,whereas the provision of the preceding vehicle's taillight contributes to mitigating traffic congestion and reducing energy consumption.

关键词： memory time preceding vehicle's taillight continuum model stability modified KdV-Burgers equation

Effect of warpage on the electronic structure and optical properties of bilayer germanene

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Journal of Semiconductors 2022年第12期43卷 39-45页

作者： Qihang Xiong Weifu Cen Xingtong wu cong Chen College of Chemical Engineering Guizhou Minzu UniversityGuiyang 550025China College of Materials Science and Engineering Guizhou Minzu UniversityGuiyang 550025China College of Mechanical and Electrical Engineering Guizhou Minzu UniversityGuiyang 550025China

The electronic structure and optical properties of bilayer germanene under different warpages are studied by the first-principles method of density functional theory.The effects of warpages on the electronic structure and optical properties of bilayer germanene are analyzed.The results of the electronic structure study show that the bottom of the conduction band of bilayer germanene moves to the lower energy direction with the increase of warpages at the K point,and the top of the valence band stays constant at the K point,and so the band gap decreases with the increase of warpage.When the warpage is 0.075 nm,the top of the valence band of bilayer germanene changes from K point to G point,and the bilayer germanene be-comes an indirect band gap semiconductor.This is an effective means to modulate the conversion of bilayer germanene between direct band gap semiconductor and indirect band gap semiconductor by adjusting the band structure of bilayer ger-manene effectively.The study of optical properties shows that the effect of warpage on the optical properties of bilayer ger-manene is mainly distributed in the ultraviolet and visible regions,and the warpage can effectively regulate the electronic struc-ture and optical properties of bilayer germanene.When the warpage is 0.069 nm,the first peak of dielectric function and extinc-tion coefficient is the largest,and the energy corresponding to the absorption band edge is the smallest.Therefore,the elec-tron utilization rate is the best when the warpage is 0.069 nm.

关键词： bilayer germanene warpages electronic structure optical properties first-principles

Chinese American Caregivers’Attitudes Toward Tube Feeding for Persons with Dementia-USA,2021–2022

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China CDC weekly 2022年第47期4卷 1051-1054,I0001-I0002页

作者： Yaolin Pei Xiang Qi Zhen cong Bei wu Rory Meyers College of Nursing New York UniversityNew YorkUSA School of Social Work University of Texas at ArlingtonArlingtonUSA.

Summary What is already known about this topic?Little is known about Chinese American dementia caregivers’attitudes toward tube feeding.What is added by this report?To address this knowledge gap,the paper seeks to characterize participants’attitudes toward tube feeding based on a survey conducted among Chinese American dementia caregivers.What are the implications for public health practice?It is crucial to develop culturally tailored interventions to promote knowledge on tube feeding and advance care planning engagement in Chinese American communities.

关键词： Care knowledge feeding