• Asian-Australasian Journal of Animal Sciences
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• v.24 no.1
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• pp.17-27
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• 2011

A selection experiment for reduced residual feed intake (RFI) in Yorkshire pigs consisted of a line selected for lower RFI (LRFI) and a random control line (CTRL). Longitudinal measurements of daily feed intake (DFI) and body weight (BW) from generation 5 of this experiment were used. The objectives of this study were to evaluate the use of random regression (RR) and nonlinear mixed models to predict DFI and BW for individual pigs, accounting for the substantial missing information that characterizes these data, and to evaluate the effect of selection for RFI on BW and DFI curves. Forty RR models with different-order polynomials of age as fixed and random effects, and with homogeneous or heterogeneous residual variance by month of age, were fitted for both DFI and BW. Based on predicted residual sum of squares (PRESS) and residual diagnostics, the quadratic polynomial RR model was identified to be best, but with heterogeneous residual variance for DFI and homogeneous residual variance for BW. Compared to the simple quadratic and linear regression models for individual pigs, these RR models decreased PRESS by 1% and 2% for DFI and by 42% and 36% for BW on boars and gilts, respectively. Given the same number of random effects as the polynomial RR models, i.e., two for BW and one for DFI, the non-linear Gompertz model predicted better than the polynomial RR models but not as good as higher order polynomial RR models. After five generations of selection for reduced RFI, the LRFI line had a lower population curve for DFI and BW than the CTRL line, especially towards the end of the growth period.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.25 no.3
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• pp.285-295
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• 2001

The transport phenomena in a wedge-shaped pool of twin-roll continuous caster are affected by the various operating parameters such as the melt-feed pattern, roll-gap thickness, melt-superheat, and casting speed. A computer program has been developed for analyzing the two-dimensional, steady conservation equations for transport phenomena during twin-roll continuous casting process in order to estimate the turbulent melt-flow, temperature fields, and solidification in the wedge-shaped pool. The turbulent characteristics of the melt-flow were considered using a low-Reynolds-number K-$\xi$ turbulence model. Based on the computer program, the effects of the different melt-feed patterns, roll-gap thicknesses, and superheats of melt on the variations of the velocity and temperature distributions, and the mushy solidification were examined. The results show that the liquidus line is located considerably at the upstream region, and in the lower region appear the well-mixed melt-flow and most widely developed mushy zone. Besides, the variation of melt-flow due to varying melt-feed patterns, affects mainly the liquidus line, and scarcely has effects on the solidus line in the outlet region.

• Journal of electromagnetic engineering and science
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• v.18 no.2
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• pp.101-107
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• 2018

The impedance bandwidth and radiation characteristics of an aperture-coupled microstrip line-fed patch antenna (ACMPA) with a high permittivity (${\varepsilon}_r=10$) feed substrate suitable for integration with a monolithic microwave integrated circuit (MMIC) are investigated for various feed substrate thicknesses through an experiment and computer simulation. The impedance bandwidth of an ACMPA with a high permittivity feed substrate increases as the feed substrate thickness decreases. Furthermore, the front-to-back ratio of an ACMPA with a high permittivity feed substrate increases and the cross-polarization level decreases as the feed substrate thickness decreases. As the impedance bandwidth of an ACMPA with a high permittivity feed substrate increases and its radiation characteristics improve as the feed substrate thickness decreases, the ACMPA configuration becomes suitable for integration with an MMIC.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 1992.10a
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• pp.198-203
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• 1992

There are two important variables in machining process control, which are feed and cutting speed. It is possible to improve the machining accuracy and the productivity by maintaining the optimal feed and cutting speed. IN this work, a controller is designed to achieve on-line cutting force control based on the modeling of cutting process dynamics established through step response test. Two schemes are proposed and implemented. The first is feed control under the constant spindle speed and the second is spindle speed control under the constant feed. Finally, both are proved to work properly through simulation and experimentation.

• Animal Bioscience
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• v.36 no.7
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• pp.1067-1074
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• 2023

Objective: Better feed efficiency can be achieved by selecting rabbit genotypes with lower residual feed intake (RFI) under high ambient temperatures. Methods: Two genotypes of rabbits (Jabali, Saudi local breed and imported, Spanish V-line) were used to derive RFI and to investigate the relationship between RFI and productive traits. In total, 250 animals (125 each) were housed in individual wire mesh cages in a semi-closed rabbitry. Growth performance, feed criteria, carcass evaluation, biochemical blood analysis, and immune responses were determined. Results: Superiority in growth performance, feed efficiency, carcass characteristics, and cellular immunity was recorded in the Jabali breed compared to the V-line genotype. According to regression analysis, a significant effect of daily body weight gain was found, upon computing the expected feed intake in both genotypes. Moreover, mid-body weight^0.75 had a significant effect only in the Jabali breed. Positive correlation coefficients between RFI and dry matter feed intake or feed conversion ratio were found. The same trend in this relationship between RFI and productive traits was observed in some cases for both genotypes. An opposite trend in correlations was observed in the studied genotypes for some traits. Conclusion: The results suggest that the relationship between RFI and productive traits must be taken into consideration in rabbit breeding programs under the prevailing environment. However, further studies are required to investigate the effect of rabbit genotype and environmental factors on computing RFI.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.38 no.2
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• pp.19-27
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• 2001

All accurate and efficient antenna feed model is very important for computing GPR response using the FDTD method In literature, there are several feed models such as the equivalent network in angular-frequency domain, 1-D transmission-line cell， voltage boundary condition in time domain, etc. In this paper, theoretical relationship among the models is investigated. It is found that the above three models become equivalent when a short and lossless feed line can match with its connected transmitter receiver). In view of accuracy and efficiency of the simulation, the FDTD results according to the feed models arc compared with the measured data of the receiving responses for an actual GPR system.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.9 no.5
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• pp.630-639
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• 1998

In this paper, a T-shaped microstrip feed line is proposed for a better impedance matching to the microstrip slot antenna in a various range of slot widths. It was found that the bandwidth of this antenna is proportional to the slot width. It was also found that the radiation resistance of this feed line structure is quite constant and low regardless to the slot width. A slot antenna with T-shaped microstrip feed line is analyzed by using the FDTD method. At first, the propagation process of the reflected wave and the electric field distribution in the time domain is calculated respectively. The antenna parameters also are optimized to get maximum band width, return loss, input impedance, and radiation pattern in the frquency domain by Fourier transforming the time domain results. From the computed results, the optimum slot antenna is designed and fabricated. When the slot width is 16 mm, approximately 35% of bandwidths are obtained without a matching circuit. These computed results using FDTD method were in relatively good accordance with the measured values.

• Journal of electromagnetic engineering and science
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• v.15 no.4
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• pp.239-244
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• 2015

A simple planar heptaband antenna with a coupling feed for 4G mobile applications is proposed. This antenna consists of a folded monopole and a feed strip line on the top plane and an L-shaped line with a coupling plate on the bottom plane. The antenna provides a wide bandwidth to cover the LTE/GSM/UMTS heptaband operation. The measured 6-dB return loss bandwidth is 152 MHz (820-972 MHz) in the lowfrequency band and 1,150 MHz (1,600-2,750 MHz) in the high-frequency band. The overall dimensions of the proposed antenna are $60mm{\times}105mm{\times}1.2mm$.

• ETRI Journal
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• v.9 no.1
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• pp.125-137
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• 1987

반도체 산업에서는 반도체 소자의 고집적도와 고기능화로 인하여 전반적으로 생산설비의 자동화가 급격히 발달함에 따라 생산라인의 관리자동화가 필연적으로 요구되고 있다. 이것은 컴퓨터 network에 의한 콘트롤과 자동운반 시스팀에 의한 공정제어를 실시하기 때문이다. 이러한 시스팀들의 특징은 feed forward, feed back 에 의한 정확한 공정제어와 on line, real time의 데이터 수집, 해석을 한다. 그러나 전반적인 자동화를 실현하려면 웨이퍼의 자동 handling 기술, 고성능 센서의 개발 등이 문제점으로 남아있다.

• Proceedings of the Korean Aquaculture Society Conference
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• 2003.10a
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• pp.36-36
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• 2003

In the present study, growth performances of the offspring from selected brood line were compared to those of the offspring from non-selected brood line of red sea bream. Offspring groups were mass produced separately from two brood lines, selected and non-selected Korean strain. Selected brood line have been selected by fish size for four generations (upper 5∼30% per generation) and non-selected brood line is the second generation of wild population at south sea in Korea. There's no significant difference in body length between offspring from selected and non-selected brood line during early growing stage (until 96-days old). However, offspring from selected brood line had superior body weight growth than offspring from non-selected brood line. At sea cages rearing trials with communal stocking, Offspring from selected brood line showed significantly better performance in body weight, body length, weight gain, specific growth rate and feed consumption (but not in feed conversion ratio) than offspring from non-selected brood line. At 24 months old, offspring from selected brood line grew faster 1.10 times in body length and 1.41 times in body weight than offspring from non selected brood line. The response to selection when compared to a non-selected line is on average of 10% in weight per generation at 24 months old.