Theoretical and empirical validation of software trustworthiness measure based on the decomposition of attributes

Figures & data

Figure 1. Measurement procedure based on STMBDA.

Table 1. Trustworthy attributes, sub-attributes of spacecraft software and their weight values.

Attribute	Attribute weight value	Sub-attribute	Sub-attribute weight value
1. Test verification	0.20	(1) Test plan and implementation	$w_{1,1}=0.16$
		(2) Code walk through and static analysis	$w_{1,2}=0.17$
		(3) Test content comprehensiveness	$w_{1,3}=0.17$
		(4) Special testing situation	$w_{1,4}=0.17$
		(5) Test coverage	$w_{1,5}=0.17$
		(6) Test environment, methods and tool usage	$w_{1,6}=0.16$
2. Analysis and design	0.17	(7) Input file controlled condition	$w_{2,7}=0.33$
		(8) Demand analysis	$w_{2,8}=0.33$
		(9) Software design	$w_{2,9}=0.34$
3. Reliability and safety	0.15	(10) Reliability and safety analysis	$w_{3,10}=0.33$
		(11) Reliability and safety design	$w_{3,11}=0.34$
		(12) Reliability and safety verification	$w_{3,12}=0.33$
4. Configuration management	0.11	(13) Configuration management organisation, requirements, and tools	$w_{4,13}=0.33$
		(14) Change control situation	$w_{4,14}=0.34$
		(15) Configuration audit, documentary	$w_{4,15}=0.33$
5. Software technology status change	0.09	(16) Basis, demonstration and approval of technical status change	$w_{5,16}=0.34$
		(17) Tests and verifications after changes	$w_{5,17}=0.33$
		(18) Implementations after changes	$w_{5,18}=0.33$
6. Quality problem close loop	0.09	(19) Quality problem zero completion	$w_{6,19}=0.50$
		(20) Implementation of one example against three tasks	$w_{6,20}=0.50$
7. Third party evaluation situation	0.09	(21) Evaluation input and evaluation plan situation	$w_{7,21}=0.33$
		(22) Evaluation of implementation	$w_{7,22}=0.33$
		(23) Problem solving situation	$w_{7,23}=0.34$
8. Overall planning and implementation	0.05	(24) Development planning and execution	$w_{8,24}=0.31$
		(25) Functionality and performance compliance with specification	$w_{8,25}=0.36$
		(26) Integrity of software development documentation	$w_{8,26}=0.33$
9. Software development environment	0.05	(27) Development supporting software	$w_{9,27}=0.50$
		(28) Development supporting hardware	$w_{9,28}=0.50$

Figure 2. Distributions of sub-attribute values of 11 representative software.

Figure 3. Distributions of attribute values of 11 representative software.

Figure 4. Distributions of trustworthy degrees of 11 representative software.

Table 2. Comparative study by the properties introduced in Section 3.

Property	STMBDA	PBSTM1	PBSTM2	PBSTM3	FTBSTM	ERBSTM
Non-negativity	√	√	√	√	√	√
Proportionality	√	×	×	×	×	×
Monotonicity	√	√	√	√	√	√
Acceleration	√	√	√	√	×	×
Sensitivity	√	√	×	√	√	√
Substitutivity	√	√	√	√	×	×
Expectability	√	×	×	√	√	√