一种超算系统的强度可用性建模与评估

可用性评估越来越注重用户的感知,强度可用性就是这样一种能反映用户所感知的系统计算能力的可用性评估指标。然而超算系统所面对的用户有很多,他们在不同层次上与系统交互,因此所感知的强度可用性各不相同,但相互之间存在关联。若分别为他们建模求解,既会造成很多重复性工作,也会延长评估的过程。提出一种名为UHAM（User-oriented Hierarchical AvailabilityModeling）的、基于层次化建模的强度可用性评估方法,实现了一次建模与求解能满足多个评估需求的目的。UHAM方法独立于系统的具体结构,因而具有普适性。     

基于PCTBTA任务模型的用户界面开发方法

为了适应普适计算环境中用户、设备、使用环境和开发平台的多样性,基于模型的方法被应用于用户界面开发过程中,试图在抽象层次上描述界面,通过模型转换,使其适用于不同的平台.然而,由于目前基于模型的用户界面开发方法（model-based user interface development,简称MBUID）中所采用任务模型的局限性,致使生成的界面难以满足动态环境下用户的可用性需求.提出一种基于任务模型的用户界面开发框架,旨在建模和生成有效、高效、令用户满意的用户界面.在可用性方面,为了准确描述普适计算环境中用户任务,提出一种基于感知控制理论的任务分析方法（perceptual-control-theory-based task analysis,简称PCTBTA）,将使用上下文信息引入到任务分析过程中,并且在较高的抽象层次上反映交互的内容,给可用性设计提供任务空间;在技术方面,为PCTBTA任务模型向界面模型的转换提供技术支持.最后,通过实例说明所提出方法的可行性,并通过与其他方法在可用性和性能方面的比较,表明该方法的有效性.     

一种软件体系结构设计决策的建模工具

体系结构设计在整个软件生命周期中起到关键作用,而设计知识的蒸发会导致系统演化花费代价高、涉众之间交流出现障碍、体系结构制品的复用受到限制等问题,为此需要在软件体系结构层次对设计决策进行显式化的建模.基于一种以决策为中心的体系结构设计方法,实现了一个软件体系结构设计决策的建模工具.该工具帮助架构师对体系结构设计中的问题、方案、决策、理由等核心概念进行建模,完成从需求到体系结构的设计过程,并实现了自动化的候选体系结构方案的合成和部分设计理由的捕捉.该工具还提供了体系结构设计模型与设计决策之间的相互追踪性,以及帮助实现体系结构设计过程中设计决策知识的复用.     

用户个性化推荐系统的设计与实现

为实现个性化服务,理解用户兴趣就成了提供服务的关键任务,因此,提出了隐性采集用户浏览内容、用户浏览时间和用户操作时间的信息方法,通过对网络爬虫程序抓取的网页进行内容清洗提取出主要内容之后,利用VSM建立文档模型,并采用SVM分类方法建立推荐库.基于从客户端采集的用户兴趣信息建模,以及根据该模型和推荐库的相似度,给用户推荐信息.此外,给出了基于该模型的推荐原型系统的实现,使用查准率来评价该系统.试验结果表明,系统较好地实现了基于用户兴趣来推荐阅读的信息.     

基于有机计算的网格资源管理模型的研究

网格的复杂性日益增加,网格资源管理成为一项复杂的任务.有机计算能采取适当的措施使网格环境实现自我管理,隐蔽网格系统的复杂性.文中给出网格资源管理的层次式模型,该模型具有四层:本地资源层、全局资源层、本地服务层和用户层.并将该模型嵌入有机计算体系结构中,灵活使用有机计算中的观测器和控制器对网格中各种资源进行监测和控制.该基于有机计算的网格资源管理模型中的观测器和控制器除了具备原有的功能外,还结合网格资源动态、异构、分布等特点,添加了新的功能模块,以方便对网格资源进行管理.该模型有效地提高了资源分配效率,优化了网格资源管理的性能.     

基于RBAC和ECA规则构建的工作流系统

针对工作流建模的复杂性和模型的安全存取控制问题,提出一种通过建立任务节点和路由节点及其依赖关系来创建工作流模型的方法。在任务节点中引入RBAC机制对角色属性进行约束以实现对工作流的安全存取控制。在路由节点中引入ECA规则,灵活地控制了工作流的流程。最后给出利用该方法建立的工作流系统体系结构的描述。     

基于席克定律与费茨定律的菜单可用性研究

针对人机交互界面菜单设计可用性预测问题,以席克定律和费茨定律为建模基础,提出一个全新的菜单交互可用性预测模型。该模型通过设计一种评估用户选择目标菜单项的耗时计算方法,预测对象涵盖从新手到专家所有层次的用户行为。实验结果表明,在用户从新手转换到专家行为的各个阶段,使用该模型预测得到的菜单交互可用性数据与实验测试得到的数据吻合较好,两者相关性达0.968,证明该模型能广泛应用于各类菜单设计过程中的可用性预测工作。     

面向系统辨识的火电控制时序数据可视分析

对火电控制历史数据进行分析和建模,能有效地帮助用户实现更优的机组运行控制.由于这类控制数据的复杂性,传统系统辨识过程非常烦琐,甚至难以得到有效结果.为此,将可视分析技术引入系统辨识中,与自动建模算法集成,设计了面向系统辨识的可视分析系统imDCS,在时序数据特征分析、模型建立和筛选评估以及模型迭代优化等各阶段支持控制系统建模的全过程.通过多种可视化映射技术和交互联动视图支持多层次模型筛选过程;通过分组视图与堆叠视图展示高维多元模型结构;通过精度评估组合视图支持用户从不同侧面评估模型性能.与领域专家合作,基于电厂真实控制数据和运行优化需求进行了案例分析和评估,结果表明,该系统在工业控制数据分析和建模中具有更高的有效性和可用性.     

基于知觉控制的用户界面设计研究

随着普适计算环境的迅猛发展,越来越多的普通大众需要自己来完成过去必须由业务人员代理才能完成的任务。这使得传统面向业务的交互设计技术不再满足大众对普适计算的可用性需求。提出一种基于知觉控制的用户界面设计技术,旨在给普通大众提供一种易于学习、理解、操作的用户界面。该用户界面设计技术采用基于知觉控制的任务分析以及“参与式设计”的方法,使得用户能够在意图层次,而非业务层次,进行交互,以满足普适环境下可用性设计的需求。     

面向服务的领域分析方法的研究

领域工程为软件复用提供了有力的支持,服务凭借良好的可用性、灵活性和可扩展性得到了广泛应用。本文详细阐述面向服务的领域分析方法中服务特征的抽取过程和领域服务特征的建模过程,提出一种服务组合的方法来增大服务的粒度和可复用性,并将服务特征模型分为4个层次,以实现服务特征模型向体系结构模型的转换。     

The Relationship Between System Effectiveness and Subjective Usability Scores Using the System Usability Scale

This article examines the relationship between users’ subjective usability assessments, as measured using the System Usability Scale (SUS), and the ISO metric of effectiveness, using task success as the measure. The article reports the results of two studies designed to explore the relationship between SUS scores and user success rates for a variety of interfaces. The first study was a field study, where stereotypical usability assessments on a variety of products and services were performed. The second study was a well-controlled laboratory study where the level of success that users were able to achieve was controlled. For both studies, the relationship between SUS scores and their attendant performance were examined at both the individual level and the average system level. Although the correlations are far from perfect, there are reliable and reasonably strong positive correlations between subjective usability measures and task success rates, for both the laboratory and field studies at both the individual and system level.     

The integration of home-automation and IPTV system and services

In this paper we propose the integration of a home-automation system and its services (HASS) with an IPTV system and its services (IPTVSS) to enable convergence at the network-technology and user-interface levels. The convergence at the network-technology level was achieved by using the Internet protocol (IP), and therefore both integrated systems have to provide IP connectivity. To enable communication between the HASS and the IP-based services, we have implemented the WebService/Konnex gateway. The IPTVSS are IP based; therefore, an easy convergence at the network-technology level is possible. The convergence at the user-interface level was achieved by a hardware and software user-interface implementation.     

User-Centered Standardization of Industrial Process Control User Interfaces

This article shows how usability engineering methods-presented in Burmester, Komischke, and Wust (this issue)-were successfully applied to user-interface design in industrial process control. The goal of the research was to optimize the work of both designers (automation engineers) and end users (operators) of process control systems. Expert interviews and task analyses in different sectors were carried out. For the first time operator core sequences were identified in the field and across sectors. For these common activities, software building blocks were conceptually specified and a prototype was evaluated iteratively in the field using demonstrations, focused interviews, usability tests, and questionnaires.     

Architectural support for cooperative multiuser interfaces

Computer support for cooperative work requires the construction of applications that support interaction by multiple users. The highly dynamic and flexible nature of cooperative work makes the need for rapid user-interface prototyping a central concern. We have designed and developed a software architecture that provides mechanisms to support rapid multiuser-interface construction and distributed user-interface management. Rapid prototyping requires mechanisms that make the information determining interface configuration visible, accessible, and tailorable. We developed the architecture as part of a project investigating support for the cooperative work of air traffic controllers. Extensive use of prolonged ethnographic investigation helped to uncover the nature of cooperation in air traffic control. The aim of the architecture is to support an environment in which a multidisciplinary team can experiment with a wide range of alternate user-interface designs for air traffic controllers. Thus, we use examples from this domain to illustrate the architecture     

TADEUS: seamless development of task-based and user-orientedinterfaces

Task-based and user-oriented user interfaces utilize knowledge about user tasks and user characteristics to the utmost extent. They support users throughout their work flows, and must be constructed by a development process that avoids loss of application context and involves user feedback, from requirements specification to code generation. The concepts behind the task analysis/design/end users systems (TADEUS) approach to enable seamless task-based development are a semantically rich representation scheme, a model-driven development procedure, a diagrammatic notation and unifying specification scheme. Thus, interactive applications can be developed seamlessly. Specifications comprise problem domain knowledge, work processes, user roles and personal profiles, as well as interaction modalities (required for task accomplishment). For user-interface prototyping the TADEUS environment contains a model interpreter that executes structure and behavior specifications. This way, early feedback on task-based portals can be provided by users. In this paper we detail the latest developments in the TADEUS project when implementing a work-process based usability life cycle. We review the underlying methodology and the features of the TADEUS environment, in order to demonstrate the benefits for developers and users resulting of smooth transition support for and between the different stages of development     

Automatic usability and stress analysis in mobile biometrics

This article focuses on the usability evaluation of biometric recognition systems in mobile devices. In particular, a behavioural modality has been used: the dynamic handwritten signature. Testing usability in behavioural modalities involves a big challenge due to the number of degrees of freedom that users have in interacting with sensors, as well as the variety of capture devices to be used. In this context we propose a usability evaluation that allows users to interact freely with the system while minimizing errors at the same time. The participants signed in a smartphone with a stylus through the different phases in the use of a biometric system: training, enrolment and verification. In addition, a profound study on the automation of the evaluation processes has been done, so as to reduce the resources employed. The influence of the users' stress has also been studied, to obtain conclusions on its impact on both the usability systems in scenarios where the user may suffer a certain level of stress, such as in courts, banks or even shopping. In brief, the results shown in this paper prove not only that a dynamic handwritten signature is a trustable solution for a large number of applications in the real world, but also that the evaluation of the usability of biometric systems can be carried out at lower costs and shorter duration.     

Evaluation of EIS from a managerial perspective1

Abstract. While executive information systems (EIS) constitute a rising trend in the use of information technology in organizations, much is still unknown in terms of the attributes an EIS should possess in order to increase the probability of successful implementation. A survey was conducted on 28 Canadian organizations, with 52 users giving their perceptions on the various attributes of EIS. Results indicate that the more important aspects relate to the quality of information and the benefits provided by EIS. Less important are the user-interface and technical capabilities. User satisfaction with the attributes of their present system was also measured. In this regard, managers were more content with the quality of information and the user-interface than with the benefits and the technical capabilities of their EIS. Overall, top-managers were less satisfied with the present system than lower-level managers.     

Experiencing OptiqueVQS: a multi-paradigm and ontology-based visual query system for end users

Data access in an enterprise setting is a determining factor for value creation processes, such as sense-making, decision-making, and intelligence analysis. Particularly, in an enterprise setting, intuitive data access tools that directly engage domain experts with data could substantially increase competitiveness and profitability. In this respect, the use of ontologies as a natural communication medium between end users and computers has emerged as a prominent approach. To this end, this article introduces a novel ontology-based visual query system, named OptiqueVQS, for end users. OptiqueVQS is built on a powerful and scalable data access platform and has a user-centric design supported by a widget-based flexible and extensible architecture allowing multiple coordinated representation and interaction paradigms to be employed. The results of a usability experiment performed with non-expert users suggest that OptiqueVQS provides a decent level of expressivity and high usability and hence is quite promising.     

How do usability professionals construe usability?

Usability professionals have attained a specialist role in systems-development projects. This study analyses usability professionals’ operational understanding of usability by eliciting the constructs they employ in their thinking about system use. We approach usability broadly and without a priori distinguishing it from user experience. On the basis of repertory-grid interviews with 24 Chinese, Danish, and Indian usability professionals we find that they make use of more utilitarian than experiential, i.e. user-experience related, constructs. This indicates that goal-related performance is central to their thinking about usability, whereas they have less elaborate sets of experiential constructs. The usability professionals mostly construe usability at an individual level, rather than at organizational and environmental levels. The few exceptions include effectiveness constructs, which are evenly spread across all three levels, and relational constructs, which are phrased in terms of social context. Considerations about users’ cognitive activities appear more central to the usability professionals than conventional human-factors knowledge about users’ sensorial abilities. The usability professionals’ constructs, particularly their experiential constructs, go considerably beyond ISO 9241 usability, indicating a discrepancy between this definition of usability and the thinking of the professionals concerned with delivering usability. Finally, usability is construed rather similarly across the three nationalities of usability professionals.