Das delphische orakel in seinem politischen, religiösen und sittlichen einfluss auf die alte welt.

Mode of access: Internet.

Oraklet i Delfi; historie, religion, kunst.

Mode of access: Internet.

Fast rates for estimation error and oracle inequalities for model section

We consider complexity penalization methods for model selection. These methods aim to choose a model to optimally trade off estimation and approximation errors by minimizing the sum of an empirical risk term and a complexity penalty. It is well known that if we use a bound on the maximal deviation between empirical and true risks as a complexity penalty, then the risk of our choice is no more than the approximation error plus twice the complexity penalty. There are many cases, however, where complexity penalties like this give loose upper bounds on the estimation error. In particular, if we choose a function from a suitably simple convex function class with a strictly convex loss function, then the estimation error (the difference between the risk of the empirical risk minimizer and the minimal risk in the class) approaches zero at a faster rate than the maximal deviation between empirical and true risks. In this paper, we address the question of whether it is possible to design a complexity penalized model selection method for these situations. We show that, provided the sequence of models is ordered by inclusion, in these cases we can use tight upper bounds on estimation error as a complexity penalty. Surprisingly, this is the case even in situations when the difference between the empirical risk and true risk (and indeed the error of any estimate of the approximation error) decreases much more slowly than the complexity penalty. We give an oracle inequality showing that the resulting model selection method chooses a function with risk no more than the approximation error plus a constant times the complexity penalty.

访问Oracle���对象数据的技术及实现

主要介绍了在兰州重粒子加速器(HIRFL)Web网络数据库架构下,设计开发存取LOB(大对象)类型数据的COM组件接口,以此详细说明访问OracleLOB数据的技术和特点。

操作Oracle���BLOB字段的COM组件

介绍了在ATL下开发的一个利用Pro C/C ++操作Oracle���BLOB字段的COM组件。该COM组件已用于基于Webservices架构的实际控制系统中

Tutorial do Oracle Discoverer para análise do Armazém de Dados de Fruticultura.

Instruções de instalação e configuração. Análise de dados do comércio exterior: o tutorial. Iniciando o discoverer e estabelecendo conexão com o servidor. Abrindo um caderno de trabalho. Escolhendo um valor do item de página. Escolhendo outra folha de trabalho de um caderno. Visualizando diferentes níveis de detalhamento. Selecionando parâmetros. Renovando uma folha de trabalho. Alterando o eixo de uma dimensão. Classificando valores. Exportando ou enviando dados de um caderno de trabalho. Fechando um caderno de trabalho. Visualizando gráficos. Ramificando um gráfico. Alterando cores e padrões de um gráfico. Copiando um gráfico para outro documento.

Migração de banco de dados Oracle para PostgreSQL.

Preparação do ambiente operacional. Processo de migração do SGBD. Otimização de desempenho do PostgreSQL. Criação e restauração de cópias de segurança.