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Project Systems Engineering for Developing Space Robots
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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.
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Green Project System Design of Machine Process Factory
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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
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Cascading multi-segment rupture process of the 2023 Turkish earthquake doublet on a complex fault system revealed by teleseismic P wave back projection method
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作者 Bonan Cao Zengxi Ge 《Earthquake Science》 2024年第2期158-173,共16页
In this study,the vertical components of broadband teleseismic P wave data recorded by China Earthquake Network are used to image the rupture processes of the February 6th,2023 Turkish earthquake doublet via back proj... In this study,the vertical components of broadband teleseismic P wave data recorded by China Earthquake Network are used to image the rupture processes of the February 6th,2023 Turkish earthquake doublet via back projection analysis.Data in two frequency bands(0.5-2 Hz and 1-3 Hz)are used in the imaging processes.The results show that the rupture of the first event extends about 200 km to the northeast and about 150 km to the southwest,lasting~90 s in total.The southwestern rupture is triggered by the northeastern rupture,demonstrating a sequential bidirectional unilateral rupture pattern.The rupture of the second event extends approximately 80 km in both northeast and west directions,lasting~35 s in total and demonstrates a typical bilateral rupture feature.The cascading ruptures on both sides also reflect the occurrence of selective rupture behaviors on bifurcated faults.In addition,we observe super-shear ruptures on certain fault sections with relatively straight fault structures and sparse aftershocks. 展开更多
关键词 2023 Turkish earthquake doublet back projection method cascading segmented rupture process coseismic triggering super-shear ruptures
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Diagnosis of indirectly driven double shell targets with point-projection hard x-ray radiography
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作者 Chao Tian Minghai Yu +17 位作者 Lianqiang Shan Fengjuan Wu Bi Bi Qiangqiang Zhang Yuchi Wu Tiankui Zhang Feng Zhang Dongxiao Liu Weiwu Wang Zongqiang Yuan Siqian Yang Lei Yang Zhigang Deng Jian Teng Weimin Zhou Zongqing Zhao Yuqiu Gu Baohan Zhang 《Matter and Radiation at Extremes》 SCIE EI CSCD 2024年第2期50-62,共13页
We present an application of short-pulse laser-generated hard x rays for the diagnosis of indirectly driven double shell targets. Coneinserted double shell targets were imploded through an indirect drive approach on t... We present an application of short-pulse laser-generated hard x rays for the diagnosis of indirectly driven double shell targets. Coneinserted double shell targets were imploded through an indirect drive approach on the upgraded SG-II laser facility. Then, based on thepoint-projection hard x-ray radiography technique, time-resolved radiography of the double shell targets, including that of their near-peakcompression, were obtained. The backlighter source was created by the interactions of a high-intensity short pulsed laser with a metalmicrowire target. Images of the target near peak compression were obtained with an Au microwire. In addition, radiation hydrodynamicsimulations were performed, and the target evolution obtained agrees well with the experimental results. Using the radiographic images, arealdensities of the targets were evaluated. 展开更多
关键词 double projectION POINT
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Transcriptional regulation in the development and dysfunction of neocortical projection neurons
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作者 Ningxin Wang Rong Wan Ke Tang 《Neural Regeneration Research》 SCIE CAS CSCD 2024年第2期246-254,共9页
Glutamatergic projection neurons generate sophisticated excitatory circuits to integrate and transmit information among different cortical areas,and between the neocortex and other regions of the brain and spinal cord... Glutamatergic projection neurons generate sophisticated excitatory circuits to integrate and transmit information among different cortical areas,and between the neocortex and other regions of the brain and spinal cord.Appropriate development of cortical projection neurons is regulated by certain essential events such as neural fate determination,proliferation,specification,differentiation,migration,survival,axonogenesis,and synaptogenesis.These processes are precisely regulated in a tempo-spatial manner by intrinsic factors,extrinsic signals,and neural activities.The generation of correct subtypes and precise connections of projection neurons is imperative not only to support the basic cortical functions(such as sensory information integration,motor coordination,and cognition)but also to prevent the onset and progression of neurodevelopmental disorders(such as intellectual disability,autism spectrum disorders,anxiety,and depression).This review mainly focuses on the recent progress of transcriptional regulations on the development and diversity of neocortical projection neurons and the clinical relevance of the failure of transcriptional modulations. 展开更多
关键词 autism spectrum disorders COGNITION differentiation excitatory circuits intellectual disability NEOCORTEX neurodevelopmental disorders projection neuron specification transcriptional regulation
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How do lateral septum projections to the ventral CA1 influence sociability?
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作者 Dan Wang Di Zhao +12 位作者 Wentao Wang Fengai Hu Minghu Cui Jing Liu Fantao Meng Cuilan Liu Changyun Qiu Dunjiang Liu Zhicheng Xu Yameng Wang Yu Zhang Wei Li Chen Li 《Neural Regeneration Research》 SCIE CAS CSCD 2024年第8期1789-1801,共13页
Social dysfunction is a risk factor for several neuropsychiatric illnesses.Previous studies have shown that the lateral septum(LS)-related pathway plays a critical role in mediating social behaviors.Howeve r,the role ... Social dysfunction is a risk factor for several neuropsychiatric illnesses.Previous studies have shown that the lateral septum(LS)-related pathway plays a critical role in mediating social behaviors.Howeve r,the role of the connections between the LS and its downstream brain regions in social behavio rs remains unclea r.In this study,we conducted a three-chamber test using electrophysiological and chemogenetic approaches in mice to determine how LS projections to ventral CA1(vCA1)influence sociability.Our res ults showed that gamma-aminobutyric acid(GABA)-e rgic neuro ns were activated following social experience,and that social behavio rs were enhanced by chemogenetic modulation of these neurons.Moreover,LS GABAergic neurons extended their functional neural connections via vCA1 glutamatergic pyramidal neurons,and regulating LSGABA→vCA1Gluneural projections affected social behaviors,which were impeded by suppressing LSprojecting vCA1 neuronal activity or inhibiting GABAAreceptors in vCA1.These findings support the hypothesis that LS inputs to the vCA1 can control social prefe rences and social novelty behaviors.These findings provide new insights rega rding the neural circuits that regulate sociability. 展开更多
关键词 chemogenetics GABA receptor GABAergic neurons glutamatergic neurons lateral septum neural excitability neural projection social novelty social preference ventral CA1
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Agricultural Investment Project Decisions Based on an Interactive Preference Disaggregation Model Considering Inconsistency
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作者 Xingli Wu Huchang Liao +1 位作者 Shuxian Sun Zhengjun Wan 《Computer Modeling in Engineering & Sciences》 SCIE EI 2024年第6期3125-3146,共22页
Agricultural investment project selection is a complex multi-criteria decision-making problem,as agricultural projects are easily influenced by various risk factors,and the evaluation information provided by decisionm... Agricultural investment project selection is a complex multi-criteria decision-making problem,as agricultural projects are easily influenced by various risk factors,and the evaluation information provided by decisionmakers usually involves uncertainty and inconsistency.Existing literature primarily employed direct preference elicitation methods to address such issues,necessitating a great cognitive effort on the part of decision-makers during evaluation,specifically,determining the weights of criteria.In this study,we propose an indirect preference elicitation method,known as a preference disaggregation method,to learn decision-maker preference models fromdecision examples.To enhance evaluation ease,decision-makers merely need to compare pairs of alternatives with which they are familiar,also known as reference alternatives.Probabilistic linguistic preference relations are employed to account for the presence of incomplete and uncertain information in such pairwise comparisons.To address the inconsistency among a group of decision-makers,we develop a pair of 0-1mixed integer programming models that consider both the semantics of linguistic terms and the belief degrees of decision-makers.Finally,we conduct a case study and comparative analysis.Results reveal the effectiveness of the proposed model in solving agricultural investment project selection problems with uncertain and inconsistent decision information. 展开更多
关键词 Multiple criteria analysis preference disaggregation INCONSISTENCY probability linguistic preference relation investment project selection
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Hydrologic Response to Future Climate Change in the Dulong-Irra-waddy River Basin Based on Coupled Model Intercomparison Project 6
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作者 XU Ziyue MA Kai +1 位作者 YUAN Xu HE Daming 《Chinese Geographical Science》 SCIE CSCD 2024年第2期294-310,共17页
Within the context of the Belt and Road Initiative(BRI)and the China-Myanmar Economic Corridor(CMEC),the Dulong-Ir-rawaddy(Ayeyarwady)River,an international river among China,India and Myanmar,plays a significant role... Within the context of the Belt and Road Initiative(BRI)and the China-Myanmar Economic Corridor(CMEC),the Dulong-Ir-rawaddy(Ayeyarwady)River,an international river among China,India and Myanmar,plays a significant role as both a valuable hydro-power resource and an essential ecological passageway.However,the water resources and security exhibit a high degree of vulnerabil-ity to climate change impacts.This research evaluates climate impacts on the hydrology of the Dulong-Irrawaddy River Basin(DIRB)by using a physical-based hydrologic model.We crafted future climate scenarios using the three latest global climate models(GCMs)from Coupled Model Intercomparison Project 6(CMIP6)under two shared socioeconomic pathways(SSP2-4.5 and SSP5-8.5)for the near(2025-2049),mid(2050-2074),and far future(2075-2099).The regional model using MIKE SHE based on historical hydrologic processes was developed to further project future streamflow,demonstrating reliable performance in streamflow simulations with a val-idation Nash-Sutcliffe Efficiency(NSE)of 0.72.Results showed that climate change projections showed increases in the annual precip-itation and potential evapotranspiration(PET),with precipitation increasing by 11.3%and 26.1%,and PET increasing by 3.2%and 4.9%,respectively,by the end of the century under SSP2-4.5 and SSP5-8.5.These changes are projected to result in increased annual streamflow at all stations,notably at the basin’s outlet(Pyay station)compared to the baseline period(with an increase of 16.1%and 37.0%at the end of the 21st century under SSP2-4.5 and SSP5-8.5,respectively).Seasonal analysis for Pyay station forecasts an in-crease in dry-season streamflow by 31.3%-48.9%and 22.5%-76.3%under SSP2-4.5 and SSP5-8.5,respectively,and an increase in wet-season streamflow by 5.8%-12.6%and 2.8%-33.3%,respectively.Moreover,the magnitude and frequency of flood events are pre-dicted to escalate,potentially impacting hydropower production and food security significantly.This research outlines the hydrological response to future climate change during the 21st century and offers a scientific basis for the water resource management strategies by decision-makers. 展开更多
关键词 climate change hydrologic response Coupled Model Intercomparison project 6(CMIP6) MIKE SHE(Système Hydrologique Europeén) Dulong-Irrawaddy River Basin
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Spatial Variation and Trend of Extreme Precipitation in Africa during 1981-2019 and Its Projected Changes at the End of 21st Century
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作者 Fabien Habiyakare Tong Jiang +3 位作者 Ibrahim Yahaya Daudi Ndabagenga James Kagabo Buda Su 《Journal of Geoscience and Environment Protection》 2024年第3期192-221,共30页
This study comprehensively examines the patterns and regional variation of severe rainfall across the African continent, employing a suite of eight extreme precipitation indices. The analysis extends to the assessment... This study comprehensively examines the patterns and regional variation of severe rainfall across the African continent, employing a suite of eight extreme precipitation indices. The analysis extends to the assessment of projected changes in precipitation extremes using five General Circulation Models (GCMs) from Coupled Model Intercomparison Project Phase 6 (CMIP6) under four Shared Socioeconomic Pathways (SSPs) scenarios at the long-term period (2081-2100) of the 21<sup>st</sup> century. Furthermore, the study investigates potential mechanisms influencing precipitation extremes by correlating extreme precipitation indices with oceanic system indices, specifically Ni?o 3.4 for El Ni?o-Southern Oscillation (ENSO) and Dipole Mode Index (DMI) for the Indian Ocean Dipole (IOD). The findings revealed distinct spatial distributions in mean trends of extreme precipitation indices, indicating a tendency toward decreased extreme precipitation in North Africa, Sahel region, Central Africa and the Western part of South Africa. Conversely, West Africa, East Africa and the Eastern part of South Africa exhibit an inclination toward increased extreme precipitation. The changes in precipitation extreme indices indicate a general rise in both the severity and occurrence of extreme precipitation events under all scenarios by the end of the 21<sup>st</sup> century. Notably, our analysis projects a decrease in consecutive wet days (CWD) in the far-future. Additionally, correlation analysis highlights significant correlation between above or below threshold rainfall fluctuation in East Africa and South Africa with oceanic systems, particularly ENSO and the IOD. Central Africa abnormal precipitation variability is also linked to ENSO with a significant negative correlation. These insights contribute valuable information for understanding and projecting the dynamics of precipitation extreme in Africa, providing a foundation for climate adaptation and mitigation efforts in the region. 展开更多
关键词 Extreme Precipitation Mann-Kendall Trend projections Oceanic system AFRICA
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Discussion on Construction Project Cost Budget Settlement Review
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作者 Hongfeng Liu Yumin Yuan 《Journal of Architectural Research and Development》 2024年第1期43-48,共6页
Construction project cost control involves many complex contents,forming a large amount of data information.If the processing method is unreasonable,it will likely affect the cost control efficiency.Therefore,in the c... Construction project cost control involves many complex contents,forming a large amount of data information.If the processing method is unreasonable,it will likely affect the cost control efficiency.Therefore,in the current construction project management,the review of project cost budget settlement is the focus to solve the cost management problems of construction projects and promote the development of the construction industry.This article mainly analyzes the influencing factors and current situation of construction project cost budget settlement review,and based on this,it explores the project cost budget settlement review strategy to promote the healthy development of construction project cost work. 展开更多
关键词 Construction project COST Budget settlement Review strategy
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Construction Safety Management of Mechanical and Electrical Installation Projects
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作者 Honglou Chi 《Journal of Architectural Research and Development》 2024年第2期50-54,共5页
Various industries today rely on the support of electromechanical equipment,expanding its scope of application and leading to an increase in electromechanical installation projects.However,due to the high level of exp... Various industries today rely on the support of electromechanical equipment,expanding its scope of application and leading to an increase in electromechanical installation projects.However,due to the high level of expertise required and the potential risks involved,it is crucial to emphasize safety management during construction.This paper delves into the significance of construction safety management for electromechanical installation projects,identifies common problems encountered during construction,and proposes solutions.This analysis aims to provide relevant personnel with essential guidance and references for managing electromechanical installation projects safely. 展开更多
关键词 Construction safety Mechanical and electrical installation Installation engineering Engineering projects Safety management
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Reform of Practical Teaching of “Linux Operating System Fundamentals” Under the Background of Emerging Engineering Education
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作者 Zhenhua Wang Chunli Chen Yuzhu Wang 《Journal of Contemporary Educational Research》 2024年第3期19-26,共8页
With the advancement of the construction of emerging engineering education,the reform of practical teaching has become an important task of higher engineering education.This article takes the course“Linux Operating S... With the advancement of the construction of emerging engineering education,the reform of practical teaching has become an important task of higher engineering education.This article takes the course“Linux Operating System Fundamentals”as an example to explore practical teaching reform in the context of emerging engineering education.By analyzing the current situation and problems in course practical teaching,we proposed practical teaching reforms such as online experiments,practical content updates,project-based engineering practices,and diversified evaluation models,and designed corresponding implementation plans.Practice has proved that this reform can improve students’learning interest and engineering practical skills,and cultivate outstanding engineers with innovative spirit and practical skills. 展开更多
关键词 Emerging engineering education Practical teaching reform project practice Virtual experiments
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Financial Calculation Problems and Countermeasure Analysis of Large-Scale Engineering Construction Projects
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作者 Qiong Hou 《Proceedings of Business and Economic Studies》 2024年第2期15-21,共7页
The financial aspects of large-scale engineering construction projects profoundly influence their success.Strengthening cost control and establishing a scientific financial evaluation system can enhance the project’s... The financial aspects of large-scale engineering construction projects profoundly influence their success.Strengthening cost control and establishing a scientific financial evaluation system can enhance the project’s economic benefits,minimize unnecessary costs,and provide decision-makers with a robust financial foundation.Additionally,implementing an effective cash flow control mechanism and conducting a comprehensive assessment of potential project risks can ensure financial stability and mitigate the risk of fund shortages.Developing a practical and feasible fundraising plan,along with stringent fund management practices,can prevent fund wastage and optimize fund utilization efficiency.These measures not only facilitate smooth project progression and improve project management efficiency but also enhance the project’s economic and social outcomes. 展开更多
关键词 Large-scale engineering construction projects Financial calculation Fund management
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Projected Changes in the Climate Zoning of Côte d’Ivoire
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作者 Mamadou Diarrassouba Adama Diawara +6 位作者 Assi Louis Martial Yapo Benjamin Komenan Kouassi Fidèle Yoroba Kouakou Kouadio Dro Touré Tiemoko Dianikoura Ibrahim Koné Arona Diedhiou 《Atmospheric and Climate Sciences》 2024年第1期62-84,共23页
This study assesses the projected changes in the climate zoning of Côte d’Ivoire using the hierarchical classification of principal components (HCPC) method applied to the daily precipitation data of an ensemble... This study assesses the projected changes in the climate zoning of Côte d’Ivoire using the hierarchical classification of principal components (HCPC) method applied to the daily precipitation data of an ensemble of 14 CORDEX-AFRICA simulations under RCP4.5 and RCP8.5 scenarios. The results indicate the existence of three climate zones in Côte d’Ivoire (the coastal, the centre and the north) over the historical period (1981-2005). Moreover, CORDEX simulations project an extension of the surface area of drier climatic zones while a reduction of wetter zones, associated with the appearance of an intermediate climate zone with surface area varying from 77,560 km<sup>2</sup> to 134,960 km<sup>2</sup> depending on the period and the scenario. These results highlight the potential impacts of climate change on the delimitation of the climate zones of Côte d’Ivoire under the greenhouse gas emission scenarios. Thus, there is a reduction in the surface areas suitable for the production of cash crops such as cocoa and coffee. This could hinder the country’s economy and development, mainly based on these cash crops. 展开更多
关键词 Climate projection Climate Zone Principal Component Analysis Hierarchical Classification on Principal Components CORDEX Côte d’Ivoire
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核心素养视域下高中英语Project板块有效教学模式探究
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作者 高瑞 《安徽教育科研》 2024年第12期41-44,共4页
分析人教版高中英语教材Project板块教学过程中存在的弊端和问题,结合具体教学实际,从Planning, Preparing, Producing, Presenting和Progressing五个环节探究人教版高中英语教材Project板块的教学模式的创新及有效性。高中英语project... 分析人教版高中英语教材Project板块教学过程中存在的弊端和问题,结合具体教学实际,从Planning, Preparing, Producing, Presenting和Progressing五个环节探究人教版高中英语教材Project板块的教学模式的创新及有效性。高中英语project板块的教学有助于提升语言能力,拓展思维方式;增强文化意识,培养正确价值观;发展思维品质,树立主体意识。在教学过程中,教师应合理利用好教材资源,把课堂交还给学生,突出学生学习的主体性,设计行之有效的教育教学活动和模式、科学的评价方法,从而从整体上培养学生的英语学科核心素养。 展开更多
关键词 核心素养 人教版高中英语教材 project板块 有效教学模式
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Consensus Control With a Constant Gain for Discrete-time Binary-valued Multi-agent Systems Based on a Projected Empirical Measure Method 被引量:4
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作者 Ting Wang Min Hu Yanlong Zhao 《IEEE/CAA Journal of Automatica Sinica》 SCIE EI CSCD 2019年第4期1052-1059,共8页
This paper studies the consensus control of multiagent systems with binary-valued observations.An algorithm alternating estimation and control is proposed.Each agent estimates the states of its neighbors based on a pr... This paper studies the consensus control of multiagent systems with binary-valued observations.An algorithm alternating estimation and control is proposed.Each agent estimates the states of its neighbors based on a projected empirical measure method for a holding time.Based on the estimates,each agent designs the consensus control with a constant gain at some skipping time.The states of the system are updated by the designed control,and the estimation and control design will be repeated.For the estimation,the projected empirical measure method is proposed for the binary-valued observations.The algorithm can ensure the uniform boundedness of the estimates and the mean square error of the estimation is proved to be at the order of the reciprocal of the holding time(the same order as that in the case of accurate outputs).For the consensus control,a constant gain is designed instead of the stochastic approximation based gain in the existing literature for binary-valued observations.And,there is no need to make modification for control since the uniform boundedness of the estimates ensures the uniform boundedness of the agents’states.Finally,the systems updated by the designed control are proved to achieve consensus and the consensus speed is faster than that in the existing literature.Simulations are given to demonstrate the theoretical results. 展开更多
关键词 Binary-valued observations CONSENSUS CONTROL CONSTANT GAIN convergence rate multi-agent systems projected empirical measure method
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Study on Method of Comprehensive Evaluating for Information System Projects 被引量:2
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作者 Xu, Weixiang Zhang, Quanshou 《Journal of Systems Engineering and Electronics》 SCIE EI CSCD 2000年第2期17-24,共8页
In this paper, a new method of evaluation for information system project is proposed on the basis of the meta-synthesis methodology from qualitative analysis to quantitative analysis.DHGF is an integrated method of im... In this paper, a new method of evaluation for information system project is proposed on the basis of the meta-synthesis methodology from qualitative analysis to quantitative analysis.DHGF is an integrated method of improved Delphi, analytic hierarchy process, grey interconnect degree and fuzzy comprehensive evaluating. It gives full play to their advantages and controls theirs disadvantages. The feasibility and effectiveness of DHGF are shown in the practical example. 展开更多
关键词 METHODOLOGY INFORMATION system projectS A META-SYNTHESIS of DHGF COMPREHENSIVE EVALUATING
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Generalized Projective Synchronization of Fractional Order Chaotic Systems with Different Dimensions 被引量:2
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作者 王莎 于永光 《Chinese Physics Letters》 SCIE CAS CSCD 2012年第2期44-46,共3页
The generalized projective synchronization of different dimensional fractional order chaotic systems is investigated.According to the stability theory of linear fractional order systems,a sufficient condition to reali... The generalized projective synchronization of different dimensional fractional order chaotic systems is investigated.According to the stability theory of linear fractional order systems,a sufficient condition to realize synchronization is obtained.The fractional order chaotic and hyperchaotic systems are applied to achieve synchronization in both reduced and increased dimensions.The corresponding numerical results coincide with theoretical analysis. 展开更多
关键词 CHAOTIC FRACTIONAL projectIVE
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基于Projection VOF方法的熔模铸造蜡模充型过程数值模拟 被引量:2
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作者 杨铭 廖敦明 +2 位作者 陈宇豪 陈涛 顾建华 《铸造》 CAS 北大核心 2023年第2期107-114,共8页
针对熔模铸造蜡模充型过程数值模拟软件自主开发,建立了流动场和温度场数学模型,采用Cross-WLF粘度模型描述蜡料的流变性能,基于Projection VOF方法进行蜡料流动过程速度场、压力场以及自由表面的求解。通过试验测量获取了K512型蜡料的... 针对熔模铸造蜡模充型过程数值模拟软件自主开发,建立了流动场和温度场数学模型,采用Cross-WLF粘度模型描述蜡料的流变性能,基于Projection VOF方法进行蜡料流动过程速度场、压力场以及自由表面的求解。通过试验测量获取了K512型蜡料的热物理性能和流变性能的相关数据,拟合得到粘度模型参数。分别在蜡料常粘度和变粘度模型两种条件下对扳机铸件蜡模充型过程进行模拟,结果表明,所建立蜡模充型过程数学模型能较好地描述蜡料的动态流变特性和传热行为。 展开更多
关键词 熔模铸造 蜡模充型 数值模拟 projection VOF方法
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A system dynamics model for billion trees tsunami afforestation project of Khyber Pakhtunkhwa in Pakistan:Model application to afforestation activities 被引量:1
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作者 Naila NAZIR Aqsa FAROOQ +1 位作者 Sajjad AHMAD JAN Aftab AHMAD 《Journal of Mountain Science》 SCIE CSCD 2019年第11期2640-2653,共14页
As part of the global effort to plant billion trees,an afforestation project is launched in Pakistan in Khyber Pakhtunkhwa(KP)province to conserve existing forests and to increase area under forest cover.The present s... As part of the global effort to plant billion trees,an afforestation project is launched in Pakistan in Khyber Pakhtunkhwa(KP)province to conserve existing forests and to increase area under forest cover.The present study is designed to build a Systems'model by incorporating major activities of the Billion Tree Tsunami Afforestation Project(BTTAP)with special focus on afforestation activities to estimate the growth in forest area of KP.Availability of complete dataset was a challenge.To fix the model,the raw data taken from the project office has been utilized.Planning Commission Form 1-Phase I&II helped us with additional information.We relied on the data available for one and half period of the project as rest of the data is subject to the completion of the project.Our results show that the project target to enhance area under forest differs from the target to afforest area under the project.The system dynamics'model projection shows that the forest area of KP would be 23.59 million hectares at the end of the BTTA project,thus having an increase of 3.29%instead of 2%that has been initially proposed.However,the results show that the progress to meet the target in some afforestation classes is slow as compared to other categories.Farm forestry,plantation on communal lands and owners'plantation need special focus of the authority.Deforestation would affect 0.02 million hectares area of the project.The model under study may be used as a reference model that can be replicated to other areas where billion tree campaigns are going on. 展开更多
关键词 Billion trees project AFFORESTATION system dynamic model FOREST area DEFORESTATION Pakistan
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