• Proceedings of the Korean Information Science Society Conference
• /
• 2006.06b
• /
• pp.34-36
• /
• 2006

In this paper we present a method of feature extraction for motor imagery single trial EEG classification, where we exploit nonnegative matrix factorization (NMF) to select discriminative features in the time-frequency representation of EEG. Experimental results with motor Imagery EEG data in BCI competition 2003. show that the method indeed finds meaningful EEG features automatically, while some existing methods should undergo cross-validation to find them.

• The Korean Journal of Ecology
• /
• v.17 no.3
• /
• pp.379-385
• /
• 1994

Sonograms of songs recorded in Kwangnung and Chejudo were analyzed to investigate the features and variances in the songs of Great tit, Parus major variety. Songs of Great tits were identified, most of which were repetitions of phrases compoed of high-frequency note and low-frequency note. Variances between the songs of the two areas in the minimum and maximum of low-frequency were significat. The CV range of the Great tit group in Chejudo was wider than that in Kwangnung. Interregional variance level was significant in the minimum (P<0.04) and maximum (P<0.0001) of low-frequency.

• Transactions of the Korean Society of Machine Tool Engineers
• /
• v.10 no.3
• /
• pp.26-30
• /
• 2001

Controller refinement scheme to improve the performance of a conventional system automatically in frequency domain is proposed. The controller automatic tuning method features using experimental frequency responses of the conventional closed-loop system, the conventional controller, and the improved closed-loop system, instead of poorly modeled plant due to non-linearities and disturbances. The improved closed-loop system characteristics is automatically acquired by the con-ventional closed-loop system characteristics and the proposed performance index in system bandwidth. And the proper controller is realized by least squares approximation in frequency domain. To testify the usefulness of the approach, the path tracking control of robot arm is performed. Experimental results and analytic results are well-matched.

• Proceedings of the Korean Society of Precision Engineering Conference
• /
• 2000.11a
• /
• pp.136-139
• /
• 2000

Controller refinement scheme to improve the performance of a conventional system automatically in frequency domain is proposed. The controller automatic tuning method features using experimental frequency responses of the conventional closed-loop system, the conventional controller, and the improved closed-Imp system; instead of poorly modeled plant due to non-linearities and disturbances. The improved closed-loop system characteristics is automatically acquired by the conventional closed-loop system characteristics and the proposed performance index in system bandwidth. And the proper controller is realized by least squares approximation in frequency domain. To testify the usefulness of the approach, experimental results of robot path-tracking control applied with various controllers is used, and then is analyzed with respect to a equivalent proportional controller. Experimental results and analytic results are well-matched.

• Phonetics and Speech Sciences
• /
• v.6 no.4
• /
• pp.133-139
• /
• 2014

This paper describes several approaches to transform a speaker's individuality to another's individuality using frequency warping between bilingual formant frequencies on different language environments. The proposed methods are simple and intuitive voice conversion algorithms that do not use training data between different languages. The approaches find the warping function from source speaker's frequency to target speaker's frequency on formant space. The formant space comprises four representative monophthongs for each language. The warping functions can be represented by piecewise linear equations, inverse matrix. The used features are pure frequency components including magnitudes, phases, and line spectral frequencies (LSF). The experiments show that the LSF-based voice conversion methods give better performance than other methods.

• The Transactions of The Korean Institute of Electrical Engineers
• /
• v.58 no.5
• /
• pp.1047-1049
• /
• 2009

This paper presents an intelligent electronic device(IED) platform which is based on a new frequency estimation algorithm. The IED platform features not only the accurate estimation of frequency but also the fast network-based transmisstion of fault data and waveforms. The simulation results show that the proposed frequency estimation algorithm improves convergence speed, and has lower frequency estimation error compared with those of conventional algorithms. The network-based IED is designed to ensure transmission latency being less than 1.0% of sampling interval.

• The Transactions of The Korean Institute of Electrical Engineers
• /
• v.63 no.7
• /
• pp.934-939
• /
• 2014

The daily recording of basal body temperature is the most useful method of determining the term of ovulation by resolving the rise in temperature. To support this aim, Graphical User Interface (GUI) system is designed and implemented to visualize the basal body temperature variations on daily basis by using android platform smartphone with programming multi-thread Java modules. To estimate the occurrence of ovulation cycle, a new method of analyzing the low-frequency features including a DC level and the second largest peak in frequency spectrum domain is proposed with interpreting the prominent features into the average basal-body temperature variations and a menstrual cycle.

• Journal of the Korean Data and Information Science Society
• /
• v.25 no.4
• /
• pp.819-828
• /
• 2014

In this paper, we analyze the characteristics of the English vocalization of deaf students and present the basic data for the development of personalized English learning aid tools that reflect its features. We visited hearing special schools in Seoul and Daegu and recorded English vocalization of the deaf students in order to analyze the characteristics of deaf students' English vocalization. We analyzed the data by Praat program, an professional voice analysis program. The voice features of deaf students' English vocalization were extracted and then compared with those of non-deaf students' English vocalization.

• Proceedings of the IEEK Conference
• /
• 2002.07c
• /
• pp.1531-1534
• /
• 2002

Shape description and its corresponding matching algorithm is one of the main concerns in MPEG-7. In this paper, a new method is proposed for shape registration of 2D objects for MPEG-7 Shapes are recognized using the Hu statistical moments in frequency domain. The Hu moments are moment-based descriptors of planar shapes, which are invariant under general translation, rotational, scaling, and reflection transformation. The image is transformed into frequency domain using Fourier Transform. Annular and radial wedge distributions fur the power spectra are extracted. Different statistical features (Hu moments) are found f3r the power spectrum of each selected transformed individual feature. The Euclidean distance of the extracted moment descriptors of the features are found with respect to the shapes in the database. The minimum Euclidean distance is the candidate for the matched shape. The simulation results are performed on the test shapes of MPEG-7.

• IEMEK Journal of Embedded Systems and Applications
• /
• v.3 no.1
• /
• pp.8-18
• /
• 2008

In this paper, we propose an efficient algorithm using wavelet transform for still image database retrieval. Especially, it uses only the lowest frequency sub-band in multi-level wavelet transform so that a retrieval system uses a smaller quantity of memory and takes a faster processing time. We extract different textured features, statistical information such as mean, variance and histogram, from low frequency sub-band. Then we measure the distances between the query image and the images in a database in terms of these features. To obtain good retrieval performance, we use the first feature (mean and variance of wavelet coefficients) to filter out most of the unlikely images. The rest of the images are considered to be candidate images. Then we apply the second feature (histogram of wavelet coefficient) to rank all the candidate images. To evaluate the algorithm, we create various distorted image databases using MIT VisTex texture images and PICS natural images. Through simulations, we demonstrate that our method can achieve performance satisfactorily in terms of the retrieval accuracy as well as the both memory requirement and computational complexity. Therefore it is expected to provide good retrieval solution for JPEG-2000 using wavelet transform.