Improvement of complexity matrix of IFPUG in embedded-software projects

IFPUG is a widely used functional size measurement method, but when applied in embedded software project, the measurement results and the actual sizes have big deviations. The paper finds that functional types with low complexity of embedded software is relatively large, so proposes to refine and adjust the low level part of complexity matrix. Measure the same software projects based on adjusted complexity matrix, the deviation of measurement results reduced from 24%~73.4% to 3.8%~38.8%, and the average deviation reduced from 45.7% to 12.8%.