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D

decoupling buffer

→ see buffer

defect

An output that does not conform to a condition of satisfaction or specification; not to standard; not of quality.

One of 7 wastes defined by Ohno (1988) referring to effort needed to address incorrect information, rework, and scrap.

defined, definition [LPS]

In the Last Planner System, a quality criterion for assignments that questions whether or not assignments are specific enough so that the right type and amount of information and materials can be collected, work can be coordinated with other disciplines or trades, and it is possible to tell at the end of an agreed-upon time period (e.g., a planning week) if the assignment has been completed. Assignments are ‘well defined’ when those who are to execute the assignment understand what work is to be done, where and when it is to be done, and can determine what materials and information is needed in order to do the work. When possible, assignments should be so defined that it is possible at the conclusion of the plan period to tell by looking if they were performed.

demand leveling, heijunka, production leveling

→ see load leveling

Deming Cycle

→ see PDCA

Named after W. Edwards Deming (1900-1993) and based on work of Walter A. Shewhart (1891-1967).

dependence, interdependence

Defining a relationship between two or more activities, concepts, or things.

  1. Sequential dependence: one preceding the other, e.g., predecessor-successor relationship between activities where the first must be completed before the second can start.
  2. Reciprocal dependence: Where two or more activities are related so that one cannot be started (or finished) without a certain measure of progress or completion having been achieved by the other.
  3. Shared resource dependence: Where two or more activities require the same resource during their execution, e.g., two activities sharing a crane.

design

A type of goal-directed, reductive (not deductive) reasoning. There are always many possible designs, especially if one is willing to relax constraints (requirements). Product design reasons from function to form. Process design reasons from ends to means.

design criteria

The characteristics required for acceptance of product or process design.

Example: The structural engineer needs both geometric and load inputs from the architect, mechanical engineer, and electrical engineer. Loads need only be accurate within 20%.

directive

Instruction or order issued by a Last Planner to direct workers (or production units) on what to do and possibly when or how to do it. Directives may apply to selection of prerequisites, resources, process execution, or criteria for output evaluation.

→ related to Activity Definition Model