• 천문학회보
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• 제31권2호
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• pp.68.1-68.1
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• 2006

• 대한전기학회논문지:전기기기및에너지변환시스템부문B
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• 제48권11호
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• pp.632-639
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• 1999

SRM(Switched Reluctance Motor) drives require the accurate position and speed information of the rotor. These informations are generally provided by a shaft encoder or resolver. High temperature, EMI, and dust may make detection performance deteriorate. Therefore, the elimination of the position and speed sensor is desirable. In this paper, a nonlinear adaptive observer using the MRAS(Model Reference Adaptive System) is proposed. The rotor speed and position are estimated by the adaptation law using the real and estimated currents. The stability of the adaptive observer is proved by Lyapunov stability theory. The proposed methods are implemented with TMS320C31 DSP. Experimental results prove that the observer has a good estimation performance of the rotor speed and position despite of the parameter variations and loads, and the speed control can be accomplished in the wide speed range.

• 한국정보처리학회:학술대회논문집
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• 한국정보처리학회 2022년도 추계학술발표대회
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• pp.14-16
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• 2022

세계보건기구에 의해 미세먼지가 1급 발암물질로 지정됨에 따라, 건강에 미치는 영향에 대한 관심이 커지고 있다. 성장기 학생들은 학교에서 오랫동안 머무르게 되며, 따라서 교내 미세먼지는 학생들의 건강에 미치는 영향이 매우 클 수 있다. 본 연구에서는 1년동안 대상 학교에서 수집한 미세먼지 관련 데이터 및 공개된 Air Korea, 기상청 데이터를 활용하여, LSTM 기반 미세먼지 예측 모델을 개발하였다. 수집한 데이터에서 일부 오류나 결측치가 있었지만, 이를 활용한 미세먼지 예측 정확도는 충분히 가치가 있다고 판단된다.

• 천문학회지
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• 제36권1호
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• pp.21-31
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• 2003

ASTRO-F /FIS will carry out all sky survey in the wavelength from 50 to 200 ${\mu}m$. At far infrared, stars and galaxies may not be good calibration sources because the IR fluxes could be sensitive to the dust shell of stars and star formation activities of galaxies. On the other hand, asteroids could be good calibration sources at far infrared because of rather simple spectral energy distribution. Recent progresses in thermal models for asteroids enable us to calculate the far infrared flux fairly accurately. We have derived the Bond albedos and diameters for 559 asteroids based on the IRAS and ground based optical data. Using these thermal parameters and standard thermal model, we have calculated the spectral energy distributions of asteroids from 10 to 200 ${\mu}m$. We have found that more than $70\%$ of our sample asteroids have flux errors less than $10\%$ within the context of the best fitting thermal models. In order to assess flux uncertainties due to model parameters, we have computed SEDs by varing external parameters such as emissivity, beaming parameter and phase integral. We have found that about 100 asteroids can be modeled to be better than $5.8\%$ of flux uncertainties. The systematic effects due to uncertainties in phase integral are not so important.

• 천문학논총
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• 제32권1호
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• pp.193-195
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• 2017

We demonstrate the luminosity dependence of the covering factor (CF) of active galactic nuclei (AGNs), based on AKARI mid-infrared all-sky survey catalog. Combining the AKARI with Sloan Digital Sky Survey (SDSS) spectroscopic data, we selected 243 galaxies at $9{\mu}m$ and 255 galaxies at $18{\mu}m$. We then identified 64 AGNs at $9{\mu}m$ and 105 AGNs at $18{\mu}m$ by their optical emission lines. Following that, we estimated the CF as the fraction of type 2 AGN in all AGNs. We found that the CF decreased with increasing $18{\mu}m$ luminosity, regardless of the choice of type 2 AGN classification criteria.

• 한국기계가공학회지
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• 제19권9호
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• pp.40-46
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• 2020

Inspection of vehicle systems is regularly performed by the state to ensure the emission status and the safety of vehicles. Thereby, the safety and quality of life can be improved by reducing green-house gases and fine dust, which are the main causes of vehicle defects and air pollution. This study analyzed the soot measuring probes used in the free acceleration mode method, at no-load condition, looking at the efficiency of a probe to measure soot emissions from diesel vehicles. In this study, a technique that can improve the inhalation efficiency of the probe over the (a) probes and the improved (b) probes was applied to probes (c). Probe (c) involves a structure designed close to the center of the circumference of the exhaust pipe. Results showed that the suction efficiency was improved by adding a variable center unit.

• 한국산학기술학회:학술대회논문집
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• 한국산학기술학회 2009년도 추계학술발표논문집
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• pp.263-266
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• 2009

석탄광산의 선탄장(選炭場)에서 운용하는 장치들로부터 발생하는 석탄분진의 입도분포를 현장조사와 실내분석을 통하여 파악하였으며, 연구결과는 광해(鑛害)로서 작용하는 석탄분진을 포집하는 집진기(A Dust Collector)의 설계에 필요한 자료로 제시하고자 한다. 연구결과 TB업체의 분진 입도분포는 $1{\mu}m$이하의 미세(微細)입자와 $100{\mu}m$이상의 조대(粗大)입자가 차지하는 비중이 미약한 반면, 특히 $5{\mu}m{\sim}80{\mu}m$ 사이에 분포되는 분진들이 89.2%로 나타나 발생분진의 대부분을 차지하는 것으로 파악되었다. 이들 중 원심집진기에 포집된 분진은 $70{\mu}m$이하에서 89.5%인 반면 여과집진기에서 포집된 분진의 90.0%가 $20{\mu}m$이하인 것으로 나타났다. SD업체의 분진 또한 $1{\mu}m$이하와 $100{\mu}m$이상 입자는 적은 분포를 보인 반면, $5{\mu}m{\sim}70{\mu}m$사이에 분포되는 분진들이 89.6%로 나타나 발생분진의 대부분을 차지하는 것으로 파악되었다. 이들 중 여과집진기에 포집된 분진의 입도는 $30{\mu}m$이하에서 96.2%인 것으로 나타났다.

• 한국대기환경학회지
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• 제33권4호
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• pp.319-325
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• 2017

In this study, the new particulate matter emissions considering condensable PM (CPM) of stationary pollutant sources were calculated to modify the CAPSS emissions based on only filterable PMs in Seoul and Incheon. When the new calculated emissions were compared to the existing filterable PM based emissions of local governments, different contribution patterns of emission sources were found. For example, the proportion of mobile sources was high when the filterable PM was considered; however, the contribution of non-industrial sources was dominant in Seoul when the emissions of CPM were considered. Also, the proportion of energy industrial combustion and manufacturing combustion sources was significant in Incheon when CPM emissions considered. Therefore, it seems to be much desirable to consider CPM emissions for determining adequate locations of collective energy facilities and manufacturing combustion facilities in the future. In addition, CPM should be considered to solve the dust problem nationwide. The emission analysis, diagnosis, prediction and countermeasures using CPM emissions should be appropriately performed.

• International Journal of Internet, Broadcasting and Communication
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• 제10권4호
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• pp.75-82
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• 2018

Efforts to reduce damages from micro dust and harmful gases in life have been led by national or local governments, and information on air quality has been provided along with real-time weather forecast through TV and internet. It is not enough to provide information on the individual indoor space consumed. So in this paper, we propose a IoT-based Real-Time Air Quality Sensing Board Corresponding Fine Particle for Air Quality Management in Buildings. Proposed board is easy to install and can be placed in the right place. In the proposed board, the air quality (level of pollution level) in the indoor space (inside the building) is easy and it is possible to recognize the changed indoor air pollution situation and provide countermeasures. According to the advantages of proposed system, it is possible to provide useful information by linking information about the overall indoor space where at least one representative point is located. In this paper, we compare the performance of the proposed board with the existing air quality measurement equipment.

• International Journal of Precision Engineering and Manufacturing
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• 제6권3호
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• pp.51-55
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• 2005

This study addresses the contamination sensitivity test of a typical fuel pump for an automotive vehicle. The objective of the study is to find the contamination sensitivity coefficient of a fuel pump on specific contaminant particle sizes so that an optimal fuel filter could be selected. To achieve the objective, the degradation of discharge flow rate of the fuel pump is measured under the experiments of various contaminants size ranges of ISO test dust up to $80\;{\mu}m$. The fundamental theory of contamination sensitivity is introduced and the contamination sensitivity coefficients are estimated using the experimental data. Maximum contamination sensitivity coefficient of $5\chi\;10^{-6}\;L/min{\cdot}Ea$ is found in the contaminant size range of $40\;{\mu}m\~50\;{\mu}m$. The magnified picture of the surface of vane disc reveals that the abrasive wear is the principal cause of discharge flow rate degradation. Hence, this study reveals that a high efficiency filter for contaminant particles especially in the size range of $30\;{\mu}m\~70\;{\mu}m$ especially should be used to maintain the service life of the fuel filter.