一种改进的自适应进化粒子群优化算法

针对粒子群优化算法容易陷入局部极值点以及进化后期收敛慢和优化精度较差等缺点,提出一种改进的自适应进化算法.该算法引入信息扩散函数,根据不同粒子的位置及对应适应值与当前群体最佳位置和最佳适应值的关系,控制粒子变尺度向群体当前最佳位置移动;基于多样性反馈机制动态调节惯性权值和控制粒子群的微变异.通过复杂基准函数的仿真优化结果表明,改进算法具有抑制早熟、收敛速度快、求解精度高的特点.     

基于改进蚁群算法的移动机器人路径规划研究

为解决传统蚁群算法收敛速度慢、极易陷入局部最优解的问题,文中提出了一种改进蚁群算法,并将其应用于移动机器人路径规划问题。蚁群算法的路径规划采用栅格法建立环境模型,并对障碍物进行扩大处理,从而有效降低了移动机器人在运动过程中与障碍物相碰撞的可能性;构造启发函数以降低蚁群搜索路径的长度;引入信息素扩散算法,并提高算法在初期的全局搜索能力,从而加快了算法的后期收敛速度。仿真结果表明,所提出的算法在收敛速度上比传统蚁群算法提高近一倍,可以规划出最优路径。     

基于信息素扩散的蚁群算法

蚁群算法是一种新型的搜索算法,其模拟的是蚁群依赖信息素进行通信而表现出的社会性行为.在基本蚁群算法中,蚂蚁之间协作不足,存在滞后的缺陷.本文在分析这一算法的基础上,提出了一种新的更加忠实了真实蚁群信息系统的蚁群算法.该算法通过建立信息素扩散模型,使相距较近的蚂蚁之间能更好地进行协作.TSP问题的仿真结果表明了该算法的有效性.     

基于改进蚁群算法的无人机2 维航路规划

针对传统蚁群算法在无人机3 维航路规划中存在搜索时间长、容易陷入局部最优解的问题,提出一种蚁 群算法的改进策略。将固定翼无人机的性能约束条件作为待扩展节点是否可行的判断条件,减小计算量和算法搜索 时间;对航路点的高度规划采用直接设定策略,将3 维航路规划问题简化为2 维航路规划问题,减小算法的复杂性; 改进全局信息素更新规则和安全启发因子,解决了局部最优解和威胁源规避问题。仿真结果表明：改进蚁群算法与 传统蚁群算法相比,能够有效规划出一条从起点到终点的飞行航路,具有更高的有效性和实用性。     

改进的基于蜜蜂进化型遗传算法和蚁群系统混合的元件贴装优化

针对PCB板的表面贴装技术(Surface Mount Technology,SMT)优化问题,提出一种基于蜜蜂进化型遗传算法和蚁群系统的混合智能算法(the Hybrid Intelligent Algorithm based on Bee Evolutionary Genetic Algorithm and Ant Colony System,BAHA).该算法的关键有4点:①通过两个种群的融合实现信息共享,提高算法的收敛速度;②采用改进的OX的交叉算子,合理保留优秀个体基因的排列顺序;③加入局部搜索算子,在当代最优解附近进行更加精细的搜索;④信息素重置防止陷入局部最优解.用TSP30问题、eil51问题与相关文献进行对比测试,仿真结果表明BAHA收敛速度快,寻优能力强.通过对5种不同PCB板的元件贴装顺序进行优化计算,结果表明,BAHA能有效的提高贴装效率.     

Behavioral responses of malePeriplaneta americana L. to female sex pheromone components,periplanone-A and periplanone-B

Bioassays were performed on malePeriplaneta americana L. using synthetic (–)-periplanone-B (P-B) and Hauptmann's (–)-periplanone-A (P-A), and their mixtures at various ratios to estimate the roles of both periplanones for the sexual communication of the species. Both P-A and P-B elicited qualitatively the same responses, such as antennal movement, rapid locomotion, wing raising, and homosexual behavior of male cockroaches, but the threshold of the pheromone activities for P-B was two orders of magnitude lower than that of P-A. Neither synergistic nor inhibitory but only a simple integrated effect on the responses was observed when mixtures of P-A and P-B were applied.     

Release rates of tetradecen-1-ol acetates from polymeric formulations in relation to temperature and air velocity

An apparatus was developed for investigating the release rates of pheromone formulations at temperatures and air velocities that correspond with those in the field. Polyurethane foam proved an excellent adsorbent for the recovery of tetradecen-1-ol acetates, allowing high air flows at low differential pressure and without breakthrough of these compounds. The experimental setup and procedures are described. The release rates of all formulations investigated were almost proportional to the square root of air velocity, and their logarithms were proportional to the reciprocal of temperature (K). When temperature is increased from 15°C to 25°C, the release rates increase by about 2-2.5 ×. Both relationships were combined into one equation that allows a reliable estimate to be made of the actual release rates of a formulation, under varying conditions, on the basis of its specific parameters and the relevant meteorological data.     

Inhibitory pheromonal activity promoted by sulfur analogs of the sex pheromone of the female processionary mothThaumetopoea pityocampa (Denis and schiff)

New sulfur analogs of the sex pheromone of the female processionary mothThaumetopoea pityocampa have been found to be effective inhibitors of the natural pheromone activity both in EAG bioassays and field tests. The structures of these analogs have been derived from replacement of the oxygen atom(s) of the acetate group by sulfur (compounds 3-5) and the olefinic moiety of the enyne function by the isosteric SCH₂ group (compounds 6 and 7). The synthesis and biological activity of 3-[(Z)-12-pentadecen-10-ynylthio]-1,1,1-trifluoropropan-2-one (8), a closely related structure to the pheromone is also described.     

Male sternal pheromone glands in Acanthosomatid shield bugs from Britain

Pheromone glands are present in the abdominal sternites of the pregenital region in the male adults in all British species of Acanthosomatidae. Secretory units are most numerous in the hawthorn bugAcanthosoma haemorrhoidale and maternal bugElasmucha grisea, next most numerous in the birch bugElasmostethus interstinctus, and least numerous in the juniper bugCyphostethus tristriatus. The largest dorsal abdominal scent glands were found inCyphostetheus. Ordinary dermal glands are also present. They are most numerous along the lateral margins of the abdomen. It is possible that Pendergrast's organ is the source of a female-produced pheromone. Secretory units were numerous in this organ inC. tristriatus female adults.     

Male pheromone of swift moth,Hepialus hecta L. (Lepidoptera: Hepialidae)

(R)-6-Ethyl-2-methyl-2,3-dihydro-4H-pyran-4-one, (1R,3S,5R)-3-ethyl-1,8-dimethyl-2,9-dioxabicyclo[3.3. 1]non-7-ene, and (1R,3S,5R)-3-ethyl-1,8-dimethyl-2,9-dioxabicyclo[3.3.1]non-7-en-6-one represent the main components in the male pheromone of the swift moth,Hepialus hecta. The amounts of the three components were 40, 5, and 5 g per male, respectively. Structure elucidation of the compounds was based on spectroscopic data as compared to synthetic reference samples. The absolute configurations were determined by gas chromatography on chiral stationary phases; optically active samples served as reference compounds. Electrophysiological and behavioral experiments with natural material and synthetic samples clearly showed the three heterocyclic compounds to act as pheromones. (E, E)--Farnesene represents the main component of the scent secretion of maleHepialus humuli.