叠前弹性波反演非线性优化方法

针对传统遗传算法自身存在的早熟收敛、搜索空间小以及计算效率低的问题,在保证算法收敛和最大限度地搜索模型空间的基础上,对遗传算子采取相应策略进行了改进,并通过界约束以增加解的稳定性.为了提高计算效率,采用粗粒度并行遗传算法,将并行计算机的高速并行性和遗传算法固有的并行性相结合,进行多种群并行搜索.选择合适的迁移拓扑结构和迁移策略,构建了并行模型,并给出了改进后并行遗传算法的设计流程图及详细算法描述.采用该算法进行了叠前弹性波反演的实际计算,取得了良好的效果.     

基于混合编码的粗粒度并行遗传算法在公路选线优化中的研究

首先分析公路选线设计中,采用计算机软件算法进行优化的必要性,指出由于公路选线优化上的行业特殊性,目前在提高计算效率中还存在局限性;提出一种基于混合编码的粗粒度并行遗传算法来进行公路选线优化,利用混合编码技术精简编码和子线程的通信量,利用粗粒度并行遗传算法提高多核心CPU的应用率,最终达到提高公路路线优化算法效率的目的。详细介绍了整个算法的原理和过程,并开发计算机软件系统应用到实际工程中;最后,在总结中认为,采用并行遗传算法来解决公路选线优化问题,是研究人工智能算法技术运用在公路选线优化领域中,最能提升效率并取得效果的一种途径。     

用遗传-禁忌搜索混合算法求解组合投资问题

提出了一种基于遗传算法和禁忌搜索的混合算法,用遗传算法提供并行搜索的主框架,用禁忌搜索作为遗传算法的变异算子.遗传算法中变异过程解空间的搜索由禁忌搜索实现,并且用混合算法求解了概率准则意义下的组合证券投资模型.实例证明,遗传/禁忌混合算法有较强的爬山能力,较遗传算法有更高的计算效率,为组合证券投资者提供了一种高效的决策方法.     

遗传算法解TSP问题的并行实现

遗传算法是一种概率搜索算法,其本身固有并行性。目前,人们正不断地致力于把遗传算法应用于各种并行机器上。在基于工作站机群技术上,构架了一种粗粒度并行遗传算法,并在MPI并行环境下,用4台PC机测试了一个解决TSP问题的粗粒度并行遗传算法。该并行遗传算法可以更好的保护优秀个体从而提高遗传算法的收敛性。     

面向agent的并行GA

讨论了面向agent的并行遗传算法(GA)模型,该模型属于粗粒度的并行模型,并提出了算法的实现方法 与经典粗粒度孤岛并行GA的对比分析结果表明,基于该模型的并行GA具有通讯代价小、子群体间信息交换充分等特点 此外,该模型采用多智能体技术,用agent表示群体中的个体,简化了问题,便于实现 图2,参10     

并行遗传算法收敛性分析及优化

针对并行遗传算法（parallel genetic algorithms，PGA）容易出现收敛过快和陷入局部最优解的问题，综合多种不同进化策略遗传算法之所长，设计了一种混合的粗粒度并行遗传算法。该算法由多个独立的子群体组成，各个子群体并行的、独立的、按照不同的遗传进化策略进化，每隔一定的时间，在子群体之间进行最优个体的迁移，促进群体的共同进化，并抑制群体早熟。在PVM环境下，用该算法实现函数优化问题，仿真实验数据表明了其有效性．     

一种新量子遗传算法及应用

基于量子位测量的二进制量子遗传算法,在用于连续问题优化时,由于频繁的解码运算,严重降低了优化效率。针对这一问题,提出了一种基于量子位相位编码的量子遗传算法。该方法直接采用量子位的相位对染色体进行编码,采用量子旋转门实现染色体上相位的更新,采用Pauli-Z门实现染色体的变异。在该方法中,由于优化过程统一在空间[0,2π]n进行,而与具体问题无关,因此,对不同尺度空间的优化问题具有良好的适应性。以函数极值优化为例,仿真结果表明该方法的搜索能力和优化效率明显优于普通量子遗传算法和标准遗传算法。     

遗传算法三种编码策略的比较研究

分析遗传算法的二进制、实数、十进制编码策略实现方法,根据各编码的特点,设计相应的改进遗传策略.以前馈神经网络权值优化问题为例,用计算机仿真实验的方法研究三种编码策略对各遗传算法性能的影响.研究结果表明,若同时强调搜索效率和搜索准确性,宜采用实数编码的改进遗传算法;若只强调搜索准确性,则应优先考虑十进制编码的改进遗传算法.研究的结论为遗传算法在高维连续参数优化问题中编码策略的选取提供了理论指导.     

综合遗传算法及其在地震波阻抗反演中的应用

为了有效地克服非线性、多参数、多极值的组合优化问题中遗传算法的早熟收敛现象,引入生物的小生境技术和自然界生物多种杂交方式并存、多个子群体并行以及灾变现象而提出了一种综合的快速基因搜索策略。该算法以多个子群体不同杂交方式并行搜索为主,并结合排序配对的受限交配技术和灾变算子等方法来实现快速的寻优过程。对地震资料波阻抗反演的理论模型试验表明:该算法的收敛能力和计算效率有了明显改善。     

一种多值编码遗传算法的缺失基因复现方法

与二值编码遗传算法相比,基因缺失问题对多值编码遗传算法的全局搜索性能影响比较大.提出一种缺失基因复现和存活的变异方法,即根据字符集中的字符在种群中的缺失作为预选变异基因集,然后对待变异个体集进行预变异;选择高适应度个体的对应变异基因和基因位,使其在原待变异个体集中扩散.将该方法应用到多重选择背包问题的遗传算法中,通过仿真实验验证了该方法的有效性.     

Directed self-assembly of a colloidal kagome lattice

A challenging goal in materials chemistry and physics is spontaneously to form intended superstructures from designed building blocks. In fields such as crystal engineering and the design of porous materials, this typically involves building blocks of organic molecules, sometimes operating together with metallic ions or clusters. The translation of such ideas to nanoparticles and colloidal-sized building blocks would potentially open doors to new materials and new properties, but the pathways to achieve this goal are still undetermined. Here we show how colloidal spheres can be induced to self-assemble into a complex predetermined colloidal crystal-in this case a colloidal kagome lattice-through decoration of their surfaces with a simple pattern of hydrophobic domains. The building blocks are simple micrometre-sized spheres with interactions (electrostatic repulsion in the middle, hydrophobic attraction at the poles, which we call 'triblock Janus') that are also simple, but the self-assembly of the spheres into an open kagome structure contrasts with previously known close-packed periodic arrangements of spheres. This open network is of interest for several theoretical reasons. With a view to possible enhanced functionality, the resulting lattice structure possesses two families of pores, one that is hydrophobic on the rims of the pores and another that is hydrophilic. This strategy of 'convergent' self-assembly from easily fabricated colloidal building blocks encodes the target supracolloidal architecture, not in localized attractive spots but instead in large redundantly attractive regions, and can be extended to form other supracolloidal networks.     

基因组中的简单重复序列

简单重复序列广泛分布于原核和真核基因组.目前认为SSR主要由DNA复制时聚合酶滑 动导致链错配而形成.SSR在基因组中有其特定作用.某些细菌利用SSR获得"应急基因",以适应 环境变化.而在真核基因组中,SSR被发现可作为功能性的编码和调控元件.启动子区域的SSR在 其基因表达中起增强子作用.由于SSR具有高度多态性,所以可作为一种良好的分子标记应用于 各个领域.目前已对果蝇、线虫、酵母等模式生物做了全基因组范围的SSR探查.这些工作提供了 大量的SSR分子标记,为其更细致广泛的应用奠定了基础.该文就SSR的特征、组成、进化机制以 及功能和应用做了介绍和探讨.     

The building blocks of planets within the 'terrestrial' region of protoplanetary disks

Our Solar System was formed from a cloud of gas and dust. Most of the dust mass is contained in amorphous silicates, yet crystalline silicates are abundant throughout the Solar System, reflecting the thermal and chemical alteration of solids during planet formation. (Even primitive bodies such as comets contain crystalline silicates.) Little is known about the evolution of the dust that forms Earth-like planets. Here we report spatially resolved detections and compositional analyses of these building blocks in the innermost two astronomical units of three proto-planetary disks. We find the dust in these regions to be highly crystallized, more so than any other dust observed in young stars until now. In addition, the outer region of one star has equal amounts of pyroxene and olivine, whereas the inner regions are dominated by olivine. The spectral shape of the inner-disk spectra shows surprising similarity with Solar System comets. Radial-mixing models naturally explain this resemblance as well as the gradient in chemical composition. Our observations imply that silicates crystallize before any terrestrial planets are formed, consistent with the composition of meteorites in the Solar System.     

进化计算中的精英个体产生策略

初始种群是影响基因表达式编程算法（GEP）的重要因素之一。提出了精英个体产生策略,产生具有较高的适应度的精英个体,使种群从一个较高的基础上开始进化,从而提高种群的进化效率。在此基础上,提出了综合精英个体产生策略和基因空间均匀分布策略优点的综合种群产生算法。实验表明,精英个体产生策略可以提高进化效率17%,综合算法可以更加有效地提高系统的进化效率。以上算法的思想还可以应用于其它进化计算中。     

Distributed biological computation with multicellular engineered networks

Ongoing efforts within synthetic and systems biology have been directed towards the building of artificial computational devices using engineered biological units as basic building blocks. Such efforts, inspired in the standard design of electronic circuits, are limited by the difficulties arising from wiring the basic computational units (logic gates) through the appropriate connections, each one to be implemented by a different molecule. Here, we show that there is a logically different form of implementing complex Boolean logic computations that reduces wiring constraints thanks to a redundant distribution of the desired output among engineered cells. A practical implementation is presented using a library of engineered yeast cells, which can be combined in multiple ways. Each construct defines a logic function and combining cells and their connections allow building more complex synthetic devices. As a proof of principle, we have implemented many logic functions by using just a few engineered cells. Of note, small modifications and combination of those cells allowed for implementing more complex circuits such as a multiplexer or a 1-bit adder with carry, showing the great potential for re-utilization of small parts of the circuit. Our results support the approach of using cellular consortia as an efficient way of engineering complex tasks not easily solvable using single-cell implementations.     

用不同语义单元度量的句子相似度计算

提出了一种基于不同语义单元度量的句子相似度计算方法.将句子按词块分割为对应的公共词块和非公共词块,利用外部语义资源进行同义词替换和语义消歧处理.分别用词、词块和字为语义单元度量句子相似度,以不同的权重调节各语义单元对句子相似度的贡献.实验结果表明,该方法综合考虑的因素更加全面,有较高的准确率.     

DNA-programmable nanoparticle crystallization

It was first shown more than ten years ago that DNA oligonucleotides can be attached to gold nanoparticles rationally to direct the formation of larger assemblies. Since then, oligonucleotide-functionalized nanoparticles have been developed into powerful diagnostic tools for nucleic acids and proteins, and into intracellular probes and gene regulators. In contrast, the conceptually simple yet powerful idea that functionalized nanoparticles might serve as basic building blocks that can be rationally assembled through programmable base-pairing interactions into highly ordered macroscopic materials remains poorly developed. So far, the approach has mainly resulted in polymerization, with modest control over the placement of, the periodicity in, and the distance between particles within the assembled material. That is, most of the materials obtained thus far are best classified as amorphous polymers, although a few examples of colloidal crystal formation exist. Here, we demonstrate that DNA can be used to control the crystallization of nanoparticle-oligonucleotide conjugates to the extent that different DNA sequences guide the assembly of the same type of inorganic nanoparticle into different crystalline states. We show that the choice of DNA sequences attached to the nanoparticle building blocks, the DNA linking molecules and the absence or presence of a non-bonding single-base flexor can be adjusted so that gold nanoparticles assemble into micrometre-sized face-centred-cubic or body-centred-cubic crystal structures. Our findings thus clearly demonstrate that synthetically programmable colloidal crystallization is possible, and that a single-component system can be directed to form different structures.     

河南省科学推进城镇化的政府职能研究

乡村环境治理是政府在科学推进城镇化进行中的重要职能之一,也是建设"美丽河南"重要内容。美好乡村环境治理的效果不仅取决于各级政府是否有所作为,更取决于政府是否能够调动乡村精英参与到乡村环境治理中。政府主导下乡村精英,在乡村环境治理进程中担任着宣传者、提供者、协调者和监督者多重角色。政府积极推动乡村精英队伍参与村级管理,构筑基层政府、社会组织、乡村精英和普通村民"多元互动"立体的乡村环境治理网络,实现城镇化的科学发展。     

基于区域二次划分的分形图像编码方法

提出一种基于区域二次划分的新算法．根据改进的分割一合并策略将原始的灰度图像分成若干均匀块,不满足分割条件的非均匀块单独处理并被标记为特征块,对一般的规则块按照四叉树算法进行处理,对不规则块则按新规则处理．对标准图像的实验结果表明,与全搜索的分形图像编码算法相比,平均编码时间缩短了,并且所提出的方案比基于四又树的分形图像编码方案可以获得更好的恢复图像质量和更高的压缩比．