=Paper=
{{Paper
|id=Vol-2786/Paper7
|storemode=property
|title=Semantic Web End-User Tasks
|pdfUrl=https://ceur-ws.org/Vol-2786/Paper7.pdf
|volume=Vol-2786
|authors=Roberto García
|dblpUrl=https://dblp.org/rec/conf/isic2/Garcia21
}}
==Semantic Web End-User Tasks==
https://ceur-ws.org/Vol-2786/Paper7.pdf
47
Semantic Web End-User Tasks
Roberto Garcíaa
a
Universitat de Lleida, Jaume II 69, E-25001 Lleida, Spain
Abstract
In order to make the Semantic Web reach “real world” end-users it is important to consider
Semantic Web usability. User-Centered Design from the Human-Computer Interaction com-
munity might help in this respect. First of all, the user must be defined, together with the context.
Then it is possible to study user tasks. We focus our study of Semantic Web user tasks in end-
users and Semantic Web online applications, trying to contribute to establishing some UCD
guidelines that help the adoption of Semantic Web applications. However, we consider existing
analysis for Web systems and even online information systems in general in order to avoid
constraining our view to the current state of development of the Se-mantic Web. The proposed
set of end-user Semantic Web tasks is Search, Browse, Annotate, Mashup, Map, Share,
Communicate and Transact. They are used in order to study an existing Semantic Web platform
and an application based on it. This allows putting the tasks into practice and relates them to
some interaction patterns. Future work continues in this line, trying to connect the identified
patterns with existing and new interaction pat-terns in order to contribute additional guidelines
for UCD Semantic Web applications development.
Keywords 1
Semantic Web, Human-Computer Interaction, User Task, User Experience, User Interface
1. Introduction process, and the objective is to get usable and
accessible products.
In the context of HCI, User-Centred Design
The Semantic Web has been around for
(UCD) proposes facing the development
some time and many people are asking why it
process of interactive systems focusing on the
has not taken off as quickly as the World Wide
user and considering the Quality in Use,
Web did [1]. One of the main impediments is
standardised in ISO/IEC 25010:2011 [4]. The
that it is not reaching the end-users, who can
proposed development process starts with a
give it the required critical mass for widespread
characterisation of the target users and the tasks
adoption. End-users find Semantic Web
they carry out with the interactive system in
applications very hard to use, it is difficult even
order to meet their needs, and the metrics it
for researchers and practitioners working in the
proposes to evaluate the quality in use have
Semantic Web field [2].
been extended to Semantic Web exploration
Once Semantic Web technologies seem to
tools [5].
be quite mature, in order to facilitate its
The tasks supported by the early Web are
adoption, it is time to focus on the face
now neatly defined and are becoming part of
Semantic Web applications show to users [3].
Web developers’ common practice, making it
Human-Computer Interaction (HCI) is a
relatively easy to develop tools adapted to these
multidisciplinary effort to improve the human-
tasks following a UCD approach. Knowledge
computer interface. The focus is placed on the
about tasks in the Semantic Web is much less
user, i.e. to consider user needs from the
clear due to its novelty, but it is necessary in
beginning and through all the development
International Semantic Intelligence Conference, February 25–27,
2021, New Delhi, India
EMAIL: roberto.garcia@udl.cat
ORCID: 0000-0003-2207-9605
© 2021 Copyright for this paper by its authors. Use permitted under Creative
Commons License Attribution 4.0 International (CC BY 4.0).
CEUR
Wor
Pr
ks
hop
oceedi
ngs
ht
I
tp:
//
ceur
-
SSN1613-
ws
.or
0073
g
CEUR Workshop Proceedings (CEUR-WS.org)
48
order to be able to take a user-centred view on 2. Related Work
the Semantic Web [6].
However, before tasks can be identified, the
Due to the importance of a clear definition
first step is to determine who the intended users
of the user tasks when developing interactive
are and their context. There might be the
systems, especially if an UCD approach is
temptation to say that users are "everyone", but
followed, there are many studies of this kind.
UCD recommends dividing the target audience
Usually, they refer to the user tasks for a
into groups. Considered that the objective is to
concrete application. However, there are also
facilitate Semantic Web adoption among end-
studies that consider a range of applications in
users, this seems the target audience to focus
order to help defining guides or analysing
on. On the other hand, the context is any online
common practices.
application based on Semantic Web
When analysing existing work, we have
technologies, which seem the best channel for a
considered different studies at different scale
widespread adoption of the Semantic Web.
levels, from the more general online
In the context of this paper, end-user is
information systems, through Web information
defined as a user with no or limited knowledge
systems, to Semantic Web applications in
about Semantic Web technologies and
general and finally some specific Semantic
methodologies. We do not include in this user
Web scenarios. The objective is to not pass
profile domain experts, that might be also users
through potential tasks that might be considered
with limited knowledge about the Semantic
in the context of the Semantic Web but that
Web but who have specific needs related with
haven't been considered yet in that context.
the development of ontologies.
Therefore, starting from the broader context,
Once we have characterised the kind of
Heath et al. [8] propose a set of user tasks users
Semantic Web user we are interested in, it is
carry out on-line with information systems.
time to determine the tasks. As we are
They take a quite broad point of view as they
considering the Semantic Web as a whole, and
include the Web but also other Internet
not a specific Semantic Web application, the
application like electronic mail or instant
tasks should be generic and broad enough to
messaging. The list includes Locating,
accommodate tools that are not yet Semantic
Exploring, Grazing, Monitoring, Sharing,
Web enabled but that might be so in the future.
Notifying, Asserting, Discussing, Evaluating,
In order to make the range of tasks broad
Arranging and Transacting.
enough and avoid constraining our view to the
Locating is about users looking for
current state of development of the Semantic
something known or expected to exists.
Web, the focus should be broader than
Exploring refers to gathering information to
existing Semantic Web applications and studies
gain understanding or background. Grazing is
of Semantic Web user tasks. We also consider
moving speculatively without a specific goal.
user tasks in the context of the Web and even in
Monitoring is about checking known source
the context of information systems. This makes
expected to change. Sharing refers to making
it possible to check the consistency and
something available to others. Notifying is
coverage of the proposal. The range of user
informing others about something that happens.
tasks studies under consideration is presented in
Asserting is about making statements of fact or
Section 2.
opinion. Discussing refers to exchanging
From the analysis of these existing studies,
information on a topic with others. Evaluating
which range from Semantic Web to information
is determining if some information is true or
systems user tasks, we build our proposal of a
alternatives. Arranging is about coordinating
set of generic Semantic Web end-user tasks,
with third parties. Transacting is transferring
which is presented in Section 3. Then, in order
money.
to study these tasks deeper, we have then put
Getting into a more specific context, Kellar
them into practice in Section 4. We have
et al. [9] present a quite complete summary of
isolated them in the context of Rhizomer [7], a
studies about Web information systems user
platform that makes it possible to develop
tasks. In their web information task
Semantic Web enabled sites with content
classification, they identify a set of user tasks
management capabilities. Finally, Section 5
that are classified in three information goals:
presents the conclusions and the future work.
information seeking (Fact Finding, Info
49
Gathering and Browsing), information Action- to build a
exchange (Transacting and Communicating) oriented personalized portal
and information maintenance (Maintaining). tasks to manage research
Fact finding is usually a short task that tasks
stands for looking for specific pieces of Information to share pictures
sharing tasks with friends and
information. Information Gathering involves
family
the collection of information and Browsing is a Content Content to add new books
serendipitous task where users have no specific curators update tasks to a catalog of
goal in mind. In relation with the information published books
exchange goals, there are Transacting, which and edit the
stands for performing an on-line action that metadata of
often involves user/password authentication, previously added
and Communicating, connected to web-based ones
communication, e.g. e-mail or blogs. Content to provide
The last goal defined by Kellar is distribution information to
information maintenance that includes just one tasks museum visitors
user task, Maintaining. This task is about Ontologists Ontology to reorganise a
update tasks library
editing web resources in order to make them
categorisation
work properly, e.g. no broken links, and update scheme
them. Kellar et al. also consider a potential task, Ontology to map between
Monitoring as returning to a previously visited creation & different medical
page in order to obtain updated or dynamic mapping ontologies
information. However, they do not consider a
user tasks per se, but a task dimension, re- On the other hand, Mäkelä et al. [11] present
occurrence, that might be a characteristic of any three very generic tasks that need to be handled
of the previous user tasks, especially Browsing, in any information system with semantic
Transacting, Fact Finding and Information capabilities:
Gathering. • Semantic Content Consumption is about
If we concentrate now on Semantic Web consuming semantic content when users
applications, Battle [10] provides starting are searching, browsing or other tasks
points for describing Semantic Web users and like aggregating an RSS syndication
their tasks. ¡Error! No se encuentra el origen service.
de la referencia. shows the three high-level • Content Indexing stands for the tasks
categories of Semantic web users and the kind where ontologists or end-users produce
of tasks commonly associated with each group, semantic metadata by indexing and
together with an example for each task. Her publishing content with references to
characterisation of end-users is “users that do shared vocabularies. End-users may play
not know what the Semantic Web is and that do a role of content indexers when they are
not care as long as they can get what they need sharing videos or blogging.
quickly”. • Ontology Maintenance and Publishing
includes maintaining and publishing
Table 1 ontologies, which might be done by
Some proposed user groups and task types for dedicated information workers, i.e.
the Semantic Web [10] ontologists, or by end-users themselves
User Task Types Examples of tasks in Web 2.0 sites when they develop their
Group vocabulary in an ad-hoc manner
End users Information to look for a alongside indexing.
seeking tasks restaurant near the Finally, Sabou et. al [12] propose the
theater that will
analysis of very specific Semantic Web
still be open when
the movie is over.
applications from the point of view of users’
Information to organise the tasks. The kind of tasks under consideration in
synthesis agenda of a this work, Ontology Matching, Folksonomy
tasks conference Enrichment and Word Sense Disambiguation,
attendant. are quite complex and can be decomposed in
50
simpler ones. Moreover, these tasks are point of view of an end-user, i.e. without
targeted to users with some, or quite a lot, considering the particularities of the Semantic
knowledge about the Semantic Web. Web. Some examples of particular end-users’
tasks are then presented, together with
3. Semantic Web End-User Tasks references to the related tasks in the literature
previously analysed. Finally, the tasks are
analysed deeper, considering what the
From the analysis of the existing literature, Semantic Web might contribute to them, what
Semantic Web applications and our experience technologies and methodologies make them
with the Rhizomer platform [7], presented in possible and constitute and added value for
Section ¡Error! No se encuentra el origen de them.
la referencia., we have synthesized a set of All the considered tasks are basic ones.
generic user tasks that can assist Semantic Web Usually, in the context of concrete Semantic
developers while following a UCD approach. Web application, user tasks will be composed
As it has been mentioned in the introduction, if of a mixture of these basic tasks. The objective
this approach is followed, it is required to is to define a basic set of user tasks, that would
define user tasks before the development facilitate tasks analysis and UCD while being
process can continue. And prior to this, the easily combinable in order to derive more
target user must be defined. complex and specific user tasks. In order to
Though the objective is to define a set of illustrate these features, this categorisation of
generic tasks, not specific to a particular tasks will be put into practice in order to analyse
application, it is important to provide a minimal a generic platform for Semantic Web
characterisation of the user and avoid defining applications in Section ¡Error! No se
them as just any user. This is also motivated by encuentra el origen de la referencia., where
the fact that the objective is to define the we anticipate that basic user tasks will. In the
foundations for UCD of applications to be latter, the idea is that more specific user tasks
adopted by as many users as possible. The most will be detected, which might be built from one
populated user profile is end-users, that from or more of these basic Semantic Web user tasks.
the point of view of the Semantic Web will in
most cases stand for user with no or limited
knowledge about the Semantic Web 3.1. Search
technologies and methodologies [10].
One particularity is that we do not include in In general, this kind of tasks corresponds to
this category domain experts with some those when a user poses a query and obtains a
knowledge to be formalised as ontologies. They set of results that might be rendered in different
might have limited knowledge about the ways. We include here when the search might
Semantic Web particularities, but they might be delayed or repeated in the future, like in
not be considered end-users because they have monitoring scenarios.
very different objectives, and consequently
they will carry out quite different tasks in order 3.1.1. Examples
to accomplish them.
The users we are considering are used to
web and other Internet applications like Concrete examples of this task are when a
electronic mail or instant messaging. Therefore, user performs a simple keyword-based search
we should also consider a broader using a Web search engine, an advanced query
categorisation of tasks users carry out online. It that allows constraining different search
is necessary to consider a wider range of tasks dimensions, query by example, monitoring
because, although the Semantic Web is not elections results or a sports match, etc.
widely deployed right now, its opportunity is to
underpin the whole range of online user 3.1.2. Semantic Web Search
experiences and contribute new ways to do
things in a more usable and accessible way. In the context of the Semantic Web, the user
The next subsections present the set of can benefit from the implicit semantics when
generic Semantic Web end-user tasks we performing a search and get more accurate
propose. Each task is first considered from the results, i.e. higher precision and recall.
51
Moreover, the knowledge captured in music, viewing movie trailers, to follow a link
ontologies can be used in order to guide the user received in an e-mail, etc.
through the query construction process, in order
to facilitate query by example or results 3.2.2. Semantic Web Browse
presentation [13].
However, it is important to consider that
most users are used to perform this kind of tasks In the context of the semantic web, it is
by simple means like an input field where they possible to build a richer browsing experience
type the keywords they are interested in. because the underlying model is built from
Consequently, they might be confused if a more component of a smaller granularity, the triples
sophisticated form or syntax is required in order formed by a subject, a predicate and an object.
to pose a query. The combination of many triples builds up a
In some cases, and after some user testing, it graph. This graph might be browsed by
might be concluded that it is preferred to hide following the links between graph nodes
all these subtleties from the user, to keep a following different criteria, not but just
simple user interface, make use of the available showing the graph structure to the user [14].
semantics as part of the query engine internal For instance, those triples might come from
mechanisms and exploit the semantics from the different “documents”. All the triples from a
point of view of user interaction when document, identified by a URI might be
presenting the results and as part of the displayed to the user, who can follow the links
browsing user tasks, presented next. to external documents or browse the current
data if it is not displayed all at once. An
example of this behaviour is followed by
3.1.3. Related Work Tabulator [15]. It shows all the triples from a
Semantic Web document as an unfoldable tree.
This task includes Locating and Monitoring Another alternative is to provide a faceted
(Heath), is similar to Fact Finding view if the metadata being browsed is
and considers the temporal dimension of homogeneous, all the resources being browsed
monitoring scenarios (Kellar). It also considers have similar properties describing them. This is
Information Seeking (Battle) though some of possible using tools like Exhibit [16]. In
the examples Battle et al. propose may require addition to the explicit metadata structure, it is
other tasks, e.g. some sort of mash up in the also possible to take profit from the underlying
case of combining news from different news ontologies in order to derive new links among
sources. This task is also related to Semantic resources using mechanism like inference,
Content Consumption (Mäkelä), though it is clustering [17] or semantic queries to other
more specific because Semantic Content sources, for instance in order dynamically
Consumption also includes when users browse suggest related products based on the semantic
search results. Moreover, it is also a component description of the product being browsed.
of the complex user task Word Sense
Disambiguation (Sabou). 3.2.3. Related Work
3.2. Browse This task is related with both Exploring and
Grazing (Heath), and also with Browsing
This task is performed when the user moves (Kellar). Some of the examples of Information
through the information currently displayed. In Seeking (Battle) also include aspects related
the context of Web information systems this is with this task, e.g. learning more about a topic.
usually done by following the links that connect This task is also related to Semantic Content
the information to related information pieces. Consumption (Mäkelä), though it is more
specific because Semantic Content
3.2.1. Examples Consumption also includes searching.
Additionally, it is also a component of the
complex user task Word Sense Disambiguation
Concrete examples of this task are when a (Sabou).
user gets informed about the latest news,
reading blogs, entertainment, listening to
52
3.3. Annotate This task is connected with Asserting
(Heath), especially if we consider that the
statements made are metadata. It is also related
In this task the user describes a resource by
with a broader task that considers maintaining
providing properties and values that model its
information, Maintenance (Kellar), and also
characteristics, its relations to other resources,
with a more specific one that concentrates on
etc. This task includes providing a completely
updating content, Content Update (Battle).
new description but also complementing an
Considering tasks identified in the literature
existing one, modifying it or deleting some or
in the context of Semantic Web applications,
all of the attributes currently available.
this task is related with Content
Indexing (Mäkelä) in the sense that by that task
3.3.1. Examples semantic annotations are generated, but just as
long as some user intervention is required.
Concrete examples of this task are when a Otherwise, it is not a user task but a system task.
user tags a particular URL as it bookmarks it, It can be also related with Ontology
providing the title and the description of a Maintenance and Publishing (Mäkelä), though
video, geographically locating a photo, defining from the end-user characterisation we have
a user profile that includes personal details and made this task lays outside the set of user tasks
preferences, etc. under consideration.
3.3.2. Semantic Web Annotate 3.4. Mashup
The main particularity of this task, in the This task is about the user gathering
context of the Semantic Web, is that the different pieces of information and combining
annotations are based on a formal model. them in order to get something more than the
Consequently, annotations go beyond informal simple aggregation of those pieces. In other
and ambiguous tags into properties and values word, the user tries to get something from the
that might be constrained by the specifications aggregation of the data that cannot be or is
captured in schemas and ontologies. This difficult to obtain from those pieces separately,
feature is not just a way to facilitate machine without combining them into a coherent view.
processing; it might be also as a way to
facilitate the annotation task for the user. 3.4.1. Examples
The user can benefit from a domain
specification defining the available kinds of
Concrete examples of this task range from
resources, their properties depending on the
simple mashups such as combining a set of
resource type and the corresponding values. It
resources that are geographically situated in
is up to the user interface to guide the user
order to, for instance, which are the hotels near
through this knowledge space, dynamically
a venue, or resources with temporal dimension
constraining the choices to be made depending
that are arranged in a calendar or timeline in
on previous user actions, the context of use and
order to facilitate scheduling. More
the intended goals.
complicated scenarios are also possible, which
An example of a tool giving support to this
are based on combining the sources of
task in the context of the Semantic Web is the
information without a predefined output view,
Semantic Forms extension2 for Semantic
like combining a local list of publications with
MediaWiki [18], which takes profit from the
information about their impact factor in order to
underlying semantic models that structure
compute the overall impact, detect trends,
available types, properties and their values.
highlight the more relevant publications,
Tabulator also has recently introduced some
preparing a research activity report, etc.
support for metadata edition [19].
3.3.3. Related work 3.4.2. Semantic Web Mashup
2
http://www.mediawiki.org/wiki/Extension:Semantic_Forms
53
In the context of the Semantic Web, this task might be used in descriptions for many
involves combining two or more pieces of resources, some of which the user might not be
metadata about common resources in order to aware of it at the moment.
aggregate the available descriptions about Results from a mapping task might be used
them. It is also possible that the metadata is in order to facilitate or automate a mashup, or
about different resources, but in this case, they both tasks might be carried out alternatively and
should be similar in some sense in order to co-ordinately as a process where the user is
make possible the aggregation in some mashing up a set of resource descriptions and
dimension, e.g. they all have geographical during that process some mappings among the
coordinates or are situated in time and can be vocabularies being used are defined.
placed together in a map or timeline It might be the case that mappings are
respectively. derived from the analysis of the interaction of
The main benefit of Semantic Web many users, however this is a system task, the
technologies and methodologies for this task is user does not directly and consciously intervene
that as semantic metadata and ontologies are in this case. Here we are referring to tasks
available, it is easier to implement some sort of initiated by the user.
assistance for the user during the aggregation
process. The assistance may range from the 3.5.1. Examples
ability to propagate the aggregations made to
one particular resource property to all the uses
of that property in the metadata being mashed Examples of this task range from simple
up, like in the Potluck mashup tool [20], or scenarios like stating that two tags are
equivalent to more complex ones like relating
exploiting in a more automatic way the
different product categories or stating that all
available semantic metadata using semantic and
the things that one repository classifies as
statistical measures in order to provide a
papers are also a kind of publication as
preliminary mashup that the user might then
specified in a second repository vocabulary.
customise, like in the case of the semantic
information mashup tool Sig.ma [21].
3.5.2. Semantic Web Map
3.4.3. Related work
In the context of the Semantic Web, and also
considering that we have characterised all these
This task is related with, though slightly
tasks as those for an end-user, this task
more specific than, Information Gathering
corresponds to when the user defines simple
(Kellar) and includes the main characteristics of
mappings among classes, properties and values
both Evaluating and Arranging (Heath), which
specified in different ontologies. It is not about
might also involve search and browse but
exhaustive mappings among ontologies but
whose added value is about combining
instead about specific mappings that might be
information and extracting something more that
usually justified by the need of facilitating
its pure addition. It is also related with
mashing up some resource descriptions, or
Information Synthesis (Battle) and the Semantic
making the mashup more systematic.
Content Consumption user task (Mäkelä),
which is much wider and also includes
searching and browsing. 3.5.3. Related work
3.5. Map This task is a particular case of Ontology
Mapping (Battle), geared towards very simple
mappings and usually triggered by the system
This task takes place when the user defines
that asks users for confirmation because we
mappings among terms from different
focus on end-users that are not ontologists. It is
vocabularies. It is not constrained to a particular
also related with Ontology Maintenance and
set of resources like in the case of the Mashup
Publishing (Mäkelä) but that is also a task
task, and it does not operate at the level of
geared toward ontologists and domain experts,
particular resource descriptions. On the
not end-users. The same applies when
contrary, in this task, the user is working at the
considering Content Indexing (Mäkelä). The
level of the vocabularies. These vocabularies
54
same applies for Ontology Matching (Sabou) Annotate as the user does not perceive as being
while Folksonomy Enrichment might be easier describing something.
and more appropriate for end-users.
3.6.3. Related work
3.6. Share
This task is similar to Sharing (Heath) and
This task considers uploading, publishing, Information Sharing (Battle). There are not
updating and deleting pieces of content with the tasks related with this one in the studies of
intention of making them available to other Semantic Web tasks we have analysed. This
users, who can access the content from a place seems related with the fact that, as we have
and at a time individually chosen by them. This previously said, in the context of the Semantic
last statement allows to clearly distinguishing Web sharing semantic descriptions is a task
this task from the Communicate task, which is included in annotation tasks.
presented next.
This task is also differentiated from 3.7. Communicate
Annotate in the sense that what is added, edited
or removed is not metadata, data about data, but
data itself. This data will usually correspond to This task is about sharing information
different kinds of content that users want to directly with particular users, without the
share online, like videos, text, images, etc. intention of making it available to other users
from a place and at a time individually chosen
by them. The process is in this case driven by
3.6.1. Examples the user participating in this task as the emitter.
Examples of this task are posting a blog or 3.7.1. Examples
micro-blogging, participating in a forum,
sharing a photo in a social network, making a
file available through a Peer-to-Peer network, Examples of this task are to participate in a
etc. The participation in forums might also be chat, to send an e-mail, video-conference, etc.
seen as a communication task, described below, We have included here e-mails because they are
but the intention in most forums is to build a usually kept private and not intended to make
piece of information around a subject and to them publicly available to other users apart
make it available for later use. from the recipient. Moreover, the
communication is driven from the emitter as
long as the recipient has the e-mail client up and
3.6.2. Semantic Web Share listening.
In the context of the Semantic Web, this 3.7.2. Semantic Web Communicate
task, as long as related with data and not with
metadata, is not directly supported by Semantic
Web technologies and methodologies. Thought communication management is
However, it might be enriched by triggering fundamentally related with other tasks, like
some sort of content indexing and automatic searching for a specific e-mail, browsing
metadata generation. The metadata just conversations or annotating an e-mail, there
generated can then trigger an Annotate task, might be room for semantic technologies to
which allows the user editing and managing this play a role during this task. In any case, this is
metadata. one of the areas with less results coming from
However, there might be also scenarios the Semantic Web, and also the one that seems
where the distinction between data and to provide less room for them.
metadata is somehow blurred. For instance, in For instance, Haystack [23] is a tool for the
the context of Linked Data [22] publishing, web and desktop that helps the user manage
where bunches of semantic data are made whatever information a user considers
important, which includes communications
available without considering the specific
based on e-mail. The e-mail is processed and
resources being described, the task from the
semantically annotated in order to perform
point of view of the user is a Share, not an
55
communication management based on these place. For instance, by facilitating form filling
semantic annotations. while the user provides the required data to
complete the transaction. Another way to
3.7.3. Related Work support the transaction might be adapting the
results to user preferences and context, for
instance performing currency conversions
This task is related with Notifying and following user preferences.
Discussing (Heath).
3.8.3. Related Work
3.8. Transact
This task is present in two of the tasks lists
This is the last task, it is associated with user considered. There are Transacting (Heath) and
actions that provoke a change in the state of a Action-oriented (Battle) tasks.
real-world entity or of a resource in a system
outside the scope of the system the user is
interacting with. 4. The Rhizomer Platform Testbed
3.8.1. Examples Rhizomer3 is a platform based on Semantic
Web technologies that facilitates publishing
semantic data and building interactive Semantic
Examples of this task are buying a book, Web applications on top of it. Rhizomer differs
ordering a money transfer between bank from semantic web browsers in the sense that it
accounts, etc. The range of specific tasks is not just a browser application; there is also a
included in this category might vary a lot server part that allows defining datasets to be
depending on the interactive system attention is explored and which interacts with the SPARQL
focused on. If we concentrate on the user tasks endpoints holding the datasets semantic data.
for a specific application, any task that involves However, it is also capable of browsing data not
interacting with other systems might be stored in SPARQL endpoints but linked from
considered a transaction as a way to focus the them.
analysis. For instance, if some resource from
On the other hand, if a broader system is DBPedia [24] is used in a description stored in
considered, for instance any information
dataset published through Rhizomer, it is
system, the study might be detailed further and
possible to retrieve the associated metadata by
particular tasks among the ones presented
following the Linked Data principles and to
before might be identified as the goal of that perform all the user tasks available for local
interaction. In any case, actions that take place
data in a way totally transparent for the user.
in the real world, outside interactive
Moreover, Rhizomer also provides
information systems, might be considered
mechanisms that facilitate integrating external
transactions in the context of this end-user tasks
web services in a dynamic way. The external
proposal.
services to be integrated should be semantically
described and those descriptions should specify
3.8.2. Semantic Web Transact the kind of resources (classes) the get as input.
Rhizomer implements the mechanisms that
Together with communicate, this is the task allow associating at run time the resources
that might be less influenced by Semantic Web classified as being of the input type with the
technologies and methodologies. This is due to corresponding service.
the fact that by the definition of this task, they These associations are implemented as links
correspond to interactions of the user with that allow the user invoking the service, that
systems outside the Semantic Web. will receive the resource description as input,
In any case, applications might take profit process it and return some output. Usually, this
from these technologies and methodologies output will be HTML content to be integrated
while supporting this task before and after the into the interface. This way, it is easy to plug in
processing outside the Semantic Web takes external services that provide bridges to other
3
Rhizomer, https://rhizomer.rhizomik.net
56
services but also new ways to interact with • Mashup: mix two or more pieces of
resources. metadata about common resources, or
The backend is based on a web application resources similar in some sense, e.g.
providing an API to interact with the defined they all have geographical coordinates
datasets and the SPARQL endpoint that or are situated in time and can be placed
constitute them. The backend is built on top of together in a map or timeline
previous API and implemented using a web respectively.
framework based on HTML and JavaScript that • Map: define simple mappings between
makes the user interface highly interactive. concepts from different ontologies.
Rhizomer gives support to most of the users’ • Share: upload, update and delete
tasks presented in the previous section, with the pieces of content (HTML, images,
exception of the Communicate task: videos, etc.).
• Transact: generically, this task
• Search: pose semantic queries using includes any user action that change the
HTML forms, which are dynamically state of a real-world entity or of a
generated and obtain resource resource in a system outside Rhizomer.
descriptions rendered as HTML, as
shown in Figure 1. 5. Conclusions and Future Work
• Browse: navigate through the graph of
data retrieving fragments of
manageable size and rendering them as In order to make the Semantic Web reach
interactive HTML, as shown in Figure “real world” end-users, special care must be
2. placed in making Semantic Web applications
more usable and accessible. It is possible to take
• Annotate: provide new semantic
profit from the experience accumulated by the
metadata describing a resource, or edit
Human-Computer Interaction community and
existing one, using HTML forms that
apply User-Centred Design approaches.
assist the user during this process.
Figure 1. Rhizomer’s faceted view featuring search
57
Figure 2. Rhizomer browsing Linked Data
Web end-user tasks proposed is based on the
This kind of approaches place the user at the analysis of existing tasks inventories for the
centre of the development process and start by Web and even for online information systems
defining the user, its context and the tasks to be in general.
performed by them in order to meet their needs. The analysis is complemented with the
These tasks are specific to a particular experience gained implementing a Semantic
interactive application, but it very useful to Web platform and a Semantic Web application
define a set of common user tasks in the context based on that platform. Additionally, a list of
of a particular domain, e.g. Web information Semantic Web capabilities has been used in
systems, in order to establish UCD guidelines order to complement the process of checking
and common interaction patterns for that the consistency and coverage of proposed set of
domain. end-user tasks.
This is the main aim of this work, to identify The set of tasks includes Search, Browse,
a set of common user tasks for the Semantic Annotate, Mashup, Map, Share, Communicate
Web. However, it is important to concretise the and Transact. Each of these tasks has been
user profile, it is not enough to say that tasks are described avoiding technological
for any user. In this case, as the aim is to considerations and then presented from the
contribute to the widespread adoption of the point of view of the Semantic Web. They are
Semantic Web, the target user is the end-user. also related to the tasks proposed in the
This is a user with no or quite limited literature under consideration.
knowledge about the Semantic Web. The Finally, the set of tasks has been put into
context is any online application based on practice and the Rhizomer platform in order to
Semantic Web technologies. detect if they give support to these end-user
Once the user and the context are defined, it tasks and that not additional ones are required.
is time to determine the user tasks. In order to This analysis also allows, in the case of the
consider a broad range of user tasks, it is Rhizomer platform, presenting how these tasks
important to avoid constraining the analysis to are materialised in the context of the platform
the current Semantic Web. The set of Semantic as different interaction patterns.
58
Additionally, it is shown how, as it might be a user tasks, once decomposed into its basic
anticipated, the platform user tasks are the basic components.
ones while for the application build on top of For instance, Welie proposes patterns for
Rhizomer, the more complex user tasks can be Browsing or Searching. The objective is to
decomposed into basic user tasks from the build on top of these pattern libraries and
proposed set. classify them considering the proposed
Future work concentrates now on the next Semantic Web end-user tasks. Many of them
natural step when following a UCD approach. might be mapped directly from the Web domain
Once the user tasks have been identified, it is to the Semantic Web, like Welie’s patterns for
really useful to have an inventory of interaction Search and Browse, two tasks near clear
patterns that give support to these user tasks as equivalents in the Semantic Web. In any case,
a guideline. There are many lists of interaction they must be studied in detail, new
patterns, though most of them focus on Web opportunities should be detected and there is
systems or other interactive systems without also room for novel interaction patterns that the
particularising their proposal in the context of Semantic Web might make possible. On the
Semantic Web applications and Semantic Web other hand, our analysis against related work
user tasks. specific for Web information systems shows
Our aim is to build an inventory of Semantic that the user tasks where the contribution of
Web interaction patterns starting from existing Semantic Web technologies might be more
inventories, e.g. Tidwell’s [25], van Welie’s important, because they a less consider or not
[26], Toxboe’s [27] or Crumlish & Malone's considered at all, are Annotate, Mashup and
[28]. Some of them are structured in part using Map.
user tasks as the way of classifying the patterns,
making it possible to use them as a reference 6. References
when implementing the interaction that support
[1] M.D. Lytras, R. García. Semantic Web 2013, pp. 1025-1045. DOI: 10.3217/jucs-
applications: a framework for industry and 019-08
business exploitation–What is needed for [6] R. García, R. Gil, E. Bakke, D.R. Karger.
the adoption of the Semantic Web from the A benchmark for end-user structured data
market and industry. International Journal exploration and search user interfaces.
of Knowledge and Learning, 4(1), 2008, Journal of Web Semantics, 65, 2020. DOI:
pp. 93-108. DOI: 10.1016/j.websem.2020.100610
10.1504/IJKL.2008.019739 [7] J.M. Brunetti, R. García. User-centered
[2] T. Heath, J. Domingue and P. Shabajee: design and evaluation of overview
"User interaction and uptake challenges to components for semantic data exploration.
successfully deploying Semantic Web Aslib Proceedings, 2014, 66(5), 2014, pp.
technologies". In Proc. 3rd International 519-536. DOI: 10.1108/AJIM-12-2013-
Semantic Web User Interaction 0153
Workshop, Athens, Georgia, USA, 2006. [8] T. Heath, M. Dzbor, E. Motta: "Supporting
[3] m. c. schraefel, J. Golbeck, D. Degler, A. User Tasks and Context: Challenges for
Bernstein, L. Rutledge, Semantic web user Semantic Web Research", in: Proc.
interactions: exploring hci challenges, in: ESWC2005 Workshop on End-User
CHI Extended Abstracts, 2008, pp. 3929- Aspects of the Semantic Web
3932. (UserSWeb), 2005.
[4] ISO/IEC 25010-3. Systems and software [9] M. Kellar, C. Watters, M. Shepherd. A
engineering: Software product quality and Goal-based Classification of Web
system quality in use models. ISO Press, Information Tasks. In 69th Annual
2011. Meeting of the American Society for
[5] J.L. González-Sánchez, R. García, J.M. Information Science and Technology,
Brunetti, R. Gil, J.M. Gimeno. Using Austin, US, 3-8 November 2006.
SWET-QUM to compare the quality in use [10] L. Battle, Preliminary Analysis of Users
of semantic web exploration tools. Journal and Tasks for the Semantic Web, Semantic
of Universal Computer Science, 19(8), Web User Interaction Workshop,
59
[18] M. Krötzsch, D. Vrandečić, M. Völkel,
International Semantic Web Conference, Semantic MediaWiki, in: The Semantic
Athens, GA, 2006. Web - ISWC 2006, Heidelberg, DE,
[11] E. Mäkelä, K. Viljanen, O. Alm, J. Springer, 2006, pp. 935-942.
Tuominen, O. Valkeapää, T. Kauppinen, J. [19] T. Berners-Lee, J. Hollenbach, K. Lu, J.
Kurki, R. Sinkkilä, T. Känsälä, R. Presbrey, E. Pru d'ommeaux, M.C.
Lindroos, O. Suominen, T. Ruotsalo and schraefel, Tabulator Redux: Writing Into
E. Hyvönen. Enabling the Semantic Web the Semantic Web, Southampton, UK,
with Ready-to-Use Web Widgets. FIRST - Electronics and Computer Science,
First Industrial Results of Semantic University of Southampton, 2007.
Technologies Workshop, at the [20] D. Huynh, R. Miller, Robert, and D.R.
ISWC+ASWC Conference, Busan, Korea, Karger, Potluck: Data Mash-Up Tool for
November 11-15, 2007. Casual Users, 6th International Semantic
[12] M. Sabou, J. Garcia, S. Angeletou, M. Web Conference (ISWC), November
D'Aquin and E. Motta. Evaluating the 2007.
Semantic Web: A Task-based Approach” [21] M. Catasta, R. Cyganiak, G. Tummarello,
in The 6th International Semantic Web Towards ECSSE: live Web of Data search
Conference and the 2nd Asian Semantic and integration, Semantic Search 2009
Web Conference, 2007. Workshop, Madrid, Spain, 2009.
[13] M.L. Wilson, m.c. schraefel, R.W. White, [22] C. Bizer, T. Heath, K. Idehen, T. Berners-
Evaluating Advanced Search Interfaces Lee, Linked data on the web
using Established Information-Seeking (LDOW2008), en: Proceeding of the 17th
Models, Journal of the American Society International Conference on World Wide
for Information Science and Technology, Web, Beijing, China, ACM, 2008: págs.
(2009) in press. 1265-1266.
[14] D.R. Karger, m.c. schraefel, The Pathetic [23] D. Quan, D. Huynh, D. Karger, Haystack:
Fallacy of RDF, SWUI 2006 - 3rd A Platform for Authoring End User
International Semantic Web User Semantic Web Applications, en: The
Interaction Workshop, November 2006. SemanticWeb - ISWC 2003, LNCS Vol
[15] T. Berners-Lee et. al., Tabulator: 2870, Springer, 2003, pp. 738-753.
Exploring and Analyzing linked data on [24] J. Lehmann, et al. DBpedia–a large-scale,
the Semantic Web, in: Procedings of the multilingual knowledge base extracted
The 3rd International Semantic Web User from Wikipedia. Semantic web, 6(2),
Interaction Workshop, SWUI’06, Athens, 2015, pp. 167-195. DOI: 10.3233/SW-
Georgia, 2006. 140134
[16] D.F. Huynh, D.R. Karger, R.C. Miller, [25] J. Tidwell, Designing Interfaces: Patterns
Exhibit: lightweight structured data for Effective Interaction Design, O'Reilly,
publishing, en: Proceedings of the 16th 2005.
International Conference on World Wide [26] M. Welie. A Pattern Library for Interaction
Web, Banff, Alberta, Canada, ACM, 2007, Design. Available from:
pp. 737-746. http://www.welie.com
[17] L. Rutledge, J. van Ossenbruggen, L. [27] A. Toxboe. User Interface Design patterns.
Hardman, Making RDF Presentable - Available from: http://ui-patterns.com
Global and Local Semantic Web [28] C. Crumlish, E. Malone. Designing social
Browsing, in: Proceedings of The interfaces: Principles, patterns, and
Fourteenth International World Wide Web practices for improving the user
Conference, WWW’05,ACM Press, experience. O'Reilly Media, 2009.
Chiba, Japan, 2005, pp. 199-206.