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2.2 Data Compression 数据压缩
The way a computer represents data internally is different from the way the data are interpreted and displayed for the user. Programs are used to translate data into a representation more easily understood by people.
- 计算机内部表示数据的方式与数据被解释和显示给用户的方式不同。程序用于将数据转换为更容易被人们理解的表示形式。
核心要点 Core Points
Data compression can reduce the size (number of bits) of transmitted or stored data.
- 数据压缩可以减少传输或存储数据的大小（位数）。
Fewer bits does not necessarily mean less information.
- 更少的位不一定意味着更少的信息。
The amount of size reduction from compression depends on both the amount of redundancy in the original data representation and the compression algorithm applied.
- 压缩的大小减少量取决于原始数据表示中的冗余量和应用的压缩算法。
Lossless data compression algorithms can usually reduce the number of bits stored or transmitted while guaranteeing complete reconstruction of the original data.
- 无损数据压缩算法通常可以减少存储或传输的位数，同时保证原始数据的完全重建。
Lossy data compression algorithms can significantly reduce the number of bits stored or transmitted but only allow reconstruction of an approximation of the original data.
- 有损数据压缩算法可以显著减少存储或传输的位数，但只允许重建原始数据的近似值。
Lossy data compression algorithms can usually reduce the number of bits stored or transmitted more than lossless compression algorithms.
- 有损数据压缩算法通常可以比无损压缩算法更多地减少存储或传输的位数。
In situations where quality or ability to reconstruct the original is maximally important, lossless compression algorithms are typically chosen.
- 在质量或重建原始数据的能力极其重要的情况下，通常选择无损压缩算法。
In situations where minimizing data size or transmission time is maximally important, lossy compression algorithms are typically chosen.
- 在最小化数据大小或传输时间极其重要的情况下，通常选择有损压缩算法。
学生活动 Student Activities
- Compare data compression algorithms to determine which is best in a particular context.
- 比较数据压缩算法以确定在特定情况下哪种是最好的。
相关资源 Related Resources
- Text Compression from CS Unplugged
- 文本压缩 来自CS Unplugged
必背单词
- transmit 传输
- redundancy 冗余
- reconstruction 重建
- significant 重要的，显著的
- Lossless compression 无损压缩
- Lossy compression 有损压缩