• Proceedings of the Korean Information Science Society Conference
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• 1999.10c
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• pp.6-8
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• 1999

세그먼트 디렉토리는 CC-NUMA (Cache Coherent Non-Uniform Memory Access)시스템의 전체 벡터와 포인터의 장점만을 가지는 새로운 형태의 디렉토리 요소이다. 포인터가 하나의 프로세서 위치만을 가리키는데 비해, 세그먼트 디렉토리는 복수 개이 프로세서들을 한 번에 가리킬 수 있으면서, 포인터처럼 작은 단위로 사용가능하다. 본 논문에서는 세그먼트 디렉토리를 제한 디렉토리 방법들에 적용하여 디렉토리 넘침의 횟수를 줄인다. 기존의 방법들이 디렉토리 넘침 후의 효율적인 캐쉬 일관성 유지 기법을 제시했던 것에 비해, 세그먼트 디렉토리는 디렉토리 넘침 자체를 제거하는 최초의 시도이다. 디렉토리 넘침의 제거로 CC-NUMA 시스템 대역폭 요구량이 줄어들고, 프로그램 수행이 가속되며, 디렉토리 제어기 점유가 대폭 감소된다. Tango-Lite를 사용한 실행 구동 시뮬레이션을 통하여 세그먼트 디렉토리가 약 80%까지의 디렉토리 넘침을 제거한 것을 확인하였고, 이에 따르는 시스템 성능 향상을 분석하였다.

• 정보저장시스템학회:학술대회논문집
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• 2005.10a
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• pp.83-87
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• 2005

Data storage related with writing and retrieving requires high storage capacity, fast transfer rate and less access time in. Today any data storage system can not satisfy these conditions, but holographic data storage system can perform faster data transfer rate because it is a page oriented memory system using volume hologram in writing and retrieving data. System architecture without mechanical actuating pare is possible, so fast data transfer rate and high storage capacity about 1Tb/cm3 can be realized. In this paper, to correct errors of binary data stored in holographic digital data storage system, find cluster centers using clustering algorithm and reduce intensities of pixels around centers. We archive the procedure by two algorithms of C-mean and subtractive clustering, and compare the results of the two algorithms. By using proper clustering algorithm, the intensity profile of data page will be uniform and the better data storage system can be realized.

• Transactions of the Society of Information Storage Systems
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• v.6 no.1
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• pp.31-36
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• 2010

Data storage related with writing and retrieving requires high storage capacity, fast transfer rate and less access time. Today any data storage system cannot satisfy these conditions, however holographic data storage system can perform faster data transfer rate because it is a page oriented memory system using volume hologram in writing and retrieving data. System can be constructed without mechanical actuating part so fast data transfer rate and high storage capacity about 1Tb/cm3 can be realized. In this research, to correct errors of binary data stored in holographic data storage system, a new method for reduction errors is suggested. First, find cluster centers using subtractive clustering algorithm then reduce intensities of pixels around cluster centers. By using this error reduction method following results are obtained ; the effect of Inter Pixel Interference noise in the holographic data storage system is decreased and the intensity profile of data page becomes uniform therefore the better data storage system can be constructed.

• Journal of Magnetics
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• v.21 no.4
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• pp.491-495
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• 2016

We developed an embedded Object-Oriented Micromagnetic Frame (OOMMF) script schemes for more flexible simulations for complex and dynamic mircomagnetic behaviors. The OOMMF can be called from any kind of softwares by system calls, and we can interact with OOMMF by updating the input files for next step from the output files of the previous step of OOMMF. In our scheme, we set initial inputs for OOMMF simulation first, and run OOMMF for ${\Delta}t$ by system calls from any kind of control programs. After executing the OOMMF during ${\Delta}t$, we can obtain magnetization configuration file, and we adjust input parameters, and call OOMMF again for another ${\Delta}t$ running. We showed one example by using scripting embedded OOMMF scheme, tunneling magneto-resistance dependent switching time. We showed the simulation of tunneling magneto-resistance dependent switching process with non-uniform current density using the proposed framework as an example.

• Proceedings of the KIEE Conference
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• 2005.11a
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• pp.87-89
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• 2005

$Bi_{3.25}Y_{0.75}Ti_{3}O_{12}$[BYT] ferroelectric thin films were deposited by RF-Sputtering method on the $Pt/Ti/SiO_2/Si$. We investigated the effects of processing condition (especially post-annealing) on the structural and ferroelectric properties of the BYT thin films. Increasing the annealing temperature, the peak intensity of (117) increased and c-axis orientation decreased. The BYT thin films crystallized well at $600^{\circ}C$ for 30min. No secondary phases observed in the XRD pattern. At annealing temperature of $700^{\circ}C$, the thin films had no cracks and the grain was uniform. The calculated lattice constants of BYT thin films were a=0.539nm, b=0.536nm, c=3.288nm. The remnant polarization of the $Bi_{3.25}Y_{0.75}Ti_{3}O_{12}$ capacitor reached $1.8uC/cm^2$ at an applied field about 400kV/cm. The BYT thin films can be used as capacitors in Ferroelectric Random Access Memory device.

• 정보저장시스템학회:학술대회논문집
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• 2005.10a
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• pp.44-46
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• 2005

Data storage related with writing and retrieving requires high storage capacity, fast transfer rate and less access time. Today any data storage system cannot satisfy these conditions, however holographic data storage system can perform faster data transfer rate because it is a page oriented memory system using volume hologram in writing and retrieving data. System can be constructed without mechanical actuating part therefore fast data transfer rate and high storage capacity about $1Tb/cm^3$ can be realized. In this paper, to reduce errors of binary data stored in holographic data storage system, a new method for bit error reduction is suggested. We proposal Algorithm use The Extended Kalman filter. The Kalman filter reduce measurement noise. Therefore, By using this error reduction method following results are obtained; the effect of measurement nois of Pixel is decreased and the intensity profile of data page becomes uniform therefore the better data storage system can be constructed.

• 정보저장시스템학회:학술대회논문집
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• 2005.10a
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• pp.129-133
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• 2005

Data storage related with writing and retrieving requires high storage capacity, fast transfer rate and less access time. Today any data storage system cannot satisfy these conditions, however holographic data storage system can perform faster data transfer rate because it is a page oriented memory system using volume hologram in writing and retrieving data. System can be constructed without mechanical actuating part therefore fast data transfer rate and high storage capacity about $1Tb/cm^3$ can be realized. In this paper, to reduce errors of binary data stored in holographic data storage system, a new method for bit error reduction is suggested. First, find cluster centers using subtractive clustering algorithm then reduce intensities of pixels around cluster centers and fuzzy rules. Therefore, By using this error reduction method following results are obtained ; the effect of Inter Pixel Interference noise is decreased and the intensity profile of data page becomes uniform therefore the better data storage system can be constructed.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.27 no.8
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• pp.491-496
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• 2014

The resistive switching characteristics of resistive random access memory (ReRAM) based on amorphous $Ge_{0.5}Se_{0.5}$ thin films have been demonstrated by using Ti/Ag nanocrystals/$Ge_{0.5}Se_{0.5}$/Pt structure. Ag nanocrystals (Ag NCs) were spread on the amorphous $Ge_{0.5}Se_{0.5}$ thin film and they played the role of metal ions source. As a result, comparing the conventional Ag/$Ge_{0.5}Se_{0.5}$/Pt structure, this Ti/Ag NCs/$Ge_{0.5}Se_{0.5}$/Pt ReRAM device exhibits the highly uniform bipolar resistive switching (BRS) characteristics, such as the operating voltages, and the resistance values. At the same time, a stable DC endurance(> 100 cycles), and the excellent data retention (> $10^4$ sec) properties were found from the Ti/Ag NCs/$Ge_{0.5}Se_{0.5}$/Pt structured ReRAM device.

• Journal of KIISE:Computer Systems and Theory
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• v.31 no.11
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• pp.658-672
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• 2004

Multimedia applications are required to process the huge amount of data at high speed in real time. The memory reference instructions such as loads and stores are the main factor which limits the high speed execution of processor. To enhance the memory reference speed, cache prefetch schemes are used so as to reduce the cache miss ratio and the total execution time by previously fetching data into cache that is expected to be referenced in the future. In this study, we present an advanced data cache prefetching scheme that improves the conventional RPT (reference prediction table) based scheme. We considers the cache line size in calculation of the address stride referenced by the same instruction, and enhances the prefetching algorithm so that the effect of prefetching could be maintained even if an irregular address stride is inserted into the series of uniform strides. According to experiment results on multimedia benchmark programs, the cache miss ratio has been improved 29% in average compared to the conventional RPT scheme while the bus usage has increased relatively small amount (0.03%).

• Journal of the Korea Institute of Information and Communication Engineering
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• v.26 no.10
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• pp.1432-1440
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• 2022

Recently, as Virtual Desktop Infrastructure(VDI) is widely used not only in office work environments but also in workloads that use high-spec multi-core-based applications, the requirements for real-time and stability of VDI are increasing. Accordingly, the display protocol used for remote access in VDI and performance optimization of virtual machines have also become more important. In this paper, we propose two ways to configure desktop virtualization for multi-core-based application operation. First, we propose a codec configuration of a display protocol with optimal performance in a high load situation due to multi-processing. Second, we propose a virtual CPU scheduling optimization method to reduce scheduling delay in case of CPU contention between virtual machines. As a result of the test, it was confirmed that the H.264 codec of Blast Extreme showed the best and stable frame, and the scheduling performance of the virtual CPU was improved through scheduling optimization.