• 제목/요약/키워드: dynamic symmetry

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Behavior of Truss Railway Bridge Using Periodic Static and Dynamic Load Tests (주행 열차의 정적 및 동적 재하시험 계측 데이터를 이용한 트러스 철도 교량의 주기적 거동 분석)

  • Jin-Mo Kim;Geonwoo Kim;Si-Hyeong Kim;Dohyeong Kim;Dookie Kim
    • Journal of the Korea institute for structural maintenance and inspection
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    • v.27 no.6
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    • pp.120-129
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    • 2023
  • To evaluate the vertical loads on railway bridges, conventional load tests are typically conducted. However, these tests often entail significant costs and procedural challenges. Railway conditions involve nearly identical load profiles due to standardized rail systems, which may appear straightforward in terms of load conditions. Nevertheless, this study aims to validate load tests conducted under operational train conditions by comparing the results with those obtained from conventional load tests. Additionally, static and dynamic structural behaviors are extracted from the measurement data for evaluation. To ensure the reliability of load testing, this research demonstrates feasibility through comparisons of existing measurement data with sensor attachment locations, train speeds, responses between different rail lines, tendency analysis, selection of impact coefficients, and analysis of natural frequencies. This study applies to the Dongho Railway Bridge and verifies the applicability of the proposed method. Ten operational trains and 44 sensors were deployed on the bridge to measure deformations and deflections during load test intervals, which were then compared with theoretical values. The analysis results indicate good symmetry and overlap of loads, as well as a favorable comparison between static and dynamic load test results. The maximum measured impact coefficient (0.092) was found to be lower than the theoretical impact coefficient (0.327), and the impact influence from live loads was deemed acceptable. The measured natural frequencies approximated the theoretical values, with an average of 2.393Hz compared to the calculated value of 2.415Hz. Based on these results, this paper demonstrates that for evaluating vertical loads, it is possible to measure deformations and deflections of truss railway bridges through load tests under operational train conditions without traffic control, enabling the calculation of response factors for stress adjustments.

Dynamic Response of Tension Leg Platform (Tension Leg Platform의 동적응답에 관한 연구)

  • Yeo, Woon Kwang;Pyun, Chong Kun
    • KSCE Journal of Civil and Environmental Engineering Research
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    • v.5 no.1
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    • pp.21-30
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    • 1985
  • The tension leg platform (TLP) is a kind of compliant structures, and is also a type of moored stable platform with a buoyancy exceeding the weight because of having tensioned vertical anchor cables. In this paper, among the various kinds of tension leg structures, Deep Oil Technology (DOT) TLP was analyzed because it has large-displacement portions of the immersed surface such as vertical corner pontoons and small-diameter elongated members such as cross-bracing. It also has results of hydraulic model tests, comparable with theorectical analysis. Because of the vertical axes of symmetry in the three vertical buoyant legs and because there are no larger horizontal buoyant members between these three vertical members, it was decided to develop a numerical algorithm which would predict the dynamic response of the DOT TLP using the previously developed numerical algorithm Floating Vessel Response Simulation (FVRS) for vertically axisymmetric bodies of revolution. In addition, a linearized hydroelastic Morison equation subroutine would be developed to account for the hydrodynamic pressure forces on the small member cross bracing. Interaction between the large buoyant members or small member cross bracings is considered to be negligible and is not included in the analysis. The dynamic response of the DOT TLP in the surge mode is compared with the results of the TLP algorithm for various combinations of diffraction and Morison forces and moments. The results which include the Morison equation are better than the results for diffraction only. This is because the vertically axisymmetric buoyant members are only marginally large enough to consider diffractions effects. The prototype TLP results are expected to be more inertially dominated.

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A Pipelined Parallel Optimized Design for Convolution-based Non-Cascaded Architecture of JPEG2000 DWT (JPEG2000 이산웨이블릿변환의 컨볼루션기반 non-cascaded 아키텍처를 위한 pipelined parallel 최적화 설계)

  • Lee, Seung-Kwon;Kong, Jin-Hyeung
    • Journal of the Institute of Electronics Engineers of Korea SD
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    • v.46 no.7
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    • pp.29-38
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    • 2009
  • In this paper, a high performance pipelined computing design of parallel multiplier-temporal buffer-parallel accumulator is present for the convolution-based non-cascaded architecture aiming at the real time Discrete Wavelet Transform(DWT) processing. The convolved multiplication of DWT would be reduced upto 1/4 by utilizing the filter coefficients symmetry and the up/down sampling; and it could be dealt with 3-5 times faster computation by LUT-based DA multiplication of multiple filter coefficients parallelized for product terms with an image data. Further, the reutilization of computed product terms could be achieved by storing in the temporal buffer, which yields the saving of computation as well as dynamic power by 50%. The convolved product terms of image data and filter coefficients are realigned and stored in the temporal buffer for the accumulated addition. Then, the buffer management of parallel aligned storage is carried out for the high speed sequential retrieval of parallel accumulations. The convolved computation is pipelined with parallel multiplier-temporal buffer-parallel accumulation in which the parallelization of temporal buffer and accumulator is optimize, with respect to the performance of parallel DA multiplier, to improve the pipelining performance. The proposed architecture is back-end designed with 0.18um library, which verifies the 30fps throughput of SVGA(800$\times$600) images at 90MHz.

Optimal Design for Marker-assisted Gene Pyramiding in Cross Population

  • Xu, L.Y.;Zhao, F.P.;Sheng, X.H.;Ren, H.X.;Zhang, L.;Wei, C.H.;Du, L.X.
    • Asian-Australasian Journal of Animal Sciences
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    • v.25 no.6
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    • pp.772-784
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    • 2012
  • Marker-assisted gene pyramiding aims to produce individuals with superior economic traits according to the optimal breeding scheme which involves selecting a series of favorite target alleles after cross of base populations and pyramiding them into a single genotype. Inspired by the science of evolutionary computation, we used the metaphor of hill-climbing to model the dynamic behavior of gene pyramiding. In consideration of the traditional cross program of animals along with the features of animal segregating populations, four types of cross programs and two types of selection strategies for gene pyramiding are performed from a practical perspective. Two population cross for pyramiding two genes (denoted II), three population cascading cross for pyramiding three genes(denoted III), four population symmetry (denoted IIII-S) and cascading cross for pyramiding four genes (denoted IIII-C), and various schemes (denoted cross program-A-E) are designed for each cross program given different levels of initial favorite allele frequencies, base population sizes and trait heritabilities. The process of gene pyramiding breeding for various schemes are simulated and compared based on the population hamming distance, average superior genotype frequencies and average phenotypic values. By simulation, the results show that the larger base population size and the higher the initial favorite allele frequency the higher the efficiency of gene pyramiding. Parents cross order is shown to be the most important factor in a cascading cross, but has no significant influence on the symmetric cross. The results also show that genotypic selection strategy is superior to phenotypic selection in accelerating gene pyramiding. Moreover, the method and corresponding software was used to compare different cross schemes and selection strategies.

Aesthetics of Karatedo as Security Guard Martial Art (경호무도로서 공수도의 미학)

  • Jeang, Il Hong
    • Convergence Security Journal
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    • v.13 no.2
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    • pp.67-73
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    • 2013
  • This research is to define the Aesthetics of Karatedo as Security Guard Martial Art by explore the aesthetics of Karatedo being invigorated as security guard martial art. The first one is beauty of space. The offense and defense of Karatedo as Security Guard Martial art are to fill in, to come out and to move from side to side. It help to have higher judgment. Secondly, it is beauty of time. It is subjective time felt by people training Karatedo. The third on is beauty of unity. We can see formal beauty of unity such as white dogi or black suit of security guard and dynamic beauty of unity such as quick and slow, strong and soft or movement of hand and foot. The forth one is beauty of symmetry. It can be shown strongly by triangle or moving of team kata and triangle between athletes and referee at Kumite competition. The fifth one is beauty of balance. It can by shown well by continual Karatedo kick motion, jumping kick motion at Kumite, jumping motion, quick turning, or moving such as standing on one foot at kata. The sixth one is beauty of harmony. The whith Dogi and blue or red guard at Kumite competition shows harmony of yin and yang and we can see also various harmony such as strong and soft, quick and slow, or high and low at Kata competition. The seventh one is beauty of curve. We can see beauty of straight line and curve by watching line of hand and foot from starting point to ending point. Specially, moving line of white dogi shows strongly beauty. The eighth one is beauty of rhythm. The rhythm is specified in Kumite kata competition rules. It is also shown by basic step, left and right step, various moving of foot, continual offense of hand or continual rhythm of offense and defense. The last one is bezuty of ethics. It is manner, duty as human, and moderation being important in Karatedo.

Synthesis and Crystal Structure of Ag4Br4 Nanoclusters in the Sodalite Cavities of Fully K+-Exchanged Zeolite A (LTA)

  • Lim, Woo-Taik;Choi, Sik-Young;Kim, Bok-Jo;Kim, Chang-Min;Lee, In-Su;Kim, Seok-Han;Heo, Nam-Ho
    • Bulletin of the Korean Chemical Society
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    • v.26 no.7
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    • pp.1090-1096
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    • 2005
  • $Ag_4Br_4$ nanoclusters have been synthesized in about 75% of the sodalite cavities of fully $K^+$-exchanged zeolite A (LTA). An additional KBr molecule is retained in each large cavity as part of a near square-planar $K_4Br^{3+}$ cation. A single crystal of $Ag_{12}$-A, prepared by the dynamic ion-exchange of $Na_{12}$-A with aqueous 0.05 M $AgNO_3$ and washed with $CH_3OH$, was placed in a stream of flowing 0.05 M KBr in $CH_3OH$ for two days. The crystal structure of the product ($K_9(K_4Br)Si_{12}Al_{12}O_{48}{\cdot}0.75Ag_4Br_4$, a = 12.186(1) $\AA$) was determined at 294 K by single-crystal X-ray diffraction in the space group Pm m. It was refined with all measured reflections to the final error index $R_1$ = 0.080 for the 99 reflections for which $F_o\;{\gt}\;4_{\sigma}\;(F_o)$. The thirteen $K^+$ ions per unit cell are found at three crystallographically distinct positions: eight $K^+$ ions in the large cavity fill the six-ring site, three $K^+$ ions fill the eight-rings, and two $K^+$ ions are opposite four-rings in the large cavity. One bromide ion per unit cell lies opposite a four-ring in the large cavity, held there by two eight-ring and two six-ring $K^+$ ions ($K_4Br^{3+}$). Three $Ag^+$ and three $Br^-$ions per unit cell are found on 3-fold axes in the sodalite unit, indicating the formation of nano-sized $Ag_4Br_4$ clusters (interpenetrating tetrahedra; symmetry $T_d$; diameter ca. 7.9 $\AA$) in 75% of the sodalite units. Each cluster (Ag-Br = 2.93(3) $\AA$) is held in place by the coordination of its four $Ag^+$ ions to the zeolite framework (each $Ag^+$ cation is 2.52(3) $\AA$ from three six-ring oxygens) and by the coordination of its four $Br^-$ ions to $K^+$ ions through six-rings (Br-K = 3.00(4) $\AA$).