Wilko van Hoek

Zeljko Carevic, Maria Lusky, Wilko van Hoek et al.

In this paper we present the results of a user study on exploratory search activities in a social science digital library. We conducted a user study with 32 participants with a social sciences background -- 16 postdoctoral researchers and 16 students -- who were asked to solve a task on searching related work to a given topic. The exploratory search task was performed in a 10-minutes time slot. The use of certain search activities is measured and compared to gaze data recorded with an eye tracking device. We use a novel tree graph representation to visualise the users' search patterns and introduce a way to combine multiple search session trees. The tree graph representation is capable to create one single tree for multiple users and to identify common search patterns. In addition, the information behaviour of students and postdoctoral researchers is being compared. The results show that search activities on the stratagem level are frequently utilised by both user groups. The most heavily used search activities were keyword search, followed by browsing through references and citations, and author searching. The eye tracking results showed an intense examination of documents metadata, especially on the level of citations and references. When comparing the group of students and postdoctoral researchers we found significant differences regarding gaze data on the area of the journal name of the seed document. In general, we found a tendency of the postdoctoral researchers to examine the metadata records more intensively with regards to dwell time and the number of fixations.

Daniel Hienert, Wilko van Hoek, Alina Weber et al.

One of the main challenges in Interactive Information Retrieval (IIR) evaluation is the development and application of re-usable tools that allow researchers to analyze search behavior of real users in different environments and different domains, but with comparable results. Furthermore, IIR recently focuses more on the analysis of whole sessions, which includes all user interactions that are carried out within a session but also across several sessions by the same user. Some frameworks have already been proposed for the evaluation of controlled experiments in IIR, but yet no framework is available for interactive evaluation of search behavior from real-world information retrieval (IR) systems with real users. In this paper we present a framework for whole-session evaluation that can also utilize these uncontrolled data sets. The logging component can easily be integrated into real-world IR systems for generating and analyzing new log data. Furthermore, due to a supplementary mapping it is also possible to analyze existing log data. For every IR system different actions and filters can be defined. This allows system operators and researchers to use the framework for the analysis of user search behavior in their IR systems and to compare it with others. Using a graphical user interface they have the possibility to interactively explore the data set from a broad overview down to individual sessions.

Wilko van Hoek, Philipp Mayr

Although various visual interfaces for digital libraries have been developed in prototypical systems, very few of these visual approaches have been integrated into today's digital libraries. In this position paper we argue that this is most likely due to the fact that the evaluation results of most visual systems lack comparability. There is no fix standard on how to evaluate visual interactive user interfaces. Therefore it is not possible to identify which approach is more suitable for a certain context. We feel that the comparability of evaluation results could be improved by building a common evaluation setup consisting of a reference system, based on a standardized corpus with fixed tasks and a panel for possible participants.

Wilko van Hoek, Wei Shen, Philipp Mayr

This paper presents an analysis of the user behavior of two different domain-specific repositories. The web analytic tool etracker was used to gain a first overall insight into the user behavior of these repositories. Moreover, we extended our work to describe an apache web log analysis approach which focuses on the identification of the user behavior. Therefore the user traffic within our systems is visualized using chord diagrams. We could find that recommendations are used frequently and users do rarely combine searching with faceting or filtering.

Wilko van Hoek

As users advance in their search within a system, different queries are conducted and various results are examined by them. These objects form an implicit individual library representing the acquired knowledge. In our research we aim to supply the user with visualizations of the search history and interaction methods to organize the history. The fundamental question is what role search history exploration can play in the users search process. In this paper we want to introduce Ideas of a prototypical system for search history exploration and discuss methods to address the questions mentioned above.

Wilko van Hoek, Philipp Mayr

In this paper we present an overview of several visualization techniques to support the search process in Digital Libraries (DLs). The search process typically can be separated into three major phases: query formulation and refinement, browsing through result lists and viewing and interacting with documents and their properties. We discuss a selection of popular visualization techniques that have been developed for the different phases to support the user during the search process. Along prototypes based on the different techniques we show how the approaches have been implemented. Although various visualizations have been developed in prototypical systems very few of these approaches have been adapted into today's DLs. We conclude that this is most likely due to the fact that most systems are not evaluated intensely in real-life scenarios with real information seekers and that results of the interesting visualization techniques are often not comparable. We can say that many of the assessed systems did not properly address the information need of cur-rent users.