ASSESSING LANGUAGE KNOWLEDGE IN JEJU: VOCABULARY AND VERBAL PATTERNS IN JEJUEO AND ENGLISH

Ph.D. Thesis. University of Hawaiʻi at Mānoa 2018

Toward a linguistically realistic assessment of language vitality: The case of Jejueo

The assessment of language endangerment requires accurate estimates of speaker populations, including information about the proficiency of different groups within those populations. Typically, this information is based on self-assessments, a methodology whose reliability is open to question. We outline an approach that seeks to improve the accuracy of self-assessment by exposing participants to a simple linguistic task before they render their judgments. The viability of the approach is evaluated with the help of a case study involving 81 partial speakers of Jejueo, a critically endangered Koreanic language.National Foreign Language Resource Cente

Early Seizure Detection by Applying Frequency-Based Algorithm Derived from the Principal Component Analysis

The use of automatic electrical stimulation in response to early seizure detection has been introduced as a new treatment for intractable epilepsy. For the effective application of this method as a successful treatment, improving the accuracy of the early seizure detection is crucial. In this paper, we proposed the application of a frequency-based algorithm derived from principal component analysis (PCA), and demonstrated improved efficacy for early seizure detection in a pilocarpine-induced epilepsy rat model. A total of 100 ictal electroencephalographs (EEG) during spontaneous recurrent seizures from 11 epileptic rats were finally included for the analysis. PCA was applied to the covariance matrix of a conventional EEG frequency band signal. Two PCA results were compared: one from the initial segment of seizures (5 sec of seizure onset) and the other from the whole segment of seizures. In order to compare the accuracy, we obtained the specific threshold satisfying the target performance from the training set, and compared the False Positive (FP), False Negative (FN), and Latency (Lat) of the PCA based feature derived from the initial segment of seizures to the other six features in the testing set. The PCA based feature derived from the initial segment of seizures performed significantly better than other features with a 1.40% FP, zero FN, and 0.14 s Lat. These results demonstrated that the proposed frequency-based feature from PCA that captures the characteristics of the initial phase of seizure was effective for early detection of seizures. Experiments with rat ictal EEGs showed an improved early seizure detection rate with PCA applied to the covariance of the initial 5 s segment of visual seizure onset instead of using the whole seizure segment or other conventional frequency bands

A Revised Analysis of the Tense-Aspect Markers in Jejueo, An Endangered Language of Korea

Jejueo pedagogical materials reflect previous misanalyses of the language’s verbal morphology. The current study proposes a new analysis of this morphology, noting that the traditional one was strongly influenced by syllable structure. I also discuss a revised system of tense and aspect that consists of three types of grammat.ical markers – perfective (-eos and -eon), continuative (-eoms), and non-past (-(eu)neun, and -eun), whose distribution is based on a new view of morpheme segmentation

Pre-Revitalization Language Assessment

Testing is increasingly recognized as a vital part of language revitalization. I demonstrate here that assessment of linguistic knowledge should also be part of the planning process that precedes the creation of a revitalization program. I take as an example Jejueo, the language of Korea’s Jeju Island. Whereas previously published work contradicted UNESCO’s conclusion that the language is critically endangered, a test that I designed to elicit basic vocabulary and verbal patterns from 224 participants (from elementary school students to senior citizens) revealed otherwise. Alarming deficits in basic knowledge of the language were uncovered that both confirmed UNESCO’s classification of the language and identified the particular areas in which remediation is required.National Foreign Language Resource Cente

Toward a linguistically realistic assessment of language vitality

The most widely used techniques for assessing language vitality (the Graded Intergenerational Disruption Scale, the UNESCO system, and the EL-CAT Language Endangerment Index) all derive their endangerment estimates from surveys that elicit self-reports of language proficiency and use. Unfortunately, speaker self-assessments can be distorted by a variety of factors, including confusion over what counts as proficiency in a language and a subconscious desire to understate or overstate one’s ability to use a community language that is cherished by some and criticized by others. We report here on a study that has the joint objective of (i) establishing that subjective self-assessments may often be inaccurate, and (ii) proposing a technique to reduce the effects of this problem. Participants: 61 residents of Korea’s Jeju Island, home to the critically endangered language Jejueo. The participants ranged in age from 20 – 29; all had Korean as their dominant language, but were proficient to varying degrees in Jejueo. Materials: Ten Jejueo sentences, constructed from items in the Swadesh list, were recorded by one male and one female speaker of Jejueo. Method: Participants heard each Jejueo sentence twice, first in the version produced by the male speaker, then in the version produced by the female speaker. In order to ensure attention to the meaning of the Jejueo test items, participants were asked to paraphrase each sentence in written Korean right after hearing it. Before beginning the task, participants were asked to estimate their comprehension ability in Jejueo on a scale of 1 (low) to 5 (high). At the conclusion of the task, they were asked to estimate their fluency a second time on the same scale. Results: Mean Self-Assessment of Proficiency Before and After Exposure to Jejueo Test Items Before After Mean difference 3.13 2.06 1.13 As these results show, participants produced noticeably lower self-assessments after being called upon to interpret actual Jejueo sentences. This pattern was observed in 38 of 61 participants; only three participants exhibited the reverse pattern of initially underestimating their abilities. These results suggest that traditional survey data, with its emphasis on self-assessment of language ability, may significantly overestimate proficiency levels, thereby providing an inaccurate and overly optimistic picture of language vitality. However, on a positive note, our findings suggest that this danger can be mitigated by embedding self-assessment surveys within tasks that involve exposure to the language being investigated

Poisson-Gaussian Noise Reduction Using the Hidden Markov Model in Contourlet Domain for Fluorescence Microscopy Images

<div><p>In certain image acquisitions processes, like in fluorescence microscopy or astronomy, only a limited number of photons can be collected due to various physical constraints. The resulting images suffer from signal dependent noise, which can be modeled as a Poisson distribution, and a low signal-to-noise ratio. However, the majority of research on noise reduction algorithms focuses on signal independent Gaussian noise. In this paper, we model noise as a combination of Poisson and Gaussian probability distributions to construct a more accurate model and adopt the contourlet transform which provides a sparse representation of the directional components in images. We also apply hidden Markov models with a framework that neatly describes the spatial and interscale dependencies which are the properties of transformation coefficients of natural images. In this paper, an effective denoising algorithm for Poisson-Gaussian noise is proposed using the contourlet transform, hidden Markov models and noise estimation in the transform domain. We supplement the algorithm by cycle spinning and Wiener filtering for further improvements. We finally show experimental results with simulations and fluorescence microscopy images which demonstrate the improved performance of the proposed approach.</p></div

The comparison of sparsity between wavelet and contourlet transforms on the <i>Lena</i> image.

<p>(a) wavelet, (b) contourlet.</p

Mapping materials property from atomic scale imaging with subpixel resolution

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The second set of HeLa cell images and denoising results.

<p>First low: the second set of HeLa cell images with different laser intensities. (a) 0.2, (b) 0.4, (c) 0.8. Second low: denoising results on HeLa cell image with laser intensity 0.4. (d) an average of 40 images used as the ground truth, (e) BM3D, (f) the proposed method.</p