• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.16 no.1
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• pp.166-175
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• 2017

Hazardous volcanic activity will continue to occur in the ring of fire, a major area in the basin of the Pacific Ocean where a large number of earthquakes and volcanic eruptions occur. and, because of rising populations, development pressures, and expanding national and international air traffic over volcanic regions, risks to life and property through exposure to volcano hazards continue to increase. During an eruption, volcanic contamination can reach and exceed the cruising altitudes of turbine-powered aircraft, among others, within minutes and spread over vast geographical areas within a few days. Volcanic ash can affect the operation of aircraft at aerodromes. Volcanic ash deposition at an aerodrome, even in very small amounts, can result in the closure of the aerodrome until all the deposited ash has been removed. In this study, air traffic information framework is presented along with algorithms to define affected routes, waypoints and airports using GIS geometry analysis.

• Journal of the Korean Recycled Construction Resources Institute
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• v.3 no.1
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• pp.72-83
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• 2015

Underground transmission lines always generate heat and transmit heat through surrounding backfill materials. Therefore, in the design of power lines it becomes a very crucial factor to transfer heat effectively into the neighbouring soils. In this study, in order to enhance field applicability of recycled aggregates for backfill material of transmission lines, quality criteria and construction criteria were proposed, and thermal stability of power lines through field demonstration tests were analyzed. In the field tests, two types of recycled aggregates and sand which is currently used for backfilling were compared in terms of thermal behaviour. Test results showed that recycled aggregates represented similar trends with sand in temperature and moisture content corresponding to time lapse and distance from the heat source. Consequently, recycled aggregates can be utilized for backfill materials of underground transmission lines as a substitute material of sands.

• Journal of Korean Tunnelling and Underground Space Association
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• v.20 no.5
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• pp.773-786
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• 2018

In this paper, viscosity features of sealant (bentonite-cement slurry), which is used for umbrella arch method in tunnel, were studied. The sealant must secure optimal strength and capacity for the waterproof and stabilization of borehole as well as to satisfy groutability. In this study, the variation of viscosity was measured with different mixing processes. With an increase of initial mixing period with water and bentonite mixture, the required time for the rapid increase of viscosity of the sealant is shorten. With increase of mixing period, the possibility of swelling of bentonite will increases and this can lead increase of the viscosity of the mixture. In addition, the behaviors of sealant vary with a drastic increase of the viscosity: thixotropy and rheopexy. Furthermore, the bentonite/water mixing period influences on the bleeding features of the sealant. Further study is required to introduce the guideline, which can be applicable in the field in the aspect of required capacity of the sealants and mixing processes of the ingredients.

• Journal of the Korean Electrochemical Society
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• v.5 no.2
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• pp.74-78
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• 2002

Zinc Air battery obtain their energy density advantage over the other batteries by utilizing ambient oxygen as the cathode materials, and reusing cathode as recycled form. And specific capacity of zinc powder is as high as 820 mAh/g. However, if the pore size in cathode is small then the flow rate of air decreased, and as a result of that discharge voltage of batteries becomes low. We focused on resistance and porosity of cathode. So we studied the effects of conducting agents to zinc air batteries performance, capacity, power density, average discharge voltage, resistance. And we also measured porosity of cathode by the ASTM. So we have got optimum contents of conducting agent.

• Proceedings of the Korea Concrete Institute Conference
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• 2008.04a
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• pp.169-172
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• 2008

Carbon fiber reinforced polymer (CFRP) laminates can be used more efficiently in strengthening applications by applying prestress to the CFRP laminates. A key problem for prestressing with CFRP laminates is anchoring the laminates. These may include fracture to the CFRP laminates due to excessive gripping force or slippage of the CFRP laminates out of the anchorage zone caused by low friction between the anchor device and the lamiantes. The main objective of this study is the development of an applicative mold-type anchorage system for prestressed CFRP laminates through experimental study. The experimental parameters were the type of anchorage detail and the effect of surface treatment. The test results showed that the developed anchor assures 100% CFRP laminate strength.

• Journal of the Korea institute for structural maintenance and inspection
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• v.14 no.2
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• pp.121-127
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• 2010

An experimental study of composite beam with perforated fiber reinforced polymer(FRP) plank as a permanent formwork and the tensile reinforcement was performed. A combined formwork and reinforcement system can facilitate rapid construction of concrete members since no conventional formwork is needed, which requires time consuming assembly and dismantling. In order for a smooth FRP plank to act compositely with the concrete, the surface of the FRP needs to be treated to increase its bond properties. Aggregates were bonded to the FRP plank using a commercially available epoxy and perforated web of plank. No additional flexural or shear reinforcement was provided in the beams. For comparison, two control specimens were tested. One control had no perforated hole in the web of FRP plank and the other had internal steel reinforcing bars instead of the FRP plank. The beams were loaded by central patch load to their ultimate capacity. This study demonstrates that the perforated FRP plank has the potential to serve as a permanent formwork and reinforcing for concrete beam.

• KOREAN JOURNAL OF PACKAGING SCIENCE & TECHNOLOGY
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• v.19 no.1
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• pp.1-6
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• 2013

Confectionary and food products were collected from Korea and Japan. Types of packaging structure, amount of packaging materials used, basis weight of paperboard, and product to packaging ratio were evaluated for understanding confectionery and food packaging in both countries. Also, new packaging samples were designed and fabricated for reducing the use of packaging resources and for optimizing the product to packaging ratio. Korean confectionary products showed much higher empty space inside package than that of Japanese products, while food products were not significantly different between tow countries. There were no significant differences in the basis weight of paperboard collected. All of the re-designed confectionary products showed more than 15% saving in packaging resource compared to current confectionary products.

• Journal of the Korean Recycled Construction Resources Institute
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• v.9 no.3
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• pp.367-374
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• 2021

In this study, the applicability of mechanochemical process for the manufacture of self-healing admixtures and the effect of mechanochemical process on the self-healing performance were evaluated. The self-healing admixtures were adopted as a highly reactive materials(expansive agent, swelling material and crystal growth agent) for mechanochemical processes. The self-healing admixtures for the mechanochemical process application were evaluated by X-Ray Diffraction and Fourier Transform Infrared Spectroscopy analysis, water permeability performance was used to evaluate self-healing performance of mortar. As a result of the evaluation, the self-healing performance of the WM(With-Mortar)3 sample to which mechanochemical process increased by 4.1% compared to the WM1 sample that was not treated, and the average healing index was 94.3%.

• The Journal of Bigdata
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• v.5 no.2
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• pp.43-52
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• 2020

With the development of data technology, storing and sharing of data has increased, resulting in privacy invasion. Although de-identification technology has been introduced to solve this problem, it has been proved many times that identifying individuals using de-identified data is possible. Even if it cannot be completely safe, sufficient de-identification is necessary. But current laws and regulations do not quantitatively specify the degree of how much de-identification should be performed. In this paper, we propose an appropriate de-identification criterion considering the time required for re-identification. We focused on the case of using the k-anonymity model among various privacy models. We analyzed the time taken to re-identify data according to the change in the k value. We used a re-identification method based on linkability. As a result of the analysis, we determined which k value is appropriate. If the generalized model can be developed by results of this paper, the model can be used to define the appropriate level of de-identification in various laws and regulations.

• Proceedings of the Plant Resources Society of Korea Conference
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• 2022.09a
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• pp.65-65
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• 2022

지속가능한 DMZ 일원의 생태복원 추진을 위해 DMZ 생태교란지에서 복원공법 모니터링을 실시하였다. 본 실험은 강원도 인제군, 철원군 및 경기도 연천군의 DMZ 내(450m²)에서 진행되었으며, 흰민들레, 구절초, 매발톱, 질경이, 꿀풀이 공시식물로 사용되었다. 각 대상지의 식생유형별 시공방법에 따른 침입종 억제효과를 알아보기 위해 2022년 4월부터 9월까지 일반식생기반재와 특수식생기반재로 처리된 실험구의 전체 피도, 도입종 피도, 침입종 피도, 초장, 출현종 등을 측정하였다. 전체 피도는 세 곳 모두 일반 기반재보다 특수기반재에서 더 높게 나타났으나 대상지에 따라 침입종 피도가 미치는 영향은 달랐다. 도입종의 피도는 인제, 철원, 연천에서 동일하게 흰민들레가 가장 높은 수치를 보였고, 특수기반재에서 보다 높은 피도를 보였다. 폭염 및 폭우로 6월 이후 흰민들레가 감소하면서 구절초, 매발톱의 피도가 점차 증가하였으며 기반재 간의 큰 차이는 없었으나 일부 지역에서는 구절초 피도가 특수기반재보다 일반기반재에서 더 높게 나타났다. 또한, 모든 지역에서 질경이와 꿀풀의 생장은 미미하였다. 같은 처리를 했음에도 대상지별로 소재식물의 출현 여부, 생장률, 침입종의 피도 등이 다른 것으로 보아 복원지의 환경 여건에 따라 적용해야 하는 종, 시공방법, 주변 완충지역의 범위 등에 차이를 두어야 할 것으로 보인다.