• KSII Transactions on Internet and Information Systems (TIIS)
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• 제17권9호
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• pp.2529-2549
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• 2023

For effectively lowering down the risk of cyber threating, the zero-trust architecture (ZTA) has been gradually deployed to the fields of smart city, Internet of Things, and cloud computing. The main concept of ZTA is to maintain a distrustful attitude towards all devices, identities, and communication requests, which only offering the minimum access and validity. Unfortunately, adopting the most secure and complex multifactor authentication has brought enterprise and employee a troublesome and unfriendly burden. Thus, authors aim to incorporate machine learning technology to build an employee behavior analysis ZTA. The new framework is characterized by the ability of adjusting the difficulty of identity verification through the user behavioral patterns and the risk degree of the resource. In particular, three key factors, including one-time password, face feature, and authorization code, have been applied to design the adaptive multifactor continuous authentication system. Simulations have demonstrated that the new work can eliminate the necessity of maintaining a heavy authentication and ensure an employee-friendly experience.

• 한국멀티미디어학회논문지
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• 제24권8호
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• pp.1171-1177
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• 2021

Measuring and evaluation of audience's visual message perception are crucial process for scientific production of visual content. This study tried to evaluate the difference of viewer's awareness of visual object depends on his or her inherent characteristics like conservatism using an eye tracker system. Especially, this experiment tested research questions about positive correlation between conservatism and peoples' eye movements following the sound visual messages. 57 subjects participated in the test. Two different groups were exposed to two visual elements representing 'the conservative' and 'the liberal'. The results showed that people tended to have different way of seeing visual objects according to their inherent characteristics. Also by comparing the gaze time at the object and area of interest(AOI) in visual, this study is able to verify the existence of 'positive way of seeing' and 'negative way of seeing'. The two different ways of seeing have their own trail of eye movement.

• 대한원격탐사학회지
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• 제39권5_2호
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• pp.771-783
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• 2023

This study aims to compare the performance of each machine learning model for preparing a grid-based disaster risk map related to flooding in Jung-gu, Ulsan, for Typhoon Chaba which occurred in 2016. Dynamic data such as rainfall and river height, and static data such as building, population, and land cover data were used to conduct a risk analysis of flooding disasters. The data were constructed as 10 m-sized grid data based on the national point number, and a sample dataset was constructed using the risk value calculated for each grid as a dependent variable and the value of five influencing factors as an independent variable. The total number of sample datasets is 15,910, and the training, verification, and test datasets are randomly extracted at a 6:2:2 ratio to build a machine-learning model. Machine learning used random forest (RF), support vector machine (SVM), and k-nearest neighbor (KNN) techniques, and prediction accuracy by the model was found to be excellent in the order of SVM (91.05%), RF (83.08%), and KNN (76.52%). As a result of deriving the priority of influencing factors through the RF model, it was confirmed that rainfall and river water levels greatly influenced the risk.

• 한국산학기술학회논문지
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• 제16권12호
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• pp.8753-8759
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• 2015

터빈 발전 사이클에서의 안정적인 발전 출력 유지관리를 위해서는 검증된 성능 측정 데이터 그룹과 이를 바탕으로 한 발전 출력 성능 계산 절차의 수립이 필요하다. ASME PTC(Performance Test Code)의 성능 계산 절차를 기반으로 본 연구에서는 터빈 출력에 의한 발전기 출력 성능 산정을 위해서 터빈 팽창선 모델과 발전기 출력 측정 데이터의 입력 검증 모델을 구성하였다. 또한 불확실한 측정 데이터에 대한 검증 모델도 구성하였다. 지난 연구에서는 신경회로망과 커널 회귀의 학습 방법을 사용하였으나 본 연구에서는 미측정 데이터에 대한 보완을 하기 위하여 서포트 벡터 머신 모델을 사용하여 발전기 출력 계산 데이터의 학습 모델을 구성하였으며, 학습 모델 구성을 위해서 관련 변수의 선정을 위한 절차와 학습 데이터 구간을 설정하는 알고리듬을 개발하였다. 학습의 결과 오차는 약 1% 범위 안에 있게 되어 추정 및 학습 모델로서 유용함을 입증하였다. 이 학습 모델을 사용하여 측정 데이터 중 상실된 부분에 대한 추정 모델을 구성함으로써, 터빈 사이클 보정 성능 계산의 신뢰성을 향상시킬 수 있음을 검증하였다.

• 한국컴퓨터정보학회논문지
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• 제16권5호
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• pp.127-134
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• 2011

화면을 모니터링하고 있는 시스템에서 사용자가 시선을 화면에 집중하고 있는가를 판단하고 제어할 수 있는 유한 상태 기계를 설계 및 구현하였다. 유한 상태 기계는 화면을 응시하고 있는 눈동자의 상황에 대한 집합과 화면에 집중하고 있는 상태의 집합을 이를 기반으로 구성되었다. 특히 상태 집합을 3종류-주요 상태, 예비 상태, 잠재 상태로 분류하였다. 이전의 상황과 현재의 상황을 연계하여 현 상태를 판단하는 상황 이력을 이용함으로써 판단의 정확도를 높였다. 이 유한 상태 기계에 대하여, 기존의 눈동자 검출 방법에서 얻은 눈동자 위치 데이터를 이용하여 시뮬레이터를 구현하고 작동과정의 모니터링을 통하여 검증하였다. 실제 눈동자의 이미지를 바탕으로 실험한 결과로 상황 이력을 이용한 판정은 현재의 응시 상태가 1회성 또는 장기적인 상태인가를 판단할 수 있는 장점을 보였다.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2001년도 춘계학술대회논문집A
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• pp.108-113
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• 2001

Recently, the mechanical structures applied to many industrial products, especially in electronic products, appear to be miniaturized and complicated. This trend makes it difficult to analyze the stress distribution of those mechanical structures and generates new challenges for precise measurement of strain. Therefore, generally most of those cases largely depend on the finite element analysis. But the development of optical metrology which has the capability of non-contact, full-field and precise measurement makes it possible to solve these measuring problems. Among the optical measurement techniques, the electronic speckle pattern interferometry (ESPI) has been developed and considered as one of the most useful tools for measuring displacement and deformation. But the shortage of recognition and difficulties of measurement have limited its industrial applications in spite of its excellent capabilities. Therefore in this study, in order to enhance the industrial application of ESPI, the measurement of in-plane displacement of mechanical structure with ESPI, which is applied to washing machine and cannot be measured by strain gauges, was performed. And the verification of validity of FEA results was also done.

• 한국멀티미디어학회:학술대회논문집
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• 한국멀티미디어학회 2002년도 춘계학술발표논문집(하)
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• pp.1001-1006
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• 2002

KVM에서의 검증단계는 크게 두가지로 나된다. 일반적으로 처리되는 Off-device에서의 사전검증과 실제 VM에 탑재되어 수행되는 in-device에서의 검증이다. 전자의 경우, 실행시 검증을 쉽게 하기 위해서 클래스 파일에 특별한 속성을 가진 스택맵을 추가한다. 이렇게 추가된 스택맵은 KVM상에서 보다 효율적인 검증을 위한 것으로써, 본 논문에서는 이러한 스택맵을 분석하였다.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1988년도 한국자동제어학술회의논문집(국내학술편); 한국전력공사연수원, 서울; 21-22 Oct. 1988
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• pp.285-288
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• 1988

Despite of the low productivity, the manual programming for NC machining is still widly used because of it's economical reasons. In this study, the computer assisted manual programming system CAMP which assits the efficient verification of MCD(Machine Control Data) is presented. The system can detect sysntax errors, graphically display tool motions and eventually diagnose programming techniques. The case study is applied for the NC turning operations.

• 한국공작기계학회논문집
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• 제16권5호
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• pp.84-89
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• 2007

This research was done on the basis of assumption that there is a relationship between welding parameters and geometry of the back-bead being a gap in arc welding. Multiple regression analysis was used as method for predicting the geometry of the back-bead. The analysis data and the verification data were used for the formation of multiple regression analysis. The method was used to perform the prediction of the back-bead.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1997년도 한국자동제어학술회의논문집; 한국전력공사 서울연수원; 17-18 Oct. 1997
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• pp.744-747
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• 1997

High performance digital computer technology enables the digital computer-based controllers to replace traditional analog controllers used for factory automations. This replacement, however, brings up the side effects caused by discrete quantization and non-real-time execution of control softwares. This paper describes the structure of real-time simulator and controller that can be used for design and verification of real-time digital controllers. The virtual machine concept adopted by real-time simulator make the proposed simulator be independent from the specific hardware platforms. The proposed system can also be used in the loosely coupled distributed environments connected through local area network using real-time message passing algorithm and virtual data table based on the shared memory mechanism.