共查询到20条相似文献，搜索用时 93 毫秒
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DNA计算机在求解大型科学问题中DNA链数呈纯指数增长的瓶颈亟待解决。本文提出一种将分治策略应用求解背包问题的新的基于质粒DNA计算机算法,使DNA链数可达到亚指数的O（1.414n）,其中n为背包问题的维数。与已有文献结论进行的对比分析表明：本算法将穷举算法中所需的DNA链数从O（2n）减少至O（1.414n）,利用本算法将可破解的背包公钥的维数在试管级水平上从60提高到120。 相似文献
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0／1背包问题是一个著名NP——复杂问题，以前人们主要用分支——限界法、贪心法等方法去解决该问题。本文主要论述了一种新的计算模式——DNA计算来解决0／1背包问题。依据分子生物学的实验方法，文中所提出的算法是有效和可行的。 相似文献
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0/1背包问题是一类典型的组合优化问题,并且是NP完全问题。针对0/1背包问题和蚁群算法的特点,设计了一个标志表,使得蚁群算法可以应用到背包问题上。仿真结果表明,改进的蚁群算法在求解0/1背包问题上是相当出色的。 相似文献
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货郎担问题是组合优化领域里的一个典型问题,是属于易于描述却难于解决的NP完全难题,有效地解决货郎担问题具有重要意义。首先给出了货郎担问题的描述,然后介绍了几种基本的解决货郎担问题的算法思想:穷举法、动态规划、回溯法以及分支限界法,并对各种算法的计算复杂度进行了比较和分析。 相似文献
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在解决NP完全问题上,DNA计算有着传统图灵机无法比拟的优势。分子信标在DNA计算和纳米技术领域起着非常重要的作用,分子信标计算模型可以解决很多NP完全问题。针对图顶点着色问题的NP完全问题,利用分子信标给出图顶点着色问题的DNA计算模型。最后,通过实例说明分子信标计算模型是可行的。 相似文献
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0-1背包问题的遗传算法求解及其改进 总被引：1，自引：0，他引：1
0-1背包问题是一个典型的组合优化问题,且为NP完全问题.目前常用的方法有贪心算法,动态规划,回溯法等.本文探讨了一种基于贪心算法的混合遗传算法求解0-1背包问题的方法,并在实验中获得了更佳近似解. 相似文献
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《佳木斯教育学院学报》2017,(4)
随着数学研究逐渐深入,对于离散数学问题探究越来越多。离散实现是数学领域中的重要分支,在离散数学中包含着很多NP完全问题,为了有效的解决这些完全问题,需要借助DNA计算方式。目前DNA计算已经成为了数学、生物、化学乃至计算机科学领域中的重点研究对象。基于此,在本文中对离散数学中NP完全问题的DNA计算进行研究。 相似文献
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排课问题早在70年代就被证明是一个NP完全问题,即算法的计算时间是呈指数增长的,这一论断确立了排课问题的理论深度。对于NP完全问题,目前在数学上还没有一个通用的算法能够很好地解决。拟人策略算法结合了多种高校排课算法实例和多年的实际排课经验,与其它算法相比,有效地避免了以往算法的高时间复杂度和高空间复杂度,简单易行,便于程序实现。 相似文献
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生物芯片技术和DNA计算分别是近几年来生命科学与信息科学的新兴研究领域,DNA计算在求解NP问题上存在着硅计算无法比拟的先天优越性。而图的最小顶点覆盖问题是图论中的一个重要问题,目前还没有好的算法。在DNA计算和DNA计算芯片的基础上,采用分子信标编码策略,利用观察荧光来确定图的最小顶点覆盖问题的可行解。利用分子信标模型来解决图的最小顶点覆盖问题,和其它DNA计算方法相比,该方法操作起来更加方便。 相似文献
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罗艳萍 《读与写:教育教学刊》2008,5(6)
The communication of people partially is the communication of cultures. Culture has a direct effect on international commercial activities in all aspects. Different conceptions about time, space, equality, law and the like, lead people to deal with things in different ways. So to know cultures of the counterpart is to facil-itate our enterprises so as to have a smooth and successful communication in commercial activity. 相似文献
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Richard Denner 《海外英语》2007,(4):14-15
Rosco and I wait for the fishermen to return.I sit at a wooden bench near the store at Mt.Baker Resort and watch the clouds change shape. Rosco has my belt around his neck and an eight foot tow chain hooked to a tree. Dogs must be on a leash. Ducks and rabbits are loose. 相似文献
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Given a graph G,a subgraph C is called a clique of G if C is a complete subgraph of G maximal under inclusion and |C|≥2. A clique-transversal set S of G is a set of vertices of G such that S meets all cliques of G. The clique-transversal number, denoted as TC (G), is the minimum cardinality of a clique-transversal set in G. The clique-graph of G, denoted as K (G), is the graph obtained by taking the cliques of G as vertices, and two vertices are adjacent if and only if the corresponding cliques in G have nonempty intersection. Let F be a class of graphs G such that F={G|K(G) is a tree}. In this paper the graphs in F having independent clique-transversal sets are shown and thus TC (G)/|G|≤1/2 for all G ∈ F. 相似文献
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《海外英语》2007,(5):10-11
Many college freshmen arrive woefully unprepared to do college work, and as disadvantaged populations continue to grow, the share of the American work force that has made it through college is expected to plummet. Many experts blame that educational failure not just on high schools but also on colleges. School & College, a special report by The Chronicle, looks at efforts to fix the system. What reforms would better prepare students for college? What should schools and colleges be doing differently? How should state and federal officials help? 相似文献
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陈美曦 《山东教育学院学报》2008,23(2):103-107
Different nations have different social cultures, and the social culture of every nation is developing with the development of the nation, language is greatly influenced by social culture, which enables language to possess national and historical characteristics. Word is the smallest, independent, meaningful linguistic unit of language. It can well reflect the national and historical characteristics. From synchronic aspect, the social and cultural influence on word meaning is mainly embodied in conceptual and associative meanings of word. The incorrespondence of word meaning is a phenomenon that exists in both conceptual and associative meanings of word among different languages. From diachronic aspect, the development of social culture causes some changes of word meaning to some extent. Therefore, social culture plays a key role in vocabulary learning and mastery of a language. 相似文献
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邱崇丙 《唐山师范学院学报》2014,(1):21-23
汉字的六书,《说文》对“转注”一类,语焉不详。后世学者提及转注,也仅限于许慎所举出的例字。《汉字例说》一文,作者从转注的角度综合考虑,对部分现代常用字作了分析,跟传统的解释有所不同。希望能抛砖引玉,互相切磋,以推进学术研究。 相似文献
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《海外英语》2007,(4):36
There are numbers of crossroads on our long and unpredictable life journey where we totally have no idea about which direction to choose. No matter what our decision is, we should not turn back, but face the music and go ahead instead. I am this kind of girl who always does try without regretting, one example is how I dealt with my love. 相似文献