• 대한전기학회:학술대회논문집
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• 대한전기학회 1999년도 추계학술대회 논문집 학회본부 A
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• pp.206-209
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• 1999

This paper presents an improved method of calculating the penalty factors for economic load dispatch based on B-coefficient and AC load flow and their performance comparison. The algorithm for calculating B-coefficients by Meyer is improved and its performance is compared with that of AC load flow. The B-coefficient method is superior to the load flow method in its simplicity and computation speed. However accuracy of the B-coefficient method is not satisfactory when it is applied to the ill-conditioned systems where generators produce excessive reactive power.

• Journal of the Optical Society of Korea
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• 제11권3호
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• pp.93-96
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• 2007

We demonstrate a 240 km reach DWDM-PON at 8-Gb/s capacity based on wavelength-locked Fabry-Perot laser diodes and a bidirectional EDFA. We achieve a packet-error-free transmission in both the 64 upstream and 64 downstream channels, guaranteeing a 125 Mb/s symmetric data rate per user. There is no noticeable dispersion penalty. The power penalty due to the crosstalk induced by the DWDM transmission and detuning between AWGs is less than 1.2 dB, when the detuning is within ${\pm}0.12 nm$.

• 전기전자학회논문지
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• 제25권3호
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• pp.479-484
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• 2021

본 논문은 SIMT구조의 GPGPU에서 적은 core수로 고성능을 달성하기 위한 구조를 제안하고 설계하였다. 모바일기기에 적용하기 위한 GPGPU는 소모전력대비 성능을 높이기 위한 구조가 필수적이다. 소모전력을 줄이기 위해서 core수가 줄어든 대신 성능을 높이기 위해 thread를 관리하기 위한 warp scheduler의 size를 4로 하여 일반적인 GPGPU의 32 보다 크게 줄였다. Warp size를 적게 되면 pipeline의 idle cycle수를 줄일 수 있고 cache 메모리 접근시 miss penalty를 줄이기 위한 memory latency 적용이 효율적이다. 설계된 GPGPU는 부동소수점 연산을 포함하는 테스트 프로그램으로 연산 성능을 측정하고 28nm CMOS공정으로 소비전력을 측정하여 전력당 성능지수로 104.5GFlops/Watt를 얻었다. 본 논문의 결과는 Nvidia의 Tegra K1과 비교하였을 때 약 4배 우수한 전력당 성능지수를 보였다.

• Journal of Electrical Engineering and Technology
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• 제3권1호
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• pp.130-134
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• 2008

The increasing size of very large scale integration (VLSI) circuits, high transistor density, and popularity of low-power circuit and system design are making the minimization of power dissipation an important issue in VLSI design. Test Power dissipation is exceedingly high in scan based environments wherein scan chain transitions during the shift of test data further reflect into significant levels of circuit switching unnecessarily. Scan chain or cell modification lead to reduced dissipations of power. The ETC algorithm of previous work has weak points. Taking all of this into account, we therefore propose a new algorithm. Its name is RE_ETC. The proposed modifications in the scan chain consist of Exclusive-OR gate insertion and scan cell reordering, leading to significant power reductions with absolutely no area or performance penalty whatsoever. Experimental results confirm the considerable reductions in scan chain transitions. We show that modified scan cell has the improvement of test efficiency and power dissipations.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2005년도 제36회 하계학술대회 논문집 A
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• pp.480-482
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• 2005

In this paper, utilization of load duration curves is presented for analyzing the effect of load power factor and determining the value of load power factor effectively. In addition, the power factor sensitivity of generation cost and integrated costs including voltage variation penalty cost are used for determining the value of the load power factor from the point of view of voltage regulation and economic investment. It is shown through the application to the KEPCO power system that the load power factor can be enhanced effectively and appropriately using the load duration curve.

• International Journal of Railway
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• 제2권2호
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• pp.70-79
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• 2009

An optimal driving strategy of a train in a long journey on a nonsteep track has four phases: an initial power phase, a long hold speed phase, a coast phase and a final brake phase. The majority of the journey is speed holding. On a track with steep gradients, it becomes necessary to vary the strategy around steep sections of track because it is not possible to hold a constant steep on steep track. Instead we must interrupt the speed hold phase with a power phase. The aim of this paper is to show that there is a unique power phase that satisfies the necessary conditions for an optimal journey. The problem is developed and solved for various cases, from a simple single steep gradient to a complicated multiple steep gradient section. For each case, we construct a set of new conditions for optimality of the power phase that minimises the energy used during the power phase subject to a weighted time penalty. We then use the new necessary conditions to develop a calculate scheme for finding an optimal power phase for a steep incline. We also present an example to confirm the uniqueness of an optimal power phase.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2005년도 추계학술대회 논문집 전력기술부문
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• pp.159-161
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• 2005

Transmission congestion is one of the key factors to local market power in competitive electricity markets. Financial transmission rights provide the financial protection to their holders by paying back the congestion cost. However, the market participants who have market power can exacerbate their market power. Due to the exacerbated market power, this paper analyzes the mitigation of local market power using Contingent transmission rights on the market price. Contingent transmission rights provide not only the financial protection but also regulative penalty. The proposed methodology was demonstrated with the Optimal Power Flow(OPF).

• 한국전자파학회논문지
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• 제12권7호
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• pp.1157-1166
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• 2001

본 논문에서는 분산 천이 광섬유를 전송로로 채택한 10 Gbps, 20 Gbps, 40 Gbps 전송 시스템에서의 전력 대칭 MSSI(mid-span spectral inversion)에 의한 보상 정도를 변조된 광 펄스의 다양한 첩 파라미터에 따라 분석하였다. 우선 각각의 전송 속도에서 입력 전력 변화에 따른 수신단에서의 EOP(eye-opening penalty)를 계산하여 수신 성능을 양호하게 유지할 수 있는 최대 입력 전력의 크기를 첩 파라미터에 따라 살펴보았다. 또한 MSSI의 장거리 광대역 WDM 전송 시스템에의 적용 가능성을 확인해 보기 위하여 송신단부터 광 위상 공액기(OPC; optical phase conjugator)가지의 첫 번째 광섬유의 분산 계수 D$_{11}$ 변동에 따른 EOP의 고찰을 통해 수신 성능이 양호하게 유지될 수 있는 송신 과장의 범위를 살펴보았다. 본 논문에서 제안된 최적 펌프 전력 조건을 유지하는 MSSI 방법은 이상 분산(anomalous dispersion) 영역에서 변조 과정을 통해 광 펄스에 인가된 초기 첩이 up-chirp 인 경우보다 down-chirp인 경우에서 더욱 효과적임을 확인할 수 있었고. 장거리 WDM 전송에서 비트율에 따라 3.5 dBm 이상의 비교적 높은 전력으로 수~수 십 nm 이상의 광대역 전송이 가능하다는 것을 확인할 수 있었다.다.

• Journal of Electrical Engineering and Technology
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• 제11권1호
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• pp.76-85
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• 2016

This paper presents a method of decision on where bus splitting is needed to reduce fault current level of power systems and to satisfy the fault current constraints. The method employs a modified fault current constrained optimal power flow (FCC-OPF) with X variables for the candidate locations of splitting and for decision making on whether to split or not, it adopts soft-discretization by augmenting inversed U-shaped penalty terms. Also, this paper discusses the procedure on the adequate selection of bus splitting locations based on the results of the modified FCC-OPF, to reduce the total number of the actions taken.

• Journal of information and communication convergence engineering
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• 제7권3호
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• pp.372-376
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• 2009

In this paper, new and simple optical transmission link with fixed dispersion management (DM) scheme, i.e., pre(post) compensation and residual dispersion per span (RDPS) are fixed to net residual dispersion (NRD) = 0 ps/nm, and optical phase conjugator (OPC) having optimal position depending on launch power in WDM transmission system is proposed. Also, effective launch power range of WDM channels resulting 1 dB eye opening penalty (EOP) is induced as a function of OPC position. First, it is confirmed that, for applying DM into WDM transmission link fixed pre(post)compensation and RDPS, which are independence on exact system parameters except launch power, sufficiently are used in WDM links, but OPC with optimal position is needed for effective compensating impairments of WDM channels. And, it is confirmed that effective launch power is broader in case of RDPS = 100 ps/nm than in RDPS = 50 ps/nm. But, it is shown that the best OPC position offset is -0.6 km from a point of view of power window, which is defined as difference between maximum and minimum effective launch power.