• Journal of the Korea Academia-Industrial cooperation Society
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• v.19 no.3
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• pp.542-552
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• 2018

In this paper, the precast method of a concrete eco-pillar debris barrier was proposed to improve the construct ability and economic efficiency. The performance was validated by experimental and structural analysis. The steel debris barrier has a high construction cost and causes environmental damage with corrosion. The construction of a concrete eco-pillar debris barrier has been increased recently. On the other hand, there are no design standards regarding debris barriers in Korea, and debris barriers are being designed by the experience and sense of engineers. Therefore, in this study, a method to determine the design external forces was proposed and the design was performed by applying a hollow cross-section to the debris barrier. In addition, three types of connection methods of a concrete cantilever column with the maximum bending moment acts were proposed, and validation of the performance of each type was performed with a real-scale experiment. The experimental results showed that the type with loop reinforcement had the highest rigidity and the type with anchorage performance exceeded the maximum bending moment according to the ultimate load. In the manufacturing procedure of mock-up debris barriers, the type with an anchorage-bar was found to have superior construct ability.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.21 no.11
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• pp.602-609
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• 2020

In the event of a large-scale disaster such as an earthquake, typhoon, landslide, and building collapse, the disaster situation awareness and timely disaster information sharing play a key role in the disaster response and decision-making stages for disaster management, such as disaster site control and evacuation of residents. In this paper, an exited field investigation system of NDMI (National Disaster Management Research Institute) was enhanced with an LTE-VPN- based wireless communication system to provide an effective on-site response in an urgent disaster situation and share observation data or analysis information acquired at the disaster fields in real-time. The required performance of wireless communication for the disaster field investigation system was then analyzed and evaluated. The experimental result for field data transmission performance of an advanced wireless communication investigation system showed that the UDP transmission performance of at least 4.1Mbps is required to ensure a seamless video conference system between disaster sites. In addition, a wireless communication bandwidth of approximately 10 Mbps should be guaranteed to smoothly share the communication and field data between the survey equipment currently mounted on the survey vehicle.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.15 no.12
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• pp.2712-2716
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• 2011

The development of mobile phone is growing everyday according to the change of our age. Most of all, the birth of smart phone has gotten lots of attentions. The Smart Phone has not only nalogue functions for calling and receiving but also has many multiple-service functions satisfying the contemporary digital needs. Due to the smart phone, people could access to various and plenty information simply by touching it. It was Sep. 2011 that the number of smart phone users began to be more than 15,000,000. That number stands for the turning point of digital revolution. In Korea, both of "Omnia" from Samsung and "i-phone" from Apple came into the market near the end of 2009. That time was so called the full-scale first smart-phone war, and thinking of the time, it could be named as the explosive growth of smart phones. We can predict that the smart phone will influence the real life of human beings not only the mobile phone market. In this way, the smart phone has come deeply into our life day by day. For instance, more people can be able to get the informations of their trip for their leisure and free weekends through the smart phone. Thus, our study, began with the theme of "Korean islands trip", will start in the relationship with the Application-Services, "Islands" utilizing web-pictures.

• Journal of Preventive Medicine and Public Health
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• v.28 no.3 s.51
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• pp.623-639
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• 1995

We have never seen any method to cope basically with complicated situation and problems around medical reimbursement rates here in Korea since 1977 witnessed by the beginning of medical insurance. By the way researchers concerned are beginning to propose some kinds of innovative and detailed ideas to government these days. They are Diagnosis-related group(DRG) and Resource-based .elative value scale(RBRVS). In the light of this situation it is so encouraging that our government can come up with that and move. In case of RBRVS research we have already been reaching even to the level of reviewing and revising methodology for its further development after naive pilot study on internal medicine and general surgery last year. However there might be something different conditions between USA and Korea to apply the same Dr. Hsiao's method and it must be vital to check so called' total work approach' compared with 'intra-service work approach' before expanding to the whole medical fields. According to the' Intra-service approach', the physician's work is supposed to be divided into three sub-works by the name of intraservice work, pre, and post service work. These sub-works, again should be merged together to be the pre-postwork subset through some statistical methods of the estimation process applied by Dr. Hsiao's methodology in RBRVS development later on. But in this paper that estimation process was not taken because we could have real values for all of those surveyed items related to just one specialty, OB & GY. Instead, We used some statistical comparison procedures relevant to demographic characteristics, reliability & validity and correlation analysis with American RVU(Relative value unit) between the total work and merged total work from intraservice work approach. The unit of analysis was individual physicians of OB & GY and 300 physicians were selected for each approach through statistical sampling method based on national population of OB & GY physicians in Korea. And also with the thankful help of Advisory Committee under Korean Association of OB & GY, questionnaires were made and mailed to the subjects, two times. As a result there were not any statistically significant differences in demographic characteristics between the two approaches except for the variable 'Response time for the questionnaires', but in other sections of comparisons, response rate, representative values, reliability & validity test, correlation analysis with American RVU, all showed 'Total approach' was not only more rational and statistically meaningful than 'Intra-service approach' but also had considerable merits. But we are not absolutely sure about this paper's robustness. Because of some limitations, we'd rather like to suggest further researches should be followed. In that sense the first thing would be a research for the influence of doctor's characteristics, especially 'frequency' on the rating of work and the way to define total work more clearly.

• Economic and Environmental Geology
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• v.50 no.2
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• pp.159-170
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• 2017

The temporal and spatial temperature distribution of the heat storage mortar made of porous feldspar was measured and the thermal properties and electricity consumption were analyzed. For the experiment, two real size chambers (control model and test model) with hot water pipes were constructed. Two large scale models with hot water pipes were constructed. The surface temperature change of the heat storage layer was remotely monitored during the heating and cooling process using infrared thermal imaging camera and temperature sensor. The temperature increased from $20^{\circ}C$ to $30^{\circ}C$ under the heating condition. The temperature of the heat storage layer of the test model was $2.0-3.5^{\circ}C$ higher than the control model and the time to reach the target temperature was shortened. As the distance from the hot water pipe increased, the temperature gap increased from $4.0^{\circ}C$ to $4.8^{\circ}C$. The power consumed until the surface temperature of the heat storage layer reached $30^{\circ}C$ was 2.2 times that of the control model. From the heating experiment, the stepwise temperature and electricity consumption were calculated, and the electricity consumption of the heat storage layer of the test model was reduced by 66%. In the cooling experiment, the surface temperature of the heat storage layer of the test model was maintained $2^{\circ}C$ higher than that of the control model. The heat storage effect of the porous feldspar mortar was confirmed by the temperature experiment. With considering that the time to reheat the heat storage layer is extended, the energy efficiency will be increased.

• Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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• v.4 no.1
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• pp.9-15
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• 2006

For the accurate safety assessment of potential radioactive waste disposal site which is located in the crystalline rock it is important to simulate the mass transportation through engineered and natural barrier system precisely, characterized by porous and fractured media respectively. In this work the methods to construct discrete fracture network for the analysis of flow and mass transport through fractured-porous medium are described. The probability density function is adopted in generating fracture properties for the realistic representation of real fractured rock. In order to investigate the intersection between a porous and a fractured medium described by a 2 dimensional rectangular and a cuboid grid respectively, an additional imaginary fracture is adopted at the face of a porous medium intersected by a fracture. In order to construct large scale flow paths an effective method to find interconnected fractures and algorithms of swift detecting connectivities between fractures or porous medium and fractures are proposed. These methods are expected to contribute to the development of numerical program for the simulation of radioactive nuclide transport through fractured-porous medium from radioactive waste disposal site.

• The Journal of Engineering Geology
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• v.25 no.1
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• pp.83-91
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• 2015

Few studies have investigated soil management policy and soil erosion measurement, whereas the occurrence of climate change requires the establishment of robust soil management systems and appropriate control of soil erosion. In this study, we developed a smart sensor for real-time quantitative measurements of soil erosion at the watershed scale. The smart sensor consists of an ultrasonic sensor, a rainfall meter, a solar cell, an RTU (remote terminal unit),and a CDMA (code division multiple access) and it was programmed to take a measurement every 30 minutes. The depths measured by the smart sensor were compared with data from terrestrial LiDAR. Experimental results showed a strong correlation in the depth of soil erosion between LiDAR and the ultrasonic sensor for the period from 22 August to 11 October 2013. Furthermore, the correlation coefficient between soil erosion depth (mm) and soil erosion volume (m³) was 0.9063 in the lower region of the watershed and is 0.9868 in the upper region. The proposed ultrasonic sensor technique can provide high-quality data for soil conservation and management systems in the future.

• The Journal of the Korea Contents Association
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• v.12 no.3
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• pp.233-243
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• 2012

The purpose of this study was to examine the effects of lumbar stabilization exercise using the PNF techniques on the lumbar deep muscles thickness and functional activity in chronic low back pain patient. Group I(n=10): general physical therapy group; Group II(n=10): general lumbar stabilization exercise group; Group III(n=10): lumbar stabilization exercise using PNF techniques(stabilizing reversal, rhythmic stabilization, combination of isotonic) group. Change of pain was measured with visual analog scale(VAS). To observe muscle thickness changes, we measured transverse abdominis(TrA), external oblique(EO), multifidus with real time ultrasound scanning. The functional activity were measured with Oswestry Disability Questionnaire(ODQ) and Roland & Morris Disability Questionnaire(RMDQ). In VAS test, group III had more significantly decreased than before exercise. In muscle thickness test, group III had more significantly increased than before exercise in right/left TrA, EO, multifidus. In ODQ & RMDQ test, group III had more significantly decreased than before exercise. This study show that the PNF techniques is effective in improving the lumbar stability and functional activity in chronic low back pain patients.

• Journal of the Korea Organic Resources Recycling Association
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• v.8 no.2
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• pp.102-113
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• 2000

This study was conducted to investigate the expandibility of sludge treatment by earthworm through real scale experiment and the optimum counter-plan for organic sludge treatment. For the purposes, sludge removal efficienciesof night-soil using earthworm and it's behavior according to the transplanting methods of the earthworm on non-cover worm bed or in the green house worm bed were compared. Sludge uptake rates on non-cover worm bed for 6 months were $0.27{\sim}0.33ton/m^2$ and the excrement of earthworm yields $0.15ton/m^2$(44.1~46.7% of raw night soil sludge dosage). These results were not much different from the worm bed in the green house. The average and maximum earthworm density were about $6.5kg/m^2$ and $7kg/m^2$ respectively on the non-cover worm bed. The density of the worm bed was comparatively higher in spring and fall terms but lower in summer. The amount of old earthworm was much plenty than young earthworm on the non-cover worm bed, resulting in reverse distribution type of pyramid. From the experiments on non-cover worm bed(7,000 pyeong)and in the green house worm bed(1,200 pyeong), it was concluded that landfill and transporting cost could be reduced when the earthworm was applied for the night-soil sludge treatment. Profits from the excrement sale of earthworm was 9,600,000 won. Through this study, it was founded that earthworm treatment method for organic sludge are much more environmentally sound than landfill treatment.

• Structural Monitoring and Maintenance
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• v.5 no.1
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• pp.151-171
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• 2018

Transmission tower-line systems are commonly slender and generally possess a small stiffness and low structural damping. They are prone to impulsive excitations induced by cable rupture and may experience strong vibration. Excessive deformation and vibration of a transmission tower-line system subjected to cable rupture may induce a local destruction and even failure event. A little work has yet been carried out to evaluate the performance of transmission tower-line systems in mountain areas subjected to cable rupture. In addition, the control for cable rupture induced vibration of a transmission tower-line system has not been systematically conducted. In this regard, the dynamic response analysis of a transmission tower-line system in mountain areas subjected to cable rupture is conducted. Furthermore, the feasibility of using viscous fluid dampers to suppress the cable rupture-induced vibration is also investigated. The three dimensional (3D) finite element (FE) model of a transmission tower-line system is first established and the mathematical model of a mountain is developed to describe the equivalent scale and configuration of a mountain. The model of a tower-line-mountain system is developed by taking a real transmission tower-line system constructed in China as an example. The mechanical model for the dynamic interaction between the ground and transmission lines is proposed and the mechanical model of a viscous fluid damper is also presented. The equations of motion of the transmission tower-line system subjected to cable rupture without/with viscous fluid dampers are established. The field measurement is carried out to verify the analytical FE model and determine the damping ratios of the example transmission tower-line system. The dynamic analysis of the tower-line system is carried out to investigate structural performance under cable rupture and the validity of the proposed control approach based on viscous fluid dampers is examined. The made observations demonstrate that cable rupture may induce strong structural vibration and the implementation of viscous fluid dampers with optimal parameters can effectively suppress structural responses.