• Journal of Electrical Engineering and Technology
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• v.13 no.3
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• pp.1232-1240
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• 2018

This paper aims at designing an intelligent controller, based on control Lyapunov Function strategy integrated with fabricating discrete model of Buck and Boost converters and analyzing energy changes during the DC/DC progress to realize tracing reference current on Buck and Boost converters. In addition, practical stability phenomenon research and transient performance analysis has been proposed to give an insight to the influence of controller parameters in achieving an enhanced output performance and how the time of sample period affect the error of practical stability will be illustrated. The novelty of this controller in comparison to other schemes lies in the improved performance of practical stability.

• Proceedings of the KIPE Conference
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• 2012.07a
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• pp.271-272
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• 2012

전류 적산법(Coulomb counting, ampere counting)을 이용한 배터리 SOC(State-of-Charge) 추정 방법은 상용화된 IC를 사용할 수 있기에 구현이 간단하고 SOC 정의를 통해 배터리 사용 가능한 시간을 쉽게 예측할 수도 있다. 하지만 초기 SOC 오류와 누적되는 전류 정보의 오차로 인해 추정이 실패하는 단점이 존재하기 때문에 이를 해결해주는 알고리즘이 필요하다. 본 논문에서는 전류 적산법 기반의 배터리 SOC 추정 회로에 확장 칼만 필터(EKF, Extended Kalman Filter)를 접목하여 전류 적산법을 이용하였을 때 나타날 수 있는 오차 누적을 줄이는 알고리즘을 제안한다. 또한 실험을 통해 제안된 배터리 SOC 추정 회로의 성능을 확인해본다.

• Proceedings of the KIPE Conference
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• 2016.11a
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• pp.75-76
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• 2016

The relationship of widely used Open circuit Voltage (OCV) versus State of Charge (SOC) is critical for any reliable SOC estimation technique. However, the hysteresis existing in all type of battery which has been come to the market leads this relationship to a complicated one, especially in Lithium Iron Phosphate (LiFePO4) battery. An accurate model for hysteresis phenomenon is essential for a reliable SOC identification. This paper aims to investigate and propose a method for hysteresis modeling. The SOC estimation is done by using Extended Kalman Filter (EKF), the parameter of the battery is modeled by Auto Regressive Exogenous (ARX) and estimated by using Recursive Least Square (RLS) filter to tract each element of the parameter of the model.

• Proceedings of the KIPE Conference
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• 2018.11a
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• pp.45-47
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• 2018

본 논문은 High Altitude Electromagnetic Pulse (HEMP) 응용 분야에 적용되는 리튬 이온 베터리를 이용한 커패시터 충전전원 장치에 관하여 다룬다. 기존에 제안하였던 5.4 kJ/s 고전압 커패시터 충전기를 9 kJ/s 로 용량을 늘렸고, 고전압 커패시터 충전기 후단에 공진 충전 회로를 도입하여 2단 충전 구조로 펄스 방전 시 발생할 수 있는 역전압과 reflecting pulses로 부터 커패시터 충전 전원 장치를 보호한다. 제안하는 충전기의 성능은 시뮬레이션 및 기초 부하 실험을 통해 확인되었다.

• Electronics and Telecommunications Trends
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• v.37 no.1
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• pp.10-20
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• 2022

A drone without attaching guns or bombs can be a dangerous weapon, since its motor speed is greater than 3000 rpm, which is similar to that of a mower powered by a LiPo battery. The anti-drone system is the only means of detecting and neutralizing drone attacks. Many defense companies around the world provide solutions using various types of equipment (for example, radar, cameras, jamming guns, and net guns). ETRI has also developed a Low-Altitude Drone Detection (LADD) system consisting of Ku-band radar and an Electro-Optical/Infra-Red (EO/IR) camera. In this paper, we summarize recent technical advances in anti-drone systems around the world and introduce the features and describe the performance of the LADD system.

• International conference on construction engineering and project management
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• 2009.05a
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• pp.558-565
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• 2009

In recent years, the demand for green buildings is growing fast due to legislative and social pressures. Construction organizations, which play an important role in promoting building industry growth, are facing with challenges on how to adapt themselves to enhance sustainability of the buildings. In this paper, the green value chain and system frameworks, an extend application of Porter's value chain and system models, are introduced. Based on deep analysis of the green value chain and system frameworks, a revolution model for construction organizations towards green building is created. Management factors critical for a successful green building project, at the firm and project organization level, are extracted. Furthermore, external critical relationships are also identified. Fully understanding of these management factors and the model can help and enable practitioner to know what new capabilities should be deployed and developed in the long run for maximizing sustainability.

• Proceedings of the Korean Society of Disaster Information Conference
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• 2022.10a
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• pp.369-370
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• 2022

4차 산업혁명이 도래함에 따라서 군사용으로 개발된 드론이 광범위하게 다양한 분야에 활용되어 가고 있다. 드론의 활용으로 이전에 사람이 접근하기 어려웠던 지역이나 현장을 원격탐사 및 데이터 취득이 가능하게 되면서, 도시문제 해결과 재난에 대응할 수 있다. 하지만 기존 드론의 동력원으로 사용하는 리튬폴리머(Li-Po)는 짧은 비행시간 때문에, 재난 현장의 드론 투입에 한계가 있다. 이러한 문제점을 보완하기 위하여 기존 드론 대비 4배 이상 향상된 비행시간을 통해 장기체공이 가능한 액화 수소 드론의 도입이 필요한 것으로 보인다. 늘어난 비행시간과 비가시 장거리 비행 능력을 통해 높은 효율을 낼 수 있는 액화 수소 드론의 활용으로 효과적인 재난 대응 활동에 대한 연구가 필요하다.

• Korean Journal of Soil Science and Fertilizer
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• v.6 no.3
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• pp.193-197
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• 1973

1. Two desert perennial plant species (Lycium andersonii Gray and Atriplex confertifolia (Torr. & Frem) Wats.) were grown in soil in a glasshouse with different sources of Na ($NO_3{^-}$, $Cl^-$, $H_2PO_4{^-}$) to evaluate their effects upon cation-anion balance in the plants. 2. Each anion greatly increased in leaf with only minor, if any, interactions with other anions 3. The miliequivalent sum of anions measured (N. P. Cl), increased in each plant part with the soil applications. 4. Simultaneously there were usually modest increases in the me. sum of cations. 5. The cation-anion ratio was decreased markedly when $NaNO_3$ was added. The ratio was usually over one. 6. Maximum content of Cl and N in leaves with L. andersonii. was 13.5%, and 6.37% respectively, when each was added. 7. Sodium concentrations were higher for the Atriplex species than for L. andersonii. 8. There were some compensations among other cations as sodium was increased, so that a somewhat constant sum of cations was maintained although there were significant differences among different sources of Na. 9. L. andersonii appeared to be an accumulator of Li.

• Polymer(Korea)
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• v.25 no.1
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• pp.6-14
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• 2001

The monomer N,N'-bis(3-pyrrol-1-yl-propyl)-4,4'-bipyridinium$(PF_6)_2$ was electrochemically polymerized on glassy carbon electrode surface. This polymer film electrode has electroactive sites on its bipyridinium ions distributed at the polymer strands. The formal potentials of the electrodes were -0.41V and -0.81V(vs. SSCE) for each step at phosphate buffer(pH=5.70). The diffusion coefficients of the dopants ions into the polymer matrix were $1.57{\times}10^{-4}$ and $4.35{\times}10^{-5}cm^2s^{-1}$ for first and second redox couple, respectively. The rate constants of electron transfer at $V^{2+/+}$ of the first step was a $57.53s^{-1}$, which was 22 times higher than $V^{+/0}$ one having $2.63s^{-1}$ in the solution. The charge transfer resistance of the polymer film was influenced by the dopant ion of the electrolyte. Thus the resistances were 22.63, 16.81, 12.44 and $11.36k{\Omega}$ for $LiClO_4,\;NaClO_4,\;KClO_4$, and phosphate buffer, respectively. The reaction order of the electropolymerization was first order and the rate constant of the polymerization was $1.31{\times}10^{-1}s^{-1}$ as determined by EQCM method. The G.C./p-BPB type electrode doped with phosphate ions showed a stability and reproducibility in CV procedure over 20 cycles.

• Spatial Information Research
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• v.14 no.1 s.36
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• pp.129-150
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• 2006

Mineral potential mapping is an important procedure in mineral resource assessment. The purpose of this study is to analyze mineral potential using weight of evidence model and a Geographic Information System (GIS) environment to identify areas that have not been subjected to the same degree of exploration. For this, a variety of spatial geological data were compiled, evaluated and integrated to produce a map of potential mineral in the Gangreung area, Korea. for this, a spatial database considering mineral deposit, topographic, geologic, geophysical and geochemical data was constructed for the study area using a GIS. The used mineral deposits were non-metallic(Kaolin, Porcelainstone, Silicastone, Mica, Nephrite, Limestone and Pyrophyllite) deposits of sedimentary type. The factors relating to mineral deposits were the geological data such as lithology and fault structure, geochemical data, including the abundance of Al, As, Ba, Ca, Cd, Co, Cr, Cu, Fe, K, Li, Mg, Mn, Mo, Na, Ni, Pb, Si, Sr, V, Zn, $Cl^-,\;F^-,\;{PO_4}^{3-},\;{NO_2}^-,\;{NO_3}^-,\;SO_{42-}$, Eh, PH and conductivity and geophysical data, including the Bouguer and magnetic anomalies. These factors were used with weight of evidence model to analyze mineral potential. Probability models using the weight of evidence were applied to extract the relationship between mineral deposits and related factors, and the ratio were calculated. Then the potential indices were calculated by summation of the likelihood ratio and mineral potential maps were constructed from Geographic Information System (GIS). The mineral potential maps were then verified by comparison with the known mineral deposit areas. The result showed the 85.66% in prediction accuracy.