A Design Methodology for MPEG-21 based Digital Policy Management Systems

C

Building effective models from sparse but precise data

A common approach in computational science is to use a set of of highly precise but expensive calculations to parameterize a model that allows less precise, but more rapid calculations on larger scale systems. Least-squares fitting on a model that underfits the data is generally used for this purpose. For arbitrarily precise data free from statistic noise, e.g. ab initio calculations, we argue that it is more appropriate to begin with a ensemble of models that overfit the data. Within a Bayesian framework, a most likely model can be defined that incorporates physical knowledge, provides error estimates for systems not included in the fit, and reproduces the original data exactly. We apply this approach to obtain a cluster expansion model for the Ca[Zr,Ti]O3 solid solution.Comment: 10 pages, 3 figures, submitted to Physical Review Letter

First-principles study of ternary fcc solution phases from special quasirandom structures

In the present work, ternary Special Quasirandom Structures (SQSs) for a fcc solid solution phase are generated at different compositions, $x_A=x_B=x_C=\tfrac{1}{3}$ and $x_A=\tfrac{1}{2}$, $x_B=x_C=\tfrac{1}{4}$, whose correlation functions are satisfactorily close to those of a random fcc solution. The generated SQSs are used to calculate the mixing enthalpy of the fcc phase in the Ca-Sr-Yb system. It is observed that first-principles calculations of all the binary and ternary SQSs in the Ca-Sr-Yb system exhibit very small local relaxation. It is concluded that the fcc ternary SQSs can provide valuable information about the mixing behavior of the fcc ternary solid solution phase. The SQSs presented in this work can be widely used to study the behavior of ternary fcc solid solutions.Comment: 20 pages, 7 figure

ART-naive HIV patients at Feleg-Hiwot Referral Hospital Northwest, Ethiopia

Objectives: To determine socio-demographic and immunological status of anti-retroviral treatment (ART)-naïve HIVpositive patients.Methods: This was a longitudinal survey of HIV-positive patients treated with ART at Felege-Hiwot Hospital. CD4 cell counts were enumerated at baseline and after 6 months of treatment using FACS count (Becton Dickinson). Socioeconomic data were collected using pre tested questionnaires.Results: Three hundred sixty eight (62% female), with median age 30 years were enrolled. Of these, 207 (56.5%) were uneducated and 233 (66.8%) had monthly income ≤ 250 birr. Three hundred fifteen (85.6%) started ART within 6 months of HIV diagnosis. The mean (95% CI) CD4 cell count at baseline was 153 (139-167); 156 (137-175) for females and 122 cells/μl (105-139) for males (

The NCTM Standards: Implementation

In 1989 the National Council of Teachers of Mathematics published the Curriculum and Evaluation Standards for School Mathematics. The NCTM standards provides benchmark statements about specific aspects of the curriculum and about evaluation against which school divisions can judge their own specific curricula. The Standards has been a major focus of mathematics education since 1990. In the fall of 1992 the Metropolitan Educational Research Consortium undertook a study to determine the extent to which local schools were implementing the NCTM Standards. The study of the schools in the Consortium focused on the broad themes of the Standards document: mathematics as problem-solving, mathematics as communication, mathematics as reasoning, and mathematical communication. To teach with these four standard in mind is to teach in a Standards-oriented manner. This report summarizes the finding of three data sources collected from elementary, middle, and secondary school teachers and principals in the MERC school divisions: a survey of teachers, a survey of principals, and focus group interviews of selected teachers. The questions and discussions explore awareness of the Standards, classroom practices, and aids the obstacles to implementation

Hoe beoordelen topambtenaren veranderingen? De bijzondere positie van de Nederlandse topambtenaar

Dit artikel toont hoe topambtenaren in tien Europese landen veranderingen in de publieke sector beoordelen op een aantal dimensies, zoals kwaliteit, kostenefficiëntie, ethiek, effectiviteit en de aantrekkelijkheid van de publieke sector als werkgever. Nederlandse topambtenaren worden vergeleken met collega’s van negen andere Europese landen. Het onderzoek is gebaseerd op de grootschalige academische COCOPS Top Executive Survey. Voor dit artikel wordt gewerkt met een subsample van 3173 leidende ambtenaren. Resultaten tonen dat topambtenaren in Nederland positief zijn over veranderingen in de kostenefficiëntie en kwaliteit van de dienstverlening, maar zich zorgen maken over de aantrekkelijkheid van de overheid als werkgever en het vertrouwen van burgers in de overheid. Tegelijk zijn Nederlandse topambtenaren het meest positief over veranderingen in de werking van de publieke sector van alle ondervraagde topambtenaren. Enkel voor wat betreft de aantrekkelijkheid van de publieke sector als werkgever scoort Nederland eerder slecht in de Europese vergelijkin