• The Journal of the Acoustical Society of Korea
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• v.28 no.5
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• pp.461-470
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• 2009

We investigate and analyze the problems encountered in frame-based estimation of TDOA (Time Difference of Arrival) using CPSP function. Spectral leakage occurring in framing of a speech signal by a rectangular window could make estimation of CPSP spectrum inaccurate. Framing with other windows to reduce the spectral leakage distorts the signal due to the asynchronous weighting around the frame specifically both ends of the frame. These problems degrade the performance of the CPSP-based TDOA estimation. In this paper, we propose a method to alleviate those problems by pre-emphasis of the speech signal. It reduces the influence of the spectral leakage by reducing dynamic range of the spectrum of a speech signal with pre-emphasis. To validate the proposed method of pre-emphasis, we carry out TDOA estimation experiments in various noise and reverberation conditions, Experimental results have shown that the framing of pre-emphasized microphone output by a rectangular window achieves higher success rate of TDOA estimation than any other framing methods.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.8 no.1
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• pp.19-24
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• 2008

This paper presents a new JPEG quantization table design method for mobile images in handset. From the characteristics of the mobile images, we propose a modeling method of the quantization table and select the optimized pre-emphasis factor from various sets of $240{\times}320$ images. From the experiment, we show that the performance is improved in the sense of bpp and PSNR, applying the proposed method.

• Proceedings of the Acoustical Society of Korea Conference
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• spring
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• pp.171-174
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• 2002

음성신호는 성문특성으로 인해 고주파 특성이 약화되는 경향이 있다. 이를 보상하기 위해 Pre-emphasis filter를 사용한다. 수식으로 표현하면 y(n)=s(n)-As(n-1) 와 같이 차분방정식으로 나타낼 수 있다. 여기서 A값은 보통 0.9에서 1사이의 값을 주로 사용한다. 그러나 Pre-emphasis filter는 고주파 특성을 보상하는 과정에서 극점과 같이 영점도 왜곡된다. 본 논문에서는 음성특성에 따른 LSP(Line Spectrum Pairs) 분포특성을 이용하여 영점을 보존하고 vocoder 및 coding에 필연적인 고주파 특성 혹은 저주파 특성을 강조한다.

• Research in Mathematical Education
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• v.12 no.3
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• pp.215-233
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• 2008

Deep comprehension of basic mathematical notions and concepts is a basic condition of a successful teaching. Some elements of algebraic thinking belong to the elementary school mathematics. The question "What stays the same and what changes?" link arithmetic problems with algebraic conception of variable. We have studied beliefs and comprehensions of future elementary school mathematics teachers on early algebra. Pre-service teachers from three academic pedagogical colleges deal with mathematical problems from the pre-algebra point of view, with the emphasis on changes and invariants. The idea is that the intensive use of non-formal algebra may help learners to construct a better understanding of fundamental ideas of arithmetic on the strong basis of algebraic thinking. In this article the study concerning arithmetic series is described. Considerable number of pre-service teachers moved from formulas to deep comprehension of the subject. Additionally, there are indications of ability to apply the conception of change and invariance in other mathematical and didactical contexts.

• JSTS:Journal of Semiconductor Technology and Science
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• v.17 no.4
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• pp.552-560
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• 2017

This paper presents a transceiver chipset realized in a $0.13-{\mu}m$ CMOS technology for serial digital interface of video data transmission, which compensates the electrical cable loss of 45 dB in maximum at 1.5 Gbps. For the purpose, the TX equips pre-emphasis in the main driver by utilizing a D-FF with clocks generated from a wide-range tuning PLL. In RX, two-stage continuous-time linear equalizers and a limiting amplifier are exploited as a front-end followed by a 1/8-rate CDR to retime the data with inherent 1:8 demultiplexing function. Measured results demonstrate data recovery from 270 Mbps to 1.5 Gbps. The TX consumes 104 mW from 1.2/3.3-V supplies and occupies the area of $1.485mm^2$, whereas the RX dissipate 133 mW from a 1.2-V supply and occupies the area of $1.44mm^2$.

• Communications of Mathematical Education
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• v.33 no.2
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• pp.85-104
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• 2019

The purpose of this study is to analyze the tasks developed through task development activities with emphasis on mathematical connectivity, and to provide implications for teacher education to enhance teacher's competence. For this purpose, I analyzed the task developed by 52 pre-teachers through the activities. As a result, they combined mathematics with 'other subjects', 'mathematics', 'phenomenon', 'technology' and 'real life'. And they also made various internal connections of 'Different representation', 'Part-whole relationship', 'Implication', 'Procedure', and 'Instruction-oriented connection'. From the point of view of teacher knowledge, the study revealed that CCK and SCK were positive in terms of 'logical' and 'expression', and KCT as 'strategic' was meaningful but disappointing in diversity; however in terms of 'level', the KCS was limited due to tasks that did not meet the level of students. As such, this analysis reveals that teachers continue to struggle with understanding students' level, but exhibit little difficulty with 'logic', 'expression' and 'strategy. This being the case, teacher education needs to place additional emphasis in understanding students' levels and planning corresponding activities.

• English Language & Literature Teaching
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• v.12 no.1
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• pp.257-286
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• 2006

This paper investigates the effects of small group collaborative transcription activities on the improvement of university students' English listening ability. Based on the results of pre-tests, a class of 42 students was subdivided into 11 small homogeneous groups of three to four students. Each group was provided with 7 different news items to be transcribed. Means were compared between pre-test and post-test scores, followed by comparison of transcription errors in content and function words. Finally, students' perception and attitudes about the use of small group transcription for improving listening skills were qualitatively analysed and compared with pre- and post test results. It was found that post test scores highly correlated with improvement of listening ability. It was also found that groups of high degree of collaboration showed improvement in listening ability while lack of collaboration contributed to loss of interests in listening. Students who see process more important were found to make more contribution to the group success than those who place more emphasis on the results.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 1992.03a
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• pp.83-102
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• 1992

As shear localization is observed in different deformation modes, an attempt is made to understand the conditions for shear localization in general deformation modes. Most emphasis in put upon the effects of pre-localization deformation mode on the onset of shear localization and all the other well-recognized effects of subtle constitutive features and imperfection sensitivity studied elsewhere are not investigated here. Rather, an approximate perturbation stability analysis is performed for simplified isotropic rigid-plastic solids subjected to general mode of homogeneous deformation. Shear localization is possible in any deformation mode if the material has strain softening. The incipient rate of shear localization and shear plane orientations are strongly dependent upon the pre-localization deformation mode. Significant strain softening is necessary for shear localization in homogeneous axisymmetric deformation modes while infinitesimal strain softening is necessary for shear localization in plane strain deformation mode. In any deformation mode, there are more than one shear plane orientation. Except for homogeneous axisymmetric deformation modes, there are two possible shear plane orientations with respect to the principal directions of stretching. Some well-known examples are discussed in the light of the current analysis.

• Journal of the Korean Society of Clothing and Textiles
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• v.28 no.11
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• pp.1415-1425
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• 2004

The purpose of this study was to analyze a theoretical frame of expressional area, the characteristics and the effects which is applied to fashion illustration by metonymic theory. The theoretical frame of expressional area was analyzed by category analysis and 150 fashion illustrations from 1900 to 1999 were analyzed by contents analysis. The results of this study were as follows: The expressions of metonymy were categorized by close-up, realistic expression, omission, borrowing of past style, simplification and deconstruction. First, close-up was presented as emphasis of small part of fashion by cutting the scenes, snapshot, emphasis, etc. Second, realistic expression was presented as description of related circumstance with fashion message through perspective and realistic description of circumstance related to figures. Third, omission was presented as seeking of essential core by removing color, pattern, texture or by omitting body and as emphasis of communication about dominant fashion message. Fourth, borrowing of past style was presented as reminding us of background of the past. Fifth, simplification was presented as using of form or color to alleviate tension of object and to restore the essential reality. Sixth, deconstruction was presented as fragmenting of image, flattening of body and clothing, weakness of form, and strength of color. In conclusion, metonymy made by experience system of thinking based on the reality, have extended expressional territory in pre-existing fashion illustration. And these ways not only will provide fashion image as illustrator's subjective intention and theoretical system of expression of message, but also will be useful way to strengthen communication for easier interpretation of fashion illustration.

• The Journal of the Korea Contents Association
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• v.10 no.7
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• pp.31-39
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• 2010

In this study, we prepared the real environmental sound data sets arising from people's movement comprising 9 different environment types. The environmental sounds are pre-processed with pre-emphasis and Hamming window, then go into the classification experiments with the extracted features using MFCC (Mel-Frequency Cepstral Coefficients). The GMM (Gaussian Mixture Model) classifier without post processing tends to yield abruptly changing classification results since it does not consider the results of the neighboring frames. Hence we proposed the post processing methods which suppress abruptly changing classification results by taking the probability or the rank of the neighboring frames into account. According to the experimental results, the method using the probability of neighboring frames improve the recognition performance by more than 10% when compared with the method without post processing.