A Requirements Engineering Process for Embedded Systems

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A Requirements Engineering Process for Embedded Systems

Tarcísio Couto Pereira

tcp@cin.ufpe.br

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Outline

• Context and Motivation;

• Research Goals and Questions;

• Systematic Literature Review;

• Requirements Engineering Standards;

• REPES Process;

• Assessment and Evolution of the Process;

• Conclusions.

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Context and Motivation

• BROY. (1999) define Embedded System as a system that regulate a physical device by sending control signals to actuators in reaction to input signals provided by its users and by sensors capturing the

relevant state parameters of the system.

• According to BROY; STAUNER (1999), in the embedded system domain, more than 50% of the problems occur when the system is delivered (misconceptions in capturing requirements).

• The use of RE good practices is associated with the success of

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Context and Motivation

• Embedded Systems complexity.

• There is a shortage of processes, methods, techniques, and requirements engineering tools specially developed for the ES domain (OSSADA, 2010);

• In order to verify if RE is a problem in the ES domain, we

performed a SLR (KEELE, 2007) to evaluate and synthesize the evidence available in the literature;

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Research Objective

• This work proposes a particular requirements engineering process by providing inputs, outputs, and work products for correct requirements development and management for the scope of embedded systems.

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Research Questions

• RQ1. What is the state of the art on requirements engineering for embedded systems?

• RQ2. What should be taken into account in the development of requirements engineering for embedded systems?

• RQ3. How should a systematic requirements engineering process for embedded systems be developed?

• RQ4. How should the feasibility of the new requirements

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Overview of the Research

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Systematic Literature Review Process

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Systematic Literature Review (SLR)

• Research Questions

– “What requirements should be considered during embedded systems development?”

– “What are the requirements engineering contributions for embedded systems?”

– “What challenges/problems are identified in research literature relating to RE for ES?”

– “What are the domains that the approaches support?”

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Systematic Literature Review (SLR)

• The most relevant findings from the SLR and their implication for further research are as follows:

– Need to improve the specification and analysis of timing requirements;

– Need to improve the specification and analysis of the NFRs;

– Need of integration tools;

– Need to apply the studies on real industry projects;

– Need to include RE standards;

– A need for the development of specific RE processes to support the development of embedded systems;

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Requirements Engineering Standards

• A RE for Embedded Systems is challenging since it has

unique properties that make it complex, expensive and error- prone.

– (i) Embedded Software Systems (ESS) are usually tightly coupled to their physical environment;

– (ii) the context of ESS require a very broad range of stakeholders with different roles;

– (iii) the interaction interfaces are mostly hardware components;

– (iv) Hardware Requirements Specification (HRS) is as important

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Requirements Engineering Standards

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Requirements Engineering Standards

• Relation among the standards and the key factors;

• The key factors were identified in our SLR and MM4ES;

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Metamodel Development Process

• According to our SLR, no evidence explicitly depicts how an ES must be elicited and specified;

• What should be considered in ES development?

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Metamodel Development Process - MM4ES

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Metamodel Development Process - MM4ES

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Metamodel Development Process - MM4ES

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REPES

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REPES

• Relation among the embedded systems key factors and

the REPES tasks.

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Survey Based on Expert Opinion

• Expert Opinion is about “the speculations, guesses, and

estimates of people who are considered experts in so far as these serve as “cognitive input” in some decision process”

• The expert opinion method has been used to: evaluate the success of a project using subjective factors.

• Research question: “Is the REPES process viable,

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Survey Based on Expert Opinion

• The survey will be composed of a questionnaire adapted from GARCIA (2010).

• The questionnaire is related to issues such as:

– the way the levels are distributed in the process;

– the specification, description and main goal of the levels;

– goals related to the tasks of the levels;

– inputs, outputs, and work products related to the goals/tasks;

– possible gaps in the evolution prescribed by each level of the process; and,

– the difficulty in evolving through the levels of the process;

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GQM Paradigm

Questions: Motorola assessment instrument.

Metrics: RE Maturity Measurement Framework

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GQM Paradigm

• Results – Example

poor (0), weak (2), fair (4), marginally qualified (6), qualified (8), and outstanding (10)

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Conclusion

• RQ1. What is the state of the art on requirements engineering for embedded systems?

• We have conducted a SLR to investigate how RE is used in the embedded systems context;

• RQ2. What should be taken into account in the development of requirements engineering for embedded systems?

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Conclusion

• RQ3. How should a systematic requirements engineering process for embedded systems be developed?

• Requirements engineering standards;

• REPES process;

• [ONGOING] RQ4. How should the feasibility of the new requirements engineering process be validated?

• Survey based on expert opinion;

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Conclusion – SWOT Analysis

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Thank You!

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