Impact analysis and change propagation in service-oriented enterprises: A systematic review

ContextThe adoption of Service-oriented Architecture (SOA) and Business Process Management (BPM) is fairly recent. The major concern is now shifting towards the maintenance and evolution of service-based business information systems. Moreover, these systems are highly dynamic and frequent changes are anticipated across multiple levels of abstraction. Impact analysis and change propagation are identified as potential research areas in this regard.ObjectiveThe aim of this study is to systematically review extant research on impact analysis and propagation in the BPM and SOA domains. Identifying, categorizing and synthesizing relevant solutions are the main study objectives.MethodThrough careful review and screening, we identified 60 studies relevant to 4 research questions. Two classification schemes served to comprehend and analyze the anatomy of existing solutions. BPM is considered at the business level for business operations and processes, while SOA is considered at the service level as deployment architecture. We focused on both horizontal and vertical impacts of changes across multiple abstraction layers.ResultsImpact analysis solutions were mainly divided into dependency analysis, traceability analysis and history mining. Dependency analysis is the most frequently adopted technique followed by traceability analysis. Further categorization of dependency analysis indicates that graph-based techniques are extensively used, followed by formal dependency modeling. While considering hierarchical coverage, inter-process and inter-service change analyses have received considerable attention from the research community, whereas bottom-up analysis has been the most neglected research area. The majority of change propagation solutions are top-down and semi-automated.ConclusionsThis study concludes with new insight suggestions for future research. Although, the evolution of service-based systems is becoming of grave concern, existing solutions in this field are less mature. Studies on hierarchical change impact are scarce. Complex relationships of services with business processes and semantic dependencies are poorly understood and require more attention from the research community.     

基于改进的MSR算法在软件视频会议系统上的应用

视频会议是一种应用广泛的会议方式,由于光照、视频采集设备品质、网络带宽等外界复杂因素的影响,常常导致视频会议视频图像质量下降。在多尺度Retinex滤波(MSR)算法的基础上,使用双边滤波获取原始图像的高低频信息,然后采用颜色约束方法和增益补偿方法增强经过双边滤波处理后的高频反射图像。通过主观体验和客观评价,改进算法增强了视频图像,同时保留了边缘细节,应用于软件视频会议系统,提高了视频图像的清晰度,改善了视觉效果。     

基于多尺度Retinex的自适应图像增强方法

介绍了一种基于MSR的自适应图像增强的方法,能够较好地自动处理由于云雾、雨天等天气原因和光照不足导致的景物不清、视觉质量差和对比度低的图像,提升多种类型的图像视觉质量.通过对实验的结果以及算法的普适性进行比较和分析,证明了该方法是有效的.     

基于多尺度Retinex的雾天降质图象增强算法

雾天图象受到严重退化,大大降低了图象的使用价值。利用Retinex理论的颜色恒常性,通过提取照度分量来去除雾天对图象的退化作用。指出MSR算法处理雾天图象的不足,提出将MSR算法处理结果与原图象结合的改进方法:引入原图象对数分量和颜色信息,以保留原图象亮度的全局对比度和恢复平坦区域的颜色;提出进一步增强雾天图象细节信息的方法:将MSR处理结果与边缘增强的原始图象相结合,然后对输出图象各颜色分量先进行正态截取,再统一拉伸到显示设备的动态范围。实验结果表明,该方法能取得较好的图象去雾效果。     

A mechanistic approach to evaluate the potential of the debonding distress in asphalt pavements

The debonding distress in asphalt pavement structures is a critical problem that affects the performance of asphalt concrete pavements. It occurs at the layer interface due to the poor bond quality between adjacent asphalt concrete layers and/or when stresses at the layer interface exceed the strengths of the material at the interface. The debonding of the adjacent layers, especially the top surface layer of an asphalt pavement, is a contributing factor to the premature cracking of pavements. Hence, the debonding distress can lead to a reduction in the life of the pavement. This paper presents an analytical and experimental framework to evaluate the potential for debonding at the layer interface of asphalt concrete pavements. Computational analysis was performed to determine the critical stress and strain states in layered asphalt pavements under moving vehicle loads using the Layered ViscoElastic pavement analysis for Critical Distresses (LVECD) computer program developed at North Carolina State University. This computational analysis enables a greater understanding of the critical stress that is involved in debonding and the ways that such stress is affected by pavement design parameters and environmental conditions. In addition, a prediction model was developed that can determine the shear bond strength at the interface of asphalt concrete layers with different tack coat materials at various temperatures, loading rates and normal confining stresses. The systematic and mechanistic framework developed in this study employs the maximum shear ratio concept as a shear failure criterion and provides a tool to evaluate the effects of various loading, environmental and pavement factors on the debonding potential of asphalt pavements. The overall advantages of the mechanistic framework and approach using the LVECD analysis tool will help lead to better understanding of the debonding mechanism, proper selection of the tack coats, and economic benefit in highway pavement maintenance and rehabilitation costs.     

基于MSR和边缘提取的彩色图像融合新方法

提出了基于多尺度Retinex（MSR）和边缘提取实施彩色图像融合的一种新方法。多尺度Retinex算法具有突出图像中阴暗区域信息的功能,采用边缘检测的方法提取图像中阴暗区域,将原图像阴暗区域的像素替换成多尺度Retinex增强图像的像素实现彩色图像融合,得到的新图像信息更丰富。在提取闭合区域时,提出了区分真断点和准断点的技术,改进了闭合边缘提取的方法。进而对融合的新图像进行了深入研究,获得埃及Giza金字塔中最大的Khufu金字塔阴影的几何信息。     

Insights into the reaction mechanisms of methanol decomposition,methanol oxidation and steam reforming of methanol on Cu(111): A density functional theory study

Cu-based catalysts have been widely used for hydrogen production from methanol decomposition, methanol oxidation and steam reforming of methanol (MSR). In this study, we have systematically identified possible reaction paths for the thermodynamics and dynamics involved in the three reactions on a Cu(111) surface at the molecular level. We find that the reaction paths of the three reactions are the same at the beginning, where methanol scission is favourable involving O–H bond scission followed by sequential dehydrogenation to formaldehyde. Formaldehyde is an important intermediate in the three reactions, where direct dehydrogenation of formaldehyde to CO is favourable for methanol decomposition; for methanol oxidation, formaldehyde tends to react with oxygen to form dioxymethylene through C–H bond breaking and finally the end products are mainly CO₂ and hydrogen; for MSR, formaldehyde tends to react with hydroxyl to form hydroxymethoxy through formic acid and formate formation, followed by dissociation to CO₂. CH₂O formation from methoxy dehydrogenation is considered to be the rate-limiting step for the three reactions. In general, the thermodynamic and kinetic preference of the three reactions shows the order methanol oxidation > MSR > methanol decomposition. Methanol oxidation and MSR are faster than methanol decomposition by about 500 and 85 times at typical catalytic conditions (e.g., 523 K), respectively. The result may be useful for computational design and optimization of Cu-based catalysts.     

Sequence of the most informative joints (SMIJ): A new representation for human skeletal action recognition

Much of the existing work on action recognition combines simple features with complex classifiers or models to represent an action. Parameters of such models usually do not have any physical meaning nor do they provide any qualitative insight relating the action to the actual motion of the body or its parts. In this paper, we propose a new representation of human actions called sequence of the most informative joints (SMIJ), which is extremely easy to interpret. At each time instant, we automatically select a few skeletal joints that are deemed to be the most informative for performing the current action based on highly interpretable measures such as the mean or variance of joint angle trajectories. We then represent the action as a sequence of these most informative joints. Experiments on multiple databases show that the SMIJ representation is discriminative for human action recognition and performs better than several state-of-the-art algorithms.     

城域网中的多业务环技术

城域网数据业务不断增加,如何提高各类业务的服务质量成为人们面临的问题,ITU-T制订的多业务环技术提供了一种新的解决方法。本文主要讨论多业务环的拓扑结构、协议栈和帧结构等,根据MSR的节点流程图重点研究基于支路的各个功能模块及其各种业务的服务质量保证。最后,还讨论了MSR协议中提供的业务种类及其组网。     

基于MSR局部多径的QoS路由算法

无线多媒体传感网络（WMSN）QoS路由研究的普遍思路是通过增加网络控制负载以保障服务质量（QoS）。针对该思路中网络效率低的缺陷,提出一种应用于Mesh结构WMSN中的,基于局部多径策略的QoS路由算法（PQMSR）。该算法在保障QoS的前提下,参考多径源路由（Multipath Source Routing,MSR）算法,通过局部多径策略和携带QoS信息的IP包头来降低网络控制负载。NS-3网络模拟实验结果表明,该算法能够在保证较高传输成功率的同时,降低网络负载和网络延时。