EAGER: Digital Yet Deliberately Random -- Synthesizing Logical Computation on Stochastic Bit Streams

EAGER：数字但故意随机——在随机比特流上综合逻辑计算

• 批准号: 1241987
• 负责人: Marc Riedel
• 金额: $ 30万
• 依托单位: University of Minnesota-Twin Cities
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2012
• 资助国家: 美国
• 起止时间: 2012-07-01 至 2015-06-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1241987&HistoricalAwards=false
• 关键词: EAGER; Digital; Yet; Deliberately; Random

Most digital systems operate on a positional representation of data, such as binary radix. This project advocates an alternative representation: random bit streams where the signal value is encoded by the probability of obtaining a one versus a zero. This representation is much less compact than binary radix. However, complex operations can be performed with very simple logic. In particular, arithmetic functions, consisting of operations like addition and multiplication can be implemented very efficiently. Complex functions, such as exponentials and trigonometric functions, can be computed through polynomial approximations. Because a stochastic representation is uniform, with all bits weighted equally, it is highly tolerant of soft errors (i.e., bit flips). Computation on stochastic bit streams offers tunable precision: as the length of the stochastic bit stream increases, the precision of the value represented by it also increases. Thus, without hardware redesign, one has the flexibility to tradeoff precision and computation time. In contrast, with a conventional binary-radix implementation, when a higher precision is required, the underlying hardware has to be redesigned. This project will develop and apply a unified framework for synthesizing such computation from the circuit level to the architectural and system level. Techniques for transforming probability values with combinational logic will be developed. As part of this grant, a new course on "Circuits, Computation, and Biology" offered jointly through the ECE Department and the new Biomedical Informatics and Computational Biology Program at the University of Minnesota. The researchers will try to incorporate stochastic ideas in computer design curriculum, The PIs will focus on building upon current research efforts that include female and underrepresented students.

大多数数字系统都在数据的位置表示（例如二进制radix）上运行。该项目主张替代表示：随机位流，其中信号值是通过获得一个与零的概率编码的。该表示不如二进制radix少得多。但是，可以使用非常简单的逻辑执行复杂的操作。特别是，可以非常有效地实现由加法和乘法等操作组成的算术功能。可以通过多项式近似来计算复杂函数，例如指数和三角函数。因为随机表示均匀，所有位均等加权，所以它高度耐受性误差（即位翻转）。随机位流上的计算具有可调的精度：随机位流的长度增加，其代表的值的精度也会增加。因此，如果没有硬件重新设计，就可以灵活地权衡精度和计算时间。相比之下，使用常规的二进制 - radix实现，当需要更高的精度时，必须重新设计基础硬件。该项目将开发并应用一个统一的框架，以将从电路级别到体系结构和系统级别的此类计算综合。将开发用于通过组合逻辑转换概率值的技术。作为这笔赠款的一部分，通过ECE部门共同提供了有关“电路，计算和生物学”的新课程，以及明尼苏达大学的新生物医学信息学和计算生物学计划。研究人员将尝试将随机思想纳入计算机设计课程中，PI将专注于建立当前的研究工作，包括女性和代表性不足的学生。