• IEMEK Journal of Embedded Systems and Applications
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• v.11 no.5
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• pp.305-312
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• 2016

Modern embedded systems are typically operated by the rechargeable batteries in our daily life. Since charge of batteries is considered as an time consuming task, there have been extensive efforts to manage the charge time from the perspective of materials, circuits, and systems. Estimation of battery charge time is one of the essential information to design the charge circuitry. A compact macro model for the constant-current and constant-voltage charge protocol was recently introduced, which gives us a quick estimation of charge time with similar shape to the famous Peukert's law for discharge time estimation. The CC-CV charging protocol is widely used for Lithium-based batteries and Lead-acid batteries. In this paper, we characterize the lead-acid battery by measurement to extract the model coefficients, which was not covered by the previous studies. By our proposed model, the key coefficient Kcc results in 1.18-1.31, which is little bit higher than that of Lithium batteries. The accuracy of our model is within the range of ${\pm}10%$ error, which is compatible with the other studies such as Peukert's law.

• 한국태양에너지학회:학술대회논문집
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• 2012.03a
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• pp.200-205
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• 2012

In the high oil price age, intensification of energy efficiency promotion in the building sector is required. Windows are dominating in large percent of whole building loads, and are regarding as the primary target of energy efficiency. In this study, in order to reduce heat loss of buildings, we investigate the thermal performance properties of Temperable Low-e glazing coated Ag membrane that has high electrical conductivity. The Temperable Low-e glazing windows has high insulation and shading properties, and it has strength that can supply various product which consumers want. In order to evaluate thermal performance of temperable windows, we install single low-e windows and double low-e windows in the experimental chamber and analysis the comparison heating energy consumption between single and double Low-e glazing windows. performance evaluation was conducted.

• Journal of Powder Materials
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• v.14 no.5
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• pp.309-314
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• 2007

Zirconia powders with nano size pores and high specific surface areas were synthesized via aqueous precipitation and hydrothermal synthetic method using $ZrOCl_28H_2O$ and $NH_4OH$ under pH=11 and ambient condition. By this reaction. zirconia hydrate $(ZrO_x(OH)_{4-2x})$ was primarily synthesized and the obtained zirconia hydrate was heat treated hydrothermally using an autoclave at various temperatures under pH=11. X-ray diffraction, Scanning electron microscopy, Energy dispersive X-ray spectroscopy, FT-IR, Raman, Particle size analysis, DTA-TG, and BET techniques were used for the characterization of the powder. The synthesized zirconia showed an amorphous phase, however, the phase was transformed to the crystalline state during the hydrothermal process. The observed crystalline phase above $160^{\circ}C$ was a mixed phase of monoclinic and tetragonal zirconia. By the BET analysis, it was found that the specific surface area was ranged in $126{\sim}276m^2/g$ and the zirconia had the cylindrical shaped pores with average diameter of $2{\sim}7nm$.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.37A no.10
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• pp.858-864
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• 2012

In South Korea, to effective and systematic response to disasters, the government will build wireless communication network for PPDR(Public Protection and Disaster Relief) on a national level by 2015. To do it, as MOPAS(Ministry of Public Administration and Security) requested the new frequency assignment for PPDR, KCC(Korea Communications Commission) has been examined new frequency allocations about TETRA and WiBro technologies. In this paper, we were defined the technical parameters, were estimated the spectrum of TETRA-TRS requirements for Korean wireless communication of PPDR based on M.2033 methodology recommended by ITU-R.

• Journal of Satellite, Information and Communications
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• v.5 no.2
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• pp.75-81
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• 2010

COMS (Communication, Ocean and Meteorological Satellite) is the multi-purposed Korean geostationary satellite funded by four Korean government ministries, and is to supply communication services, ocean and weather observation for 7 years. As part of COMS, development of Ka band communication payload composed of microwave switching transponder and multi-horn antenna is sponsored by KCC (Korea Communications Commission) and developed by ETRI (Electronics and Telecommunications Research Institute). The purpose of Ka Payload development is to acquire space proven technology of Ka payload and to exploit advanced multimedia communication services. This paper aims to study development technology of Ka payload system through whole process of ETRI project. Also application of Ka payload will be dealt in this paper.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.47 no.12
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• pp.104-110
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• 2010

Japan TV broadcasting signals are measured and analyzed to estimate spillover level from Japan during 44 months from Feb. 2003 to Oct. 2009. Electric field intensity spillover into Korea is measured using fixed measurement system in Busan, and the relationship between the measured data and the predicted value is analyzed by year and seasons. Measurement results show that spillover signals from Japan have a serious effect on Korea broadcasting environment, and so that proper digital switchover strategy is necessary to cope with the spillover situation.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.47 no.12
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• pp.97-103
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• 2010

In this paper, worldwide standards and regulations on in-band/out-of-band emission characteristics of DTV broadcasting equipments are reviewed, and emission mask requirements of several equipment types are analyzed. Out-of-band emission mask draft suitable for DTV repeater is proposed and its usefulness is evaluated and verified in the experiments. Using the proposed standard, small-sized and cost effective DTV repeater can be implemented to broaden DTV broadcasting coverage for digital switchover.

• Journal of the Semiconductor & Display Technology
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• v.12 no.3
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• pp.47-51
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• 2013

Current research trends of solar cells has focused on the high conversion efficiency and low-cost production technology. Passivation technology that can be easily adapted to mass production. Therefore, this study conducted experiments with aim of the following two methods for the fabrication of high-efficiency crystalline silicon solar cells. In the first task, an attempt is formation of local Al-BSF to a number of locally doped dots to increase the conversion efficiency of solar cells to reduce the loss of $V_{oc}$ overcome. The second major task, rear surface apply in $Al_2O_3/SiN_x$ stack layer, $Al_2O_3$ prominent negative fixed charge characteristics. As the result of task, Local Al-BSF and $Al_2O_3/SiN_x$ stack layer applied to the p-type single crystalline silicon solar cells, the average $V_{oc}$ of 644mV, $I_{sc}$ of 918mV and conversion efficiency of 18.70% were obtained.

• Journal of the Korean GEO-environmental Society
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• v.22 no.8
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• pp.13-19
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• 2021

In the case of construction on soft ground - such as national expressways sponsored by Social Overhead Capital (SOC) - many problems occur due to excessive settlement: therefore, an accurate settlement prediction has a major impact on the selection of improvement methods, project budget and construction period. Most of the settlement prediction methods currently used in projects apply Terzaghi's Theory of One-Dimensional Consolidation which assumes the uniformity of the depth of the soft ground. However, the results of soft ground settlement predictions vary when the target layer is divided into multiple horizontal layers. This study analyzed the change in the consolidation settlement behavior according to the horizontal division of soft ground as well as with different loading height.

• Proceedings of the Korean Society of Disaster Information Conference
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• 2022.10a
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• pp.335-336
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• 2022

연구목적: 감염병 유행시 감염병 의심 환자의 구급활동을 위해 출동한 소방대원의 안전을 확보하고, 현장에서 수집된 정보를 바탕으로 지역별 감염병 의심환자 발생 현황을 파악하여 현장 통제 및 지원이 가능한 소방 감염병 관리 시스템을 개발하고자 한다. 연구방법: 감염병 의심 환자를 분류할 수 있는 스마트폰 앱을 개발하여 감염병 의심 여부를 확인하고, 감염병 의심 환자로부터 감염을 방지하기 위해 환자 식별용 NFC태그를 1회용 형태로 개발한다. 현장에서 입력되는 감염병 의심 응급환자 관련 데이터를 수집하고 분석할 수 있는 관리 시스템을 개발하여 해당 업무 관련자에게 제공하여 감염병 의심 응급환자의 이송을 개선하는지 평가한다. 연구결과: 실험결과 스마트폰 앱에 구현된 알고리듬을 통해 감염병 의심 여부를 판단할 수 있었으며, 적정 이송병원으로 이송함으로써 재이송 비율히 현저히 감소되었다. 결론: 본 연구를 통해 응급의료 서비스에 ICT 기술을 적용하여 응급의료 서비스를 개선할 수 있는 가능성을 확인하였으며 특히 감염병 의심환자에 대한 적정병원 이송으로 이송시간 단축 및 응급환자의 소생률 향상과 함께 구급대원의 안전을 적극적으로 확보할 수 있을 것으로 기대된다.