Methodology for Architectural Level Reliability Risk Analysis

Lalitha KrothapalliCSC 532

Risk

Risk is a combination of two factors.

1. Probability of malfunctioning( failure)

2. Consequence of malfunctioning (severity)

Uses of Risk Assessment

Finding out the complex modules. Finding out the potentially

troublesome modules. Calculates the effort for testing.

Types of Risks

Availability Risk. Acceptance Risk. Performance Risk. Cost Risk. Schedule Risk Reliability Risk.

Architectural level System is divided in to two parts

Components: Like objects, classes or procedures.

Connectors: Procedural calls , Client- server protocols

Advantage of Architectural Risk Analysis

Early detection and correction of errors

Cost will be less. Design and coding are also depend

on the complexity of the architecture.

Advantages of simulating the Architecture Model

Obtain dynamic behavior of components and connectors using dynamic metrics.

Study the consequences of failure and severity of that failure.

Background

The proposed methodology is based on the previous work of Dynamic Metrics Reliability Modeling and Analysis of

Software Architecture

Dynamic Metrics Used to find out the complexity of each

component Executive components have lot of state

changes Measures the impact on the

maintainability, reusability and error proneness

Connector complexity can be calculated by using dynamic coupling metrics

Component Dependency Graphs

Used to find out the reliability analysis at the architectural level.

Represents components, connectors and component, connector reliabilities

Can be used to calculate the execution time of the components and the interaction between the components

Risk Assessment Methodology Usage of architectural description

language for modeling system architecture.

Calculate complexity analysis using simulation of the architecture.

Obtain severity analysis using FEMA and simulation runs.

Developing heuristic risk factors for components and connectors.

Preparing CDGs for calculating risk assessment.

Architectural Modeling

Interaction between the components

Behavior of individual components Real time object oriented model

can be used to simulate the architecture

Complexity Analysis

Component Complexity Connector complexity

Severity analysis Identifying failure modes. - failures modes of Individual components. - failure modes of individual connectors. Conducting Effect Analysis. Ranking severity.

Catastrophic Critical Marginal Minor.

Develop Reliability Risk Factors for Architecture Elements

Heuristic Factor for a component

Heuristic factor for a connector.

Developing Component Dependency Graphs

Calculate the execution time of each scenario.

Calculate the execution time of each component

Calculate the transition probability from one component to other for each and every scenario.

Predict the complexity factor and severity of the index of the each component.

Reliability Risk Analysis Algorithm

The risk factor of a system can be obtained from aggregating the risk factors of all components and connectors

Breadth of a graph - All risk factors

Depth of a graph - Sequential execution

Conclusion

Applicable to architecture level so the errors can identified and detected at the early stages of life cycle.

Based on dynamic metrics . Automatable.

References 1. Volume: 28,   Issue: 6,   Year: Jun 2002

A methodology for architecture-level reliability risk analysisYacoub, S.M.; Ammar, H.H.Page(s): 529-547

2. 1  Architectural-level risk analysis using UMLGoseva-Popstojanova, K.; Hassan, A.; Guedem, A.; Abdelmoez, W.; Nassar, D.E.M.; Ammar, H.; Mili, A.;Software Engineering, IEEE Transactions on , Volume: 29 , Issue: 10 , Oct. 2003 Pages:946 – 960

3. 7  Risk analysis-a subjective processRedmill, F.;Engineering Management Journal , Volume: 12 , Issue: 2 , April 2002 Pages:91 – 96