• Proceedings of the Korean Society of Precision Engineering Conference
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• 1997.10a
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• pp.79-82
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• 1997

The current from the feed motor of a machine tool contains substantial information about the machining state. There have been many researches that investigated the current as a measure for the cutting forces. However it has not been reported that indirect measurement of the cutting forces from the current of the feed motor at rest is possible. The cutting force normal to the machined surface influences the machined surface of the workpiece, which makes it necessary to estimate this force to control the roughness of the machined surface. But the unpredictable behavior of the current prevents applying the current to prediction of the cutting state. In this paper, empirical approach was conducted to resolve the problem. Also parametric adaptive and fuzzy logic control strategies are applied to the force regulation problem. As a result, the current is shown to be related to the accumulation of the infinitesimal rotation of the motor, and besides the unpredictable behavior of the current is shown to be caused by the relationship. Subsequently the relationship between the current and the cutting force is identified, and it is presented that control of machined surface using the current of the feed motor at rest is possible.

• Journal of Power Electronics
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• v.13 no.3
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• pp.400-408
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• 2013

This paper presents a discrete state-space controller using state feedback control and feed-forward decoupling to provide a desirable control bandwidth and control stability for dynamic voltage restorers (DVR). The paper initially discusses three typical applications of a DVR. The load-side capacitor DVR topology is preferred because of its better filtering capability. The proposed DVR controller offers almost full controllability because of the multi-feedback of state variables, including one-beat delay feedback. Feed-forward decoupling is usually employed to prevent disturbances of the load current and source voltage. Directly obtaining the feed-forward paths of the load current and source voltage in the discrete domain is a complicated process. Fortunately, the full feed-forward decoupling strategy can be easily applied to the discrete state-space controller by means of continuous transformation. Simulation and experimental results from a digital signal processor-based system are included to support theoretical analysis.

• 제어로봇시스템학회:학술대회논문집
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• 2000.10a
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• pp.251-251
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• 2000

Tangjin Power Plant is modern Korean standard plant which is made up Once Through Super Critical Boiler, Turbin, Generator and Flue Gas Desulfarization System. INFI-90 system fur control of the 500 MW Korean standard super critical once through boiler Mark-V for Turbine, EX-2000 fer Generator, WDPF for FGD were installed in Tangiin thermal power plant. There were two BFPTs, BFPM, 25% control valve, 35% control valve to control boiler feed water flow. It is very difficult to tune the Separator Tank level control system and change the mode from Wet to Dry. This paper focuses on test results and modification control logic for feed water control system in Tangjin power plant.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2012.10a
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• pp.63-64
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• 2012

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.19 no.1
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• pp.49-55
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• 2020

Studies on the optimizations of machining processes use two different methods. The first is feed control in real-time by spindle load in a machine tool. The second is feed scheduling in NC code control by material removal rate using a CAD/CAM system. Each approach possesses its respective merits and issues compared to the other. That is, each method can be complementary to the other. The purpose of the study is to improve the productivity of the bulkhead, an aircraft Duralumin structure. In this paper, acceleration or deceleration of cutting tool by spindle load data is achieved using adaptive feed control macro programming in a machine tool.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 1999.05a
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• pp.123-127
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• 1999

This paper suggests the establishment of high-accuracy and high-efficiency machining method of scroll shape workpiece by using the feed control method. The cutting paths for machining the inside and outside surfaces of the scroll-shape workpiece are calculated, and the calculation method of the cutting chip areas based on the coordinate of the base circle is shown. A feed control method is proposed for a constant cutting area and cutting force. By machining test of scroll shape workpiece, The machined accuracy of wrap, tool wear, and surface roughness are evaluated. By this method, Reduction of the machining time and large increase of the efficiency can be expected.

• Procedding of Korea Feed Ingredients Association Conference
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• v.1
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• pp.61-75
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• 2000

• Asian-Australasian Journal of Animal Sciences
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• v.23 no.11
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• pp.1427-1435
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• 2010

The present study was conducted to examine the effect of a stair-stepped feed intake pattern on growth, feed efficiency, and meat quality of Hanwoo steers. Twenty-seven 11-month-old Hanwoo steers were randomly divided into three groups. The control group was fed according to the Korean steer feeding program, and the other two groups were fed according to an alternated feeding schedule of 3-2-4-2 months. During the first three months of the experiment, treatment group 1 (T1) and treatment group 2 (T2) were fed 20% and 30% less than the control group, respectively. For the following two months, the T1 group was fed 20% more than the control group while the T2 group was fed 20% less than the control group. In the third step, T1 and T2 groups were fed 20% and 10% less, respectively, than the control group for four months. In the last two months, T1 and T2 groups were fed 20% more than the control group. After the stair-step feeding trial, steers were fed concentrated feed ad libitum for five months. The altered feed intake pattern did not affect daily body weight gain. However, daily feed intake tended to decrease and growth efficiency tended to increase in the two treatment groups compared to the control group. Altered feed intake also affected blood metabolite levels. The serum glucose and BUN level of the T1 group increased in the first re-fed period compared to the T2 and control groups. The serum cholesterol level of the T2 group decreased in the first restricted-re-fed growth period compared to the T1 and control groups. The serum NEFA levels of the two treatment groups increased from the first restricted period compared to the controls. The serum insulin level of the T2 group increased in the last period compared to the T1 and control groups. Regarding meat yield index, the control group was significantly higher than the T2 group (p<0.05). Regarding meat yield grade, the carcass back fat thickness of the T2 group was significantly higher than the control group (p<0.05). In marbling score, the T1 group was the highest (4.9), followed by the control group (4.1) and the T2 group (4.0). These results indicate that using a stair-stepped growth pattern (T1) can contribute to improvements in growth efficiency and muscle marbling.

• Asian-Australasian Journal of Animal Sciences
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• v.29 no.10
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• pp.1470-1476
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• 2016

Octacosanol, which has prominent physiological activities and functions, has been recognized as a potential growth promoter in animals. A total of 392 1-d-old male Arbor Acres broiler chicks with similar body weight were randomly distributed into four dietary groups of seven replicates with 14 birds each supplemented with 0, 12, 24, or 36 mg octacosanol (extracted from rice bran, purity >92%)/kg feed. The feeding trial lasted for six weeks and was divided into the starter (day 1 to 21) and the grower (day 22 to 42) phases. The results showed that the feed conversion ratio (FCR) was significantly improved in broilers fed a diet containing 24 mg/kg octacosanol compared with those fed the control diet in the overall phase (day 1 to 42, p = 0.042). The average daily gain and FCR both showed linear effects in response to dietary supplementation of octacosanol during the overall phase (p = 0.031 and 0.018, respectively). Broilers fed with 24 or 36 mg/kg octacosanol diet showed a higher eviscerated yield, which increased by 5.88% and 4.26% respectively, than those fed the control diet (p = 0.030). The breast muscle yield of broilers fed with 24 mg/kg octacosanol diet increased significantly by 12.15% compared with those fed the control diet (p = 0.047). Eviscerated and breast muscle yield increased linearly with the increase in dietary octacosanol supplementation (p = 0.013 and 0.021, respectively). Broilers fed with 24 or 36 mg/kg octacosanol diet had a greater (p = 0.021) $pH_{45min}$ value in the breast muscle, which was maintained linearly in response to dietary octacosanol supplementation (p = 0.003). There was a significant decrease (p = 0.007) in drip loss value between the octacosanol-added and the control groups. The drip loss showed linear (p = 0.004) and quadratic (p = 0.041) responses with dietary supplementation of octacosanol. These studies indicate that octacosanol is a potentially effective and safe feed additive which may improve feed efficiency and meat quality, and increase eviscerated and breast muscle yield, in broiler chicks. Dietary supplementation of octacosanol at 24 mg/kg diet is regarded as the recommended dosage in the broilers' diet.

• Asian-Australasian Journal of Animal Sciences
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• v.18 no.8
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• pp.1164-1170
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• 2005

This study was conducted to evaluate performance, breast (thigh) muscle yield, nutrient digestibility and serum biochemical parameters of broilers fed low-protein diets supplemented with various threonine to lysine ratios (Thr/Lys). Three hundred and twenty four day-old male Arbor Acres broilers were randomly allotted to six dietary treatments with six replicates per treatment and nine broilers per replicate. Six treatments included one control diet [formulated according to NRC (1994)], and five experimental diets (treatments 1-5). In treatments 1-5, the crude protein level was 2% lower than that of the NRC control diet. The Thr/Lys in treatments 1-5 was 0.65, 0.70, 0.75, 0.80 and 0.85 during the starter and grower phases and 0.70, 0.75, 0.80, 0.85 and 0.90 during the finisher phase with other nutrient levels kept consistent. The results showed that: (1) With increasing Thr/Lys, ADG of treatments 1, 3 and 4 were lower (p<0.05) than those of the NRC control diet during the starter phase; ADG of treatments 1-5 were lower (p<0.05) than those of the NRC control during the grower phase, and ADG of treatment 1 was lower (p<0.05) than that of the NRC control during the finisher phase. Average daily feed intake in treatments 1 and 4 were lower (p<0.05) than that of broilers on the NRC control diet during the grower phase. Feed/gain (F/G) of the NRC control diet was lowest (p<0.05) during the starter phase. F/G in treatments 2 and 5 were higher (p<0.05) than that of NRC during the grower phase. (2) Breast muscle proportion on d 21 increased linearly (p<0.05) in response to graded levels of Thr/Lys. (3) No differences were detected for dry matter, energy and crude protein digestibility among all seven treatments. (4) On d 21, serum triglyceride of broilers on dietary treatments 3 and 5 was higher (p<0.05) than that of broilers in control. The results indicate that the low-protein diets supplemented with an appropriate Thr/Lys could not support the same performance that was achieved by the broilers fed the NRC control diet.