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排序方式: 共有926条查询结果,搜索用时 296 毫秒
81.
针对目前人工蜂群算法的早熟收敛、陷入局部极值等问题,提出一种基于混沌鲶鱼效应的改进人工蜂群算法.首先,采用随机性更高的混沌序列初始化蜂群以扩大其遍布范围;其次,集成了鲶鱼效应和混沌理论提出了混沌鲶鱼蜂,并引入了它与跌入局部极值的蜂群之间的有效竞争协调机制,从而增进蜜蜂群体跳出局部最优解、加速收敛的能力.支持向量机的学习能力主要取决于其惩罚因子C和核函数参数的合理选择,对其参数的优化可以提升其学习效果,然而现行算法均存在一定局限性.基于我们提出的改进人工蜂群算法,对支持向量机的参数进行了优化.最后,在UCI(加州大学欧文分校)数据集和行为识别真实数据集上进行了测试,验证基于改进人工蜂群算法的支持向量机具有更强的分类性能. 相似文献
82.
Hao Sun Haim Waisman Raimondo Betti 《International journal for numerical methods in engineering》2014,100(7):477-503
We present a novel multiscale algorithm for nondestructive detection of multiple flaws in structures, within an inverse problem type setting. The key idea is to apply a two‐step optimization scheme, where first rough flaw locations are quickly determined, and then, fine tuning is applied in these localized subdomains to obtain global convergence to the true flaws. The two‐step framework combines the strengths of heuristic and gradient‐based optimization methods. The first phase employs a discrete‐type optimization in which the optimizer is limited to specific flaw locations and shapes, thus converting a continuous optimization problem in the entire domain into a coarse discrete optimization problem with limited number of choices. To this end, we develop a special algorithm called discrete artificial bee colony. The second phase employs a gradient‐based optimization of the Broyden–Fletcher–Goldfarb–Shanno type on local well‐defined and bounded subdomains determined in the previous phase. A semi‐analytical approach is developed to compute the stiffness derivative associated with the evaluation of objective function gradients. The eXtended FEM (XFEM), with both circular and elliptical void enrichment functions, is used to solve the forward problem and alleviate the costly remeshing of every candidate flaw, in both optimization steps. The multiscale algorithm is tested on several benchmark examples to identify various numbers and types of flaws with arbitrary shapes and sizes (e.g., cracks, voids, and their combination), without knowing the number of flaws beforehand. We study the size effect of the pseudo grids in the first optimization step and consider the effect of modeling error and measurement noise. The results are compared with the previous work that employed a single continuous optimization scheme (XFEM–genetic algorithm and XFEM–artificial bee colony methods). We illustrate that the proposed methodology is robust, yields accurate flaw detection results, and in particular leads to significant improvements in convergence rates compared with the previous work. Copyright © 2014 John Wiley & Sons, Ltd. 相似文献
83.
In this study the layer optimization was carried out for maximizing the lowest (first) fundamental frequency of symmetrical laminated composite plates subjected to any combination of the three classical boundary conditions, and the applicability of the Artificial Bee Colony (ABC) algorithm to the layer optimization was investigated. The finite element method was used for calculating the first natural frequencies of the laminated composite plates with various stacking sequences. The ABC algorithm maximizes the first natural frequency of the laminated composite plate defined as an objective function. The optimal stacking sequences were determined for two layer numbers, twenty boundary conditions and two plate length/width ratios. The outer layers of the composite plate had a stiffness increasing effect, and as the number of clamped plate edges was increased both he stiffness and natural frequency of the plate increased. The optimal stacking sequences were in good agreement with those determined by the Ritz-based layerwise optimization method (Narita 2003: J. Sound Vibration 263 (5), 1005–1016) as well as by the genetic algorithm method combined with the finite element method. 相似文献
84.
利用混沌的特点设计了一种混沌局部搜索算子,将该算子加入到原始人工蜂群算法中提出了一种混沌蜂群算法(CABC),并用之来优化焊接条的结构设计问题。该问题的目标是在满足约束条件下使得制造焊接条所需的总费用最小,是一个典型多维多约束非线性规划问题。为了不让人工蜂群算法优化该问题时陷入局部最优解,在原始蜂群算法末期的最优值附近进行混沌局部搜索,使其跳出局部最优,有效提高了算法的局部寻优能力。最后对焊接条设计问题进行了仿真计算,并将结果与其他文献中的结果进行了对比,显示了混沌人工蜂群算法优化焊接条设计问题的优越性。 相似文献
85.
针对任务可拆分的资源受限的项目调度问题,提出了一种人工蜂群算法与任务可拆分的串行调度机制相结合的优化方法.人工蜂群算法中每个食物源的位置代表一组项目任务的优先权序列,优先权序列通过调度生成机制转换为可行调度方案,迭代中由三种人工蜂执行不同的操作来实现全局最优解的更新.实算表明,基于优先权的人工蜂群算法可以有效求解任务可拆分项目调度问题,收敛速度较快且精度较高. 相似文献
86.
针对传统的PID控制器参数整定方法中存在的整体效率低、控制效果差等问题,提出了一种改进的人工蜂群算法,在标准算法的搜索方程中引入差分进化算法的变异算子,并添加自适应调整参数,提升算法的收敛速度、增强局部寻优效果的同时,平衡了算法的全局探索和局部开发能力。实验表明,改进后的算法对PID控制器的参数整定优化有明显效果。 相似文献
87.
蜜蜂进化型遗传算法在水库优化调度中的应用 总被引:1,自引:0,他引:1
提出了一种基于蜜蜂进化型遗传算法的水库优化调度问题的求解方法,并通过实例对蜜蜂进化型遗传算法和标准遗传算法的性能做了比较.结果表明,在进化代数相同的条件下,由于蜜蜂进化型遗传算法在配种选择算子上使用种群的最优个体作为蜂王,提高了种群收敛速度;再者,在代进化过程中引入一个随机种群,保持了群体的多样性,提高了算法的勘测能力. 相似文献
88.
Otto Boecking E. Genersch 《Journal für Verbraucherschutz und Lebensmittelsicherheit》2008,3(2):221-228
Varroosis is the most destructive disease of honey bees worldwide, inflicting much greater damage and higher economic costs
than all other known apicultural diseases. The disease pattern of Varroosis is not uniform, as both the rate of infestation
and secondary infections determine the clinical symptoms. Brood and adults bees are impaired. The mite injures the bee through
repeated intake of hemolymph with her chelicerae while the host is in the larval, pupal and adult stage. The loss of hemolymph
negatively effects the organ development of the bee. Colonies infested by V. destructor develop the parasitic mite syndrome and ultimately collapse if left untreated. Favourable reproduction conditions in the
new host A. mellifera, the increasing impact of secondary infections (viruses) and the lack of coordinated and comprehensive treatment strategies
and control methods that are often implemented too late or unsuccessfully by the beekeeper result in reappearing wide spread
colony losses. A viral infection vectored by V. destructor obviously increases its impact on colony collapses with the cause of this ongoing crisis. Varroa control should be a natural part of a beekeeper’s operation and flow into a system of Varroa control. The residues from Varroacide applications which are detectable today are all below the permitted maximum values.
Although these minor detectable residues pose no threat to the consumer, they must be avoided in bee products, as honey possesses
a very positive image in the mind of consumers.
Received: February 20, 2008 相似文献
89.
90.
围绕蜂产品生产过程, 我国建立了“事前、事中、事后”监管制度, 初步建立起由法律、法规、规章、规范性文件、技术标准等构成的蜂产品生产监管法规体系, 将蜂蜜, 蜂王浆(含蜂王浆冻干粉), 蜂花粉, 蜂产品制品4类产品纳入食品生产许可范围。近年来, 我国蜂产品产量、出口量一直稳居世界前列, 质量安全处于较高水平, 但也存在一些问题。就产业而言, 主要是低端同质, 蜂蜜掺假, 果糖和葡萄糖等质量指标不合格及兽药残留。就监管而言, 主要是法规体系不完善, 标准体系难以适应行业发展; 部分企业食品安全意识淡漠, 管理制度落实不到位; 技术支撑薄弱, 生产监管体系和能力建设有待加强。做好蜂产品生产监管工作, 需多措并举, 综合施策。建议加强检验、品质评价、蜂产品制品研究; 完善相关法规、标准体系; 完善监管制度, 加强部门间政策协调与标准对接; 加强鉴别、追溯、风险预警等支撑技术建设, 实现“智慧监管”, 提高监管效能。 相似文献