HCI Unit 1 (1)

. . UNIT- I:. Interaction Paradigms: Computing Environments, Analysing Interaction Paradigms, Interaction Paradigms.

. . • HCI designers must consider a variety of factors: – what people want and expect, physical limitations and abilities people possess, --how information processing systems work, – what people find enjoyable and attractive. – Technical characteristics and limitations of the computer hardware and software must also be considered..

. .  Realize efficient and effective interactions for single users and groups..

. . Analysing Interaction Paradigms:. • 5W + H. The ―who, what, where, why, and how (5W+H) heuristic is a procedure that can be used to define and analyse existing interaction paradigms and spaces and explore the elements and objects with which the user interacts..

. . predictions, and nuclear explosion dynamics. Display, other then text, was produced on special and expensive devices such as plotters or customized CRTs..

. . . . ell phones .. Mobile devices can be connected to global positioning systems (GPS). These have touch screens and voice interaction to alleviate potential visual attention problems during driving..

. . paradigm as it facilitates the collaboration of engineering teams spread at different locations. Universities use CMC to facilitate e-learning and research, an example of this is the Research Collaboratory for Structural Bioinformatics (RCSB, 2005)..

. . Canada. In Psychology it has application for the treatment of phobias. VR is also used to implement Computer-aided design software used in systems as Cadence used for IC design..

. . These can then be subdivided into further stages, seven in all. The stages in 1. Establishing the goal. 2. Forming the intention. 3. Specifying the action sequence. 4. Executing the action. 5. Perceiving the system state. 6. Interpreting the system state. 7. Evaluating the system state with respect to the goals and intentions. It is liable to be imprecise and therefore needs to be translated into the more specific intention, and the actual actions that will reach the goal, before it can be executed by the user. The user perceives the new state of the system, after execution of the action sequence, and interprets it in terms of his expectations. If the system state reflects the user’s goal then the computer has done what he wanted and the interaction has been successful; otherwise the user must formulate a new goal and repeat the cycle. Norman uses this model of interaction to demonstrate why some interfaces cause problems to their users. He describes these in terms of the gulfs of execution and the gulfs of evaluation. The user and the system do not use the same terms to describe the domain and goals – remember that we called the language of the system the core language and the language of the user the task language. The gulf of execution is the difference between the user’s formulation of the actions to reach the goal and the actions allowed by the system. If the actions allowed by the system correspond to those intended by the user, the interaction will be effective. The interface should therefore aim to reduce this gulf. The gulf of evaluation is the distance between the physical presentation of the system state and the expectation of the user. If the user can readily evaluate the presentation in terms of his goal, the gulf of evaluation is small. The more effort that is required on the part of the user to interpret the presentation, the less effective the interaction. The interaction framework:.

. . concepts or features of the Output. It is then up to the User to observe the Output and assess the results of the interaction relative to the original goal, ending the evaluation phase and, hence, the interactive cycle. There are four main translations involved in the interaction: articulation, performance, presentation and observation..

. . operations that have to be performed can be mapped onto doing the same task with paper and pencil. A task-action mapping model would allow competent use of a system for a particular task, even though the user has no detailed knowledge of the system and how it works..

. . more graphical interfaces. In addition, Command-Line interfaces tend to be very flexible since commands can be created with multiple parameters that can be set and altered for multiple applications. It is also suitable for repetitive tasks such as the creation of batch files. However, it is more suitable for expert users since it can be frustrating for the novice user given its learning curve. It also has poor error handling and requires substantial training and memorization..

. . are used to capture information and proceed linearly instead of navigating a hierarchical structure. The use of form fill-in requires the use of design tools. Heim (2007) and Shneiderman & Plaisant (2005) mention the following advantages and disadvantages with the use of form fill-in:.

. . From the EEAC perspective, this style offers a wide range of possible intentions. Users usually have multiple options for specifying action sequences. However, the style can be overwhelming for novice users and provide multiple ways of executing action sequences..

. . 3D Environment:. The 3D interaction is natural to most users since it recreates the real-world that can be perceived in a 3D space. This interaction style is popular in computer games but it has the problem of being processor intensive. For this reason, 3D interfaces normally use information in vector based format in order to decrease file sizes and facilitate mathematical calculations required for 3D geometrical transformations used for interface navigation. The basic 3D transformations are scaling, translation and rotation..

. . are problems associated with this style and highlighted by Leventhal & Barnes (2007) and Shneiderman & Plaisant (2005) in the following list:.