• 제목/요약/키워드: Loop Unfolding

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다중스레드 구조를 위한 함수형 언어의 중첩루프 펼침 (Unfolding Nested Loops of Functional Languages for Multithreaded Architectures)

  • 하상호
    • 한국정보과학회논문지:소프트웨어및응용
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    • 제29권11호
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    • pp.826-836
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    • 2002
  • Id 언어와 같은 함수형 언어의 중천루프에 포함된 미세한 수준의 대규모 병렬성을 다중스레드 구조상에서 이용하려면 프로세서뿐만 아니라, 이름공간을 위한 상당히 말은 기억공간 등의 자원이 추가로 요구된다. 이러한 병렬성을 포함하는 중첩루프론 시스템 자원 제한 없이 무분별하게 펼쳐서 실행하려고 한다면, 실행도중 기억공간의 자원의 고갈로 인하여 프로그램의 실행이 중단될 수 있다. 또한, 루프의 펼침에 따른 부담으로 인하여 프로세서의 수에 비해서 루프를 지나치게 많이 펼치는 경우에, 병렬 수행의 효과가 상당히 떨어질 수 있다. 본 논문에서는 함수형 언어의 중첩루프를 다중스레드 구조상에서 효과적으로 펼쳐서 실행할 수 있는 알고리즘을 제안하고 분석한다. 제안된 알고리즘의 특성은 주어진 중첩루프를 펼칠 시점에 프로세서 수와 기억공간의 현재 사용 가능한 시스템 자원 양에 제한하여 안전하면서도 가능한 최적으로 펼친다는데 있다.

Two Flexible Loops in Subtilisin-like Thermophilic Protease, Thermicin, from Thermoanaerobacter yonseiensis

  • Jang, Hyeung-Jin;Lee, Chang-Hun;Lee, Weon-Tae;Kim, Yu-Sam
    • BMB Reports
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    • 제35권5호
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    • pp.498-507
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    • 2002
  • A gene that encodes a thermostable protease, coined thermicin, has been isolated from Thermoanaerobacter yonseiensis that is expressed and characterized in E. coli.. In order to elucidate the molecular characteristics on thermostability of the enzyme, molecular modeling and mutagenesis technology were applied. In the modeling structure, the structural core, including the active site, was well conserved; whereas, the two loop regions were unique when compared to thermitase. The mutant enzyme with the small loop deleted (D190-I196), based on modeling structural information, showed identical enzyme activity. However, when the large loop was deleted (P233-P244), a little lower $K_m$ and even a lower kcat was found. This indicates that the large loop could influence catalytic activity. However, the unfolding temperature ($T_m$), which was determined by a differential-scanning calorimetry for the mutant enzyme deleted the small loop, was $96^{\circ}C$. This is $14^{\circ}C$ lower than that for the parent thermicin. These results suggest that the small loop may play a role in maintaining the proper folding of the enzyme at high temperatures, whereas the large loop might be related to catalysis.

다이폴 상태와 루프 상태로 변환 가능한 종이접기 방식의 종이 안테나 (Dipole- and Loop-Mode Transformable Origami Paper Antenna)

  • 이동주;서윤식;임성준
    • 한국전자파학회논문지
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    • 제27권1호
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    • pp.8-13
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    • 2016
  • 본 논문에서는 잉크젯 프린팅 기술을 이용하여 종이 필름 위에 전도성 잉크를 인쇄하여 방사 패턴 변환이 가능한 종이접기 형태의 안테나를 제안한다. 제안된 안테나는 접었을 때와 펼쳤을 때 각각 다이폴 안테나와 루프 안테나로 동작하며, 종이 필름을 접고 펼치는 방식에 따라 상호 변환될 수 있다. 제안된 안테나는 다이폴 상태와 루프 상태일 때 모두 동일하게 1.85 GHz에서 동작하도록 설계되었다. 종이 필름을 접었을 때 종이 필름의 코팅과 그 위에 인쇄된 전도성 잉크가 깨짐 현상을 해결하기 위해 액체금속(liquid metal)중 하나인 EGaIn(Eutectic Gallium Indium)을 사용하였다. 제안된 안테나의 성능은 시뮬레이션과 실제 측정 결과로 확인할 수 있으며, 다이폴 상태와 루프 상태일 때 안테나 이득은 각각 -4 dBi, -5 dBi이다. 또한, 측정 결과, 다이폴 상태와 루프 상태일 때 서로의 Null 부분을 서로 상호 보완해 주는 것을 확인할 수 있다.

Arctic Exposure: LOVELAND's Sublime Simulation of an Endless Apocalypse

  • Bishop-Stall, Reilley
    • 미술이론과 현장
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    • 제13호
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    • pp.185-213
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    • 2012
  • Charles Stankievech's 2011 installation LOVELAND includes a wall-sized screen depicting video footage of a barren arctic landscape in an enclosed room, painted and bathed in white light, that appears as an extension of the imaged environment. A melodic and industrial musical score emanates from multiple sound panels and as the music increases a cloud of purple smoke becomes visible on the horizon line in the distance and gradually advances toward the viewer until it completely fills the screen. The smoke then remains, rushing about madly and lapping at the border between the screen and the room before it suddenly subsides and the spectator is again left with the desolate landscape. The entire process takes a mere five minutes and then, fixed on an endless loop, begins again. This paper positions LOVELAND as an attempt to simulate a sublime experience of the end of the world through a transposition of the Arctic atmosphere into the gallery space. Encompassing a discussion of the historical and contemporary significance of the Arctic in popular culture, aesthetics and environmental politics, it is suggested that Stankievech employs an apocalyptic trope in reference to the unstable position of the North in the current political and ecological climate. Revisiting critiques of modernist exhibition practices and investigating the perceptual and temporal dimensions of the work, this analysis focuses primarily on the experience of the installation's spectator. Visually, aurally and phenomenologically immersed, the viewer is made subject to, and implicated in, the events unfolding on the screen and within the space. Due to the looping of the video footage, this paper argues that the apocalypse imaged in LOVELAND is presented as an endless event - incessantly enacted, yet infinitely deferred - and that the spectator is enveloped in an uncertain and unceasingly extended present moment.

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Nucleotide Sequence, Structural Investigation and Homology Modeling Studies of a Ca2+-independent α-amylase with Acidic pH-profile

  • Sajedi, Reza Hassan;Taghdir, Majid;Naderi-Manesh, Hossein;Khajeh, Khosro;Ranjbar, Bijan
    • BMB Reports
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    • 제40권3호
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    • pp.315-324
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    • 2007
  • The novel $\alpha$-amylase purified from locally isolated strain, Bacillus sp. KR-8104, (KRA) (Enzyme Microb Technol; 2005; 36: 666-671) is active in a wide range of pH. The enzyme maximum activity is at pH 4.0 and it retains 90% of activity at pH 3.5. The irreversible thermoinactivation patterns of KRA and the enzyme activity are not changed in the presence and absence of $Ca^{2+}$ and EDTA. Therefore, KRA acts as a $Ca^{2+}$-independent enzyme. Based on circular dichroism (CD) data from thermal unfolding of the enzyme recorded at 222 nm, addition of $Ca^{2+}$ and EDTA similar to its irreversible thermoinactivation, does not influence the thermal denaturation of the enzyme and its Tm. The amino acid sequence of KRA was obtained from the nucleotide sequencing of PCR products of encoding gene. The deduced amino acid sequence of the enzyme revealed a very high sequence homology to Bacillus amyloliquefaciens (BAA) (85% identity, 90% similarity) and Bacillus licheniformis $\alpha$-amylases (BLA) (81% identity, 88% similarity). To elucidate and understand these characteristics of the $\alpha$-amylase, a model of 3D structure of KRA was constructed using the crystal structure of the mutant of BLA as the platform and refined with a molecular dynamics (MD) simulation program. Interestingly enough, there is only one amino acid substitution for KRA in comparison with BLA and BAA in the region involved in the calcium-binding sites. On the other hand, there are many amino acid differences between BLA and KRA at the interface of A and B domains and around the metal triad and active site area. These alterations could have a role in stabilizing the native structure of the loop in the active site cleft and maintenance and stabilization of the putative metal triad-binding site. The amino acid differences at the active site cleft and around the catalytic residues might affect their pKa values and consequently shift its pH profile. In addition, the intrinsic fluorescence intensity of the enzyme at 350 nm does not show considerable change at pH 3.5-7.0.