期刊文献+
共找到16,973篇文章
< 1 2 250 >
每页显示 20 50 100
Project Systems Engineering for Developing Space Robots
1
作者 Li Gengtian, Li ZhibinBeijing Institute of Control Engineering, P.O.Box 2729, Beijing 100080, ChinaLü YingxiangBeijing Institute of Electromechanic System Engineering.P.O.Box 142-206, Beijing 100854, China 《Journal of Systems Engineering and Electronics》 SCIE EI CSCD 1991年第1期97-106,共10页
Space robots possess unique distinguishing features unlike general robots on earth, due to the particular environments in space. The developing of various practical space robots promoting the improvement of space scie... Space robots possess unique distinguishing features unlike general robots on earth, due to the particular environments in space. The developing of various practical space robots promoting the improvement of space science and technology is a complex man-machine-environment engineering problem. This paper analyses from the systems engineering viewpoint the space robot system in the scope of the architecture of robotics discipline, space environment characteristics, man-machine-environment system of space robots, the general methodology of project systems engineering and the process of space robot systems engineering. 展开更多
关键词 Space robots systems engineering project systems engineering.
在线阅读 下载PDF
Green Project System Design of Machine Process Factory
2
作者 CHEN Jian-fei, LI Jian-hua, CUI Jiang-hong, ZHANG Su-x iang, LI Chun-guang, NIU Yong-sheng (Department of Mechanical Engineering, Zhongyuan Institute of Technolog y, Zhengzhou 450007, China) 《厦门大学学报(自然科学版)》 CAS CSCD 北大核心 2002年第S1期77-78,共2页
As the specialty of the product and the dim conscio us ness of environmental protection, the status of dirty, chaos and difference is l ong-term existed in the machine process factory. It seriously affects workers’ w... As the specialty of the product and the dim conscio us ness of environmental protection, the status of dirty, chaos and difference is l ong-term existed in the machine process factory. It seriously affects workers’ work and living environment, and restricts the total level of the environment p rotection in our country. The project is the fatal scientific research task of H enan province in 2001. As the members’ endeavor of task group, we have finished the total plan of green project system and some other key equipment to the mach ine process factory, such as the design of conveyer of chip, hydraulic former of chip, rough conveyer and dirt collector. And the green project system is made i nto model that the manufacturer can select. This item is a fire-new work. We ho pe that the expert of machine, environment protection and government official ca n put forward some advices by lodging this article. We contribute for our countr y’ environment protection and make it attain a new level. 展开更多
关键词 environment protection green project MACHINING CHIP TRANSPORTATION
在线阅读 下载PDF
Projective synchronization control and simulation of drive system and response network
3
作者 LI De-kui 《兰州大学学报(自然科学版)》 北大核心 2025年第2期208-214,共7页
Projective synchronization problems of a drive system and a particular response network were investigated,where the drive system is an arbitrary system with n+1 dimensions;it may be a linear or nonlinear system,and ev... Projective synchronization problems of a drive system and a particular response network were investigated,where the drive system is an arbitrary system with n+1 dimensions;it may be a linear or nonlinear system,and even a chaotic or hyperchaotic system,the response network is complex system coupled by N nodes,and every node is showed by the approximately linear part of the drive system.Only controlling any one node of the response network by designed controller can achieve the projective synchronization.Some numerical examples were employed to verify the effectiveness and correctness of the designed controller. 展开更多
关键词 pinning control projective synchronization drive system response network
原文传递
M-Estimation-Based Minimum Error Entropy with Affine Projection Algorithm for Outlier Suppression in Spaceborne SAR System
4
作者 WANG Weixin CHANG Xuelian OU Shifeng 《Transactions of Nanjing University of Aeronautics and Astronautics》 2025年第5期615-628,共14页
Conventional adaptive filtering algorithms often exhibit performance degradation when processing multipath interference in raw echoes of spaceborne synthetic aperture radar(SAR)systems due to anomalous outliers,manife... Conventional adaptive filtering algorithms often exhibit performance degradation when processing multipath interference in raw echoes of spaceborne synthetic aperture radar(SAR)systems due to anomalous outliers,manifesting as insufficient convergence and low estimation accuracy.To address this issue,this study proposes a novel robust adaptive filtering algorithm,namely the M-estimation-based minimum error entropy with affine projection(APMMEE)algorithm.This algorithm inherits the joint multi-data-block update mechanism of the affine projection algorithm,enabling rapid adaptation to the dynamic characteristics of raw echoes and achieving fast convergence.Meanwhile,it incorporates the M-estimation-based minimum error entropy(MMEE)criterion,which weights error samples in raw echoes through M-estimation functions,effectively suppressing outlier interference during the algorithm update.Both the system identification simulations and practical multipath interference suppression experiments using raw echoes demonstrate that the proposed APMMEE algorithm exhibits superior filtering performance. 展开更多
关键词 radar signal adaptive filtering minimum error entropy M-ESTIMATION affine projection
在线阅读 下载PDF
Impact of Land Use Change on Ecosystem Services Values in Danjiangkou Reservoir Area,China in the Context of National Water Network Project Construction
5
作者 LIU Linghua ZHENG Liang +3 位作者 WANG Ying LIU Chongchong ZHANG Bowen BI Yuzhe 《Chinese Geographical Science》 2025年第1期111-130,共20页
Investigating the ecological impact of land use change in the context of the construction of national water network project is crucial,as it is imperative for achieving the sustainable development goals of the nationa... Investigating the ecological impact of land use change in the context of the construction of national water network project is crucial,as it is imperative for achieving the sustainable development goals of the national water network and guaranteeing regional ecological stability.Using the Danjiangkou Reservoir Area(DRA),China as the study area,this paper first examined the spatiotemporal dynamics of natural landscape patterns and ecosystem service values(ESV)in the DRA from 2000 to 2018 and then investigated the spatial clustering characteristics of the ESV using spatial statistical analysis tools.Finally,the patch-generating land use simulation(PLUS)model was used to simulate the natural landscape and future changes in the ESV of the DRA from 2018 to 2028 under four different development scenarios:business as usual(BAU),economic development(ED),ecological protection(EP),and shoreline protection(SP).The results show that:during 2000-2018,the construction of water facilities had a significant impact on regional land use/land cover(LULC)change,with a 24830 ha increase in watershed area.ESV exhibited an increasing trend,with a significant and growing spatial clustering effect.The transformation of farmland to water bodies led to accelerated ESV growth,while the transformation of forest land to farmland led to a decrease in the ESV.Normalized difference vegetation index(NDVI)had the strongest effect on the ESV.ESV exhibited a continuous increase from 2018 to 2028 under all the simulation scenarios.The EP scenario had the greatest increase in ESV,while the ED scenario had the smallest increase.The findings suggest that projected land use patterns under different scenarios have varied impacts on ecosystem services(ESs)and that the management and planning of the DRA should balance social,economic,ecological,and security benefits.nomic,ecological,and security benefits. 展开更多
关键词 ecosystem services value(ESV) national water network project of China South-to-North Water Diversion project(SNWDP)of China multi-scenario simulation Danjiangkou Reservoir Area China
在线阅读 下载PDF
Hotspots of disagreement across global urban land projections until 2100
6
作者 Jasper van Vliet Hang Yang +9 位作者 Nathalie Benz Changxiu Cheng Jonathan Doelman Jing Gao Qingxu Huang Eric Koomen Xuecao Li Lu Niu Elizabeth A.Schrammeijer Yuyu Zhou 《Geography and Sustainability》 2026年第1期155-165,共11页
Projections of future urban land change are essential for a range of sustainability assessments,including those related to biodiversity loss,carbon emissions,and agricultural land conversion.However,to what extent and... Projections of future urban land change are essential for a range of sustainability assessments,including those related to biodiversity loss,carbon emissions,and agricultural land conversion.However,to what extent and where current projections agree or disagree remains unknown.Here,we systematically compare existing global projections that are consistent with the Shared Socioeconomic Pathways.We find that the total global urban land area is expected to increase by 112%between 2020 and 2100(averaged across all projections),with a coefficient of variation of 0.81.This variation is mostly caused by the selection of the underlying drivers that are included in the different models.Regionally,the highest average growth rates are found in sub-Saharan Africa(+679%to+730%),while this region also has the highest variation across projections(coefficient of variation ranging from 2.02 to 2.18).When ranking scenarios within a study from the highest to the lowest projected increase in urban land,rankings are relatively similar for regions in the Global North,but not for regions in the Global South.The large disagreement across projections can lead to high uncertainties in assessments of future urban land change impacts,which can undermine the effectiveness of long-term planning,policymaking,and resource management decisions. 展开更多
关键词 GLOBAL Urban BUILT-UP projections SSPs Model comparison
在线阅读 下载PDF
Predictable and Unpredictable Modes of Northern Hemisphere Atmospheric Circulation in CMIP6:Evaluation and Projections
7
作者 Kairan YING Dabang JIANG Linhao ZHONG 《Advances in Atmospheric Sciences》 2026年第1期135-156,共22页
Climate models are essential for understanding past,present,and future changes in atmospheric circulation,with circulation modes providing key sources of seasonal predictability and prediction uncertainties for both g... Climate models are essential for understanding past,present,and future changes in atmospheric circulation,with circulation modes providing key sources of seasonal predictability and prediction uncertainties for both global and regional climates.This study assesses the performance of models participating in phase 6 of the Coupled Model Intercomparison Project in simulating interannual variability modes of Northern Hemisphere 500-hPa geopotential height during winter and summer,distinguishing predictable(potentially predictable on seasonal or longer timescales)and unpredictable(intraseasonal and essentially unpredictable at long range)components,using reanalysis data and a variance decomposition method.Although most models effectively capture unpredictable modes in reanalysis,their ability to reproduce dominant predictable modes-specifically the Pacific-North American pattern,Arctic Oscillation,and Western Pacific Oscillation in winter,and the East Atlantic and North Atlantic Oscillations in summer-varies notably.An optimal ensemble is identified to distinguish(a)predictable-external modes,dominated by external forcing,and(b)predictable-internal modes,associated with slow internal variability,during the historical period(1950-2014)and the SSP5-8.5 scenario(2036-2100).Under increased radiative forcing,the leading winter/summer predictable-external mode exhibits a more uniform spatial distribution,remarkably larger trend and annual variance,and enhanced height-sea surface temperature(SST)covariance under SSP5-8.5 compared to historical conditions.The dominant winter/summer predictable-internal modes also exhibit increased variance and height-SST covariance under SSP5-8.5,along with localized changes in spatial configuration.Minimal changes are observed in spatial distribution or variance for dominant winter/summer unpredictable modes under SSP5-8.5.This study,from a predictive perspective,deepens our understanding of model uncertainties and projected changes in circulations. 展开更多
关键词 interannual mode of atmospheric circulation CMIP6 predictable unpredictable EVALUATION projectION
在线阅读 下载PDF
A Nexus for East Africa--China-supported projects help East Africans to boost energy, water and food security
8
作者 RICHARD WETAYA 《ChinAfrica》 2026年第1期44-45,共2页
Andrew Wangota,a 48-year-old Ugandan farmer,has been using agrivoltaics technology,a solar technology that uses agricultural land for both food production and solar power generation,on his farm in Bunashimolo Parish,B... Andrew Wangota,a 48-year-old Ugandan farmer,has been using agrivoltaics technology,a solar technology that uses agricultural land for both food production and solar power generation,on his farm in Bunashimolo Parish,Bukyiende Subcounty in Uganda where he has been cultivating plantain,coffee and Irish potatoes for the past 16 years. 展开更多
关键词 water security solar technology NEXUS irish potatoes East Africa energy security China supported projects agrivoltaics technologya
原文传递
初中英语新教材Project板块教学实践初探
9
作者 刘小菊 《视周刊》 2026年第5期9-10,共2页
随着教育改革的持续深入,初中英语教学需突破传统的知识灌输模式,构建能力本位、素养导向的教育模式,驱动学生的深度学习和主动思考。人教版初中英语新教材中的Project板块,是单元知识的综合运用平台,强调学生通过合作创作、自主探究与... 随着教育改革的持续深入,初中英语教学需突破传统的知识灌输模式,构建能力本位、素养导向的教育模式,驱动学生的深度学习和主动思考。人教版初中英语新教材中的Project板块,是单元知识的综合运用平台,强调学生通过合作创作、自主探究与成果展示,实现语言技能、思维品质、学习能力的全面提升。 展开更多
关键词 初中英语 project板块 新教材 能力本位
原文传递
Individual Software Expertise Formalization and Assessment from Project Management Tool Databases
10
作者 Traian-Radu Plosca Alexandru-Mihai Pescaru +1 位作者 Bianca-Valeria Rus Daniel-Ioan Curiac 《Computers, Materials & Continua》 2026年第1期389-411,共23页
Objective expertise evaluation of individuals,as a prerequisite stage for team formation,has been a long-term desideratum in large software development companies.With the rapid advancements in machine learning methods... Objective expertise evaluation of individuals,as a prerequisite stage for team formation,has been a long-term desideratum in large software development companies.With the rapid advancements in machine learning methods,based on reliable existing data stored in project management tools’datasets,automating this evaluation process becomes a natural step forward.In this context,our approach focuses on quantifying software developer expertise by using metadata from the task-tracking systems.For this,we mathematically formalize two categories of expertise:technology-specific expertise,which denotes the skills required for a particular technology,and general expertise,which encapsulates overall knowledge in the software industry.Afterward,we automatically classify the zones of expertise associated with each task a developer has worked on using Bidirectional Encoder Representations from Transformers(BERT)-like transformers to handle the unique characteristics of project tool datasets effectively.Finally,our method evaluates the proficiency of each software specialist across already completed projects from both technology-specific and general perspectives.The method was experimentally validated,yielding promising results. 展开更多
关键词 Expertise formalization transformer-based models natural language processing augmented data project management tool skill classification
在线阅读 下载PDF
The Observed and Projected Changes of Global Monsoons:Current Status and Future Perspectives
11
作者 Tianjun ZHOU Xiaolong CHEN +11 位作者 Wenxia ZHANG Bo WU Ziming CHEN Jie JIANG Xin HUANG Shuai HU Meng ZUO Wenmin MAN Lixia ZHANG Zhun GUO Pengfei LIN Lu WANG 《Advances in Atmospheric Sciences》 2026年第1期30-58,共29页
The global monsoon system,encompassing the Asian-Australian,African,and American monsoons,sustains two-thirds of the world’s population by regulating water resources and agriculture.Monsoon anomalies pose severe risk... The global monsoon system,encompassing the Asian-Australian,African,and American monsoons,sustains two-thirds of the world’s population by regulating water resources and agriculture.Monsoon anomalies pose severe risks,including floods and droughts.Recent research associated with the implementation of the Global Monsoons Model Intercomparison Project under the umbrella of CMIP6 has advanced our understanding of its historical variability and driving mechanisms.Observational data reveal a 20th-century shift:increased rainfall pre-1950s,followed by aridification and partial recovery post-1980s,driven by both internal variability(e.g.,Atlantic Multidecadal Oscillation)and external forcings(greenhouse gases,aerosols),while ENSO drives interannual variability through ocean-atmosphere interactions.Future projections under greenhouse forcing suggest long-term monsoon intensification,though regional disparities and model uncertainties persist.Models indicate robust trends but struggle to quantify extremes,where thermodynamic effects(warming-induced moisture rise)uniformly boost heavy rainfall,while dynamical shifts(circulation changes)create spatial heterogeneity.Volcanic eruptions and proposed solar radiation modification(SRM)further complicate predictions:tropical eruptions suppress monsoons,whereas high-latitude events alter cross-equatorial flows,highlighting unresolved feedbacks.The emergent constraint approach is booming in terms of correcting future projections and reducing uncertainty with respect to the global monsoons.Critical challenges remain.Model biases and sparse 20th-century observational data hinder accurate attribution.The interplay between natural variability and anthropogenic forcings,along with nonlinear extreme precipitation risks under warming,demands deeper mechanistic insights.Additionally,SRM’s regional impacts and hemispheric monsoon interactions require systematic evaluation.Addressing these gaps necessitates enhanced observational networks,refined climate models,and interdisciplinary efforts to disentangle multiscale drivers,ultimately improving resilience strategies for monsoon-dependent regions. 展开更多
关键词 global monsoons interannual variability decadal variability detection and attribution climate extreme events projection uncertainty
在线阅读 下载PDF
基于项目化学习的小学英语Project板块教学研究——以“Project:Make a poster of a happy family”为例
12
作者 龚秋萍 《教育界》 2026年第4期134-136,共3页
当下,小学英语板块教学存在活动形式单一化、探究活动浅表化等问题,综合育人价值未能完全发挥。为改变这一现状,文章以人教版英语(PEP)四年级上册Unit 1“Helping at home”的“Project:Make a poster of a happy family”为例,以项目... 当下,小学英语板块教学存在活动形式单一化、探究活动浅表化等问题,综合育人价值未能完全发挥。为改变这一现状,文章以人教版英语(PEP)四年级上册Unit 1“Helping at home”的“Project:Make a poster of a happy family”为例,以项目化学习为支架,围绕项目设计、过程实施、评价反馈、成果展示等维度探究有效教学策略,旨在优化Project板块的教学模式,引导学生在项目化学习中提升语言运用能力和综合实践能力。 展开更多
关键词 项目化学习 小学英语 project板块
在线阅读 下载PDF
基于项目化学习的人教版初中英语教材Project 板块教学探究——以 Unit 4 My Favourite Subject为例
13
作者 卢华英 丁旦群 《英语教师》 2026年第3期97-100,119,共5页
目前初中英语教学中项目化学习面临困境,而人教版初中英语教材中的Project板块为开展英语综合实践活动提供了载体,为提升学生用英语解决生活中实际问题的能力提供了平台。在实践中,教师可以以项目化学习的方式开展Project板块的教学。... 目前初中英语教学中项目化学习面临困境,而人教版初中英语教材中的Project板块为开展英语综合实践活动提供了载体,为提升学生用英语解决生活中实际问题的能力提供了平台。在实践中,教师可以以项目化学习的方式开展Project板块的教学。具体可分为四个环节:规划准备环节,以任务为驱动,引导学生进行内容选择和任务分工;实施制作环节,提供内容和工具支架,帮助学生打磨作品细节,完成成果制作;分享评价环节,师生对项目汇报及项目成果进行多元评价;反思复盘环节,引导学生复盘学习过程,进行自我反思。实践证明,项目化学习和Project板块的教学相互促进,能够促进学生综合能力的发展。 展开更多
关键词 人教版初中英语教材 项目化学习 project板块
在线阅读 下载PDF
Study on Safeguard System of Eco-tourism Compensation of Hukou Section during Ecological Water-control Project of Poyang Lake 被引量:1
14
作者 龚双双 沈中印 +1 位作者 孙冬英 杨云仙 《Journal of Landscape Research》 2010年第12期58-62,72,共6页
Through analysis on the background to develop eco-tourism and necessity for ecological compensation,based on specific condition of Hukou County,in line with the situation to develop eco-tourism during ecological water... Through analysis on the background to develop eco-tourism and necessity for ecological compensation,based on specific condition of Hukou County,in line with the situation to develop eco-tourism during ecological water control project of Poyang Lake,residents' interest protection system and ecological benefit safeguard system for eco-tourism compensation were put forward. 展开更多
关键词 Poyang Lake ECOLOGICAL WATER control project ECO-TOURISM COMPENSATION Hukou SECTION
在线阅读 下载PDF
The functional roles of feedback projections in the visual system
15
作者 寿天德 《Neuroscience Bulletin》 SCIE CAS CSCD 2010年第5期401-410,共10页
Neurons in the nervous system make connections with ascending feedforward projections and descending feedback projections,as well as projections from neural structures at the identical hierarchical level.These neurons... Neurons in the nervous system make connections with ascending feedforward projections and descending feedback projections,as well as projections from neural structures at the identical hierarchical level.These neurons form extremely complicated neural networks and pathways.Compared with the role of the feedforward projection,much less is known concerning the functional roles of the feedback projection.Visual cortex is a good model for studying functional roles of cortical feedback projections which involve many high functions,such as attention,searching and cognition.The present review mainly focused on the functional roles of feedback projections in the visual system. 展开更多
关键词 feedback projection feedforward projection visual system visual attention oblique effect
原文传递
The Project System:A New Form of State Governance
16
作者 渠敬东 《Social Sciences in China》 2012年第4期28-47,共20页
As the incremental component of the new dual track system, the project system aims to use special transfer payments from state finances and other strategies to break the shackles of the existing bureaucratic order, as... As the incremental component of the new dual track system, the project system aims to use special transfer payments from state finances and other strategies to break the shackles of the existing bureaucratic order, as represented by the work unit system. This approach seeks to curb the polarization arising from marketization and increase investment in people's livelihood and public services. The new project-centered system of governance has encouraged the formation of hierarchical central-local governance mechanisms, leading to a number of unforeseen outcomes for grassroots society. Collective debt at the grassroots level, departmental interests and the systemic risk brought about by the project system will have important implications for the sustainable development of society. 展开更多
关键词 the project system new dual track system project economy project power project chain
原文传递
Generalized projective synchronization of chaotic systems via adaptive learning control 被引量:19
17
作者 孙云平 李俊民 +1 位作者 王江安 王辉林 《Chinese Physics B》 SCIE EI CAS CSCD 2010年第2期119-126,共8页
In this paper, a learning control approach is applied to the generalized projective synchronisation (GPS) of different chaotic systems with unknown periodically time-varying parameters. Using the Lyapunov--Krasovski... In this paper, a learning control approach is applied to the generalized projective synchronisation (GPS) of different chaotic systems with unknown periodically time-varying parameters. Using the Lyapunov--Krasovskii functional stability theory, a differential-difference mixed parametric learning law and an adaptive learning control law are constructed to make the states of two different chaotic systems asymptotically synchronised. The scheme is successfully applied to the generalized projective synchronisation between the Lorenz system and Chen system. Moreover, numerical simulations results are used to verify the effectiveness of the proposed scheme. 展开更多
关键词 generalized projective synchronisation chaotic systems adaptive learning control Lyapunov--Krasovskii functional
原文传递
Application of system dynamics for assessment of sustainable performance of construction projects 被引量:10
18
作者 SHENL.Y. 吴宇哲 +1 位作者 CHANE.H.W. HAOJ.L. 《Journal of Zhejiang University-Science A(Applied Physics & Engineering)》 SCIE EI CAS CSCD 2005年第4期339-349,共11页
Sustainable performance is expected to become a major factor when examining the feasibility of a construction project in terms of its life cycle performance. The study on which this paper is based developed a simulati... Sustainable performance is expected to become a major factor when examining the feasibility of a construction project in terms of its life cycle performance. The study on which this paper is based developed a simulation model, using system dy- namics methodology, to assess the sustainable performance of projects. Three major factors are used to examine project sus- tainable performance (PSP): the sustainability of economic development (E), the sustainability of social development (S), and the sustainability of environmental development (En). Sustainable development ability (SDA) was used as a prototype to evaluate the degree of sustainable performance. The simulation software ‘ithink’ was used to help with the application of the model to a real life case. This paper explains and demonstrates the procedures used to develop the model and finally offers an approach for assessing the feasibility of a construction project in terms of its sustainable performance. 展开更多
关键词 Construction project project life cycle project sustainable performance (PSP) Sustainable development ability(SDA) system dynamics Simulation
在线阅读 下载PDF
Generalized projective synchronization of a class of chaotic (hyperchaotic) systems with uncertain parameters 被引量:8
19
作者 贾贞 陆君安 +1 位作者 邓光明 张群娇 《Chinese Physics B》 SCIE EI CAS CSCD 2007年第5期1246-1251,共6页
In this paper is investigated the generalized projective synchronization of a class of chaotic (or hyperchaotic) systems, in which certain parameters can be separated from uncertain parameters. Based on the adaptive... In this paper is investigated the generalized projective synchronization of a class of chaotic (or hyperchaotic) systems, in which certain parameters can be separated from uncertain parameters. Based on the adaptive technique, the globally generalized projective synchronization of two identical chaotic (hyperchaotic) systems is achieved by designing a novel nonlinear controller. Furthermore, the parameter identification is realized simultaneously. A sufficient condition for the globally projective synchronization is obtained. Finally, by taking the hyperchaotic L system as example, some numerical simulations are provided to demonstrate the effectiveness and feasibility of the proposed technique. 展开更多
关键词 Chaotic system hyperchaotic system generalized projective synchronization parameter identification
原文传递
上一页 1 2 250 下一页 到第
使用帮助 返回顶部