• The Journal of the Acoustical Society of Korea
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• v.16 no.2
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• pp.49-57
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• 1997

In this paper, we propose the stochastic pronunciation lexicon model for large vocabulary continuous speech recognition system. We can regard stochastic lexicon as HMM. This HMM is a stochastic finite state automata consisting of a Markov chain of subword states and each subword state in the baseform has a probability distribution of subword units. In this method, an acoustic representation of a word can be derived automatically from sample sentence utterances and subword unit models. Additionally, the stochastic lexicon is further optimized to the subword model and recognizer. From the experimental result on 3000 word continuous speech recognition, the proposed method reduces word error rate by 23.6% and sentence error rate by 10% compare to methods based on standard phonetic representations of words.

• Journal of Korean Institute of Industrial Engineers
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• v.18 no.1
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• pp.25-36
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• 1992

A possible adverse effect on the likelihood of front-seat occupant fatalities from unbelted rear-seat occupants in frontal crashes is investigated using Fatal Accident Reporting System data. Passenger cars which sustained frontal damage and which did not roll over are included in this analysis. Of the frontally damaged cars, only cars containing a driver and a right-front passenger are selected. Then, from these cars, the following three cases are considered: a) left-rear occupant present, b) right-rear occupant present, and c) no one else in the car. Cars belonging to a) or b) contain only three occupants, and those belonging to the last case contain only two occupants. In addition, all occupants are unbelted. To estimate the influence of rear-seat occupants on front-seat occupant fatalities, relative risks of driver and right-front passenger fatalities are compared pairwise across these three cases. The adverse influence of unbelted rear-seat occupants on the likelihood of unbelted front-seat occupant fatalities in frontal crashes is estimated to be 7.9% ${\pm}$ 45%(the error limits indicate one standard error). In other words, front-seat occupant fatalities are increased 7.9% in frontal crashes due to the loadings from unbelted rear-seat occupants. This suggests that the usage of safety belts by rear-seat occupants not only may extend their own lives but also helps in reducing the fatalities of front-seat occupants seated in front of them.

• Nuclear Engineering and Technology
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• v.49 no.5
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• pp.1063-1070
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• 2017

This paper presents a method for forecasting future uranium prices that is used as input data to calculate the uranium cost, which is a rational key cost driver of the nuclear fuel cycle cost. In other words, the statistical autoregressive integrated moving average (ARIMA) model and existing engineering cost estimation method, the so-called escalation rate model, were subjected to a comparative analysis. When the uranium price was forecasted in 2015, the margin of error of the ARIMA model forecasting was calculated and found to be 5.4%, whereas the escalation rate model was found to have a margin of error of 7.32%. Thus, it was verified that the ARIMA model is more suitable than the escalation rate model at decreasing uncertainty in nuclear fuel cycle cost calculation.

• The Journal of the Acoustical Society of Korea
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• v.27 no.8
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• pp.443-449
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• 2008

One of the key issues in practical speech processing is to achieve robust Voice Activity Deteciton (VAD) against the background noise. Most of the statistical model-based approaches have tried to employ equally weighted likelihood ratios (LRs), which, however, deviates from the real observation. Furthermore voice activities in the adjacent frames have strong correlation. In other words, the current frame is highly correlated with previous frame. In this paper, we propose the effective VAD approach based on a minimum classification error (MCE) method which is different from the previous works in that different weights are assigned to both the likelihood ratio on the current frame and the decision statistics of the previous frame.

• The Journal of the Korea Contents Association
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• v.9 no.12
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• pp.459-466
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• 2009

While Korean allows the same consonants at the coda of the preceding syllable and at the onset of the following syllable, English does not allow the geminate consonants in the same intervocalic position. Due to this difference between Korean and English, Korean learners of English tend to incorrectly produce geminate consonants for English geminate graphemes as in $su\underline{mm}er$. Based on this observation, a pilot study was designed to investigate how Korean learners of English perceive and produce English doubleton graphemes and singleton graphemes. Twenty Korean college students were asked to perform a forced-choice perception test as well as a production test for the 36 real word stimuli which consist of (near) minimal pairs of singleton and doubleton graphemes. The result showed that the accuracy rates for the words with singleton graphemes were higher than those for the words with doubleton graphemes both in perception and production because the subjects misperceived and misproduced the doubleton graphemes as geminates due to orthographic influence. In addition, the low error rates of the word with voiced stops were accounted for by Korean language transfer. Further, spectrographic analyses were provided where more production errors were witnessed in doubleton grapheme words than singleton grapheme words. Finally, pedagogical implications are provided.

• Korean Journal of Cognitive Science
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• v.26 no.1
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• pp.27-51
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• 2015

The present study tested the effect of a top-down influence on recalling the colors of Stroop words. Participants remembered the colors of 1, 2, 3 or 6 Stroop words. After 1 second of a memory delay, they were asked to recall the color of a cued Stroop word by selecting out its corresponding color on a color-wheel stimulus. The correct recall was defined when the participants chose a color that was within ${\pm}45^{\circ}$ from the exact location of Stroop word's color on the color-wheel. Otherwise, the recall was defined as incorrect. The analyses of the frequency distribution of the participants' responses in the error trials showed that the probability of choosing the color-name of the target Stroop word was higher than the probability of other five color-names on the color-wheel. Further analyses showed that increasing the number of Stroop words to manipulate memory load did not affect the probability of the Stroop interference. These results indicate that the top-down interference by Stroop manipulation may induce systematic distortion of the stored representation in visual working memory.

• Journal of the Institute of Electronics Engineers of Korea SP
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• v.42 no.3 s.303
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• pp.91-98
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• 2005

In this paper, we propose a temporal error concealment method based on the edge adaptive masking. In the method, four regions around the corrupted block - top, bottom, left, and right - are defined and the edge features of the regions are extracted by applying an edge operator for each direction. The size of a mask for the boundary matching is determined by the edge information, which can be considered as a criterion to measure the activity of the boundary region. In other words, it is determined such that the size of the mask is proportional to the amount of edge-component extracted from each region in order to yield the higher reliability on boundary matching. This process is equivalent to applying weights depending on the edge features, which leads the improved motion vector. In experiments, it is verified that the proposed method outperforms the conventional methods in terms of image quality, and then its merits and demerits are discussed.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.18 no.10
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• pp.1495-1507
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• 1993

In this paper, an implementation of RS (Reed-Solomon) code decoder for CDP (Compact Disc Player) using microprogramming method is presented. In this decoding strategy, the equations composed of Newton's identities are used for computing the coefficients of the error locator polynomial and for checking the number of erasures in C2(outer code). Also, in C2 decoding the values of erasures are computed from syndromes and the results of C1(inner code) decoding. We pulled up the error correctability by correcting 4 erasures or less. The decoder contains an arithmetic logic unit over GF(28) for error correcting and a decoding controller with programming ROM, and also microinstructions. Microinstructions are used for an implementation of a decoding algorithm for RS code. As a result, it can be easily modified for upgrade or other applications by changing the programming ROM only. The decoder is implemented by the Logic Level Modeling of Verilog HDL. In the decoder, each microinstruction has 14 bits( = 1 word), and the size of the programming ROM is 360 words. The number of the maximum clock-cycle for decoding both C1 and C2 is 424.

• 유체기계공업학회:학술대회논문집
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• 2000.12a
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• pp.265-271
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• 2000

Orifice meters and turbine meters are frequently used for measuring gas flow in gas industry. However, to insure the accuracy of the measurement, a certain length of the meter run at the upstream of the flow meter is required. The objective of this study is to analyze flow measurement errors of the orifice meter quantitatively for shorter lengths of the meter runs than those suggested in the standard manuals with variation of diameter ratio( $\beta$ ratio) and flow rate and also to analyze flow measurement errors of the turbine meter with and without straightener. The test results showed that the flow measurement errors of the orifice meter were inversely proportional to the diameter ratio. In other words, when the diameter ratio is 0.3 and 0.7, the measurement error is $-7.3\%$ and $-3.5\%$, respectively. the main reason of the measurement error is due to the swirl effect from the configuration of the meter run at the upstream of the flow meter. In case the length of the meter run is shorter than that suggested In the standard, the swirl effect is not removed completely and it affects the flow meter's performance. As mentioned above, the less the pipe diameter ratio, the mon the flow measurement error. It means that the swirl effect on the orifice meter increases as the $\beta$ ratio decreases.

• Journal of the Korean Institute of Intelligent Systems
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• v.14 no.1
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• pp.28-32
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• 2004

Till now, Korean spelling proofreading system has corrected words of a sentence from the relationship of a collocation or the grammatical information of the sentence. In this paper, we propose a system that corrects a word using the relationship among the sememes in a single sentence and substitutes an apt word for a word of the sentence that has the meaningful mistake by a mistyping. The proposed system makes several sentences that are able to communicate with each sememe. The substantives forms meaning tree according to the meaning of the word and the predicate of a sentence defines the meaningful relationship between a substantives of the subject and the object. After this system compares and analyzes the relationship of meaning, it corrects the mistyping of a word in a single sentence that includes an error. If the system finds out the semantic error by the mistyping, it applies the spelling proofreading method that proposed in this paper.