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1.
针对传统单一启发式方法解决VRP(Vehicle Routing Problem)问题解质量不高的问题,提出一种新的混合算法。该混合算法以随机近邻启发算法作为初始解,结合嵌入"退火机制"的变邻域VNS(Variable Neighbour Search)搜索算法解决车辆路径问题。实验结果表明,改进算法收敛速度较快,且解决了变邻域搜索易陷入局部最优的问题。  相似文献   

2.
飞行冲突解脱是航空器安全运行的关键,粒子群优化(particle swarm optimization,PSO)算法和变邻域搜索(variable neighborhood search,VNS)算法都可以用于解决飞行冲突,但PSO算法接近最优解时收敛速度降低,VNS算法的全局搜索能力较差。为融合PSO算法全局搜索的快速收敛特性和VNS算法的局部搜索能力,提出了变邻域搜索改进的粒子群优化算法。仿真结果证明该算法能够快速搜索到全局最优解,继承了二者的优势,同时提高了最终解脱航迹的适应值,并减少了收敛时间。  相似文献   

3.
建立了与工艺规划集成的调度问题的数学模型.以最大完工时间为目标,设计一种混合文化基因算法求解该问题.在提出算法中,设计了新型编码和主动解码方案,使用变邻域搜索(VNS)算法进行局部搜索,引入了高效的邻域结构以强化算法的局部搜索能力,并提出了一种个体扰动方法,以避免群体多样性趋于单一,使得提出算法在分散搜索和集中搜索之间达到更合理的平衡.为测试算法的性能,对现有的基准问题进行了测试,有21个实例达到了下界或得到改进,成为当前新的最优解.对比已有的最优结果可见:提出的算法可高效地求解工艺规划与车间调度集成问题且优于其他算法.  相似文献   

4.
针对车间调度问题, 提出一种新的基于粒子群优化和模拟退火的混合算法. 该算法将问题规模作为启发式信息, 通过对模拟退火算法引入新的邻域搜索机制--多粒度搜索, 并加入选择优化和淘汰更新机制, 提高了算法的自适应性和自学习能力, 降低了粒子群算法陷入局部最优的可能性. 实验结果表明, 该算法在最优解的求解能力上优于其他算法.  相似文献   

5.
针对车间调度问题,提出一种新的基于粒子群优化和模拟退火的混合算法.该算法将问题规模作为启发式信息,通过对模拟退火算法引入新的邻域搜索机制——多粒度搜索,并加入选择优化和淘汰更新机制,提高了算法的自适应性和自学习能力,降低了粒子群算法陷入局部最优的可能性.实验结果表明,该算法在最优解的求解能力上优于其他算法.  相似文献   

6.
将基本候鸟迁徙优化(Migrating birds optimization, MBO)算法与变邻域搜索策略相结合,提出了一种混合候鸟迁徙优化(Hybrid migrating birds optimization, HMBO)算法求解以最小化最大完工时间为目标的柔性作业车间调度问题(Flexible job shop scheduling problem, FJSP).首先,给出了两段式编码/解码方式.为了保证初始解的质量和多样性,设计了一种两阶段种群初始化方法;其次,引入了一种个体重置机制,以避免算法陷入局部最优解.根据FJSP问题的特点,采用3种邻域结构用于构造个体邻域解,并以此为基础设计了一种变邻域搜索算法,增强算法的局部搜索能力.最后,通过基准算例测试了算法的性能,实验数据验证了本文算法在求解FJSP问题方面的有效性.  相似文献   

7.
针对作业车间调度问题(Job shop scheduling problem,JSP),提出了一种改进型蝙蝠算法(Improved bat algorithm,IBA)以优化车间内工件的最大完工时间.根据作业车间调度问题的特点以及基本蝙蝠算法的搜索机制,首先对个体位置向量进行了设计,实现了蝙蝠算法中离散问题的连续编码;然后分别采用GT算法和随机生成两种方法对算法种群进行初始化,以提高初始解的质量.此外,采用三种邻域结构,并在此基础上设计了变邻域搜索策略作用于最优个体,以避免算法出现早熟收敛,提高IBA算法的性能.最后,针对JSP问题的基准算例进行了大量的仿真实验,计算结果验证了本文所提出的IBA算法的可行性和有效性.  相似文献   

8.
提出一种求解安全约束机组组合(security constrained unit commitment,SCUC)问题的邻域搜索外逼近(outer approximation based on neighborhood search,NS-OA)法. OA将SCUC问题分解为一系列混合整数线性规划(mixed integer linear programming,MILP)主问题和非线性规划(nonlinear programming,NLP)子问题,通过MILP主问题和NLP子问题的最优解来逼近SCUC问题的最优解.为克服迭代过程中MILP主问题规模大的不足,利用SCUC问题对应UC问题的最优解为中心来构造邻域,然后在此邻域内搜索MILP主问题的最优解.数值结果表明,所提邻域搜索能有效减小搜索空间,大大提高了算法的计算效率,所提NS-OA算法能有效求解大规模SCUC问题,具有良好的应用前景.  相似文献   

9.
求解VRPBTW的变邻域搜索算法   总被引:1,自引:0,他引:1  
以电子商务环境下物流配送为背景,建立了带有时间窗和回程载货约束的车辆路径问题优化模型,设计了改进的变邻域搜索求解算法.该算法采用改进的Braysy顺序插入法生成问题初始解,再根据变邻域搜索算法机制应用4种不同搜索范围的局域搜索算子对初始解进行改进.通过对多个算例的求解实验,并与采用一般流程的变邻域搜索算法进行比较,结果表明所提出的变邻域搜索算法的求解效果明显优于采用一般流程的变邻域搜索算法,是求解该类问题的有效算法.  相似文献   

10.
针对处理时间不确定情况下带并行机的混合Flow Shop调度问题,基于模糊规划理论,采用一种模糊数排序的方法建立了调度模型;以最小化加权模糊最大完工时间的平均值和不确定度作为调度目标,提出一种改进分布估计算法(IEDA)求解上述问题。IEDA算法采用基于NEH(Nawaz-Enscore-Ham)和破坏重建策略的初始化方法,对较优个体进行变邻域局部搜索以提高算法的局部搜索能力,同时采用破坏重建策略增加种群多样性,在最优解连续若干代没有改进时对其进行基于破坏重建策略的变邻域局部搜索,增强算法跳出局部最优的能力,并用正交设计的方法调节算法参数。仿真实验结果验证了本文算法的优越性。  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.
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.
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   

14.
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   

15.
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   

16.
AcomputergeneratorforrandomlylayeredstructuresYUJia shun1,2,HEZhen hua2(1.TheInstituteofGeologicalandNuclearSciences,NewZealand;2.StateKeyLaboratoryofOilandGasReservoirGeologyandExploitation,ChengduUniversityofTechnology,China)Abstract:Analgorithmisintrod…  相似文献   

17.
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   

18.
In the 19th century the society was controlled by men, and women were just appendants of them, they had not any rights and freedom. But Jane was an exception, she showed some characteristics of early feminist. Jane showed her characteristics of feminism in three aspects: rebellion, equality, and independence. These characteristics were helpful to her success, and feminism is the only way out for women of that time.  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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