基于贝叶斯决策树的交通事件持续时间预测

采用基于贝叶斯方法的决策树算法,利用上海市中心城区1536个交通事件持续时间数据,建立交通事件持续时间的预测模型.结果表明,事件类型是决策树中的第一层测试属性,不同类型事件的特性属性在决策树中的位置并不相同.并用384个交通事件数据对模型的预测精度进行检验.检验结果表明,抛锚事件持续时间预测误差小于10 min的正确率为79%,而交通事故持续时间预测误差小于20 min的正确率为65%.基于贝叶斯推理的决策树算法比仅基于贝叶斯或仅基于决策树算法的分类精度更高,鲁棒性更强.     

基于主成分分析的上市公司财务危机预警模型研究

建立了主成分分析预警模型,该模型可以用来对企业财务困境进行预测.经实证研究得出,该模型对检验样本的预测正确率为70%,说明主成分分析方法对上市公司的财务危机具有较好的预测效果.     

由氨基酸序列预测蛋白质二级结构的进一步研究

本文在工作[1][2]的基础上进一步研究了蛋白质二级结构的经验预测,着重讨论了如何制定预测规则的问题,并将预测工作计算机化.在蛋白质资料库中随机选取了21个蛋白质(3296残基)进行预测,正确率对α螺旋和β折迭分别为84.4%和81.9%.     

基于BP神经网络方法的财务预警模型研究

本文通过BP神经网络方法来建立我国上市公司财务失败的预警模型,该模型对检验样本的预测正确率为85%,实证研究表明,该模型具有较好的预测效果。     

芳香族化合物的快速生物降解性QSBR研究

分别采用线性基团贡献、支持向量机与人工神经网络法对芳香族化合物的快速生物降解性进行定量结构-生物降解关系(QSBR)研究,得到不同基团对芳香族化合物快速生物降解性的贡献值。线性基团贡献法对于训练组和测试组的预测正确率是80.3%和79.2%,总的预测正确率达80.1%;支持向量机的预测正确率分别是84.8%、85.4%和84.9%,而人工神经网络法的预测正确率分别是97.7%、81.2%和95.2%。结果表明,这3种方法的预测效果均较好。     

彩色多普勒监测胎盘循环与围产儿不良结局的关系

目的通过回顾性分析93例具不良围产儿结局的孕妇UmA、UtA超声检测结果,探讨了CDFI对围产儿发病的预测价值及病理生理意义.方法将异常组与正常组的UmA、UtA频谱PI、RI、S/D3项阻力指标进行比较,并作统计学处理.结果异常组UmA和UtA血流各项指标均明显高于正常组(P<0.01和P<0.05),且得出3项指标综合预测围产儿发病的敏感性UmA、UtA分别为86.2%和46.8%,特异性分别为73.1%和87.2%,正确率分别为91.6%和72.2%和NICU、IUGR早产3项UmA比UtA预测价值更大,宫内窘迫及围产期死亡项仅UmA阻力指标有预测价值,两动脉阻力指标均异常,则围产儿预后更差.结论CDFI用于围产期胎盘循环的监测,能尽早发现胎盘功能的异常,对围产儿不良结局有较好的预测价值.     

人类病毒蛋白质磷酸化修饰位点的识别研究

蛋白质磷酸化翻译后修饰在病毒的复制和抑制宿主细胞功能方面发挥重要的作用。然而,利用实验的方法识别磷酸化位点既费时费力又耗财。因此基于蛋白质氨基酸序列发展一种机器学习方法对病毒蛋白磷酸化位点进行预测显得非常有必要。研究结合支持向量机提出识别病毒蛋白磷酸化位点的新方法。采用权重氨基酸成分和属性分组编码对病毒蛋白残基的氨基酸物理化学性质和序列信息进行特征提取,通过10倍交叉验证,丝氨酸、苏氨酸和酪氨酸磷酸化位点的预测准确率分别达到82.0%、85.8%和92.4%。运用该预测模型对丝氨酸残基磷酸化的激酶组进行分类评估,CMGC、AGC和CAMK激酶组的马氏相关系数分别达到69.3%、68.8%和68.2%。结果表明:构建的方法可以有效地预测激酶特异性的磷酸化位点。     

基于遗传算法和神经网络的上市公司财务困境预测

针对上市公司财务困境预测问题,以中国制造业上市公司为研究对象,以财务状况异常而被特别处理作为上市公司陷入财务困境的标志,将股权结构和董、监事会状况指标加入到财务预警的指标体系中,应用遗传算法优化的BP神经网络算法,并对独立检验样本集进行预测,将预测结果同logistic方法、支持向量机方法和BP神经网络方法进行比较。结果表明,GA-BP神经网络方法在提前两年和三年预测中,总正确率分别达到91.25%和82.5%,优于其他方法,具有较大的应用价值。     

决策树算法预测人类病毒的蛋白质磷酸化位点

本文基于决策树分类算法构建人类病毒蛋白质磷酸化修饰位点的预测模型。采用氨基酸物理化学性质对蛋白质序列进行特征提取,并分析丝氨酸、苏氨酸和酪氨酸磷酸化位点邻近序列的氨基酸性质。同时考察了不同分类算法对预测结果的影响。通过10倍交叉验证,利用决策树算法预测丝氨酸、苏氨酸和酪氨酸磷酸化位点的MCC分别达到77.31%、75.91%和71.94%,表明本文提出的方法能有效地预测人类病毒的磷酸化修饰位点。     

基于判别分析方法的上市公司财务危机预警研究

近年来,我国经济飞速发展,但也存在影响经济发展因素,它可能使企业陷入财务危机,因此非常有必要建立财务预警系统。本文通过建立判别分析预警模型对财务困境进行预测,经实证研究得知该模型对检验样本的预测正确率为80%,说明判别分析方法对上市公司的财务危机具有较好的预测效果。     

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.     

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.     

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.     

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.     

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.     

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.     

Achieving Unusual States of Matter Under High Pressure

正The periodicity of the elements and the non-reactivity of the inner-shell electrons are two related principles of chemistry,rooted in the atomic shell structure.Within compounds,Group I elements,for example,invariably assume the+1 oxidation state,and their chemical properties differ completely from those of the p-block elements.These general rules govern our understanding of chemical structures and reactions.Using first principles calcula-     

Exchange-Correlation and Electronic Excitation Energies from Pairing Matrix Fluctuations

We have developed an adiabatic connection to formulate the ground-state exchange-correlation energy in terms of pairing matrix linear fluctuations.This formulation of the exchange-correlation energy opens a new channel for density functional approximations based on the many-body perturbation theory.We illustrate the potential of such approaches with an approximation based on the particle-particle Random Phase Approximation(pp-RPA).This re-     

Density Functional Theory for the Response of Periodic Systems to Electric Fields Based on the Vector Potential Approach

正The electronic and nuclear(structural/vibrational)response of 1D-3D nanoscale systems to electric fields gives rise to a host of optical,mechanical,spectral,etc.properties that are of high theoretical and applied interest.Due to the computational difficulty of treating such large systems it is convenient to model them as infinite and periodic(at least,in first approximation).The fundamental theoretical/computational problem in doing so is that