The constraint conditions of normal optimal model are usually rigid constraint conditions under the determined factors which may lead to exclude some excellent schemes.

常规的优化模型的约束条件都是在确定因素下进行的硬性约束，这样做的直接后果是可能排除掉了一些较优秀的方案。

youdao

Usually, these are sets of pages within a site that are either dynamically generated from queries (but thereby having consistent patterns) or are pre-generated following fairly rigid templates.

通常，站点中的一些页面是由查询动态生成(但是具有一致的模式)，或是根据非常严格的模板预先生成。

youdao

I can understand this limitation: it's not usually easy to superimpose a regular lattice of information upon an XML document; such is the mismatch between extensible hierarchies and rigid tables.

我完全理解这种局限性，要将规整的信息表格添加到XML文档通常并非易事，这就是可扩展层次结构和严整表格的不匹配。

youdao

That isn't an option for charities, religious groups and other nonprofits, which usually can't pass along the fees because of rigid credit-card rules.

WSJ: Getting Going: Is Your Charity Chiseling You?

Twenty years ago, neuroscientists held that after a certain critical period, usually no more than the first 12 months of life, the entire visual system has become far too rigid for any real learning to take place.

FORBES: Downloadable Learning -- Matrix Style: Welcome to Education's Laziest Frontier