Notes

Abstract

"Mobility coupled with the development of a wide variety of access devices has engendered new requirements for HCI such as the ability of user interfaces (UIs) to adapt to different contexts of use. We define a context of use as the set of values of variables that characterize the computational device(s) used for interacting with the system as well as the physical and social environment where the interaction takes place. A UI is plastic if it is able to adapt to context changes while preserving usability." (p.1)

"Keywords Human computer interaction, plasticity, adaptation, context of use, platform, environment, engineering, reference framework." (p.1)

"Although principles of user-centered design methods and modeling techniques [19] offer a sound substrate, pervasive computing opens the way to new challenging requirements. In particular, people want to have the choice. They want to be able to choose among a wide range of software platforms and hardware devices to accommodate multiple needs depending on places and spaces across time. Providing different interfaces specially crafted for each type of device and modality combination is extremely costly and could result in users having many different versions of interfaces on different devices. The impact includes massive under-use of interfaces potential and excessive development costs to maintain versions consistent across multiple platforms. The notion of plasticity to cope with these problems is introduced [23,24].(p.1)

About Placticity

"The term “plasticity” is inspired from the property of materials that expand and contract under natural constraints without breaking, thus preserving continuous usage. Applied to HCI, plasticity is the capacity of an interactive system to withstand variations of context of use while preserving usability. A context of use for a plastic system covers two classes of attributes: The attributes of the physical and software platform(s) used for interacting with the system. Typically, screen size and network bandwidth have an impact on the amount and modality of information to be rendered and transferred;
The environmental attributes that describe the physical surroundings of the interaction. These include the set of objects, persons and events that are peripheral to the current task(s) but that may have an impact on the system and/or the user's behavior, either now or in the future. Typically, light conditions may influence the robustness of a computer vision-based tracking system, noisy environments may eliminate sonic feedback, etc. At the task level, location in space provides context for information relevance; tasks that are central in the office (e.g., writing a paper) may become secondary in a train, etc." (p.1)

"A plastic user interface preserves usability if the properties selected at design time to measure its usability are kept within a range of values as adaptation occurs to contextual changes." (p.1)

"Activity theory takes into account the situation of action early in the design process. Unfortunately, situationdependent information is lost in the development process due to the lack of appropriate notations of the design and development tools. As a result, current tools implicitly assume that users are working with a desktop computer located at a specific place." (p.2)

"The Platform Model and the Environment Model define the contexts of use intended by the designers. For example, the size of the screen would be described in a platform model, whereas the level of noise of a room would be captured in an environment model." (p.3)