• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
• /
• 1996.11a
• /
• pp.122-127
• /
• 1996

본 실험은 미국 Washington 주 V 도시에서 1987년과 1908년에 PCP 유출사고로 발생된 PCP 오염토양을 처리하는 연구로 heme과 과산화수소를 이용한 abiotic 기술로 14C-PCP를 이용하여 PCP의 거동조사로 물질수지 연구와 pan 연구를 통하여 오염토양에서 PCP 제거되는 분해능을 조사하였다. $^{14}$ C-PCP를 이용한 오염토양에서 물질수지는 2g 오염토양당 0.035 g heme과 0.11g 과산화수소를 첨가하여 반응 24시간 동안 반응시킨후 완전 산화율은 20%, 토양잔류 27%, 그리고 용매상에는 38%로 총 $^{14}$ C-PCP가 회수율은 85% 이었다. PCP 유출사고로 보관된 오염토양 처리를 위한 pan 연구결과 24시간내 초기 PCP 987 mg/kg soil에서 85%가 제거되고, 서서히 분해되어 33일 에는 95% 분해능을 보여주고 있다.

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.26 no.6B
• /
• pp.802-809
• /
• 2001

이동통신 채널에서 압축된 동영상 정보를 전송하게 되면 다경로 전송으로 인한 페이딩 영향과 시, 공간상으로 압축된 동영상 정보의 오류 전파 때문에 최종적으로 복원되는 동영상 신호의 화질이 크게 저하된다. 이에 능동적으로 대처하기 위하여 다양한 오류 정정 부호화 기법들이 전체 정보량 증가를 감수하면서 제안되어 왔다. 본 논문에서는 이동통신 환경에서 압축된 동영상 신호의 안정적인 전송을 위해서 ITU-T H.263 기법으로 압축된 동영상 정보에 두 종류의 다전송율 지원 오류 정정 부호들을 적용한 경우의 동영상 보호 능력을 분석 비교한다. 즉 표준기법에서 널리 사용되는 RCPC(rate compatible punctured convolutional) 부호와 RC 특성을 갖는 turbo 부호인 RCPT(rate compatible punctured turbo) 부호를 사용한 동영상 부호 시스템의 성능을 가산 백색 잡음 채널과 레일리 페이딩 채널에서 해석하고, 압축과 오류 정정 부호화율의 동시 최적화를 살펴본다.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
• /
• 2013.10a
• /
• pp.1024-1026
• /
• 2013

DVC (Distributed Video Coding) techniques provides a basic theory for the implementation of low-power video encoder. Conventional methods decide the parity bit request at decoder side. These are effective in controlling the bit-rate, but, are not able to control the visual quality. Thus, this paper presents an effective method of estimating visual quality improved by correcting the virtual channel noise for the reconstructed frame. Through several experiments, it is shown that the proposed method are able to estimate effectively the decoded visual quality.

• Journal of Digital Convergence
• /
• v.10 no.8
• /
• pp.173-178
• /
• 2012

In the generated model for the recognition vocabulary, tri-phones which is not make preparations are produced. Therefore this model does not generate an initial estimate of parameter words, and the system can not configure the model appear as disadvantages. As a result, the sophistication of the Gaussian model is fall will degrade recognition. In this system, we propose the error correction system using out-of vocabulary rejection algorithm. When the systems are creating a vocabulary recognition model, recognition rates are improved to refuse the vocabulary which is not registered. In addition, this system is seized the lexical analysis and meaning using probability distributions, and this system deactivates the string before phoneme change was applied. System analysis determine the rate of error correction using phoneme similarity rate and reliability, system performance comparison as a result of error correction rate improve represent 2.8% by method using error patterns, fault patterns, meaning patterns.

• Journal of Korea Soil Environment Society
• /
• v.4 no.3
• /
• pp.3-15
• /
• 1999

This paper includes the basic experimental results performed for developing an innovative and technologically feasible process wherein gaseous ozone, a powerful oxidant. is injected directly into vadose zone by which in-situ chemical degradation of semi- or, non-volatile petroleum product such as diesel fuel is derived. As ozone gas injected continuously(50mL/min, 119.0$\pm$6.1mg/L) into soil packed columns artificially contaminated with diesel fuel(initial concentration 1,485mg-DRO/kg/soil), the removal rates at the inlet and outlet point of 14hrs-operated column are 87.9% and 100.0%, respectively. On the other hand, soil vapor extraction system showed less than 30% of removal rates of residual diesel both at the inlet and outlet samples under the same experimental conditions which confirms the limited treatability of SVE in diesel contaminated soil.

• Journal of the Korean Society for Aeronautical & Space Sciences
• /
• v.32 no.4
• /
• pp.18-23
• /
• 2004

In this paper, material non-linear behavior of PZT wafer(3203HD, CTS) under high electric field and stress is experimentally investigated and the non-linearity of the PZT wafer is numerically simulated. Empirical functions that can represent the non-linear behavior of the PZT wafer have been extracted based on the measured piezo-strain under stress. The functions are implemented in an incremental finite element formulation for material non-linear analysis. New definition of the piezoelectric constant and the incremental strain are incorporated into the finite element formulation for a better reproduction of the non-linear behavior. With the new definition of the in incremental piero-strain the measured non-linear behavior of the PZT wafer has been accurately reproduced even for high electric field. For validation of the measured non-linear characteristics and the proposed approach, a PZT bimorph beam actuator has been numerically and experimentally tested. The predicted actuation displacement, based on the material nonlinear finite element analysis, showed a good agreement with the measured one.

• The Transactions of the Korea Information Processing Society
• /
• v.3 no.5
• /
• pp.1307-1316
• /
• 1996

In this paper, we propose a vector quantization method which uses a dynamic address mapping based on exploring the high interblock correlation. In the proposed method, we reduce bit-rate by defining an address transform function, which maps a VQ address of an input block which will be encoded into a new address in the reordered codebook by using side match error. In one case that an original address can be transformed into a new transformed address which is lower than the threshold value, we encode the new address of the transformed convector, and in the other case we encode the address of the original convector which is not transformed. Experimental results indicate that the proposed scheme reduces the bit-rate by 45~50% compared with the ordi-nary VQ method forimage compression, at the same quality of the reconstructed image as that of the ordinary VQ system.

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.32 no.10C
• /
• pp.950-958
• /
• 2007

This paper presents an efficient packet loss resilient scheme for real-time video transmission over the Internet. By analyzing the temporal and spatial dependencies in inter- and intra-frames, we assign forward error correction codes (FEC) across video packets for minimizing the effect of error concealment and error propagation from packet loss. To achieve optimal allocation of FEC codes, we formulate the effect of packet loss on video quality degradation as packet distortion model. Then we propose an unequal FEC assignment scheme with low complexity based on packet correction rate, which uses the packet distortion model and includes channel status information. Simulation results show that the proposed FEC assignment scheme gives substantial improvement for the received video quality in packet lossy networks. Furthermore the proposed scheme achieves relatively smaller degradation of video quality with higher packet loss rates.

• Polymer(Korea)
• /
• v.31 no.5
• /
• pp.410-416
• /
• 2007

Monodisperse polymer particles were prepared via one- step seeded polymerization using PMMA as seed particles, and HDDA, triEGDMA or EGDMA as crosslinking monomer. For the study, the effects of 1) the ratio of the absorbed monomer to the seed polymer particles (swelling ratio), 2) the characteristics of crosslinking monomer, 3) electroless Ni plating, and 4) electroless Au Plating on the variation of mechanical properties of polymer particles, such as recovery rate, K-values, breaking strength and breaking displacement were investigated by using MCT (micro compression test). It was observed that swelling ratio of polymer particles influenced only on breaking strength of polymer Particles, while electroless plating did on recovery rate, K-values ($K_{10}\;and\;K_{20}$) and breaking strength of electroless plated polymer particles. However, breaking displacement and K-values ($K_{30}{\sim}K_{50}$) were more or less insensitive to electroless plating.

• Journal of Biomedical Engineering Research
• /
• v.21 no.3 s.61
• /
• pp.247-254
• /
• 2000

We propose an efficient MR image compression technique using fractal coding in wavelet transform domain. In the Proposed method , we construct significant coefficient trees with the absolute values of discrete wavelet transform coefficients and then perform the fractal coding with the information of significant coefficients having high energy. For MR images, most Pixels including background have very low gray level values, the number of significant coefficients is small. so we can expect high compression rate. In addition. since this method uses the fractal coding in wavelet transform domain, blocking artifact is reduced prominently and edges sensitive to human visual system are well preserved. As a result of computer simulation, we obtained the reconstructed images with better quality than those by JPEG at the low bit rates below 0.33[bpp].