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1.
通过修正经典宽邻域算法的搜索方向, 提出一种新的求解线性规划问题的宽邻域内点算法, 并对算法进行收敛性分析, 证明了该算法具有经典宽邻域算法的迭代复杂性界O(nL). 数值实验表明算法是有效的.  相似文献   

2.
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   

3.
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   

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.
针对锅炉燃烧系统智能算法建模,为克服标准粒子群(PSO)优化算法对最小二乘支持向量机(LSSVM)模型参数进行优化时容易陷于局部最优解的缺点,提出一种改进型的蚂蚁?粒子群算法(MAPSO)对LSSVM模型参数进行优化.根据模式搜索的"探测"思想,通过与蚁群算法移动规则的结合改进粒子群算法,增加粒子群算法的小步长局部搜索...  相似文献   

6.
董伟 《山东科学》2011,24(1):93-96
本文将变邻域搜索算法应用到k-card问题求解中,重新定义了一种邻域结构,改进了算法,使得邻域内可行解的搜索速度得以加快,并提高了近似解的质量。对几个实际问题进行了数值实验,并与现有邻域结构的变邻域搜索算法进行了对比,实验结果证明了改进变邻域搜索算法对k-card问题的有效性。  相似文献   

7.
基于最小均方误差准则,将自适应波束形成的权值求解问题表示为多目标优化模型,利用提出的改进粒子群优化算法,获得了阵列最优权值向量.改进粒子群优化算法中引入动态邻域拓扑结构,自适应调整粒子的领域搜索范围,避免粒子陷入局部最优.仿真结果表明:所提算法的收敛速度优于传统算法.  相似文献   

8.
针对物流配送中的带有容量约束的车辆路径优化问题,提出了一个基于多邻域的迭代局部搜索算法HILS.首先用简单插入法构造可行解,然后从该初始解出发,在多邻域内进行局部优化.当陷入局部最优解后,根据解的接受准则,选择某个解,并对该解进行扰动,然后从扰动后的解出发重新进行局部优化.为提高搜索效率,局部优化过程只在限定邻域内进行.在国际通用的14个benchmark问题上进行仿真实验,结果验证了本文算法HILS的有效性和稳定性,与文献中的其他几种算法的比较结果表明,算法HILS的总体性能更优.  相似文献   

9.
从工程实际角度引出实用点的概念,指出对于一个优化问题而言,在某些场合不仅要考虑目标函数的全局极值点,还要考虑函数在此极值点邻域内的性质,进而提出实用最优点的概念——带有一定邻域约束的全局最优点.由于该约束采用传统方法难以处理,文中采用邻域采样的近似方法,基于粒子群优化算法的思想,提出了一种快速搜索算法,以求取不同要求下的实用最优点.仿真实验结果验证了实用最优点的概念以及搜索算法的可行性,该搜索算法具有良好的寻优性能.  相似文献   

10.
针对对位差分进化算法依然存在探索能力差和早熟收敛问题,提出一种基于均匀邻域对位的自适应差分进化算法。该算法在对位点所在局部邻域作适应性的小幅均匀变异操作,用以扩大对位点的搜索区域,从而提高跳出局部陷阱的概率;在对位点均匀变异操作中,变异步长利用当前群体中所有个体在每一维度的最大最小值的差距作自适应的调节,通过实时利用群体信息平衡了全局搜索与局部勘探的关系,提高算法的收敛速度;在算法搜索过程中引入多阶段扰动策略,以进一步增加算法群体实时多样性与算法所处搜索阶段的适应性,算法后期在一定程度上加强了对当前解所在邻域内的精细搜索。采用CEC 2014中不同类型基准测试函数进行仿真实验,并与其他差分算法进行对比,所提算法在10个测试函数上都取得最优的平均结果,证明所提算法具有更稳定、更优异的算法性能和更好的收敛精度。  相似文献   

11.
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   

12.
AcomputergeneratorforrandomlylayeredstructuresYUJia shun1,2,HEZhen hua2(1.TheInstituteofGeologicalandNuclearSciences,NewZealand;2.StateKeyLaboratoryofOilandGasReservoirGeologyandExploitation,ChengduUniversityofTechnology,China)Abstract:Analgorithmisintrod…  相似文献   

13.
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   

14.
Various applications relevant to the exciton dynamics,such as the organic solar cell,the large-area organic light-emitting diodes and the thermoelectricity,are operating under temperature gradient.The potential abnormal behavior of the exicton dynamics driven by the temperature difference may affect the efficiency and performance of the corresponding devices.In the above situations,the exciton dynamics under temperature difference is mixed with  相似文献   

15.
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   

16.
17.
The explosive growth of the Internet and database applications has driven database to be more scalable and available, and able to support on-line scaling without interrupting service. To support more client's queries without downtime and degrading the response time, more nodes have to be scaled up while the database is running. This paper presents the overview of scalable and available database that satisfies the above characteristics. And we propose a novel on-line scaling method. Our method improves the existing on-line scaling method for fast response time and higher throughputs. Our proposed method reduces unnecessary network use, i.e. , we decrease the number of data copy by reusing the backup data. Also, our on-line scaling operation can be processed parallel by selecting adequate nodes as new node. Our performance study shows that our method results in significant reduction in data copy time.  相似文献   

18.
R-Tree is a good structure for spatial searching. But in this indexing structure,either the sequence of nodes in the same level or sequence of traveling these nodes when queries are made is random. Since the possibility that the object appears in different MBR which have the same parents node is different, if we make the subnode who has the most possibility be traveled first, the time cost will be decreased in most of the cases. In some case, the possibility of a point belong to a rectangle will shows direct proportion with the size of the rectangle. But this conclusion is based on an assumption that the objects are symmetrically distributing in the area and this assumption is not always coming into existence. Now we found a more direct parameter to scale the possibility and made a little change on the structure of R-tree, to increase the possibility of founding the satisfying answer in the front sub trees. We names this structure probability based arranged R-tree (PBAR-tree).  相似文献   

19.
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   

20.
The geographic information service is enabled by the advancements in general Web service technology and the focused efforts of the OGC in defining XML-based Web GIS service. Based on these models, this paper addresses the issue of services chaining,the process of combining or pipelining results from several interoperable GIS Web Services to create a customized solution. This paper presents a mediated chaining architecture in which a specific service takes responsibility for performing the process that describes a service chain. We designed the Spatial Information Process Language (SIPL) for dynamic modeling and describing the service chain, also a prototype of the Spatial Information Process Execution Engine (SIPEE) is implemented for executing processes written in SIPL. Discussion of measures to improve the functionality and performance of such system will be included.  相似文献   

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