关于METS用于资源集合的两个问题
METS网站上找了半天，还没有找到答案，先把问题记在这里：
- METS作为元数据方案的Wrapper，如何进行不同元数据方案的互操作（映射或者中介）？这个功能可能放在extension schema中的，或者通过Establish registry of METS repositories来实现？
- METS对于数字资源集合元数据的编码是否有用（通过它的structural map）？
元数据项目在编码方案方面应该参考METS：
METS Profile:
METS profiles allow digital libraries to specify constraints that they place on METS for ingest, storage/processing or dissemination, including:
- dictating use of particular extension schema, rules of description, and controlled vocabularies
- specifying arrangement and use of METS elements and attributes for particular classes of documents
- specifying the technical characteristics of data files within a METS object
- identifying tools for creating/processing METS documents compliant with a particular profile