462 research outputs found
Sound change in Functional Phonology
No full textSound systems may never stop changing, not even if only internal factors are present, because there may always be a better system. Non-teleological random variation of constraint ranking defines a pressure that explains the existence of perpetually rotating cycles of sound changes.The definitive version of this article was published in Functional Phonology: Formalizing the Interactions Between Articulatory and Perceptual Drives (1998) and is available at http://www.fon.hum.uva.nl/paul/Boersma, P. (1997). Sound change. In Functional phonology: Formalizing the interactions between articulatory and perceptual drives (pp. 381-414). The Hague: Holland Academic Graphics.ISBN: 9789055690541 (Published book
Spreading in functional phonology
No full textThe occurrence of and the restrictions on the temporal spreading of phonological feature values (assimilation, harmony) are the results of interactions between the functional principles of minimizing articulatory effort and minimizing perceptual confusion. This proposal is tested on the typology of opacity to nasal spreading. While the sonority approach of Gnanadesikan (1995) meets with insuperable problems with regard to the position of /h/ in the hierarchy, and the feature-geometric representational approach of Piggott (1992) needs to take recourse to ad-hoc conditions in UG in order to get the hierarchy right, the functional approach accurately predicts the attested typology.The definitive version of this article was published in Functional Phonology: Formalizing the Interactions Between Articulatory and Perceptual Drives (1998) and is available at http://www.fon.hum.uva.nl/paul/Boersma, P. (1997). Spreading. In Functional phonology: Formalizing the interactions between articulatory and perceptual drives (pp. 441-460). The Hague: Holland Academic Graphics.ISBN: 9789055690541 (Published book
Comparing Two Optimality-Theoretic Learning Algorithms for Latin Stress
No full textThis paper compares the performance of two formal Optimality-Theoretic learning algorithms in modelling the acquisition of Latin stress from overt language data: Error-Driven Constraint Demotion (EDCD; Tesar 1995) and the Gradual Learning Algorithm (GLA; Boersma 1997). We present computer simulations of learners who are trained on several kinds of overt Latin stress patterns: a case with main stress only, three cases with overtly available secondary stress, and a case in which the learners are free to invent their own secondary stress patterns. Several of these cases turn out to be learnable with the GLA, none with EDCD.The definitive version of this paper was published in WCCFL 23: Proceedings of the 23rd West Coast Conference on Formal Linguistics (2004) and is available at http://www.cascadilla.com/wccfl23.htmlISBN: 9781574730739 (Conference publication
Transient energy growth modulation by temperature dependent transport properties in a stratified plane Poiseuille flow
No full textWe investigate the effect of temperature dependent thermal conductivity λ and isobaric specific heat c_P on the transient amplification of perturbations in a thermally stratified laminar plane Poiseuille flow. It is shown that for decreasing thermal conductivity the maximum transient energy growth is amplified with respect to the λ=1 case, while the opposite occurs for increasing λ. A reversed mechanism is induced by a variable c_p. Substantial maximum growth enhancement/suppression is found in the range of Prandtl numbers Pr which encompasses most fluids of practical interest. The relative growth modulation shows an optimum Pr under spanwise perturbations. For energy amplifying property distributions a speed-up of the transient to reach the maximum energy growth is observed at low Pr, while a slow-down is found at large Pr. The opposite is true when the property variations suppress the growth of perturbations
Review of Case Studies for Quantitative Reasoning: A Casebook of Media Articles by Bernard L. Madison, Stuart Boersma, Caren L. Diefenderfer, and Shannon W. Dingman
No full textBernard L. Madison, Stuart Boersma, Caren L. Diefenderfer, and Shannon W. Dingman. Case Studies for Quantitative Reasoning: A Casebook of Media Articles (Pearson Learning Solutions, 2012). 215 pp. ISBN 9781256512875.
Concisely organized and timely to a tee, Case Studies for Quantitative Reasoning contains a wealth of articles and exercises to promote higher-order thinking in any course where quantitative literacy is a goal. The text is a self-contained package complete with just enough mathematics to ensure that all students can join in. It contains a total of twenty-four case studies, each of which highlights how numbers appear in day-to-day media. The text is broken into six broad mathematical topics, each of which includes any background mathematics necessary for reading. Each individual study includes warm-up exercises and follow-up questions that demand critical thinking. Notwithstanding the elementary mathematics prerequisite to read the text, the topics and questions are sufficiently challenging to keep a class – and accompanying instructor – engaged for an entire semester
Learning OT constraint rankings using a maximum entropy model
No full textA weakness of standard Optimality Theory is its inability to account for grammars with free variation. We describe here the Maximum Entropy model, a general statistical model, and show how it can be applied in a constraint-based linguistic framework to model and learn grammars with free variation, as well as categorical grammars. We report the results of using the MaxEnt model for learning two different grammars: one with variation, and one without. Our results are as good as those of a previous probabilistic version of OT, the Gradual Learning Algorithm (Boersma, 1997), and we argue that our model is more general and mathematically well-motivated
Modelling the perceptual development of phonological contrasts with OT and the Gradual Learning Algorithm
No full textOne of the tasks of the language acquisition process is to optimize strategies for comprehension. For speech perception, this means that the learner has to establish an accurate mapping from acoustically detailed input to discrete phonological categories. As an example, this paper considers the development of the perception of the English vowels /I/ and /i/ in native speakers.
Production-wise, the two vowels differ in various respects. Here, we limit ourselves to considering duration and the first formant (F1). It turns out that the use of these two acoustic dimensions in production depends on the dialect at hand: for Scottish English speakers, /I/ and /i/ differ much more in F1 and much less in duration than for Southern English speakers.
We hypothesize that humans have an optimal perception strategy that minimizes the probability of confusion and that there is a knowledge that underlies the implementation of this strategy. We model the knowledge behind speech perception as an Optimality-Theoretic perception grammar, and we model the acquisition of this knowledge with the Gradual Learning Algorithm. Using an environment based on real production data, we simulate the development of a Scottish and a Southern English listener, and show that the Scot comes to rely almost exclusively on height (F1) when distinguishing /I/ and /i/, whereas the Southerner comes to rely on both height and duration, so the model indeed implements an optimal strategy for acoustic cue integration. Perception experiments show that real Scots and real Southerners also use this optimal strategy in their own environments.
We find, therefore, that perceptual strategies depend on the production environment, and that we can successfully model this dependency within the framework of stochastic Optimality Theory, thus bringing speech-processing systems within the reach of formal phonological theory.The definitive version of this paper was published in Proceedings of the 25th Annual Penn Linguistics Colloquium (2003) and is available at http://ling.upenn.edu/papers/v8.1-contents.htmlEscudero, P., & Boersma, P. (2003). Modelling the Perceptual Development of Phonological Contrasts with Optimality Theory and the Gradual Learning Algorithm. In S. Arunachalam, E. Kaiser & A. Williams (Eds.), Proceedings of the 25th Annual Penn Linguistics Colloquium. Philadelphia, Pa: Univ. of Pennsylvania.Peer reviewe
Effect of viscosity and density gradients on turbulent channel flows
No full textWe perform Direct Numerical Simulations (DNS) of a turbulent channel flow with temperature dependent density and viscosity. The Navier-Stokes equations are solved using their low Mach number formulation. In the simulations performed, the fluid is internally heated and the temperature at the walls is fixed. The friction Reynolds number based on half channel height and wall friction velocity is Reτ = 395. The modulation of turbulence, which is caused by the density and viscosity gradients, is characterized using the semi-local scaling of Huang et al. [1995, JFM]
Loanword adaptation as first-language phonological perception
No full textWe show that loanword adaptation can be understood entirely in terms of phonological and phonetic comprehension and production mechanisms in the first language. We provide explicit accounts of several loanword adaptation phenomena (in Korean) in terms of an Optimality-Theoretic grammar model with the same three levels of representation that are needed to describe L1 phonology: the underlying form, the phonological surface form, and the auditory-phonetic form. The model is bidirectional, i.e., the same constraints and rankings are used by the listener and by the speaker. These constraints and rankings are the same for L1 processing and loanword adaptation
Complete examples of encryption systems broken by Elizebeth Smith Friedman: 1923–1934
No full textElizebeth Smith Friedman has been credited with breaking hundreds of encryption systems during Prohibition, yet few complete examples exist. Using material available in the Elizebeth Smith Friedman archives at the Marshall Library, examples of a variety of encryption systems are presented. Complete examples include original ciphertext, plaintext, and a description of the encryption process. Friedman’s cryptanalysis of some of these messages is described
- …
