• Title/Summary/Keyword: Mechanical interaction

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THERMALLY DRIVEN BUOYANCY WITHIN A HOT LAYER DUE TO SPRINKLER OPERATION

  • Nyankina, K.;F Turan, O.
    • Proceedings of the Korea Institute of Fire Science and Engineering Conference
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    • 1997.11a
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    • pp.625-632
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    • 1997
  • A two-dimensional zone-like model is developed to predict the interaction between hot gas layer and water droplets after sprinkler activation. The model combines the motion equations for each droplet with heat and mass transfer between the gas and water. The results indicate that negative buoyancy in the hot layer can only be obtained if the initial temperature profile is uniform. If an experimental profile Is used instead, positive buoyancy results. This conclusion has been confirmed with experimental data.

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Proposal on the Enhancement of Real-time Processing and Interaction in a Camera-tracked Laser Pointer System (카메라 추적 기반 레이저 포인터 시스템의 실시간 처리와 상호작용 개선을 위한 제안)

  • Lim, Jong-Gwan;Sohn, Young-Il;Sharifi, Farrokh;Kwon, Dong-Soo
    • 한국HCI학회:학술대회논문집
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    • 2008.02a
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    • pp.332-336
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    • 2008
  • For reliable real-time interaction in a camera-tracked laser pointer system, a new idea is proposed and its feasibility is tested in this paper. In order to improve response time in the system and remove useless visual overload, the function of a laser pointer in the system is divided, the Region of Functional Interest is defined and subsequently its new interactions are introduced. Finally the experiments to measure reliability, accuracy, latency and usability are conducted and the results are presented.

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A study of wind turbine power generation and turbine/tower interaction using large eddy simulation

  • Howard, R.J.A.;Pereira, J.C.F.
    • Wind and Structures
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    • v.9 no.2
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    • pp.95-108
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    • 2006
  • Wind turbines are highly complex structures for numerical flow simulation. They normally comprise of a turbine mounted on a tower thus the movement of the turbine blades and the blade/tower interaction must be captured. In addition the ground effect should also be included. There are many more important features of wind turbines and it is difficult to include all of them. A simplified set of features is chosen here for both the turbine and the tower to show how the method can begin to identify the main points connected with wind turbine wake generation and tip vortex tower interaction. An approach to modelling the rotating blades of a turbine is proposed here. The model uses point forces based on blade element theory to model the blades and takes into account their time dependent motion. This means that local instantaneous velocities can be used as a basis for the blade element theory. The model is incorporated into a large eddy simulation code and, although many important features are left out of the model, the velocity/power performance relation is generally of the correct order of magnitude. Suggested improvements to the method are discussed.

Evaluation Study of a Human-sized Bipedal Humanoid Robot Through a Public Demonstration in a Science Museum (과학관에서의 대중 시연을 통한 인간크기 이족보행 휴머노이드 로봇의 평가 연구)

  • Ahn, Tae-Beom;Kang, E-Sok
    • Journal of Institute of Control, Robotics and Systems
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    • v.21 no.9
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    • pp.849-857
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    • 2015
  • Although human-sized bipedal humanoid robots have been developed as the ideal form of human-friendly robots, studies of humanoid robots from the user perspective and of actual interaction between humanoid robots and the public in daily environments are few. This paper presents a long-term public demonstration that encouraged interaction between a humanoid robot and unspecified individuals. We have collected a significant amount of subjective evaluation data from the public by performing a storytelling demonstration that enhanced people's empathy towards the robot. The evaluation model consists of the robot's human friendliness, which involves its impression on humans, interaction with humans, and imitation of human motions and the robot's human appearance which involves gender, age, height, and body type. This study shows that there is no significant difference in human-friendliness between gender groups (male and female), while there is a significant difference between age groups (children and adults). In human appearance, it appears that there is no significant difference between either gender groups or age groups, except for the case of the robot's height.

P-M interaction curve for reinforced concrete columns exposed to elevated temperature

  • Kang, Hyun;Cheon, Na-Rae;Lee, Deuck Hang;Lee, Jungmin;Kim, Kang Su;Kim, Heung-Youl
    • Computers and Concrete
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    • v.19 no.5
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    • pp.537-544
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    • 2017
  • The strength and deformational capacity of slender reinforced concrete (RC) columns greatly rely on their slenderness ratios, while an additional secondary moment (i.e., the $P-{\delta}$ effect) can be induced especially when the RC column members are exposed to fire. To evaluate the fire-resisting performances of RC columns, this study proposed an axial force-flexural moment (i.e., P-M) interaction curve model, which can reflect the fire-induced slenderness effects and the nonlinearity of building materials considering the level of stress and the magnitude of temperature. The P-M interaction model proposed in this study was verified in detail by comparing with the fire test results of RC column specimens reported in literature. The verification results showed that the proposed model can properly evaluate the fire-resisting performances of RC column members.

Individual Employees' Service Failures and Customer Satisfaction with the Firm

  • CHAE, Myoung-Jin
    • Journal of Distribution Science
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    • v.18 no.8
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    • pp.35-45
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    • 2020
  • Purpose: Do close linkages among employees during service encounters always enhance customer satisfaction? Drawing on literature in social psychology, this research argues that under certain circumstances close linkages among employees undermine customer satisfaction. More specifically, this research explores a service failure context and shows that higher task interaction among employees during service encounters leads to higher perceived firm entitativity, resulting in an individual employee's service failure being detrimental to customer satisfaction with the firm. Data and research methodology: A series of experiments using scenarios across different service contexts was used in order to test hypotheses. Data was collected via Amazon Mechanical Turk and the models were tested using Hayes PROCESS. Results: The results show that interactions among employees during service result in 1) lower satisfaction with the firm and 2) lower revisit intentions in the future when there is a service failure by an individual employee. Following the main effects analysis, mediation analysis shows that the effect of employee interaction on customer satisfaction with the firm and revisit intention is mediated by perceived firm entitativity. Implications: By examining contexts where employee interaction may be detrimental to firms, this research provides novel insights on how to manage communications among service employees.

3-Dimensional Static and Dynamic Analysis of Soil-Framework Interaction System (지반-골조구조물 상호작용계의 3차원 정.동적 해석)

  • 서상근;장병순
    • Computational Structural Engineering
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    • v.10 no.2
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    • pp.243-254
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    • 1997
  • When dynamic loads such as mechanical load, wind load, and seismic load, which causing a vibration, acts on the body of the 3-D framework resting on soil foundation, it is required to consider the dynamic behavior of soil-space framework interation system. Thus, this study presents the 3-dimensional soil-interaction system analyzed by finite element method using 4-node plate elements with flexibility, 2-node beam elements, and 8-node brick elements for the purpose of idealizing an actual structure into a geometric shape. The objective of this study is the formulation of the equation for a dynamic motion and the development of the finite element program which can analyze the dynamic behavior of soil-space framework interaction system.

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A Brain-Computer Interface Based Human-Robot Interaction Platform (Brain-Computer Interface 기반 인간-로봇상호작용 플랫폼)

  • Yoon, Joongsun
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.16 no.11
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    • pp.7508-7512
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    • 2015
  • We propose a brain-machine interface(BMI) based human-robot interaction(HRI) platform which operates machines by interfacing intentions by capturing brain waves. Platform consists of capture, processing/mapping, and action parts. A noninvasive brain wave sensor, PC, and robot-avatar/LED/motor are selected as capture, processing/mapping, and action part(s), respectively. Various investigations to ensure the relations between intentions and brainwave sensing have been explored. Case studies-an interactive game, on-off controls of LED(s), and motor control(s) are presented to show the design and implementation process of new BMI based HRI platform.

Experimental Study on Interaction Effect of Darrieus Tidal Stream Turbines (다리우스 조류 터빈의 상호작용 효과에 대한 실험적 연구)

  • Kim, Jihoon;Park, Jin-Soon;Ko, Jin Hwan
    • Ocean and Polar Research
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    • v.41 no.3
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    • pp.193-202
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    • 2019
  • There have been various approaches for efficiency improvement of a Darrieus tidal stream turbine after it was introduced as an alternative of horizontal axis turbines. Among the approaches, the researches on the interaction effect of dual configuration were conducted. In this study, a dual Darrieus turbine with a coupling mechanism was proposed for investigating the interaction effect. Also, the effect of bi-directional tidal stream was analyzed with prototype fabrication, apparatus set-up and experiment conduction in indoor and offshore facilities. As the results of the experiments, the dual turbine in case of counter-rotation and inflow between the turbines improved efficiencies by 9.5% and 11.31%, respectively, as compared to the single turbine. Also, the dual turbine in case of the inflow improved efficiencies by 9.4% and 16.62%, respectively, as compared to that in case of outflow between the turbines which represented the case of 180 degrees change of flow direction after slack water. Therefore, the proposed dual turbine showed the advantage in terms of the efficiency as compared to the single turbine and the effect level of the slack water on the performance of the dual turbine was investigated.

Mechanical Properties of Acrylonitrile Functionalized Emulsion SBR/silica Compounds (아크릴로니트릴이 극성기로 도입된 유화중합 SBR/실리카 컴파운드의 기계적 물성)

  • Kim, Dong-Won;Seo, Byeong-Ho;Kim, Hee-Jeong;Paik, Hyun-Jong;Kang, Jong-Won;Kim, Won-Ho
    • Elastomers and Composites
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    • v.47 no.1
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    • pp.54-64
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    • 2012
  • Acrylonitrile was introduced in the emulsion SBR to increase compatibility between silica and rubber. AN-SBR/silica compounds showed faster vulcanization time and higher delta torque values than SBR 1721/silica compounds because interaction between nitrile group of AN-SBR and silanol group on the silica surface could make hydrogen bond that prevented adsorption of the accelerator on the silica surface, which improved the vulcanization reaction efficiency and enhanced the degree of crosslinking. AN-SBR/silica compound showed higher values in minimum torque than SBR 1721/silica compound during the vulcanization because AN-SBR has higher molecular weight than SBR 1721 in the raw material. When PEG was added to the SBR 1721 and AN-SBR compounds, vulcanization time was faster than SBR 1721 and AN-SBR compounds without PEG because PEG has a large number of ether linkages which show high compatibility with silanol group on the silica surface that prevented the adsorption of the accelerator and the ingredients on the silica surface, which improved the vulcanization reaction efficiency. In the mechanical properties, AN-SBR compounds showed higher modulus values at 100%, 300% than SBR 1721 compounds because interaction between nitrile group of AN-SBR and silanol group on the silica surface enhanced the degree of crosslinking. In the dynamic properties, AN-SBR compounds showed lower tan ${\delta}$ values at $0^{\circ}C$ than SBR 1721 compounds in accordance with the $T_g$ values. AN-SBR compounds showed lower tan ${\delta}$ values at $60^{\circ}C$ than SBR 1721 compounds because interaction between acrylonitrile and silica caused strong filler-rubber interaction that induced low energy dissipation by the filler-filler interaction.