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121.
Neural tree model has been successfully applied to solving a variety of interesting problems. In most previous studies, optimization of the neural tree model was divided into two steps: first structure optimization, then parameter optimization. One major problem in the evolution of structure without parameter information was noisy fitness evaluation. In this paper, an improved breeder genetic programming algorithm is proposed to the synthesis of neural tree model. The effectiveness and performance of the method are evaluated on time series prediction problems and compared with those of related methods. Simulation results show that the proposed algorithm is a potential method with better performance and effectiveness.  相似文献   
122.
OpenGL被认为是高性能图形和交互式视景处理的标准,可以制作出顺畅的3D效果,且性能也是非常出色的。所以在当今的三维绘制领域,其占据了不可动摇的位置。我国的三维创作发展起步相当晚,必须努力钻研迎头赶上。  相似文献   
123.
建立RP-HPLC法测定多维片中维生素B1(VB1)、维生素B2(VB2)、维生素B6(VB6)、维生素C(VC)和烟酰胺5种主药的含量.色谱柱为安捷伦的C18柱,以甲醇-乙腈-缓冲盐(体积比为11:11:78)为流动相,检测波长210nm,流速1.0mL/min,测定多维片中主药的含量.结果显示各组分和辅料能够达到完全分离,分离度均大于2.0;VB1,VB2,VB6,VC和烟酰胺在质量浓度范围内具有良好的线性关系,r均能达到0.999,平均回收率分别为98.8%,99.5%,99.1%,99.2%和99.9%(n=9),RSD均小于2.0%.可见用所建立的分析方法测定多维片中5种主药的含量,结果准确、可靠,能够有效控制产品质量.  相似文献   
124.
利用激光拉曼光谱、红外吸收光谱并结合宝石学特征对山东昌乐某蓝宝石砂矿中的锆石谱学特征和变生程度进行了研究.拉曼图谱显示,锆石的变生系数H/W值(1007 cm-1)大都大于600(在625~5412,仅1个为441),主要为全晶质锆石和弱变生锆石,变生程度很小.红外光谱的结果表明,锆石的结晶程度高度一致,H/M值(610 cm-1):原样为20~23,氧化条件热处理(600℃)后为20~22,还原条件热处理(600℃)后为28~30,判断为晶质锆石;样品的物理性质与晶质锆石比较接近.因此,所测样品为变生程度很弱的高型锆石,还原条件下热处理后锆石的变生系数有明显增大,其结晶度有所改善.  相似文献   
125.
An accurate closed form solution is proposed to estimate camera pose by several mirrored reference object images acquired via a planar mirror under different unknown poses. Compared with state-of-the-art methods, our method is more accurate when there are more than three images and has explicit geometric meanings. This method also properly handles cases in which some of the mirror poses are parallel. The central idea is to minimize an error metric based on all reflections of rotation, which enables the camera rotation to be estimated directly by SVD of sum of mirrored camera rotations. After that, the camera translation is computed by solving a large system of linear equations to minimize object space collinearity error. Both synthesized data and real data experiments show the advantages of our approach.  相似文献   
126.
针对ESO参数不易整定的问题,研究了扩张状态观测器(ESO)参数优化的李雅普诺夫函数法.首先建立关于误差的线性定常状态方程和误差指标函数J,在误差指标函数J中综合考虑了跟踪误差的权重和系统的稳定性以及实际运行时的饱和值限制等因素.仿真结果表明,此方法具有概念清晰,实用简便,计算量小的优点.所提ESO参数整定方法是有效的.  相似文献   
127.
This paper develops a new quantitative model to find the optimal number of new employees with a Newsvendor model in a pull production system. This model allows learning, forgetting and variable wage. This paper also provides numerical results on sensitivity analysis, and compares the numerical results in three different situations: the situation with both learning and forgetting effect, that with learning effect but without forgetting effect and the situation with neither learning nor forgetting effect. The conclusions drawn from the comparison may offer theoretical insight for human resource managers to make appropriate employment decisions.  相似文献   
128.
Ant colony optimization (ACO) is a metaheuristic approach for combinatorial optimization problems. With the introduction of hypercube framework, invariance property of ACO algorithms draws more attention. In this paper, we propose a novel two-stage updating pheromone for invariant ant colony optimization (TSIACO) algorithm. Compared with standard ACO algorithms, TSIACO algorithm uses solution order other than solution itself as independent variable for quality function. In addition, the pheromone trail is updated with two stages: in one stage, the first r iterative optimal solutions are employed to enhance search capability, and in another stage, only optimal solution is used to accelerate the speed of convergence. And besides, the pheromone value is limited to an interval. We prove that TSIACO not only has the property of linear transformational invariance but also has translational invariance. We also prove that the pheromone trail can limit to the interval (0, 1]. Computational results on the traveling salesman problem show the effectiveness of TSIACO algorithm.  相似文献   
129.
This paper describes the Si-doping of GaAs that was grown using the AsCl3:H2:GaAs, Ga Chemical vapor deposition process. The doping sources were AsCl3:SiCl4 liquid solutions which proved to be highly reproducible for Si doping within the range, 1×1O16 to 2×1019 cm?3. Incorporation of Si into the GaAs apparently occurs under near equilibrium conditions. This point is considered in detail and the consequences experimentally utilized to grow n, n+ bilayers using a single AsCl3:SiCl4 doping solution. Si impurity profiles based upon differential capacitance and SIMS data are presented. These can be very abrupt for n, n+ structures with order of magnitude changes occurring within 500 Å. For the 1×1016 to 8×l018 cm?3 doped samples the mobilities at 78 and 298°K are comparable to the higher values reported for GaAs thin films grown by CVD. Power FET devices made from this material have demonstrated an output density of 0.86 watts/mm at 10 GHz.  相似文献   
130.
通过对石墨化炉的特点及其供电方面的有关问题的分析,论述了石墨化炉供电的特点及其发展的趋势,并对石墨化炉在交、直流电源供电方面提出了看法,以不断提高石墨化炉供电的设计水平.  相似文献   
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