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A survey on book-embedding of planar graphs

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Frontiers of Mathematics in China 2022年第2期17卷 255-273页

作者： Xiaxia GUAN Chuxiong WU Weihua Yang Jixiang MENG College of Mathematics Taiyuan University of TechnologyTaiyuan 030024China College of Mathematics and System Science Xinjiang UniversityUrumqi 830046China

The book-embedding problem arises in several area,such as very large scale integration(VLSI)design and routing multilayer printed circuit boards(PCBs).It can be used into various practical application fields.A book embedding of a graph G is an embedding of its vertices along the spine of a book,and an embedding of its edges to the pages such that edges embedded on the same page do not intersect.The minimum number of pages in which a graph G can be embedded is called the pagenumber or book-thickness of the graph G.It is an important measure of the quality for book-embedding.It is NP-hard to research the pagenumber of book-embedding for a graph G.This paper summarizes the studies on the book-embedding of planar graphs in recent years.

关键词： Book embedding planar graphs pagenumber

HCSP-Net:A Novel Model of Age-RelatedMacular Degeneration Classification Based on Color Fundus Photography

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Computers, Materials & Continua 2024年第4期79卷 391-407页

作者： Cheng Wan Jiani Zhao Xiangqian Hong Weihua Yang Shaochong Zhang College of Electronic and Information Engineering/College of Integrated Circuits Nanjing University of Aeronautics and AstronauticsNanjing211106China Shenzhen Eye Institute Shenzhen Eye HospitalJinan UniversityShenzhen518040China

Age-related macular degeneration(AMD)ranks third among the most common causes of blindness.As the most conventional and direct method for identifying AMD,color fundus photography has become prominent owing to its consistency,ease of use,and good quality in extensive clinical practice.In this study,a convolutional neural network(CSPDarknet53)was combined with a transformer to construct a new hybrid model,HCSP-Net.This hybrid model was employed to tri-classify color fundus photography into the normal macula(NM),dry macular degeneration(DMD),and wet macular degeneration(WMD)based on clinical classification manifestations,thus identifying and resolving AMD as early as possible with color fundus photography.To further enhance the performance of this model,grouped convolution was introduced in this study without significantly increasing the number of parameters.HCSP-Net was validated using an independent test set.The average precision of HCSPNet in the diagnosis of AMD was 99.2%,the recall rate was 98.2%,the F1-Score was 98.7%,the PPV(positive predictive value)was 99.2%,and the NPV(negative predictive value)was 99.6%.Moreover,a knowledge distillation approach was also adopted to develop a lightweight student network(SCSP-Net).The experimental results revealed a noteworthy enhancement in the accuracy of SCSP-Net,rising from 94%to 97%,while remarkably reducing the parameter count to a quarter of HCSP-Net.This attribute positions SCSP-Net as a highly suitable candidate for the deployment of resource-constrained devices,which may provide ophthalmologists with an efficient tool for diagnosing AMD.

关键词： Computer-aided diagnosis deep learning age-related macular degeneration transformer

Conservation and Utilization of Genetic Resources of Wild Rice in China

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Rice science 2022年第3期29卷 216-224页

作者： yang Ziyi XU Zhijian yang Qingwen QIAO weihua Institute of Crop Sciences Chinese Academy of Agricultural SciencesBeijing 100081China Rice Research Institute Guangxi Academy of Agricultural SciencesNanning 530007China

The abundant genetic resources of wild rice in China represent a key gene pool for modern rice breeding,contributing to food production and agricultural development in China and worldwide.Between the 1970s and the 2010s,two national wild rice surveys were carried out in China.More than 20000accessions of three species Oryza rufipogon,O.officinalis and O.meyeriana have been conserved ex situ.An in situ conservation system has also been set up to protect notable and endangered populations.This review summarized the geographical distribution of wild rice in China,the current status of conservation,the discovery of elite genes,and the application of research into the origin and domestication of rice.

关键词： wild rice conservation valuable gene origin and domestication

Integral Event-Triggered Attack-Resilient Control of Aircraft-on-Ground Synergistic Turning System With Uncertain Tire Cornering Stiffness

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IEEE/CAA Journal of Automatica Sinica 2023年第5期10卷 1276-1287页

作者： Chenglong Du Fanbiao Li yang Shi Chunhua yang weihua Gui the School of Automation Central South UniversityChangsha 410083China the Department of Mechanical Engineering University of VictoriaVictoria BC V8W 3P6Canada

This article proposes an integral-based event-triggered attack-resilient control method for the aircraft-on-ground(AoG) synergistic turning system with uncertain tire cornering stiffness under stochastic deception attacks. First, a novel AoG synergistic turning model is established with synergistic reverse steering of the front and main wheels to decrease the steering angle of the AoG fuselage, thus reducing the steady-state error when it follows a path with some large curvature. Considering that the tire cornering stiffness of the front and main wheels vary during steering, a dynamical observer is designed to adaptively identify them and estimate the system state at the same time.Then, an integral-based event-triggered mechanism(I-ETM) is synthesized to reduce the transmission frequency at the observerto-controller end, where stochastic deception attacks may occur at any time with a stochastic probability. Moreover, an attackresilient controller is designed to guarantee that the closed-loop system is robust L2-stable under stochastic attacks and external disturbances. A co-design method is provided to get feasible solutions for the observer, controller, and I-ETM simultaneously. An optimization program is further presented to make a tradeoff between the robustness of the control scheme and the saving of communication resources. Finally, the low-and high-probability stochastic deception attacks are considered in the simulations. The results have illustrated that the AoG synergistic turning system with the proposed control method follows a path with some large curvature well under stochastic deception attacks. Furthermore,compared with the static event-triggered mechanisms, the proposed I-ETM has demonstrated its superiority in saving communication resources.

关键词： Adaptive observer aircraft-on-ground(AoG)synergistic turning attack-resilient controller integral-based event-triggered mechanism L_2-stability

Multi-Objective Adaptive Optimization Model Predictive Control:Decreasing Carbon Emissions from a Zinc Oxide Rotary Kiln

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Engineering 2023年第8期27卷 96-105页

作者： Ke Wei Keke Huang Chunhua yang weihua Gui School of Automation Central South UniversityChangsha 410083China

The zinc oxide rotary kiln,as an essential piece of equipment in the zinc smelting industrial process,is presenting new challenges in process control.China’s strategy of achieving a carbon peak and carbon neutrality is putting new demands on the industry,including green production and the use of fewer resources;thus,traditional stability control is no longer suitable for multi-objective control tasks.Although researchers have revealed the principle of the rotary kiln and set up computational fluid dynamics(CFD)simulation models to study its dynamics,these models cannot be directly applied to process control due to their high computational complexity.To address these issues,this paper proposes a multi-objective adaptive optimization model predictive control(MAO-MPC)method based on sparse identification.More specifically,with a large amount of data collected from a CFD model,a sparse regression problem is first formulated and solved to obtain a reduction model.Then,a two-layered control framework including real-time optimization(RTO)and model predictive control(MPC)is designed.In the RTO layer,an optimization problem with the goal of achieving optimal operation performance and the lowest possible resource consumption is set up.By solving the optimization problem in real time,a suitable setting value is sent to the MPC layer to ensure that the zinc oxide rotary kiln always functions in an optimal state.Our experiments show the strength and reliability of the proposed method,which reduces the usage of coal while maintaining high profits.

关键词： Zinc oxide rotary kiln Model reduction Sparse identification Real-time optimization Model predictive control Process control

Modified graph systems for distributed optimization

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Science China(Information Sciences) 2023年第12期66卷 48-63页

作者： Zicong XIA yang LIU Dongyun WANG weihua GUI Key Laboratory of Intelligent Education Technology and Application of Zhejiang Province School of Mathematical Sciences Zhejiang Normal University College of Engineering Zhejiang Normal University School of Information Science and Engineering Central South University

In distributed optimization theory, network topology graphs are important in communications among multiple agents. However, distributed optimization approaches cannot solve optimization problems well if the graphs are infeasible or tampered. To this end, this paper develops two types of modified graph systems for modifying or recovering the communication graphs among agents employed in distributed optimization. Two optimization problems for obtaining feasible graphs are formulated. Based on the two optimization problems, two modified graph systems are derived accordingly and their convergence to the optimal solution is proven. Via a coordination mechanism consisting of a distributed optimization approach and a modified graph system, we can modify an infeasible communication graph into a feasible one or recover a tampered graph, and the distributed optimization approach can resume its solver capability with the modified graphs. Several examples are provided to demonstrate the efficiency of the main results.

关键词： distributed optimization modified graph system neurodynamic optimization communication graph

Matrix-valued distributed stochastic optimization with constraints

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信息与电子工程前沿:英文版 2023年第9期24卷 1239-1252页

作者： Zicong XIA yang LIU Wenlian LU weihua GUI Key Laboratory of Intelligent Education Technology and Application of Zhejiang Province Zhejiang Normal UniversityJinhua 321004China School of Mathematical Sciences Zhejiang Normal UniversityJinhua 321004China School of Mathematical Sciences Fudan UniversityShanghai 200433China School of Automation Central South UniversityChangsha 410083China

In this paper,we address matrix-valued distributed stochastic optimization with inequality and equality constraints,where the objective function is a sum of multiple matrix-valued functions with stochastic variables and the considered problems are solved in a distributed manner.A penalty method is derived to deal with the constraints,and a selection principle is proposed for choosing feasible penalty functions and penalty gains.A distributed optimization algorithm based on the gossip model is developed for solving the stochastic optimization problem,and its convergence to the optimal solution is analyzed rigorously.Two numerical examples are given to demonstrate the viability of the main results.

关键词： Distributed optimization Matrix-valued optimization Stochastic optimization Penalty method Gossip model

Fixed-time distributed robust optimization for economic dispatch with event-triggered intermittent control

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Science China(Technological Sciences) 2023年第5期66卷 1385-1396页

作者： HUANG BangHua LIU yang GLIELMO Luigi GUI weihua Key Laboratory of Intelligent Education Technology and Application of Zhejiang Province Zhejiang Normal UniversityJinhua321004China School of Mathematical Sciences Zhejiang Normal UniversityJinhua321004China Department of Electrical Engineering and Information Technologies University of Naples FedericoⅡNapoli80125Italy School of Automation Central South UniversityChangsha410083China

This paper proposes a fixed-time distributed robust optimization approach for solving economic dispatch problems.Based on an integral sliding mode control scheme,the proposed multi-agent system converges to an optimal solution to an economic dispatch problem before a fixed time.In addition,the proposed multi-agent system can suppress the disturbance in a fixed time.To reduce the cost of sliding mode controls,we propose a distributed event-triggered intermittent control which reduces the sliding mode control time by setting a control triggering rule on the basis of two boundary functions of a Lyapunov function.The simulation results of three power systems illustrate the characteristics and effectiveness of the theoretical results.

关键词： distributed optimization economic dispatch problem fixed-time robust optimization event-triggered intermittent control

Experimental analysis of pore structure and fractal characteristics of soft and hard coals with same coalifcation

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International Journal of Coal Science & Technology 2022年第4期9卷 107-121页

作者： Barkat Ullah Yuanping Cheng Liang Wang Weihua Yang Izhar Mithal Jiskani Biao Hu School of Safety Engineering China University of Mining and TechnologyXuzhouChina School of Resources and Safety Engineering Central South UniversityChangshaChina NUST Balochistan Campus National University of Sciences and TechnologyQuettaPakistan

Accurate and quantitative investigation of the physical structure and fractal geometry of coal has important theoretical and practical signifcance for coal bed methane(CBM)development and the prevention of dynamic disasters such as coal and gas outbursts.This study investigates the pore structure and fractal characteristics of soft and hard coals using nitrogen and carbon dioxide(N_(2)/CO_(2))adsorption.Coal samples from Pingdingshan Mine in Henan province of China were collected and pulverized to the required size(0.20–0.25 mm).N_(2)/CO_(2)adsorption tests were performed to evaluate the specifc surface area(SSA),pore size distribution(PSD),and pore volume(PV)using Braunuer-Emmett-Teller(BET),Barrett-Joyner-Halenda(BJH),and Density Functional Theory(DFT).The pore structure was characterized based on the theory of fractal dimensions.The results unveiled that the strength of coal has a signifcant infuence on pore structure and fractal dimensions.There are signifcant diferences in SSA and PV between both coals.The BJH-PV and BET-SSA obtained by N_(2)-adsorption for soft coal are 0.029–0.032 cm^(3)/g and 3.523–4.783 m^(2)/g.While the values of PV and SSA obtained by CO_(2)-adsorption are 0.037–0.039 cm^(3)/g and 106.016–111.870 m^(2)/g.Soft coal shows greater SSA and PV than hard coal,which is consistent with the adsorption capacity(VL).The fractal dimensions of soft and hard coal are respectively diferent.The Ding coal exhibits larger D1 and smaller D_(2),and the reverse for the Wu coal seam is observed.The greater the value of D1(complexity of pore surface)of soft coal is,the larger the pore surface roughness and gas adsorption capacity is.The results enable us to conclude that the characterization of pores and fractal dimensions of soft and hard coals is diferent,tending to diferent adsorption/desorption characteristics.In this regard,the results provide a reference for formulating corresponding coal and gas outburst prevention and control measures.

关键词： Methane adsorption Soft and hard coal Pore structure Fractal characteristics N_(2)/CO_(2)adsorption