Distributed and Collaborative Visualization

Visualization is a powerful tool for analyzing data and presenting results in science, engineering and medicine. This paper reviews ways in which it can be used in distributed and/or collaborative environments. Distributed visualization addresses a number of resource allocation problems, including the location of processing close to data for the minimization of data traffic. The advent of the Grid Computing paradigm and the link to Web Services provides fresh challenges and opportunities for distributed visualization—including the close coupling of simulations and visualizations in a steering environment. Recent developments in collaboration have seen the growth of specialized facilities (such as Access Grid) which have supplemented traditional desktop video conferencing using the Internet and multicast communications. Collaboration allows multiple users—possibly at remote sites—to take part in the visualization process at levels which range from the viewing of images to the shared control of the visualization methods. In this review, we present a model framework for distributed and collaborative visualization and assess a selection of visualization systems and frameworks for their use in a distributed or collaborative environment. We also discuss some examples of enabling technology and review recent work from research projects in this field.     

嵌入式网络软件体系结构研究及应用

该文从PC领域的软件体系结构出发,针对嵌入式应用的特殊性,对嵌入式领域的网络软件体系结构进行了系统的概述及总结,并提出了两种新型的体系结构:“HICP”、“XML&B/S”。“HICP”体系结构是基于自行设计的“HICP”协议及“HICP”代理服务器的一种新型体系结构,具有开发简单方便、效率高等优点;“XML&B/S”是从“B/S”框架发展而来,客户端与服务器端通信的数据采用“XML”格式。此外,该文还介绍了这两种新型的软件体系结构在实际系统中应用。     

Software Agent-Oriented Frameworks for Global Query Processing

The paper introduces the concept of software agent-oriented frameworks for global query processing in an interoperable environment. Such an environment is developed for the purpose of making cooperative interactions between several systems. These latter are distributed on networks and may present several incompatibilities. The global query processing is applied to the SIGAL project which aims at developing an interoperable environment for georeferenced digital libraries. This environment provides users with services that will free them from worrying about information distribution and disparities.     

Programming distributed and adaptable autonomous components—the GCM/ProActive framework

Component‐oriented software has become a useful tool to build larger and more complex systems by describing the application in terms of encapsulated, loosely coupled entities called components. At the same time, asynchronous programming patterns allow for the development of efficient distributed applications. While several component models and frameworks have been proposed, most of them tightly integrate the component model with the middleware they run upon. This intertwining is generally implicit and not discussed, leading to entangled, hard to maintain code. This article describes our efforts in the development of the GCM/ProActive framework for providing distributed and adaptable autonomous components. GCM/ProActive integrates a component model designed for execution on large‐scale environments, with a programming model based on active objects allowing a high degree of distribution and concurrency. This new integrated model provides a more powerful development, composition, and execution environment than other distributed component frameworks. We illustrate that GCM/ProActive is particularly adapted to the programming of autonomic component systems, and to the integration into a service‐oriented environment. Copyright © 2014 John Wiley & Sons, Ltd.     

A tool supporting root cause analysis for synchronous retrospectives in distributed software teams

ContextRoot cause analysis (RCA) is a useful practice for software project retrospectives, and is typically carried out in synchronous collocated face-to-face meetings. Conducting RCA with distributed teams is challenging, as face-to-face meetings are infeasible. Lack of adequate real-time tool support exacerbates this problem. Furthermore, there are no empirical studies on using RCA in synchronous retrospectives of geographically distributed teams.ObjectiveThis paper presents a real-time cloud-based software tool (ARCA-tool) we developed to support RCA in distributed teams and its initial empirical evaluation. The feasibility of using RCA with distributed teams is also evaluated.MethodWe compared our tool with 35 existing RCA software tools. We conducted field studies of four distributed agile software teams at two international software product companies. The teams conducted RCA collaboratively in synchronous retrospective meetings by using the tool we developed. We collected the data using observations, interviews and questionnaires.ResultsComparison revealed that none of the existing 35 tools matched all the features of our ARCA-tool. The team members found ARCA-tool to be an essential part of their distributed retrospectives. They considered the software as efficient and very easy to learn and use. Additionally, the team members perceived RCA to be a vital part of the retrospectives. In contrast to the prior retrospective practices of the teams, the introduced RCA method was evaluated as efficient and easy to use.ConclusionRCA is a useful practice in synchronous distributed retrospectives. However, it requires software tool support for enabling real-time view and co-creation of a cause-effect diagram. ARCA-tool supports synchronous RCA, and includes support for logging problems and causes, problem prioritization, cause-effect diagramming, and logging of process improvement proposals. It enables conducting RCA in distributed retrospectives.     

Why do users like video?

Three studies of collaborative activity were conducted as part of research in developing multimedia technology to support collaboration. One study surveyed users' opinions of their use of video conference rooms. Users indicated that the availability of the video conference rooms was too limited, audio quality needed improvement, and a shared drawing space was needed. A second study analyzed videotapes of a work group when meeting face-to-face, video conferencing, and phone conferencing. The analyses found that the noticeable audio delay in video conferencing made it difficult for the participants to manage turn-taking and coordinate eye glances. In the third study, a distributed team was observed under three conditions: using their existing collaboration tools, adding a desktop conferencing prototype (audio, video, and shared drawing tool), and subtracting the video capability from the prototype. Qualitative and quantitative data were collected by videotaping the team, interviewing the team members individually, and recording their usage of the phone, electronic mail, face-to-face meetings, and desktop conferencing. The team's use of the desktop conferencing prototype dropped significantly when the video capability was removed. Analysis of the videotape data showed how the video channel was used to help mediate their interaction and convey visual information. Desktop conferencing apparently reduced e-mail usage and was perceived to reduce the number of shorter, two-person, face-to-face meetings.     

一种基于JNDI的分布式软件架构模型

本文基于JNDI技术,提出了一种新的分布式软件架构模型。它与其它分布式软件架构相比,具有同样良好的扩展性、可维护性以及跨平台性。此外,它更适合于架构小中型分布式软件且具有更高的安全性。     

基于J2EE架构的开源速成框架的设计和应用

在J2EE的多层架构下,出现了Struts、Spring、Hibernate等很多优秀的开源框架,但这些开源框架各有所长,本文提出的开源速成框架,以高内聚、低耦合的原则对这些开源框架进行提炼、简化和整合,Web表示层使用速成MVC框架、业务逻辑层使用速成IOC框架、数据访问层使用速成ORM框架,解决了烦琐的基于J2EE的web应用架构建设,规范及简化web应用系统的开发过程,使得架构更加简练灵活快速,并成功应用在B/S架构的多个项目中。     

J2EE轻量级框架的研究与应用

介绍了当前J2EE平台上的轻量级框架组合Struts、Spring、Hibernate,以及每个框架的基本特征及其优势.该轻量级框架可以基于J2EE平台快速开发出企业级的Web应用,它们可以分别应用于Web应用的各层,实现多层开发的低耦合.最后以用户信息管理为例,具体介绍了框架的应用.     

面向智能计算框架的即时缺陷预测

作为人工智能工程化的实现工具,智能计算框架已在近年来被广泛应用,其可靠性对于人工智能的有效实现至关重要.然而,智能计算框架的可靠性保障具有挑战性,一方面,智能计算框架代码迭代迅速、测试困难;另一方面,与传统软件不同,智能计算框架涉及大量张量计算,其代码规范缺乏软件工程理论指导.为了解决这一问题,现有的工作主要使用模糊测试手段实现缺陷定位,然而,这类方法只能实现特定类型缺陷的精准定位,却难以即时地在开发过程中引导开发者关注软件质量.因此,将国内外常见的智能计算框架(TensorFlow,百度飞桨等)作为研究对象,选取多种变更特征构建数据集,在代码提交级别对智能计算框架进行即时缺陷预测.另外,在此基础上使用LDA主题建模技术挖掘代码和代码提交信息作为新的特征,并使用随机森林进行预测.结果发现AUC-ROC平均值为0.77,且语义信息可以略微提升预测性能.最后,使用可解释机器学习方法 SHAP分析各特征属性对模型预测输出的影响,发现:(1)基本特征对于模型的影响符合传统软件开发规律;(2)代码和提交信息中的语义特征对模型的预测结果有重要影响;(3)不同系统中的不同特征对模型预测输出的贡献度排...     

基于Hibernate的数据访问框架扩展点研究

提出一种基于Hibernate的数据访问框架,对其扩展点进行分类和设计研究,根据每类扩展点的特点,给出其设计策略及实现方法。结合实例对每类扩展点的具体实现进行阐述。实验结果表明,该方法能灵活应对数据层上的需求变化,为其他层框架扩展点的研究提供依据。     

一种面向情境的情境感知应用编程框架

随着信息技术的快速发展,各种各样的环境信息影响着我们生活中的各种决策,因此提供一种智能化的应用程序,能够根据用户当前的情境信息为用户提供所需要的最适合的服务变得越来越重要。许多遗产软件并不支持情境感知功能,目前的一些主要的编程语言和编程框架并没有提供一个很好的方式来支持这种情境感知应用程序的开发。提出了一个新的面向情境的编程框架,支持情境信息的定义、封装、发布,支持对应用行为的驱动和约束,允许应用快速响应非预期情境。通过该框架可以快速开发情境感知应用,也可以以非侵入的方式改造遗产软件,使之具有情境感知能力。     

FreeScaler:一个灵活面向领域的可复用基础设施

框架是软件复用研究中的重要课题之一，但是框架在不同的领域中有不同的特性，需要将框架的特性与共性分离，将共性部分单独加以实现并复用，使得研究人员的注意力集中在各个领域的特性部分．本文提出并研发了一个基于构件和双总线的分层微内核结构的基础设施——FreeScaler．该基础设施属于框架共性的实现，具有高度的开放性和灵活性，为科研试验和应用开发提供了一个快捷易用的平台．文中重点介绍了FreeScaler的设计思路、整个系统的模型和体系结构，阐释其关键特性．并展示了基于FreeScaler的实际应用．     

HSRM层次化结构的动态构建和维护

HSRM是我们针对分布式组播会议控制的应用需求提出的层次化可扩展可靠组播通信模型。本文根据分布式组播会议控制在分布性、可扩展性和鲁棒性等方面的要求，以分布、基于组播、自适应、公平和自治为目标，设计了HSRM层次化结构的分布式、自适应构建和维护算法。     

基于Struts—Spring—Hibernate框架的软件复用技术

软件复用是一种由预先构建好的、为复用目的而设计的软件结构来建立或者组装软件系统的过程。采用“高内聚,低耦合”的成熟框架来进行软件开发,是这一过程的一个很好实践。本文在深入研究软件设计模式的基础上,对目前流行的基于Struts—Spring—Hibernate框架进行可复用软件开发技术进行分析和研究。     

视频会议中视频分割合成的研究

视频会议系统正在吸引越来越多在地域上分散的人们的注意。随着多媒体信息处理和通信技术的飞速发展，虚拟视频会议系统越来越成为可能。和传统的基于二维图像表述的视频会议系统比较，三维虚拟会议系统能为人们提供更好的以人为中心的交流。在这两种情况下，高效精确的视频分割和视图合成都是关键问题。就以下3方面的主要技术进行了研究：背景分离、视差估计以及视图合成。     

Distributed SIP conference management with autonomously authenticated sources and its application to an H.264 videoconferencing software for mobiles

The design of conferencing systems for achieving efficient and flexible communication in a fully distributed, infrastructure-independent fashion is a promising direction, both in terms of research and practical development. In the particular case of video communication, the seamless adaptation to heterogeneous mobile devices poses an additional strong challenge to those seeking for interoperable and easy-to-deploy solutions. In this paper, we make several contributions towards a generic peer-to-peer (P2P) videoconferencing solution that extends into the mobile realm. We describe the essential building blocks for conference management and media distribution that are necessary for a distributed conferencing approach. Establishing a distributed SIP conference focus, participants share the conference according to their individually given capabilities and resources in terms of bandwidth and processing power rather than in a centralized and fixed way. Overall concepts and SIP-primitives for such an autonomous organization are presented. Security issues that derive from this decentralized identity management are resolved by so-called Overlay AuthoCast, a novel use of cryptographically generated identifiers. Furthermore, this work is dedicated to the development of a software-based H.264 video codec implementation and the specific aspects resulting from tuning such a highly resource-intensive software codec to the given target platform of a standard consumer smartphone.     

基于分布式代理的自适应视频会议系统的设计

如何克服服务器负载过重造成的瓶颈效应,及如何适应网络的动态变化,是视频会议系统一直面临的问题.提出了一种基于分布式代理的自适应视频会议系统.该系统充分利用当前的网络条件,采用分布式代理,使用应用层组播和IP层组播相结合的混合组播方式,解决了服务器瓶颈问题;采用基于MPEG-4FGS速率修整技术,使系统具有极好的网络自适应性.     

基于工作流与Web Portal的分布式软件框架研究

基于表示、业务逻辑和数据的三层软件体系结构已成为大规模分布式软件系统的基本模式。针对其结构灵活、可维护、易扩展的进一步需求,探讨了采用Web Portal实现表示层,采用工作流实现逻辑层的技术思路;在此基础上,为三层软件体系结构设计了一种通用、灵活的软件框架;最后,给出了作者实现的框架原型和用例。     

A framework for efficient performance prediction of distributed applications in heterogeneous systems

Predicting distributed application performance is a constant challenge to researchers, with an increased difficulty when heterogeneous systems are involved. Research conducted so far is limited by application type, programming language, or targeted system. The employed models become too complex and prediction cost increases significantly. We propose dPerf, a new performance prediction tool. In dPerf, we extended existing methods from the frameworks Rose and SimGrid. New methods have also been proposed and implemented such that dPerf would perform (i) static code analysis and (ii) trace-based simulation. Based on these two phases, dPerf predicts the performance of C, C++ and Fortran applications communicating using MPI or P2PSAP. Neither one of the used frameworks was developed explicitly for performance prediction, making dPerf a novel tool. dPerf accuracy is validated by a sequential Laplace code and a parallel NAS benchmark. For a low prediction cost and a high gain, dPerf yields accurate results.