Time-Based Decay for Knowledge Base Rating Accuracy

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Solution Overview

Problem

Existing ranking systems for web sites, forums, and knowledge bases equally weight all user ratings over time, leading to outdated rankings that do not accurately reflect the current value or quality of elements, as older ratings remain equally significant as newer ones.

Innovation Solution

Implementing a time-based weighting system that discounts older ratings and biases the cumulative rating towards more recent ratings, using formulas such as exponentially weighted moving averages to ensure that newer ratings have greater influence in determining the overall ranking.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If all ratings are averaged equally to determine overall ranking, then historical data is preserved and sample size is maximized, but the ranking becomes outdated and less accurate over time

Engineering Contradiction:
Improveranking accuracyVSAvoidhistorical rating data
Core Design Contradiction:
Measurement precisionVSLoss of information

Solution Approach 1:

The patent applies dynamics by making the weighting factors time-dependent and variable rather than static. The weighting factor for each rating is determined by its age, with newer ratings receiving higher weights and older ratings receiving lower weights. This dynamic adjustment allows the system to adapt to changing information value over time, resolving the contradiction between preserving historical data and maintaining current accuracy.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent changes the parameter of rating weight from a constant value to a time-varying parameter. By introducing a weighting factor that decreases with the age of the rating, the system transforms the calculation from a simple average to a weighted average that accounts for temporal decay in information value. This parameter change enables the system to maintain accuracy while still incorporating historical data with appropriate diminishing influence.

Inventive Principle:
Principle #35Parameter changes

2Adaptability or versatility

If older ratings are given equal weight to newer ratings, then all user feedback is valued equally, but the cumulative rating does not reflect current element quality

Engineering Contradiction:
Improveresponsiveness to current qualityVSAvoidtotal rating data utilized
Core Design Contradiction:
Adaptability or versatilityVSQuantity of substance

Solution Approach 1:

The system dynamically adjusts the influence of each rating based on its temporal distance from the present. Newer ratings have a stronger impact on the cumulative rating, while older ratings have progressively less impact. This dynamic weighting mechanism allows the system to remain responsive to current quality while still incorporating a comprehensive body of historical feedback data.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

By changing the weighting parameter from uniform to time-decay based, the system achieves adaptability to current quality conditions. The weighted average calculation with time-based factors ensures that the cumulative rating reflects present element quality while utilizing the full quantity of available rating data, with each rating's contribution appropriately scaled by its age.

Inventive Principle:
Principle #35Parameter changes

3Measurement precision

If information on a web site becomes time-sensitive and less valuable over time, then newer ratings should carry more weight, but implementing time-based weighting complicates the ranking system

Engineering Contradiction:
Improvecurrent value representationVSAvoidranking calculation complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent implements time-based weighting by changing the parameter from simple averaging to weighted averaging with time-dependent factors. While this does increase calculation complexity, the use of systematic weighting formulas (such as exponential or linear decay) provides a structured approach that balances precision in representing current value with manageable computational complexity. The complexity is justified by the significant improvement in ranking accuracy.

Inventive Principle:
Principle #35Parameter changes

Data Source

PatentUS8719203B2Method and apparatus for time-based decay of knowledge base ratings
Publication Date: 2014.05.06 CISCO TECHNOLOGY INC
  • US8719203B2 patent drawing
  • US8719203B2 patent drawing
  • US8719203B2 patent drawing

AI summary

In one embodiment, a method includes obtaining a plurality of ratings associated with an element, where the plurality of ratings includes at least a first rating and a second rating. The method also includes applying a first weighting factor to the first rating and applying a second weighting factor to the second rating. The first weighting factor is different from the second weighting factor. Finally, the method includes determining a cumulative rating using the first weighting factor, the second weighting factor, and the plurality of ratings. The cumulative rating is associated with the element and the second weighting factor is arranged to discount the second rating.