Adapting Medical Content to the Terminal Capabilities of Wireless Devices - E-Healthcare Systems and Wireless Communications - page 302

Table 1. Group: display

Capability Name Type Description

resolution_width any integer number This field represents the screen width expressed in pixels

resolution_height any integer number This field represents the screen height expressed in pixels

Columns any integer number Number of columns presented

Rows any integer number Number of lines presented

max_image_width any integer number Width of the images viewable (usable) width expressed

in pixels. This capability refers to the image when used in
“mobile mode”, i.e. when the page is served as XHTML MP,
or it uses meta-tags such as “viewport”, “handheldfriendly”,
“mobileoptimised” to disable “web rendering” and force a
mobile user-experience (for example, iPhone 4 can render
picture 640 pixel wide, but normally, pages are served as-
suming a 320 pixel wide screen).

max_image_height any integer number Height of the images viewable (usable) width expressed

in pixels. This capability refers to the image when used in
“mobile mode” (see explanation for max_image_height)

physical_screen_width any integer number Screen width in millimiters

physical_screen_height any integer number Screen height in millimiters

dual_orientation true/false Some devices may be flipped, i.e. user may change orienta-

tion, effectively inverting screen_width and screen_height
for mobile web browsing and, possibly, for other functions.

authorization access rights of personnel, as well
as the internal hospital policy issues, are out of
scope of our contribution.
The entrance to our service is delegated via
a specific URL, common to all visitors (single
sign-on) whatever type of wireless device they
have. The web page that opens includes some
welcome information and a button that originates
a HTTP request (an HTTP GET message) for ac-
cessing the patients' record. Figure 3 illustrates
the welcome page.
Dynamic content adaptation according to the
WURFL paradigm is at first based on the devel-
opment of the CGI technology that reads the User
Agent header by the incoming HTTP requests. In
our implementation we have chosen Java Servlets
to this end. The extracted User Agent type is then
searched in the WURFL file to see if it matches
any of the WURFL entries. If yes, the associated
terminal capabilities are returned to the servlet,
so the requesting terminal is classified to one of
the capability classes we have considered for the
client devices. For each class an associated XSLT

file has been created. We have also specified a
XML schema with medical information represent-
ing the patient's record. Content adaptation is
achieved by applying the XSLT template that
corresponds to the capabilities class of the request-
ing terminal device over the XML file that contains
the patients' data. The resulting transformation is
an xHTML web page that the requesting terminal
device has the capability to present without any
distortion or other displaying problems.
For parsing the WURFL file and returning
specific values to the servlet engine, we have used
the WURFL parser provided at (WURFL parser),
properly adapted for our implementation.
The following sections elaborate further on
these procedures.

Terminal Devices' Classification

At first, we need to clarify the potential types
of devices that might be present in the hospital
environment, as these represent the means used
by the medical personnel to access the patients'