• 한국통신학회논문지
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• 제29권4B호
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• pp.397-402
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• 2004

본 논문에서는 파일 전송 시 발생하는 메모리 복사(memo교 copy)와 문맥 교환(context switch)을 최소화하여 시스템의 성능(performance)을 향상시킬 수 있는 네트워크 시스템 호출에 관한 연구를 수행하였다. 기존 파일 전송 기법에서 사용자가 하나의 패킷을 전송할 때, 사용자와 커널(Kernel) 공간 사이에서의 메모리 복사가 2회에 걸쳐 수행된다. 이러한 사용자와 커널 공간 사이에서 이루어지는 메모리 복사는 데이터 전송에 소요되는 시간을 증가시키고, 시스템의 성능에 좋지 않은 영향을 준다. 본 논문은 이러한 문제점들을 해결하기 위하여 필요한 경우 사용자와 커널 사이에서의 메모리 복사를 수행하지 않고, 데이터가 커널 공간 내에서 송수신될 수 있는 새로운 알고리즘을 제시하였다. 또한 실제의 시스템에서 제안된 알고리즘의 성능을 분석하기 위하여 리눅스 커널 버전 2.6.0의 소스 코드를 수정하였고, 새로운 네트워크 시스템 호출을 구현하였다. 성능 측정 결과, 본 연구에서 제안한 파일 전송 방식이 기존의 파일 전승 방식에 비하여 짧은 파일 전송 시간을 보여주었다.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2001년도 추계학술대회 논문집 Vol.14 No.1
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• pp.17-20
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• 2001

Nonvolatile semiconductor memory devices with reoxidized nitrided oxide(RONO) gate dielectrics were fabricated, and nitrogen distribution and bonding species which contribute to memory characteristics were analyzed. Also, memory characteristics of devices depending on the anneal temperatures were investigated. The devices were fabricated by retrograde twin well CMOS processes with $0.35{\mu}m$ Nonvolatile semiconductor memory devices with reoxidized nitrided oxide(RONO) gate dielectric were fabricated, and nitrogen distribution and bonding species which contributing memory characteristics were analyzed. Also, memory characteristics of devices according to anneal temperatures were investigated. The devices were fabricated by $0.35{\mu}m$ retrograde twin well CMOS processes. The processes could be simple by in-situ process of nitridation anneal and reoxidation. The nitrogen distribution and bonding state of gate dielectric were investigated by Dynamic Secondary Ion Mass Spectrometry(D-SIMS), Time-of-Flight Secondary Ion Mass Spectrometry(ToF-SIMS), and X-ray Photoelectron Spectroscopy(XPS). Nitrogen concentrations are proportional to nitridation anneal temperatures and the more time was required to form the same reoxidized layer thickness. ToF-SIMS results show that SiON species are detected at the initial oxide interface and $Si_{2}NO$ species near the new $Si-SiO_{2}$ interface that formed after reoxidation. As the anneal temperatures increased, the device showed worse retention and degradation properties. These could be said that nitrogen concentration near initial interface is limited to a certain quantity, so excess nitrogen are redistributed near the $Si-SiO_{2}$ interface and contributed to electron trap generation.

• 한국지능시스템학회논문지
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• 제20권6호
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• pp.761-767
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• 2010

낸드 플래시 메모리는 블록에 새로운 데이터를 쓰고자 할 때 삭제 연산이 선행되어야 하며 일정 횟수 이상 지움 연산이 반복된 블록은 더 이상 사용이 불가능하다. 데이터의 갱신이 빈번한 핫 데이터는 블록을 빠르게 사용 불가능한 상태에 도달하게 만들 수 있고 이로써 낸드 플래시 메모리의 용량은 시간이 지남에 따라 감소할 수 있다. 본 논문에서는 데이터의 접근 패턴을 고려해 핫 데이터와 콜드 데이터를 분류하는 알고리즘을 제시한다. 이렇게 분류된 데이터 정보를 이용해 삭제 횟수가 많은 블록에 갱신 확률이 적은 콜드 데이터를, 삭제 횟수가 상대적으로 적은 블록에 갱신 확률이 높은 핫 데이터를 맵핑한다. 입력 데이터 패턴을 이용한 핫/콜드 데이터 분류 기법이 기존의 분류 기법을 사용했을 때보다 플래시 메모리의 블록 사용이 균일한 것을 실험을 통해 확인하였다.

• 한국항행학회논문지
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• 제24권4호
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• pp.305-313
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• 2020

원격측정 시스템은 비행체의 상태 정보 데이터를 획득하여 지상 수신소로 전송하는 시스템이다. PCM 엔코더는 획득한 상태 정보 데이터를 이용하여 프레임을 생성하기 위해 채널 정보를 저장할 메모리가 필요하다. 대형 비행체의 경우 각 부위의 센서 및 시스템이 증가함에 따라 많은 데이터를 계측해야 하므로 더 큰 용량의 메모리를 필요로 한다. 그러나 한정된 메모리에서 모든 채널 정보를 저장하기에는 어려움이 있다. 따라서 본 논문에서는 FPGA 내부 ROM의 한정된 메모리에서 중복되는 채널 정보는 메모리에 한번만 할당하고, 마이너 프레임마다 다른 정보를 가지는 서브콤의 채널 정보는 서브콤 배수만큼 메모리에 할당하는 PCM 엔코더 구조를 제시하고 구현하였다. 이는 중복으로 할당되는 채널 정보를 최소화하여 효율적으로 메모리를 관리할 수 있다. 또한 다양한 계측 주기의 채널을 구성한 시뮬레이션을 통해 제시한 PCM 엔코더의 동작을 검증하였다.

• 한국의류학회지
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• 제36권4호
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• pp.382-390
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• 2012

This study shows the optimum attachment of Two-Way Shape Memory Alloy (TWSMA) springs onto thermal liner and its sewing method for the mass production of fire fighter's intelligent turnout gear. SMA springs were attached to the fabric by four different methods and stitched by two different shapes (square and wave). The durability of the attached springs was tested by laundering up to 50 cycles. Examined were whether the springs would remain attached to the fabric after repeated laundering, the shape memory effect and reaction of the springs, and the anti-corrosiveness of the springs. A Human-Clothing-Environment simulator evaluated thermal insulation according to attachment methods, air layer volume, and stitch types. The findings showed that silicon attached springs remained intact after repeated laundering; in addition, repeated laundering did not influence the responsiveness and anti-corrosiveness of SMAs. Air volume had positive relations with the insulation. Attachment methods or stitch methods had limited impact on the thermal insulation. As a result, a wave type stitch with silicone attachment was suggested as the optimum method to attach the SMA springs onto the intelligent turnout gear for fire fighters.

• 전자공학회논문지B
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• 제33B권5호
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• pp.41-51
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• 1996

In this paper, anew parallel processing system based on a cluster architecture which provides scalability of a parallel processing system while maintains shared memory multiprocessor characteristics is proposed. In recent days low cost, high performnce microprocessors have led to construction of large scale parallel processing systems. Such parallel processing systems provides large scalability but are mainly used for scientific applications which have large data parallelism. A shared memory multiprocessor system like TICOM is currently used as aserver for the commercial application, however, the shared memory multiprocessor system is known to have very limited scalability. The proposed architecture can support scalability and performance of the parallel processing system while it provides adaptability for the commerical application, hence it can overcome the limitation of the shared memory multiprocessor. The architecture and characteristics of the proposed system shall be described. A proprietary hierarchical crsossbar network is designed for this system, of which the protocol, routing and switching technique and the signal transfer technique are optimized for the proposed architecture. The design trade-offs for the network are described in this paper and with simulation usihng the SES/workbench, it is explored that the network fits to the proposed architecture.

• 한국군사과학기술학회지
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• 제14권5호
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• pp.842-849
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• 2011

The transponder simulator designed to simulate the transponder of military satellite communication systems in the geostationary orbit is required to have time delay function, because of 250 ms delay time, when a radio wave transmits the distance of 36,000 km in free space. But, it is very difficult to develop 250 ms time delay device in the transponder simulator of 100 MHz bandwidth, due to unstable operation of FPGA, loss of memory data for the high speed rate signal processing. Up to date, bandwidth of the time delay device is limited to 45 MHz bandwidth. To solve this problem, we propose the new time delay techniques up to 100 MHz bandwidth without data loss. Proposed techniques are the low speed down scaling and high speed up scaling methods to read and write the external memory, and the matrix structure design of FPGA memory to treat data as high speed rate. We developed the satellite link simulator in 100 MHz bandwidth using the proposed new time delay techniques, implemented to the transponder simulator and verified the function of 265 ms time delay device in 100 MHz bandwidth.

• 한국강구조학회 논문집
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• 제16권1호통권68호
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• pp.145-153
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• 2004

기존교량의 내진성능개선 및 신설교량의 지진보호에 납-고무 베어링은 좋은 효과를 보여주고 있다. 그러나 납-고무 베어링은 사용상에 있어 문제점이 있으며, 이를 개선하기 위하여 형상기억합금(shape memory alloy)을 이용한 면진장치를 본 연구에서 제시하였다. 3경간 연속 고속도로 강교량의 지진해석을 통하여 납-고무베어링과 고무베어링 및 형상기억합금 와이어와의 조합 면진장치의 지진거동을 비교하였다. 해석결과 형상기억합금 와이어+고무베어링 시스템이 납-고무베어링과 거의 유사한 거동을 보여주었으며, 특히 제시된 면진장치는 상대변위의 제어 및 잔류변형에 있어 기존의 납-고무 베어링에 비해 성능이 우수했다.

• Advances in Traditional Medicine
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• 제7권2호
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• pp.182-190
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• 2007

Alzheimer's disease is a neurodegenerative disorder associated with a decline in cognitive abilities. Dementia is one of the aged related mental problems and a characteristic symptom of Alzheimer's disease. Nootropic agents like piracetam and cholinesterase inhibitors like $Donepezil^{\circledR}$ are used in situations where there is organic disorder in learning abilities, but the resulting side-effects associated with these agents have limited their utility. Foeniculum (F.) vulgare Linn. is widely used in Indian traditional systems of medicines and also as a house remedy for nervous debility. The present work was undertaken to assess the potential of F. vulgare as a nootropic and anti-cholinesterase agent in mice. Exteroceptive behavioral models such as Elevated plus maze and Passive avoidance paradigm were employed to assess short term and long term memory in mice. To delineate the possible mechanism through which F. vulgare elicits the anti-amnesic effects, its influence on central cholinergic activity was studied by estimating the whole brain acetylcholinesterase activity. Pretreatment of methanolic extract of fruits of F. vulgare Linn. for 8 successive days, ameliorated the amnesic effect of scopolamine (0.4 mg/kg) and aging induced memory deficits in mice. F. vulgare extract significantly decreased transfer latencies of young mice and aged mice, increased step down latency and exhibited significant anti-acetyl cholinesterase effects, when compared to piracetam, scopolamine and control groups of mice. F. vulgare might prove to be a useful memory restorative agent in the treatment of dementia seen in the elderly.

• 한국전기전자재료학회논문지
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• 제15권7호
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• pp.576-582
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• 2002

Nonvolatile semiconductor memory devices with reoxidized nitrided oxide(RONO) gate dielectrics were fabricated, and nitrogen distribution and bonding species which contribute to memory characteristics were analyzed. Also, memory characteristics of devices depending on the anneal temperatures were investigated. The devices were fabricated by retrograde twin well CMOS processes with $0.35\mu m$ design rule. The processes could be simple by in-situ process in growing dielectric. The nitrogen distribution and bonding states of gate dielectrics were investigated by Dynamic Secondary Ion Mass Spectrometry(D-SIMS), Time-of-Flight Secondary Ion Mass Spectrometry(ToF-SIMS), and X-ray Photoelectron Spectroscopy(XPS). As the nitridation temperature increased, nitrogen concentration increased linearly, and more time was required to form the same reoxidized layer thickness. ToF-SIMS results showed that SiON species were detected at the initial oxide interface which had formed after NO annealing and $Si_2NO$ species within the reoxidized layer formed after reoxidation. As the anneal temperatures increased, the device showed worse retention and degradation properties. It could be said that nitrogen concentration near initial interface is limited to a certain quantity, so the excess nitrogen is redistributed within reoxidized layer and contribute to electron trap generation.