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主要描述了一个基于多层数据库访问技术的自定义报表的实现原理.并简要介绍了部分实现方案和处理流程,举例说明了部分技术要点. 相似文献
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A technological revolution based on information technologies is reshaping the nature of society while globalisation has impacted on the location and nature of economic production and ownership. The scope of these changes indicates a transformation that is equal to the extent of the changes associated with the Industrial Revolution. At the beginning of the third millennium, it is possible to anticipate how these transformative changes will impact upon the way societies and people produce, communicate, manage and live. This paper will outline some of the major changes that have occurred, or will be likely to, over the next two decades, with particular attention to the way in which social institutions and social interaction will evolve. It will also pose questions about the implications for facets of refrigeration given the fundamentally different ways in which societies and individuals will interact with, and expect to use, various technologies. 相似文献
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FAUSTO GIUNCHIGLIA 《人工智能实验与理论杂志》2013,25(2):173-190
Generality and locality have been proposed as two crucial properties for systems formalizing common-sense reasoning. The first is the ability of representing knowledge in a way that makes it usable in a wide class of circumstances. The second is the ability of using only a subset of the potentially available knowledge, namely the subset which is held to be relevant in a given circumstance. These two properties seem to be one the opposite of the other, since disregarding part of the available information (locality) may lead to a loss of generality. In this paper, we argue that this is not the case, and propose a general methodology for combining generality and locality. This methodology is essentially based on the notion of context. As a case study, we propose a formalization of the Glasgow-London-Moscow example and its mechanization in an interactive theorem prover, GETFOL. 相似文献
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To develop a model for biomass gasification in fluidized bed gasifiers with high accuracy and generality that could be used under various operating conditions, the equilibrium model (EM) is chosen as a general and case-independent modeling method. However, EM lacks sufficient accuracy in predicting the content (volume fraction) of four major components (H2, CO, CO2 and CH4) in product gas. In this paper, three approaches—MODEL I, which restricts equilibrium to a specific temperature (QET method); MODEL II, which uses empirical correlations for carbon, CH4, C2H2, C2H4, C2H6 and NH3 conversion; and MODEL III, which includes kinetic and hydrodynamic equations—have been studied and compared to map the barriers and complexities involved in developing an accurate and generic model for the gasification of biomass.This study indicates that existing empirical correlations can be further improved by considering more experimental data. The updated model features better accuracy in the prediction of product gas composition in a larger range of operating conditions. Additionally, combining the QET method with a kinetic and hydrodynamic approach results in a model that features less overall error than the original model based on a kinetic and hydrodynamic approach. 相似文献
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Calibration strategy will influence the calibration performance of three-axis magnetometers. In this paper, three different calibration strategies (symmetrical calibration, orthogonal calibration and random calibration) are introduced and verified by simulation and experiments. The experimental system mainly consists of three-axis fluxgate magnetometer (MAG3300), 2D nonmagnetic rotation equipment and proton magnetometer. The scalar value of magnetic field was obtained with proton magnetometer and considered to be the true value. Calibration performance of three different calibration strategies were analyzed and compared. Experimental results show that after calibration the scalar RMS error has dropped 88.5%, 85.5% and 87.6% respectively. To check the generality of the estimated error parameters, another site was chosen to be a validation position, and the calibration performance of three calibration strategies were tested and compared. After calibration, the scalar RMS error has dropped 83.2%, 78.9% and 78.8% respectively. Thus the symmetrical calibration is considered to be the best calibration strategy among three calibration strategies. 相似文献
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在基于负相关的神经网络群学习算法中,相关项由目标输出或网络群输出定义。本文首先证明无论相关项采用何种定义形式,个体网络的目标函数都等价于网络自身性能和群性能的线性组合,线性组合系数由给定参数和网络群规模共同确定。然后给出个体网络目标函数的统一定义,并分析了目标函数内参数的含义。该目标函数表明负相关算法实际是实现多目标优化,所以网络群算法无需负相关概念,从而在概念和实现两方面简化了负相关算法。 相似文献