Adapting Medical Content to the Terminal Capabilities of Wireless Devices - E-Healthcare Systems and Wireless Communications - page 295

of Nokia cell phones are stored in a profile reposi-
tory maintained by Nokia itself.
The URL that points to the UAProf of a wire-
less device can be found in the metadata (headers)
of the HTTP requests sent by the wireless device.
Normally, the URL is located in the X -wap-profile
or the Profile or the Options header. For example,
the value of the X-wap-profile header generated
by a Nokia 6230i cell phone can be:

developers to describe the relationship between
different elements of a Digital Item. DIDs can be
constructed using the Digital Item Declaration
Language (DIDL) (ISO/IEC 21000-2:2003). In-
teractions concerning Digital Items are represented
in DIDL at both client and server sides: both the
application part and the user environment can be
described in DIDL.
As far as it concerns the capabilities of the
client device, the MPEG 21 framework provides
wide flexibility since it is comprised of tools
adequate to describe not only the terminal capa-
bilities but the whole usage environment of the
client, including the user preferences (general and
specific), the device's network characteristics and,
finally, the natural environment's characteristics
(including location and mobility). With respect
to the hardware part of terminal capabilities, the
MPEG-21 DIA defines components related to the
Codec Capabilities, the Input Output Capabili-
ties, the Display Capabilities, the Audio Output
Capabilities, the User Interaction Input Support,
the Device Property, the Power Characteristics
and the Storage Characteristics. Exhibit 2 shows
the use of the DIA InputOutputCapabilities de-
scription tool.
Although the MPEG-21 framework does not
specify relations to existing technologies for the
transport mechanisms of DIDL declarations, the
usage of HTTP headers, similar to the CC/PP
mechanism, is opted. To this end, the Profile or
the Options header can be used for transmitting
the DIA DIDL descriptions.

X-wap-profile: http://nds1.nds.nokia.
com/uaprof/N6230ir200.xml

This URI enables the server to retrieve the
UAProf file from the corresponding Profile Re-
pository Server that holds it, so parsing it, to be
informed of the full set of capabilities of its client
device and to respond with content and data in
format that wouldn't show corrupt or deficient.

MPEG-21

The MPEG-21 standard (MPEG-21 home page),
from the Moving Picture Experts Group (MPEG
home page), aims at defining an open framework
for multimedia applications. Within its objectives
is to enable universal multimedia access on any
device and on any network facilitating the ap-
plication and content adaptation based on usage
environment (or user context). At its most basic
level, the MPEG-21 provides a framework in
which one user interacts with another one, and the
object of that interaction concerns a Digital Item,
a fundamental unit of distribution and transaction.
MPEG-21 consists of several standards.
Among them, the MPEG-21 DIA (Digital Item
Adaptation) (ISO/IEC 21000-7:2004) is used to
describe the usage environment and constraints,
as well as the user preferences and resource ad-
aptation policies. On the other side, the Digital
Item Declaration (DID) (ISO/IEC 21000-2:2003)
provides the required flexibility for declaring
Digital Items composed of multiple multimedia
resources. DID is a XML container allowing

Towards Ubiquitous
Service Provision

Reading the value of an HTTP header is not diffi-
cult. What is required is just the use of a server-side
CGI (Common Gateway Interface) scripting tech-
nology to write a few lines of code. The common
scripting languages to this end include ASP, Java
Servlet / JSP, Perl and PHP. In our implementation
we have chosen to develop a Java Servlet (Jason