• KSCE Journal of Civil and Environmental Engineering Research
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• v.36 no.4
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• pp.617-625
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• 2016

The objective of this study was to evaluate the groundwater drawdown and streamflow depletion due to each groundwater pumping from 110 wells located near stream using the Hunt's analytical solution (1999). The calculated results revealed that the streamflow depletion rate divided by the pumping rate for each well location mostly exceeded about 80% of pumping rate on average for 5 years. The results also showed that the stream boundary condition has made the influence distance shorter and the drawdown distribution skewed except for the streambed hydraulic conductivity and the stream bed factor (SBF) lower than $1.0{\times}10^{-9}m/s$ and 1.0, respectively. It was found that the groundwater pumping has significant impacts on the stream depletion showing above 80 % of stream depletion rate when the streambed hydraulic conductivity is higher than $1.0{\times}10^{-7}m/s$ and the stream depletion factor(SDF) is lower than 100. However, for other conditions, the SDF is not sufficient to be used as a criterion for determining whether the pumping has great impacts on stream depletion or not. Furthermore, the variation of the streambed hydraulic conductance has little change in stream depletion rate for the condition that the stream width is greater than 400 m.

• Korean journal of food and cookery science
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• v.17 no.5
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• pp.503-509
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• 2001

The effects of salting methods on textural properties of Kakdugi were evaluated during fermentation at 1$0^{\circ}C$ for up to 52 days. Kakdugi samples were prepared by 4 different salting methods at final salt concentration of 1.5%, which is appropriate for organoleptic quality. The salting methods for radish cubes(2 cm size) of Kakdugi were as follows; 1) Treatment S-1: spraying dry salt uniformly on to the radish cubes at 1.5%(w/w) and holding for 1 hr, 2) Treatment S-5: spraying dry salt uniformly on to the radish cubes at 1.2%(w/w) and holding for 5 hr, 3) Treatment B-1: brining radish cubes in a 8.5%(w/v) salt solution for 1 hr, 4) Treatment B-5: brining radish cubes in a 4.0%(w/v) salt solution for 5 hr. The contents of water soluble pectin, total soluble solid and PG activity were increased as the fermentation periods increased. A majority of total dietary fiber(TDF) consisted of soluble dietary fiber(SDF), and the amount of insoluble dietary fiber(IDF) was relatively small in Kakdugi during fermentation. Furthermore, an increase in SDF and a consequent decrease in IDF contents were observed with the fermentation time increased.

• Journal of the Korean Institute of Telematics and Electronics B
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• v.32B no.1
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• pp.110-119
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• 1995

The lateral resolution in an ultrasound imaging system is one of the most important factors for quality of the image and is determined by the beam focusing. For the better lateral resolution SDF(Sampled Delay Focusing) capable of digital focusing was proposed. The second-order sampling, one of band-width sampling methods, is suggested as being the best suitable for SDF because it allows total digital processing and is simple and economical. By proving that it introduces too much error, this article shows the second-order sampling is not appropriate for sampling of the wide-band signal generally used in ultrasound imaging systems. Also, this article suggests new sampling methods that maintain the advantages and reduce the unavoidable errors of the second-order sampling method. From computer simulation it is expected that the proposed methods reduce the errors of the second-order sampling method and can be used in real applications.

• Journal of the Korea Concrete Institute
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• v.12 no.5
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• pp.141-151
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• 2000

Compressive strength, sulfate deterioration factor(SDF) and length change of 5 types of mortars immersed in sodium sulfate solution were observed. As the results of tests, it was found that the sulfate resistance of blended cement mortars were superior to that of portland cement mortars. Pore volume with diameter larger than 0.1 $\mu\textrm{m}$ of 5 types of pastes indicated that the micro-structures of blended cement pastes were denser, due to pozzolan reaction and latent hydraulic properties, than those of portland cement pastes. The XRD, ESEM, EDS and TG analyses demonstrated that the reactants such as ettringite and gypsum were significantly formed in portland cement pastes. Besides, compared with the $Ca(OH)_2$ content of ordinary portland cement pastes immersed in water and sodium sulfate solution, the $Ca(OH)_2$ contents of fly ash blended cement and ground granulated blast-furnace slag cement paste were about 58% and 28% in water, and 55% and 20% in sodium sulfate solution, respectively.

• Journal of the Korean Society for Industrial and Applied Mathematics
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• v.26 no.4
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• pp.263-279
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• 2022

This paper presents an automatic inspection of defects in semiconductor images. We devise a statistical method to find defects on homogeneous background from the observation that it has a log-normal distribution. If computer aided design (CAD) data is available, we use it to construct a signed distance function (SDF) and change the pixel values so that the average of pixel values along the level curve of the SDF is zero, so that the image has a homogeneous background. In the absence of CAD data, we devise a hybrid method consisting of a model-based algorithm and two neural networks. The model-based algorithm uses the first right singular vector to determine whether the image has a linear or complex structure. For an image with a linear structure, we remove the structure using the rank 1 approximation so that it has a homogeneous background. An image with a complex structure is inspected by two neural networks. We provide results of numerical experiments for the proposed methods.

• Journal of Nutrition and Health
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• v.28 no.1
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• pp.5-14
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• 1995

The present study was performed to investigate the effect of cereal fiber on lipid concentration of liver and serum in rats. Male Sprague-Dawley rats weighing 180$\pm$4g were divided into five groups by completely randomized block design : R, BR, B, W, and F. Each group fed a diet containing 0.7% cholesterol and a kind of cereal among rice(R), brown rice(BR), barley(B), whole wheat(W), and wheat flour(F) for 5 weeks. The results were summarized as follow : 1) Food intake. weight gain and feed efficiency ratio were not significantly different among the groups. 2) Fecal wet weight and dry weight were significantly higher in W group which fed the most amount of IDF(insoluble dietary fiber). 3) The weight of large intestine was significantly heavier in the W group compared to the others. But the weights of liver, stomach and small intestine were not significantly different among the groups. 4) Total lipid. triglyceride(TG) and total cholesterol(TC) content in liver were significantly different among the groups. The values were the lowest in the B group whose intake of SDF(soluble dietary fiber) was the highest 5) TC content in serum was not significantly different among the groups. TG content in serum was significantly lower in the rest groups than in the R group. HDL-c and free-c content in serum were significantly higher in the B group than in the rest groups. HDL-c/LDL-c, free-c/ester-c ratio were the highest in the B group but not significant. Above results show that the dietary fiber contained in cereals has physiological effects and they are different depending on fractions, IDF and SDF.

• Journal of the Earthquake Engineering Society of Korea
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• v.14 no.4
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• pp.23-28
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• 2010

This study evaluated the effect of vibration, level of lateral yielding strength, site conditions, ductility factor, strain-hardening ratio, and post-capping ratio of the strength limited bilinear SDF systems on the inelastic displacement ratio. The nonlinear response history analysis was conducted using 240 ground motions which were collected at the sites classified as site classes B, C, and D according to the NEHRP. To account for the P-$\Delta$ effects, this study considered negative stiffness ratios ranging from -0.1 to -0.5 of elastic stiffness. Four different damping ratios are used: 2, 5, 10, and 20%. From this study, an equation of inelastic displacement ratio was proposed using nonlinear regression analysis.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.35 no.1C
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• pp.1-7
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• 2010

In this paper, the performance of the soft-decision-and-forward (SDF) protocol in the cooperative communication network with one source, one relay, and one destination, where each node has two transmit and receive antennas, is analyzed in terms of the bit error rate (BER) obtained from the pairwise error probability (PEP). For the slow-varying Rayleigh fading channel, the optimal and suboptimal power allocation ratios are determined without feedback. The optimal power allocation can be obtained by minimizing the average PEP. For the tractability, an alternative strategy of maximizing the product SNR of direct and relay links, which we call the suboptimal power allocation, is considered. Through the numerical analysis, we show that the performance gap between the suboptimal and the optimal power allocation is negligible in the high SNR region.

• Journal of Soil and Groundwater Environment
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• v.21 no.1
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• pp.61-71
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• 2016

Visual MODFLOW was used for quantifying stream-aquifer interactions caused by seasonal groundwater pumping. A hypothetical conceptual model was assumed to represent a stream-aquifer system commonly found in Korea. The model considered a two-layered aquifer with the upper alluvium and the lower bedrock and a stream showing seasonal water level fluctuations. Our results show that seasonal variation of the stream depletion rate (SDR) as well as the groundwater depletion depends on the stream depletion factor (SDF), which is determined by aquifer parameters and the distance from the pumping well to the stream. For pumping wells with large SDF, groundwater was considerably depleted for a long time of years and the streamflow decreased throughout the whole year. The impacts of return flow were also examined by recalculating SDR with an assumed ratio of immediate irrigation return flow to the stream. Return flow over 50% of pumping rate could increase the streamflow during the period of seasonal pumping. The model also showed that SDR was affected by both the conductance between the aquifer and the stream bed and screen depths of the pumping well. Our results can be used for preliminary assessment of water budget analysis aimed to plan an integrated management of water resources in riparian areas threatened by heavy pumping.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.29 no.11A
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• pp.1263-1270
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• 2004

A low-power 64-point FFT/IFFT processor core is designed, which is an essential block in OFDM-based wireless LAM modems. The radix-2/418 DIF (Decimation-ln-Frequency) FFT algorithm is implemented using R2SDF (Radix-2 Single-path Delay Feedback) structure. Some design techniques for low-power implementation are considered from algorithm level to circuit level. Based on the analysis on infernal data flow, some unnecessary switching activities have been eliminated to minimize power dissipation. In circuit level, constant multipliers and complex-number multiplier in data-path are designed using truncation structure to reduce gate counts and power dissipation. The 64-point FFT/IFFT core designed in Verilog-HDL has about 28,100 gates, and timing simulation results using gate-level netlist with extracted SDF data show that it can safely operate up to 50-MHz＠2.5-V, resulting that a 64-point FFT/IFFT can be computed every 1.3-${\mu}\textrm{s}$. The functionality of the core was fully verified by FPGA implementation using various test vectors. The average SQNR of over 50-dB is achieved, and the average power consumption is about 69.3-mW with 50-MHz＠2.5-V.