D2.1 Requirements and Specification - CORBYS

D2.1 Requirements and Specification
categories to reflect the priorities of the majority of users.
Next additional checks have to be done to flag up, for negotiation with the stakeholders, the possible
deletions, demotions, promotions and new additions of specific requirements to be consensually resolved into
the set of mandatory, desirable and optional requirements for a first prototype. The need for the following
refinement steps arises as a natural consequence of the fact that the users in stating their requirements can not
be expected to be either exhaustive or factor-in the technology, market and practice constraints (SoA, SoM,
SoP); the trends of which they are not necessarily expected to be fully aware. Further, users are expected to
articulate their own perceived requirements which may or may not be complete and may be incompatible with
other users’ requirements or project resources or in conflict with the technological and/or market imperatives
and trends.
Figure 7: Prioritisation process in UI-REF
Accordingly it will next be necessary to “factor-in” the influence of the push-pull forces and their dynamics
over the near to medium term to ensure that the target system to be delivered will represent the highest rate-ofreturn
on investment for all stakeholders in order to have the highest chance of take-up and widest diffusion,
usability and technology-policy-process interoperability and convergence potential given the current and
emergent technological and practice environment that it will have to integrate with i.e. it will be as scalable
and sustainable as possible. Such pull and push factors representing constraints and affordances invoked as
requirements filters and augmenters can be best understood by performing respectively a SoA, SoP and SoM
analysis, where the State-of-X is represented by the latest update on the state of current modus operandi, gaps,
and, available enabling and emergent innovations from the viewpoint of X.
Prioritisation in UI-REF is performed at several levels including stakeholder, intimate or non-intimate usagecontext-type,
specific usage-contexts within each type, usage-context implementation sequencing, usability
sensitive evaluation of system functionalities whose usability assessment is ranked and weighted so as to
reflect their priorities in the order of the most-deeply-valued needs of the user as prioritised per the UI-REF
requirements engineering process. Such prioritisation processes will use a variety of situated techniques as
appropriate to best suit particular users and their usage-contexts for example Nirvana, Ablation and Noah’s
Arc, virtual user, nested videos, Frequency-Purpose-Hurry (FPH)-based analysis of user specified needs and
thus the resulting UI-REF Effects-Side-Effects-Affects multi-dimensional impact prediction and evaluation
matrices.
19