Maarten de Rijke

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Maarten de Rijke is an author.


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Title Keyword(s) Published in Language DateThis property is a special property in this wiki. Abstract R C
The impact of semantic document expansion on cluster-based fusion for microblog search Lecture Notes in Computer Science English 2014 Searching microblog posts, with their limited length and creative language usage, is challenging. We frame the microblog search problem as a data fusion problem. We examine the effectiveness of a recent cluster-based fusion method on the task of retrieving microblog posts. We find that in the optimal setting the contribution of the clustering information is very limited, which we hypothesize to be due to the limited length of microblog posts. To increase the contribution of the clustering information in cluster-based fusion, we integrate semantic document expansion as a preprocessing step. We enrich the content of microblog posts appearing in the lists to be fused by Wikipedia articles, based on which clusters are created. We verify the effectiveness of our combined document expansion plus fusion method by making comparisons with microblog search algorithms and other fusion methods. 0 0
Adding semantics to microblog posts Algorithms
WSDM 2012 - Proceedings of the 5th ACM International Conference on Web Search and Data Mining English 2012 Microblogs have become an important source of information for the purpose of marketing, intelligence, and reputation management. Streams of microblogs are of great value because of their direct and real-time nature. Determining what an individual microblog post is about, however, can be non-trivial because of creative language usage, the highly contextualized and informal nature of microblog posts, and the limited length of this form of communication. We propose a solution to the problem of determining what a microblog post is about through semantic linking: we add semantics to posts by automatically identifying concepts that are semantically related to it and generating links to the corresponding Wikipedia articles. The identified concepts can subsequently be used for, e.g., social media mining, thereby reducing the need for manual inspection and selection. Using a purpose-built test collection of tweets, we show that recently proposed approaches for semantic linking do not perform well, mainly due to the idiosyncratic nature of microblog posts. We propose a novel method based on machine learning with a set of innovative features and show that it is able to achieve significant improvements over all other methods, especially in terms of precision. Copyright 2012 ACM. 0 0
Exploiting external collections for query expansion Blog post retrieval
External expansion
Query modeling
ACM Transactions on the Web English 2012 A persisting challenge in the field of information retrieval is the vocabulary mismatch between a user's information need and the relevant documents. One way of addressing this issue is to apply query modeling: to add terms to the original query and reweigh the terms. In social media, where documents usually contain creative and noisy language (e.g., spelling and grammatical errors), query modeling proves difficult. To address this, attempts to use external sources for query modeling have been made and seem to be successful. In this article we propose a general generative query expansion model that uses external document collections for term generation: the External Expansion Model (EEM). The main rationale behind our model is our hypothesis that each query requires its own mixture of external collections for expansion and that an expansion model should account for this. For some queries we expect, for example, a news collection to be most beneficial, while for other queries we could benefit more by selecting terms from a general encyclopedia. EEM allows for query-dependent weighing of the external collections. We put our model to the test on the task of blog post retrieval and we use four external collections in our experiments: (i) a news collection, (ii) a Web collection, (iii) Wikipedia, and (iv) a blog post collection. Experiments show that EEM outperforms query expansion on the individual collections, as well as the Mixture of Relevance Models that was previously proposed by Diaz and Metzler [2006]. Extensive analysis of the results shows that our naive approach to estimating query-dependent collection importance works reasonably well and that, when we use "oracle" settings, we see the full potential of our model. We also find that the query-dependent collection importance has more impact on retrieval performance than the independent collection importance (i.e., a collection prior). 0 0
Generating links to background knowledge: A case study using narrative radiology reports Automatic link generation
Radiology reports
International Conference on Information and Knowledge Management, Proceedings English 2011 Automatically annotating texts with background information has recently received much attention. We conduct a case study in automatically generating links from narrative radiology reports to Wikipedia. Such links help users understand the medical terminology and thereby increase the value of the reports. Direct applications of existing automatic link generation systems trained on Wikipedia to our radiology data do not yield satisfactory results. Our analysis reveals that medical phrases are often syntactically regular but semantically complicated, e.g., containing multiple concepts or concepts with multiple modifiers. The latter property is the main reason for the failure of existing systems. Based on this observation, we propose an automatic link generation approach that takes into account these properties. We use a sequential labeling approach with syntactic features for anchor text identification in order to exploit syntactic regularities in medical terminology. We combine this with a sub-anchor based approach to target finding, which is aimed at coping with the complex semantic structure of medical phrases. Empirical results show that the proposed system effectively improves the performance over existing systems. 0 0
Linking online news and social media Linking
Online news
Social media
User generated content
Proceedings of the 4th ACM International Conference on Web Search and Data Mining, WSDM 2011 English 2011 Much of what is discussed in social media is inspired by events in the news and, vice versa, social media provide us with a handle on the impact of news events. We address the following linking task: given a news article, find social media utterances that implicitly reference it. We follow a three-step approach: we derive multiple query models from a given source news article, which are then used to retrieve utterances from a target social media index, resulting in multiple ranked lists that we then merge using data fusion techniques. Query models are created by exploiting the structure of the source article and by using explicitly linked social media utterances that discuss the source article. To combat query drift resulting from the large volume of text, either in the source news article itself or in social media utterances explicitly linked to it, we introduce a graph-based method for selecting discriminative terms. For our experimental evaluation, we use data from Twitter, Digg, Delicious, the New York Times Community, Wikipedia, and the blogosphere to generate query models. We show that different query models, based on different data sources, provide complementary information and manage to retrieve different social media utterances from our target index. As a consequence, data fusion methods manage to significantly boost retrieval performance over individual approaches. Our graph-based term selection method is shown to help improve both effectiveness and efficiency. Copyright 2011 ACM. 0 0
A ranking approach to target detection for automatic link generation Disambiguation
Learning to rank
Link generation
SIGIR 2010 Proceedings - 33rd Annual International ACM SIGIR Conference on Research and Development in Information Retrieval English 2010 We focus on the task of target detection in automatic link generation with Wikipedia, i.e., given an N-gram in a snippet of text, find the relevant Wikipedia concepts that explain or provide background knowledge for it. We formulate the task as a ranking problem and investigate the effectiveness of learning to rank approaches and of the features that we use to rank the target concepts for a given N-gram. Our experiments show that learning to rank approaches outperform traditional binary classification approaches. Also, our proposed features are effective both in binary classification and learning to rank settings. 0 0
An exploration of learning to link with wikipedia: Features, methods and training collection Lecture Notes in Computer Science English 2010 We describe our participation in the Link-the-Wiki track at INEX 2009. We apply machine learning methods to the anchor-to-best-entry-point task and explore the impact of the following aspects of our approaches: features, learning methods as well as the collection used for training the models. We find that a learning to rank-based approach and a binary classification approach do not differ a lot. The new Wikipedia collection which is of larger size and which has more links than the collection previously used, provides better training material for learning our models. In addition, a heuristic run which combines the two intuitively most useful features outperforms machine learning based runs, which suggests that a further analysis and selection of features is necessary. 0 0
Ranking related entities: Components and analyses Entity search
Language modeling
International Conference on Information and Knowledge Management, Proceedings English 2010 Related entity finding is the task of returning a ranked list of homepages of relevant entities of a specified type that need to engage in a given relationship with a given source entity. We propose a framework for addressing this task and perform a detailed analysis of four core components; co-occurrence models, type filtering, context modeling and homepage finding. Our initial focus is on recall. We analyze the performance of a model that only uses cooccurrence statistics. While it identifies a set of related entities, it fails to rank them effectively. Two types of error emerge: (1) entities of the wrong type pollute the ranking and (2) while somehow associated to the source entity, some retrieved entities do not engage in the right relation with it. To address (1), we add type filtering based on category information available in Wikipedia. To correct for (2), we add contextual information, represented as language models derived from documents in which source and target entities co-occur. To complete the pipeline, we find homepages of top ranked entities by combining a language modeling approach with heuristics based on Wikipedia's external links. Our method achieves very high recall scores on the end-to-end task, providing a solid starting point for expanding our focus to improve precision; additional heuristics lead to state-of-the-art performance. 0 0
Supervised query modeling using Wikipedia English 2010 We use Wikipedia articles to semantically inform the generation of query models. To this end, we apply supervised machine learning to automatically link queries to Wikipedia articles and sample terms from the linked articles to re-estimate the query model. On a recent large web corpus, we observe substantial gains in terms of both traditional metrics and diversity measures. 0 0
Related Entity Finding based on co-occurrence NIST Special Publication English 2009 We report on experiments for the Related Entity Finding task in which we focus on only using Wikipedia as a target corpus in which to identify (related) entitities. Our approach is based on co-occurrences between the source entity and potential target entities. We observe improvements in performance when a context-independent co-occurrence model is combined with context-dependent co-occurrence models in which we stress the importance of the expected relation between source and target entity. Applying type filtering yields further improvements results. 0 0
External query expansion in the blogosphere NIST Special Publication English 2008 We describe the participation of the University of Amsterdam's ILPS group in the blog track at TREC 2008. We mainly explored different ways of using external corpora to expand the original query. In the blog post retrieval task we did not succeed in improving over a simple baseline (equal weights for both the expanded and original query). Obtaining optimal weights for the original and the expanded query remains a subject of investigation. In the blog distillation task we tried to improve over our (strong) baseline using external expansion, but due to differences in the run setup, comparing these runs is hard. Compared to a simpler baseline, we see an improvement for the run using external expansion on the combination of news, Wikipedia and blog posts. 0 0
Named entity normalization in user generated content Named entities
User generated content
Proceedings of SIGIR 2008 Workshop on Analytics for Noisy Unstructured Text Data, AND'08 English 2008 Named entity recognition is important for semantically oriented retrieval tasks, such as question answering, entity retrieval, biomedical retrieval, trend detection, and event and entity tracking. In many of these tasks it is important to be able to accurately normalize the recognized entities, i.e., to map surface forms to unambiguous references to real world entities. Within the context of structured databases, this task (known as record linkage and data, de-duplication) has been a topic of active research for more than five decades. For edited content, such as news articles, the named entity normalization (NEN) task is one that has recently attracted considerable attention. We consider the task in the challenging context of user generated content (UGC), where it forms a key ingredient of tracking and media-analysis systems. A baseline NEN system from the literature (that normalizes surface forms to Wikipedia pages) performs considerably worse on UGC than on edited news: accuracy drops from 80% to 65% for a Dutch language data set and from 94% to 77% for English. We identify several sources of errors: entity recognition errors, multiple ways of referring to the same entity and ambiguous references. To address these issues we propose five improvements to the baseline NEN algorithm, to arrive at a language independent NEN system that achieves overall accuracy scores of 90% on the English data set and 89% on the Dutch data set. We show that each of the improvements contributes to the overall score of our improved NEN algorithm, and conclude with an error analysis on both Dutch and English language UGC. The NEN system is computationally efficient and runs with very modest computational requirements. Copyright 2008 ACM. 0 0
The university of amsterdam's question answering system at QA@CLEF 2007 Lecture Notes in Computer Science English 2008 We describe a new version of our question answering system, which was applied to the questions of the 2007 CLEF Question Answering Dutch monolingual task. This year, we made three major modifications to the system: (1) we added the contents of Wikipedia to the document collection and the answer tables; (2) we completely rewrote the module interface code in Java; and (3) we included a new table stream which returned answer candidates based on information which was learned from question-answer pairs. Unfortunately, the changes did not lead to improved performance. Unsolved technical problems at the time of the deadline have led to missing justifications for a large number of answers in our submission. Our single run obtained an accuracy of only 8% with an additional 12% of unsupported answers (compared to 21% in the last year's task). 0 0
"More like these": Growing entity classes from seeds Lexical acquisition
List expansion
International Conference on Information and Knowledge Management, Proceedings English 2007 We present a corpus-based approach to the class expansion task. For a given set of seed entities we use co-occurrence statistics taken from a text collection to define a membership function that is used to rank candidate entities for inclusion in the set. We describe an evaluation framework that uses data from Wikipedia. The performance of our class extension method improves as the size of the text collection increases. Copyright 2007 ACM. 0 0
Fact Discovery in Wikipedia English 2007 0 0
Fact discovery in Wikipedia Proceedings of the IEEE/WIC/ACM International Conference on Web Intelligence, WI 2007 English 2007 We address the task of extracting focused salient information items, relevant and important for a given topic, from a large encyclopedic resource. Specifically, for a given topic (a Wikipedia article) we identify snippets from other articles in Wikipedia that contain important information for the topic of the original article, without duplicates. We compare several methods for addressing the task, and find that a mixture of content-based, link-based, and layout-based features outperforms other methods, especially in combination with the use of so-called reference corpora that capture the key properties of entities of a common type. 0 0
Link-based vs. content-based retrieval for question answering using Wikipedia Lecture Notes in Computer Science English 2007 We describe our participation in the WiQA 2006 pilot on question answering using Wikipedia, with a focus on comparing linkbased vs content-based retrieval. Our system currently works for Dutch and English. 0 0
Finding Similar Sentences across Multiple Languages in Wikipedia English 2006 0 3
Discovering missing links in Wikipedia English 2005 In this paper we address the problem of discovering missing hypertext links in Wikipedia. The method we propose consists of two steps: first, we compute a cluster of highly similar pages around a given page, and then we identify candidate links from those similar pages that might be missing on the given page. The main innovation is in the algorithm that we use for identifying similar pages, LTRank, which ranks pages using co-citation and page title information. Both LTRank and the link discovery method are manually evaluated and show acceptable results, especially given the simplicity of the methods and conservativeness of the evaluation criteria. 0 1