Hassan Sawaf

Hassan Sawaf
eBay Authors

Hassan Sawaf has close to 20 years of experience in research, development and management of Human Language Technology (HLT) and pattern recognition, in particular machine translation, speech recognition, image processing and language understanding.

From 1995 to 2010, he founded technology companies and led teams that cover science to product, covering aspects of science and technology over product management to executive of startup and mid-size companies. From November 2010 till January 2013, as a Chief Scientist he lead the research and development in machine learning and human language technology at SAIC. In March 2011 Hassan he was nominated Technical Fellow for his work in technology, and research and development management at SAIC. Since April 2013, Hassan joined eBay to setup, grow and lead the Cognitive Computing Group.


Language Independent Connectivity Strength Features for Phrase Pivot Statistical Machine Translation

An important challenge to statistical machine translation (SMT) is the lack of parallel data for many language pairs. One common solution is to pivot through a third language for which there exist parallel corpora with the source and target languages. Although pivoting is a robust technique, it introduces some low quality translations. In this paper, we present two language-independent features to improve the quality of phrase-pivot based SMT. The features, source connectivity strength and target connectivity strength reflect the quality of projected alignments between the source and target phrases in the pivot phrase table. We show positive results (0.6 BLEU points) on Persian-Arabic SMT as a case study.


Proceedings of the 6th International Joint Conference on Natural Language Processing

Selective Combination of Pivot and Direct Statistical Machine Translation Models

In this paper, we propose a selective combination approach of pivot and direct statistical machine translation (SMT) models to improve translation quality. We work with Persian-Arabic SMT as a case study. We show positive results (from 0.4 to 3.1 BLEU on different direct training corpus sizes) in addition to a large reduction of pivot translation model size.

Proceedings of the 2014 Conference on Empirical Methods in Natural Language Processing (EMNLP)

Correcting Keyboard Layout Errors and Homoglyphs in Queries

Keyboard layout errors and homoglyphs in cross-language queries impact our ability to correctly interpret user information needs and offer relevant results. We present a machine learning approach to correcting these errors, based largely on character-level n-gram features. We demonstrate superior performance over rule-based methods, as well as a significant reduction in the number of queries that yield null search results.

40th International Conference on Acoustics, Speech and Signal Processing (ICASSP) 2015

Switching to and Combining Offline-Adapted Cluster Acoustic Models based on Unsupervised Segment Classification

The performance of automatic speech recognition system degrades significantly when the incoming audio differs from training data. Maximum likelihood linear regression has been widely used for unsupervised adaptation, usually in a multiple-pass recognition process. Here we present a novel adaptation framework for which the offline, supervised, high-quality adaptation is applied to clustered channel/speaker conditions that are defined with automatic and manual clustering of the training data. Upon online recognition, each speech segment is classified into one of the training clusters in an unsupervised way, and the corresponding top acoustic models are used for recognition. Recognition lattice outputs are combined. Experiments are performed on the Wall Street Journal data, and a 37.5% relative reduction of Word Error Rate is reported. The proposed approach is also compared with a general speaker adaptive training approach.

Monday, October 26, 2009

Hybrid Machine Translation