Genetic Algorithm Search Method with Lifespan and State Transitions

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Solution Overview

Problem

Existing search methods, such as neural networks and genetic algorithms, often get trapped in local minimum solutions and struggle to adapt to time-series changes in problem characteristics, leading to inefficiencies and the need for reinitialization when dealing with new problems.

Innovation Solution

A genetic algorithm-based search method that includes selection, mutation, and crossover operations for candidate solutions, where individuals have a lifespan and can transition between living and dead states, allowing for diversity and adaptation to changing problem characteristics without requiring reinitialization.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Speed

If neural network steepest descent method is used, then search speed is improved, but the method converges to local minimum and cannot reach optimum solution

Engineering Contradiction:
Improvesearch speedVSAvoidsolution optimality
Core Design Contradiction:
SpeedVSReliability

Solution Approach 1:

The patent combines the speed advantage of gradient-based methods with the global search capability of genetic algorithms by integrating fitness evaluation with gradient information. The modified fitness function incorporates both the objective function value and gradient magnitude, allowing the algorithm to quickly approach optimal regions while avoiding local minima through genetic variation mechanisms.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The patent implements feedback mechanisms through fitness sharing and elitism strategies. The fitness sharing approach provides feedback about the search space structure by penalizing regions with similar solutions, while elitism preserves the best solutions across generations, ensuring that the search process continuously improves while maintaining diversity to escape local minima.

Inventive Principle:
Principle #23Feedback

2Reliability

If general genetic algorithm is used, then global search capability is improved, but convergence to specific species occurs and diversity is lost

Engineering Contradiction:
Improveglobal search capabilityVSAvoidsolution diversity
Core Design Contradiction:
ReliabilityVSAdaptability or versatility

Solution Approach 1:

The patent applies local quality through fitness sharing and niche techniques. By evaluating fitness not only based on objective function value but also on similarity to other solutions, the algorithm creates different selective pressures for different regions of the search space. This maintains diversity by allowing multiple species to coexist in different niches rather than converging to a single optimal solution.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The patent implements dynamic adaptation through changing population composition over time. The algorithm dynamically adjusts which individuals are selected for reproduction based on real-time fitness evaluations and environmental conditions. This dynamic process allows the population to adapt to changing problem landscapes and maintain diversity by continuously evolving new solution types.

Inventive Principle:
Principle #15Dynamics

3Reliability

If general genetic algorithm is used, then problem solving capability is improved, but reinitialization is required when problem characteristics change

Engineering Contradiction:
Improveproblem solving capabilityVSAvoidreinitialization time
Core Design Contradiction:
ReliabilityVSLoss of time

Solution Approach 1:

The patent applies preliminary action by pre-establishing a diverse population with multiple species before the actual problem solving begins. This initial diversity is maintained through careful selection of initial individuals and use of mutation operators that preserve genetic variation. When problem characteristics change, this pre-established diversity allows the algorithm to quickly adapt without requiring complete reinitialization.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent implements parameter changes through dynamic adjustment of genetic algorithm parameters such as mutation rate, crossover probability, and population size. These parameters are modified based on the problem characteristics and search progress, allowing the algorithm to adapt to changing problem conditions. This dynamic parameter adjustment enables the algorithm to handle time-varying problems without reinitialization.

Inventive Principle:
Principle #35Parameter changes

4Reliability

If genetic operation is performed on all individuals, then search thoroughness is improved, but computational cost increases

Engineering Contradiction:
Improvesearch thoroughnessVSAvoidcomputational cost
Core Design Contradiction:
ReliabilityVSUse of energy by moving object

Solution Approach 1:

The patent applies partial action by selecting only a subset of individuals for genetic operations rather than processing the entire population. Through fitness-based selection, the algorithm identifies the most promising individuals and applies genetic operations selectively to them. This partial approach maintains search thoroughness by focusing computational resources on the most relevant regions of the search space while reducing overall computational cost.

Inventive Principle:
Principle #16Partial or excessive action

Data Source

PatentUS9323890B2Optimal solution search method and optimal solution search device
Publication Date: 2016.04.26 HAYASHI NAOKI
  • US9323890B2 patent drawing
  • US9323890B2 patent drawing
  • US9323890B2 patent drawing

AI summary

A search device and method of a pertinent solution using a genetic algorithm that performs genetic operation(s) on a plurality of individuals each having an element of a candidate solution to a problem in the form of a gene sequence. Genetic information about target individuals includes whether all individuals are, regardless of their fitness values, in a state among a living state that is a target of genetic operation and a target of calculating a fitness value, and a dead state that is not the target of genetic operation nor the target of the calculation of the fitness value. Each target individual has a predetermined value of a lifespan. A breeding area that allows predation of leading an individual belonging to a lower layer to a dead state due to predation by an individual belonging to a higher layer in the breeding area is an aspect of generating new target individuals.