Systematic evaluation of design choices for software development tools

[Abstract]: Most design and evaluation of software tools is based on the intuition and experience of the designers. Software tool designers consider themselves typical users of the tools that they build and tend to subjectively evaluate their products rather than objectively evaluate them using established usability methods. This subjective approach is inadequate if the quality of software tools is to improve and the use of more systematic methods is advocated. This paper summarises a sequence of studies that show how user interface design choices for software development tools can be evaluated using established usability engineering techniques. The techniques used included guideline review, predictive modelling and experimental studies with users

Towards intelligent, adaptive input devices for users with physical disabilities

This thesis presents a novel application of user modelling, the domain of interest being the physical abilities of the user of a computer input device. Specifically, it describes a model which identifies aspects of keyboard use with which the user has difficulty. The model is based on data gathered in an empirical study of keyboard and mouse use by people with and without motor disabilities. In this study, many common input errors due to physical inaccuracies in using keyboards and mice were observed. For the majority of these errors, there exist keyboard or mouse configuration facilities intended to reduce or eliminate them. While such facilities are now integrated into the majority of modem operating systems, there is little published data describing their effect on keyboard or mouse usability. This thesis offers evidence that they can be extremely useful, even essential, but that further research and interface development are required. This thesis presents a user model which focuses on four of the most commonly observed keyboard difficulties. The model also makes recommendations for settings for three keyboard configuration facilities, each of which tackle one of these specific difficulties. As a user modelling task, this application presents a number of interesting challenges. Different users will have very different configuration requirements, and the requirements of individual users may also change over long or short periods of time. Some users will have cognitive impairments. Users may have very limited time and energy to devote to computer use. In response, this research has investigated the extent to which it is possible to model users without interrupting the task for which they are using a computer in the first place. This approach is appealing because it does not require users to spend time participating in model instantiation. This focus on inference rather than explicit testing or questioning also allows the model to dynamically track an individual user's changing requirements. This thesis shows that within the context of the keyboard difficulties studied, such an approach is feasible. The implemented model records users' keyboard input unintrusiveiy as they perform their own input tasks. This input is examined for evidence of certain types of input error or indications of difficulties in using the keyboard. In the model presented, conclusions are based on the assumption that the user is typing English text in a word processing application. However, the design of the model allows any other textual language to be used. A second empirical study, evaluating the model, is described. The model is shown to be very accurate in identifying users having difficulties in each of the areas tackled, the only exception being those who find a given operation awkward, but are able to perform it accurately. Where it is also possible to evaluate the configuration recommendations made by the model, the chosen settings are effective in reducing input errors and increasing user satisfaction with the keyboard. The model is also able to draw conclusions quickly for users with higher error rates, and shows good overall stability. In the light of this successful identification of keyboard difficulties, potential applications of the model are suggested. It could be used to help occupational therapists and assistive technologists to assess the keyboard configuration requirements of a new user. It could also be made available to users themselves - many people are currently unaware of facilities they may find useful, and how to activate them. The model could be extended to other areas of keyboard use, and to other input devices. This would allow systems to provide automatic, dynamic support for configuration, which would go some way towards improving the accessibility of computer systems for people with motor disabilities

Digital Image Access & Retrieval

The 33th Annual Clinic on Library Applications of Data Processing, held at the University of Illinois at Urbana-Champaign in March of 1996, addressed the theme of "Digital Image Access & Retrieval." The papers from this conference cover a wide range of topics concerning digital imaging technology for visual resource collections. Papers covered three general areas: (1) systems, planning, and implementation; (2) automatic and semi-automatic indexing; and (3) preservation with the bulk of the conference focusing on indexing and retrieval.published or submitted for publicatio

Freeform User Interfaces for Graphical Computing

報告番号: 甲15222 ; 学位授与年月日: 2000-03-29 ; 学位の種別: 課程博士 ; 学位の種類: 博士(工学) ; 学位記番号: 博工第4717号 ; 研究科・専攻: 工学系研究科情報工学専

Rehearsal: A Configuration Verification Tool for Puppet

Large-scale data centers and cloud computing have turned system configuration into a challenging problem. Several widely-publicized outages have been blamed not on software bugs, but on configuration bugs. To cope, thousands of organizations use system configuration languages to manage their computing infrastructure. Of these, Puppet is the most widely used with thousands of paying customers and many more open-source users. The heart of Puppet is a domain-specific language that describes the state of a system. Puppet already performs some basic static checks, but they only prevent a narrow range of errors. Furthermore, testing is ineffective because many errors are only triggered under specific machine states that are difficult to predict and reproduce. With several examples, we show that a key problem with Puppet is that configurations can be non-deterministic. This paper presents Rehearsal, a verification tool for Puppet configurations. Rehearsal implements a sound, complete, and scalable determinacy analysis for Puppet. To develop it, we (1) present a formal semantics for Puppet, (2) use several analyses to shrink our models to a tractable size, and (3) frame determinism-checking as decidable formulas for an SMT solver. Rehearsal then leverages the determinacy analysis to check other important properties, such as idempotency. Finally, we apply Rehearsal to several real-world Puppet configurations.Comment: In proceedings of ACM SIGPLAN Conference on Programming Language Design and Implementation (PLDI) 201

Text entry, analysis and correction help : assisting the disabled computer user with data entry

It was suggested several decades ago that computers would be the single biggest step forward in integrating people with physical disabilities into "normal" society. At that stage, much work was done in writing software and designing hardware that allowed computer operators with disabilities to use packages effectively, in certain cases as efficiently as people without disabilities. Since those days, judging by the lack of references on this subject the interest in dealing with disabled people has waned. It is only very recently that the spotlight has been focused on these potentially very productive persons. Unfortunately, the backlog is large and most existing applications software offers little or no support for users with disabilities. In this thesis, I have examined some of the hardware and software limitations of current desktop computer technology, focusing on the IBM PC and compatibles. I have also written a computer program that attempts to relieve some of the difficulties faced by a limited number of disabled users. In evaluating the results, I considered it important to relate the ensuing data with the real problems faced by a far wider spectrum of users than I attempted to cater for with the program and to suggest ways in which software products could be made to have wider applicability in the future

Machine aided indexing from natural language text

The NASA Lexical Dictionary (NLD) Machine Aided Indexing (MAI) system was designed to (1) reuse the indexing of the Defense Technical Information Center (DTIC); (2) reuse the indexing of the Department of Energy (DOE); and (3) reduce the time required for original indexing. This was done by automatically generating appropriate NASA thesaurus terms from either the other agency's index terms, or, for original indexing, from document titles and abstracts. The NASA STI Program staff devised two different ways to generate thesaurus terms from text. The first group of programs identified noun phrases by a parsing method that allowed for conjunctions and certain prepositions, on the assumption that indexable concepts are found in such phrases. Results were not always satisfactory, and it was noted that indexable concepts often occurred outside of noun phrases. The first method also proved to be too slow for the ultimate goal of interactive (online) MAI. The second group of programs used the knowledge base (KB), word proximity, and frequency of word and phrase occurrence to identify indexable concepts. Both methods are described and illustrated. Online MAI has been achieved, as well as several spinoff benefits, which are also described

Understanding Adoption Barriers to Dwell-Free Eye-Typing: Design Implications from a Qualitative Deployment Study and Computational Simulations

Eye-typing is a slow and cumbersome text entry method typically used by individuals with no other practical means of communication. As an alternative, prior HCI research has proposed dwell-free eye-typing as a potential improvement that eliminates time-consuming and distracting dwell-timeouts. However, it is rare that such research ideas are translated into working products. This paper reports on a qualitative deployment study of a product that was developed to allow users access to a dwell-free eye-typing research solution. This allowed us to understand how such a research solution would work in practice, as part of users\u27 current communication solutions in their own homes. Based on interviews and observations, we discuss a number of design issues that currently act as barriers preventing widespread adoption of dwell-free eye-typing. The study findings are complemented with computational simulations in a range of conditions that were inspired by the findings in the deployment study. These simulations serve to both contextualize the qualitative findings and to explore quantitative implications of possible interface redesigns. The combined analysis gives rise to a set of design implications for enabling wider adoption of dwell-free eye-typing in practice

Empirical Studies of Novices Learning Programming

This thesis is concerned with the problems that novices have in learning to program: in particular it is concerned with the difficulties experienced by novices learning at a distance, using instructional materials which have been designed especially for novices. One of the major problems for novices is how to link the new information which they encounter with their existing knowledge. Du Boulay, O'Shea and Monk (1981) suggest helping novices to bridge the gap between their existing knowledge and new information by teaching via a conceptual model, which serves to explain the new information in familiar terms.In this thesis the difficulties which novices have when learning to program with the help of a conceptual model were investigated. The curricula and conceptual models of four different programming languages are examined, all of which were designed to teach novices. Du Boulay, O'Shea and Monk (1981) have suggested criteria for analysing conceptual models. It is argued that these criteria, however, do not address the presentation of the conceptual model, and so are insufficient to evaluate them. An additional form of analysis was proposed and used, in addition to the criteria offered by Du Boulay et al. This is a way of describing the conceptual model which distinguishes three views of the conceptual model: state, procedure and function, and which highlights the different aspects which are important for the novice learner by identifying the different kinds of knowledge which are necessary to understand the conceptual model. This analysis of the conceptual models showed that the environments are not as exemplary as the du Boulay et al's criteria suggest, and indicated that three of the environments, SOLO, PT501 and DESMOND, lack a functional representation, and that the fourth, Open Logo, has other different problems.An empirical study was carried out to study the transfer effects of learning two of the languages, a high level and a low level language, sequentially. There was no evidence for such transfer effects. The difficulties novices have in learning the four different languages were also investigated. These studies show that even though the novices were studying environments designed for novices learning at a distance, they did not develop good levels of competence, and the problems they had fall into two main categories: programming and pedagogical.Although the different languages had different aims and curricula, novices had some problems which were common to all or most of the languages. These included understanding flow of control, developing and using programming plans, developing accurate mental models, and in the high level languages, understanding recursion. It is argued that some of these problems are related to the conceptual models. In particular, the difficulties novices had in developing and using plan knowledge, which is one of their main problems, can be explained by the lack of an appropriate functional description in the languages.The subjects' pedagogical problems arose from the relationship between the style and structure of the curriculum, its content, and the subjects themselves. In all the four texts the teaching material is very carefully structured and it is suggested that this may encourage the learner to adopt an over-dependent attitude towards the text, and in some cases, to work at an inappropriate syntactic level.The relationship between the distance learning situation and the novice programmer is discussed, and recommendations are made for improving the curricula used for teaching novices programming