• Title/Summary/Keyword: Virtual mass method

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The Qualitative Study on the Evaluation and the Application of 3D scan and virtual try-on technology (3차원 스캔과 가상 착의 기술의 평가와 활용에 관한 질적연구)

  • Choi, Young-Lim;Nam, Yun-Ja
    • Fashion & Textile Research Journal
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    • v.11 no.3
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    • pp.437-444
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    • 2009
  • According to the activation of the fashion electronic commerce, this research investigated the merits and demerits and improvement plan of the 3D virtual try-on technology using the qualitative research method. This research was performed by interview with 70 evaluation group. The evaluation group of 3D virtual try-on was organized and the fit evaluation process by 3D human body scan and the 3D virtual try-on of the i-Fashion technology center were experienced. This study was performed by interview after the actual and virtual try-on about the casual shirt. The convenience and accuracy of measurement, usability in online shopping, body evaluation, complement of sizing system, and body shape management were discovered as merits. The requirement of high accuracy in sizing and avatar, limits of fabric expression, practical limitation by cost, vexatious of measurement garment, differences between real and virtual fittings, personal information leakage risk, and etc were pointed out as demerits. The mass customization, customized garment connected with medical service, humanized avatar, improved fitting report, entertainment, coordination, wardrobe manager were proposed as improvement plan.

3D Visualization Technique Based Tunnel Design (3차원 가시화 기법을 이용한 터널설계)

  • 홍성완;배규진;김창용;서용석;김광염
    • Proceedings of the Korean Geotechical Society Conference
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    • 2002.03a
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    • pp.759-766
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    • 2002
  • In the paper the authors describe the development of ITIS(Intelligent Tunneling Information System) for the Purpose of applying the 3D visualization technique, GIS, AI(Artificial Intelligence) to tunnel design and construction. VR(Virtual Reality) and 3D visualization techniques are applied in order to develope the 3D model of characteristics and structures of ground and rock mass. Database for all the materials related to site investigation and tunnel construction is developed using GIS technique. AI technique such as fuzzy theory and neural network is applied to predict ground settlement, decide tunnel support method and estimate ground and rock mass properties according to tunnel excavation steps. ITIS can help to inform various necessary tunnel information to engineers quickly and manage tunnel using acquired information based on D/B.

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An Optimized Mass-spring Model with Shape Restoration Ability Based on Volume Conservation

  • Zhang, Xiaorui;Wu, Hailun;Sun, Wei;Yuan, Chengsheng
    • KSII Transactions on Internet and Information Systems (TIIS)
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    • v.14 no.4
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    • pp.1738-1756
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    • 2020
  • To improve the accuracy and realism of the virtual surgical simulation system, this paper proposes an optimized mass-spring model with shape restoration ability based on volume conservation to simulate soft tissue deformation. The proposed method constructs a soft tissue surface model that adopts a new flexion spring for resisting bending and incorporates it into the mass-spring model (MSM) to restore the original shape. Then, we employ the particle swarm optimization algorithm to achieve the optimal solution of the model parameters. Besides, the volume conservation constraint is applied to the position-based dynamics (PBD) approach to maintain the volume of the deformable object for constructing the soft tissue volumetric model base on tetrahedrons. Finally, we built a simulation system on the PHANTOM OMNI force tactile interaction device to realize the deformation simulation of the virtual liver. Experimental results show that the proposed model has a good shape restoration ability and incompressibility, which can enhance the deformation accuracy and interactive realism.

Enhancement of the Virtual Metrology Performance for Plasma-assisted Processes by Using Plasma Information (PI) Parameters

  • Park, Seolhye;Lee, Juyoung;Jeong, Sangmin;Jang, Yunchang;Ryu, Sangwon;Roh, Hyun-Joon;Kim, Gon-Ho
    • Proceedings of the Korean Vacuum Society Conference
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    • 2015.08a
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    • pp.132-132
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    • 2015
  • Virtual metrology (VM) model based on plasma information (PI) parameter for C4F8 plasma-assisted oxide etching processes is developed to predict and monitor the process results such as an etching rate with improved performance. To apply fault detection and classification (FDC) or advanced process control (APC) models on to the real mass production lines efficiently, high performance VM model is certainly required and principal component regression (PCR) is preferred technique for VM modeling despite this method requires many number of data set to obtain statistically guaranteed accuracy. In this study, as an effective method to include the 'good information' representing parameter into the VM model, PI parameters are introduced and applied for the etch rate prediction. By the adoption of PI parameters of b-, q-factors and surface passivation parameters as PCs into the PCR based VM model, information about the reactions in the plasma volume, surface, and sheath regions can be efficiently included into the VM model; thus, the performance of VM is secured even for insufficient data set provided cases. For mass production data of 350 wafers, developed PI based VM (PI-VM) model was satisfied required prediction accuracy of industry in C4F8 plasma-assisted oxide etching process.

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A Comparative Study on the Characteristics of Interactivity between Virtual Reality (VR) and Interactive Cinema

  • Jeong, Da-Hee
    • Journal of Multimedia Information System
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    • v.8 no.3
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    • pp.167-174
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    • 2021
  • This paper compares VR cinema with interactive cinema from an interactive perspective to examine cinemas as a new medium. Rather than revealing the difference through this, the focus is on presenting a methodology that understands the cinema in a new environment that is now standing at the starting point. The development of video technology is changing not only the external elements of content but also the internal storytelling method, but the lack of killer content has always been pointed out as a problem compared to the remarkable development of technology. Therefore, it is necessary to specify the characteristics and types of interactions represented by VR (virtual reality) and new media represented by interactive media and to present directions. Therefore, the types and characteristics of interactions were compared with VR film produced in line with the new phenomenon and interactive film . Through this, we would like to present the meaning and value of the new film format from a media perspective.

Predicting the Morton Effect in a Steam Turbine with Sensitivity Vector (민감도 벡터를 이용한 스팀 터빈의 Morton Effect 발생 예측)

  • Donghyun Lee;Byungock Kim;Byungchan Jeon;Junho Suh;Shinhun Kang;Seryong Kim
    • Tribology and Lubricants
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    • v.40 no.2
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    • pp.39-46
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    • 2024
  • The Morton effect (ME) is an instability phenomenon occurring in rotating machineries supported by fluid film bearings and is induced by the thermal deformation of the overhung mass, which is a part of the rotating shaft. Herein, we describe the ME during the high-speed balancing test of a 20 MW class steam turbine. Additionally, to predict the rotating speed at which the ME occurs, we apply the sensitivity vector theory for the steam turbine. During the operation of the steam turbine, we observe a continuous increase in vibration and hysteresis near the rated speed, which is typical of the ME. Increasing the temperature of the lubricating oil supplied to the bearings from 40 to 60℃ suppresses the occurrence of the ME. The rotordynamic analysis for the steam turbine suggests the existence of a mode in which the overhung mass undergoes significant deformation near the rated speed, and we presume that such a mode will increase the occurrence of the ME. The predicted rotating speed of ME occurrence, obtained through the sensitivity vector method, correlates with the test results. Moreover, increasing the temperature of the supplied lubricating oil mitigates the occurrence of ME by reducing the sensitivity between the temperature deviation vector and unbalance mass vector.

A Study on the Support Design for Underground Excavation Based on the Rock-Support Interaction Analysis (암반-지보 거동분석에 의거한 지하굴착 지보설계에 관한 연구)

  • 김혁진;조태진;김남연
    • Tunnel and Underground Space
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    • v.7 no.1
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    • pp.1-12
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    • 1997
  • Engineering rock mass classification is extensively used to determine the reasonable support system throughout the tunneling process in the field. Selection of support system based on the results of engineering rock mass classification is simple and straight-forward. However, this method cannot consider the effect of in-situ stresses, mechanical properties of support material, and support installation time on the behavior or rock-support system To handle the various conditions encountered in the underground excavation sites rock-support system. To handle the various conditions encountered in th eunderground excavation sites rock-support interaction program has been developed. This program can analyze the interaction between rock mass and support materials and also can simulate the tunnel excavation-support insstallation process by controlling the support installation time and the stiffness of support system. Practical applicability of this program was verfied by comparing the results of support design to those from rock mass classification for virtual underground excavation at the drilling site KD-06 in Geoje island.

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Adaptive Mesh Structure for Realtime Paper Crumple Simulation (실시간 종이 구김 시뮬레이션을 위한 적응적 메쉬 구조)

  • Kang, Young-Min
    • Journal of Korea Game Society
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    • v.9 no.4
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    • pp.97-106
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    • 2009
  • In this paper, a realtime approach to the simulation of virtual paper with an adaptive mesh structure is proposed. The proposed method can be applied to arbitrary triangular mesh structures and efficiently produces wrinkles and creases on the paper surface with stable numerical integration and deformation-based mesh refinement. In order to plausibly represent the crumples on the paper object, we employed an adaptive mesh structure with breakable springs. Because the adaptive structure continuously inserts or removes vertices and edges to or from the mesh structure, the conservation of the mass and the momentum should be carefully taken into account for the plausible simulation of the virtual paper. The proposed method produced plausible animation of paper-like thin shell in realtime environments.

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On the Virtual Inertia Coefficient of the Chine-type Ship in Vertical Vibration (Chine형선(型船)의 상하진동(上下振動)에 대(對)한 가상관성계수(假想慣性係數)에 관(關)하여)

  • K.C.,Kim;J.J.,Kim
    • Bulletin of the Society of Naval Architects of Korea
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    • v.9 no.1
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    • pp.1-6
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    • 1972
  • To contribute towards more accurate estimation of the virtual coefficient for the vertical vibration of the chine-type ship, experimentally obtained three-dimensional correction factors, J, of added mass of prismatic beams having cross section shape of hypotrocoid characters, slightly concaved Lewis form and elliptic form are investigated in connection with the applicability of an approximate analytical calculation method compared to that proposed by T. Kumai[6] for the Lewis form cylinders, and synthetically in compared with the experimental works on various cross section shapes of the other type by L.C. Burril et al[8] and the analytical works on the ellipsoid of revolution by F.M. Lewis[1] and J.L. Taylor[2]. The experimental results show that the aforementioned analytical method gives, unlike that for the Lewis form cylinders, considerably larger J-values for the chine-type cylinders, and that the influence of the character of the cross section shape on J-values is not remarkable in practical sense. Finally, considering in synthesis the experimental results on prismatic beams, the Burril's works on palabolic plan form and elliptic plan form, and that the chine-type ship usually has a hull form of transom stern, it is fairly safe to say, at the present stage, that adoptation of the Taylor's J-values will not results in any large error in estimation of the virtual inertia coefficients of the chine-type ships.

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Analysis on Hydrodynamic Force Acting on a Catamaran at Low Speed Using RANS Numerical Method

  • Mai, Thi Loan;Nguyen, Tien Thua;Jeon, Myungjun;Yoon, Hyeon Kyu
    • Journal of Navigation and Port Research
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    • v.44 no.2
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    • pp.53-64
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    • 2020
  • This paper discusses the hydrodynamic characteristics of a catamaran at low speed. In this study, the Delft 372 catamaran model was selected as the target hull to analyze the hydrodynamic characteristics by using the RANS (Reynold-Averaged Navier-Stokes) numerical method. First, the turbulence study and mesh independent study were conducted to select the appropriate method for numerical calculation. The numerical method for the CFD (Computational Fluid Dynamic) calculation was verified by comparing the hydrodynamic force with that obtained experimentally at high speed condition and it rendered a good agreement. Second, the virtual captive model test for a catamaran at low speed was conducted using the verified method. The drift test with drift angle 0-180 degrees was performed and the resulting hydrodynamic forces were compared with the trends of other ship types. Also, the pure rotating test and yaw rotating test proposed by Takashina, (1986) were conducted. The Fourier coefficients obtained from the measured hydrodynamic force were compared with those of other ship types. Conversely, pure sway test and pure yaw test also were simulated to obtain added mass coefficients. By analyzing these results, the hydrodynamic coefficients of the catamaran at low speed were estimated. Finally, the maneuvering simulation in low speed conditions was performed by using the estimated hydrodynamic coefficients.