• 한국항공운항학회:학술대회논문집
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• 2005.11a
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• pp.112-119
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• 2005

• Proceedings of the Korea Water Resources Association Conference
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• 2001.05a
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• pp.152-157
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• 2001

No Abstract (See Full-text)

• BMB Reports
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• v.42 no.11
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• pp.752-757
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• 2009

Copper is essential but toxic in excess for aerobic organisms. Yeast transcription factor ACE1 functions as a sensor for copper and an inducer for the transcription of CUP1. In addition, ACE1 can activate the transcription of superoxide dismutase gene (sod1) in response to copper. In this study, we introduced the yeast ACE1 into Arabidopsis and analyzed its function in plant. Under high copper stress, the transgenic plants over-expressing ACE1 showed higher survival rate than the wild-type. We also found that over-expression of ACE1 in Arabidopsis increased the activities of SOD and POD, which were beneficial to the cell in copper buffering. Excess copper would suppress the expression of chlorophyll biosynthetic genes in Arabidopsis, RT-PCR analysis revealed that over-expression of ACE1 decrease the suppression. Together, our results indicate that ACE1 may play an important role in response to copper stress in Arabidopsis.

• Asian Journal of Atmospheric Environment
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• v.5 no.1
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• pp.47-55
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• 2011

Variations in ambient atmospheric carbon monoxide(CO) observed at an inland mining site in the Indo-Gangetic plains, Jaduguda ($22^{\circ}38'N$, $86^{\circ}21'E$, 122m MSL, ~75 km away from the coast of the Bay of Bengal) during the Tsunami of 26 December 2004 were monitored. CO mixing ratio over this site was measured using a non-dispersive infrared analyzer (Monitor Europe Model 9830 B). Back trajectory analysis data obtained using NOAA Hybrid Single Particle Lagrangian Integrated Trajectory (HYSPLIT) Model was also used for this study. Variations in CO mixing ratio at a coastal site, Thiruvananthapuram ($8^{\circ}29'N$, $76^{\circ}57'E$, located ~2 km from the Arabian Sea coast) have also been investigated using CO data retrieved from the Measurement Of Pollution In The Troposphere (MOPITT) instrument. Ground-based measurements indicated abnormal variations in CO mixing ratio at Jaduguda from 25 December 2004 evening (previous day of the Tsunami). MOPITT CO data showed an enhancement in CO mixing ratio over Thiruvananthapuram on the Tsunami day. Back trajectory analyses over Thiruvananthapuram and Jaduguda for a period of 10 days from $21^{st}$ to $30^{th}$ December 2004 depicted that there were unusual vertical movements of air from high altitudes from 25 December 2004 evening. CO as well as the back trajectory analyses data showed that the variations in the wind regimes and consequently wind driven transport are the most probable reasons for the enhancement in CO observed at Jaduguda and Thiruvananthapuram during the Tsunami.

• ETRI Journal
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• v.32 no.2
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• pp.281-291
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• 2010

Scalable video coding (SVC) has been standardized as an extension of the H.264/AVC standard. This paper proposes a practical real-time transport protocol (RTP) packetization scheme to transport SVC video over IP networks. In combined scalability of SVC, a coded picture of a base or scalable enhancement layer is produced as one or more video layers consisting of network abstraction layer (NAL) units. The SVC NAL unit header contains a (DID, TID, QID) field to identify the association of each SVC NAL unit with its scalable enhancement layer without parsing the payload part of the SVC NAL unit. In this paper, we utilize the (DID, TID, QID) information to derive hierarchical spatio-temporal relationship of the SVC NAL units. Based on the derivation using the (DID, TID, QID) field, we propose a practical RTP packetization scheme for generating single RTP sessions in unicast and multicast transport of SVC video. The experimental results indicate that the proposed packetization scheme can be efficiently applied to transport SVC video over IP networks with little induced delay, jitter, and computational load.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.8 no.3
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• pp.517-522
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• 2004

In this paper, we have analyzed the performance enhancement of Orthogonal Frequency Division Multiplexing/Quadrature Phase Shift Keying Modulation-Digital Microwave Radio(OFDM/QPSK-DMR) system using Band Limited-Pulse Shaping Filter(BL-PSF) over microwave channel environments. For performance enhancement, the one-tap adaptive equalizer is adopted in the OFDM/QPSK-DMR system and than both BER and signature curve performance are compared with those of single carrier DMR system. Computer simulations confirm that the OFDM/QPSK-DMR system using 16 sub-carrier increase the fade margin about 2 dB over microwave channel environments and that of performance using one-tap adaptive equalizer is highly increased the fade margin as the number of sub-carriers is larger.

• Journal of Broadcast Engineering
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• v.22 no.5
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• pp.608-617
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• 2017

Methods of contrast enhancement have problem such as side effect of over-enhancement with non-gaussian histogram distribution, tradeoff enhancement efficiency against brightness preserving. In order to enhance contrast at various histogram distribution, segmentation to region with gaussian distribution and then enhance contrast each region. First, we segment an image into several regions using GMM(Gaussian Mixture Model)fitting by that k-mean clustering and EM(Expectation-Maximization) in $L^*a^*b^*$ color space. As a result region segmentation, we get the region map and probability map. Then we apply local contrast enhancement algorithm that mean shift to minimum overlapping of each region and preserve brightness histogram equalization. Experiment result show that proposed region based contrast enhancement method compare to the conventional method as AMBE(AbsoluteMean Brightness Error) and AE(Average Entropy), brightness is maintained and represented detail information.

• Korean Journal of Cognitive Science
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• v.25 no.1
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• pp.51-71
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• 2014

This paper presents an image enhancement method in real road traffic scenes. The images captured by the camera on the car cannot keep the color constancy as illumination or weather changes. In the real environment, these problems are more worse at back light conditions and at night that make more difficult to the applications of the vision-based intelligent vehicles. Using the existing image enhancement methods without considering the position and intensity of the light source and their geometric relations the image quality can even be deteriorated. Thus, this paper presents a fast and effective method for image enhancement resembling human cognitive system which consists of 1) image preprocessing, 2) color-contrast evaluation, 3) alpha blending of over/under estimated image and preprocessed image. An input image is first preprocessed by gamma correction, and then enhanced by an Automatic Color Enhancement(ACE) method. Finally, the preprocessed image and the ACE image are blended to improve image visibility. The proposed method shows drastically enhanced results visually, and improves the performance in traffic sign detection of the vision based intelligent vehicle applications.

• Atmosphere
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• v.32 no.4
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• pp.341-351
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• 2022

Recently, interest in the possibility of a washout effect using artificial rain enhancement technology to reduce high-concentration fine dust is growing. Therefore, in this study, the reduction rate of PM₁₀ concentration according to the amount of artificial rain enhancement was calculated during Asian Dust event which occurred over the Korean Peninsula on March 29, 2021 using air quality model [i.e., Community Multiscale Air Quality (CMAQ)] combined with the mesoscale model for artificial rain enhancement (i.e., WRF-MMS). According to WRF-MMS, the washout effect lasted 5 hours, and the maximum precipitation rate was calculated to be 1.5 mm hr^-1. According the CMAQ results, the PM₁₀ reduction rate was up to 22%, and the affected area was calculated to be 6.4 times greater than that of the artificial rain enhancement area. Even if the maximum amount of precipitation per hour is lowered to 0.8 mm hr^-1 (about 50% level), the PM₁₀ reduction rate appears to be up to 16%. In other words, it is believed that this technique can be used as a direct method for reducing high-concentration fine dust even when the artificial rain enhancement effect is weak.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2008.05a
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• pp.784-788
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• 2008

In this research, we propose a remote speech input unit, a new method of user-friendly speech input in speech recognition system. We focused the user friendliness on hands-free and microphone independence in speech recognition applications. Our module adopts two algorithms, the automatic speech detection and speech enhancement based on the microphone array-based beamforming method. In the performance evaluation of speech detection, within-200msec accuracy with respect to the manually detected positions is about 97percent under the noise environments of 25dB of the SNR. The microphone array-based speech enhancement using the delay-and-sum beamforming algorithm shows about 6dB of maximum SNR gain over a single microphone and more than 12% of error reduction rate in speech recognition.