• Proceedings of the Computational Structural Engineering Institute Conference
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• 2010.04a
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• pp.742-745
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• 2010

본 논문은 초고층구조물의 해석방법으로 탄성변형과 아울러 시간의존성을 가진 크리프와 건조수축에 의한 비탄성변형을 고려한 비선형 시공단계 해석법을 제시한다. 기존의 초고층구조물 해석에서 주로 행하는 기둥 축소량 해석은 실무자의 경험과 프로그램을 통한 간략화에 맞추어져 있다. 이는 실제 시공 시 발생하는 구조해석 요소들을 충분히 반영하지 못하여 계산 값과 실제 값 사이에 오차가 발생된다. 비선형 시공단계 해석은 실제 시공 때 발생되는 해석변수들을 고려한 단계별 해석의 수행이 가능하며, 시간의 의존성을 가진 creep과 shrinkage의 효과를 함께 고려하여 일괄해석의 문제점을 구조해석 단계에서 실제상황에 가까운 해석을 가능하게 할 수 있다. 이를 위해 시공단계해석이 가능한 범용 프로그램을 이용한 50층 규모의 3차원 골조 프레임 모델 예제 해석을 통하여 기존 해석법들과의 비교, 분석으로 시간의 의존성을 고려한 시공단계해석의 필요성을 제시한다. 본 논문에는 범용프로그램인 SAP2000(ver.14)와 CEB-FIP모델 코드를 사용 하였다.

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 2003.11a
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• pp.7-10
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• 2003

인터프레임 웨이블렛 부호화(Interframe Wavelet Coding)는 3D 서브밴드(Subband) 부호화라고도 하며, 기존의 DCT기반 Hybrid 동영상 부호화 방식에 비해 압축 효율이 우수하고. 특히 스케일러빌리티 기능이 뛰어난 부호화 방법이다. 인터프레임 웨이블렛 부호화 방법에서 복호화 과정 중 가장 연산 량이 많이 요구되는 역(inverse) 웨이블렛 변환이다 역 웨이블렛 변환의 연산 량은 복호화 과정에서 적용된 웨이블렛 변환과 동일한 연산량을 요구한다. 이는 순방향과 역방향에서 동일 길이의 필터와 분해 레벨을 사용해야 하기 때문이다. 이 웨이블렛 변환의 연산 량을 줄이기 위해 본 논문에서는 기존의 시간 밴드 영상에 대해 동일 한 웨이블렛 필터를 사용하여 공간 웨이블렛 필터를 적용하던 것을. 로우밴드에는 9/7 필터를 적용하고 하이 밴드에는 Haar필터를 사용하는 방법을 제안한다. PSNR 실험에서 기존의 9/7 필터만을 사용하는 경우와 비교한 결과 거의 차이가 없었다.

• Journal of the Korean Society for Railway
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• v.16 no.1
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• pp.1-6
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• 2013

In this study, the natural frequency and damping ratio of a four-harness satin woven glass/epoxy composite material are evaluated by means of modal tests and a finite element analysis. To achieve this goal, glass/epoxy beam specimens with different lengths and thicknesses were manufactured via autoclave curing. In the test, the maximum damping ratio was found to occur at the lowest test frequency. As the test frequency increased, the damping ratio decreased exponentially to a critical value. After that value, the damping ratio increased gradually to the maximum test frequency.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2001.05a
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• pp.633-637
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• 2001

In this paper, we proposed model creation algorithm for multiple moving objects tracking. The proposed algorithm is divided that the initial model creation step as moving objects are entered into background image and the model reformation step in the moving objects tracking step. In the initial model creation step, the initial model is created by AND operating division image, divided using difference image and clustering method, and edge image of the current image. In the model reformation step, a new model was reformed in the every frame to adapt appearance change of moving objects using Hausdorff Distance and 2D-Logarithmic searching algorithm. We simulated for driving cart in the road. In the result, model was created over 98% in case of irregular approach direction of cars and tracking objects number.

• Management & Information Systems Review
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• v.32 no.4
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• pp.209-225
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• 2013

The effects of message framing have been major research themes in marketing and advertising field and several studies on these effects have been conducted. The purpose of this study is to examine the direct effects of public service Advertising message framing and moderating role of temporal distance. The results indicate that message types have a significant effect on message reliability and acceptance intention. In addition, temporal distance plays a significant moderating role between the message types and the dependent variable. The results of this study suggest various implications in the public service advertising area.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• v.9 no.1
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• pp.663-666
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• 2005

Problem of compatibility, contents protection, contents circulation etc. was caused between contents offerer and consumers by indiscreet rights technical development about digital contents. Therefore, MPEG-21 framework proposed the REL(Right Expression Language) based on XML(eXtensible Markup Language) by rights expression language for rights management. We designed and implemented of the REL document editing system that rights creation and edit are available efficiently about contents easily without comprehension of MPEG-21 framework and client system that present consumption method of REL document.

• Proceedings of the Korean Society of Disaster Information Conference
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• 2023.11a
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• pp.73-74
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• 2023

본 논문에서는 음향센서를 기반으로 한 지하시설물 화재 위험감지 방법을 제안하였다. 음향센서는 진동이나 광센서처럼 접촉식이 아니기 때문에 결로가 발생하고 있는 취약구간에 설치하여 보다 효율적으로 활용이 가능하고 지하시설물 내부에 설치된 기기나 장비들과 상호작용하거나 간섭하지 않기 때문에 안전하게 관리가 가능하다. 이러한 특징으로 지하 시설물에서 내 통행이 불편하여 관리하기 힘든 구간이나 결로가 많아 화재안전에 주의가 필요한 곳에 설치하여 전기스파크 발생 감지를통해 재난이 발생하기 이전 화재위험을 감지하는 방법론 중 하나가 될 수 있다. 제안하는 방법은 음향 센서를 통해 지하공동구 안에서 발생하는 소리들을 수집하고 일정한 길이의 시간 단위 프레임들로 분할한 후 분석하여 전기스파크의 특징 벡터를 도출한다. 전기스파크 감지 모델로는 전기스파크 신호의 지역적 특성을 포착할 수 있도록 2D-CNN 구조를 사용하며 모델에서 출력된 전기 스파크 발생 예측확률을 분할된 단위 프레임 따라 계산하여 융합한다. 이로 인해 높은 정확도의 전기스파크 감지 정밀도를 얻을 수 있으며, 이는 전기 스파크에 의한 화재 이벤트 감지 있어서 효과적인 센싱 기술임을 알 수 있다.

• Korean journal of communication and information
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• v.26
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• pp.157-208
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• 2004

This study explored how television news constructed an issue of the building of a nuclear waste facility on Wido, an issue which displayed a social conflict in the latter half of the year 2003. To do this, this study conducted frame analysis on KBS and MBC main news including national and local ones, broadcasted from 11 July, 2003 to 10 December, 2003. It was found that television news tended to stress violent protests against site designation and social disorder rather than the causes of a conflict and its solutions. Therefore, news reporting excluded fundamental reasons of conflict such as the governmental decision-making process of site designation, geological suitability, safety issue and nuclear energy policy, emphasizing the confrontation and clash between pro and con groups of site designation. This indicates that television news defines an issue of the building of a nuclear waste facility as the local conflict between groups, the police and demonstrators, or neighbors who approve and protest the site designation, not as the national issue of nuclear policy.

• Journal of Internet of Things and Convergence
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• v.8 no.2
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• pp.1-6
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• 2022

This paper presents a regionalized time slotted channel hopping (TSCH) slotframe-based aerial data collection using wake-up radio. The proposed scheme aims to minimize the delay and energy consumption when an unmanned aerial vehicle (UAV) collects data from sensor devices in the large-scale service area. To this end, the proposed scheme divides the service area into multiple regions, and determines the TSCH slotframe length for each region according to the number of cells required by sensor devices in each region. Then, it allocates the cells dedicated for data transmission to the TSCH slotframe using the ID of each sensor device. For energy-efficient data collection, the sensor devices use a wake-up radio. Specifically, the sensor devices use a wake-up radio to activate a network interface only in the cells allocated for beacon reception and data transmission. The simulation results showed that the proposed scheme exhibited better performance in terms of delay and energy consumption compared to the existing scheme.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.37 no.3
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• pp.187-195
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• 2024

This paper presents two-dimensional boundary value problems of the stress-based gradient elasticity within the smoothed finite element method (S-FEM) framework. Gradient elasticity is introduced to address the limitations of classical elasticity, particularly its struggle to capture size-dependent mechanical behavior at the micro/nano scale. The Ru-Aifantis theorem is employed to overcome the challenges of high-order differential equations in gradient elasticity. This theorem effectively splits the original equation into two solvable second-order differential equations, enabling its incorporation into the S-FEM framework. The present method utilizes a staggered scheme to solve the boundary value problems. This approach efficiently separates the calculation of the local displacement field (obtained over each smoothing domain) from the non-local stress field (computed element-wise). A series of numerical tests are conducted to investigate the influence of the internal length scale, a key parameter in gradient elasticity. The results demonstrate the effectiveness of the proposed approach in smoothing stress concentrations typically observed at crack tips and dislocation lines.