基于子空间选择的SVM快速算法及其在医学图像奇异点检测中的应用

支持向量机（SVM）花费大量时间用于对非支持向量样本的优化．根据支持向量都是位于两类边界的靠近分类超平面的样本点，本文提出首先利用基于中心距离比值法排除大部分远离分类超平面的样本，然后以最小类间距离样本数作为测度进一步选择边界样本．得到包含所有支持向量的最小样本集，构成新的训练样本集训练SVM．将提出的算法应用于解决医学图像奇异点检测问题．实验结果表明．该算法减小了训练样本集的规模，有效地缩短了SVM训练算法的时间．同时获得了较高的榆出率．     

代价敏感的直推式支持向量机算法

针对不均衡数据集下分类超平面偏移导致直推式支持向量机样本标记准确率低的问题,结合动态代价和TSVM算法,提出一种代价敏感的TSVM算法,该算法依据类样本的空间分布信息计算类错分代价,利用KKT条件选择对当前分类超平面有影响的样本加入下一轮迭代,该算法可以提高初始分类器的分类性能,减少错误的传递和累积,从而提高标注准确率,增强最后分类器的泛化性能.最后在UCI数据集上的实验结果表明该算法在不均衡数据集下的有效性.     

改进的主动学习算法及在高光谱分类中的应用

针对主动学习算法能主动从大量未标记样本中选择最能提高分类器性能的样本加入训练集,可从小的非最优训练集建立高性能的分类器这一特点,以及传统主动学习算法熵值装袋查询的多值偏置问题,提出了改进的均值熵值装袋查询算法,引入权值函数保证了取样的多样性.通过对高光谱遥感图像分类的实验表明:主动学习只需大约20%的样本即可达到使用全部数据集作为训练集的分类效果,而且均值熵值装袋查询方法具有较高的分类精度,同时拥有较快的收敛速度.     

一种新的支持向量分类算法ACNN-SVM

针对NN-SVM算法的不足,提出了一种新的支持向量分类算法--ACNN-SVM.先对训练样本集进行最近邻修剪,用SVM训练得到一个SVM模型,然后,计算最近邻修剪后的训练样本集中样本到超平面的距离,如果距离差大于给定的阈值则将其从最近邻修剪后的训练样本集中删除,最后对冉修剪后的样本集用SVM训练得到一个最终的SVM模型.实验表明,ACNN-SVM算法的效果优于NN-SVM算法.     

基于局部敏感哈希的K邻近算法识别垃圾短信

针对目前垃圾短信的识别算法存在的关键字及频次的规则死板,易于被不法分子探测和规避等问题,提出将局部敏感哈希的K邻近算法应用于垃圾短信分类识别;首先定义特征,然后采用局部敏感哈希算法计算向量距离,通过得到的距离衡量矩阵的相似性,量化矩阵相似程度,对本文中提出的优化模型进行实现和训练;基于短信文本内容,运用词频-逆向文本频率算法生成矩阵,利用局部敏感哈希算法求解最相似样本,记录样本类别,将训练结果导入K邻近算法分类器得到最优近邻,在测试集或验证集上对优化模型垃圾短信分类识别准确率进行评测。结果表明,经过K邻近算法分类器后,优化模型垃圾短信分类识别准确率达到98.7%。     

基于协同增量支持向量机的网络入侵检测

针对网络行为数据的不均衡、数量大、更新快的问题,结合均衡化、增量学习、分类器集成思想提出一种用于网络入侵检测的协同增量支持向量机算法,该算法利用多个分类器的协同工作,提高算法速度,每个子分类器依据类样本的空间分布计算类样本错分代价,避免分类超平面偏移,对多个子分类器进行加权集成获得最终分类器,提高最终分类器在不均衡数据集下的分类性能.最后,在KDDCUP1999数据集上的仿真实验结果表明,该算法对整体准确率、少数类及未知攻击都有较高的检测准确率.     

基于密度峰值聚类和模糊支持度的boosting随机森林

为了解决传统分类算法在不平衡样本集上分类效果不佳的问题,提出一种新的欠采样boosting集成算法(FECBoost).首先,通过改进的模糊熵反映样本集原始分布的不确定性,并用此模糊熵判断多数类样本所在的区域,称为安全区域或边界区域;其次,利用密度峰值聚类算法选取安全区域的代表性样本以减少分类器的训练时间和样本间的重叠,降低样本的不平衡度,实现静态欠采样;最后,训练新的boosting集成分类器,在算法每一次迭代之前,基于模糊熵和模糊支持度对多数类样本再次欠采样,使用于训练的样本集达到平衡.该动态欠采样依赖于分类器的训练过程,充分考虑了样本分布的不确定性和错分可能性.通过在真实样本集上的仿真实验验证了提出方法的有效性.     

逃避攻击下恶意PDF文件检测技术

KNN(K近邻)算法以其操作简单、分类效果明显的优点被广泛应用于网络入侵检测、垃圾邮件识别和图像识别等领域。KNN算法通过计算测试集与训练集之间的相似度进行分类。传统的机器学习分类模型通常只考虑分类的精度,没有考虑到攻击者的攻击问题,导致当存在非法攻击时,分类模型的鲁棒性降低。对此首先通过使用逃避攻击方法实现对KNN算法在恶意PDF文件分类上的攻击,然后将攻击产生的对抗样本添加到训练集中训练出新的分类器,最后模拟两种不同攻击方式在不同攻击强度下对改进前后KNN分类器分类效果的影响。实验结果表明,通过将对抗样本添加到训练集中能够有效提高KNN分类器的鲁棒性。     

面向不均衡小样本训练集的改进Boosting算法

传统的Boosting算法训练出的分类器常会出现过拟合和向多数类偏移.为此,提出一种基于自适应样本注入和特征置换的Boosting学习算法,通过在训练过程中加入人工合成样本,逐渐平衡训练集,并通过合成的样本对分类器学习进行扰动,使分类器选择更多有效的特征,提高了分类器的泛化能力.最后,在两类和多类图片分类问题上对该算法的有效性进行了考察,实验结果表明,该算法能够在样本数很少,且正负样本数量极不均衡的情况下,有效提高booting算法的泛化能力.     

SVM的快速分类及其算法

针对支持向量机中当样本集训练规模很大且存在野点时,其分类速度慢且精度不高的问题,提出一个支持向量机快速算法。其基本步骤是首先求取每类样本点的壳向量和中心向量,然后将求出的壳向量和中心向量合在一起,组成新的训练集进行训练,得到最终的分类器。实验表明采用这种学习策略,不仅大幅度降低了学习代价,而且获得的分类精度与直接通过大规模样本集训练得到的分类器的分类精度相当,同时分类速度也得到大幅度提高。     

Markedness and its Interpretation in Language Use

Language markedness is a common phenomenon in languages, and is reflected from hearing, vision and sense, i.e. the variation in the three aspects such as phonology, morphology and semantics. This paper focuses on the interpretation of markedness in language use following the three perspectives, i.e. pragmatic interpretation, psychological interpretation and cognitive interpretation, with an aim to define the function of markedness.     

Lower Paleozoic oil relationships within Williston Basin, Canada

The Williston Basin is a significant petroleum province, containing oil production zones that include the Middle Cambrian to Lower Ordovician, Upper Ordovician, Middle Devonian, Upper Devonian and Mississippian and within the Jurassic and Cretaceous. The oils of the Williston Basin exhibit a wide range of geochemical characteristics defined as "oil families", although the geochemical signature of the Cambrian Deadwood Formation and Lower Ordovician Winnipeg reservoired oils does not match any "oil family". Despite their close stratigraphic proximity, it is evident that the oils of the Lower Palaeozoic within the Williston Basin are distinct. This suggests the presence of a new "oil family" within the Williston Basin. Diagnostic geochemical signatures occur in the gasoline range chromatograms, within saturate fraction gas chromatograms and biomarker fingerprints. However, some of the established criteria and cross-plots that are currently used to segregate oils into distinct genetic families within the basin do not always meet with success, particularly when applied to the Lower Palaeozoic oils of the Deadwood and Winnipeg Formation.     

An Analysis of Catherine＇s Character——Wuthering Heights

Wuthering Heights, Emily Bronte＇s only novel, was published in December of 1847 under the pseudonym Ellis Bell. The book did not gain immediate success, but it is now thought one of the finest novels in the English language. Catherine is the key character of this masterpiece, because everybody and everything center on her though she had a short life. We can understand this masterpiece better if we know Catherine well.     

Characterization of Ordovician carbonate reservoirs, southeastern Saskatchewan, Canada

The discovery of the prolific Ordovician Red River reservoirs in 1995 in southeastern Saskatchewan was the catalyst for extensive exploration activity which resulted in the discovery of more than 15 new Red River pools. The best yields of Red River production to date have been from dolomite reservoirs. Understanding the processes of dolomitization is, therefore, crucial for the prediction of the connectivity, spatial distribution and heterogeneity of dolomite reservoirs.The Red River reservoirs in the Midale area consist of 3～4 thin dolomitized zones, with a total thickness of about 20 m, which occur at the top of the Yeoman Formation. Two types of replacement dolomite were recognized in the Red River reservoir: dolomitized burrow infills and dolomitized host matrix. The spatial distribution of dolomite suggests that burrowing organisms played an important role in facilitating the fluid flow in the backfilled sediments. This resulted in penecontemporaneous dolomitization of burrow infills by normal seawater. The dolomite in the host matrix is interpreted as having occurred at shallow burial by evaporitic seawater during precipitation of Lake Almar anhydrite that immediately overlies the Yeoman Formation. However, the low δ18O values of dolomited burrow infills (-5.9‰～ -7.8‰, PDB) and matrix dolomites (-6.6‰～ -8.1‰, avg. -7.4‰ PDB) compared to the estimated values for the late Ordovician marine dolomite could be attributed to modification and alteration of dolomite at higher temperatures during deeper burial, which could also be responsible for its 87Sr/86Sr ratios (0.7084～0.7088) that are higher than suggested for the late Ordovician seawaters (0.7078～0.7080). The trace amounts of saddle dolomite cement in the Red River carbonates are probably related to "cannibalization" of earlier replacement dolomite during the chemical compaction.     

Features of Women's language

Language is a means of verbal communication. People use language to communicate with each other. In the society, no two speakers are exactly alike in the way of speaking. Some differences are due to age, gender, statue and personality. Above all, gender is one of the obvious reasons. The writer of this paper tries to describe the features of women＇s language from these perspectives： pronunciation, intonation, diction, subjects, grammar and discourse. From the discussion of the features of women＇s language, more attention should be paid to language use in social context. What＇s more, the linguistic phenomena in a speaking community can be understood more thoroughly.     

Design and analysis of generic LBS application developing platform

Location based services is promising due to its novel working style and contents.A software platform is proposed to provide application programs of typical location based services and support new applications developing efficiently. The analysis shows that this scheme is easy implemented, low cost and adapt to all kinds of mobile nework system.     

橡胶颗粒沥青混合料低温抗裂性试验研究

以AC-13级配为基础,将橡胶颗粒代替部分集料掺入混合料中,以低温弯曲试验为评价方法对不同橡胶颗粒掺量下沥青混合料的低温抗裂性进行研究,并引入应变能密度值对混合料的低温抗裂性进行综合评价.试验结果表明:橡胶颗粒沥青混合料试件的破坏微应变均超过2 300,满足冬寒区的技术指标;无论是否掺加橡胶颗粒,随着温度的下降,沥青混合料破坏时的最大弯拉强度增大,弯拉应变降低,劲度模量增大;弯曲应变能密度在胶粒掺量为1%左右时具有较大的弯曲应变能密度值,此时橡胶颗粒沥青混合料具有较好的低温抗裂性.     

A computer generator for randomly layered structures

AcomputergeneratorforrandomlylayeredstructuresYUJia shun1,2,HEZhen hua2(1.TheInstituteofGeologicalandNuclearSciences,NewZealand;2.StateKeyLaboratoryofOilandGasReservoirGeologyandExploitation,ChengduUniversityofTechnology,China)Abstract:Analgorithmisintrod…     

低渗透非均质砂岩油藏启动压力梯度研究

理论推导与室内实验相结合,建立了低渗透非均质砂岩油藏启动压力梯度确定方法。首先借助油藏流场与电场相似的原理,推导了非均质砂岩油藏启动压力梯度计算公式。其次基于稳定流实验方法,建立了非均质砂岩油藏启动压力梯度测试方法。结果表明:低渗透非均质砂岩油藏的启动压力梯度确定遵循两个等效原则。平面非均质油藏的启动压力梯度等于各级渗透率段的启动压力梯度关于长度的加权平均;纵向非均质油藏的启动压力梯度等于各渗透率层的启动压力梯度关于渗透率与渗流面积乘积的加权平均。研究成果可用于有效指导低渗透非均质砂岩油藏的合理井距确定,促进该类油藏的高效开发。     

On Tragic Consciousness In The Works By Ernest Hemingway

As an American modern novelist who were famous in the literary world, Hemingway was not a person who always followed the trend but a sharp observer. At the same time, he was a tragedy maestro, he paid great attention on existence, fate and end-result. The dramatis personae's tragedy of his works was an extreme limit by all means tragedy on the meaning of fearless challenge that failed. The beauty of tragedy was not produced on the destruction of life, but now this kind of value was in the impact activity. They performed for the reader about the tragedy on challenging for the limit and the death.