• 대한수학회보
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• 제40권3호
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• pp.351-363
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• 2003

In the present paper, some general convergence principles are established in metric spaces and then theses principles are applied to the convergence of the iterative sequences for approximating fixed points of certain classes of mappings. By virtue of our principles, most of the latest results obtained by several authors can be deduced easily.

• IEIE Transactions on Smart Processing and Computing
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• 제6권2호
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• pp.124-128
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• 2017

A light guide improves the spatial resolution of a gamma ray imaging system by diffusing the scintillation light. Similarly, light diffusion film, which has been applied to flat-panel-display engineering, spreads the light from the light guide panel. In this study, we adopted light diffusion film for the light guide of a gamma ray imaging system, and evaluated its diffusion characteristics. We compared the light diffusion performance of the film to an ordinary acrylic plate. As a result, the diffusion film widely spreads scintillation light. As for the thickness of the light guide, we acquired more distinct images with three films overlapped than with an acrylic plate. We expect light diffusion film to be a promising candidate for light guides in gamma ray imaging systems.

• Journal of information and communication convergence engineering
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• 제13권3호
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• pp.197-204
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• 2015

In this paper, we present an algorithm for the detection of illegally parked vehicles based on a combination of some image processing algorithms. A digital camera is fixed in the illegal parking region to capture the video frames. An adaptive Gaussian mixture model (GMM) is used for background subtraction in a complex environment to identify the regions of moving objects in our test video. Stationary objects are detected by using the pixel-level features in time sequences. A stationary vehicle is detected by using the local features of the object, and thus, information about illegally parked vehicles is successfully obtained. An automatic alarm system can be utilized according to the different regulations of different illegal parking regions. The results of this study obtained using a test video sequence of a real-time traffic scene show that the proposed method is effective.

• Journal of information and communication convergence engineering
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• 제21권3호
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• pp.198-207
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• 2023

Responding to changes in artificial intelligence models and the data environment is crucial for increasing data-learning accuracy and inference stability of industrial applications. A learning model that is overfitted to specific training data leads to poor learning performance and a deterioration in flexibility. Therefore, an early stopping technique is used to stop learning at an appropriate time. However, this technique does not consider the homogeneity and independence of the data collected by heterogeneous nodes in a differential network environment, thus resulting in low learning accuracy and degradation of system performance. In this study, the generalization performance of neural networks is maximized, whereas the effect of the homogeneity of datasets is minimized by achieving an accuracy of 99.7%. This corresponds to a decrease in delay time by a factor of 2.33 and improvement in performance by a factor of 2.5 compared with the conventional method.

• 한국정보처리학회:학술대회논문집
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• 한국정보처리학회 2020년도 춘계학술발표대회
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• pp.161-164
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• 2020

경량 암호는 컴퓨팅 파워가 부족한 저사양 프로세서를 위해 개발되었다. CHAM은 국산 경량 암호 중 하나로, 세 가지의 규격을 제공하며 ARX 구조를 사용한 암호이다. CHAM 발표 이후, 라운드 수를 조절하여 성능을 향상시킨 Revised CHAM이 제안되었다. 기존 CHAM은 8-bit AVR 프로세서 상에서 최적 구현이 이루어졌지만, 최신 기술인 Revised CHAM은 해당 구현물이 존재하지 않는다. 따라서 8-bit AVR 프로세서를 대상으로 Revised CHAM-64/128을 최적 구현하여 최상의 성능으로 연산이 진행되도록 한다. 본 논문에서는 최적 구현에 사용한 기법들을 소개하며, 기존에 제안된 기법과 성능 비교를 통해 본 기법의 우수함을 서술한다.

• 한국정보처리학회:학술대회논문집
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• 한국정보처리학회 2023년도 추계학술발표대회
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• pp.1254-1256
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• 2023

반도체 공정은 주로 진공 중에서 이루어 지며 진공을 잘 유지하는 것이 매우 중요하고 여러 가지 종류의 펌프가 사용이 된다. 저진공펌프로 많이 사용되는 로타리 펌프에 대해서 진동 및 온도센서를 부착하고 펌프의 상태에 따른 진동의 변화 및 온도의 변화를 연구 하고 펌프의 예지 보전에 활용할 수 있도록 하였다.

• 한국정보처리학회:학술대회논문집
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• 한국정보처리학회 2024년도 춘계학술발표대회
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• pp.646-647
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• 2024

사이버 범죄가 증가함에 따라 익명성을 보장하는 암시장인 다크웹 내 불법적인 활동에 대한 모니터링의 중요성이 커졌다. 최근 다양한 분야에서 ChatGPT 의 쓰임이 주목받고 있듯이 다크웹에서도 전용 GPT 가 등장하였으며, 다크웹 생태계를 분석하고 정보를 수집하는데 이러한 다크웹 전용 생성형 인공지능 모델을 활용할 수 있다. 본 연구에서는 다크웹 GPT 에서 불법 행위와 관련된 질의를 통해 정보를 수집하고 해당 정보가 표면웹과 다크웹 상에서 다르게 쓰이고 있음을 확인함으로써 수사를 위한 다크웹 전용 GPT 활용 가능성 및 프롬프트 엔지니어링의 필요성을 탐구한다.

• Journal of information and communication convergence engineering
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• 제2권1호
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• pp.36-39
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• 2004

In this paper, a method of improving the learning speed and convergence rate is proposed to exploit the advantages of artificial neural networks and neuro-fuzzy systems. This method is applied to the XOR problem, n bit parity problem, which is used as the benchmark in the field of pattern recognition. The method is also applied to the recognition of digital image for practical image application. As a result of experiment, it does not always guarantee convergence. However, the network showed considerable improvement in learning time and has a high convergence rate. The proposed network can be extended to any number of layers. When we consider only the case of the single layer, the networks had the capability of high speed during the learning process and rapid processing on huge images.

• Structural Engineering and Mechanics
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• 제7권6호
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• pp.561-573
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• 1999

A $C^*$-convergence algorithm for finite element analysis has been proposed by Bigdeli and Kelly (1997) and elements for the first three levels applied to planar elasticity have been defined. The fourth level element for the new family is described in this paper and the rate of convergence for the $C^*$-convergence algorithm is investigated numerically. The new family adds derivatives of displacements as nodal variables and the number of nodes and elements can therefore be kept constant during refinement. A problem exists on interfaces where the derivatives are required to be discontinuous. This problem is addressed for curved boundaries and a procedure is suggested to resolve the excessive interelement continuity which occurs.

• East Asian mathematical journal
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• 제38권3호
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• pp.277-292
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• 2022

This study investigates the convergence of the optimal consumption and investment policies in a binomial-tree model to those in the continuous-time model of Merton (1969). We provide the convergence in explicit form and show that the convergence rate is of order ∆t, which is the length of time between consecutive time points. We also show by numerical solutions with realistic parameter values that the optimal policies in the binomial-tree model do not differ significantly from those in the continuous-time model for long-term portfolio management with a horizon over 30 years if rebalancing is done every 6 months.