• Journal of Biomedical Engineering Research
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• v.39 no.1
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• pp.43-47
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• 2018

Traditional electroencephalography (EEG)-based authentication systems generally use external stimuli that require user attention and relatively long time for authentication. The aim of this study is to investigate the feasibility of biometric authentication based on EEG without using any external stimuli. Seventeen subjects took part in the experiment and their EEGs were measured while repetitively closing and opening their eyes. For identifying each subject, we calculated inter- and intra-subject cross-correlation using changes in alpha activity (8-13 Hz) during eyes closed as compared to eyes open. In order to optimize the number of recording electrodes, we calculated authentication accuracy by progressively reducing the number of electrodes used in the analysis. Significant increase in alpha activity was observed for all subjects during eyes closed, focusing on occipital areas, and spatial patterns of changed alpha activity were considerably different between the subjects. A mean authentication accuracy of 92.45% was obtained, which was retained over 75% when using only 8 electrodes placed around occipital areas. Our results could demonstrate the feasibility of the proposed novel authentication method based on resting state EEGs.

• Proceedings of the Korea Information Processing Society Conference
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• 2020.11a
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• pp.1034-1035
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• 2020

인공지능은 스스로 학습하며 기존 통계 분석보다 탁월한 분석 역량을 지니고 있어 스마트팩토리 혁신에 새로운 전기를 마련할 것으로 기대된다. 이를 증명하듯 스마트팩토리의 주요 분야인 공정 간 연계 제어, 전문가 공정 제어, 로봇 자동화 등에서 활발한 연구가 이어지고 있다. 본 논문에서는 소포물 분류 시스템에 전통적인 룰 기반의 제어 방식 대신 다중 에이전트 강화 학습 제어 방식을 설계 및 적용하여 효과적인 행동 제어가 가능함을 입증한다.

• Journal of applied mathematics & informatics
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• v.18 no.1_2
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• pp.613-619
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• 2005

In this paper, we consider various types of convergence theorems of Choquet integral. We also show that the autocontinuity of finite fuzzy measure is equivalent to a convergence theorem with respect to convergence in measure.

• Carbon letters
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• v.26
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• pp.95-101
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• 2018

• 한국전산유체공학회:학술대회논문집
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• 2003.10a
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• pp.175-177
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• 2003

The convergence characteristics of the LV scheme for the Euler equations have been investigated by using the Von Neumann stability analysis. The results indicated that the convergence rate is governed by a specific combination of CFD parameters. Based on this insight, it is shown that the convergence characteristics of the LV scheme is not deteriorated at any grid aspect-ratio as long as the local time step is defined based on the parameter combination. The numerical results demonstrated that this time step definition provide a uniform convergence for grid aspect-ratios between one to$1{\times}10^{4}$.

• Journal of Engineering Education Research
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• v.24 no.6
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• pp.79-85
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• 2021

In a future society where cutting-edge science technology such as artificial intelligence becomes commonplace, the demand for talented people with basic knowledge of mathematics and science is expected to increase continuously, and the educational infrastructure suitable for the characteristics of future generations is still insufficient. In particular, in the case of students taking convergence courses including practical training, there was a problem in communication with the instructor. In this study, we looked at the current status of distance learning at domestic universities that came suddenly due to the global pandemic of COVID-19. In addition, a case study of the use of technology was conducted to facilitate the interaction between instructors and learners through case analysis of distance classes in convergence subjects. Therefore, this study aims to introduce the case of developing lecture contents for smooth convergence education in a non-face-to-face educational environment targeting the developed AI convergence courses and applying them to the education of enrolled students.

• Composites Research
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• v.31 no.2
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• pp.51-56
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• 2018

A new study was carried out to utilize a pencil drawing paper sensor (PDPS), which drew a line using a pencil on the paper, as a sensor. The sensing effect on 3 different papers based on the properties of PDPS was compared. The specimens were prepared by drawing 4B pencils on plain (A4), Hwasun, and Han papers. The silver paste was used to give good electrical contacts of the copper wires and the pencil drawn line. The chemical structures of 3 papers for PDPS by FT-IR spectrum analysis were similar and the comparative compact states of each paper were observed by optical microscope. From statistical evaluation of tensile strength using 3 papers, plain paper was chosen to be best for the PDPD. The optimum drawing number of PDPD was determined by changing the thickness of the paper with the drawing number. Electrical resistance (ER) with graphite on 3 different papers were compared. The changes in compression was observed through cyclic compressive test of composite materials, it was possible to predict the degree of strain sensing under compressive test. It leads to expectation of properties.

• Journal of the Korean Society of Industry Convergence
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• v.23 no.5
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• pp.875-880
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• 2020

In this paper, a novel 3-DOF hybrid robot with enlarged workspace is presented for high speed applications. The 3-DOF hybrid robot is made up of one linear actuator and 2-DOF planar parallel robot in series. The actuation consists of one ball-screw to make one linear motion and two rotary ball-screws to transmit rotational motion to 2-DOF parallel robot. The workspace can be enlarged according to ball-screw stroke and the moving inertia can be reduced due to locating all the heavy actuators at the fixed base. The inverse kinematics and workspace analyses are presented. The robot prototype and PC-based control system are developed.

• Transactions of the Korean Society of Automotive Engineers
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• v.19 no.4
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• pp.84-90
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• 2011

In active noise control filter, LMS algorithms which used for control filter, assure the convergence property, and computational burden of these algorithms are proportionate to the filter taps. The convergence speed of LMS algorithms is mainly determined by value of the convergence coefficient, so optimal selection of the value of convergence coefficient is very important. In this paper, We proposed novel adaptive fuzzy logic LMS algorithms with FIR filter structure which has better convergence speed and less computational burden than conventional LMS algorithms, for single channel active noise control with ill conditioned signal case. Computer simulations were performed to show the effectiveness of a proposed algorithms.

• Journal of information and communication convergence engineering
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• v.9 no.4
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• pp.396-400
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• 2011

P2P(peer to Peer) network is a distributed network architecture composed of participants that make a portion of their resources directly available to other network participants, without the need for a central server. Currently, convergence network industry using wired and mobile are grows rapidly. So P2P protocols will be used between mobile and wired network. But current P2P protocols are focused on the wired networks only and there are no simulators for performance analysis of mobile P2P. In this paper, we design a P2P simulation system for performance analysis of P2P protocols in mobile, wired and convergence networks. It is constructed by a well-known mobile network simulator and wired based P2P protocol simulator. Finally we have implemented a smart TV test-bed using our P2P test-bed for convergence networks.