Before analyzing Lucene's index file structure, you should understand the inverted index concept. An inverted index is an inside-out arrangement of documents in which terms take center stage.

在分析Lucene的索引文件结构之前，我们先要理解反向索引(Inverted index)这个概念，反向索引是一种以索引项为中心来组织文档的方式，每个索引项指向一个文档序列，这个序列中的文档都包含该索引项。

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Many programming languages support the concept of a field index for accessing a particular occurrence of a repeating field.

许多编程语言支持字段索引的概念，字段索引用于访问重复字段的特定实例。

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In this first part, we will look at the concept of the guest satisfaction index: the next big measure of hotel performance.

在本文第一部分，我们先来看看客人满意度指数(guest satisfaction index)这个概念——衡量酒店业绩的下一个重要指标。

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At Index Ventures, we have modelled the early stage development process (up to proof of clinical concept) on the presumption that the majority of the risk in a discovery programme is not only unknown but it also unknowable (ahead of testing in man).

FORBES: Are We The Problem? The Role Of Poor Decision-Making In Stifling Drug Development