共查询到20条相似文献，搜索用时 62 毫秒
1.
刘林东 《广东教育学院学报》2010,30(3):75-79
给出智能组卷数据模型,采用遗传算法中编码、初始群体、迭代等步骤,利用交叉概率、变异概率和适合度判断迭代的收敛性,并产生适合规则的群体.对比遗传算法及其他组卷策略,遗传算法在组卷次数及组卷时间上优于传统的组卷策略. 相似文献
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针对传统基于简单遗传算法的组卷系统收敛速度慢,组卷质量较差等缺陷,设计一种基于改进小生境遗传算法的自适应组卷系统。首先依照组卷约束权重比,生成适应度值较高的初始种群．其次对选择策略进行优化。引入小生境预选机制以维持种群多样性,防止过早收敛。再次根据组卷特点改进交叉算子和变异算子,根据种群进化情况,自动调整交叉概率和变异概率。最后经过若干迭代后达到终止条件,以自适应方式生成目标试卷。实验结果证明,与简单遗传算法相比,改进的遗传算法在收敛速度和组卷质量上均有显著的提高。 相似文献
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在在线考试自动组卷中,为了避免简单遗传算法收敛速度慢及早熟收敛的问题,提出了基于实数编码、分段交叉、有条件生成初始种群的改进遗传算法。实践表明,改进的遗传算法能更好地解决自动组卷问题,具有较好的实用性。 相似文献
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张清富 《广东广播电视大学学报》2009,18(5):101-105
为克服经典遗传算法求解智能组卷时存在的盲目搜索、收敛速度慢和个体易“早熟“等缺点,文章提出了基于动态自适应技术遗传算法。利用求解问题的特征改进经典遗传算法的多个关键部分,采用动态自适应技术,提高算法的寻优速度。实验结果表明,采用改进式的自适应遗传算法实现的组卷策略具有收敛速度快、搜索精度高、鲁棒性强等特点,具有很好的性能与实用性。 相似文献
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时小虎 《甘肃广播电视大学学报》2012,22(3):34-37
在深入分析自动组卷问题的基础上,比较了几种常用组卷算法的优缺点,提出了分组四维编码的改进自适应遗传算法。该算法的编码方案为分组四维编码,使用模拟正态分布的分组轮盘赌选择算子进行种群选取,对交叉和变异算子的概率,根据个体的适应度值分布特点进行非线性自适应调整。实验结果表明,改进后的遗传算法很好地实现了组卷功能,在效率和质量上都明显优于传统遗传算法组卷,具有很好的实用性。 相似文献
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高效率的组卷功能的实现依赖于高效的组卷算法,很多学者都对组卷算法做了多方面的研究与改进．目前对遗传算法的研究应用是最近智能组卷系统中比较广泛的算法应用．本文是对基本遗传算法在智能组卷领域的改进研究,以实现高效智能组卷． 相似文献
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提出了对遗传算法中适应度函数的构造,数据的编码等问题的改进方案,通过对"早熟"问题的分析,将改进的自适应交叉概率Pc和变异概率Pm算法应用到遗传算法中。最后给出了一种基于遗传算法的关联规则挖掘算法,并应用一个实例验证了算法的有效性。 相似文献
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将遗传算法用于电力系统无功优化,并对传统遗传算法的编码方式、遗传操作算子、交叉和变异概率以及迭代终止判据等方面进行了改进,同时使用本文的算法对IEEE6及IEEE14节点系统进行了无功优化计算,结果表明改进后的遗传算法合理可行。 相似文献
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遗传算法属于进化算法(EvolutionaryAlgorithms)的一种,它通过模仿自然界的选择与遗传机理来寻找最优解。遗传算法具有与问题领域无关且快速随机的搜索能力,搜索从群体出发,具有潜在的并行性,可以进行多个个体的同时比较,搜索使用评价函数启发,过程简单,使用概率机制进行迭代,具有随机性,具有可扩展性,容易与其它算法结合。基本01背包问题,提出遗传问题解决的关键技术,设计评价函数和遗传算子,并通过散播变异、移位变异、插入变异改进01背包问题中的遗传算法,很好地解决了遗传问题。 相似文献
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随着计算机的日益普及和互联网技术的进步,计算机辅助网考在大学英语等级考试中越来越普遍.基于目前大学英语网考组卷过程中存在的组卷问题,分析设计了智能组卷数学模型,以定量的形式表征组卷过程,结合组卷的数学模型以及相应的约束条件引入改进遗传算法,设计智能组卷算法,形成一套基于大学英语网考的智能组卷方法.通过仿真结果分析,该智能组卷方法通过优化迭代,可以快速组合理想试卷,所设计的智能组卷算法不仅组卷质量好,速度也快,很好地反映了学生的真实英语水平. 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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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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《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
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Migration occurs behind a variety of reasons and has a great effect on the whole world. People may migrate in order to improve their economic situation, or in order to escape civil strife, persecution, and environmental disasters. The impact of migration is complex, bringing both benefits anddisadvantages. This paper briefly talks about the causes of migration, the allocation of benefits, and the ways in which individual countries and the international community deal with this important subject. 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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Sister Carrie is one of the most controversial characters in American literature.Thought as a "fallen woman" firstly,she was defined as a "new woman" by some critics later. However, by digging into the motivaton behind the whole process of Carrie's "success", the relationship between Carrie and her creator (the author), the social conditions of then American, it can be found that Carrie has never been free-standing on her thought and she has never found her real-sdf even after becoming a famous actress. In a society dominated by mass consumerism Carrie is only an adherent of her own desires. She also is a representative of all those country girls flooded into cities, a symbol and a sacrifice of the urbanization of America in a time countryside was overcome by cities. 相似文献