Information Technology Reference
In-Depth Information
As the middleware is concerned with the context-awareness and adaptability aspects, it is
important to clarify these concepts. Within our development approach, Dey's definition
[Dey,2000] was adopted, according to which "context is any information that can be used to
characterize the situation at an entity". An entity could be a person, place, or object that is
considered relevant to the interaction between a user and an application, including the user
and applications themselves. Context could be of different type, e.g. location, identity,
activity, time.
Dey's definition is utilized here as a basis for further discussions. In order to elaborate on
this definition a working one for the creation of the desired middleware architecture, we
first solidify the definition as presented further in the chapter. We want clearly to
differentiate context-awareness from the adaptability. Context-awareness is the
middleware's ability to identify the changes in the environment/context as regards:
Mobile device's location (
device mobility
) - in some cases this mobility leads to changing
the serving InfoStation. This is especially important due to the inherent mobility within
the system, as users move throughout the University campus. This information has a
bearing on the local services deployed within a particular area i.e. within the University
Library;
User device (
user mobility
) - this mobility offers different options for the delivery of the
service request's results back to the user. What is important here is to know the
capabilities of the new device activated by the user, so as to adapt the service content
accordingly;
Communication type - depending on the current prevailing wireless network
conditions/constraints, the user may avail of different communications possibilities
(e.g. Bluetooth or WiFi);
User preferences - service personalisation may be needed as to reflect the changes made
by users in their preferences, e.g., the way the service content is visualised to them, etc.;
Goal-driven sequencing of tasks engaged in by the user;
Environmental context issues such as classmates and/or learner/educator interactions.
The goal of adaptability is to ensure trouble-free, transparent and adequate fulfilment of
user requests for services by taking into account the various aspects of the context
mentioned above. In other words, after identifying a particular change in the service
environment, the middleware must be able to take compensating actions (counter-measures)
such as handover of user service sessions from one InfoStation to another, re-
formatting/transcoding of service content due to a change of mobile device (varying device
capabilities), service personalisation, etc.
To ensure adequate support for user mobility and device mobility (the first two aspects of
the context change), the following four main communications scenarios are identified for
support in our middleware architecture [Ganchev,2008b]:
'No change'
- a mLearning service is provided within the range of the same InfoStation
and without changing the user mobile device;
'Change of user mobile device'
- due to the inherent mobility, it is entirely possible that
during an mLearning service session, the user may shift to another mobile device, e.g.
with greater capabilities, in order to experience a much richer service environment and
utilize a wider range of resources;
