• Title/Summary/Keyword: mass movements

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A study on response analysis of 6-DOF pneumatic vibration isolation table loaded by transient movements of carriage on it (상판 위 질량의 순간적인 움직임에 의해 가진되는 6-자유도 공압제진대의 진동 응답에 대한 연구)

  • Sun, Jong-Oh;Shin, Yun-Ho;Kim, Kwang-Joon
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • 2007.05a
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    • pp.97-102
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    • 2007
  • As environmental vibration requirements on precision equipments get more stringent, use of pneumatic vibration isolators becomes more crucial and, hence, their dynamic performance needs to be further improved. Dynamic behavior of those pneumatic vibration isolation tables is very important to both manufacturer and customer as performance specifications. Together with conventional transmissibility, transient response characteristics are another critical performance index especially when movements of components, e.g., x-y tables, of the precision equipments are very dynamic. In this paper, analysis on transient response of a pneumatic vibration isolation table loaded by a mass moving on it is presented. This is a conventional dynamics problem on a rigid body with 6 degree of freedom and a mass with another degree of freedom. How to obtain transient responses of the isolation table is described when the movements of the mass are prescribed relative to the table.

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A Study on Response Analysis of 6-DOF Pneumatic Vibration Isolation Table Loaded by Transient Movements of Carriage on It (상판 위 질량의 순간적인 움직임에 의해 가진되는 6-자유도 공압제진대의 진동 응답에 대한 연구)

  • Sun, Jong-Oh;Shin, Yun-Ho;Kim, Kwang-Joon
    • Transactions of the Korean Society for Noise and Vibration Engineering
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    • v.17 no.6 s.123
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    • pp.515-523
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    • 2007
  • As environmental vibration requirements on precision equipments get more stringent, use of pneumatic vibration isolators becomes more crucial and, hence, their dynamic performance needs to be further improved. Dynamic behavior of those pneumatic vibration Isolation tables is very important to both manufacturer and customer as performance specifications. Together with conventional transmissibility, transient response characteristics are another critical performance index especially when movements of components, e.g., x-y tables, of the precision equipments are very dynamic. In this paper, analysis on transient response of a pneumatic vibration isolation table loaded by a mass moving on it is presented. This is a conventional dynamics problem on a rigid body with 6 degree of freedom and a mass with another degree of freedom. How to obtain transient responses of the isolation table is described when the movements of the mass are prescribed relative to the table.

Application of Time Domain Reflectometry to the Monitoring or Rock Mass Deformation with Coaxial Cable (동축 케이블을 이용한 시간영역 반사법의 암반변위 계측에의 적용)

  • 정슬람;정소걸;정현기;박철환;박철환;이희근
    • Tunnel and Underground Space
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    • v.6 no.4
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    • pp.306-315
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    • 1996
  • This paper presents an application of the TDR(Time Domain Reflectometry) to the monitoring of the deformation of rock mass with grouted coaxial cables through laboratory tests. The grouted cable can easily deform together with the rock mass movements, and the deformed cable loses its original capacitance and the reflected waveform produced along the deformed cable consequently represents a change of voltage pulse. Therefore, it is possible to monitor the deformation of rock mass by measuring the changes in these reflection signatures. Shear test of the cemented mortar containing a specimen of coaxial cable showed that the shear deformation correlated linearly with the reflection coefficient, so the TDR was effective to monitor the displacement of the rock mass. Bending test were carried out in order to determine the influence of the crooked cables on the monitoring of rock mass movements. Controlled cirmping and shearing test upon a cable of 50 m long, 12.7 mm diameter showed not only the fact that the reflection amplitudes decreased as the cable length increased but also the proper crimping depth, width and interval between two adjacent crimps. Two coaxial cables-one 100 m long and other 175m long-were installed and grouted into the separate boreholes drilled in a sedimentary formation. The behavior of the cable was monitored with metallic TDR cable tester to measure rock mass deformation based on the interpretative techniques developed through laboratory tests.

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Adorno's critique of the possibility of fascist violence in popular movements (대중운동의 파시즘적인 폭력의 가능성과 그에 대한 아도르노의 비판)

  • Kim, Jin-ae
    • Journal of Korean Philosophical Society
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    • v.144
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    • pp.141-166
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    • 2017
  • Adorno's most important criticism in popular movement is the identity of revolutionary leaders and followers. The identification process has three characteristics. The first characteristic is to create a sense of solidarity within the group by creating an image more real than the antagonist and ensuring the distinction between the enemy and the comrades. Individual entities that resist the mass created by the sense of solidarity disappear, and only the subject identified with the group exists. The second characteristic is to present an optimistic utopia, which makes the public believe that salvation comes from transcendent values. This mass movement also leads to criticism of other groups or people who are deemed off-limits to their own solidarity. The third characteristic is that the public, whose individual subject disappears through the narcissism-based public hypnotic state, is identified with the conductors, and forces other subjects to hypnotize themselves. The purpose of this paper is to examine how Adorno criticizes the fascist violence of mass movements and analyze what this suggests about the task of mass movements.

Vibration Analysis of Space Structure with Retractable Roof (개폐식 지붕구조의 움직임에 대한 공간구조물의 진동해석)

  • Kim, Gee-Cheol;Kang, Joo-Won;Kim, Hyun-Su
    • Journal of Korean Association for Spatial Structures
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    • v.11 no.1
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    • pp.113-120
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    • 2011
  • Retractable roof system is one of the special feature in stadium or complex structure. And this retractable roof system makes possible to use spacial structure all-weather. This retractable roof system is able to classified into overlapping, parallel movement and folding system. Moving load, impact load, inertial or braking loads, these dynamic loads induced by movements of retractable roof system. So it is necessary to analysis of spacial structures are subjected to these dynamic loads. Dynamic loads that are induced by the retractable roof movements can be applied to moving mass method or moving force method. But, moving force method is appropriate because the retractable roof movements is slow relatively. In this paper, new application method of moving forces induced by the retractable roof movements is proposed. And vibration analysis of spacial structures are executed by using the proposed method. This proposed equivalent moving force can be easily applied to spacial structure that is subjected to dynamic loads induced by movement of the retractable roof system.

Excavation and Building Damage Assessment - Fundamentals (지반굴착과 주변 구조물 손상평가 - 기본개념)

  • 유충식
    • Proceedings of the Korean Geotechical Society Conference
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    • 2002.03a
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    • pp.263-270
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    • 2002
  • During deep excavation, changes in the state of stress in the ground mass around the excavation and subsequent ground losses inevitably occur. These changes in the stress and ground losses are reflected on surrounding ground in the form of ground movements, which eventually Impose strains onto nearby structures through translation, rotation, distortion, and possibly damage. A substantial portion of the cost of deep excavations in urban environments is, therefore, devoted to prevent ground movements. Prediction of ground movements and assessment of the risk of damage to adjacent structures has become an essential part of the planning, design, and construction of a deep excavation project in the urban environments. This paper presents excavation-induced ground movement characteristics as well as important issues related to excavation-induced building damage assessment.

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Characteristics of the Mass Soil Movement Events (산지(山地)의 Mass Soil Movement 현상(現象)의 몇 가지 특성(特性))

  • Woo, Bo-Myong
    • Journal of Korean Society of Forest Science
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    • v.15 no.1
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    • pp.49-60
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    • 1972
  • During the two days of August 18, 19 of 1972, there was an unusually large number of mass soil movements resulting from severe storms in northeastern Ansong-chon Watershed. The study had several conclusions in connection with relationship between mass soil movement events and certain causing factors such as geology, soil, forest types, degree and profile of slopes, and other geomorphological features. Discussed on the forms and types of the movements including its sizes. Perhaps one of the most important problems facing the Preventive Soil Conservation is to determine the extent of critical conditions of mass soil movement events. Some results of the study will be enough to contribute for interpretation of the problems in this field.

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Implementation of nonlinear two-mass vocal folds digital model (성대의 비선형 2-mass 디지털 모델 구현)

  • Lee, Hui-Sung;Chung, Myung-Jin
    • Proceedings of the KIEE Conference
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    • 2004.11c
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    • pp.9-11
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    • 2004
  • The vocal folds play an important role to produce glottal pulse which is an essential factor of phonation. There have been some models which implement the vocal folds' dynamics, such as one-mass model, two-mass model, multi-mass model and ribbon model. Among them, this paper uses nonlinear two-mass model, which is simple structure and produces similarly real glottal pulses and vocal folds' vibration, to realize vocal folds digital model. The pattern of movements in vocal folds will be shown in this paper by using vocal folds digital model. It will be verified how initial position of vocal folds. variation of tension and change of lung pressure influences vibration and glottal pulses.

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John Ruskin and Herman Muthesius - A Comparative Study on the Architectural Theories of the Early Modern Movements in Britain and Germany - (근대건축 형성기 영국과 독일의 건축이론 비교 연구 -러스킨과 무테지우스의 이론을 중심으로-)

  • Kim, Bong-Ryol
    • Journal of architectural history
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    • v.1 no.2 s.2
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    • pp.116-136
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    • 1992
  • Architectural essence of John Ruskin's discourse can resolve itself into natural beauty, craftmanship, and truth in structure, surface, and process. His theories became disciplines of modern English school, Art and Craft and Free architecture, in aspects of organic architecture, morality, and rationality. These concepts disseminated continental Art Nouveau and also became it's basic principles. But his empirical theories hated use of machine, and should find a ideal model in medieval romanticism of Gothic. Anti-machine, as a instictive guideline of English modern architecture, couldn't cope with the industrialization of 20th century, and Gothic revival interfered with creating a new style. Muthesius' discourses were taught by the power of group movements and modern concept of form in English school, originally by Ruskin. But he accepted the potentiality of machine and mass production, and stressed creating the new German style suitable with machine. With the progress of Deutscher Werkbund, his theories were advanced to 'quality' connected with craftmanship, to discourse on mechanical 'form', and lastly to 'standardization and type' for mass production. Mechanical functionalism of Muthesius and DWB were sophiscated and handed down to Bauhaus, and then finally helped establishment of the Modern Architecture and Internationalism. Both English and German modern architecture owed their contribution as well as limitation to Ruskin and Muthesius as theorists. Through this comparative study, we can see the priority of theory to practice, the theoretical justification based on insight for its society and future, and the practical character of theory itself.

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