改进的鲁棒稀疏双支持向量回归:线性规划方法

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本文献主要探讨了《基于线性规划的改进鲁棒和稀疏双支持向量回归》(An Improved Robust and Sparse Twin Support Vector Regression via Linear Programming),发表于2014年的《SoftComput》期刊,第18卷第2335-2348页,DOI:10.1007/s00500-014-1342-5。作者是Xiaobo Chen、Jian Yang 和 Long Chen,该研究于2014年6月24日在线发布,由Springer-Verlag Berlin Heidelberg出版。 TSVR(Twin Support Vector Regression)是一种相对较新的回归方法,它试图通过解决两个相关的支持向量机(SVM)类型问题,找到一对非平行平面,即提供ε不敏感的上界和下界。尽管TSVR在性能上优于传统的支持向量回归(SVR)等方法,但它存在几个关键问题: 1. **缺乏模型复杂度控制**:TSVR在寻找最优解时可能过于复杂,导致过拟合,产生非最优解决方案。这限制了其在实际应用中的泛化能力。 2. **二次编程问题复杂性高**:TSVR涉及到解决两个相关的二次规划问题,这在实现上较为复杂,增加了算法的执行难度。 3. **对异常值敏感**:由于其设计,TSVR对于数据集中的异常值非常敏感,这可能导致预测结果受噪声影响,降低模型的稳健性。 4. **解决方案不稀疏**:TSVR的求解过程通常不会自然产生稀疏解,这可能不是某些应用场景(如需要低维度表示或减小计算负担)所需的特性。 针对这些问题,作者提出了一种新的回归算法,即鲁棒和稀疏双支持向量回归(Robust and Sparse Twin Support Vector Regression)。核心思想在于将TSVR转化为一个凸优化问题,通过引入正则化技术进行改进。通过这种方法,他们试图解决模型复杂度过高的问题,并通过线性规划技术来简化原本的二次规划求解过程,提高算法的实施效率。 引入正则化有助于控制模型复杂度,防止过拟合,同时使得求解过程更加高效。线性规划的使用意味着解决方案将更易于理解和计算,减少了对异常值的敏感性,提高了模型的稳健性。此外,通过正则化的手段,作者还试图在保持良好预测性能的同时,促使模型的系数变得稀疏,从而在保持模型精度的同时降低了存储和计算成本。 这篇文章的主要贡献是提出了一种新颖的回归算法,旨在克服TSVR的局限性,通过结合线性规划和正则化技术,提供了一个在鲁棒性、模型复杂度控制和稀疏性方面有所改进的双支持向量回归框架。这对于处理大规模数据集、需要稳定预测并且寻求低维表示的应用具有潜在的实际价值。

Shifts in China’s Rural and Urban Population: 2000-2020 The bar chart clearly reveals that from 2000 to 2020, while the total population in China increased moderately from 1.25 billion to 1.41 billion, population in urban and rural areas experienced dramatic shifts in different directions. Urban population rose from 450 million in 2000 to 670 million in 2010 and 900 million in 2020; contrastingly, rural population declined from 800 million in 2000 to 680 million in 2010 and 510 million in 2020. The population gap narrowed largely because of the joint effects of urbanization, unequal economic opportunities in rural and urban areas, and the expansion of higher education. In the first place, there was a large-scale urban sprawl during this period. Places which had been part of the vast countryside were incorporated into cities, causing hundreds of millions of rural dwellers to be passively transformed into urban residents. What’s more, while urban living standards improved greatly in these years, few economic opportunities fell on rural areas and most peasant families remained at the poverty line. Poverty prompted the call for change, leading a large quantity of healthy young peasants to leave their hometowns and flock to cities for a better living. Last but not least, China’s higher education grew at an unprecedented rate in these years. More high school graduates than ever before entered colleges and universities, most of whom preferred to stay in urban areas after graduation for personal development. The increase in urban population was a sure indication of economic and educational achievements in China. It benefited the country in many aspects, relieving the shortage of labor force in cities, lessening the burden of peasants to support their families, and affording young people from rural areas more opportunities to display their talents. However, the migration of rural residents into urban areas inevitably brought about disadvantages. Some of them, such as waste of arable land and left-behind children in the countryside, as well as traffic congestion and soaring housing prices in cities, have already called the attention of the government and corresponding measures have begun to take effect. But others, especially the inability of many peasants to integrate into urban life due to their lack of education and civilized habits, have long been neglected. In this sense, we cannot be satisfied with the superficially optimistic figures in the chart, but should endeavor to foster the integration of these newcomers by providing them with adequate assistance in educational and cultural aspects, so that they can find easier access to the prosperity and convenience of urban life and be more fully devoted to the development of cities.翻译成英文版两百单词左右的文章

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