Deploying a Poka Yoke System

Preventing human

Designing components with unique signatures: This is done by errors carefully documenting software components or library programs so that the user knows what he is getting. The Java language has a capability called introspection that allows the using program to ask an object what it does and how it does it, to prevent such errors.

Using linking procedures that respect signatures: The program can be given preambles that will prevent them from being misused, and objects can hide data and protect methods so that using programs cannot change or modify them in error.

Use of error flags: Signaling an error condition by an error flag or exception so that an error handler can prevent transaction failure or database corruption.

Root cause analysis and corrective measures required before work resumes: This is done in business applications by careful input editing and rejection of suspicious transactions to an exception file that is examined by a human expert, corrected, and reprocessed later.

Warning about sources of defects

Component labeling and documentation: Documenting, classifying, and labeling software components.

Determinate component hierarchies: Object hierarchies and object interfaces like Java uses.

Flagging hierarchy violations: Java can do this if the object class is properly specified.

Designing preventive mechanisms

Eliminating error-prone components: Use well- tested computer Library programs or classes or components.

Amplification of human senses: Robotic and neural net programming technology.

Redundancy in design (backup systems): Coding several versions of an algorithm to handle a variety of data input.

Simplification by using fewer components: This is a major goal of program design; it is called reusability.

Enhancing product producibility and maintainability: Design programs so that they are lucid, easily understood , and easily maintained and modified, typically by programmers much less experienced than the original authors.

Selecting components that are proven: This is a very important aspect of reusable programs and is one of the main goals of object-oriented programming.

Bug-prevention mechanisms

" Next operation as customer": All programmers thoroughly test their own work.

Test prior work before adding any more value: Don't add anything to a program that has not been tested and may have faults. Test early and frequently.

Install programmer's command: Real-time check or "automatic program correction."

Use object-oriented programming: This helps avoid errors.

Get rid of defect-prone software: If a software unit exceeds an error threshold, throw it out and let a different developer do the recoding. Early errors predict late errors. Statistical sampling can predict how many faults are left, but it cannot locate them.

(The preceding steps cannot eliminate bugs , but they leave fewer and less complicated errors.)

Preventive inspections

Source inspection: To check process errors and correct them at the source.

Self-check inspection: Self-check by the software developer and fixing the product before handing it over.

Successive check methods: Checks by the next person in the process and correcting problems before proceeding.