• 신재생에너지
• /
• 제3권3호
• /
• pp.54-62
• /
• 2007

The present paper describes the scale effect correction methods for scaled NREL Phase VI wind turbines by using CFD[computational fluid dynamics). For the corrections of wind turbine scale effect, various researches on the helicopter rotor scale effect were investigated and the feasibility study of the methods was performed to correct wind turbine scale effect. The present paper also introduces scale effect correction methods based on two dimensional lift slope. In order to test the present method, performance analyses of NREL Phase VI wind turbines under various scale conditions were carried out and new correction method was applied. Granting that the new correction method is valid only above Reynolds No. 100,000, it showed reasonable agreement between model and full scale wind turbines in the linear torque region.

• 대한디지털의료영상학회논문지
• /
• 제12권1호
• /
• pp.51-58
• /
• 2010

Ionization chambers often exhibit a stem effect, caused by interactions of radiation with air near the chamber end, or with dielectric in the chamber stem or cable. In this study measured stem effect correction factor for length of ionization chamber from medical linear accelerator recommend to with the use of stem correction method. For a model of the Farmer-type chamber, were used to calculate the beam quality correction factor. These interactions contribute to the apparent measured exposure. Additionally, it needs to consider ionization chamber use of small volume and stem effect of cable by a large field. Linear accelerator generated photons energy and increased dose repeatedly measured by using stem correction method. Stem effect was dependence of the energy and increases with photon energy conditions improved of beam quality. In conclusion, stem effect correction factor was measured within 0.4% calculated according to the exposures stem length and also supposed to determined below 1% of another stem correction method.

• 한국항공우주학회지
• /
• 제37권4호
• /
• pp.372-382
• /
• 2009

자체 개발한 SBAS 보정정보 처리 프로그램을 이용하여 MSAS 궤도 보정정보의 정확도를 분석하고, MSAS 전리층 보정정보 대한 적도변이의 영향을 분석하였다. 또한 MSAS 보정정보의 일부분의 제거를 통해 보정정보의 수신지연으로 인한 정확도 저하와 그것이 Protection Level에 미치는 영향을 분석하였다. 그리고 국내에서 MSAS 보정정보를 이용하여 항공기 정밀접근 시 시스템의 무결성 및 가용성에 대해 분석했다.

• 한국신재생에너지학회:학술대회논문집
• /
• 한국신재생에너지학회 2006년도 추계학술대회
• /
• pp.241-244
• /
• 2006

The present paper describes the scale effect correction method for wind turbine by using CFD(computational fluid dynamics). For the correct ions of wind turbine scale effect, various researches on the helicopter rotor scale effect were Investigated and feasibility study of methods was performed to correct wind turbine scale effect The present paper also introduces new scale effect correction method based on two dimensional lift slope modification. In order to test the Present method, performance analyses of NREL Phase VI wind turbines under various scale conditions were carried out by using CFD. The present method showed reasonable results when applied to NREL Phase VI wind turbine.

• Journal of Power Electronics
• /
• 제5권1호
• /
• pp.62-66
• /
• 2005

A simple fault correction method for rotor position detection of a brushless DC(BLDC) motor with trapezoidal back EMF(electromotive force) using a Hall effect latch unit is presented. The reason why the Hall effect latch unit does not operate properly during the startup of a BLDC motor is thoroughly explained. To solve this problem, a simple code change method and its hardware implementation issues are proposed and discussed.

• 한국산업보건학회지
• /
• 제5권1호
• /
• pp.59-67
• /
• 1995

현재 국내에서 원자흡광법에 의한 혈중연 분석은 분석선 283.3 nm에서의 $D_2$ 보정 방식을 이용한 흑연로 원자흡광법이 주로 이용되고 있으며, 일반적인 시료중 납에 관한 분석은 217.0 nm에서의 $D_2$ 보정 방식이 보편화되어 있다. 그러나 이들 방식은 바탕 보정에 제한성 때문에 새로운 바탕 보정법에 대해 관심을 가지게 되었다. 그러던 중 1980년대 말부터 혈중연 분석자들은 연 분석에 있어 Zeeman effect 보정방식이 보다 좋은 결과를 나타낸다 하여 이 방법에 대하여 관심을 갖게 되었다. 따라서 본 연구는 국내 대부분의 혈중연 분석기관들이 보유하고 있는 $D_2$ 보정방식 (217.0과 283.3 nm)의 혈중연 측정결과를 편광 Zeeman effect 보정방식의 측정 결과와 비교함으로서 현재 사용 중인 기기 들의 측정결과의 타당성을 검토하기 위하여 시도하였으며 다음과 같은 결과를 얻었다. Zeeman형의 바탕보정 방식을 사용하는 기기의 결과를 편의상 1.00으로 하고, $D_2$ 형 보정 장치의 217.0 nm와 283.3 nm에서의 결과를 짝비교 (paired t-test)를 하였을 때 혈중연 농도가 $20.0{\mu}g/dl$ 이하인 경우에 0.92와 0.90으로 Zeeman형보다 낮은 값으로 분석되었으며 통계적으로 유의하였다.(P<0.001). $20.1-40.0{\mu}g/dl$인 군에서는 $D_2$ 보정방식의 결과간에 차이는 없었다. Zeeman 및 $D_2$ 보정방법에서는 혈중연 증가에 따른 바탕보정장치의 변동이 적었고 혈중연 이외의 다른 금속 즉, 철, 구리, 아연에서는 바탕보정장치에 관계없이 철은 역상관인 것으로 나타났으며, 구리와 아연은 정상관을 갖는 것으로 나타났다. 연구 결과로 미루어보아 두방법간의 차이가 없으므로 혈중연 분석에 있어서 Zeeman형 바탕보정 장치를 사용하거나 $D_2$ 바탕보정 방식(217.0, 283.3nm)의 기기를 사용하여도 무난할 것으로 생각된다.

• Genomics & Informatics
• /
• 제6권4호
• /
• pp.231-234
• /
• 2008

Precise and reliable identification of CNV is still important to fully understand the effect of CNV on genetic diversity and background of complex diseases. SNP marker has been used frequently to detect CNVs, but the analysis of SNP chip data for identifying CNV has not been well established. We compared various normalization methods for CNV analysis and suggest optimal normalization procedure for reliable CNV call. Four normal Koreans and NA10851 HapMap male samples were genotyped using Affymetrix Genome-Wide Human SNP array 5.0. We evaluated the effect of median and quantile normalization to find the optimal normalization for CNV detection based on SNP array data. We also explored the effect of Robust Multichip Average (RMA) background correction for each normalization process. In total, the following 4 combinations of normalization were tried: 1) Median normalization without RMA background correction, 2) Quantile normalization without RMA background correction, 3) Median normalization with RMA background correction, and 4) Quantile normalization with RMA background correction. CNV was called using SW-ARRAY algorithm. We applied 4 different combinations of normalization and compared the effect using intensity ratio profile, box plot, and MA plot. When we applied median and quantile normalizations without RMA background correction, both methods showed similar normalization effect and the final CNV calls were also similar in terms of number and size. In both median and quantile normalizations, RMA backgroundcorrection resulted in widening the range of intensity ratio distribution, which may suggest that RMA background correction may help to detect more CNVs compared to no correction.

• 한국임상보건과학회지
• /
• 제4권4호
• /
• pp.737-741
• /
• 2016

Purpose. To investigate awareness of vision correction surgery side effects and investigated side effects affect vision correction surgery decisions. Methods. This study was performed on 85 college students. The awareness of vision correction surgery, the awareness of vision correction surgery side effects, and investigated side effects affect surgery decisions. Results. 37.6 % (32 people) replied that the drying effects is representative side effects of the eye correction surgery. 68.2% (58 people) answered the reason of eye surgery is uncomfortable wearing glasses. 74.1%(63 people) answered the side effects does not affect vision correction surgery decision. Prior to hear a description of side effects, 31.8% percent people hope the surgery. after listening to explain of side effects, only 10.6% percent people hope the surgery. Conclusions. People who want to get vision correction surgery should check their vision condition through prior examination and consultation. What side effects in the operation should be reviewed. That is the only way to reduce side effects.

• Nuclear Engineering and Technology
• /
• 제52권6호
• /
• pp.1266-1270
• /
• 2020

A code is developed to correct for the coincidence summing effect in detecting a voluminous gamma source, and this code is applied to a¹⁵²Eu standard source as a test case. The source is 1000 mL of liquid in a cylindrical shape. To calculate the coincidence summing effect, the cylindrical source is considered as 10(radial) × 8(height) sectional sources. For each sectional source, the peak efficiency and total efficiency are obtained by Monte Carlo simulation at each energy for 10 energies between 50 keV and 2000 keV. The efficiencies of each sector are then expressed as polynomials of gamma energy. To calculate the correction coefficients for the coincidence summing effect, the KORSUM code is used after modification. The magnitudes of correction are 4%-17% for the standard ¹⁵²Eu source measured in this study. The relative deviation of 4.7% before the coincidence correction is reduced to 0.8% after the correction is applied to the efficiency based on the measured gamma line. Hence, this study has shown that a new method has been developed that is applicable for correcting the coincidence effect in a voluminous source, and the method is applied to the measured data of a standard ¹⁵²Eu cylinder source.

• 한국지구과학회지
• /
• 제30권5호
• /
• pp.550-564
• /
• 2009

When magnetotelluric (MT) data are obtained in the vicinity of the coast, the surrounding seas make it difficult to interpret subsurface structure, especially the deep part of the subsurface. We introduce an iterative method to correct the sea effect, based on the previous topographic correction method that removes the distortion due to topographic changes in seafloor MT data. The method first corrects the sea effect in observed MT impedance, and then inverts corrected response in a model space without the sea. Due to mutual coupling between the sea and the subsurface structure, the correction and inversion steps are iterated until the changes in each result become negligible. The method is tested for 1- and 2-D structures using synthetic MT data produced by 3-D forward modeling including surrounding seas. In all cases, the method closely recovers the true structure assumed to generate synthetic responses after a few iterations.