Oracle数据库跨平台数据迁移研究

从数据迁移的实际需求出发,比较Oracle数据库三种标准备份方法的优缺点,分析Oracle导出文件的结构,给出Oracle数据库从Windows平台到UNIX平台数据迁移的实现方法。     

Bridging the gap between role mining and role engineering via migration guides

In the context of role-based access control (RBAC), mining approaches, such as role mining or organizational mining, can be applied to derive permissions and roles from a system's configuration or from log files. In this way, mining techniques document the current state of a system and produce current-state RBAC models. However, such current-state RBAC models most often follow from structures that have evolved over time and are not the result of a systematic rights management procedure. In contrast, role engineering is applied to define a tailored RBAC model for a particular organization or information system. Thus, role engineering techniques produce a target-state RBAC model that is customized for the business processes supported via the respective information system. The migration from a current-state RBAC model to a tailored target-state RBAC model is, however, a complex task. In this paper, we present a systematic approach to migrate current-state RBAC models to target-state RBAC models. In particular, we use model comparison techniques to identify differences between two RBAC models. Based on these differences, we derive migration rules that define which elements and element relations must be changed, added, or removed. A migration guide then includes all migration rules that need to be applied to a particular current-state RBAC model to produce the corresponding target-state RBAC model. We conducted two comparative studies to identify which visualization technique is most suitable to make migration guides available to human users. Based on the results of these comparative studies, we implemented tool support for the derivation and visualization of migration guides. Our software tool is based on the Eclipse Modeling Framework (EMF). Moreover, this paper describes the experimental evaluation of our tool.     

‘Migrating to a new virtual world’: Exploring MMORPG switching through human migration theory

Online gaming has become a popular leisure-time activity. In this study, we enlisted and adapted the Push-Pull-Mooring model, which analyzes human migratory behavior based on the Demographic Migration Theory, to study the game switching of gamers. Data was obtained via an empirical survey of 654 online gamers and then was analyzed using the Structural Equation Modeling (SEM) technique. The results indicate that the Push-Pull-Mooring model can be extended to explain the switching intentions of online gamers. The “mooring effect” appears to have a stronger influence on the player’s switching intention than the “pull effect”, while the “push effect” appears to have no influence at all. We discuss the implications of our findings and offer possible avenues of exploration for managers of online game providers in order to help them understand their customers better.     

云环境下面向负载均衡的分布式虚拟机迁移研究

针对云计算环境下主机资源的负载均衡问题,提出一种分布式的虚拟机迁移方案。首先,该方案建立主机状态域模型,将主机分为不同的负载状态;然后借鉴蚁群算法中信息素的思想进行主机搜索,设计信息素的更新规则,得到待迁移的虚拟机列表和目的主机列表;最后将虚拟机列表和目的主机列表进行匹配,得到虚拟机迁移结果,进行迁移。在Cloudsim环境下进行实验仿真,实验结果证明,使用该方案可获得较好的负载均衡等级。     

融合模式搜索与人口迁移的优化算法

针对人口迁移算法存在的收敛速度慢、优化精度低、易陷入局部最优等问题,提出一种融合模式搜索与人口迁移的优化算法。将模式搜索方法作为一种局部优化算子嵌入到人口迁移算法中,对人口迁移算法随机产生的点利用模式搜索方法进行局部优化。通过5个典型函数进行测试,结果表明,该算法收敛速度快、优化精度高,能有效求解全局优化问题。     

MSC池组用户迁移方法及原理介绍

通过对爱立信MSCPool2种用户迁移方法的原理介绍及实际测试验证，详细地介绍了Pool内用户的迁移流程，为今后需要进行用户迁移方法的选择提供了实践依据。     

核素在非饱和带中迁移的非平衡吸附数值模式——NESOR

本文将对流弥散方程与非平衡吸附关系式相结合，开发了核素在非饱和孔隙介质中迁移的二维非平衡吸附数值模式与计算机程序－ＮＥＳＯＲ，给出了ＮＥＳＯＲ中使用的吸附、解吸速率参数的计算方法。     

运行中的某总变配电所迁移重建方案介绍

介绍某机关大院运行中的总变配电所迁移重建的实施方案。通过对该变配电所运行现状的分析,明确改造范围、改造方法和实施步骤。     

Stability of CdTe/CdS thin-film solar cells

The recent literature regarding the stability of CdTe/CdS photovoltaic cells (as distinguished from modules) is reviewed. Particular emphasis is given to the role of Cu as a major factor that can limit the stability of these devices. Cu is often added to improve the ohmic contact to p-CdTe and the overall cell photovoltaic performance. This may be due to the formation of a Cu₂Te/CdTe back contact. Excess Cu also enhances the instability of devices when under stress. The Cu, as Cu⁺, from either Cu₂Te or other sources, diffuses via grain boundaries to the CdTe/CdS active junction. Recent experimental data indicate that Cu, Cl and other diffusing species reach (and accumulate at) the CdS layer, which may not be expected on the basis of bulk diffusion. These observations may be factors in cell behavior and degradation, for which new mechanisms are suggested and areas for future study are highlighted. Other possible Cu-related degradation mechanisms, as well as some non-Cu-related issues for cell stability are discussed.     

浅谈差压变送器的迁移

本文详细论述了差压变送器测液面迁移的原理,并结合经验给出了带迁移的差压变送器故障的具体分析方法.