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To promote both quality and economy in the production of applications and their interactive interfaces, it is desirable to delay their mutual binding. The later the binding, the more separable the interface from its application. An ideally separated interface can factor tasks from a range of applications, can provide a level of independence from hardware I/O devices, and can be responsive to end-user requirements. Current interface systems base their separation on two different abstractions. In linguistic architectures, for example User Interface Management Systems in the Seeheim model, the dialogue or syntax of interaction is abstracted in a separate notation. In agent architectures like Toolkits, interactive devices, at various levels of complexity, are abstracted into a class or call hierarchy. This Thesis identifies an essential feature of the popular notion of direct manipulation: directness requires that the same object be used both for output and input. In practice this compromises the separation of both dialogue and devices. In addition, dialogue cannot usefully be abstracted from its application functionality, while device abstraction reduces the designer's expressive control by binding presentation style to application semantics. This Thesis proposes an alternative separation, based on the abstraction of the medium of interaction, together with a dedicated user agent which allows direct manipulation of the medium. This interactive medium is called the surface. The Thesis proposes two new models for the surface, the first of which has been implemented as Presenter, the second of which is an ideal design permitting document quality interfaces. The major contribution of the Thesis is a precise specification of an architecture (UMA), whereby a separated surface can preserve directness without binding in application semantics, and at the same time an application can express its semantics on the surface without needing to manage all the details of interaction. Thus UMA partitions interaction into Surface Interaction, and deep interaction. Surface Interaction factors a large portion of the task of maintaining a highly manipulable interface, and brings the roles of user and application designer closer.

In the context of knowledge management, the challenge for organizations is to convert individual human knowledge into structural capital so that the knowledge becomes persistent in the organization, making it more accessible and hence more usable. How to codify the knowledge of a workforce, including the tacit knowledge of experts, and how to apply that codified knowledge with success are unresolved issues. The conversion of individual knowledge into structural capital is of particular relevance in the field of design. Design is a complex activity that creates valuable knowledge. However, that knowledge is often implicit, unstructured, and embedded in procedures, methods, documentation, design artifacts, and of course in the minds of designers and other project stakeholders. In addition, design teams are often multidisciplinary and include experts who apply tacit knowledge to arrive at solutions. Design projects extend over time so that the risk of losing design knowledge increases. Information in itself is not knowledge for the purposes of structural capital. A user interface (UI) design specification for example, does not capture the knowledge used to create that design. The specification tells us what the artifact should be, but it does not tell us how the design came to be or why it is the way it is. Design rationale (DR) is a field of study surrounding the reasoning behind design decisions and the reasoning process that leads to the design of an artifact. The objective of creating a design rationale is to make the reasons for design decisions explicit. Design space analysis (DSA) is one perspective on design rationale that explores alternative design solutions and the assessment of each against design objectives. The rationale behind design decisions provides insight about the design knowledge that was applied and is therefore, of interest to the structural capital of organizations. Moreover, the process of making the rationale explicit is of interest to the domain of user interface design. The challenge for UI designers and the question addressed in this research is how to make the design rationale explicit and use it to effectively support the design process? The proposed solution is to conduct design space analysiS as part of the process of de.slgn. To. test this solution it is important to explore the implications of generating design rationale in practice and to explore whether DSA reflects the knowledge that expert deSigners apply. The "DSA study" demonstrated and examined the use of design space analysis by UI experts in a long-term, practical, design setting. The findings suggest that design space analysis supports communication and the reasoning process, and it provides context around past design decisions. It was also found that conducting design space analysis encourages designers to accumulate design ideas and develop an understanding of design problems in a systematic way. In addition, the study showed that designers are capable of producing and using the notation, but that the effort to conduct DSA is an obstacle to its use in practice. Conclusions are drawn that DSA can structure the reasoning aspect of design knowledge. The "design skills study" identified the skills that user interface experts apply in practice. The findings indicate that many of the skills of UI experts correspond to the skills that are emphasized by DSA. The study emphasized the pervasiveness and importance of the communication activity in design, as well as the role of reasoning in communication and decision making. The study also identified design activities that receive comparatively little attention from UI experts and design skills that may be comparatively poor. Conclusions are drawn that DSA reflects in part the knowledge that designers apply in practice. Findings from the above studies point to two approaches that maximize the positive effects of DSA and minimize the effort to conduct a design space analysis. I describe these approaches as coaching and heuristics. Informal evaluations indicate that coaching and heuristics warrant further investigation. The findings from each of the studies have implications for design space analysis. These are discussed around several themes: the tension between the processes of designing and structuring design knowledge, the trade-off in effort between structuring design knowledge and interpreting unstructured design knowledge, design knowledge and the complementary roles of communication and documentation, and DSA as it pertains to expert and novice designers. It is inevitable that where there are new findings and solutions there are also new questions to be explored. Several interesting questions raised by these investigations suggest an agenda for future work.

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The objective of the thesis is to introduce the reader to the topic of user interfaces and their design, to provide basic information about the concepts and methods used for the development of user interfaces. The author based the theoretical part of the work on a particular interface design approach - user centered design. The practical part applies selected methods that are described in the theoretical part, the optimization and design of a user interface for a specific application is described. The design process precedes an analysis of other competitive products, the identification of target groups of clients and their needs, the optimization of existing key processes, the development of existing functionalities and proposals for the implementation of new functionalities. Against this background, the author creates a web application interface design and associated mobile application designs. The end of the work deals with designing a model for payments as a system service and outlines possible further extensions of the system.

This study explored how individuals categorized on handedness (being left or right hand dominant) reacted to having the vertical scroll bar of a web browser relocated to the left side of the screen. The relocation of the vertical scroll bar served as an alternative to the relocation of the prominent left aligned main navigation menu for most websites. Fifteen participants were recruited for the study. Each participant interacted with two versions of a web site in a modified browser to complete a set of ten short tasks. Participants completed tasks by interacting with a traditional and non-traditional vertical browser alignment. Left and right-handed participants were determined to be strikingly different in operation. Vertical scroll relocation produced some interesting results and responses.

Visual search is an important component of many human-computer interactions and a critical task in a variety of domains. These include screening for prohibited items in x-ray imagery of luggage in airports, identifying anomalies in medical imagery, and looking for unusual activity and changes over time in satellite imagery. Unlike many other human-machine interface tasks where a small error rate is quite acceptable, a crucial element of visual search tasks in these application areas is that a single mistake can have catastrophic consequences. Thus, any improvements in technology, interfaces, or human processes that can be made to aid visual search would be invaluable in these safety critical areas. Furthermore, even when one does not consider consequential activities such as cancer screening and airport security, most human-computer interactions involve some search component, and the impact of even small improvements is magnified by a high frequency of use. This thesis explores how some of these issues affect individuals' and teams' ability to perform visual searching tasks. Considerations such as group size and display configuration are examined, as are novel interfaces that aid search on tabletop and wall displays. The overarching goal of this work is to provide system designers with immediately implementable advice and guidelines on how to improve their systems in respect to visual search and to outline further research in this critical area.

Visual search is an important component of many human-computer interactions and a critical task in a variety of domains. These include screening for prohibited items in x-ray imagery of luggage in airports, identifying anomalies in medical imagery, and looking for unusual activity and changes over time in satellite imagery. Unlike many other human-machine interface tasks where a small error rate is quite acceptable, a crucial element of visual search tasks in these application areas is that a single mistake can have catastrophic consequences. Thus, any improvements in technology, interfaces, or human processes that can be made to aid visual search would be invaluable in these safety critical areas. Furthermore, even when one does not consider consequential activities such as cancer screening and airport security, most human-computer interactions involve some search component, and the impact of even small improvements is magnified by a high frequency of use. This thesis explores how some of these issues affect individuals' and teams' ability to perform visual searching tasks. Considerations such as group size and display configuration are examined, as are novel interfaces that aid search on tabletop and wall displays. The overarching goal of this work is to provide system designers with immediately implementable advice and guidelines on how to improve their systems in respect to visual search and to outline further research in this critical area.

Background: Electronic prescribing systems are designed to aid in the complex process of prescribing by providing patient information and decision support at the point of care. Successful implementation and effectiveness depend on a variety of factors, including usability and user interface design, which influence how the information and decision support are relayed to users. Poorly designed systems have been found to be associated with medication errors. Methods: We conducted a factorial design study to investigate the impact of screen density, highlighting, and placement of information, on the accuracy of prescribing when using an e-prescribing system. Study sessions were held during clinical pharmacology educational rounds, where residents and medical students answered simulated prescribing scenarios presented on various e-prescribing system interface configurations. Assignment of prescribing scenarios to interface configurations and presentation order were randomized between study sessions. Participants were also asked about their preferences for specific user interface configurations. Results: A total of 66 participants completed 844 prescribing cases, with 583 (69%) cases answered correctly. The presence of highlighting was associated with correct prescribing decisions (p-value = 0.001), with 181 out of 250 (72.4%) prescribing scenarios answered correctly on interfaces with highlighting of key clinical information, as opposed to 156 out of 242 (64.5%) on interface configurations without. Low screen density and central placement of information were not found to be statistically significant predictors of prescribing accuracy. The presence of highlighting was the only factor that the majority of participants (80.3%) preferred, but no effect was found when comparing prescribing accuracy on preferred versus non-preferred interface configurations. Conclusions: The factorial design methodology developed is a novel approach for efficient and objective evaluation of multiple user interface design factors in one study. Evidence-based design and usability principles are needed to enhance the design and appropriate use of e-prescribing systems as usability problems continue to be one of the primary reasons for dissatisfaction and poor levels of adoption. / Thesis / Master of Science (MSc)