• Journal of Korean Society for Geospatial Information Science
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• v.21 no.4
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• pp.109-116
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• 2013

To extract the 3D geometric information from SAR(Synthetic Aperture Radar) images, two different techniques, interferometric SAR and radargrammetry, have been widely used. InSAR is most widely used for the generation of precise DEM(Digital Elevation Model) until now. But, Interferometric SAR requires severe temporal correlation over areas covered with vegetation and high relief areas. Because radargrammetry is less sensible to temporal correlation, it can provide better results than interferometric SAR in certain, especially X-band SAR. In this paper, we assess the properties of DEMs generated by radargrammetry using stereo C-band RADARSAT-1 images and X-band TerraSAR-X images.

• Journal of the Korean Society of Safety
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• v.25 no.3
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• pp.123-130
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• 2010

Electroencephalogram(EEG) would be the most objective psychophysiological research technique on human errors though few research has been taken yet. This study aimed to get characteristics of human error while committing simple Odd-Ball tasks by utilizing the power spectrum technique of EEG data. Each experiment was composed of 3 tasks with different rules, and 8 young undergraduate students participated in this study as paid subjects. The result showed in the affirmative that subject and the interaction of subject and task factors were statistically significant on variation of $\alpha$ band power $P_{\alpha/(\alpha+\beta+\theta)}$ and $\beta$ band power $P_{\beta/(\alpha+\beta+\theta)}$, and that the former increasing in backward direction to Pz reflects compatibility whereas the latter increasing in forward direction to Fz reflects familiarity. Therefore it was coucluded that, since task 2 carried out in the present research requiring decoding process would be more difficult to human beings than the task merely requiring psychological recall process, task 1 and task 3 were classified into a homogenious group excluding task 2, and the ratio $\alpha$ band power to $\beta$ band power indicated enormous increase of $\alpha$ band power relative to $\beta$ band power in the cases of contra-lateral errors, especially in task 2.

• Journal of Korean Society for Geospatial Information Science
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• v.22 no.4
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• pp.117-125
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• 2014

Korea's first X-band SAR satellite KOMPSAT-5 has been launched in 2013, so the research related to the X-band SAR satellite image is required to increase the utilization of KOMPSAT-5. In this study, we generated a DEM(Digital Elevation Model) using X-band SAR satellite images based on three methods which are InSAR, radargrammetry and RPC(Rational Polynomial Coefficients), and evaluated the performance of each methods. The four stripmap mode TerraSAR-X images taken in Daejeon were used to generate DEM, and accuracy was evaluated using DEM by IKONOS RPC. As results, DEM produced by the InSAR showed the highest accuracy. Also, we knew that RPC could be effective method if you want to create a large area DEM which contains the various elevation.

• The Journal of the Acoustical Society of Korea
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• v.21 no.6
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• pp.552-558
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• 2002

Recently, based on the human speech recognition (HSR) model of Fletcher, the multi-band speech recognition has been intensively studied by many researchers. As a new automatic speech recognition (ASR) technique, the multi-band speech recognition splits the frequency domain into several sub-bands and recognizes each sub-band independently. The likelihood scores of sub-bands are weighted according to reliabilities of sub-bands and re-combined to make a final decision. This approach is known to be robust under noisy environments. When the noise is stationary a sub-band SNR can be estimated using the noise information in non-speech interval. However, if the noise is non-stationary it is not feasible to obtain the sub-band SNR. This paper proposes the inverse sub-band distance (ISD) weighting, where a distance of each sub-band is calculated by a stochastic matching of input feature vectors and hidden Markov models. The inverse distance is used as a sub-band weight. Experiments on 1500∼1800㎐ band-limited white noise and classical guitar sound revealed that the proposed method could represent the sub-band reliability effectively and improve the performance under both stationary and non-stationary band-limited noise environments.

• The Journal of the Acoustical Society of Korea
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• v.23 no.6
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• pp.481-487
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• 2004

In this paper. the structure of bandwidth scalable wideband speech codec and its high-band codec are proposed. In the high-band codec. the signal is divided into frequency bands. and each band is quantized in DCT domain. The DCT coefficients are splitted into magnitude and sign, and each is quantized independently by a specialized method based on its characteristics. In addition. the quantized gain parameter in the low-band codec is utilized in the high-band codec for an enhanced performance. The bandwidth scalable wideband speech codec using G.729E for low-band and the proposed codec for high-band is developed, and it is confirmed that the proposed codec has better subjective performance than 24kbps G.722.1.

• The Journal of Natural Sciences
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• v.8 no.2
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• pp.147-152
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• 1996

The 2,4-D + BA combination in MS medium showed high regenerating ability and induced compact callus from leaf and petiole segments of three strawberry cultivars, 'Bokyo', 'Suhong', whereas the NAA + BA combination resulted in friable callus. Band of RAPD products obtained with primer 212 from the callus was different from the band of mother plant when callus induced from leaf segment of 'Suhong' cultivar was maintained in MS medium containing NAA or BA for 8 months. The RAPD bands obtained from mother plants of 'Bokyo' and 'Yeobong' were different from that of callus maintained in the presence of MS liquid medium containing 2,4-D(0.2 mg/$\ell$) subcultured every two weeks for 6 months(12 subcultures).

• The Transactions of The Korean Institute of Electrical Engineers
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• v.61 no.1
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• pp.104-109
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• 2012

In this paper, we propose a way to improve the quality of L-band wireless communication from unfriendly influential factors lying in the neighboring RF bands. The UHF-band system has resonator components and they generate harmonics as the spurious in the L-band. Therefore, a metamaterial CRLH bandpass filter is designed for the purpose of system miniaturization and smaller insertion loss, and its spurious phenomenon is observed in the frequency domain. And its harmonics in the L-band are suppressed by a compact bandstop filter whose equivalent circuit is newly developed. The design methodology is validated by the equivalent circuit to be compared with commercial full-wave EM software simulations, where the spurious is dropped by 20dB. Also, the advantage of the proposed design is presented by the comparison where our filter is much smaller than the conventional parallel edge coupled filter by over 50%, with excellent harmonic suppression.

• Physical Therapy Rehabilitation Science
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• v.12 no.3
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• pp.355-364
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• 2023

Objective: The aim of this study is to test the effects of elastic band exercise accompanied by Swiss ball exercise on lower limb muscle strength, balance and pain in middle-aged women with osteoarthritis. Design: A randomized controlled trial. Methods: Thirty-five participants were randomly assigned to the experimental group (n=18), which performed elastic band exercise combined with Swiss ball exercise, and the control group (n=17), which performed elastic band exercise only. Both groups did a 30-minute session of exercise three times a week for eight weeks and were assessed for lower extremity muscle strength, static and dynamic balance, and pain levels before the first therapy session. All participating patients underwent outcome assessment after eight weeks of therapy without any additional treatment. Results: The experimental group made a significant increase in muscle strength of the lower extremities, static and dynamic balance ability, and pain level (p<0.05). The control group made a significant improvement in lower limb muscle strength, dynamic balance ability and pain level (p<0.05) with no such improvement in static balance ability. The exercise group made a significant increase in static and dynamic balance ability and pain level compared to the control group (p<0.05). Conclusions: These results demonstrated that both Swiss ball exercise and elastic band exercise were effective for middle-aged women with osteoarthritis and found that elastic band exercise combined with Swiss ball exercise produced more significant effects on their balance and pain.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.31 no.6
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• pp.485-492
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• 2019

The observation system has been developed to investigate the rip currents at Haeundae beach using X-band marine radar. X-band radar system can observe shape, size, and velocity of rip currents, which is difficult to obtain through field observation by conventional device. Algorithms which automatically detect locations, shapes, and magnitudes of rip currents were developed using time averaged X-band radar sea clutter images. X-band sea clutter images are transformed through 3D FFT into 2D wave number spectrum and frequency spectrum. Rip current velocities were estimated using differences in wave-number spectra and wave frequency spectra due to Doppler shift. The algorithm was verified by drift experiments. At Haeundae beach, the radar system exactly located the rip currents and found to be sustained for 1-2 days at fixed locations.

• JSTS:Journal of Semiconductor Technology and Science
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• v.6 no.3
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• pp.175-181
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• 2006

Wide band-gap semiconductor electron devices have made great progresses to produce very high power amplifiers for various wireless standards. The advantages of wide band-gap electronic devices and their progresses are summarized in this paper.