• Journal of KIISE:Computer Systems and Theory
• /
• v.27 no.2
• /
• pp.177-187
• /
• 2000

In the past several years, many systems which adopted ring topology with high-speed unidirectional point-to-point links have emerged to overcome the limit of bus for interconnection network of clustered multiprocessor system. However, rapid increase of processor speed and performance improvement of local bus and memory system limit scalability of system with point-to-point link of standard bandwidth. Therefore, necessity to extend bandwidth is emphasized. In this paper, we adopt PANDA system as base model, which is clustering-based multiprocessor system. By simulating a model adopting commercial processor and local bus specification, we show that point-to-point link is bottleneck of system performance, and bandwidth expansion by more than 200% is needed. To expand bandwidth of interconnection network, it needs excessive design cost and time to develop new point-to-point link with doubled bandwidth. As an alternative to double bandwidth, we propose several ways to implement dual ring -simple dual ring, transaction-separated dual ring, direction-separated dual ring- by using off-the-shelf point-to-point links with IEEE standard bandwidth. We analyze pros. and cons. of each model compared with doubled-bandwidth single ring by simulation.

• Journal of Integrative Natural Science
• /
• v.8 no.4
• /
• pp.313-316
• /
• 2015

In this article, we compute the order of a general linear group $GL_n(A)$ over a finite ring A.

• Transactions of the Korean Society of Automotive Engineers
• /
• v.8 no.4
• /
• pp.1-9
• /
• 2000

To understand the thermal characteristics around the piston ring gap ring gap positions and piston temperatures are measured simultaneously. The locations of piston ring gap are measured by the radio-tracer method and piston temperature are measured by a K-type thermocouple and scissors type linkage system. From these experiments following facts are clarified. Piston temperatures fluctuate according to the piston ring rotation. And the temperature fluctuation is mainly affected by top ring gap position irrelevant to the second ring fop position. If the top ring gap position increases and the temperature of top ring groove shows maximum value when top rin gap position coincide with temperature measuring point. The maximum amplitude of temperature fluctuation which is proportional to the blow by gas rate is around 12-15$^{\circ}C$.

• Transactions of the Korean Society of Pressure Vessels and Piping
• /
• v.11 no.1
• /
• pp.61-68
• /
• 2015

The function of Feed Water Ring is to provide the flow path from Feedwater Nozzle to inside of SG(steam generator). Significant amounts of general FAC on the outside of the Feed Water Ring are not likely due to the low flow velocities in this area. However, on the interior of the Feed Water Ring, there may be areas of local higher flow velocity which could lead to higher FAC rates. These may include the inlet tee from the Feedwater Nozzle into the Feed Water Ring, the areas where the Feed Water Ring changes diameter, and especially the entrance area to the J-Nozzles. In this paper, the results of root cause analysis of through-wall hole observed at domestic WH 51F SG Feed Water Ring and its effect on the integrity and performance of SG are described. And, the maintenance strategy for WH 51F SG Feed Water Ring and the monitoring strategy for Downcomer Feed Water Ring of CE System 80 SG are presented.

• Journal of Biomedical Engineering Research
• /
• v.30 no.6
• /
• pp.476-481
• /
• 2009

The most troublesome artifacts in micro computed tomography (micro-CT) are ring artifacts. The ring artifacts are caused by non-uniform sensitivity and defective pixels of the x-ray detector. These ring artifacts seriously degrade the quality of CT images. In flat-panel detector based micro-CT systems, the ring artifacts are hardly removed by conventional correction methods of digital radiography, because very small difference of detector pixel signals may make severe ring artifacts. This paper presents a novel method to remove ring artifacts in flat-panel detector based micro-CT systems. First, the bad lines of a sinogram which are caused by defective pixels of the detector are identified, and then, they are corrected using a cubic spline interpolation technique. Finally, a ring artifacts free image is reconstructed from the corrected projections. We applied the method to various kinds of objects and found that the image qualities were much improved.

• Tribology and Lubricants
• /
• v.7 no.1
• /
• pp.28-34
• /
• 1991

The performance of the counterrotating floating ring journal bearing is analysed with isothermal finite bearing theory. The effect of counterrotating speed of the sleeve on the performance of the bearing is investigated. It is shown that counterrotating floating ring journal bearings properly designed can have considerable load capacity at the same counterrotating speed, while conventional circular journal bearing with one fluid film cannot. Investigating the relationship between the frictional torques on the ring due to the inner and outer films and the rotational speed of the ring, the stability of the equilibrium state is identified and the operating characteristics of the counterrotating floating ring journal bearing according to the method of acceleration or deceleration of the rotational speeds of the journal and sleeve are clarified. It is theoretically confirmed that floating ring journal bearings can be used in counterrotating journal-bearing system and become good substitutes for rolling bearings in counterrotating systems.

• KSII Transactions on Internet and Information Systems (TIIS)
• /
• v.10 no.12
• /
• pp.5553-5571
• /
• 2016

In this paper, we introduce a new concept called generalized ring signcryption (GRSC), which can achieve ring signature and ring signcryption functions with only one key pair and one algorithm. It is very useful for a system which has a large number of users, or has limited storage space, or whose function requirements may be changed later. We give a formal definition and a security model of GRSC and propose a concrete scheme based on bilinear pairings. In the random oracle model, the scheme's confidentiality can be proved under the GBDH assumption, and its unforgeability can be proved under GDH' assumption, and what is more, this scheme also allows unconditional anonymity. Compared with other identity-based ring signcryption schemes that use bilinear pairings as well, our scheme is a highly efficient one.

• Transactions of the Korean Society of Mechanical Engineers A
• /
• v.27 no.11
• /
• pp.1949-1957
• /
• 2003

A hybrid finite element analysis was used to analyze the influence of ring gear rim thickness and spline number on the static properties of a planetary gear system with manufacturing errors. Both of these parameters affected the bearing force and critical stress. The effect of changes in the rim thickness on the load sharing between the gears depended on the type of manufacturing error. Ring flexibility improved the load sharing between planetary gears only in systems with planet tooth thickness or planet tangential errors; for other types of error, ring flexibility worsened the load sharing. To improve load sharing, rim thickness and spline number should be controlled within a specific range. The minimum rim thickness limit should be determined considering not only the critical stress but also the load sharing. The effect of the ring gear boundary condition was more apparent in a system with errors than in a normal system.

• Journal of Power System Engineering
• /
• v.16 no.5
• /
• pp.63-69
• /
• 2012

This paper presents an analysis on the induction heating of ring flange for wind farm. Ring flange is used for the connection of poles when building a column of wind power plant. Heat treatment of ring flange with the diameter of ${\O}1,000mm$ has been considered. For analysis on the induction heating, FEA is used. Firstly, electromagnetic filed analysis was performed to get the induction current distribution on the steel, After that, heat transfer analysis was performed using the magnetic filed analysis results. for more precise analysis, some measurement for permeability has been performed and the measurement data was used during the analysis. From the analysis, we get the temperature distribution on the ring flange.

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