• 제목/요약/키워드: Dynamic US

검색결과 455건 처리시간 0.034초

미래주의 관점에서 본 론 아라드의 공간 표현에 관한 연구 (A Study on Futuristic Aspects of Ron Arad's Interior Design)

  • 고자경;심은주
    • 한국실내디자인학회논문집
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    • 제17권4호
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    • pp.50-57
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    • 2008
  • Futurism can be defined as a movement in the early 20th century founded by Italian writer Marinetti apposing to traditional and conservative art. Though its life as a movement seemed to be fairly short, it can be said that the very essence of futurism can be seen whenever there is radical change in our society such as the information revolution. Even though the information revolution has brought us many positive improvements our life including art and design, lately there are also discussions about the defects in our life. Ron Arad may be considered as a designer and artist whose intentions and expressions are very similar to those of futurism. This study investigates concepts, meanings, and expressions of futurism in art history and then those of Ron Arad's shown in interior design projects. By examining selected project examples the author defined that rather than optimistic viewpoints, avant-garde and technological aspects were found to be strong in symbolic qualities. As for expressive qualities, dynamism and continuity appeared to be Ron Arad's unique expressions, very similar to those of futurism on the other hand, purity and temporarily were found less. It is hoped that the study may be a help in better understanding futuristic qualities of Ron Arad, one of the radical and experimental designers of our age.

항만 컨테이너 시뮬레이션을 위한 대규모 3D 가시화 시스템 개발 (A Large-Scale 3D Visualization System for Port Container Terminal Simulation)

  • 옥수열
    • 한국정보통신학회논문지
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    • 제19권1호
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    • pp.119-126
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    • 2015
  • 본 논문에서는 항만컨테이너 운영 모니터링 및 계획 시뮬레이션의 결과를 3차원으로 정적 동적 개체를 포함하는 주변 환경의 거동을 시각적으로 표현하고 실제 작업이 이루어지는 애니메이션을 통해 운영모델을 직관적으로 평가가 가능한 시뮬레이션 가시화 시스템을 제안한다. 제안한 항만 시뮬레이션 가시화 시스템(PSVS)은 객체의 상태를 XML기반으로 설계하여 기존의 항만 운영 시뮬레이션(CATOS)과 상호운용성에 있어서 연동성을 극대화하고 실시간으로 대규모 객체에 대한 애니메이션 표현이 가능하도록 구현하였다. 본 논문에서는 PSVS시스템의 설계 방법에 대해서 설명하고 실험을 통해 PSVS의 타당성을 검토하였다.

승선감 개선을 위한 Anti-Seasickness Bed 개발에 관한 연구 (A Study on the Development of Anti-Seasickness Bed)

  • 김영복;이권순;서진호;최용운;채규훈
    • 동력기계공학회지
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    • 제10권1호
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    • pp.96-101
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    • 2006
  • In ship operation the consequence of roll and pitchingmotion can seriously degrade the performance of mechanical and personnel effectiveness. So many studies for the roll stabilization and trimming control system design have been performed and good results have been achieved where the stabilizing fins, tanks, rudders and flaps are used. However the ultimate objective of such approach should be focused on improving the boarding sensitivity. But there may exist many unsolved problems, for examples, ship control performance degradation and increasing of system complexity. So, the achieved control performance could not give us enough comfortable boarding sensitivity where the residual rolling and pitching motion are main drawbacks. To get rid of these disadvantages, the main hull control systems design approach has been considered using semiactive absorber. In this system, dampers, spring, dynamic dampers and control system with sensors are incorporated. In our system considered in this study, just two motors and control system with sensors are used for the bed. And the control system can be installed on each bed. So, we can control every bed on the specified control objective respectively. Above all, the good advantages of this system are the facts followed from simple idea and usefulness. Of course the structural modifications are needed. Considering disturbances, we design control system and verify the usefulness of developed system from the experimental study.

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하이브리드 방식을 이용한 크레인의 앤티스웨이 제어 (Anti-sway Control of Crane System Using Hybrid Control Method)

  • 박흥수;김환성;박준형;이동훈;김상봉
    • 동력기계공학회지
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    • 제2권1호
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    • pp.67-72
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    • 1998
  • In crane control system, it is required that the travelling time of crane must be reduced as much as possible and there is no the swing of load at the end and starting points. In this paper, we present a hybrid control method which includes two control methods of the optimal regulator and the velocity pattern control in order to realize high performance of the anti-sway. To implement the control algorithm, the dynamic equation is linearlized at an equilibrium point, so that the linear time invariant state equation can be obtained. A 1/10 sized model crane of the usual gantry cranes is made and used to show the applicability of the developed hybrid control method. The effectiveness of developed hybrid control method is proved by experimental results which show us good performance for anti-sway control comparing to conventional velocity pattern control. Practically, it is expected that the proposed control system will make an important contribution to the automatic crane control system of the industrial fields.

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Collective Excitations in Thin K Films on Al(111)

  • Kim, Bong-Ok
    • 한국진공학회:학술대회논문집
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    • 한국진공학회 2000년도 제18회 학술발표회 논문개요집
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    • pp.137-137
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    • 2000
  • The surface collective modes of thin K films deposited on Al(111) have been investigated using frequency dependent photoyield measurements and momentum resolved inelastic electron scattering. Jellium based theoretical calculations have predicted a richer set of features in the thin films than for the surface of a semi-infinite solid because there are th interference between two interfaces (substrate-film and film-vacuum) and heavy damping on the substrate. The use of an optical probe and electron scattering has allowed us to draw a more complete picture of the dynamic screening in thin films. The number, dispersion, damping and optical activity of the collective modes of the thin films have been measured as a function of K film thickness. New overlayer-induced excitations are observed : At qII=0, they correspond to the antisymmetric slab mode and the multipole surface plasmon. At finite qII=0, these modes undergo a transition towards the K multipole and monopole surface plasmons. With increasing coverage, the overlayer excitations turn into the collective modes of semi-infinite K. For a consistent interpretation of photoyield and electron energy loss spectra it is crucial to account for the non-analytic dispersion of the overlayer modes at small parallel wave vectors and for the finite angular resolution of the detector. The observed dispersions confirm predictions based on the time-dependent density functional approach.

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Study of a Hybrid Magnet Array for an Electrodynamic Maglev Control

  • Ham, Chan;Ko, Wonsuk;Lin, Kuo-Chi;Joo, Younghoon
    • Journal of Magnetics
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    • 제18권3호
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    • pp.370-374
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    • 2013
  • This paper introduces an innovative hybrid array consisting of both permanent and electro magnets. It will enable us to develop an active control mechanism for underdamped electro-dynamic suspension (EDS) Maglev systems. The proposed scheme is based on the Halbach array configuration which takes the major technical advantage from the original Halbach characteristics: a strongly concentrated magnetic field on one side of the array and a cancelled field on the opposite side. In addition, the unique feature of the proposed concept only differs from the Halbach array with permanent magnets. The total magnetic field of the array can be actively controlled through the current of the electro-magnet's coils. As a result, the magnetic force produced by the proposed hybrid array can also be controlled actively. This study focuses on the magnetic characteristics and capability of the proposed array as compared to the basic Halbach concept. The results show that the proposed array is capable of producing not only an equivalent suspension force of the basic Halbach permanent magnet array but also a controlled mode. Consequently, the effectiveness of the proposed array confirms that this study can be used as a technical framework to develop an active control mechanism for an EDS Maglev system.

Simulating and evaluating regolith propagation effects during drilling in low gravity environments

  • Suermann, Patrick C.;Patel, Hriday H.;Sauter, Luke D.
    • Advances in Computational Design
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    • 제4권2호
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    • pp.141-153
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    • 2019
  • This research is comprised of virtually simulating behavior while experiencing low gravity effects in advance of real world testing in low gravity aboard Zero Gravity Corporation's (Zero-G) research aircraft (727-200F). The experiment simulated a drill rig penetrating a regolith simulant. Regolith is a layer of loose, heterogeneous superficial deposits covering solid rock on surfaces of the Earth' moon, asteroids and Mars. The behavior and propagation of space debris when drilled in low gravity was tested through simulations and visualization in a leading dynamic simulation software as well as discrete element modeling software and in preparation for comparing to real world results from flying the experiment aboard Zero-G. The study of outer space regolith could lead to deeper scientific knowledge of extra-terrestrial surfaces, which could lead us to breakthroughs with respect to space mining or in-situ resource utilization (ISRU). These studies aimed to test and evaluate the drilling process in low to zero gravity environments and to determine static stress analysis on the drill when tested in low gravity environments. These tests and simulations were conducted by a team from Texas A&M University's Department of Construction Science, the United States Air Force Academy's Department of Astronautical Engineering, and Crow Industries

Methodology of seismic-response-correlation-coefficient calculation for seismic probabilistic safety assessment of multi-unit nuclear power plants

  • Eem, Seunghyun;Choi, In-Kil;Yang, Beomjoo;Kwag, Shinyoung
    • Nuclear Engineering and Technology
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    • 제53권3호
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    • pp.967-973
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    • 2021
  • In 2011, an earthquake and subsequent tsunami hit the Fukushima Daiichi Nuclear Power Plant, causing simultaneous accidents in several reactors. This accident shows us that if there are several reactors on site, the seismic risk to multiple units is important to consider, in addition to that to single units in isolation. When a seismic event occurs, a seismic-failure correlation exists between the nuclear power plant's structures, systems, and components (SSCs) due to their seismic-response and seismic-capacity correlations. Therefore, it is necessary to evaluate the multi-unit seismic risk by considering the SSCs' seismic-failure-correlation effect. In this study, a methodology is proposed to obtain the seismic-response-correlation coefficient between SSCs to calculate the risk to multi-unit facilities. This coefficient is calculated from a probabilistic multi-unit seismic-response analysis. The seismic-response and seismic-failure-correlation coefficients of the emergency diesel generators installed within the units are successfully derived via the proposed method. In addition, the distribution of the seismic-response-correlation coefficient was observed as a function of the distance between SSCs of various dynamic characteristics. It is demonstrated that the proposed methodology can reasonably derive the seismic-response-correlation coefficient between SSCs, which is the input data for multi-unit seismic probabilistic safety assessment.

Currency Valuation, Export Competitiveness, and Firm Profitability: Evidence from Bangladeshi Firm-Level Data

  • CHOI, Sunghee
    • The Journal of Asian Finance, Economics and Business
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    • 제8권1호
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    • pp.61-69
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    • 2021
  • The aim of this paper is to empirically investigate whether and how domestic currency valuation is related to firm-level export competitiveness and profitability by using the unique firm-specific dataset on Bangladeshi nonfinancial firms which have been listed continuously from 2010 to 2018. To achieve the aim of this paper, 63 exporting firms are extracted from a total of 125 firms which have been continuously listed during 2010-2018 and used as the final sample firms. The Pedroni cointegration test reveals that export and import prices of the exporting firms are cointegrated in the short-run as well as long-run. The panel dynamic ordinary least square (DOLS) analysis finds that a firm's export competitiveness is maintained by high import inputs even in the presence of depreciation of Bangladeshi currency against the US dollar. Finally, the DuPont analysis finds that the depreciated Bangladeshi currency enhances an exporter's profitability. Conclusions based on the findings are consistent regardless of exchange rate types, such as, real bilateral exchange rate and nominal or real effective exchange rate indexes. Consequently, the firm-level findings of this investigation suggest that undervalution of home currency is essential for Bangaldesh which is one of the frontier markets in South Asia whose exporting firms are mostly price followers in global markets.

고압 인젝터의 분사율 예측을 위한 경량 모델 개발 (Development of a Lightweight Prediction Model of Fuel Injection Rates from High Pressure Fuel Injectors)

  • 이상권;배규한;;문석수;강진석
    • 한국분무공학회지
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    • 제25권4호
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    • pp.188-195
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    • 2020
  • To meet stringent emission regulations of automotive engines, fuel injection control techniques have advanced based on reliable and fast computing prediction models. This study aims to develop a reliable lightweight prediction model of fuel injection rates using a small number of input parameters and based on simple fluid dynamic theories. The prediction model uses the geometry of the injector nozzle, needle motion data, injection conditions and the fuel properties. A commercial diesel injector and US No. 2 diesel were used as the test injector and fuel, respectively. The needle motion data were measured using X-ray phase-contrast imaging technique under various fuel injection pressures and injection pulse durations. The actual injector rate profiles were measured using an injection rate meter for the validation of the model prediction results. In the case of long injection durations with the steady-state operation, the model prediction results showed over 99 % consistency with the measurement results. However, in the case of short injection cases with the transient operation, the prediction model overestimated the injection rate that needs to be further improved.