• Journal of KIISE:Computer Systems and Theory
• /
• v.30 no.1
• /
• pp.1-11
• /
• 2003

Fragmentation is the main performance bottleneck of large, multi-user multicomputer system. This paper presents an L-Shaped Submesh Allocation(LSSA) strategy, which lifts the restriction on the rectangular shape formed by allocated processors in order to address the problem of fragmentation. LSSA can manipulate the shape of the required submesh to fit into the fragmented mesh system. Thus, LSSA accommodates incoming jobs faster than other strategies and results in the reduction of job response time. Extensive simulations show that LSSA performs more efficiently than other strategies in terms of the external fragmentation, the job response time and the system utilization.

• Proceedings of the Korean Information Science Society Conference
• /
• 2000.10c
• /
• pp.656-658
• /
• 2000

상호연결망으로 메쉬 구조를 채택한 대규모 병렬처리 시스템에 대해서 제안된 기존의 프로세서 할당기법들은 직사각형 모양의 서브메쉬 할당 기법으로 제한되어왔다. 그 결과 기존의 기법들은 심각한 시스템의 단편화를 초래하는 문제를 갖고 있다. 본 논문에서는 외부 프래그멘테이션과 작업 응답 시간을 동시에 줄이기 위해서, 단편화된 메쉬 시스템에도 적용될 수 있도록 직사각형뿐만 아니라 변형된 L자 모양의 서브메쉬를 할당하는 확장된 LSSA(L-Shaped Submesh Allocation) 기법을 제안한다. LSSA 기법에서 수행되는 모든 서브메쉬 모양의 변형들은 응용 프로그래머에서 투명성을 보장한다. 시뮬레이션 결과를 통해서 LSSA 기법이 작업 응답 시간과 시스템의 활용도 면에서 다른 기법들보다 우수함을 보인다.

• Journal of Ocean Engineering and Technology
• /
• v.12 no.3 s.29
• /
• pp.31-41
• /
• 1998

Single fiber fragmentation technique was used to evaluate the change of interfacial properties by degradation of fiber tensile strength in the fiber reinforced composites. The influences of fiber tensile strength on the interfacial properties have been evaluated by the fragmentation specimens(weak fiber samples) of glass fiber/epoxy resin that was made using the pre-degraded glass fiber in distilled water at $80^{circ}C$ for specified periods. The effects of the immersion time on the interfacial properties in the distilled water at $80^{circ}C$ also have been evaluated by the fragmentation specimens(original fiber samples) of glass fiber/epoxy resin that was made using the received glass fiber. As the result, the tensile strength of glass fiber was decreased with the increasing of the treatment time in the distilled water at $80^{circ}C$ and the interfacial shear strength was independent of the change of the glass fiber strength in the single fiber fragmentation test. But in the durability test using the single fiber fragmentation specimen, interfacial shear strength decreased with the increasing of the immersion time in distilled water ar $80^{circ}C$. And it turned out that the evaluating of interfacial shear strength using original fiber tensile strength was valuable in the durability test for the water environment by the single fiber fragmentation technique.