• 디지털콘텐츠학회 논문지
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• 제11권1호
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• pp.91-97
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• 2010

비휘발성, 저전력 소모, 안정성 등의 장점을 가진 NAND 플래시 메모리는 고집적화, 대용량화, 저가격화를 통하여 다양한 디지털시스템의 데이터 저장장치로 사용되고 있다. 플래시 메모리의 다양한 분야에서의 응용 확대와 동시에 플래시 메모리의 대용량화는 플래시 메모리의 주소 변환 테이블의 전체 크기를 증가시켜 SRAM에 저장하기에 용량이 부족한 문제점을 발생시킨다. 본 논문에서는 하이브리드 변환 기법 기반의 플래시 메모리 파일 시스템에서 페이지 주소 캐시를 이용한 효율적인 주소 테이블 관리 정책을 제안한다. 제안하는 기법은 다양한 메타 데이터 기반의 전체 테이블의 정보를 맵블록을 이용하여 효율적으로 통합 관리함으로써 높은 성능을 유지할 수 있다. PC 환경에서의 다양한 응용프로그램을 실험한 결과 제안하는 페이지 주소 캐시는 2.5% 이하의 낮은 미스율로 높은 효율성을 유지하며 전체 쓰기 연산 요청에서 평균 33%의 실제 쓰기 연산의 실행으로 전체 쓰기 연산에서 발생하는 오버헤드를 줄여 주었다.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2013년도 제44회 동계 정기학술대회 초록집
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• pp.396-396
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• 2013

The resistive random access memory (ReRAM) has several advantages to apply next generation non-volatile memory device, because of fast switching time, long retentions, and large memory windows. The high mobility of monolayered graphene showed several possibilities for scale down and electrical property enhancement of memory device. In this study, the monolayered graphene grown by chemical vapor deposition was transferred to $SiO_2$ (100 nm)/Si substrate and glass by using PMMA coating method. For formation of metal-oxide nanoparticles, we used a chemical reaction between metal films and polyamic acid layer. The 50-nm thick BPDA-PDA polyamic acid layer was coated on the graphene layer. Through soft baking at $125^{\circ}C$ or 30 min, solvent in polyimide layer was removed. Then, 5-nm-thick indium layer was deposited by using thermal evaporator at room temperature. And then, the second polyimide layer was coated on the indium thin film. After remove solvent and open bottom graphene layer, the samples were annealed at $400^{\circ}C$ or 1 hr by using furnace in $N_2$ ambient. The average diameter and density of nanoparticle were depending on annealing temperature and times. During annealing process, the metal and oxygen ions combined to create $In_2O_3$ nanoparticle in the polyimide layer. The electrical properties of $In_2O_3$ nanoparticle ReRAM such as current-voltage curve, operation speed and retention discussed for applictions of transparent and flexible hybrid ReRAM device.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2007년도 하계학술대회 논문집 Vol.8
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• pp.20-20
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• 2007

Nanowire-based field-effect transistors (FETs) decorated with nanoparticles have been greatly paid attention as nonvolatile memory devices of next generation due to their excellent transportation ability of charge carriers in the channel and outstanding capability of charge trapping in the floating gate. In this work, top-gate single ZnO nanowire-based FETs with and without Au nanoparticles were fabricated and their memory effects were characterized. Using thermal evaporation and rapid thermal annealing processes, Au nanoparticles were formed on an $Al_2O_3$ layer which was semi cylindrically coated on a single ZnO nanowire. The family of $I_{DS}-V_{GS}$ curves for the double sweep of the gate voltage at $V_{DS}$ = 1 V was obtained. The device decorated with nanoparticles shows giant hysterisis loops with ${\Delta}V_{th}$ = 2 V, indicating a significant charge storage effect. Note that the hysterisis loops are clockwise which result from the tunneling of the charge carriers from the nanowire into the nanoparticles. On the other hand, the device without nanoparticles shows a negligible countclockwise hysterisis loop which reveals that the influence of oxide trap charges or mobile ions is negligible. Therefore, the charge storage effect mainly comes from the nanoparticles decorated on the nanowire, which obviously demonstrates that the top-gate single ZnO nanowire-based FETs decorated with Au nanoparticles are the good candidate for the application in the nonvolatile memory devices of next generation.

• Journal of information and communication convergence engineering
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• 제19권4호
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• pp.234-240
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• 2021

As the number of pet dog-related businesses is rising rapidly, there is an increasing need for reliable pet dog health information systems for casual pet owners, especially those caring for older dogs. Our goal is to implement a mobile pre-diagnosis system that can provide a first-hand pre-diagnosis and an appropriate coping strategy when the pet owner observes abnormal symptoms. Our previous attempt, which is based on the fuzzy C-means family in inference, performs well when only relevant symptoms are provided for the query, but this assumption is not realistic. Thus, in this paper, we propose a hybrid inference structure that combines fuzzy association memory and a double-layered fuzzy C-means algorithm to infer the probable disease with robustness, even when noisy symptoms are present in the query provided by the user. In the experiment, it is verified that our proposed system is more robust when noisy (irrelevant) input symptoms are provided and the inferred results (probable diseases) are more cohesive than those generated by the single-phase fuzzy C-means inference engine.

• Advances in nano research
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• 제14권3호
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• pp.261-271
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• 2023

The present study follows three main goals. First, an analytical solution with high accuracy is developed to assess the effects of embedding pre-strained shape memory alloy (SMA) wires on the critical buckling temperatures of rectangular sandwich plates made of soft core and graphite fiber/epoxy (GF/EP) face sheets based on piecewise low-order shear deformation theory (PLSDT) using Brinson's model. As the second goal, this study compares the effects of SMAs on the thermal buckling of sandwich plates with those of carbon nanotubes (CNTs). The glass transition temperature is considered as a limiting factor. For each material, the effective ranges of operating temperature and thickness ratio are determined for real situations. The results indicate that depending on the geometric parameters and thermal conditions, one of the SMAs and CNTs may outperform the other. The third purpose is to study the thermal buckling of sandwich plates with advanced hybrid SMA/CNT/GF/EP composite face sheets. It is shown that in some circumstances, the co-incorporation of SMAs and CNTs leads to an astonishing enhancement in the critical buckling temperatures of sandwich plates.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2008년도 하계종합학술대회
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• pp.649-650
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• 2008

In order to resolve mechanical limit in HDD, recently, the hybrid hard disk combining HDD and a flash memory was launched. In this paper, we propose a simulator for hybrid hard disk which considers redirection, flushing and spin-down function to complement the difference between HDD and hybrid hard disk. The simulator was implemented in linux kernel 2.6.20 by modifying system calls related with file system. The experiment shows that the power consumption of hybrid hard disk is 47% smaller than that of hard disk in laptop PC.

• 한국전산유체공학회:학술대회논문집
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• 한국전산유체공학회 2006년도 PARALLEL CFD 2006
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• pp.275-278
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• 2006

Japan Aerospace Exploration Agency has introduced a new terascale clusterd SMP system as a main compute engine of Numerical Simulator III for aerospace science and engineering research purposes. The system is using Fujitsu PRIMEPOWER HPC2500; it has computing capability of 9.3Tflop/s peak performance and 3.6TB of user memory, with about 1,800 scalar processors for computation. In this paper, we first present the performance evaluation results for aerospace CFD applications with hybrid programming paradigm used at JAXA. Next we propose a performance prediction formula for hybrid codes based on a simple extension of AMhhal's law, and discuss about the predicted and measured performances for some typical hybrid CFD codes.

• Structural Engineering and Mechanics
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• 제42권6호
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• pp.783-797
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• 2012

A new hybrid meta-heuristic optimization algorithm is presented for design of structures. The algorithm is based on the concepts of the charged system search (CSS) and the particle swarm optimization (PSO) algorithms. The CSS is inspired by the Coulomb and Gauss's laws of electrostatics in physics, the governing laws of motion from the Newtonian mechanics, and the PSO is based on the swarm intelligence and utilizes the information of the best fitness historically achieved by the particles (local best) and by the best among all the particles (global best). In the new hybrid algorithm, each agent is affected by local and global best positions stored in the charged memory considering the governing laws of electrical physics. Three different types of structures are optimized as the numerical examples with the new algorithm. Comparison of the results of the hybrid algorithm with those of other meta-heuristic algorithms proves the robustness of the new algorithm.

• 한국컴퓨터정보학회논문지
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• 제18권4호
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• pp.27-34
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• 2013

모바일 로봇은 자신의 임무를 수행하기 위해 탐색 기능을 가지고 있어야 한다. 탐색은 감시 로봇, 구조 로봇, 자원 탐사 로봇 등에 사용될 수 있다. 로봇이 환경을 탐색하기 위해서는 지도와 같은 환경에 대한 정보를 가지고 있어야 한다. 그러나 기존에 많이 사용되는 그리드 지도는 용량이 너무 커서 모바일 로봇에 사용하기 힘들다는 문제를 가지고 있다. 본 논문에서는 저 사양의 모바일 로봇에서 사용할 수 있는 하이브리드 지도를 제안한다. 또한 제안하는 하이브리드 지도를 사용하여 모든 영역을 탐색하는 방법을 제안하고 있다. 제안하는 방법은 로봇의 작업 환경을 현재 처리할 수 있는 영역과 처리 할 수 없는 영역으로 나누고, 나누어진 영역을 탐색하는 동시에 지도를 업데이트하며 영역을 확장해 나간다. 탐색이 완료된 영역은 하이브리드 맵 형태로 저장한다. 생성한 하이브리드 맵을 사용하여 로봇은 장애물이 없는 영역으로 이동 경로를 생성할 수 있다. 실험결과에 따르면 기존 그리드 지도에 비해 약 6%의 메모리만을 사용해 환경 지도를 생성할 수 있었다.

• Journal of Advanced Marine Engineering and Technology
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• 제35권6호
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• pp.842-848
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• 2011

다중통신을 지원하는 하이브리드 통신 제어보드는 저전력의 8-bit 마이크로콘트롤러인 ATxmega128A1으로 설계하였으며, 마이크로콘트롤러는 다중통신을 위한 모뎀과 GPS 모듈 등을 시리얼 인터페이스 하기 위한 8개의 UART 포트가 갖추어져 있으며, 내부에 2K 바이트의 프로그램 매개변수와 프로그램이 동작하는데 필요한 데이터를 저장할 수 있는 EEPROM과 128K 바이트의 플래시 메모리 및 프로그램이 실행되는 8K 바이트의 SRAM으로 구성되어 있다. 항로표지의 원격 관리를 CDMA, TRS, RF 등 하이브리드 통신을 이용하면 개별 통신 방식별로 음영지역이 존재하는 경우에도, 최적의 통신방식을 선택하여 통신을 수행하게 됨으로써, 통신 음영지역의 해소가 가능하다. 또한 통신장치마다 동일한 데이터 프레임을 사용함으로써 데이터의 호환성을 높였다. 실험은 30일 동안 각 부표에서 매 5분마다 데이터를 취득하였으며, 데이터 수신율은 85 % 이상을 보였다.