基于模糊控制的垂直切换决定算法

蜂窝网络(cellular network)与无线局域网(WLAN)的融合是下一代移动通信的发展趋势,在通信过程中,节点将在两种网络间进行垂直切换.文中提出了一种垂直切换决定算法,该算法采用学习机制建立模糊集合的隶属度函数,并从用户对WLAN选择度、WLAN的信号强度以及带宽3个方面进行考虑,通过模糊推理,最终作出切换决定.分析及仿真表明本算法能够在综合多种影响切换的因素基础上作出准确的切换决定,与传统算法相比较,本算法的切换次数降低到传统算法的50%以下.     

异构网络中基于马尔可夫过程的区分业务无线资源管理研究

文中提出了一种基于UTMS蜂窝网络和WLAN异构网络的协同无线资源管理算法.该算法的关键参数包括业务类型、用户终端移动性和位置信息等,协同地利用异构网络中的资源,并同时能保证业务的QoS和业务成本的最小化.通过马尔可夫模型分析了算法的有效性.仿真结果表明,在不同的移动性和网络负荷条件下,文中算法能够明显降低不必要的垂直切换到达率,提供稳定的通信,并有效地提高了系统吞吐量.     

一种基于预注册和预授权无缝切换的TD-SCDMA与WLAN融合的体系结构

伴随TD-SCDMA的独立组网,把TD-SCDMA的优势与高速低成本的WLAN技术相结合的组网方式已经成为当前研究的热点.简要分析了TD-SCDMA和WLAN网络,给出了一种TD-SCDMA和WLAN网络融合的体系结构,对事例体系结构下的切换过程进行了详细描述,并采用预注册和预授权的无缝切换方式来优化切换性能.TD-SCDMA和WLAN网络的融合在功能上实现了对这2种网络的扩展,并使得2种网络的优势更加突出.     

一种TD-SCDMA与WLAN融合体系结构的设计

TD-SCDMA和WLAN(无线局域网)网络的融合在扩展TD-SCDMA网络业务的同时,也从功能上扩展了WLAN网络的接入环境.提出了在热点地区TD-SCDMA与802.11 WLAN的融合体系结构,对这种融合系统结构下的终端模型、资源预留以及切换方式进行了探讨.此融合体系结构方案在对未来移动通信中应用将非常有其竞争力.     

一种基于WLAN的异构网中上行资源分配策略

基于WLAN的异构网中,WLAN可提供较高的速率支持,是对蜂窝网络的有益补充.WLAN的资源管理方式与蜂窝网络的集中式管理不同,存在碰撞和多种速率用户共存时的性能异常,WLAN的碰撞和性能异常情况会形成以最大化网络效用为目标的资源分配问题.由于问题的非凸性,无法直接用凸优化方法求解,为此利用二项分布和泊松分布的近似以及WLAN中用户数和碰撞概率的极限关系,将原问题转换成凸问题,并提出一种满足用户速率需求的分布式资源分配算法,实现WLAN和蜂窝网络间的最优资源分配.仿真结果表明,该算法对系统性能具有较大的改善,提高了AP的利用率.     

智能电网应用中ZigBee网络多信道干扰避免策略(英文)

智能电网是一种新颖的数字化的电气网络,它将电能的生产、配送和控制有机地整合在一起.ZigBee网络由于具有低成本、低功耗、低数据率以及低复杂度等特点,适合应用于智能电网;但是其与无线局域网(WLAN)在同一区域共存将造成ZigBee网络性能的显著下降.针对这一问题,提出了一种多信道的干扰避免策略.通过应用多信道通信的方法,传统的信道切换算法中的"信道切换请求(CSR)的传输受干扰影响"问题得到解决,从而提高了CSR传输的可靠性.实验结果表明,与传统的信道切换算法相比,本文提出的干扰避免策略提高了信道切换的成功率,增强了ZigBee网络在 WLAN 干扰下的可靠性.     

基于接收信号强度预测的自适应垂直切换算法

城市部署的超密集异构无线网络中车辆终端的运动状态和业务类型差异巨大,针对不同运动状态和业务类型的终端并发接入导致的频繁切换和拥塞问题,提出一种基于接收信号强度预测的自适应垂直切换算法。在切换触发阶段使用长短时记忆神经网络预测接收信号强度,在信道链路质量恶化之前提前触发切换,在网络选择阶段综合考虑网络参数以及终端在不同运动状态和业务类型下的接入偏好,并选出综合效益值最高的网络作为切换目标网络。仿真结果表明,该算法能更好地适应终端运动状态和业务类型的变化,能降低不必要的切换次数和网络拥塞度。     

一种基于预注册和预授权无缝切换的TD-SCDMA

伴随TD-SCDMA的独立组网,把TD-SCDMA的优势与高速低成本的WLAN技术相结合的组网方式已经成为当前研究的热点。简要分析了TD-SCDMA和WLAN网络,给出了一种TD-SCDMA和WLAN网络融合的体系结构,对事例体系结构下的切换过程进行了详细描述,并采用预注册和预授权的无缝切换方式来优化切换性能。TD-SCDMA和WLAN网络的融合在功能上实现了对这2种网络的扩展,并使得2种网络的优势更加突出。     

一种新的基于缓存的WLAN快速切换方案

通过分析移动终端切换的过程和现有的改进方案,提出了一种新的快速切换方案——基于分片Cache更新的WLAN快速切换方案.该改进方案由基于动态域值的Cache更新策略、AP负载均衡策略和分片信道扫描的Cache更新策略组成.实验表明:该方案有效的避免了移动终端在静止和AP信号较好的条件下的Cache更新;在保证Cache及时更新的同时降低每次更新Cache的开销且又能有效减小切换时延,同时在AP选择时很好的考虑了AP的负载均衡.因此该方案能够显著得提高移动终端在AP间切换得性能.     

异构网络垂直切换性能参数分析及算法研究

以蜂窝网与无线局域网(WLAN)融合为例,研究异构网络之间的垂直切换算法.对影响切换算法性能的各网络端及用户端参数进行了分析研究,包括参数的定义、在不同接入网中的取值范围、参数之间的关系及参数的归一化等.针对参数对切换算法及系统性能的影响,进行了参数分类,将参数分为切换先决条件、切换判决条件及切换辅助条件,并根据参数分类提出了新的垂直切换算法.该算法采用可变权值,即算法中各性能参数的权值依据用户业务特性,移动模型及用户对各网络的喜好等因素进行动态调整.与目前固定权值的垂直切换算法相比.提出的算法考虑了不同用户特性及QoS需求,可提高用户满意度及网络整体性能.     

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