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1.
基于满意度原理的多学科协同优化   总被引:3,自引:0,他引:3  
由于多学科设计优化涉及众多复杂因素,各个学科需要满足的约束是不同的,而系统级通常采用一致性约束来保证学科级共享、耦合变量及目标值的一致,在很多情况下共享、耦合变量及目标值满足了约束,但是各个学科获得的并不是本学科的最优解.本文采用满意度原理设计协同优化的系统级目标函数,综合考虑了学科级优化解的满意度和共享、耦合变量及目标值对于一致性约束的满意度,以增强协同优化的综合处理能力.齿轮变速箱优化实例表明该方法是可行有效的.  相似文献   

2.
针对协同优化的系统级优化可行域可能不存在的问题,采用遗传算法,并借鉴逐步增强约束强度的思想,提出了基于遗传算法的协同优化算法.该算法利用各子学科返回的优化值,计算种群中个体的不可行度,根据不可行度和阈值来判定该个体是否为可行解.提出利用循环迭代次数调整阈值的方法,保证了系统级优化向一致性等式约束不满足度减小的方向进行,达到了有效增强子学科间一致性的目的.最后,利用减速器典型算例对该方法进行了验证,结果表明该方法的优化性能良好.  相似文献   

3.
混合变量多目标优化设计的Pareto遗传算法实现   总被引:12,自引:0,他引:12  
提出了一种用Pareto遗传算法来实施的带约束的多目标混合变量的优化方法。得到Pareto最优解集,决策者从中可选出满足设计需要的解。该算法包括6个基本算子:选择、变异、交叉、离散变量圆整算子、小生境、Pareto集合过滤器。建立了用于多目标优化的适应度函数,使用模糊罚函数法法将带约束的多目标优化问题转换为无约束优化问题,同时提出了处理混合变量多目标优化问题中离散变量的方法。最后用算例说明了该方法  相似文献   

4.
传统软子空间聚类算法在利用局部搜索策略解决等式约束的连续非线性的变量加权问题时,易陷入局部最优导致聚类效果不佳.针对该问题,该文提出了一种随机学习萤火虫算法优化的模糊软子空间聚类算法.该算法利用具有全局搜索能力的萤火虫算法对新算法的目标函数进行优化,同时,为弥补萤火虫算法易提前收敛和寻优精度较低的缺陷,对萤火虫种群进化...  相似文献   

5.
针对单管感应电能传输系统参数优化中存在的设计参数约束少、参数非全局最优等问题,提出一种参数全局优化算法。将系统效率最高作为目标函数,以原副边电感、电容等关键器件的电压、电流大小为约束条件,将工作频率、原副边电感、电容作为优化变量,建立系统的非线性规划数学模型,采用智能优化算法进行模型解算。为避免算法收敛于局部最优,设计了"遗传算法+模式搜索"的混合算法,即在遗传算法求得最优解的基础上,采用模式搜索进行深度优化。仿真和实验结果表明,提出的方法能从全局角度对系统进行整体优化,单次优化得到所有最优参数,减少了工作量;求解时的混合优化算法具有较优的全局搜索能力,可用于其他约束优化问题。  相似文献   

6.
针对一类特殊的非凸非光滑约束优化问题提出了邻近滤子束算法.该问题的目标函数为lower-c2而约束函数为凸的.具体地,首先对目标函数采用凸化技术得到修正的问题,接着利用改进函数将修正后的约束问题转变为无约束问题,设计邻近束算法来求解这个无约束问题并在邻近束算法中引入滤子策略来确定下降步.数值结果表明了该算法的有效性和可...  相似文献   

7.
结合变换函数方法和下降算法对目标函数有多个极值点且带有线性约束的非线性规划全局问题提出算法.使用的变换函数兼具填充函数和打洞函数的特点.在理论上证明如果当前局部极小点不是全局最优解,一定存在一个变换函数的极小点使得该点的目标函数值小于当前局部极小点的函数值,且该点位于原问题的可行域内.以此点为初始点求解原问题可得到更好的局部极小点.  相似文献   

8.
对一类带不等式约束的二次规划反问题的求解方法进行研究。首先表示出此类二次规划对应的反问题形式,将该反问题转化为目标函数变量可分离优化问题,将其中约束写成KKT条件的形式之后,该反问题等同于一个等式约束优化问题。综合以上,考虑使用交替方向乘子法进行迭代,在此基础之上,将同伦思想应用于算法每步迭代的子问题中,以此避免近端算子选取的敏感性,又可保证算法的收敛速度。针对子问题,使用逐次超松弛法进行求解,并获取算法的收敛性。最后,将该算法与SDPT3和Sedumi两种方法进行比较,数值结果表明,该算法无论在速度上还是效率上都优于以上两种方法。  相似文献   

9.
针对传统进化算法求解多目标优化问题时存在计算量大、难以平衡收敛速度和种群分布均匀性的问题,本文提出了一种基于区域失衡子空间的领先NSGAII算法(NSGAII-URS).首先,基于NSGAII算法,结合局部搜索算法,在每次遗传过程中添加种群领先解解集,引导种群快速收敛;然后,将非支配解所在的目标空间均匀划分,提出稀疏子空间和空闲子空间的概念,通过基于稀疏度的局部搜索策略对失衡子空间优化,进一步提升种群分布的均匀性.我们将本文方法与其他5种先进的多目标进化算法比较,通过基准测试函数进行验证,并采用反世代距离(IGD)和超体积(HV)两个通用指标进行性能评价.实验结果表明,该算法在解的分布性和收敛性方面明显优于对比的其他多目标优化算法.  相似文献   

10.
本文分析了协同优化算法中所存在的问题,采用动态罚函数的解决思路,对系统级中的一致性等式约束问题进行改造,使其成为一无约束问题.另外,提出不同学科分配不同的惩罚权重的方法,大大提高了计算精度.同时,以粒子群算法替代了原有的求解算法,消除了初始解对优化结果的影响,也改善了算法的整体求解速度.在Matlab软件中实现该算法的运行,同时通过两个典型算例对该算法进行验证,表明其具有较好的优化性能.  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.
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   

13.
王慧 《科技信息》2008,(10):240-240
Wuthering Heights, Emily Bronte's only novel, was published in December of 1847 under the pseudonym Ellis Bell. The book did not gain immediate success, but it is now thought one of the finest novels in the English language. Catherine is the key character of this masterpiece, because everybody and everything center on her though she had a short life. We can understand this masterpiece better if we know Catherine well.  相似文献   

14.
The Williston Basin is a significant petroleum province, containing oil production zones that include the Middle Cambrian to Lower Ordovician, Upper Ordovician, Middle Devonian, Upper Devonian and Mississippian and within the Jurassic and Cretaceous. The oils of the Williston Basin exhibit a wide range of geochemical characteristics defined as "oil families", although the geochemical signature of the Cambrian Deadwood Formation and Lower Ordovician Winnipeg reservoired oils does not match any "oil family". Despite their close stratigraphic proximity, it is evident that the oils of the Lower Palaeozoic within the Williston Basin are distinct. This suggests the presence of a new "oil family" within the Williston Basin. Diagnostic geochemical signatures occur in the gasoline range chromatograms, within saturate fraction gas chromatograms and biomarker fingerprints. However, some of the established criteria and cross-plots that are currently used to segregate oils into distinct genetic families within the basin do not always meet with success, particularly when applied to the Lower Palaeozoic oils of the Deadwood and Winnipeg Formation.  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.
Location based services is promising due to its novel working style and contents.A software platform is proposed to provide application programs of typical location based services and support new applications developing efficiently. The analysis shows that this scheme is easy implemented, low cost and adapt to all kinds of mobile nework system.  相似文献   

18.
以AC-13级配为基础,将橡胶颗粒代替部分集料掺入混合料中,以低温弯曲试验为评价方法对不同橡胶颗粒掺量下沥青混合料的低温抗裂性进行研究,并引入应变能密度值对混合料的低温抗裂性进行综合评价.试验结果表明:橡胶颗粒沥青混合料试件的破坏微应变均超过2 300,满足冬寒区的技术指标;无论是否掺加橡胶颗粒,随着温度的下降,沥青混合料破坏时的最大弯拉强度增大,弯拉应变降低,劲度模量增大;弯曲应变能密度在胶粒掺量为1%左右时具有较大的弯曲应变能密度值,此时橡胶颗粒沥青混合料具有较好的低温抗裂性.  相似文献   

19.
正The periodicity of the elements and the non-reactivity of the inner-shell electrons are two related principles of chemistry,rooted in the atomic shell structure.Within compounds,Group I elements,for example,invariably assume the+1 oxidation state,and their chemical properties differ completely from those of the p-block elements.These general rules govern our understanding of chemical structures and reactions.Using first principles calcula-  相似文献   

20.
We have developed an adiabatic connection to formulate the ground-state exchange-correlation energy in terms of pairing matrix linear fluctuations.This formulation of the exchange-correlation energy opens a new channel for density functional approximations based on the many-body perturbation theory.We illustrate the potential of such approaches with an approximation based on the particle-particle Random Phase Approximation(pp-RPA).This re-  相似文献   

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