• Journal of KIISE:Software and Applications
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• v.28 no.2
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• pp.201-209
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• 2001

고성능 마이크로 프로세서들은 성능 향상을 위해 ILP를 지원한다. 병렬성을 극대화시키기 위해서는 많은 성능 저해 요인들을 제거해야 한다. 최근에는 컴파일러의 역할을 증대시켜 이러한 요인들을 줄이기 위한 노력들이 활발히 진행되고 있다. 본 논문에서는 성능 저해 요인인 조건 분기 처리를 위하여 조건 실행과 레지스터 할당을 결합함으로써 메모리로의 대피를 최소화하고 병렬성을 향상시킬 수 있는 개선된 레지스터 할당 알고리즘을 제안한다. 제안한 방법을 적용하여 실험한 결과 간섭 그래프의 에지수가 4.47% 감소되었고 그 결과 요구되는 대피 변수의 수도 21.35% 감소되었다. 그리고 기존의 방법에 비해 19.38%의 성능 향상 결과를 얻었다. 결국 본 레지스터 할당 기법은 조건 실행을 통해 조건 분기 명령을 제거하여 기본 블록 내의 명령어 수를 증가시켜 병렬처리의 기회를 증진시키고 조건 분석을 통해 간섭 그래프의 불필요한 에너지를 제거시켜 보다 효율적인 레지스터 할당을 실현함으로써 제안한 방법의 타당성을 검증하였다.

• Proceedings of the Korean Information Science Society Conference
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• 2003.04a
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• pp.130-132
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• 2003

계산 과학을 사용하는 응용 분야는 공학, 물리, 화학, 생명 과학에서 경제학까지 다양하다. 계산 과학에 사용되는 많은 알고리즘들은 행렬 연산을 포함하고 있으며 이 행렬은 크기가 크고 대부분의 원소가 0값을 갖는 희소 행렬일 경우가 많다. 본 논문에서는 희소 행렬의 연산 중, 희소 행렬 A와 밀집 벡터 x, y에 대하여 ylongleftarrowy＋Ax와 ylongleftarrowy＋$A^{T}$ Ax 의 두 가지 연산에 대한 계산 속도 개선 방법으로서 레지스터 재사용을 높이는 레지스터 블록화와 캐쉬 미스를 줄이기 위한 캐쉬 최적화 방법을 제안하며 또한 희소 행렬의 특성과 target 컴퓨터의 구조에 따라 정해지는 레지스터 블록 크기를 결정하는 방법을 설명한다. Preliminary결과로 이 방법을 Pentium III system상에서 실험한 결과를 보이는데 ylongleftarrowy＋Ax 의 연산에 대하여는 2.5 배, ylongleftarrowy＋$A^{T}$ Ax 의 연산에 대하여는 3.5 배까지의 성능 개선을 이룰 수 있다.

• Journal of KIISE:Computer Systems and Theory
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• v.35 no.12
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• pp.540-551
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• 2008

Today's microprocessor designs are not free from temperature as well as power consumption. As processor technology scales down, an on-chip circuitry increases power density, which incurs excessive temperature (hotspot) problem. To tackle thermal problems cost-effectively, Dynamic Thermal Management (DTM) has been suggested: DTM techniques have benefits of thermal reliability and cooling cost. However, they require trade-off between thermal control and performance loss. This paper proposes a dual integer register file structure to minimize the performance degradation due to DTM invocations. In on-chip thermal control, the most important functional unit is an integer register file. It is the hotspot unit because of frequent read and write data accesses. The proposed dual integer register file migrates read data accesses by adding an extra register file, thus reduces per-unit dynamic power dissipation. As a result, the proposed structure completely eliminates localized hotspots in the integer register file, resulting in much less performance degradation by average 13.35% (maximum 18%) improvement compared to the conventional DTM architecture.

• Journal of the Korean earth science society
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• v.31 no.7
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• pp.785-797
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• 2010

This study identified the linguistic features of Earth science treatises through the analysis of the register. Data included three Korean treatises that were in geology, atmospheric science, and oceanography. The register of Earth science treatise was as follows: First, there were semantic, referential connections between Themes and Rhemes, that the messages and main points of the texts were expressed coherently and cohesively. Second, some predicates were used which were related to deductive inference, abductive inferences, or causal relation according to the genre elements of each text. The logical relations were not represented by the conjunctions but by the types of predicates. Third, most texts in the treatises showed interpersonally weak relationship using mental predicates related to possibilities, which meant scientists expressed indirectly their interpretation, explanation, or arguments. From these results, we argued that some activities of unpacking the language of science be included in science curriculum in order to improve students' literacy of science texts and understanding scientists' knowledge construction.

• Journal of KIISE:Computer Systems and Theory
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• v.27 no.2
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• pp.200-208
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• 2000

Multi-ports register could shared several instructions at the same time in read operation. We address a formal methods for describing timing analysis and resource restriction in pipeline super scalar process that having multi-Port registers. First, we specify in-order pipeline instructions, and then, extend timing analysis in out-of-order super-scalar. In this case, we find instruction pairs in any cycle which can execute same time, We use ACSR(Algebra of Communicating Shared Resources), a branch of formal methods based on process algebra, for instruction specification and modelling.

• Journal of KIISE:Computer Systems and Theory
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• v.26 no.10
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• pp.1217-1224
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• 1999

이동 호스트들의 위치 정보를 관리하는 것은 이동 컴퓨터 시스템에서 중요한 문제이다. 이동 호스트가 이동할 때 위치 수정과 위치 탐색간에는 상반관계가 존재한다. 본 논문에서는 위치 서버를 이용한 간단한 quorum 기반 분산 동적 위치 관리 방법을 제안한다. 이 방법에서는 이동 호스트들의 위치 정보가 모든 위치 레지스터가 아닌 위치 레지스터들의 부분집합에서 효율적으로 관리되기 때문에 위치 수정 비용과 위치 탐색 비용이 감소된다. 그리고 위치 레지스터들의 부분집합은 동적으로 변하고, 각 위치 서버의 부하는 이동 호스트에 대한 질의율을 고려하므로 균등해진다. 제안된 알고리즘의 성능은 위치 수정비용과 위치 탐색비용의 전체비용으로 평가되었고, Prakash의 알고리즘과 비교되었다.Abstract Managing location information of mobile hosts is an important issue in mobile computing systems. There is a trade-off between location update and search, when a mobile host moves. This paper proposes a simple quorum-based distributed dynamic location management method using location registers. The cost of location updates and searches is reduced by our method because the location information of mobile hosts is managed efficiently in a subset of location registers instead of in all location registers. In our method, the subset of location registers is dynamically changed, and the load of each location register is balanced by considering query rate for mobile hosts. The performance of proposed algorithm is evaluated in terms of the total cost of a location update and a location search, and is compared with Prakash's algorithm.

• Journal of the Korean earth science society
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• v.32 no.1
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• pp.84-98
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• 2011

The study investigated the linguistic characteristics of middle school students' writing on the themes of earth science through analysis of its genre and register. Data for analysis included $7^{th}$ grade and $9^{th}$ grade students' writings about 'global warming' and 'classification of rocks'. The results of this study include: First, many students were not accustomed to writing in genre, especially exposition genre. Second, in terms of ideational meaning, the material verbs representing action or doing were more dominant than relational verbs that are related to the attribute or definition of things, and additional logical relations were predominant. Third, regarding interpersonal meaning, agents, emotions, subjective opinions appeared in the writings and students did not express their ideas conclusively and revealed feelings of doubt and uncertainty about their knowledge. Fourth, as for textual meaning, most students listed fragments of information using additional conjunctions in simple structures and were not accustomed to writing texts with organizing structures, logical patterns, cohesion, and coherence. From these results, we argued that the scientific writings should be emphasized in science learning that aims to foster scientific literacy. In addition, we discussed the necessity of improving science teachers' perceptions on scientific writing as well as setting up a specific plan in the national curriculum.

• Journal of KIISE:Software and Applications
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• v.26 no.4
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• pp.557-567
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• 1999

본 논문은 데이터 캐시를 효과적으로 사용하기 위하여 개발된 원시 프로그램의 루프 변환체제에 대하여 논하고 있다. DIUS로 명명된 이 체계는 외부 루프 펼침을 중심으로 루프 분산, 교환이 선행되고 , 마직막에 스칼라화가 적용되는 변환체계이다. 루프 교환은 회전 공간이 루프 단위로 변형되어 전반적으로 캐시 재사용 기회를 높이지만 일부 배열 참조에 대해서는 오히려 재사용 기회를 감소시킨다. 본 연구에서는 이 문제를 외부 루프 펼침으로 해결하였다. 외부 루프 펼침과 루프 교환을 루프 몸체의 문장들에 선별적으로 적용하기 위하여 루프 분산을 도입하였다. 외부 루프 펼침을 적용하면 배열 참조를 스칼라 참조로 변환하는 스칼라화의 효과가 증대되어 레지스터 사용의 효율성이 높아진다. SPEC CFP95 벤치마크에 대하여 DIUS를 적용한 결과 기하학적 평균으로 속도 향상 1.10을 얻었으며, 특정 프로그램들은 모두 캐시 미스수가 줄어들었음을 확인하였다. 이와 같은 성능향상은사용된 루프 변환기법들이 갖는 캐시와 레지스터의 효율적인 사용에 기인한다.

• Journal of KIISE:Computer Systems and Theory
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• v.30 no.9
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• pp.512-522
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• 2003

For a time-multiplexed FPGA, a circuit is partitioned into several subcircuits, so that they temporally share the same physical FPGA device by hardware reconfiguration. In these architectures, all the hardware reconfiguration information called contexts are generated and downloaded into the chip, and then the pre-scheduled context switches occur properly and timely. Typically, the size of the chip required to implement the circuit depends on both the maximum number of the LUT blocks required to implement the function of each subcircuit and the maximum number of micro-registers to store results over context switches in the same time. Therefore, many partitioning or synthesis methods try to minimize these two factors. In this paper, we present a new estimation technique to find the lower bound on the number of micro-registers which can be obtained by any synthesis methods, respectively, without performing any actual synthesis and/or design space exploration. The lower bound estimation is very important in sense that it greatly helps to evaluate the results of the previous work and even the future work. If the estimated lower bound exactly matches the actual number in the actual design result, we can say that the result is guaranteed to be optimal. In contrast, if they do not match, the following two cases are expected: we might estimate a better (more exact) lower bound or we find a new synthesis result better than those of the previous work. Our experimental results show that there are some differences between the numbers of micro-registers and our estimated lower bounds. One reason for these differences seems that our estimation tries to estimate the result with the minimum micro-registers among all the possible candidates, regardless of usage of other resources such as LUTs, while the previous work takes into account both LUTs and micro-registers. In addition, it implies that our method may have some limitation on exact estimation due to the complexity of the problem itself in sense that it is much more complicated than LUT estimation and thus needs more improvement, and/or there may exist some other synthesis results better than those of the previous work.

• Journal of the Korean earth science society
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• v.31 no.1
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• pp.51-62
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• 2010

The purpose of this study was to investigate how a science magazine played a role in filling the gap between scientists and the general public, and how it contributed to science popularization. We analyzed the linguistic features of the texts used in a science magazine. We used 12 articles (six written by journalists, and six written by scientists) from the Science Donga. Register analysis was conducted in order to define the linguistic features of the texts in terms of ideational meaning, interpersonal meaning and, textual meaning. Results of this study are as follows: (1) the articles written by journalists used a higher mental and verbal processes in which the conversations and thoughts of scientists were expressed. (2) Human agents were relatively explicit in the journalists' articles. However, they were implicit or omitted in the articles of scientists. (3) Interrogative sentences and inclusive imperative sentences, and even omissions were frequently found in the journalists' articles whereas scientists' articles mainly used declarative statements. (4) The clause density of journalist' articles and scientists' were similarly lower than that of science textbooks. (5) The information structure revealed by the patterns of Theme and Rheme that the journalists' articles used in science magazines was simpler than that of science textbooks, while the structure of scientists' articles was more complex than that of journalists'. Based on the linguistic features of the texts used in science magazines, we found that a science magazine contributes to science popularization in two faces: One is in that the articles of journalists present science contents in a way that the readers can follow with ease and feel well-acquainted. The other is that the modified articles of scientists help the general public get familiar with the culuture of science in terms of use of science language.