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1.
以生命线工程网络系统造价为优化目标,网络拓扑结构为优化参数,网络节点抗震连通可靠度为约束条件,建立生命线工程网络系统的抗震拓扑优化模型.同时,介绍了利用递推分解算法来获得单元重要度的方法,进而利用遗传算法、模拟退火算法和遗传-模拟退火混合算法,进行了生命线网络系统的抗震拓扑优化分析.其中,遗传算法通过对种群选择、交叉和变异操作不断进化以获得优化解,模拟退火算法则通过扰动当前解产生新解来获得优化解,遗传-模拟退火混合算法则通过将遗传算法中的变异操作以模拟退火操作代替获得优化解.利用三种优化方法对两个算例进行生命线工程网络系统的抗震拓扑优化分析.计算结果对比表明,遗传-模拟退火混合算法具有最好的优化能力.  相似文献   

2.
基于自适应退火遗传算法的船舶管路布局优化方法   总被引:1,自引:1,他引:0  
采用自适应遗传算法来确定标准遗传算法的杂交率和变异率,尤其对变异率的调整,使其不但能根据个体适应值的大小进行自适应修正,而且能随进化状态的改变而改变,从而增强了算法摆脱局部最优解的能力.同时引入模拟退火思想,通过对标准遗传算法接受算子的退火处理,使其在搜索过程中除了接受优化解以外还以Metropolis准则接受恶化解,提高了种群的多样性,有效地增强了全局寻优能力.通过对适应值函数的退火拉伸,调整了进化前后期的适应值差异,从而加速了寻优过程.最终以形成的自适应模拟退火遗传算法进行船舶管路的三维布局优化,仿真实验表明,该算法不但加快了寻优速度,而且与标准遗传算法相比全局收敛率提高了近30%.  相似文献   

3.
配电网分段开关优化配置,可以减少用户停电损失,提高供电可靠性。分段开关优化配置是一种以可靠性费用最小为目标函数的组合优化问题。结合油田配电网的分段开关类型和馈线自动化方式,给出了配电网开关配置的数学模型。应用蚁群算法(ACA)求解分段开关的位置和数量,并对蚁群算法的初始信息素赋值、搜索空间、转移原则和更新原则进行了改进,克服了基本蚁群算法搜索时间长、易陷入局部最优解的缺点。实例分析表明,该算法全局搜索能力强,搜索时间短,收敛速度快。  相似文献   

4.
建立有时间窗车辆路径问题的数学模型,针对遗传算法在局部搜索能力方面的不足,提出将模拟退火算法与遗传算法相结合,从而构造有时问窗车辆路径问题的混合遗传算法,并进行实验计算.结果表明,用混合遗传算法求解该优化问题,可以在一定程度上克服遗传算法在局部搜索能力方面的不足和模拟退火算法在全局搜索能力方面的不足,从而得到质量较高的解.  相似文献   

5.
配电网分段开关优化配置,可以减少用户停电损失,提高供电可靠性。分段开关优化配置是一种以可靠性费用最小为目标函数的组合优化问题。结合油田配电网的分段开关类型和馈线自动化方式,给出了配电网开关配置的数学模型。应用蚁群算法(ACA)求解分段开关的位置和数量,并对蚁群算法的初始信息素赋值、搜索空间、转移原则和更新原则进行了改进,克服了基本蚁群算法搜索时间长、易陷入局部最优解的缺点。实例分析表明,该算法全局搜索能力强,搜索时间短,收敛速度快。  相似文献   

6.
捷联惯导系统粗对准结束后,可以用遗传算法来搜索三个误差角,且由于遗传算法的全局寻优能力,在速度上具有很大优势。但遗传算法的局部寻优能力不足,因此得到的结果在精度上也受到了限制。模拟退火算法容易陷入局部最优解,但是具有很强的微调能力。因此,将遗传算法和模拟退火算法结合起来,能很好地解决初始对准的速度和精度的问题。仿真结果证明遗传模拟退火算法可以很好地改善单一遗传算法的局部寻优能力,使得结果精度更高。  相似文献   

7.
由于遗传算法解决问题时容易陷入局部极值点,根据遗传算法全局搜索能力强和模拟退火算法局部搜索能力优的特点,将它们混合使用,同时改进初始群体产生方法,使随机产生的初始群体之间有较明显的差别,能均匀分布在解空间,并采取与进化代数相关的多精英保留策略及改进的自适应选择与变异操作.模拟退火算法的结束条件改进为当连续五代个体与前一代适应值无变化或当前温度小于结束温度.仿真实验表明新算法在求解多峰值问题时改善了遗传算法的局部搜索能力,有效地解决了遗传算法的早熟现象,显著提高了遗传算法求得全局解的概率.  相似文献   

8.
加入局部搜索的非劣分层多目标遗传算法   总被引:1,自引:0,他引:1  
针对非劣分层多目标遗传(NSGA)本身所存在的局部搜索能力和易早熟的问题,鉴于模拟退火算法的局部搜索能力强和在解决易早熟问题上的优势,提出了加入局部搜索的多目标遗传算法及适用于多目标优化的模拟退火局部搜索算法和跳转准则,即在NSGA的每一代个体中的1层、2层非劣解附近进行模拟退火局部搜索.该算法能够提高非劣分层多目标遗传算法的效率,弥补了遗传算法中局部搜索能力差、易早熟的缺点.最后给出的仿真结果表明了这种算法的有效性.  相似文献   

9.
模拟退火算法是以固体退火过程为物理背景的全局优化算法,具有全局寻优的能力,是一种有效的非线性组合优化算法。模拟退火反演算法实质是利用了地球物理反演问题求解过程与熔化固体退火过程的相似性,模拟其达到最低能量状态为系统目标函数的最优解。本文概要地介绍了模拟退火法的基本原理,解的接受准则,模拟退火法的实现方法、特点及其局限性。总结了近年来对模拟退火方法进行的改进,并给出了模拟退火法在多层密度界面反演中的实例。  相似文献   

10.
将模拟退火算法和遗传算法、粒子群优化算法分别进行结合,形成模拟退火-遗传算法以及模拟退火-粒子群优化算法,并作性能对比分析。研究结果表明,这两种算法都在进化代数和全局寻优能力方面有较大突破,在找寻最佳个体解的效率士,模拟退火-粒子群优化算法更突出。  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 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   

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.
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   

15.
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   

16.
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   

17.
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   

18.
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   

19.
Quality traits in wheat (Triticum aestirum L.) were studied by quantitative trait locus (QTL) analysis in a recombinant inbred line (RIL) population, a set of 131 lines derived from Chuan 35050 × Shannong 483 cross (ChSh). Grains from RILs were assayed for 21 quality traits related to protein and starch. A total of 35 putative QTLs for 19 traits with a single QTL explaining 7.99-40.52% of phenotypic variations were detected on 10 chromosomes, 1D, 2A, 2D, 3B, 3D, 5A, 6A, 6B, 6D, and 7B. The additive effects of 30 QTLs were positive, contributed by Chuan 35050, the remaining 5 QTLs were negative with the additive effect contributed by Shannong 483. For protein traits, 15 QTLs were obtained and most of them were located on chromosomes 1 D, 3B and 6D, while 20 QTLs for starch traits were detected and most of them were located on chromosomes 3D, 6B and 7B. Only 7 QTLs for protein and starch traits were co-located in three regions on chromosomes 1D, 2A and 2D. These protein and starch trait QTLs showed a distinct distribution pattern in certain regions and chromosomes. Twenty-two QTLs were clustered in 6 regions of 5 chromosomes. Two QTL clusters for protein traits were located on chromosomes 1D and 3B, respectively, three clusters for starch traits on chromosomes 3D, 6B and 7B, and one cluster including protein and starch traits on chromosome 1D.  相似文献   

20.
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   

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