期刊文献+
共找到9,625篇文章
< 1 2 250 >
每页显示 20 50 100
Solid Waste Management:A MADM Approach Using Fuzzy Parameterized Possibility Single-Valued Neutrosophic Hypersoft Expert Settings
1
作者 Tmader Alballa Muhammad Ihsan +2 位作者 Atiqe Ur Rahman Noorah Ayed Alsorayea Hamiden Abd El-Wahed Khalifa 《Computer Modeling in Engineering & Sciences》 SCIE EI 2025年第1期531-553,共23页
The dramatic rise in the number of people living in cities has made many environmental and social problems worse.The search for a productive method for disposing of solid waste is the most notable of these problems.Ma... The dramatic rise in the number of people living in cities has made many environmental and social problems worse.The search for a productive method for disposing of solid waste is the most notable of these problems.Many scholars have referred to it as a fuzzy multi-attribute or multi-criteria decision-making problem using various fuzzy set-like approaches because of the inclusion of criteria and anticipated ambiguity.The goal of the current study is to use an innovative methodology to address the expected uncertainties in the problem of solid waste site selection.The characteristics(or sub-attributes)that decision-makers select and the degree of approximation they accept for various options can both be indicators of these uncertainties.To tackle these problems,a novel mathematical structure known as the fuzzy parameterized possibility single valued neutrosophic hypersoft expert set(ρˆ-set),which is initially described,is integrated with a modified version of Sanchez’s method.Following this,an intelligent algorithm is suggested.The steps of the suggested algorithm are explained with an example that explains itself.The compatibility of solid waste management sites and systems is discussed,and rankings are established along with detailed justifications for their viability.This study’s strengths lie in its application of fuzzy parameterization and possibility grading to effectively handle the uncertainties embodied in the parameters’nature and alternative approximations,respectively.It uses specific mathematical formulations to compute the fuzzy parameterized degrees and possibility grades that are missing from the prior literature.It is simpler for the decisionmakers to look at each option separately because the decision is uncertain.Comparing the computed results,it is discovered that they are consistent and dependable because of their preferred properties. 展开更多
关键词 Hypersoft expert set Sanchez’s method decision making optimization solid waste management possibility grade fuzzy parameterization
在线阅读 下载PDF
A lung cancer early-warning risk model based on facial diagnosis image features
2
作者 Yulin SHI Shuyi ZHANG +4 位作者 Jiayi LIU Wenlian CHEN Lingshuang LIU Ling XU Jiatuo XU 《Digital Chinese Medicine》 2025年第3期351-362,共12页
Objective To explore the feasibility of constructing a lung cancer early-warning risk model based on facial image features,providing novel insights into the early screening of lung cancer.Methods This study included p... Objective To explore the feasibility of constructing a lung cancer early-warning risk model based on facial image features,providing novel insights into the early screening of lung cancer.Methods This study included patients with pulmonary nodules diagnosed at the Physical Examination Center of Shuguang Hospital Affiliated to Shanghai University of Traditional Chinese Medicine from November 1,2019 to December 31,2024,as well as patients with lung cancer diagnosed in the Oncology Departments of Yueyang Hospital of Integrated Traditional Chinese and Western Medicine and Longhua Hospital during the same period.The facial image information of patients with pulmonary nodules and lung cancer was collected using the TFDA-1 tongue and facial diagnosis instrument,and the facial diagnosis features were extracted from it by deep learning technology.Statistical analysis was conducted on the objective facial diagnosis characteristics of the two groups of participants to explore the differences in their facial image characteristics,and the least absolute shrinkage and selection operator(LASSO)regression was used to screen the characteristic variables.Based on the screened feature variables,four machine learning methods:random forest,logistic regression,support vector machine(SVM),and gradient boosting decision tree(GBDT)were used to establish lung cancer classification models independently.Meanwhile,the model performance was evaluated by indicators such as sensitivity,specificity,F1 score,precision,accuracy,the area under the receiver operating characteristic(ROC)curve(AUC),and the area under the precision-recall curve(AP).Results A total of 1275 patients with pulmonary nodules and 1623 patients with lung cancer were included in this study.After propensity score matching(PSM)to adjust for gender and age,535 patients were finally included in the pulmonary nodule group and the lung cancer group,respectively.There were significant differences in multiple color space metrics(such as R,G,B,V,L,a,b,Cr,H,Y,and Cb)and texture metrics[such as gray-levcl co-occurrence matrix(GLCM)-contrast(CON)and GLCM-inverse different moment(IDM)]between the two groups of individuals with pulmonary nodules and lung cancer(P<0.05).To construct a classification model,LASSO regression was used to select 63 key features from the initial 136 facial features.Based on this feature set,the SVM model demonstrated the best performance after 10-fold stratified cross-validation.The model achieved an average AUC of 0.8729 and average accuracy of 0.7990 on the internal test set.Further validation on an independent test set confirmed the model’s robust performance(AUC=0.8233,accuracy=0.7290),indicating its good generalization ability.Feature importance analysis demonstrated that color space indicators and the whole/lip Cr components(including color-B-0,wholecolor-Cr,and lipcolor-Cr)were the core factors in the model’s classification decisions,while texture indicators[GLCM-angular second moment(ASM)_2,GLCM-IDM_1,GLCM-CON_1,GLCM-entropy(ENT)_2]played an important auxiliary role.Conclusion The facial image features of patients with lung cancer and pulmonary nodules show significant differences in color and texture characteristics in multiple areas.The various models constructed based on facial image features all demonstrate good performance,indicating that facial image features can serve as potential biomarkers for lung cancer risk prediction,providing a non-invasive and feasible new approach for early lung cancer screening. 展开更多
关键词 INSPECTION Facial features Lung cancer early-warning risk Machine learning
暂未订购
Elephant Early-warning System in China:Leveraging Information Superiority to Mitigate Human-elephant Conflict
3
作者 DENG Yun YUAN Shengdong +6 位作者 DENG Xiaobao CHEN Hui LI Zhongyuan GUO Xianming WANG Bin Ahimsa Campos-Arceiz LIN Luxiang 《Bulletin of the Chinese Academy of Sciences》 2025年第3期178-186,共9页
Human-elephant conflict(HEC)poses a major socio-ecological challenge across elephant range states.Since 2015,the National Forest Ecosystem Research Station of China based in Xishuangbanna has developed the Elephant Ea... Human-elephant conflict(HEC)poses a major socio-ecological challenge across elephant range states.Since 2015,the National Forest Ecosystem Research Station of China based in Xishuangbanna has developed the Elephant Early-warning System(EEWS),a novel approach that has demonstrably reduced the risk of HEC incidents-particularly those involving direct encounters between people and elephants.By dynamically maintaining safety buffers,this system safeguards endangered elephants while mitigating human safety risks during livelihood activities and ensuring uninterrupted elephant movement.Building upon the C4ISR framework(Command,Control,Communications,Computers,Intelligence,Surveillance,and Reconnaissance),EEWS integrates key technological and institutional innovations-including the widespread adoption of mobile internet,deployment of camera traps,use of drones,and cross-sectoral governance reforms.The EEWS’s conceptual framework and technical architecture have been already recognized by local government and are now being scaled up from Xishuangbanna to the entire Asian elephant range in China,establishing a replicable“China model”for achieving harmonious human-elephant coexistence.This study reviews the conceptual foundations,development,and field implementation of EEWS,and offers recommendations to guide future refinement and broader application. 展开更多
关键词 human-elephant conflict Elephant early-warning System C4ISR framework social governance
在线阅读 下载PDF
Parameterized Littlewood-Paley Operators and Their Commutators on Two-Weight Grand Homogeneous Variable Herz-Morrey Spaces
4
作者 Xijuan CHEN Wenwen TAO Guanghui LU 《Journal of Mathematical Research with Applications》 2025年第2期231-242,共12页
In this paper,the authors prove that the parameterized area integralμ_(Ω,S)^(ρ)and the parameterized Littlewood-Paley g_(δ)^(*)-functionμ_(Ω,δ)^(*,ρ)are bounded on two-weight grand homogeneous variable Herz-Mo... In this paper,the authors prove that the parameterized area integralμ_(Ω,S)^(ρ)and the parameterized Littlewood-Paley g_(δ)^(*)-functionμ_(Ω,δ)^(*,ρ)are bounded on two-weight grand homogeneous variable Herz-Morrey spaces MK_(p),θ,q(·))^(α(·),λ)(ω_(1),ω_(2)),where θ>0,λ∈(2,∞),q(·)∈B(R^(n)),α(·)∈L^(∞)(R^(n)),ω_(1)∈A_(p_(ω_(1)))for p_(ω_(1))∈[1,∞]and ω_(2) is a weight.Furthermore,the authors prove that the commutators[b,μ_(Ω,S)^(ρ)]which is formed by b∈BMO(R^(n))and the μ_(Ω,S)^(ρ),and the[b,μ_(Ω,δ)^(*,ρ)]generated by b∈BMO(R^(n))and theμ_(Ω,δ)^(*,ρ)are bounded on MK_(p),θ,q(·))^(α(·),λ)(ω_(1),ω_(2)),respectively. 展开更多
关键词 Grand homogeneous variable Herz-Morrey space parameterized area integral parameterized Littlewood-Paley g_(δ)^(*)-function commutator space BMO(R^(n))
原文传递
A body-fitted adaptive mesh and Helmholtz-type filter based parameterized level-set method for structural topology optimization
5
作者 Yijie Lu Xueying Chang +3 位作者 Zhengwei Zhang Hui Liu Yanguo Zhou Hao Li 《Acta Mechanica Sinica》 2025年第5期131-147,共17页
Parameterized level-set method(PLSM)has been proposed and developed for many years,and is renowned for its efficacy in ad-dressing topology optimization challenges associated with intricate boundaries and nucleation o... Parameterized level-set method(PLSM)has been proposed and developed for many years,and is renowned for its efficacy in ad-dressing topology optimization challenges associated with intricate boundaries and nucleation of new holes.However,most pertinent investigations in the field rely predominantly on fixed background mesh,which is never remeshed.Consequently,the mesh element partitioned by material interface during the optimization process necessitates approximation by using artificial interpolation models to obtain its element stiffness or other properties.This paper introduces a novel approach to topology op-timization by integrating the PLSM with body-fitted adaptive mesh and Helmholtz-type filter.Primarily,combining the PLSM with body-fitted adaptive mesh enables the regeneration of mesh based on the zero level-set interface.This not only precludes the direct traversal of the material interface through the mesh element during the topology optimization process,but also improves the accuracy of calculation.Additionally,the incorporation of a Helmholtz-type partial differential equation filter,relying solely on mesh information essential for finite element discretization,serves to regulate the topological complexity and the minimum feature size of the optimized structure.Leveraging these advantages,the topology optimization program demonstrates its versa-tility by successfully addressing various design problems,encompassing the minimum mean compliance problem and minimum energy dissipation problem.Ultimately,the result of numerical example indicates that the optimized structure exhibits a dis-tinct and smooth boundary,affirming the effective control over both topological complexity and the minimum feature size of the optimized structure. 展开更多
关键词 Topology optimization parameterized level-set method Helmholtz-type filter Body-fitted adaptive mesh
原文传递
Typhoon Kompasu(2118)simulation with planetary boundary layer and cloud physics parameterization improvements
6
作者 Xiaowei Tan Zhiqiu Gao Yubin Li 《Atmospheric and Oceanic Science Letters》 2026年第1期41-46,共6页
This study introduces a new ocean surface friction velocity scheme and a modified Thompson cloud microphysics parameterization scheme into the CMA-TYM model.The impact of these two parameterization schemes on the pred... This study introduces a new ocean surface friction velocity scheme and a modified Thompson cloud microphysics parameterization scheme into the CMA-TYM model.The impact of these two parameterization schemes on the prediction of the movement track and intensity of Typhoon Kompasu in 2021 is examined.Additionally,the possible reasons for their effects on tropical cyclone(TC)intensity prediction are analyzed.Statistical results show that both parameterization schemes improve the predictions of Typhoon Kompasu’s track and intensity.The influence on track prediction becomes evident after 60 h of model integration,while the significant positive impact on intensity prediction is observed after 66 h.Further analysis reveals that these two schemes affect the timing and magnitude of extreme TC intensity values by influencing the evolution of the TC’s warm-core structure. 展开更多
关键词 Tropical cyclone Numerical simulation Planetary boundary layer parameterization SCHEME Cloud physics scheme
在线阅读 下载PDF
Construction of Early-warning Model for Plant Diseases and Pests Based on Improved Neural Network 被引量:2
7
作者 曹志勇 邱靖 +1 位作者 曹志娟 杨毅 《Agricultural Science & Technology》 CAS 2009年第6期135-137,154,共4页
By studying principles and methods related to early-warning model of plant diseases and using PSO method, parameter optimization was conducted to backward propagation neural network, and a pre-warning model for plant ... By studying principles and methods related to early-warning model of plant diseases and using PSO method, parameter optimization was conducted to backward propagation neural network, and a pre-warning model for plant diseases based on particle swarm and neural network algorithm was established. The test results showed that the construction of early-warning model is effective and feasible, which will provide a via- ble model structure to establish the effective early-warning platform. 展开更多
关键词 Backward propagation neural network Particle swarm algorithm Plant diseases and pests early-warning model
在线阅读 下载PDF
PARAMETERIZED-PROTOTYPE-BASED DYNAMIC OPTIMIZATION DESIGN FOR CAM PROFILE 被引量:1
8
作者 彭禹 郝志勇 《Transactions of Nanjing University of Aeronautics and Astronautics》 EI 2007年第4期310-316,共7页
Aiming at the problems in current cam profile optimization processes, such as simple dynamics models, limited geometric accuracy and low design automatization level, a new dynamic optimization mode is put forward. Bas... Aiming at the problems in current cam profile optimization processes, such as simple dynamics models, limited geometric accuracy and low design automatization level, a new dynamic optimization mode is put forward. Based on the parameterization modeling technique of MSC. ADAMS platform, the different steps in current mode are reorganized, thus obtaining an upgraded mode called the "parameterized-prototype-based cam profile dynamic optimization mode". A parameterized prototype(PP) of valve mechanism is constructed in the course of dynamic optimization for cam profiles. Practically, by utilizing PP and considering the flexibility of the parts in valve mechanism, geometric accuracy and design automatization are improved. 展开更多
关键词 valve mechanism cam profile optimization design parameterized prototype dynamic optimization
在线阅读 下载PDF
Control-oriented Modeling for Air-breathing Hypersonic Vehicle Using Parameterized Configuration Approach 被引量:31
9
作者 LI Huifeng LIN Ping XU Dajun 《Chinese Journal of Aeronautics》 SCIE EI CAS CSCD 2011年第1期81-89,共9页
This article presents a parameterized configuration modeling approach to develop a 6 degrees of freedom (DOF) rigid-body model for air-breathing hypersonic vehicle (AHV). The modeling process involves the paramete... This article presents a parameterized configuration modeling approach to develop a 6 degrees of freedom (DOF) rigid-body model for air-breathing hypersonic vehicle (AHV). The modeling process involves the parameterized configuration design, inviscous hypersonic aerodynamic force calculation and scramjet engine modeling. The parameters are designed for airframe-propulsion integration configuration, the aerodynamic force calculation is based on engineering experimental methods, and the engine model is acquired from gas dynamics and quasi-one dimensional combustor calculations. Multivariate fitting is used to obtain analytical equations for aerodynamic force and thrust. Furthermore, the fitting accuracy is evaluated by relative error (RE). Trim results show that the model can be applied to the investigation of control method for AHV during the cruise phase. The modeling process integrates several disciplines such as configuration design, aerodynamic calculation, scramjet modeling and control method. Therefore the modeling method makes it possible to conduct AHV aerodynamics/propulsion/control integration design. 展开更多
关键词 flight dynamics HYPERSONIC AHV model parameterized configuration design aerodynamics/propulsion integration
原文传递
Deformation early-warning index for heightened gravity dam during impoundment period 被引量:11
10
作者 Bo Chen Zi-shen Huang +1 位作者 Teng-fei Bao Zheng Zhu 《Water Science and Engineering》 EI CAS CSCD 2021年第1期54-64,共11页
The mechanical parameters of materials in a dam body and dam foundation tend to change when dams are reinforced in aging processes.It is important to use an early-warning index to reflect the safety status of dams,par... The mechanical parameters of materials in a dam body and dam foundation tend to change when dams are reinforced in aging processes.It is important to use an early-warning index to reflect the safety status of dams,particularly of heightened projects in the impoundment period.Herein,a new method for monitoring the safety status of heightened dams is proposed based on the deformation monitoring data of a dam structure,a statistical model,and finite-element numerical simulation.First,a fast optimization inversion method for estimation of dam mechanical parameters was developed,which used the water pressure component extracted from a statistical model,an improved inversion objective function,and a genetic optimization iterative algorithm.Then,a finite element model of a heightened concrete gravity dam was established,and the deformation behavior of the dam with rising water levels in the impoundment period was simulated.Subsequently,mechanical parameters of aged dam parts were calculated using the fast optimization inversion method with simulated deformation and the water pressure deformation component obtained by the statistical model under the same conditions of water pressure change.Finally,a new earlywarning index of dam deformation was constructed by means of the forward-simulated deformation and other components of the statistical model.The early-warning index is useful for forecasting dam deformation under different water levels,especially high water levels. 展开更多
关键词 Concrete gravity dam parameter inverse analysis Structural health monitoring early-warning index Finite element simulation
在线阅读 下载PDF
Carbody Structural Lightweighting Based on Implicit Parameterized Model 被引量:8
11
作者 CHEN Xin MA Fangwu +1 位作者 WANG Dengfeng XIE Chen 《Chinese Journal of Mechanical Engineering》 SCIE EI CAS CSCD 2014年第3期483-487,共5页
Most of recent research on carbody lightweighting has focused on substitute material and new processing technologies rather than structures. However, new materials and processing techniques inevitably lead to higher c... Most of recent research on carbody lightweighting has focused on substitute material and new processing technologies rather than structures. However, new materials and processing techniques inevitably lead to higher costs. Also, material substitution and processing lightweighting have to be realized through body structural profiles and locations. In the huge conventional workload of lightweight optimization, model modifications involve heavy manual work, and it always leads to a large number of iteration calculations. As a new technique in carbody lightweighting, the implicit parameterization is used to optimize the carbody structure to improve the materials utilization rate in this paper. The implicit parameterized structural modeling enables the use of automatic modification and rapid multidisciplinary design optimization (MDO) in carbody structure, which is impossible in the traditional structure finite element method (FEM) without parameterization. The structural SFE parameterized model is built in accordance with the car structural FE model in concept development stage, and it is validated by some structural performance data. The validated SFE structural parameterized model can be used to generate rapidly and automatically FE model and evaluate different design variables group in the integrated MDO loop. The lightweighting result of body-in-white (BIW) after the optimization rounds reveals that the implicit parameterized model makes automatic MDO feasible and can significantly improve the computational efficiency of carbody structural lightweighting. This paper proposes the integrated method of implicit parameterized model and MDO, which has the obvious practical advantage and industrial significance in the carbody structural lightweighting design. 展开更多
关键词 carbody structural lightweighting implicit parameterization MDO BIW
在线阅读 下载PDF
Evolution of coordination degree of eco-economic system and early-warning in the Yangtze River Delta 被引量:26
12
作者 WANG Zhenbo FANG Chuanglin +1 位作者 CHENG Shaowen WANG Jing 《Journal of Geographical Sciences》 SCIE CSCD 2013年第1期147-162,共16页
On the basis of Landsat TM data of the Yangtze River Delta (YRD) Economic Zone in 1991, 2001 and 2008, this article, taking 90 counties in this region as study units, built spatial data transformation models, ecosys... On the basis of Landsat TM data of the Yangtze River Delta (YRD) Economic Zone in 1991, 2001 and 2008, this article, taking 90 counties in this region as study units, built spatial data transformation models, ecosystem service value (ESV) and coordination degree of eco-economic system (CDES) models. With the aid of ArcGIS9.3, mass grid and vector data has been processed for spatial analyses. ESV and CDES indexes have demonstrated the relationship between economic development and eco-environment system and its evolu- tion characteristics in the researched areas. Furthermore, the indexes have also been used for functional zoning and pattern recognition. Some results can be shown as follows. Firstly, since 1991, land use in the YRD has greatly changed: urban land area has increased primar- ily from original paddy land, dry land, grassland, garden plot and other land. Secondly, the ESV model has proved the deterioration trend of the YRD ecological system from 1991 to 2001 and slower degradation trend during 2001-2008. Also, it is illustrated that land-use conversion from water area and paddy field to urban area and dry land could cause great damage to ecosystem stabilization. Thirdly, GDP in the central and southern parts of the YRD is higher than that in the northern part since 1991. GDP growth rate in the central part is higher than that in the northern part during 1991-2001. This growth rate in the central part is also higher than that in the southern and northern parts of the YRD from 2001 to 2008. Fourthly, the YRD could be categorized into 12 types of subregions in terms of CDES index. According to its spatial characteristic of CDES index value in the study area, eco-economic conflict area with low CDES value which is located in the central part is surrounded by eco-coordinated areas with high CDES values. This illustrates a core-periphery spatial structure exists in the YRD. During 1991-2001, the CDES value implied the convergent de- terioration trend of eco-economic system in the study area; while it gradually stepped into coexistence of divergent deterioration and coordination during 2001-2008. Finally, this paper analyzed five subregions in the YRD, including initially degrading zone, initially coordinative zone, continuously degrading zone, coordination-declined.zone and coordination-promoted zone, based on eco-economic coordination and evolution patterns. And these subregions can be recognized and categorized by spatial transformation model. 展开更多
关键词 Yangtze River Delta rapid urbanization region LUCC eco-service value eco-economic coordination early-warning
原文传递
A parameterized geometry design method for inward turning inlet compatible waverider 被引量:5
13
作者 Tian Chao Li Ni +1 位作者 Gong Guanghong Su Zeya 《Chinese Journal of Aeronautics》 SCIE EI CAS CSCD 2013年第5期1135-1146,共12页
Intensive studies have been carried out on generations of waverider geometry and hypersonic inlet geometry. However, integration efforts of waverider and related air-intake system are restricted majorly around the X43... Intensive studies have been carried out on generations of waverider geometry and hypersonic inlet geometry. However, integration efforts of waverider and related air-intake system are restricted majorly around the X43A-like or conical flow field induced configuration, which adopts mainly the two-dimensional air-breathing technology and limits the judicious visions of developing new aerodynamic profiles for hypersonic designers. A novel design approach for integrating the inward turning inlet with the traditional parameterized waverider is proposed. The proposed method is an alternative means to produce a compatible configuration by linking the off-the-shelf results on both traditional waverider techniques and inward turning inlet techniques. A series of geometry generations and optimization solutions is proposed to enhance the lift-to-drag ratio. A quantitative but efficient aerodynamic performance evaluation approach (the hypersonic flow panel method) with lower computational cost is employed to play the role of objective function for opti- mization purpose. The produced geometry compatibility with a computational fluid dynamics (CFD) solver is also verified for detailed flow field investigation. Optimization results and other numerical validations are obtained for the feasibility demonstration of the proposed method. 展开更多
关键词 Hypersonic inlets Hypersonic vehicles Inward turning inlet Optimization parameterIZATION WAVERIDER
原文传递
Parameterized Littlewood-Paley Operators and Their Commutators on Lebesgue Spaces with Variable Exponent 被引量:6
14
作者 Lijuan Wang Shuangping Tao 《Analysis in Theory and Applications》 CSCD 2015年第1期13-24,共12页
In this paper, by applying the technique of the sharp maximal function and the equivalent representation of the norm in the Lebesgue spaces with variable exponent, the boundedness of the parameterized Litflewood-Paley... In this paper, by applying the technique of the sharp maximal function and the equivalent representation of the norm in the Lebesgue spaces with variable exponent, the boundedness of the parameterized Litflewood-Paley operators, including the parameterized Lusin area integrals and the parameterized Littlewood-Paley gλ^*- functions, is established on the Lebesgue spaces with variable exponent. Furthermore, the boundedness of their commutators generated respectively by BMO functions and Lipschitz functions are also obtained. 展开更多
关键词 parameterized Littlewood-Paley operators COMMUTATORS Lebesgue spaces with variable exponent.
在线阅读 下载PDF
Adaptive Iterative Learning Control for Nonlinearly Parameterized Systems with Unknown Time-varying Delay and Unknown Control Direction 被引量:13
15
作者 Dan Li Jun-Min Li Department of Mathematics,Xidian University,Xi an 710071,China 《International Journal of Automation and computing》 EI 2012年第6期578-586,共9页
This paper proposes a new adaptive iterative learning control approach for a class of nonlinearly parameterized systems with unknown time-varying delay and unknown control direction.By employing the parameter separati... This paper proposes a new adaptive iterative learning control approach for a class of nonlinearly parameterized systems with unknown time-varying delay and unknown control direction.By employing the parameter separation technique and signal replacement mechanism,the approach can overcome unknown time-varying parameters and unknown time-varying delay of the nonlinear systems.By incorporating a Nussbaum-type function,the proposed approach can deal with the unknown control direction of the nonlinear systems.Based on a Lyapunov-Krasovskii-like composite energy function,the convergence of tracking error sequence is achieved in the iteration domain.Finally,two simulation examples are provided to illustrate the feasibility of the proposed control method. 展开更多
关键词 Nonlinearly time-varying parameterized systems unknown time-varying delay unknown control direction composite energy function adaptive iterative learning control.
原文传递
Introduction of parameterized sea ice drag coefficients into ice free-drift modeling 被引量:2
16
作者 LU Peng LI Zhijun HAN Hongwei 《Acta Oceanologica Sinica》 SCIE CAS CSCD 2016年第1期53-59,共7页
Many interesting characteristics of sea ice drift depend on the atmospheric drag coefficient (Ca) and oceanic drag coefficient (Cw). Parameterizations of drag coefficients rather than constant values provide us a ... Many interesting characteristics of sea ice drift depend on the atmospheric drag coefficient (Ca) and oceanic drag coefficient (Cw). Parameterizations of drag coefficients rather than constant values provide us a way to look insight into the dependence of these characteristics on sea ice conditions. In the present study, the parameterized ice drag coefficients are included into a free-drift sea ice dynamic model, and the wind factor a and the deflection angle θ between sea ice drift and wind velocity as well as the ratio of Ca to Cw are studied to investigate their dependence on the impact factors such as local drag coefficients, floe and ridge geometry. The results reveal that in an idealized steady ocean, Ca/Cw increases obviously with the increasing ice concentration for small ice floes in the marginal ice zone, while it remains at a steady level (0.2-0.25) for large floes in the central ice zone. The wind factor a increases rapidly at first and approaches a steady level of 0.018 when A is greater than 20%. And the deflection angle ~ drops rapidly from an initial value of approximate 80° and decreases slowly as A is greater than 20% without a steady level like a. The values of these parameters agree well with the previously reported observations in Arctic. The ridging intensity is an important parameter to determine the dominant contribution of the ratio of skin friction drag coefficient (Cs'/Cs) and the ratio of ridge form drag coefficient (Cr'/Cr) to the value of Ca/Cw, a, and 8, because of the dominance of ridge form drag for large ridging intensity and skin friction for small ridging intensity among the total drag forces. Parameterization of sea ice drag coefficients has the potential to be embedded into ice dynamic models to better account for the variability of sea ice in the transient Arctic Ocean. 展开更多
关键词 sea ice drag coefficient parameterIZATION free drift MODELING
在线阅读 下载PDF
China agricultural outlook for 2015–2024 based on China Agricultural Monitoring and Early-warning System(CAMES) 被引量:14
17
作者 XU Shi-wei LI Gan-qiong LI Zhe-min 《Journal of Integrative Agriculture》 SCIE CAS CSCD 2015年第9期1889-1902,共14页
The primary goal of Chinese agricultural development is to guarantee national food security and supply of major agricultural products. Hence, the scientiifc work on agricultural monitoring and early warning as wel as ... The primary goal of Chinese agricultural development is to guarantee national food security and supply of major agricultural products. Hence, the scientiifc work on agricultural monitoring and early warning as wel as agricultural outlook must be strengthened. In this study, we develop the China Agricultural Monitoring and Early-warning System (CAMES) on the basis of a comparative study of domestic and international agricultural outlook models. The system is a dynamic and multi-market partial equilibrium model that integrates biological mechanisms with economic mechanisms. This system, which includes 11 categories of 953 kinds of agricultural products, could dynamical y project agricultural market supply and demand, assess food security, and conduct scenario analysis at different spatial levels, time scale levels, and macro-micro levels. Based on the CAMES, the production, consumption, and trade of the major agricultural products in China over the next decade are projected. The fol owing conclusions are drawn:i) The production of major agricultural products wil continue to grow steadily, mainly because of the increase in yield. i ) The growth of agricultural consumption wil be slightly higher than that of agricultural production. Meanwhile, a high self-sufifciency rate is expected for cereals such as rice, wheat, and maize, with the rate being stable at around 97%. i i) Agricultural trade wil continue to thrive. The growth of soybean and milk im-ports wil slow down, but the growth of traditional agricultural exports such as vegetables and fruits is expected to continue. 展开更多
关键词 agricultural outlook PROJECTION China Agricultural Monitoring and early-warning System(CAMES) agriculture of China
在线阅读 下载PDF
Characteristics Analysis and the Early-warning Service System of Heavy Fog in Chizhou City 被引量:5
18
作者 齐建华 杨春雷 +2 位作者 阮玲 张仕清 房厚林 《Meteorological and Environmental Research》 CAS 2010年第5期71-75,79,共6页
By analyzing the heavy fog data in Chizhou City in recent 50 years(1959-2007),the general rules of meteorological elements variations were found when the heavy fog happened.The meteorological elements included the tem... By analyzing the heavy fog data in Chizhou City in recent 50 years(1959-2007),the general rules of meteorological elements variations were found when the heavy fog happened.The meteorological elements included the temperature,humidity,wind direction,wind speed,air pressure and so on.The conceptual models of high-altitude and ground situation were established when the heavy fog happened in Chizhou City.Based on considering sufficiently the special geographical environment in Chizhou City,we found the key factors which affected the local heavy fog via the relative analyses.By using the statistical forecast methods which included the second-level judgment method and regression method of event probability and so on,the forecast mode equation of heavy fog was established.Moreover,the objective forecast system of heavy fog in Chizhou City was also manufactured.It provided the basis and platform which could be referred for the heavy fog forecast,service and the release of early-warning signal. 展开更多
关键词 Heavy fog Climate characteristic Forecast method early-warning system China
在线阅读 下载PDF
Data Processing Model of Coalmine Gas Early-Warning System 被引量:8
19
作者 QIAN Jian-sheng YIN Hong-sheng +2 位作者 LIU Xiu-rong HUA Gang XU Yong-gang 《Journal of China University of Mining and Technology》 EI 2007年第1期20-24,共5页
The data processing mode is vital to the performance of an entire coalmine gas early-warning system, especially in real-time performance. Our objective was to present the structural features of coalmine gas data, so t... The data processing mode is vital to the performance of an entire coalmine gas early-warning system, especially in real-time performance. Our objective was to present the structural features of coalmine gas data, so that the data could be processed at different priority levels in C language. Two different data processing models, one with priority and the other without priority, were built based on queuing theory. Their theoretical formulas were determined via a M/M/I model in order to calculate average occupation time of each measuring point in an early-warning program. We validated the model with the gas early-warning system of the Huaibei Coalmine Group Corp. The results indicate that the average occupation time for gas data processing by using the queuing system model with priority is nearly 1/30 of that of the model without priority. 展开更多
关键词 gas early-warning data processing queuing theory priority model high efficiency
在线阅读 下载PDF
Information fusion diagnosis and early-warning method for monitoring the long-term service safety of high dams 被引量:3
20
作者 Xing LIU Zhong-ru WU +2 位作者 Yang YANG Jiang HU Bo XU 《Journal of Zhejiang University-Science A(Applied Physics & Engineering)》 SCIE EI CAS CSCD 2012年第9期687-699,共13页
Analyzing the service behavior of high dams and establishing early-warning systems for them have become increasingly important in ensuring their long-term service.Current analysis methods used to obtain safety monitor... Analyzing the service behavior of high dams and establishing early-warning systems for them have become increasingly important in ensuring their long-term service.Current analysis methods used to obtain safety monitoring data are suited only to single survey point data.Unreliable or even paradoxical results are inevitably obtained when processing large amounts of monitoring data,thereby causing difficulty in acquiring precise conclusions.Therefore,we have developed a new method based on multi-source information fusion for conducting a comprehensive analysis of prototype monitoring data of high dams.In addition,we propose the use of decision information entropy analysis for building a diagnosis and early-warning system for the long-term service of high dams.Data metrics reduction is achieved using information fusion at the data level.A Bayesian information fusion is then conducted at the decision level to obtain a comprehensive diagnosis.Early-warning outcomes can be released after sorting analysis results from multi-positions in the dam according to importance.A case study indicates that the new method can effectively handle large amounts of monitoring data from numerous survey points.It can likewise obtain precise real-time results and export comprehensive early-warning outcomes from multi-positions of high dams. 展开更多
关键词 Dam monitoring DIAGNOSIS early-warning Multi-source information fusion Information entropy
原文传递
上一页 1 2 250 下一页 到第
使用帮助 返回顶部