• Journal of Communications and Networks
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• v.12 no.3
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• pp.253-265
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• 2010

The problem of pricing for a telecommunication network is investigated with respect to the users' sensitivity to the pricing structure. A functional optimization problem is formulated, in order to compute price reallocations as functions of data collected in real time during the network evolution. No a-priori knowledge about the users' utility functions and the traffic demands is required, since adaptive reactions to the network conditions are sought in real time. To this aim, a neural approximation technique is studied to exploit an optimal pricing control law, able to counteract traffic changes with a small on-line computational effort. Owing to the generality of the mathematical framework under investigation, our control methodology can be generalized for other decision variables and cost functionals.

• The Transactions of the Korean Institute of Electrical Engineers
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• v.43 no.3
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• pp.397-408
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• 1994

In this paper, a novel concept for a static three-phase to three-phase power converter for an AC drive with a unity power factor and reduced harmonics on the utility line is presented. The power circuit consists of two back-to-back connected six-pulse bridges having only a $\mu$F ceramic capacitor in the DC link. By controlling the active kpower balance between two bridges, the DC link voltage can be maintained within 20V deviation from the nominal value with the small ceramic capacitors regardless of the load variation even in the unbalanced source condition.

• Proceedings of the KIEE Conference
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• 2006.10a
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• pp.162-164
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• 2006

There are concern on possible health effects from exposure to electric and magnetic fields. One reflection of this concern is the considerable controversy, delay, and cost increases involved in the construction of utility lines and facilities. To meet such challenges, in this paper we investigated magnetic fields reduction techniqies such as general compaction, in-span compaction, cruciform, vertical, 3way splits phase, and 4way splits phase. As results, we found 1 spacer in-span compaction was appropriate in Korea in view of effectiveness and economy.

• Proceedings of the KIEE Conference
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• 2003.07a
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• pp.338-341
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• 2003

This paper proposes the adaptive relaying algorithm of protective devices applied in the neighboring distribution feeders for reliable and efficient operations of a wind farm interconnected with distribution networks by dedicated lines. Generally, it would be highly possible that the wind turbine generators are influenced by abnormal grid conditions such as disturbances occurring in the neighboring distribution feeders as well as the dedicated power line. The delayed operation time of protective devices for satisfying the coordination might overly expose the interconnected wind turbine generators to the fault and cause damage to them. In order to reduce the damages on the interconnected wind farm about the faults happening in distribution networks, this paper describes the proper delayed operation time of protective relay.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2002.05a
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• pp.57-61
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• 2002

This paper presents a current-source-inverter based on a buck-boost configuration and its application for residential photovoltaic system. The proposed circuit has five switches. Among them, only one switch acts as chopping, and the other determine the polarity of output; therefore, it can reduce the switching loss. Because the input inductor current is operated on the discontinuous conduction mode, high power factor can be achieved without additional input current controller. So the overall system shows a simple structure. The operational modes are analysed in depth, and then it was verified through the experimental results using a 150 W prototype.

• Proceedings of the KIEE Conference
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• 2003.11a
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• pp.59-61
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• 2003

This paper demonstrates an analysis of harmonics at the high speed railway substation and proved on this countermeasure using the PSCAD/EMTDC simulation tool. First, high speed railway feeding system is composed using PSCAD/EMTDC electrical railway feeding system model in advance. Second, This paper applications line capacitance values as feeder-trolley, trolley-rail and feeder-rail to analysis harmonics more accuracy in advance did not application. This capacitance values calculate using the EMTP(Electro Magnetic Transient Program). Third, the tractions are arranged in the section that substation supplies power, and this paper take the simulation each case(fractions composition amount) to see harmonic propagation from traction to substation. As a result, generated harmonics at traction can confirmed that harmonics did not reduce at utility source. This harmonics have an influence on bulk power system. Finally, this paper introduces the methods of harmonics effect minimum. This paper proved harmonics reduce effect through the passive filters application.

• Proceedings of the KIEE Conference
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• 2003.07d
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• pp.2711-2713
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• 2003

본 논문에서는 수요관리, 원격검침, 심야전력관리, 고객 부가서비스 등 여러 서비스를 단일 전력선 통신망을 이용한 지능형 전력부가 서비스 시스템을 설계하였다. 설계된 시스템은 저압 수용가에 다양한 편리 서비스를 제공함과 동시에 수용가의 전력 에너지이용을 효과적으로 하도록 유도할 수 있으며, 다수의 수용가를 하나의 통신망으로 연결하여 경제성이 우수하다.

• Journal of Korea Society of Digital Industry and Information Management
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• v.13 no.2
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• pp.71-76
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• 2017

In this study, we learned about the emergence of on-line communications originating from peoseuteol Computer Communications, the limitations of online communication, and the definition, traits and development of emoticons that serve as complementary roles, such as emotion and status. After analyzing various literacture and references, it was found that the emoticons functioned as a function of communicating the visual language of the digital era and communicating more sensitively to emotional factors. In a multimedia environment, emoticons are developed at a more advanced stage as the users' own icons due to a stronger tendency to pursue particularity and uniqueness. It is expected that eomotions added with multimedia functions will be more popular and vary in type. However, although the diversification of emotions as a commercial tool is already actively progressing, there appears a reverse effect in which an excessive use of emoticons is considered insincere in online communications. In such a background, research should be conducted that can support a systematic and effective development of emoticons through visual research rather than producing multimedia emoticons indiscreetly.

• Proceedings of the KIPE Conference
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• 2001.07a
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• pp.85-89
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• 2001

In this paper, a new line-commutated SCR inverter for renewable power generation system is proposed. The proposed inverter system includes a 6-pulse SCR inverter and an auxiliary circuit. By the proper operation of the auxiliary circuit, the pulse number of the inverter system is increased and the output harmonic currents are reduced. Analysis, control and simulation for 24 pulse operation of the proposed scheme is presented and the experimental results will be provided in the final paper.

• IE interfaces
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• v.6 no.2
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• pp.151-169
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• 1993

In this research, we proposed "coefficient of inequality" as a measure of distributional inequality for an alternative, which is defined as the area between the diagonal line from 0 to 1 and the Lorenz curve of the given alternative. Next, we showed theoretical relationship between stochastic dominance and the coefficient of inequality as a means to determine the preferred alternative when decision is made with incomplete information about decision maker's utility function. Then, two experiments were performed to test subject‘s attitude toward risk. The results of the experiments support the idea that when a decision maker is risk averse or risk prone, he/she can use the coefficient of inequality as a decision rule to choose the preferred alternative instead of using stochastic dominance. Thus, according to decision maker’s attitude toward risk, the decision rule proposed here can be used as a valuable aid in decision making under uncertainty with incomplete information.