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1.
提出了求解长期最优控制问题的一种新方法——启发式预估方法。该方法的主要特点是在每个子问题中引进一个启发项,并且在协调级采用了预估算法.对于严格凸问题,可以证明分解问题与原问题是等价的.同时还给出了该方法的一种并行算法.与P.B.Luh方法相比,启发式预估方法不仅能简化协调级的计算,而且能减少协调级的迭代次数,从而显著提高了问题的求解速度.仿真结果表明该方法是可行的,并且在实时控制中具有广阔的应用前景。  相似文献   

2.
背包问题是一个具有较强应用价值的NP完全问题.如何设计求解此类问题的算法,则具有很强的实用价值和理论意义.目前已有很多的求解方法,但背包问题并没有完全解决.本文在启发式算法的理论基础上,改进了进化规划算法求解背包问题,此方法简单通用、易于操作.数值实验表明该方法具有较高的准确率,能较快的收敛到全局最优点.  相似文献   

3.
一种基于伏格尔法的指派问题新算法   总被引:1,自引:0,他引:1  
指派问题是一个应用广泛的运筹学问题.用伏格尔(Vogel)法以及闭合回路验优和调优的方法给出了指派问题的新算法,该算法避免了匈牙利法可能导致死循环的缺陷.并编制了通用高效的计算机程序,该程序能求解任意n人员n任务的指派问题.  相似文献   

4.
求解非线性方程组的非单调自适应信赖域方法   总被引:1,自引:0,他引:1  
提出了一个新的求解非线性方程组的信赖域方法,首先把非线性方程组的求解转化成一个非线性优化问题,然后借助非单调技术和信赖域技术求解该问题,从而得到了原方程组的解.既避免了重复求解信赖域子问题,又减少了线搜索方法计算函数值的次数.算法的收敛性得到了证明,初步的数值试验表明了算法的有效性.  相似文献   

5.
景元萍  张永胜 《河南科学》2012,30(5):552-555
对于具有初始条件的线性非自治系统,给出了一种新的数值解法.该方法把所求初值问题转化成线性规划问题,通过求解线性规划问题得到原问题的一个近似解.定量误差分析和实际算例表明,该方法可以有效地求解线性非自治系统初值问题的近似解,也适用于边值问题的近似求解.  相似文献   

6.
针对机构综合的非线性方程组求解问题提出了一种混合混沌算法,将方程组转换成一个优化问题,然后利用优化问题的非线性共轭梯度法与混沌优化方法相结合进行优化求解,该算法能使非线性共轭梯度法跳出局部最优,最终获得全局最优.机构综合实例表明:笔者提出的方法能够求出非线性方程组的所有实数解,算法有效、简单、实用.  相似文献   

7.
王训遒  王秋丽 《太原科技》2008,168(1):70-71
为了解决<化工原理>传热学习中操作型计算难以掌握的问题,介绍了运用对比法求解换热器操作型问题的原理,并通过两道例题详细说明了该方法的求解过程,该方法解题过程清晰.并且能普遍运用.  相似文献   

8.
根据重现期P-降雨历时t-暴雨强度i的关系表,推求暴雨强度公式参数,是一个已知关系式的非线性模型参数优化求解问题.在理论分析及前人研究的基础上,把求解无约束最优化问题的交尺度DFP算法嵌入到改进浮点编码遗传算法中,得到一种基于变尺度DFP算法和改进浮点编码遗传算法的加速混合遗传算法.该方法兼顾了改进浮点编码遗传算法和DFP算法的优点,既有较快速的收敛速度,又能求得最优化问题全局精确解.经求解暴雨强度公式参数的实例表明,该法是有效的和可行的,且求解结果优于其它方法.  相似文献   

9.
针对一类状态矩阵和输入矩阵中存在数值界不确定性的时滞关联大系统,研究其分散鲁棒输出反馈控制器设计问题.基于一个时滞依赖有界实引理,将系统鲁棒分散H∞动态输出反馈控制器的解归结为一个非线性矩阵不等式的求解问题;选取适当的同伦函数来表示该非线性矩阵不等式,采用同伦迭代算法及Schur补引理,将求解非线性矩阵不等式转化为线性矩阵不等式的迭代求解问题.所得的控制器能使闭环大系统鲁棒稳定,并满足给定的H∞性能指标.仿真算例验证了该方法的有效性.  相似文献   

10.
采用多智能体系统求解方法, 将异构资源分配问题建模于分布式广义分配问题框架下, 利用智能体间的联合搜索实现复杂异构资源分配问题的高效求解. 先利用前期搜索过程中获得的知识, 智能体预测谁更有能力求解当前子问题; 再通过建立决策模型, 智能体动态、 智能地改变搜索顺序, 以加速全局可行解的求解. 该非集中式框架能提高问题的求解效率, 增加动态可扩展性. 实验结果表明了该方法的可行性.  相似文献   

11.
Language markedness is a common phenomenon in languages, and is reflected from hearing, vision and sense, i.e. the variation in the three aspects such as phonology, morphology and semantics. This paper focuses on the interpretation of markedness in language use following the three perspectives, i.e. pragmatic interpretation, psychological interpretation and cognitive interpretation, with an aim to define the function of markedness.  相似文献   

12.
The discovery of the prolific Ordovician Red River reservoirs in 1995 in southeastern Saskatchewan was the catalyst for extensive exploration activity which resulted in the discovery of more than 15 new Red River pools. The best yields of Red River production to date have been from dolomite reservoirs. Understanding the processes of dolomitization is, therefore, crucial for the prediction of the connectivity, spatial distribution and heterogeneity of dolomite reservoirs.The Red River reservoirs in the Midale area consist of 3~4 thin dolomitized zones, with a total thickness of about 20 m, which occur at the top of the Yeoman Formation. Two types of replacement dolomite were recognized in the Red River reservoir: dolomitized burrow infills and dolomitized host matrix. The spatial distribution of dolomite suggests that burrowing organisms played an important role in facilitating the fluid flow in the backfilled sediments. This resulted in penecontemporaneous dolomitization of burrow infills by normal seawater. The dolomite in the host matrix is interpreted as having occurred at shallow burial by evaporitic seawater during precipitation of Lake Almar anhydrite that immediately overlies the Yeoman Formation. However, the low δ18O values of dolomited burrow infills (-5.9‰~ -7.8‰, PDB) and matrix dolomites (-6.6‰~ -8.1‰, avg. -7.4‰ PDB) compared to the estimated values for the late Ordovician marine dolomite could be attributed to modification and alteration of dolomite at higher temperatures during deeper burial, which could also be responsible for its 87Sr/86Sr ratios (0.7084~0.7088) that are higher than suggested for the late Ordovician seawaters (0.7078~0.7080). The trace amounts of saddle dolomite cement in the Red River carbonates are probably related to "cannibalization" of earlier replacement dolomite during the chemical compaction.  相似文献   

13.
何延凌 《科技信息》2008,(4):258-258
Language is a means of verbal communication. People use language to communicate with each other. In the society, no two speakers are exactly alike in the way of speaking. Some differences are due to age, gender, statue and personality. Above all, gender is one of the obvious reasons. The writer of this paper tries to describe the features of women's language from these perspectives: pronunciation, intonation, diction, subjects, grammar and discourse. From the discussion of the features of women's language, more attention should be paid to language use in social context. What's more, the linguistic phenomena in a speaking community can be understood more thoroughly.  相似文献   

14.
AcomputergeneratorforrandomlylayeredstructuresYUJia shun1,2,HEZhen hua2(1.TheInstituteofGeologicalandNuclearSciences,NewZealand;2.StateKeyLaboratoryofOilandGasReservoirGeologyandExploitation,ChengduUniversityofTechnology,China)Abstract:Analgorithmisintrod…  相似文献   

15.
理论推导与室内实验相结合,建立了低渗透非均质砂岩油藏启动压力梯度确定方法。首先借助油藏流场与电场相似的原理,推导了非均质砂岩油藏启动压力梯度计算公式。其次基于稳定流实验方法,建立了非均质砂岩油藏启动压力梯度测试方法。结果表明:低渗透非均质砂岩油藏的启动压力梯度确定遵循两个等效原则。平面非均质油藏的启动压力梯度等于各级渗透率段的启动压力梯度关于长度的加权平均;纵向非均质油藏的启动压力梯度等于各渗透率层的启动压力梯度关于渗透率与渗流面积乘积的加权平均。研究成果可用于有效指导低渗透非均质砂岩油藏的合理井距确定,促进该类油藏的高效开发。  相似文献   

16.
As an American modern novelist who were famous in the literary world, Hemingway was not a person who always followed the trend but a sharp observer. At the same time, he was a tragedy maestro, he paid great attention on existence, fate and end-result. The dramatis personae's tragedy of his works was an extreme limit by all means tragedy on the meaning of fearless challenge that failed. The beauty of tragedy was not produced on the destruction of life, but now this kind of value was in the impact activity. They performed for the reader about the tragedy on challenging for the limit and the death.  相似文献   

17.
本文叙述了对海南岛及其毗邻大陆边缘白垩纪到第四纪地层岩石进行古地磁研究的全部工作过程。通过分析岩石中剩余磁矢量的磁偏角及磁倾角的变化,提出海南岛白垩纪以来经历的构造演化模式如下:早期伴随顺时针旋转而向南迁移,后期伴随逆时针转动并向北运移。联系该地区及邻区的地质、地球物理资料,对海南岛上述的构造地体运动提出以下认识:北部湾内早期有一拉张作用,主要是该作用使湾内地壳显著伸长减薄,形成北部湾盆地。从而导致了海南岛的早期构造运动,而海南岛后期的构造运动则主要是受南海海底扩张的影响。海南地体运动规律的阐明对于了解北部湾油气盆地的形成演化有重要的理论和实际意义。  相似文献   

18.
There are numerous geometric objects stored in the spatial databases. An importance function in a spatial database is that users can browse the geometric objects as a map efficiently. Thus the spatial database should display the geometric objects users concern about swiftly onto the display window. This process includes two operations:retrieve data from database and then draw them onto screen. Accordingly, to improve the efficiency, we should try to reduce time of both retrieving object and displaying them. The former can be achieved with the aid of spatial index such as R-tree, the latter require to simplify the objects. Simplification means that objects are shown with sufficient but not with unnecessary detail which depend on the scale of browse. So the major problem is how to retrieve data at different detail level efficiently. This paper introduces the implementation of a multi-scale index in the spatial database SISP (Spatial Information Shared Platform) which is generalized from R-tree. The difference between the generalization and the R-tree lies on two facets: One is that every node and geometric object in the generalization is assigned with a importance value which denote the importance of them, and every vertex in the objects are assigned with a importance value,too. The importance value can be use to decide which data should be retrieve from disk in a query. The other difference is that geometric objects in the generalization are divided into one or more sub-blocks, and vertexes are total ordered by their importance value. With the help of the generalized R-tree, one can easily retrieve data at different detail levels.Some experiments are performed on real-life data to evaluate the performance of solutions that separately use normal spatial index and multi-scale spatial index. The results show that the solution using multi-scale index in SISP is satisfying.  相似文献   

19.
20.
The elongation method,originally proposed by Imamura was further developed for many years in our group.As a method towards O(N)with high efficiency and high accuracy for any dimensional systems.This treatment designed for one-dimensional(ID)polymers is now available for three-dimensional(3D)systems,but geometry optimization is now possible only for 1D-systems.As an approach toward post-Hartree-Fock,it was also extended to  相似文献   

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