• Progress in Medical Physics
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• v.8 no.1
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• pp.25-29
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• 1997

Ir-192 source activity for high dose rate brachytherapy is measured using Farmertype ionization chamber. The source-to-chamber distance is 10 cm and the measured charge unit is converted to activity unit. The measured values are compared to the values provided from vendor. Because of time dependency of Ir-192 source activity, the activities are regularly checked and compared to calculated values. As the accuracy of Ir-192 source activity is depend on the mechanical measurement setup, we estimated the precision of remote controlled source dwell position using home-made device and film scanner. The difference between measured and predicted dwell position is within 1 mm. As a result, the errors of source activity are 0.7${\pm}$1.5 ％ for measured and vendor-provided values and 0.l${\pm}$1.2％ for measured and time-dependent calculated vlaues. In conclusion, our measured activity has been comparable to the values provided from vendor and our brachytherapy unit has been very accurate until now. Regular quality control of brachytherapy is essential for successful treatment which depends on the accuracy of source position and activity.

• Clean Technology
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• v.26 no.1
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• pp.13-21
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• 2020

Air pollutants in a subway are complexly caused by outdoor factors such as ventilating opening and indoor factors such as the movement of passengers on the subway. According to recent research results, most of the air pollutants generated in subway tunnels and stations are caused by indoor variables such as train movement. To control air pollutants such as particulate matter (PM), a prevention facility such as the electrostatic precipitator (EP) or bag filter collector was required in a subway station. In particular, the PM removed by the EP must be kept clean continuously to manage PM effectively. Therefore, a nano-bubbling washing system was developed in this study to clean a contaminated collecting plate in an EP at the main subway tunnel in Seoul. Removal efficiency compared with normal water and nano-bubbling water was likewise studied. As a result, the washing efficiency of collective PM increased in accordance with the increasing of injection pressure, with nano bubbling washing being 130.8% higher than tap water. According to increase in washing times, the maximum washing efficiency was 143.1% higher than tap water, but suitable washing times were less than 3 times. According to the results of the washing efficiency by variation of residence time, it was confirmed that the maximum residence time of nano-bubble water was maintained within 5 minutes.

• Proceedings of KOSOMES biannual meeting
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• 2007.05a
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• pp.21-26
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• 2007

The Protocol adopted in Sep. 1997 included the new Annex VI of MARPOL 73/78, which entered into force on 19 May 2005. Revision for the accept MARPOL Annex VI with make public on 29 Dec. 2005 and enforce on 29 Jun. 2006. For all that not installation at oil terminal or if installed do not used. The purpose of this study is to research and evaluate the methods of sampling and analysis, and the pollution measure of existed VOCs during the bulk liquid cargo operation at vessels. As the sampling instrument of VOCs, Tedlar bag has the effect of decrease in concentration by the chemical reaction and absorption, and the method using the solvent extraction has error cause because of the extraction, the absorption tube has error by the breakthrough. But canister is the best sampling instrument because of having no sampling mistake. The study on VOCs emission is not sufficient for the research on the pollution cause and the analysis data on the HAP during the bulk liquid cargo operation at vessels. Hence, monitoring on the management hazardous VOCs need to be continued during the cargo operation at vessels and VOCs management field must be study for the make progress at a good pace for reason of crew's health.

• Journal of the Korean Society of Food Science and Nutrition
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• v.44 no.6
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• pp.904-911
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• 2015

The objective of this study was to investigate the quality characteristics of traditional wine using an radio-frequency identification (RFID) system annexed to a fermenter. In this study, we proposed an RFID-based data transmission scheme for monitoring fermentation of traditional alcoholic beverages. The pH, total acidity, total sugar, soluble sugar, free sugar, alcohol content, and organic acids of were investigated and subjected to fermentation of traditional alcoholic beverages three times. The pH ranged from 7.98, 7.95, and 7.68 at day 0, decreased drastically to 3.31~2.96 at day 2, and then slowly increased to the end point, finally reaching 3.34 at day 20. Acidity tended to increase quickly with time, especially for all samples after day 2. The fermentation environment induced a sudden increase acidity in reactants and indicated a low pH. The total sugars during fermentation quickly decreased to the range of 20.3, 22.43, and 19.2% at day 2, and the slope of reduction steadily decreased to 5.1, 6.1, and 4.8% at day 10. On the other hand, the alcohol content showed the reverse trend as total sugars. The alcohol content also showed the same pattern as total acids, showing the highest alcohol content of 17.3% (v/v) on day 20. In this study on traditional wine fermentation using an RFID system, we showed that pH, soluble sugar, and alcohol content can be adopted as key indicators for quality control and standardization of traditional wine manufacturing.

• Korean Journal of Environmental Agriculture
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• v.21 no.4
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• pp.243-247
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• 2002

Irrigation water quality along Donjin river watershed was monitored to find a possible pollutant, for maintaining water quality to achieve food safety through water quality preservation of river. As a pollution indicators, such as Biological Oxygen Demand(BOD), Chemical Oxygen Demand(COD), Total Nitrogen(T-N), and Total Phosphate(T-P) in Dongjin river were examined from May to November in 2001. The results were as follows : The BOD level of Dongjin river ranged from 2.84 to 6.45 mg/L, which would be in a II$\sim$IV grade of the potable water criteria by Ministry of Environment. Averaged BOD level of downstream DJ6(After Jeongupcheon confluence) was 4.07 mg/L. The average COD level of Dongjin river ranged from 11.20 to 32.96 mg/L. COD level of DJ6 rapidly increased rapidly after the junction of Dongjin river and Jungupcheon because it showed the latter had relatively high pollution level. T-N content were significantly high in all sites of Dongjin river ranged through 4.16 to 5.84 mg/L. T-P examined high concentration than another thing point by 0.19 mg/L after Jeongupcheon confluence as BOD and COD. COD of main stream was expressed high concentration to dry season after rainy season. In case of T-P, pollution degree of dry season before rainy season appeared and examined that quality of water was worsened go by dry season after rainy season. The water quality of Dongjin river was deteriorated with inflow of Jungupcheon polluted by municipal and industrial sites near Jungup city.

• Proceedings of the Korea Water Resources Association Conference
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• 2006.05a
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• pp.457-461
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• 2006

비점원 농촌유역으로부터 강우시 영양물질(질소, 인)의 유출특성을 파악하기 위해 2002년부터 2005년까지 5개의 강우사상을 대상으로 $2{\sim}12$시간 간격으로 유량 및 수질을 측정하였다. 강우사상시 TN농도는 유량이 증가함에 따라 상승하여 최대농도를 보인 후, 유량감소에 따라 농도가 감소하는 경우와 초기농도보다 높은 농도로 유지되는 경우의 두 가지 경향을 보였다. TP농도는 유량의 증가에 따라 급격한 상승을 보였고, 최대 값 이후 농도가 낮아져 거의 초기농도에 도달하였다. 또한, 초기농도에 대한 최대농도값의 비는 TP가 TN보다 크게 나타났다. 농촌 소유역에서의 초기유출현상(first-flush)은 40%의 누적유출량을 나타낼 때 TP의 누적유출부하량은 $70{\sim}86%$를 기록하여, 도시유역(60%)과 광역논(50%)보다 크게 나타났는데, 이는 농촌 소유역이 경사가 크고 밭 등에서 강우로 인한 토양침식 등의 영향을 크게 받기 때문으로 사료된다. 4개의 강우사상에 대한 질소의 용존성 성분의 비(TN/TDN비)는 93.6%를 나타내 질소는 대부분 용존성 형태로 유출되는 것으로 나타났고, 인의 용존성 성분의 비(TP/TDP비)는 25.4%를 나타내 인의 대부분 입자성 형태로 유출되는 것으로 나타났다. 따라서, 비점원 농촌유역으로부터 TN부하를 저감시키기 위해서는 용존성 성분을 제공하는 비료의 시용량을 줄여야 하며, TP부하를 저감시키기 위해서는 강우시 입자성 인의 유출을 제어해야 한다. 이를 위해서는 비가 많이 오는 여름철에 나지(裸地)나 밭에 식생이나 멀칭(mulching) 등으로 토양침식을 방지하는 대책이나 하천변에 완충역(riparian buffer zone)을 설치하는 대책이 필요하다. 저수지 관리를 효과적으로 수행하기 위해서는 저수지 내부의 탁도 거동을 정확히 예측할 수 있어야 한다. 따라서 추후 동수역학 및 열역학에 기초한 3차원 수치모형 연구와 성층흐름에 정밀한 밀도류 실험연구 및 이에 대한 적용이 필요할 것으로 판단된다.함으로써 정보의 질적보장과 정보전환의 표준화방안을 제시하는 정보분석시스템이다.이용, 수자원의 지속적 확보기술의 특성에 따른 4개의 평가기준과 26개의 평가속성으로 이루어진 2단계 기술가치평가 모형을 구축하였으며 2개의 개별기술에 대한 시범적용을 실행하였다.하는 것으로 추정되었다.면으로의 월류량을 산정하고 유입된 지표유량에 대해서 배수시스템에서의 흐름해석을 수행하였다. 그리고, 침수해석을 위해서는 2차원 침수해석을 위한 DEM기반 침수해석모형을 개발하였고, 건물의 영향을 고려할 수 있도록 구성하였다. 본 연구결과 지표류 유출 해석의 물리적 특성을 잘 반영하며, 도시지역의 복잡한 배수시스템 해석모형과 지표범람 모형을 통합한 모형 개발로 인해 더욱 정교한 도시지역에서의 홍수 범람 해석을 실시할 수 있을 것으로 판단된다. 본 모형의 개발로 침수상황의 시간별 진행과정을 분석함으로써 도시홍수에 대한 침수위험 지점 파악 및 주민대피지도 구축 등에 활용될 수 있을 것으로 판단된다. 있을 것으로 판단되었다.4일간의 기상변화가 자발성 기흉 발생에 영향을 미친다고 추론할 수 있었다. 향후 본 연구에서 추론된 기상변화와 기흉 발생과의 인과관계를 확인하고 좀 더 구체화하기 위한 연구가 필요할 것이다.게 이루어질 수 있을 것으로 기대된다.는 초과수익률이 상승하지만, 이후로는 감소하므로, 반전거래전략을 활용하는 경우 주식투자기간은 24개월이하의 중단기가 적합함을 발견하였다. 이상의 행태적 측면과 투자성과측면의 실증결과를 통하여 한국주식시장에

• Journal of Satellite, Information and Communications
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• v.4 no.1
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• pp.1-7
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• 2009

As the information age comes out, the aspect of future war brings about the many changes in terms of war-fighting environment. Accordingly, information superiority and intelligence-centric warfare have been important and new war-fighting concept such as NCW(network centric warfare) have been turned up. This paper proposed all-weather core-strategy communications systems guaranteeing not only the real-time transmission of the information collected in a battlefield and expansion, automation, and rapidity of a battlefield but also broadband, mobility, survivability, and flexibility. The proposed military satellite communications system is classified into wideband mass capacity link, survivability, and the system supporting OTM(on the move) communication for the real-time transmission of battlefield information. This paper analyzed the essential operation concepts and core schemes of the U.S. Army's next generation system, TSAT(Transformational Satellite Communication System). Base on the analysis results, this paper proposed that the architecture of next generation military satellite communications systems for NCW have to provide the data rate, anti-jamming capability, network control and management capability which are optimally adaptable for the wireless channel environments such as jamming and interference and to support the variety of platforms like high-speed mobile vehicles, micromini devices, super-high speed unmanned aerial vehicles. Finally, this paper also proposed that next generation military satellite communications systems need the technologies such as the adaptable multi-antenna, laser link, and next-generation anti-jamming waveform.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.21 no.3
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• pp.613-619
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• 2017

In this paper, DF(Dual Fuel) Generator modeling, which uses both conventional diesel fuel and LNG fuel, has been performed and monitoring system has been developed based on MATLAB/SIMULINK for the development of PMS(Power Management System) HILS(Hardware In the Loop Simulation). The principal components modeling of DF Generator are DF engine which provides the mechanical power and synchronous generator which convert the mechanical power into electrical power. Submodels, such as throttle body, intake manifold, torque generation and mass of LNG and diesel Quantity are used to perform DF engine. Also, governor is used for load sharing between paralleled DF generators to share a total load that exceeds the capacity of a single generator. To verify modeling of DF Generator designated ship lumped load Simulation is carried out. A validity of DF Generator has been verified by comparison between simulation results and estimated result from the designated lumped load.

• Food Science and Preservation
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• v.10 no.1
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• pp.28-31
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• 2003

For safe storage of agricultural products in the cold storage house, accurate monitoring of temperature, humidity and gas conditions is necessary. This study was conducted to develop an environmental monitoring and warning system for the cold storage house to improve safety of storage. The system developed in this study is able to monitor temperature, humidity and $CO_2$concentration in the storage house and to send alarm signal to the farmer by telephone and beeper when abnormal conditions have been occurred in the storage house. And the developed system use internet network so we can supervise storage conditions in the home. From the results of the performance test, it was found that the temperature and relative humidity can be controlled within the range of 0.5$^{\circ}C$ and $\pm$2 percent. And farmer's response was fair.

• Journal of the Institute of Electronics and Information Engineers
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• v.50 no.3
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• pp.78-87
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• 2013

NAND flash memory has been widely used as a storage medium in mobile devices, PCs, and workstations due to its advantages such as low power consumption, high performance, and random accessability compared to a hard disk drive. However, NAND flash cannot support in-place update so that it is mandatory to erase the entire block before overwriting the corresponding page. In order to overcome this drawback, flash storages need a software support, named Flash Translation Layer. However, as the high performance mass NAND flash memory is getting widely used, the size of mapping tables is increasing more than the limited DRAM size. In this paper, we propose an adaptive mapping information caching algorithm based on page mapping to solve this DRAM space shortage problem. Our algorithm uses a mapping information caching scheme which minimize the flash memory access frequency based on the analysis of several workloads. The experimental results show that the proposed algorithm can increase the performance by up to 70% comparing with the previous mapping information caching algorithm.