• 항공우주시스템공학회지
• /
• 제9권2호
• /
• pp.7-12
• /
• 2015

In this paper, we report a non-explosive separation device for a small satellite which utilize a shape memory alloy actuator and spring clamp. In order to increase the preload, the proposed device employs spring clamp that can generate high toque when the shape memory alloy actuator makes the cylinder key unlatch a holding ball effectively. Owing to simple design of separation device configuration, we could obtain good repeatability(up to 30 times activation). Conclusively, we could develop a non-explosive separation device which can reliably activate within 1.2 sec under high preload(up to 300kgf).

• 한국추진공학회지
• /
• 제10권3호
• /
• pp.99-108
• /
• 2006

본 논문은 기존 파이로 부품인 폭발볼트의 기능을 그대로 유지하면서 분리시 발생되는 파편 및 충격파의 악 작용과 파편을 완벽히 제거할 수 있게 형상기억합금(Shape Memory Alloy)을 이용한 분리장치(Fangibolt) 모델의 설계 및 모사에 관한 연구이다. Frangibolt는 기존 폭발볼트에서 사용하는 분리화약을 사용하지 않고 스마트 소재인 형상기억합금의 온도에 따라 변화되는 미세조직에 따른 응력생성을 이용하여 파이로 장치를 분리시키는 Non Pyrotechnic 장치로써, 실제 Frangibolt노치부에 생성되는 응력의 분포 및 분리거동을 해석함으로써 Frangibolt 설계에 필요한 인자를 파악할 수 있었다. 또한 볼트 설계방법의 최적화를 제시함으로써 향후 다른 종류의 SMA을 이용한분리장치 설계 및 해석 모델에 기초자료를 제공할 수 있을 것이다.

• 한국전기전자재료학회:학술대회논문집
• /
• 한국전기전자재료학회 2008년도 추계학술대회 논문집 Vol.21
• /
• pp.19-19
• /
• 2008

We investigated the programmable memory characteristics of nanoparticle-based memory devices based on the elementary metal nanoparticles (Co and Au) and their binary mixture synthesized by a micellar route to ordered arrays of metal nanoparticles as charge trapping layers. According to the metal nanoparticle species quite different programming/erasing efficiencies were observed, resulting in the tunable memory characteristics at the same programming/erasing bias conditions. This finding will be a good implication for further device scaling and novel device applications since most processes are based on the conventional semiconductor processes.

• 한국전기전자재료학회논문지
• /
• 제19권10호
• /
• pp.918-922
• /
• 2006

Chalcogenide Phase change memory has the high performance necessary for next-generation memory, because it is a nonvolatile memory with high programming speed, low programming voltage, high sensing margin, low power consumption and long cycle duration. To minimize the power consumption and the program voltage, the new composition material which shows the better phase-change properties than conventional $Ge_2Sb_2Te_5$ device has to be needed by accurate material engineering. In the present work, we investigate the basic thermal and the electrical properties due to phase-change compared with chalcogenide-based new composition $Ge_1Se_1Te_2$ material thin film and convetional $Ge_2Sb_2Te_5$ PRAM thin film. The fabricated new composition $Ge_1Se_1Te_2$ thin film exhibited a successful switching between an amorphous and a crystalline phase by applying a 950 ns -6.2 V set pulse and a 90 ns -8.2 V reset pulse. It is expected that the new composition $Ge_1Se_1Te_2$ material thin film device will be possible to applicable to overcome the Set/Reset problem for the nonvolatile memory device element of PRAM instead of conventional $Ge_2Sb_2Te_5$ device.

• JSTS:Journal of Semiconductor Technology and Science
• /
• 제15권1호
• /
• pp.68-76
• /
• 2015

Phase-change memory (PCM) is a promising technology that is anticipated to be used in the memory hierarchy of future computer systems. However, its access time is relatively slower than DRAM and it has limited endurance cycle. Due to this reason, PCM is being considered as a high-speed storage medium (like swap device) or long-latency memory. In this paper, we adopt PCM as a virtual memory swap device and present a new page replacement policy that considers the characteristics of PCM. Specifically, we aim to reduce the write traffic to PCM by considering the dirtiness of pages when making a replacement decision. The proposed replacement policy tracks the dirtiness of a page at the granularity of a sub-page and replaces the least dirty page among pages not recently used. Experimental results with various workloads show that the proposed policy reduces the amount of data written to PCM by 22.9% on average and up to 73.7% compared to CLOCK. It also extends the lifespan of PCM by 49.0% and reduces the energy consumption of PCM by 3.0% on average.

• 정보과학회 컴퓨팅의 실제 논문지
• /
• 제23권3호
• /
• pp.165-170
• /
• 2017

GPGPU의 높은 연산 처리 능력을 활용하여 길고 복잡한 계산을 하려는 시도가 많이 있다. GPGPU 프로그램의 특성상 host와 device 사이에 메모리 복사가 필요하다. 해당 메모리 복사 latency가 길 경우 프로그램의 성능에 많은 영향을 준다. 그래서 GPGPU를 활용한 프로그래밍은 최적화에 따른 성능 차이가 크다. 여러 개의 GPGPU 프로그램을 동시에 실행시키면 메모리 복사와 GPGPU 컴퓨팅이 중첩이 되어 메모리 복사 latency hiding 효과를 기대할 수 있다. 이 논문에서는 메모리 복사 latency hiding을 분석한다. 또 메모리 복사의 성능을 높이기 위해 pinned memory를 사용했을 경우의 제약 조건에 따른 성능 예측 모델링 및 알고리즘을 제안하고 이를 바탕으로 실행할 워크로드를 선택하면 41%의 성능 향상을 보인다.

• 대한전자공학회:학술대회논문집
• /
• 대한전자공학회 2002년도 ITC-CSCC -2
• /
• pp.932-935
• /
• 2002

In this paper, we introduce new FTL(Flash Translation Layer) driver algorithm that tolerate the power off errors. FTL driver is the software that provide the block device interface to the upper layer software such as file systems or application programs that using the flash memory as a block device interfaced storage. Usually, the flash memory is used as the storage devices of the mobile system due to its low power consumption and small form factor. In mobile system, the state of the power supplement is not stable, because it using the small sized battery that has limited capacity. So, a sudden power off failure can be occurred when we read or write the data on the flash memory. During the write operation, power off failure may introduce the incomplete write operation. Incomplete write operation denotes the inconsistency of the data in flash memory. To provide the stable storage facility with flash memory in mobile system, FTL should provide the fault tolerance against the power off failure. SSR (Simple Sector Remapper) is a fault tolerant FTL driver that provides block device interface and also provides tolerance against power off errors.

• 예술인문사회 융합 멀티미디어 논문지
• /
• 제9권3호
• /
• pp.747-756
• /
• 2019

통역을 학습하는 학생들은 수업 외에도 추가적인 학습 및 훈련을 수행한다. 동시통역 및 순차통역에서 두 언어의 구조가 다르기 때문에 통역가는 발표 내용을 빠르게 기억해야 한다. 단기 기억 향상을 위해서 통역을 학습하는 학생들은 메모리 훈련을 수행한다. 메모리 훈련은 파트너가 필요하기 때문에 학습 효율성이 저하되고 자가 학습이 불가능하다. 이를 해결하기 위해서 컴퓨터 기반의 단기 기억 훈련 시스템이 제안되었다. 지문 내 단어를 특수문자로 변경함으로써 학생들이 파트너 없이도 자가 학습이 가능하다. 하지만 컴퓨터는 휴대성이 떨어지기 때문에 외부에서는 학습 능률이 저하된다. 제거되는 단어보다 키워드로 제공하는 단어의 수가 더 많아서 학습 난이도가 저하된다. 이를 해결하기 위해서, 본 논문에서는 스마트 단말 기반의 문장구역 훈련 시스템을 제안하였다. 스마트 단말은 휴대성이 높아 학습의 제한이 없어 효율이 증가한다. 제안하는 훈련 시스템에서는 삭제되는 단어수가 키워드보다 더 많도록 하여 학습 난이도가 증가한다. 제안한 훈련 시스템을 구현하고 기능을 검증하였다.

• 한국진공학회:학술대회논문집
• /
• 한국진공학회 2011년도 제40회 동계학술대회 초록집
• /
• pp.118-118
• /
• 2011

The Nano-Floating Gate Memory(NFGM) devices with ZnO:Cu thin film embedded in Al2O3 and AlOx-SAOL were fabricated and the electrical characteristics were evaluated. To further improve the scaling and to increase the program/erase speed, the high-k dielectric with a large barrier height such as Al2O3 can also act alternatively as a blocking layer for high-speed flash memory device application. The Al2O3 layer and AlOx-SAOL were deposited by MLD system and ZnO:Cu films were deposited by ALD system. The tunneling layer which is consisted of AlOx-SAOL were sequentially deposited at $100^{\circ}C$. The floating gate is consisted of ZnO films, which are doped with copper. The floating gate of ZnO:Cu films was used for charge trap. The same as tunneling layer, floating gate were sequentially deposited at $100^{\circ}C$. By using ALD process, we could control the proportion of Cu doping in charge trap layer and observe the memory characteristic of Cu doping ratio. Also, we could control and observe the memory property which is followed by tunneling layer thickness. The thickness of ZnO:Cu films was measured by Transmission Electron Microscopy. XPS analysis was performed to determine the composition of the ZnO:Cu film deposited by ALD process. A significant threshold voltage shift of fabricated floating gate memory devices was obtained due to the charging effects of ZnO:Cu films and the memory windows was about 13V. The feasibility of ZnO:Cu films deposited between Al2O3 and AlOx-SAOL for NFGM device application was also showed. We applied our ZnO:Cu memory to thin film transistor and evaluate the electrical property. The structure of our memory thin film transistor is consisted of all organic-inorganic hybrid structure. Then, we expect that our film could be applied to high-performance flexible device.----못찾겠음......

• 한국진공학회:학술대회논문집
• /
• 한국진공학회 2015년도 제49회 하계 정기학술대회 초록집
• /
• pp.192.1-192.1
• /
• 2015

We demonstrated the nonvolatile memory functionality of nano-crystalline silicon (nc-Si) and InGaZnOxide (IGZO) thin film transistors (TFTs) using mobile protons that are generated by very short time hydrogen neutral beam (H-NB) treatment in gate insulator (SiO2). The whole memory fabrication process kept under $50^{\circ}C$ (except SiO2 deposition process; $300^{\circ}C$). These devices exhibited reproducible hysteresis, reversible switching, and nonvolatile memory behaviors in comparison with those of the conventional FET devices. We also executed hydrogen treatment in order to figure out the difference of mobile proton generation between PECVD and H-NB CVD that we modified. Our study will further provide a vision of creating memory functionality and incorporating proton-based storage elements onto a probability of next generation flexible memorable electronics such as low power consumption flexible display panel.