• Title/Summary/Keyword: Time Reversal

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Interocular interactions evoked by asynchronous checkerboard pattern reversals to each eye

  • Park, Hyoung-Dong;Lee, Kyoung-Min
    • Proceedings of the Korean Society for Cognitive Science Conference
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    • 2010.05a
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    • pp.55-59
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    • 2010
  • To examine iterocular interactions in normal subjects, we recorded EEG activity from channel O1 and O2 on 14 healthy subjects while checkerboard pattern reversals were presented to each eye with different interstimulus intervals (ISIs) ranging from 0 to 218 ms. When pattern reversals were presented asynchronously to each eye, P-1 activity evoked by each reversal was significantly suppressed compared to the activation evoked by synchronous reversals. Furthermore, when there was time delay between pattern reversals to each eye, theta (4-10 Hz) band power was also significantly decreased, whereas beta (10-30 Hz) band power was relatively preserved. Our results suggest that neural activity evoked by sustained but not yet reversed checkerboard from one eye might inhibit upcoming neural response evoked by reversed checkerboard from the other eye. Decreased P-1 activity might reflect such inhibitory interaction between two eyes. Also, decreased theta and preserved beta band power might reflect engagement of different neural circuit for binocular / monocular vision.

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Analytical model for the throughput capacity of single carousel (단일 캐러젤의 처리능력에 관한 분석적 모형)

  • 임석철
    • Korean Management Science Review
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    • v.11 no.1
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    • pp.39-50
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    • 1994
  • Carousel systems can be classified into unidirectional and bidirectional carousel, depending on the hardware structure. Bidirectional carousels again can be classified into reversible and irreversible carousel, depending on whether the reversal of direction is allowed or not during the process of an order. In this study, single carousel served by one operator is considered. Analytical models for the rotation distance to process an order of size are developed for unidirectional and irreversible bidirectional cases. For reversible bidirectional and Nearest Neighbor Heuristic cases, simulation results of the average rotation distance are presented. Since the throughput capacity of carousel systems also depends upon the picking time of the operator; order size; and the rotation speed of carousel, the model considers the above three factors to express the throughput capacity of single carousel systems.

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Source finding in reflection and refraction environment using based on ray tracing method TRM (음선 추적법 기반 TRM을 이용한 반사 및 굴절 환경 속의 소음원 탐색에 대한 연구)

  • Moon, Sang Il;Lee, Jae Hyung;Choi, Jong Soo
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • 2014.10a
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    • pp.727-732
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    • 2014
  • The goal is to find the position of the sound source with the TRM at reflections and refractions environment. The Fermat's principle applied to the ray tracing method are expected to follow the acoustic path in order to obtain acoustic distance and transmittance to. Utilizing them in the TRM was confirmed rear reflectance affect on estimated position, resolution and side lobe. And the TRM performance were superior to one of the beam forming techniques.

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Epitaxial Growth of Bi2Se3 on a Metal Substrate

  • Jeon, Jeong-Heum;Jang, Won-Jun;Yun, Jong-Geon;Gang, Se-Jong
    • Proceedings of the Korean Vacuum Society Conference
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    • 2011.02a
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    • pp.306-306
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    • 2011
  • Three dimensional(3D) topological insulators(TIs) of Bi binary alloys are characterized by a bulk energy gap with strong spin-orbit coupling and metallic surface states protected by time-reversal symmetry. It was reported that film forms of such materials were advantageous over bulk forms due to less defect density and better crystallinity. So far, the films have been prepared on several substrates including semiconductors and graphene. But, there were no studies on metal substrates. For electronic transport experiments and device applications, it is necessary to know epitaxial relation between TIs and metal electrodes. In this study, Atomically flat films of Bi2Se3 were grown on a Au(111) metal substrate by in-situ molecular beam epitaxy. Using home-built scanning tunneling microscope, we observed hexagonal atomic structures which corresponded to the outmost selenium atomic layer of Bi2Se3. Triangular-shaped defects known as Selenium vacancy were also found.

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Characteristic Studies on the Stone Cultural Heritage by Shape Reversal Engineerings (석조문화재의 형상역공학적 특성연구)

  • Shon, Ho-Woong;Lee, Kang-Won
    • Proceedings of the Korean Society of Surveying, Geodesy, Photogrammetry, and Cartography Conference
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    • 2009.04a
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    • pp.59-63
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    • 2009
  • Structures show the phenomena of deformation and lowering of function with time-lapse by artificial environments and changes of geotechnical conditions or accumulation of initial deformation elements. This study aims the structural assessment of cultural heritage. Non-destructive evaluation techniques were applied to protect it from survey: 3D precise laser scanning surveying system was applied to measure the exact size, displacement and declining angles.

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Measurements of Local Coercivity Distribution in Ferromagnetic Films Using Magneto-Optical Microscope Magnetometer (MOMM)

  • Choe, Sug-Bong;Shin, Sung-Chul
    • Journal of Magnetics
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    • v.5 no.3
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    • pp.81-84
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    • 2000
  • A magneto-optical microscope magnetometer (MOMM) has been developed to simultaneously measure 2-dimensional array hysteresis loops of each local area of $320\times320-nm^2$ spots on ferromagnetic films, in addition to grabbing time-resolved domain evolution patterns. Using the system, spatial distribution of local coercivity can be quantitatively generated and then, compared directly with domain patterns grabbed at precisely the same position of a sample. It is clearly demonstrated that local coercivity distribution governs domain reversal behavior via a thermally activated relaxation process.

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A Study on Dok-Rak-Dang and Hyang-Dan, Upper Class Houses of Chosun Dynasty, with The Perspective of Deconstructionist Art Theory (독락당(獨樂堂) 일곽(一郭)과 향단(香壇)의 해체예술론(解體藝術論)적 고찰 - Christopher Norris의 해체예술의 세 특성을 중심으로 -)

  • Kweon, Tae-Ill
    • Journal of architectural history
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    • v.15 no.4
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    • pp.87-105
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    • 2006
  • Dok-Rak-Dang and Hyang-Dan, upper class houses of Chosun Dynasty on the early and mid 16th century, are generally known as specific style houses among traditional residences in Korea. Architectural singularities of these two residences are summarized as double facades, uncertain circulation, self-secluding construction, dilemmatic structure, and rotative circulation that are far from architectonic principle of that time. Characters of Deconstructionist Art, deconstruction of binary oppositions, double session, displacement without reversal, and paradox, are very similar to those of two residences both as a material phenomenon and as a metaphysical idea. Thus, this paper attempt to analyze architectural singularities of Dok-Rak-Dang and Hyang-Dan with the perspective of Deconstructionist Art Theory.

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Two-Dimensional Phase Retrieval Using Window Functions (윈도우 함수를 이용한 2차원 신호의 위상복원)

  • Kim, Woo-Shik
    • Journal of the Korean Institute of Telematics and Electronics S
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    • v.35S no.10
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    • pp.126-134
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    • 1998
  • In this paper, we consider the problem of reconstructing a two-dimensional signal from its Fourier intensity and the Fourier intensities of two windowed signals: one by a window w(m,n) and the other by its complementary window [1-w(m,n)]. We develop several conditions under which a signal can be uniquely specified to within several trivial ambiguities such as sign, translation,and time-reversal from the given conditions. We present two possible reconstruction algorithms derived from the Gerchberg-Saxton algorithm.

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Low-cost crowbar system and protection scheme in capacitor bank module (커패시터 뱅크 모듈 구성에 있어서 경제적인 크로바 시스템과 보호회로)

  • Rim, Geun-Hie;Cho, Chu-Hyun;Lee, Hong-Sik;Pavlov, E.P.
    • Proceedings of the KIEE Conference
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    • 2000.07c
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    • pp.2089-2091
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    • 2000
  • Pulsed power systems consist of a capacitor bank, an isolated high-voltage charging power-supply, high-current bus-work for charging and discharging and a control system. In such pulsed power systems, the operating-lifetime of the capacitors is closely dependent on the voltage reversal. Hence, most capacitor-discharging systems includes crowbar circuits. The crowbar circuit prevents the capacitor recharging with reverse voltage. Usually it consists of crowbar resistors and high pulse-current diode-stacks connected in series. The requirements for the diode-stacks are fast-recovery time and high-voltage and large-current ratings, which results in the high cost of the pulsed-power system. This paper presents a protection scheme of a charging and discharging system of a 500kJ capacitor bank using a low-cost crowbar circuit and safety-fuses.

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A mortar mix proportion design algorithm based on artificial neural networks

  • Ji, Tao;Lin, Xu Jian
    • Computers and Concrete
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    • v.3 no.5
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    • pp.357-373
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    • 2006
  • The concepts of four parameters of nominal water-cement ratio, equivalent water-cement ratio, average paste thickness, fly ash-binder ratio were introduced. It was verified that the four parameters and the mix proportion of mortar can be transformed each other. The behaviors (strength, workability, et al.) of mortar primarily determined by the mix proportion of mortar now depend on the four parameters. The prediction models of strength and workability of mortar were built based on artificial neural networks (ANNs). The calculation models of average paste thickness and equivalent water-cement ratio of mortar can be obtained by the reversal deduction of the two prediction models, respectively. A mortar mix proportion design algorithm was proposed. The proposed mortar mix proportion design algorithm is expected to reduce the number of trial and error, save cost, laborers and time.