Abstract
This document describes the Device Description Repository Core Vocabulary for Content
Adaptation in the Mobile Web, described in the charter of the Device Descriptions
Working Group, as well as the process by which the Vocabulary was defined.
1 Introduction
This document identifies properties that are considered essential for adaptation of
content in the Mobile Web. Its intended use is to define a baseline Vocabulary for
Device Description Repository (DDR) implementations.
The Vocabulary defined in this document is not intended to represent an exhaustive
set of properties for content adaptation. DDR Implementations that require
additional properties are free to make use of additional vocabularies. The process
of creating a new Vocabulary can be modeled on the process described in this
document. Implementors are encouraged to make use of the UWA ontology [UWA-Ontology] to suggest
extensions to it.
Implementers of DDR solutions that are intended to support content adaptation for
Mobile Web-enabled devices should, at a minimum, support the DDR Core Vocabulary as
defined in this document.
This document is maintained by the MWI DDWG and arrangements will be made to assign a
maintainer after the closure of the DDWG.
2 Process
The DDWG established a lightweight process for accepting and evaluating contributions
to the DDR Core Vocabulary, comprising the following:
2.1 Questionnaire
A public questionnaire was
launched to request proposals for inclusion in the Core Vocabulary, with the
following data being obtained for each proposal:
Description: A brief description of the proposed
Property.
Type: The data type associated with the Property.
Justification: An argument put forward to justify the
Property being part of the Core Vocabulary. This should explain why the
proposed Property is essential for basic adaptation of typical Web
content, in the context of Mobile Web-enabled devices.
Measurement: A explanation of how this Property is
evaluated, suggesting where appropriate the units of measurement.
2.2 Assessment
Proposals submitted via the questionnaire were assessed to determine if they were
appropriate for the Core Vocabulary. The following guidance was used to
determine the main candidates:
The Property must be considered essential to achieve adaptation of Web
content for mobile devices.
The Property must be objective, unambiguous and any measurements must be
reliably repeatable.
The Property should not be derivable from other essential Properties.
There should be a reasonable expectation of acquiring values for the
Property (e.g. from manufacturers).
The group voted on each proposed Property. Those Properties that were rejected
were further assessed for the possibility of being useful in other domains, and
where identified, external groups were informed of these Properties so that they
may consider developing their own vocabularies.
3 Vocabulary, Property and Aspect
The DDWG's work on modelling the Delivery Context has highlighted the
desirability of identifying components of actual Delivery Contexts and
classifying their types.
Components of the Delivery Context are, typically, a
device, a user agent, a network connection, and possibly one or more proxies. The
notion of "Aspect" captures the type of such components, and allows Properties
of vocabularies to refer to specific Aspects of the Delivery Context, or to the
Delivery Context as a whole.
The terms "Vocabulary", "Property" and "Aspect" are defined in [DDR-Simple-API], under Section 3. Vocabularies.
3.1 Aspects of the Core Vocabulary
This Vocabulary defines two Aspects, webBrowser and device,
which serve to disambiguate the usage of Properties such as Vendor.
Other Vocabularies may define other values for Aspects.
3.1.1 device
An apparatus through which a user can perceive and interact with the Web (see Device in [DIGLOSS])
3.2 Property Names and Property Value Types
Refer to [DDR-Simple-API] Section 3. Vocabularies for allowable identifier syntax, for allowable value data types and how to represent enumerations in vocabularies that are to be used with the DDR Simple API.
The Property identifiers in this Vocabulary are associated with the namespace
http://www.w3.org/2008/01/ddr-core-vocabulary. This
namespace will change if the Core Vocabulary is updated.
The enumerations described in this document contain initial values that should be
supported by all implementations of the Core Vocabulary and which may be
supplemented by further DDR specific values.
4 Properties
This is a list of the Properties in the DDR Core Vocabulary.
The Default Aspect for the Properties of the Core Vocabulary is device where a Property applies to more than one Aspect.
4.1 Vendor
4.1.2 Associated Aspects
webBrowser, device
4.1.3 Description
The name of the maker (OEM) of a device, browser or some other component
(e.g. Mozilla).
4.1.6 Note
While knowing the Vendor, Model and Version of a device is not essential
when carrying out content adaptation, it is very important when designing an
application, building reports and analytics, and analyzing logs and usage
data.
4.2 Model
4.2.2 Associated Aspects
webBrowser, device
4.2.3 Description
The model name of a device, browser or some other component (e.g.
Firefox).
4.2.6 Note
See Vendor above.
4.3 Version
4.3.2 Associated Aspects
webBrowser, device
4.3.3 Description
The version number of a component (e.g. 2.0.0.10)
4.3.6 Note
See Vendor above.
4.4 Display Width
4.4.2 Associated Aspects
webBrowser, device
4.4.3 Description
The total number of addressable pixels in the horizontal direction of a
rectangular display when held in its default orientation. The Property does
not apply to displays that are not rectangular or square.
4.4.4 Measurement
The pixels are counted from the top left corner to the top right corner, and
the result expressed as an integer.
4.4.7 Note
Needed to fit/crop images, text or other width-adaptable content to the
screen. Especially useful for LTR and RTL content, where vertical scrolling
would be the norm but horizontal scrolling is not desirable. Identified as
an important Property by the DDWG in its Top N finding [TopN]. Present in UAProf [UAPROF].
Present (and used) in existing adaptation solutions.
4.5 Display Height
4.5.2 Associated Aspects
webBrowser, device
4.5.3 Description
The total number of addressable pixels in the vertical direction of a
rectangular display when held in its default orientation. The Property does
not apply to displays that are not rectangular or square.
4.5.4 Measurement
The pixels are counted from the top left corner to the bottom left corner,
and the result expressed as an integer.
4.5.7 Note
Needed to fit/crop images, text or other width-adaptable content to the
screen. Especially useful for LTR and RTL content, where vertical scrolling
would be the norm but horizontal scrolling is not desirable. Identified as
an important Property by the DDWG in its Top N finding. Present in UAProf.
Present (and used) in existing adaptation solutions.
4.6 Display Color Depth
4.6.1 ID
displayColorDepth
4.6.2 Associated Aspects
device
4.6.3 Description
The color depth of a display.
4.6.4 Measurement
Count the number of bits used for color definition.
4.6.6 Note
If you are making any image or video transcoding it is important to know the
maximum colors addressable by the screen. Measuring in bits should make it
easier for programmatic conversions.
4.7 Input Devices
4.7.2 Associated Aspects
device
4.7.3 Description
This Property described which input devices are available to the user.
Normally most mobile devices such as mobile phones will have a keypad, it is
common, though, to have a rocker, a stylus and a touch screen in PDAs,
tablets and so on.
4.7.4 Measurement
Observation of features or study of specifications.
4.7.5 Type
Enumeration of values as follows (or other values supported by individual
DDRs:
| Value | Description | Reference |
|---|
| keypad | classic 12 button mobile phone keypad | |
| touchScreen | touch screen that allows pointing to an area on the screen | |
| stylus | a stylus normally works in combination with a touch screen, the
stylus provides higher precision | |
| trackball | a little sphere that acts like a trackball mouse | |
| clickWheel | a wheel that is normally placed either below the screen or on
the side of the device that lets the user quickly move up and
down and click on link or items on the screen | |
4.7.6 Note
From an application perspective knowing that a device features a stylus or a
touch screen can open many possibilities to greatly enhance the user
interaction.
4.8 Markup Support
4.8.2 Associated Aspects
webBrowser
4.8.3 Description
Set of mark-up languages a client supports.
4.8.4 Measurement
Claim of conformance by the vendor.
4.8.5 Type
Enumeration with values chosen from the following (or other values supported
by individual DDRs):
4.8.6 Note
In order to provide the appropriate mark-up when serving a web page, it is
required that the server knows the supported mark-ups. Accept headers are
often not accurate enough and can be modified by proxies in-between.
4.9 Stylesheet Support
4.9.1 ID
stylesheetSupport
4.9.2 Associated Aspects
webBrowser
4.9.3 Description
Set of Style Sheet languages a client supports.
4.9.4 Measurement
Claim of conformance by the vendor.
4.9.5 Type
Enumeration with values chosen from the following (or other values supported
by individual DDRs):
| Value | Description | Reference |
|---|
| css10 | CSS Level 1 |
[CSS10]
|
| css21 | CSS Level 2 Revision 1 |
[CSS21]
|
| wcss10 | WCSS |
[WCSS]
|
4.9.6 Note
Style sheets are needed to define how the page should be laid out, positions
and colors.
4.10 Image Format Support
4.10.1 ID
imageFormatSupport
4.10.2 Associated Aspects
webBrowser
4.10.3 Description
Set of image formats a client supports as part of a Web page (as distinct from formats that may be downloaded).
4.10.4 Measurement
Claim of conformance by the vendor.
4.10.5 Type
Enumeration with values chosen from the following (or other values supported
by individual DDRs):
4.10.6 Note
Images are the first step to make content more compelling. Accept headers
are often not accurate enough to determine which formats are supported and
can be modified by proxies in-between.
4.11 Input Mode Support
4.11.1 ID
inputModeSupport
4.11.2 Associated Aspects
webBrowser
4.11.3 Description
The preferred ways of supporting specific formats for input type="text"
fields. This can be done with the 'format' attribute, as a WCSS property or
using the 'inputmode' attribute.
4.11.4 Measurement
Test using controls specifying the format
with the mechanisms cited.
4.11.5 Type
Enumeration with values chosen from the following (or other values supported
by individual DDRs):
| Value | Description | Reference |
|---|
| useFormatAttribute | Use the format attribute of the input
element - an extension to XHTML-MP. |
[OpenWave-Format-Attribute]
|
| useWCSS | Use the WCSS -wap-input-format property. |
[WCSS]
|
| useInputmodeAttribute | Use the inputmode attribute. |
[XHTMLBasic11]
|
4.11.6 Note
Assists user with input by setting the device input mode appropriately.
4.12 Cookie Support
4.12.2 Associated Aspects
webBrowser
4.12.3 Description
The ability of a client to store cookies and send them when appropriate.
4.12.4 Measurement
A web server sets a cookie in an HTTP Response. The Mobile Web browser makes
a subsequent HTTP request. If the browser supports cookies the HTTP request
should contain the cookie previously set by the web server.
4.12.6 Note
It is very important to know if a browser support cookies, among other
things, to support the concept of user session. An adaptation solution that
knows that a device does not support cookies can fall back to a URI
rewriting mechanism.
4.13 Script Support
4.13.2 Associated Aspects
webBrowser
4.13.3 Description
Set of scripting languages supported.
4.13.4 Measurement
Manufacturer claim of support of a scripting language or dialect.
4.13.5 Type
Enumeration with values chosen from the following list (or other values
supported by individual DDRs):
| Value | Description | Reference |
|---|
| ecmascript-MP | Supports ECMAScript Mobile Profile |
[ECMAScript-MP]
|