BM+-tree: A hyperplane-based index method for high-dimensional metric spaces

In this paper, we propose a novel high-dimensional index method, the BM+-tree, to support efficient processing of similarity search queries in high-dimensional spaces. The main idea of the proposed index is to improve data partitioning efficiency in a high-dimensional space by using a rotary binary hyperplane, which further partitions a subspace and can also take advantage of the twin node concept used in the M+-tree. Compared with the key dimension concept in the M+-tree, the binary hyperplane is more effective in data filtering. High space utilization is achieved by dynamically performing data reallocation between twin nodes. In addition, a post processing step is used after index building to ensure effective filtration. Experimental results using two types of real data sets illustrate a significantly improved filtering efficiency.

Virtual teachers: Negotiating new spaces for teaching bodies

In 2002, the authors reviewed the educational performance of a state education department virtual schooling service during its first 2 years of operation, 2000-2001 (Pendergast, Kapitzke, Land, Luke, & Bahr, 2002). Established by Education Queensland, the Virtual Schooling Service (VSS) utilises synchronous and asynchronous online delivery strategies and a range of learning technologies to support students at a distance (see http://education.qld.gov.au/learningplace/vss/). The service commenced with a focus on senior secondary subjects. At present, there are over 700 students in 89 schools across the state enrolled in 9 subjects. In response to the recommendations of the study, a series of professional development activities were conducted with the VSS teachers by the authors. Opportunity for critical reflection was provided, including consideration of the ways in which the teachers were developing as a learning community. Some data, including visual representations, were collected from participants with the purpose of understanding how VSS teachers are constructed as professionals. This study compares and contrasts that data with self-constructions of teacher professionals in other fields.