Optimization Apparatus Escaping Local Minimums via Adaptive Offset

Resolve Bottlenecks,
Find Innovative Solutions
Generate Solutions

Solution Overview

Problem

Simulated annealing methods for discrete optimization problems face challenges in efficiently escaping local minimums, leading to prolonged calculation times due to slow temperature reduction and difficulty in making appropriate adjustments, which results in a low probability of reaching optimal solutions.

Innovation Solution

An optimization apparatus with a transition control unit that adds an offset to energy changes and prohibits state transitions back to previous states, using an offset control circuit to increase the offset at local minimums and reset it when a state transition occurs, thereby promoting escape from local minimums and reducing calculation time.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If simulated annealing is used to solve discrete optimization problems, then a solution can be found faster than precise algorithms, but the calculation time is prolonged due to slow escape from local minimums

Engineering Contradiction:
Improvespeed of finding solutionVSAvoidcalculation time
Core Design Contradiction:
ProductivityVSLoss of time

Solution Approach 1:

The offset control circuit performs preliminary action by proactively increasing the offset value before the system gets trapped in a local minimum. By detecting when no state transitions occur (indicating a local minimum), the circuit pre-increases the offset to facilitate future escape, rather than waiting passively for thermal excitation to occur naturally.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The invention dynamically changes the offset parameter based on the system's state. When the system is at a local minimum (no transitions occur), the offset is increased to modify the energy landscape and enable escape. This parameter adaptation allows the system to balance exploration and exploitation, reducing calculation time while maintaining solution quality.

Inventive Principle:
Principle #35Parameter changes

2Reliability

If temperature is reduced slowly to ensure proper annealing, then convergence is improved, but the duration spent at local minimums increases

Engineering Contradiction:
ImproveconvergenceVSAvoidduration at local minimums
Core Design Contradiction:
ReliabilityVSLoss of time

Solution Approach 1:

The offset control circuit introduces dynamics into the annealing process by making the offset value adaptive rather than static. The offset changes dynamically based on whether state transitions are occurring, allowing the system to accelerate through local minimums while maintaining proper convergence characteristics during normal operation.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The system uses feedback from the state transition process to control the offset. When no transitions occur (feedback indicating a local minimum), the offset is increased. This feedback mechanism allows the system to respond to its own behavior and adjust parameters in real-time to optimize both convergence and speed.

Inventive Principle:
Principle #23Feedback

3Loss of time

If the offset is increased to escape local minimums, then calculation time is reduced, but the system may overshoot optimal solutions

Engineering Contradiction:
Improvecalculation timeVSAvoidsolution accuracy
Core Design Contradiction:
Loss of timeVSMeasurement precision

Solution Approach 1:

The offset increase is applied locally and temporarily only when needed (at local minimums), rather than globally throughout the entire annealing process. This localized application of the offset ensures that accuracy is maintained during normal operation while enabling escape from local minimums when necessary.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The system serves itself by automatically detecting when it is trapped in a local minimum and self-correcting by increasing the offset. This self-service mechanism eliminates the need for external intervention or complex control logic, allowing the system to maintain accuracy while improving its own performance.

Inventive Principle:
Principle #25Self-service

Data Source

PatentUS10579763B2Optimization apparatus and method of controlling optimization apparatus
Publication Date: 2020.03.03 FUJITSU LTD
  • US10579763B2 patent drawing
  • US10579763B2 patent drawing
  • US10579763B2 patent drawing

AI summary

When stochastically deciding, based on a change in energy and a random number relating to thermal excitation, whether to accept any of a plurality of state transitions according to the relative relationship between the change in energy and thermal excitation energy, a transition control unit adds an offset to the change in energy, performs control so that the offset at a local minimum where energy is locally minimized is larger than an offset when the energy is not minimized, holds transition information (a transition number) indicating a previous state transition, and prohibits, based on a decoding result for the held transition information, a first state transition out of the present state transition candidates.