• Geophysics and Geophysical Exploration
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• v.19 no.2
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• pp.76-83
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• 2016

Migration image can be distorted due to reflected waves in the source and receiver wavefields when discontinuities of input velocity model exist in seismic imaging. To remove reflected waves coming from layer interfaces, it is a common practice to smooth the velocity model for migration. If the velocity model is smoothed, however, the subsurface image can be distorted because the velocity changes around interfaces. In this paper, we attempt to minimize the distortion by reducing reflection energy in the source and receiver wavefields through acoustic impedance homogenization. To make acoustic impedance constant, we define fake density model and use it for migration. When the acoustic impedance is constant over all layers, the reflection coefficient at normal incidence becomes zero and the minimized reflection energy results in the improvement of migration result. To verify our algorithm, we implement the reverse-time migration using cell-based finite-difference method. Through numerical examples, we can note that the migration image is improved at the layer interfaces with high velocity contrast, and it shows the marked improvement particularly in the shallow part.

• Geophysics and Geophysical Exploration
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• v.13 no.4
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• pp.323-329
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• 2010

Three deconvolution methods were applied to stacked seismic data obtained to investigate gas-hydrates in the Ulleung Basin, East Sea: (1) minimum-phase spiking deconvolution, (2) minimum-phase spiking deconvolution using an averaged wavelet from all traces, and (3) deterministic deconvolution using a wavelet with phases computed from well-logs. We analyzed the resolving property of these methods for lithological boundaries. The first deconvolution method increases temporal resolution but decreases lateral continuity. The second method shows, in an overall sense, similar results to the spiking deconvolution using a minimum phase wavelet for each trace; however, it results in a more consistent and continuous bottom-simulating reflector (BSR) and better resolved sub-BSR reflectors. The results from the third method reveal more detailed internal structures of debris-flow deposits and increased continuity of reflectors; in addition, the seafloor reflection and the BSR appear to have changed to a zero-phase waveform. These properties help more precisely estimate the distribution and reserves of gas hydrates in the exploration area by improving analysis of facies and amplitude of the BSR.

• Journal of Ginseng Research
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• v.33 no.2
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• pp.127-131
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• 2009

The plant protection rate of the marketed microbial products for ginseng cultivation was investigated against Rhizoctoina solani and Pythium sp. in a seedling pot experiment. A significant difference was found among the mean plant protection rates (Pm) of the microbial products, including Tolclofos-methyl (Rhizolex). The best microbial product, C-ISR2, showed a 33% and 33.6% net Pm (total Pm-control Pm) in the two tests against Rhizoctonia solani. In one test with a 58.6% control plot Pm, the total pm was 91.6%, indicating that plant protection can be done only with a microbial product in a well-conditioned field. The net Pm of C-ISR2 against Pythium sp. was 26.4%. The net Pm of a microbial product against a pathogen seems to be fixed. A significant negative linear correlation was found between the Pm and the coefficient of variation (CV) of the protection rate in all the three experiments. This indicates that the protection processes of control, microbial products, and chemical pesticides are in the same system. Pm was only dependent on CV, probably due to each seedling's microenvironment. In the linear correlation equation between the Pm and the CV of the microbial products and the control plot, the intercept of the vertical axis will be the theoretical Pm when CV is zero.

• Journal of Convergence Society for SMB
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• v.3 no.2
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• pp.51-56
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• 2013

Real-time processing of sensor data network, is one of the important factors. Each node in the detected data are required to be transmitted within a certain time since the accurate processing is possible. Thus, the data nodes are successfully delivered within a specified time, it is very important to check whether the. Recently more and more accurate real-time embedded systems are reliable and haejyeoseo been able to provide sophisticated services. Because of the inherent complexity of embedded systems in the physical world and the difficulty of predicting the difficulty of a safe design constraints on the runtime violation of system as to cause unexpected causes. Each node data in time detected by the time required to be passed in the appropriate processing is possible because the data transfer time in this paper, the monitoring of the sensor network through a node are allowed to exist within the time range and transmits data to the server Analysis of the data transfer time for checking whether the system was implemented. Implementation of the data transmission time to the process for analyzing and presenting, according to the procedure suggested by the transit time required for analysis a time difference analysis method, a data collection method and a data transmission time and transmission time calculating method presented.

• Journal of the Korean Magnetics Society
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• v.24 no.3
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• pp.71-75
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• 2014

Ground state energy levels of the $Fe^{3+}$ paramagnetic impurity ion in stoichiometric $LiTaO_3$ and in congruent $LiTaO_3$ single crystals were calculated with electron paramagnetic resonance constants. Energy levels between six energy levels were obtained with spectroscopic splitting parameter g and zero field splitting constant D for $Fe^{3+}$ ion. The energy diagrams of $Fe^{3+}$ ion were different from different magnetic field directions ([100], [001], [111]) when magnetic field increases. The calculated ZFS energies of $Fe^{3+}$ ion in stoichiometric and congruent $LiTaO_3$ single crystals for ${\mid}{\pm}5/2$ > ${\leftrightarrow}{\mid}{\pm}3/2$ > and ${\mid}{\pm}3/2$ > ${\leftrightarrow}{\mid}{\pm}1/2$ > transitions were 12.300 GHz and 6.150 GHz, and 59.358 GHz and 29.679 GHz, respectively. It turns out that energy levels of $Fe^{3+}$ paramagnetic impurity in $LiTaO_3$ crystal are different from different crystal growing condition.

• Elastomers and Composites
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• v.37 no.2
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• pp.79-85
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• 2002

Ethyl-branched polyethylene [PE(2)] containing 2mole% ethyl branch and three ethylene-propylene rubbers (EPR's) having the same ethylene(E)-propylene(P) molar ratio(E/P=50/50) with different stereoregularity, that is, random EPR (r-EPR), alternating-EPR (alt-EPR) and isotactic-alternating-EPR (iso-alt-EPR) were mixed for the investigation or their properties depending on the stereoregularity. Crystallinity of the prepared blends decreased with increasing content of amorphous EPR because of a decrease in both the degree of annealing and kinetics of diffusion of the crystallizable polymer content. With blend composition, crystallinity was reduced with the stereoregularity in EPR. The thermodynamic interaction parameter(x) for the three blend systems approximately equals to zero near the melting point. These systems were determined to be miscible on a molecular scale near or above the crystalline melting point or the crystalline PE(2). From the measurement of $T_m$ vs. $T_c$, the behavior of PE(2) is mainly due to a diluent effect of EPR component. The spherulite size measured by small angle light scattering (SALS) technique depended upon blend composition, and stereoregularity of EPR. The size of spherulite was enlarged with the content of rubbery EPR and the decrease of stereoregularity in EPR.

• International Commerce and Information Review
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• v.14 no.4
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• pp.459-490
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• 2012

The performance of FTA has a close relationship with the application of FTA by exporting companies. However, most existing literatures focus on the study of policies and economic results of FTA. Moreover, these researches based on a presupposition that exporting companies could make good use of FTA. Actually, these assumptions are clearly contrary to the reality of FTA application of exporting companies in Korea and the results are significantly differ from the performance of FTA. Based on the investigation of utilization of FTA, applied by export companies in Korea, this study tries to find out the most efficient strategies of the application of FTA. And the objective of this study is to propose some practical suggestions for export companies based on the case an alysis which will help them to improve performances of Korea-ASEAN FTA application. As the prior investigation of CEO's characters, application of FTA, and the implement of FTA, we got the fact that among lots of marketing strategies, Korea-ASEAN FTA is used extensively by large export companies. However, most of small and medium-sized export enterprises would like to choose conventional tariff, such as Lower tariffs and zero tariff as the main marketing strategies. In other words, because of lacking of human resources and infrastructure, the application of Korea-ASEAN FTA strategy is hard to achieve.

• Journal of dental hygiene science
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• v.18 no.4
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• pp.265-270
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• 2018

The purpose of this study was to investigate the chemical properties of some commercially available mouthwashes and to ascertain whether the mouthwashes accelerated mineral loss in dental enamel. Five commercially available mouthwashes were selected from the three largest malls in Korea: Perio Total 7 Aqua Cool Mint Strong $Fresh^{TM}$ (PS; LG Household & Health Care Ltd.), Garglin $Original^{TM}$ (Dong-A Pharmaceutical Co., Ltd.), Garglin $Zero^{TM}$ (Dong-A Pharmaceutical Co., Ltd.), Listerine Naturals $Citrus^{TM}$ (LC; IDS Manufacturing Ltd.), and Listerine Cool $Mint^{TM}$ (LM; IDS Manufacturing Ltd.). The composition, pH, and titratable acidity of the mouthwashes were investigated. Six bovine teeth specimens were prepared for each mouthwash group. Each of the six specimens was individually immersed in 30 ml aliquots of mouthwash for 1 minute, 30 minutes, 90 minutes, and 120 minutes, and the samples were placed in a $36.5^{\circ}C$ stirred incubator. The degree of mineral loss (${\Delta}F$) of the tooth surface area exposed to mouthwash, compared with normal teeth, was analyzed by quantitative light-induced fluorescence-digital. The difference in ${\Delta}F$ among mouthwash groups was examined by the Kruskal-Wallis H test (${\alpha}=0.05$). The contents of mouthwashes differed between Listerine and other products, and the pH ranged from 4.09 to 6.75. The titratable acidity of PS was the lowest at 0.63 ml and highest at 9.25 ml for LM. Minor mineral loss was observed when dental specimens were immersed in the Listerine products (LC and LM) for more than 90 minutes, but the degree of mineral loss for Listerine products was not statistically significantly different from that for groups without mineral loss. In conclusion, all five commercially available mouthwashes showed no harmful effects on tooth enamel.

• Journal of Digital Convergence
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• v.17 no.12
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• pp.393-398
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• 2019

This study aimed to suggest the optimum number of rinsing by researching changes in optical density and pH in accordance with the number of rinsing after toothbrushing, and then verifying the amount of residual toothpaste in mouth. Total 14 university students who had healthy body with no difficulties in daily life were selected from the students of K university in Daegu as the research subjects. The research subjects rinsed their mouths with 40ml of water from zero time to 12 times after toothbrushing. After collecting each rinsing water, the optical density and pH were measured. In the results of measuring the optical density value of each rinsing water, the rinsing water of six-seven times or more after toothbrushing showed the constant value of optical density, which was statistically significant(p<0.05). There were no differences in accordance with the amount of toothpaste such as 1g, 1.5g, and 2g. Based on such results of this study, it would be necessary to provide the education of the use of dentifrice, and also to have diverse researches on the effects of residual dentifrice in mouth on the oral cavity.

• Journal of the Institute of Electronics Engineers of Korea TE
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• v.37 no.1
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• pp.35-41
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• 2000

This paper considers the consturction of 24/25 I-NRZI (Interleaved - Non Return to Zero Inverse) modulator designs for DVCR (Digital Video Cassette Recorder), and size of validity bit in order to store the amplitude value of square-wave and the standard data ( sine and cosine coefficients) at ROM Table that to acceptable the spectrum standard. The validity bit size of the standard data and the amplitude value of square-wave that to store at ROM Table are affected the size of pilot signal on the output spectrum, and the hardware size of modulator. At the designable 24/25 I-NRZI modulator, we simulated using random pattern (F0,F1,F2) that to verification the output data of the spectrum. Moreover, the resultant of the spectrum analysis, at the optimizing value, is 0.065 on the amplitude value of square-wave, and 3bit on the size of bit in order to store the standared data at ROM Table. In order to verify the hardware of designable 24/25 I-NRZI modulator, we perform to modeling of C-language firstly, and coding to Verilog HDL (Cadence Verilog XL) and synthesized using Synopsys (Library "Samsung KG75") tool as a base of spectrum results. In a foundation of this result, we are considered the size of hardware. In this paper, a considerable 24/25 I-NRZI modulator designable less than 10,000 gates as that is improved consturction as regards the path method of pre-coder etc, and able to application digital camcorders as now practical use.