• Proceedings of the Korea Water Resources Association Conference
• /
• 2006.05a
• /
• pp.770-774
• /
• 2006

The determination of feasible design flood is the most important to control flood damage in river management. Model parameters should be calibrated using observed discharge but due to deficiency of observed data the parameters have been adopted by engineer's empirical sense. Storage coefficient in the Clark unit hydrograph method mainly affects magnitude of peak flood. This study is to estimate the storage coefficients based on the observed rainfall-runoff events at the four stage stations in the Hantan river basin. Model calibration is the process of adjusting model parameter values until model results match historical data. An objective function which is the percent difference between the observed and computed peak flows is available for measuring the goodness-of-fit between computed and observed hydrographs. By sensitivity analysis for the storage coefficient, it has been shown that the storage coefficients affect the peak flows. The Clark parameters adopted in the River Rectification Basic Plan have been estimated through an iterative process designed to produce a hydrograph with the peak flow.

• Proceedings of the Korea Contents Association Conference
• /
• 2003.11a
• /
• pp.328-332
• /
• 2003

Since Jacquine introduced the image coding algorithm using fractal theory, many fractal image compression algorithms providing good quality at low bit rate have been proposed by Fisher and Beaumount et al.. But a problem of the previous implementations is that the decoding rests on an iterative procedure whose complexity is image -dependent. This paper proposes an iterative-free fractal image decoding algorithm to reduce the decoding time. In the proposed method, under the encoder previously with the same codebook image as an initial image to be used at the decoder, the fractal coefficients are obtained through calculating the similarity between the codebook image and a input image to be encoded. As the decoding process can be completed with received fractal coefficients and predefined initial image without repeated iterations, the decoding time could be remarkably reduced.

• Proceedings of the Korea Contents Association Conference
• /
• 2003.05a
• /
• pp.214-217
• /
• 2003

In this paper, we proposed an efficient blind watermarking algorithm using wavelet transform. The proposed algorithm inserts watermark into the high frequency subbands that were transformed by 1-level wavelet transform of original image. Watermark insertion is achieved by exchanging each the corresponding coefficients in the HL, LH, HH subbands according to be inserted watermark value. And watermark is extracted by the relation of wavelet coefficients without original image. Experimental results demonstrate that watermarked image has a good quality not to be able to be perceptible and is robust various attacks such as JEPG lossy compression, clipping and sharpening.

• Journal of Korean Tunnelling and Underground Space Association
• /
• v.18 no.5
• /
• pp.441-451
• /
• 2016

This study analyzed behavior of the segment lining considering connection type between inner-slab and segment lining for a double deck tunnel by Shield TBM. In order to establish the design requirements of inner-slab and segment lining in double deck tunnel, inner structure of double deck tunnel at each purpose was analyzed and compared connection type between inner-slab and segment lining. And analyses have been carried out through the beam-spring model by MIDAS Civil 2012. As a result of this study, inner-slab, connection type of between inner-slab and segment lining and Lateral earth pressure coefficients were analyzed to verify the significant design factors.

• Journal of the Korean Home Economics Association
• /
• v.35 no.5
• /
• pp.1.1-15
• /
• 1997

The purposes of this study were to identify the household's financial status by life cycle stage and no analyze contributing factors to financial planning for retirement preparation among Korean marred couples. For these purpose, 2074 married couples those being under 55 and having either single earner or dual earners were selected, and total sample was divided into three stages; young-aged(＜35), middle-aged(35-44) & old-aged(45-54). Statistics were frequencies, means, percentile, and logistic analysis. The results were as follows. First, old-aged had higher level of total income, total expenditure and total assets than either young-aged or middle-aged. In addition, households those holding private pensions were likely to have higher total income, total expenditure and total assets than those owning no private pension. while middle-aged had a highest total debts. Second, gini coefficients of total income and total expenditure between three aged groups were similar, but old-aged had the highest gini coefficient of total assets and total debts. In particular, gini coefficients of total assets and total debts of households those having no private pension were greater than those holding private pensions. third, contributing factors to private pension ownership of young-aged were family & household-related factor and financial factor, middle-aged's factors were household head's characteristics and financial factor. Also, old-aged's factors were household head's characteristics, family & household-related factor and financial factor.

• The Journal of the Korea Contents Association
• /
• v.10 no.5
• /
• pp.210-219
• /
• 2010

Consumers differ in both horizontally and vertically. Market segmentation aims to divide horizontally different (or heterogeneous) consumers into more similar (or homogeneous) small segments. A specific consumer, however, may differ in vertically. He (or she) may belong to a different market segment from another one where he (or she) belonged to before. In consumer panel data, the vertical difference can be observed by his (or her) choice among brand alternatives are changing over time. The consumer's vertical difference has been defined as 'dynamics'. In this research, we have developed a binary probit model with random-walk coefficients to capture the consumer's dynamics. With an application to a consumer panel data, we have examined how have the random-walk coefficients changed over time.

• Asian-Australasian Journal of Animal Sciences
• /
• v.15 no.2
• /
• pp.279-282
• /
• 2002

Twenty six male Hanwoo (Korean cattle) carcasses were measured for pH, temperature and instrumental color changes of loins during 24 h post-mortem carcass chilling at $4^{\circ}C$ in the cooler. The average internal temperature of loins was about $5^{\circ}C$ after 24 h of chilling, and with the exclusion of those with an ultimate pH>6.0 (dark-cutters), the average pH value was 5.5. When all carcasses were considered for the partial correlation coefficient between color and pH, with the temperature effect excluded, CIE $L^*$, $a^*$ and $b^*$ seemed to be affected significantly by pH during chilling process (p<0.001). However, when carcasses with dark-cutting condition were excluded, the correlation coefficients were much lower. In contrast, when the partial correlation coefficients between color and temperature, excluding the effect of pH on them, were analyzed, the relationship between color and temperature did not change much after values of DFD (dark, firm, dry) beef were excluded. The results suggested that the known interrelationship of color and pH in chilled beef loins be mainly due to the influence of temperature on pH and color.

• Journal of Korea Water Resources Association
• /
• v.53 no.10
• /
• pp.861-870
• /
• 2020

As the flow velocity and Reynolds number increase in rockfill porous media, the flow deviates from Darcy conditions. In this study, the permeability tests of rock column specimen and laboratory gabion weir model were carried out to investigate a head loss behaviour of flow through rockfill deposition in small river artificial recharge. Through column test, the nonlinear relationships between flow velocity and hydraulic gradient and coefficients were determined and the correlation formula of hydraulic mean radius and coefficients was proposed. The flow velocities and discharges in voids estimated by proposed equations were well matched with the measured values of laboratory gabion weir model.

• Journal of Korea Water Resources Association
• /
• v.37 no.11
• /
• pp.949-958
• /
• 2004

A combined experimental and numerical effort is presented for investigation of reflection of irregular waves due to rectangular submerged breakwaters. In the numerical model, the Reynolds equations are solved by a finite difference method and k-$\varepsilon$ model is employed for the turbulence analysis. To track the free surface displacement, the volume of fluid method is employed. Numerical predictions of transmission and reflection coefficients are verified by comparing to laboratory measurements. Very reasonable agreements are observed. The reflection coefficients become stronger in proportion to numbers of submerged breakwaters.

• Journal of Korea Water Resources Association
• /
• v.37 no.9
• /
• pp.729-736
• /
• 2004

Analysis of reflection of random waves propagating over rectangular submerged non-porous breakwaters was performed by using the eigenfunction expansion method. In this study, random waves were generated by superposition of several monochromatioc waves. Reflection coefficients were calculated by summing each numerical results of regular waves. Predicted results from the eigenfunction expansion method were in a good agreement with the results of laboratory measurements. Reflection coefficients of random waves were also resonated at the Bragg reflection condition.