• Title/Summary/Keyword: Initial condition

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Need for Accurate Initial Conditions to Simulate Flexible Structures in Motion

  • Woo, Nelson;Ross, Brant;West, Ryan
    • Transactions of the KSME C: Technology and Education
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    • v.3 no.2
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    • pp.97-106
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    • 2015
  • Flexible structures are often important components of mechanical assemblies in motion. A flexible structure sometimes must go through assembly steps that cause it to be in a pre-stressed condition when in the starting position for operation. A virtual prototype of the assembly must also bring the model of the flexible structure into the same pre-stressed condition in order to obtain accurate simulation results. This case study is presented regarding the simulation of a constant velocity joint, with a focus on the flexible boot. The case study demonstrates that careful definition of the initial conditions of the boot and flexible body contacts yields high-fidelity simulation results.

Innovation Cluster of Indian Software Industry: Is It Evolved or Developed\ulcorner (인도 소프트웨어 산업의 혁신클러스터 형성 과정: 개발인가, 진화인가?)

  • 임덕순
    • Journal of Korea Technology Innovation Society
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    • v.5 no.2
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    • pp.167-188
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    • 2002
  • Summary: This paper analyzes Indian software industry in the perspective of innovation cluster. The research shows that the software industry has been following an upstream clustering process, where the major value activity is expanding from low value product/services to high value product/services. The growth of software industry could be successful because there was appropriate initial condition of Bangalore, such as the availability of high qualified human resources, excellent research institutes, small high-tech companies. The role of government was helpful for the late growth of software industry but not a critical factor for the initial development of the S/W cluster. It is suggested that government should consider the initial condition of a concerned location critically to implement a cluster-type innovation policy.

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A SYUDY ON THE OPTIMAL REDUNDANCY RESOLUTION OF A KINEMATICALLY REDUNDANT MANIPULATOR

  • Choi, Byoung-Wook;Won, Jong-Hwa;Chung, Myung-Jin
    • 제어로봇시스템학회:학술대회논문집
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    • 1990.10b
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    • pp.1150-1155
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    • 1990
  • This paper proposes an optimal redundancy resolution of a kinematically redundant manipulator while considering homotopy classes. The necessary condition derived by minimizing an integral cost criterion results in a second-order differential equation. Also boundary conditions as well as the necessary condition are required to uniquely specify the solution. In the case of a cyclic task, we reformulate the periodic boundary value problem as a two point boundary value problem to find an initial joint velocity as many dimensions as the degrees of redundancy for given initial configuration. Initial conditions which provide desirable solutions are obtained by using the basis of the null projection operator. Finally, we show that the method can be used as a topological lifting method of nonhomotopic extremal solutions and also show the optimal solution with considering the manipulator dynamics.

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Undrained solution for cavity expansion in strength degradation and tresca soils

  • Li, Chao;Zou, Jin-feng;Sheng, Yu-ming
    • Geomechanics and Engineering
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    • v.21 no.6
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    • pp.527-536
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    • 2020
  • An elastic-plastic solution for cavity expansion problem considering strength degradation, undrained condition and initial anisotropic in-situ stress is established based on the Tresca yield criterion and cavity expansion theory. Assumptions of large-strain for plastic region and small-strain for elastic region are adopted, respectively. The initial in-situ stress state of natural soil mass may be anisotropic caused by consolidation history, and the strength degradation of soil mass is caused by structural damage of soil mass in the process of loading analysis (cavity expansion process). Finally, the published solutions are conducted to verify the suitability of this elastic-plastic solution, and the parametric studies are investigated in order to the significance of this study for in-situ soil test.

Rate of Convergence in Inviscid Limit for 2D Navier-Stokes Equations with Navier Fricition Condition for Nonsmooth Initial Data

  • Kim, Namkwon
    • Journal of Integrative Natural Science
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    • v.6 no.1
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    • pp.53-56
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    • 2013
  • We are interested in the rate of convergence of solutions of 2D Navier-Stokes equations in a smooth bounded domain as the viscosity tends to zero under Navier friction condition. If the initial velocity is smooth enough($u{\in}W^{2,p}$, p>2), it is known that the rate of convergence is linearly propotional to the viscosity. Here, we consider the rate of convergence for nonsmooth velocity fields when the gradient of the corresponding solution of the Euler equations belongs to certain Orlicz spaces. As a corollary, if the initial vorticity is bounded and small enough, we obtain a sublinear rate of convergence.

A Study on the Shape Finding and Patterning Procedures for Membrane Structures (막구조의 초기형상 및 재단도 결정알고리즘에 관한 연구)

  • 한상을;이경수;이상주;유용주
    • Proceedings of the Computational Structural Engineering Institute Conference
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    • 1998.10a
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    • pp.298-305
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    • 1998
  • The purpose of this study is to propose the method of determining the initial fabric membrane structures surface and membrane patterning procedures. Tension structure, such as, fabric membrane structures and cable-net, is stabilized by their initial prestress and boundary condition. The process to find initial structural overall shape of tension structures produced by initial prestress called Shape Finding or Shape Analysis. One of the most important factor for the design of membrane structures is to search initial smooth surface, because unlike steel or concrete building elements which resist loads in bending, all tension structure forces are carried within the surface by membrane stress or cable tension. To obtain initial surface of fabric membrane element in large deformation analysis, the membrane element is idealized as cable using a technique with Force-density method. and that result is compared with well-known nonlinear numerical method, such as Newton-raphson method and Dynamic relaxation method. The shape resulting from Force-density method has been dealt with as the initial membrane shape and used patterning procedures.

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The Effect of Visual Cues in the Identification of the English Consonants /b/ and /v/ by Native Korean Speakers (한국어 화자의 영어 양순음 /b/와 순치음 /v/ 식별에서 시각 단서의 효과)

  • Kim, Yoon-Hyun;Koh, Sung-Ryong;Valerie, Hazan
    • Phonetics and Speech Sciences
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    • v.4 no.3
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    • pp.25-30
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    • 2012
  • This study investigated whether native Korean listeners could use visual cues for the identification of the English consonants /b/ and /v/. Both auditory and audiovisual tokens of word minimal pairs in which the target phonemes were located in word-initial or word-medial position were used. Participants were instructed to decide which consonant they heard in $2{\times}2$ conditions: cue (audio-only, audiovisual) and location (word-initial, word-medial). Mean identification scores were significantly higher for audiovisual than audio-only condition and for word-initial than word-medial condition. Also, according to signal detection theory, sensitivity, d', and response bias, c were calculated based on both hit rates and false alarm rates. The measures showed that the higher identification rate in the audiovisual condition was related with an increase in sensitivity. There were no significant differences in response bias measures across conditions. This result suggests that native Korean speakers can use visual cues while identifying confusing non-native phonemic contrasts. Visual cues can enhance non-native speech perception.

The Development of a learning Control Method for the Application to Industrial Robots (로봇트에의 적용을 위한 학습제어 방법 개발)

  • 허경무;원광호
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.1 no.2
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    • pp.49-55
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    • 2000
  • In this paper, we show that our previously proposed second-order iterative learning control method with feedback is more effective and has better convergence performance than the second-order iterative learning control method without feedback, particularly in the case of the existence of initial condition errors. Also the convergence proof of the proposed method is given. And through the simulation result of applying the proposed method to the linear time-varying system, we show that our proposed method has enhanced robustness and stability in case of the existence of initial condition errors.

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A Civilian Reporting Service to Guide Converging Resources for Search and Rescue in Disaster Response

  • Chen, Albert Y.;Han, Sang-Uk;Lee, Sang-Hyun;Pena-Mora, Feniosky
    • Journal of Construction Engineering and Project Management
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    • v.1 no.3
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    • pp.45-51
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    • 2011
  • During disaster response, prioritization of limited resources is one of the most important but challenging tasks. At the same time, it is imperative to timely provide to the rescuers with the adequate heavy equipment to facilitate lifesaving operations. However, supply of high demand equipment is usually insufficient during the initial phase of disaster response, challenging lifesaving operations. At the same time, resources outside of the disaster affected zone converge into the area to assist the response efforts, which is the effect of convergence that often made resource coordination challenging in large scale disasters. Meanwhile, the initial condition of the disaster is usually best known by civilians already at the area before and during impact of the disaster. The knowledge of the civilians is not always received and considered by the responding organizations. With the help of these civilians, critical information such as victim location, infrastructure damage, and risk condition could be better know before any response actions are taken. To efficiently collect information and utilize the converging resources, this paper proposes a geospatial information repository for initial condition reporting and update to guide search and rescue operations and deployment of equipment with safety considerations for the rescuers in large scale disaster response scenarios.

Modeling of Dissolution Potential of Diesel Components (Diesel 용출에 따른 지하수 오염물질의 거동)

  • 김낙경;김현성;염익태
    • Proceedings of the Korean Geotechical Society Conference
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    • 2003.03a
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    • pp.577-584
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    • 2003
  • This study investigated the modeling of dissolution Diesel to estimate the behavior of contaminants in the ground. The modeling based on the initial concentration change considering dissolution potential of pure Diesel and Xylene was performed using VISUAL MODFLOW, and was compared with general modeling ignored the initial concentration change condition.

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