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51.
Using the CALPHAD (Calculation of Phase Diagram) technique, the DyCl3-MCl (M = Na, K, Rb, Cs) systems were optimized and calculated. The modified quasi-chemical model in the pair approximation for short-range ordering was used to describe the Gibbs energies of the liquid phase in these systems. From the measured phase diagram data and experimental thermodynamic properties, a series of thermodynamic functions were optimized base on an interactive computer-assisted analysis. The optimized parameters and the experimental data were thermodynamically self-consistent. The optimized results were discussed. 相似文献
52.
Abstract. Niche companies are per definition idiosyncratic. They survive in a competitive world by mastering a small market niche, providing what their customers need. This often requires a flexible organization, and the ability to customize products. To be more efficient, many of these companies rely on extensive use of IT, often by installing general Enterprise Resource Planning (ERP) systems. These systems have grown from isolated systems that handle planning based on incoming orders and the component structure of the various products, to systems with ambitions to embrace the total functioning of the company including vendor and customer relation management. In this paper, we present four case studies. One company is a part of a large enterprise, but performs niche functions within this enterprise. The other three are small- or medium-sized enterprises. Each of these performs in small niche markets. Common to all is the fact that they encounter problems with the utilization of their ERP systems. The major problem seems to be that the ERP system has an inherent business model that may not conform to the needs of the company. Without a good understanding of the underlying models and the constraints under which the fundamental algorithms operate, it is difficult to use these systems correctly. Even excellent systems may give bad results if they are applied to situations where they are not suited. Further, the monolithic structure of an ERP system, with a rather complicated parameter setting, is often insufficient to mould the system to the needs of a niche company. We discuss these problems based on our four case studies, and offer alternative approaches that may be considered. 相似文献
53.
Jean-Baptiste Lesourd 《Energy Economics》1985,7(3):138-144
It is shown that, when the mean productivity of some factors, such as energy or materials, is upperly bounded (a condition usually arising in energy production or in the process industries where energy takes part in physico-chemical processes), the production function may not be convex and, under some further conditions, is concave. Consequences of this model on the economics of energy savings are examined, and it is shown that energy savings may be considered at three levels: in the short run, by action on labour factors: in the medium run, by investment and action on labour factors; in the long run, by technological innovation, investment in new technologies and action on labour factors. Empirical findings along these lines are thus confirmed. 相似文献
54.
Since Samuel's work on checkers over thirty years ago, much effort has been devoted to learning evaluation functions. However, all such methods are sensitive to the feature set chosen to represent the examples. If the features do not capture aspects of the examples significant for problem solving, the learned evaluation function may be inaccurate or inconsistent. Typically, good feature sets are carefully handcrafted and a great deal of time and effort goes into refining and tuning them. This paper presents an automatic knowledge-based method for generating features for evaluation functions. The feature set is developed iteratively: features are generated, then evaluated, and this information is used to develop new features in turn. Both the contribution of a feature and its computational expense are considered in determining whether and how to develop it further.
This method has been applied to two problem-solving domains: the Othello board game and the domain of telecommunications network management. Empirical results show that the method is able to generate many known features and several novel features and to improve concept accuracy in both domains. 相似文献
This method has been applied to two problem-solving domains: the Othello board game and the domain of telecommunications network management. Empirical results show that the method is able to generate many known features and several novel features and to improve concept accuracy in both domains. 相似文献
55.
针对传统分步式结构优化设计的不足,提出一种同时进行结构拓扑、形状和尺寸统一优化的设计方法.首先采用水平集函数描述统一的结构优化模型和几何尺寸边界,通过引入紧支径向插值基函数将结构拓扑优化变量、形状优化变量和尺寸优化变量变换为基函数的扩展系数;然后取该扩展系数为设计变量,借助一种参数的变化表达3种优化要素对结构性能的影响,将复杂的多变量优化问题变换为相对简单的参数优化问题,有利于与相对成熟的优化算法相结合提高求解效率;进一步用R函数将其融合为一个整体,构造出统一优化模型,并用最优化准则法进行求解.最后通过数值案例证明了该方法的有效性和精确性. 相似文献
56.
为了实现5G网络场景下服务功能链的低成本高效率部署,提出了一种基于改进麻雀搜索算法的服务功能链优化映射算法。在服务功能链映射过程中,采用双层编码方式,将服务请求的组链方案和映射方案进行混合编码,然后使用改进离散麻雀搜索算法进行求解,得到该请求的服务功能链部署方案,并计算其映射权重。当同一时间片内存在多个请求类型时,按照映射权重对所有服务功能链进行排序,优先映射权重高的请求,以此减少延迟开销,提高节点计算资源利用率和链路资源利用率。仿真结果表明,该算法可以有效减少部署开销,提高资源利用率。 相似文献
57.
主要介绍了装卸机械控制系统的构成、系统在运行过程中的控制要求、以及如何实现机械自动操作的功能,利用S7-300PLC的功能模块化程序设计思想,设计出手动控制逻辑功能和自动控制逻辑功能及组织块程序,大大提高了工作效率和生产安全性。 相似文献
58.
For pseudo-random generators where one or several LFSRs are combined by a memoryless function, it is known that the output sequences are correlated to certain LFSR-sequences whose correlation coefficients c
t
satisfy the equation
i
c
2
i
= 1. In this paper it is proved that a corresponding result also holds for generators whose LFSRs are connected to a combiner with memory.If correlation probabilities are conditioned on side information, e.g., on known output digits, it is shown that new or stronger correlations may occur. This is exemplified for the summation cipher with only two LFSRs where such correlations can be exploited in a known plaintext attack. A cryptanalytic algorithm is given which is shown to be successful for LFSRs of considerable length and with arbitrary feedback connection.A preliminary version of this paper was presented at Eurocrypt '90, May 21–24, Århus, Denmark, and has appeared in the proceedings, pp. 204–213. 相似文献
59.
提出一种新的基于全局图像信息和局部图像特征的活动轮廓分割模型。模型的总能量函数主要包括3项:全局能量项、局部能量项和自适应调节项。其中,全局能量项整合了图像的全局信息,局部能量项则考虑了图像的局部特征,而二者的权重会根据上下文内容自适应调整。由于在模型中充分利用了图像全局信息和局部特征,因而有效地提高了分割的精度。此外,加入了凸优化技术,以获取模型的全局最优解。最后,采用Split-Bregman方法进行快速求解,使得模型的分割效率大大提高。实验结果表明,该模型对初始化具有较好的鲁棒性,在分割精度上有了较大的提升,特别是分割速度比C-V模型快1.5倍到2倍。 相似文献
60.
本文以二次Bernstein基函数为例,首次提出了含双参数基函数的新扩展——αβQ—Bern-stein基函数,此类基函数具有新的特点,即基函数的扩展次数一次性升高两次,且包含了二次多项式和带一个参数的三次多项式基函数的所有性质。基于这组基函数定义了αβQ—Bézier曲线,该曲线也含有参数,具有形状可调性,当α与β取某些值时曲线能达到C4连续或在某个端点处C0连续。最后与含两个参数的升一次Bézier曲线进行比较,该曲线具有调节范围广、灵活性更强的优势。 相似文献