12,331 research outputs found
Hamiltonian and measuring time for analog quantum search
We derive in this study a Hamiltonian to solve with certainty the analog
quantum search problem analogue to the Grover algorithm. The general form of
the initial state is considered. Since the evaluation of the measuring time for
finding the marked state by probability of unity is crucially important in the
problem, especially when the Bohr frequency is high, we then give the exact
formula as a function of all given parameters for the measuring time.Comment: 5 page
Biomechanical mechanisms underlying exosuit-induced improvements in walking economy after stroke
Stroke-induced hemiparetic gait is characteristically asymmetric and metabolically expensive. Weakness and impaired control of the paretic ankle contribute to reduced forward propulsion and ground clearance—walking subtasks critical for safe and efficient locomotion. Targeted gait interventions that improve paretic ankle function after stroke are therefore warranted. We have developed textile-based, soft wearable robots that transmit mechanical power generated by off-board or body-worn actuators to the paretic ankle using Bowden cables (soft exosuits) and have demonstrated the exosuits can overcome deficits in paretic limb forward propulsion and ground clearance, ultimately reducing the metabolic cost of hemiparetic walking. This study elucidates the biomechanical mechanisms underlying exosuit-induced reductions in metabolic power. We evaluated the relationships between exosuit-induced changes in the body center of mass (COM) power generated by each limb, individual joint powers, and metabolic power. Compared to walking with an exosuit unpowered, exosuit assistance produced more symmetrical COM power generation during the critical period of the step-to-step transition (22.4±6.4% more symmetric). Changes in individual limb COM power were related to changes in paretic (R2= 0.83, P= 0.004) and nonparetic (R2= 0.73, P= 0.014) ankle power. Interestingly, despite the exosuit providing direct assistance to only the paretic limb, changes in metabolic power were related to changes in nonparetic limb COM power (R2= 0.80, P= 0.007), not paretic limb COM power (P> 0.05). These findings provide a fundamental understanding of how individuals poststroke interact with an exosuit to reduce the metabolic cost of hemiparetic walking.Accepted manuscript2019-03-0
Exosuit-induced improvements in walking after stroke: comprehensive analysis on gait energetics and biomechanics
Outstanding Poster Presentation Finalis
A V-Diagram for the Design of Integrated Health Management for Unmanned Aerial Systems
Designing Integrated Vehicle Health Management (IVHM) for Unmanned Aerial Systems (UAS) is inherently complex. UAS are a system of systems (SoS) and IVHM is a product-service, thus the designer has to take into account many factors, such as: the design of the other systems of the UAS (e.g. engines, structure, communications), the split of functions between elements of the UAS, the intended operation/mission of the UAS, the cost verses benefit of monitoring a system/component/part, different techniques for monitoring the health of the UAS, optimizing the health of the fleet and not just the individual UAS, amongst others. The design of IVHM cannot sit alongside, or after, the design of UAS, but itself be integrated into the overall design to maximize IVHM’s potential.
Many different methods exist to help design complex products and manage the process. One method used is the V-diagram which is based on three concepts: decomposition & definition; integration & testing; and verification & validation. This paper adapts the V-diagram so that it can be used for designing IVHM for UAS. The adapted v-diagram splits into different tracks for the different system elements of the UAS and responses to health states (decomposition and definition). These tracks are then combined into an overall IVHM provision for the UAS (integration and testing), which can be verified and validated. The stages of the adapted V-diagram can easily be aligned with the stages of the V-diagram being used to design the UAS bringing the design of the IVHM in step with the overall design process. The adapted V-diagram also allows the design IVHM for a UAS to be broken down in to smaller tasks which can be assigned to people/teams with the relevant competencies. The adapted V-diagram could also be used to design IVHM for other SoS and other vehicles or products
Subthreshold characteristics of pentacene field-effect transistors influenced by grain boundaries.
Grain boundaries in polycrystalline pentacene films significantly affect the electrical characteristics of pentacene field-effect transistors (FETs). Upon reversal of the gate voltage sweep direction, pentacene FETs exhibited hysteretic behaviours in the subthreshold region, which was more pronounced for the FET having smaller pentacene grains. No shift in the flat-band voltage of the metal-insulator-semiconductor capacitor elucidates that the observed hysteresis was mainly caused by the influence of localized trap states existing at pentacene grain boundaries. From the results of continuous on/off switching operation of the pentacene FETs, hole depletion during the off period is found to be limited by pentacene grain boundaries. It is suggested that the polycrystalline nature of a pentacene film plays an important role on the dynamic characteristics of pentacene FETs
PAMELA's cosmic positron from decaying LSP in SO(10) SUSY GUT
We propose two viable scenarios explaining the recent observations on cosmic
positron excess. In both scenarios, the present relic density in the Universe
is assumed to be still supported by thermally produced WIMP or LSP (\chi). One
of the scenarios is based on two dark matter (DM) components (\chi,X) scenario,
and the other is on SO(10) SUSY GUT. In the two DM components scenario,
extremely small amount of non-thermally produced meta-stable DM component
[O(10^{-10}) < n_X /n_\chi] explains the cosmic positron excess. In the SO(10)
model, extremely small R-parity violation for LSP decay to e^\pm is naturally
achieved with a non-zero VEV of the superpartner of one right-handed neutrino
(\tilde{\nu}^c) and a global symmetry.Comment: 6 pages, Talks presented in PASCOS, SUSY, and COSMO/CosPA in 201
Mean field baryon magnetic moments and sumrules
New developments have spurred interest in magnetic moments (-s) of
baryons. The measurement of some of the decuplet -s and the findings of
new sumrules from various methods are partly responsible for this renewed
interest. Our model, inspired by large colour approximation, is a relativistic
self consistent mean field description with a modified Richardson potential and
is used to describe the -s and masses of all baryons with up (u), down (d)
and strange (s) quarks. We have also checked the validity of the Franklin
sumrule (referred to as CGSR in the literature) and sumrules of Luty,
March-Russell and White. We found that our result for sumrules matches better
with experiment than the non-relativistic quark model prediction. We have also
seen that quark magnetic moments depend on the baryon in which they belong
while the naive quark model expects them to be constant.Comment: 7 pages, no figure, uses epl.cl
Primal-Dual 2-Approximation Algorithm for the Monotonic Multiple Depot Heterogeneous Traveling Salesman Problem
We study a Multiple Depot Heterogeneous Traveling Salesman Problem (MDHTSP) where the cost of the traveling between any two targets depends on the type of the vehicle. The travel costs are assumed to be symmetric, satisfy the triangle inequality, and are monotonic, i.e., the travel costs between any two targets monotonically increases with the index of the vehicles. Exploiting the monotonic structure of the travel costs, we present a 2-approximation algorithm based on the primal-dual method
Unusual Higgs or Supersymmetry from Natural Electroweak Symmetry Breaking
This review provides an elementary discussion of electroweak symmetry
breaking in the minimal and the next-to-minimal supersymmetric models with the
focus on the fine-tuning problem -- the tension between natural electroweak
symmetry breaking and the direct search limit on the Higgs boson mass. Two
generic solutions of the fine-tuning problem are discussed in detail: models
with unusual Higgs decays; and models with unusual pattern of soft
supersymmetry breaking parameters.Comment: 23 pages, 6 figures; invited review by MPL
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