title: VQuery: a graphical user interface for Boolean query Specification and dynamic result preview

authors: Jones, Steve

subjects: computer science

abstract: Textual query languages based on Boolean logic are common amongst the search facilities of on-line information repositories. However, there is evidence to suggest that the syntactic and semantic demands of such languages lead to user errors and adversely affect the time that it takes users to form queries. Additionally, users are faced with user interfaces to these repositories which are unresponsive and uninformative, and consequently fail to support effective query refinement. We suggest that graphical query languages, particularly Venn-like diagrams, provide a natural medium for Boolean query specification which overcomes the problems of textual query languages. Also, dynamic result previews can be seamlessly integrated with graphical query specification to increase the effectiveness of query refinements. We describe VQuery, a query interface to the New Zealand Digital Library which exploits querying by Venn diagrams and integrated query result previews.

text: VQuery: a graphical user interface for Boolean query Specification and dynamic result preview Textual query languages based on Boolean logic are common amongst the search facilities of on-line information repositories. However, there is evidence to suggest that the syntactic and semantic demands of such languages lead to user errors and adversely affect the time that it takes users to form queries. Additionally, users are faced with user interfaces to these repositories which are unresponsive and uninformative, and consequently fail to support effective query refinement. We suggest that graphical query languages, particularly Venn-like diagrams, provide a natural medium for Boolean query specification which overcomes the problems of textual query languages. Also, dynamic result previews can be seamlessly integrated with graphical query specification to increase the effectiveness of query refinements. We describe VQuery, a query interface to the New Zealand Digital Library which exploits querying by Venn diagrams and integrated query result previews.

year: 1998-03

title: An empirical study of moment estimators for quantile approximation

authors: Mitchell, Rory

subjects: computer science

abstract: We empirically evaluate lightweight moment estimators for the single-pass quantile approximation problem, including maximum entropy methods and orthogonal series with Fourier, Cosine, Legendre, Chebyshev and Hermite basis functions. We show how to apply stable summation formulas to offset numerical precision issues for higher-order moments, leading to reliable single-pass moment estimators up to order 15. Additionally, we provide an algorithm for GPU-accelerated quantile approximation based on parallel tree reduction. Experiments evaluate the accuracy and runtime of moment estimators against the state-of-the-art KLL quantile estimator on 14,072 real-world datasets drawn from the OpenML database. Our analysis highlights the effectiveness of variants of moment-based quantile approximation for highly space efficient summaries: their average performance using as few as five sample moments can approach the performance of a KLL sketch containing 500 elements. Experiments also illustrate the difficulty of applying the method reliably and showcases which moment-based approximations can be expected to fail or perform poorly.

text: An empirical study of moment estimators for quantile approximation We empirically evaluate lightweight moment estimators for the single-pass quantile approximation problem, including maximum entropy methods and orthogonal series with Fourier, Cosine, Legendre, Chebyshev and Hermite basis functions. We show how to apply stable summation formulas to offset numerical precision issues for higher-order moments, leading to reliable single-pass moment estimators up to order 15. Additionally, we provide an algorithm for GPU-accelerated quantile approximation based on parallel tree reduction. Experiments evaluate the accuracy and runtime of moment estimators against the state-of-the-art KLL quantile estimator on 14,072 real-world datasets drawn from the OpenML database. Our analysis highlights the effectiveness of variants of moment-based quantile approximation for highly space efficient summaries: their average performance using as few as five sample moments can approach the performance of a KLL sketch containing 500 elements. Experiments also illustrate the difficulty of applying the method reliably and showcases which moment-based approximations can be expected to fail or perform poorly.

year: 2021

title: Rejoinder

authors: Kelly, Martin

abstract: Our paper (Kelly et al., 1999) set out to have points recognized as ‘needing to be addressed’ on the agendas of institutions currently providing accounting education. We believe that many institutions are continuing to fail to respond to recognized problems. We are grateful to the Commentators for recognizing our purpose. They note that our paper:
1. raises some important issues which need to be urgently addressed (Commentator 1);
2. illuminates why it is dif  cult to implement change even when there is a consensus to do so (Commentator 2);
3. provides a very important theme which has been neglected by many accounting educators (Commentator 3).

text: Rejoinder Our paper (Kelly et al., 1999) set out to have points recognized as ‘needing to be addressed’ on the agendas of institutions currently providing accounting education. We believe that many institutions are continuing to fail to respond to recognized problems. We are grateful to the Commentators for recognizing our purpose. They note that our paper:
1. raises some important issues which need to be urgently addressed (Commentator 1);
2. illuminates why it is dif  cult to implement change even when there is a consensus to do so (Commentator 2);
3. provides a very important theme which has been neglected by many accounting educators (Commentator 3).

year: 2000