Alia Amin’s research while affiliated with Centrum Wiskunde & Informatica and other places

Comparison search is an information seeking task where a user examines individual items or sets of items for similarities and differences. While this is a known information need among experts and knowledge workers, appropriate tools are not available. In this paper, we discuss comparison search in the cultural heritage domain, a domain characterized by large, rich and heterogeneous data sets, where different organizations deploy different schemata and terminologies to describe their artifacts. This diversity makes meaningful comparison difficult. We developed a thesaurus-based comparison search application called LISA, a tool that allows a user to search, select and compare sets of artifacts. Different visualizations allow users to use different comparison strategies to cope with the underlying heterogeneous data and the complexity of the search tasks. We conducted two user studies. A preliminary study identifies the problems experts face while performing comparison search tasks. A second user study examines the effectiveness of LISA in helping to solve comparison search tasks. The main contribution of this paper is to establish design guidelines for the data and interface of a comparison search application. Moreover, we offer insights into when thesauri and metadata are appropriate for use in such applications.

We present a web -based diary study on location -based search behavior using a mobile search engine. To capture users' location -based search behavior in a ubiquitous setting, we use a web-based diary tool that collects users' detailed mobile search activity, their location and diary entries. This method enables us to capture users' explicit behavior (query made), their implicit intention (motivation behind search) and the context (spatial, temporal, and social) in which,the search was carried out. The results of the,study show that people tend to stick closely to regularly used routes and regularly visited places, e.g. home and work. We also found that most location -based searches are conducted,while in the presence of others. We summarize our findings and offer suggestions to improve,location-based search by using features such as location -based service mash-ups. Keywords: location -based search, local search, mobile search, diary study

State of the art web search systems enable aggregation of information from many sources. Users are challenged to as- sess the reliability of information from dierent sources. We report on an empirical user study on the eect of display- ing credibility ratings of multiple cultural heritage sources (e.g. museum websites, art blogs) on users' search perfor- mance and selection. The results of our online interactive study (N = 122) show that when explicitly presenting these ratings, people become signicantly more condent in their selection of information from aggregated results.

In this paper, we describe one of the largest multi-site interactive video retrieval experiments conducted in a laboratory setting. Interactive video retrieval performance is difficult to cross-compare as variables exist across users, interfaces and the underlying retrieval engine. Conducted within the framework of TRECVID 2008, we completed a multi-site, multi-interface experiment. Three institutes participated involving 36 users, 12 each from Dublin City University (DCU, Ireland), University of Glasgow (GU, Scotland) and Centrum Wiskunde \& Informatica (CWI, the Netherlands). Three user interfaces were developed which all used the same search service. Using a latin squares arrangement, each user completed 12 topics, leading to 6 TRECVID runs per site, 18 in total. This allowed us to isolate the factors of users and interfaces from retrieval performance. In this paper we present an analysis of both the quantitative and qualitative data generated from this experiment, demonstrating that for interactive video retrieval with ``novice'' users, performance can vary by up to 300\% for the same system using different sets of users, whilst differences in performance of interface variants was in comparison not statistically different. Our results have implications for the manner in which interactive video retrieval experiments using non-expert users are evaluated. The primary focus of this paper is in highlighting that non-expert users generate very large performance fluctuations, which may either mask or create system variability. The discussion of why this happened is not covered by this paper.

Embodied social agents are programmed to display human-like social behaviour to increase intuitiveness of interacting with these agents. It is not yet clear to what extent people respond to agents’ social behaviours. One example is touch. Despite robots’ embodiment and increasing autonomy, the effect of communicative touch has been a mostly overlooked aspect of human-robot interaction. This video-based, 2x2 betweensubject survey experiment (N=119) found that the combination of touch and proactivity influenced whether people saw the robot as machine-like and dependable. Participants’ attitude towards robots in general also influenced perceived closeness between humans and robots. Results show that communicative touch is considered a more appropriate behaviour for proactive agents rather than reactive agents. Also, people that are generally more positive towards robots find robots that interact by touch less machine-like. These effects illustrate that careful consideration is necessary when incorporating social behaviours in agents’ physical interaction design.

State of the art web search applications allow the user to aggregate information from many sources. Because of this, users are confronted with having to assess the reliability of information from different sources. This paper reports on an empirical user study on the effect of displaying credibility ratings of multiple cultural heritage sources (e.g. museum websites, art blogs) on users' search performance and selection. The study investigated whether source credibility has an influence on users' search performance when they are confronted with only a few information sources or where there are many. The results of our online interactive study (n=122) show that by presenting the source credibility information explicitly, people's confidence in their selection of information significantly increases, even though it does not necessarily make search more time efficient. Additionally, we highlight credibility issues that are applicable beyond the cultural heritage domain, such as issues related to credibility measures and choice of visualization.

We describe two user studies that investigate organization strategies of autocompletion in a known-item search task: searching for terms taken from a thesaurus. In Study 1, we explored ways of grouping term suggestions from two different thesauri (TGN and WordNet) and found that different thesauri may require different organization strategies. Users found Group organization more appropriate for location names from TGN, while Alphabetical works better for object names from WordNet. In Study 2, we compared three different organization strategies (Alphabetical, Group and Composite) for location name search tasks. The results indicate that for TGN autocompletion interfaces help improve the quality of keywords, Group and Composite organization help users search faster, and is perceived easier to understand and to use than Alphabetical.

Despite robots' embodiment, the effect of physical contact or touch and its interaction with robots' autonomous behaviour has been a mostly overlooked aspect of human-robot interaction. This video-based, 2x2 between-subject survey experiment (N=119) found that touch and proactiveness interacted in their effects on perceived machine-likeness and dependability. Attitude towards robots in general also interacted with the effects of touch. Results show the value of further exploring the combination of physical aspects of human-robot interaction and proactiveness.

The Web of data enables fragments of information to be identified, described and connected together in a rich information environment. Users requiring information are faced with the problem of finding out what information is available, and obtaining sufficient fragments to successfully carry out their task. Systems supporting these tasks can use the fragments, descriptions of them and relationships among them, to improve both the selection and presentation of the information. Questions to be answered are: which information needs can be better supported, and how can the Web of data help. While the construction of the linked data cloud'' is necessary to even start thinking about providing this type of support for users, our claim is that we first need to establish the user's information needs before establishing the potential roles the linked data can play in information selection and presentation. In this paper, we discuss potential uses of linked data to support users' information needs, give examples of using linked data to support user information seeking tasks and highlight future research directions.

In this article we describe a Semantic Web application for semantic annotation and search in large virtual collections of cultural-heritage objects, indexed with multiple vocabularies. During the annotation phase we harvest, enrich and align collection metadata and vocabularies. The semantic-search facilities support keyword-based queries of the graph (currently 20 M triples), resulting in semantically grouped result clusters, all representing potential semantic matches of the original query. We show two sample search scenario’s. The annotation and search software is open source and is already being used by third parties. All software is based on established Web standards, in particular HTML/XML, CSS, RDF/OWL, SPARQL and JavaScript.