• Journal of the Korean Geosynthetics Society
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• v.9 no.4
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• pp.57-66
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• 2010

This study is described in heavy metal pollution by the stony mountain development using field case. The heavy metal pollution is investigated for nearby area (soil and stream) of the developed stony mountain, and then the countermeasure using contamination analysis is suggested. The investigation result indicated that contamination of Sammak stream caused by the stone dust and leachate at the stony mountain development. Therefore, the heavy metal pollution is evaluated by using Pollution Index(PI). The evaluation results confirmed that the contaminated groundwater was the leading cause of the contamination in Sammak stream and nearby soil. Therefore, the Permeable Reaction Barrier(PRB), which has a environmentally-friendly reactant, should be applied to control a heavy metal of groundwater, and it will be a reasonable countermeasure.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.28 no.3
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• pp.241-248
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• 2015

There are a lot of equipment related to safety and electric power production in nuclear power plants. The structure and equipment in NPPs were generally designed considering a high safety factor to remain in the elastic zone under earthquake load. However it is needed to revaluate the seismic capacity of the structure and equipment as the magnitude of earthquake was recently increased. In this study the floor response due to the nonlinear behaviors of structure was analyzed and the inelastic structural response factor was calculated by the nonlinear time history analysis. The inelastic structural response factor was calculated by the EPRI method and the nonlinear analysis method to realistically evaluate the seismic fragility for the equipment. According to the analysis result, it was represented that the inelastic structural response factor was affected by the natural frequency of equipment, the location of equipment and the dynamic property of structure.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.5 no.2 s.10
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• pp.29-43
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• 2006

Highway ARS service made several times handling of cellular phone for accept the one information. But, use the cellular phone while driving is against the law that 'Road Traffic Act' and wield influence on safety by degrade driver's attention that causes reduced section of concentration. On this study, propose a new type service that more useful and safer witch improved of existing ARS service to it served for cellular phone. For the analyze problem in existing ARS service, collect and analysis that ARS using status data and highway overall speed data, and then offer a better service type which based on improvements to that. Also, make a comparative analysis including measure of degree about easy to use and safety between two services by using the Stated Preference method, as a result of verifies the effect of new type service Finally, for measure of the effect the value of improved ARS service type that used willingness to pay in CVM method.

• Journal of the Korean Society of Marine Environment & Safety
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• v.22 no.1
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• pp.67-73
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• 2016

This study analyzed the state of the vessels which were using the berth for dangerous goods more than its carrying capacity in the major dangerous cargo handling port of Ulsan in Korea, The result of the analysis showed that a ship which has 3 times more than the maximum berthing capacity was moored at berth. Accordingly, a simulation model for 50,000 DWT berth was built and carried out the mooring safety analysis with 50,000 DWT, 70,000 DWT and 100,000 DWT vessels by mooring assessment program. The evaluation was carried out according to the standard environment presented in OCIMF standards. 50,000 DWT vessel was evaluated to meet the acceptable criteria but, 70,000 DWT and 100,000 DWT vessels exceeded the acceptable limit as per external conditions. Consequently, safe mooring guidelines were suggested and also proposed the building of common 'Mooring safety guideline' for port with assessment of different cases.

• Journal of the Korean Society for Library and Information Science
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• v.39 no.1
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• pp.221-239
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• 2005

This Paper assesses the relative efficiency of public library services by examining the relationship between library inputs and library outputs in library systems. Using Data Envelopment Analysis, this study derives efficiency scores in the provision of library services for 21 public libraries in Seoul. The data are survey observations for 2002. We employ total holdings, total serials, and total acquisitions as inputs, and total circulations and reader visits as outputs. The result shows that the subject libraries operate at just $71\%$ efficiency, i.e., inputs could be reduced by one-three without sacrificing output if all libraries were as efficient as the benchmark 4 identified by DEA. Too many total collections are the main source of inefficiency.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.37 no.1
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• pp.231-238
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• 2017

Water supply safety index plays an important role on assessing the water supply capacity of hydrologic system. Due to the absence of consistent guidance, however, practical problems have been brought up on data period used for dam design and performance evaluation. Therefore, this study employed bivariate drought frequency analysis which is able to consider drought severity and duration simultaneously, in order to evaluate water supply capacity of multi-purpose dams. Drought characteristics were analyzed based on the probabilistic approach, and water supply capacity of five multi-purpose dams in Korea (Soyang River, Chungju, Andong, Daecheong, Seomjin River) were evaluated under the specific drought conditions. As a result, it would be possible to have stable water supply with their own inflow during summer and fall, whereas water shortage would occur even under the 1-year return period drought event during spring and winter due to low rainfall.

• Journal of Digital Convergence
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• v.15 no.7
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• pp.359-365
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• 2017

This study was conducted structural model analysis focusing on the factors influencing UHDTV service usage. The perceived quality, innovativeness, price sensitivity are adopted as independent variables and perceived usefulness, perceived easy use are adopted as intervening variables. Especially symbolism used it as a control variable. As a result of the analysis by PLS, the influence coefficient of perceived quality was significantly higher than other variables. However, the combined effect of symbolism and perceived quality has a negative effect on perceived usefulness, and the more the users consider the symbolism of UHDTV usage, the more negative the evaluation of UHD quality and usefulness. With the launch of the terrestrial UHDTV service in May 2017, the most important issue is the production and distribution of high-quality content that users want.

• Tunnel and Underground Space
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• v.20 no.6
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• pp.446-454
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• 2010

CAES-G/T (Compressed Air Energy Storage - Gas Turbine) power generation is a likely option for the buffer facility stabilizing the fluctuation of the renewable powers, such as wind and solar powers. Considering the geological conditions, the underground CAES facility is most probable if the CAES-G/T generation is planed in Korea. In this kind of facility, a concrete plug is installed to seal the compressed air in the container, so that the selection of the shape and dimension of concrete plug could be a critical design factor. The stability evaluation of two types of plug was carried out by investigating the distribution of the factor of safety in the plugs and the distribution of contact pressure over the contact surface. The analysis result shows that the taper-shaped plug is more structurally stable than the wedge-shaped plug for the given geological condition. Possible separation of the rock-concrete interface around the spring line of the wedge-shaped plug is anticipated, which means the possible leakage of compressed air through the side wall and also means the poor mobilization of frictional resistance on that area.

• Physical Therapy Rehabilitation Science
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• v.7 no.2
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• pp.54-60
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• 2018

Objective: Persons with chronic stroke fall more often than healthy elderly individuals. The Timed Up and Go test (TUG) is used as a fall prediction tool, but only provides a result for the total measurement time. This study aimed to determine the optimal cut-off values for each of the 6 components of the TUG. Design: Retrospective study. Methods: Thirty persons with chronic stroke participated in the study. TUG evaluation was performed using a wearable miniaturized inertial sensor. Sensitivity, specificity, and predictive values were calculated using the Receiver Operating Characteristic (ROC) curve analysis for the measured values in each section. Optimal values for fall risk classification were determined. Logistic regression analysis was used to investigate the risk of future falls based on TUG. Results: The cut-off values of the 6 sections of the TUG were determined, as follows: sit-to-stand >2.00 seconds (p<0.05), forward gait >4.68 seconds (p<0.05), mid-turn >3.82 seconds (p<0.05), return gait >4.81 seconds (p<0.05), end-turn >2.95 seconds (p<0.05), and stand-to-sit >2.13 seconds (p<0.05). The risk of falling increased by 2.278 times when the mid-turn value was >3.82 seconds (p<0.05). Conclusions: The risk of falls increased by 2.28 times when the value of the mid-turn interval exceeded 3.82 seconds. Therefore, when interpreting TUG results, the predictive accuracy for falls will be higher when the measurement time for each section is analyzed, together with the total time for TUG.

• Journal of the Korea institute for structural maintenance and inspection
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• v.25 no.4
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• pp.20-27
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• 2021

The present study presents a nonlinear finite element analysis (FEA) approach using the general program of Abaqus to evaluate the seismic response of unreinforced masonry walls strengthened with the steel bar truss system developed in the previous investigation. For finite element models of masonry walls, the concrete damaged plasticity (CDP) and meso-scale methods were considered on the basis of the stress-strain relationships under compression and tension and shear friction-slip relationship of masonry prisms proposed by Yang et al. in order to formulate the interface characteristics between brick elements and mortars. The predictions obtained from the FEA approach were compared with test results under different design parameters; as a result, a good agreement could be observed with respect to the crack propagation, failure mode, rocking strength, peak strength, and lateral load-displacement relationship of masonry walls. Thus, it can be stated that the proposed FEA approach shows a good potential for designing the seismic strengthening of masonry walls.