• Journal of the Korea Institute of Military Science and Technology
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• v.2 no.1
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• pp.150-158
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• 1999

A driving system of a dynamic FOG compass with a stabilized platform is described. A stepping motor adopted as a driving motor is required to maintain a stable operation with constant speed and low oscillation for the proper operation of the FOG compass itself. The previous stabilization scheme operated on frequency-modulated supply is modified to include fuzzy control algorithm. The proposed scheme has advantages, particularly in the size, weight and flexibility of the driving system.

• Proceedings of the KIEE Conference
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• 2006.11a
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• pp.390-392
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• 2006

대규모 전력계통인 한국전력과 154kV 송전선로로 연계되는 석유화학공장 전력계통에 작은 용량의 자가발전기가 병렬운전 되는 경우이다. 전기사고로 한국 전력과의 연계 송전선로가 개방되어 석유화학공장 전력계통이 단독으로 분리되면 발전이 수요에 크게 못 미치게 되어 급격한 주파수 저하 및 과도한 전압강하가 나타나고 이로 인하여 발전기가 정지되어 공장 전체가 정전에 이르게 되는 사고 가능성이 있다. 본 논문은 이와 같은 대규모 전력계통과의 연계선로 개방으로 나타나는 과부하 상태에서 주파수 안정화 및 전압강하에 대처할 수 있는 부하차단 또는 계통 분리로 수급 불균형을 해소하고, 단시간 전압강하 상태에서도 효과적으로 전력계통 안정화가 지속될 수 있는 방안 등을 전력계통 동특성 해석도구를 이용하여 모의하고 이를 실제 전력계통에 적용코자하는 사례 연구이다.

• Journal of Teachers' Pension
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• v.4
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• pp.57-90
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• 2019

본 연구는 사학연금의 장기적 재정건전성을 확보하기 위한 재정추계 및 정책평가 방법에 관하여 논의한다. 먼저 재정안정화 시나리오의 설정에 있어서 기간간 예산제약식을 이용하여 장기적으로 균제상태(steady state)를 달성할 수 있는 납부율 및 급여율의 선정이 어떻게 이루어질 수 있는지 살펴본다. 또한 재정추계에 있어서 정책 변화에 따라 개인들의 행동 패턴이 달라질 가능성이 있음을 강조하고, 조기퇴직 결정에 관한 캘리브레이션을 통해 재정추계에서 내생성에 대한 고려가 어떻게 이루어질 수 있는지 예시한다. 마지막으로 힉스 보상의 개념에 기초하여 안정화 정책에 대한 평가가 연금 재정지표에 미치는 효과만이 아니라 가입자 / 수급자의 후생에 미치는 영향까지 같이 고려하여 이루어질 필요가 있음을 설명한다.

• Economic and Environmental Geology
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• v.54 no.1
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• pp.21-33
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• 2021

The purpose of this study is to determine the order of priority for the use of amendments, matching the optimal amendment to the specific site in Korea. This decision-making process must prioritize the stabilization and economic efficiency of amendment for heavy metals and metalloid based on domestic site contamination scenarios. For this study, total 5 domestic heavy metal contaminated sites were selected based on different pollution scenarios and 13 amendments, which were previously studied as the soil stabilizer. Batch extraction experiments were performed to quantify the stabilization efficiency for 8 heavy metals (including As and Hg) for 5 soil samples, representing 5 different pollution scenarios. For each amendment, the analyses using XRD and XRF to identify their properties, the toxicity characteristics leaching procedure (TCLP) test, and the synthetic precipitation leaching procedure (SPLP) test were also conducted to evaluate the leaching safety in applied site. From results of batch experiments, the amendments showing > 20% extraction lowering efficiency for each heavy metal (metalloid) was selected and the top 5 ranked amendments were determined at different amount of amendment and on different extraction time conditions. For each amendment, the total number of times ranked in the top 5 was counted, prioritizing the feasible amendment for specific domestic contaminated sites in Korea. Mine drainage treatment sludge, iron oxide, calcium oxide, calcium hydroxide, calcite, iron sulfide, biochar showed high extraction decreasing efficiency for heavy metals in descending order. When the economic efficiency for these amendments was analyzed, mine drainage treatment sludge, limestone, steel making slag, calcium oxide, calcium hydroxide were determined as the priority amendment for the Korean field application in descending order.

• Journal of the Korea Organic Resources Recycling Association
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• v.23 no.4
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• pp.40-51
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• 2015

This study is to estimate the viability of aerobic stabilization technology for reducing greenhouse gas (GHG) emissions from landfills in Korea. In this study, methane emissions were estimated by applying Landfill gas estimation model (LandGEM) to Y landfill in Korea. By comparison of an anaerobic condition (baseline) and an aerobic condition, the amount of $CO_2eq$ savings was calculated. The $CO_2eq$ savings take place inside the landfilled waste during aeration due to the conversion of previously anaerobic biodegradation to aerobic processes, releasing mainly $CO_2$. It was demonstrated that 86.6% of the total GHG emissions occurring under anaerobic conditions could be reduced by aerobic stabilization technology. This means the aerobic stabilization technology could reduce environmental contamination through early stabilization and GHG emissions considerably at the same time. Therefore, the aerobic stabilization technology is one of the optimal technologies that could be employed to domestic landfill sites to achieve sustainable landfill.

• Journal of Navigation and Port Research
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• v.36 no.5
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• pp.379-385
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• 2012

In this paper, the stability and stabilization problems for marine vessels including surface and underwater vehicles are described. In the marine vessels, there are many and strong nonlinear parameters. These give hard design process and difficulties to us. In this article, at first we make a descriptor system representation as a controlled system to preserve the physical parameters of the system as it is. And we propose a new stability and stabilizability conditions based on the quadratic stabilization approach which gives a solution for the unreasonable problems produced by added mass. That is, the proposed conditions are not interfered with the nonsymmetric matrix constraint. And the stability condition is given by an matrix inequality such that it makes us to obtain a solution easily for something.

• The Microorganisms and Industry
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• v.18 no.3
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• pp.10-22
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• 1992

퇴비화는 유기물이 생물의 작용에 의해 분해되면서 보다 안정화된 형태로 변형되어 가는 과정으로 여러가지 환경요인에 의해 영향을 받는다. 본 논문에서는 유기물의 퇴비화 과정에 영향을 주는 요인을 토양 생화학적 및 미생물학적 측면으로 분석하여 퇴비화 공정설계에 있어 분해원리의 이해에 도움을 주고자 하며, 퇴비화 후 최종적인 사용, 즉 농업적 이용 가능성에 대해서도 간략하게 기술하고자 한다.

• Economic and Environmental Geology
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• v.52 no.1
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• pp.29-35
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• 2019

The purpose of this study was to assess the applicability of acid mine drainage sludge (AMDS) pellets for the arsenic (As) stabilization and to suggest an evaluation method for arsenic stabilization efficiency in soil around abandoned coal mines. The soil samples were collected from the agricultural field around Ham-Tae, Dong-Won, Dong-Hae, and Ok-Dong coal mine. The As concentration in soil was exceeding the criteria of soil pollution level, except for Ham-Tae coal mine. The AMDS pellets are more appropriate to use by reducing dust occurrence during the transport and application process than AMDS powder. In addition, AMDS pellets were maintained the As stabilization efficiency. The application of AMDS pellets for the As stabilization in soil was assessed by column experiments. The AMDS pellets were more effective than limestone and steel slag, which used as the conventional additives for the stabilization process. The As extraction by $0.43M\;HNO_3$ or $1M\;NaH_2PO_4$ solution were appropriate evaluation methods for evaluation of As stabilization efficiency in the soil.

• The Journal of the Korea Contents Association
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• v.21 no.4
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• pp.96-110
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• 2021

Korea is faced with the challenge of adapting to the world's fastest - growing low birthrate, aging society, and low growth with low interest rate era. With low fertility and aging population, the factors of financial income of health insurance are decreasing, and the increase of public interest in health, high cost medical technology and the development of medicine are leading to increase expenditure of health insurance. In this study, I will examine the strengthen protection of health insurance, financial stabilization, and fairness of medical care. First, the present status and limitations of health insurance were identified through domestic policy report, domestic and foreign literature, and precedent research. Second, the foreign health insurance policy measures to stabilize the finances were examined separately. Based on this study, in order to maintain sustainable health insurance through reinforcement and financial stabilization of health insurance, the current financial income structure of health insurance must be renovated. It will be necessary to expand government subsidies and discover new tax revenues. In addition, a policy to save finances by reorganizing the medical bill payment system and medical delivery system will also be needed.

• Journal of the Society of Cosmetic Scientists of Korea
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• v.36 no.1
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• pp.1-16
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• 2010

The preparation and properties of emulsions stabilized by the adsorption of solid particles at the oil-water interface are reviewed. Comparison is made with the behaviour of surfactant-stabilized emulsions. Many of the properties of Pickering emulsions are attributed to the large free energy of adsorption for particles. The main differences is due to the irreversible adsorption of particles to the interface. Phase inversion from w/o (water-in-oil) to o/w (oil-in-water) can be brought by increasing the volume fraction of water. Hydrophilic particles tend to form o/w emulsion whereas hydrophobic particles form w/o emulsion. The contact angle at the oil-water interface is main parameter to decide the emulsion type. The aspects of stability of Pickering emulsions are in contrast to general emulsions in some points. The possibility using Pickering emulsions for cosmetics is also proposed.