• 한국복합재료학회:학술대회논문집
• /
• 한국복합재료학회 2001년도 추계학술발표대회 논문집
• /
• pp.191-194
• /
• 2001

A partially coupled thermo-piezoelectric-mechanical triangular finite element model of composite laminates with surface bonded piezoelectric actuators, subjected to externally applied mechanical load, temperature change load, electric field load is developed. The governing differential equations are obtained by applying the principle of free energy and variational techniques. A higher order zigzag theory displacement field is employed to accurately capture the transverse shear and normal effects in laminated composite plates of arbitrary thickness. Nonconforming shape functions by Specht are employed in the transverse displacement variables. Numerical examples demonstrate the accuracy and efficiency of the proposed triangular plate element.

• Structural Engineering and Mechanics
• /
• 제64권3호
• /
• pp.329-337
• /
• 2017

This study concerns the vibrational behavior of multi-walled nested silicon-carbide and carbon nanotubes using the finite element method. The beam elements are used to model the carbon-carbon and silicon-carbon bonds. Besides, spring elements are employed to simulate the van der Waals interactions between walls. The effects of nanotube arrangement, number of walls, geometrical parameters and boundary conditions on the frequencies of nested silicon-carbide and carbon nanotubes are investigated. It is shown that the double-walled nanotubes have larger frequencies than triple-walled nanotubes. Besides, replacing silicon carbide layers with carbon layers leads to increasing the frequencies of nested silicon-carbide and carbon nanotubes. Comparing the first ten mode shapes of nested nanotubes, it is observed that the mode shapes of armchair and zigzag nanotubes are almost the same.

• 대한전기학회:학술대회논문집
• /
• 대한전기학회 1998년도 하계학술대회 논문집 A
• /
• pp.146-148
• /
• 1998

For the shape design of electromagnetic devices using the FEM, the choice of design parameters influence to the success of the optimization process. If the design parameter distribution has a one to one corespondence with finite element model, we can encounter not only serious accuracy problem but also obtain a zigzag shape along the interface. The nodes between those design parameters can be parameterized by interpolating using one among many interpolation methods. The conventional parameterization of design parameters has a limit of application for shape, because design parameters and movable nodes are linearly intepolated. In this paper, using the B-spline curve that use to present any interfaces in computer graphics, the curvilinear parameterization between design parameters and node points is compared with the linear parameterization.

• 대한임베디드공학회논문지
• /
• 제15권6호
• /
• pp.281-287
• /
• 2020

In this paper, we propose a method for estimating a walking direction by which a mobile robots follows a person using TRT (Tensor RT) pose, which is motion recognition based on deep learning. Mobile robots can measure individual movements by recognizing key points on the person's pelvis and determine the direction in which the person tries to move. Using these information and the distance between robot and human, the mobile robot can follow the person stably keeping a safe distance from people. The TRT Pose only extracts key point information to prevent privacy issues while a camera in the mobile robot records video. To validate the proposed technology, experiment is carried out successfully where human walks away or toward the mobile robot in zigzag form and the robot continuously follows human with prescribed distance.

• 대한조선학회논문집
• /
• 제59권3호
• /
• pp.173-182
• /
• 2022

The present study suggests a procedure of establishing a ship dynamics modeling by regression of free-running model test results. The hydrodynamic force and moment of the whole model ship is derived from the low-pass filtered acceleration in the turning circle and zigzag maneuver tests. Force and moment of the propeller and rudder are separated from that of the whole ship to acquire the hull force and moment terms, based on the principles of the component model. The low-pass filter frequency is verified in prior to dynamics modeling, to find the threshold frequency of 2.5 Hz. The dynamics modeling of the hull is compared with the component modeling by captive model tests. Because of strong correlation between sway velocity, yaw angular velocity, and heel angle, each maneuvering coefficient is not able to be validated, but the whole modeling shows good agreement with the captive model tests.

• 한국농공학회지
• /
• 제15권3호
• /
• pp.3096-3106
• /
• 1973

As a link in the chain of antidrought measure, our attempt is made to obtain basic informations on the construction of an infiltration gallary which can be supplied with irrigation water by catching of underground water in small river beds, which is economical, permanent and efficient. The experiment was made, concerning the structure of catchment conduits, by constructing a model sand tank $1.5m{\times}5m{\times}1.5m$ in dimension made of reinforced concrete. Various kinds of measuring equipment were attached to the model tank which contains a set of catchment conduits, each of them was made 30cm in diameter and 60cm in length with the ratio of sectional area to total area of influx holes 10:1, 20:1, 30:1. The average size of influx holes was fixed from 0mm to 10mm, 20mm and 30mm in diameter respectively. Obtained results are as follow; (a) In view of the water catchment capacity, manufacturing cost and the antipressure strength of the catchment conduits, it is the best method to decide the total number of influx holes 20 per sq. meter of each tile surface, and the size of influx holes 20mm in diameter, when the conduits have diameter less than 1m. (b) The greatest factor of safety against external load is to arrange the influx holes in a zigzag manner on the tile surface. The most effective formula of arrangement is $S{\geqq}\sqrt{2gd}$ where: s : spacing of opening row. g : spacing of opening line. d : diameter of influs hole.

• 대한기계학회논문집A
• /
• 제24권7호
• /
• pp.1740-1747
• /
• 2000

Under repeated rolling, initial plastic deformation introduces residual stresses which render the steady cyclic state purely elastic. This is called the process of shakedown. Many studies have been done about the shakedown in semi-infinite half space using calculated Hertizian pressure. In this paper shakedown processes in a shaft are studied by finite element analyses of a two dimensional(plane strain) model with elastic-linear-kinematic-hardening-plastic material subjected to repeated, frictionless rolling contact. Symmetric and non-symmetric pressure distributions are obtained using a simplified model of the bearing-shaft assembly. The rolling contact is simulated by repeatedly translating both pressure distributions along the surface of the shaft. By the influence of the non-symmetric pressure, larger residual radial tensile stress is generated in the immediate subsurface layer, which may make a crack propagate and, the subsurface undergoes a zigzag plastic deformation during the shakedown process, which may lead to a crack initiation.

• 패션비즈니스
• /
• 제4권4호
• /
• pp.41-54
• /
• 2000

The purpose of this study was to investigate various expressions in textile design using CAD and present print design of '01/02 A/W. Four steps were taken in order to achieve this purpose. The first step was to investigate prior research and to analyze textile design methods using CAD. The second step was to study '01/02 A/W fashion trend, especially textile trend. The third step was to design the print design according to textile trend and apply the designed print pattern to real model. The research results are as follows: 1. Textile design is a very important field to help making fashion industry more informative and valuable. 2. Using CAD system in textile design will be very useful and urgent in saving working time and exercising design works. 3. In '01/02 A/W hound's tooth, zigzag, herringbone will be prevalent bold geometric patterns while tartan checks, multi color stripes will be popular too. 4. Textile designs using flower, stripe, checks, dot, abstract pattern were applied to real model, the images of patterns design are as follow, flower pattern-romantic stripe-avantgarde check-cute dotclassic abstract motive-intelligent.

• 한국정보통신학회논문지
• /
• 제10권11호
• /
• pp.2020-2025
• /
• 2006

H.264/AVC는 ITU-T 비디오 코딩 전문가 그룹과 ISO/IEC MPEG 그룹에 의해 제안된 최신 비디오 코딩 표준안이다. 최근 DMB와 멀티미디어 장비들이 비디오 압축 표준으로 H.264/AVC를 채택하고 있다. 본 논문에서는 메모리 사용을 최소화하고, 칩 면적을 최소화할 수 있는 H.264/AVC의 인트라 프레임 디코더를 제안한다. 제안한 인트라 프레임 디코더는 하드웨어 설계 언어인 VHDL로 기술하여 model_sim을 사용하여 시뮬레이션을 수행하였다. 그리고 FPGA칩인 XCV1000E에 다운로드하여 칩 레벨에서 설계된 H.264/AVC의 인트라 프레임 디코더를 검증하였다.

• 정보처리학회논문지A
• /
• 제12A권4호
• /
• pp.321-326
• /
• 2005

본 논문에서는 질점-스프링 모델(mass-spring model)에 기반한 대화형 천 시뮬레이션(interactive cloth simulation) 기법을 제시하며, 특히 소수의 질점들(mass-points)에 상대적으로 강한 힘이 가해졌을 경우 사실적으로 천을 시뮬레이션하는 방법에 초점을 맞추었다. 본 논문에서 제시하는 방법은 소수의 점들에 대해 가해진 힘을 모든 질점들에 분산시킴으로써 의사 실시간(pseudo real-time) 내에 시뮬레이션을 수행하며, 이는 기존의 방법들에 비해 수행속도 면에서 매우 효율적이다. 또한, Provot[9]의 역동역학 방법(inverse dynamic method)을 사용하여 초탄성(super-elasticity) 현상을 해결한 뒤, 인접한 질점 간의 각도를 조정함으로써 초탄성 효과에 의해 발생하는 지그재그(zigzag) 현상을 제거하여 사실적으로 천을 시뮬레이션한다.