卫星电视接收天线准确定位的实验教学方法探究

针对卫星电视接收实验教学中存在的问题,对其实验教学方法进行了认真的探讨,提出了实验教学的改进方法,并进行了有益的尝试.     

消拖船节油航速优化研究

针对港口作业消拖船主机的高油耗问题,本文从船舶管理节能的角度出发,提出了基于改进天牛须算法的消拖船节油航速优化方法。通过分析消拖船的船、机、浆的能量传递机制,建立了其主机燃油消耗的优化模型,并对消拖船某航次中各航段的航速开展优化研究。天牛须算法是近年来出现的智能优化算法,在处理结构复杂的数学模型优化中优势很明显,但是也存在收敛慢、容易进入局部最优状态等问题,为此本文对其进行改进以便更好的满足应用要求。本文通过实例计算分析,采用所提出的优化算法进行消拖船主机燃油消耗优化,结果表明算法的收敛速度快,寻优效率高。与天牛须算法和蚁群算法对比分析,所提出的优化算法保持较快的运算时间的同时,提高了优化结果的准确率。     

CoMP系统中的天线选择和功率分配联合算法

在协作多点传输(coordinated multiple points transmission,CoMP)系统中,为了提高小区边缘用户传输速率和系统总吞吐量,提出了一种联合天线选择和功率分配的优化算法.在基于信道容量增量的天线选择策略(antenraselection lased on capacity increment,CIAS)中,推导了当用户端采用最大比合并时用户信道容量的表达式,并根据所设定的信道容量增量选择出所有满足条件的天线;在最优功率分配算法(optimal power allocation,OPA)中,推导了协作多点多用户系统中用户传输速率的表达式,在总功率受限的情况下通过采用优化的迭代功率分配算法,得到了最优的功率分配.理论分析和仿真结果表明,与等功率分配策略(equal power allocation,EPA)和功率与信道增益成正比的功率分配策略(proportion to channel gain,PCG)相比,联合了天线选择和功率分配的算法不仅能最大提升对边缘用户的传输速率,而且能更好地提高系统的信道容量.     

可可广翅蜡蝉成虫触角的电镜扫描

通过扫描电镜观察了可可广翅蜡蝉成虫触角的形态及其感器的类型和分布.共发现6种感器,分别为毛形感器(Ⅰ型、Ⅱ型)、锥形感器、三角形感器、耳廓形感器、腔锥形感器、柱形感器.除柱形感器外,其他类型的感器在雌、雄虫触角上的数量和分布均无较大差异,而柱形感器仅见于雌虫触角,雄虫未见.各种感器主要分布在柄节端部,而鞭节上未发现任何感器.此外,在柄节端部还发现一种由多个三角形感器和耳廓形感器形成的感器簇.     

Phylogeny and life habits of Early Arthropods-Predation in the Early Cambrian Sea

We investigated two new arthropods from the Maotianshan-Shale fauna of southern China in the course of our research on life strategies, particularly predation, in Early Cambrian marine macrofaunal biota. One form clearly belongs to the so-called "great-appendage" arthropods, animals that were, most likely, active predators catching prey with their first pair of large, specialized frontoventral appendages. Based on this, we hypothesize that the new species and many others, if not all, of the "great-appendage" arthropods were derivatives of the chelicerate stem lineage and not forms having branched off at different nodes along the evolutionary lineage of the Arthropoda. Rather, we consider the "great-appendage" arthropods as belonging to a monophyletic clade, which modified autapomorphically their first pair of appendages (antennae in general arthropod terminology) into raptorial organs for food capture. The second new form resembles another Maotianshan-Shale arthropod, Fuxianhuia protensa, in sharing a head made of only two separate segments, a small segment bearing oval eyes laterally, and another bearing a large tergite, which forms a wide shield freely overhanging the subsequent narrow trunk segments. This segment bears a single pair of rather short anteriorly directed uniramous appendages, considered as the "still" limb-shaped antennae. Particularly the evolutionary status of head and limbs of these two forms suggests that both are representatives of the early part of the stem lineage toward the crown-group of Arthropoda, the Euarthropoda. These forms appear rather unspecialized, but may have been but simple predators. This adds to our hypothesis that predation was a common, if not dominant feeding strategy in the Cambrian, at least for arthropods.     

蚱科7种昆虫触角感受器的形态与分布

报道了蚱科(Tetrigidae)7种昆虫的触角感受器的形态与分布的扫描电镜观察结果.蚱科昆虫的触角感受器数量与类型较少,仅有芽孢形感受器I、芽孢形感受器II、腔形感受器和板形感受器4种类型,其中以板形感受器数量最多.通过对7种昆虫的雌性个体触角感受器在触角各节上的分布情况的分析,发现蚱科昆虫的触角感受器主要分布于触角的端部及中段节次上,其中以板形感受器的分布最为明显,主要集中分布于第10—15节触角上.     

Suboesophageal DUM neurones are part of the antennal motor system of locusts and crickets

Summary The muscles which move the antennae of locusts and crickets are innervated by motoneurones of the deutocerebral part of the brain. In addition, these muscles receive axon collaterals of two dorsal, unpaired, median (DUM) neurones which are located in the suboesophageal ganglion. These DUM neurones also send axons towards the retrocerebral glandular complex.     

含热电联合系统的微电网运行优化

为了提高微电网的经济运行水平,提出考虑分时电价并计及制热收益的微电网多目标能量调度模型,该模型以微网发电成本最低与环境效益最优为目标。首先,利用权重系数将多目标经济调度问题化成单目标优化问题。其次,针对遗传算法局部搜索能力差的问题,提出了天牛须搜索算法改善遗传算法的变异操作,利用自身对空间的判断,加强局部搜索能力,在此基础上将Metropolis接受准则加入天牛须搜索算法中,增加变异的概率。最后,以一个微电网为例,将改进的算法与标准遗传算法进行对比,验证了所改进的算法的全局最优解的搜索能力,使得微网获得更佳的综合效益,降低了系统经济运行成本。     

基于改进神经网络及地理信息系统空间分析的风暴潮经济损失评估

台风风暴潮是影响我国最严重的海洋灾害之一,台风风暴潮经济损失的预评估对防灾减灾有重要作用。针对目前大量单机器学习模型评估效果不佳的问题,提出基于天牛须搜索算法优化的BP神经网络及GIS空间分析的台风风暴潮经济损失评估模型。该模型在神经网络训练前,先利用天牛须搜索算法对神经网络的初始权值阈值进行优化,以提高网络的寻优精度;在网络输出计算结果后,借助GIS空间分析功能找出待评估台风风暴潮的相似样本,并用相似样本对待评估台风风暴潮进行结果调整;最后基于悲观、乐观估计思想,给出台风风暴潮经济损失预评估区间。计算结果表明,结合GIS空间分析调整能给出更有效的模型评估结果。