• Journal of Welding and Joining
• /
• 제18권5호
• /
• pp.90-97
• /
• 2000

Effect of alloy elements on joinability of insert metal for liquid phase diffusion bonding of heat resistant alloys was investigated in this study. Also, optimum chemical composition of insert metal was explained using interpolation method. The insert metals utilized was commercial Ni-base amorphous foils and newly developed Ni-base filler metals with B, Si and Cr in this study. Melting point and critical interlayer width(CIW) decreased with increasing additional amount of B, Si and Cr, melting point lowering element of the insert metal. Optimized chemical composition of insert metals could be estimated by interpolation method. The optimum amount of B, Si, Cr addition into the insert metal were found to be about 3%, 4% and 3%, respectively. The measured characteristic values, melting point, microhardness in the bonded interlayer and CIW of the insert metals were the almost identical to ones of the calculated results by interpolation method.

• Journal of Biosystems Engineering
• /
• 제10권2호
• /
• pp.27-35
• /
• 1985

This study was carried out to determine the optimum size and number of farm machines for various sizes of land coverage of the cooperative farm machinery utilization systems in Korea-namely Saemaul Mechanized Farming Group (SMFG). Fifty-one SMFG were selected from 8 counties in Chonnam province, and ownership, operation and management of farm machinery were surveyed. Annual covered area, cost and the break-even-point area of farm machinery were analyzed on the bases of the surveyed data and the present governmental subsidy policy, and then the optimum level of farm machinery ownership was determined. The results are summarized as follows: 1. The break-even-point areas of the tractors of 22-23ps, 28ps and 47-50ps were estimated as 12.1ha, 15.3ha and 21.6ha, respectively. The optimum size of a tractor for land sizes of 10-20ha, 20-30ha, and 30-40ha were estimated as 22-23ps, 28ps, and 47-50ps, respectively. 2. The break-even-point area of a rice transplanter was estimated as 3.3ha. The optimum numbers of rice transplanter for land sizes of 10-20ha, 20-30ha, and 30-40ha were estimated as 2,3, and 4, respectively. 3. The break-even-point areas of a speed sprayer (attached on power tiller) and a power sprayer were estimated as 114.6ha and 15.3ha, respectively. The optimum numbers of power sprayer for land sizes of 10-20ha, 20-30ha, and 30-40ha were estimated as 2,3 and 4, respectively. A speed sprayer is desirable for an area of more than 30ha coverage. 4. The break-even-point area of a combine was estimated as 10.7ha. The optimum numbers of combine for land sizes of 10-20ha, 20-30ha, and 30-40ha were estimated as 1,2, and 3, respectively.

• 전력전자학회:학술대회논문집
• /
• 전력전자학회 1998년도 Proceedings ICPE 98 1998 International Conference on Power Electronics
• /
• pp.987-992
• /
• 1998

Solar cell has an optimum operating point to extract maximum power. To control operating point of the solar cell, a fuzzy controller has already been proposed by our research group. However, several parameters are determined by trial and error. To overcome this problem, this paper adopts Fuzzy Neural Network (FNN) for maximum power point tracking control for photovoltaic array. The FNN can be trained to perfect fuzzy rules and to find an optimum membership functions on-line.

• Journal of Biosystems Engineering
• /
• 제22권2호
• /
• pp.105-116
• /
• 1997

Using the design variables and conditions reported in the rut part of this paper, an analysis and optimum design of the tractor-rotary power driveline were carried out. The optimum design method involved 1 variable, 2 variable and multiple variable analysis performed as requested in the design process. In order to evaluate the effects of the design variables on the power transmission performance a sensitivity analysis were also conducted. the results indicated that the length and link point of the upper link, the upper hitch point of the implement master and the location of the implement input connection affect most significantly the driveline performance. The optimum design improved the performance of an exampled tractor-rotary driveline by 93% in terms of cosine ratio.

• Structural Engineering and Mechanics
• /
• 제68권5호
• /
• pp.633-638
• /
• 2018

One of the important problems in the vehicle design is vehicle handling and stability. Effective parameters which should be considered in the vehicle handling and stability are roll angle, camber angle and scrub radius. In this paper, a planar vehicle model is considered that two right and left suspensions are double wishbone suspension system. For a better analysis of the suspension geometry, a kinestatic model of vehicle is considered which instantaneous kinematic and statics relations are analyzed simultaneously. In this model, suspension geometry is considered completely. In order to optimum design of double wishbones suspension system, a multi-objective genetic algorithm is applied. Three important parameters of suspension including roll angle, camber angle and scrub radius are taken into account as objective functions. Coordinates of suspension hard points are design variables of optimization which optimum values of them, corresponding to each optimum point, are obtained in the optimization process. Pareto solutions for three objective functions are derived. There are important optimum points in these Pareto solutions which each point represents an optimum status in the model. In other words, corresponding to any optimal point, a specific geometric position is determined for the suspension hard points. Each of the obtained points in the Pareto optimization can be selected for a special design purpose by designer to create an optimum condition in the vehicle handling and stability.

• 한국측량학회지
• /
• 제27권4호
• /
• pp.445-452
• /
• 2009

항공라이다를 이용한 도시지역 3차원 모델링에 대한 연구가 활발히 진행되고 있으며, 이를 위한 최적 점밀도 결정은 도시지 역 3차원 모델링의 성과 및 효율적인 항공라이다 활용을 위해 매우 중요 하다. 본 연구는 도시지역 항공라이다의 최적 점 밀도 결정을 위해 표본 점 밀도를 선정 하였다. 각 표본 점 밀도별 DSM 및 건물 외곽선을 이용해 최적 점 밀도 결정을 위한 시각적 평가 및 정확도 검사를 실시하였으며, 도시지역 항공라이다를 위한 최적 점 밀도를 제시 하였다.

• 대한전기학회:학술대회논문집
• /
• 대한전기학회 2002년도 추계학술대회 논문집 전기기기 및 에너지변환시스템부문
• /
• pp.131-134
• /
• 2002

The optimum design technology using combind F.E.M and eauivalent circuit is so fast and accurate that it can be applied to the optimum rotor design of an inverter-fed induction motor in high efficiency motor making industry. The optimum characteristics fer a rotor slot model of a 3 phase inverter-134 nduction motor was previously verified by a time-step F.E.M. In this paper, four verification models with the design variables near the optimum point are designed to chech whether the characteristics of a slot model presented is not less than those of the near models. The outputs of whole models are analyzed in a time-step Finite Element Method and compared in the experimental test. The economical and efficient selecting method of design variables fur the computer simulation and experimental test is presented in order to assure the optimum point.

• The Journal of the Acoustical Society of Korea
• /
• 제16권1E호
• /
• pp.41-48
• /
• 1997

The very purpose of subband codec is the attainment of data rate compression through the use of quantizer and optimum bit allocation for each decimated signal. Yet the question of floating-point quantization effects in subband codec has received scant attention. There has been no direct focus on the analysis of quantization errors, nor on design with quantization errors embedded explicitly in the criterion. This paper provides a rigorous theory for the modelling, analysis and optimum design of the general M-band subband codec in the presence of the floating-point quantization noise. The floating-point quantizers are embedded into the codec structure by its equivalent multiplicative noise model. We then decompose the analysis and synthesis subband filter banks of the codec into the polyphase form and construct an equivalent time-invariant structure to compute exact expression for the mean square quantization error in the reconstructed an equivalent time-invariant structure to compute exact expression for the mean square quantization error in the reconstructed output. The optimum design criteria of the subband codec is given to the design of the analysis/synthesis filter bank and the floating-point quantizer to minimize the output mean square error. Specific optimum design examples are developed with two types of filter of filter banks-orthonormal and biorthogonal filter bank, along with their perpormance analysis.

• 한국전자파학회논문지
• /
• 제17권3호
• /
• pp.280-286
• /
• 2006

본 논문에서는 휴대 단말기의 PIFA 내장형 안테나를 설계하기 위한 최적의 급전 위치를 결정하는 방법을 나타내었다. 안테나 방사체와 접지간의 전계 크기가 클수록 방사 전력이 크게 되어 결국 이득이 증가하는 원리를 이용하였다. PIFA 내장형 안테나의 급전 위치는 슬릿 형상 및 캐리어의 물질과 구조 등과 함께 안테나 이득을 결정하는 중요한 요인이다. 본 연구에서는 급전 위치에 따라 전계 강도가 최적 급전 위치 때보다 $2{\sim}10dB$ 감소함을 보였다. Ansoft사의 HFSS 시뮬레이션을 사용하여 삼성 휴대폰에 적용된 2 모델에 대해 시뮬레이션 하였고, 모델별 최적의 급전 위치를 구하였다.

• International Journal of Precision Engineering and Manufacturing
• /
• 제9권2호
• /
• pp.3-7
• /
• 2008

Vibratory conveyors are widely used in industry to transport granular materials and products. A theoretical point mass model for vibratory conveying was studied. The results agreed well with experimental observations. The model theory included the resting, sliding and flight states of the material. Each state was considered separately when determining the equations of motion. For the coefficients of restitution, values of zero for the normal component and 0.8 for the tangential component were found to be appropriate for modeling the collisions of the granular particles with the conveying surface. The vibration angle had a large influence on the mode and rate of transport. There was an optimum vibration angle for a given set of conditions. The optimum vibration angle decreased and was better defined as the coefficient of friction increased. The results suggest the existence of an optimum dimensionless track acceleration (throw number), which does not support general industrial practice in which the track acceleration is limited when the feed cycle becomes erratic and unstable.