• 한국정밀공학회지
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• 제23권4호
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• pp.29-36
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• 2006

Micro drilling by high-speed air bearing spindle is very useful manufacturing technology in electronic industry For the design of high speed air bearing spindle, there are considered stability of air bearing spindle, allowable load of air bearing, run out and tooling system design for micro drill's attach and remove. According to suggested details, we designed and manufactured high-speed air bearing spindle and carried out performance estimation such as run out, temperature change in running air bearing spindle, stiffness, chucking torque. Results are follows; Run out was measured under $5{\mu}m$ at air bearing spindle revolution $20,000\sim125,000rpm$. High speed air bearing spindle's temperature rose about $20^{\circ}C$ after 5 minutes from running and then was fixed. Allowable thrust load of spindle was 17kgf. Chucking torque of collet was 15kgfcm.

• Asian-Australasian Journal of Animal Sciences
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• 제17권2호
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• pp.271-277
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• 2004

The purpose of this experiment was to study the feeding behavior and running speed under various feed deprivation lengths and social environments. Three trials were conducted. Trial 1: ten pigs were trained individually to run a course and eat their feed at the end of the course. The pigs were deprived feed for 1, 5, 10 or 20 h. Trial 2: 1. Two pigs ran and ate together. Both pigs had 5 h of feed deprivation before the run (D5). 2. Two pigs ran and ate alone, but both pigs had 5 h of feed deprivation before the run (S5). 3. Two pigs ran and ate together. Both had 1 h of feed deprivation before the run (D1). 4. Two pigs ran and ate alone and both pigs had 1 h of feed deprivation before the run (S1). 5. Two pigs ran together, one had 5 h of feed deprivation, and the other had 1 h of feed deprivation before the run (51). Trial 3: 1. On the 1st day 5 pairs of pigs had 5 h feed deprivation and could eat feed together at (B) point (D1). 2. On the 2nd day the pigs ran and ate alone at (B) point after 5 h of feed deprivation. Feed was obtainable (D2). On the 3rd to 6th days, the pigs ran in pairs after 5 h of feed deprivation and only the dominant pig ate feed at point (B). The inferior pig was chased back to room and fed there. This stage was continued for four consecutive days, d 3 to 6. In trial 1, the running speed of pigs increased with the length of feed deprivation until 10 h, then being stable afterwards. Total feeding time increased with the length of feed deprivation (p<0.001). Eating speed did not increase with the length of feed deprivation (p>0.05). In trial 2, nine of ten pigs in treatment D5 ran faster than those in S5. Seven of the ten pigs in treatment S1 ran faster than those in treatment D1. The pigs in treatment D5 had significantly higher feed intake (p<0.001) and eating speed (p<0.05) than the pigs in other treatments. In trial 3, there were significant differences on running speed between D1 and D6 (p<0.01) and between D2 and D1, D3, D4 and D5. The inferior pig ran faster in D2 but from 3 to 6 it was the dominant pig that showed the greatest speed in completing the whole course. The results demonstrated that the pigs with low feeding motivation may cause low running speed to feed and low feed intake of the neighbor when compared with pigs kept individually.

• The Journal of Asian Finance, Economics and Business
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• 제9권6호
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• pp.245-252
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• 2022

This study examines the strength of the impact of fiscal policy tools on economic wellbeing as measured by per capita income in Malaysia from 1996 to 2020. The impact of fiscal policy instruments on economic wellness, represented by real income per capita, is measured using the autoregressive distributed lags model. The speed of adjustment from short-run disequilibrium to long-run equilibrium is also measured to assess the strength of the fiscal instruments' impact on per capita income. Empirical results exhibit the existence of co-integration relationships between per capita income, tax revenue, and government spending. The findings provide strong support for the presence of a long-run positive impact on government spending and a long-run negative impact of tax revenue on per capita income. The coefficient of ECT_t-1 indicates that deviations from a short-run disequilibrium to a long-run equilibrium from the current to the future period are corrected with a speed of 76% (equivalent to a duration of 1.5-2 years to return to equilibrium). The practical and policy implication of the results is fiscal instruments play a significant role, mainly in alleviating the economic impact of the COVID-19 pandemic in the long run.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2004년도 춘계학술대회논문집
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• pp.657-662
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• 2004

This paper presented is a case study of a real compressor rotor of a refinery plant for high speed balancing of flexible rotor. The rotor was tested in the expert high-speed balancing facility established by KIMM at early 2004. The capability of the facility can reach 40000rpm in rotation speed and 8 ton in rotor weight for high-speed balancing. The facility performs multi-plane at-speed balancing using influence coefficient from the vibration data measured at two pedestals. The test rotor had exceeded permissible criteria of vibration at initial run. But by processing a low-speed balancing at 1000 rpm and six trial run trying to calculate influence coefficient of rotor to the range of operating speed, the final result of high-speed balancing revealed a remarkable reduce of vibration at pedestal of the rotor.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2000년도 제15차 학술회의논문집
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• pp.29-29
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• 2000

This paper describes the design and implementation of a high-speed navigation computer to achieve precision navigation performance with Strapdown INS. The navigation computer inputs are velocity and angular increment data from the ISA at the signal of the 2404Hz interrupt and performs the removal of gyro block motion and the compensation of high dynamic errors at the 200Hz. For high-speed and high-accuracy, the computer consists of the 68040 micro-processor, 128k Memories, FPGAs, and so on. We show that the computer satisfies the required performance by In-Run navigation tests.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1998년도 하계학술대회 논문집 A
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• pp.3-5
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• 1998

This paper presents a speed control method for the capacitor run single-phase induction motor. The equivalent circuit of a capacitor motor is analyzed using the forward and the backward components, and simple circuit equations are obtained. Simulations for the speed control are performed by adjusting the voltage magnitude of the auxiliary winding.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2010년도 춘계학술대회 논문집
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• pp.1814-1820
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• 2010

Korean Train Express (KTX) has been commercially operating and achieving elevation on transport capacity since 2004. And the first hish-speed prototype test train, HSR-350x, was developed and succeeded in testing of running over 350km/h. Now KTX-II based on HSR-350x was started in service run. The new high-speed train development project, HEMU-400x project, has started since 2007. The protype train is being designed and manufactured. After the train are developed completely, it will run on the commercial line and will be test to verify the estimated performance. The authors devised the performance evaluation method and process of the HEMU-400x prototype system. And we introduce the definite performance test items and the method to vitrificate them in this paper.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2005년도 춘계학술대회 논문집
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• pp.199-202
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• 2005

High speed milling process is emerging as an important fabrication process benefits include the ability to fabricate micro and meso-scale parts out of a greater range of materials and with more varied geometry. It also enables the creation of micro and meso-scale molds for injection molding. Factors affecting surface roughness have not been studied in depth for this process. A series of experiments has been conducted in order to begin to characterize the factors affecting surface roughness and determine the range of attainable surface roughness values for the high speed milling process. It has previously been shown that run-out creates a greater problem for the dimensional accuracy of parts created by high speed milling process. And run-out also has a more significant effect on the surface quality of milled parts. The surface roughness traces reveal large peak to valley variations. This run-out is generated by spindle dynamics and tool geometry. In order to investigate the relationship between tool setting errors and surface roughness end tilted mills were used to cut aluminum samples. The results indicate that tool setting errors have significant effects on surface roughness and cutting forces.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2006년도 춘계학술대회 논문집
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• pp.627-628
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• 2006

High speed milling process is emerging as an important fabrication process benefits include the ability to fabricate micro and meso-scale parts out of a greater range of materials and with more varied geometry. It also enables the creation of micro and meso-scale molds for injection molding. Factors affecting surface roughness have not been studied in depth for this process. A series of experiments has been conducted in order to begin to characterize the factors affecting surface roughness and determine the range of attainable surface roughness values for the high speed milling process. It has previously been shown that run-out creates a greater problem for the dimensional accuracy of pans created by high speed milling process. And run-out also has a more significant effect on the surface quality of milled parts. The surface roughness traces reveal large peak to valley variations. This run-out is generated by spindle dynamics and tool geometry. In order to investigate the relationship between tool alignment errors and surface roughness the scallop generating mechanism in the ball-end milling with tool alignement errors has been studied and simulated. The results indicate that tool alignment errors have no significant effects ell the dimension of scallops in for flat planes.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2008년도 추계학술대회 논문집
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• pp.1736-1746
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• 2008

Because present road traffic reaches to the limitation of its faculty, Korean tilting train was developed to find the solution by increasing the speed of rail road. A tilting train can run on a curved rail at high speed so it improves a speed of a rail transit without constructing a new line. Only minimum modification is necessary for a existing line. According to above requirement, Korean tilting train was developed in 2007 and the try run has been executing since April, 2007 in order to validate its safety and reliability in a service lines. And this test and estimation will be completed in 2009. After completing a try run, main parts of tilting train will be studied again to commercialize and localize including a bogie and its commercial model design will be finalized by 2012. In order to achieve the development target as mentioned above, the study have been done to improve the bogie system. As the first step to design commercialized bogie system, measurements from the try run and a dynamic analysis were used to find problems of present bogie system well. So this project is performed to decide what parts of the bogie should be modified in basis of this result.