25,311 research outputs found
Prime-based method for interactive mining of frequent patterns
Over the past decade, an increasing number of efficient mining algorithms have been proposed to mine the frequent patterns by satisfying a user specified threshold called minimum support (minsup). However, determining an appropriate value for minsup to find proper frequent patterns in different applications is extremely difficult. Since rerunning the mining algorithms from scratch can be very time consuming, researchers have introduced interactive mining to find proper patterns by using the current mining model with various minsup. Thus far, a few efficient interactive mining algorithms have been proposed. However, their runtime do not fulfill the need of short runtime in real time applications especially where data is sparse and proper frequent patterns are mined with very low values of minsup.
As response to the above-mentioned challenges, this study is devoted towards developing an interactive mining method based on prime number and its special characteristic âuniquenessâ by which the content of the relevant data is transformed into a compact layout. At first, a general architecture for interactive mining is proposed consisting of two isolated components: mining model and mining process. Then, the proposed method is developed based on the architecture such that the mining model is constructed once, and it can be frequently mined by various minsup. In the mining model construction, the content of relevant data is captured by a novel tree structure called PC-tree with one database scan and mining materials are consequently formed. The PC-tree is a well-organized tree structure, which is systematically built based on descendant making introduced in this study. Moreover, this study introduces a mining algorithm called PC-miner to mine the mining model frequently with various values of minsup. It grows an effective candidate head set introduced in this study starting from the longest candidate patterns by using the Apriori principle. Meanwhile, during the growing of the candidate head set in each round, the longest candidate patterns are used to find maximal frequent patterns from which the frequent patterns can be derived. Moreover, the PC-miner reduces the number of candidate patterns and comparisons by using several pruning techniques. A comprehensive experimental analysis is conducted by several experiments and scenarios to evaluate the correctness and effectiveness of the proposed method especially for interactive mining. The experimental results verify that the proposed method constructs the mining model independent of minsup once and this enable the model to be frequently mined. The results also show that the proposed method mines frequent patterns correctly and efficiently. Moreover, the results verify that the proposed method speeds up interactive mining of frequent patterns over both sparse and dense datasets with more scalable total runtime for very low values of minsup over sparse datasets as compared to results from the previous work
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
Performance and scalability of indexed subgraph query processing methods
Graph data management systems have become very popular
as graphs are the natural data model for many applications.
One of the main problems addressed by these systems is subgraph
query processing; i.e., given a query graph, return all
graphs that contain the query. The naive method for processing
such queries is to perform a subgraph isomorphism
test against each graph in the dataset. This obviously does
not scale, as subgraph isomorphism is NP-Complete. Thus,
many indexing methods have been proposed to reduce the
number of candidate graphs that have to underpass the subgraph
isomorphism test. In this paper, we identify a set of
key factors-parameters, that influence the performance of
related methods: namely, the number of nodes per graph,
the graph density, the number of distinct labels, the number
of graphs in the dataset, and the query graph size. We then
conduct comprehensive and systematic experiments that analyze
the sensitivity of the various methods on the values of
the key parameters. Our aims are twofold: first to derive
conclusions about the algorithmsâ relative performance, and,
second, to stress-test all algorithms, deriving insights as to
their scalability, and highlight how both performance and
scalability depend on the above factors. We choose six wellestablished
indexing methods, namely Grapes, CT-Index,
GraphGrepSX, gIndex, Tree+â, and gCode, as representative
approaches of the overall design space, including the
most recent and best performing methods. We report on
their index construction time and index size, and on query
processing performance in terms of time and false positive
ratio. We employ both real and synthetic datasets. Specifi-
cally, four real datasets of different characteristics are used:
AIDS, PDBS, PCM, and PPI. In addition, we generate a
large number of synthetic graph datasets, empowering us to
systematically study the algorithmsâ performance and scalability
versus the aforementioned key parameters
Making visible the invisible through the analysis of acknowledgements in the humanities
Purpose: Science is subject to a normative structure that includes how the
contributions and interactions between scientists are rewarded. Authorship and
citations have been the key elements within the reward system of science,
whereas acknowledgements, despite being a well-established element in scholarly
communication, have not received the same attention. This paper aims to put
forward the bearing of acknowledgements in the humanities to bring to the
foreground contributions and interactions that, otherwise, would remain
invisible through traditional indicators of research performance.
Design/methodology/approach: The study provides a comprehensive framework to
understanding acknowledgements as part of the reward system with a special
focus on its value in the humanities as a reflection of intellectual
indebtedness. The distinctive features of research in the humanities are
outlined and the role of acknowledgements as a source of contributorship
information is reviewed to support these assumptions.
Findings: Peer interactive communication is the prevailing support thanked in
the acknowledgements of humanities, so the notion of acknowledgements as
super-citations can make special sense in this area. Since single-authored
papers still predominate as publishing pattern in this domain, the study of
acknowledgements might help to understand social interactions and intellectual
influences that lie behind a piece of research and are not visible through
authorship.
Originality/value: Previous works have proposed and explored the prevailing
acknowledgement types by domain. This paper focuses on the humanities to show
the role of acknowledgements within the reward system and highlight publication
patterns and inherent research features which make acknowledgements
particularly interesting in the area as reflection of the socio-cognitive
structure of research.Comment: 14 page
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