1,747 research outputs found
Simplifying Deep-Learning-Based Model for Code Search
To accelerate software development, developers frequently search and reuse
existing code snippets from a large-scale codebase, e.g., GitHub. Over the
years, researchers proposed many information retrieval (IR) based models for
code search, which match keywords in query with code text. But they fail to
connect the semantic gap between query and code. To conquer this challenge, Gu
et al. proposed a deep-learning-based model named DeepCS. It jointly embeds
method code and natural language description into a shared vector space, where
methods related to a natural language query are retrieved according to their
vector similarities. However, DeepCS' working process is complicated and
time-consuming. To overcome this issue, we proposed a simplified model
CodeMatcher that leverages the IR technique but maintains many features in
DeepCS. Generally, CodeMatcher combines query keywords with the original order,
performs a fuzzy search on name and body strings of methods, and returned the
best-matched methods with the longer sequence of used keywords. We verified its
effectiveness on a large-scale codebase with about 41k repositories.
Experimental results showed the simplified model CodeMatcher outperforms DeepCS
by 97% in terms of MRR (a widely used accuracy measure for code search), and it
is over 66 times faster than DeepCS. Besides, comparing with the
state-of-the-art IR-based model CodeHow, CodeMatcher also improves the MRR by
73%. We also observed that: fusing the advantages of IR-based and
deep-learning-based models is promising because they compensate with each other
by nature; improving the quality of method naming helps code search, since
method name plays an important role in connecting query and code
Predicting ConceptNet Path Quality Using Crowdsourced Assessments of Naturalness
In many applications, it is important to characterize the way in which two
concepts are semantically related. Knowledge graphs such as ConceptNet provide
a rich source of information for such characterizations by encoding relations
between concepts as edges in a graph. When two concepts are not directly
connected by an edge, their relationship can still be described in terms of the
paths that connect them. Unfortunately, many of these paths are uninformative
and noisy, which means that the success of applications that use such path
features crucially relies on their ability to select high-quality paths. In
existing applications, this path selection process is based on relatively
simple heuristics. In this paper we instead propose to learn to predict path
quality from crowdsourced human assessments. Since we are interested in a
generic task-independent notion of quality, we simply ask human participants to
rank paths according to their subjective assessment of the paths' naturalness,
without attempting to define naturalness or steering the participants towards
particular indicators of quality. We show that a neural network model trained
on these assessments is able to predict human judgments on unseen paths with
near optimal performance. Most notably, we find that the resulting path
selection method is substantially better than the current heuristic approaches
at identifying meaningful paths.Comment: In Proceedings of the Web Conference (WWW) 201
Concept-based Interactive Query Expansion Support Tool (CIQUEST)
This report describes a three-year project (2000-03) undertaken in the Information Studies
Department at The University of Sheffield and funded by Resource, The Council for
Museums, Archives and Libraries. The overall aim of the research was to provide user
support for query formulation and reformulation in searching large-scale textual resources
including those of the World Wide Web. More specifically the objectives were: to investigate
and evaluate methods for the automatic generation and organisation of concepts derived from
retrieved document sets, based on statistical methods for term weighting; and to conduct
user-based evaluations on the understanding, presentation and retrieval effectiveness of
concept structures in selecting candidate terms for interactive query expansion.
The TREC test collection formed the basis for the seven evaluative experiments conducted in
the course of the project. These formed four distinct phases in the project plan. In the first
phase, a series of experiments was conducted to investigate further techniques for concept
derivation and hierarchical organisation and structure. The second phase was concerned with
user-based validation of the concept structures. Results of phases 1 and 2 informed on the
design of the test system and the user interface was developed in phase 3. The final phase
entailed a user-based summative evaluation of the CiQuest system.
The main findings demonstrate that concept hierarchies can effectively be generated from
sets of retrieved documents and displayed to searchers in a meaningful way. The approach
provides the searcher with an overview of the contents of the retrieved documents, which in
turn facilitates the viewing of documents and selection of the most relevant ones. Concept
hierarchies are a good source of terms for query expansion and can improve precision. The
extraction of descriptive phrases as an alternative source of terms was also effective. With
respect to presentation, cascading menus were easy to browse for selecting terms and for
viewing documents. In conclusion the project dissemination programme and future work are
outlined
No-But-Semantic-Match: Computing Semantically Matched XML Keyword Search Results
Users are rarely familiar with the content of a data source they are
querying, and therefore cannot avoid using keywords that do not exist in the
data source. Traditional systems may respond with an empty result, causing
dissatisfaction, while the data source in effect holds semantically related
content. In this paper we study this no-but-semantic-match problem on XML
keyword search and propose a solution which enables us to present the top-k
semantically related results to the user. Our solution involves two steps: (a)
extracting semantically related candidate queries from the original query and
(b) processing candidate queries and retrieving the top-k semantically related
results. Candidate queries are generated by replacement of non-mapped keywords
with candidate keywords obtained from an ontological knowledge base. Candidate
results are scored using their cohesiveness and their similarity to the
original query. Since the number of queries to process can be large, with each
result having to be analyzed, we propose pruning techniques to retrieve the
top- results efficiently. We develop two query processing algorithms based
on our pruning techniques. Further, we exploit a property of the candidate
queries to propose a technique for processing multiple queries in batch, which
improves the performance substantially. Extensive experiments on two real
datasets verify the effectiveness and efficiency of the proposed approaches.Comment: 24 pages, 21 figures, 6 tables, submitted to The VLDB Journal for
possible publicatio
Hybrid Query Expansion on Ontology Graph in Biomedical Information Retrieval
Nowadays, biomedical researchers publish thousands of papers and journals every day. Searching through biomedical literature to keep up with the state of the art is a task of increasing difficulty for many individual researchers. The continuously increasing amount of biomedical text data has resulted in high demands for an efficient and effective biomedical information retrieval (BIR) system. Though many existing information retrieval techniques can be directly applied in BIR, BIR distinguishes itself in the extensive use of biomedical terms and abbreviations which present high ambiguity. First of all, we studied a fundamental yet simpler problem of word semantic similarity. We proposed a novel semantic word similarity algorithm and related tools called Weighted Edge Similarity Tools (WEST). WEST was motivated by our discovery that humans are more sensitive to the semantic difference due to the categorization than that due to the generalization/specification. Unlike most existing methods which model the semantic similarity of words based on either the depth of their Lowest Common Ancestor (LCA) or the traversal distance of between the word pair in WordNet, WEST also considers the joint contribution of the weighted distance between two words and the weighted depth of their LCA in WordNet. Experiments show that weighted edge based word similarity method has achieved 83.5% accuracy to human judgments. Query expansion problem can be viewed as selecting top k words which have the maximum accumulated similarity to a given word set. It has been proved as an effective method in BIR and has been studied for over two decades. However, most of the previous researches focus on only one controlled vocabulary: MeSH. In addition, early studies find that applying ontology won\u27t necessarily improve searching performance. In this dissertation, we propose a novel graph based query expansion approach which is able to take advantage of the global information from multiple controlled vocabularies via building a biomedical ontology graph from selected vocabularies in Metathesaurus. We apply Personalized PageRank algorithm on the ontology graph to rank and identify top terms which are highly relevant to the original user query, yet not presented in that query. Those new terms are reordered by a weighted scheme to prioritize specialized concepts. We multiply a scaling factor to those final selected terms to prevent query drifting and append them to the original query in the search. Experiments show that our approach achieves 17.7% improvement in 11 points average precision and recall value against Lucene\u27s default indexing and searching strategy and by 24.8% better against all the other strategies on average. Furthermore, we observe that expanding with specialized concepts rather than generalized concepts can substantially improve the recall-precision performance. Furthermore, we have successfully applied WEST from the underlying WordNet graph to biomedical ontology graph constructed by multiple controlled vocabularies in Metathesaurus. Experiments indicate that WEST further improve the recall-precision performance. Finally, we have developed a Graph-based Biomedical Search Engine (G-Bean) for retrieving and visualizing information from literature using our proposed query expansion algorithm. G-Bean accepts any medical related user query and processes them with expanded medical query to search for the MEDLINE database
- …