Hierarchical Posterior Distribution Calculator for Fast Parameter Estimation

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Solution Overview

Problem

Existing methods for estimating parameter values in simulations with a large number of parameters require excessive time, leading to impractical computation times as the number of parameters increases exponentially, potentially preventing timely estimation.

Innovation Solution

A data calculation device and method utilizing hierarchical models, where a high-level model simulates a subject and low-level models simulate parts of the subject, allowing for the estimation of parameter values in a hierarchical structure, reducing the number of parameters in each model and facilitating faster computation by using high-level model outputs as inputs for low-level model simulations.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If parameter values are estimated using existing methods for simulations with a large number of parameters, then the estimation accuracy can be maintained, but the computation time increases exponentially

Engineering Contradiction:
Improveparameter value estimation accuracyVSAvoidcomputation time
Core Design Contradiction:
Measurement precisionVSLoss of time

Solution Approach 1:

The patent divides the simulation model into hierarchical levels (high-level model and low-level models). The high-level model estimates parameters for groups of subsystems, while low-level models estimate parameters for individual subsystems. This segmentation reduces the number of parameters estimated simultaneously, thereby reducing computation time while maintaining estimation accuracy through iterative refinement across levels.

Inventive Principle:
Principle #1Segmentation

2Adaptability or versatility

If the number of parameters for estimation is increased to cover a large-scale simulation subject, then the coverage and applicability improve, but the computation time becomes impractically long

Engineering Contradiction:
Improvesimulation coverageVSAvoidparameter estimation time
Core Design Contradiction:
Adaptability or versatilityVSLoss of time

Solution Approach 1:

The simulation subject is divided into multiple subsystems organized in a hierarchical structure. The high-level model handles parameters for multiple subsystems simultaneously, while low-level models handle individual subsystem parameters. This allows the system to maintain broad simulation coverage across large-scale subjects while keeping the computational burden manageable through the hierarchical division of parameter estimation tasks.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent introduces a hierarchical dimension to the parameter estimation process, organizing parameters into multiple levels (high-level and low-level). This dimensional organization allows the system to handle a large total number of parameters by distributing them across hierarchical levels, thereby maintaining simulation coverage while reducing the computational complexity at each estimation step.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

3Device complexity

If a single model is used to simulate the entire subject, then the model structure remains simple, but the number of parameters increases exponentially leading to long computation times

Engineering Contradiction:
Improvemodel structure complexityVSAvoidparameter estimation time
Core Design Contradiction:
Device complexityVSLoss of time

Solution Approach 1:

Instead of using a single model for the entire subject, the patent segments the model into a high-level model and multiple low-level models. The high-level model has a simpler parameter set that covers multiple subsystems, while low-level models have simpler individual parameter sets. This segmentation maintains overall model structure simplicity while reducing the exponential growth of parameters by distributing them across hierarchical levels.

Inventive Principle:
Principle #1Segmentation

Data Source

PatentUS20240028789A1Data calculation device, data calculation method, and recording medium
Publication Date: 2024.01.25 NEC CORP
  • US20240028789A1 patent drawing
  • US20240028789A1 patent drawing
  • US20240028789A1 patent drawing

AI summary

A data calculation device including a high-level posterior distribution data calculator for calculating data indicating a posterior distribution of parameter values of a high-level model that simulates a subject, based on target data for outputs from the high-level model; and a low-level posterior distribution data calculator for calculating, for a low-level model that simulates a portion of the subject and that outputs parameter values of the high-level model, data indicating a posterior distribution of parameter values of the low-level model, based on the data indicating a posterior distribution of parameter values of the high-level model.