• Proceedings of the Korean Information Science Society Conference
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• 2000.04a
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• pp.9-11
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• 2000

최근에 캐쉬의 성능이 전체 시스템에 미치는 영향이 커짐에 따라 캐쉬의 성능을 모델링하고 향상시키기 위한 많은 연구가 진행되고 있다. 본 논문에서는 네 가지 종류의 캐쉬모델을 가정하고 분기명령어 비율, 캐쉬미스율, 분기예측 실패율 등의 파라메터를 이용하여 수퍼스칼라 프로세서에서의 명령어 패치율을 해석적으로 모델링하였다. 시뮬레이션 결과 분기예측실패가 명령어 패치율에 미치는 영향보다는 캐쉬미스율이나 캐쉬미스 패널티의 증가로 인한 패치율의 감소가 더욱 큰 폭으로 나타났다.

• Tunnel and Underground Space
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• v.24 no.5
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• pp.344-353
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• 2014

In this study, the behavior of rock pillar in the diverging area of road tunnel was assessed by using a three dimensional numerical analysis. Based on parameters affecting the behavior of rock pillar, different safety factors according to pillar width, depth and rock conditions were evaluated. It turned out that as the pillar width increases, the change curve of safety factors in accordance with depth and rock conditions shows more of the nonlinear behavior. By the assessment of the minimum safety factor, a safety factor chart on the behavior of rock pillar in the diverging area of road tunnel was suggested.

• Journal of the Korean Geosynthetics Society
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• v.14 no.2
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• pp.81-88
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• 2015

This study assessed the behavior of rock pillar in tunnel diverging area by using a three dimensional numerical analysis. Based on parameters affecting the behavior of rock pillar, this study evaluated different safety factors according to pillar width, depth and rock conditions. It turned out that as the rock pillar width increases, the change curve of safety factors in accordance with depth and rock conditions shows more of the nonlinear behavior. By the assessment of the minimum safety factor, a safety factor chart on the behavior of rock pillar in tunnel diverging area was suggested.

• The Transactions of the Korea Information Processing Society
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• v.5 no.10
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• pp.2676-2685
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• 1998

In order to improve the branch prediction accuracy and to reduce the BTB miss rate, this paper proposes a two-level BTB structure that adds small-sized victim BTB to the convetional BTB. With small cost, two-level BTB can reduce the BTB miss rate as well as improve the prediction accuracy of the hybrid branch prediction strategy which combines dynamic prediction and static prediction. Through the trace-driven simulation of four bechmark programs, the performance improvement by the proposed two-level BTB structure is analysed and validated. Our proposed BTB structure can improve the BTB miss rate by 26.5% and the misprediction rate by 26.75%

• The KIPS Transactions:PartA
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• v.19A no.2
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• pp.77-84
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• 2012

Speculative execution for improving instruction-level parallelism is widely used in high-performance processors. In the speculative execution technique, the most important factor is the accuracy of branch predictor. Unfortunately, complex branch predictors for improving the accuracy can cause serious thermal problems in 3D multicore processors. Thermal problems have negative impact on the processor performance. This paper analyzes two methods to solve the thermal problems in the branch predictor of 3D multi-core processors. First method is dynamic thermal management which turns off the execution of the branch predictor when the temperature of the branch predictor exceeds the threshold. Second method is thermal-aware branch predictor placement policy by considering each layer's temperature in 3D multi-core processors. According to our evaluation, the branch predictor placement policy shows that average temperature is $87.69^{\circ}C$, and average maximum temperature gradient is $11.17^{\circ}C$. And, dynamic thermal management shows that average temperature is $89.64^{\circ}C$ and average maximum temperature gradient is $17.62^{\circ}C$. Proposed branch predictor placement policy has superior thermal efficiency than the dynamic thermal management. In the perspective of performance, the proposed branch predictor placement policy degrades the performance by 3.61%, while the dynamic thermal management degrades the performance by 27.66%.

• Journal of the Speleological Society of Korea
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• no.62
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• pp.1-9
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• 2004

The main purpose of this paper is to clarify the relationship between the development of the Uro cave and the characteristics of the landform development. The mountain systems of the study area are north-western part. central part and south-eastern part. The third order streams are developed, and the bifurcation ratios are 7.0 and 4.0. The drainage density and the networks of the streams are not well developed in this area. The rocks of this area are sedimentary rocks, metamorphic rocks and Igneous rocks. The soils are lithosol, and red-brownish soils.

• Journal of the Korean Geosynthetics Society
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• v.15 no.4
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• pp.17-23
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• 2016

This study assessed the behavior of rock pillar in tunnel asymmetric diverging area by using a three dimensional numerical analysis. The stability of pillar is very important for the ensure the stability of the tunnel asymmetric diverging area. Based on parameters affecting the behavior of rock pillar, this study evaluated different safety factors according to pillar width, depth and rock conditions. It turned out that as the rock pillar width increases, the change curve of safety factors in accordance with depth and rock conditions shows more of the nonlinear behavior. By the assessment of the minimum safety factor, a safety factor chart on the behavior of rock pillar in tunnel asymmetric diverging area was suggested.

• The KIPS Transactions:PartA
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• v.9A no.4
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• pp.497-502
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• 2002

Conditional branches can severely limit the performance of instruction level parallelism by causing branch penalties. 2-level adaptive branch predictors were developed to get accurate branch prediction in high performance superscalar processors. Although 2 level adaptive branch predictors achieve very high prediction accuracy, they tend to be very costly. In this paper, set-associative cached correlated 2-level branch predictors are proposed to overcome the cost problem in conventional 2-level adaptive branch predictors. According to simulation results, cached correlated predictors deliver higher prediction accuracy than conventional predictors at a significantly lower cost. The best misprediction rates of global and local cached correlated predictors using set-associative caches are 5.99% and 6.28% respectively. They achieve 54% and 17% improvements over those of the conventional 2-level adaptive branch predictors.

• 주택과사람들
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• s.91
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• pp.84-84
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• 1997

• Proceedings of the KAIS Fall Conference
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• 2011.12b
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• pp.379-381
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• 2011

본 논문에서는 피복아크용접(SMAW)을 자동용접으로(GMAW) 전환시키기 위한 기초 연구로서 GMA용접가스가 기공율에 미치는 영향을 보고자 한다. 기공율 평가를 위해 반자동 소방용 분기배관실험장치를 제작하였다. 분기배관의 기공율을 평가하기 위해 보호가스 3종(Ar, $CO_2$, 8:2 혼합가스), 전압을 변수로 설정하여 GMA용접을 실시하였다. 용접을 실시한 시편을 용접방향으로 절단하여 기공율 평가를 실시하였다.