Information Technology Reference
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containing all information (resources and links
between them) about the users: the
set of all user
concepts UC
Example: User links can be subscriptions to
other users, or grouping of users, etc. Adding a
subscription link between two generic user models,
one containing a user's knowledge and interest,
and another one containing a user's knowledge
and availability, for instance, means that in the
target design system, a specific user belonging to
the first user category can be linked to the second.
For instance, a user with low knowledge and high
interest can subscribe to a user with high knowl-
edge and availability set to true. The thresholds
for what represents high and low knowledge,
etc., can be set as user model concept attributes,
as defined in Definition 24.
Definition 23:
A
user model attribute
ua
⊆
C
, the
set of all links between
users UL
L,
and the
set of all attributes de-
scribing users UA
⊆
A
.
Definition 20:
A
user map
UM
⊆
UM
of the
social adaptive system (SAS) is determined by the
tuple <
UC, UL, UA
>, where
UC
∈
UC
is a set of
⊆
user concepts,
UL
UL
is a set of links between
⊆
users and
UA
UA
is a set of optional user attri-
butes, which describe the user model in general.
Example: The set of attributes can include
knowledge level, interest, display preferences,
age, etc. Links within user models could appear
if, for example, an attribute such as interest can
be related, via a formula, to the knowledge level
of the user (this is not currently implemented in
the example system).
Definition 21:
A
user concept
(or, simply,
generic user
) uc
⊆
UA
of a user model map is a tuple <UM, type,
val> where UM. is the user map the user model
attribute belongs to, type is the name of the user
map attribute, and val is the value (contents) of
the user model attribute.
Example: A user map would map all generic
user types that can appear in a social adaptive
system (learner, teacher, etc.). At this level, at-
tributes could represent the number of teachers
or of learners the application overall allows for,
or the type of groups allowed.
Definition 24.
A
user model concept attribute
ua2
∈
UC
is defined by the tuple
<UM
uc
, UA
uc
,
UL
uc
> where UM
uc
∈
UM
is the
module the generic user is supposed to study,
UA
uc
∈
UA
is a set of UM concept attributes,
and
UL
uc
∈
UL
is a set of user links the user is
participating in.
Example: A user of the social adaptive system
could be represented by their set of preferences,
such as knowledge, interest, etc., and could also
be related to other users via various relations, such
as friendship or class membership. The generic
user (or user model) stores the type of attributes
that are used for a given module. E.g., it stores the
fact that a user's knowledge and age is important,
that the knowledge default value is 0, and that the
age default value is 30. Please note that this does
not
represent user Jonny, who has a knowledge
of 79 and age of 44, which would be an instance
of this generic user.
Definition 22:
A
user model link
ul
⊆
UA
is a tuple <id
uc
,
type, val> where id
uc
is
an
identifier
for user uc
∈
UC
, type is the name
of the user model attribute; and val is the value
(contents) of the user model concept attribute; val
can also take the form <type, val>, to allow for
more complex, nested attributes.
Example: In the previous example, each at-
tribute can be represented as having the follow-
ing default values: knowledge level = beginner,
interest = 1, display preference = text and images,
age = 40. Note that at this modelling level, only
generic users are modelled, not actual users (e.g.
any user with knowledge level beginner, but not
the user Johnny, who also happens to be a begin-
ner). Instances of these attributes can be used
to represent the fact that Sara and Jessica are
∈
UL
is
∈
a tuple <
S
,
E, W, L
> with
S
,
E
),
respectively,
start
and
end
sets of user model
concepts,
W
a set of weights describing the link,
and
L
a set of labels describing the link.
⊆
UC
,
(
S, E
≠
∅
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