• Proceedings of the KIEE Conference
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• 2001.07b
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• pp.765-767
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• 2001

Linear pulse Motors(LPM) are widely used in fields where smooth linear motion is required, and their position accuracy is higher than other motors. Hybrid linear pulse motors(HLPM) are regarded as an excellent solution to positioning problems that require high accuracy, rapid acceleration and high-speed. The LPM has low mechanical complexity, high reliability, precise open-loop operation and low inertia etc. in many application areas such as factory automation speed positioning, computer peripherals and numerically controlled machine tools. This motor drive system is especially suitable for machine tools the high position accuracy and repeatability. This paper describes about that need of the embroider machine, we want to design position-scanning device for the embroidery machine. At first, to be analysed characteristics of the machine and next designed the LPM. we used the field analysis program, The finite element method(FEM) program tool is employed for calculation the force. The reluctance models will be used the magnetic permeance of air gap by static- conditions. The forces between forcer and platen have been calculated using the virtual work method.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.11 no.5
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• pp.1-7
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• 2012

The transportation is almost dependent on a single fuel petroleum with transportation energy dilemma. Hybrid Electric Vehicle(HEV) technology holds more advantages on efficiency improvements for petroleum consumption at the transportation. And bearing is recognized as the important component of gearbox. Gearboxes for HEV transmission have been ensured the highest reliability over some years in withstanding high dynamic loads. At the same time, the demands of lightweight design and cost minimization are required by thought-out design, high-quality material, superior production quality and maintenance. In order to design a reliable and lightweight gearbox, it is necessary to analyze bearing rating life methods between standard and different bearing companies with calculation methods for modification factors. In this paper, the influence of life time of bearings will be pointed out. Bearing contact stress and load stress distribution of HEV gearbox are obtained and compared with Romaxdesigner and BearinX. And the unequal wear of the left bearing for the gearbox intermediate shaft is investigated between simulation and test.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.12 no.1
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• pp.1-20
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• 2018

Service composition in the Inter-Cloud raises new challenges that are caused by the different Quality of Service (QoS) requirements of the users, which are served by different geo-distributed Cloud providers. This paper aims to explore how to select and compose such services while considering how to reach high efficiency on cost and response time, low network latency, and high reliability across multiple Cloud providers. A new hybrid multi-objective evolutionary algorithm to perform the above task called LS-NSGA-II-DE is proposed, in which the differential evolution (DE) algorithm uses the adaptive mutation operator and crossover operator to replace the those of the Non-dominated Sorting Genetic Algorithm-II (NSGA-II) to get the better convergence and diversity. At the same time, a Local Search (LS) method is performed for the Non-dominated solution set F{1} in each generation to improve the distribution of the F{1}. The simulation results show that our proposed algorithm performs well in terms of the solution distribution and convergence, and in addition, the optimality ability and scalability are better compared with those of the other algorithms.

• Journal of the Korean Institute of Telematics and Electronics A
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• v.31A no.4
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• pp.11-20
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• 1994

The error rate equation of DS-CDMA/DQPSK skgnal adopting ARQ scheme has been derived in indoor radio channel which is characterized by AWGN, multi-user interference (MUI) and Rician fading, Using the derived equation the error performance has been evaluated and shown in figures as a function of direct to diffuse signal power ratio(KS1rT), the number of active users (K), PN code sequence length (N), the number of parity bit of linear code (b), forward channel BER, and ES1bT/NS1OT. From the results it is known that in severe fading environments (KS1rT=6) the performance of DS-CDMA/DQPSK system is not reliable so it is needed to adopt techniques for improvement. When an ARQ scheme is adopted, as a method for improving error performance, the performance improves compared with that of non-ARQ scheme and the degree of improvement is proportional to the number of parity bits of linear code. As increasing the number of parity bits, system performance is improved vut system throughput efficiency must be considered. In severe fading channel Hybrid ARQ scheme is more effective than ARQ scheme. As a result, ARQ scheme is appropriate for the high-reliability data communication systems over the radio channel in which the real time processing is not required.

• Korean Journal of Adult Nursing
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• v.20 no.5
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• pp.707-718
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• 2008

Purpose: The present study was designed to understand the conceptual definition and attributes of the clinical critical thinking ability(CCTA) in nursing and to grasp the characteristics of clinical critical thinking abilities. Methods: The data were analyzed using the Hybrid model of Schwartz-Barcott and Kim(2000). Results: Having the skills and dispositions to think critically, CCTA refers to something that implies the cognizant ability to interpret contextual meanings, analyze the relationships between materials or circumstances, draw out the best conclusions, predict things using relevant information and evaluate the reliability of information and the strength of inference on the one hand and the emphatic disposition to be curious, open-minded, intellectually integral, systematic and creative and to reflect on things in contextual terms on the other. Conclusion: CCTA is characterized by clinical circumstances, such as guessing the reasons for facts, predicting things, connecting theory to practice and approaching individual situation in total terms as well as by the Korean circumstances, such as taking another person's perspective. Hence, this study proposes developing the tools to measure the clinical critical thinking ability and the strategies to improve the clinical critical thinking ability and seeking to verify their validity, on the basis of the findings.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.11 no.4
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• pp.25-30
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• 2012

The transportation is almost dependent on a single fuel petroleum with transportation energy dilemma. Hybrid Electric Vehicle(HEV) technology holds more advantages on efficiency improvements for petroleum consumption at the transportation. And bearing is recognized as the important component of gearbox. Gearboxes for HEV transmission have been ensured the highest reliability over some years in withstanding high dynamic loads. At the same time, the demands of lightweight design and cost minimization are required by thought-out design, high-quality material, superior production quality and maintenance. In order to design a reliable and lightweight gearbox, it is necessary to analyze bearing rating life methods between standard and different bearing companies with calculation methods for modification factors. In this paper, the influence of life time of bearings will be pointed out. Bearing contact stress and load stress distribution of HEV gearbox are obtained and compared with Romaxdesigner and BearinX. And the unequal wear of the left bearing for the gearbox intermediate shaft is investigated between simulation and test.

• Journal of Powder Materials
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• v.24 no.6
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• pp.494-507
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• 2017

A three-dimensional physical part can be fabricated from a three-dimensional digital model in a layer-wise manner via additive manufacturing (AM) technology, which is different from the conventional subtractive manufacturing technology. Numerous studies have been conducted to take advantage of the AM opportunities to penetrate bespoke custom product markets, functional engineering part markets, volatile low-volume markets, and spare part markets. Nevertheless, materials issues, machines issues, product issues, and qualification/certification issues still prevent the AM technology from being extensively adopted in industries. The present study briefly reviews the standard classification, technological structures, industrial applications, technological advances, and qualification/certification activities of the AM technology. The economics, productivity, quality, and reliability of the AM technology should be further improved to pass through the technology adoption lifecycle of innovation technology. The AM technology is continuously evolving through the introduction of PM materials, hybridization of AM and conventional manufacturing technologies, adoption of process diagnostics and control systems, and enhanced standardization of the whole lifecycle qualification and certification methodology.

• Transactions of the Korean Society of Automotive Engineers
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• v.20 no.5
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• pp.95-101
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• 2012

An electric water pump for engine cooling system has an advantage which particularly in the cold start, the use of the electric water pump saves fuel and leads to a corresponding reduction in emissions. The canned type electric water pump without mechanical sealing elements was selected to meet the requirements for operational reliability and life. However, the electric water pump for internal combustion engine generates much more heat loss than for hybrid electric vehicle since it is operated by the electric power of high current and low voltage. In this study, the fluid flow and thermal characteristics of the canned type electric water pump as an inverter integrated water pump has been investigated under the effects of heat generation. The analysis conditions such as outdoor air temperature of $125^{\circ}C$, water pump speed of 6000 rpm, coolant temperature of $106^{\circ}C$ and coolant flow rate of 120 L/min was used as a standard condition. Therefore, flow fields and temperature distribution inside the water pump were obtained. Also, we checked the feasibility of the canned type for the electric water pump in comparison with the mechanical seal type.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 1997.04a
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• pp.283-289
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• 1997

A 500Wh class high-speed Flywheel Energy Storage System (FESS) driven by a built-in BLDC motor/generator has been designed, which runs from 30000 to 60000rpm nominally. Due to the motor/generator inside, the flywheel rotor made of composites supported by PM/EM hybrid bearing system has a shape of bell or pendulum and thus requires accurate rotordynamic analyses and prediction of its dynamic behavior to secure the operating reliability. Rotordaynamic analyses of the flywheel rotor-bearing system revealed that the bell shaped rotor has two conical rigid-body modes in the system operating range and the first conical mode, of which nodal point lies in the radial EM bearing position, can adversely affect the dynamic response of the rotor at the corresponding critical speed. To eliminate the possibility of wild behavior of the rotor, two guide bearings are adopted at the upper end of the rotor and motor/generator. It was also revealed that the EM bearing stiffness of 0.5~1.0E+6 N/m and damping of 2000 Ns/m are favorable for smooth operation of the system around the 2nd critical speed.

• Transactions of the Korean Society of Automotive Engineers
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• v.23 no.4
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• pp.380-387
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• 2015

Various forms of passive shock absorber have developed to supplement performance which is poorer than that of active shock absorber. It is called 'Hybrid Conventional Damper (HCD)'. Frequency sensing shock absorber that this study will cover belongs to the HCD. This study aims to demonstrate that performance of frequency sensing shock absorber is superior than that of passive shock absorber. Study process is as follows. Firstly, analysis models for both passive shock absorber and frequency sensing shock absorber are developed to secure reliability. Then, elements which cause difference of ride quality are found out through comparison of hysteresis characteristics. By comparison of frequency characteristic, furthermore, damping principle of frequency sensing shock absorber is understood. Also, it determines if the absorber performs well even though maximum excitation speed is changed. Finally, the study proves that performance of frequency sensing shock absorber is superior than that of passive shock absorber after comparing change of damping power in excitation condition that various frequencies are mixed.