The large number of potential applications from bridging web data with knowledge bases have led to an increase in the entity linking research. Entity linking is the task to link entity mentions in text with their corresponding entities in a knowledge base. Potential applications include information extraction, information retrieval, and knowledge base population. However, this task is challenging due to name variations and entity ambiguity. In this survey, we present a thorough overview and analysis of the main approaches to entity linking, and discuss various applications, the evaluation of entity linking systems, and future directions.

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Entity Linking with a Knowledge Base: Issues, Techniques, and Solutions

http://benhachey.info/pubs/hachey-aij12-evaluating.pdf

Evaluating Entity Linking with Wikipedia

Artificial intelligence (AI) has transformed the world and the relationships among humans as the learning capabilities of machines have allowed for a new means of communication between humans and machines. In the field of health, there is much interest in new technologies that help to improve and automate services in hospitals. This article aims to explore the literature related to conversational agents applied to health care, searching for definitions, patterns, methods, architectures, and data types. Furthermore, this work identifies an agent application taxonomy, current challenges, and research gaps. In this work, we use a systematic literature review approach. We guide and refine this study and the research questions by applying Population, Intervention, Comparison, Outcome, and Context (PICOC) criteria. The present study investigated approximately 4145 articles involving conversational agents in health published over the last ten years. In this context, we finally selected 40 articles based on their approaches and objectives as related to our main subject. As a result, we developed a taxonomy, identified the main challenges in the field, and defined the main types of dialog and contexts related to conversational agents in health. These results contributed to discussions regarding conversational health agents, and highlighted some research gaps for future study.

Survey of conversational agents in health

Entity linking refers entity mentions in a document to their representations in a knowledge base (KB). In this paper, we propose to use additional information sources from Wikipedia to find more name variations for entity linking task. In addition, as manually creating a training corpus for entity linking is laborintensive and costly, we present a novel method to automatically generate a large scale corpus annotation for ambiguous mentions leveraging on their unambiguous synonyms in the document collection. Then, a binary classifier is trained to filter out KB entities that are not similar to current mentions. This classifier not only can effectively reduce the ambiguities to the existing entities in KB, but also be very useful to highlight the new entities to KB for the further population. Furthermore, we also leverage on the Wikipedia documents to provide additional information which is not available in our generated corpus through a domain adaption approach which provides further performance improvements. The experiment results show that our proposed method outperforms the state-of-the-art approaches.

Entity Linking Leveraging Automatically Generated Annotation

This paper describes the first round of ResPubliQA, a Question Answering (QA) evaluation task over European legislation, proposed at the Cross Language Evaluation Forum (CLEF) 2009. The exercise consists of extracting a relevant paragraph of text that satisfies completely the information need expressed by a natural language question. The general goals of this exercise are (i) to study if the current QA technologies tuned for newswire collections and Wikipedia can be adapted to a new domain (law in this case); (ii) to move to a more realistic scenario, considering people close to law as users, and paragraphs as system output; (iii) to compare current QA technologies with pure Information Retrieval (IR) approaches; and (iv) to introduce in QA systems the Answer Validation technologies developed in the past three years. The paper describes the task in more detail, presenting the different types of questions, the methodology for the creation of the test sets and the new evaluation measure, and analyzing the results obtained by systems and the more successful approaches. Eleven groups participated with 28 runs. In addition, we evaluated 16 baseline runs (2 per language) based only in pure IR approach, for comparison purposes. Considering accuracy, scores were generally higher than in previous QA campaigns.

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Overview of ResPubliQA 2009: question answering evaluation over European legislation

This paper describes our participation at TAC 2008 in all the three tracks. For the Summarization Track we introduced two major features. First, a feature based on Information Loss if we don’t pick a particular sentence. Second, a language modeling extension that boosts novel terms and penalizes stale terms. During our post-TAC analysis we observed that a simple sentence position based summarizer leads to better short summaries than most official runs submitted this year. In the Opinion QA and Summarization Track for the rigid list questions, we have added some additional features to handle opinion expressed in the question. and for the squishy list questions in Opinion QA and Summarization Track, we leveraged on our existing Summarization engine and used a classification based approach to both finding opinionated sentences and also the polarity of the opinions. Finally, for the RTE track we explored a simple graph partition matching based approach.

/pdf/iiit-hyderabad-at-tac-2008-1p0oahjr9d.pdf

IIIT Hyderabad at TAC 2008

In this paper we present a statistical transliteration technique that is language independent. This technique uses Hidden Markov Model (HMM) alignment and Conditional Random Fields (CRF), a discriminative model. HMM alignment maximizes the probability of the observed (source, target) word pairs using the expectation maximization algorithm and then the character level alignments (n-gram) are set to maximum posterior predictions of the model. CRF has efficient training and decoding processes which is conditioned on both source and target languages and produces globally optimal solutions. We apply this technique for Hindi-English transliteration task. The results show that our technique perfoms better than the existing transliteration system which uses HMM alignment and conditional probabilities derived from counting the alignments.

/pdf/statistical-transliteration-for-cross-langauge-information-2l1osx77sh.pdf

Statistical Transliteration for Cross Langauge Information Retrieval using HMM alignment and CRF

In this paper we present a statistical transliteration technique that is language independent. This technique uses statistical alignment models and Conditional Random Fields (CRF). Statistical alignment models maximizes the probability of the observed (source, target) word pairs using the expectation maximization algorithm and then the character level alignments are set to maximum posterior predictions of the model. CRF has efficient training and decoding processes which is conditioned on both source and target languages and produces globally optimal solution.

/pdf/a-language-independent-transliteration-schema-using-1u7q8zaew3.pdf

A Language-Independent Transliteration Schema Using Character Aligned Models at NEWS 2009

Exploiting Structure and Content of Wikipedia for Query Expansion in the Context

Retrieving answer containing passages is a challenging task in Question Answering. In this paper we describe a novel query expansion method which aims to rank the answer containing passages better. It uses content and structured information (link structure and category information) of Wikipedia to generate a set of terms semantically related to the question. As Boolean model allows a fine-grained control over query expansion, these semantically related terms are added to the original query to form an expanded Boolean query. We conducted experiments on TREC 2006 QA data. The experimental results show significant improvements of about 24.6%, 11.1% and 12.4% in precision at 1, MRR at 20 and TDRR scores respectively using our query expansion method.

Surya Ganesh

Papers

IIIT Hyderabad at TAC 2008

Statistical Transliteration for Cross Langauge Information Retrieval using HMM alignment and CRF

A Language-Independent Transliteration Schema Using Character Aligned Models at NEWS 2009

Exploiting Structure and Content of Wikipedia for Query Expansion in the Context

Exploiting structure and content of Wikipedia for Query Expansion in the context of Question Answering