=Paper=
{{Paper
|id=Vol-485/paper-2
|storemode=property
|title=Handling Users Local Contexts in Web 2.0
|pdfUrl=https://ceur-ws.org/Vol-485/paper2-F.pdf
|volume=Vol-485
|dblpUrl=https://dblp.org/rec/conf/um/Al-JabariMT09a
}}
==Handling Users Local Contexts in Web 2.0==
https://ceur-ws.org/Vol-485/paper2-F.pdf
Workshop on Adaptation and Personalization for Web 2.0, UMAP'09, June 22-26, 2009
Handling Users Local Contexts in Web 2.0: Use
Cases and Challenges
Mohanad Al-Jabari1? , Michael Mrissa2 , and Philippe Thiran1
1
PReCISE Research Center, University of Namur, Belgium
2
SOC Research Team, LIRIS, University of Lyon 1, France
Abstract. Creating, updating, and aggregating Web contents from dif-
ferent Web users and sites form the heart idea of Web 2.0. However, Web
users originate from different communities, and follow their own seman-
tics (referred to as local contexts in this paper) to represent and interpret
Web contents. Therefore, several discrepancies could rise up between the
semantics of Web authors and readers. In this paper, we present several
Web 2.0 use cases, and illustrate the possible challenges and trends to
handle the local contexts of Web users in these use cases.
1 Introduction
During the last years, the emergence of the Web 2.0 has revolutionized the
way information is designed and accessed over the internet. The term Web 2.0
was officially coined by Tim O’Reilly in [11] as a set of design principles and
exemplified by sites such as Wikipedia3 , MySpace4 , Upcoming5 , etc. However,
several researchers including Tim O’Reilly himself argue that there is no clear-
cut definition of this term [6, 2, 3].
The heart idea of Web 2.0, in addition of using Web technologies as a plat-
form, lies into the sharing of Web contents from different sources. Community
collaborations and contents mashups are the most common Web 2.0 features [3].
To illustrate these features, let us distinguish them from the classical Web (called
“Web 1.0”) features as follows:
– Community collaboration. In Web 1.0, a few Web authors create and
update Web contents for relatively passive Web readers. However, Web 2.0
sites enable Web users not only to browse the Web but also to create, update,
and share Web contents in usually self-organizing manner. Hence, Web users
now can act as active Web authors.
– Contents mashups. In Web 1.0, Web contents (information and services)
on a single web page are usually belong to one Web site. In Web 2.0, contents
from several sites can be aggregated, mixed, and displayed together.
?
Supported in part by the Programme for Palestinian European Academic Coopera-
tion in Education (PEACE).
3
http://wikipedia.org
4
http://www.myspace.com
5
http://upcoming.yahoo.com
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Workshop on Adaptation and Personalization for Web 2.0, UMAP'09, June 22-26, 2009
The emerging results of community collaboration and contents mashups could
not be achieved by individual users and individual Web sites, respectively. Each
user gains more from the systems than he puts into it. Also, one Web site can
not satisfy all the users’ needs. Contents from different sites are to be aggregated
and mixed together to satisfy complex users’ requests.
1.1 Users Local Contexts
The Web gathers billions of Web users from all over the world. These users orig-
inate from different communities, and follow their local contexts for interacting
with Web contents. By local context, we means a set of common knowledge such
as a common language and common cultural conventions such as measure units,
keyboard configurations, character sets, notational standards of writing times,
dates, numbers, currency [14, 5].
Since different communities usually have different local contexts, a same con-
cept (a Web concept) could be represented differently by different Web authors.
Also, the same Web content (the representation of a Web concept) could be
interpreted in different ways by different Web readers. Hence, several discrep-
ancies could be arisen between the semantics of Web authors and readers. For
example, assume a French reader who wants to interpret a price Web content
which is authored by a British author. In this context, the price is represented
in British Pound and follows the British currency format (e.g., 1,234.50). As the
French currency is Euro and different format is used (e.g., 1 234,50), the price
must be converted from British Pound to French Euro by the reader. Note that
the situation can be even worse if the reader wants to interpret a date content.
The reader could misinterpret the date content (e.g., 07/08/2008) as the 7th
of August 2008 (following the French format) instead of the 8th of July 2008
(following the British format). Similar situations may occur with other pieces of
Web contents that are related to users’ local contexts.
1.2 Web 2.0 and Users Local Contexts
The emergence of the Web 2.0 raises new challenges. Web contents in a single
page can be authored (created and updated) by several authors who have differ-
ent local contexts. Moreover, contents authored from several authors on several
Web sites could be dynamically aggregated, mixed, and displayed together in
a single Web page. This paper presents several possible Web 2.0 use cases and
explores some possible challenges and trends for handling users’ local contexts
in these use cases.
This paper is organized as follows. Section 2 presents several Web 2.0 use
cases. Section 3 introduces a set of concepts that could be represented and in-
terpreted according to users’ local contexts and the challenges of handling them
in the Web 2.0 use cases. Section 4 introduces semantic annotation as a possible
solution. Finally, Section 5 concludes the paper.
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Workshop on Adaptation and Personalization for Web 2.0, UMAP'09, June 22-26, 2009
2 Web 2.0 Use Cases
In this section, we describe several possible use cases that users could perform
when they use Web 2.0 systems. By no means we aim at covering all Web
2.0 use cases, but we attempt to classify the aforementioned Web 2.0 features
(i.e., community collaboration and contents mashups) into three use cases: Web
contents creation, Web contents update, and Web contents aggregation.
2.1 Web Contents Creation
Several Web 2.0 systems enable Web authors to create Web contents, without
giving the opportunities to update the published contents or parts of them. We
focus on the Web contents creation in this use case. To illustrate this, let us
consider the following Web 2.0 services:
– Weblog (also called blog). Web 2.0 systems such as WordPress6 allow a single
author to create Web contents (e.g., scientific articles,privacy issues, etc.)
called post, whereas other secondary users can add comments to contents
created by the original author as new html nodes.
– Bulletins Section. Web 2.0 social systems such as Facebook 7 and M ySpace
provide a service to a group of users called “bulletin board”. Bulletin board
allows a user to add a piece of Web content (e.g., text message), whereas other
users on the group list can see this content. Bulletins can be useful to contact
an entire friends list without resorting to messaging users individually.
– Group Section. Social systems also provide a service called “group section”.
One or more users can create a common page (i.e., group section). The group
creator(s) can invite any one to join, deny user’s join request, delete or update
users’ contents, etc. Joined users, in addition to the group creator(s), usually
can browse and create contents on the group section.
2.2 Web Contents Update
Several Web 2.0 systems enable Web authors to update Web contents after
publishing. In this use case, a Web author could update the Web contents that
she/he creates (referred to as a personal contents update) or the Web contents
that other Web authors create (referred to as a community contents update).
The following Web 2.0 services illustrate this use case:
– Personal contents update. Web 2.0 commerce systems such as eBay8 allow
a Web user to update the contents about the items she/he wants to sell.
A user can update the contents concerning these items like the price, the
photos, the selling location, etc. Other users can not change these pieces of
contents. In addition, social systems allow a user to update his own profile
such as login name and password, preferred language, interests, etc.
6
http://wordpress.org/
7
http://www.facebook.com/
8
Available on http://www.ebay.com/.
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Workshop on Adaptation and Personalization for Web 2.0, UMAP'09, June 22-26, 2009
– Community contents update. Wiki systems such as Wekipedia allow one or
more users (usually authorized users) to create Web contents as a set of in-
terlinked Web pages and update these contents using creating and editing
services. For example, a Web user can define the term local context or update
the existing definition authored from other author(s). In addition, collabo-
rative editing systems such as Google Docs allow a group of users (might
be from different locations) to collaboratively create and update documents
(e.g., word document) online. Finally, the group creator(s) of the group sec-
tion presented above can update the contents created by joined users.
2.3 Web Contents Aggregation
Several Web 2.0 systems and technologies provide Web contents aggregation
and mixing services. In this sense, the aggregation and mixing services could be
performed on client-side (referred to as a client-side aggregation) or on a specific
server-side application (referred to as a server-side aggregation). The following
Web 2.0 services illustrate this use case:
– Client-side aggregation. RSS feed reader (aggregator) is the most known
technology that allows client-side applications (e.g., Web browser) to find
out and collect Web contents from RSS-enabled Web sites9 . In addition,
Piggy bank [7] and Kalpana [4] provide client-side aggregation services. These
services aim at enabling Web readers to extract and aggregate personal infor-
mation from different Web sites, and to store them locally in RDF formats.
– Server-side aggregation. Several Web 2.0 systems mix Web contents from
different sites. For example, Google provides an advertisement service called
adSense10 which enables Web site to add text, image, or video advertisement
from other Web sites. In addition, several Web 2.0 systems provide aggrega-
tion services for specific types of Web contents. For example, Technorati 11
aggregates and indexes different types of contents such Weblogs, photos,
news, DVDs, etc. Also, Technorati allows readers to search these contents
in different ways (e.g., readers can search Weblogs according to Weblogs’
langauge).Upcomming is another system that aggregates events from users
communities and commercial sites. Users can indicates their plans by mark-
ing that they are “going” to or “interested” in events that are occurred in a
location, date, future periods, etc. Also, users can choose which events who
are interested in such as education, music, sports, etc.
Finally, several E-commerce systems compose Web services together (e.g.,
airplane ticket reservation, car rental reservation, and hotel reservation) from
different service providers (i.e., Web sites) to satisfy a complex user request.
In this sense, we can assume these systems as server-side aggregators.
9
Any website that offers RSS feeds for its content.
10
http://www.google.com/adsense
11
http://technorati.com/
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Workshop on Adaptation and Personalization for Web 2.0, UMAP'09, June 22-26, 2009
3 Web 2.0 Use Cases and Users Local Contexts
As we mentioned, several discrepancies could be arisen between the semantics
of Web authors and readers, since they could have different local contexts. In
this section, we initially presents a set of concepts that could be represented and
interpreted according to users’ local contexts. Then, we discuss the challenges of
handling the local contexts of these concepts in the above Web 2.0 use cases.
3.1 Context-Sensitive Web Concepts
Based on local context, we aim at classifying Web concepts into context12 -
sensitive and non-context-sensitive concepts. Context-sensitive concepts refer to
the concepts which could be represented in different ways by different authors.
The following list identifies a set of context-sensitive concepts. By no means we
claim that this list covers all context-sensitive concepts, but we try to address
the main concerns that are rose up in the aforementioned use cases [10, 9].
– Date/time. Date refers to a particular day of a month or a year within
a calendar system (e.g., Gregorian, Islamic, Japanese, etc.). In addition,
different communities represent Date in different ways. The day, month,
and year are ordered differently, and different separators are used. Also, text
representation of Date depends on user’s local language and country. Finally,
Time could be represented in 12-hour AM/PM or 24-hour style, and with
different time zone.
– Number. In mathematics, Numbers are mainly used for counting and mea-
suring amounts or quantities of objects based on a number system. Different
local symbols are used to represent numbers (also called numerals such as
English and arabic numerals13 ). Also, different decimal and thousands sep-
arators (i.e., dot and comma) are used in different countries.
– Price. Price refers to a numerical monetary value assigned to a good, service
or asset. Prices are expressed in different formats, currencies14 , and Tax
systems (Tax rates, included/excluded, etc.).
– Physical quantities. Physical quantities such as weight, length, tempera-
ture, etc. are measured using a set of units called measure units. Countries
are used different measure systems (mainly Imperial and Metric systems),
different unit prefixes, and different error percentage15 .
– Telephone number refers to a unique sequence of numbers used to identify
a telephone endpoint. Based on ITU16 numbering plan E.164, each country
has a different international call prefix and country calling code. Further-
more, each country uses a specific telephone number’s format.
12
Context here refers to the local context.
13
See numeral systems on http://en.wikipedia.org/wiki/Numeral system
14
See ISO 4217 for used currency list.
15
More information available on http://en.wikipedia.org/wiki/Units of measure
16
International Telecommunication Union: http://www.itu.int/
15
Workshop on Adaptation and Personalization for Web 2.0, UMAP'09, June 22-26, 2009
3.2 Challenges of Handling Users Local Contexts
We can conclude that the local context represents a part of the semantic for
the above Web concepts. Also, the semantic discrepancies that could arise do
not relate to these concepts themselves, but rather to the local contexts of Web
authors and readers that are implicity used when they represent and interpret
these concepts.
In order to address this issue, several approaches have been proposed to
adapt Web contents to be suitable to readers’ local contexts [12, 14, 8]. These
approaches are mostly based on two assumptions: (1) the semantics of target Web
contents to be adapted are known in advance; (2) Web contents are represented
according to a single local context.
However, the use cases presented above illustrate that these assumptions are
not valid anymore. Web contents are shared (created, updated, and aggregated)
from different sources (i.e., Web users and Web sites). Hence, they are repre-
sented according to different local contexts and have heterogenous semantics.
Therefore, the following challenging issues should be tackled:
1. Semantic identification. What is the information that required to identify
the semantics of Web contents and the local contexts of Web users?
2. Semantic information management. How can the contents’ semantics and
the users’ local contexts information be managed in terms of acquiring, rep-
resenting, and storing this information? Also, what is the local context that
used for representing each piece of Web content?
Semantic Identification
As mentioned before, Web contents could be created, updated, and aggregated
from different sources. In this sense, different Web contents from different sources
could refer to the same context-sensitive concept. For example, different authors
could use cost, price, and amount contents to refer to the price concept. In
addition, the value of the price concept could be represented in different ways,
according to the authors’ contexts.
Moreover, Web contents can be stored, aggregated and hosted on the server-
side and can be aggregated and presented on the client-side. Server-side and
client-side applications can not interpret Web contents if they are represented
only using XHTML. Hence, a server-side application can not be aware if Web
contents such as cost, price, and amount refer to the price concept or not, and
it can not know which local context was used for representing them.
In this sense, several questions could be raised here. Firstly, what is the
information that required to identify the semantics of Web contents, so that
server-side and/or client-side applications can interpret that Web contents from
different sources refer to one context-sensitive concept? Secondly, what is the
(minimum) information required to identify the users’ (authors and readers)
local contexts, so that server-side and/or client-side applications can adapt Web
contents from authors’ contexts to readers’ contexts. One could argue that the
local context depends on users’ countries, which can be obtained from the IP
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Workshop on Adaptation and Personalization for Web 2.0, UMAP'09, June 22-26, 2009
address contained in the HTTP header. However, this assumption is not valid
as one country can have several communities (e.g., Belgium). Another question:
how can we identify the local contexts of cross-sites aggregated contents?
Semantic Information Management
In addition to the aforementioned issues, the information required to identify
the semantics of Web contents and the local contexts of Web users needs to be
acquired, represented, and stored.
In this sense, several questions have to been tackled. Firstly, how can the
required information be acquired from different sources (i.e., users and sites).
Assume the Web contents creation and update use cases. Does the required in-
formation be acquired directly from the authors or be acquired (predicted) from
the server-side applications? Also, when the required information be acquired?
(i.e., before contents creation or update, during contents creation or update).
Assume the Web contents aggregation use case. How can this information be
acquired from different sites.
Secondly, how should the required information be represented and where it
should be stored (i.e., on the server-side or on the client-side), so that the local
contexts of context-sensitive concepts can be handled in the above use cases.
For example, the required information should be accessible from the client-side
applications in order to handle the client-side aggregated contents. Also, it should
be accessible from the server-side applications in order to handle the server-side
aggregated contents.
Finally, how to specify the local context that used for representing each piece
of Web content? Assume the community update use case where one Web author
can update the contents created by other authors (e.g., Wiki contents). The
question here: are the updated contents related to the context of the original
author or the context(s) of the author(s) who update these contents? Moreover,
assume, in contents aggregation use case, the case where the authors’ local con-
texts for parts of the aggregated contents are not specified. How can this case
be handled?
4 Possible Solution
One possible solution to handle the aforementioned challenges is to directly rely
on the authors for annotating Web contents with semantic metadata, so that
the former become machine interpretable [15]. Semantic metadata are used to
describe contents’ semantics and users’ local contexts explicitly. In this sense,
Client-side and server-side applications can interpret a Web content (e.g., cost)
that is related to a specific context-sensitive concept (e.g., price). Also, they can
interpret that this content is represented according to a specific local context.
Therefore, Web contents can be adapted from authors’ local contexts to different
readers’ local contexts.
In addition, semantic metadata are accessible from server-side and client-side
applications, as they are combined with Web contents. In the content aggrega-
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Workshop on Adaptation and Personalization for Web 2.0, UMAP'09, June 22-26, 2009
tion use case, Server-side and/or client-side applications aggregate Web contents
together with the corresponding semantic metadata. Finally, the Web authors,
in contents update use case, should update Web contents and also the corre-
sponding semantic metadata.
In this field, there are two alternative approaches. The first approach aims
at standardizing the representation of Web contents and their semantics for
all sources. For example, representing the Date/Time concepts according to the
ISO 8601 specification17 . The second approach aims at allowing authors to repre-
sent Web contents in different ways, but explicitly annotate them with semantic
metadata (i.e., contents’ semantics and authors’ local contexts). Microformats
technology18 follows the first approach and RDFa19 technology follows the sec-
ond one [13, 10].
4.1 Microformats
Microformats propose a set of standards, or specifications, and reuse XHTML
attributes such as id and class to embed those specifications into XHTML doc-
uments. For example, the hCard specification identifies vocabularies based on
the vCard20 specification that provide semantic information about people and
organization. Microformats specifications standardize the representation of Web
contents and their semantics at different three levels as follows:
– Schema level. Identifying a specific schema for each Microformats specifica-
tion in terms of concepts and sub-concepts (called classes and subclasses)
that can appear and their cardinalities (e.g., required, optional, etc.), the
ordering of schema classes, etc. For example, hCard should have vcard class,
f n and n subclasses at minimum.
– Concept level. Identifying a specific semantic vocabulary (Semantic label)
for every class and subclass in each Microformats specification. Therefore,
standardizing contents’ semantics.
– Representation level. Identifying a specific representation for each class’s and
subclass’s values. The authors should follow these representations as much
as possible, so that Microformats parsers can interpret these representations.
Therefore, standardizing authors’ local contexts.
Server-side and/or client-side applications can interpret Web contents anno-
tated with Microformats (i.e., exchange, aggregate, adapt, etc.) without signifi-
cant loss of meanings. However, Microformats are not extensible and do not ful-
fill all authors’ use cases. In our previous work, we conclude that Microformats
remain rather limited as they propose a finite set of specifications [10]. Tech-
nically, Web authors can create new specifications, but it is not recommended
without extensive discussion with the Microformats community for a general (i.e.
17
http://en.wikipedia.org/wiki/ISO 8601
18
More information available on http://microformats.org/
19
More information available on RDFa wiki: http://rdfa.info/wiki/RDFa.
20
More information available on http://www.isi.edu/in-notes/rfc2426.txt
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Workshop on Adaptation and Personalization for Web 2.0, UMAP'09, June 22-26, 2009
worldwide) adoption. Until this point is reached, Microformats parsers could not
interpret what are considered as “exotic” Microformats specifications.
4.2 RDFa
RDFa provides a more abstract solution that aims at expressing RDF statements
in XHTML documents. More precisely, RDFa provides a collection of XHTML
attributes (reuses existing attributes such as content and rel and introduces new
ones such as about and property) to embed RDF statements in XHTML, whereas
it provides processing rules for extracting RDF statements from XHTML.
Web authors can reuse existing RDF-based semantic metadata (e.g., Dublin
Core and FOAF metadata) and create their own semantic metadata. Therefore,
RDFa is fully extensible. However, since Web contents and semantic metadata
from different sources are represented in different ways; the interpretation of
these contents (i.e., exchange, aggregation, adaptation, etc.) require a prior se-
mantic reconciliation between server-side and client-side applications [3].
In [1], we propose an approach that uses RDFa to annotate context-sensitive
concepts with authors’ local contexts, so that these concepts can be adapted into
different readers’ local contexts.
5 Conclusion
The main strength of the Web lies in its capacity to interconnect billions of
users from all around the world. However, this gathering of communities can
lead to the misunderstanding of Web contents as each community of users uses
its own context for interacting with Web contents. In this paper, we identified
new challenges in improving the context interpretation of Web contents in some
typical Web 2.0 use cases. We also explained how existing technologies such as
RDFa and Microformats can help people to better understand each other on the
Web. Based on [1], our future work aims at providing an intuitive way for helping
authors to annotate context-sensitive concepts with contextual attributes.
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