• Title/Summary/Keyword: Virtual methods

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A Pen Drawing Method by Tensor-based Strokes Generation (텐서 기반 스트로크 생성에 의한 펜화기법)

  • Shin, Do-kyung;Ahn, Eun-young
    • Journal of Korea Multimedia Society
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    • v.20 no.4
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    • pp.713-720
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    • 2017
  • We present a non-photo realistic pen-ink drawing method for outlining and shading of the input image. Especially, we focus on the detailed illustration of the image of which stroke's direction is important. The pen-ink renderer is an alternative display models user can generate traditional illustration renderings of their photo realistic image. The previously proposed pen drawing methods produce feasible description in general image but it is difficult to express in detail for the sophisticated images that need to consider the direction of stroke for each image region. In order to overcome the disadvantages of the conventional method, a direction vector is extracted from a tensor field and we determine a stroke's direction in consideration of not only an edge area but also a gradient of a surrounding area in the image. For more detailed description for the sophisticated image, we generate white noises based on the light and shade of the input image and determine the direction and length of the stroke by using the tensor field for each generated white noise. The proposed method works particularly well for traditional architectural images where the direction and detailed description of the pen is important.

Computation for Deformation Modes of a Flexible Body in Multibody System using Experimental Modal Analysis (실험적 모드해석을 이용한 다물체계내 유연체의 변형보드 계산)

  • Kim, Hyo-Sig;Kim, Sang-Sup
    • Proceedings of the KSME Conference
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    • 2003.11a
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    • pp.1718-1723
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    • 2003
  • This paper presents a computational method for deformation modes of a flexible body in multibody system from the experimental modal analysis and an efficient method for flexible multibody dynamic analysis by use of the modes. It is difficult to directly use experimental modal parameters in flexible multibody dynamic analysis. The major reasons are that there are many inconsistencies between experimental and analytical modal data and experimental noises are inherent in the experimental data. So two methods, such as, a method for ortho-normalization of experimental modes and the other one for mode expansion, are suggested to gain deformation modes of a flexible body from the experimental modal parameters. Using the virtual work principle, the equation of motion of a flexible body is derived. The effectiveness of the proposed method will be verified in the numerical example of cab vibration of a truck by comparing analysis and test results.

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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.

Dynamic Multi-distributed Web Cluster Group Model for Availability of Web Business (웹 비즈니스의 고가용성을 위한 동적 다중 웹 분산 클러스터 그룹 모델)

  • Lee, Gi-Jun;Park, Gyeong-U;Jeong, Chae-Yeong
    • The KIPS Transactions:PartA
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    • v.8A no.3
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    • pp.261-268
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    • 2001
  • With the rapid growth of the Internet, various web-based businesses are creating a new environment in an imaginary space. However, this expanding Internet and user increase cause an overflow of transmission and numerous subordinate problems. To solve these problems, a parallel cluster system is produced using different methods. This thesis recommends a multi0distribution cluster group. It constructs a MPP dynamic distribution sub-cluster group using numerous low-priced and low-speed systems. This constructed sub-cluster group is then connected with a singular virtual IP to finally serve the needs of clients (users). This multi-distribution cluster group consists of an upper structure based on LVS and a dynamic serve cluster group centered around an SC-server. It conducts the workloads required from users in a parallel process. In addition to the web service, this multi-distribution cluster group can efficiently be utilized for the calculations which require database controls and a great number of parallel calculations as well as additional controls with result from the congestion of service.

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A study on Applicability through Comparison of Weather Data based on Micro-climate with existing Weather Data for Building Performative Design (건물 성능디자인을 위한 미기후 기반 기상데이터의 기존 기상데이터와 비교를 통한 활용 가능성 연구)

  • Kim, Eon-Yong;Jun, Han-Jong
    • KIEAE Journal
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    • v.11 no.6
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    • pp.101-108
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    • 2011
  • The weather data has important role for performative building design. If the data location is close to building site, the result of performative design can be accurate. The data which have used nowadays in Korea are from U.S. Department of Energy (DOE) and Korea Solar Energy Society (KSES) but they cover only several locations in Korea which are 4 in DOE and 11 in KSES and there are opinions which it could be served building design efficiently even if the data are not enough. However the weather data for micro-climate are exist which are Green Building Studio Virtual Weather Station (GBS VWS) and Meteonorm weather data. Each weather data has different generation methods which are TMY2, TRY, MM5, and extrapolation. In this research, the weather date for climate are compared with DOE and KSES to check correlation. The result shows the value of correlation in Dry Bulb Temp. and Dew Point Temp. is around 0.9 so they have high correlation in both but in Wind Speed case the correlation(around 0.2) is not exist. In overall result, the data has correlation with DOE and KSES as the value of correlation 0.648 of GBS VW and 0.656 of Meteonorm. Even if the correlation value is not high enough, the patterns of difference in each weather element are similar in scatter plot.

Generating Artificial Winds for Real-time Applications (실시간 응용을 위한 인위적인 바람의 생성)

  • Lee, Nam-Kyung;Baek, Nak-Hoon;Lee, Jong-Won;Ryu, Kwan-Woo
    • Journal of KIISE:Computer Systems and Theory
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    • v.27 no.8
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    • pp.701-709
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    • 2000
  • Real world wind can be classified into two categories: natural wind and artificial wind. Artificial wind can be generated by human beings, air conditioners, electric fans, etc. In this paper, a model for artificial wind is presented. We also present methods to efficiently calculate the forces applied to the objects under influence of the artificial wind. Our model is designed for real-time applications such as virtual environments. A general wind generating system can be established through integrating our model with previous wind models those are concentrated on the natural wind generation.

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Fault Detection Algorithm of Hybrid electric vehicle using SVDD (SVDD 기법을 이용한 하이브리드 전기자동차의 고장검출 알고리즘)

  • Na, Sang-Gun;Jeon, Jong-Hyun;Han, In-Jae;Heo, Hoon
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • 2011.04a
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    • pp.224-229
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    • 2011
  • In this paper, in order to improve safety of hybrid electric vehicle a fault detection algorithm is introduced. The proposed algorithm uses SVDD techniques. Two methods for learning a lot of data are used in this technique. One method is to learn the data incrementally. Another method is to remove the data that does not affect the next learning. Using lines connecting support vectors selection of removing data is made. Using this method, lot of computation time and storage can be saved while learning many data. A battery data of commercial hybrid electrical vehicle is used in this study. In the study fault boundary via SVDD is described and relevant algorithm for virtual fault data is verified. It takes some time to generate fault boundary, nevertheless once the boundary is given, fault diagnosis can be conducted in real time basis.

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Postmodern Characteristics of the body in Fashion Advertisements (패션광고에 나타난 몸의 포스트모더니즘적 특징)

  • Yeom, Hye-Soo;Yim, Eun-Hyuk
    • Journal of Fashion Business
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    • v.15 no.2
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    • pp.57-70
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    • 2011
  • As a form of media diversified and changed by the development of technology, fashion advertisements have brought a new change in representation of the body. With this transition, the characteristics of the body, which is in an inseparable relationship with fashion, have been dramatically changed in fashion advertisements. In hugely extended media flow, fashion advertisements suggest concepts of the body that are completely different from the past and became the focus in advertisements. Moreover, the body in fashion advertisements involve the symbolisms of social and cultural backgrounds followed by their commercialization. This study analyzes the characteristics of the body in fashion advertisements drawing on the innovative concepts of the body in contemporary society which is essentially different from the past ones; these characteristics are examined as postmodern features. The features are categorized as follows; hyperreal body, virtual body, fragmentization of the body through neologism, reconsideration of naked body, and decentralized body. The postmodern characteristics of the body have changed the boundary, broken traditional concepts and thoughts, and proposed new trends by creating revolutions though diversified media. Rapidly changing media is considered to be further accelerated; this transition highlights the postmodern characteristics of the body in fashion advertisements in more innovative methods.

Flow-induced Vibration Analysis for Cascades with Stator-rotor Interaction and Viscosity Effect (스테이터-로터 상호간섭 및 점성효과를 고려한 케스케이드의 유체유발 진동해석)

  • Oh, Se-Won;Park, Oung;Kim, Dong-Hyun
    • Transactions of the Korean Society for Noise and Vibration Engineering
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    • v.16 no.10 s.115
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    • pp.1082-1089
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    • 2006
  • In this study, advanced computational analysis system has been developed in order to investigate flow-induced vibration(FIV) phenomenon for general stator-rotor cascade configurations. Relative movement of the rotor with respect to stator is reflected by modeling Independent two computational domains. Fluid domains are modeled using the unstructured grid system with dynamic moving and local deforming methods. Unsteady, Reynolds-averaged Wavier-stokes equations with one equation Spalart-Allmaras and two-equation SST ${\kappa}-{\varepsilon}$ turbulence models are solved for unsteady flow problems and also relative moving and vibration effects of the rotor cascade are fully considered. A coupled implicit time marching scheme based on the Newmark integration method is used for computing the governing equations of fluid-structure interaction problems. Detailed vibration responses for different flow conditions are presented and then vibration characteristics are physically investigated in the time domain as computational virtual tests.

Out-of-plane ductile failure of notch: Evaluation of Equivalent Material Concept

  • Torabi, A.R.;Saboori, Behnam;Kamjoo, M.R.
    • Structural Engineering and Mechanics
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    • v.75 no.5
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    • pp.559-569
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    • 2020
  • In the present study, the fracture toughness of U-shaped notches made of aluminum alloy Al7075-T6 under combined tension/out-of-plane shear loading conditions (mixed mode I/III) is studied by theoretical and experimental methods. In the experimental part, U-notched test samples are loaded using a previously developed fixture under mixed mode I/III loading and their load-carrying capacity (LCC) is measured. Then, due to the presence of considerable plasticity in the notch vicinity at crack initiation instance, using the Equivalent Material Concept (EMC) and with the help of the point stress (PS) and mean stress (MS) brittle failure criteria, the LCC of the tested samples is predicted theoretically. The EMC equates a ductile material with a virtual brittle material in order to avoid performing elastic-plastic analysis. Because of the very good match between the EMC-PS and EMC-MS combined criteria with the experimental results, the use of the combination of the criteria with EMC is recommended for designing U-notched aluminum plates in engineering structures. Meanwhile, because of nearly the same accuracy of the two criteria and the simplicity of the PS criterion relations, the use of EMC-PS failure model in design of notched Al7075-T6 components is superior to the EMC-MS criterion.