• ETRI Journal
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• 제36권4호
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• pp.643-653
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• 2014

To reduce interconnect delay and power consumption while improving chip performance, a three-dimensional integrated circuit (3D IC) has been developed with die-stacking and through-silicon via (TSV) techniques. The power supply problem is one of the essential challenges in 3D IC design because IR-drop caused by insufficient supply voltage in a 3D chip reduces the chip performance. In particular, power bumps and TSVs are placed to minimize IR-drop in a 3D power delivery network. In this paper, we propose a design methodology for 3D power delivery networks to minimize the number of power bumps and TSVs with optimum mesh structure and distribute voltage variation more uniformly by shifting the locations of power bumps and TSVs while satisfying IR-drop constraint. Simulation results show that our method can reduce the voltage variation by 29.7% on average while reducing the number of power bumps and TSVs by 76.2% and 15.4%, respectively.

• 마이크로전자및패키징학회지
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• 제19권3호
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• pp.9-14
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• 2012

전자 소자의 기술이 발달함에 따라 전력은 증가하고, 전압은 낮아지고, 입출력 범프 수가 증가하는 반면, 범프 피치는 크게 줄어들지 못하기 때문에 전력전달과 분배 문제는 점점 심각해지고 있다. 그동안 전력전달 문제를 해결하기 위해선 대부분 회로나 아키텍처 차원에서 에너지를 적게 소모하는 방법을 주로 연구해 왔으나, 최근 회로분야와 동시에 새로운 공정설계를 통해서 전력전달 및 분배를 높이고 발열 문제도 처리하는 interconnect 공정 기술이 중요시 되고 있다.

• 한국건설관리학회논문집
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• 제8권1호
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• pp.66-77
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• 2007

2001년 4월 정부의 전력산업 구조개편으로 한국전력공사는 한국수력 원자력과 5개 화력발전사로 분할되었다. 이후 공기업 민영화를 위한 각 발전회사들 간의 경쟁체제에 따라 적극적인 수익창출을 위하여 다양한 발주방식 도입, 적용하고 있다. 하지만, 화력발전소 건설사업은 발주자의 사업목표나 프로젝트의 특성을 제대로 반영하지 못한 채 발주방식을 선정함으로써 프로젝트 참여자들을 만족시키지 못하고 있는 실정이다. 본 연구는 화력발전소 건설사업에서의 발주방식을 선정하기 위해서 고려해야 할 영향요인들을 조사하고 설문 및 면담조사를 통하여 적정한 발주방식의 선정기준을 개발함으로써 발주자의 사업목표에 맞는 발주방식을 선정할 수 있는 모형을 구축하는 것을 목적으로 한다. 향후 본 연구에서 제안한 발주방식 선정모형을 활용하면 주관적이고 경험적인 판단에 의존하여 발주방식을 결정했던 기존의 관행을 벗어나 발주자의 사업목표, 발주자의 특성 및 요구조건, 건설사업의 특성 등을 효과적으로 반영하여 화력발전소 건설사업의 적정한 발주방식을 선정할 수 있을 것으로 기대된다.

• 전기전자학회논문지
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• 제16권2호
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• pp.102-108
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• 2012

3D-IC는 2D-IC와 비교하여 전력 공급 네트워크 설계 시에 더 큰 공급 전류와 더 많은 전력 공급 경로들 때문에 몇 가지 문제점을 가지고 있다. 전력 공급 네트워크는 전력 범프와 전력 TSV로 구성되고, 각 노드의 전압 강하는 전력 범프와 전력 TSV의 개수와 위치에 따라 다양한 값을 가지게 된다. 그래서 칩이 정상적으로 동작하기 위해서는 전압 강하 조건을 만족시키면서 전력 범프와 전력 TSV를 최적화하는 것이 중요하다. 본 논문에서는 3D-IC 전력 공급 네트워크에서 최적의 전력 메시 구조를 통한 전력 범프와 전력 TSV 최적화를 제안한다.

• Journal of Communications and Networks
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• 제18권3호
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• pp.375-386
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• 2016

Most existing studies on broadcast services in orthogonal frequency division multiplexing (OFDM) systems have focused on how to allocate the transmission power to the subcarriers. However, because a broadcasting system must guarantee quality of service to all users, the performance of the broadcast service dominantly depends on the channel state of the user who has the lowest received signal-to-noise ratio among users. To reduce the effect of the worst user on the system performance, we propose a joint delivery scheme of unicast and broadcast transmissions in OFDM systems with broadcast and unicast best-effort users. In the proposed joint delivery scheme, the BS delivers the broadcast information using both the broadcast and unicast subcarriers at the same time in order to improve the performance of the broadcast service. The object of the proposed scheme is to minimize the outage probability of the broadcast service while maximizing the sum-rate of best-effort users. For the proposed joint delivery scheme, we develop an adaptive power and subcarrier allocation algorithm under the constraint of total transmission power. This paper shows that the optimal power allocation over each subcarrier in the proposed scheme has a multi-level water filling form. Because the power allocation and the subcarrier assignment problems should be jointly solved, we develop an iterative algorithm to find the optimal solution. Numerical results show that the proposed joint delivery scheme with adaptive power and subcarrier allocation outperforms the conventional scheme in terms of the outage probability of the broadcast service and the sum-rate of best-effort users.

• IEIE Transactions on Smart Processing and Computing
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• 제5권5호
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• pp.349-357
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• 2016

The era of the Internet of Things (IoT) is upon us. In this era, minimizing power consumption becomes a primary concern for system-on-chip designers. While traditional power minimization and dynamic power management (DPM) techniques have been heavily explored to improve the power efficiency of devices inside very large-scale integration (VLSI) platforms, there is one critical factor that is often overlooked, which is the power conversion efficiency of a power delivery network (PDN). This paper is a tutorial that focuses on the power conversion efficiency of the PDN, and introduces novel methods to improve it. Circuit-, architecture-, and system-level approaches are presented to optimize PDN designs, while case studies for three different VSLI platforms validate the efficacy of the introduced approaches.

• 한국임상수의학회지
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• 제20권3호
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• pp.364-368
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• 2003

Cytogenetic and hematological analysis was performed in peripheral blood from the cattle associated with abnormal delivery around nuclear power plant area. The frequency of micronuclei (MN) in peripheral blood lymphocytes from cattle was used as a biomarker of radiobiological effects resulting from exposure to environmental radiation. An estimated dose of radiation was calculated by best fitting linear-quadratic model based on the radiation-induced MN data over the range from 0 Gy to 4 Gy from the bovine lymphocytes with in vitro irradiation. MN rates in live malformed calf, dams of malformed calves and other cattle living in the same barn from the regions around nuclear power plant, and cattle in control area were 9/1000, 10.8/1000, 13.3/1000 and 10.0/1000, respectively. There were no significant differences in MN frequencies and hematological values between the cattle associated with abnormal delivery around nuclear power plant area and those of control area. This study indicates that the congenital abnormalities near nuclear power plant seemed to be caused by other aetiology.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2011년도 춘계학술대회 논문집
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• pp.1263-1264
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• 2011

• Journal of Power Electronics
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• 제18권1호
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• pp.234-250
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• 2018

This paper presents a new load sharing control for use between paralleled three-phase inverters in an islanded microgrid based on the online line impedance estimation by the use of a Kalman filter. In this study, the mismatch of power sharing when the line impedance changes due to temperature, frequency, significant differences in line parameters and the requirements of the Plug-and-Play mode for inverters connected to a microgrid has been solved. In addition, this paper also presents a new droop control method working with the line impedance that is different from the traditional droop algorithm when the line impedance is assumed to be pure resistance or pure inductance. In this paper, the line impedance estimation for parallel inverters uses the minimum square method combined with a Kalman filter. In addition, the secondary control loops are designed to restore the voltage amplitude and frequency of a microgrid by using a combined nominal value SOGI-PLL with a generalized integral block and phase lock loop to monitor the exact voltage magnitude and frequency phase at the PCC. A control model has been simulated in Matlab/Simulink with three voltage source inverters connected in parallel for different ratios of power sharing. The simulation results demonstrate the accuracy of the proposed control method.

• 드라이브 ㆍ 컨트롤
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• 제21권1호
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• pp.38-45
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• 2024

The power delivery is crucial to designing agricultural machinery. Therefore, the tractor-mounted potato harvester was used in this study to conduct the field experiment and analyze the power delivery for each step. This study was focused on an analysis of power delivery from the engine to the hydraulic components for the tractor-mounted harvester during potato harvesting. Finally, the simulation model of a self-propelled potato harvester was developed and validated using the experimental dataset of the tractor-mounted potato harvester. The power delivery analysis showed that approximately 90.22% of the engine power was used as traction power to drive the tractor-mounted harvester, and only 5.10% of the engine power was used for the entire hydraulic system of the tractor and operated the harvester. The statistical analysis of the simulation and experimental results showed that the coefficient of determinations (R²) ranged from 0.80 to 0.96, which indicates that the simulation model was performed with an accuracy of over 80%. The regression models were correlated linearly with the simulation and experimental results. Therefore, we believe that this study could contribute to the design methodology and performance test procedure of agricultural machinery. This basic study would be helpful in the design of a self-propelled potato harvester.