This paper describes a language-independent model for fully unsupervised morphological analysis that exploits a universal framework leveraging morphological typology.By modeling morphological processes including suffixation, prefixation, infixation, and full and partial reduplication with constrained stem change rules, our system effectively constrains the search space and offers a wide coverage in terms of morphological typology.The system is tested on nine typologically and genetically diverse languages, and shows superior performance over leading systems.We also investigate the effect of an oracle that provides only a handful of bits per language to signal morphological type.

This paper describes an unsupervised model for morphological segmentation that exploits the notion of paradigms, which are sets of morphological categories (e.g., suffixes) that can be applied to a homogeneous set of words (e.g., nouns or verbs). Our algorithm identifies statistically reliable paradigms from the morphological segmentation result of a probabilistic model, and chooses reliable suffixes from them. The new suffixes can be fed back iteratively to improve the accuracy of the probabilistic model. Finally, the unreliable paradigms are subjected to pruning to eliminate unreliable morphological relations between words. The paradigm-based algorithm significantly improves segmentation accuracy. Our method achieves start-of-the-art results on experiments using the Morpho-Challenge data, including English, Turkish, and Finnish.

This paper argues that developmental patterns in child language be taken seriously in computational models of language acquisition, and proposes a formal theory that meets this criterion. We first present developmental facts that are problematic for statistical learning approaches which assume no prior knowledge of grammar, and for traditional learnability models which assume the learner moves from one UG-defined grammar to another. In contrast, we view language acquisition as a population of grammars associated with "weights", that compete in a Darwinian selectionist process. Selection is made possible by the variational properties of individual grammars; specifically, their differential compatibility with the primary linguistic data in the environment. In addition to a convergence proof, we present empirical evidence in child language development, that a learner is best modeled as multiple grammars in co-existence and competition.

A new approach to software reliability estimation is presented that combines operational testing with stratified sampling in order to reduce the number of program executions that must be checked manually for conformance to requirements. Automatic cluster analysis is applied to execution profiles in order to stratify captured operational executions. Experimental results are reported that suggest this approach can significantly reduce the cost of estimating reliability.

We present a new approach to reducing the manual labor required to estimate software reliability. It combines the ideas of partition testing methods with those of stratified sampling to reduce the sample size necessary to estimate reliability with a given degree of precision. Program executions are stratified by using automatic cluster analysis to group those with similar features. We describe the conditions under which stratification is effective for estimating software reliability, and we present preliminary experimental results suggesting that our approach may work well in practice.