• YAKHAK HOEJI
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• v.52 no.6
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• pp.480-487
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• 2008

We described an estimation of measurement uncertainty in quantitative analysis of 11-nor-9-carboxy-${\Delta}^9$-tetrahydrocannabinol (THCCOOH), the major metabolite of ${\Delta}^9$-tetrahydrocannabinol, in urine sample by solid-phase extraction (SPE) and GC/MS detection. The analytical results were compared and the different contributions to the uncertainty were evaluated. Inter-day and inter-person validation were performed using statistical analysis of several indicative factors. Measurement uncertainty associated with target analyte in real forensic samples was estimated using quality control (QC) data. Traceability of measurement was established through traceable standards, calibrated volumetric glassware and volume measuring device. The major factors of contribution to combined standard uncertainty, were calibration linearity, inter-day repeatability and inter-person reproducibility, while those associated with preparation of analytical standards and sampling volume were not so important considering the degree of contribution. Relative combined standard uncertainties associated with the described method was 12.05% for THCCOOH.

• Journal of Korean Society for Atmospheric Environment
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• v.32 no.3
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• pp.305-319
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• 2016

This study was carried out to evaluate the performance of two sampling methods, i.e., adsorbent tubes and canisters, for the measurement of ambient volatile organic compounds (VOCs). A total of 24 target VOCs were selected from a list of 48 priority hazardous air pollutants (HAPs) in Korea. The two sampling methods were investigated with a wide range of performance criteria such as repeatability, linearity, and lower detection limits. In addition, mean relative errors (MRE) and mean duplicate precisions (MDP) were estimated by inter-lab comparison studies for duplicate field samples. Precisions for the two methods appeared to be well comparable with the performance criteria recommended by USEPA TO-15 and TO-17 for canister and adsorbent methods, respectively. Correlations and variations between the VOCs concentrations determined by the two methods were generally good in most cases. However, MREs and MDPs for individual VOCs appeared to be widely ranged, depending on each VOC. This implies that the two methods have its own advantages and disadvantages in determining a variety of VOCs in ambient air, and neither of which has absolute superiority. Finally, 9 of 24 VOCs were found to be difficult to determine by either methods due to their unstability in a canister, and lack of appropriate standard materials. Thus, it is suggested that development of measurement methods for such unstable VOCs is an urgent task from a viewpoint of HAPs management.

• Journal of Conservation Science
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• v.23
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• pp.73-80
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• 2008

This article aims to turn out the authentication of archaeological materials by using the paleodose measurement to fine sand-size quartz grains obtained by micro sampling technique. We firstly revealed the validity of micro sampling technique from the paleodoses of two bricks related to Muryong Royal Tomb of Baekje Kingdom. For the purpose of authentication test, four archaeological materials were selected, because they have been insisted that they were manufactured in Goguryeo Kingdom era. After obtaining very few quartz grains by micro sampling technique, each paleodose was evaluated by using SGR (single grain regenerative dose method). All values were very low below 0.2Gy and the reliability was found from those values by using SAR (single aliquot regenerative dose method). Considering the archaeological situation and the general paleodose, the burial time for 1,000 years generally corresponds to about 3.5Gy in Korea, it is concluded that these archaeological materials are all modern counterfeits.

• Journal of Broadcast Engineering
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• v.19 no.2
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• pp.227-239
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• 2014

This paper proposes an enhance prediction for conventional near-lossless coder to effectively lower external memory bandwidth in image processing SoC. First, we utilize an already reconstructed green component as a base of predictor of the other color component because high correlation between RGB color components usually exists. Next, we can improve prediction performance by applying variable block size prediction. Lastly, we use minimum internal memory and improve a temporal prediction performance by using a template dictionary that is sampled in previous frame. Experimental results show that the proposed algorithm shows better performance than the previous works. Natural images have approximately 30% improvement in coding efficiency and CG images have 60% improvement on average.

• 제어로봇시스템학회:학술대회논문집
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• 2003.10a
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• pp.156-161
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• 2003

It is an interest problem to predict substance distributions in three-dimensional space. Recently, a research field as Geostatistics is advanced. It is a kind of inter- or extrapolation mathematically. Some useful means for the inter- and extrapolation are known, in which slide window method with neural networks is hopeful one. We propose multi-dimensional extrapolation using multi-layer neural networks and the slide-window method. The multi-dimensional extrapolation is not similar to one-dimension. It has plural algorithms. We researched line predictors and local-plain predictors I two-dimensional space. The both predictors are equivalent; however, in multi-dimensional extrapolation, it is very important to find the direction of predictions. Especially, since the slide window method requires information to predict the future in sampling data, if they are not ordered appropriately in the direction, the predictor cannot operate. We tested the extrapolation for typical two-dimensional functions, and found an excellent character of slide-window method based on local-plain. By using the method, we can extrapolate the function until twice-outer regions of the definitions.

• Journal of Communications and Networks
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• v.18 no.1
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• pp.27-39
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• 2016

This paper derives and analyzes a novel block fast Fourier transform (FFT) based joint detection algorithm. The paper compares the performance and complexity of the novel block-FFT based joint detector to that of the Cholesky based joint detector and single user detection algorithms. The novel algorithm can operate at chip rate sampling, as well as higher sampling rates. For the performance/complexity analysis, the time division duplex (TDD) mode of a wideband code division multiplex access (WCDMA) is considered. The results indicate that the performance of the fast FFT based joint detector is comparable to that of the Cholesky based joint detector, and much superior to that of single user detection algorithms. On the other hand, the complexity of the fast FFT based joint detector is significantly lower than that of the Cholesky based joint detector and less than that of the single user detection algorithms. For the Cholesky based joint detector, the approximate Cholesky decomposition is applied. Moreover, the novel method can also be applied to any generic multiple-input-multiple-output (MIMO) system.

• Journal of Digital Contents Society
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• v.18 no.1
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• pp.141-147
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• 2017

Scalable extension of High Efficiency Video Coding (SHVC) standard uses the up-sampled residual data from the base layer to make a residual data in the enhancement layer. This paper describes an efficient algorithm for improving coding gain by using the filtered residual signal of base layer in the Scalable extension of High Efficiency Video Coding (SHVC). The proposed adaptive filter selection mechanism uses the smoothing and sharpening filters to enhance the quality of inter-layer prediction. Based on two filters and the existing up-sampling filter, a rate-distortion (RD)-cost fuction-based competitive scheme is proposed to get better quality of video. Experimental results showed that average BD-rate gains of 1.5%, 2.1%, and 1.7% for Y, U and V components, respectively, were achieved, compared with SHVC reference software 5.0, which is based on HEVC reference model (HM) 13.

• Journal of Environmental Science International
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• v.27 no.12
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• pp.1271-1277
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• 2018

The National Environmental Specimen Bank (NESB) has been sampling and cryogenically preserving various wildlife specimens to monitor bio-accumulations of chemical pollutants since 2010. Recently, the NESB set up a plan to develop reference materials at their facility to assure the analytical quality of and validate the analytical methods for their monitoring samples. One of the crucial characteristics of reference materials is intra- and inter-bottle homogeneity. In this study, we used ANOVA for total mercury concentrations in some samples to validate their homogeneities after milling and homogenization. We examined the intra- and inter-bottle homogeneities of two cryogenically-milled samples (Korean mussel (Mytilus coruscus) and black-tailed gull's egg (Larus crassirostris). The variations in the total mercury concentrations were not significantly different intra- and inter-bottle (mussel: F=0.74, p=0.67; gull egg: F=1.96, p=0.10). Additionally, the relative standard deviations of the total mercury concentrations showed low values (mussel: 2.02%, gull egg: 1.78%). Therefore, the cryogenic-milling process statistically proves the homogeneity of the materials of mussels and sea gull eggs for chemical analysis for total mercury.

• Journal of Institute of Control, Robotics and Systems
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• v.15 no.6
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• pp.626-633
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• 2009

A motion planning algorithm is presented in this paper for a commercialized quadruped walking of robot pet. Stable walking is the basic requirement for a commercial-purpose legged robot. In order to secure the walking stability, modified body sway to the centroid of support polygon is addressed. By representation of walking motion with respect to the world coordinate system rather than body coordinate, it is possible to design the several gaits in unified fashion. The initial gait posture is introduced to maximize the stride and to achieve fast walking. The proposed walking motion planning is verified through computer simulation and experiments.

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 2008.11a
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• pp.99-102
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• 2008

OFDM 시스템에서는 수신단의 샘플링 주파수가 정확하지 않을 경우 샘플링 주파수 옵셋으로 인한 ICI(Inter-Carrier Interference) 현상이 발생하여 수신 성능의 열화를 초래한다. 일반적으로 샘플링 주파수 옵셋의 추정은 연속된 2개의 OFDM 심볼의 파일럿 신호 또는 약속된 신호간의 상관을 통하여 수행된다. 본 논문에서는 주파수 영역에서 연속된 심볼들 간의 다양한 조합을 이용하여 샘플링 주파수 옵셋을 추정하고 그 성능을 비교한다. 이를 위해 각 방식을 DVB-T 시스템에 적용하여 모의실험을 수행한 결과와 기존 기법과의 성능을 비교 분석하였으며, 그 결과 AWGN 채널 환경에서 샘플링 주파수 옵셋 추정 성능을 향상시킬 수 있음을 확인하였다.