Scalable Multi-Task Learning via Convex Clustering

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Solution Overview

Problem

Current multi-task learning methods fail to efficiently learn multiple regression tasks with intrinsic correlations, leading to poor prediction performance, high training costs, and inability to scale with a large number of tasks, especially in scenarios like time series prediction where thousands of tasks are involved.

Innovation Solution

A scalable multi-task learning method using convex clustering that generates a graph of linear learning models, introduces auxiliary variables, and iteratively solves a sparse linear system to minimize a graph variable loss function, enabling efficient discovery and exploitation of task correlations while maintaining linear runtime scalability.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If traditional multi-task learning methods are used, then task correlations can be exploited to improve prediction performance, but the methods fail to scale efficiently with a large number of tasks and incur high training costs

Engineering Contradiction:
Improveprediction performanceVSAvoidtraining efficiency and scalability
Core Design Contradiction:
ReliabilityVSProductivity

Solution Approach 1:

The patent segments the multi-task learning problem by organizing tasks into clusters based on their correlations. Instead of treating all tasks uniformly, the method divides the task graph into convex clusters where tasks with similar patterns are grouped together. This segmentation enables the system to handle large numbers of tasks efficiently by processing them in manageable clusters rather than as a monolithic whole.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent introduces a graph-based representation that adds a structural dimension to the traditional task-list approach. By representing tasks as nodes in a graph with edges indicating correlations, and further organizing these into convex clusters, the method transforms the problem from a flat list of tasks to a hierarchical graph structure. This dimensional change enables more efficient computation and scaling while preserving task correlation information.

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

2Adaptability or versatility

If the number of tasks is increased to handle diverse prediction problems, then the system's adaptability improves, but the training time and computational cost increase significantly

Engineering Contradiction:
Improveability to handle diverse prediction problemsVSAvoidtraining time
Core Design Contradiction:
Adaptability or versatilityVSLoss of time

Solution Approach 1:

The patent segments tasks into convex clusters based on their correlation structures. This segmentation allows the system to maintain adaptability to diverse prediction problems while reducing training time by processing tasks in organized clusters rather than independently. The clustering structure enables efficient computation that scales with the number of tasks.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent employs dynamic graph construction where the task graph and its convex cluster decomposition are adapted based on the input data and task correlations. This dynamic approach allows the system to optimize its computational structure for each specific prediction problem, maintaining versatility while minimizing training time through adaptive graph-based organization.

Inventive Principle:
Principle #15Dynamics

Data Source

PatentUS11657322B2Method and system for scalable multi-task learning with convex clustering
Publication Date: 2023.05.23 NEC CORP
  • US11657322B2 patent drawing
  • US11657322B2 patent drawing
  • US11657322B2 patent drawing

AI summary

A method for scalable multi-task learning with convex clustering includes: extracting features from a dataset of a plurality of tasks; generating a graph from the extracted features, nodes of the graph representing linear learning models, each of the linear learning models being for one of the tasks; constraining the graph using convex clustering to generate a convex cluster constrained graph; and obtaining a global solution by minimizing a graph variable loss function, the minimizing the graph variable loss function comprising: introducing auxiliary variables for each connection between nodes in the convex cluster constrained graph; iteratively performing the following operations until convergence: updating the linear learning models by solving a sparse linear system; and updating the auxiliary variables by solving an equation having the auxiliary variables each be proportional to a vector norm for their respective nodes.