期刊文献+
共找到39篇文章
< 1 2 >
每页显示 20 50 100
曲面片的可展度及其最佳展开基点 被引量:10
1
作者 毛昕 《工程图学学报》 CSCD 1998年第2期1-11,共11页
本文通过对不可展曲面近似展开误差机理的分析研究,提出了曲面片最佳展开基点和曲面片可展度的概念和实现方法,研制了曲面展开和误差分析计算机辅助系统。实验证明,展开基点的选取和可展度的判别是提高曲面片展开精度的重要因素。
关键词 曲面 最佳开基点 可展度 开图
下载PDF
曲面片的可展性能及其应用 被引量:4
2
作者 毛昕 马明旭 王哲英 《工程图学学报》 CSCD 2002年第2期133-138,共6页
通过对曲面片可展性能及其应用的研究,在文献[1]的基础上更准确地给出了用可展度定量度量曲面片可展性能的概念和方法,同时给出了可展度在不可展曲面近似展开中的应用。一方面可以在曲面展开之前估计近似展开的误差,从而合理选择展开范... 通过对曲面片可展性能及其应用的研究,在文献[1]的基础上更准确地给出了用可展度定量度量曲面片可展性能的概念和方法,同时给出了可展度在不可展曲面近似展开中的应用。一方面可以在曲面展开之前估计近似展开的误差,从而合理选择展开范围;另一方面,基于最佳展开基点均匀分割曲面片可展度的假设,实现了近似展开中最佳展开基点的选取。 展开更多
关键词 曲面性 可展曲面 可展性能 可展度 开基点
下载PDF
曲面片可展性能的研究
3
作者 卢艳军 李滨慧 《辽宁省交通高等专科学校学报》 2000年第1期6-8,14,共4页
本文通过对曲面片近似展开误差的分析研究,提出了曲面片可展度的概念,且在理论上对其进行了推导,并对其工程应用作了较为详细的叙述。
关键词 公路曲面 开精 可属性能 可展度
下载PDF
Landscape Design Method of Sustainable Development Based on the Modest Principle
4
作者 许克福 龚杰 《Agricultural Science & Technology》 CAS 2016年第3期717-720,共4页
"Over" phenomenon exists in all fields of society, and over thoughts and behaviors not only waste resources, but also destroy the ecological environment.Landscape design is also facing the dilemma of over planning, ... "Over" phenomenon exists in all fields of society, and over thoughts and behaviors not only waste resources, but also destroy the ecological environment.Landscape design is also facing the dilemma of over planning, over design and over construction. Based on the paraphrase and explanation of "degree", the principle for modest landscape design with the concept of sustainable development was explored through the analysis on the concept of sustainable development, which emphasized the "degree" standard in landscape design, and the combination of regional features with native features to carry out ecological design, with the aim to facilitate the landscape designers to design the "modest" landscape with sustainable development. 展开更多
关键词 Over-design Sustainable development Landscape design MODEST Ecological design
下载PDF
Adaptive clustering hierarchy routing for delay tolerant network 被引量:2
5
作者 陶勇 王晓方 《Journal of Central South University》 SCIE EI CAS 2012年第6期1577-1582,共6页
Adaptive clustering hierarchy routing(ACHR) establishes a clusters-based hierarchical hybrid routing algorithm with two-hop local visibility for delay tolerant network(DTN).The major contribution of ACHR is the combin... Adaptive clustering hierarchy routing(ACHR) establishes a clusters-based hierarchical hybrid routing algorithm with two-hop local visibility for delay tolerant network(DTN).The major contribution of ACHR is the combination of single copy scheme and multi-copy scheme and the combination of hop-by-hop and multi-hop mechanism ACHR,which has the advantages in simplicity,availability and well-expansibility.The result shows that it can take advantage of the random communication opportunities and local network connectivity,and achieves 1.6 times delivery ratio and 60% overhead compared with its counterpart. 展开更多
关键词 delay tolerant network routing scheme congestion control hierarchy routing
下载PDF
Circular economy: from an institutional perspective 被引量:1
6
作者 Lu Jingchao 《Ecological Economy》 2007年第2期114-121,共8页
Circular economy (CE) has been put fonvard as an important environmental and resource strategy in China.Aiming at the high utilization rate of resources and reduction of pollutants,CE means to realize a shift of fun... Circular economy (CE) has been put fonvard as an important environmental and resource strategy in China.Aiming at the high utilization rate of resources and reduction of pollutants,CE means to realize a shift of fundamental paradigm.With the mode of production and consumption from linear to recycling model,the promotion requires transdisciplinary researches which integrate technological,ecological,social-cultural and other sciences.The present study focuses on the implementation of circular economy from an institutional perspective.Institution acts as a crucial factor by providing incentives for technical innovation,leading investment orientation and determining policy effectiveness,etc.This paper mainly discusses about: firstly,the feature of institution,institutional changes and institutional innovation is articulated,together with eco-industrial park strategy,extended producer's responsibility and dematerialization principle as innovative institutional arrangements; secondly,as policy plays great role on institutional changing process,the mechanism of policy implementation is needed to be related; as a result,coevolution of institutions and policies is thus presented; at last,a pilot attempt is made to find out some operational avenues in accomplishment of CE through both theoretical and practical methodology,special resolutions are put forward after some projecting difficulties and dilemmas in China are described. 展开更多
关键词 Circular economy Institutional innovation Policy effectiveness Coevolution
下载PDF
Paradigm and Ecological Implication of Changing Agricultural Land-use:A Case Study from Govind Wildlife Sanctuary,Central Himalaya,India 被引量:3
7
作者 Vikram S.NEGI Rakesh K.MAIKHURI Lakhpat S.RAWAT 《Journal of Mountain Science》 SCIE CSCD 2012年第4期547-557,共11页
The paper scrutinizes that the changes in any sub-system(i.e.agriculture,livestock and forest) have direct impact on biophysical and social processes in village ecosystem of the central Himalayan region.In view of thi... The paper scrutinizes that the changes in any sub-system(i.e.agriculture,livestock and forest) have direct impact on biophysical and social processes in village ecosystem of the central Himalayan region.In view of this,we studied the changes in spatial patterns of agricultural land use and dependency of agroecosystem on forest and animal husbandry over a period of two decades.Based on data analysis it was found that the cultivation of some traditional crops has either been abandoned in the area or declined by 25%-85% due to introduction of cash crops viz.,potato,kidney bean and apple farming with acreage increased up to 51%-72% in the last three decades.Livestock population of different categories has declined drastically by 17%-75%,and has resulted shortage of farmyard manure,deterioration of soil quality and fertility which leads to un-sustainability of agriculture system.The changes in agrobiodiversity have led to the dramatic increase in soil loss and runoff from the croplands together with the increase pressure on forests.The economic evaluation of each crop showed higher monetary benefit from cash crops as compared to traditional crops.Among all the evaluated crops,the monetary output/input ratio was found highest(3.04) for kidney bean and lowest(1.26) for paddy.Changes in land use and management have improved household income but at the cost of forest degradation,less productive animal husbandry and loss of agrodiversity in the region.Therefore,there is an urgent need to bring desirable changes in agricultural policy,research,land use and efficient management of the resources for maintaining sustainability in agro and Himalayan forest ecosystem. 展开更多
关键词 Forest Animal husbandry Cash crop Traditional agrodiversity Sustainability
下载PDF
Computational Performance of the High-Resolution Atmospheric Model FAMIL 被引量:8
8
作者 ZHOU Lin-Jiong LIU Yi-Min +2 位作者 BAO Qing YU Hai-Yang WU Guo-Xiong 《Atmospheric and Oceanic Science Letters》 2012年第5期355-359,共5页
This paper describes the model speed and model In/Out (I/O) efficiency of the high-resolution atmospheric general circulation model FAMIL (Finite- volume Atmospheric Model of IAP/LASG) at the National Supercompute... This paper describes the model speed and model In/Out (I/O) efficiency of the high-resolution atmospheric general circulation model FAMIL (Finite- volume Atmospheric Model of IAP/LASG) at the National Supercomputer Center in Tianjin, China, on its Tianhe-lA supercomputer platform. A series of three- model-day simulations were carried out with standard Aqua Planet Experiment (APE) designed within FAMIL to obtain the time stamp for the calculation of model speed, simulation cost, and model 1/O efficiency. The results of the simulation demonstrate that FAMIL has remarkable scalability below 3456 and 6144 cores, and the lowest simulation costs are 1536 and 3456 cores for 12.5 km and 6.25 krn resolutions, respectively. Furthermore, FAMIL has excellent I/O scalability and an efficiency of more than 80% on 6 I/Os and more than 99% on 1536 I/Os. 展开更多
关键词 FAMIL HIGH-RESOLUTION computational per-formance SCALABILITY EFFICIENCY
下载PDF
A Comprehensive Evaluation of Tourism Climate Suitability in Qinghai Province, China 被引量:11
9
作者 TANG Chengcai ZHONG Linshen +1 位作者 KRISTEN McDonald CHENG Shengkui 《Journal of Mountain Science》 SCIE CSCD 2012年第3期403-413,共11页
Qinghai Province is an important component of the Qinghai-Tibet Plateau in China. Scientific evaluation of the suitability of Qinghai's climate for tourism can contribute to overcoming obstacles posed by climate o... Qinghai Province is an important component of the Qinghai-Tibet Plateau in China. Scientific evaluation of the suitability of Qinghai's climate for tourism can contribute to overcoming obstacles posed by climate on sustainable tourism development in Qinghai Province, including disparities between the low and high seasons, high altitude health concerns, and weather events. A tourism climate suitability evaluation model of the Qinghai-Tibet Plateau is constructed (Tourism Climate Suitability Index, or TCSI), and tourism climate suitability is comprehensively evaluated for Qinghai Province from climate data from 1960 to 2009. Results show that: (I) There is clear distributional characteristics of spatial-temporal variability of TCSI values in Qinghai Province. (II) Tourism climate suitability in Qinghai Province has significant seasonal and regional differences. The year is divided into a very suitable period (July and August), suitable tourism periods (from April and October), less suitable periods (From Nov to Mar). June to August is the most suitable tourism period in Qinghai. Qinghai Province is divided into five levels of tourism climate suitability: most suitable regions, very suitable regions, suitable regions, less suitable regions, and unsuitable region. (III) The key factor which influences regional differences in tourism climatic suitability is atmospheric oxygen. And the key factors which chiefly influence seasonal differences of tourism climate suitability are temperature and humidity, the wind chill factor, and barrier weather. 展开更多
关键词 Tourism climate Tourism climatesuitability index (TCSI) Comprehensive evaluation Qinghai Province Qinghai-Tibet Plateau China
下载PDF
Non-coordination in China′s Urbanization: Assessment and Affecting Factors 被引量:26
10
作者 SUN Pingjun SONG Wei +1 位作者 XIU Chunliang LIANG Zhenming 《Chinese Geographical Science》 SCIE CSCD 2013年第6期729-739,共11页
Urbanization is a comprehensive concept, a trinity process that population urbanization, economic urbanization and space urbanization, is based on the interactions and mutual influences among the in which, people are ... Urbanization is a comprehensive concept, a trinity process that population urbanization, economic urbanization and space urbanization, is based on the interactions and mutual influences among the in which, people are the central and leading players in this process, while economic activities serve as the driving force and space is the carrier-the physical or material setting as well as the product. So the coordination among these processes is crucial for a country or region's sustainable development. China is experiencing rapid growth of cities and a surge in urban population, with the basic national condition of many people and little land, which calls for a systematic study of the issue of coordinated urbanization from theoretical, methodological and practical perspectives. Based on the concept of urbanization and non-coordination of urbanization, this article built a quantitative method to identify and evaluate the urbanization and non-coordination of urbanization, and made an empirical analysis in China between 2000 and 2008. The results show that the non-coordination overall level of China's urbanization declined during the study period, because population urbanization, economic urbanization, and space urbanization exhibited different trajectories of change. This study also reveals that performance assessment system, household registration system, and urban land expropriation system, etc., are the main affecting factors. At the end, we put forward some suggestions to achieve sustainable development of China's urbanization from the aspects of improving the local government's obiective function, imolementing the urban plalming svstem, enforcing public particination asnects and so on. 展开更多
关键词 non-coordination of urbanization coordinated development degree China
下载PDF
Ultra-High Strength Concrete Mixtures Using Local Materials 被引量:6
11
作者 Srinivas Allena Craig M. Newtson 《Journal of Civil Engineering and Architecture》 2011年第4期322-330,共9页
This paper presents the development of ultra high strength concrete (UHSC) using local materials. UHSC mixture proportions were developed using local materials so that UHSC may be made more affordable to a wider var... This paper presents the development of ultra high strength concrete (UHSC) using local materials. UHSC mixture proportions were developed using local materials so that UHSC may be made more affordable to a wider variety of applications. Specifically, local sand with a top size of 600 um, and locally available Type I/II cement and silica fume were used in this research. Each of these material selections is seen as an improvement in sustainability for UHSC. Two mixtures (one with and one without fibers) were recommended as the UHSC mixtures. The greatest compressive strengths obtained in this study were 165.6 MPa for UHSC with steel fibers and 161.9 MPa for UHSC without fibers. The compressive and flexural strengths obtained from the UHSC mixtures developed in this work are comparable to UHSC strengths presented in the literature. Producing this innovative material with local materials reduces the cost of the material, improves sustainability, and produces mechanical performance similar to prepackaged, commercially available products. 展开更多
关键词 Compressive strength local materials modulus of rupture SUSTAINABILITY ultra-high strength
下载PDF
Complexity scalable control algorithm for intra coding in H.264 under energy constraints
12
作者 Gao Xuejun Lam Kin Man +1 位作者 ZhuoLi ShenLansun 《High Technology Letters》 EI CAS 2010年第3期274-279,共6页
In this paper, the complexity of intra coding is first analyzed so as to achieve a weight of complexity measurement for each intra mode. Then, a new complexity scalable control algorithm for intra coding in H. 264 is ... In this paper, the complexity of intra coding is first analyzed so as to achieve a weight of complexity measurement for each intra mode. Then, a new complexity scalable control algorithm for intra coding in H. 264 is proposed, based on the rearrangement of the order of candidate modes and an efficient complexity allocation and control (CAAC) scheme at the macroblock (MB) level. The candidate modes of each MB are rearranged according to the local-edge information. Experimental results show that our proposed algorithm can make an appropriate cut-off point of the candidate modes sequence adaptively according to the current energy condition of a mobile device, so as to adjust the complexity at any level while maximizing the video quality, which can prolong the operational lifetime of the battery with minimum degradation in video quality. 展开更多
关键词 complexity scalable control complexity allocation rearrangement of candidate modes intra coding H. 264 energy constraints
下载PDF
Dynamic assets allocation based on market microstructure model with variable-intensity jumps
13
作者 覃业梅 彭辉 《Journal of Central South University》 SCIE EI CAS 2014年第3期993-1002,共10页
In order to characterizc large fluctuations of the financial markets and optimize financial portfolio, a new dynamic asset control strategy was proposed in this work. Firstly, a random process item with variable jump ... In order to characterizc large fluctuations of the financial markets and optimize financial portfolio, a new dynamic asset control strategy was proposed in this work. Firstly, a random process item with variable jump intensity was introduced to the existing discrete microstructure model to denote large price fluctuations. The nonparametric method of LEE was used for detecting jumps. Further, the extended Kalman filter and the maximum likelihood method were applied to discrete microstructure modeling and the estimation of two market potential variables: market excess demand and liquidity. At last, based on the estimated variables, an assets allocation strategy using evolutionary algorithm was designed to control the weight of each asset dynamically. Case studies on IBM Stock show that jumps with variable intensity are detected successfully, and the assets allocation strategy may effectively keep the total assets growth or prevent assets loss at the stochastic financial market. 展开更多
关键词 discrete microstrucmre model (DMSM) variable jump intensity evolutionary algorithm (EA) asset allocation excess demand market liquidity
下载PDF
“We are all in the same boat”-ISEE leaders’ trip to China
14
《Ecological Economy》 2007年第3期F0002-F0002,共1页
The motto of Tongji University, whose name literally means "we are all in the same boat, and must work together to reach common goals", describes the harvest of ISEE leaders' mission to China in May 2007. ISEE Pres... The motto of Tongji University, whose name literally means "we are all in the same boat, and must work together to reach common goals", describes the harvest of ISEE leaders' mission to China in May 2007. ISEE President Joan Martinez-Alier, President-Elect Peter May and the society's founder and first President, Robert Costanza as well as ISEE member Robert Ayres, participated in a series of events and meetings in Shanghai and Beijing with a view to build institutional collaboration. 展开更多
关键词 Sustainable Development institutional collaboration collaborative venture ecological ecnomic
下载PDF
MEXIR: An Implementation of High Performance and High Precision on XML Retrieval
15
作者 Tanakom Wichaiwong Chuleerat Jaruskulchai 《Computer Technology and Application》 2011年第4期301-310,共10页
Traditional information retrieval systems respond to user queries with ranked lists of relevant documents. Since, XML (Extensible Markup Language) documents separate content and structure; XML-IR (information retri... Traditional information retrieval systems respond to user queries with ranked lists of relevant documents. Since, XML (Extensible Markup Language) documents separate content and structure; XML-IR (information retrieval) systems are able to retrieve only the relevant portions of documents. Therefore, users who utilize an XML-IR system could potentially receive highly relevant and precise material. We have developed the XML information retrieval system by using MySQL and Sphinx, which we call MEXIR. In our system, XML documents are stored into one table that has fixed relational schema. The schema is independent of the logical structure of XML documents. Each node in XML documents is represented by labels that express the positions in XML tree, namely ADXPI scheme. Our system has performance experiments on INEX collections and shown an average up to four seconds better than GPX. In addition, it has been reduced the size of the data down by 82.29 % compare to GPX system. 展开更多
关键词 XML retrieval information retrieval ranking strategies indexing units.
下载PDF
Ecological Democracy and Sustainability in Fragile Environment: Environmental Discourse in Select Pieces of Environmental Writing from India
16
作者 Parameswaran Leela Suja Kurup 《Journal of Earth Science and Engineering》 2014年第6期361-371,共11页
Environmental writing has attained a new relevance in the 21st century. In the present scenario, environmental writing becomes a social discourse. This is the result of a new, vibrant and growing environmental constit... Environmental writing has attained a new relevance in the 21st century. In the present scenario, environmental writing becomes a social discourse. This is the result of a new, vibrant and growing environmental constituency in societies such as Brazil, India, Thailand and other Third World Countries. The features of environmental writing include a visible concern for social justice, defence of livelihood and the determining part played by women. This new discourse has emerged with a new focus on redefinition of terms like human rights, common good, democracy and CPRs (common property resources). Environmental Writing becomes a powerful discourse when it protests against the increasingly intrusive and interventionist developmental projects, implemented by the government, which in turn assert dominion over indigenous people of the land. There is also a strong emphasis on prudence among the poor as contrasted to the ecological profligacy of the rich. This paper is an attempt to examine the voices of dissent and the accountability of postmodern writers and environmental activists in India regarding environmental issues in India. 展开更多
关键词 Ecological democracy sustainable development stakeholders in natural resources women and conservation community conservation need-based rural development.
下载PDF
Using Geospatial Information Systems in Analyzing Urbanization Impacts on Stream Habitats in Southern Mississippi Coastal Ecosystem
17
作者 E. Merem S. Yerramilli +6 位作者 C. Richardson J. Wesley T. Walker D. Foster J. Williams C. Romamo E Nwagboso 《Journal of Environmental Science and Engineering》 2011年第12期1624-1641,共18页
The proliferation of urban development with concentration in population and human-environment interaction has intensified around urban environments. This has resulted in the degradation of urban environments, overuse ... The proliferation of urban development with concentration in population and human-environment interaction has intensified around urban environments. This has resulted in the degradation of urban environments, overuse of natural resources and widespread pollution of ecosystems, The patterns of design initiatives continue to follow unsustainable path with impacts on stream ecosystems. Accordingly, the paper adopts geospatial information systems and sustainability principles for the identification and sequential mapping of stressors impeding natural systems in Southern Mississippi. The results not only reveal that the study area experienced some significant changes in its watershed environments, but the stream habitat ecosystem remains under stress. The recommendations for mitigating the problems range from policy considerations to the adoption of ecosystem approach. 展开更多
关键词 Geospatial information systems URBANIZATION ecological design ecosystem approach environmental degradation.
下载PDF
Innovation of concept and system of economic law based on the sustainable development
18
作者 Jun ZHAO 《International Journal of Technology Management》 2014年第12期4-6,共3页
Make up for deficiencies in the economic development of market mechanisms through macro-control method. Although the market plays a fundamental role in resource allocation, in other means of regulation it plays an irr... Make up for deficiencies in the economic development of market mechanisms through macro-control method. Although the market plays a fundamental role in resource allocation, in other means of regulation it plays an irreplaceable role in regulating the economy, the management of economic activities. However, by the market "invisible hand" spontaneous adjustment, there is "market failure" problem. Market self-regulation mechanisms inevitable cyclical economic fluctuations and economic crisis, the impact of a sustained and stable economic growth will lead to a waste of resources, environmental degradation is caused, but also it produces uneven regional development, causing social polarization between rich and poor, etc. Public goods such as ecological environment should be through legal means, rather than a means to implement the healthy development of the market environment. 展开更多
关键词 LAW VALUES FAIR efficiency sustainable development
下载PDF
Sustainability of Urban Lakes: Role of Values in Lake Governance in Ahmedabad, India
19
作者 Mansee Bal Jacko Anthonie Van Ast Jaap Bouma 《Sociology Study》 2013年第3期182-206,共25页
Lakes have different social, economical, and ecological values at different periods of societal development, which make them vulnerable to change. One of the ongoing discussions in urban lake governance in India is th... Lakes have different social, economical, and ecological values at different periods of societal development, which make them vulnerable to change. One of the ongoing discussions in urban lake governance in India is the revitalization of the urban lakes. The core challenge documented in the governance of urban lakes is to address and find balance in the changing and competing value systems. Effectively addressing the change (or priority) in the values linked to the governance systems is a major step toward sustainability of the urban lakes. There is still limited understanding of how the values of urban lakes are progressively linked to the social, ecological and economic values of the urban developments. The paper looks at the interactions and outcomes of the spatial and temporal dynamics of the urban lakes systems especially the values that sustain the institutional and ecological memory. The focus is on the role of values in urban lake governance. The multitier framework for analyzing social-ecological systems CSES) which is in developmental phase at Elinor Ostrom's Workshop is used as the guiding framework to build understanding of the urban lake governance in Ahmedabad, India and at the same time contribute to the development of the SES framework. 展开更多
关键词 SUSTAINABILITY urban lakes VALUES GOVERNANCE Ahmedabad
下载PDF
Sustainability of China's Tax Revenue Growth: Experience and Prospect
20
作者 王道树 《China Economist》 2012年第6期100-109,共10页
This paper summarizes the main characteristics of China's tax revenue growth during the period of 1994-2010, and probes the causes behind the sustained and rapid growth of China's taxation from its sources including... This paper summarizes the main characteristics of China's tax revenue growth during the period of 1994-2010, and probes the causes behind the sustained and rapid growth of China's taxation from its sources including the fiscal and taxation system, and tax collection mechanisms. Additionally, the author lists the major challenges confronting China's sustainable tax growth during the "12th Five-Year Plan "period (2011-2015), for example, slowed growth in sources of taxation, a mismatched tax system, lagging reform in fiscal structure and the management system, and restrictions in tax collection and administration capacity. The author proposes the following suggestions: 1) a structural taxation reform should be carried out to promote sustainable economic growth and a change in development model, thereby consolidating the source base of taxation; 2) to consolidate the fiscal and taxation system through taxes and fees reform, standardizing the government budget, advancing reform in the tax-sharing system, and optimizing fiscal expenditure; and 3) to strengthen tax collection mechanisms by promoting taxation by law, implementing comprehensive taxation administration in the government, and improving the tax collection capacity. 展开更多
关键词 TAX sustainable growth tax reform fiscal system tax collection and administration
下载PDF
上一页 1 2 下一页 到第
使用帮助 返回顶部