3,237 research outputs found

    Stability and asymptotic stability in the energy space of the sum of N solitons for subcritical gKdV equations

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    We prove in this paper the stability and asymptotic stability in H^1 of a decoupled sum of N solitons for the subcritical generalized KdV equations ut+(uxx+up)x=0u_t+(u_{xx}+u^p)_x=0 (1<p<5). The proof of the stability result is based on energy arguments and monotonicity of local L^2 norm. Note that the result is new even for p=2 (the KdV equation). The asymptotic stability result then follows directly from a rigidity theorem in [15]

    Static and Dynamic Structural Response of an Aircraft Wing with Damage Using Equivalent Plate Analysis

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    A process to generate an equivalent plate based on an optimization approach to predict the static and dynamic response of flight vehicle wing structures is proposed. Geometric-scale and frequency-scale factors are defined to construct an equivalent plate with any desired scale to use in simulation and wind tunnel experiments. It is shown that the stiffness and the displacements are scaled linearly with the geometric-scale factor, whereas the load is scaled as the square of the geometric-scale factor. The scaled stiffness of the reference flight vehicle is matched first to construct the equivalent plate. Then the frequency-scale factor is defined to scale the flight vehicle frequencies. The scaled flight vehicle frequencies are matched by placing arbitrary point masses along the equivalent plate geometry. Two simple stiffened-plate examples, one with damage and another without damage, were used to demonstrate the accuracy of the optimization procedure proposed. Geometric-scale factors ranging from 0.2 to 1.0 were used in the analyses. In both examples, the static and dynamic response of the reference stiffened-panel solution is matched accurately. The scaled equivalent plate predicted the first five frequencies of the stiffened panel very accurately. Finally, the proposed equivalent plate procedure was demonstrated in a more realistic typical aircraft wing structure. Two scale equivalent plate models were generated using the geometric-scale factors 1.0 and 0.2. Both equivalent plate models predicted the static response of the wing structure accurately. The equivalent plate models reproduced the first five frequencies of the wing structure accurately

    The Application of RFID in Emergency Medicine

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    Recently natural disasters and man-made calamities happened very frequently in Taiwan, some of which caused hundreds of inhabitants died and injured. The most important thing that makes the emergency medical treatment system work effectively during these catastrophes is dependent on the accuracy and immediacy of the information among ambulances, hospitals, fire bureaus, public health bureaus or offices, and emergency executive centers. With this information, the medical system can arrange the resources efficiently. Radio frequency identification (RFID) is a kind of wireless technology that it uses radio frequency (RF) to identify target objects. The characteristics of RFID are its identification and orientation. Through tracing electronic signals, RFID is able to identify, orientate and trace patients or medical materials directly and continuously. Thus, RFID can help managers of medical institutions to promote emergency medical treatment quality, reduce medical mistakes effectively, and increase efficiency and effectiveness in hospitals. A series of emergency medical delivery applications that use 915MHz RFID rings is developed in this paper. Through the help of RFID, the paper integrates the information of the whole emergency medical supply chain, and establishes a new model of emergency medical activities to solve the problems of information blocking among different medical rescue units. By solving these problems, the new model can enhance the rescue quality, reduce the damage of the disaster and strengthen the patient-oriented emergency care system

    Distributed active control for tension structures

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    Thesis (M.Eng.)--Massachusetts Institute of Technology, Dept. of Civil and Environmental Engineering, 2000.Includes bibliographical references (leaf 37).by Frank J. Tsai.M.Eng

    Symplectic integrators for classical spin systems

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    We suggest a numerical integration procedure for solving the equations of motion of certain classical spin systems which preserves the underlying symplectic structure of the phase space. Such symplectic integrators have been successfully utilized for other Hamiltonian systems, e. g. for molecular dynamics or non-linear wave equations. Our procedure rests on a decomposition of the spin Hamiltonian into a sum of two completely integrable Hamiltonians and on the corresponding Lie-Trotter decomposition of the time evolution operator. In order to make this method widely applicable we provide a large class of integrable spin systems whose time evolution consists of a sequence of rotations about fixed axes. We test the proposed symplectic integrator for small spin systems, including the model of a recently synthesized magnetic molecule, and compare the results for variants of different order

    An interactive 3-D application for pain management: Results from a pilot study in spinal cord injury rehabilitation

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    This is the post-print version of the Article. The official published version can be accessed from the link below - Copyright @ 2012 ElevierResearch on pain following spinal cord injury (SCI) has revealed that patients not only experience several types of pain that could prove to be challenging to address, but also that each individual can interpret such pain in different subjective ways. In this paper we introduce a 3-D system for facilitating the efficient management of pain, and thus, supporting clinicians in overcoming the aforementioned challenges. This system was evaluated by a cohort of 15 SCI patients in a pilot study that took place between July and October 2010. Participants reported their experiences of using the 3-D system in an adapted version of the System Usability Scale (SUS) questionnaire. Statistically significant results were obtained with regards to the usability and efficiency of the 3-D system, with the majority of the patients finding it particularly useful to report their pain. Our findings suggest that the 3-D system can be an efficient tool in the efforts to better manage the pain experience of SCI patients
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