• Journal of the Korean Institute of Telematics and Electronics
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• v.26 no.5
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• pp.79-84
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• 1989

Optical implementation of a quadratic associative memory model of neural networks is reported. Weighted $N^3$ interconnections between neurons are realized with an optical matrix-vector multiplier and interconnection holograms.

• Korean Journal of Biological Psychiatry
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• v.13 no.2
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• pp.117-120
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• 2006

Localized amnesia is characterized by a failure to recall events that occurred during a circumscribed period of time. Localized amnesia is the most common type of dissociative amnesia. It is assumed that this is a disorder of memory retrieval. Recent neuroimaing studies reported that posterior cingulate cortex may play a important role in memory(autobiographical) retrieval. The authors reported a case of localized amnesia with mass on left posterior cingulate cortex.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2001.04a
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• pp.687-691
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• 2001

Al alloy matrix composite with TiNi shape memory fiber as reinforcement has been fabricated by hot pressing to investigate mechanical properties. The stress-strain behavior of the composites was evaluated at temperatures between 363K and room temperature as a function of pre-strain by using experimental and finite element analysis, and both cases showed that the tensile stress at 363K was higher than that of the room temperature. Especially, the tensile stress of this composite increases with increasing the amount of pre-strain, and it also depends on the volume fraction of fiber and heat treatment. The smartness of the composite is given due to the shape memory effect of the TiNi fiber which generates compressive residual stress in the matrix material when heated after being pre-strained.

• Korean Journal of Adult Nursing
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• v.18 no.3
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• pp.468-478
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• 2006

Purpose: The purpose of this study were to find out the degree of memory decline and to confirm its correlated factors in old adults. Method: The subjects consisted of 68 old adults over the age 65 who living in Busan. Data were collected by the interview method, using a structured questionnaire and the testing method on the memory performance. Results: The old adults' memory performances declined in tasks of immediately word recall, delayed word recall, and face recognition and increased slightly in word recognition over 2 years. However, there was only significant difference in delayed word recall task. The significant variables to predict memory decline were age, literacy, depression, locus, and strategy. Conclusion: The memory decline of old adults wasn't more serious problem than the perceived one. There needs to be some intervention programs to prevent memory decline for the elderly.

• Annual Conference on Human and Language Technology
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• 1994.11a
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• pp.113-118
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• 1994

한국어 정보처리를 효율적으로 수행하기 위해서는 단어의 검색시간을 최소화하여야 한다. 그러나 기존의 방법들은 단어의 삽입과 삭제가 불가능하거나 검색시간이 길다는 단점을 가지고 있다. 본 논문에서는 탐식시간을 최소화하기 위해서 이중 배열을 가지는 이중 트라이를 이용하여 음절 및 자소단위의 검색방법에 관하여 논의한다. 검색시간에 있어서는 음절단위의 방법이 자소단위의 방법보다 빠르지만 기억장소는 자소단위의 방법이 음절단위의 방법보다 효율적이다. 자소단위의 방법에서 하나의 트라이를 여러개로 분할하여 저장함으로써 기억장소를 절반으로 줄일 수 있어 기억장소를 보다 효율적으로 이용할 수 있다.

• Annual Conference on Human and Language Technology
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• 1994.11a
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• pp.207-210
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• 1994

한글 전자사전은 많은 양의 데이타를 저장할 수 있어야 하며, 빠른 검색 속도를 제공해야 한다. 기존의 트라이는 공통접두사만을 압축하기 때문에 사전의 크기가 방대하다는 단점이 있다. 본 논문에서는 DAWG(Directed Acyclic Word Graph)를 이용하여 공통접미사까지 압축하였고, 검색과 기억장소의 효율을 위하여, 링크드리스트 구조의 DAWG를 유형별 배열 구조로 바꾸었다. 전국의 각 학교 이름들을 대상으로 실험한 결과, 본 논문에서 제안한 DAWG를 이용한 배열 구조의 사전은 트라이와 비교하여 볼 때, 검색 연산의 성능은 동일하게 유지하면서 기억 장소의 효율과 압축율에서 효과적이었다. 또한, 트라이보다 주기억장치와 보조기억장치와의 블록 입출력횟수를 줄임으로써 전체 검색 시간을 낮출 수 있었다.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.22 no.7
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• pp.669-674
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• 2011

In this paper, a method for reduction of spurious signal in Digital RF Memory(DRFM) is proposed. Spurious response is a major performance issue of DRFM. This method is based on mixing a random phase LO signal into input IF signal and sampling it. The random phase LO signal is generated by high speed phase shifting characteristic of Direct Digital Synthesizer(DDS). Through this technique, we achieved an enhancement of 5~10 dB of spurious response.

• Proceedings of the Korea Institutes of Information Security and Cryptology Conference
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• 2001.11a
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• pp.71-74
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• 2001

패스워드는 가장 광범위한 인증의 수단으로 사용되어지고 있다. 안전성 측면에서는 패스워드의 길이가 길수록 안전하고 Dictionary Attack 등에 강할 것이다. 그러나, 긴 패스워드를 기억하고 있는 것은 어려운 일이다. 또한, 하나 이상의 패스워드가 필요한 경우 현실적으로 긴 패스워드를 모두 기억하고 있는 것은 현실적으로 불가능, 혹은 어려운 일이다. 또한, 인터넷 보안을 위한 비밀성을 보장하기 위해서 블록암호알고리즘을 사용하고 있다. 공개키보다 빠른 연산속도를 가지고 있고, 키 분배의 문제를 해결한다면 안전한 인터넷을 이용할 수 있을 것이다. 따라서, 본 논문에서는 짧은 패스워드를 이용하여 키 분배를 이루는 프로토콜을 제안한다. 또한 공격에 강한 알고리즘을 위해서 본 논문에서는 Signcryption 알고리즘을 이용하여 짧은 패스워드를 가지고 키분배를 하고, Dictionary Attack에 강한 알고리즘을 설계한다.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.31 no.3 s.258
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• pp.373-379
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• 2007

In this study, we observe the application of shape memory alloy(SMA) into smart structures for repeatable actuation, because SMA changes its material properties and characteristics progressively under cyclic loading conditions and finally reaches stable path(state) after a certain number of stress/temperature loading-unloading cycles, so called 'training'. In this paper, SMA wires that have been in a stable state through the training are used. Stress-strain curve of the SMA wire at different temperature levels are measured. In addition, we observe other important effects such as the rate effect according to strain rates for rapid actuation response. The current work presents the experimental test using SMA wire after training completion by mechanical cycling. Through these tests, we measure the characteristics of SMA. With the estimated SMA properties and effects, we compare the experimental results with the simulation results based on the SMA constitutive equations.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.32 no.12
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• pp.1153-1160
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• 2008

In this paper, the algorithm of Abaqus UMAT is introduced to analyze the shape memory alloy. The SMA has two main effects which show non-linearity. Due to this, it is hard to analyze SMA using analysis tools and to describe all of two effects. Therefore, in this study, the program using Abaqus UMAT based on Modified Brinson model is used to analyze SMA. The martensite fraction, the most important factor which defines SMA motion, is also calculated by Fortran program in UMAT. In addition, the tensile test of SMA specimen is conducted. The availability of algorithm is proved by comparing analysis to experimental result.