• ETRI Journal
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• v.8 no.3
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• pp.15-23
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• 1986

ISL(Integrated Schottky Logic)의 고집적화를 위하여 종래의 p-n 접합 격리 방법 대신에 산화막으로 격리시킨 2마이크론의 최소 설계치수를 갖는 소자를 설계, 제작하여 특성을 분석하였다. 접합 형성을 위한 불순물은 이온 주입법을 이용하여 고속소자가 필연적으로 갖추어야 하는 얕은 접합으로 형성을 시켰으며, 출력단의 쇼트키 다이오드는 백금 실리 사이드를 이용하였다. 링 발진기의 특성에서 최소 전달지연 시간은 한 게이트당 5.7ns의 속도 특성과 논리 진폭은 360mV의 현격한 특성을 나타내었다 .

• The Journal of the Korea institute of electronic communication sciences
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• v.10 no.3
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• pp.387-393
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• 2015

In Electronic Commerce and Secret Communication based on ECC over finite field, if the sender and the receiver use different basis of finite fields, then the time of communication should always be delayed. In this paper, we analyze the number of bases-transformations needed for Electronic Signature in Electronic Commerce and Secret Communication based on ECC over finite field between H/W and S/W implementation systems and introduce the anomalous basis of finite fields using AOP which is efficient for H/W, S/W implementation systems without bases-transformations for Electronic Commerce and Secret Communication. And then we propose a new multiplier based on the anomalous basis of finite fields using AOP which reduces the running time by 25% than that of the multiplier based on finite fields using trinomial with polynomial bases.

• Sleep Medicine and Psychophysiology
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• v.26 no.1
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• pp.16-22
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• 2019

Objectives: The objective of this study was to investigate the correlation between insufficient sleep and visuospatial memory in adolescents using a computerized neurocognitive function test. Methods: A total of 103 high school students (26 males and 77 females; mean age $17.11{\pm}8.50years$) without a serious psychiatric problem was recruited. All subjects were requested to complete a self-report questionnaire about weekday total sleep time and weekend total sleep time. The epworth sleepiness scale (ESS) and the beck depression inventory (BDI) were administered to measure daytime sleepiness and symptoms of depression. Seven subsets of the Cambridge Neuropsychological test automated battery were examined to assess visuospatial memory. Results: After controlling for age, sex, ESS, and BDI, longer weekend total sleep time was correlated with poor performance on delayed matching to sample (r = -0.312, p = 0.002) and immediate recall on pattern recognition memory (r = -0.225, p = 0.025). Increased weekend catch-up sleep time was correlated with poor performance of delayed matching to sample (r = -0.236, p = 0.018), immediate recall on pattern recognition memory (r = -0.220, p = 0.029), and delayed recall on pattern recognition memory (r = -0.211, p = 0.036) after controlling for age, sex, ESS, and BDI. Conclusion: This study showed that increased weekend catch-up sleep time reflecting insufficient weekday sleep were associated with poor performance in delayed recall tasks of visual memory. This finding suggests that insufficient sleep during adolescence might produce a decline of visuospatial memory.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.58 no.9
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• pp.1809-1814
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• 2009

In this paper, the problem of stability analysis for neural networks with discrete and distributed time-varying delays is considered. By constructing a new Lyapunov functional, a new delay-dependent stability criterion for the network is established in terms of LMIs (linear matrix inequalities) which can be easily solved by various convex optimization algorithms. Two numerical example are included to show the effectiveness of proposed criterion.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.18 no.6
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• pp.176-182
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• 2004

This paper proposes a frequency transfer function synthesis for simplifying a high-order model with time delay to a low-order model. The model reduction is based on minimizing the m function weighted by the numerator polynomial of reduced systems. The proposed methods provide a better fitness within low frequency. Four examples are given to illustrate the feasibilities of the suggested schemes.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.11 no.4
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• pp.565-574
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• 2000

A new ground penetrating radar imaging method for the estimation of buried artificial structures location and their approximate shapes in dispersive lossy ground is investigated. Fundamental idea is based on estimating delayed time and amplitude retrieval coefficients from scattered signals by buried scatterers. Using absolute value integration of each scanning site not only improve the accuracy of measured scattered signal, but also offers convenient ways to extract the image of buried structures. Multi-term Debye model was employed to describe a dispersive and lossy ground medium. We used the finite difference time domain method to discretize the wave equation in continuous form into the machine suitable form. This imaging method uses a new wave path tracing technique in time domain, which is helpful to identify the exact position of buried structures against the ground surface fluctuations.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.25 no.5A
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• pp.602-610
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• 2000

There has been increasing interest in broadband services to mobile terminals. Wireless ATM will be used to support broadband services for future generation mobile service. We propose an algorithm for handover in wireless ATM LANs. We have studied how to treat the loop cancellation and optimization of path extension handover scheme, and present path optimization algorithms : polyangular loop cancellation and triangular loop cancellation. We express the location of MT(mobile terminal) by direction angle, and the direction angles can be converted into direction vectors. Using direction vectors, we can find the current optimal path of MT. The analysis and the experimental results show that the proposed scheme provides the better performance than that of anchor rerouting scheme in average handover delay, handover disruption delay, and buffer requirements.

• Proceedings of the KIEE Conference
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• 1997.07c
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• pp.878-879
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• 1997

본 논문에서는 전자기 과도현상 해석을 위한 다단자 회로망 등가표현법을 제안한다. 이 방법은 M개의 경계모선을 가진 축약대상 계통의 과도특성을 시간 영역에서 분석하며 이를 이용해 M 개의 노톤형 이산시간 등가 어드미턴스 필터꼴의 등가시스템을 구현한다. 이 때 각각의 등가 어드미턴스 필터 모델들은 해당 경계모선에서의 구동점 어드미턴스 특성을 나타내는 부분과 나머지 M-1 개의 등가 종속전류원으로 구성된다. 또한 이 등가 종속전류원들은 각 경계모선을 연결하는 분포정수 회로요소들로 인한 시지연 효과를 명확하게 반영할 수 있는 구조를 갖는다. 완성된 M 단자쌍 모델을 해석대상 시스템에 대한 이산시간 표현형과 쉽게 결합하여 원하는 전자기 과도현상 모의해석을 수행할 수 있다. 축약대상 시스템과 2 개의 경계모선을 통해 연결된 시험계통을 대상으로 모선지락 사고시 과전압과 스위칭 써지를 모의해석한 결과 제안하는 방법이 타당함을 확인할 수 있었다.

• Journal of Internet Computing and Services
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• v.17 no.5
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• pp.1-8
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• 2016

This paper proposes a novel broadcast scheduling algorithm for wireless large-scale networks based on theory of complex networks. In the proposed algorithm, the network topology is formed based on a scale-free network and the probability of link distribution is analyzed. In this paper, the characteristics of complex systems are analyzed (which are not concerned by the existing broadcast scheduling algorithm techniques) and the optimization of network transmission efficiency and network time delay are provided.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.30 no.7 s.250
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• pp.671-681
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• 2006

This study focuses on the development of numerical procedure to analyze the nonlinear combustion instabilities in liquid rocket engine. Nonlinear behaviors of acoustic instabilities are characterized by the existence of limit cycle in linearly unstable engines and nonlinear or triggering instability in linearly stable engines. To discretize convective fluxes with high accuracy and robustness, approximated Riemann solver based on characteristics and Euler-characteristic boundary conditions are employed. The present procedure predicts well the transition processes from initial harmonic pressure disturbance to N-like steep-fronted shock wave in a resonant pipe. Longitudinal pressure oscillations within the SSME(Space Shuttle Main Engine) engine have been analyzed using the pressure-sensitive time lag model to account for unsteady combustion response. It is observed that the pressure oscillations reach a limit cycle which is independent of the characteristics of the initial disturbances and depends only on combustion parameters and operating conditions.