CSE 322: Software Reliability Engineering

Topics covered:Architecture-based reliability analysis

Introduction and motivation

Benefits of architecture-based analysis

Application architecture

Architecture:

Components:

Interactions:

Application architecture (contd..)

Sequential application:

Dynamic behavior:

Application architecture (contd..)

Types of applications:

Application architecture (contd..)

Models used:

Mapping of control-flow graph to models:

Application architecture (contd..)

Type of models:

DTMC analysis

Overview of DTMCs:

Absorbing:

Irreducible:

Analysis of absorbing DTMCs

Analysis of absorbing DTMCs (contd..)

Analysis of irreducible DTMCs

Example of architecture analysis

•Terminating application•10 modules•1 is the input, 10 is the exit module•Architecture modeled by absorbing DTMC

jip , Probability that the control istransferred to module j, uponexecution of module i

11

22 33 44

55 66

77 88 99

1010

2,1p3,1p

4,1p

3,2p

2,7p

5,2p 5,3p3,6p

5,4p6,4p

7,5p8,5p

8,6p

9,7p10,8p

8,9p

10,9p

9,6p

4,9p

7,6p 4,8p

Example of architecture analysis (contd..)

60.02,1 p 20.03,1 p 20.04,1 p

70.03,2 p 30.05,2 p

00.15,3 p

40.05,4 p 60.06,4 p

40.07,5 p 60.08,5 p

30.03,6 p 30.07,6 p 10.08,6 p 30.09,6 p

50.02,7 p 50.09,7 p

25.04,8 p 75.010,8 p

10.08,9 p 90.010,9 p

Intercomponent transition probabilities

Example of architecture analysis (contd..)

Component i 2i

1 1.0000 0.0000

2 0.9077 0.6444

3 0.9107 0.5499

4 0.4184 0.3928

5 1.3504 0.7185

6 0.2510 0.2319

7 0.6155 0.6261

8 0.8737 0.4225

9 0.3831 0.2462

10 1.0000 0.0000

i2iMean number of visits

Variance of the number of visits

Computed for component i

Example of architecture analysis (contd..)

•Non-terminating application•10 modules•Architecture modeled by irreducible DTMC •Reliability of each component known

jip , Probability that the control istransferred to module j, uponexecution of module i

11

22 33 44

55 66

77 88 99

1010

2,1p3,1p

4,1p

3,2p

5,2p 5,3p3,6p

5,4p6,4p

7,5p8,5p

8,6p

9,7p10,8p

8,9p

10,9p

9,6p

4,9p

7,6p 4,8p

1,10p

4,10p

2,7p

Example of architecture analysis (contd..)

Intercomponent transition probabilities

60.02,1 p 20.03,1 p 20.04,1 p

70.03,2 p 30.05,2 p

00.15,3 p

40.05,4 p 60.06,4 p

40.07.5 p 60.08,5 p

30.03,6 p 30.07.6 p 10.08,6 p 30.09,6 p

50.02,7 p 50.09,7 p

25.04,8 p 75.010,8 p

10.08,9 p 90.010,9 p

8.01,10 p 20.04,10 p

Addition oftwo transitionsto absorbingDTMC to makeit irreducible

Example of architecture-based analysis (contd..)

Component iu1 0.1073

2

3

4

5

6

7

8

9

10

0.1055

0.1091

0.0765

0.1714

0.0459

0.0823

0.1129

0.0549

0.1341

iu Utilization of the component

Computed for component i