28,238 research outputs found
A formal framework for the specification of interactive systems
We are primarily concerned with interactive systems whose behaviour is highly reliant on end
user activity. A framework for describing and synthesising such systems is developed. This
consists of a functional description of the capabilities of a system together with a means of
expressing its desired 'usability'. Previous work in this area has concentrated on capturing
'usability properties' in discrete mathematical models.
We propose notations for describing systems in a 'requirements' style and a 'specification'
style. The requirements style is based on a simple temporal logic and the specification style is
based on Lamport's Temporal Logic of Actions (TLA) [74]. System functionality is specified as
a collection of 'reactions', the temporal composition of which define the behaviour of the system.
By observing and analysing interactions it is possible to determine how 'well' a user performs
a given task. We argue that a 'usable' system is one that encourages users to perform their tasks
efficiently (i.e. to consistently perform their tasks well) hence a system in which users perform
their tasks well in a consistent manner is likely to be a usable system.
The use of a given functionality linked with different user interfaces then gives a means
by which interfaces (and other aspects) can be compared and suggests how they might be
harnessed to bias system use so as to encourage the desired user behaviour. Normalising across
different users anq different tasks moves us away from the discrete nature of reactions and
hence to comfortably describe the use of a system we employ probabilistic rather than discrete
mathematics.
We illustrate that framework with worked examples and propose an agenda for further work
Usability Evaluation in Virtual Environments: Classification and Comparison of Methods
Virtual environments (VEs) are a relatively new type of human-computer interface in which users perceive and act in a three-dimensional world. The designers of such systems cannot rely solely on design guidelines for traditional two-dimensional interfaces, so usability evaluation is crucial for VEs. We present an overview of VE usability evaluation. First, we discuss some of the issues that differentiate VE usability evaluation from evaluation of traditional user interfaces such as GUIs. We also present a review of VE evaluation methods currently in use, and discuss a simple classification space for VE usability evaluation methods. This classification space provides a structured means for comparing evaluation methods according to three key characteristics: involvement of representative users, context of evaluation, and types of results produced. To illustrate these concepts, we compare two existing evaluation approaches: testbed evaluation [Bowman, Johnson, & Hodges, 1999], and sequential evaluation [Gabbard, Hix, & Swan, 1999]. We conclude by presenting novel ways to effectively link these two approaches to VE usability evaluation
Usable Security: Why Do We Need It? How Do We Get It?
Security experts frequently refer to people as âthe weakest link in the chainâ of system
security. Famed hacker Kevin Mitnick revealed that he hardly ever cracked a password,
because it âwas easier to dupe people into revealing itâ by employing a range of social
engineering techniques. Often, such failures are attributed to usersâ carelessness and
ignorance. However, more enlightened researchers have pointed out that current security
tools are simply too complex for many users, and they have made efforts to improve
user interfaces to security tools. In this chapter, we aim to broaden the current perspective,
focusing on the usability of security tools (or products) and the process of designing
secure systems for the real-world context (the panorama) in which they have to operate.
Here we demonstrate how current human factors knowledge and user-centered design
principles can help security designers produce security solutions that are effective in practice
Technology Culture of Mobile Maintenance Men
Technology plays a major role in our life and the role is increasing as a result of fast technological development occurring all the time. Technologyâs impact on our everyday life sets new challenges also to designers. In order to design products which are usable. We need to understand technologies and devices we are developing, users of our designed products, and the relationships our users have with different kinds of technologies.
User-centred design (UCD) has emerged as a counter part for traditional technology centred product development. UCD emphasizes the role of the users in every phase of product design and development. However, it seems that the usersâ relationships with technologies is underestimated and sometimes even forgotten also in UCD. The usersâ current tools and technological environment is seen as just surroundings and task related tools instead of as an important factor that affects to usersâ actions and opinions.
This article presents a case study where mobile IT maintenance men where studied with traditional UCD methods and in addition the user research was deepened with focusing on usersâ relationships with technology. The results show that UCDâs methods can miss some critical phenomena relating to usersâ relationships with technology and affecting to usability and quality of the developed products.
Understanding how users comprehend the technologies they use, i.e. understanding what kind of technology culture the users are a part of, enables designers to better evaluate how well the developed product will fit in the lives of itâs users and what sorts of changes are possibly going to happen or required to happen in order the new product to be included in the usersâ technology culture. These kinds of evaluations help the designers to design better products and the companies to better estimate business risks relating to for example technology acceptance.
Keywords:
Technology Culture, User-Centred Design, User Research, Distributed and Mobile Work</p
Using GOMS to predict the usability of user interfaces of small off-the-shelf software products
The design of user interfaces and how usable they are, are both important research topics in computer science. This thesis is a research effort aimed at exploring the whole concept of usability and measuring the quality of a user interface in terms of how usable it is. Usability means how easy a system can be learned and used. In order to have usable products, they must be initially designed with usability in mind. A survey of methods for designing user interfaces which incorporate usability are outlined and they include some or all of the principles for designing for usability, proposed by various authors.
Evaluating the quality of existing interfaces can be done by various methods.The method used in this dissertation is the GOMS (goals, operators, methods and selection rules) approach. This model was initially proposed by [Card, Moran & Newell 83] and the approach is based on constructing an explicit model of the user's procedural knowledge, entailed by a particular system design. [Kieras & Poison 85] expanded this model to suggest that quantitive measures defined on this explicit representation of the user's knowledge can predict important aspects of usability. The predictions are obtained from a computer simulation model of the user's procedural knowledge that can actually execute the same tasks as the user.
To test the reliability and accuracy of the GOMS model predictions, the author carried out a pseudo-experiment on four inexperienced users using two different types of word-processors. The actual results from the experiment were compared with the GOMS predictions.The GOMS model was found to have some limitations and some enhancements to the approach are proposed. It was also found that the experiment had some limitations and improvements for a better experiment are proposed
Usability and Trust in Information Systems
The need for people to protect themselves and their assets is as old as humankind. People's physical safety and their possessions have always been at risk from deliberate attack or accidental damage. The advance of information technology means that many individuals, as well as corporations, have an additional range of physical (equipment) and electronic (data) assets that are at risk. Furthermore, the increased number and types of interactions in cyberspace has enabled new forms of attack on people and their possessions. Consider grooming of minors in chat-rooms, or Nigerian email cons: minors were targeted by paedophiles before the creation of chat-rooms, and Nigerian criminals sent the same letters by physical mail or fax before there was email. But the technology has decreased the cost of many types of attacks, or the degree of risk for the attackers. At the same time, cyberspace is still new to many people, which means they do not understand risks, or recognise the signs of an attack, as readily as they might in the physical world. The IT industry has developed a plethora of security mechanisms, which could be used to mitigate risks or make attacks significantly more difficult. Currently, many people are either not aware of these mechanisms, or are unable or unwilling or to use them. Security experts have taken to portraying people as "the weakest link" in their efforts to deploy effective security [e.g. Schneier, 2000]. However, recent research has revealed at least some of the problem may be that security mechanisms are hard to use, or be ineffective. The review summarises current research on the usability of security mechanisms, and discusses options for increasing their usability and effectiveness
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