• Title/Summary/Keyword: Virtual mass method

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A Study on Hyper-Reality of Fashion by Work of Art (예술작품을 통해 나타난 패션의 하이퍼리얼리티 연구)

  • Minah, Jung
    • Journal of Fashion Business
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    • v.26 no.5
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    • pp.76-90
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    • 2022
  • The rapid growth and influence of digital technologies have had a profound effect on modern society. Companies and businesses can connect through SNS(social network service accounts). The importance of mass media empowers the creation of virtual images that are more realistic than time and space. Unlike traditional reproduction or imitation, the virtual images created in this way are reproduced in a form that lacks the original inspiration's essence. Jean Baudrillard described this phenomenon as the theory of simulation. Baudrillard argued that imitated simulated images replace reality. He stated that reality is lost under excessive images in modern society. In response, based on an understanding of the theory of hyper-reality that emerged through the late stages of the order of simulacre, this study aimed to analyze modern fashion's method of reproducing hyper-real images and investigate the method's characteristics. This study examined the characteristics of hyper-reality described by Baudrillard and analyzed the method of artistic expression of hyper-reality. Based on this method of expression, reproducibility, following the stages of image simulation, was derived. A specific case applied to fashion was analyzed, and based on the image reproduction method, specific characteristics of hyper-reality characteristics in fashion were obtained. Sixty-four collections were selected, out of which 155 images and 43 brands demonstrated the principles of image transformation.

Nonlinear Adaptive Control of EMS Systems with Mass Uncertainty (무게 변화를 고려한 자기부사열차의 비선형 적응제어기법)

  • Jo, Nam-Hoon;Joo, Sung-Jun;Seo, Jin-Heon
    • The Transactions of the Korean Institute of Electrical Engineers D
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    • v.49 no.10
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    • pp.563-571
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    • 2000
  • In this paper, a nonlinear adaptive control method for an EMS(Electro-Magnetic Suspension) system with mass uncertainty is proposed. Using the coordinate transformation and feedback linearizing control, EMS system has been transformed into the form of parametric strict-feedback system with unknown virtual control coefficients. With this transformed system, tuning functions approach, which is an advanced from of adaptive backstepping, has been applied in order to stabilize the system against mass uncertainty. Computer simulation is also carried out in order to compare the performance of the proposed controller with that of feedback linerizing controller.

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Dynamic Response of a Beam Including the Mass Effect of the Moving Loads (이동 하중의 질량효과를 고려한 보의 동적응답)

  • 최교준;김용철
    • Transactions of the Korean Society of Mechanical Engineers
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    • v.15 no.1
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    • pp.61-68
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    • 1991
  • The system such as railway bridge can be modelled as the restrained beam with intermediate supports. This kind of structures are subject to the moving load, which has a great effect on dynamic stresses and can cause sever motions, especially at high velocities. Therefore, to analyze the dynamic characteristics of the system due to the moving load is very important. In this paper, the governing equation of motion of a restrained beam subjected to the moving load is derived by using the Hamilton's principle. The orthogonal polynomial functions, which are trial functions and satisfying the geometric and dynamic boundary conditions, are obtained through simple procedure. The dynamic response of the system subjected to the moving loads is obtained by using the Galerkin's method and the numerical time integration technique. The numerical tests for various constraint, velocity and boundary conditions were preformed. Furthermore, the effects of mass of the moving load are studied in detail.

Analytical and Experimental Study on Vibration Characteristics for Rectangular Tank Structure Filled with Fluid (사각헝 탱크 구조의 접수 진동 특성에 관한 연구)

  • 최수현;김극수;손성완
    • Transactions of the Korean Society for Noise and Vibration Engineering
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    • v.12 no.3
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    • pp.195-203
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    • 2002
  • In the engine room and the aft part areas of the ship, there exist so many tank structures contacting with fresh water or sea water or oil. If these structures exhibit excessive vibrations during the sea trials, it takes a lot of cost, time and effort to improve vibration situation because the reinforcement work requires emptying the fluid out of the tanks, additional welding and special painting. It is therefore very important to predict a precise vibration characteristics of the tank structures at the design stage, however it is not easy to estimate vibration characteristics of the structures because of difficulties for accurate evaluation of the added (or virtual) mass effect due to the fluid inside the tank. In this paper, numerical and experimental approaches have been performed to present same fundamental data necessary for anti-vibration design of tank structures contacting with fluid, by investigating vibration behaviors of rectangular tank structure for various water depths.

Design and Implementation of a Cloth Simulation System based on Hierarchical Space Subdivision Method (계층적 공간 분할 방법을 이용한 의복 시뮬레이션 시스템의 설계 및 구현)

  • Kim Ju-Ri;Cho Jin-Ei;Joung Suck-Tae;Lee Yong-Ju;Jung Sung-Tae
    • Journal of the Korea Society of Computer and Information
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    • v.9 no.4 s.32
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    • pp.109-116
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    • 2004
  • This paper describes a cloth simulation system for dressing 3D virtual human model with different pieces of clothing. The garments are constructed of cutting patterns seamed together. The system reads a body file and a cutting pattern file and produces a new model dressed with the specified garment by using a physical simulation based on a mass-spring model. For the realistic cloth simulation, it performs collision detection and response between triangles of the 3D human model and the garment. Because the number of triangles of a human model is very large. the collision detection and response requires a lot of time. To overcome this problem, we propose a pruning method which decreases the number of collision detection and response by a space-subdivision method. Experimental results show that the system produces realistic images and makes it possible to sew a garment around a virtual human body in several seconds.

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Parallel Structure Design Method for Mass Spring Simulation (질량스프링 시뮬레이션을 위한 병렬 구조 설계 방법)

  • Sung, Nak-Jun;Choi, Yoo-Joo;Hong, Min
    • Journal of the Korea Computer Graphics Society
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    • v.25 no.3
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    • pp.55-63
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    • 2019
  • Recently, the GPU computing method has been utilized to improve the performance of the physics simulation field. In particular, in the case of a deformed object simulation requiring a large amount of computation, a GPU-based parallel processing algorithm is required to guarantee real-time performance. We have studied the parallel structure design method to improve the performance of the mass spring simulation method which is one of the methods of implementing the deformation object simulation. We used OpenGL's GLSL, a graphics library that allows direct access to the GPU, and implemented the GPGPU environment using an independent pipeline, the compute shader. In order to verify the effectiveness of the parallel structure design method, the mass - spring system was implemented based on CPU and GPU. Experimental results show that the proposed method improves computation speed by about 6,000% compared to the CPU Environment. It is expected that the lightweight simulation technology can be effectively applied to the augmented reality and the virtual reality field by using the design method proposed later in this research.

Optimal Blank Design using Virtual Try-Out Method (가상 트라이 아웃 방법을 이용한 최적 블랭크 설계)

  • Ko, Dae-Lim;Jung, Dong-Won
    • Journal of the Korean Society of Manufacturing Process Engineers
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    • v.7 no.4
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    • pp.31-36
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    • 2008
  • Sheet metal forming has some merits that are less loss of materials in process, less time-consuming and it makes mass product possible. The product produced by sheet metal forming process has high strength compared to the weight and better surface characteristics. Therefore, sheet metal forming process is a lot used in automobiles, aircrafts, electronics and appliances. This paper made the process design for forming Bracket Front Back Frame Lower, determined the blank shape and size using PAM-STAMP, commercial software and evaluated formability. It has been proved that the optimal blank through the result forming analysis has advantage in terms of formability and spring back compared to the rectangular blank.

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An Optimized Model for the Local Compression Deformation of Soft Tissue

  • Zhang, Xiaorui;Yu, Xuefeng;Sun, Wei;Song, Aiguo
    • KSII Transactions on Internet and Information Systems (TIIS)
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    • v.14 no.2
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    • pp.671-686
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    • 2020
  • Due to the long training time and high training cost of traditional surgical training methods, the emerging virtual surgical training method has gradually replaced it as the mainstream. However, the virtual surgical system suffers from poor authenticity and high computational cost problems. For overcoming the deficiency of these problems, we propose an optimized model for the local compression deformation of soft tissue. This model uses a simulated annealing algorithm to optimize the parameters of the soft tissue model to improve the authenticity of the simulation. Meanwhile, although the soft tissue deformation is divided into local deformation region and non-deformation region, our proposed model only needs to calculate and update the deformation region, which can improve the simulation real-time performance. Besides, we define a compensation strategy for the "superelastic" effect which often occurs with the mass-spring model. To verify the validity of the model, we carry out a compression simulation experiment of abdomen and human foot and compare it with other models. The experimental results indicate the proposed model is realistic and effective in soft tissue compression simulation, and it outperforms other models in accuracy and real-time performance.

Control Strategy for Modifiable Bipedal Walking on Unknown Uneven Terrain

  • Lee, Woong-Ki;Chwa, Dongkyoung;Hong, Young-Dae
    • Journal of Electrical Engineering and Technology
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    • v.11 no.6
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    • pp.1787-1792
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    • 2016
  • Previous walking pattern generation methods could generate walking patterns that allow only straight walking on flat and uneven terrain. They were unable to generate modifiable walking patterns whereby the sagittal and lateral step lengths and walking direction can be changed at every footstep. This paper proposes a novel walking pattern generation method to realize modifiable walking of humanoid robots on unknown uneven terrain. The proposed method employs a walking pattern generator based on the 3-D linear inverted pendulum model (LIPM), which enables a humanoid robot to vary its walking patterns at every footstep. A control strategy for walking on unknown uneven terrain is proposed. Virtual spring-damper (VSD) models are used to compensate for the disturbances that occur between the robot and the terrain when the robot walks on uneven terrain with unknown height. In addition, methods for generating the foot and vertical center of mass (COM) of the 3-D LIPM trajectories are developed to realize stable walking on unknown uneven terrain. The proposed method is implemented on a small-sized humanoid robot platform, DARwIn-OP and its effectiveness is demonstrated experimentally.

Dynamic Analysis for Mechanical Systems with Multi-Degree of Freedom under Base Excitation Using Relative Acceleration (상대 가속도를 이용한 기초 가진을 받는 다자유도 기계 시스템의 동적 해석)

  • Lee, Tae Won
    • Journal of the Korean Society of Manufacturing Process Engineers
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    • v.19 no.3
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    • pp.36-41
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    • 2020
  • Mechanical systems installed in transport devices, such as vehicles, airplanes, and ships, are mostly subject to translational accelerations at the joints during operations. This base acceleration excitation has a large influence on the performance of the system, therefore, its response must be well analyzed. However, the existing methods for dynamic analysis of structures have some limitations in use. This study presents a new numerical method using relative acceleration to solve these limitations. If the governing equation of motion is linear and the mass matrix, the damping matrix, and the stiffness matrix are constant over time in the finite element analysis, the proposed method can be applied to the transient behavior analysis and the harmonic response analysis of the structure. Because it is not necessary to introduce a virtual mass and the rigid body motions are removed from the analysis, it is possible to use not only the direct integration method in the time domain but also the mode superposition method to obtain the dynamic responses. This paper demonstrates with three examples how the present method is suitable for the dynamic analysis of a structure with multi-degree of freedom.