• Title/Summary/Keyword: Response reduction

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Unconscious Response Characteristics of Pupils in the Observation toward to Spatial Image (공간이미지를 향한 주시에 나타난 동공의 무의식적 반응 특성)

  • Kim, Jong-Ha
    • Korean Institute of Interior Design Journal
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    • v.27 no.3
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    • pp.136-144
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    • 2018
  • The purpose of this study is to examined the unconscious response of the pupil in the observation toward the image in the eye-tracking experiments that target on a large complex cultural space. Twenty-five men participated in this experiment and the observation data were analyzed in seconds per minute on watching time. It could examine the unconscious response of information searching in the change of pupil size in the process of observing the space. The results could be defined as following several points. First, it was possible to outline the unconscious response characteristics of pupil by analyzing sudden changes in pupil size as total, cumulative, and individual. The response characteristics using frequency and time can be utilized as the analytical method to examine the degree of interest of spatial components according to the purpose of analysis in the future. Second, according to the over ${\pm}5%$ of cumulative variation rate on the pupil size change, during in the 60 seconds, the continuous pupil dilation was used 25.2 seconds in 8.8 rounds and the pupil reduction was used 18.0 seconds in 7.0 rounds. Third, when the variation rate of ${\pm}5%$ or more was regarded as the sudden changes on pupil size by individual variation, the pupil dilation was 7.2 rounds of 8.6 seconds and pupil reduction was 6.0 seconds in 5.0 rounds. This means that the pupil increases 9.3% in one expansion and decreases -8.5% in the reduction process. As regarding pupil changes as cumulative rate, it appeared high change rate on pupil reduction but it became higher on pupil dilation in individual.

Seismic response of 3D steel buildings with hybrid connections: PRC and FRC

  • Reyes-Salazar, Alfredo;Cervantes-Lugo, Jesus Alberto;Barraza, Arturo Lopez;Bojorquez, Eden;Bojorquez, Juan
    • Steel and Composite Structures
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    • v.22 no.1
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    • pp.113-139
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    • 2016
  • The nonlinear seismic responses of steel buildings with perimeter moment resisting frames (PMRF) and interior gravity frames (IGF) are estimated, modeling the interior connections first as perfectly pinned (PPC), and then as partially restrained (PRC). Two 3D steel building models, twenty strong motions and three levels of the PRC rigidity, which are represented by the Richard Model and the Beam Line Theory, are considered. The RUAUMOKO Computer Program is used for the required time history nonlinear dynamic analysis. The responses can be significantly reduced when interior connections are considered as PRC, confirming what observed in experimental investigations. The reduction significantly varies with the strong motion, story, model, structural deformation, response parameter, and location of the structural element. The reduction is larger for global than for local response parameters; average reductions larger than 30% are observed for shears and displacements while they are about 20% for bending moments. The reduction is much larger for medium- than for low-rise buildings indicating a considerable influence of the structural complexity. It can be concluded that, the effect of the dissipated energy at PRC should not be neglected. Even for connections with relative small stiffness, which are usually idealized as PPC, the reduction can be significant. Thus, PRC can be used at IGF of steel buildings with PMRF to get more economical construction, to reduce the seismic response and to make steel building more seismic load tolerant. Much more research is needed to consider other aspects of the problem to reach more general conclusions.

Optimization for Flow Uniformity on the Selective Catalytic Reduction (SCR) System of a Steam Supply Boiler (열병합 보일러 SCR 장치의 유동 균일화를 위한 최적화 연구)

  • Park, Young-Bin;Jang, Choon-Man
    • Proceedings of the SAREK Conference
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    • 2009.06a
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    • pp.415-420
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    • 2009
  • Selective Catalytic Reduction(SCR) has been used for the reduction of $NO_x$ in a steam supply boiler. Recently, the reduction of $NO_x$ becomes an important research field because of its negative effect on an environment. Shape optimization of circular poles installed in the chamber, which is located in upstream of a SCR, has been performed using response surface method and three-dimensional Navier-Stokes analysis to enhance gas flow uniformity. Three design parameters, diameter, arranging angle and stretching ratio of circular poles, are considered in the present study. Throughout the shape optimization of a circular pole, gas flow uniformity is successfully increased by decreasing local recirculation flow in a square duct chamber. Recirculation flow observed in the corner of the square duct can be reduced by proper installation of a guide vane or a blunt body. Detailed flow characteristics are also analyzed and discussed.

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Coupled buffeting response analysis of long-span bridges by the CQC approach

  • Ding, Quanshun;Chen, Airong;Xiang, Haifan
    • Structural Engineering and Mechanics
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    • v.14 no.5
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    • pp.505-520
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    • 2002
  • Based on the modal coordinates of the structure, a finite-element and CQC (complete quadratic combination) method for analyzing the coupled buffeting response of long-span bridges is presented. The formulation of nodal equivalent aerodynamic buffeting forces is derived based on a reasonable assumption. The power spectral density and variance of nodal displacements and elemental internal forces of the bridge structure are computed using the finite-element method and the random vibration theory. The method presented is very efficient and can consider the arbitrary spectrum and spatial coherence of natural winds and the multimode and intermode effects on the buffeting responses of bridge structures. A coupled buffeting analysis of the Jiangyin Yangtse River Suspension Bridge with 1385 in main span is performed as an example. The results analyzed show that the multimode and intermode effects on the buffeting response of the bridge deck are quite remarkable.

Application of the Seismic Response Reduction Technology for Boramae Deokyo Building Remodeling (보라매 대교빌딩 리모델링을 위한 지진응답 저감기술 적용사례)

  • Park, Young-Mi;Park, Ki-Hong;Jo, Seong-Joon
    • Proceedings of the Korean Institute of Building Construction Conference
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    • 2013.11a
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    • pp.134-136
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    • 2013
  • In general, the seismic retrofit is almost essential to extend and remodel aged buildings. Because domestic seismic design code has been enhanced, seismic performance should be secure for aged building remodeling. Seismic response reduction device (damper) is lately appling to ensure seismic performance. This device is economical efficiency method that can reduce the load to foundation and the range of structural reinforcements, shorten of construction period. New shaped steel damper was applied for extension and remodeling construction for Boramae Deakyo building. As a result, the economy and shortening of construction period was achieved.

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An Experimental Study on the Base Isolation of Equipments using Small-Scale Laminated Rubber Bearings (축소 적층고무베어링을 설치한 시설물의 지반진동 분리에 관한 실험 연구)

  • 민경원
    • Proceedings of the Earthquake Engineering Society of Korea Conference
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    • 1999.10a
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    • pp.351-358
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    • 1999
  • The base-isolation technology is to set up LRB between the base of a building and the ground to protect the building from seismic force. As Korea belongs to the region of moderate or weak seismicity it is more resonable to apply the base-isolation technology of LRB in the field of the response reduction of equipments under machine or transportation vibrations than in the field of seismic response reduction of buildings, In this paper small-scale LRB's designed for the response reduction of equipments are manufactured and tested for thier performance. The shaking table test is conducted to analyze the characteristics of LRB such as the variation of natural frequencies damping ratios and equipments responses.

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A Study on Decision-making Criteria in Industrial Sector for Electric Load Aggregation (수요반응자원으로서 산업용 부하의 매집 우선순위 결정 기준에 관한 연구)

  • Kim, Sung-Yul;Kim, Dong-Min
    • The Transactions of The Korean Institute of Electrical Engineers
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    • v.65 no.6
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    • pp.946-954
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    • 2016
  • Energy industry is undergoing a paradigm shift in customer participation in the smartgrid. Customers traditionally consume electrical power. But nowadays not only do they generate electricity from private distributed generations, they can participate in demand response programs with their negawatt power which means a theoretical unit of power representing an amount of energy saved. Therefore development of decision-making criteria for electric load aggregation becomes a greater consideration as an amount of energy saved from demand response resources increases. This paper proposes load aggregators' decision-making criteria in the industrial sector where it made up the largest portion in demand response portfolio in order to assure reliability performance for demand response resources.

Effect of Hysteretic Models on the Inelastic Design Spectra (비탄성 설계 스펙트럼에 의한 이력 모델의 효과)

  • 한상환;오영훈;이리형
    • Proceedings of the Computational Structural Engineering Institute Conference
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    • 1999.10a
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    • pp.214-224
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    • 1999
  • The design response spectrum has been widely used in seismic design to estimate force and deformation demands of structures imposed by Earthquake Ground Motion (EQGM). Inelastic Design Response Spectra (IDRS) to specify design yielding strength in seismic codes are obtained by reducing the ordinates of Linear Elastic Design Response Spectrum (LEDRS) by strength reduction factor (R). Since a building is designed using reduced design spectrum (IDRS) rather than LEDRS in current seismic design procedures it allows structures behave inelastically during design level EQGM. Inelastic Response Spectra (IRS) depend not only on the characteristics of the expected ground motion at a given site, but also on the dynamic properties and nonlinear characteristics of a structure. However, it has not been explicitly investigated the effect of different hysteretic models on IRS. In this study, the effect of hysteretic models on IRS is investigated.

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Analysis of the Reduction of the Dynamic Response for the CNC 5 Axles Machining Center (CNC 5축 공작기계의 동응답 저감 해석)

  • KIM, Gi Man;CHOI, Seong Dae
    • Journal of the Korean Society of Manufacturing Process Engineers
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    • v.9 no.5
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    • pp.83-89
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    • 2010
  • In this paper, the dynamic response of a CNC 5 Axles machining center was analyzed and then controlled passively by using the dynamic absorber. For the simplification of the theoretical approach, the CNC 5 Axles machining center was modeled as a flexible beam(Bed) having a point mass(Column), two discrete systems(a Table-set and a dynamic absorber). Specifically by using the dynamic absorber, the dynamic response of a Table-set which be caused by the vibration of a flexible beam, was reduced down to the infinitesimal level. The optimal design factors of the dynamic absorber were obtained from the minimization of the cost function. It was found that the natural frequencies of a UT-380 machining center be varied due to the movement of the Table-set. In view of the dynamic response of a Table-set, the larger spring stiffness and mass of the dynamic absorber were found to give the greater reduction.

Design Shear Force Reduction Factor of Upper Structure in Seismic Base-isolated System Considering Response Acceleration Decrement Effect (면진구조의 응답가속도 감소효과를 고려한 상부구조의 설계전단력 저감계수)

  • Chen, Hao;Oh, Sang-Hoon
    • Journal of the Architectural Institute of Korea Structure & Construction
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    • v.35 no.7
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    • pp.165-170
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    • 2019
  • The structural damage caused by earthquake to the upper structure of seismic base-isolated system can be suppressed effectively because it is designed to concentrate the input energy on the seismic isolation floor. Further, the response acceleration of seismic base-isolated system can be greatly reduced compared to the seismic structure because of the long period, which means that the design shear force of the seismic base-isolated system can be reduced appropriately. However, when the design shear force is determined to be reduced, the design stiffness will decrease, and the response acceleration will increase oppositely. Therefore, for finding the extent to which the design shear force of the upper structure can be reduced, this paper considered the seismic base-isolated structure as the analytical model and proposed the design shear force reduction factor of the base-isolated structure through the dynamic response analysis, while considering the decrement effect of response acceleration. The research result shows that the response acceleration of the isolated the upper structure can be reduced by 50%~70% of the seismic structure under the same design conditions, and the design shear force can be reduced by up to 40%. By increasing the design stiffness over to 1.8 times of the original design value, the design shear force can be reduced to the same extent as the response acceleration can be reduced compared to the seismic structure.