Information Technology Reference
In-Depth Information
Appendix A: Examples of Metrics with Their Generic Description
Name
Compactness (Cp)
Attribute
Appropriateness recognisability / Navigability / Interconnectivity.
Description
The degree of interconnection among nodes belonging to a hypermedia graph. Its
formula is Cp = (Max - ∑i ∑j Dij) / (Max - Min), where Max = (n2 - n)*k; Min =
(n2 - n); n = quantity of nodes in the graph; k = constant superior to the amount of
nodes; ∑i ∑j Dij = the sum of distances taken from the matrix of converted distances
(with factor k); and Dij = the distance between the nodes i and j.
Scale type
Ratio between 0 and 1.
Interpretation
Values closer to 1 signify that each node can easily reach any other node in the
graph. However, a fully connected graph may lead to disorientation.
Application
level
At the PIM/PSM level, if navigation is modeled as a graph where nodes represent
pages and edges are links among pages; and at the CM level by analyzing the link's
targets included in the source code for each page.
Name
Discernible links (DL)
Attribute
Appropriateness recognisability / Navigability / Clickability.
Description
The degree to which links are discernible from other textual elements. Its formula is
DL = 1 - 0.5(CL / NL + CT / NT), where CL = the number of links that may be
confused with textual elements; NL= total number of links; CT = number of textual
elements that may be confused with links; and NT = total number of textual ele-
ments.
Scale type
Ratio between 0 and 1.
Interpretation
Values closer to 1 indicate that users can differentiate links from textual elements.
Application
level
At the PIM/PSM level, if the expressiveness of abstract user interface models allows
aesthetic properties to be defined for links such as color or style; and at the CM level
by assessing the elements from the source code that define the visual appearance of
links in the final user interface (e.g., Cascading Style Sheets).
Appendix B: Examples of Operationalized Metrics for OO-H
Compactness (Cp)
: In an OO-H navigational model, the compactness is calculated by
considering the navigational classes and links of each NAD as a hypermedia graph in
which classes are nodes and links are edges. If we consider the scale type and the
recommendations suggested by Botafogo
et al.
[5], then the rating levels are estab-
lished as no UP (0.2 < x ≤ 0.8), and medium UP (0 ≤ x < 0.2 and 0.8 < x ≤1).
Discernible links (DL)
: In an OO-H presentation model, the visual properties of tex-
tual elements in each APD (i.e., links and labels) are represented as attributes such as
font, color, and face. The operationalized metric is:
DL (APD) = 1 - 0.5(CLi / NTLi + CLa / NTLa)
where
CLi
signifies the number of links with similar visual properties to most of the
labels,
CLa
signifies the number of labels with similar visual properties to most of the
links, whereas
NTLi
and
NTLa
signify the total number of links and labels, respec-
tively. If we consider the scale type, then the rating levels are established as no UP
(0.99 < x ≤ 1), low UP (0.7 < x ≤ 0.99), medium UP (0.5 < x ≤ 0.7), and critical UP (0
< x ≤ 0.5).
