Information Technology Reference
In-Depth Information
-
i
=1
..n
Space
i
is the set of
Spaces
defining the multilayered spatial struc-
ture of the MMASS;
-
i
=1
..|F |
F
i
denotes the set of
fields
acting in the MMASS;
-
i
=1
..|A|
A
i
denotes the set of
agents
situated in it.
Field emission-propagation-perception is the mechanism defined for asyn-
chronous interaction among agents situated in the same or different MASS's: an
agent emits a field that propagates throughout the
Space
and can be perceived
by other agents. In order to allow MASS interaction the MMASS model intro-
duces the notion of
interface
. The interface of a MASS specifies fields imported
from and exported into each MASS, and takes the following format:
Interface
(
MASS
i
,
export
:
E
;
import
:
I
)
where
E ⊂ F
i
and
I ⊂ F
i
are respectively the set of fields exported into and
imported from
MASS
i
. Imported fields are used in agent actions as internal
fields do. As will be better explained in section 2.3 and 2.4, they can be used in
the definition of agent perception function and mentioned in the specification of
agent actions. By definition, the value of an external field at any site of the local
Space
of a MASS is the value specified at its emission. Moreover, the receiving
MASS has to define if and how this value has to be internally propagated by
means of local fields defined for this purpose. In fact, their distribution function
(see section 2.2) is highly dependent on the structure of the local
Space
which is
completely hidden to external MASS's. In sections 2.1, 2.2, 2.3 each component
of a MASS will be described in more detail.
2.1 Spaces
The environment where the agents of a MASS are situated is named
Space
and
is defined as made up of a set
P
of sites arranged in a network. Each
site p ∈ P
can contain at most one agent and is defined by the 3-tuple
<a
p
,F
p
,P
p
>
where:
-
a
p
∈ A ∪ {⊥}
is the agent situated in
p
(
a
p
=
⊥
when no agent is situated
in
p
, that is
p
is empty);
-
F
p
⊂ F
is the set of fields active in
p
(
F
p
=
∅
when no field is active in
p
);
-
P
p
⊂ P
is the set of sites adjacent to
p
.
In this way the
Space
can be considered as an undirect graph of sites.
2.2 Fields
Fields acting within a MASS can be generated by agents of the MASS or have a
source outside the local
Space
in the case of fields imported from another MASS
