Quality for Components: Component and Component-Based Software Quality Issues

1
Quality for Components Component and
Component-Based Software Quality Issues

• Yusuf Altunel
• Istanbul Kültür University, Department of
  Computer Engineering
• Mehmet R. Tolun
• Çankaya University, Department of Computer
  Engineering

2
Outline

• Software components
• and component-based software systems
• have the capacity to
• enhance the productivity,
• reduce the time-to-market, and
• increase the confidence on the software.
• Build up software out of reusable components
• satisfying the quality requirements
• helps to meet the goals of software production.
• The problems of the component market
• and the market-oriented components
• prevent the wide application of component based
  software production.
• In this paper we investigate
• the quality related problems of CBD
• and the possible solutions.

3
Introduction

• Quality focus in component-based software
  engineering (CBSE)
• is the base layer
• methodology in the area must be based on
• Component market,
• is a priori condition to maximize the
  intra-organizational software reusability,
• cannot emerge without supplying high-quality
  products
• Building up software out of components
• Requires sufficient number of market components
• To make the selection out of choices
• Common belief
• Market components are not reliable
• Prevents the emergence of mature market.
• Solution
• Resolve quality problems of market components
• Third-party certification programs.

4
Definition Product Quality

• ensuring the satisfaction of functional and
  non-functional characteristics, which will
  determine the level of user satisfaction and
  conforming expectations
• product characteristics
• Some will reduce the software quality,
• Some are neutral,
• some will reduce the quality.
• Software quality is defined as the level of a
  software system possessing the desired set of
  attributes 6, and lacking the undesired
  characteristics
• There is a need to define a methodology
• to specify softwares quality-related
  characteristics
• To define metrics to objectively measure
  products quality

5
Definitions

• A quality attribute
• a quality property representing
• a non-functional characteristics of a software
  system
• to assign a metric
• is a non-functional characteristic of a software
  system
• Examples
• functionality, reliability, usability,
  efficiency, maintainability, and portability.
• A quality model
• the set of characteristics and sub-characteristics
  
• to provide a basis in specifying the quality
  requirements of a software system

6
Quality Assurance (QA)

• Helps to localize the effects of changes
• on the product reducing the ripple effects.
• Component-based Quality Assurance
• Increasing the modularity using components
• will increase the speed of incremental delivery
• help the developers to reduce time-to-market.
• Component reuse might cause
• integration difficulties,
• performance problems,
• incompatibility among products of different
  vendors.
• reliability and performance problems
• due to poor testing
• The main focus in CBD quality assurance
• to maximize the product quality
• adequately describe the quality characteristics
• increase the conformance to the standards

7
Importance of QA

• Trusting to the code
• constructed outside of the organization
• is a basic prerequisite
• to widespread use of commercial of-the-shelf
  (COTS) components
• Third-party component licensing
• To increase the trustworthiness of the components
• To discipline and enhance the overall quality of
  market components.
• confidence on the market components maintained
• showing the components satisfy
• functional and non-functional requirements.
• quality assurance activities help
• Increasing the externally developed software code
  reuse
• Appearing more suitable market conditions

8
Component Quality Assessment

• A metric for quality measurement
• a value that can be assigned to a quality
  attribute.
• To assess component quality
• define quality metrics with
• statistical evidence showing the correspondence
  between the quality and its metrics.
• code oriented measure is generally not feasible
• due to the lack of the source code for outsourced
  components.
• Quality metrics are used
• to evaluate the quality level of components
• before making the purchase or develop decisions.

9
CBSE Metrics

• Management metrics
• cost,
• time to market,
• software engineering environment
• system resource utilization.
• Requirements metrics
• requirements conformance,
• requirements stability.
• Quality oriented metrics
• adaptability,
• complexity of interfaces and integration,
• integration test coverage,
• end-to-end test coverage,
• fault profiles,
• reliability,
• customer satisfaction

10
CBSE and Organization-wide Quality Improvement

• Strong interrelationship between CBSE and
  Organization-wide quality improvement
• set up tasks
• Producing quality plan ,
• Define and apply quality and productivity
  measures,
• Investigate the measures and measure results,
• Execute correction actions,
• Analyse the results.
• Some reasons of unsuccessful CBSE projects
• Low process maturity,
• lacking the coordination and management,
• absence of
• well-tested, undocumented and ill-defined reuse
  oriented
• methods, models, and processes

11
Enhancement of CBSE Quality

• Component manufacturers
• Establish organization-wide assessment standards.
  
• Discover the rules to define such standards
• Use the knowledge obtained from previous projects
  
• to adjust component production activities.
• Component consumers
• Reuse might improve overall software quality
• Components are reusable software units
• Provide efficient reuse
• To reduce the quality assurance effort and
  integration problems

12
Issues in Implementing Systematic Reuse

• Managerial issues
• to promote and reward reuse,
• Economic issues
• to make reuse economical,
• Legal issues
• to protect the legal rights of reuse
• Technical issues
• to apply technical variables
• design method,
• coding standards and practices,
• reuse library indexing methods.

13
Cost of Quality

• Costs of lacking the quality
• Internal failure costs
• the defects determined prior to
• delivery of shipment of the product
• Measured to analyse and improve
• the component development process
• External failure costs
• occur after the delivery or shipment of the
  product
• cover efforts to detect and correct problems
• Costs to achieve quality
• Appraisal costs
• costs of measuring, evaluating, or auditing
  products
• assure conformance
• to quality standards and performance
  requirements.
• Measured for cost/benefit analysis
• To produce higher quality components and
  component-based software
• Prevention costs
• Costs associated with activities designed
• to keep failure and appraisal costs to minimum

14
Conclusions

• The lack-of-the quality
• is a general problem of software development
• has a vital importance for CBSE
• An obstacle preventing the wide application of
  the CBSE.
• CBSE provides a radical change in software
  development
• construct the software systems out of quality
  components
• instead of developing every piece of code from
  scratch.
• wide application of software
• developed outside of the organization.
• confidence on the software developed outside of
  the organization
• the component producers must concentrate on
  quality issues
• Deal with extra costs and further activities
• Extra resource allocation
• increasing and assuring quality,
• identifying and mitigating the risks related with
  the quality
• quality planning and tracking activities

15
Conclusion-contd

• Radical change is required to
• Existing software development style
• Software development culture
• continuous process improvement.
• Define formal processes
• Regular data collection
• to assess and improve the development
• Classical SW development methodologies
• not useful to reduce
• the number of failures lower than a certain
  level,
• Reason every piece of code is developed from
  scratch
• Component defects
• Must be minimized in component-based software
  production.
• New SW development methodology
• To constructs SW out of qualified components
• Making the whole system
• More trustable,
• more efficient,
• easier to maintain

16
End of Presentation

• Questions and further discussions