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Event-based triggering mechanisms for nonlinear control systems

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Science China(Information Sciences) 2020年第5期63卷 119-130页

作者： yongfeng gao Ximing SUN Xian DU Wei WANG Key Laboratory of Intelligent Control and Optimization for Industrial Equipment of Ministry of Education Dalian University of Technology

This study examines triggered implementations of stabilizing controllers for general nonlinear systems. By using perturbation theory and Taylor's theorem, we propose new event-triggering and selftriggering mechanisms for general nonlinear control systems that are not necessarily input-to-state stable with respect to measurement errors. Both mechanisms are presented based on mild conditions and can ensure the uniform ultimate boundedness of the solutions of the resulting closed-loop control systems. The ultimate bounds can be made arbitrarily small by adjusting the design parameters. The effectiveness of the theoretical results is illustrated by simulations.

关键词： nonlinear systems triggered control sampled-data

Geochronology and Geochemistry of the Early Permian A-Type Granite in the Hongol Area, Central Inner Mongolia:Petrogenesis and Tectonic Implications

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Acta Geologica Sinica(English Edition) 2018年第3期92卷 988-1007页

作者： ZHANG Xiangxin gao yongfeng LEI Shihe College of Resource Science Hebei GEO University

We performed geochronological and geochemical analyses of the A-type granite in the Hongol area, central Inner Mongolia, to determine its age, petrogenesis and tectonic setting, which are significant for clarifying the Late Paleozoic tectonic evolution of the Xing’an Mongolian Orogenic Belt(XMOB). The rock type of the A-type granite in the Hongol area is alkali-feldspar granite, and it constitutes a western part of the Baiyinwula-Dongujimqin A-type granite belt. Zircon U-Pb geochronology yieldsPb/U ages ranging from 293 to 286 Ma for the alkali-feldspar granite, indicating this granitic pluton formed in the Early Permian. The alkali-feldspar granite is high in silica(SiO=75.13 wt%-80.17 wt%), aluminum(AlO=10.59 wt%-13.17 wt%) and alkali(NaO+KO=7.33 wt%-9.11 wt%), and low in MgO(0.08 wt%-0.39 wt%) and CaO(0.19 wt%-0.70 wt%). It is obviously enriched in LILEs such as Rb, Th and K,depleted in HFSEs such as Nb, Ti, La and Ce, with pronounced negative anomalies of Nb, Ti, P, Eu, Sr and Ba. Its Sr-Nd-Pb isotopic compositions show positive ε(t)(+0.72-+3.08), low T(805-997 Ma),and high radioactive Pb with(Pb/Pb)of 18.710-19.304,(Pb/Pb)of 15.557-15.604 and(Pb/Pb)of 37.887-38.330. Petrological characteristics and geochemical data suggest that the alkalifeldspar granite in the Hongol area belongs to aluminous A-type granite. This A-type granite formed in a post-collisional extensional setting and was generated by the partial melting of felsic rocks in the middlelower crust resulting from post-collisional slab breakoff. It is suggested that the Paleo-Asian Ocean was closed before the Permian in central Inner Mongolia.

关键词： aluminous A-type granite zircon U-Pb dating petrogenesis slab breakoff Xing'an Mongolian Orogenic Belt China

Zircon U-Pb Geochronology and Geochemistry of the Early Cretaceous Volcanic Rocks from the Manitu Formation in the Hongol Area, Northeastern Inner Mongolia

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Acta Geologica Sinica(English Edition) 2017年第4期91卷 1286-1304页

作者： ZHANG Xiangxin SU Zhen gao yongfeng College of Resource Science Hebei GEO University Shijiazhuang 050031 Hebei China

We undertook zircon U-Pb dating and geochemical analyses of volcanic rocks from the Manitu Formation in the Hongol area, northeastern Inner Mongolia, to determine their age, petrogenesis and sources, which are important for understanding the Late Mesozoic tectonic evolution of the Great Xing＇an Range. The volcanic rocks of the Manitu Formation from the Hongol area consist primarily of trachyandesite, based on their chemical compositions. The zircons from two of these trachyandesites are euhedral-subhedral in shape, display clear oscillatory growth zoning and have high Th/U ratios （0.31- 1.15）, indicating a magmatic origin. The results of LA-ICP-MS zircon U-Pb dating indicate that the volcanic rocks from the Manitu Formation in the Hongol area formed during the early Early Cretaceous with ages of 138.9-140.5 Ma. The volcanic rocks are high in alkali （Na2O ＋ K2O = 6.22-8.26 wt%）, potassium （K2O = 2.49-4.58 wt%） and aluminium （Al2O3 = 14.27-15.88 wt%）, whereas they are low in iron （total Fe2O3 = 3.76-6.53 wt%） and titanium （TiO2 = 1.02-1.61 wt%）. These volcanic rocks are obviously enriched in large ion lithophile elements, such as Rb, Ba, Th and U, and light rare earth elements, and are depleted in high field strength elements, such as Nb, Ta and Ti with pronounced negative anomalies. Their Sr-Nd-Pb isotopic compositions show positive εNd（t）（＋0.16%o t0＋1.64%o） and low TDM（t）（694--767 Ma）. The geochemical characteristics of these volcanic rocks suggest that they belong to a shoshonitic series and were likely generated from the partial melting of an enriched lithospheric mantle that was metasomatised by fluids released from a subducted slab during the closure of the Mongol- Okhotsk Ocean. Elemental and isotopic features reveal that fractional crystallization with the removal of ferromagnesian minerals, plagioclase, ilmenite, magnetite and apatite played an important role during the evolution of the magma. These shoshonitic rocks were produced by the partial melting of

关键词： shoshonitic rocks Manitu Formation geochronology geochemistry northeastern Inner Mongolia

Zircon U-Pb Ages of the Chagangnuer Mafic Intrusion in Central Inner Mongolia and their Tectonic Implications

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Acta Geologica Sinica(English Edition) 2019年第3期93卷 771-773页

作者： ZHANG Xiangxin gao yongfeng LEI Shihe Key Laboratory of Regional Geology and Mineralization Hebei GEO UniversityShijiazhuang 050031China College of Resource Science Hebei GEO UniversityShijiazhuang 050031China

The Central Asian Orogenic Belt(CAOB)is regarded as the world's largest and long-lived Phanerozoic accretionary orogen,which has recorded a long history of multiple subduction-accretion events during the Neoproterozoic to *** CAOB was formed by the progressive subduction of the Paleo-Asian Ocean(PAO).However,the final closure time of the PAO is still controversial,ranging from the Late Devonian to the Early-Middle Triassic(Zhang et al.,2018).

关键词： Zircon U-Pb Ages Tectonic Implications

Energy enhanced tissue texture in spectral computed tomography for lesion classification

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Visual Computing for Industry,Biomedicine,and Art 2019年第1期2卷 138-149页

作者： yongfeng gao Yongyi Shi Weiguo Cao Shu Zhang Zhengrong Liang Department of Radiology Stony Brook UniversityStony BrookNY 11794USA Institute of Image Processing and Pattern Recognition Xi’an Jiaotong UniversityXi’an 710049ShanxiChina Departments of Radiology Biomedical EngineeringComputer Scienceand Electrical EngineeringStony Brook UniversityStony BrookNY 11794USA

Tissue texture reflects the spatial distribution of contrasts of image voxel gray levels,i.e.,the tissue heterogeneity,and has been recognized as important biomarkers in various clinical *** computed tomography(CT)is believed to be able to enrich tissue texture by providing different voxel contrast images using different X-ray ***,this paper aims to address two related issues for clinical usage of spectral CT,especially the photon counting CT(PCCT):(1)texture enhancement by spectral CT image reconstruction,and(2)spectral energy enriched tissue texture for improved lesion *** issue(1),we recently proposed a tissue-specific texture prior in addition to low rank prior for the individual energy-channel low-count image reconstruction problems in PCCT under the Bayesian *** results showed the proposed method outperforms existing methods of total variation(TV),low-rank TV and tensor dictionary learning in terms of not only preserving texture features but also suppressing image *** issue(2),this paper will investigate three models to incorporate the enriched texture by PCCT in accordance with three types of inputs:one is the spectral images,another is the cooccurrence matrices(CMs)extracted from the spectral images,and the third one is the Haralick features(HF)extracted from the *** were performed on simulated photon counting data by introducing attenuationenergy response curve to the traditional CT images from energy integration *** results showed the spectral CT enriched texture model can improve the area under the receiver operating characteristic curve(AUC)score by 7.3%,0.42%and 3.0%for the spectral images,CMs and HFs respectively on the five-energy spectral data over the original single energy data *** CM-and HF-inputs can achieve the best AUC of 0.934 and *** texture themed study shows the insight that incorporating clinical important prior information,e.g.,tiss

关键词： Tissue texture Spectral computed tomography Lesion classification Machine learning Bayesian reconstruction

Improved computer-aided detection of pulmonary nodules via deep learning in the sinogram domain

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Visual Computing for Industry,Biomedicine,and Art 2019年第1期2卷 129-137页

作者： yongfeng gao Jiaxing Tan Zhengrong Liang Lihong Li Yumei Huo Department of Radiology State University of New YorkStony BrookNY 11794USA Departments of Computer Science City University of New York/CSIStaten IslandNY 10314USA Engineering and Environmental Science City University of New York/CSIStaten IslandNY 10314USA

Computer aided detection(CADe)of pulmonary nodules plays an important role in assisting radiologists’diagnosis and alleviating interpretation burden for lung *** CADe systems,aiming at simulating radiologists’examination procedure,are built upon computer tomography(CT)images with feature extraction for detection and *** visual perception in CT image is reconstructed from sinogram,which is the original raw data acquired from CT *** this work,different from the conventional image based CADe system,we propose a novel sinogram based CADe system in which the full projection information is used to explore additional effective features of nodules in the sinogram *** the challenges of limited research in this concept and unknown effective features in the sinogram domain,we design a new CADe system that utilizes the self-learning power of the convolutional neural network to learn and extract effective features from *** proposed system was validated on 208 patient cases from the publicly available online Lung Image Database Consortium database,with each case having at least one juxtapleural nodule *** results demonstrated that our proposed method obtained a value of 0.91 of the area under the curve(AUC)of receiver operating characteristic based on sinogram alone,comparing to 0.89 based on CT image ***,a combination of sinogram and CT image could further improve the value of AUC to *** study indicates that pulmonary nodule detection in the sinogram domain is feasible with deep learning.

关键词： Computer-aided detection Computed tomography Deep learning Lung Sinogram

Stimuli-responsive polymeric materials for human health applications

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Chinese Science Bulletin 2014年第32期59卷 4237-4255页

作者： Molla R.Islam yongfeng gao Xue Li Qiang Matthew Zhang Menglian Wei Michael J.Serpe Department of Chemistry University of Alberta Edmonton AB T6G 2G2 Canada

Stimuli-responsive polymers have the extraordinary ability to change their physical and/or chemical state after they‘‘detect’’a change in their environment;their response depends dramatically on their chemical *** property has been used for a plethora of applications;this review highlights their utility for human ***,this review will highlight efforts in the areas of sensing and biosensing,antimicrobial/antifouling coatings,tissue engineering and regenerative medicine,and drug *** examples are given in each of these areas,with some focus on our work engineering poly(Nisopropylacrylamide)-based microgels and other responsive systems.

关键词：聚合物材料刺激响应性人体健康应用 N-异丙基丙烯酰胺化学状态生物传感组织工程

Multi-scale characterizations of colon polyps via computed tomographic colonography

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Visual Computing for Industry,Biomedicine,and Art 2019年第1期2卷 245-256页

作者： Weiguo Cao Marc J.Pomeroy yongfeng gao Matthew A.Barish Almas F.Abbasi Perry J.Pickhardt Zhengrong Liang The Department of Radiology Stony Brook UniversityStony BrookNY 11794USA The Departments of Radiology and Biomedical Engineering Stony Brook UniversityStony BrookNY 11794USA The Department of Radiology School of MedicineUniversity of WisconsinMadisonWI 53792USA

Texture features have played an essential role in the field of medical imaging for computer-aided *** gray-level co-occurrence matrix(GLCM)-based texture descriptor has emerged to become one of the most successful feature sets for these *** study aims to increase the potential of these features by introducing multi-scale analysis into the construction of GLCM texture *** this study,we first introduce a new parameter-stride,to explore the definition of *** we propose three multi-scaling GLCM models according to its three parameters,(1)learning model by multiple displacements,(2)learning model by multiple strides(LMS),and(3)learning model by multiple *** models increase the texture information by introducing more texture patterns and mitigate direction sparsity and dense sampling problems presented in the traditional Haralick *** further analyze the three parameters,we test the three models by performing classification on a dataset of 63 large polyp masses obtained from computed tomography colonoscopy consisting of 32 adenocarcinomas and 31 benign ***,the proposed methods are compared to several typical GLCM-texture descriptors and one deep learning *** obtains the highest performance and enhances the prediction power to 0.9450 with standard deviation 0.0285 by area under the curve of receiver operating characteristics score which is a significant improvement.

关键词： Colon cancer Computed tomographic colonography Polyp characterization Texture feature

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基于自映像的光子晶体波导分束器的设计

强激光与粒子束 2010年第9期22卷 2160-2164页

作者：高永锋周骏江苏大学机械工程学院光信息科学与技术系江苏镇江212013 宁波大学理学院物理系浙江宁波315211

通过研究2维正方晶格光子晶体波导多模干涉的自映像效应,优化设计了一种新型1×2光子晶体波导分束器,采用时域有限差分法对其传输特性进行模拟分析。设计过程中,根据多模干涉耦合区中周期出现的双重像的位置确定两个单模输出波导的位置... 详细信息

通过研究2维正方晶格光子晶体波导多模干涉的自映像效应,优化设计了一种新型1×2光子晶体波导分束器,采用时域有限差分法对其传输特性进行模拟分析。设计过程中,根据多模干涉耦合区中周期出现的双重像的位置确定两个单模输出波导的位置,通过在分束器输入和输出耦合区的连结处设置介质柱,改变输入和输出耦合区中的模场分布,实现模式匹配,从而明显减小分束器的反射损耗。计算结果表明:设置的介质柱归一化半径分别为0.08和0.177时,对于波长为1.55μm的入射光,该分束器的透射率可高达93%。

关键词：光子晶体波导自成像效应多模干涉模式匹配分束器