• 한국전산구조공학회:학술대회논문집
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• 한국전산구조공학회 1999년도 봄 학술발표회 논문집
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• pp.343-350
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• 1999

Orthotropic steel bridge decks are potentially liable to cause fatigue cracks due to weld defects, residual stresses, and in-plane or out-of-plane stresses. In particular, the cracks propagated through deckplate in longitudinal rib to deckplate joints occur at weld toe and weld root due to stress concentrations. Numerical parametric studies are performed to show the Influence of the parameters on the stress concentration at the connection between the longitudinal rib and the deckplate. The parameters include root gap, toe angle $\theta$, toe radius $\rho$, and weld penetration. This study provides a fundamental point for the improvement of fatigue resistance and the estimation of the fatigue crack propagation in wekded joint details.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2001년도 ICCAS
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• pp.67.5-67
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• 2001

A closed loop system with a linear plant and nonlinearity in the feedback connection is analyzed for its quasi-static orbital stability by a state-space approach. First a periodic orbit is assumed to exist in the loop which is determined by describing function method for the given nonlinearity. This is possible by selecting a proper nonlinearity and a rigorous justification of the describing function method.[1-3, 18, 20]. Then by introducing residual operator, a linear perturbed model can be formulated. Using various transformations like a modified eigenstructure decomposition, periodic-averaging, charge of variables and coordinate transformation, the stability of the periodic orbit, as a solution of harmonic balance, can be shown by investigating a simple scalar function and result of linear algebra. This is ...

• 한국철도학회:학술대회논문집
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• 한국철도학회 2007년도 추계학술대회 논문집
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• pp.1913-1919
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• 2007

Substantive provisions of the concept of an estimation and safety of complex technical systems are envisaged. New problems are assume orientation to use of the formalized methods of an estimation of residual resources of reliability of objects, and also development of other methodological base in creation of complex technical systems that is connected with detailed elaboration of attention to a safety at all stages of creation of systems: from designing until operation. In this connection existing large objects should be provided by the developed systems of engineering monitoring and diagnostics.

• 한국구조물진단유지관리공학회 논문집
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• 제7권2호
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• pp.209-218
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• 2003

The analytical studies included nonlinear finite element analysis of split-tee connection details subjected to axial load and lateral load. A three-dimensional model of the connections between CFT columns and H-beams has been developed. Both initial geometrical imperfections and residual stresses are taken into consideration. A geometrically nonlinear load-displacement analysis of the structure containing the imperfection is then performed, using the Riks method. Analytical results are compared with existing experimental results. Extensive parametric analyses are carried out to investigate the relation of the connections between CFT columns and H-beam to various parameters such as the axial load, column width-thickness ratio, and split-tee thickness.

• Environmental Analysis Health and Toxicology
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• 제12권3_4호
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• pp.67-73
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• 1997

This study was carried out to investigate the contents of heavy metals such as iron, copper, lead, cadmium, magnesium, platium in connection with water pollution in sea weed (dried laver) collected from the west, south, south- west, and east coasts of Korea. The results of the study are as follows; Iron was shown the highest value (1.280ppm) in the wild laver from the south coast. Copper was detected in larger qauntities (0.169 ppm) in green laver than in any other kinds of laver observed in this study. Lead was detected in larger quantities (0.195ppm) in the usual laver and green laver from the south-west coast as compared with the other coasts. Although cadmium and platium was also detected from every kind of laver, the concentrations were not over the allowance of the residual.

• Structural Engineering and Mechanics
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• 제56권3호
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• pp.355-367
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• 2015

This paper deals with a new designed joint system for single-layer spatial structures. As the stability of these structures is greatly influenced by the joint behaviour, the aim of this paper is the characterization of the joint response in bending through Finite Element Method (FEM) analysis using ABAQUS. The behaviour of the joints studied here was influenced by many geometrical factors, such as bolts and plate sizes, distance between bolts and end-plate thickness. The study comprised five models of joints with different values of those parameters. The numerical results were compared to the results of previous experimental tests and the agreement was good enough. The differences between the numerical and experimental initial stiffness are attributed to the simplifications introduced when modelling the bolt threads as well as the presence of residual stresses in the test specimens.

• Journal of information and communication convergence engineering
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• 제5권1호
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• pp.29-34
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• 2007

This paper proposes a MAC protocol for real-time VBR (rt-VBR) services in wireless ATM networks. The proposed protocol is characterized by a contention-based mechanism of the reservation request, a contention-free polling scheme for transferring the dynamic parameters, and a priority scheme of the slot allocation. The design objective of the proposed protocol is to guarantee the real-time constraint of rt-VBR traffic. The scheduling algorithm uses a priority scheme based on the maximum cell transfer delay parameter. The wireless terminal establishes an rt-VBR connection to the base station with a contention-based scheme. The base station scheduler allocates a dynamic parameter minislot to the wireless terminal for transferring the residual lifetime and the number of requesting slots as the dynamic parameters. Based on the received dynamic parameters, the scheduler allocates the uplink slots to the wireless terminal with the most stringent delay requirement. The simulation results show that the proposed protocol can guarantee the delay constraint of rt-VBR services along with its cell loss rate significantly reduced.

• 산업경영시스템학회지
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• 제12권19호
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• pp.31-37
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• 1989

본 논문은 비선형 회귀분석 모델(Nonlinear Regression Models)에서의 추산잔차(Recursive Residuals)를 정의하기 위한 것을 목적으로 한다. 선형 회귀분석 모델(Linear Regression Models)에서는 추산잔차가 우리가 측정할 수 없는 진짜 오차(True Error)와 같은 확률 분포를 갖는데 이의 평균은 0이고 분산은 ${sigma}^2$이다. 그러나 비선형 회귀분석에서는 이와 같은 정확한 분포를 알 수가 없기 때문에, 여러 종류의 잔차들을 연구 검토하고 나아가서 시뮬레이션(Simulation)을 통하여 분석.비교한 뒤 추산잔차를 정의하기로 한다.

• 한국방송∙미디어공학회:학술대회논문집
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• 한국방송∙미디어공학회 2019년도 하계학술대회
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• pp.252-254
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• 2019

본 논문은 합성곱 기반의 Single Shot Multibox Detector(SSD) [1] 의 구조를 이용하여 다양한 스케일의 얼굴들을 잘 검출하도록 하였다. 얼굴 검출은 물체 검출과는 다르게 얼굴의 높이와 너비의 비율이 다소 일정하고 크기가 작은 경우가 많은데, 이에 맞게 얼굴 검출이 용이하도록 anchor의 스케일, 비율, 크기를 변경하였다. 특징점 추출 네트워크는 깊은 네트워크의 최적화를 용이하게 하는 skip connection을 이용한 ResNet-50 [2] 기반을 사용하였다. 다양한 크기, 조명, 환경, 각도의 얼굴들을 포함하는 영상들로 이뤄진 Wider Face[3] 데이터 셋의 easy validation set으로 실험한 결과 0.782과 hard validation set에서 0.611의 average precision을 보였다.

• 한국방송∙미디어공학회:학술대회논문집
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• 한국방송∙미디어공학회 2021년도 추계학술대회
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• pp.106-109
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• 2021

본 논문에서는 입력에 따라 합성곱 레이어 간의 잔차 연결을 변화시키는 동적 잔차 연결을 활용해 고해상도 복원 (Super-resolution) 작업을 위한 경량 네트워크를 설계하는 방법을 제안한다. 먼저, 동적 잔차 연결을 입력에 따라 변화시킬 수 있도록 경량화된 (Lightweight) 모듈을 설계하는 방법을 제안한다. 또한 이렇게 설계한 모듈로부터 얻은 잔차 연결에 대한 정보를 토대로 네트워크를 설계하는 방법을 제시한다. 제안된 방법을 통해 설계된 고해상도 복원 작업을 위한 네트워크는 적은 파라미터로도 입력에 따라 적응적으로 네트워크의 구조를 변화시킬 수 있어 효울적으로 다양한 입력 영상을 처리할 수 있다.