Managing and Querying Multi-Version XML Data with Update Logging

With the increasing popularity of storing content on the WWW and intranet in XML form, there arises the need for the control and management of this data. As this data is constantly evolving, users want to be able to query previous versions, query changes in documents, as well as to retrieve a particular document version efficiently. This paper proposes a version management system for XML data that can manage and query changes in an effective and meaningful manner

Automatic estimation of flux distributions of astrophysical source populations

In astrophysics a common goal is to infer the flux distribution of populations of scientifically interesting objects such as pulsars or supernovae. In practice, inference for the flux distribution is often conducted using the cumulative distribution of the number of sources detected at a given sensitivity. The resulting "$\log(N>S)$-$\log (S)$" relationship can be used to compare and evaluate theoretical models for source populations and their evolution. Under restrictive assumptions the relationship should be linear. In practice, however, when simple theoretical models fail, it is common for astrophysicists to use prespecified piecewise linear models. This paper proposes a methodology for estimating both the number and locations of "breakpoints" in astrophysical source populations that extends beyond existing work in this field. An important component of the proposed methodology is a new interwoven EM algorithm that computes parameter estimates. It is shown that in simple settings such estimates are asymptotically consistent despite the complex nature of the parameter space. Through simulation studies it is demonstrated that the proposed methodology is capable of accurately detecting structural breaks in a variety of parameter configurations. This paper concludes with an application of our methodology to the Chandra Deep Field North (CDFN) data set.Comment: Published in at http://dx.doi.org/10.1214/14-AOAS750 the Annals of Applied Statistics (http://www.imstat.org/aoas/) by the Institute of Mathematical Statistics (http://www.imstat.org

Can education improve tax compliance? Evidence from different forms of tax education

We examine whether tax compliance is improved via different forms of tax education. We argue that different types of tax education have respective impacts on tax compliance. To explore this empirical issue, we conduct a survey related to tax compliance among 205 students taking either a general tax course or a technical tax course in Hong Kong. Our findings suggest that sales tax compliance among undergraduate students was significantly improved if they had been exposed to a general tax education, and income and sales tax compliance among postgraduate students were significantly improved if they had taken a technical tax course