Database Reference
In-Depth Information
“it makes one stop in a place of kind EatingPlace” can be satisfied in any order.
On the opposite, the following would be a sequence behavior:
Tourist2 behavior
: A daily trajectory shows the Tourist2 behavior if:
its Begin point P1 is a place of kind “Accommodation,” it makes at
least one stop in a in a place of kind “Museum” or “TouristAttrac-
tion,” later it makes one stop in a in a place of kind “EatingPlace,”
and its End point is in the same P1 place as its Begin point.
Chapters
6
and
7
present data-mining methods for searching sequence behav-
iors. Chapter
12
presents a query language for searching complex behaviors
containing generic temporal constraints.
1.6 Conclusions
In order to introduce the reader to the broad spectrum of concerns that are dis-
cussed in detail in the rest of the topic, this chapter has aimed at providing a
consistent vision of the trajectory domain. We have defined the basic concepts
that underline trajectory management, emphasizing aspects related to various
representations of trajectories. Secondly, we have shown how trajectory behav-
iors can be precisely described by predicates involving movement attributes
and/or relationships to the context and/or semantic annotations.
While earlier research mainly focused on processing the raw data received
from sensors, GPS devices and the like, recent research rather focuses on meth-
ods to enrich a movement track with more semantic, application-oriented infor-
mation. Semantic additions enable new capabilities of running far-reaching
analyses of mobility-related phenomena, thus conveying a huge potential for all
kinds of innovative applications. As each application may have its own view of
its trajectories, such as a discrete, continuous, or semantic view, we have defined
three kinds of trajectory representations that can be superimposed.
In a broader perspective, several complementary types of movement remain
to be investigated, including movement of large and deforming objects (e.g., oil
spills, diseases), constrained movements (e.g., cars, trains that are constrained
by a network), or more aggregated representations of movement, such as flows.
After choosing the representation of the movement best fitted for the appli-
cation, frequently the major focus is to understand the behaviors of the moving
objects. Understanding why and how people and animals move, which places
they visit and for which purposes, what their activities are, and which resources
they use is of tantamount importance for many kinds of decision makers, in
particular public authorities in charge of managing societal resources.
At the core of behavioral analysis is identifying which characteristics of the
moving objects define which behaviors. In the simplest case, experts define
