24,900 research outputs found
Hadronic decays of the highly excited resonances
Hadronic decays of the highly excited resonances have been studied
in the model. Widths of all possible hadronic decay channels of the
have been computed. , ,
, and can be produced from hadronic decays
of the , and relevant hadronic decay widths have been particularly
paid attention to. The hadronic decay widths of to or
may be large, and the numerical results are different in different
assignments of and . The hadronic decay widths of
to , or are very small, and
different in different assignments of .Comment: 7 pages, 1 figure. High Energy Physics - Theor
The Sylvester equation and integrable equations: I. The Korteweg-de Vries system and sine-Gordon equation
The paper is to reveal the direct links between the well known Sylvester
equation in matrix theory and some integrable systems. Using the Sylvester
equation we introduce a scalar
function
which is defined as same as in discrete case. satisfy some
recurrence relations which can be viewed as discrete equations and play
indispensable roles in deriving continuous integrable equations. By imposing
dispersion relations on and , we find the
Korteweg-de Vries equation, modified Korteweg-de Vries equation, Schwarzian
Korteweg-de Vries equation and sine-Gordon equation can be expressed by some
discrete equations of defined on certain points. Some special
matrices are used to solve the Sylvester equation and prove symmetry property
. The solution provides function
by . We hope our results can not only
unify the Cauchy matrix approach in both continuous and discrete cases, but
also bring more links for integrable systems and variety of areas where the
Sylvester equation appears frequently.Comment: 23 page
Concept Extraction and Clustering for Topic Digital Library Construction
This paper is to introduce a new approach to build
topic digital library using concept extraction and
document clustering. Firstly, documents in a special
domain are automatically produced by document
classification approach. Then, the keywords of each
document are extracted using the machine learning
approach. The keywords are used to cluster the
documents subset. The clustered result is the taxonomy
of the subset. Lastly, the taxonomy is modified to the
hierarchical structure for user navigation by manual
adjustments. The topic digital library is constructed
after combining the full-text retrieval and hierarchical
navigation function
Automated Refactoring of Nested-IF Formulae in Spreadsheets
Spreadsheets are the most popular end-user programming software, where
formulae act like programs and also have smells. One well recognized common
smell of spreadsheet formulae is nest-IF expressions, which have low
readability and high cognitive cost for users, and are error-prone during reuse
or maintenance. However, end users usually lack essential programming language
knowledge and skills to tackle or even realize the problem. The previous
research work has made very initial attempts in this aspect, while no effective
and automated approach is currently available.
This paper firstly proposes an AST-based automated approach to systematically
refactoring nest-IF formulae. The general idea is two-fold. First, we detect
and remove logic redundancy on the AST. Second, we identify higher-level
semantics that have been fragmented and scattered, and reassemble the syntax
using concise built-in functions. A comprehensive evaluation has been conducted
against a real-world spreadsheet corpus, which is collected in a leading IT
company for research purpose. The results with over 68,000 spreadsheets with 27
million nest-IF formulae reveal that our approach is able to relieve the smell
of over 99\% of nest-IF formulae. Over 50% of the refactorings have reduced
nesting levels of the nest-IFs by more than a half. In addition, a survey
involving 49 participants indicates that for most cases the participants prefer
the refactored formulae, and agree on that such automated refactoring approach
is necessary and helpful
How Can We Predict Performance in Tertiary Level Economics?
The New Zealand Qualification Authority (NZQA) started to introduce a new qualification; the National Certificate of Educational Achievement (NCEA) in 2002. NCEA level 3 replaced the University Bursary Examinations in 2004. The main purpose of this paper is to investigate the relationship between the number and quality of credits gained at NCEA level 3 by students and their academic performance in a first year economics course - Business Economics and the New Zealand Economy at Waikato University. Other factors that could affect student performance are also investigated. Our analysis suggests that several factors can have an impact on student's performance in ECON100. These factors include nationality, semester, total number of NCEA level 3 credits and the quality of credits at level 3 in NCEA economics and mathematics.Qualification, Education, Testing, Teaching/Communication/Extension/Profession,
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