Tensor Train Restricted Boltzmann Machine for Image Data

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Solution Overview

Problem

Traditional Restricted Boltzmann machines (RBM) face challenges when dealing with multi-dimensional data due to exponential growth in parameters, leading to high computational complexity and storage needs, making them unsuitable for ordinary devices and multi-dimensional applications, and the process of vectorizing such data often destroys internal structures and association information.

Innovation Solution

The introduction of a TTRBM model with a tensor train format, where input and output data are represented as tensors, and the middle layer weights are restricted to a tensor train structure, allowing for adjustable rank to control the number of free parameters, reducing computational complexity and maintaining feature representation flexibility.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If traditional RBM is used with fully connected network structure, then feature representation ability is strong, but the number of parameters grows exponentially with data dimension, leading to high computational complexity and storage needs

Engineering Contradiction:
Improvefeature representation abilityVSAvoidnumber of parameters
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent segments the weight tensor into multiple mode-nets (mode-0 net, mode-1 net, etc.), where each mode-net corresponds to a specific dimension of the input data. This segmentation transforms the single fully connected layer into multiple specialized sub-networks, reducing the overall parameter count from exponential to linear growth with data dimension while maintaining feature representation capability.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent introduces a new dimensional structure by organizing weights as a multi-dimensional tensor rather than a traditional 2D weight matrix. The weight tensor has dimensions corresponding to different input features and mode-nets, creating a higher-order structure that enables more efficient parameterization and reduces the exponential parameter growth inherent in fully connected networks.

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

2Adaptability or versatility

If data is vectorized to apply RBM to multi-dimensional data, then RBM can process the data, but the internal structure of multi-dimensional data is destroyed, leading to loss of association information

Engineering Contradiction:
Improveapplicability to multi-dimensional dataVSAvoidassociation information
Core Design Contradiction:
Adaptability or versatilityVSLoss of information

Solution Approach 1:

Instead of flattening multi-dimensional data into vectors, the patent maintains the original multi-dimensional structure by introducing mode-nets that operate on different dimensions of the input tensor. Each mode-net processes a specific dimension while preserving the relationships within that dimension, thereby avoiding information loss while enabling RBM to handle multi-dimensional data effectively.

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

Solution Approach 2:

The patent applies different processing characteristics to different dimensions of the input data through mode-nets. Each mode-net is specialized for a particular dimension and can have different activation functions and weight structures, allowing the model to preserve local associations within each dimension while integrating information across dimensions.

Inventive Principle:
Principle #3Local quality

3Device complexity

If the number of free parameters is reduced using tensor train decomposition, then computational complexity and storage needs are reduced, but the flexibility of weight layer restriction decreases

Engineering Contradiction:
Improvecomputational complexityVSAvoidflexibility of weight layer
Core Design Contradiction:
Device complexityVSAdaptability or versatility

Solution Approach 1:

The patent makes the weight layer flexible and adaptive by allowing the number of mode-nets and their structures to be dynamically adjusted based on the specific application requirements. The mode-nets can be configured with different numbers of hidden units, different activation functions, and different connection patterns, enabling the model to adapt to various data types and tasks while maintaining reduced computational complexity through the structured tensor decomposition.

Inventive Principle:
Principle #15Dynamics

Data Source

PatentUS11449965B2Processing method for image tensor data
Publication Date: 2022.09.20 BEIJING UNIV OF TECH
  • US11449965B2 patent drawing
  • US11449965B2 patent drawing

AI summary

A processing method for image tensor data, which can greatly reduce the number of free parameters in the model, limit the weight layer flexibly, and can be applied to any order of image tensor data. In this processing method for image tensor data, TTRBM model of Restricted Boltzmann machine with tensor train format is introduced. The input and output data of this method are both represented by tensors, and the weight of the middle layer is also represented by tensors, and the restricted weight has the structure of tensor train. The number of free parameters in the middle layer is controlled by adjusting the rank of tensor train decomposition. The rank of TT decomposition is adjusted, and different feature representations with the same size are expressed.