• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2004.11a
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• pp.75-78
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• 2004

In an optical disk drive, a feeding system which is used to move the optical pick-up system to the target position and the proper control scheme of it are important in random access performance. Since the effect of control is directly affected by the modeling precision of the real system, the precise modeling to the real system should be acquired. Although a simple linear order modeling to the feeding system of an optical disk drive is useful in understanding of the overall dynamic characteristics, the dynamic characteristics which are belongs to the nonlinear area cannot be predicted correctly. Furthermore, the feeding system of an optical disk drive has many nonlinear characteristics such as a nonlinear friction and backlash. For this reason, the understanding of the nonlinear properties in the feeding system is very important. In this paper, the nonlinear items of the feeding system, friction and backlash, are introduced and the effect of it are investigated. Finally, the mathematical model considering the nonlinear properties is compared to the real system, and some comments of it are given.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.44 no.5
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• pp.490-498
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• 2011

Two consecutive feeding trials investigated the effects of feeding rate and pellet expansion by water-soaking on the growth performance, blood components and histology of olive flounder Paralichthys olivaceus. The first two experiments were carried out to determine the effects of pellet expansion and feeding rate. In the first experiment, growth performance, feed utilization and survival of fish were not significantly affected by pellet expansion for six weeks. There were no significant differences in hematocrit, hemoglobin, aspartate aminotransferase, alanine aminotransferase, glucose and total protein of fish fed the expanded pellet. However, whole-body lipid content of fish in the non-expanded group was significantly higher than that in the expanded group. Histological analysis of the anterior intestine revealed that fish in the expanded group had shorter and smaller mucous folds. These results indicate that pellet expansion had no beneficial effect in terms of growth performance, feed utilization and fish health. In the second experiment, weight gain and feed efficiency were significantly increased as feeding rate increased from 0 to 2.5% body weight per day (BW/d), but there were no significant differences in weight gain or feeding efficiency in fish fed the expanded pellet at ratios of 2.5% BW/d and satiation for three weeks. Plasma aspartate aminotransferase activity of fish fed the expanded pellet at a ratio of 2.5% was significantly lower than that of starved fish. Histological analysis of the anterior intestine revealed that fish in the 0% group had shorter mucous folds. Broken-line regression analysis suggested that the optimum juvenile olive flounder feeding rate was 3.5% BW/d during the low temperature season ($16-17^{\circ}C$).

• Asian-Australasian Journal of Animal Sciences
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• v.15 no.5
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• pp.658-664
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• 2002

This study was conducted to determine a proper feeding regime for lactating Holstein cows during the warm season in Taiwan. In Feeding Trial, 21 lactating Holstein cows were randomly allotted into three feeding regimes in a Completely Randomized Design. The feeding regimes were roughage fed ad libitum along with concentrate fed either twice daily (2C) or four times daily (4C), and total mixed ration (TMR) for 8 weeks. No significant differences among the three feeding regimes were found in body weight changes, and intakes in terms of dry matter, crude protein and net energy. For milk yield and 4% FCM yield, 4C were higher than the other two feeding regimes (p<0.05). No significant differences were found in milk compositions or differences noted in the yields of the respective milk components. TMR was worse than 2C and 4C (p<0.05) in milk production efficiencies in terms of dry matter intake per kg milk yield, crude protein intake per kg milk protein yield, as well as dry matter intake, net energy intake and crude protein intake per kg 4% FCM yield. Three ruminally fistulated Holstein dry cows were randomly assigned into the same three feeding regimes in a 3${\times}$3 Latin Square Design. No significant differences were found among the feeding regimes in ruminal pH, ammonia nitrogen, total VFA concentration, molar percentages of VFA, and acetic acid: propionic acid ratio (C$_2$/C$_3$). Taken all together, roughage fed ad libitum and concentrate fed four times daily was the better feeding regime for lactating cows during the warm season in Taiwan.

• Journal of the Korean Society for Precision Engineering
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• v.19 no.7
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• pp.64-70
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• 2002

The positioning system fur the ultraprecision machine tool should have nanometer order of positioning resolution. For the purpose of achieving that resolution, various feed drive devices have been proposed and currently hydrostatic lead screw and friction drive are paid attention. It is reported that an angstrom resolution can be achieved by using twist-roller friction drive. So we have manufactured ultraprecision feeding system driven by the twist-roller friction drive and perform performance assessment for problem definition and solution finding. As a result, we found that the twist-roller friction drive is mechanically suitable for ultraprecision positioning but some considerations are needed to get higher resolution.

• Aerospace Engineering and Technology
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• v.4 no.1
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• pp.179-185
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• 2005

It is an essential subject to decrease the mass of a launch vehicle for improving performance and efficiency of space launch system. Particularly, reducing the engine supporting area is necessary for high efficiency of propulsion system with clustered engine systems. The engine supporting area is related to the branch location of the oxidizer feeding line. This article deals the performance variation of the propulsion system such as the mass of the oxidizer feeding line, pressurization pressure of the oxidizer tank, and the onset of nucleation boiling in the oxidizer pipe with the branch location of the main feeding line.

• Asian-Australasian Journal of Animal Sciences
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• v.24 no.10
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• pp.1435-1439
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• 2011

This study was conducted to evaluate the effects of creep feed with different energy densities on litter performance. A total of 30 sows (Landrace${\times}$Yorkshire) and their litters were randomly assigned with 1, 2, or 3+parities into 1 of 3 treatments (10 sows). Dietary treatments were: i) CON (no creep feed), ii) LE (creep feed (DE 4,000 kcal/kg) from 5 d of age until weaning (21 d)), and iii) HE (creep feed (DE 5,000 kcal/kg) from 5 d of age until weaning). Each piglet was weighed at d 5, 10, 15, 21 (weaning), and d 7 postweaning to determine ADG. Creep feeding reduced concentrations of epinephrine, norepinephrine, and cortisol compared with those in CON group (p<0.05). Creep feeding reduced (p<0.05) the weaning-to-oestrus interval in sows. Piglets in the HE groups evidenced greater ADG (p = 0.024) and ADFI (p = 0.001) post-weaning than those in CON treatments. Creep feeding decreased (p<0.05) the suckling time of piglet in this study. In conclusion, creep feeding increased growth and feed intake of pigs after weaning. It can decrease the oestrus interval of sows. There was no difference between providing a high energy or a low energy creep fed diet to the piglets.

• Asian-Australasian Journal of Animal Sciences
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• v.13 no.4
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• pp.511-515
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• 2000

Early weaning is a means of breaking the disease cycle from sow to piglet as well as capitalising on the enormous growth potential of the pig. However, the transition from milk to dry diets results in a growth check. Feeding of supplemental milk, fermented to reduce pH and enterotoxigenic bactetial proliferation, may be a means of gradually weaning pigs on to solid feed. This study involved 216 pigs weaned from the sow at 12 days of age, allocated to groups of 6 males and 6 females per weaner pen and allowed ad libitum access to a pelleted diet. In addition, half the pigs were given supplemental fermented skim milk for the first 8 days after weaning. Feeding supplemental fermented milk increased feed intake (104 vs. 157 g DM/d, p=0.011), average daily gain (-3 vs. 112 g/d, p<0.001) and feed conversion efficiency (0.01 vs. 0.81, p=0.003) over the first 8 days after weaning. The improvements observed in the supplemented pigs continued to be augmented such that, by 42 days of age, the pigs that had received supplemental fermented milk were heavier (9.6 vs. 11.5 kg, p=0.003) than their unsupplemented counterparts. Feeding fermented supplemental milk to early-weaned pigs can improve growth performance in the immediate and subsequent post-weaning period.

• Asian-Australasian Journal of Animal Sciences
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• v.18 no.8
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• pp.1075-1079
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• 2005

The main objective of this study is to examine genetic changes in growth rate and carcass composition traits in group housed, ad libitum fed pigs, from lines of Large White divergently selected over four years for high and low post-weaning daily gain on a fixed but restricted ration. Genetic parameters for production and carcass traits were also estimated by using average information-restricted maximum likelihood applied to a multivariate individual animal model. All analyses were carried out on 1,728 records of group housed ad libitum fed pigs, and include a full pedigree of 5,324 animals. Estimates of heritability (standard errors in parentheses) were 0.11 (0.04) for lifetime daily liveweight gain (LDG), 0.13 (0.04) for daily carcass weight gain (CDG) and 0.28 (0.06) for carcass backfat (CFT). Genetic correlations between LDG and CDG were highly positive and between LDG and CFT negative, suggesting that selection for lifetime daily gain under commercial conditions of group housing with ad libitum feeding would result in favourable improvement in carcass traits. CFT showed negative genetic correlations with CDG. Correlated genetic responses evaluated as estimated breeding values (EBVs) were obtained from a multivariate animal model-best linear unbiased prediction analysis. After four years of divergent selection for 6 week post-weaning growth rate on restricted feeding, pigs performance tested on ad libitum feeding in groups exhibited changes in EBVs of 6.77 and -9.93 (g/d) for LDG, 4.25 and -7.08 (g/d) for CDG, and -1.42 and 1.55 (mm) for CFT, in the high and low lines, respectively. It is concluded that selection for growth rate on restricted feeding would significantly improve genetic performance and carcass composition of their descendants when group housed and ad libitum fed as is a common commercial practice.

• Journal of Biosystems Engineering
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• v.43 no.3
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• pp.185-193
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• 2018

Purpose: The purpose of this study was to analyze the performance factors of a rotary impact-type thresher to develop a sesame and perilla thresher, specifically to analyze the cut length of the stems and the threshing rates based on the relationship between the blade velocity and feeding speed. Methods: The materials were dried within a range of 12.3-13.0% to test the impact cut by bending. The cut lengths of the perilla and sesame stems were categorized in 6 ranges (~7.0, 7.1-10.0, 10.1-13.0, 13.1-16.0, 16.1-20.0, 20.1- (cm)). For testing the cut length and threshing rate, the upward-rotating blade velocity was varied as 11.0 m/s, 13.5 m/s, and 22.3 m/s. Feeding speeds were changed from 0.1 m/s to 2.2 m/s by the inverter connected to the feed motor. The feed rate and threshing rates without cover-casing were evaluated with the factors of thresher testing. Results: The mean cut length of the stem decreased as the blade velocity increased and/or the feeding speed decreased. As the feed rate increased up to 17.5 g/s, the cut length distributions showed no significant difference. The threshing rate was 98.9% for sesame, and flexible according to the blade velocity and feeding speed of the perilla. Conclusion: Feeding material too fast could produce longer cut stem segments, therefore, a feeding speed less than 2.2 m/s is recommended. A blade velocity of 13.5 m/s is preferable for both sesame and perilla with regard to cut length and threshing rate.

• Animal Bioscience
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• v.34 no.1
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• pp.85-92
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• 2021

Objective: The objectives of this study were to determine the in situ degradation parameters and appropriate feeding level of pineapple cannery by-products (PCB) based on the growth performance and blood parameters of growing Hanwoo (Bos taurus coreanae) steers fed various levels of PCB. Methods: Two ruminally cannulated Holstein cows were used for in situ disappearance rate measurements. Nylon bags (5×10 cm, 45 ㎛ pore size) filled with 5 g of PCB in triplicate were inserted into the ventral sac of the two cannulated Holsteins cows and incubated for 0, 2, 4, 8, 16, 24, and 48 h. A total of 16 castrated growing Hanwoo steers (12.5±0.5 months old, 302.9±25.7 kg of initial body weight [BW]) were used for the experiment. Animals were stratified by initial BW and then randomly assigned to one of four experimental diets (0%, 1.5%, 3.0%, or 6.0% of PCB, on the dry matter [DM] basis) fed for 91-d, including 30-d of adaptation. Results: Soluble fraction a of DM and crude protein (CP) was 61.9% and 86.0%, fraction b of DM and CP was 32.7% and 11.2%, and indigestible fraction c of DM and CP was 5.4% and 2.8%. The 6.0% PCB feeding group showed lower productivity compared to animals in the other treatments. Increasing the dietary level of PCB did not alter DM intake, but it was numerically lowest in the 6.0% feeding group. The gain to feed ratio was linearly decreased by increasing of PCB. The quadratic broken-line test estimated that 2.5% (DM basis) was the maximum feeding level of PCB in growing Hanwoo steers (y = 0.103 - 0.001×[1.245-x]2, R2 = 0.18). Conclusion: Diets containing up to 2.5% PCB can be fed to growing Hanwoo steers without adverse effects on growth performance.