• Journal of the Korean Vacuum Society
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• v.1 no.3
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• pp.336-340
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• 1992

포항가속기 저장링 진공시스템의 성능을 예견하기 위하여, 초도품 진공 챔버를 제 작, 조립 및 테스트를 하였다. 비휘발성 흡착펌프와 이온펌프로 구성되어 있는 다섯대의 혼 합펌프와 한 대의 터보펌프를 사용하였다. 그 결과 낮은 10-10Torr을 얻음으로서 설계된 진 공도를 성취하였다.

• 전기의세계
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• v.38 no.5
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• pp.5-17
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• 1989

포항공과대학은 대단위 연구기설의 하나로서 740억원 규모의 제3세대 방사광가속기(PLS)를 건설키로 확정하고 1988년 4월 이의 추진에 착수하였다. 이 시설 및 추진현황을 소개하고자 한다.

• 대학교육
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• s.32
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• pp.136-143
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• 1988

• KLA journal
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• v.31 no.1 s.260
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• pp.46-46
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• 1990

• 대학교육
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• s.128
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• pp.52-61
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• 2004

• Journal of Science and Technology Studies
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• v.10 no.2
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• pp.37-76
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• 2010

Park Tae-Joon, a pioneer in the Korean steel industry, has greatly influenced the advancement of science and technology as well as the development of the nation's economy. He believed that POSCO, which was a government-owned company, should not only focus on making profits, but also operate for higher state-level purposes. This belief became the basis for founding a general laboratory and a research university, as well as building big science and technology R&D facilities. Park Tae-Joon's efforts to establish a research university and his dedication to the advancement of science education stemmed from his devotion to public welfare. Just like he believed that the steel industry, which is the basis for all other industries, should be promoted at the state-level, he believed that university and basic science should also be promoted at the state-level. Thanks to his philosophy, the Pohang University of Science and Technology has risen beyond just a polytechnic school to become a research university that makes revolutionary science and technology advancements for the nation. The fact that Park Tae-Joon used profits from business to build the university and national research facilities such as the Pohang Light Source also shows that he nurtured pure science with the welfare of the whole nation in mind.

• Korean Journal of Metals and Materials
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• v.47 no.1
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• pp.50-58
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• 2009

In this study, alumina matrix composites reinforced with carbon nanotubes (CNTs) were fabricated by ultrasonic dispersion, ball milling, mixing, compaction, and sintering processes, and their relative density, electrical resistance, hardness, flexure strength, and fracture toughness were evaluated. 0~3 vol.% of CNTs were relatively homogeneously dispersed in the composites in spite of the existence of some pores. The three-point bending test results indicated that the flexure strength increased with increasing volume fraction of CNTs, and reached the maximum when the CNT fraction was 1.5 vol.%. The fracture toughness increased as the CNT fraction increased, and the fracture toughness of the composite containing 3 vol.% of CNTs was higher by 40% than that of the monolithic alumina. According to observation of the crack propagation path after the indentation fracture test, a new toughening mechanism of grain interface bridging-induced CNT bridging was suggested to explain the improvement of fracture toughness in the alumina matrix composites reinforced with CNTs.

• Journal of the Korean Society for Precision Engineering
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• v.11 no.1
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• pp.138-149
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• 1994

This paper introduces a new monitoring technique which utilizes an adaptive signal processing for feature generation, coupled with a multilayered merual network for pattern recognition. The cutting force signal in face milling operation was modeled by a low order discrete autoregressive model, shere parameters were estimated recursively at each sampling instant using a parameter adaptation algorithm based on an RLS(recursive least square) method with discounted measurements. The influences of the adaptation algorithm parameters as well as some considerations for modeling on the estimation results are discussed. The sensitivity of the extimated model parameters to the tool state(new and worn tool)is presented, and the application of a multilayered neural network to tool state monitoring using the previously generated features is also demonstrated with a high success rate. The methodology turned out to be quite suitable for in-process tool wear monitoring in the sense that the model parameters are effective as tool state features in milling operation and that the classifier successfully maps the sensors data to correct output decision.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.14 no.4
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• pp.135-140
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• 2004

The ID-based cryptosystem and Power Analysis Attack are attracting many researchers and have been developed aggressively to date. Especially, DPA (Differential Power Analysis) attack has been considered to be the most powerful attack against low power devices, such as smart cards. However, these two leading topics are researched independently and have little hewn relations with each other. In this paper, we investigate the effect of power analysis attack against ID based cryptosystem. As a result, we insist that ID-based cryptosystem is secure against DPA and we only need to defend against SPA (Simple Power Analysis).

• Korean Journal of Metals and Materials
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• v.46 no.9
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• pp.563-571
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• 2008

The influence of annealing treatment on dynamic deformation behavior of ultra-fine grained aluminum alloys was investigated in this study. After equal-channel angular pressing at $200^{\circ}C$, most of the grains were considerably reduced to nearly equiaxed grains of $0.3{\mu}m$ in size. With an increment of various annealing treatments for 1 hour, resultant microstructures were found to be fairly stable at temperatures up to $200^{\circ}C$, suggesting that static recovery would be dominantly operative, whereas grain growth was pronounced above $250^{\circ}C$. The tensile test results showed that yield and ultimate tensile strengths decreased, but elongation-to-failure and strain hardening rate increased with increasing annealing temperature. The dynamic deformation behavior retrieved with a series of torsional tests was explored with respect to annealed microstructures. Such mechanical response was analyzed in relation to resultant microstructure and fracture mode.