• Journal of KIISE:Computer Systems and Theory
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• v.26 no.11
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• pp.1305-1317
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• 1999

NUMA 구조는 원격 메모리에 대한 접근이 불가피한 구조적 특성 때문에 상호 연결망이 성능을 좌우하는 큰 변수가 된다. 기존에 대중적으로 사용되던 버스는 물리적 확장성 및 대역폭에서 대규모 시스템을 구성하는 데 한계를 보인다. 이를 대체하는 고속의 지점간 링크를 사용한 링 구조는 버스가 가지는 확장성 및 대역폭의 한계라는 단점을 개선하였으나, 많은 클러스터가 연결되는 경우에는 전송 지연시간이 증가하는 문제점을 가지고 있다. 본 논문에서는 스누핑 프로토콜이 적용된 링 구조에서 클러스터 개수 증가에 따른 지연시간 증가의 문제점을 보완하기 위해 계층적 링 구조로의 확장을 제안하고, 이 구조에 효과적인 캐쉬 일관성 프로토콜을 설계하였다. 전역 링과 지역 링을 연결하는 브리지는 캐쉬 프로토콜을 관리하며 이 프로토콜에 의해 지역 링의 부하를 줄일 수 있도록 트랜잭션을 필터링하는 역할도 담당함으로써 시스템의 성능을 향상시킨다. probability-driven 시뮬레이터를 통해 계층적 링 구조가 시스템의 성능 및 링 이용률에 미치는 영향을 알아본다. Abstract Since NUMA architecture has to access remote memory, interconnection network performance determines performance of NUMA architecture. Bus, which has been used as popular interconnection network of NUMA, has a limit to build a large-scale system because of limited physical scalability and bandwidth. Ring interconnection network, composed of high-speed point-to-point link, made up for bus's defects of scalability and bandwidth. But, it also has problem of increasing delay as the number of clusters is increased. In this paper, we propose a hierarchical expansion of snoop-based ring architecture in order to overcome ring's defects of increasing delay. And we also design an efficient cache coherence protocol adopted to this architecture. Bridge, which connects local ring and global ring, maintains cache coherence protocol and does snoop-filtering which reduces local ring and cluster bus utilization. Therefore bridge can improve performance of this system. We analyze effects of hierarchical architecture on the performance of system and utilization of point-to-point links using probability-driven simulator.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.10 no.10
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• pp.2551-2556
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• 2009

The principal operation of a ring laser gyroscope depends on the phase difference for the counter-propagating waves within a closed path. The reflection mirrors mounted on the resonator block form the traveling waves. Thus, the dimension accuracy of resonator block influences the traveling path of beam. In order to maintain the stable optical beam path in the ring resonator, the piezo-driven moveable mirror is adopted for the path length control under the thermal expansion or mechanical strain of resonator block. This paper presents the mathematical description of the elastic behavior of piezo-driven mirror. This description can be applied for the concept design of piezo-driven mirror.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.32 no.3
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• pp.115-120
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• 2022

A brown ring (hereinafter referred to as BR) on the inner surface of a quartz glass crucible used in the manufacturing process of a silicon ingot for semiconductor wafers was studied. BR is 20~30 ㎛ in size and has an asymmetric brown ring shape. The size and distribution of BR were different depending on the crucible location, and the size and distribution of BR were the largest and most abundant in the round part with the highest crucible temperature during Si ingot growth. BR contains cristobalite, which has a higher coefficient of thermal expansion than quartz glass, so it is considered that surface cracks appear. The color development of BR and pin holes are presumed to be due to oxygen vacancies.

• Proceedings of the KIEE Conference
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• 1995.07c
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• pp.1371-1374
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• 1995

It is well known that the degradation of transformer oil conseqently lead to the failure of transformer. This paper discussed the characteristics of the degradation sensor checking transformer oil condition in live line. The degadation sensor is composed of base ring, electrodes and porous ceramic, passed through the transformer oil and checks the transformer oil condition through sensor's leakage current. So it is important to minimize the leakage current of base ring and connection parts. To investigate the leakage current of base ring and connection parts the characteristics of V-T-I and DC 2 KV and other examinations were performed. It is verified that ionized transformer oil caused by the expansion of temperature increases in the leakage current of porous ceramic sensor. It is certification that the leakage current of other parts of porous ceramic is very small(about 2%) compared with the porous ceramic body and it is confirmed that the leakage current in porous ceramic is changed sensitively according to the new oil(NO) and and the degradation oil(DO).

• Journal of Advanced Marine Engineering and Technology
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• v.32 no.8
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• pp.1257-1262
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• 2008

A long-distance remote sensing of temperature and current based on a fiber Bragg grating (FBG) is proposed and demonstrated. The thermal expanding effect of the epoxy and the Er-doped fiber ring laser (EFRL) are applied to the sensor system to enhance the temperature and current sensitivity. An EFRL with a 5 km-single-mode fiber and a FBG shows a high extinction ratio of more than 60 dB and a low power fluctuation of less than 1 dB. The metal wires are used to supply the current to the sensors. When the NOA65 puts on the FBG as a thermal expanding material, the temperature and current sensitivity of the lasing wavelength shift are about $30\;pm/^{\circ}C$ and 3pm/mA, respectively. The proposed sensing scheme is useful for measurement of current or temperature at a distant object of more than several km.

• Proceedings of the KIEE Conference
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• 1996.07c
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• pp.1765-1768
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• 1996

It is well known that the degradation transformer oil is mainly effected to the failure of transformer. In this paper it is discussed the characteristics of the degradation sensor checking transformer oil condition in live line. The degadation sensor composed with base ring, electrodes and porous ceramic passed through the transformer oil and checked the transformer oil condition with sensor's leakage current. It is important to minimize the leakage current of base ring and connection parts. To investigate the leakage current of base ring and connection parts it is examined the characteristics of V-T-I and DC 2 KV and other examinations. It is verified that ionized transformer caused by the expansion of oil temperature increase in the leakage current of porous ceramic sensor. It is certificated that the leakage current of other parts of porous ceramic is very small (about 2 %) than the porous ceramic and it is confirmed that the leakage current in porous ceramic is changed sensitively according to the new oil(NO) and and the degradation oil(DO).

• Proceedings of the KIEE Conference
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• 1998.07a
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• pp.107-109
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• 1998

This paper presents mechanical analysis of gas turbine generator (113MVA, $3{\phi}$, 2P, 0.9PF, F class, 3600rpm, 60Hz, 13.8kV, 4.72kA, Air-Cooling) field coil deformation. Rotor end coil deformation is only appeared on turbine end but collector end coil is normal. Expansion direction of end coil is tangential not axial. Deformation appears more severe at top turn. Retaining ling is expanded by centrifugal force of coil and itself. In case friction coefficient between coil top surface and retaining ring insulation inner surface is small, coil end length ${\ell}$ does not change. However, in case friction coefficient big condition, coil end is expanded ${\Delta}{\ell}$ due to start and stop. Deformation is assumed about 30mm by watching photograph inner surface of retaining ring is coated by Teflon at manufacturing condition. Usually Teflon coating insulation surface is small friction coefficient. It's value 0.08${\sim}$0.15. However it's value exceeds more than 0.297. Since top turn deformation appears. The distortion and subsequent failure have occurred because of the lack of a sufficient slip-plane between the top field coil conductors and the inside surface of the retaining ring insulation on the turbine end of the field-winding.

• The Bulletin of The Korean Astronomical Society
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• v.40 no.1
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• pp.59.1-59.1
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• 2015

We present hydrodynamic simulations of gas clouds that inflowing from the disk to a few hundred parsec region of the Milky Way. Realistic Galactic structures are included in our simulations by thousands of multipole expansions that describe 6.4 million stellar particles of a self-consistent Galaxy simulation (Baba, Saitoh & Wada, in prep.). We find that a hybrid multipole expansion model with two different basis sets and a thick disk correction well reproduces the overall structures of the Milky Way. We find that the nuclear ring evolves into 240 pc at T~1500 Myr, regardless of the initial size. For most of simulation runs, gas inflow rate to the nuclear region is equilibrated as ~0.02 Msun/yr, and thus accumulated gas mass and star formation activity is stabilized as $6{\times}10^7Msun$ and ~0.02M/yr, respectively. These stabilized values are in a good agreement with estimations for the CMZ. The nuclear ring is off-centered to the Galactic center by the lopsided central mass distribution of the Galaxy model, and thus an asymmetric mass distribution is arose accordingly. The lopsidedness also leads the nuclear ring to be tilted to the Galactic plane and to precess along the Galaxy rotation. In early evolutionary stage when gas clouds start to inflow and form the nuclear ring, the z-directional oscillations of the gas clouds results in the twisted, infinity-shaped nuclear ring. Since the infinity-shaped feature is transient only for first 100 Myr, the current infinity-shape observed in the CMZ may indicate that the CMZ forms quite recently.

• Bulletin of the Korean Chemical Society
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• v.32 no.11
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• pp.3914-3922
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• 2011

3-Chloro-1-benzothiophene-2-carbonyl chloride 1 was reacted with glycine in acetone to give 3-chloro-1-benzothiophen-2-yl-carbonylaminoacetic acid 2. Various aldehydes on treatment with compound 2 in acetic anhydride to gave 1,3-oxazol-5-ones 3a-d. These oxazolones was treated with aromatic amines or hydrazides to get various imidazol-4-ones 4a-t or 5a-l. Oxazolones 3a-d was also treated with aromatic hydrazines, expansion of five member oxazole ring to six member triazine ring occurs to yield 1,2,4-triazin-6-ones 6a-h. The structures of all the synthesized compounds were confirmed by spectral data and had been screened for antibacterial activity.

• Journal of the Korean Chemical Society
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• v.55 no.5
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• pp.794-804
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• 2011

3-Chloro-1-benzothiophene-2-carbonylchloride (1) was allowed to react with glycine to give 3-chloro-1-benzothiophen-2-yl-carbonylaminoacetic acid (2). Various aldehydes were treated with compound (2) in acetic anhydride to get 1,3-oxazol-5-ones (3a-d). These oxazolones were treated with aromatic amines or hydrazides to get various imidazol-4-ones (4a-h or 5al) separately. Oxazolones was also treated with aromatic hydrazine, through which expansion of five membered oxazole ring to six member triazine ring occurs to yield 1,2,4-triazin-6-ones (6a-h). The structures of all the synthesized compounds were confirmed by spectral data and were screened for antibacterial and antifungal activities.