650 research outputs found

    Parallel-vector unsymmetric Eigen-Solver on high performance computers

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    The popular QR algorithm for solving all eigenvalues of an unsymmetric matrix is reviewed. Among the basic components in the QR algorithm, it was concluded from this study, that the reduction of an unsymmetric matrix to a Hessenberg form (before applying the QR algorithm itself) can be done effectively by exploiting the vector speed and multiple processors offered by modern high-performance computers. Numerical examples of several test cases have indicated that the proposed parallel-vector algorithm for converting a given unsymmetric matrix to a Hessenberg form offers computational advantages over the existing algorithm. The time saving obtained by the proposed methods is increased as the problem size increased

    Seismic effects of the Caloris basin impact, Mercury

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    Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Earth, Atmospheric, and Planetary Sciences, 2011.Cataloged from PDF version of thesis. Page 46 blank.Includes bibliographical references (p. 41-45).Striking geological features on Mercury's surface have been linked to tectonic disruption associated with the Caloris impact and have the potential to provide information on the interior structure of Mercury. The unusual disrupted terrain located directly at the antipode of the 1500-km-diameter Caloris basin could have plausibly formed as a consequence of focused seismic waves generated by the massive impact event. In this paper, we revisit the antipodal seismic focusing effects of the Caloris impact by developing physically consistent structure models for Mercury and parameterized seismic source models for the Caloris impact. If the focused seismic body waves caused the disrupted terrain, then the amplitudes of the waves and the areal extent of surface disruptions could be used for estimating the seismic energy imparted by the impact. In this study, we show that effects of direct body waves are small relative to those of the focused guided waves. Two types of guided waves are generated by the Caloris impact. One is the conventional Rayleigh wave generated by the impact. The second is the mantle guided waves trapped between the core and the free surface. Mantle guided waves, not mentioned in previous studies, may have played an important role in the creation of the disrupted terrain. We find that the early core state has only moderate effects on the antipodal response to the Caloris impact. The fact that the zone of predicted disruption for both fluid and solid core cases is smaller than the observed region of chaotic terrain suggests either that the antipodal response to the Caloris impact may have been modulated by the shallow structure of Mercury, or that the energy imparted by the impact was larger than those used in this study.by Jiangning Lü.S.M

    Expression Robust 3D Face Landmarking Using Thresholded Surface Normals

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    3D face recognition is an increasing popular modality for biometric authentication, for example in the iPhoneX. Landmarking plays a significant role in region based face recognition algorithms. The accuracy and consistency of the landmarking will directly determine the effectiveness of feature extraction and hence the overall recognition performance. While surface normals have been shown to provide high performing features for face recognition, their use in landmarking has not been widely explored. To this end, a new 3D facial landmarking algorithm based on thresholded surface normal maps is proposed, which is applicable to widely used 3D face databases. The benefits of employing surface normals are demonstrated for both facial roll and yaw rotation calibration and nasal landmarks localization. Results on the Bosphorus, FRGC and BU-3DFE databases show that the detected landmarks possess high within-class consistency and accuracy under different expressions. For several key landmarks the performance achieved surpasses that of state-of-the-art techniques and is also training free and computationally efficient. The use of surface normals therefore provides a useful representation of the 3D surface and the proposed landmarking algorithm provides an effective approach to localising the key nasal landmarks.</p

    Using 3D Representations of the Nasal Region for Improved Landmarking and Expression Robust Recognition

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    This paper investigates the performance of different representations of 3D human nasal region for expression robust recognition. By performing evaluations on the depth and surface normal components of the facial surface, the nasal region is shown to be relatively consistent over various expressions, providing motivation for using the nasal region as a biometric. A new efficient landmarking algorithm that thresholds the local surface normal components is proposed and demonstrated to produce an improved recognition performance for nasal curves from both the depth and surface normal components. The use of the Shape Index for feature extraction is also investigated and shown to produce a good recognition performance

    A Theoretical Framework on the Peculiarity of Doing Business in China—An Extensive Review on HBSP China Business Cases

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    After reviewing 397 Asia-Pacific Region business cases studies, published by Harvard Business School Publishing (HBSP) from 2005 to 2013, and by comparing the 166 China cases and the 231 non-China cases, this paper proposes a theoretical framework, namely, the peculiarity of doing business in China. Despite their great contribution in fulfilling the urgent need for China case studies in business education, and revealing the pivotal role of business and government relationship as the vital challenge of doing business in China, however, the mechanism of how this relationship has been leveraged as a peculiar and decisive competitive advantage for indigenous business (inferior resources) to outperform those FDIs (superior resources) in China, has remained as an unanswered, or not even been acknowledged question. The combination of the three identified cognitive weaknesses has been the prevailed barrier, hindering Western scholars to acknowledge the peculiarity of doing business in China and to understand China politically-dominated and culturally-oriented business environment, and consequently, leading to the stereotyped application of Western framework of management in perceiving, observing and interpreting pseudo-socialist business environment and behaviors in China, in which, business is by nature NOT market-oriented like in those Western countries. The fact being ignored is that, the combination of government and Guanxi Network constitutes the backbone of business environment, in which, what you can do depends on who you know, is the core determinant of organizational and individual behaviors, supporting and protecting the peculiarly structured chain-of-beneficiaries in China. Lastly, given the lag between business education and practice, the proposed framework may timely serve to enrich the paradigm of international business management

    Lycorine reduces mortality of human enterovirus 71-infected mice by inhibiting virus replication

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    Human enterovirus 71 (EV71) infection causes hand, foot and mouth disease in children under 6 years old and this infection occasionally induces severe neurological complications. No vaccines or drugs are clinical available to control EV71 epidemics. In present study, we show that treatment with lycorine reduced the viral cytopathic effect (CPE) on rhabdomyosarcoma (RD) cells by inhibiting virus replication. Analysis of this inhibitory effect of lycorine on viral proteins synthesis suggests that lycorine blocks the elongation of the viral polyprotein during translation. Lycorine treatment of mice challenged with a lethal dose of EV71 resulted in reduction of mortality, clinical scores and pathological changes in the muscles of mice, which were achieved through inhibition of viral replication. When mice were infected with a moderate dose of EV71, lycorine treatment was able to protect them from paralysis. Lycorine may be a potential drug candidate for the clinical treatment of EV71-infected patients
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