Demand Distribution Classification for Safety Stock Planning

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Solution Overview

Problem

Current safety stock planning in supply chain management systems is overly simplistic, failing to accurately characterize demand data, particularly distinguishing between regular and sporadic demand, and not accounting for differences in historical and planning periods.

Innovation Solution

A system and method that evaluates historical demand characteristics such as mean value, standard deviation, and fraction of periods without demand to categorize demand as regular or sporadic, selecting appropriate mathematical models (Gaussian or Gamma distributions) for safety stock calculations, and adjusting parameters to match planning periods.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If a simple variation coefficient threshold (0.5) is used to distinguish regular and sporadic demand, then the classification process is simple and quick, but the accuracy of demand characterization deteriorates

Engineering Contradiction:
Improvesimplicity of demand classificationVSAvoidaccuracy of demand characterization
Core Design Contradiction:
Ease of operationVSMeasurement precision

Solution Approach 1:

The patent transforms the single-parameter classification (variation coefficient only) into a multi-parameter evaluation system incorporating mean demand, standard deviation, and multiple time period analyses. This changes the classification parameters from simple to comprehensive, resolving the contradiction between simplicity and accuracy by making the classification process more informative without being overly complex.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent segments the demand classification process into distinct evaluation stages: calculating variation coefficient, calculating mean demand, calculating standard deviation, and analyzing multiple time periods. This segmentation allows each parameter to be evaluated independently and systematically, improving accuracy while maintaining operational clarity through structured analysis.

Inventive Principle:
Principle #1Segmentation

2Device complexity

If historical demand data is used directly without period adjustment, then the calculation process is simple, but the accuracy of safety stock planning deteriorates due to period length mismatches

Engineering Contradiction:
Improvesimplicity of calculation processVSAvoidaccuracy of safety stock planning
Core Design Contradiction:
Device complexityVSMeasurement precision

Solution Approach 1:

The patent applies preliminary period adjustment to historical demand data before performing safety stock calculations. By pre-adjusting the variation coefficient and other parameters to match the planning period length, the system eliminates period mismatch errors in advance, resolving the contradiction between calculation simplicity and planning accuracy.

Inventive Principle:
Principle #10Preliminary action

3Device complexity

If only variation coefficient is considered for demand classification, then the classification method is simple, but the reliability of safety stock planning deteriorates due to insufficient demand characteristics analysis

Engineering Contradiction:
Improvesimplicity of classification methodVSAvoidreliability of safety stock planning
Core Design Contradiction:
Device complexityVSReliability

Solution Approach 1:

The patent creates a composite classification approach that combines multiple demand characteristics (variation coefficient, mean demand, standard deviation, and period-specific metrics) into a unified demand classification system. This composite methodology reliably distinguishes between regular and sporadic demand by synthesizing multiple indicators, resolving the contradiction between method simplicity and planning reliability.

Inventive Principle:
Principle #40Composite materials

Data Source

PatentUS8200521B2System and method for determining demand distribution for safety stock planning
Publication Date: 2012.06.12 SAP SE
  • US8200521B2 patent drawing
  • US8200521B2 patent drawing
  • US8200521B2 patent drawing

AI summary

A system and method are described for identifying an appropriate demand distribution to use for safety stock planning within a supply chain management (“SCM”) system. For example, one embodiment of the invention comprises a computer-implemented method comprising: extracting historical demand characteristics for a product from a specified data source, the demand characteristics including the mean value of the demand for specified periods of time and/or the fraction of periods without any demand; evaluating the historical demand characteristics including the mean value of the demand for the specified periods and/or the fraction of periods without any demand; based on the evaluation, categorizing the demand characteristics into one of two or more different predefined categories; and using the classification to perform safety stock calculations for the product over the specified periods of time.