Relevance-based entity selection for ad hoc retrieval

© 2019 Recent developments have shown that entity-based models that rely on information from the knowledge graph can improve document retrieval performance. However, given the non-transitive nature of relatedness between entities on the knowledge graph, the use of semantic relatedness measures can lead to topic drift. To address this issue, we propose a relevance-based model for entity selection based on pseudo-relevance feedback, which is then used to systematically expand the input query leading to improved retrieval performance. We perform our experiments on the widely used TREC Web corpora and empirically show that our proposed approach to entity selection significantly improves ad hoc document retrieval compared to strong baselines. More concretely, the contributions of this work are as follows: (1) We introduce a graphical probability model that captures dependencies between entities within the query and documents. (2) We propose an unsupervised entity selection method based on the graphical model for query entity expansion and then for ad hoc retrieval. (3) We thoroughly evaluate our method and compare it with the state-of-the-art keyword and entity based retrieval methods. We demonstrate that the proposed retrieval model shows improved performance over all the other baselines on ClueWeb09B and ClueWeb12B, two widely used Web corpora, on the NDCG@20, and ERR@20 metrics. We also show that the proposed method is most effective on the difficult queries. In addition, We compare our proposed entity selection with a state-of-the-art entity selection technique within the context of ad hoc retrieval using a basic query expansion method and illustrate that it provides more effective retrieval for all expansion weights and different number of expansion entities

Impact of document representation on neural ad hoc retrieval

© 2018 Association for Computing Machinery. Neural embeddings have been effectively integrated into information retrieval tasks including ad hoc retrieval. One of the benefits of neural embeddings is they allow for the calculation of the similarity between queries and documents through vector similarity calculation methods. While such methods have been effective for document matching, they have an inherent bias towards documents that are sized relatively similarly. Therefore, the difference between the query and document lengths, referred to as the query-document size imbalance problem, becomes an issue when incorporating neural embeddings and their associated similarity calculation models into the ad hoc document retrieval process. In this paper, we propose that document representation methods need to be used to address the size imbalance problem and empirically show their impact on the performance of neural embedding-based ad hoc retrieval. In addition, we explore several types of document representation methods and investigate their impact on the retrieval process. We conduct our experiments on three widely used standard corpora, namely Clueweb09B, Clueweb12B and Robust04 and their associated topics. Summarily, we find that document representation methods are able to effectively address the query-document size imbalance problem and significantly improve the performance of neural ad hoc retrieval. In addition, we find that a document representation method based on a simple term-frequency shows significantly better performance compared to more sophisticated representation methods such as neural composition and aspect-based methods

Towards Domain-Centric Ontology Development and Maintenance Frameworks

In this paper, we attempt to study and investigate ontology development and maintenance frameworks from a domain-centric point of view. By frameworks we mean the structures which have been designed to allow ontology engineers and domain experts to develop and maintain domain ontologies. Such frameworks usually specify particular phases for developing ontologies and provide implemented components for each phase. Our purpose is to analyze the suitability of a framework for developing ontologies which can fulfill the necessities of a specific domain. We have designed a comparison model for analyzing ontological frameworks. Using the model, we inspect how an ontological framework utilizes domain information resources for creating and maintaining ontologies, how much fineness and granularity the designed ontology can reach, and with how much maturity it supports the maintenance and integration capabilities in the development process. 1

The Application of Users' Collective Experience for Crafting Suitable Search Engine Query Recommendations

Search engines have turned into one of the most important services of the Web that are frequently visited by any user. They assist their users in finding appropriate information. Among the many challenging issues in the design of Web search engines that is mostly related to the design of an adaptive interface is recommending suitable query phrases to the end-users. This has two major benefits: firstly the users can more easily interact with the Web search engine and secondly get hints on what is more apt to look for in cases where they may not have any clue. In this paper, we propose a graph based query recommendation algorithm that sequentially recommends query terms to its users. The most important notion behind the design of the algorithm is that the past behavior of previous users of a search engine is mined and a multi-segmented graph is built. Recommendation is made based on the relative similarity of query terms, their frequency and conceptual closeness in the graph

Neural word and entity embeddings for ad hoc retrieval

© 2018 Elsevier Ltd Learning low dimensional dense representations of the vocabularies of a corpus, known as neural embeddings, has gained much attention in the information retrieval community. While there have been several successful attempts at integrating embeddings within the ad hoc document retrieval task, yet, no systematic study has been reported that explores the various aspects of neural embeddings and how they impact retrieval performance. In this paper, we perform a methodical study on how neural embeddings influence the ad hoc document retrieval task. More specifically, we systematically explore the following research questions: (i) do methods solely based on neural embeddings perform competitively with state of the art retrieval methods with and without interpolation? (ii) are there any statistically significant difference between the performance of retrieval models when based on word embeddings compared to when knowledge graph entity embeddings are used? and (iii) is there significant difference between using locally trained neural embeddings compared to when globally trained neural embeddings are used? We examine these three research questions across both hard and all queries. Our study finds that word embeddings do not show competitive performance to any of the baselines. In contrast, entity embeddings show competitive performance to the baselines and when interpolated, outperform the best baselines for both hard and soft queries

The Effect of Modification and Update Propagation on Modular Ontologies

Peer reviewed: YesNRC publication: Ye