• Structural Engineering and Mechanics
• /
• 제46권6호
• /
• pp.853-868
• /
• 2013

The comparison of the effectiveness of artificial neural network (ANN) and linear regression (LR) in the prediction of strain in tie section using experimental data from eight high-strength-self-compact-concrete (HSSCC) deep beams are presented here. Prior to the aforementioned, a suitable ANN architecture was identified. The format of the network architecture was ten input parameters, two hidden layers, and one output. The feed forward back propagation neural network of eleven and ten neurons in first and second TRAINLM training function was highly accurate and generated more precise tie strain diagrams compared to classical LR. The ANN's MSE values are 90 times smaller than the LR's. The correlation coefficient value from ANN is 0.9995 which is indicative of a high level of confidence.

• 자동차안전학회지
• /
• 제6권2호
• /
• pp.5-11
• /
• 2014

Front side member of the front impacted vehicle plays a key role in minimizing the impacting load transferred to the compartment. To perform that required function, axial collapse should be dominant during side member crashing and, prior to designing side member, it is crucial to minimize bending moment occurred at the front end. In this study, for FE model of a SUV front body, front impact analyses were carried to find out bumper stay design which effectively develope axial collapse in the side member. As a previous work, the thickness of side member reinforcement were changed. Next, the inner thickness of bumper stay was increased. Also, the bead shape and location were modified. Final front body model showed much more axial collapsed mode and enhanced crash performance. In addition, a stay of octagon section was adopted and that model exhibited distinctive increase in impact energy absorption.

• 한국통신학회논문지
• /
• 제8권1호
• /
• pp.17-22
• /
• 1983

等方性프라즈마円柱가 軸에 수직인 방향으로 일정한 속도로 운동할 때 Lorentz 변환식, 境界條件에 의해 임의의 角度로 入射하는 平面電磁波에 대한 散亂界, 全散亂斷面績, 散亂電力角度分布, 레이다斷面績을 프라즈마円柱의 운동속도, 平面波의 入射角의 關係를 數式으로 유도하고 入射波가 H波인 경우가 E波보다 散亂界에 영향이 많이 있음을 발견하였다.

• Journal of Astronomy and Space Sciences
• /
• 제14권2호
• /
• pp.355-366
• /
• 1997

This paper presents a comprehensive analytical approach for determining key maneuver parameters associated with the acquisition and maintenance of the ground track for a low-earth orbit. A livearized model relating changes in the drift rate of the ground track directly to changes in the orbital semi-major axis is also developed. The effect of terrestrial atmospheric drag on the semi-major axis is also explored, being quantified through an analytical expression for the decay rate as a function of density. The non-singular Lagrange planetary equations, further simplified for nearly circular orbits, provide the desired relationships between the corrective in-plane impulsive velocity increments and the corresponding effects on the orbit elements. The resulting solution strategy offers excellent insight into the dynamics affecting the timing, magnitude, and frequency of these maneuvers. Simulations are executed for the ground track acquisition and maintenance maneuver as a pre-flight planning and analysis.

• 대한수의학회지
• /
• 제56권3호
• /
• pp.197-200
• /
• 2016

A one-year-old, 3.25 kg intact male Chinchilla cat presented with acute right hind limb paralysis. Diagnostic imaging studies found cardiomegaly with interstitial lung pattern, abnormal mitral valve leaflets without maximum opening at the end of the ventricular diastole and during atrial systole and severe mitral inflow obstruction. Based on these findings and its young age, the case was diagnosed as congenital mitral valve stenosis. Treatment was directed to stabilize clinical conditions related to heart failure, to prevent further formation of thrombus and to relieve pain associated with thromboembolism. After one month of therapy, hind limb motor function was fully recovered.

• 대한의용생체공학회:의공학회지
• /
• 제21권2호
• /
• pp.189-201
• /
• 2000

Mechanical factors in the human body are considered to play a dominant role in low back problems. Various spinal structures. including muscles, act in unison to resist the external load. An estimation of the muscle forces in this structure requires a knowledge of the orientation, location and area of cross-section of the muscles to complete the formulation of a truly three-dimensional mathematical model of the spine. The geometric parameters which are calculated were the line of action, the centroid and physiologic area of cross-section of each muscle as a function of the spinal level. This geometric data were obtained from CT scans of 11 subjects participating in this study.

• 한국통신학회논문지
• /
• 제13권4호
• /
• pp.309-321
• /
• 1988

본 논문에서는 단면(cross section)이 원(circle)인 곡면물체를 처리하는 방법인 G.C표현에 있어서 필요한 축방정식과 반경함수를 구하는 방법을 제안한다. 우선 입력으로 들어온 깊이 데이터에서 clustering을 통해 선형축을 가지고 있는 부분과 비선형축을 가지는 부분을 분리하였으며 각 표면마스크조각(surface mask patch)들의 법선 벡터를 통하여 축상의 점들을 추출하였다. 또한 추출된 축상의 점들이 비선형인 경우 Hermite 곡선으로 축방정식을 표현하였으며 본 논문의 유용성을 실험에 의하여 입증하였다.

• Computers and Concrete
• /
• 제15권2호
• /
• pp.183-198
• /
• 2015

Chloride ingress implies a complex interaction between physical and chemical process, in which heat, moisture and chloride ions transport through concrete cover. Meanwhile, reinforced concrete structure itself undergoes evolution due to variation in temperature, relative humidity and creep effects, which can potentially change the deformation and trigger some micro-cracks in concrete. In addition, all of these process show time-dependent performance with complex interaction between structures and environments. In the present work, a time-dependent behavior of chloride transport in reinforced concrete beam subjected to flexural load is proposed based on the well-known section fiber model. The strain state varies because of stress redistribution caused by the interaction between environment and structure, mainly dominated by thermal stresses and shrinkage stress and creep. Finally, in order to clear the influence of strain state on the chloride diffusivity, experiment test were carried out and a power function used to describe this influence is proposed.

• 한국산업정보학회:학술대회논문집
• /
• 한국산업정보학회 2001년도 춘계학술대회논문집:21세기 신지식정보의 창출
• /
• pp.232-236
• /
• 2001

In this paper, we consider the problem of estimation of average radar cross section (RCS) for Swerling 1 fluctuation model, based on the maximum likelihood (ML) estimation method. In a mathematical development we take into account the event that target strength is lower than detection threshold, or the target is not detected. Our ML estimation for the SWR uses the score function that is the joint probability-pdf of the events and random variables. The solution to the ML estimation reduces to an expression in the from of a contraction mapping. The computational efficiency of the contraction mapping theorem is significant in computing the ML estimation as compared with other root-finding algorithms fur most radar tracking conditions.

• 기술사
• /
• 제16권4호
• /
• pp.4-14
• /
• 1983

when one is designing a continuous bridge with variable cross sections, it is very troublesome to integrate explicitly load terms and various factor under consideration so that it has different moment of inertia at each cross section. In this paper to obtain the influence line of a arbitary-span continuous beam with variable cross sections, the value of some particular function due to a load at any point can be carried out by numerical integration instead of definite integral. The ordinate of the influence line equals the product of the magnitude of the final moment at each support due to unit moment at any support and the load terms due to unit load, measured at the point of application of the load. It is concluded that this method can be easily used to design continuous bridges with arbitary cross sections.