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Toward an integrated framework for geosensor grid

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International Journal of Digital Earth 2010年第2期3卷 207-216页

作者： Zhou huang Yu fang Mao Pan Institute of Remote Sensing&GIS Peking UniversityBeijingP.R.China Key Laboratory of Orogenic Belts and Crustal Evolution Ministry of EducationPeking UniversityBeijingP.R.China

Grid computing is deemed as a good solution to the digital earth *** geographically dispersed geospatial resources can be connected and merged into a‘supercomputer’by using the grid-computing *** the other side,geosensor networks offer a new perspective for collecting physical data dynamically and modeling a real-time virtual *** geosensor networks and grid computing in geosensor grid can be compared to equipping the geospatial information grid with‘eyes’and‘ears.’Thus,real-time information in the physical world can be processed,correlated,and modeled to enable complex and advanced geospatial analyses on geosensor grid with capability of high-performance *** are several issues and challenges that need to be overcome before geosensor grid comes *** this paper,we propose an integrated framework,comprising the geosensor network layer,the grid layer and the application layer,to address these design *** technologies of the geosensor grid framework are ***,a geosensor grid testbed is set up to illustrate the proposed framework and improve our geosensor grid design.

关键词： geosensor networks grid computing digital earth GIS supercomputer

Sequential clustering of star formations in IC 1396

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Research in Astronomy and Astrophysics 2013年第5期13卷 557-570页

作者： Ya-fang huang Jin-Zeng Li National Astronomical Observatories Chinese Academy of Sciences

We present a comprehensive study of the H II region IC 1396 and its star forming activity, in which multi-wavelength data ranging from the optical to the near- and far-infrared were employed. The surface density distribution of all the 2MASS sources with a certain detection toward IC 1396 indicates the existence of a compact cluster spatially consistent with the position of the exciting source of the H II region, HD 206267. The spatial distribution of the sources with excessive infrared emission, selected based on archived 2MASS data, reveals the existence of four sub-clusters in this region. One is associated with the open cluster Trumpler 37. The other three are found to be spatially coincident with the bright rims of the H II region. All the sources with excessive emission in the near infrared are cross-identified with AKARI IRC data. An analysis of the spectral energy distributions （SEDs） of the resultant sample leads to the identification of eight CLASS I, 15 CLASS II and 15 CLASS IH sources in IC 1396. Optical identification of the sample sources with R magnitudes brighter than 17 mag corroborates the results from the SED analysis. Based on the spatial distribution of the infrared young stellar objects at different evolutionary stages, the surrounding sub-clusters located in the bright rims are believed to be younger than the central one. This is consistent with a scenario of sequential star formation in this region. Imaging data of a dark patch in IC 1396 by Herschel SPIRE, on the other hand, indicate the presence of two far-infrared cores in LDN 1111, which are likely to be a new generation of protostellar objects in formation. So we infer that the star formation process in this H II region was not continuous but rather episodic.

关键词： techniques: photometric -- stars: formation -- stars: pre-main sequence-- infrared: stars

On structure of cluster algebras of geometric type Ⅰ：In view of sub-seeds and seed homomorphisms

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Science China Mathematics 2018年第5期61卷 831-854页

作者： Min huang fang Li Yichao Yang Department of Mathematics Zhejiang University Hangzhou 310027 China Departement de Mathematiques Universite de Sherbrooke Sherbrooke J1K2R1 Canada

Our motivation is to build a systematic method in order to investigate the structure of cluster algebras of geometric type. The method is given through the notion of mixing-type sub-seeds, the theory of seed homomorphisms and the view-point of gluing of seeds. As an application, for(rooted) cluster algebras, we completely classify rooted cluster subalgebras and characterize rooted cluster quotient algebras in detail. Also,we build the relationship between the categorification of a rooted cluster algebra and that of its rooted cluster subalgebras. Note that cluster algebras of geometric type studied here are of the sign-skew-symmetric case.

关键词： seed homomorphism mixing-type sub-seed rooted cluster morphism sub-rooted cluster algebra rooted cluster quotient algebra

Averaged NmF2 of cusp-latitude ionosphere in northern hemisphere for solar minimum—Comparison between modeling and ESR during IPY

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Science China(Technological Sciences) 2012年第5期55卷 1281-1286页

作者： HE fang ZHANG BeiChen huang DeHong SOA Key LaboratoryJbr Polar Science Polar Research Institute of ChinaShanghai 200136China

Based on the ionosphere observation data obtained by EISCAT Svalbard Radar (ESR) in solar minimum year-2007, we analyzed diurnal variations of F2-peak electron density (NmF2) in four seasons under disturbed and quiet geomagnetic conditions. It indicated that the soft precipitation electron had an evident effect on the NmF2 increase at magnetic noon in spring, summer and autumn and the electron precipitation effects were prominent in winter. The comparison between the IRI-2007 model and the observation exhibited that the IRI (International Reference Ionosphere) model had a better NmF2 prediction when the photoionization was dominant during the polar day, but worse when the electron precipitation was dominant during the polar night. We showed that the electrons in lower energy band decreased when the geomagnetic disturbance went greater, which resulted in the lower NmF2. By analyzing the spectrum of precipitation electron under different geomagnetic conditions, it was found that this phenomenon was induced by the energy flux enhancement of precipitation electron of low energy.

关键词： electron density solar minimum electron precipitation IRI model

Existence of Solutions to Generalized Vector Quasi-Equilibrium Problems with Discontinuous Mappings

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Acta Mathematica Sinica,English Series 2006年第4期22卷 1127-1132页

作者： Ya Ping fang Nan Jing huang Department of Mathematics Sichuan University Chengdu 610064 P. R. China

Let X, Y be two finite-dimensional topological vector spaces, Z a Hausdorff topological vector space, K C X and D C Z be two nonempty sets, C be a pointed, closed, and convex cone in Y with int C ≠θ Let S ： K → 2^K and T ： K → 2^D be two multivalued mappings, and φ ： K × D × K → Y be a trifunction. In this paper, we consider the generalized vector quasi-equilibrium problem, which is formulated by finding X∈ K and y∈ T（x） such that x∈ E S（x） and φ（x,y, u）（∈/） -int C for all u ∈ S（x）. We establish an existence result in which T is not supposed to have any continuity property. Our results extend and improve the corresponding results of Cubiotti, Yao and Guo.

关键词： Generalized vector quasi-equilibrium problem Upper semi-continuity Lower semi-continuity Fixed point Existence

Multi-objective optimization strategy for distribution network considering V2Genabled electric vehicles in building integrated energy system

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Protection and Control of Modern Power Systems 2020年第1期5卷 48-55页

作者： Zhao huang Baling fang Jin Deng Hunan college of information ChangshaChina College of electric and information engineering Hunan university of technologyZhuzhouChina

Based on the large-scale penetration of electric vehicles(EV)into the building cluster,a multi-objective optimal strategy considering the coordinated dispatch of EV is proposed,for improving the safe and economical operation problems of distribution *** system power loss and node voltage excursion can be effectively reduced,by taking measures of time-of-use(TOU)price mechanism bonded with the reactive compensation of energy storage ***,the coordinate charging/discharging load model for EV has been established,to obtain a narrowed gap between load peak and ***,a multi-objective optimization model of the distribution grid is also defined,and the active power loss and node voltage fluctuation are chosen to be the objective *** improving the efficiency of optimization process,an advanced genetic algorithm associated with elite preservation policy is ***,reactive compensation capacity supplied by capacitor banks is dynamically determined according to the varying building *** proposed strategy is demonstrated on the IEEE 33-node test case,and the simulation results show that the power supply pressure can be obviously relieved by introducing the coordinated charging/discharging behavior of EV;in the meantime,via reasonable planning of the compensation capacitor,the remarkably lower active power loss and voltage excursion can be realized,ensuring the safe and economical operation of the distribution system.

关键词： Distribution network Electric vehicles Multi-objective optimization Coordinated dispatch Advanced genetic algorithm

Nitrogen addition promotes soil carbon accumulation globally

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Science China Life Sciences 2025年第1期 284-293页

作者： Xuemei Yang Suhui Ma Erhan huang Danhua Zhang Guoping Chen Jiangling Zhu Chengjun Ji Biao Zhu Lingli Liu Jingyun fang Institute of Ecology College of Urban and Environmental Sciencesand Key Laboratory for Earth Surface Processes of the Ministry of EducationPeking University Ministry of Education Key Laboratory for Transboundary Ecosecurity of Southwest China School of Ecology and Environmental ScienceYunnan University State Key Laboratory of Vegetation and Environmental Change Institute of BotanyChinese Academy of Sciences

Soil is the largest carbon(C) reservoir in terrestrial ecosystems and plays a crucial role in regulating the global C cycle and climate *** nitrogen(N) deposition has been widely considered as a critical factor affecting soil organic carbon(SOC) storage, but its effect on SOC components with different stability remains unclear. Here, we analyzed extensive empirical data from 304 sites worldwide to investigate how SOC and its components respond to N addition. Our analysis showed that N addition led to a significant increase in bulk SOC(6.7%), with greater increases in croplands(10.6%) and forests(6.0%) compared to grasslands(2.1%). Regarding SOC components, N addition promoted the accumulation of plant-derived C(9.7%–28.5%) over microbial-derived C(0.2%), as well as labile(5.7%) over recalcitrant components(–1.2%), resulting in a shift towards increased accumulation of plant-derived labile C. Consistently, N addition led to a greater increase in particulate organic C(11.9%) than mineral-associated organic C(3.6%), suggesting that N addition promotes C accumulation across all pools, with more increase in unstable than stable pools. The responses of SOC and its components were best predicted by the N addition rate and net primary productivity. Overall, our findings suggest that N enrichment could promote the accumulation of plant-derived and non-mineral associated C and a subsequent decrease in the overall stability of soil C pool, which underscores the importance of considering the effects of N enrichment on SOC components for a better understanding of C dynamics in soils.

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CFD predictions of LBO limits for aero-engine combustors using fuel iterative approximation

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Chinese Journal of Aeronautics 2013年第1期26卷 74-84页

作者： Hu Bin huang Yong Wang fang Xie Fa Key Laboratory of Light-duty Gas-turbine Institute of Engineering Thermophysics Chinese Academy of Sciences AEL Key Laboratory of Science and Technology for National Defence School of Energy and Power EngineeringBeihang University

Lean blow-out （LBO） is critical to operational performance of combustion systems in propulsion and power generation. Current predictive tools for LBO limits are based on decadesold empirical correlations that have limited applicability for modern combustor designs. According to the Lefebvre＇s model for LBO and classical perfect stirred reactor （PSR） concept, a load parameter （LP） is proposed for LBO analysis of aero-engine combustors in this paper. The parameters contained in load parameter are all estimated from the non-reacting flow field of a combustor that is obtained by numerical simulation. Additionally, based on the load parameter, a method of fuel iterative approximation （FIA） is proposed to predict the LBO limit of the combustor. Compared with experimental data for 19 combustors, it is found that load parameter can represent the actual combustion load of the combustor near LBO and have good relativity with LBO fuel/air ratio （FAR）. The LBO FAR obtained by FIA shows good agreement with experimental data, the maximum prediction uncertainty of FIA is about ±17.5%. Because only the non-reacting flow is simulated, the time cost of the LBO limit prediction using FIA is relatively low （about 6 h for one combustor with computer equipment of CPU 2.66 GHz · 4 and 4 GB memory）, showing that FIA is reliable and efficient to be used for practical applications.

关键词： Aero-engine combustor Computational fluid dynamics Fuel iterative approximation LBO limits prediction Perfect stirred reactor

On extended state based Kalman filter design for a class of nonlinear time-varying uncertain systems

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Science China(Information Sciences) 2018年第4期61卷 118-133页

作者： Wenyan BAI Wenchao XUE Yi huang Haitao fang Beijing Aerospace Automatic Control Institute LSC NCMIS Academy of Mathematics and Systems Science Chinese Academy of Sciences School of Mathematical Sciences University of Chinese Academy of Sciences

This paper considers the filtering problem for a class of multi-input multi-output systems with nonlinear time-varying uncertain dynamics, random process and measurement noise. An extended state based Kalman filter, with the idea of timely estimating the unknown dynamics, is proposed for better robustness and higher estimation precision. The stability of the proposed filter is rigorously proved for nonlinear timevarying uncertain system with weaker stability condition than the extended Kalman filter, i.e., the initial estimation error, the uncertain dynamics and the noises are only required to be bounded rather than small enough. Moreover, quantitative precision of the proposed filter is theoretically evaluated. The proposed algorithm is proved to be the asymptotic unbiased minimum variance filter for constant uncertainty. The simulation results of some benchmark examples demonstrate the feasibility and effectiveness of the method.

关键词： Kalman filter extended state observer nonlinear time-varying uncertain system unbiased minimum variance filter active disturbance rejection control