there has been a recent development and explosion of interest among academicians across a wide range of disciplines in the use of virtual class room. utilization of the virtual class room as a laboratory experimentation for teaching and learning has increased significantly in recent years as development tools for web based applications have become easier to use and computers have become more ca...

We show how the use of a metaobject layer is useful to allow an easier evolution of a an object-oriented database integrating existing relational systems. A correct use of metaobjects allow to hide the persistence contingencies when linking an application with an external application. Moreover a metaobject layer allows the evolution of the database object model. We show in these lines how a und...

Persistent homology and zigzag persistent homology are techniques which track the homology over a sequence of spaces, outputting a set of intervals corresponding to birth and death times of homological features in the sequence. This paper presents a method for choosing a homology class to correspond to each of the intervals at each time point. For each homology class a specific representative c...

The recognition problem for visibility graphs of simple polygons is not known to be in NP, nor is it known to be NP-hard. It is, however, known to be in PSPACE. Further, every such visibility graph can be dismantled as a sequence of visibility graphs of convex fans. Any nondegenerate configuration of n points can be associated with a maximal chain in the weak Bruhat order of the symmetric group...

In this paper, we examine Decision Graphs, a generalization of decision trees. We present an inference scheme to construct decision graphs using the Minimum Message Length Principle. Empirical tests demonstrate that this scheme compares favourably with other decision tree inference schemes. This work provides a metric for comparing the relative merit of the decision tree and decision graph form...

we have analysed data from 150 patients initially classified as having cvid. about 10% had laboratory abnormalities suggesting known single gene disorders (eg: hyper-igm syndrome), and in a few a genetic defect has been confirmed. we have attempted to sub-classify the remaining patients by analysis of their circulating lymphocytes. b lymphocyte markers have been used to estimate the numbers of ...

late ripening citrus cultivars are very acceptable in the market. with respect to scarcity of late ripening citrus cultivars in iran, the project was conducted to produce a new late ripening cultivar for 21 years (1989-2009). the first phase (1989-1993) was started with controlled pollination between mineolla tangelo (citrus paradisi × c. reticulata) and changsha mandarin (c. changsha). after a...

Knowing the overall solute flux and the partial fluxes expressed by every single transport layer, the membrane internal interface concentrations can separately be expressed. Both the overall transport coefcient and the driving force strongly depend, among others, on the value of the structural parameter and the water permeability. Study of the interface concentrations as ...

OBJECTIVE To evaluate surgical results using the middle cranial fossa approach for hearing preservation vestibular schwannoma surgery. STUDY DESIGN Retrospective case review. SETTING Tertiary referral academic center. PATIENTS Seventy-three consecutive patients with vestibular schwannoma operated on using the middle cranial fossa approach between February 1999 and February 2005. INTERVE...