• Journal of the Korea institute for structural maintenance and inspection
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• v.23 no.4
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• pp.96-102
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• 2019

When GGBFS(Ground Granulated Blast Furnace Slag) with high blaine is incorporated in concrete, compressive strength in the initial period is improved, but several engineering problems arise such as heat of hydration and quality control. In this paper, compressive strength and durability performance of concrete with 3,000 Grade-low fineness slag are evaluated. Three conditions of concrete mixtures are considered considering workability, and the related durability tests are performed. Although the strength of concrete with 3,000 Grade slag is slightly lower than the OPC(Ordinary Portland Cement) concrete at the age of 28 days, but insignificant difference is observed in long-term compressive strength due to latent hydration activity. The durability performances in concrete with low fineness slag show that the resistances to carbonation and freezing/thawing action are slightly higher than those of concrete with high fineness slag, since reduced unit water content is considered in 3,000 Grade slag mixture. For the long-term age, the chloride diffusion coefficient of the 3000-grade slag mixture is reduced to 20% compared to the OPC mixture, and the excellent chloride resistance are evaluated. Compared with concrete with OPC and high fineness GGBFS, concrete with lower fineness GGBFS can keep reasonable workability and durability performance with reduced water content.

• Journal of Technology Innovation
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• v.21 no.2
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• pp.355-373
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• 2013

This research paper is to identify factors affecting the need for international cooperation in defense science and technology sector. This study set a new hypothesis based on the previous research in terms of the theory of transaction cost, knowledge-based and technology readiness level perspective. After setting a new hypothesis, the following facts were found. First, it showed that the greater the importance of defense technology also increases the need for international technology cooperation for its technology. Second, the relatively higher distance of technology comparing to the developed countries was the need for international technology cooperation to be bigger. Lastly, the relatively higher technology readiness level of technology showed the negative relationship with the need for international cooperation. This results showed that the international cooperation in defense science and technology was regarded as complementary to get their short knowledge. The results of these analyzes showed that the international defense cooperation should be push forward based on the level of technology comparing to the developed countries and the technology readiness level.

• Environmental and Resource Economics Review
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• v.14 no.2
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• pp.493-518
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• 2005

It has been taken for 10 years since Climate Change Convention could it be made. And Kyoto Protocol will come into force as an international law as from 16. Feb 2005. As based on it, Annex I countries will implement their mitigation projects on GHG reductions and press developing countries on GHG reduction target. Korea has not duty target on it yet. But it will be held a COP(Conference of Party) on negotiation for reduction target of second commitment period. If Korea has a real duty, Industry sector should reduce GHG emissions. Then Market mechanism will be need to introduce for this. This study started having a question "Is it possible to introduce emissions trading in Korea?". To solve the problem, this study analysed GHG emissions, marginal abatement cost, market price with 11 companies of industry (about 36% of Korea emissions). minus target is impossible to implement reduction target ver base year (2002). And emissions trading scheme also can't make the market without additional policy and measures. This study suggest that it is need to import credits and give a subsidy of government to encourage it. The imported credit can reduce the demand curve within the marginal abatement cost curves. But the effectiveness of credit is not the same as continually growth. As a result, Allowing 40% credit into emissions trading market is the best to reduce costs. However, a subsidy is the little bit difference. A subsidy make marginal abatement cost curves down for itself. Giving 30% for subsidy, it is the best. Considering both of importing credits and subsidy, it is the best effects in the reducing cost for company. especially 30% is the best effects respectively. This Study show that government wants to consider designing emissions trading, encourage participants competitiveness, and encourage the early action, government has to allow credit trading and give a subsidy to participants.

• Journal of Science Education
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• v.34 no.1
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• pp.140-154
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• 2010

The core of subject matter education is determined by the choice of subject matter taught to students and by the organization of content according to educational objectives. The purpose of this research is to suggest ways to improve the present content of science education so as to prepare students and schools for a radically different future. We deduced the main issues the solution of which could lead to significant improvements in the contents of science education by analyzing previous studies and investigating the changes in content that were effected during curriculum revisions in the past. The main issues thus revealed through this study are as follows: the essence of the contents of subject matters in science education, the social and cultural background of change in the science curriculum, the rational steps on the way to choosing contents as part of the science curriculum, the processes of choosing the main contents of each subject, the international comparative study of contents, the updating of contents for the benefit of future society, and the reorganization of subject contents. In order to find a concrete improvement on the issues deduced, we organized an expert group. Then, we proceeded to collect and analyze the experts' opinions. A survey was administered to 19 science education experts working with universities and colleges of education. We examined their degree of agreement on the issues and problems, and on the steps that may be taken to us the improvements on these issues. we suggested that: collecting opinion and reaching an agreement on the essence of the contents of the subject matters in science education, the necessity to choose core contents within the scientific domain, developing a structure map in order to integrate and connect various subject domains, presenting explicitly the objective of inquiry by grades, moving toward integrating science contents, diversifying the construction of science textbooks.

• 한국지구물리탐사학회:학술대회논문집
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• 2008.10a
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• pp.7-11
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• 2008

기상청은 2008년 현재 전국에 107개의 디지털 지진관측망을 운영하고 있다. 또한 지진관측 유관기관인 한국지질자원연구원, 한국원자력안전기술원, 한전전력연구원에서 각 기관의 목적에 맞게 지진관측소를 운영하고 있으며, 이들 지진관측자료의 공유를 목적으로 실시간으로 통합하는 통합지진과측망(KISS)을 2000년에 구축하여 지진분석에 쓰이고 있다. 한반도의 지진발생 현황은 1978년부터 2007년까지 776회로 약 26회/년 정도가 발생하였다. 최근 중국의 쓰촨성과 일본 이와테 지진으로 지진 및 지진예지에 대한 국민적 관심이 대두되고 있다. 한반도에서도 큰 규모의 지진이 발생할 가능성에 대비해 기상청에서는 지진관측망과 지진예지 목적의 지구물리관측망을 구축 중에 있다. 지구물리관측망은 INTERMAGNET에서 등록할 수 있는 수준의 관측소를 목표로 인위적인 자기장의 교란이 적은 지질학적인 요소들을 고려한 후보지 선정을 위하여 지구자기업무에 관한 기획연구(서만철 2007)를 수행 하였다. 그 결과 국가 중심 지구자기관측소의 위치는 충남 공주시와 청양군 사이에 있는 칠갑산 지역이 가장 좋은 후보지라고 제안하여 청양지역을 주변으로 국유림 및 군유지를 조사하여 충남 청양군 장평면 화산리 산 36-2번지에 후보지를 선정하여 최적의 입지 조건을 검증하기 위해 인천교육대학교의 이휘순 교수 MT탐사를 수행 주변의 배경잡음을 측정하여 양호한 조건을 갖춘 것으로 확인되었다. 지구자기관측소에는 Fluxgate Magnetometer 1대, Total field Magnetometer 1대, Theodolite 1대, SP(Self Potential) Monitoring system 1대와 장비들을 보호 할 수 있는 관측소가 설치될 예정이다

• Proceedings of the Korea Water Resources Association Conference
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• 2023.05a
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• pp.269-269
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• 2023

기후 변화로 인한 강우 패턴의 변화는 도심지 방재성능 목표를 상회하는 홍수로 이어져 침수피해를 가중시키고 있다. 이로 인한 도시침수 피해를 저감하기 위하여 도시침수 예측모형 개발이 활발히 이루어지고 있으나, 대규모 관망으로 이루어진 복잡한 도심지 우수관망을 모의하기 때문에 분석속도가 느려 실시간 예측 적용에 한계점이 있다. 도시침수 분석에 가장 많이 활용되는 대표적인 모형인 SWMM(Storm Water Management Model)은 복잡한 관망을 비교적 빠르고 정확히 해석할 수 있어 유용하지만, 이 또한 대도심의 우수관망 모의 시 많은 시간이 소요되며, 관망 정밀도 기준이 정의되어 있지 않아 분석에 어려움이 있다. 이러한 문제점을 해결하기 위하여 본 연구에서는 관망 간소화 기법(유역면적의 밀도, 관거 직경, 관로의 길이 등)을 적용하고, 이에 따른 주요 지선과 간선의 수위 변화와 침수흔적도를 비교하여 분석결과의 정확성을 담보하는 관망 간소화 수준을 파악하고 도시침수 분석 시 적정 간소화 기준과 자동 간소화 방안을 제시하고자 한다. 도시침수 분석 시 우수관망 자동 간소화를 위하여 Python을 활용한 코드를 작성하였으며, SWMM의 .inp 파일을 읽어들여 Dataframe형태로 저장한 후 분석을 위한 데이터 가공, 간소화 기준에 따른 분류, 간소화 대상 수리·수문인자 연산, 인접 간선에 연결, 간소화된 .inp파일 저장의 총 6단계로 구성하였다. 연구 대상지역은 도림천 유역으로 설정하였으며, 초기자료는 맨홀 30,469, 관거 32,443, 소유역 30,586개로 이루어져 있으며, 모의 시간은 약 2시간 30분이 소요되었다. 유역면적 100x100 미만을 대상으로 수행 시 맨홀 9,965, 관거 10,464, 소유역 9,240개로 관거의 복잡도가 약 1/3 감소하였으며, 모의 시간은 약 43분으로 기존대비 약 72% 단축되는 것으로 나타났다. 실제 침수가 발생한 주요지점들을 비교한 결과 R² 0.85 ~ 0.92로 예측모형의 정확도에 큰 영향을 끼치지 않는 것으로 나타났다. 도시침수모형 최적 간소화를 통해 모형의 복잡성을 줄이고, 계산량을 줄여 모형의 수행시간을 단축시킬 수 있으며, 불필요한 우수관망을 제거하거나 병합함으로써, 모형의 예측력 향상과 분석과 해석에 효율적으로 사용될 수 있을 것으로 기대한다.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.34 no.4
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• pp.763-780
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• 2024

As the domestic and international landscape undergoes rapid changes, the importance of implementing security measures in response to the growing threats that businesses face is increasing. In this context, the need for Security by Design (SbD), integrating security from the early design stages, is becoming more pronounced, with threat modeling recognized as a fundamental tool of SbD. Particularly, to save costs and time by detecting and resolving security issues early, the application of the Shift Left strategy requires the involvement of personnel with limited security expertise, such as software developers, in threat modeling. Although various automated threat modeling tools have been released, their lack of user-friendliness for personnel lacking security expertise poses challenges in conducting threat modeling effectively. To address this, we conducted an analysis of research related to threat modeling tools and derived usability evaluation criteria based on the GQM(Goal-Question-Metric) approach. An expert survey was conducted to validate both the validity and objectivity of the derived criteria. We performed usability evaluations of three threat modeling tools (MS TMT, SPARTA, PyTM), and the evaluation results led to the conclusion that MS TMT exhibited superior usability compared to other tools. This study aims to contribute to the creation of an environment where personnel with limited security expertise can effectively conduct threat modeling by proposing usability evaluation criteria.

• Journal of the Korean Geotechnical Society
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• v.34 no.12
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• pp.105-113
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• 2018

In this study, the engineering properties including bearing capacity of subgrades stabilized with a binder are analyzed by laboratory and field experiments. The main components of the binder are CaO and $SO_3$. After the binder was mixed with a low plasticity clay, the passing rates were relatively decreased as the sieve mesh size increased. Not only did the soil type change to silty sand, but engineering properties, such as the plasticity index and modified California bearing ratio (CBR), were improved for the subgrade. A comparison of the compaction curves of the stabilized subgrade and field soil compacted with the same energy demonstrated an increase of approximately 6% in the maximum dry unit weight, slight decrease in optimum moisture content, and considerable increase improvement in grain size. In the modified CBR test, the effect of unit weight and strength increase of the modified soil (with a specific amount of binder) was remarkably improved. As the proportion of granulated material increased after the addition of binder, the swelling was reduced by 3.3 times or more during initial compaction and 6.5 times by final compaction. The unconfined compressive strength of the specimens was maintained at the homogeneous value with a constant design strength. The stabilized subgrade was validated by applying it in the field under the same conditions; this test demonstrated that the bearing capacity coefficients at all six sites after one day of compaction exceeded the target value and exhibited good variability.

• Journal of the Korea institute for structural maintenance and inspection
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• v.24 no.3
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• pp.47-56
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• 2020

In this study, three levels of W/B(Water to Binder) ratio (0.37, 0.42, 0.47) and substitution ratio of GGBFS (Ground Granulated Blast Furnace Slag) rate (0 %, 30 %, 50 %) were considered to perform RCPT (Rapid Chloride Diffusion Test) at the 1,095 aged day. Accelerated chloride diffusion coefficient and passed charge of each concrete mixture were assessed according to Tang's method and ASTM C 1202, and improving behaviors of durability performance with increasing aged days are analyzed based on the test results of previous aged days from the preceding study. As the age of concrete increases, the passed charge and diffusion coefficient have been significantly reduced, and especially the concrete specimens containing GGBFS showed a significantly more reduction than OPC(Ordinary Portland Cement) concrete specimen by latent hydraulic activity. In the case of OPC concrete's results of passed charge, at the 1,095 days, two of them were still in the "Moderate" class. So, if only OPC is used as the binder of concrete, the resistance performance for chloride attack is weak. In this study, the time-parameters (m) were derived based on the results of the accelerated chloride diffusion coefficient, and the deterministic and probabilistic analysis for service life were performed by assuming the design variable as a probability function. For probabilistic service life analysis, durability failure probabilities were calculated using Monte Carlo Simulation (MCS) to evaluate service life. The service life of probabilistic method were lower than that of deterministic method, since the target value of PDF (Probability of Durability Failure) was set very low at 10 %. If the target value of PDF suitable for the purpose of using structure can be set and proper variability can be considered for each design variable, it is believed that more economical durability design can be made.

• Journal of the Institute of Electronics Engineers of Korea SC
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• v.45 no.6
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• pp.48-54
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• 2008

Biochemical weapons, called as a poor nation's nuclear-weapon, are most favorable Weapons of Mass Destruction(WMD). At the beginning of war, these biochemical weapons, which can threaten the operations of our forces and cause the anxiety and chaos of people, should be used to attack our principle facilities. And these attacks might be conducted as a long term scenario over the war. Consequentially, our military training as well as civilian-military joint training have been focused on these circumstances to improve defense capability against the invasion of biochemical weapons. Add to these efforts, there have been a lot of researches to develop advanced decontaminations that can secure our troops and equipments. In this study, applicability of the water-soluble decontaminant for the contaminated aircraft was evaluated. The water-soluble decontaminant has been applied to the military stations and ground weapon systems only. According to the theoretical analyses and published papers, the water-soluble decontaminant has been shown better decontamination capability than commercial cleaner by roughly 50%. Furthermore, as a result of experiment efforts in this study, it was showed that the water-soluble decontaminant can reduce corrosion risk which is primary concern for the aircraft structures.