Towards a practical method of user interface evaluation

This paper describes a practical method for evaluating the usability of human-computer interfaces. The paper specifies the requirements of such a method, and then outlines our work in developing a method to meet this specification. The method is based on the conduct of realistic tasks with an interactive system and the subsequent systematic elicitation of end-users' and designers' reactions to the interface using a criterion-based evaluation checklist.

Two practical examples are used to illustrate development of the method: (a) evaluation of a prototype production scheduling system, and (b) comparative assessment of the usability of three prototype user interfaces to a public-access database. The paper discusses some issues raised by the method and considers how it can be furthe developed.     

An examination of four user-based software evaluation methods

Usability has become an important factor in the design of interactive software. In the quest to develop usable software, user participation in the design and evaluation process has been advocated. Four methods; logged data, questionnaires, interviews, and verbal protocol analyses have been the prominent base evaluation methods used, sometimes being combined in an attempt to provide a comprehensive evaluation. However, little is known about the strengths and weaknesses of these methods. In this study, these four methods were used to evaluate three different software types (spreadsheet, word processor, and database) with 148 subjects participating. The data obtained enabled a number of conclusions to be drawn regarding the usefulness of the methods when used individually and in combination.     

Empirical Study on Collaborative Writing: What Do Co-authors Do, Use, and Like?

How do people work when they are collaborating to write a document? What kind of tools do they use and, in particular, do they resort to groupware for this task? Forty-one people filled out a questionnaire placed on the World Wide Web. In spite of the existence of specialized collaborative writing tools, most respondents reported using individual word processors and email as their main tools for writing joint documents. Respondents noted the importance of functions such as change tracking, version control, and synchronous work for collaborative writing tools. This study also confirmed the great variability that exists between collaborative writing projects, whether it be group membership, management, writing strategy, or scheduling issues.     

Prototype evaluation and redesign: structuring the design space through contextual techniques

This paper addresses the problems involved in the progress through evaluation and redesign from one interface prototype to the next stage of development. An approach is proposed based on situated action techniques for the early identification of user interface issues and their translation into design factors that lead to design improvements. The approach can be used within parallel prototyping or iterative development. Situated action is increasingly popular for the participative identification of user requirements for information systems and is usually implemented at an early stage in systems development. In contrast the most frequently used method for user participation within detailed interface design is within iterative user-based evaluation which is often performed relatively late in the development. The method described involves linking developer–user contextual evaluation sessions, where developers observe user's responses to an interactive prototype, and team evidence analysis sessions, where a group of designers work together to derive design decisions with the evidence collected from the users. The proposed method is tested in an experimental design. The proposed techniques provide a rich source of user evidence that can be brought to bear on the enhancement of prototype user interfaces. The study also showed how team working within a group of developers is important to effective design.     

基于知识的CSCW人机接口模型

人机接口是ＣＳＣＷ系统的重要组成部分，也是它的难点之一。本文针对ＣＳＣＷ系统中用主动作的协同特性，提出了一种协同人机接口结构模型ＫＣＨＣＩ，通过对用户动作的多层抽象和对动作结果的多层例化，实现多用户之间的多层次协同及感知，同时，以知识作为规范描述语言，不仅增强了接口的灵活性，提高了接口的协同效率，也方便了接口的开发。     

Ergonomic redesign and evaluation of a clamping tool handle

The handle of a commercial bar clamp was redesigned using ergonomic principles and then compared with an original clamp. Ten male and ten female students participated in simulated clamping tasks under various conditions, including different clamping heights, clamping methods, and handle-gripping methods, with respect to the dependent variables of clamping and handle-squeezing forces. The results showed that the redesigned clamp produced larger clamping force with lower handle-squeezing forces than the original clamp. As expected, males exerted more force than females in both clamping and squeezing forces. A pistol grip method was superior to an upside-down handle-gripping method. Two-handed operation was recommended for this type of clamp by simultaneously pulling the trigger and sliding the bar in order to initially tighten around objects. This study shows that the application of ergonomic guidelines increases the efficiency and usability of manual handtools.     

基于多点触摸的交互手势分析与设计*

提出了基于多点触摸的交互手势分析与设计方法。引入触摸手势元动作,采用接触面类型和状态及运动方式描述触摸手势,给出了简单触摸手势的统一描述框架,并提出了交互手势与交互任务的映射规则,将手势定义和手势意图联系起来。向交互设计者提供一种系统化和标准化的方法,提高了交互手势设计的通用性。     

Improving touchscreen keyboards: design issues and a comparison with other devices

The study explored touchscreen keyboards using high precision touch-screen strategies. Phase one evaluated three possible monitor positions: 30°, 45°, and 75° from horizontal. Results indicate that the 75° angle, approximately the standard monitor position, resulted in more fatigue and lower preference ratings. Phase two collected touch bias and key size data for the 30° angle. Subjects consistently touched below targets, and touched to the left of targets on either side of the screen. Using these data, a touchscreen keyboard was designed. Phase three compared this keyboard with a mouse-activated keyboard, and the standard QWERTY keyboard for typing relatively short strings of 6,19, and 44 characters. Results indicate that users can type approximately 25 words/minute (wpm) with the touchscreen keyboard, compared to 17 wpm using the mouse, and 58 wpm when using the keyboard. Possible improvements to touchscreen keyboards are suggested.     

Field evaluation of a prototype laser safety decision support system

A field evaluation of a decision support system prototype is described. The system is designed to aid the decision making of laser safety hazard assessors and laser manufacturers. The aims of the evaluation were to establish the usefulness and usability of the system, and to indicate where design changes might be needed. Three complementary methods namely observation evaluation, expert evaluation, and survey evaluation were used. Fifteen laser safety hazard assessors took part in the evaluation as subjects. Objective and subjective data were analysed and areas of user difficulty with the system were identified. The system was well-received although some pointers to modification for the eventual delivery system were identified. It is concluded that the aims of the evaluation were successfully met.     

Snap-on-handles for a non-powered hacksaw: An ergonomics evaluation,redesign and testing

In this study, we investigated how experienced and inexperienced subjects handle a box when it could be approached from any of its sides. Subjects moved a box (11 kg) either to a high (HS) or a low surface (LS). Wrist movements and grip force were synchronised and recorded, respectively, by electrogoniometers and an instrumented box. All subjects adopted a lateral-and-bottom grip, with parts of the hands simultaneously placed on the side and bottom of the box. This grip allowed the 50th percentile of wrist movements to be within safe limits, particularly in the sagittal plane. Low force was associated with lowering the box to LS and equally distributed but greater force when lifting to HS. Larger ulnar deviation was recorded when the box was lifted to HS. Only peak of wrist extension differentiated experienced from inexperienced subjects, with experienced presenting larger wrist extension. Alternative box designs are suggested to improve handling in real settings. PRACTITIONER SUMMARY: Understanding worker preferences for box lifting behaviour can contribute to the development of new designs that facilitate the adoption of more efficient postures while reducing the risk of upper-limb musculoskeletal disorders and promoting safer manual material handling.     

实时协同设计系统中同步过程的研究

作为一类支持人机交互的分布式系统,实时协同设计系统允许多个用户通过网络同步的对同一文档进行编辑.实时性、分布式、用户操作无限制是该系统的3个重要要求,但由于用户的同步操作和网络传输延迟的存在,协同过程中容易产生各种不同步的现象.对由于站点迟到或者非正常退出协同设计系统而引起的同步性问题进行了研究,提出了同步过程,包括主控站点发送同步队列、状态矢量轮询、缺少操作补齐等步骤,解决了站点迟到或非正常退出系统而引起的同步性问题.     

Ergonomics evaluation and redesign of a hospital meal cart

The ergonomic, design and other problems of a conventional hospital meal cart were evaluated with a view to redesign a hospital meal cart by incorporating ergonomic principles and data. The operators encountered difficulty in setting the cart in motion, seeing over the cart, turning the cart and stopping the cart while in motion. The operators expressed postural discomfort in the shoulder, neck, back, lower back, knee and leg, and ankle and foot. The cart with meal trays and food was found to exceed the acceptable initial turning push force requirement of 5th percentile females. Recommendations were made for proper placement of cart handles and handle diameter, provision of large-diameter cart wheel made of hard rubber tire, reduction of cart height, use of plastic material for cart construction, provision of emergency brake, provision of individually (electrically) heated plates for soup and main meal, provision of thick air-tight transparent plastic doors, and reduction of the meal tray size. Several recommendations were adopted by the manufacturer in the new model.     

人机交互中任务分析及任务建模方法综述

为了开发出具有高可用性的交互系统,需要准确地分析用户的任务,建立任务模型,并将其应用到系统开发的各个阶段.针对此问题,介绍了任务的相关概念,对典型的任务模型研究进行综述,分别从描述方式、描述能力、语法语义和任务之间的关系等方面进行比较,最后对任务分析和任务建模的发展趋势进行了讨论和展望.     

Negotiation in collaborative activity: an implementation experiment

An experiment is proposed which begins to systematically explore the potential contribution of discourse theory to the design of interactive systems. The experiment involves implementing and comparing two versions of a very simple system for planning air travel itineraries. One version of the system includes facilities based on discourse theory, and the other does not. Neither system uses natural language. The long-term goal of this research is to develop a toolkit that can be used to add discourse capabilities to any interactive system.     

User Attitudes Regarding a User-Adaptive eCommerce Web Site

Despite an abundance of recommendations by researchers and more recently by commercial enterprises for adaptive interaction techniques and technologies, there exists little experimental validation of the value of such approaches to users. We have conducted user studies focussed on the perceived value of a variety of personalization features for an eCommerce Web site for computing machinery sales and support. Our study results have implications for the design of user-adaptive applications. Interesting findings include unenthusiastic user attitudes toward system attempts to infer user needs, goals, or interests and to thereby provide user-specific adaptive content. Users also expressed equivocal opinions of collaborative filtering for the specific eCommerce scenarios we studied; thus personalization features popular in one eCommerce environment may not be effective or useful for other eCommerce domains. Users expressed their strong desire to have full and explicit control of data and interaction. Lastly, users want readily to be able to make sense of site behavior, that is, to understand a site’s rationale for displaying particular content.     

Implicit human computer interaction through context

In this paper the term implicit human-computer interaction is defined. It is discussed how the availability of processing power and advanced sensing technology can enable a shift in HCI from explicit interaction, such as direct manipulation GUIs, towards a more implicit interaction based on situational context. In the paper, an algorithm is given based on a number of questions to identify applications that can facilitate implicit interaction. An XML-based language to describe implicit HCI is proposed. The language uses contextual variables that can be grouped using different types of semantics as well as actions that are called by triggers. The term of perception is discussed and four basic approaches are identified that are useful when building context-aware applications. Two examples, a wearable context awareness component and a sensor-board, show how sensor-based perception can be implemented. It is also discussed how situational context can be exploited to improve input and output of mobile devices.     

Collaborative Writing Is Hard to Support: A Field Study of Collaborative Writing

This paper documents the results of a field test of Instant Update, a collaborative writing tool by a geographically dispersed department at the MITRE Corporation. Thirty-six participants were given Instant Update software and free training and support in exchange for their cooperation with data collection. These participants spent a great deal of time writing and communicating with each other about their written work. They began the pilot test with enthusiasm, using Instant Update for many types of documents and anticipating many benefits. After three months of experience they rated the actual benefits they received from the software lower than they had expected. Their usage became much more refined. They continued to use it for some types of documents, but stopped for others. The collaborative writing software was used successfully to create joint documents that have a consistent format and are produced on a regular basis (such as weekly activity reports) and for documents that provide access to shared information (such as a vacation calendar). It was used less successfully for the production of documents that require a complex work flow and have a changing group of contributors. We concluded that although collaborative writing is difficult to support and the currently available collaborative writing tools need to be improved before they can meet the needs of most co-writers, they are adequate for some types of tasks. Documents that are well defined and are created by experienced users who can cooperate well can benefit from the currently available tools.     

人机交互的自动钢琴伴奏系统的研究

针对基于隐马尔科夫模型(HMM)的算法而实现的作曲系统进行改进,提出了利用人机交互式的音乐伴奏音型选择方式,实现了使不具备音乐知识的使用者也可以创作出善心悦目的乐曲。系统的给出了人机交互式创作的原理以及理论支持,通过实验证明了人机交互系统的可行性。最后邀请了三位专业作曲家对改进后的伴奏结果进行了系统评估,评估认为,计算机作曲系统可以创作出大众喜欢的音乐作品。