基于遗传算法优化的神经网络电子邮件信息分类器的研究

结合反垃圾邮件技术的研究,分析了电子邮件数字信息预处理中的特征选择法和将机器学习技术应用于数字信息分类器的方法.针对邮件信息特征向量庞大的问题,提出了GA-CHI特征选择法作为信息预处理,将复杂的邮件数字信息转变成易于机器学习处理的形式.基于BP神经网络电子邮件数字信息分类器,采用遗传算法来优化神经网络邮件数字信息分类器,以进一步提高对中文电子邮件的分类效果.通过对系统的实验分析表明:该文采用的方法能有效地实现对电子邮件数字信息的分类.     

授权重印版西文图书USMARC著录举要

授权重印版西文图书作为一种新型图书，其著录模式需要统一的标准和规范以实现文献资源的共建共享。授权影印版西文图书的分编归属决定了以何种机读目录格式著录的问题；按统一标准与规则以USMARC格式进行著录和编目技术处理，以实现对书目图书的管理和书目数据的资源共建共享。     

数字信息资源选择性保存的策略研究

数字信息资源长期保存不能完全套用印本环境下的保存模式,应根据数字信息的特点和保存原则,确立数字信息资源内容、媒体、技术、格式、模式和标准的选择性保存策略。     

国内外数字信息资源整合管理系统的对比研究与思考

介绍了开发数字信息资源整合管理系统的背景和原理 ,分别从开发背景、结构框架、系统特色、运行环境和遵循标准等各方面深入分析和比较了国内外主要的数字信息资源整合管理系统 .最后分析了建立数字信息整合管理系统的 3种方式 (自主开发、引进国外、购买国内 )的优势和劣势 ,提出建立系统之前应预先做好几方面技术准备     

华北科技学院安全科技数字图书馆建设探讨

数字图书馆是采用计算机技术、网络技术及通信技术所支持的数字信息资源管理及检索系统.为了促进安全工程学科建设,提高安全专业人才培养质量及教学科研水平,建立安全科技数字图书馆这一文献资源管理平台已变得非常重要.本文分析了数字图书馆的内涵特点、建设安全科技数字图书馆的重要性、提出了安全科技数字图书馆在资源建设、网站建设、网络数据存储等方面的一些构想.     

科技期刊文后参考文献著录的规范化问题

科技期刊文后参考文献的著录尚存在著录项目遗漏、著录内容过多及著录错误等问题 .认真学习、执行国家有关标准、规范 ,全面提高文后参考文献著录的标准化、科学化和规范化水平 ,对提高科技期刊整体质量 ,促进学术交流具有积极意义     

标准著录的灵魂——规范与客观原则

如何正确理解和熟练掌握标准著录(它有别于传统著录,即按《中华人民共和国国家标准.普通图书著录规则GB3792.2—85》进行著录,以下简称“标准”)?这是编目员所关心的共同问题.以我拙见,最重要的有两点——规范与客观,理解和应用“标准”要靠它们,对“标准”未规定情况的变通也要靠它们,甚至对“标准”的修订还是要靠它们.规范是约定俗成或明文规定的标准.“标准”是为了健全我国统一的图书报道、检索体系,开展国际目录情报交流,更好地开发和利用文献资源,结合图书的特点和我国文献工作部门的实际情况,于1985年制订并作为国家标准实施的.统一的格式,便于识     

音乐类外文音像资料著录问题的探讨

阐述了音乐类外文音像资料著录标准及特点,在结合MARC21编目格式和利用USMARC著录工作实践的基础上,分析了音乐类外文音像资料的题名著录和责任者著录.     

数字信息长期保存与维护问题研究

对数字信息长期保存的特性进行了深入的分析,并对数字信息长期保存与维护的技术策略、选择策略、管理策略和标准规范进行了探讨.     

学术论文参考文献著录内容错误分析及对策

结合编辑工作实践,从责任者项、题名项和出处项三个方面列举了学术论文中常见的参考文献著录内容错误,分析了这些错误常见的原因,并提出了要从改革管理部门的评价标准、加强作者和编者对参考文献著录的重视等方面减少参考文献著录内容错误。     

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