• Title/Summary/Keyword: Time history

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Analysis of dynamic behavior for truss cable structures

  • Zhang, Wen-Fu;Liu, Ying-Chun;Ji, Jing;Teng, Zhen-Chao
    • Steel and Composite Structures
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    • v.16 no.2
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    • pp.117-133
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    • 2014
  • Natural vibration of truss cable structures is analyzed based upon the general structural analysis software ANSYS, energy variational method and Rayleigh method, the calculated results of three methods are compared, from which the characteristics of free-vibration are obtained. Moreover, vertical seismic response analysis of truss cable structures is carried out via time-history method. Introducing three natural earthquake waves calculated the results including time-history curve of vertical maximal displacement, time-history curve of maximal internal force. Variation curve of maximal displacement of node along span, and variation curve of maximal internal force of member along span are presented. The results show the formulas of frequencies for truss cable structures obtained by energy variational method are of high accuracy. Furthermore, the maximal displacement and the maximal internal force occur near the 1/5 span point. These provide convenient and simple design method for practical engineering.

Development of Seismic Analysis Model and Time History Analysis for KALIMER-600 (KALIMER-600 지진해석모델 개발 및 시간이력 지진응답해석)

  • Koo, Gyeong-Hoi;Lee, Jae-Han
    • Journal of the Earthquake Engineering Society of Korea
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    • v.11 no.3 s.55
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    • pp.73-86
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    • 2007
  • In this paper, a simple seismic analysis model of the KALIMER-600 sodium-cooled fast reactor selected to be the candidate of the GEN-IV reactor is developed. By using this model, the seismic time history analysis is carried out to investigate the feasibilities of a seismic isolation design. The developed simple seismic analysis model includes the reactor building, reactor system,, IHTS piping system, steam generator, and seismic isolators. The dynamic characteristics of the simple seismic model are verified with the detailed 3-dimensional finite element analysis for each part of the KALIMER-600 system. By using the developed simple seismic model, the seismic time history analyses for both cases of a seismic isolation and non-isolation design are performed for the artificial time history of a SSE (Safe Shutdown Earthquake) 0.3g. From the comparison of the calculated floor response spectrum, it is verified that the seismically isolated KALIMER-600 reactor building shows a great performance of a seismic isolation and assures a seismic integrity.

Dynamic Analysis of a KAERI Channel Type Shear Wall: System Identification, FE Model Updating and Time-History Responses (KAERI 채널형 전단벽체의 동적해석; 시스템판별, FE 모델향상 및 시간이력 응답)

  • Cho, Soon-Ho
    • Journal of the Earthquake Engineering Society of Korea
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    • v.25 no.3
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    • pp.145-152
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    • 2021
  • KAERI has planned to carry out a series of dynamic tests using a shaking table and time-history analyses for a channel-type concrete shear wall to investigate its seismic performance because of the recently frequent occurrence of earthquakes in the south-eastern parts of Korea. The overall size of a test specimen is b×l×h =2500 mm×3500 mm×4500 mm, and it consists of three stories having slabs and walls with thicknesses of 140 mm and 150 mm, respectively. The system identification, FE model updating, and time-history analysis results for a test shear wall are presented herein. By applying the advanced system identification, so-called pLSCF, the improved modal parameters are extracted in the lower modes. Using three FE in-house packages, such as FEMtools, Ruaumoko, and VecTor4, the eigenanalyses are made for an initial FE model, resulting in consistency in eigenvalues. However, they exhibit relatively stiffer behavior, as much as 30 to 50% compared with those extracted from the test in the 1st and 2nd modes. The FE model updating is carried out to consider the 6-dofs spring stiffnesses at the wall base as major parameters by adopting a Bayesian type automatic updating algorithm to minimize the residuals in modal parameters. The updating results indicate that the highest sensitivity is apparent in the vertical translational springs at few locations ranging from 300 to 500% in variation. However, their changes seem to have no physical meaning because of the numerical values. Finally, using the updated FE model, the time-history responses are predicted by Ruaumoko at each floor where accelerometers are located. The accelerograms between test and analysis show an acceptable match in terms of maximum and minimum values. However, the magnitudes and patterns of floor response spectra seem somewhat different because of the slightly different input accelerograms and damping ratios involved.

Advanced On-Demand Multicast Routing Protocol For Multimedia Contents (멀티미디어 컨텐츠를 위하여 개선된 ODMRP)

  • Kim, Do-Yeon;Cho, Jin-Woong;Park, Sung-Kwon
    • The Journal of the Institute of Internet, Broadcasting and Communication
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    • v.8 no.5
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    • pp.13-19
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    • 2008
  • A mobile ad-hoc network routing protocols for transmission of multimedia contents need to have low delay time and to maintain the established route because it should secure quality of service(QoS) of the network. In this paper, the proposed protocol, termed HODMRP (History-based On-Demand Multicast Routing Protocol), is enhanced On-Demand Multicast Routing Protocol (ODMRP) by adding the criterion which is the session history for establishing route. The characteristic of this protocol is that data can be transmitted using the redundant route which is already selected by session history, if it occurs that the route is broken, HODMRP have better Packet Delivery Ratio (PDR) value and lower delay time than ODMRP by the simulation results.

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History of Laryngology (후두학의 역사)

  • Chung, Sung-Min
    • Journal of the Korean Society of Laryngology, Phoniatrics and Logopedics
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    • v.23 no.1
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    • pp.13-17
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    • 2012
  • An understanding of the history of laryngology is both interesting and useful for those in the field so this study attempts to uncover some of the interesting aspects of its history. The oldest reference of laryngology in the Orient is in the medical documents called the "Whangjainaekyung",(황제내경) which was written over a time period between 3000-4000 B.C., and described the laryngeal function of respiration, protection of the airway and phonation. In the West, a drawing that seems to portray a tracheostomy was found in medical tombs in the plains of Saqqara in Egypt. These drawings date from approximately 3600 B.C. A watershed in laryngology occurred when a spanish music professor named Manuel Garcia in first successfully used a mirror to inspect the larynx. Since that time, laryngology has developed relatively quickly and clinical laryngology made it possible by means of a number of favorable developments. Great advances in laryngological diagnosis and treatment has occurred since the 1970s thanks to improvements in technology leading to the introduction of an operating microscope, endoscopes and lasers. Despite our recent advances in laryngology, we still have not achieved uniformly favorable outcomes and there is much that we do not know. Our future promises continued advances in the field of laryngology such as gene therapy to improve wound healing and tissue engineering to allow the recreation of normal mucosa. In this review, I divide the history of the larynx into the past, present and future. In the last section, I described the history of laryngology in Korea briefly.

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Historian Samuel Eliot Morison and Writing History of United States Naval Operations in World War II (해양사가 새뮤얼 엘리엇 모리슨(Samuel Eliot Morison)의 해전사 서술과 그 현대적 의미 - 『제2차 세계대전기 미국 해군 작전사』를 중심으로 -)

  • Kim, Hyun-Seung
    • Strategy21
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    • s.42
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    • pp.53-82
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    • 2017
  • Samuel Eliot Morison (1887-1976) was one of the pre-eminent historians of his generation. He was not only a famous historian at that time, but also was promoted to the rank of Admiral in U.S. Navy Reserve. Fifteen volume History of United States Naval Operations in World War II was published between 1947 and 1962, was not only a comprehensive report on the Navy's projection of power over two oceans, but a classic of historical literature that stands as the definitive treatment of it subject. Although he was fifty-five when war come to America in December 1941. Samuel Eliot Morison was determined to play a role. A professor at Harvard at the time, he joined volunteering for duty in the Navy. An experienced sailor, Professor Morison had earlier sailed that same routes taken by Christopher Columbus while researching his biography, Admiral of the Ocean Sea, which appeared in January 1942 th much acclaim and later got a Pulitzer Prize. Thus Morison plunged into the war, crossing the Atlantic aboard a destroyer. He assumed himself as "Parkman on the sea", tried to follow Parkman's historiographic method, not only participatory history but also literary style. And during writing History of United States Naval Operations in World War II, He emphasized two principles, publicity and objectivity. In terms of publicity, he always worried about who read history and why. In his pamphlet, "History as a Literary Art", he asserted it is useless if readers do not read a history which historians wrote. So he thought historians have forgotten that there is an art of writing of history. Therefore, he built his narratives around brightly rendered visuals and used the present tense to describe actions he witnessed firsthand, he wrote of the U.S. combat in very vividly. But strongly driven by publicity, he sometimes lost his balance in writing the naval history. For instance, the naval history became the focus of criticism for its prejudiced comments about the commanders. Also some reviewers asserted he did not secure the objectivity on writing the naval history. Although he sometimes deliberately torpedoed the objectivity of his work for strengthening publicity, by writing an extensive U.S. naval history, he introduced maritime history and naval history to the public widely. Until in early twentieth century, U.S. historians usually had been focusing their effort to the traditional areas, for example politic, economy, and etc. His intensive effort on the operations of U.S. Navy in World War II aroused a public interest in maritime and naval history. In conclusion, through using literary style and realistic narratives, historian Morison wrote a naval history for all the people which could appealed to the public.

A Study on the Concept of Navigational History (항해사의 개념에 관한 연구)

  • 김성준
    • Journal of the Korean Institute of Navigation
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    • v.21 no.4
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    • pp.93-102
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    • 1997
  • History will be defined as a science on human beings in both space and time(des hommes dans le temps et l'espace). Navigational History is a premise to compose Maritime History. Maritime History is a branch of General History which is classified on the basis of space and will be definded as a branch of history to examine 'inter-realtions between maritime affairs and inland affairs'. Then, what kind of 'go by sea'can be a subject of Navigational History ? A research-subject of Navigational History must be navigation rather than sail or voyage. Because while 'sail' means to 'passive and noncommercial sailing' and voyage means to journeyin a general sense that includes sail and navigation, navigation means to indicate ' to go from one place to another in a ship' adn 'to convoy goods by water'. Then, how can we define Navigation History? Navigational History in a narrow sense is to be a field of studying 'process of development of nautical science and seamanship on the side of History ofScience and Techique, whereas Navigational History in a broad sense is to be a field of analyzing 'effects of historical navigation upon history on the side of General History. On studying Navigational History in a narrow sense, there are signifiacances of disclosing what the development of nautical instruments and arts of navigation have played a role in history. Navigational History in a broad sense is a branch of General History to study effects of historical navigation upon history. In conclusion, the significance of studying Navigation History is to disclose process of developmentof arts of navigation, and on the basis of this study is to reveal how the human elements operate in historical navigation. In short, it should not cease to study Navigational History in a narrow sense, and should enlarge its perspective of research toward Navigational History in a broad sense.

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Proposed Method to Predict Core Inventory history and Operator Time Margin during Small Break Accident (대규모의 냉각재 상실 사고시 노심내 냉각재 양의 추정과 운전원 시간마진 예측을 위해 제안된 방법)

  • Hee Cheon No
    • Nuclear Engineering and Technology
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    • v.15 no.4
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    • pp.219-228
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    • 1983
  • The blowdown history of the TMI-2 accident up to the isolation of the relief valve associated with a small break LOCA is reviewed briefly. An analysis is made to determine what instruments should be added in the core in order to prevent core damage in the case of the TMI-2 accident. With the added instruments a procedure is presented on how to predict the uncovered level of the core and how to calculate operator time margin. Sample calculations are done for the TMI-2 accident to determine the uncovered level and operator time margin. Finally, the map to show the uncovered level of the core and operator time margin is drawn with measurable parameters by the above methods.

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A Study of Temporality of a Critical Discourse on the Modern in the Late Japanese Colonial Period (일제말기 근대비판 담론의 시간성 연구: 세계사·전통·비상시)

  • Ko, Bong-Jun
    • Cross-Cultural Studies
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    • v.23
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    • pp.33-55
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    • 2011
  • In the late Japanese colonial period, from the Sino-Japanese War until the Pacific War, critical discourses on the modern were prevalent in Japan and the Joseon. Despite the absence of a consensus about the specific definition of the modern, most thinkers agreed that the modern was something to be overcome. While some regarded naturalism and capitalism of the West as the essence of the modern, some others named scientism and humanism as the nature of the western modernity. Additionally, some criticized the temporal concept of historicism and brought new meanings of 'tradition' into relief, and some others advocated overcoming 'the West inherent in us'. This study is to consider the temporality of the theory of overcoming the modern focusing on the following three notions-world history, tradition, and emergency-, and examines the antinomy of them. The first notion to consider is 'world history'. The theorists of overcoming the modern, including the Kyoto school, discarded the progressive ideology that had led the Western modern history, and instead introduced 'world history' as a new notion. Although this resulted from the imperialistic embracement of the theories of Ranke, a major positivist historian from Germany, it contained antinomy of remaining in 'history' which was the modern temporal view. The second notion is 'tradition'. While the critical mind of 'world history' brought 'time of world' into question in the context of temporal realization, the notion of 'tradition' was to understand 'time of history' itself as the modern and overcome it. The critical mind of the notion involves the attempts to criticize regarding history as a 'progressive' process and to discover tradition as 'the present past' or 'the eternal present'. However, it also contained antinomy; the 'tradition' here was a notion that was created in the modern times, not passed down from ancient times. The third notion to consider is 'emergency', which was a method to define the present time as a transition period toward a new era, relating to states of war. However, the theorists of overcoming the modern did not regard 'emergency' as a particular time that strayed from normal states, instead they thought is as 'a regularized exceptional state', namely 'a state in which exceptions have become regulations'. However, the notion also contained antinomy since the word 'emergency' connotes abnormality.