一种基于细菌觅食优化算法的舌体分割算法

针对医学舌体数字图像的准确分割,提出了一种基于细菌觅食优化算法(BFOA) 和 Snake 活动轮廓模型相组合的舌体分割算法。首先,以信息熵与 Kapur 算法相结合作为自适 应函数来改进 BFOA 算法,通过改进的 BFOA 算法计算舌体图像的最佳图像二值化阈值,并将 舌体图像二值化;然后,利用舌体图像的对称性提取舌体的关键边缘点,并基于 B-样条插值算 法由关键点集合插值得到闭合的 B-样条曲线,作为 Snake 模型的初始轮廓;最后,通过 Snake 模型计算求解,即可准确提取舌体的轮廓曲线。实验结果表明,改进算法能够高精度地分割出 舌体图像,并能消除基本 Snake 模型在初始轮廓曲线选取中存在的人机交互难题,实现了舌体 图像的自动分割。     

Host marking pheromone ofRhagoletis cerasi: Foraging behavior in response to synthetic pheromonal isomers

We studied the foraging behavior ofRhagoletis cerasi females in trees treated with synthetic cherry fruit fly host marking pheromone (HMP) under seminatural conditions (potted trees enclosed in a screen cage). Results show that synthetic HMP (particularly the 8RS-@#@ 15R isomer configuration (racemic mixture)) was highly effective in eliciting behavioral responses similar to those reported in studies using natural HMP. Flies exposed to synthetic pheromone exhibited short tree residence times (i.e., emigrated faster), increased flight frequency rates (measured as number of alightings per/minute), higher irritation indices while on a tree or a fruit, and oviposited fewer eggs per fruit visit than flies exposed to clean trees and fruit (not treated with synthetic HMP). Furthermore, we provide evidence showing that when flies were continuously exposed to an HMP-saturated environment, they exhibited an increased tendency to lay eggs in marked fruit.     

自适应双向菌群优化算法

提出了自适应双向菌群优化算法,应用聚类思想将趋化步长进行自适应调整,提高算法的局部搜索能力,引入双向游动机制,提高了算法的搜索效率和速度。针对10个复杂Benchmark函数进行了数值优化实验,其结果表明,在所有测试函数中,该算法在搜索能力和稳定性等方面优于其他典型算法的比率达到60%～90%,验证了算法的有效性。     

基于改进细菌觅食的协作学习分组算法

针对协作学习中基于学习者特征的分组方式对学习过程的影响,设计一种基于改进细菌觅食的协作学习分组算法。在实现协作学习分组过程中,引入分组调节因子和特征权值,满足不同教学活动对学习者多个特征及分组的要求。为构成有效的分组空间,在细菌种群初始化中,细菌群体以实数编码,并加入随机扰动以增加细菌种群的多样性;在算法后期加入二次变异操作,以避免细菌觅食算法可能出现的早熟收敛现象。仿真实验结果表明,该算法在不同分组形式下,与传统算法相比,具有较优的分组性能和较高的准确率,并且对于不同数据集规模具有良好的稳定性。     

Role of trail pheromone in foraging and processionary behavior of pine processionary caterpillars Thaumetopoea pityocampa

Although caterpillars of Thaumetopoea pityocampa may mark their pathways with silk, this study shows that the material is essential to neither the elicitation nor maintenance of trail-following or processionary behavior. Trail following is dependent upon a pheromone the caterpillars deposit by brushing the ventral surfaces of the tips of their abdomens against the substrate. Earlier instars are strongly bound to their trail system; in the laboratory, caterpillars followed circular trails continuously for as long as 12 hr before breaking away from them. The trail pheromone is long-lived and soluble in nonpolar solvents, but its volatilization or degradation allows the caterpillars to distinguish new from aged trails. In contrast to trail following, processionary behavior, the head-to-tail, single-file movement of the caterpillars is dependent on neither silk nor the trail pheromone. Stimuli associated with setae found on the tip of the abdomen of the precedent caterpillar serve to hold processions together, and such stimuli take priority over those associated with either the trail pheromone or silk. Although the caterpillars discern trail strength and choose stronger over weaker trails, the trail marking system of the processionary caterpillar appears less sophisticated than those of other, previously studied species of social caterpillars, and colonies are relatively inefficient in abandoning exhausted feeding sites in favor of new food finds. In laboratory studies, females were more likely to lead processions than males, and leaders, regardless of gender, expended more energy in locomotion than followers.     

Hybrid BFOA–PSO algorithm for automatic generation control of linear and nonlinear interconnected power systems

In the bacteria foraging optimization algorithm (BFAO), the chemotactic process is randomly set, imposing that the bacteria swarm together and keep a safe distance from each other. In hybrid bacteria foraging optimization algorithm and particle swarm optimization (hBFOA–PSO) algorithm the principle of swarming is introduced in the framework of BFAO. The hBFOA–PSO algorithm is based on the adjustment of each bacterium position according to the neighborhood environment. In this paper, the effectiveness of the hBFOA–PSO algorithm has been tested for automatic generation control (AGC) of an interconnected power system. A widely used linear model of two area non-reheat thermal system equipped with proportional-integral (PI) controller is considered initially for the design and analysis purpose. At first, a conventional integral time multiply absolute error (ITAE) based objective function is considered and the performance of hBFOA–PSO algorithm is compared with PSO, BFOA and GA. Further a modified objective function using ITAE, damping ratio of dominant eigenvalues and settling time with appropriate weight coefficients is proposed to increase the performance of the controller. Further, robustness analysis is carried out by varying the operating load condition and time constants of speed governor, turbine, tie-line power in the range of +50% to ?50% as well as size and position of step load perturbation to demonstrate the robustness of the proposed hBFOA–PSO optimized PI controller. The proposed approach is also extended to a non-linear power system model by considering the effect of governor dead band non-linearity and the superiority of the proposed approach is shown by comparing the results of craziness based particle swarm optimization (CRAZYPSO) approach for the identical interconnected power system. Finally, the study is extended to a three area system considering both thermal and hydro units with different PI coefficients and comparison between ANFIS and proposed approach has been provided.     

改进细菌觅食优化算法在贝叶斯网络结构学习中的应用

针对目前已有的贝叶斯网络结构学习算法一般存在算法易早熟、学习效果不理想、算法效率较低等问题,提出了基于改进细菌觅食优化算法的贝叶斯网络结构学习策略,对传统细菌算法中的趋化算子、繁殖算子和迁移算子进行了改进。将自适应理论应用于细菌游动步长的计算和繁殖个体的选择中;在迁移算子的迁移概率计算中,引入了遗传算法中的轮盘赌方法;在互信息理论的基础上,给出了一种新的网络结构随机进化方法,代替了传统细菌算法中的随机迁移。对不同规模的经典贝叶斯网络进行了仿真实验。研究结果表明,该算法在贝叶斯网络结构学习方面,在收敛性上表现稍逊于别的算法,但在学习效果上,特别是针对结构相对复杂的网络,优势明显。     

Foraging mode and evolution of strike-induced chemosensory searching in lizards

Strike-induced chemosensory searching (SICS) in lizards and snakes is a means of relocating prey by scent-trailing. The two main components of SICS are an elevated tongue-flick rate for vomerolfactory sampling after biting prey (PETF) and searching movements. In combination, these behaviors permit scent-trailing. Prey chemical discrimination, which is a prerequisite for SICS, is present in active foragers, but not in ambush foragers. Using comparative data, I show that searching movements and SICS have undergone correlated evolution with foraging mode and with prey chemical discrimination in lizards. This suggests that active foraging selects for prey chemical discrimination, which is then employed to search for escaped prey using the typical movements and tongue-flicking behaviors of active foragers. SICS in lizards is simply heightened active foraging after biting prey. In nonvenomous snakes, SICS is similar to that in lizards but is not restricted to active foragers. Only highly venomous snakes voluntarily release dangerous prey upon envenomation, pause to let the venom incapacitate the prey, and then relocate the prey by scent-trailing. PETF was observed in two ambush foragers and is not evolutionarily correlated with foraging mode or searching movements. Because it occurs in species lacking prey chemical discrimination, such PETF may be a response to gustatory cues or to internal chemicals not encountered on surfaces or trails of uninjured prey.     

FORAGING IN CHEMICALLY DIVERSE ENVIRONMENTS: ENERGY,PROTEIN, AND ALTERNATIVE FOODS INFLUENCE INGESTION OF PLANT SECONDARY METABOLITES BY LAMBS

Interactions among nutrients and plant secondary metabolites (PSM) may influence how herbivores mix their diets and use food resources. We determined intake of a food containing a mix of terpenoids identified in sagebrush (Artemisia tridentata) when present in isoenergetic diets of increasing concentrations of protein (6, 9, 15, or 21% CP) or in isonitrogenous diets of increasing concentrations of energy (2.17, 2.55, 3.30, or 3.53 Mcal/kg). Lambs were offered choices between those diets with or without terpenes or between diets with terpenes and alfalfa hay. Intake of the diets with terpenes was lowest with the lowest concentrations of protein (6%) and energy (2.17 Mcal/kg) in the diets, and highest with diets of 15% CP and 3.53~Mcal/kg. In contrast, when terpenes were absent from the diets, lambs consumed similar amounts of all four diets with different concentrations of protein, and more of the diets with intermediate amounts of energy. When given a choice between the diet with or without terpenes, lambs preferred the diet without terpenes. When lambs were offered choices between terpene-containing diets and alfalfa, energy and protein concentrations influenced the amount of terpenes animals ingested. Energy densities higher than alfalfa, and protein concentrations higher than 6%, increased intake of the terpene-containing diet. Thus, the nutritional environment interacted with terpenes to influence preference such that lambs offered diets of higher energy or protein concentration ate more terpenes when forced, but not when offered alternative food without terpenes. The nutrients supplied by a plant and its neighbors likely influence how much PSM an animal can ingest, which in turn may affect the dynamics of plant communities, and the distribution of herbivores in a landscape. We discuss implications of these findings for traditional views of grazing refuges and varied diets in herbivores.     

改进细菌觅食算法求解柔性作业车间调度问题

针对柔性作业车间调度问题的NP难特性,提出一种改进的细菌觅食优化算法。采用集成法策略同时求解柔性作业车间调度问题的机器分配和工序调度子问题。将细菌个体表示为工序串,建立问题和算法的映射关系;分别针对普通细菌个体和当前最优个体设计了多重趋化操作,以增强算法的局部搜索能力;复制操作设置繁殖阈和死亡阈,以提高对历史经验的继承程度;迁移/驱散操作中,结合改进的LPT启发式规则,提出带倾向性的迁移/驱散操作方式。采用正交试验对算法的重要参数进行了优化配置,通过搜索算子优化效果对比实验证明了正交试验的结论;进行了收敛性能对比实验,证明算法具有优秀的全局开发能力和局部探索能力;典型算例实验结果表明,该算法能够有效求解柔性作业车间调度问题。