• The Transactions of the Korean Institute of Power Electronics
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• v.9 no.2
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• pp.178-186
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• 2004

This paper proposes a two-phase RCD-PWM scheme which is much better than a three-phase RCD-PWM scheme from the standpoint of the broadening and linearizing effect of the power spectrum. To implement the proposed scheme and conventional scheme, the experiment based on the SAB-Cl67 micro-controller was executed. Based on the space vector modulation technique, the duty ratio of the pulses is calculated using the SAB-Cl67 and each of PWM pulses is located randomly in each switching interval. The power spectrum of the output voltage, output current, the d.c link current and the acoustic noise radiated from inverter drives are experimentally investigated. 1'hen, the performance of the proposed scheme was compared and discussed with the conventional scheme.

• Transactions of the Korean Society of Automotive Engineers
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• v.15 no.3
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• pp.91-98
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• 2007

This paper presents the induced mathematical modeling equations for evaluating the operation stability with automatic transmission of heavy duty vehicle. This theoretical approach indicates that linearized governing equations of system can be converted into eigen-value problems. if the eigen-value has positive number, we can predict the engine operating point locates an unstable operating region. To be a stable state, the unstable operating point diverges toward a stable point which is able to maintain uniform velocity. Based on the previous theoretical analysis, we carry out dynamic simulation to show the behavior of engine operating point and torque converter in transient state. As a result of the dynamic simulation, the suggested theoretical method is found to be reasonable for evaluating the operation stability of a torque converter. In addition, the numerical results explain the engine stops and fluctuating phenomenon in reality.

• Proceedings of the Korea Contents Association Conference
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• 2012.05a
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• pp.211-212
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• 2012

과거의 공항은 공공성에 중심을 두었다면 현재는 상업성에 중심을 둔 공항의 개념으로 변모해 가고 있다. 이에 전 세계 공항들은 경쟁에서 살아남기 위해 수익창출에 노력을 기울이고 있다. 현재 세계 공항들은 경쟁에서 살아남기 위해 항공수익이 아닌 비항공수익을 통해 이익을 창출하고 있다. 비항공수익인 공항면세점의 비중은 점점 커지고 있으나, 국내외로 공항면세점에 대한 연구가 그리 활발하게 이루어지지 않고 있다. 본 연구는 공항면세점의 현황을 파악하고, 단기간 마케팅 전략인 판매촉진을 활용하여 공항면세점을 활성화 시키고자 한다. 본 연구를 수행하기 위해 먼저 공항면세점에서 이용 가능한 판매촉진 유형에 대해 개념 정의를 내려 고객만족에 미치는 영향을 살핀 후 행동의도까지의 관계를 중심으로 살펴보았다. 의미 있는 변수들을 추출한 후 분석결과를 토대로 마케팅 시사점을 파악하고 향후 고객행동의 추세 및 변화를 반영하여 공항면세점의 운영 자료로서 활용되고자 하는 것이 궁극적인 목적이다. 공항면세점 이용객 표본으로 선정하여 설문조사를 실시한 후 이용객이 지각하는 판매촉진이 고객만족에 어떻게 영향을 미치는가, 그 결과 행동의도에는 어떠한 영향을 미치는 가를 AMOS 18.0을 활용하여 실증적으로 분석하고자 한다.

• Clean Technology
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• v.2 no.2
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• pp.165-175
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• 1996

Cutting fluids in machining process are one of the parameters which have serious effects on the environment. A simple method to accomplish the environmentally clean process is to evaluate the effects of cutting fluids and select one which has the least environmental load. In this research, a process planning to select the best cutting fluid is suggested considering both machinability and environmental effects. The selection criteria and evaluation method named AHP are introduced. The planning process is illustrated with drilling characterized as a heavy-duty and low-speed process. Five standard fluids are compared with respect to five environmental attributes. Compounded cutting oils are superior to water-soluble oils in both machinability and environmental effects.

• Proceedings of the KIEE Conference
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• 2004.07c
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• pp.2099-2101
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• 2004

본 연구에서 제안하는 마이크로 시스템은 열공압 방식으로 구동되고 제작비용이 저렴한 indium tin oxide (ITO) 및 polydimethylsiloxane (PDMS)로 제작되었다. 제안된 마이크로 밸브와 마이크로 펌프의 구조는 ITO 히터, SU-8 층, PDMS membrane, 그리고 PDMS 채널로 구성 되어 있다. 제안된 마이크로 펌프와 마이크로 밸브는 제작 공정 및 구조가 간단하고 값이 저렴하며, 마이크로 펌프와 마이크로 밸브를 같은 기판 위에 쉽게 직접화할 수 있는 장점을 가진다. 마이크로 밸브의 유량은 채널 폭에 비례하며 밸브가 closing 되는 전력은 채널의 폭과 상관없이 100 mW이다. 마이크로밸브의 ITO 히터의 온-오프에 따라 유량이 매우 잘 제어되었다. 제안된 마이크로 펌프의 경우, 히터의 인가 펄스 전압이 증가함에 따라 유량은 선형적으로 비례 증가함을 관찰할 수 있다. 마이크로 펌프의 최대 유량은 펄스 전압과 duty 비가 55V와 10%일 때 6 Hz에서 78 nl/min이 측정 되었다.

• Journal of Arbitration Studies
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• v.20 no.2
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• pp.151-171
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• 2010

This paper investigates the consumer arbitration practices In the U.S. The key issue in consumer arbitration is how to protect the individual consumers from the loss of their legal rights stemming from the arbitration agreement with the business. In the U.S., the major legal doctrines to protect individual consumer include the voluntary-knowing-intelligent doctrine, unconscionability doctrine, and void contract. Even though the US courts are favorable to the enforceability of arbitration agreement, they strictly apply the contract law theories in deciding the existence of arbitration agreement, providing a strong common law protection for the consumers in arbitration. However, the practices for protection of consumers in arbitration in Korea are not mature yet. If consumer arbitration is widely adopted into B to C contracts, a protective measure for individual consumer can be found in the Act of Clause Regulation providing that the business has duty to explain the relevant clause in the adhesive contracts.

• Transactions of the Korean Society of Automotive Engineers
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• v.7 no.9
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• pp.1-9
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• 1999

Liquid Petroleum Gas (LPG) has been widely used for commercial light-duty vehicles worldwide. Since LPG has a higher octane number and a lower maximum combustion temperature than gasoline , it becomes more popular fuel for reducing exhaust emissions. In tihs study, mathematical models of air intake and fuel delivery system are presented, and a PI-controller is designed for air-fuel ratio control. Hardware and software of an engine control module (ECM) are designed for an LPG engine. The ECM is built using a Motorola MC68HC05. In order to control the air-fuel ratio at stoichiometry, the PI-control algorithm is implemented in the ECM. The experiment results show the proto LPG ECM and its control scheme perform well to meet the stoichiometric air-duel ratio requirement.

• Journal of the Korean Society for Precision Engineering
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• v.14 no.12
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• pp.95-104
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• 1997

We consider controller design problem to enhance shift quality for automatic transmission. A dynamic modeling related to shifting (mainly 2-3 up-shift) is constructed and nonlinear robust controllers are designed to reduce output torque during shifting. Suggesting a new hydraulic circuit enabling the direct clutch drive, the control activity is extended and more implementable than the conventional design. The designed robust controllers overcome the unmodeled dynamics and the uncertainty embending in the system. Moreover, the dynamic effect between the clutch pressure and the PWM valve duty is considered via singular perturbation technique.

• Proceedings of the KIEE Conference
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• 2009.07a
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• pp.887_888
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• 2009

In this paper, an advanced torque control scheme of Switched Reluctance Motor (SRM) using modified non-linear logical TSF (Torque Sharing Function) based on the DITC (direct instantaneous torque control) with PWM(Pulse Width Modulation). In the proposed control scheme, a simple calculation of PWM duty ratio, switching rules from DITC and non-linear torque sharing function can reduce the torque ripple with fixed switching frequency. The proposed control scheme is verified by the computer simulations and experimental results.

• Journal of the Korean Society for Precision Engineering
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• v.16 no.2 s.95
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• pp.183-193
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• 1999

In the previous study, a module-type vibration analysis system using modular approach is developed for the purpose of analyzing the torsional vibration of vehicle driveline. In the present paper, the system is utilized to investigate the torsional vibration of the driveline of a middle duty truck. The driveline with driving condition is modeled and the torsional vibration response is simulated. The resonance 45Hz is found at engine speed 900rpm and the resultant vibration is very high. It shows favorable agreements with reference data. The effects of parameter change on torsional vibration are also investigated, so it is clarified that clutch characteristics, axle shaft stiffness are very influential on reduction of vibratio. So the countermeasure is proposed for the clutch characteristics. The reduction of torsonal vibration by 8rad/sec is obtained.