• Journal of the Institute of Electronics Engineers of Korea SP
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• v.38 no.2
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• pp.138-148
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• 2001

Digital Video (DV) coding standards for digital video cassette recorder are based mainly on DCT and variable length coding. DV has low hardware complexity but high compressed bit rate of about 26 Mb/s. Thus, it is necessary to encode video with low complex video coding at the studios and then transcode compressed video into MPEG-2 for video-on-demand system. Because these coding methods exploit DCT, transcoding in the DCT domain can reduce computational complexity by excluding duplicated procedures. In transcoding DV into MPEC-2 intra coding, multiplying matrix by transformed data is used for 4:1:1-to-4:2:2 chroma format conversion and the conversion from 2-4-8 to 8-8 DCT mode, and therefore enables parallel processing. Variance of sub block for MPEG-2 rate control is computed completely in the DCT domain. These are verified through experiments. We estimate motion hierarchically using DCT coefficients for transcoding into MPEG-2 inter coding. First, we estimate motion of a macro block (MB) only with 4 DC values of 4 sub blocks and then estimate motion with 16-point MB using IDCT of 2$\times$2 low frequencies in each sub block, and finish estimation at a sub pixel as the fifth step. ME with overlapped search range shows better PSNR performance than ME without overlapping.

• Journal of the Korean Geotechnical Society
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• v.18 no.4
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• pp.339-347
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• 2002

An in-situ experiment was performed to evaluate the pullout resistance capacity of chains which is used as a reinforcement of reinforced earth wall. It was also considered that chain was combined with a bar or L-type steel angle by the transverse reinforcement member in the experiment. About 80 pullout tests were peformed with varying the lengths of chain(2.0m, 2.5m, and 3.0m), the combination of each transverse members(chain only, chain＋bar, or chain＋angle), and the vertical placement of reinforcements. In the case that uses a chain only and a chain combined with bar, the maximum displacement was about 150mm and load continuously increased to the ultimate tensile strength of chain, and then tension failure of chains occurred. But in the case of a chain combined with angle, the displacement decreased to about 100mm and so it was expected that this combination can constrain the displacement of chain. On the other hand, comparing the yielding pullout load measured in the field to that calculated by theoretical equation, it is shown that measured values are 1.2~3.0 times greater than those of calculated values according to the length of chain, normal vertical stress, and the combination of chain with transverse members. However, the difference in the increment of yielding pullout load between bar and angle is not clear but it appears almost the same increment. It is expected that chain can be safely used as reinforcements of reinforced earth wall, although a theoretical estimation of the pullout resistance capability of chain is too conservative.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.4 no.1
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• pp.103-112
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• 1984

This study is an effort to develop a series of empirical procedure for the determination of design flood for a small watershed based on the unit hydrograph theory. It is shown that a flood discharge of a watershed with a specific return period can be expressed as a product of its watershed area, rainfall factor, runoff factor and flood peak reduction factor. Since the procedures for the determination of rainfall factor and runoff factor were already developed in the previous study (13) a series of step-by-step procedure is devised to empirically determine the flood peak reduction factor in the present study. Using the methodology developed herein the 50-year design flood, which is of concern in the drainage of agricultural lands, is estimated for a watershed on upper Kyungan River and compared with the design floods by the existing methods now in use. The flood peak reduction factor was correlated with the dimensionless parameter consisted of the rainfall duration divided by the basin lag time, which was computed from the derived unit hydrographs by the method of moment. The unit hydrographs of various durations were synthesized by the method of build up and S-curve. A multiple correlation was also made between the basin lag time and the physiographic parameters of the watershed, i.e., the stream length and the average stream slope.

• Journal of Embryo Transfer
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• v.22 no.3
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• pp.143-147
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• 2007

Records on 546 Korea native pigs for average daily gain (ADG), age at 70 kg (D70 kg) and backfat thickness (BF) made between 2001 and 2006 in herds on National Institutes of Animal Science in Korea were used to estimate genetic parameters. The data was analyzed by the DF-REML (Derivative-Free Restricted Maximum Likelihood) program of Boldman using a single-trait animal model. Heritabilities were 0.26, 0.09, and 0.29 for ADG, D70 kg and BF, respectively. The phenotypic correlations of ADG with D70 kg and BF were -0.71 and 0.30. The phenotypic correlation of D70 kg with BF was -0.15. The genetic correlations of ADG with D70 kg and BF were -0.11, 0.41, respectively. The genetic correlation of D70 kg with BF was -0.16. The data of weights and measurements on body length, body height and chest width after age at 11 months (days to 330) were shown scarcely less differences compare to data of age at 11 months.

• 한국신재생에너지학회:학술대회논문집
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• 2005.06a
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• pp.638-642
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• 2005

For gas hydrate exploration, long offset multichannel seismic data acquired using by the 4km streamer length in Ulleung basin of the East Sea. The dataset was processed to define the BSRs (Bottom Simulating Reflectors) and to estimate the amount of gas hydrates. Confirmation of the presence of Bottom Simulating reflectors (BSR) and investigation of its physical properties from seismic section are important for gas hydrate detection. Specially, faster interval velocity overlying slower interval velocity indicates the likely presences of gas hydrate above BSR and free gas underneath BSR. In consequence, estimation of correct interval velocities and analysis of their spatial variations are critical processes for gas hydrate detection using seismic reflection data. Using Dix's equation, Root Mean Square (RMS) velocities can be converted into interval velocities. However, it is not a proper way to investigate interval velocities above and below BSR considering the fact that RMS velocities have poor resolution and correctness and the assumption that interval velocities increase along the depth. Therefore, we incorporated Migration Velocity Analysis (MVA) software produced by Landmark CO. to estimate correct interval velocities in detail. MVA is a process to yield velocities of sediments between layers using Common Mid Point (CMP) gathered seismic data. The CMP gathered data for MVA should be produced after basic processing steps to enhance the signal to noise ratio of the first reflections. Prestack depth migrated section is produced using interval velocities and interval velocities are key parameters governing qualities of prestack depth migration section. Correctness of interval velocities can be examined by the presence of Residual Move Out (RMO) on CMP gathered data. If there is no RMO, peaks of primary reflection events are flat in horizontal direction for all offsets of Common Reflection Point (CRP) gathers and it proves that prestack depth migration is done with correct velocity field. Used method in this study, Tomographic inversion needs two initial input data. One is the dataset obtained from the results of preprocessing by removing multiples and noise and stacked partially. The other is the depth domain velocity model build by smoothing and editing the interval velocity converted from RMS velocity. After the three times iteration of tomography inversion, Optimum interval velocity field can be fixed. The conclusion of this study as follow, the final Interval velocity around the BSR decreased to 1400 m/s from 2500 m/s abruptly. BSR is showed about 200m depth under the seabottom

• Research in Plant Disease
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• v.17 no.3
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• pp.317-325
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• 2011

Bacterial pustule of soybean (Glycine max) caused by Xanthomonas axonopodis pv. glycines is one of the most prevalent bacterial diseases of soybean in Korea, where it causes considerable yield loss. This study was carried out to develop yield prediction model for bacterial pustule by analyzing correlation between the percentage of diseased leaf area and yield. The severe disease incidence of soybean bacterial pustule caused yield losses by 19.8% in 2006 and 16.8% in 2007, respectively. Severity of bacterial pustule greatly affected on 100 seed weight and yield, but did not on stem length, number of branches per plant, number of pods per plant, number of seeds per plant. On the other hand, correlation coefficients between diseased leaf area and yield were $-0.93^*$('06) and $-0.77^*$('07), respectively. The regression equation obtained by analyzing correlation between the percentage of diseased leaf area and yield loss in 2006 and in 2007 was y = -3.2914x + 348.19($R^2$ = 0.8603) and y = -2.9671x + 302.08($R^2$ = 0.9411), respectively. These results will be helpful in estimating losses on a field-scale and thereby predicting the production of soybean.

• International Journal of Highway Engineering
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• v.13 no.2
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• pp.187-193
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• 2011

The stormwater runoff from road or expressway is known as one of important nonpoint pollution sources. To reduce the pollutants discharge from road or expressway, many best management practices(BMPs) have been applied and planned. Among the BMPs, road sweeping can be effective way to prevent pollutant washoff to environment. This study is performed to evaluate the characteristics of particles collected from the road by sweeping car. Size distribution and pollutant concentration of particles were analyzed. Based on the pollutant concentration and the specification of road such as length, width, and unit for pollutant generation, total amount of pollutant to be removed by road sweeping was estimated. Most of sediments collected by road sweeping was classified into sandy soil and fraction of fine grained soil was low. Although the concentrations of pollutants such as heavy metals in road sediments did not exceed the soil contamination criteria, washout of pollutants during sweeping work by spraying water might cause leaching of pollutants contained in sediments and thus resulted in low pollutant concentrations. Reduced amounts of pollutant by road sweeping showed 31.4% TSS reduction for ${\bigcirc}{\bigcirc}$ region and 7.7% TSS for ${\triangle}{\triangle}$ region. Other pollutants showed low reduction rate, because of their leaching by water spraying. Results from this study indicate that detailed and well-planned investigation for the road sweeping is necessary for the accurate estimation of pollutant reduction from road or expressway.

• Journal of Korean Society of Steel Construction
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• v.29 no.3
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• pp.229-236
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• 2017

The purpose of this study is to investigate the behavior and characteristics of rubber springs and calculate the compressive stiffness by performing dynamic compression tests of rubber springs. In order to carry out the dynamic compression test of rubber spring, total 9 rubber springs were tailored by calculating the shape factor of L80-D55, L90-D58, and L100-D60, and used for the experiments. Experiments were performed by controlling the compression according to the length of the rubber spring, and the compression was increased in the order of 5%, 10%, 15%, 20% and 25% of the strain. From the experimental results, the force-strain curves were obtained and it was confirmed that strength decrease and strength increase phenomenon occurred as the strain increased. In addition, it was confirmed that the decrease of stiffness and the increase of stiffness were clearly observed according to the size and diameter of the rubber spring, and the effective compression stiffness was estimated using the slope of the force-strain curve. By using the effective compressive stiffness, design values that can be used in actual design were presented.

• Journal of Korean Society of Transportation
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• v.24 no.3 s.89
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• pp.63-71
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• 2006

There were many theories to suggest the indicators that evaluate stability and reflect the plan in mixed traffic street in all traffic modes This Paper analyzed residential street of Suwon City adopting time-space occupancy index among these indicates. Three survey street. congregated into apartment house. were selected to analyze this and pictured by video camera over one hour. and the length of these street were 76m, 55m, and 34m each, and major street by each region, comparably high in Pedestrians and pass vehicles, were selected. Basic datum to calculate time-space occupancy index and time-space occupancy index per person was gathered through video analysis. i.e Parameters for pedestrians, cars, bicycles, average speed of bicycles, and parking car. There are some limitation to analyze LOS of mixed traffic street in all traffic modes, not pedestrian mall. Therefore this paper presented evaluation standard of LOS. In conclusion. the aim of this paper is to suggest modeling based on guidelines for evaluating LOS of mixed traffic street in all traffic modes. It is estimated that this will be influencing indicates for improving pedestrian environment, and Planning mixed traffic street in future.

• Progress in Medical Physics
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• v.21 no.3
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• pp.246-252
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• 2010

The purpose of this study provides measurements of radiation dose from MDCT of head, chest, abdomen and pelvic examinations. A series of dose quantities that are measured of patient weight to compare the dose received during MDCT examinations. Data collected included: weight together with CT dose descriptors, volume CT dose index (CTDIvol) and dose length product (DLP). The effective dose was also estimated and served as collective dose estimation data. Data from 1,774 adult patients attending for a CT examination of the head (n=520) or chest (n=531) or abdomen (n=724) was obtained from spiral CT units using a same CT protocol. Mean values of CTDIvol was a range of 48.6 mGy for head and 6.9, 10.5 mGy for chest, abdomen examinations, respectively. And mean values of DLP was range of 1,604 $mGy{\cdot}cm$ for head, 250 $mGy{\cdot}cm$ for chest, 575 $mGy{\cdot}cm$ for abdomen examinations, respectively. Mean effective dose values for head, chest, abdominal CT were 3.6, 4.2, and 8.6 mSv, respectively. The degree of CTDIvol and DLP was a positive correlation with weight. And there was a positive correlation for weight versus CTDIvol ($r^2$=0.62), DLP ($r^2$=0.694) in chest. And head was also positive correlation with weight versus CTDIvol ($r^2$=0.691), DLP ($r^2$=0.741). We conclude that CTDIvol and DLP is an important determinant of weight within the CT examinations. The results for this study suggest that CT protocol should be tailored according to patient weight.