• JSTS:Journal of Semiconductor Technology and Science
• /
• 제15권6호
• /
• pp.695-702
• /
• 2015

A 1-V 1.6-GS/s 5.58-ENOB flash ADC with a high-speed time-domain comparator is proposed. The proposed time-domain comparator, which consumes low power, improves the comparison capability in high-speed operations and results in the removal of preamplifiers from the first-stage of the flash ADC. The time interpolation with two factors, implemented using the proposed time-domain comparator array and SR latch array, reduces the area and power consumption. The proposed flash ADC has been implemented using a 65-nm 1-poly 8-metal CMOS process with a 1-V supply voltage. The measured DNL and INL are 0.28 and 0.41 LSB, respectively. The SNDR is measured to be 35.37 dB at the Nyquist frequency. The FoM and chip area of the flash ADC are 0.38 pJ/c-s and $620{\times}340{\mu}m^2$, respectively.

• Nuclear Engineering and Technology
• /
• 제52권11호
• /
• pp.2667-2677
• /
• 2020

A domain decomposition (DD) scheme for GPU-based Monte Carlo (MC) calculation which is essential for whole-core depletion is introduced within the framework of the modified history-based tracking algorithm. Since GPU-offloaded MC calculations suffer from limited memory capacity, employing DDMC is inevitable for the simulation of depleted cores which require large storage to save hundreds of newly generated isotopes. First, an automated domain decomposition algorithm named wheel clustering is devised such that each subdomain contains nearly the same number of fuel assemblies. Second, an innerouter iteration algorithm allowing overlapped computation and communication is introduced which enables boundary neutron transactions during the tracking of interior neutrons. Third, a bank update scheme which is to include the boundary sources in a way to be adequate to the peculiar data structures of the GPU-based neutron tracking algorithm is presented. The verification and demonstration of the DDMC method are done for 3D full-core problems: APR1400 fresh core and a mock-up depleted core. It is confirmed that the DDMC method performs comparably with the standard MC method, and that the domain decomposition scheme is essential to carry out full 3D MC depletion calculations with limited GPU memory capacities.

• International Journal of Naval Architecture and Ocean Engineering
• /
• 제13권1호
• /
• pp.50-56
• /
• 2021

An accurate evaluation of three-dimensional (3D) Time-Domain Green Function (TDGF) in infinite water depth is essential for ship's hydrodynamic analysis. Various numerical algorithms based on the TDGF properties are considered, including the ascending series expansion at small time parameter, the asymptotic expansion at large time parameter and the Taylor series expansion combines with ordinary differential equation for the time domain analysis. An efficient method (referred as "Present Method") for a better accuracy evaluation of TDGF has been proposed. The numerical results generated from precise integration method and analytical solution of Shan et al. (2019) revealed that the "Present method" provides a better solution in the computational domain. The comparison of the heave hydrodynamic coefficients in solving the radiation problem of a hemisphere at zero speed between the "Present method" and the analytical solutions proposed by Hulme (1982) showed that the difference of result is small, less than 3%.

• 한국전산구조공학회논문집
• /
• 제12권4호
• /
• pp.537-549
• /
• 1999

선형탄성 파괴해석은 균열을 갖는 변형률 경화재료의 파괴거동을 예측하는데 불충분하기 때문에 최근에는 균열 선단 부에서 대규모 소성 역을 갖는 균열 체에 적용할 수 있는 많은 파괴역학개념이 제안되고 있다. 따라서, 본 연구에서는 대규모항복 조건하의 연성파괴를 보이는 평판을 정확하게 해석할 수 있는 새로운 유한요소모델을 제시하고자 한다. 균열 선단 부의 응력 장을 정의하는데 가장 지배적인 파괴매개변수인 J-적분 값과 소성 역의 크기 및 형상을 J-적분법과 등가영역적분법을 통해 파괴거동을 설명할 수 있도록 증분소성이론에 기초를 둔 p-version 유한요소해석이 채택되었다. 제안된 유한요소모델에 의한 수치해석결과는 이론 해와 h-version 유한요소해석과 비교되었다.

• 한국진공학회:학술대회논문집
• /
• 한국진공학회 2010년도 제39회 하계학술대회 초록집
• /
• pp.276-276
• /
• 2010

Large-area micropatterned array of Co/Ni bilayer anti-dots was fabricated using photolithography and wet etching process. The surface morphology as well as the surface topography was checked by scanning electron microscopy and atomic force microscopy, whereas the magnetic properties were studied by magneto-optical Kerr effect (MOKE) and magnetic force microscopy (MFM). Systematic studies of the magnetic-reversal mechanism, the in-plane anisotropy and the switching field properties were carried out. To get a comprehensive knowledge about the domain configuration, we also employed OOMMF simulations. It was found from the MOKE measurements that a combined effect of configurational and the magneto-crystalline anisotropy simultaneously works in such micropatterned bilayer structures. In addition, the inclusion of holes in the uniform magnetic film drastically affected the switching field. The MFM images show well-defined domain structures which are periodic in nature. The micromagnetic simulations indicate that the magnetization reversal of such a structure proceeds by formation and annihilation of domain walls, which were equally manifested by the field-dependent MFM images. The observed changes in the magnetic properties are strongly related to both the patterning that hinders the domain-wall motion and to the magneto-anisotropic bilayered structure.

• Journal of Magnetics
• /
• 제14권2호
• /
• pp.53-61
• /
• 2009

Herein, different concepts for domain wall propagation based on currents and fields that could potentially be used in magnetic data storage devices based on domains and domain walls are reviewed. By direct imaging, we show that vortex and transverse walls can be displaced using currents due to the spin transfer torque effect. For the case of field-induced wall motion, particular attention is paid to the influence of localized fields and local heating on the depinning and propagation of domain walls. Using an Au nanowire adjacent to a permalloy structure with a domain wall, the depinning field of the wall, when current pulses are injected into the Au nanowire, was studied. The current pulse drastically modified the depinning field, which depended on the interplay between the externally applied field direction and polarity of the current, leading subsequently to an Oersted field and heating of the permalloy at the interface with the Au wire. Placing the domain wall at various distances from the Au wire and studying different wall propagation directions, the range of Joule heating and Oersted field was determined; both effects could be separated. Approaches beyond conventional field- and current-induced wall displacement are briefly discussed.

• Asian-Australasian Journal of Animal Sciences
• /
• 제25권5호
• /
• pp.606-612
• /
• 2012

Insulin-like growth factor-binding protein-5 (IGFBP-5) is one of the six members of IGFBP family, important for cell growth, apoptosis and other IGF-stimulated signaling pathways. In order to explore the significance of IGFBP-5 in cells of the Inner Mongolian Cashmere goat (Capra hircus), IGFBP-5 gene complementary DNA (cDNA) was amplified by reverse transcription polymerase chain reaction (RT-PCR) from the animal's fetal fibroblasts and tissue-specific expression analysis was performed by semi-quantitative RT-PCR. The gene is 816 base pairs (bp) in length and includes the complete open reading frame, encoding 271 amino acids (GenBank accession number JF720883). The full cDNA nucleotide sequence has a 99% identity with sheep, 98% with cattle and 95% with human. The amino acids sequence shares identity with 99%, 99% and 99%, respectively. The bioinformatics analysis showed that IGFBP-5 has an insulin growth factor-binding protein homologues (IB) domain and a thyroglobulin type-1 (TY) domain, four protein kinase C phosphorylation sites, five casein kinase II phosphorylation sites, three prenyl group binding sites (CaaX box). The IGFBP-5 gene was expressed in all the tested tissues including testis, brain, liver, lung, mammary gland, spleen, and kidney, suggesting that IGFBP-5 plays an important role in goat cells.

• 전기전자학회논문지
• /
• 제17권4호
• /
• pp.525-530
• /
• 2013

워크플로우의 표준인 BPEL은 프로그래밍 언어에 대한 이해도가 낮은 도메인 전문가도 손쉽게 비즈니스 흐름을 작성할 수 있다. 하지만 특정 도메인에서는 BPEL 문법에 없는 새로운 기능이 요구된다. BPEL 엔진이 새로운 기능을 처리하기 위해서는 새로운 BPEL 엔진을 개발하거나 기존의 BPEL 엔진에 기능을 추가해야 하는데 이는 비용이 많이 필요하다. 본 논문에서는 XML 스키마를 확장하여 XAS4B 문서를 제안하고 관점지향 프로그래밍 기법을 이용하여 BPEL 엔진에 새로운 기능을 추가하는 방법을 보인다. 관점지향 프로그래밍 기법은 직조를 이용하여 핵심관심사의 수정없이 횡단관심사를 추가할 수 있다. 본 연구에서는 기존의 BPEL 엔진으로 B2J (BPEL to JAVA)를 사용하는데 이 엔진은 BPEL 문서를 JAVA 프로그램으로 변환하고 이를 실행한다. 본 시스템은 B2J 엔진이 생성한 JAVA 프로그램을 핵심관심사로 새로운 기능을 처리하는 프로그램을 횡단관심사로 두 프로그램을 직조하여 BPEL 흐름에 새로운 기능의 흐름을 추가한다. 제안하는 방법은 BPEL의 새로운 기능을 추상적으로 제공하여 한 번 개발된 새로운 기능을 도메인 전문가가 재사용하기 손쉽다.

• Journal of Magnetics
• /
• 제11권2호
• /
• pp.61-65
• /
• 2006

The physical origin of complex dynamic domain configuration in nonequilibrium magnetic systems with mesoscopic length scales has been studied. An increasing complexity in the spatial feature of the evolution is found to accompany the increasing reversal speed, when a ferromagnetic element is driven by progressively faster switching fields applied antiparallel to the initial magnetization direction. As reversal rates approach the characteristic precession frequencies of spin fluctuations, the thermal energy can boost the magnetization into local configurations which are completely different from those experienced during quasistatic reversal. The sensitive dependence of the spatial pattern on switching speed can be understood in terms of a dynamic exchange interaction of thermally excited spins; the coherent modulation of the spins is strongly dependent on the rise time of switching pulses.

• 제어로봇시스템학회논문지
• /
• 제12권4호
• /
• pp.380-388
• /
• 2006

A noisy behavior of the time domain passivity controller during the period of low velocity is analyzed. Main reasons of the noisy behavior are investigated through a simulation with a one-DOF (Degree of Freedom) haptic interface model. It is shown that the PO/PC is ineffective in dissipating the produced energy when the sign of the velocity, which is numerically calculated from the measured position, is suddenly changed, and when this velocity is zero. These cases happen during the period of low velocity due to the limited resolution of the position sensor. New methods, ignoring the produced energy from the velocity sign change, and holding the control force while the velocity is zero, are proposed for removing the noisy behavior. The feasibility of the developed methods is proved with both a simulation and a real experiment.