• Journal of the Korea Society of Computer and Information
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• v.26 no.8
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• pp.1-11
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• 2021

This paper proposes a novel mechanism called Event-driven Uncore Frequency Scaler (eUFS) to improve the energy efficiency of the HPC systems. UFS exploits the hardware events such as LAPI (Last-level Cache Accesses Per Instructions) and CPI (Clock Cycles Per Instruction) to dynamically adjusts the uncore frequency. Hardware events are collected at a reference time period, and the target uncore frequency is determined using the collected event and the previous uncore frequency. Experiments with the NPB benchmarks demonstrate that the eUFS reduces the energy consumption by 6% on average for class C and D NPB benchmarks while it only increases the execution time by 2% on average.

• Proceedings of the Korean Magnestics Society Conference
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• 2015.05a
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• pp.118-118
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• 2015

• Proceedings of the Korean Information Science Society Conference
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• 2006.10d
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• pp.223-227
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• 2006

인터넷의 발전에 따라 다자간 그룹 통신 환경이 주목을 받게 되었고 이를 위해 다대다 멀티캐스트를 이용한 통신 기법들이 제안되었다. 이들 중 GAM (Group Aided Multicast) 은 다대다 멀티캐스트의 신뢰적 전달을 보장하기 위해 트리 기반의 손실 복구 기법을 제안하고, 제어 트리 관리 비용과 손실 복구 효율성간의 접점을 찾기 위해 그룹 개념을 도입하고 그룹의 대표로서 코어 노드를 정의한다. 코어 노드는 네트워크 상의 특정 지점에 미리 설치된 전용 노드로서 그룹 내의 손실 복구와 그룹 간의 손실 제어를 담당한다. 그러나 이러한 전용 코어 노드의 도입은 프로토콜의 가용성을 제한하고 코어 노드의 설치 부담을 가지게 된다. 따라서 본 논문에서는 별도의 코어 노드의 설치 없이 프로토콜이 동작할 수 있도록 세션 참가자 중에서 코어 노드를 동적으로 선택하고, 로컬 그룹 노드 중에서 제어 트리의 효율성을 최대한 보장하는 노드의 위치를 결정하는 기법을 제안한다.

• Proceedings of the Korean Magnestics Society Conference
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• 2016.05a
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• pp.86-86
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• 2016

• Proceedings of the IEEK Conference
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• 2002.06e
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• pp.39-42
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• 2002

A new adaptive PRML architecture, considered not only DVD-ROM but also DVD-Multi including DVD-RAM as well, is presented to demonstrate its superiority over the conventional analog channel in a DVD system. For this new architecture, channel adaptation algorithm using gain controlled type of FIR filter, and asymmetry compensation algorithm using expected level adaptation of viterbi decoder are presented. In addition, a method of modelling the disk tilt and asymmetrical read-back signal are discussed.

• Proceedings of the Korea Concrete Institute Conference
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• 2005.05a
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• pp.123-126
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• 2005

The purpose of this study is to evaluate a effect of core reinforcement ratio to PC wide girder-column joint. Three half scale subassemblies were representing a portion of a protype structure were design, constructed, and tested to failure. From the test result, girder-column width ratio play an important role in the improvement of strength and ductility.

• Journal of the Korea Society of Computer and Information
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• v.25 no.11
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• pp.75-82
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• 2020

In this paper, we propose a training method to efficiently create prototypes using 'core mechanical diagram' to make game design easier and 'BluePrint', a visual scripting tool of Unreal that enables relatively easy functionality without programming knowledge. With the development of game engines, game development is becoming faster and easier, and using this, non-programmers without knowledge of game development are clearly showing a tendency to participate in game development. However, existing game development methodologies and game implementation methods require complex design processes and specialized knowledge. In order to make it easier for non-programming experts to develop games, they will simplify the complexity of existing game development methodologies, and propose educational methods that can focus on and implement the essence of game design based on cases where non-programmers have implemented prototypes themselves.

• Journal of the Korean Magnetics Society
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• v.25 no.1
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• pp.10-15
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• 2015

The model for the magneto-impedance of composite wires composed of highly conductive nonmagnetic metal core and soft magnetic shell was derived based on the Maxwell's equations. The Cu($100{\mu}m$ diameter)/$Ni_{80}Fe_{20}$($15{\mu}m$ thickness) core/shell composite wire was fabricated by electrodeposition. The impedance spectra for the $Cu/Ni_{80}Fe_{20}$ core/shell composite wire were measured in the frequency range of 10 kHz~10 MHz under longitudinal dc magnetic field in 0 Oe~200 Oe. The spectra of complex permeability in circumferential direction were extracted from the impedance spectra by using the derived model. The extracted spectra of complex permeability showed relaxation-type dispersion which is well curve-fitted with Debye equation with single relaxation frequency. By analyzing the magnetic field dependence of the complex permeability spectra, it has been verified that the composite wire has magnetic anisotropy in longitudinal direction and the origin of the single relaxation process is the magnetization rotation in circumferential direction.

• Journal of the Korean Magnetics Society
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• v.25 no.4
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• pp.129-137
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• 2015

The Cu(radius ra = $95{\mu}m$)/$Ni_{80}Fe_{20}$(outer radius $r_b$ = $120{\mu}m$) core/shell composite wire is fabricated by electrodeposition. The two diagonal components of impedance tensor for the Cu/$Ni_{80}Fe_{20}$ core/shell composite wire in cylindrical coordinates, $Z_{zz}$ and $Z_{{\theta}{\theta}}$, are measured as a function of frequency in 10 kHz~10 MHz and external static magnetic field in 0 Oe~200 Oe. The equations expressing the diagonal $Z_{zz}$ and $Z_{{\theta}{\theta}}$ in terms of diagonal components of complex permeability tensor, ${\mu}^*_{zz}$ and ${\mu}^*_{{\theta}{\theta}}$, are derived from Maxwell's equations. The real and imaginary parts of ${\mu}^*_{zz}$(f) and ${\mu}^*_{{\theta}{\theta}}$(f) spectra are extracted from the measured $Z_{zz}$(f) and $Z_{{\theta}{\theta}}$(f) spectra, respectively. It is presened that the extraction of ${\mu}^*_{zz}$(f) and ${\mu}^*_{{\theta}{\theta}}$(f) spectra from the diagonal impedance spectra can be a versatile tool to investigate dymanic magnetization process in the core/shell composite wire.

• Journal of Sensor Science and Technology
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• v.12 no.2
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• pp.72-78
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• 2003

To observe the effect of excitation coil pitch on the micro fluxgate magnetic sensor, two sensors are fabricated using multi layer board process and the pitch distance of excitation coil are $260\;{\mu}m$ and $520\;{\mu}m$, respectively. The fluxgate sensor consists of five PCB stack layers including one layer of magnetic core and four layers of excitation and pick-up coils. The center layer as magnetic core is made of a Co-based amorphous magnetic ribbon with extremely high DC permeability of ${\sim}100,000$ and has a rectangular-ring shape to minimize the magnetic flux leakage. Four outer layers as excitation and pick-up coils have a planar solenoid structure and are made of copper foil. In case of the fluxgate sensor having the excitation coil pitch of $260\;{\mu}m$, excellent linear response over the range of $-100\;{\mu}T$ to $+100\;{\mu}T$ is obtained with sensitivity of 780 V/T at excitation sine wave of $3V_{p_p}$ and 360 kHz. The chip size of the fabricated sensing element is $7.3\;{\times}\;5.7\;mm^2$. The very low power consumption of ${\sim}8\;mW$ is measured. This magnetic sensor is very useful for various applications such as: portable navigation systems, telematics, VR game and so on.