• 제어로봇시스템학회:학술대회논문집
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• 1993.10b
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• pp.316-320
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• 1993

Electromagnetic suspension (E.M.S) type levitation system is studied in the control system design viewpoint. Dynamic characteristics in theoretical analysis as well as hardware implementation is considered. Open loop unstable, non-linear and timevarying characteristics are reviewed in the theoretcal section, while levitation control system for multi-vehicle train as well as magnet drive system is reviewed in the practical section. This paper suggests not only some well-known problem appearing in levitation control system design but also a subtle problem and solution candidates. But there exist many unmentioned problems wating for a smart problem solver.

• Transactions of the Korean Society of Mechanical Engineers
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• v.7 no.2
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• pp.138-144
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• 1983

To evaluate the dynamic characteristics of machine tool system, the system is modelled as a closed-loop system composed of cutting process and improved machine tool structures. The proposed machine tool structure model is constructed in consideration of energy transfer through the system. A new methodology to identify the machine tool dynamics by adopting impulse response and impulse cutting techniques is also proposed. It is shown that the methodology is successfully applied to a machine tool system to identify its dynamic characteristics employing the improved model.

• Proceedings of the KIEE Conference
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• 1988.11a
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• pp.36-41
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• 1988

Analog and Digital Speed Control Systems have mutually complementary properties. Analog System has good dynamic characteristics and moderate steady-state accuracy and can be implemented economically with operational a ampliers. Digital System, on the contray, has good static accuracy, but relatively poor dynamic property. So, a hybrid system which uses both digital and analog control can have good static and dynamic characteristics. In this paper, it is shown that a simple digital controller can improve steady-state accuracy of existing analog control system satisfactorily, and some design criteria are presented also.

• Proceedings of the KSR Conference
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• 2007.05a
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• pp.705-709
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• 2007

This paper introduced the system characteristics of advanced EMU to be applied in urban transit system after 2010. The system characteristics are improvements of vehicle efficiency, implementation of lightweight vehicle body, improvements of passenger's convenience, facilities for handicapped people, improvements of system reliability, strengthening national competitiveness.

• Proceedings of the Korean Nuclear Society Conference
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• 1995.10a
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• pp.413-418
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• 1995

A computer code to simulate the letdown system was developed to analyze the hydrodynamic transients. It was found that valve plug characteristics have a significant effect on the system stability, and that the plant specific valve control system setpoints should be determined based on the characteristics of procured valves by using a simulation code, before performing the plant startup test. The letdown system instability was evaluated for the feedback to the design of future plants.

• Proceedings of the KIEE Conference
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• 1998.07g
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• pp.2436-2438
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• 1998

The operating characteristics of a 3 kW grid-connected photovoltaic (PV) power system was studied by analying annual photovoltaic data. The system performance for grid connection was investigated using a DC/ AC inverter. The results of a demonstration test show that the system utilization rate is 15.6% and the system efficiency is 8.03%.

• Journal of Information Technology Services
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• v.14 no.4
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• pp.171-184
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• 2015

Nowadays, mobile commerce is having an increasingly profound impact on our daily lives, and offer interesting and advantageous new services. Mobile payment is an emerging and important application of mobile commerce in smart work, enabling users to use their mobile devices (especially mobile phones) for paying goods and services wherever they go. The appearance of m-payment is expected to provide us a convenient and bright future to enjoy. That is the common trend on over the world, but in Vietnam, although the number of smart phone users has been increasing rapidly, the adoption of m-payment system still didn't succeed completely. The research reviewed literature regarding mobile payment services, analyzed the impact of customer characteristics and system characteristics on m-payment adoption in Vietnam. To analyze the adoption behaviors of m-payment users, m-payment research model which consists of three customer-characteristics (m-payment trust, personal innovativeness, m-payment knowledge) and four m-payment system characteristics (mobility, reachability, convenience, compatibility) were studied. The results indicate that perceived usefulness, trust, and compatibility are the important predictors to the intention to use m-payment. This study will assist m-payment services suppliers in implementing appropriate business models and service strategies to successfully attract customer to use m-payment in Vietnam, allowing managers to exert appropriate investment, time, and effort for m-payment system development in designing smart working.

• Proceedings of the KSME Conference
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• 2004.04a
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• pp.1534-1539
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• 2004

The objective of this study is to simulate the etching characteristics with oscillation angle for the optimization of etching system. The etching characteristics were analyzed under different etching conditions. The spray characteristics were measured by Phase Doppler Anemometer (PDA). The correlation between the spray characteristics and the etching characteristics was investigated and used for fundamental data to simulate the etching characteristics with oscillation angle. The smaller coefficient of variation, the more uniform etching characteristic distribution became. It was found that numerical predictions of etching factor generally agreed well with the measured results with distance from nozzle tip. Oscillation leads to decrease of etching factor and increase of uniformity.

• The Journal of Industrial Distribution & Business
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• v.11 no.2
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• pp.17-23
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• 2020

Purpose: The purpose of this study is to understand the effect of the unique product recommendation system on customer satisfaction. Research design, data and methodology: The survey method used the self-recording way in which the respondents selected for the study and distributed 300 questionnaires, and with due personal care, researchers collected all the distributed questionnaires. Results: The result implies that the characteristics of the product recommendation system should be more secure and developed. Conclusions: The aspects of the product recommendation system were selected as factors of price fairness, accuracy, and quality through previous studies, and the empirical analysis of the effect of the characteristics of the product recommendation system on customer satisfaction was summarized as follows. Among the attributes of the product recommendation system, the attributes of price fairness, accuracy, and quality affect customer satisfaction. Among them, the beta value of quality was the highest, and the effect of quality was the largest among the three factors. Based on the results of the study, the implications for the characteristics of the product recommendation system are summarized as follows. The aspects of the product recommendation system have a positive effect on customer satisfaction, so it is necessary to fill the needs of consumers based on the survey focused on quality

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.19 no.3
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• pp.346-352
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• 2010

Recently, the high-tech industries, such as the aerospace industry, the auto industry, and the electronics industry, are growing up considerably. Because of that, high machining accuracy and productivity of precision parts have been required. The tooling system is important part in the machining center. HSK tooling system is more suitable than BT tooling system for that of high speed machining center. It is because static stiffness and machining accuracy of HSK tooling system are higher than those of BT tooling system. In this paper, static and dynamic behavior of the HSK tooling System is analyzed according to bearing characteristics and lightweight parts. In order that, three different models of the HSK tooling system are modelled by using a 3D modeling/design program. More stable one in the models of HSK tooling system can be selected by using the FEA(Finite Element Analysis).