共查询到20条相似文献，搜索用时 93 毫秒
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集成算法是机器学习领域的研究热点。随机子空间算法是集成算法的一个主要算法。随机子空间生成的特征子集可能含有冗余特征、甚至噪声特征,影响算法的分类精度。为此,提出了一种基于假设间隔的弱随机特征子空间生成算法(WRSSimba),有效去除了特征子集中冗余特征和噪声特征。在UCI数据集上的实验结果表明,WRSSimba的分类性能优于随机子空间算法和Simba算法。 相似文献
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为提高特征选择算法的分类精度,使特征子集尽快达到全局最优,提出了一种基于教与学优化算法的特征选择方法。该方法首先将最大相关最小冗余的过滤式特征选择算法融入其中,然后利用教与学优化算法对特征子集进行迭代寻优,构造一个混合式特征选择框架。经UCI数据集试验,证明了该算法的收敛速度与分类精度均优于其它算法。 相似文献
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常志玲 《洛阳师范学院学报》2011,30(5):74-77
应用粗糙集理论,提出了一种新的多变量决策树构造算法.该算法以核相对于决策类的泛化来划分样本集,如果所划分子集的样本存在不一致决策类并且未用于划分的属性为空时,试探着分别把该子集和一致性子集合并,计算各合并子集的条件类对决策类的确定性程度,选择确定性程度大的作为同一子集,并用一致性子集的类标号进行标示.和苗夺谦提出的多变量决策树算法比较,本算法充分考虑了训练集中的噪声数据,允许在构造决策树的过程中划入正域的实例类别存在一定的不一致性,可简化生成的决策树,提高决策树的泛化能力. 相似文献
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谐波检测是电力系统中无功补偿和谐波滤除等电能质量分析与控制的前提。本文结合四阶累积量和TAM算法,提出基于四阶累积量的TAM算法电力系统谐波检测。本文方法以信号空间为模型,首先用盖氏圆检测出信号源数,然后利用四阶累积量定义的矩阵代替传统二阶多信号分类法中的自相关矩阵做特征分解,将特征值对应的特征向量分为信号子空间和噪声子空间,再结合信号子空间和噪声子空间的正交性以及子空间的旋转不变性,估计出信号的频率。最后采用总体最小二乘法(TLS)计算得到信号的幅值。通过MATLAB软件仿真实验验证和实际电力系统数据分析表明该方法能有效地抑制高斯噪声,精确度高、抗噪性强,具有一定的应用价值。 相似文献
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支持向量机（SVM）在处理大样本特征维数较多的数据集时,算法消耗时间长而且容易陷入局部最优解,选择不合适的SVM算法参数会影响SVM模型分类性能。为了提高SVM性能,提出了基于粒子群算法（PSO）和遗传算法（GA）相结合的SVM特征选择与参数同步优化算法PGS。在UCI标准数据集上的实验表明,PGS算法能有效地找出合适的特征子集及SVM算法参数,提高收敛速度并能在较小的特征子集获得较高的分类准确率。 相似文献
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大数据时代,数据量呈现爆炸式增长,且在内容与形式上日益复杂化,造成数据质量下降、数据丢失等,即产生不完备数据。提出一种改进的C4.5算法,使其能更好地处理不完备数据。每次特征选择前对本次特征选择的数据子集使用子集匹配方法进行处理,通过比较数据清洗方法与子集匹配方法的结果,显示即便是在相同清洗规则下,子集匹配方法在算法分类准确率上也更有优势。实验结果证明,在利用C4.5算法进行特征选择时,在该数据子集上对不完备数据进行处理,可以得到较高的分类准确率,同时得到比数据清洗高的时间复杂度。 相似文献
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基于CNN的迁移模型用于铝型材表面瑕疵分类识别研究中，未考虑所提取的瑕疵特征图中冗余信息对分类性能的影响.针对该问题，提出了一种基于集成迁移学习的铝型材瑕疵分类方法，首先基于CNN的传统迁移模型自动获取铝型材瑕疵特征，再利用多尺度膨胀卷积对所提取的铝型材瑕疵特征进行稀疏采样，获取多组差异化的瑕疵特征，通过训练生成一组具有差异化的CNN分类器，并将其集成.实验结果证明，该方法相对于传统基于CNN的迁移模型，在铝型材瑕疵分类上，具有更高的分类准确率，性能更优. 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