• 한국농공학회논문집
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• 제60권5호
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• pp.17-27
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• 2018

The objective of this study is to identify the priority area where the nonpoint source pollution (NPS) management is required and to set up the load reduction goals for the identified priority area. In this study, the load duration curve (LDC) was first developed using the flow and water quality data observed at 286 monitoring stations. Based on the developed LDC, the priority area for the NPS pollution management was determined using a three-step method. The 24 watersheds were finally identified as the priority areas for the NPS pollution management. The water quality parameters of concern in the priority areas were the total phosphorus or chemical oxygen demand. The load reduction goals, which were calculated as the percent reduction from current loading levels needed to meet target water quality, ranged from 67.9% to 97.2% during high flows and from 40.3% to 69.5% during moist conditions, respectively. The results from this study will help to identify critical watersheds for NPS program planning purposes. In addition, the process used in this study can be effectively applied to identify the pollutant of concern as well as the load reduction target.

• 대한전자공학회논문지SD
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• 제45권9호
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• pp.65-70
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• 2008

FIR 필터에서 곱셈기는 대부분의 면적을 차지한다. FIR 필터의 설계시 개별적인 곱셈기 대신 Common Subexpression Elimination(CSE) 알고리즘을 이용하여 덧셈만으로 곱셈기를 구현할 수 있다. CSE방식은 곱셈을 이용하지 않기 때문에 보다 작은 면적으로 필터를 구현할 수 있으나 덧셈에서 발생하는 캐리의 긴 전파 시간으로 인하여 필터 연산시간이 길어지는 단점이 있다. 특히 더해지는 항의 쉬프트가 클수록 부호 확장이 많아지며 부호확장에 의해 덧셈의 면적이 커지고 계산 시간이 길어진다. 본 논문에서는 CSE 알고리즘에서 부호 확장 부분을 제거하는 방법을 제안하며 제안한 알고리즘을 이용하여 주어진 예제를 삼성 0.35u 공정으로 설계하였을 때 기존 설계 방법 보다 면적, 속도, 파워소모에서 각각 17%, 31%, 12% 의 이득이 있음을 보인다.

• 한국소성가공학회:학술대회논문집
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• 한국소성가공학회 2004년도 춘계학술대회 논문집
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• pp.35-38
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• 2004

In general, tube drawing process is composed of two steps, so called first drawing and second drawing. Drawing cracks are mainly occurred during the 2nd drawing process due to the improper drawing process. In order to analyze the reduction distribution in successive two-step drawing process, tube drawing process was simulated by finite element method. From the finite element analysis, the balance between first and second reduction is proved to be important factor to prevent drawing cracks. Hence the numerical expression was developed for tube drawing process to distribute even strain and criteria curves that can predict the safe drawing region were also proposed using this numerical formula.

• 응용통계연구
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• 제22권2호
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• pp.435-442
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• 2009

통계모형의 상호작용 효과를 분석하기 위해 비모수적인 방법인 다중인자 차원 축소(MDR) 방법을 사용해왔다. MDR 방법은 사례-대조 데이터에만 적용 할 수 있다. 본 논문에서는 연속형 데이터에도 적용 할 수 있는 더미(dummy) 변수를 활용한 MDR방법을 소개한다. 아울러 이를 통해 한우의 주요 경제형질인 등심단면적 (longissimus muscle dorsi area: LMA), 도체중(carcass cold weight: CWT), 일당증체량(average daily gain: ADC)에 영향을 주는 우수 유전자 단일염기다형성(SNP)을 규명한다.

• 전기학회논문지
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• 제60권5호
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• pp.1023-1029
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• 2011

In the industrial vision systems, image correction has great influence on the overall performance of measurement or inspection. The overall area of distorted image is usually splitted into small control areas, and each area is corrected by its control points. The performance of correction methods using control points can be improved by reduction of control areas because the computational time and memory highly depend on the number of control areas. We develop a merging algorithm that reduces control areas and preserves the correction accuracy. The algorithm merges the splitted control areas by use of quad tree method. Experimental results are presented to verify the usefulness of the proposed method.

• 전기학회논문지
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• 제56권11호
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• pp.2017-2022
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• 2007

In a memory, most power is dissipated in line of high capacitance such as decoder lines, word lines, and bit * lines. The decoder size as well as the parastic capacitances of the bit-line are going to reduce, if ROM core size reduces. This paper proposes to reduce a mathod of power dissipation for reducing ROM core size. Design result of ROM used in FFT[2], proposed method lead to up to 40.6%, 42.12%, 37.82% reduction in area, power consumption and number of Tr. respectively compared with previous method.

• 한국정보전자통신기술학회논문지
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• 제11권5호
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• pp.475-480
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• 2018

In OFDM-based systems, FFT is a critical component since it occupies large area and consumes more power. In this paper, we present a low hardware-cost and low power 512-point pipelined FFT design method for OFDM applications. To reduce the number of twiddle factors and to choose simple design architecture, the radix-$2^4-2^3$ algorithm are exploited. For twiddle factor multiplication, we propose a new canonical signed digit (CSD) complex multiplier design method to minimize the hardware-cost. In hardware implementation with Intel FPGA, the proposed FFT design achieves more than about 28% reduction in gate count and 18% reduction in power consumption compared to the previous approaches.

• Computers and Concrete
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• 제32권4호
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• pp.351-363
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• 2023

Reducing the self-weight of reinforced concrete structures problem is discussed in this paper by using two types of self-weight reduction, the first is by using lightweight coarse aggregate (crushed brick) and the second is by using styropor block. Experimental and Numerical studies are conducted on (LWAC) lightweight aggregate reinforced concrete slabs, having styropor blocks with various sizes of blocks and the ratio of shear span to the effective depth (a/d). The experimental part included testing eleven lightweight concrete one-way simply supported slabs, comprising three as reference slabs (solid slabs) and eight as styropor block slabs (SBS) with a total reduction in cross-sectional area of (43.3% and 49.7%) were considered. The holes were formed by placing styropor at the ineffective concrete zones in resisting the tensile stresses. The length, width, and thickness of specimen dimensions were 1.1 m, 0.6 m, and 0.12 m respectively, except one specimen had a depth of 85 mm (which has a cross-sectional area equal to styropor block slab with a weight reduction of 49.7%). Two shear spans to effective depth ratios (a/d) of (3.125) for load case (A) and (a/d) of (2) for load case (B), (two-line monotonic loads) are considered. The test results showed under loading cases A and B (using minimum shear reinforcement and the reduction in cross-sectional area of styropor block slab by 29.1%) caused an increase in strength capacity by 60.4% and 54.6 % compared to the lightweight reference slab. Also, the best percentage of reduction in cross-sectional area is found to be 49.7%. Numerically, the computer program named (ANSYS) was used to study the behavior of these reinforced concrete slabs by using the finite element method. The results show acceptable agreement with the experimental test results. The average difference between experimental and numerical results is found to be (11.06%) in ultimate strength and (5.33%) in ultimate deflection.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2002년도 추계학술대회 논문집 전기기기 및 에너지변환시스템부문
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• pp.369-371
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• 2002

The railway power feeding system is divided into AC power feeding system and DC power feeding system. In downtown area. DC power feeding system is used and AC power feeding system is used in intercity railway system. AC power feeding system raises a inductive disturbance that is divided into electrostatic induction and electromagnetic induction. Especially, it has a bad effect on communication lines. So inductive disturbance reduction method has been adopted in many system. In this paper, we deals with the inductive disturbance reduction method of railway power feeding system and of sides affected by inductive disturbance.

• ETRI Journal
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• 제44권3호
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• pp.379-388
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• 2022

This study proposes a novel low-complexity algorithm for computing inverse fast Fourier transform (IFFT)/fast Fourier transform (FFT) operations in binary phase shift keying-modulated orthogonal frequency division multiplexing (OFDM) communication systems without requiring any twiddle factor multiplications. The peak-to-average power ratio (PAPR) reduction capacity of an efficient PAPR reduction technique, that is, H-SLM method, is evaluated using the proposed IFFT algorithm without any complex multiplications, and the impact of oversampling factor for the accurate calculation of PAPR is analyzed. The power spectral density of an OFDM signal generated using the proposed multiplierless IFFT algorithm is also examined. Moreover, the bit-error-rate performance of the H-SLM technique with the proposed IFFT/FFT algorithm is compared with the classical methods. Simulation results show that the proposed IFFT/FFT algorithm used in the H-SLM method requires no complex multiplications, thereby minimizing power consumption as well as the area of IFFT/FFT processors used in OFDM communication systems.