Thomas Low

What are the real differences of children's and adults' web search

We present first results of a logfile analysis on web search engines for children. The aim of this research is to analyse fundamental facts about how childrens web search behaviour differs from that of adults. We show differences to previous results, which are often based on small lab experiments. Our large-scale analysis suggests that children search queries are more information-oriented and shorter on average. Children indeed make a lot of spelling errors and often repeat searches and revisit web pages.

The Hubness Phenomenon: Fact or Artifact?

The hubness phenomenon, as it was recently described, consists in the observation that for increasing dimensionality of a data set the distribution of the number of times a data point occurs among the k nearest neighbors of other data points becomes increasingly skewed to the right. As a consequence, so-called hubs emerge, that is, data points that appear in the lists of the k nearest neighbors of other data points much more often than others. In this paper we challenge the hypothesis that the hubness phenomenon is an effect of the dimensionality of the data set and provide evidence that it is rather a boundary effect or, more generally, an effect of a density gradient. As such, it may be seen as an artifact that results from the process in which the data is generated that is used to demonstrate this phenomenon. We report experiments showing that the hubness phenomenon need not occur in high-dimensional data and can be made to occur in low-dimensional data.

Visual berrypicking in large image collections

Exploring image collections using similarity-based two-dimensional maps is an ongoing research area that faces two main challenges: with increasing size of the collection and complexity of the similarity metric projection accuracy rapidly degrades and computational costs prevent online map generation. We propose a prototype that creates the impression of panning a large (global) map by aligning inexpensive small maps showing local neighborhoods. By directed hopping from one neighborhood to the next the user is able to explore the whole image collection. Additionally, the similarity metric can be adapted by weighting image features and thus users benefit from a more informed navigation.

Towards Identifying User Intentions in Exploratory Search using Gaze and Pupil Tracking

Exploration in large multimedia collections is challenging because the user often navigates into misleading directions or information areas. The vision of our project is to develop an assistive technology that is able to support the individual user and enhance the efficiency of an ongoing exploratory search. Such a technical search aid should be able to find out about the users current interests and goals. Respective parameters can be found in the central and in the peripheral nervous system as well as in overt behavior. Therefore, we aim at using eye movements, pupillometry and EEG to assess respective information. Here, we describe the set-up and the first results of a preliminary user study investigating the effects of searching an image collection on eye movements and pupil dilations. First data show that numbers of fixation, fixation durations as well as pupil dilations differ systematically when looking at a subsequently selected target as compared with not selected items. These results support our vision that further research additionally investigating EEG can in fact result in better predicting the searchers goals and next choices.

Exploring Large Movie Collections: Comparing Visual Berrypicking and Traditional Browsing

We compare Visual Berrypicking, an interactive approach allowing users to explore large and highly faceted information spaces using similarity-based two-dimensional maps, with traditional browsing techniques. For large datasets, current projection methods used to generate maplike overviews suffer from increased computational costs and a loss of accuracy resulting in inconsistent visualizations. We propose to interactively align inexpensive small maps, showing local neighborhoods only, which ideally creates the impression of panning a large map. For evaluation, we designed a web-based prototype for movie exploration and compared it to the web interface of The Movie Database (TMDb) in an online user study. Results suggest that users are able to effectively explore large movie collections by hopping from one neighborhood to the next. Additionally, due to the projection of movie similarities, interesting links between movies can be found more easily, and thus, compared to browsing serendipitous discoveries are more likely.

Exploration of Web Search Results Based on the Formal Concept Analysis

In this paper, we present an approach to support exploratory search by structuring search results based on concept lattices, which are created on the fly using advanced methods from the area of Formal Concept Analysis (FCA). The main aim of the approach is to organize query based search engine results (e.g. web documents) as a hierarchy of clusters that are composed of documents with similar attributes. The concept lattice provides a structured view on the query-related domains and hence can improve the understanding of document properties and shared features. Additionally, we applied a fuzzy extension of FCA in order to support the usage of different types of attributes within the analyzed query results set. The approach has been integrated into an interactive web search interface. It provides a smooth integration of keyword-based web search and interactive visualization of concept lattice and its concepts in order to support complex search tasks.