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1.
Thinking about future needs and about what can reasonably be expected as feasible in the next century, how should producers of statistics direct their activity? Increasing complexity and diversity of needs leads us to recognize that, between producers and users of statistics, a mediating role is more and more often played by analysts and research workers who are requesting above all good data bases. Concerning infrastructures for statistics on productive systems, coordination between accountants and statisticians will be crucial, as well as adaptation of the constraints which, because of excessive worry about confidentiality, could prevent establishment or use of data bases. In an increasingly competitive world, where private firms will sell analyses and informations, particularly on very large enterprises, the public statistical service will remain essential in all respects. Intangible investments, innovations and many aspects of the internal organization of firms will create formidable challenges. Information on employment and labour markets has been much developed during the past decades; but on a few specific and difficult issues progress is still needed: lifecyles in the working-age population, acquisition of knowledge and skills in formal education and on the job, matching labour supplies and demands, and so on. Particular attention will have to be given to the lower levels of cultural and professional skills.  相似文献   
2.
采用预失真技术对功率放大器的记忆非线性失真进行补偿的关键是预失真器建模的准确性,尤其是模型对功率放大器逆记忆特性的描述能力。针对目前预失真器模型对功率放大器逆记忆效应描述不充分的问题,提出了将查找表(LUT)级联一个具有并联结构的有限长单位冲激响应(FIR)滤波器组作为实现形式的Hammerstein预失真器,以提高传统Hammerstein预失真器的补偿性能,并采用一种两步算法对其参数进行辨识。仿真实验表明,提出的Hammerstein预失真器能更好地补偿带强记忆效应的功率放大器的非线性失真。  相似文献   
3.
绿洲系统"三生"承载力驱动机制与模式的理论探讨   总被引:3,自引:0,他引:3  
张传国  刘婷 《经济地理》2003,23(1):83-87
以全新的视角解释了绿洲系统生态-生产-生活承载力的内涵,从生态、经济与社会效益的角度分别以水资源、投资作为驱动因子分析了绿洲系统“三生”承载力的驱动机制,阐明了人口在绿洲系统“三生”承载力驱动机制中的双重作用。水资源、投资与人口共同影响着绿洲系统“三生”承载力的模式类型与更替机理,绿洲系统“三生”承载力模式类型的科学界定,对合理开发绿洲系统具有重要现实意义。  相似文献   
4.
This paper deals with the collective qualification of members of society as belonging to a certain category or group based on a fixed attribute. Our model contains three main features: the existence of individual gradual opinions, the notion of elitism (only the opinions of certain individuals are taken into account to delineate the reference group), and the idea of sequentiality (elites are successively created by using the previous elites’ opinions on a social decision scheme). The main results of the paper characterize when this sequential procedure converges for some intuitive ways of aggregating individual opinions. Finally, we analyze the role of convergence for two extra basic properties (symmetry and contractiveness) that elitist rules should possess.  相似文献   
5.
在自我决定理论的基础上探讨高绩效工作系统对不同动机员工沉默行为的影响机制及差异性。研究结果表明:(1)高绩效工作系统对员工默许沉默、防御沉默和漠视沉默行为具有显著的抑制作用;(2)高绩效工作系统能通过自主需求满意度、能力需求满意度和关系需求满意度的提升降低员工的默许沉默行为;(3)高绩效工作系统能通过关系需求满意度的提升降低员工的防御沉默行为;(4)高绩效工作系统通过自主需求满意度、能力需求满意度和关系需求满意度的提升降低员工的漠视沉默行为。  相似文献   
6.
章杰宽 《科学决策》2013,(12):27-39
区域旅游可持续发展涉及诸多关键性的要素和指标,同时这些要素与指标之间又存在着错综复杂的关联。因此,在学科交叉研究越发普及的趋势下,文章基于复杂系统观,以西藏自治区旅游可持续发展为研究对象,分析了西藏旅游可持续发展系统的内部结构、功能及其运行机理。在此基础上,文章进一步讨论了区域旅游可持续发展研究中复杂网络研究范式的实用性,并就复杂网络范式在西藏旅游可持续发展研究中的相关应用谈了些基本看法。最后,文章认为,抛开西藏旅游可持续发展的特殊性,复杂系统与复杂网络研究也应成为未来可持续旅游研究的重要范式。  相似文献   
7.
该文对语音编辑播放系统的目前应用状况和未来的发展趋势进行了详细的分析,并对文语转换系统的结构组成和工作原理作了明确的说明,最后通过一个具体的案例:在VB调用TTS技术实现语音的编辑和播放,说明TTS技术的开发过程.  相似文献   
8.
Consistent with the challenges of sustainability science, land architecture offers a comprehensive approach to land system dynamics useful for numerous types of assessments, ranging from the vulnerability of coupled human–environment systems to forest transitions. With antecedents in several research communities, land architecture addresses the tradeoffs within and between the human and environmental subsystems of land systems in terms of the kind, magnitude, and pattern of land uses and covers. This approach is especially cogent for changes in tropical forests, given the broad-ranging forces acting on them and the equally broad-ranging consequences of their loss. The rudiments of the land architecture approach are illustrated for changes in seasonal tropical forests in the southern Yucatán of Mexico, the pivot of which is the Calakmul biosphere reserve. Simplifying the dynamics involved, the region-wide land architecture is the collective design of stakeholders with different land-use goals that favor tradeoffs in subsystem outcomes serving better either the reserve and related programs or the smallholder farmers that populate the region. A major tradeoff involves forest cover per se, which holds implications for forest transition theory. Evidence for an incipient transition involves the scale of analysis taken. The dynamics involved hold too much uncertainty to forecast a permanent transition to more forest cover and imply that more complex but robust versions of the theory are required.  相似文献   
9.
This paper re-examines the stochastic properties of U.S. state real per capita personal income, using new panel unit-root procedures. The new developments incorporate non-linearity, asymmetry, and cross-sectional correlation within panel-data estimation. Including nonlinearity and asymmetry finds that 43 states exhibit stationary real per capita personal income whereas including only nonlinearity produces 42 states that exhibit stationarity. Stated differently, we find that two states exhibit nonstationary real per capita personal income when considering nonlinearity, asymmetry, and cross-sectional dependence.  相似文献   
10.
    
It is important to compare the resilience of complex human systems to different types of disasters, in order to assess their inherent vulnerabilities and take appropriate actions to strengthen them. Resilient behavior can be complicated and multi-dimensional, however, and one must be able to characterize the different ways in which that resilience actually exhibits itself in practice. With this in mind, this paper discusses creating a multi-dimensional indicator for the resilience of a complex human system, and it explores an approach for visualizing and analyzing the relationships between each of the individual resilience dimensions. Because decision makers may differ on the relative contribution of the different dimensions to overall resilience, the paper further discusses the issue of weighting the different dimension values and the impacts that such a weighting scheme can have on the relative ranking of different scenarios. We illustrate the ability to characterize the complexity of multi-dimensional resilience by analyzing an empirical data set that measures the relative resilience of the New York metropolitan area to seven different natural disasters between 2010 and 2012.  相似文献   
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