• Proceedings of the KIEE Conference
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• 2001.11b
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• pp.302-304
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• 2001

계통의 최적 조류 계산(Optimal Power Flow)을 수행한 후, 계통 전체의 ATC(Available Transfer Capability)를 구한다. 이때 계통 전체의 ATC는 어느 특정한 선로의 ATC 값으로 결정되는데, 이 선로의 전력 조류량을 조금만 줄여도 전체 계통의 ATC가 크게 증가하게 되는 경우가 많다. 따라서 본 논문에서는 계통 전체의 ATC 증대를 위하여, ATC를 제한하게 되는 관심 선로의 조류에 각각의 발전기가 미치는 민감도와 각각의 발전기의 발전비용 함수를 동시에 고려한 최적의 발전력 재분배를 통하여 발전비용의 증가와 관심 선로의 전력 조류감소 효과의 최적화를 위하여 Liner Programing 기법을 이용한다.

• Journal of Digital Contents Society
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• v.5 no.3
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• pp.171-175
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• 2004

In this paper, We applied CCI canceller to remove multi-user interference in co-channel environment and improved performance of TH PPM UWB-IR system. As a result, We could get reception performance that data transmission of high speed is available in small reception power applying CCI canceller. Also, We could get permission available channel capacity to maximum access number 40 in high speed transmission environment more than 100Mbps.

• ETRI Journal
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• v.27 no.4
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• pp.449-452
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• 2005

The electrical characteristics of solid state devices such as the bipolar junction transistor (BJT), metal-oxide semiconductor field-effect transistor (MOSFET), and other active devices are altered by impinging photon radiation and temperature in the space environment. In this paper, the threshold voltage, the breakdown voltage, and the on-resistance for two kinds of MOSFETs (200 V and 100 V of $V_{DSS}$) are tested for ${\gamma}-irradiation$ and compared with the electrical specifications under the pre- and post-irradiation low dose rates of 4.97 and 9.55 rad/s as well as at a maximum total dose of 30 krad. In our experiment, the ${\gamma}-radiation$ facility using a low dose, available at Korea Atomic Energy Research Institute (KAERI), has been applied on two commercially available International Rectifier (IR) products, IRFP250 and IRF540.

• Proceedings of the KIPE Conference
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• 2012.07a
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• pp.250-251
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• 2012

This paper proposes a new secondary battery charger/discharger available for zero voltage discharge which is used for test equipments and formation. The proposed system is able to discharge the battery to zero voltage which does not matter to voltage drop of circuit. The validity of proposed system is verified by experiment.

• Proceedings of the KIEE Conference
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• 2004.11b
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• pp.169-171
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• 2004

Available transfer capability(ATC) is an important indicator of the usable amount of transmission capacity accessible by several parties for commercial trading in power transaction activities. This paper deals with an application of optimization technique for available transfer capability(ATC) calculation and analyzes the results of ATC by considering several constraints. Sequential quadratic programming(SQP) is used to calculate the ATC problem with state-steady security constraints. The proposed method is applied to 10 machines 39 buses model systems to show its effectiveness.

• Proceedings of the KIEE Conference
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• 2004.11b
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• pp.227-229
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• 2004

In a new competitive market environment, it is very important to determines how much power can be transferred through the network. It's known as Available Transfer Capability(ATC). This paper presents a technique to evaluate Reliability Assesment and the Available Transfer Capability of Haenam-Cheju HVDC transmission system using Well-being Method which is based on the probabilistic method. The system Well-being is categorized in terms of the system Healthy and Marginal in addition to the conventional Risk index. Haenam-Cheju HVDC system has been studied for the optimal ATC based in well-being categories.

• Proceedings of the KIEE Conference
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• summer
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• pp.183-185
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• 2004

This paper deals with an application of optimization technique for available transfer capability(ATC) calculation. ATC is an important indicator of the usable amount of transmission capacity accessible by several parties for commercial trading. Sequential quadratic programming(SQP) is used to calculate the ATC problem with state-steady security constraints. The proposed method is applied to 10 machines 39 buses model systems. The results are discussed and compared to those obtained by continuation power flow(CPF).

• Journal of Drive and Control
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• v.17 no.4
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• pp.1-7
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• 2020

In orchard or crop-growing environments, pesticides are sprayed using various nozzles to prevent pests and improve productivity. Nozzles currently in use are restricted for use in multi-purpose environments, thus, it is necessary to develop new nozzles. In this study, new two-phase nozzles are proposed to improve the performance of the nozzle (flow rate, spray angle, spray particle size). The performance of the two-phase nozzles are predicted through the CFD analysis and the performance of the nozzles is compared with the experiment. The experimental results showed that the proposed two-phase nozzles are available at relatively low operating pressure condition and are capable of extensive spray particle size control. Thus, the proposed nozzles are expected to be available in various orchard environments.

• IEIE Transactions on Smart Processing and Computing
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• v.3 no.5
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• pp.285-297
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• 2014

This paper presents the results of an investigation into bi-directional communication in spectrum sharing-based cognitive radio (Bi-CR) systems. A Bi-CR system can increase the spectral efficiency significantly by sharing the spectrum and through the bi-directional use of spatial resources for two-way communication. On the other hand, the primary user experiences more interference from the secondary users in a Bi-CR system. Satisfying the interference constraint by simply reducing the transmission power results in performance degradation for secondary users. In addition, secondary users also experience self-interference from echo channels due to full duplexing. These imperfections may weaken the potential benefits of the Bi-CR system. Therefore, a new way to overcome these defects in the Bi-CR system is needed. To address this need, this paper proposes some novel power allocation schemes for the Bi-CR system. This contribution is based on two major analytic environments, i.e., noise-limited and interference-limited environments, for providing useful analysis. This paper first proposes an optimal power allocation (OPA) scheme in a noise-limited environment and then analyzes the achievable sum rates. This OPA scheme has an effect in the noise-limited environment. In addition, a power allocation scheme for the Bi-CR system in an interference-limited environment was also investigated. The numerical results showed that the proposed schemes can achieve the full duplexing gain available from the bi-directional use of spatial resources.

• 제어로봇시스템학회:학술대회논문집
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• 2003.10a
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• pp.1732-1735
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• 2003

In this paper, a DSP-based test apparatus for Control Rod Drive Mechanism (CRDM) that is used in nuclear power plants is described. Using this apparatus, we can test the mechanical and electrical characteristics of CRDM and obtain some information about how to improve the CRDM further and how to design a power controller to actuate the CRDM. Since firing angles can be directly applied to the gate-drive circuits of thyristors in the power controller by using this apparatus, the maximum and minimum values of firing angles within available limits are easily measured. Also step-current inputs help us investigate each coil's response characteristics. Therefore, we can easily find the range of control gains which enables a stable CRDM operation in insertion and withdrawal actions at high speed, mid speed, and low speed. Since this apparatus has a test mode in which an insertion or withdrawal action is divided into several phases so that the current command for each phase is given step by step, we may judge whether the CRDM works as expected or not. We also describe a fault detection capability of the test apparatus for the power controller by using discrete Fourier transform.