面向多租户的多层次可伸缩SaaS软件架构研究

针对SaaS模式下面向多租户的SaaS软件如何随着用户数量及请求规模的变化而进行自适应伸缩的问题,在分析SaaS软件的可伸缩需求的基础上,从一个较为宏观的角度提出了一个面向多租户的多层次可伸缩SaaS软件架构.该软件架构将SaaS软件的伸缩层次划分为业务层和数据层两个部分,从应用、流程和构件等三个粒度研究多粒度业务层的动态可伸缩实现方法;在数据层,以内存数据库子层、全局数据库子层以及数据引擎构建一个面向多租户的数据库开发框架,实现租户数据的隔离、存储以及一致性.基于该软件架构,开发了一个面向物流行业的多租户SaaS原型系统,验证了其有效性和可用性.     

基于滤波优化的多租户应用QPN性能建模方法

为分析和评估多租户应用的资源消耗并预测其未来对资源的需求,研究了从细粒度上改进多租户应用性能建模的方法,在使用排队Petri网刻画应用系统能力的基础上,综合考虑工作负载、基础通信流和服务时间等因素,利用Kalman滤波快速适应参数变化的特征,建立优化的多租户应用性能模型。仿真实验表明,建模评估结果与实际性能度量值相比具有可接受的误差值,能较好地反映实际多租户应用的运行状态和预测评估各租户应用的资源需求。     

软件即服务模式下租户多副本数据存储完整性问题研究

针对云中软件即服务(Software as a Service,SaaS)多租户共享存储模式下恶意服务提供商伪造、删除或篡改租户定制存储的数据副本数据问题,结合多租户数据共享存储特点以及租户间隐私与隔离需求,提出了面向租户的多副本完整性保护机制(Tenant-oriented duplication integrity checking scheme,TDIC).TDIC通过对租户副本元组进行周期性随机抽样的方式,来降低验证对象的生成代价.为适应租户数据的动态更新,建立面向租户多副本辅助验证结构(Tenant duplication authentication structure,TDAS),TDAS可以将每个数据节点上不同租户的副本验证信息隔离,保证租户副本验证过程的隔离性.结合租户元组的同态标签与TDAS,TDIC可以在不泄露租户数据内容的前提下,委托可信第三方对租户副本进行抽样检查.分析表明,如果租户逻辑视图中包含一万个数据元组时,在元组破坏率为1%的情况下发现数据被破坏的随机抽样数目最大约为元组总数的5%,相对全部验证的方法有效降低了系统资源消耗.     

基于LQN模型的租户兴趣浏览路径挖掘

面向云计算环境中多租户应用的租户个性化服务需求,从多租户应用日志记录挖掘出租户兴趣浏览路径受到关注。针对传统的以浏览频度为主体的网络拓扑图研究问题,为了更好地找出租户在云平台网站上的兴趣网页,挖掘租户的兴趣浏览路径,综合租户对网页的浏览时长、接收字节数和浏览频度等多个要素定义租户兴趣度,构造租户执行图,纠正路径交叉状况以消除租户执行图中存在的多余路径,对循环路径中的对等节点进行整合以 消除循环嵌套,给出了 一种基于分层排队网（layered queue network, LQN)模型的租户兴趣浏览路径挖掘方法,在此基础上,借助广度优先遍历（breadth first search, BFS)算法进行挖掘。实验证明,改造后的LQN模型在租户兴趣浏览路径挖掘方面的效率有所提高。     

多租户云计算环境下Overlay虚拟化网络研究

从多租户网络技术需求出发,针对现有网络架构面临的困境,通过对3种Overlay技术关键特性的深入分析,以及与现有的相关网络技术进行对比,提出了基于VXLAN技术的Overlay虚拟化网络架构,给出分布式多租户跨越互联网的Overlay技术组网方案,从而解决了多租户网络互通、跨越广域网互联的问题.     

共享数据模式下多租户数据库复制技术研究

复制是一项利用资源副本来提高系统可用性,保证容错性并能提高性能的技术。云计算主要通过服务方式提供动态可伸缩的虚拟化资源,其中通过整合多个租户资源来实现资源共享和规模经济的多租户技术是一项重要技术,而共享数据模式的多租户技术具有最高的共享程度。鉴于云对于高可用性和弹性动态伸缩的需求,本文探讨了传统技术中的复制模型,同时介绍了复制副本之间的一致性维护策略,在此基础上探讨其在共享数据模式多租户技术中的适用性。     

虚拟网络环境下安全服务接入方法

针对传统安全检测工具难以接入云计算虚拟网络环境为不同租户提供安全检测服务的问题,研究了安全检测服务动态接入虚拟网络的方法.通过安全检测服务多进程化、网络功能虚拟化(NFV)技术构建了安全检测服务资源池,从而使安全检测服务器可以并行提供多个服务进程,之后利用软件定义网络(SDN)技术实现了安全检测服务动态接入虚拟网络的方法,使得安全检测服务可以按需、动态地接入租户网络以提供安全服务.实验结果表明:该方法在不破坏租户原有虚拟网络环境隔离性前提下,可以有效地将传统安全检测工具云化、并行地为多租户提供按需动态的安全服务.     

SaaS云服务环境下的管理信息系统方案研究

为了降低北京大学各院系等基层单位的信息化门槛,深化学校信息化建设,根据学校院系管理的需求特点,提出了一种SaaS云服务环境下的管理信息系统方案.探讨了方案的多层次可扩展的应用架构,并且重点研究了其中的3个关键技术:多层次数据存储模型,基于IAAA的多租户访问控制策略MT-IAAA,以及面向多租户的可配置方法和运行机制.     

面向多租户的业务模型版本管理

针对可重用业务模型库的SaaS应用对业务模型版本管理的问题,提出了一个面向多租户的模型版本维护方案.首先提出了面向多租户的业务模型管理架构;接着在模型版本维护方面,给出了一个模型版本维护算法;然后基于该算法,提出了模型文件存储的方式、模型版本控制逻辑以及模型数据存储的方案;最后以一个交通物流行业的信息平台为例验证了该版本维护机制的可行性和正确性.实验证明该方案可以满足多租户模型版本管理的要求.     

云计算数据中心的租户独享VPN的设计与研究

基于云计算数据中心领域在多VPN实例、多租户的情况下,VPN租户如何独享VPN系统、以及VPN租户如何动态分配各自用户VPN权限的方法研究。虚拟专用网络的原则和依据是首先必须符合国家等级保护的法律法规;其次必须满足云服务平台的环境需求;最后根据需求分析,必须满足云服务平台下各个租户、用户、互联网用户、平台间以及虚拟主机间的实际业务需求。接入平台的客户端都通过VPN方式进行访问,确保数据安全,该方案采用硬件VPN系统及虚拟化VPN组件和软件VPN客户端相结合的方式建设平台VPN系统,通过VPN系统的建设可实现网络资源的逻辑划分及安全隔离,使核心网与边缘网络形成一个整体。     

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。     

Quantitative trait loci （QTLs） for quality traits related to protein and starch in wheat

Quality traits in wheat （Triticum aestirum L.） were studied by quantitative trait locus （QTL） analysis in a recombinant inbred line （RIL） population, a set of 131 lines derived from Chuan 35050 × Shannong 483 cross （ChSh）. Grains from RILs were assayed for 21 quality traits related to protein and starch. A total of 35 putative QTLs for 19 traits with a single QTL explaining 7.99-40.52% of phenotypic variations were detected on 10 chromosomes, 1D, 2A, 2D, 3B, 3D, 5A, 6A, 6B, 6D, and 7B. The additive effects of 30 QTLs were positive, contributed by Chuan 35050, the remaining 5 QTLs were negative with the additive effect contributed by Shannong 483. For protein traits, 15 QTLs were obtained and most of them were located on chromosomes 1 D, 3B and 6D, while 20 QTLs for starch traits were detected and most of them were located on chromosomes 3D, 6B and 7B. Only 7 QTLs for protein and starch traits were co-located in three regions on chromosomes 1D, 2A and 2D. These protein and starch trait QTLs showed a distinct distribution pattern in certain regions and chromosomes. Twenty-two QTLs were clustered in 6 regions of 5 chromosomes. Two QTL clusters for protein traits were located on chromosomes 1D and 3B, respectively, three clusters for starch traits on chromosomes 3D, 6B and 7B, and one cluster including protein and starch traits on chromosome 1D.