Perspective-based Usability Inspection: An Empirical Validation of Efficacy

Inspection is a fundamental means of achieving software usability. Past research showed that the current usability inspection techniques were rather ineffective. We developed perspective-based usability inspection, which divides the large variety of usability issues along different perspectives and focuses each inspection session on one perspective. We conducted a controlled experiment to study its effectiveness, using a post-test only control group experimental design, with 24 professionals as subjects. The control group used heuristic evaluation, which is the most popular technique for usability inspection. The experimental design and the results are presented, which show that inspectors applying perspective-based inspection not only found more usability problems related to their assigned perspectives, but also found more overall problems. Perspective-based inspection was shown to be more effective for the aggregated results of multiple inspectors, finding about 30% more usability problems for 3 inspectors. A management implication of this study is that assigning inspectors more specific responsibilities leads to higher performance. Internal and external threats to validity are discussed to help better interpret the results and to guide future empirical studies.     

A Usability Checklist for the Usability Evaluation of Mobile Phone User Interface

In the last decade, the research of the usability of mobile phones has been a newly evolving area with few established methodologies and realistic practices that ensure capturing usability in evaluation. Thus, there exists growing demand to explore appropriate evaluation methodologies that evaluate the usability of mobile phones quickly as well as comprehensively. This study aims to develop a task-based usability checklist based on heuristic evaluations in views of mobile phone user interface (UI) practitioners. A hierarchical structure of UI design elements and usability principles related to mobile phones were developed and then utilized to develop the checklist. To demonstrate the practical effectiveness of the proposed checklist, comparative experiments were conducted on the usability checklist and usability testing. The majority of usability problems found by usability testing and additional problems were discovered by the proposed checklist. It is expected that the usability checklist proposed in this study could be used quickly and efficiently by usability practitioners to evaluate the mobile phone UI in the middle of the mobile phone development process.     

一种基于可用度的Web服务可用性测量模型

Web服务通常运行于一个动态和开放的网络环境中,其底层平台与面向的用户千差万别,这使得Web服务的可用性经常不能得以保证。如何对Web服务可用性进行合理评估并提高服务质量是一个具有挑战性的研究课题。从服务请求者的角度出发,设计一种基于可用度的Web服务可用性测试模型,通过采集原始指标数据对服务质量进行可用度量化评估,为服务请求者选择更佳的Web服务提供参考依据。     

DEEP: Design-Oriented Evaluation of Perceived Usability

Existing perceived usability questionnaires detect the appearance of usability issues rather than the underlying design generating those issues. This limits the capability of existing instruments to directly inform design recommendations. To address this problem, a usability questionnaire structured around the analytical composition of the design was created and validated. A four-stage process was followed. First, 3 usability experts refined 54 questions from highly cited usability questionnaires and structured them around 6 design dimensions. Second, 12 raters scored the questions by their relevance to assess usability. Third, questions and dimensions were then improved through exploratory and confirmatory factor analysis (N?=?196) and, fourth, further enhanced through confirmatory factor analysis (N?=?362). The result is DEEP, a 19-question usability questionnaire based on 5 main design dimensions (content, information architecture, navigation, layout, and visual guidance). DEEP can be used to capture detailed usability feedback that more directly relates to specific aspects of design requirements.     

An Empirical Evaluation of the System Usability Scale

This article presents nearly 10 year's worth of System Usability Scale (SUS) data collected on numerous products in all phases of the development lifecycle. The SUS, developed by Brooke (1996) Brooke, J. 1996. “SUS: A “quick and dirty” usability scale”. In Usability evaluation in industry, Edited by: Jordan, P. W., Thomas, B. A. Weerdmeester and McClelland, I. L. 189–194. London: Taylor & Francis.  [Google Scholar], reflected a strong need in the usability community for a tool that could quickly and easily collect a user's subjective rating of a product's usability. The data in this study indicate that the SUS fulfills that need. Results from the analysis of this large number of SUS scores show that the SUS is a highly robust and versatile tool for usability professionals. The article presents these results and discusses their implications, describes nontraditional uses of the SUS, explains a proposed modification to the SUS to provide an adjective rating that correlates with a given score, and provides details of what constitutes an acceptable SUS score.     

CBID系统的可用性评估

本文采用用户测试法和用户调查法对CBID(Case Based Industrial Design)系统进行评估分析。通过对可用性评估结果的分析,进一步为CBID系统与ICAID系统可用性对比研究提供根据。     

基于多媒体的启发式计算机基础教学的实践与思考

本文深入讨论如何提高当代大学生计算机基础能力,并根据作者多年计算机基础教学的经验,探索如何在多媒体教学环境中对学生进行启发式教学。     

人机界面可用性测试与评估研究综述

介绍并评述人机界面可用性的定义、可用性测试与评估的指标及方法。学术界对于可用性的内涵已基本达成共识,但大多针对不同界面选取不同的测试与评估指标及权重,测试与评估方法也大都停留于主观评价,还未能深入探讨用户与系统交互过程中的内在心理机制。     

A Systematic and Generalizable Approach to the Heuristic Evaluation of User Interfaces

Heuristic evaluation is one of the most actively used techniques for analyzing usability, as it is quick and inexpensive. This technique is based on following a given set of heuristics, which are typically defined as broad rules of thumb. In this paper, we propose a systematic and generalizable approach to this type of evaluation based on using comprehensive taxonomies as a source for the heuristics. This approach contrasts with other typical approaches, such as following (or adapting) Jakob Nielsen’s heuristics or creating ad hoc heuristics (formally or informally). The usefulness of our approach is investigated in two ways. Firstly, we carry out an actual heuristic evaluation of a mobile app in this manner, which we describe in detail. Secondly, we compare our approach and Nielsen’s. Additionally, we identify some limitations in Nielsen’s heuristics and some inconsistencies between them and established usability models, including Nielsen’s own.     

使用概率规则文法评估人机界面可用性

提出一种在界面系统设计规约的基础上使用的可用性评估方法.首先使用有限状态自动机抽象界面系统设计,根据概率规则文法对有限状态自动机的状态转换概率进行预测;然后结合用户的熟练程度提出了界面可用性评估算法;最后讨论了一个手机界面的可用性计算实例.文中方法能够在界面系统生命周期的早期使用,以较早地对不同设计方案进行比较,降低开发风险.     

基于决策树算法的可用性评估平台的实现

可用性是体现产品质量和市场竞争力的重要因素,可用性评估可以考察软件的效率、有效性、用户满意度,该文研究开发的可用性评估平台为软件开发过程的可用性评估提供专家知识支持。为了使可用性评估平台根据已有知识向用户提供具有价值的建议,使用改进后的启发式归纳分类算法：ID3决策树算法。根据对已有知识的信息熵计算,建立多叉决策树,然后利用交互过程中用户选择的节点信息得到用户的知识分类,向用户提供知识建议。系统在交互过程中,通过层层深入的交互方式,不断引导用户进行思考,做出选择,细化知识内容,排除冗余信息影响,明确具体属性值,实现主动的智能交互。通过改进的ID3决策树算法配合分层交互的方法建立的可用性评估平台系统能够有效地帮助用户完成软件的可用性评估工作,受到用户的认可。     

Performance Evaluation of Direct Heuristic Dynamic Programming using Control-Theoretic Measures

Approximate dynamic programming (ADP) has been widely studied from several important perspectives: algorithm development, learning efficiency measured by success or failure statistics, convergence rate, and learning error bounds. Given that many learning benchmarks used in ADP or reinforcement learning studies are control problems, it is important and necessary to examine the learning controllers from a control-theoretic perspective. This paper makes use of direct heuristic dynamic programming (direct HDP) and three typical benchmark examples to introduce a unique analytical framework that can be applied to other learning control paradigms and other complex control problems. The sensitivity analysis and the linear quadratic regulator (LQR) design are used in the paper for two purposes: to quantify direct HDP performances and to provide guidance toward designing better learning controllers. The use of LQR however does not limit the direct HDP to be a learning controller that addresses nonlinear dynamic system control issues. Toward this end, applications of the direct HDP for nonlinear control problems beyond sensitivity analysis and the confines of LQR have been developed and compared whenever appropriate to an LQR design.     

A Measurement and Structural Model for Usability Evaluation of Shared Workspace Groupware

This study presents the development process of a set of questionnaire items to establish a measurement model for the usability of shared workspace groupware systems, which is suggested as a usability scale called SWUS, the Shared Workspace Usability Scale. Manifest variables and latent variables are based on the various dimensions of teamwork collated through the literature. A structural model was built on the measurement model. Models were evaluated through PLS-SEM methods. Data acquired on candidate questionnaire items from 398 international respondents who are users of five different online collaborative word processors was used for the model analysis. Of 37 candidate manifest variables, 22 were retained, which were measuring seven latent constructs: “3C Mechanisms,” “Grounding,” “Team Integration,” “Communication,” “Shared Access,” “Awareness,” and “Usability.” The data provided empirical evidence for the structural model based on these latent variables. The responses of the participants were not sensitive to differences between users in terms of gender and native language but showed sensitivity to age, experience with the evaluated software, and different shared workspace groupware evaluated in the study. Our structural model attempts to integrate several frameworks and models of usability for CSCW environments and provides empirical evidence for its reliability and validity based on subjective responses from users of shared workspace groupware.     

旅行商问题的近优解评价方法--浅析启发式算法的有效性

1引言 旅行商问题(Traveling Salesman Problem,TSP)的描述如下:给定N个城市,已知它们之间的距离矩阵,寻求一条经过所有城市一次且仅一次的最短Hamilton回路.TSP已被证明属于NP完全问题,由于启发式算法具有计算复杂性与算法所得近优解的"质量"折中性好的特点,它在TSP算法的研究中占有重要的地位[1],启发式算法的有效性表现在两方面:一是计算复杂性低,二是近优解"质量"高.启发式算法的上界收敛性,即准收敛性的研究是评价启发式算法的一个重要问题.本文以评价近优解为中心,通过总结、归纳已有方法,整理各种典型算法的评价结果,对现有方法的适用范围和评价结果的意义作了分析讨论,其结论对于改善现有算法以及评价新算法有一定的指导作用.启发式算法的准收敛性仍旧是一个正在研究中的问题.     

基于网络的产品可用性评价系统的设计与实现

随着科学技术的不断发展和产品智能化水平的不断提高,产品的可用性已是消费者决定是否购买产品的主要因素,因此,提高产品的可用性已成为提高产品竞争力的核心。如何保证设计的产品既符合用户的需求又方便易用,即可用性问题,成为必须不断深入研究的问题。论文将目前国内外企业针对界面设计的可用性理论引入到工业产品设计中,从产品设计的角度对工业产品的可用性评估原则、流程和方法进行了探讨性研究。     

Psychometric Evaluation of the PSSUQ Using Data from Five Years of Usability Studies

Factor analysis of Post Study System Usability Questionnaire (PSSUQ) data from 5 years of usability studies (with a heavy emphasis on speech dictation systems) indicated a 3-factor structure consistent with that initially described 10 years ago: factors for System Usefulness, Information Quality, and Interface Quality. Estimated reliabilities (ranging from .83-.96) were also consistent with earlier estimates. Analyses of variance indicated that variables such as the study, developer, stage of development, type of product, and type of evaluation significantly affected PSSUQ scores. Other variables, such as gender and completeness of responses to the questionnaire, did not. Norms derived from this data correlated strongly with norms derived from the original PSSUQ data. The similarity of psychometric properties between the original and this PSSUQ data, despite the passage of time and differences in the types of systems studied, provide evidence of significant generalizability for the questionnaire, supporting its use by practitioners for measuring participant satisfaction with the usability of tested systems.     

Development of a Weighted Heuristic for Website Evaluation for Older Adults

Older adults are the fastest growing population of Internet users. As websites acquire a greater number of older visitors, it is vital that they are designed with this demographic in mind. Older users typically have different user characteristics than younger users; they may have changes in perceptual abilities, motor skills, cognitive abilities, mental models, and confidence in the use of technology. This research documents the development of a new weighted heuristic measure for evaluating the usability of websites for older adults and its validation with performance testing. Results from a repeated measures analysis of variance indicated that websites with different heuristic classifications were significantly different with respect to performance metrics and System Usability Scale ratings. Conclusions point to the need for web design that takes into account preferences and abilities of older web users.     

基于日志分析的移动应用可用性综合评估体系的研究

移动应用已经成为人们日常生活中不可缺少的部分,可用性成为影响移动应用竞争力的主要因素,也是目前移动应用中一个突出问题。可用性是判断产品好坏的一个核心要素,如果一个产品的可用性评价得分很高,那么极有可能会为企业带来庞大的用户量,采用合适的方式变现就可以实现经济效益,因此如何提高产品的可用性对于企业来说极其重要。移动应用可用性评价的关键是建立一套合理、完善的评价指标体系。本文首先对常用的指标体系进行了比较分析,然后针对移动应用便携性的特点,提取本文所需要的指标与测度参数,建立移动应用的可用性指标体系,最后通过日志分析和数据挖掘等方法完成移动应用可用性的评价研究。     

Optimizing Heuristic Evaluation Process in E-Commerce: Use of the Taguchi Method

This article proposes a 3-dimensional (3D) vision-based ambient user interface as an interaction metaphor that exploits a user's personal space and its dynamic gestures. In human-computer interaction, to provide natural interactions with a system, a user interface should not be a bulky or complicated device. In this regard, the proposed ambient user interface utilizes an invisible personal space to remove cumbersome devices where the invisible personal space is virtually augmented through exploiting 3D vision techniques. For natural interactions with the user's dynamic gestures, the user of interest is extracted from the image sequences by the proposed user segmentation method. This method can retrieve 3D information from the segmented user image through 3D vision techniques and a multiview camera. With the retrieved 3D information of the user, a set of 3D boxes (SpaceSensor) can be constructed and augmented around the user; then the user can interact with the system by touching the augmented SpaceSensor. In the user's dynamic gesture tracking, the computational complexity of SpaceSensor is relatively lower than that of conventional 2-dimensional vision-based gesture tracking techniques, because the touched positions of SpaceSensor are tracked. According to the experimental results, the proposed ambient user interface can be applied to various systems that require real-time user's dynamic gestures for their interactions both in real and virtual environments.     

A Heuristic Approach to the Discovery of Macro-Operators

This paper describes a heuristic approach to the discovery of useful macro-operators (macros) in problem solving. The approach has been implemented in a program, MACLEARN, that has three parts: macro-proposer, static filter, and dynamic filter. Learning occurs during problem solving, so that performance improves in the course of a single problem trial. Primitive operators and macros are both represented within a uniform representational framework that is closed under composition. This means that new macros can be defined in terms of others, which leads to a definitional hierarchy. The representation also supports the transfer of macros to related problems. MACLEARN is embedded in a supporting system that carries out best-first search. Experiments in macro learning were conducted for two classes of problems: peg solitaire (generalized Hi-Q puzzle), and tile sliding (generalized Fifteen puzzle). The results indicate that MACLEARN'S filtering heuristics all improve search performance, sometimes dramatically. When the system was given practice on simpler training problems, it learned a set of macros that led to successful solutions of several much harder problems.