• 한국추진공학회:학술대회논문집
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• 한국추진공학회 2008년도 제31회 추계학술대회논문집
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• pp.23-27
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• 2008

본 논문에서는 실수코드 유전 알고리즘(RCGA)과 인공신경망(ANN)을 이용하여 항공기용 터보 축엔진의 결함 진단에 관한 연구를 수행하였다. 인공신경망만을 이용하여 엔진의 결함을 판단 할 경우 많은 학습데이터 때문에 지역 최소점으로 수렴하는 단점이 있다. 이를 개선하기 위해 전역 최소점을 찾는 능력이 뛰어난 실수코드 유전 알고리즘을 사용하였다. 5% 이내의 RMS 결함오차로 높은 결함 예측 신뢰도를 가짐을 확인하였다.

• Steel and Composite Structures
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• 제31권5호
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• pp.529-539
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• 2019

Current paper deals with thermoelastic static and free vibrational behaviors of axisymmetric thick cylinders reinforced with functionally graded (FG) randomly oriented graphene subjected to internal pressure and thermal gradient loads. The heat transfer and mechanical analyses of randomly oriented graphene-reinforced nanocomposite (GRNC) cylinders are facilitated by developing a weak form mesh-free method based on moving least squares (MLS) shape functions. Furthermore, in order to estimate the material properties of GRNC with temperature dependent components, a modified Halpin-Tsai model incorporated with two efficiency parameters is utilized. It is assumed that the distributions of graphene nano-sheets are uniform and FG along the radial direction of nanocomposite cylinders. By comparing with the exact result, the accuracy of the developed method is verified. Also, the convergence of the method is successfully confirmed. Then we investigated the effects of graphene distribution and volume fraction as well as thermo-mechanical boundary conditions on the temperature distribution, static response and natural frequency of the considered FG-GRNC thick cylinders. The results disclosed that graphene distribution has significant effects on the temperature and hoop stress distributions of FG-GRNC cylinders. However, the volume fraction of graphene has stronger effect on the natural frequencies of the considered thick cylinders than its distribution.

• 한국정보통신학회:학술대회논문집
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• 한국정보통신학회 2014년도 추계학술대회
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• pp.201-202
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• 2014

본 논문에서는 우리에게 정신적, 금전적으로 상당한 피해를 주는 국내외 해킹 사례를 살펴보도록 한다. 웹 사이트 공격의 약 75%가 응용프로그램 즉, S/W의 취약점을 악용한 것임을 상기시킨다. 그리고 이러한 취약점들을 많이 가지고 있는 S/W 개발 보안의 주요 이슈들을 알아보도록 한다.

• Geomechanics and Engineering
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• 제30권4호
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• pp.363-372
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• 2022

One of the most frequent issues in tunnel excavation is the collapse of rock blocks and the dropping of rock fragments from the tunnel face. The tunnel face can be reinforced using a number of techniques. One of the most popular and affordable solutions is the use of face longitudinal dowels, which has benefits including high strength, flexibility, and ease of cutting. In order to examine the reinforced face, this work shows the longitudinal deformation profile and ground response curve for a tunnel face. This approach is based on assumptions made during the analysis phase of problem solving. By knowing the tunnel face response and dowel behavior, the interaction of two elements can be solved. The rock element equation derived from the rock bolt method is combined with the dowel differential equation to solve the reinforced ground response curve (GRC). With a straightforward and accurate analytical equation, the new differential equation produces the reinforced displacement of the tunnel face at each stage of excavation. With simple equations and a less involved computational process, this approach offers quick and accurate solutions. The FLAC3D simulation has been compared with the suggested analytical approach. A logical error is apparent from the discrepancies between the two solutions. Each component of the equation's effect has also been described.

• 한국멀티미디어학회논문지
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• 제25권10호
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• pp.1416-1432
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• 2022

The access control system is a system that allows users to selectively enter the building by granting an access key to the user for security. Access keys with weak security are easily exposed to attackers and cannot properly perform the role that authenticates users. Access code keys should be protected from forgery or spoofing. For this reason, access key verification service models is important in security. However, most models manage all access keys on one central server. This method not only interrupts all services due to server errors, but also risks forgery and spoofing in the process of transmitting access keys. Therefore, blockchain algorithms are used to reduce this risk. This paper proposes a blockchain-based access key verification service model that used distributed stored blockchain gateways on storing access keys and authenticates the user's identity based on them. To evaluate the performance of this model, an experiment was conducted to confirm the performance of the access key forgery recovery rate and the blockchain network performance. As a result, the proposed method is 100% forgery recovery rate, and the registration and verification process is evaluated at 387.58 TPS and 136.66 TPS.

• 한국엔터테인먼트산업학회논문지
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• 제14권3호
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• pp.133-138
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• 2020

증강현실에 있어서 인터랙션은 중요한 요소이다. 하지만 현재 증강현실 콘텐츠에서 인터랙션 기능은 많이 부족한 실정이다. 현실 환경 정보를 많이 가져오는 것이 증강현실의 발전 방법 중 하나이며, 인터랙션도 자연스레 발전하게 된다. 본 논문에서는 인터페이스 도구로 널리 사용되는 손을 통해 증강현실 환경에서 자연스러운 인터랙션을 위해 Leap Motion을 이용하였고 기존의 디스플레이 터치방식의 한정적인 인터랙션에서 보다 확장시켜 자연스러운 인터랙션을 연출하였다. 이러한 인터랙션의 발전은 추후 증강현실 뿐만 아니라 여러 콘텐츠들의 발전에 기여할 것이다.

• 산업과 과학
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• 제2권1호
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• pp.1-7
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• 2023

스마트시티와 스마트 홈에서 사물인터넷의 사용이 필수적이다. 사물인터넷의 핵심인 센서 노드들에 대한 보안성이 취약하여 해킹공격을 받을 경우 실생활에 치명적인 영향을 미칠 만큼 심각하나, 사물인터넷을 구성하는 센서 노드들의 물리적 기술적 제약으로 인하여 보안모듈이 탑재되어 운영되지 못하고 있는 실정이어서 사물인터넷용 경량 보안 통신 프로토콜을 개발하여 사물인터넷의 보안성을 향상하고, 앞으로 4차산업혁명 시대에 맞는 안전한 사물인터넷 환경 구축을 위해 본 연구를 실시하며, IoT사물인터넷 인증체제 구축과 통신의 기밀성을 높이기 위한 키 관리 및 식별자 개발을 대한 제안을 하여 안전하고 편리한 스마트시티와 스마트 홈을 구축하는데 기여한다.

• Journal of information and communication convergence engineering
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• 제21권2호
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• pp.103-109
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• 2023

We investigated the antipodal-symmetric dispersion maps of a dispersion-managed link with a midway optical phase conjugator to compensate for the distorted 960 Gb/s wavelength division multiplexed (WDM) signal caused by these effects. The proposed antipodal-symmetric dispersion map has various shapes depending on the detailed design scheme. We confirmed that the dispersion-managed link designed with the dispersion map of the antipodal-symmetric structure is more advantageous than the conventional uniform dispersion map for compensating WDM channels. It was also confirmed that among the antipodal-symmetric structures, the dispersion map configured with the S-1-profile, in which S is inverted up and down, was more effective for distortion compensation than the dispersion map configured with the S-profile. In particular, we confirmed that the S-1-profile can broaden the optical pulse width intensively at a short transmission distance, more effectively compensating for the distorted WDM channel. Because this structure makes the intensity of the optical pulse relatively weak, it can decrease the nonlinear Kerr effect.

• 융합경영연구
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• 제2권2호
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• pp.1-9
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• 2014

This study investigated solutions of not only weak organization but also poor communication with customers from point of view of SNS such as Naver blog, Naver band, Kakao Talk and Facebook to promote local business market. The study gave strategies: First, SNS marketing strategy shall be used to do public relations and communicate in accordance with features of each SNS. Naver Blog that is opened SNS shall be used to do public relations and to invite new customers, and Kakao Talk that is closed SNS shall be used to increase customers having high loyalty, and Facebook that has both properties of SNS, that is to say, openness and closure, shall be used to raise effects of word-of-mouth to make use of new sales window. The communication can find out customers' needs to provide customers with customized services. Second, Naver Band and/or cafe shall be opened to increase link and friendliness and to have community consciousness realizing common goal and to destroy merchants' helplessness and individualism and to make change of the market for the place of community. Changes among the merchants may get better ideas to do events continuously and to get more SNS marketing effects and synergy. Third, the merchants shall make change not momentarily but continuously by making efforts steadily. Good communication in and out of the market may create inherent brand value to differ from super chain and/or SSM and to increase sales as well as traditional market image and to attain customers' loyalty.

• 문화기술의 융합
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• 제10권3호
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• pp.145-154
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• 2024

행정 빅데이터를 활용하는 예측 모형을 운영하기 위해서는 정책의 변화 및 변동성 심한 데이터의 특성이 고려가 되어야만 한다. 이런 상황을 고려하여 본 연구에서는 Cut-off Voting Classifier(CVC) 알고리즘을 제안한다. 제안하는 알고리즘은 여러개의 약 분류기를 활용하여 적중률이 급격하게 하락하는 것을 방지하는 알고리즘이다. 본 연구에서는 제안하는 알고리즘을 실험을 통해 성능을 검증한다. 성능검증 결과 급격하게 예측모형 적중률이 하락하는 상황에서도 안정적으로 예측률을 유지한다는 것을 입증할 수 있었다.