Tolerance of Siamese Networks (SNs) to Memory Errors: Analysis and Design Articles uri icon

authors

  • Wang, Ziheng
  • Niknia, Farzad
  • SHANSHAN, LIU
  • REVIRIEGO VASALLO, PEDRO
  • Montuschi, Paolo
  • Lombardi, Fabrizio

publication date

  • April 2023

issue

  • 4

volume

  • 72

International Standard Serial Number (ISSN)

  • 0018-9340

Electronic International Standard Serial Number (EISSN)

  • 1557-9956

abstract

  • This article considers memory errors in a Siamese Network (SN) through an extensive analysis and proposes two schemes (using a weight filter and a code) to provide efficient hardware solutions for error tolerance. Initially the impact of memory errors on the weights of the SN (stored as floating-point (FP) numbers) is analyzed; this shows that the degradation is mostly caused by outliers in weights. Two schemes are subsequently proposed. An analysis is pursued to establish the filter's bounds selection by the maximum/minimum values of the weight distributions, by which outliers can be removed from the operation of the SN. A code scheme for protecting the sign and exponent bits of each weight in an FP number, is also proposed; this code incurs in no memory overhead by utilizing the 4 least significant bits (LSB) to store parity bits. Simulation shows that the filter has a better performance for multi-bit errors correction (a reduction of 95.288% in changed predictions), while the code achieves superior results in single-bit errors correction (a reduction of 99.775% in changed predictions). The combined method that uses the two proposed schemes, retains their advantages, so adaptive to all scenarios; The ASIC-based FP designs of the SN using serial and hybrid implementations are also presented; these pipelined designs utilize a novel multi-layer perceptron (MLP) (as branch networks of the SN) that operates at a frequency of 681.2 MHz (at a 32nm technology node), so significantly higher than existing designs found in the technical literature. The proposed error-tolerant approaches also show advantages in overheads comparing with for example traditional error correction code (ECC). These error-tolerant MLP-based designs are well suited to hardware/power-constrained platforms.

keywords

  • error tolerance; floating point; memory error; siamese network; vlsi design