User-guided Disambiguation for Semantic-enriched Search

In this thesis, we develop, implement and evaluate a strategy for user-guided disambiguation for semantic-enriched search. We use the prototype system Capisco that combines some features of traditional text-based search engines and semantic search engines. Unlike many semantic search approaches that require formulating queries in quite complex semantic languages, the Capisco system is a keyword-based search engine. In this work, we focus on the user-guided disambiguation which helps to capture the users’ information needs. The user-guided disambiguation developed in this thesis explores the semantic meanings for a user-provided keyword and displays these to the users for selection. We explored three different orderings in which the possible keyword meanings may be shown. Using our newly-developed disambiguation interface, the user selects one or several of these meanings from the list offered. The selected semantic meanings are then transferred to the search engine to identify matching documents. This thesis provides an analysis of related work on search interfaces in semantic search, and in methods for semantic disambiguation. We developed the concept of user-guided disambiguation and implemented this concept in a prototype that explored three interface variations. We executed a user study on the three interface alternatives. Finally, we discuss the insights gained during this project, compare our approach to existing literature, and explore possible future work

DESIGN WITH EMOTION: IMPROVING WEB SEARCH EXPERIENCE FOR OLDER ADULTS

Research indicates that older adults search for information all together about 15% less than younger adults prior to making decisions. Prior research findings associated such behavior mainly with age-related cognitive difficulties. However, recent studies indicate that emotion is linked to influence search decision quality. This research approaches questions about why older adults search less and how this search behavior could be improved. The research is motivated by the broader issues of older users\u27 search behavior, while focusing on the emotional usability of search engine user interfaces. Therefore, this research attempts to accomplish the following three objectives: a) to explore the usage of low level design elements as emotion manipulation tools b) to seamlessly integrate these design elements into currently existing search engine interfaces, and finally c) to evaluate the impact of emotional design elements on search performance and user satisfaction. To achieve these objectives, two usability studies were conducted. The aim of the first study was to explore emotion induction capabilities of colors, shapes, and combination of both. The study was required to determine if the proposed design elements have strong mood induction capabilities. The results demonstrated that low level design elements such as color and shape have high visceral effects that could be used as potentially viable alternatives to induce the emotional states of users without the users having knowledge of their presence. The purpose of the second study was to evaluate alternative search engine user interfaces, derived from this research, for search thoroughness and user preference. In general, search based performance variables showed that participants searched more thoroughly using interface types that integrate angular shape features. In addition, user preference variables also indicated that participants seemed to enjoy search tasks using search engine interfaces that used color/shape combinations. Overall, the results indicated that seamless integration of low level emotional design elements into currently existing search engine interfaces could potentially improve web search experience

Using eye tracking for evaluation of information visualisation in web search interfaces

Search result organization and presentation is an important component of a web search system, and can have a substantial impact on the ability of users to find useful information. Most web search result interfaces include textual information, including for example the document title, URL, and a short query-biased summary of the content. Recent studies have developed various novel visual summaries, aiming to improve the effectiveness of search results. In this thesis, the impact and efficacy of presenting additional visual summaries are investigated through a series of four studies. User interaction with the search results was captured using eye tracking data. In the first study we compare the effectiveness of three publicly available search interfaces for supporting navigational search tasks. The three interfaces varied primarily in the proportion of visual versus textual cues that were used to display a search result. Our analysis shows that users' search completion time varies greatly among interfaces, and an appropriate combination of textual and visual information leads to the shortest search completion time and the least number of wrong answers. Another outcome of this experiment is the identification of factors that should be accounted for in subsequent, more controlled, experiments with visual summaries, including the size of the visual summaries and interface design. An understanding of the features and limitations of the eye tracker, particularly for IR studies, was also obtained. To obtain a richer understanding of a user's information seeking strategies and the impact of presenting additional visual summaries, five interfaces were designed: text-only, thumbnail, image, tag and visual snippet. In the second study, fifty participants carried out searches on five informational topics, using the five different interfaces. Findings show that visual summaries significantly impact on the behaviour of users, but not on their performance when predicting the relevance of answer resources. In the third study, fifty participants carried out five navigational topics using the five different interfaces. The results show that apart from the salient image interface, users perform statistically significantly better in terms of time required and effort required to answer given navigational search topics when additional visual summaries are presented. The fourth study was conducted with both navigational and informational topics, for a more detailed comparison between the best-performing interfaces identified in the previous studies: salient images for informational searches, and thumbnails for navigational searches. The findings confirm our previous results. Overall, the salient image interface can significantly increase user performance with informational topics, while thumbnails can help users to predict relevant answers, in a significantly shorter time, with navigational search topics

Study of result presentation and interaction for aggregated search

The World Wide Web has always attracted researchers and commercial search engine companies due to the enormous amount of information available on it. "Searching" on web has become an integral part of today's world, and many people rely on it when looking for information. The amount and the diversity of information available on the Web has also increased dramatically. Due to which, the researchers and the search engine companies are making constant efforts in order to make this information accessible to the people effectively. Not only there is an increase in the amount and diversity of information available online, users are now often seeking information on broader topics. Users seeking information on broad topics, gather information from various information sources (e.g, image, video, news, blog, etc). For such information requests, not only web results but results from different document genre and multimedia contents are also becoming relevant. For instance, users' looking for information on "Glasgow" might be interested in web results about Glasgow, Map of Glasgow, Images of Glasgow, News of Glasgow, and so on. Aggregated search aims to provide access to this diverse information in a unified manner by aggregating results from different information sources on a single result page. Hence making information gathering process easier for broad topics. This thesis aims to explore the aggregated search from the users' perspective. The thesis first and foremost focuses on understanding and describing the phenomena related to the users' search process in the context of the aggregated search. The goal is to participate in building theories and in understanding constraints, as well as providing insights into the interface design space. In building this understanding, the thesis focuses on the click-behavior, information need, source relevance, dynamics of search intents. The understanding comes partly from conducting users studies and, from analyzing search engine log data. While the thematic (or topical) relevance of documents is important, this thesis argues that the "source type" (source-orientation) may also be an important dimension in the relevance space for investigating in aggregated search. Therefore, relevance is multi-dimensional (topical and source-orientated) within the context of aggregated search. Results from the study suggest that the effect of the source-orientation was a significant factor in an aggregated search scenario. Hence adds another dimension to the relevance space within the aggregated search scenario. The thesis further presents an effective method which combines rule base and machine learning techniques to identify source-orientation behind a user query. Furthermore, after analyzing log-data from a search engine company and conducting user study experiments, several design issues that may arise with respect to the aggregated search interface are identified. In order to address these issues, suitable design guidelines that can be beneficial from the interface perspective are also suggested. To conclude, aim of this thesis is to explore the emerging aggregated search from users' perspective, since it is a very important for front-end technologies. An additional goal is to provide empirical evidence for influence of aggregated search on users searching behavior, and identify some of the key challenges of aggregated search. During this work several aspects of aggregated search will be uncovered. Furthermore, this thesis will provide a foundations for future research in aggregated search and will highlight the potential research directions