• Journal of Korean Tunnelling and Underground Space Association
• /
• v.22 no.3
• /
• pp.261-275
• /
• 2020

When excavating a small cross-section tunnel in a fault fracture zone using the shield TBM method, there is a high possibility of excessive convergence and collapse. Appropriate ground reinforcement is required to minimize construction cost loss and trouble due to a fault fracture zone. In this study, the optimal reinforcement area was suggested and the surrounding ground behavior was investigated through numerical analysis using MIDAS GTS NX (Ver. 280). For the parameters, the width of the fault fracture zone, the existence of fault gouge, and the groundwater level and depth of cover were applied. As a result, when there is not fault gouge, the convergence and ground settlement are satisfied the standard when applying ground reinforcement by up to 0.5D. And, due to the high permeability coefficient, it is judged that it is necessary to apply 0.5D reinforcement. There is a fault gouge, it was possible to secure stability when applying ground reinforcement between the entire fault fracture zone from the top of the tunnel to 0.5D. And, because the groundwater discharge occurred within the standard value due to the fault gouge, reinforcement was unnecessary.

• Korean Security Journal
• /
• no.57
• /
• pp.137-156
• /
• 2018

The purpose of this study is to analyze the current status of counter terrorism system and to identify the causes of problems and to suggest alternatives by selecting legal and operational sectors based on theories of open systems and integrated systems. According to the results of the research, first, the degree of agreement on the open system and the integrated system is low with regard to the characteristics of the counter-terrorism system. Second, in relation to the importance and necessity of major factors of construction and operation of counter-terrorism system, counter-terrorism workers recognize that it is the most important and necessary. In the case of strengthening international cooperative system, the difference of recognition between importance and necessity was the biggest. The importance and necessity of reviewing the Anti-Terrorism Act for the protection of the public and public safety were relatively low, and the cooperation with the private sector showed the lowest importance and necessity. In the case of academic achievement, the average level of high school graduates is higher than that of professional high school graduates. Therefore, this research concludes that counter terrorism operation system with open and integrated system has to be applied to national counter terrorism operation structure in South Korea in increasing the quality and efficiency of nation counter terrorism response capability.

• Journal of the Korean Magnetics Society
• /
• v.24 no.1
• /
• pp.22-27
• /
• 2014

North indicating azimuth angle sensors have been used in airplanes, ships traditionally and nowadays employed in smart phones. For the azimuth and roll angle measurement of the sensor, 3-axis acceleration sensor was added to the 3-axis magnetic field sensor. In this work, we have constructed a measuring system for the measurement of the magnetic field and the angle uncertainty of the magnetic field sensors. Measuring system could be useful not only in non-magnetic laboratory but also in normal laboratory, we constructed small size of 3-axis Helmholtz coils for the compensation environment magnetic field (Earth magnetic field and magnetic field from building) and the generation of magnetic field for the test of magnetic field sensor. The constructed measuring system could compensate environment magnetic field below 10 nT level and generate 3-dimensional magnetic field with magnitude uncertainty of 0.2 % and angle error of $0.2^{\circ}$ within the volume of ${\pm}30mm$ diameter at center of Helmholtz coils. For the conformation of developed measuring system, We tested commercially available 3-axis magnetometer and heading sensor.

• Journal of Korean Tunnelling and Underground Space Association
• /
• v.24 no.6
• /
• pp.745-756
• /
• 2022

The road tunnel is a semi-closed space that is blocked on all sides except the entrance and exit, and in the event of a fire, the smoke of the fire spreads longitudinally due to heat buoyancy caused by the fire and air currents that always exist in the tunnel. To solve this problem, smoke removal facilities are installed in road tunnels to secure a safe evacuation environment by controlling the direction of movement of smoke or directly smoking at fire points. In urban areas, the service level of urban roads decreases due to the increase in traffic due to the increase in population, and as a solution, the construction of underground roads in urban areas is increasing. When a fire occurs during hydrogen leakage through TPRD of a hydrogen fuel cell vehicle (FCEV), the fire intensity depends on the amount of leakage, and the maximum fire intensity depends on the orifice diameter of the TPRD. Considering the TPRD orifice diameter of 1.8 mm, this study analyzed the diffusion distance of fire smoke according to the wind speed of the roadway and the opening interval of the large exhaust port when the maximum fire intensity was 15 MW. As a result, it was analyzed that air flow in the tunnel could be controlled if the wind speed of the road in the tunnel was less than 1.25 m/s, and smoke could be controlled within 200 m from the fire if the damper interval was 50 m and 100 m.

• Informatization Policy
• /
• v.28 no.3
• /
• pp.95-111
• /
• 2021

To achieve a data-driven policy decision-making system, the Ministry of Strategy and Finance has formed a marketing team and is actively building upon it. This system, currently under construction, will enable data-driven financial tasks beyond simple financial administration. The U.S. has already enacted The Foundations for Evidence-Based Policymaking Act in the process of similar pursuits. Since last year, the data-driven system administrative law has been enacted in Korea, and a legal framework has been established for data-driven administrative work. The next-generation budget accounting system to fulfill its role as a data-driven system needs public policy support to operate. Innovation and transformation are needed in various areas such as data management, legal system, and installation of related systems. Accordingly, it is very timely to analyze the financial systems and policies of advanced countries such as the U.S. and U.K., which already have established and operates such a financial system. By benchmarking and applying existing financial information systems to the next-generation budget accounting system, a better system will result. In this study, major developed countries, including the U.S., U.K., France, and Canada were benchmarked and analyzed in terms of the main elements of data governance: public policy, systems, legal framework, promotion system, and service level. It was discovered that the role and direction of the national fiscal policy system that the people favor should be able to respond quickly to the recent difficult economic crisis environment such as the digital transformation trend and COVID-19.

• Ecology and Resilient Infrastructure
• /
• v.8 no.3
• /
• pp.135-142
• /
• 2021

Biopolymers have been known as eco-friendly soil strengthening materials and studied to apply levees. However, the effect of biopolymer on vegetation is not fully understood. In this study, we analyzed the root growth of Camelina sativa L. (Camelina) when the xanthan gum was amended to soil in Aluminum (Al) stress conditions. Amendment of 0.05% xanthan gum increased root growth of Camelina under Al stress conditions. Under the Al stress condition, expression of aluminum activate malate transporter 1 (ALMT1) gene of Camelina root was induced but showed a lower level of expression in xanthan gum amended soil than non-amended soil. Additionally, the binding capacity of xanthan gum with Al ions in the solution was confirmed. Using morin staining and ICP-OES analysis, the Al content of the roots in the xanthan gum soil was lower than in the non-xanthan gum soil. These results suggest that xanthan gum amended soils may reduce the detrimental effects of Al on the roots and positively affect the growth of plants. Therefore, xanthan gum is not only an eco-friendly construction material but also can protect the roots in the disadvantageous environment of the plant.

• The Journal of The Korea Institute of Intelligent Transport Systems
• /
• v.18 no.2
• /
• pp.12-28
• /
• 2019

Road geometry is one of the many factors that cause crashes, but the effect on traffic accident depends on weather conditions even under the same road geometry. This study identifies the variables affecting the crash severity by matching the highway accident data and weather data for 14 years from 2001 to 2014. A hierarchical ordered Logit model is used to reflect the effects of road geometry and weather condition interactions on crash severity, as well as the correlation between individual crashes in a region. Among the hierarchical models, we apply a random intercept model including interaction variables between road geometry and weather condition and a random coefficient model including regional weather characteristics as upper-level variables. As a result, it is confirmed that the effects of toll, ramp, downhill slope of 3% or more, and concrete barrier on the crash severity vary depending on weather conditions. It also shows that the combined effects of road geometry and weather conditions may not be linear depending on rainfall or snowfall levels. Finally, we suggest safety improvement measures based on the results of this study, which are expected to reduce the severity of traffic accidents in the future.

• Journal of Korea Water Resources Association
• /
• v.51 no.12
• /
• pp.1181-1194
• /
• 2018

This study suggests a novel approach of estimating stream flow discharge using the Synthetic Aperture Radar (SAR) images taken from 2015 to 2017 by European Space Agency Sentinel-1 satellite. Fifteen small to medium sized rivers in the Han River basin were selected as study area, and the SAR satellite images and flow data from water level and flow observation system operated by the Korea Institute of Hydrological Survey were used for model construction. First, we apply the histogram matching technique to 12 SAR images that have undergone various preprocessing processes for error correction to make the brightness distribution of the images the same. Then, the flow estimation model was constructed by deriving the relationship between the area of the stream water body extracted using the threshold classification method and the in-situ flow data. As a result, we could construct a power function type flow estimation model at the fourteen study areas except for one station. The minimum, the mean, and the maximum coefficient of determination ($R^2$) of the models of at fourteen study areas were 0.30, 0.80, and 0.99, respectively.

• Korean Journal of Heritage: History & Science
• /
• v.50 no.3
• /
• pp.126-145
• /
• 2017

The Seokgaejae section is located along a timber access road and a driveway across Bonghwa County, North Gyeongsang Province, and Samcheog city, Gangwon Province. Its stratigraphic column shows all of the ten strata of the lower Paleozoic Taebaek Group, Joseon Supergroup. The Seokgaejae section is proved to be scientifically important. Thirty-eight domestic/international journal papers have been published on this early Paleozoic stratigraphic site, and many distinguished researchers over the world have visited the site. However, the section has never been considered to be designated as a national natural monument and was not included in the adjacent Gangwon Paleozoic National Geopark due to management or administrative issues. Although the Seokgaejae section sufficiently satisfies many of the national natural monument criteria, designation for the natural monument may not be justified because of the facts that the outcrop was artificially exposed by road construction; the chance of destruction of the outcrop is relatively few; demage on the outcrop to some extent does not impair the intrinsic value of the section; and the geomorphological/landscape value of the section is low. The application of the recently modified geological heritage assessment model to the Seokgaejae section shows very high scores on the scientific/educational, intrinsic, and functional values. Based on the improved geological heritage grade standard, the Seokgaejae section conforms to the national-level protection criteria. It is strongly recommended to manage the Seokgaejae section as a principal geosite by including it in the Gangwon Paleozoic National Geopark. This case study on the Seokgaejae section also suggests that the process of application and endorsement of a national geopark need further improvement. As well as the improvement of the system or policy related to geological heritages, further efforts of the experts in various fields of geoscience are required in order for other geological heritages not to be neglected from now on.

• Journal of The Korean Association For Science Education
• /
• v.39 no.3
• /
• pp.337-348
• /
• 2019

The purpose of this study is to examine epistemic thinking in middle school students in an argument-based inquiry science class. Participants of the study were 93 9th grade students from four classes of a middle school in a metropolitan city. Observations were made over one semester during which argument-based inquiry lessons on five subjects were conducted. Data was collected from argument-based inquiry activity worksheets and student questionnaires. After analysis of epistemic thinking in the written reflections, students were found to have the highest frequency of epistemic metacognitive skills, followed by epistemic cognition, epistemic metacognitive experience, and epistemic metacognitive knowledge. While investigating the effects of an argument-based inquiry science class on student epistemic thinking and after analysis of the reflections written for the first ABI activity and the fifth ABI activity, we found that all of the sub-elements of epistemic thinking have increased. The rate of growth for epistemic cognition is greatest, followed by epistemic metacognitive knowledge and epistemic metacognitive skills. Assessed for epistemic thinking, the level of epistemic thinking improved over the course of the argument-based inquiry science class. The results of the survey show that students actively participating and being recognized for their active participation in the argument-based inquiry science class are helpful in understanding scientific knowledge. Therefore, an argument-based inquiry science class is a teaching and learning program that allows students to understand and experience the epistemic nature of scientific knowledge and its construction through collaboration and agreement.