Probabilistic Tree Transducer Training via Weighted Forests

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Solution Overview

Problem

Current tree transducers require complex training processes and lack efficient methods for learning from sample input/output pairs, particularly in statistical language processing tasks like machine translation and paraphrasing, where automated linguistic operations are cumbersome and inefficient.

Innovation Solution

The development of techniques to train probabilistic R transducers using tree/string pairs and weighted regular tree grammars, which simplify the training process by converting input/output trees into derivation forests and employing memoization and expectation maximization to optimize transducer parameters, facilitating efficient linguistic operations such as machine translation and text compression.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If traditional tree transducers are used for linguistic operations, then language processing tasks can be performed, but the training process becomes complex and inefficient

Engineering Contradiction:
Improvelanguage processing efficiencyVSAvoidtraining process complexity
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

The patent replaces manual, mechanical training processes with automated probabilistic learning mechanisms. Tree transducers are trained using expectation maximization algorithms that automatically learn from corpus data, substituting the complex manual configuration process with an automated statistical learning system that handles parameter optimization independently.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The invention introduces probabilistic parameters to tree transducer productions, transforming deterministic rules into probabilistic ones. This allows the system to learn optimal parameter values from training data through expectation maximization, changing the fundamental nature of transducer operations from fixed-rule-based to adaptive probability-based transformations.

Inventive Principle:
Principle #35Parameter changes

2Speed

If automated linguistic operations are implemented, then processing speed improves, but accuracy and linguistic knowledge distillation become challenging

Engineering Contradiction:
Improveprocessing speedVSAvoidlinguistic knowledge accuracy
Core Design Contradiction:
SpeedVSMeasurement precision

Solution Approach 1:

The patent implements expectation maximization as a feedback mechanism where the transducer parameters are iteratively refined based on performance measurements from training corpora. The algorithm computes expected counts from current parameters, maximizes likelihood based on these counts, and repeats the process, creating a closed-loop system that continuously improves accuracy through measured performance feedback.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The system performs preliminary training actions on corpora before actual language processing tasks. By pre-training the transducer parameters on representative training data, the system prepares optimized linguistic knowledge in advance, enabling both high speed during actual processing and high accuracy through pre-learned linguistic patterns.

Inventive Principle:
Principle #10Preliminary action

Data Source

PatentUS7698125B2Training tree transducers for probabilistic operations
Publication Date: 2010.04.13 UNIV OF SOUTHERN CALIFORNIA
  • US7698125B2 patent drawing
  • US7698125B2 patent drawing
  • US7698125B2 patent drawing

AI summary

Tree transducers can be trained for use in probabilistic operations such as those involved in statistical based language processing. Given sample input/output pairs as training, and given a set of tree transducer rules, the information is combined to yield locally optimal weights for those rules. This combination is carried out by building a weighted derivation forest for each input/output pair and applying counting methods to those forests.