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2.
This paper presents an algorithm that permits the search for dependencies among sets of data (univariate or multivariate time-series, or cross-sectional observations). The procedure is modeled after genetic theories and Darwinian concepts, such as natural selection and survival of the fittest. It permits the discovery of equations of the data-generating process in symbolic form. The genetic algorithm that is described here uses parts of equations as building blocks to breed ever better formulas. Apart from furnishing a deeper understanding of the dynamics of a process, the method also permits global predictions and forecasts. The algorithm is successfully tested with artificial and with economic time-series and also with cross-sectional data on the performance and salaries of NBA players during the 94–95 season. 相似文献
3.
灰铸铁石墨形态的研究 总被引:3,自引:0,他引:3
文本研究了化学成份与冷却速度及孕育处理对灰铸铁石、墨形态的影响.并对形成的地B、C、D、E、F等六种衣铸铁石墨形态的形成条件作了讨论. 相似文献
4.
Argyris G. Kagiannas Thanassis Didis Dimitris Th. Askounis John Psarras 《国际能源研究杂志》2003,27(2):173-186
The needs that an energy supply system must meet are constantly changing, due to technological, social and political reasons. Effective energy planning is a dynamic process that is repeated periodically and adjusts to changing conditions. Energy decision makers and planners are no longer able to rely on inductive decision making since they have to investigate the effect of various decision parameters and possible future changes. To help in this process, models have been developed where estimates of future load growth, candidate power plants, fuels and other key factors can be introduced, from which the planners can evaluate decision parameters and the available alternatives. The paper presents the different methodologies and practices that are used by 11 energy models for energy demand forecasting, supply side management and generation expansion planning, demand side management and integrated resource planning. The paper concludes to the presentation of a strategic appraisal of the examined energy models appropriate for energy planning in Mozambique. Three models are proposed for conducting demand forecasting, generation expansion planning and demand side management. Copyright © 2002 John Wiley & Sons, Ltd. 相似文献
5.
非方程灰色系统方法在长期水文预报中的应用初探 总被引:1,自引:1,他引:0
基于水文过程的复杂性和影响因子信息收集不完善这一基本事实,本文将流域水文系统视为含有灰元和灰信息的灰色系统,并初步实践了非方程灰色预报方法在长期水文预报中的应用。方法在一定意义上脱离了传统的以方程为中心的预报模式,它既考虑预报因子对预报量的不同影响程度,又不过分强调预报量与预报因子的具体相关函数形式,为长期水文预报提供了一种新思路。文中列出了实例,效果令人满意。 相似文献
6.
Reviews the book, Basic Processes in Reading Visual Word Recognition by Derek Besner and Glyn W. Humphreys (see record 1990-99017-000). While there has been an increase in the amount of work on many different aspects of reading, as Besner and Humphreys point out in the overview to their book, the vast majority of the research on the topic of reading in the past twenty years has been concerned with the processes involved in word recognition. For this reason, Besner and Humphreys have attempted to bring together studies on topics which are both relevant to current debates in the field of word recognition, and which are likely to be important for future developments in the field. They have compiled an edited volume consisting of their overview and eight additional chapters. The editors have attempted to span the continuum of processes involved in word recognition and thus have included chapters which cover topics ranging from the visual analysis of words, to those on the influence of semantic factors on word recognition. The authors of these chapters comprise an impressive list of researchers in the field of word recognition, with the majority of chapters being authored by leading researchers on the topic. Given the stature of the authors and the range of topics covered, in theory this volume should provide a very thorough overview of current theory and research on reading. There is no question that each of the chapters is interesting and important in its own right. However, in practice the volume as a whole fell somewhat short of my expectations. The different tacts taken by different authors has resulted in a very uneven coverage of the current debates in the field. Notwithstanding these criticisms, I am sure that the majority of researchers in this field will consider this volume to be an important contribution. The book would provide a very useful addition to graduate courses in cognitive sciences and as a supplemental text for an undergraduate course on the psychology of reading. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
7.
In this study forecast of Turkey's net electricity energy consumption on sectoral basis until 2020 is explored. Artificial neural networks (ANN) is preferred as forecasting tool. The reasons behind choosing ANN are the ability of ANN to forecast future values of more than one variable at the same time and to model the nonlinear relation in the data structure. Founded forecast results by ANN are compared with official forecasts. 相似文献
8.
刘道杰 《石油工业计算机应用》2007,15(4):32-34,37
模拟退火算法是一种利用统计力学观点求解优化问题全局最优解的方法,是目前解决优化问题的一种比较先进的方法。本文应用模拟退火算法对蒸汽吞吐注采参数进行优化设计,并确定出了6个吞吐周期的最优周期产油量和周期注蒸汽量,较实际周期产油量和实际周期注汽量均有明显增加。将各周期的优化累积产油量和优化累积注汽量画在累积产油量与累积注汽量的双对数坐标中,得出累积注汽量和累积采油量关系曲线(简称注采关系曲线)。将该注采关系曲线外推估算了该井未来周期的累积产油量和累积注汽量,从而达到对蒸汽吞吐井生产能力的预测。 相似文献
9.
Reviews the book, The mind's we: Contextualism in cognitive psychology by Diane Gillespie (1992). In this text the author has both expanded on several of the key insights previously outlined in the critical literature and provided a congenial introductory text for the newcomer; a text to serve as a conceptual bridge between traditional cognitive psychological approaches and their newly emergent contextualist alternatives. As stated in her preface, Gillespie's purpose in preparing this book was to "bring together the work of psychologists who are interested in telling the contextualist story of cognition" and to "reveal and strengthen their insights and perspectives" (p. xiv). Given the philosophical range and theoretical diversity of those interested in telling such a story, the task is certainly a formidable one, but it is nonetheless one that she accomplishes with a commendable degree of elegance. Gillespie clearly articulates the diverse work of a large number of psychological theorists into a coherent and meaningful account that will do much toward imposing order on a field that is, by its very nature, somewhat scattered and contentious. Each of the book's six chapters proceeds carefully through a detailed and representative historical and conceptual analysis of traditional mechanistic approaches to human cognition prior to advancing their contextualist critiques and alternatives. Through a systematic analysis of the manner in which this "contextualist story" has arisen within the mechanistic milieu of traditional scientific psychology, she is able to clarify both the implications and relative merits and liabilities of two, quite often antithetical, conceptualizations of human cognitive phenomena. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
10.
BP网络过拟合问题研究及应用 总被引:2,自引:0,他引:2
通过类比信息传递过程中的一般测不准关系式,研究BP网络出现过拟合现象时,代表网络学习能力的权值改变量与反映网络推广能力的未参与训练的检验样本的辨识误差之间的关系.在该关系式中引入一个过拟合参数P,通过对岷江流域紫坪埔站的流量预报,说明在判断网络是否出现过拟合现象时,计算过拟合参数P是一种有研究意义的参考. 相似文献