• KSCE Journal of Civil and Environmental Engineering Research
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• v.29 no.3D
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• pp.357-362
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• 2009

The Investment to road projects has been a hot issue in the aspect of its possible overlapping or overinvestment in Korea. Therefore, additional road construction is not always accepted in these days. This paper investigated several indices including the country index and the road-extension rate index as well as a newly developed index for identifying and comparing road stocks among the OECD countries. Furthermore, the study has estimated some reasonable amount of additional road stocks of Korea when its GDP becomes twenty thousands per capita to forty thousands per capita in future by comparing the amount of stacks of OECD countries at those times. The result can be used for setting the target of road stocks in practical manner in the absence of the universally accepted theory in the road stock provision arena.

• Journal of the Korea Organic Resources Recycling Association
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• v.26 no.2
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• pp.85-93
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• 2018

Semi-dry anaerobic digestion experiment using dairy cattle manure collected from dairy cattle house was conducted to analyze efficiency of biogas production. As a first experiment, Biochemical Methane Potential (BMP) test was carried out according to certain ratio of sample mixtures: dairy cattle manure, pig slurry, and mixture of dairy cattle manure and pig slurry. The amount of methane accumulated during BMP test period was high in the experimental groups containing dairy cattle manure. As a second experiment, semi-dry anaerobic digestion experiment was carried out using only the dairy cattle manure collected from floor of the dairy cattle house. Judging from the experimental results, the optimum hydraulic retention time (HRT) of semi-dry anaerobic digestion for dairy cattle manure containing 13% of TS was 25 days. The amount biogas generated from the semi-dry anaerobic digestor with the TS of 13% of the dairy cattle manure ranged from 1.36~1.50v/v-d and the average was 1.44v/v-d. The optimum HRT of the semi-dry anaerobic digestor for dairy cattle manure containing TS of 15% and the semi-dry anaerobic digestor for dairy cattle manure containing TS of 17% was the same as 30 days. The amount biogas generated from the semi-dry anaerobic digestor with the TS of 15% of the dairy cattle manure ranged from 1.42~1.52v/v-d and the average was 1.47v/v-d. The amount biogas generated from the semi-dry anaerobic digestor with the TS of 17% of the dairy cattle manure ranged from 1.50~1.61v/v-d and the average was 1.55v/v-d.

• Journal of the Korea Organic Resources Recycling Association
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• v.8 no.2
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• pp.124-129
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• 2000

The purpose of this study is to estimate the degradation rate and process efficiency of the composting according to the salinity concentration. The samples of food waste for this study were collected in Pocheon-Gun, Kyungki-Do. The collected samples were adjusted to the optimum range of moisture content, pH and C/N ratio. After that, adding the saline, the samples with 3 different salinity concentrations(1%, 5% and 10%) were made. Then each sample was fed into the reactor with temperature controller. During the aerobic composting process, the change of the physical and chemical properties of the sample as temperature, pH, C/N ratio and $CO_2$ and $O_2$ concentration in the reactor were measured. From the experiment of this study, the result are following. The highest temperatures are $59^{\circ}C$ at RUN 1(1% salinity conc.), $49^{\circ}C$ at RUN 2(5% salinity conc.) and $45^{\circ}C$ at RUN 3(10% salinity conc.). The change of $CO_2$ production and $O_2$ consumption have the positive correlation with the change of the temperature. $CO_2$ production and $O_2$ consumption are peaked at the low salinity concentration. During composting, Run 1, RUN 2 and RUN 3 are increased pH to 8.9, 8.6 and 7.2 and slowly decreased C/N ratio to 18.9, 19.1 and 22.1 and moisture content to 51.1%, 53.7% and 55.0%, respectively. It is supposed that increasing salinity concentration causes the retarding of the microbial degradation activities during the composting. And for the efficient composting, the salinity concentration in the sample hat to be maintained below 5%.

• Korean Journal of Food Science and Technology
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• v.24 no.1
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• pp.65-69
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• 1992

The comparative effects of ethylene oxide(EO) fumigation and gamma irradiation (5 kGy) were determined on the chemical components of exportable ginseng-leaf tea which is required for improving the hygienic quality. Saponins and fatty acids detected in the samples were found to be resistant to both treatments at the practical levels. In an experiment on free sugar and amino acids, however, quantitative analysis has shown that glucose, lysine and histidine in the samples are significantly decreased by EO fumigation (p<0.05) and that negligible changes were observed in gamma-irradiated samples.

• Journal of Korean Society of Steel Construction
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• v.17 no.6 s.79
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• pp.717-726
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• 2005

This study investigates the bearing pressure distribution and design of an H-section steel column baseplate under concentric loading. In general, the size and thickness of the baseplate are determined with the assumption that the bearing pressure of the column baseplate is distributed uniformly. When the column is loaded lightly, however, the baseplate becomes smaller andthinner and the bearing pressure of the baseplate is distributed non-uniformly. In this study, the distribution of the bearing pressure is investigated using the experimental method and the analytical method. Seven specimens of the H-section steel column baseplate were fabricated and tested. The analysis of the specimens was performed using the finite element analysis program, ANSYS. It is not appropriate to use the Limit State Design,which assumes that the bearing pressure of the baseplate is distributed uniformly,because the bearing pressure is distributed non-uniformly and is concentrated under the column sectio.

• Journal of Navigation and Port Research
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• v.29 no.8 s.104
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• pp.735-740
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• 2005

In this paper, we designed a wedge type rail-clamp which can protect container crane from sudden wind blast with constant clamping force regardless of the operating period. When we design wedge type rail clamp, it is important to determine an angle of wedge which prevent rotating of jaw and for smooth operation when wind blows. Therefore, this paper suggest a process to decide an angle of wedge within proper range obtained by experimental analysis as well as FEA of the wedge type rail clamp. A model with $6^{\circ}$ wedge angle is the most proper model to use in rail clamp bemuse it generated satisfactory clamping force and rotating angle underdesign specification.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2012.10a
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• pp.769-772
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• 2012

Personal Information Article2 defines personal authentication information, secret information, bio information for personal information and it is stipulated under article29 that the one who have duties must take adequate technological, administrative, physical measures to prevent from illegal reading and sneaking. Also it is stipulated under information communication network law28(1), enforcement regulation9, Korea Communications Commitee notice. To satisfy this, the one who have to take security actions of personal information are required to take technological measures and establish positive measures to continuously manage it.The insurance of technological security is possible by encryption of personal information, secure management and operation of encryption key,taking personal information security level of providin access control of personal information reading and audit.In this paper, we will analyze various technologies of personal information encryption which are essencial component in technological security measuresof personal information. This paper will help choose which technological measures you should take in personal information security.

• Water for future
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• v.29 no.3
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• pp.163-176
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• 1996

When a pipe is deployed on a sloping bed, pumping power required for a discharge can be estimated immediately without any iteration process with an explicit form of a friction factor equation. Pumping power being given, however, traditional method requires an iteration process for the solution of discharge and pipe diameter even for the uniformly-rough pipe. You (1955b) has suggested explicit equations for the estimation of discharge and pipe diameter particularly for the cases of pipe on a slopintg bed without pumping and pipe on a horizontal bed with a pumping power. Based on his approach and previous results, the present researchers have developed explicit equations of discharge and pipe diameter for the general case of pipe on a sloping bed with a pumping power. The equations of boundary criteria are also presented in explicit way which render proper choice of various equations suitable for the flow condition between five characteristics. Verification studies are also carried out by applying the explicit equations to a practical example.

• Korean Journal of Environment and Ecology
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• v.6 no.2
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• pp.162-167
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• 1993

A mixed deciduous forest community in Mt. Sobaek was studied to determine the adequate number of plots of tree stratum for investigating forest community structure. Twenty l0m $\times$ l0m plots were set up iii the studied forest community, and species area curve. performance curve and statistical method were carried out. According to species-area curve, the minimal number of plots where a given percentage increase in number of plots produced less than the same percentage increase in number of species was eight. The minimal number of plots where a given percentage increase in number of plots produced less than the half of the percentage increase in number of plots was eleven. According to performance curve by importance value of the major species, the minimal number of plots where the dominant species was distinguished from the subdominant species was five. The minimal number of plots where the subdominant species was distinguished from each other was ten. Therefore, ten l0m $\times$ l0m plots seems to give an adequate sample for investigating structure of the studied forest community. Similarity index between the ten plots and total twenty plots was above 90%, and 95% confidence interval of species diversity of the ten plots was $\pm$ 0.073.

• Journal of Korean Society of Steel Construction
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• v.19 no.6
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• pp.695-702
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• 2007

The Thermal Prestressing Method for continuous composite girder bridges is a new design and construction method developed to induce initial composite stresses in the concrete slab at negative bending regions. Due to the induced initial stresses, prevention of tensile cracks at the concrete slab, reduction of steel girder section, and reduction of reinforcing bars are possible. Thus, the construction efficiency can be improved and the construction can be made more economical. The method for determining the optimum heating region of the thermal prestressing method has not been established although such method is essential for improving the efficiency of the design process. The trial-and-error method used in previous studies is far from efficient, and a more rational method for computing optimal heating region is required. In this study, an efficient method for determining the optimum heating region in using the thermal prestressing method was developed based on the neural network algorithm, which is widely adopted to pattern recognition, optimization, diagnosis, and estimation problems in various fields. Back-propagation algorithm, commonly used as a learning algorithm in neural network problems, was used for the training of the neural network. Through case studies of two-span and three-span continuous composite girder bridges using the developed procedure, the optimal heating regions were obtained.