共查询到18条相似文献,搜索用时 78 毫秒
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介绍了广义粗糙集模型和Ziarko变精度粗糙集模型,找出了它们的不足;借助引入的误差参数β(0≤β<0.5),给出了基于后继邻域的一般二元关系下变精度粗糙集模型的β上近似、β下近似、3边界和β负域的定义以及β近似质量和β粗糙性测度定义;详细讨论了β上、下近似算子的性质、该模型与其他粗糙集模型的关系以及一般二元关系下两种变精度粗糙集模型的关系;最后,举例说明了该模型在信息处理中的应用。 相似文献
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在模糊近似空间中,结合直觉模糊集的隶属度、非隶属度与模糊蕴涵算子,提出基于θ算子和θ算子的直觉模糊集及其隶属度和非隶属度的概念,并证明它们一系列性质.然后,结合直觉模糊集与变精度粗糙集,定义基于θ算子的变精度直觉模糊粗糙集,提出求解变精度粗糙集阈值参数β的方法,使用算例分析该方法. 相似文献
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介绍了Ziarko’s变精度粗糙集模型和粗糙模糊集模型,找出了它们的不足。基于支集相对错误分类率及误差参数β(0≤β<0.5),提出了变精度粗糙模糊集模型,讨论了模型中β上、下近似算子的性质;分析了该模型与Ziarko’s变精度粗糙集模型和粗糙模糊集模型的关系;最后给出了该模型中近似约简的定义和方法,并通过实例分析说明了约简算法的有效性。 相似文献
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对Bayesian粗糙集模型的讨论 总被引:1,自引:0,他引:1
变精度粗糙集模型是对传统的(Pawlak)粗糙集模型的一个重要拓展,但变精度模型中需要设定人为参数不利于信息的客观体现。Bayesian粗糙集模型是基于变精度和概率论的思想最新提出的无参数模型。对Bayesian粗糙集模型进行了分析,指出了其中的不足,提出了一种改进形式。 相似文献
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Attribute reduction with variable precision rough sets (VPRS) attempts to select the most information-rich attributes from a dataset by incorporating a controlled degree of misclassification into approximations of rough sets. However, the existing attribute reduction algorithms with VPRS have no incremental mechanisms of handling dynamic datasets with increasing samples, so that they are computationally time-consuming for such datasets. Therefore, this paper presents an incremental algorithm for attribute reduction with VPRS, in order to address the time complexity of current algorithms. First, two Boolean row vectors are introduced to characterize the discernibility matrix and reduct in VPRS. Then, an incremental manner is employed to update minimal elements in the discernibility matrix at the arrival of an incremental sample. Based on this, a deep insight into the attribute reduction process is gained to reveal which attributes to be added into and/or deleted from a current reduct, and our incremental algorithm is designed by this adoption of the attribute reduction process. Finally, experimental comparisons validate the effectiveness of our proposed incremental algorithm. 相似文献
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A variable precision rough set approach to the remote sensing land use/cover classification 总被引:2,自引:0,他引:2
Xin Pan Shuqing Zhang Huaiqing Zhang Xiaodong Na Xiaofeng Li 《Computers & Geosciences》2010,36(12):1466-1473
Nowadays the rough set method is receiving increasing attention in remote sensing classification although one of the major drawbacks of the method is that it is too sensitive to the spectral confusion between-class and spectral variation within-class. In this paper, a novel remote sensing classification approach based on variable precision rough sets (VPRS) is proposed by relaxing subset operators through the inclusion error β. The remote sensing classification algorithm based on VPRS includes three steps: (1) spectral and textural information (or other input data) discretization, (2) feature selection, and (3) classification rule extraction. The new method proposed here is tested with Landsat-5 TM data. The experiment shows that admitting various inclusion errors β, can improve classification performance including feature selection and generalization ability. The inclusion of β also prevents the overfitting to the training data. With the inclusion of β, higher classification accuracy is obtained. When β=0 (i.e., the original rough set based classifier), overfitting to the training data occurs, with the overall accuracy=0.6778 and unrecognizable percentage=12%. When β=0.07, the highest classification performance is reached with overall accuracy and unrecognizable percentage up to 0.8873% and 2.6%, respectively. 相似文献
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于秀清 《计算机工程与应用》2010,46(19):55-57
在函数粗集的基础上给出了下近似积分、上近似积分与粗积分的概念,利用这些概念不仅给出了粗积分的可分辨关系、不可分辨关系、有限萎缩性和有限扩张性定理,还定义了函数粗集的精度与粗糙度及二者之间的一些关系,并给出函数粗集的筛选-剩余原则。 相似文献
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基于优势关系的变精度粗糙集模型将传统粗糙集中的等价关系扩展为优势关系,并结合变精度的思想来定义相关概念,从而可以处理具有偏好关系的信息并具有一定的容错能力。然而,传统优势关系的定义仍然过于严格,只有当一个对象x的每个属性值都优于另一个对象y时,该对象x才优于y。当属性个数较多时,这种优势关系的定义会导致对象的优势集偏小,影响到规则的提取和决策结果。为了解决这一问题,通过引入参数的方法扩展了传统优势关系的定义,并在此基础上进一步给出了扩展后的优势集和近似集的概念,建立了扩展优势关系下的变精度粗糙集模型,采用覆盖率和测试精度作为模型的评估指标。最后给出算例,并在UCI数据集上进行大量的实验将所提模型与传统优势关系下的变精度粗糙集模型进行比较。 相似文献