• 한국방송∙미디어공학회:학술대회논문집
• /
• 한국방송공학회 2009년도 IWAIT
• /
• pp.498-503
• /
• 2009

As for Hadamard Transform, because the calculation time of this transform is slower than Discrete Cosine Transform (DCT) and Fast Fourier Transform (FFT), the effectiveness and the practicality are insufficient. Then, the computational complexity can be decreased by using the butterfly operation as well as FFT. We composed calculation time of FFT with that of Fast Complex Hadamard Transform by constructing the algorithm of Fast Complex Hadamard Transform. They are indirect conversions using program of complex number calculation, and immediate calculations. We compared calculation time of them with that of FFT. As a result, the reducing the calculation time of the Complex Hadamard Transform is achieved. As for the computational complexity and calculation time, the result that quadrinomial Fast Complex Hadamard Transform that don't use program of complex number calculation decrease more than FFT was obtained.

• 한국산업융합학회 논문집
• /
• 제21권6호
• /
• pp.439-444
• /
• 2018

The performance improvement in the high speed region for the sensorless based synchronous machine drive is discussed in the paper. Conventional dynamic overmodulation method in the vector controlled AC driver requires some calculation of maximum amplitude of the applying voltage vector to limit its amplitude, which leads to increase the calculation time of microprocessor. For low performance microprocessor, this might be impossible to complete the control loop within limited control time. Thus, to reduce the calculation time, the constantly limited amplitude for applying voltage vector is tried in this paper to drive sensorless based synchronous motor. Certainly, there exists some errors in amplitude and phase angle between inverter voltage and calculating voltage in the sensorless algorithm. But, this errors are too small to prevent the high speed sensorless operation within overmodulation region. The validities of the proposed method is proved by the experimental results.

• 한국건설관리학회논문집
• /
• 제17권4호
• /
• pp.95-102
• /
• 2016

공기연장에 따른 간접비 산정에 관한 연구가 최근 정량적인 부분에 집중되어 제시되고 있으며, 최근 제도개선에 관한 연구가 계속적으로 이루어지고 있다. 국내 공공 공사의 경우 발주자가 국가인 경우에는 국가계약법을, 지방자치단체인 경우에는 지방계약법을 적용받게 되는데 이러한 산정기준의 문제점에 대해 명확하게 개선방안의 요구가 있음에도 개선방안이 제시되고 있지 않아 개별 문제점에 대한 면밀한 연구가 필요한 실정이다. 본 연구는 이러한 배경에서 '국가계약법'에 따른 산정기준과 '지방계약법'에 따른 산정기준의 각 산정결과를 비교하고, 문제점을 고찰 후 현장사례를 분석하여 적정한 기준을 제시하였다. 각 규정을 고찰한 결과 기타경비 산정방식이 다르게 규정되어 있었으며 이에 따라 실제 비용이 적게는 12.37%부터 24.95%까지 차이가 발생하고 있다는 결과를 얻을 수 있었다. 이러한 문제점은 실비가 아닌 계약당시 요율을 그대로 기타경비요율로 적용하는 국가계약법에 따른산정방식의 문제점에 따른 것이며, 이에 따라 실제 비용보다 적은 공기연장 비용이 산정되는 것으로 나타났다. 이에 본 연구는 현장자료를 기반으로 적정한 기타경비 산정요율을 총공사비 대비 1일당 기타경비 요율과 간접비 대비 요율방식으로 제시하였다.

• 한국방사선학회논문지
• /
• 제9권7호
• /
• pp.487-493
• /
• 2015

전산화단층촬영에서 재구성 과정은 상당한 시간이 요구된다. 단면 영상의 품질을 높이기 매트릭스 크기를 증가시키면 재구성 시간이 매우 빠른 속도로 증가한다. 다중코어 프로세서는 오늘날 광범위하게 사용되고 있으며, 다중코어 프로세서의 다중 스레드를 이용하여 계산 시간을 줄이는 것이 가능하다. 본 연구는 다중 스레드로 CT의 재구성 시간을 개선하였다. 다중 스레드를 위해 Pthread와 OpenMP를 이용하였고, 재구성 과정에서 많은 시간이 소비되는 컨볼루션과 역투역 과정을 자세히 조사하였다. Pthread와 OpenMP 모두 스피드업과 효율성 측면에서 비슷한 성능을 나타내었다.

• Nuclear Engineering and Technology
• /
• 제52권12호
• /
• pp.2760-2770
• /
• 2020

A model for calculation of fuel temperature profile using binary gas mixture of Helium and Xenon for gap gas conductance is proposed here. In this model, the temperature profile of a fuel pencil from fuel centreline to fuel surface has been calculated by taking into account the dilution of Helium gas filled during fuel manufacturing due to accumulation of fission gas Xenon. In this model an explicit calculation of gap gas conductance of binary gas mixture of Helium and Xenon has been carried out. A computer code Fuel Characteristics Calculator (FCCAL) is developed for the model. The phenomena modelled by FCCAL takes into account heat conduction through the fuel pellet, heat transfer from pellet surface to the cladding through the gap gas and heat transfer from cladding to coolant. The binary noble gas mixture model used in FCCAL is an improvement over the parametric model of Lassmann and Pazdera. The results obtained from the code FCCAL is used for fuel temperature calculation in 3-D neutron diffusion solver for the coolant outlet temperature of the core at steady operation at full power. It is found that there is an improvement in calculation time without compromising accuracy with FCCAL.

• 한국지반공학회:학술대회논문집
• /
• 한국지반공학회 2001년도 가을 학술발표회 논문집
• /
• pp.147-158
• /
• 2001

In general, two methods have been used to predict settlement of soft ground. One method is Terzaghi's one dimensional consolidation theory which gives time-settlement relationship using the standard consolidation test results. The other is forecasting method of ground settlement to be occured in the future using in-situ monitoring data. The above both methods have some defects in application manner or in itself especially in very deep and soft clayey ground. In view of the lessons and experiences of soft ground improvement projects, several techniques were proposed for more accurate theorectical calculation of consolidation settlement as follows ; ① Subdivision of soft ground, ② Consideration of secondary compression, ③ Using the modified compression index, etc. And also, revised hyperbolic fitting method was suggested to minimize the error of predicted future settlement. In addition, revised De-Beer equation of immediate settlement of loose sandy soil was proposed to overcome the tendency to show too small settlement calculation results by original De-Deer equation. And also, considering the various effects of settlement delay in the improved ground by vertical drains, time-settlement caculation equation(Onoue method) was revised to match the tendency of settlement delay by using the characteristics of discharge capacity decreases of vertical drain with time elapse by the pattern of hyperbolic equation.

• 한국환경과학회지
• /
• 제26권12호
• /
• pp.1321-1331
• /
• 2017

This study reviewed the applicability of the existing flood discharge calculation method on Jeju Island Han Stream and compared this method with observation results by improving the mediating variables for the Han Stream. The results were as follows. First, when the rain-discharge status of the Han Stream was analyzed using the flood discharge calculation method of the existing design (2012), the result was smaller than the observed flood discharge and the flood hydrograph differed. The result of the flood discharge calculation corrected for the curve number based on the terrain gradient showed an improvement of 1.47 - 6.47% from the existing flood discharge, and flood discharge was improved by 4.39 - 16.67% after applying the new reached time. In addition, the sub-basin was set separately to calculate the flood discharge, which yielded an improvement of 9.92 - 32.96% from the existing method. In particular, the steepness and rainfall-discharge characteristics of Han Stream were considered in the reaching time, and the sub-basin was separated to calculate the flood discharge, which resulted in an error rate of -8.77 to 8.71%, showing a large improvement of 7.31 - 28.79% from the existing method. The flood hydrograph also showed a similar tendency.

• 한국광학회지
• /
• 제10권5호
• /
• pp.405-412
• /
• 1999

SSF 알고리즘의 고정된 구간을 개선하여 자동으로 구간을 선택함으로 계산시간을 줄인 Auto Z-step과, SSF 알고리즘에 사용되는 FFT 방법의 표본값을 자동적으로 줄여서 계산시간을 감소시킨 Auto T-step 알고리즘을 제안하였다. 2.5Gbps 100km 전송시 이 두 알고리즘을 사용한 것은 기존의 1km fixed step 알고리즘보다 1/120의 계산시간이 줄었고, 10Gbps 40km 전송시 최대 1/56으로 줄었으며, 오차는 모두-30㏈ 이하였다. eye diagram으로 kkm fixed step 알고리즘과 비교할 때 오차가 무시될 수 있음을 알 수 있었다.

• Journal of electromagnetic engineering and science
• /
• 제10권4호
• /
• pp.296-302
• /
• 2010

This paper proposes an approximate equation for broad bandwidth conditions in an antenna feeding probe design with a cylindrical magneto material structure (CMMS). The bandwidth calculation has been conducted according to the relation between the distance ($r_m$) between the magneto material and feeding probe, and the magneto material thickness ($t_m$) for a given ${\mu}_r$. The bandwidth of a proposed antenna with CMM feeding structure is improved about 182 %, when ${\mu}_r=20+j0.001$, in comparison with the bandwidth of an antenna without CMMS. The maximum error extent between the bandwidth calculated by the approximation equation and by the numerical calculation of the proposed antenna is about $\pm$3.2 % for ${\mu}_r=10+j0.001$. The approximation equation proposed in this study can solve the conventional problem of the complex process and the long time required for reiterative calculation, and allow simple and precise design with prediction. The accuracy of an approximated equation is compared with the results calculated by a commercial tool and verified by reasonable agreement between them.

• 대한전기학회:학술대회논문집
• /
• 대한전기학회 1998년도 하계학술대회 논문집 G
• /
• pp.2489-2491
• /
• 1998

The study of 3D image reconstruction re has developed along the progress of computer. Therfore Great deal of research on it have been done. 3D medical image reconstruction techniques are useful to figure out human's complex 3D structures from the set of 2D section. But 3D medical image reconstruction require a lot of calculation, it takes long time and expensive system. That gives a reason to the improvement of study on speed. In this paper. applying the interpolation to only the part which can appear as cube, I come up with a method that calculates the speed by reducing the a mount of calculation.