Key Points


  • Although DFTS is a design-focused quality technology, it also includes problem-solving/process-improvement capabilities and can benefit from the deployment of the Seven Basic (B7) Tools, widely used in manufacturing.

  • Additionally, techniques such as systems thinking, process management, standardization, and adequate documentation, which are integral parts of DFTS technology, must be integral parts of process improvement. These tools can be of great value in project management and in analyzing software metrics.

  • They can also be used in upstream design phases, except for statistical tools, which require larger volumes of data to be statistically significant. It is important to use them in the wider context of DFTS technology, which includes quality methodologies such as QFD, TRIZ, Pugh, Taguchi Methods, and FMEA.

  • A flowchart is a graphical, sequential representation of various activities. Identifying such activities and their causes can help you eliminate or minimize redundancies and wasteful activities as well as strengthen those that help achieve process goals and create customer value. A flowchart also serves as a communication tool.

  • Pareto charts are a series of bar charts with a cumulative line graph arranged in descending order. It indicates the diminishing importance of a series of activities or entities. It helps users focus on big issues. It can be used to address any concern that can be measured, such as cost, defects, faults, failures, complaints, returned items, repairs and fixes, risks, safety, and security.

  • Cause-and-effect diagrams are also called fishbone diagrams, for their structure, or Ishikawa diagrams, after their creator. Ishikawa diagrams include standard, process, and Pareto, to name a few. Cause-and-effect-diagrams are among the most widely used tools in quality management. They are used to identify causes of variation, to take countermeasures, for process classification, for Pareto-Ishikawa, to generate data needed for FMEA, to identify possible "noise" and "control factors" in Taguchi Methods, as a visible communication tool, and to categorize various inputs (causes) and output (effects).

  • A scatter diagram seeks to establish whether there is a relationship between two variables and the strength of that relationship. Establishing relationships can be particularly useful in cause-and-effect analysis. A strong correlation may help identify possible countermeasures to address a particular quality problem.

  • A check sheet is a paper form that lists items to be measured, checked, and recorded. It makes data collection easy, usable, and standardized. Various check sheets are possible, depending on the objective of the data collection exercisemeasuring process variation, analyzing types of defects, identifying causes of defects. A check sheet is often coupled with histograms to display visualization and use of data collected in histograms.

  • A histogram is used to analyze variation in a set of data. It helps you understand how the data collected from a particular development or production process is distributed in terms of frequency of occurrences of a particular value in the set. The key objective is to look for stability and predictability.

  • Graphs are useful tools in software quality and project management. Among the most commonly used graphs are run charts, pie charts, and bar charts. They help you monitor time variation and understand causes of defects in a process.

  • Control charts are among the most important quality tools. They have been used extensively in a variety of manufacturing industries as part of statistical process control (SPC). They measure a process's variation periodically to check whether it is within acceptable limits. Processes whose variation is within such limits are said to be "in control." "Out-of-control" processes lead to defective work, with adverse cost, quality, and schedule implications. SPC deploys control charts to prevent defective work from being produced by focusing efforts on the process quality rather than the final product. It thus lets the enterprise take preventive and process improvement initiatives rather than just appraising the final product. XmR charts and average (X-bar) and range (R) charts have been found to be most useful to measure the software process.

  • This chapter introduced B7 and some other process improvement tools in the software development context and is a precursor to Chapter 15.




Design for Trustworthy Software. Tools, Techniques, and Methodology of Developing Robust Software
Design for Trustworthy Software: Tools, Techniques, and Methodology of Developing Robust Software
ISBN: 0131872508
EAN: 2147483647
Year: 2006
Pages: 394

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