8,843 research outputs found
Parsimonious Language Models for a Terabyte of Text
The aims of this paper are twofold. Our first aim\ud
is to compare results of the earlier Terabyte tracks\ud
to the Million Query track. We submitted a number\ud
of runs using different document representations\ud
(such as full-text, title-fields, or incoming\ud
anchor-texts) to increase pool diversity. The initial\ud
results show broad agreement in system rankings\ud
over various measures on topic sets judged at both\ud
Terabyte and Million Query tracks, with runs using\ud
the full-text index giving superior results on\ud
all measures, but also some noteworthy upsets.\ud
Our second aim is to explore the use of parsimonious\ud
language models for retrieval on terabyte-scale\ud
collections. These models are smaller thus\ud
more efficient than the standard language models\ud
when used at indexing time, and they may also improve\ud
retrieval performance. We have conducted\ud
initial experiments using parsimonious models in\ud
combination with pseudo-relevance feedback, for\ud
both the Terabyte and Million Query track topic\ud
sets, and obtained promising initial results
Query Chains: Learning to Rank from Implicit Feedback
This paper presents a novel approach for using clickthrough data to learn
ranked retrieval functions for web search results. We observe that users
searching the web often perform a sequence, or chain, of queries with a similar
information need. Using query chains, we generate new types of preference
judgments from search engine logs, thus taking advantage of user intelligence
in reformulating queries. To validate our method we perform a controlled user
study comparing generated preference judgments to explicit relevance judgments.
We also implemented a real-world search engine to test our approach, using a
modified ranking SVM to learn an improved ranking function from preference
data. Our results demonstrate significant improvements in the ranking given by
the search engine. The learned rankings outperform both a static ranking
function, as well as one trained without considering query chains.Comment: 10 page
New perspectives on Web search engine research
Purpose–The purpose of this chapter is to give an overview of the context of Web search and search engine-related research, as well as to introduce the reader to the sections and chapters of the book. Methodology/approach–We review literature dealing with various aspects of search engines, with special emphasis on emerging areas of Web searching, search engine evaluation going beyond traditional methods, and new perspectives on Webs earching. Findings–The approaches to studying Web search engines are manifold. Given the importance of Web search engines for knowledge acquisition, research from different perspectives needs to be integrated into a more cohesive perspective. Researchlimitations/implications–The chapter suggests a basis for research in the field and also introduces further research directions. Originality/valueofpaper–The chapter gives a concise overview of the topics dealt with in the book and also shows directions for researchers interested in Web search engines
An Axiomatic Analysis of Diversity Evaluation Metrics: Introducing the Rank-Biased Utility Metric
Many evaluation metrics have been defined to evaluate the effectiveness
ad-hoc retrieval and search result diversification systems. However, it is
often unclear which evaluation metric should be used to analyze the performance
of retrieval systems given a specific task. Axiomatic analysis is an
informative mechanism to understand the fundamentals of metrics and their
suitability for particular scenarios. In this paper, we define a
constraint-based axiomatic framework to study the suitability of existing
metrics in search result diversification scenarios. The analysis informed the
definition of Rank-Biased Utility (RBU) -- an adaptation of the well-known
Rank-Biased Precision metric -- that takes into account redundancy and the user
effort associated to the inspection of documents in the ranking. Our
experiments over standard diversity evaluation campaigns show that the proposed
metric captures quality criteria reflected by different metrics, being suitable
in the absence of knowledge about particular features of the scenario under
study.Comment: Original version: 10 pages. Preprint of full paper to appear at
SIGIR'18: The 41st International ACM SIGIR Conference on Research &
Development in Information Retrieval, July 8-12, 2018, Ann Arbor, MI, USA.
ACM, New York, NY, US
Social Search with Missing Data: Which Ranking Algorithm?
Online social networking tools are extremely popular, but can miss potential discoveries latent in the social 'fabric'. Matchmaking services which can do naive profile matching with old database technology are too brittle in the absence of key data, and even modern ontological markup, though powerful, can be onerous at data-input time. In this paper, we present a system called BuddyFinder which can automatically identify buddies who can best match a user's search requirements specified in a term-based query, even in the absence of stored user-profiles. We deploy and compare five statistical measures, namely, our own CORDER, mutual information (MI), phi-squared, improved MI and Z score, and two TF/IDF based baseline methods to find online users who best match the search requirements based on 'inferred profiles' of these users in the form of scavenged web pages. These measures identify statistically significant relationships between online users and a term-based query. Our user evaluation on two groups of users shows that BuddyFinder can find users highly relevant to search queries, and that CORDER achieved the best average ranking correlations among all seven algorithms and improved the performance of both baseline methods
Relation Discovery from Web Data for Competency Management
This paper describes a technique for automatically discovering associations between people and expertise from an analysis of very large data sources (including web pages, blogs and emails), using a family of algorithms that perform accurate named-entity recognition, assign different weights to terms according to an analysis of document structure, and access distances between terms in a document. My contribution is to add a social networking approach called BuddyFinder which relies on associations within a large enterprise-wide "buddy list" to help delimit the search space and also to provide a form of 'social triangulation' whereby the system can discover documents from your colleagues that contain pertinent information about you. This work has been influential in the information retrieval community generally, as it is the basis of a landmark system that achieved overall first place in every category in the Enterprise Search Track of TREC2006
PACRR: A Position-Aware Neural IR Model for Relevance Matching
In order to adopt deep learning for information retrieval, models are needed
that can capture all relevant information required to assess the relevance of a
document to a given user query. While previous works have successfully captured
unigram term matches, how to fully employ position-dependent information such
as proximity and term dependencies has been insufficiently explored. In this
work, we propose a novel neural IR model named PACRR aiming at better modeling
position-dependent interactions between a query and a document. Extensive
experiments on six years' TREC Web Track data confirm that the proposed model
yields better results under multiple benchmarks.Comment: To appear in EMNLP201
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