People with complex information needs are for example Humanities researchers, who need advanced search engines to investigate their research questions. Much can be gained by combining research datasets, reusing tools and serendipitously discovering new insights for further research. Humanities researchers have di erent (large-scale) research datasets and tools, which are described di erently with metadata. We present a highly interactive advanced search engine for Humanities researchers that semantically converges di erently structured metadata records from di erent collections and institutions. It has features that support serendipitous and focused search in context based on the structure of the metadata used. This single system serves Humanities researchers by allowing them to search interactively across yet unexplored (research) data, discover patterns, locate relevant data for new insights, and nd existing tools that could provide novel use cases. H.3.3 [Information Search and Retrieval]: Search process; H.3.7 [Digital Libraries]: Systems issues, user issues; H.5.2 [Information interfaces and presentation]: Graphical user interfaces (GUI) General Terms
The Common Language Resources and Technology
Infrastructure (CLARIN) initiative seeks to establish an
integrated and interoperable research infrastructure of language
Presented at EuroHCIR2012. Copyright c 2012 for the individual papers
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resources and its technology.1 Descriptive metadata is used
to characterize large number of (legacy) research data
resources (collections) and tools (e.g. Web services) to
facilitate their management and discovery. The Search & Develop
(S&D) project within CLARIN in the Netherlands uses the
Component MetaData Infrastructure (CMDI; [
How to use the CMDI framework with ISOcat to search
for data and services, which can be understood by both
people from varying disciplines and machines? The challenge is
that the data is heterogenous both in content and
structure, and can be massive in amount. In [
CMDI has grown out of the need to facilitate access,
reuse, and interoperability using metadata [
The DCR was established by the ISO Technical Committee 37, Terminology and other language and content resources based on the ISO 12620:2009 standard. Because multiple elements may refer to the same DC, semantic interoperability can be achieved across di erent datasets. A speci cation using the DCR and projected for example in an XML schema is called a metadata pro le and can be (re)used for describ1See http://www.clarin.eu/external/index.php?page=aboutclarin (a) Query autocompletion based on the count that a query (b) The selection widget that allows users to keep overview of occurs in a tag within the result set. By default the query box the search trail and change it, while updating the result list. is content-centric, but searching directly in a tag is possible Here, the query stored is \periode" (period) within the tag with Advanced Search (can be collapsed with a click). Users time coverage!description. Interesting terms are suggested can express queries using the metadata or only the fulltext by presenting the top TF IDF terms, which people can use of the document by discarding autocompletion. to start a parallel search episode. (c) To further support query expansion and serendipitous in- (d) The distribution of retrieved time-referenced documents formation seeking, a dynamic tag cloud is generated based (given the tags Century of Publication and Year of Publicaon the last retrieved result list and used metadata label with tion) are visualized in bar or line charts. Users can click in keyword highlighting. Moreover, retrieved geo-referenced the charts to narrow down the result set. The distribution of documents are projected on a map and clustered by markers. results in tags collection and schema pro le always appear. (a) Retrieved list of results with the display of the list of results with ` xed' contextual information, snippets and keywords in context within the last searched metadata label and the presentation of all used keywords in context given the fulltext. There is links to the fulltext of the metadata record and the actual resource in the digital archive. (b) For each retrieved result in the list, there is a recommendation (when available) of related results based on the content similarity of the last used metadata label. A recommendation consist of a link to the record, the collection it belongs to, and a snippet (can be collapsed with a click).
ing datasets and for eventual access. Moreover, RELcat [
We have indexed 246,728 CMDI les from 18 di erent
proles consisting of 143 di erent types of elements in a single
stream, which shows our indexing method for CMDI les is
robust enough to deal with complex data [
When a user with no a priori intentions interacts with a
node of information and acquires useful information, then
serendipitous information retrieval occurs [
Since the CMDI MI Search Engine should serve
Humanities researchers, we design it to support serendipitous search
and be highly interactive. The system has been designed to
maximize the user's ability to explore. This is our focus.
The user interface of the system is depicted in Fig 1. It uses
the JavaScript library AJAX Solr2, which has been
heavily modi ed and extended by us with JQuery. It allows for
faceted search [
A user can improving the search episode (session) by effectively reducing the information space step by step. These steps are stored as part of the search trail, so the overview is kept. There are di erent search strategies possible. Users can search by fulltext by entering a query. This makes sure users can always search in everything. The query get highlighted in context given the fulltext, but the dynamic tag cloud widget that supports query expansion is not activated, see Fig.1(a). Users can also do a focused search request by using structure, i.e. within the content of a speci ed tag, and get the content of these tags returned. This can be content-centered, as users enter a keyword and the autocompletion widget returns a list consisting of keyword plus eld name and hit count. It can also be structure-centered (using the Advanced Search option) by looking up a tag and then entering a keyword also with the autocompletion feature. When the last two options are used, then the keyword highlighting also occurs within the context of the retrieved 2See https://github.com/evolvingweb/ajax-solr snippets of the searched tag, see Fig.2(a).
A challenge is how we can support serendipitous search given the diversely structured metadata in CMDI. Hence, we introduce and propose the concept of serendipitous search in context. We can use the heterogeneous structure of di erent collections to provide context to the user in a single search engine. We propose the following contextual system features that aim to support serendipitous and focused search.
look for...) by presenting interesting terms based on the content of the rst few retrieved results after each used query, see Fig.1(b). This increments and becomes more focused as a search episode gets more queries.
allow for query expansion by directly presenting a dynamic tag cloud of the aggregated content within the metadata label used and highlighting the query entered in this context, see Fig.1(c).
the search selection (see Fig.1(b)), and the overview on collection level by the result type, e.g. the metadata pro le `lied' (song) in the Dutch Song Database, and the collection a document belongs to (see Fig.1(d)).
tures in extra widgets, such as projecting and clustering the list of retrieved geo-referenced resources on a map (see Fig. 1(c)), and displaying the date ranges of the documents in charts that can be clicked to narrow down a result set (see Fig. 1(d)).
So the context consists of di erent modalities and features existing in the structure of the metadata of a collection, and used in the retrieval and visualization of information. This can be displayed on a aggregated level based on the set of retrieved results. And it can be displayed with di erent displays of the result types given the metadata pro le. Eventually, the user nds the links to the resources in the digital archive using the metadata, and can use the found resources for further research or development. However, there is no real de nite end of the search episode as people still can continue searching using the above proposed system features.
We have presented a working proposition for serendipitous and focused search by describing the CMDI MI search engine. The novelty is that it provides semantic access to diversely structured language and digital heritage resources with di erent metadata schemas for users such as researchers with very speci c and complex information (research) needs. The search engine provides faceted search and has serendipitous features that maximize the user's ability to explore any metadata in CMDI in context, such as query autocompletion, tag clouds, and recommendation of related resources, while keeping track of the search trail. It is a tool that provides interactive and focused access to heterogeneous metadata, gives new perspectives on legacy (research) data and tools, and provides new insights for research and development. It has been released as live, and can be used at www.meertens.knaw.nl/cmdi/search. 5.
This work is part of the Search & Develop project at the Meertens Institute, and funded by CLARIN-NL.