• KSCE Journal of Civil and Environmental Engineering Research
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• v.14 no.4
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• pp.907-913
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• 1994

The design of railroad bridges differs from road bridges because of the interface between track structure and bridge structure. The track generally consists of Continuous Welded Rail(CWR) which is fixed by fasteners to the sleepers embedded in the ballast. The ballast provides the interface between the track structure and the bridge structure. Large longitudinal forces can develop from the temperature variation in rail and bridge structure. These longitudinal forces are specially important for long bridges because the bridge layout for span length, pier dimensions and arrangement and type of bearings can be governed by these forces. This report provides a comparison of longitudinal track forces determined by analysis and actual measured track forces. In recent practice the longitudinal track force for European railways is analyzed using a finite element analysis method. This method is very time-consuming and requires the detail design of the bridge to be complete. Redesign is required if the design criteria for longitudinal track forces are not satisfied. There is a need to develop a simple analysis method considering the large number of bridge structures and a relatively short design time on the Korean High Speed Rail Project. The analysis results presented herein, based on a simplified analysis, show good agreement with those obtained by finite element analysis, as well as with those measured on an actual track. The proposed analysis method is particularly useful for the preliminary design of bridge structures.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.37 no.6
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• pp.1063-1076
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• 2017

To improve the productivity of the earthwork, a fleet management system for construction equipment was suggested in previous studies. But there were some gaps between theory and practice. To overcome this problem, some opinions are gathered form experts and field engineers and four improvements have been proposed and reflected in the system. First, the previous system consists of one hardware module, so it is hard to install it at a control office and construction equipment at the same time. The server module for the office and the mobile module for construction equipment are separately developed. Second, the transportation algorithm that is used in the previous system can generate shortest paths for the earthwork distribution, but embankment areas are not gathered. This situation leads to a decrease in compaction productivity. A modified algorithm for earthwork distribution is suggested. Third, the automated coordinate transformation is performed to show the position of construction equipment on the 3D terrain in real-time. Fourth, construction equipment groups should be formed in the initial stage of earthwork and the number of equipment of each groups should be changed by operation status and site environment. But this functions did not work properly in the previous system. This problem is corrected in the proposed system. The improvements can make the proposed system much more realistic one and can leads to an increase in the productivity of earthwork operations.

• Journal of the Korea Organic Resources Recycling Association
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• v.25 no.3
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• pp.73-78
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• 2017

Objective of this experiment was to evaluate efficiency of application of biochar pellet in case of application of soil carbon sequestration technology. The treatments were consisted of control as general agricultural practice method, pellet(100% pig compost), biochar pellets with mixture ratio of pig compost(9:1, 8:2, 6:4, 4:6, 2:8) for comparatives of pH, EC, $NH_4-N$ and $NO_3-N$ concentrations, and yields in the nursery bed applied biochar pellets after lettuce harvesting. The application rates of biochar pellet was 6.6g/pot regardless of their mixed rates based on recommended amount of application (330kg/10a) for lettuce cultivation. pH in the nursery bed applied different biochar pellets after lettuce harvesting was only increased in the treatment plot of pig compost pellet application, but decreased in 4:6 and 2:8 pellet application plots. However, EC was observed to be not significantly different among the treatments. $NH_4-N$ concentration was only increased in the treatment plot of pig compost pellet application, but $NO_3-N$ concentrations were decreased as compared to the control. Yields in the treatments of 9:1, 8:2 and 4:6 biochar pellet application plot were increased from 9.5% to 11.4%. Therefore, this biochar pellet application might be useful for soil carbon sequestration and greenhouse gas mitigation in the agricultural farming practices because it was appeared to be a positive effect on lettuce growth.

• KDI Journal of Economic Policy
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• v.14 no.1
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• pp.61-87
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• 1992

Reducing the level of greenhouse gas emissions is necessary to mitigate global warming. One of the most feasible methods to reduce emissions would be to conserve energy and substitute fossil fuels. Yet reducing emissions entails huge financial costs, so it is advisable to employ cost-effective economic instruments such as a carbon tax or tradeable emissions permits. Assuming that the proper economic tools will be used in the future, we calculated the optimal level of emissions reduction for Korea. We applied to our cost-benefit analysis Nordhaus' scenario regarding the economic damage from a $3^{\circ}C$ rise in global temperatures, which is the calculated result when the greenhouse gas level doubles. The result of our analysis based on the 1990 data indicates that the optimal level of emissions reduction ranges from 2% to 15 % of current emissions depending on the value of damage parameters. We also found that the amount of emissions must be reduced will increase if action is postponed, when the development of climate engineering technology or more efficient use of energy is expected. In addition, we discussed the advantages and disadvantages of the economic instruments available to implement emissions reduction. Tradeable permits and carbon tax are equivalent in their cost-effectiveness, but have different implications in practice.

• Journal of radiological science and technology
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• v.26 no.1
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• pp.83-89
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• 2003

The accurate measurement of the femoral anteversion is very important to the practice of orthopedic and osteotomy. It is measured by means of the axis of head and neck of the femur and the knee axis. At the present time, widely used computed tomography method of measuring anteversion on femoral necks of patients. Measurement by the manual method and image viewer of computed tomography to determine the anteversion of femoral head were carried out on both femurs. In September and October 2002, 5 patients 28 to 36 years of age were randomly selected from Seoul National University Hospital. The purpose of this paper was to introduce a new method to measure femoral anteversion angle utilizing PACS image viewer program in the MR imaging. Significant difference was observed between the right and left side the image viewer measurement of femoral anteversion. In conclusion, MR imaging very usefulness in the measured the angle of the femoral anteversion.

• The Journal of Korean Academy of Sensory Integration
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• v.13 no.1
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• pp.45-56
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• 2015

Purpose : This study aimed to critically analyze published research papers in Journal of Korean Academy of Sensory Integration and to investigate the research field and trends. Methods : Types of studies, research trends, levels of evidence, participants, funding sources and research areas were analyzed and described by using 97 selected studies published between 2003 and 2014. Results : Every 5 years, the most frequent type of study was experimental research. The numbers of experimental studies and review studies have been increasing. The most frequent level of evidence was one group non-randomized study, followed by case reports. The highest percentage of participants were children with disability and the most common diagnoses were pervasive developmental disorder, developmental delay and intellectual disabilities. Most of the participants was elementary school students and the most frequent sample size was below 10. The percentage of research grant from Korean Academy of Sensory Integration has been over 50% since 2008. The research areas focusing on the standardized assessments were mostly sensory modulation, interaction and development and the non-standardized assessments were behavior observation and clinical observation. Conclusion : Higher level of studies and comprehensive research methods will be needed. The standardized assessment tools with the high sensibility on sensory integration which developed in the domestic need to be developed. Thus, it will be able to contribute to the evidence based practice in occupational therapy.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.3 no.4
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• pp.11-20
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• 1983

This study investigates reliability based design criteria for the spiral R.C. columns, and proposes practical algorithm which is based on Ellingwood's algorithm for the reliability analysis and the derivation of reliability based design criteria. Cornell's MFOSM theory is used for the derivation of the algorithm for the evaluation of uncertainties associated with resistances, whereas the magnitude of the uncertainties associated with load effects are chosen primarily by considering our level of practice. And thus the uncertainties so obtained are applied for the relilability analysis and the derivation of reliability based design criteria. A target reliability (${\beta}_0=3.5$) is selected as an appropriate value by comparing the values used in foreign countries and by analyzing, the reliability levels of our current USD and WSD design standards. Then, a set of load and resistance factors corresponding to the target reliability is proposed as a reliability based design provision, and furthermore a set of allowable stresses for reinforcing steel and concrete having same level of reliability with the corresponding LRFD criteria is also propared for the current WSD design provision. It may be concluded that the proposed LRFD reliability based design provisions and the corresponding allowable stresses give more rational design than the current code for spiral R.C. columns.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.37 no.2
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• pp.277-287
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• 2017

This paper describes the specifications on balanced steel ratio and maximum reinforcement for the design of RC flexural members by the Korean Highway Bridge Design Code based on limit states design. The Korean Highway Bridge Design Code (Limit States Design) is not provide for the balanced steel ratio specification for the calculation of required steel area of RC flexural members design. The maximum steel area limited the depth of the neutral axis at the ultimate limit states after redistribution of the moment, and also recommended the maximum steel area should not exceed 4 percent of the cross sectional area. However, from the maximum neutral axis depth provisions should increase the cross section is calculated to be less the maximum reinforcement area, and according to the 4% of the cross sectional area of the concrete, the tensile strain of the reinforcement is calculated to be greater than double the yielding strain, so can not guarantee a ductile behavior. This study developed a balanced reinforcement ratio that is basis for the required reinforcement calculation for tension-controlled RC flexural members design in the ultimate limit states verification provisons and material properties and applied the ultimate strain of the concrete compressive strength with a simple formular to be applied to design practice induced. And assumed the minimum allowable tensile strain of reinforcement double the yielding strain, and applying correction coefficient up to the ratio of maximum neutral axis depth, proposed maximum steel ratio that can be applied irrespective of the reinforcement yield strength and concrete compressive strength.

• Geophysics and Geophysical Exploration
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• v.13 no.3
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• pp.219-226
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• 2010

Current earthquake alert notification for immediate post-earthquake procedures for the critical facilities is exclusively dependent on the ground-motion intensity measures observed at the seismic station located within the site. This practice is prune to false notification due to a noise and problems of missing and poor quality records of the seismic station. The credibility of the earthquake alert notification can be enhanced by utilizing the multiple transformed records of the nearby seismic stations at other sites interconnected to the same earthquake monitoring system by a network. The time-domain transformation of the site-response between the seismic stations is implemented by convoluting the nearby records with a pair of forward and inverse FIR filters designed for the site response relative to a seismic basement. The transformed records from the nearby seismic stations can be used to estimate the ground-motion intensity measures missing at the site or to evaluate the data quality along with other various possible applications in the area of geoscience and earthquake engineering.

• Nutrition Research and Practice
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• v.4 no.6
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• pp.486-491
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• 2010

Tight control of blood glucose is the most important strategy for the treatment of diabetes mellitus. Here, we investigated the beneficial effects of Welsh onion on fasting and postprandial hyperglycemia. Inhibitory activities of hot water extracts from the green stalk and white bulb, which are the edible portions of the Welsh onion, and the fibrous root extract against yeast ${\alpha}$-glucosidase were measured in vitro. To study the effects of Welsh onion on postprandial hyperglycemia, a starch solution (1 g/kg) with and without Welsh onion fibrous root extract (500 mg/kg) or acarbose (50 mg/kg) was administered to streptozotocin-induced diabetic rats after an overnight fast. Postprandial plasma glucose levels were measured and incremental areas under the response curve were calculated. To study the hypoglycemic effects of chronic feeding of Welsh onion, five-week-old db/db mice were fed an AIN-93G diet or a diet containing either Welsh onion fibrous root extract at 0.5% or acarbose at 0.05% for 7 weeks after 1 week of adaptation. Fasting plasma glucose and blood glycated hemoglobin were measured. Compared to the extract from the edible portions of Welsh onion, the fibrous root extract showed stronger inhibition against yeast ${\alpha}$-glucosidase, with an $IC_{50}$ of 239 ${\mu}g/mL$. Oral administration of Welsh onion fibrous root extract (500 mg/kg) and acarbose (50 mg/kg) significantly decreased incremental plasma glucose levels 30-120 min after oral ingestion of starch as well as the area under the postprandial glucose response curve, compared to the control group (P < 0.01). The plasma glucose and blood glycated hemoglobin levels of the Welsh onion group were significantly lower than those of the control group (P < 0.01), and were not significantly different from those fed acarbose. Thus, we conclude that the fibrous root of Welsh onion is effective in controlling hyperglycemia in animal models of diabetes mellitus.