• Transactions of the Korean Society of Automotive Engineers
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• v.4 no.1
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• pp.63-74
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• 1996

Automatic transmission for heavy duty vehicles is a part of the power pack which includes steering and braking systems. This transmission in different from the one for passenger car. Therefore, in order to understand the trend of the important design parameters, maneuverability, acceleration performance and maximum speed, we need to analyze the total performance characteristics of the power transmission systems. In this study, modeling of the automatic transmission in heavy duty vehicle is carried out and the performance analysis method is presented. Results can be used for performance estimation data in the analysis for several combination method which determines the optimal parameters on the basis of penalty functions and weightings. And the estimation method of the important performance parameters such as engine inertia or power loss of engine by experiments is presented.

• Journal of Electrical Engineering and Technology
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• v.5 no.2
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• pp.239-245
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• 2010

Today, as power trades between generators and loads are liberalized, the uncertainty level of power systems is rapidly increasing. Therefore, transmission operators are required to incorporate these uncertainties when establishing an investment plan for effective operation of transmission facilities. This paper proposes the methodology for an optimal solution of transmission expansion plans for the long-term in a deregulated power system. The proposed model uses the probabilistic cost of transmission congestion for various scenarios and the annual increasing rates of loads. The locations and the installation times of expanded transmissions lines with minimum cost are acquired by the model. To minimize the investment risk, the Mean-Variance Markowitz portfolio theory is applied to the model. In a case study, the optimal solution of a transmission expansion plan is obtained considering the uncertain power market.

• The Transactions of the Korean Institute of Electrical Engineers A
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• v.50 no.9
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• pp.424-430
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• 2001

A multi-level optimal power flow(OPF) algorithm has been evolved from a simple two stage optimal Power flow algorithm for constrained power economic dispatch control. In the proposed algorithm, we consider various constraints such as ower balance, generation capacity, transmission line capacity, transmission losses, security equality, and security inequality constraints. The proposed algorithm consists of four stages. At the first stage, we solve the aggregated problem that is the crude classical economic dispatch problem without considering transmission losses. An initial solution is obtained by the aggregation concept in which the solution satisfies the power balance equations and generation capacity constraints. Then, after load flow analysis, the transmission losses of an initial generation setting are matched by the slack bus generator that produces power with the cheapest cost. At the second stage we consider transmission losses. Formulation of the second stage becomes classical economic dispatch problem involving the transmission losses, which are distributed to all generators. Once a feasible solution is obtained from the second stage, transmission capacity and other violations are checked and corrected locally and quickly at the third stage. The fourth stage fine tunes the solution of the third stage to reach a real minimum. The proposed approach speeds up the two stage optimization method to an average gain of 2.99 for IEEE 30, 57, and 118 bus systems and EPRI Scenario systems A through D testings.

• The Journal of the Korea institute of electronic communication sciences
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• v.19 no.3
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• pp.497-506
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• 2024

In this paper, medium-power wireless power transmission is implemented using the commercial power frequency (60 Hz). Since general magnetic induction wireless power transmission devices use more than several tens of kHz, the commercial power frequency (60 Hz) cannot be used as is. Therefore an AC/DC converter is used to convert the 60 Hz power frequency into DC, and a high-frequency power amplifier is used to convert DC into several tens of kHz. In magnetic induction wireless power transmission, the AC/DC converter and high-frequency power amplifier are removed, and a extremely low frequency wireless power transmission(ELF-WPT) system using commercial frequency consisting of only transmitting resonance tank, transmitting coil, receiving resonance tank, and receiving coil is implemented, and verified through wireless power transmission experiments.

• Proceedings of the Korea Electromagnetic Engineering Society Conference
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• 2005.11a
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• pp.29-32
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• 2005

In this paper, we present the 8 port in-phase power divider using right/left-handed transmission line. The proposed power divider splits the input power into 8 port regardless of the electrical length of transmission lines. Its size is much smaller than the conventional one. As the length of the transmission line in the power divider decreases, its bandwidth becomes wider.

• Proceedings of the KIEE Conference
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• 2006.11a
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• pp.123-125
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• 2006

본 논문은 해남-제주간 직류송전설비(HVDC)의운영 중 변환설비 제어에 사용되는 PT전원 상실에 의한 설비 불시 정지의 해결 방안으로 한국전력공사에서 연구 개발 및 운영 중인 고속도 PT자동절체기에 관한 사항이다. 특히, PT전원 상실시 HVDC가 설비 정지되는 것을 예방하기 위해 반도체소자(TRIAC)를 이용한 고속도 PT 자동절체기를 개발하여 설비 신뢰성을 확보한 내용에 대하여 고찰하였다.

• Proceedings of the KIEE Conference
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• 1998.07e
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• pp.1647-1649
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• 1998

This paper describes the power frequency voltage and its countermeasure when a 765 kV transmission line is directly connected to a 345 kV line and operated at 345 kV voltage. The summary of this result is as follows : The western route of 765 kV transmission line doesn't need any countermeasure to reduce the power frequency voltage at the receiving end. The eastern route of 765 kV transmission needs 100 Mvar(3 phase) capacity of shunt reactor at the receiving end to reduce the power frequency voltage. The use of shunt reactors in the 765 kV transmission lines has unexpected problems, one of which is induction of high voltages on a de-energized circuit of two parallel lines. This paper examined the problem of resonance on two parallel transmission circuits in one routes.

• IE interfaces
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• v.23 no.1
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• pp.58-67
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• 2010

The purpose of this paper is to present the development processes of the assembly line tester of power transmission for lift truck. Because power transmission is most important part of lift truck, all assembled powertrain parts must be inspected for operational defects, pressures and RPM. Developed assembly line tester is designed to take about 25 minutes for inspecting each assembled power transmission and located it at the end of assembled line. The assembly line no-load tester consists of three parts: (1) the driving hardware part; for installing and operating the transmission. (2) control PCB part; send data from sensors to a computer and control driving part, (3) operation software of no-load tester; for an automatic inspection or manual inspection, for database management and printing transcripts.

• Proceedings of the KIEE Conference
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• 1999.07c
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• pp.1385-1387
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• 1999

Electric power consumption is highly increasing as the social trend requiring comfortable life, the population concentration in a big city and the industrial development. Therefore it has become to be very important to supply the stable high-quality power. As these trends, the underground power transmission facilities are unavoidable in the center of a city and are going to increase more and more. As the proportion to increase facilities, the efficient management and maintenance become more important and are going to play an important role in the high-quality of power supply.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.8 no.7
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• pp.2281-2301
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• 2014

In wireless ad hoc networks the nodes focus on achieving the maximum SINR for efficient data transmission. In order to achieve maximum SINR the nodes culminate in exhausting the battery power for successful transmissions. This in turn affects the successful transmission of the other nodes as the maximum transmission power opted by each node serves as a source of interference for the other nodes in the network. This paper models the choice of power for each node as a non cooperative game where the throughput of the network with respect to the consumption of power is formulated as a utility function. We propose an adaptive pricing scheme that encourages the nodes to use minimum transmission power to achieve target SINR at the Nash equilibrium and improve their net utility in multiuser scenario.