However: Ontologies are Hard! 但是: 本体论是很困难的!
Hard to implement a full ontology management system
很难实行一个完整的本体论管理系统
may be superfluous for some applications
对某些应用可能过剩
Hence the “onion” model of increasingly complex specs:
因此,像“洋葱”模式般愈来愈复杂的规格:
no property expressions or datatypes in RDF Schemas
在RDF schemas内没有内容表达或数据类
not all set operators, restricted cardinality in OWL Lite
并不是所有组合的操作者也受制于OWL Lite的
full expressive power in OWL Full (no computational guarantee)
全面表达力量于全部OWL内(没有计算的保证)
classes can themselves be instances
类别本身也可以是例子
classes of properties can be defined
内容的类别可以被定义
statements on properties are possible
内容的陈述是可能的
“Lite” < “DL” < “Full”, but not completely true for RDFS
“Lite” < “DL” < “Full”, 但于RDF中并不完全真确
RDFS is “almost” a subcategory
RDFS“差不多”是一个子分类
not all RDFS statements are valid in DL…
在DL内,并不是全部RDFS陈述也有效的...
…but they are for Full
但它们是为全部的
Applications may take what they really need!
应用时可提取它们真正所需!
Ivan Herman
, W3C Head of Offices
Beijing, China, 12 November, 2003
23 (35)