• Title, Summary, Keyword: modal interaction

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Dam-reservoir-foundation interaction effects on the modal characteristic of concrete gravity dams

  • Shariatmadar, H.;Mirhaj, A.
    • Structural Engineering and Mechanics
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    • v.38 no.1
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    • pp.65-79
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    • 2011
  • Concrete hydraulic structures such as: Dams, Intake Towers, Piers and dock are usually recognized as" Vital and Special Structures" that must have sufficient safety margin at critical conditions like when earthquake occurred as same as normal servicing time. Hence, to evaluate hydrodynamic pressures generated due to seismic forces and Fluid-Structure Interaction (FSI); introduction to fluid-structure domains and interaction between them are inevitable. For this purpose, first step is exact modeling of water-structure and their interaction conditions. In this paper, the basic equation involved the water-structure-foundation interaction and the effective factors are explained briefly for concrete hydraulic structure types. The finite element modeling of two concrete gravity dams with 5 m, 150 m height, reservoir water and foundation bed rock is idealized and then the effects of fluid domain and bed rock have been investigated on modal characteristic of dams. The analytical results obtained from numerical studies and modal analysis show that the accurate modeling of dam-reservoir-foundation and their interaction considerably affects the modal periods, mode shapes and modal hydrodynamic pressure distribution. The results show that the foundation bed rock modeling increases modal periods about 80%, where reservoir modeling changes modal shapes and increases the period of all modes up to 30%. Reservoir-dam-foundation interaction increases modal period from 30% to 100% for different cases.

A Study on Developmental Direction of Interface Design for Gesture Recognition Technology

  • Lee, Dong-Min;Lee, Jeong-Ju
    • Journal of the Ergonomics Society of Korea
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    • v.31 no.4
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    • pp.499-505
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    • 2012
  • Objective: Research on the transformation of interaction between mobile machines and users through analysis on current gesture interface technology development trend. Background: For smooth interaction between machines and users, interface technology has evolved from "command line" to "mouse", and now "touch" and "gesture recognition" have been researched and being used. In the future, the technology is destined to evolve into "multi-modal", the fusion of the visual and auditory senses and "3D multi-modal", where three dimensional virtual world and brain waves are being used. Method: Within the development of computer interface, which follows the evolution of mobile machines, actively researching gesture interface and related technologies' trend and development will be studied comprehensively. Through investigation based on gesture based information gathering techniques, they will be separated in four categories: sensor, touch, visual, and multi-modal gesture interfaces. Each category will be researched through technology trend and existing actual examples. Through this methods, the transformation of mobile machine and human interaction will be studied. Conclusion: Gesture based interface technology realizes intelligent communication skill on interaction relation ship between existing static machines and users. Thus, this technology is important element technology that will transform the interaction between a man and a machine more dynamic. Application: The result of this study may help to develop gesture interface design currently in use.

Structural damping for soil-structure interaction studies

  • Lutes, Loren D.;Sarkani, Shahram
    • Structural Engineering and Mechanics
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    • v.3 no.2
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    • pp.107-120
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    • 1995
  • A soil-structure interaction formulation is used here which is based on consideration of the dynamics of the structure with a free, rather than a fixed, base. This approach is shown to give a quite simple procedure for coupling the dynamic characteristics of the structure to those of the foundation and soil in order to obtain a matrix formulation for the complete system. In fixed-base studies it is common to presume that each natural mode of the structure has a given fraction of critical damping, and since the interaction formulation uses a free-base model, it seems natural for this situation to assign the equal modal damping values to free-base modes. It is shown, though, that this gives a structural model which is significantly different than the one having equal modal damping in the fixed-base modes. In particular, it is found that the damping matrix resulting in equal modal damping values for free-based modes will give a very significantly smaller damping value for the fundamental distortional mode of the fixed-base structure. Ignoring this fact could lead one to attribute dynamic effects to interaction which are actually due to the choice of damping.

Development for Multi-modal Realistic Experience I/O Interaction System (멀티모달 실감 경험 I/O 인터랙션 시스템 개발)

  • Park, Jae-Un;Whang, Min-Cheol;Lee, Jung-Nyun;Heo, Hwan;Jeong, Yong-Mu
    • Science of Emotion and Sensibility
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    • v.14 no.4
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    • pp.627-636
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    • 2011
  • The purpose of this study is to develop the multi-modal interaction system. This system provides realistic and an immersive experience through multi-modal interaction. The system recognizes user behavior, intention, and attention, which overcomes the limitations of uni-modal interaction. The multi-modal interaction system is based upon gesture interaction methods, intuitive gesture interaction and attention evaluation technology. The gesture interaction methods were based on the sensors that were selected to analyze the accuracy of the 3-D gesture recognition technology using meta-analysis. The elements of intuitive gesture interaction were reflected through the results of experiments. The attention evaluation technology was developed by the physiological signal analysis. This system is divided into 3 modules; a motion cognitive system, an eye gaze detecting system, and a bio-reaction sensing system. The first module is the motion cognitive system which uses the accelerator sensor and flexible sensors to recognize hand and finger movements of the user. The second module is an eye gaze detecting system that detects pupil movements and reactions. The final module consists of a bio-reaction sensing system or attention evaluating system which tracks cardiovascular and skin temperature reactions. This study will be used for the development of realistic digital entertainment technology.

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Variation of modal parameters of bridges due to vehicle-bridge interaction (차량-교량 상호작용에 의한 교량 모달 특성의 변화)

  • 권순덕;김철영;장승필
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • pp.420-423
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    • 2003
  • This paper addresses the results of experimental and analytical study on the effects of dynamic interaction between vehicle and bridge on modal properties of bridge. Based on ambient vibration test and vehicle impact test on a bridge, it is found that the natural frequencies of bridge are varied by vehicle passing. Analytical studies for the effects of vehicle position, speed, damping, mass ratio and frequency ratio on bridge-vehicle interaction are carried out using complex eigenvalue analysis and numerical integration in time domain. The results show that vehicle properties except speed cause significant change of natural frequency as well as damping of bridge.

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Modal Analysis of Two Rectangular Plates Coupled with Fluid (유체와 연성된 두 직사각형 평판의 모드 해석)

  • Yoo, Gye-Hyoung;Jeong, Kyeong-Hoon;Lee, Seong-Cheol
    • Proceedings of the KSME Conference
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    • pp.556-561
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    • 2001
  • In order to investigate the vibration characteristics of fluid-structure interaction problem, we modeled two rectangular identical plates coupled with bounded fluid. The fixed boundary condition along the plate edges and an ideal fluid were assumed. An experimental modal analysis in order to extract the modal parameters of the system was performed. Finite element analysis was performed using ANSYS to verify modal parameters and analytic results were compared with experimental results. As a result, comparison of experiment and FEM showed good agreement and the transverse vibration modes, in-phase and out of-phase, were observed alternately in the fluid-coupled system. The effect of distance between two rectangular plates on the fluid-coupled natural frequency was investigated.

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Dynamic characteristics assessment of reactor vessel internals with fluid-structure interaction

  • Je, Sang Yun;Chang, Yoon-Suk;Kang, Sung-Sik
    • Nuclear Engineering and Technology
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    • v.49 no.7
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    • pp.1513-1523
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    • 2017
  • Improvement of numerical analysis methods has been required to solve complicated phenomena that occur in nuclear facilities. Particularly, fluid-structure interaction (FSI) behavior should be resolved for accurate design and evaluation of complex reactor vessel internals (RVIs) submerged in coolant. In this study, the FSI effect on dynamic characteristics of RVIs in a typical 1,000 MWe nuclear power plant was investigated. Modal analyses of an integrated assembly were conducted by employing the fluid-structure (F-S) model as well as the traditional added-mass model. Subsequently, structural analyses were carried out using design response spectra combined with modal analysis data. Analysis results from the F-S model led to reductions of both frequency and Tresca stress compared to those values obtained using the added-mass model. Validation of the analysis method with the FSI model was also performed, from which the interface between the upper guide structure plate and the core shroud assembly lug was defined as the critical location of the typical RVIs, while all the relevant stress intensities satisfied the acceptance criteria.

A Study on the Multi-Modal Browsing System by Integration of Browsers Using lava RMI (자바 RMI를 이용한 브라우저 통합에 의한 멀티-모달 브라우징 시스템에 관한 연구)

  • Jang Joonsik;Yoon Jaeseog;Kim Gukboh
    • Journal of Internet Computing and Services
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    • v.6 no.1
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    • pp.95-103
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    • 2005
  • Recently researches about multi-modal system has been studied widely and actively, Such multi-modal systems are enable to increase possibility of HCI(Human-computer Interaction) realization, enable to provide information in various ways and also enable to be applicable in e-business application, If ideal multi-modal system can be realized in future, eventually user can maximize interactive usability between information instrument and men in hands-free and eyes-free, In this paper, a new multi-modal browsing system using Java RMI as communication interface, which integrated by HTML browser and voice browser is suggested and also English-English dictionary search application system is implemented as example.

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MODAL CHARACTERISTIC ANALYSIS OF THE APR1400 NUCLEAR REACTOR INTERNALS FOR SEISMIC ANALYSIS

  • Park, Jong-Beom;Choi, Youngin;Lee, Sang-Jeong;Park, No-Cheol;Park, Kyoung-Su;Park, Young-Pil;Park, Chan-Il
    • Nuclear Engineering and Technology
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    • v.46 no.5
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    • pp.689-698
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    • 2014
  • Reactor internals are sensitive to dynamic loads such as earthquakes and flow induced vibration. Thus, it is essential to identify the dynamic characteristics to evaluate the seismic integrity of the structures. However, a full-sized system is too large to perform modal experiments, making it difficult to extract data on its modal characteristics. In this research, we constructed a finite element model of the APR1400 reactor internals to identify their modal characteristics. The commercial reactor was selected to reflect the actual boundary conditions. Our FE model was constructed based on scale-similarity analysis and fluid-structure interaction investigations using a fabricated scaled-down model.