Visualisation of Semantic Enrichment

Alexa Schlegel1, Ralf Heese1, Annika Hinze2

1Freie Universitaet Berlin, Germany

aschle, heese @inf.fu-berlin.de 2University of Waikato, New Zealand

hinze@cs.waikato.ac.nz

Abstract: Automatically creating semantic enrichments for text may lead to

annotations that allow for excellent recall but poor precision. Manual enrichment is

potentially more targeted, leading to greater precision. We aim to support non-

experts in manually enriching texts with semantic annotations. Neither the

visualisation of semantic enrichment nor the process of manually enriching texts

has been evaluated before. This paper presents the results of our user study on

visualisation of text enrichment during the annotation process. We performed

extensive analysis of work related to the visualisation of semantic annotations. In a

prototype implementation, we then explored two layout alternatives for visualising

semantic annotations and their linkage to the text atoms. Here we summarise and

discuss our results and their design implications for tools creating semantic

annotations.

1 Introduction

With semantic technologies, annotations are no longer about the content (as in Web 2.0

tagging) but become part of the content. Such semantic enrichment typically consists of

an annotated text passage (text atom) and related information (annotation). Clear

visualisation of enrichment, that is, indication of text atom and linkage to annotation, is

important for both the definition of annotations and the reading of enriched text.

Furthermore, it is essential for the acceptance of semantic technologies that non-experts

are enabled to produce and consume semantically enriched content.

Here we focus on the visualisation of enrichment during the annotation process. To the

best of our knowledge, neither the visualisation of semantic enrichment nor the process

of manually enriching texts has been evaluated before. Additionally, research on

presentation of semantically annotated documents typically targets the rather passive

reception aspects of data visualisation. Our research is motivated by experiences in two

projects, TIP and loomp, addressing the annotation of content by non-experts. TIP is a

mobile tourist information system that provides different information depending on a

user’ interests [Hin09]. Textual information in TIP has to undergo a semantic enrichment

process to be prepared for this interest-based filtering [Hsi08]. Loomp is a tool for the

management of semantic enrichment, which we applied to texts (predominantly) relating

to museums and their exhibitions [Luc09]. In loomp, users enrich texts semantically by

linking text passages to concepts, thus forming annotations with additional, structured

1047

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1052

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1053

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1054

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1055

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ring of bars

1056

During the study it was noted that overlapping annotations constitute a considerate

proportion of all created annotations (used by 8 of 12; up to 30% of all annotations). In

the guided interviews, we observed that the participants saw the bar layout to be more

suitable for annotating larger text passages because many (small) bars on the left side

potentially make the interface less clear. Participants also found that the bar layout was

somewhat imprecise as atoms are only identified by line but not by position in each line.

However, the bar layout was found to be well suited for reading and annotating since

texts themselves do not contain any highlighting.

Participants found the border layout to be more suited for annotating short text passages

because they could easily recognize the atoms, and the relationship between atoms and

annotations was clear. However, participants noted that users may get confused by the

borders if they are confronted with too many atoms.

6 Conclusion and Future Work

The success and rapid uptake of Web 2.0 concepts was largely due to and driven by the

availability of applications for non-expert users (i.e., users with little knowledge about

Web technologies). We believe that the success of the Semantic Web similarly depends

on the availability of applications for non-expert users (i.e., users with little knowledge

about semantic concepts and technologies). Many semantic web researchers focus on

creating applications for producing and consuming semantically enriched content.

However, only few ensure the usability of their user interfaces for the large group of

non-expert users.

In this paper we present our analysis of visual tools for creating annotations and describe

the results of an initial user study on the highlighting of annotations. The results of our

study form a first step towards formulating recommendations and best-practice examples

for the design of annotation systems with manual components.

The indication of overlapping annotations was identified as the main issue for

visualisation of annotations. None of the tools and annotation interfaces had been

previously evaluated for their ease of use. In our user study, two layout alternatives for

the visualisation of text atoms and their linkage to annotations. Our user study confirmed

that overlapping annotations constitute a considerate proportion of all created

annotations. They were identified as part of a typical annotation process and should not

be treated as special cases. The border layout supports clear identification of overlapping

annotations, whereas their identification is more complicated in the bar layout. We also

found that the bar layout is more suitable for annotating larger text passages whereas the

border layout is more suitable for annotating words and short passages. We therefore

recommend that systems should implement two views on annotated texts: One view for

unhindered reading, a quick overview of the text and locating atoms and annotations at a

glance (e.g., bar layout) and another one for creating annotations in the text and

retrieving detailed information about the annotated text passages (e.g., border layout).

1057

The work presented in this paper considered mainly the visualisation of (simple

semantic) annotations (e.g., assigning a category). However, full semantic mark-up

requires the additional assignment of semantic identifiers. The understanding of complex

semantic annotations (e.g., assigning and interpreting the linkage to resources) by non-

expert users is more complicated and needs to be explored further. Moreover, so far only

annotations created by single users were analysed. The concurrent annotation of texts by

a group of users (e.g., in a crowd-sourcing approach) will most likely lead to more

overlapping and potentially contradicting annotations. Appropriate resolution of these

cases still needs further research.

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[Hsi08] Ping-Ju Hsieh. Administration Service for the Tourist Information System. Master’s

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[Luc09] Markus Luczak-Rösch and Ralf Heese. Linked data authoring for non-experts. In

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[Muh94] Thomas Muhr. ATLAS.ti: Ein Werkzeug für die Textinterpretation. In Schriften zur

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