26 resultados para SVM

em Chinese Academy of Sciences Institutional Repositories Grid Portal


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杜鹃属(Rhododendron L.)是中国种子植物中最大的属,其现代分布和分化中心是我国西南部的横断山区和东喜马拉雅地区。我国西部、西南部的云南、四川、西藏等地共有杜鹃达450种,仅特有种就有约300种。对杜鹃属分布的深入研究是横断山区生物多样性保护不可缺少的重要部分。 由于物种分布与环境因子之间存在着紧密的联系,利用环境因子作为预测物种分布模型的变量是当前最普遍的建模思路。但是绝大多数物种分布预测模型都遇到了难以解决的“高维小样本”问题――模型在标本数据不足时无法给出合理的预测,或者模型无法处理大量的环境变量。机器学习领域的理论和实践已经证明,基于结构风险最小化原理的支持向量机(Support Vector Machine, SVM)算法非常适合“高维小样本”的分类问题。为了探索其应用在物种分布预测问题上的可能性,本文创新性的实现了基于SVM算法的物种分布预测系统。然后,本文以30个杜鹃属(Rhododendron L.)物种为检验对象,利用其标本数据和11个1km的栅格环境变量图层作为模型变量,预测其在中国的潜在分布区。本文通过全面的模型评估——专家评估,ROC (Receiver Operator Characteristic)曲线和曲线下方面积AUC (Area Under the Curve)——来比较模型的性能。试验结果表明,我们所实现的以SVM为核心的物种分布预测系统无论在计算速度还是预测效果上都远远优于当前广泛使用的GARP (Genetic Algorithm for Rule-Set Prediction)预测系统。 之后,本文进一步探讨了SVM预测系统预测效果与环境变量维数和标本点个数的关系。试验结果表明,对于只有少量标本点的物种SVM的预测结果仍然具有相当的合理性。由此可见, SVM预测系统很好的解决了以前众多模型无法克服的稀有种和标本点稀少的物种的潜在分布区模拟问题。同时本文发现大的环境维数(高维)对于物种潜在分布区的预测有着决定性的作用,因此模型处理高维问题的能力显得至关重要。 最后,我们使用中国所有可获取的杜鹃属标本数据,以及83个1km的栅格环境变量图层,对400种杜鹃属物种的潜在分布区进行预测。根据预测出来的物种潜在分布区,我们得到了中国杜鹃属物种潜在多样性分布格局,特有物种潜在多样性分布格局,濒危杜物种潜在的分布格局,各亚属物种潜在分布格局,以及不同生活型物种潜在多样性分布格局。这些分布区图不仅可以对杜鹃属起源研究提供分析验证的条件,还能为其引种、保护和新种的搜寻提供有利的空间依据。

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This paper applies data coding thought, which based on the virtual information source modeling put forward by the author, to propose the image coding (compression) scheme based on neural network and SVM. This scheme is composed by "the image coding (compression) scheme based oil SVM" embedded "the lossless data compression scheme based oil neural network". The experiments show that the scheme has high compression ratio under the slightly damages condition, partly solve the contradiction which 'high fidelity' and 'high compression ratio' cannot unify in image coding system.

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First, the compression-awaited data are regarded Lis character strings which are produced by virtual information source mapping M. then the model of the virtual information source M is established by neural network and SVM. Last we construct a lossless data compression (coding) scheme based oil neural network and SVM with the model, an integer function and a SVM discriminant. The scheme differs from the old entropy coding (compressions) inwardly, and it can compress some data compressed by the old entropy coding.

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草图符号的自适应学习中,不同用户的训练样本数量可能不同。保持在不同样本数量下良好的学习效果成为需要解决的一个重要问题.提出一种自适应的草图符号识别方法,该方法采用与训练样本个数相关的分类器组合策略将模板匹配方法和SVM统计分类方法进行了高效组合.它通过利用支持小样本学习的模板匹配方法和支持大量样本学习的SVM方法,并同时利用草图符号中的在线信息和离线信息,实现了不同样本个数下自适应的符号学习和识别.基于该方法,文中设计并实现了支持自适应识别的草图符号组件.最后,利用扩展的PIBGToolkit开发出原型系统IdeaNote.评估表明,该方法可以在24类草图符号分别使用1到20个训练样本时具有较高的识别正确率和较好的时间性能.

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In this paper, a new classifier of speaker identification has been proposed, which is based on Biomimetic pattern recognition (BPR). Distinguished from traditional speaker recognition methods, such as DWT, HMM, GMM, SVM and so on, the proposed classifier is constructed by some finite sub-space which is reasonable covering of the points in high dimensional space according to distributing characteristic of speech feature points. It has been used in the system of speaker identification. Experiment results show that better effect could be obtained especially with lesser samples. Furthermore, the proposed classifier employs a much simpler modeling structure as compared to the GMM. In addition, the basic idea "cognition" of Biomimetic pattern recognition (BPR) results in no requirement of retraining the old system for enrolling new speakers.

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In this paper, a novel approach for mandarin speech emotion recognition, that is mandarin speech emotion recognition based on high dimensional geometry theory, is proposed. The human emotions are classified into 6 archetypal classes: fear, anger, happiness, sadness, surprise and disgust. According to the characteristics of these emotional speech signals, the amplitude, pitch frequency and formant are used as the feature parameters for speech emotion recognition. The new method called high dimensional geometry theory is applied for recognition. Compared with traditional GSVM model, the new method has some advantages. It is noted that this method has significant values for researches and applications henceforth.

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This paper describes the ground target detection, classification and sensor fusion problems in distributed fiber seismic sensor network. Compared with conventional piezoelectric seismic sensor used in UGS, fiber optic sensor has advantages of high sensitivity and resistance to electromagnetic disturbance. We have developed a fiber seismic sensor network for target detection and classification. However, ground target recognition based on seismic sensor is a very challenging problem because of the non-stationary characteristic of seismic signal and complicated real life application environment. To solve these difficulties, we study robust feature extraction and classification algorithms adapted to fiber sensor network. An united multi-feature (UMF) method is used. An adaptive threshold detection algorithm is proposed to minimize the false alarm rate. Three kinds of targets comprise personnel, wheeled vehicle and tracked vehicle are concerned in the system. The classification simulation result shows that the SVM classifier outperforms the GMM and BPNN. The sensor fusion method based on D-S evidence theory is discussed to fully utilize information of fiber sensor array and improve overall performance of the system. A field experiment is organized to test the performance of fiber sensor network and gather real signal of targets for classification testing.

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Automatic molecular classification of cancer based on DNA microarray has many advantages over conventional classification based on morphological appearance of the tumor. Using artificial neural networks is a general approach for automatic classification. In this paper, Direction-Basis-Function neuron and Priority-Ordered algorithm are applied to neural networks. And the leukemia gene expression dataset is used as an example to testify the classifier. The result of our method is compared to that of SVM. It shows that our method makes a better performance than SVM.

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在过去的二十年中,数据挖掘和机器学习受到了越来越多的关注。 这很大程度上是因为在互联网时代信息传播和积累的速度越来越快, 人工处理数据越来越困难,智能化及自动化的数据处理能力成为迫切的需求。 为此人们设计了很多学习算法,希望计算机能具有人类的学习能力,即只要训练一次,就 可以自动处理数据。 尽管这种学习能力已经在很多成功的应用中得到了验证,但它建立在一个重要的假设基础上,即训练数据与目标数据的一致性。 这意味着:根据训练数据得到的模型只适用于具有同样分布的目标数据。如果需要完成一个新的任务, 即使是与原任务非常相近的任务,原来训练好的模型也可能会失效。但是如果重新提供训练数据必将付出很高的成本。 因为两个任务之间存在的相似性,在新任务的训练过程中彻底丢弃原有的训练数据也是非常不合理的。 考虑到数据来源的差异性和训练数据的时效性在实际应用中普遍存在,有必要寻找更有效的解决途径。 迁移学习的提出正是为了解决上面的问题。传统的学习过程实际上是实现了从人到机器的知识迁移。 迁移学习则是研究从一个学习任务到另一个学习任务的知识迁移,以提高知识利用的效率。 这样的知识迁移将在缺乏训练数据和训练数据时效较短的情况下 大大降低学习的成本并提高学习的效率和自动化程度。 本文从跨数据域迁移学习入手,研究无监督迁移学习技术,以及在数据流环境下的有监督迁移学习技术, 在以下三个方面做出了创新性贡献: 在迁移学习中首次提出利用最大间隔方法在没有目标数据域的训练数据的情况下完成分类任务。 提出了两种算法,以迭代优化技术为基础,分别在函数层以及参数层实现了辅助任务到目标任务的知识迁移。 在多个公开的数据集中的实验表明,两种算法的分类准确率均优于现有的迁移学习算法。 在数据流分类任务中,针对概念漂移问题首次提出对概念漂移进行建模,来设计一种 可以自动适应数据分布变化的动态分类器。作为一种新的分类框架,可用于logistic regression和SVM等诸多分类模型。在实验中表明,所提出的算法有效避免了传统滑动 窗口方法导致的数据过拟合,实现了较高的分类准确率。 提出在具有多个节点的传感器网络中进行异常检测的新方法。利用主成分分析对数据空间进行变换,并根据能量阈值 对数据空间进行划分,构建异常子空间, 根据数据在异常子空间上的投影来检测异常数据点。基于数据点在异常子空间上的投影信息还可以进一步对异常来源 进行定位,并度量异常的大小。在实验中所提出的方法展现了较强的异常检测能力。

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软件缺陷对于软件质量以及软件项目的成本等都有非常重要的影响。软件缺陷预测技术从20世纪70年代发展至今,一直是软件工程领域最活跃的内容之一,在分析软件质量、控制软件成本方面起着重要的作用。软件缺陷预测技术分为静态和动态两种,其中基于软件度量元的静态缺陷预测技术是现今比较成熟且应用比较广泛的技术,它通过对缺陷相关的软件产品,例如代码,进行度量元的提取和计算,建立预测的模型以预测后期可能引入的缺陷。随着数据挖掘技术的成熟,越来越多的静态缺陷预测方法开始对软件项目历史数据进行分析和建模,挖掘这些历史数据以预测缺陷被证明是更加精确和可靠的。 但是,现有缺陷预测技术大都需要对软件的设计、代码或者测试等相关的活动进行分析,无法在软件生命周期的早期活动,例如需求活动,通过预测这些活动引起的潜在的缺陷的分布、类型和规模,从而为软件过程的后续活动提供早期预警以及有意义的依据和参考。本文提出了一种基于需求变更的软件缺陷预测方法,这种方法以迭代开发的升级性项目为应用对象,使用信息检索和数据挖掘相关技术,分析和处理升级项目中的历史需求文档和缺陷记录数据,建立支持向量机(SVM)分类预测模型,从而对后续版本的需求变更可能引入的缺陷进行预测。 本文深入细致的研究了现有的缺陷预测技术,分析并对比了这些技术的应用范围、特点和局限性,在此基础上提出了一种新的基于需求变更的软件缺陷预测方法。本方法使用信息检索技术关联匹配软件项目历史需求和历史缺陷,并根据历史需求所关联的缺陷分布属性将这些需求分类,之后对需求进行特征即度量元的提取和计算,从而建立SVM分类模型。当新的需求变更发生时可以使用建立的模型预测其分类,以此预测可能引入的缺陷。本文还介绍了基于需求变更的缺陷预测系统的核心功能设计与实现,并在最后通过使用一个实际的商业软件项目数据集对方法和系统进行了验证。在实验中预测系统表现了较高的精确度,可以提供较为可靠的缺陷预测结果,这些预测结果可以为软件项目中需求开发提供有效的变更影响分析,为控制软件成本和项目风险提供有效的决策支持。

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本文主要研究连续语音中单词音节的神经网络建模问题.采用了一种富有特色的特征提取方法,并依据高维空间点覆盖理论,对实际连续数字语音的各不同数字音节,以人工切自连续数字语音中的2640个单字音节,构建连续语音中各不同数字音节的特征空间覆盖区,并使用7308个自连续数字语音中切分出的单字音节,利用仿生模式识别原理,进行了建模正确性验证.验证结果正确率达到97%以上,对同样数量的少量建模样本,识别率优于SVM方法.

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本文实现了一种基于仿生模式识别的人脸识别系统,并将其识别效果同最近邻分类器与不同核函数的SVM进行了分析比较.以ORL人脸库为识别对象,针对有"拒识"的情况下,通过改变不同识别算法的可调参数,在保证参与训练人的正确识别率在大致相同水平的条件下,分析了参与训练人的错误识别率(错识别为参与训练的其他人)与未参与训练人的错误接受率(错识别为参与训练的某人)的优劣.比较结果表明,基于仿生模式识别的方法明显优于其它模式识别方法.

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A new theoretical model of Pattern Recognition principles was proposed, which is based on "matter cognition" instead of "matter classification" in traditional statistical Pattern Recognition. This new model is closer to the function of human being, rather than traditional statistical Pattern Recognition using "optimal separating" as its main principle. So the new model of Pattern Recognition is called the Biomimetic Pattern Recognition (BPR)(1). Its mathematical basis is placed on topological analysis of the sample set in the high dimensional feature space. Therefore, it is also called the Topological Pattern Recognition (TPR). The fundamental idea of this model is based on the fact of the continuity in the feature space of any one of the certain kinds of samples. We experimented with the Biomimetic Pattern Recognition (BPR) by using artificial neural networks, which act through covering the high dimensional geometrical distribution of the sample set in the feature space. Onmidirectionally cognitive tests were done on various kinds of animal and vehicle models of rather similar shapes. For the total 8800 tests, the correct recognition rate is 99.87%. The rejection rate is 0.13% and on the condition of zero error rates, the correct rate of BPR was much better than that of RBF-SVM.