PHYSICAL DOCUMENT ADAPTATION TO USER’S CONTEXT
AND USER’S PROFILE
Hassan Naderi and Béatrice Rumpler
INSA LYON, Bâtiment Blaise Pascal, 7, Av. Jean Capelle F69621 Villeurbanne Cedex, France
Keywords: Mobile device, Document adaptation, Physical Document Adaptation (PDA), Context, User’s delivery
preferences.
Abstract: Modern technology promises mobile users Internet connectivity anytime, anywhere, and using any device.
However, given the constrained capabilities of mobile devices, the limited bandwidth of wireless networks
and the varying personal preferences, effective information access requires the development of new
computational patterns. The variety of mobile devices available today makes device-specific authoring of
web content an expensive approach. The problem is further compounded by the heterogeneous nature of the
supporting devices and the users' behaviour. This research investigates the challenges posed by these
problems, and proposes a context-aware adaptation framework to bridge the gap between the existing
Internet content and today's heterogeneous computing environments.
1 INTRODUCTION
The rapid advances in wireless communication
technologies with their integration into mobile
devices such as mobile phones, PDA, and portable
computers provide a technical infrastructure that
enables a broad range of mobile services and
applications. These devices are designed to help
people access and to manage information. While
they provide greater access to online information,
they also suffer from significant limitations such as
small screen-sizes, slow connection, and limited
input capabilities. A typical cell phone screen is 200
times smaller than a standard PC monitor. This
imposes limits on one's ability to locate and display
the right information quickly at the right time, and
therefore the information overload problem itself
becomes more serious. Because these access devices
are becoming more and more popular, there is a
need to make the next generation of information
retrieval systems capable of automatically adapt the
found document to the user's situation (cf. § 4,
Figure. 1).
In section 2, we study the actual approaches to
adapt a document to a given situation. In section 3
we present our proposition to adapt a given
document to the user's situation. In section 4 we
define the concept of user's situation. In section 5 we
show how the user's situation influences the process
of Physical Document Adaptation (PDA). In order to
simplify and clarify the process of PDA we have
categorized the documents' components in two main
classes: structural components and logical
components (section 5). In section 6 we propose a
formula to estimate the optimal size of the adapted
document which is based on the user's situation.
2 RELATED WORKS
Since now, there have been great efforts to provide a
unified web which is accessible from many types of
devices. Device independent access to information
has been identified as a fundamental principle of the
W3C Device Independent Working Group (Gimson
2003). Several approaches for providing adaptive
web content delivery over heterogeneous and
dynamic environments have been investigated.
Often in these approaches, markup languages play a
major role to provide an adapted content for
different contexts. Some of these approaches try to
extend existing languages and content models with
new elements and attributes (Lewiz 2002, Mandyam
2002). The other approaches try to define new
languages which are completely device independent
(Grassel 2002). Their objective is to build a new
92
Naderi H. and Rumpler B. (2007).
PHYSICAL DOCUMENT ADAPTATION TO USER’S CONTEXT AND USER’S PROFILE.
In Proceedings of the Ninth International Conference on Enterprise Information Systems - HCI, pages 92-97
DOI: 10.5220/0002384300920097
Copyright
c
SciTePress
markup language that can be used to create the new
generation of documents which can be displayed on
various devices in different contexts. These
approaches use a new tag set to highlight the most
pertinent parts of a document according to different
contexts. These approaches have some limitations:
1- They require some efforts from the author and
they are time-consuming. 2- They produce different
versions of a document for different contexts.
Therefore finding an appropriate version of a multi-
version document to a given context is a difficult
task because there is not an ideal method to match
the user's context to the author's defined document's
context. 3- The author has to produce the different
versions of a document for each context. As there
are a lot of contexts, it's unlikely to produce a
specific version of a document for each context. 4- It
may be feasible for the next generation of
documents but as we have mentioned there is a
serious need to adapt the actual documents (Kurz
2004).
We believe that the user's situation can be used
to roughly determine the characteristics of the
adapted document. In this paper, we propose a
mechanism to automatically adapt a given document
based on the user's situation. For example, if the
user's situation indicates that the user has a mobile
device unable to display the pictures, then the
system must eliminate the document's pictures
3 DOCUMENT ADAPTATION
Indeed, our adaptation system is based on two types
of adaptations: Physical Document Adaptation
(PDA) and Semantic Document Adaptation (SDA).
By separating the PDA from the SDA, it will be
easier to build a document suited to the user's
situation. In the two following paragraphs we will
briefly explain each of these adaptation types and
then the PDA will be elaborated in this paper.
SDA answers to this question: which textual
parts of a document must be selected to be displayed
on the user's device to semantically satisfy the user's
request? The SDA approaches are similar to the
document summarization methods. In this step, the
wasted information will be eliminated from the
original document, based on the user's situation and
his query in order to enrich the document's content.
PDA is the process of selection, modification or
elimination of the physical components of the
document (cf. §5) based on the user's situation.
Recognizing the size of the adapted document (the
total size of the selected components to create the
adapted document) plays an important role in a
successful adaptation. In other words, a competent
adaptation system must be able to estimate the size
of the adapted document according to the given
situation.
The size of an adapted document is a dynamic
value related to the user's situation. More the user's
situation is restricted more the size of adapted
document must be reduced. An adaptation system
which is not able to estimate the size of an adapted
document may generate a too long or too short
document. For example if the system sends a lot of
information to a mobile user who is time restricted,
he can’t efficiently find what he wants. Inversely, he
will not be satisfied when the system sends him
insufficient information.
In what follow we explain our methodology to
create the textual part of adapted document. The
steps are:
1- Extracting and sorting the pertinent phrases
based on the user's requirements.
2- Estimating the size of the textual part of the
adapted document based on the user's
situation.
3- Calculating the number of phrases (N) which
must be displayed on the user's device.
4- Selecting the N most pertinent phrases form
the sorted list of phases.
5- Displaying N selected phrases to user by
respecting their order in the original
document.
Knowing the number of phrases to display on the
user's device is essential to respect the order of the
phrases in the original document. We propose a
formula in section 6 to estimate the optimal size of
the adapted document.
So far it has been shown that the user situation
has an important role in document adaptation. In
what follows we describe our definition of user's
situation, which is essential in the PDA process as
well as for estimating the optimal size of an adapted
document.
4 USER'S SITUATION
In most of the proposed systems, the user's
preferences and the context's characteristics (such as
user's device) are grouped in the same category. In
such systems, if a user uses two different devices,
the system will associate him two different profiles.
This problem is because the context includes the
user's characteristics.
PHYSICAL DOCUMENT ADAPTATION TO USER’S CONTEXT AND USER’S PROFILE
93
Time Availabl
e
Time
Location
Device
NetworkSoftware
Context Profile
S
p
atial-tem
p
oral EnvironmeAccess Platfor
m
Histor
y
Securit
y
User Profile
Preferences of
deliver
y
Domain of
interest
Identification
User Situation
Figure 1: User's situation components.
In order to solve this problem in our system, we
propose to separate the user profile and the context
profile. Thus in our system both of them characterize
the user's situation (Figure 1). The parameters in
Figure 1 are represented by three different colours to
illustrate their different roles in the semantic or
physical adaptation processes. The white elements
are related to the SDA, the black elements are
related to the PDA, and the components that can be
used for SDA and PDA (i.e. user's personal data) are
shown by the grey-white elements. Thus according
to Figure 1, SDA is roughly based on the user profile
and PDA is based on both the context profile and the
user profile (Figure 2).
As PDA is affected by both user and context
profiles, sometimes some conflicts may appear
between the user's delivery preferences and the
user's context. For example, a user may want to see a
picture (preference) but his screen (context) is not
able to display it. So a decision engine has been
designed in our system to solve such conflicts
between the user’s context and the user's delivery
preferences (Lum 2002, Naderi 2006a).
Figure 2: PDA based on context and user's preferences.
As mentioned, adapting a document is based on
the user's situation. The more the user's situation is
restricted the more the original document must be
adapted. So characterizing the user's situation plays
an important role for adaptation systems. In what
follows we will explain the main parts of the user's
situation: the context profile and the user profile.
4.1 Context Profile
The context's components include the user's device,
the network, the user's available time, etc. (Figure
1). These components impose restrictions on the
process of PDA. For example a mobile device may
be unable to display a picture because of the
network's speed or because of the device's
capabilities. As it has been shown in Figure 1, the
only element from the context profile which is
related to SDA is Location. It means that this
element is a SDA related component and it has no
influence on PDA process.
In our proposition, we separate the contextual
information into three main categories:
Access platform: divided in three sub-categories:
- Device: represents the basic hardware features such
as screen size, memory capacity, etc.
- Network: such as the network’s price, bandwidth,
reliability, etc.
- Software: such as available browser, virtual
machine, etc.
Spatial-temporal: includes three parts:
- Available time: user's availability time.
- Time: represents the current time and date.
- Location: user’s absolute or relative address.
Environment: the conditions which can influence
the user’s behaviour (noise...).
In the section 5, we will explain how a document
can be physically adapted, based on the black
elements (Figure 1).
4.2 User Profile
The user profile is another component of the user's
situation, which plays an important role in the
process of the SDA. The main role of user profile is
to help the adaptation system to semantically adapt a
given document to the user's situation. Without a
user model, a system works exactly in the same way
with all users. But users are different: they have
different background, different knowledge about a
subject, different preferences, goals and interests.
Physical Document
Ada
p
tation
Context
User profile
User's delivery
Document
Adapted
document
ICEIS 2007 - International Conference on Enterprise Information Systems
94
The user's interactions will be registered in the user
profile in order to recognize his preferences and
domain of interest. As it has been shown in Figure 1
"user's delivery preferences" is the only black
element from the user profile which affects the
process of PDA. The user's preferences will be
recorded in this component to more properly display
a given document on his device. For example, a user
may indicate in his profile that he doesn't want to see
any pictures on his device, or he just wants to see the
title and a small summary of the document.
We have defined a typology of the user profile
based on five dimensions:
- Identification: includes the user's identity
information such as name, job, etc.
- Domain of interest: expresses the characteristics of
information that the user wishes to obtain. It affects
the process of SDA.
- Preferences of delivery: It covers the flexible
constraints for restitution of information to the user.
PDA depends on this part of the user profile.
- Security: includes all information about the
security and privacy such as login/password.
- History: manages the interactions between the user
and the system. It can be used to find pertinent
information to users (Naderi 2006b).
5 PHYSICAL DOCUMENT
ADAPTATION
In the previous section we have introduced two
profiles which define the user’s situation. Both of
them have an important role in the PDA process. In
this section we study the different possibilities for
the document adaptations to the user’s situation.
As we have mentioned before, PDA means
selecting, adapting and/or eliminating document's
components (or fragments) to satisfy user’s and
context’s restrictions. Defining the document
fragmentation is an important part of PDA. The
fragmentation is used to adapt the document to
different contexts. Once document fragmentation is
defined, the system can easily use the different
components according to the user's situation (context
+ user's preferences).
To simplify the PDA process, we have defined
two types of components: structural components and
logical components. According to these document’s
components, we have defined two types of PDA’s
respectively: structural document adaptation and
logical document adaptation. In what follows we
describe these two types of PDA.
5.1 Structural Document Adaptation
The structural components include the objects such
as: texts, figures, tables, diagrams, formulas, etc.
Different devices can display the different structural
components with different properties. For example a
device can display simple tables but it can’t display
complex pictures. By having the device’s
characteristics (in the context profile) such as the
screen size, screen resolution, number of colours etc;
the system can recognize the device's ability to
display a particular component. The aim of the
system, in the structural document adaptation, is to
select or modify the structural component. If the
adaptation is not possible the system will eliminate
the component before displaying the document.
The information concerning the ability of a
device to display a particular component can be
automatically extracted from the device’s
characteristics or it can be manually registered in the
device's profile by the user. By referring to the
device’s profile, the system determines whether a
component can be represented, or must be modified
or eliminated from a given document.
Beside the context’s role, to select, modify or
eliminate the structural components; the user himself
can specify his preferences to display the different
structural component. The user, by specifying his
preferences in his profile, enables the system to
select the appropriate components to construct an
appropriate adapted document. Therefore the system
will be able to automatically select, modify or
eliminate the structural components from the
original document by referring to the device’s
profile (a part of context’s profile) and the user’s
delivery preferences (a part of user’s profile).
5.2 Logical Document Adaptation
In this step, the structural document adaptation
subsystem sends a partially and structurally adapted
document to the logical document adaptation
subsystem. The logical components are the textual
parts of a document such as title, authors, abstract,
keywords, sections, subsections, conclusion,
references, document's summary, etc. The context
profile has no impact on the selection of the logical
components. Only the user can specify his
preferences about the representation of the logical
components. For example a user may only be
interested in reading the title and some keywords of
a document. Another user may be interested to have
an automatic summary of the document.
PHYSICAL DOCUMENT ADAPTATION TO USER’S CONTEXT AND USER’S PROFILE
95
Consequently the system can define the
appropriate document modifications by referring to
the user profile (structural and logical adaptation)
and the context profile (structural adaptation).
Therefore roughly all of the possible document's
modifications (structural, logical and semantic) can
be found in the user profile and in the context
profile. Thus by having enough information about
the situation, a document can be automatically
adapted to the user situation. The size and the
content of the generated document are the only
important elements which can't be directly
determined from the two mentioned profiles. In what
follows, we propose a formula to estimate the
optimal size of an adapted document, based on the
user situation.
6 SUMMARY’S SIZE
ESTIMATION
There have been some attempts to calculate the
optimal size of the document’s summary. Sweeny
(Sweeney 2003) has mentioned some static
percentage to generate an adapted document. For
example he suggests that a summary of 3% is the
most optimal value for the mobile phones (without
considering the size of the document!). But as
previously mentioned, the size of an adapted
document is not static and it must be dynamically
calculated, based on the user's situation. Although
the user can’t explicitly specify the size of the
needed information for the different situations,
however it can be calculated from the user's
preferences and the other contextual parameters. In
this section we try to list all of the parameters which
can influence the adapted document's size.
Subsequently, we propose a formula to show the
relationship between these parameters and the size
of the adapted document.
- Screen size N(ch): This is one of the most
important parameters for calculating the adapted
document’s size. The more the screen size is small,
the more the size of the delivered information must
decrease. The unit we choose to measure the screen
size is the number of characters which can be
displayed on the device’s screen. So it depends on
some of the user’s preferences such as the font's size
registered in the user profile.
- User’s availability time T
U
(s): The more the user is
time restricted the more the size of the adapted
document must decrease. The value of T
U
can be
explicitly supply by user, extracted from his agenda,
or it can implicitly be estimated based on the user’s
daily behaviours.
- Battery’s availability time T
B
(s): Contrary to the
desktop devices, the energy of a mobile device is
limited, so the system must consider the remaining
time of battery’s charge.
- Network network_effect: As mobile networks are
slower and more unreliable than wired networks, the
efficient time of connecting a mobile device to
network may be less than a desktop PC one.
- Speed of reading V(ch/s): the size of adapted
document depends on the speed of reading of user.
This speed can be calculated explicitly by testing the
user, or implicitly by observing the user’s behaviour.
- Input facility α: This factor represents the required
time to get a new page. When the screen size is
small the user needs more time to interact with
system to display the new page and the system also
needs some time to display the required page.
The above situational parameters limit the
efficient users time. By considering these parameters
the appropriate size of the adapted document (S) can
be calculated as follow:
(1)
In this formula t is the elapsed time because of
contextual restrictions such as the small screen size.
It's equal to the number of displayed page (S/N-1)
multiplied by the required time to change one page
(α
). According to the above formula, the more the
screen size (N) decreases, the more the number of
displayed pages (S/N) increases and therefore the
more the elapsed time increases. T is the efficient
user’s availability time that can be calculated form
the following formula:
(2)
The above formula permits to calculate the size
of a textual summary which simply can be used to
calculate the number of phrases which must be
displayed on the user's device. When the user is just
interested in the textual contents (or the original
document doesn't include the other physical
components such as picture) the above formula can
effectively work. But sometimes the users may be
interested in the other physical components. In this
case, the user requires some time M to read the
1_0
_)T,(TminT
BU
×=
effectnetworkwhere
effectnetwork
VαN
α)(TVN
α
N
V
1
)-T(V
S
])1
N
S
(-T[Vt)-(TV TV S
+
××
=
×+
×
=
××=×=
×=
α
α
ICEIS 2007 - International Conference on Enterprise Information Systems
96
physical components (i.e. pictures, tables, graphs
etc). So the formula (1) will be replaced by:
(3)
The calculation of the required time to read the
non textual physical components is out of the scope
of this paper and requires more efforts. The user can
explicitly specify the average value of M in his
profile.
Therefore by the above formulas our system will
be able to estimate the optimal size of the
information which must be displayed on the user’s
device.
7 CONCLUSION
We have proposed a methodology to create
documents adapted to the user's situation. The user's
situation in this paper includes two main profiles:
context profile and user profile. Physically
Document Adaptation (PDA) and Semantically
Document Adaptation have been defined and then
we have explained how the situational parameters
can be used to physically adapt a given document to
the user's requirement. We have divided the PDA
process into two sub-processes: structural document
adaptation and a logical document adaptation. We
have explained that knowing the size of an adapted
document plays an important role in an adaptation
system. So we have proposed a new formula which
is able to estimate the size of the adapted document,
based on the user’s situation.
ACKNOWLEDGEMENTS
This research is partially supported by the French
Ministry of Research and New Technologies under
the ACI program devoted to Data Masses (ACI-
MD), project #MD-33.
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αVN
α)-M-(TNV
t)-M-(TV TV S
×+
×
=×=
×=
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97