• Proceedings of the Korean Information Science Society Conference
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• 2012.06a
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• pp.265-267
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• 2012

최근 들어, 하드웨어 플랫폼은 다수의 코어 아키텍처의 메모리 대역폭을 유지하기 위해 NUMA 구조로 설계되고 있다. 이러한 NUMA 시스템 구조에서 다른 노드의 메모리에 접근할 경우, 더 많은 시간과 비용이 소모된다. 따라서 이를 고려한 스케줄링 기법들이 가상화 혹은 가상화되지 않은 시스템 환경에서 연구되고 있다. 하지만, 아직까지 NUMA 시스템 가상화 환경에서 리모트 접근을 제거함과 동시에 이에 따른 오버헤드를 최소화하는 연구는 없었다. 따라서 본 논문에서는 이러한 환경에서 메모리 접근 지연을 줄이기 위한 VCPU 스케줄링 기법을 제안한다. 본 기법은 노드별 페이지 테이블 관리, LRU 기반 게스트 스케줄러, 캐시 오염 태스크 전용 버퍼 관리 기술을 이용한다. 다른 기법들과의 비교 및 분석 결과에서 알 수 있듯이, 본 기법을 적용할 경우 NUMA 시스템 노드 간 리모트 접근을 없애고, 이에 따른 오버헤드를 최소화하며, 주어진 하드웨어 캐시를 효율적으로 사용할 수 있다.

• Journal of Life Science
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• v.12 no.1
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• pp.33-42
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• 2002

In several species, a short period of ischemic preconditioning protects the heart by reducing the size of infarcts resulting from subsequent prolonged bouts of ischemia. The mechanism by which activation of ATP-sensitive $K^+$($K_ATP$) channels could provide the memory associated with ischemic preconditioning is still under debate. Several signal transduction pathways have been implicated in the mechanisms of protection induced by ischemic preconditioning. The exact receptor-coupled pathways involved in preconditioning remain to be identified. Likely extracellular agonists are those whose circulating levels increase under conditions that activate $K_ATP$ channels; these conditions include ischemia and ischemic preconditioning. Potential physiological agonists include the following: (1) nitric oxide; (2) catecholamine; (3) adenosine; (4) acetylcholine; (5) bradykinin and (6) prostacycline. The purpose of this review was to understand the mechanism by which biological signal transduction mechanism acts as a link in one or more known receptor-mediated pathways to increase $K_ATP$ channel activity during ischemic preconditioning.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.21 no.3
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• pp.361-368
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• 1997

In order to eliminate position errors existing at the steady state in the motion control of robotic manipulators, a new fuzzy control algorithm is propeosed using three variables, position error, velocity error and integral of position errors as input variables of the fuzzy controller. Although the number of input variables of the fuzzy controller is increased from two to three, the number of fuzzy control rules is just increased by two. Three dimensional look-up table is used to reduce the computational time in real-time control, and a technique reducing the amount of necessary memory is introduced. Simulation and experimental studies show that the position errors at the steady state are decreased more than 90% compared to those of existing fuzzy controller when the proposed fuzzy controller is applied to the 2 axis direct drive SCARA robot manipulator.

• Journal of information and communication convergence engineering
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• v.9 no.3
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• pp.266-270
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• 2011

The advancement of technology enables smart phones or handheld devices to render complex 3D graphics. However, the processing power and memory of smart phones remain very limited to render high polygon and details 3D models especially on games which requires animation, physic engine, or augmented reality. In this paper, several techniques will be introduced to speed up the computation and reducing the number of vertices of the 3D meshes without losing much detail.

• The KIPS Transactions:PartA
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• v.11A no.1
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• pp.67-74
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• 2004

Most of today's parallel numerical schemes use synchronous algorithms, where some processors that have finished their tasks earlier than others must wait at synchronization points for correct computation. Hence overall performance of the system is dependent upon the speed of the slowest processor. In this paper, we det·ise a synchronous/asynchronous hybrid algorithm to accelerate convergence of the solution for finding the dominant eigenpair of a large matrix, by reducing the idle times of faster processors using MPMD programming methodology.

• Proceedings of the KIEE Conference
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• 1992.07b
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• pp.573-576
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• 1992

This paper presents a method, which couples the boundary integral terms in the thin magnetic materials with standard FEM used to analyze the rest of it, for analyzing the magnetic fields. The proposed method retains the sparsity and symmetry of the final system matrix, the merits of standard FEM and eliminates the need for fininte elements in the thin magnetic materials, thereby reducing necessary capacity of computer memory and computing time. To verify the usefulness of the proposed alogorithmn, an examples, coil with source currents and thin magnetic materials, is chosen and analyzed. the results are compared with those of the standard FEM by coarse mesh and the proposed method, using standard FEM by fine mesh as a reference.

• Proceedings of the KIEE Conference
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• 2009.07a
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• pp.1595_1596
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• 2009

In this study reduction effects of magnetic field were analyzed using multi-conductor method in analysis of shield. The method can be effective in the analysis because of reducing the amount of allocated memory and computing time. And also the method can be applicable to analysis of the induced current distributions and skin effect in shield. The results of the analysis are presented.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.9 no.2
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• pp.6-11
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• 2010

For the purpose of reducing the energy consumption in the house heating, the various devices have been developed. One of these is to control the flow in the heat pipe and the flow control valve using shape memory alloy(SMA) spring is proposed in our study. The proposed house heating system is to save the gas consumption and the remote control system is designed for the convenience of using the proposed valve. The developed valve consists of SMA spring, disk, return spring, and regulation handle. The regulation handle is for supplying the additional hot water and is controlled by remote-control-motor. In order to design the remote control system, the Zigbee wireless communication protocol is used. The performance of the proposed valve structure is shown through the experimental result.

• Proceedings of the Korean Information Science Society Conference
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• 2011.06a
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• pp.555-558
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• 2011

하드웨어의 발전으로 인하여 한 머신에 장착되는 물리 메모리의 크기가 점차로 커지고 있으며, 가상화 기술과 같은 서버 통합 워크로드가 일반화됨에 따라 개별 응용프로그램의 working set size 또한 증가하고 있다. 하지만 가상주소에 대한 물리주소 변환의 cache인 TLB(Translation Look-aside Buffer)의 커버리지는 물리 메모리 크기가 커짐에 따라 점차 줄어들어 TLB miss가 발생하여 메모리 접근이 느려질 가능성이 더욱 높아지고 있다. 본 논문에서는 계층적 비트맵을 사용하는 TLB 표현 방법을 이용하여 TLB 커버리지를 높이는 하드웨어적인 기법을 제안하고, 이에 적합한 운영체제 기법을 제안한다.

• Proceedings of the KIEE Conference
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• 1987.07b
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• pp.1434-1437
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• 1987

We present a very simple algorithm for reducing the encoding (codebook search) complexity of vector quantization (VQ), exploiting some features of a vector currently being encoded. A proposed VQ of 16 (=$4{\times}4$) vector dimension and 256 codewords shows a slight performance degradation of about 0.1-0.9 dB, however, with only 16 or 32 among 256 codeword searches, i.e., with just 1/16 or 1/8 search complexity compared to a full-search VQ. And the proposed VQ scheme is also compared to and shown to be a bit superior to tree-search VQ with regard to their SNR performance and memory requirement.