26,283 research outputs found

    Left-Right Asymmetry of Weak Interaction Mass of Polarized Fermions in Flight

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    The left-right polarization-dependent asymmetry of the weak interaction mass is investigated. Based on the Standard Model, the calculation shows that the weak interaction mass of left-handed polarized fermions is always greater than that of right-handed polarized fermions in flight with the same velocity in any inertial frame. The asymmetry of the weak interaction mass might be very important to the investigation of neutrino mass and would have an important significance for understanding the parity nonconservation in weak interactions.Comment: 8 pages, 2 figures, corrected calculatio

    Backaction of a charge detector on a double quantum dot

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    We develop a master equation approach to study the backaction of quantum point contact (QPC) on a double quantum dot (DQD) at zero bias voltage. We reveal why electrons can pass through the zero-bias DQD only when the bias voltage across the QPC exceeds a threshold value determined by the eigenstate energy difference of the DQD. This derived excitation condition agrees well with experiments on QPC-induced inelastic electron tunneling through a DQD [S. Gustavsson et al., Phys. Rev. Lett. 99, 206804(2007)]. Moreover, we propose a new scheme to generate a pure spin current by the QPC in the absence of a charge current.Comment: 6 pages, 4 figure

    Learning Points and Routes to Recommend Trajectories

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    The problem of recommending tours to travellers is an important and broadly studied area. Suggested solutions include various approaches of points-of-interest (POI) recommendation and route planning. We consider the task of recommending a sequence of POIs, that simultaneously uses information about POIs and routes. Our approach unifies the treatment of various sources of information by representing them as features in machine learning algorithms, enabling us to learn from past behaviour. Information about POIs are used to learn a POI ranking model that accounts for the start and end points of tours. Data about previous trajectories are used for learning transition patterns between POIs that enable us to recommend probable routes. In addition, a probabilistic model is proposed to combine the results of POI ranking and the POI to POI transitions. We propose a new F1_1 score on pairs of POIs that capture the order of visits. Empirical results show that our approach improves on recent methods, and demonstrate that combining points and routes enables better trajectory recommendations

    Impact of Topology on Service Availability in a Smart Grid Advanced Metering Infrastructure

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    over the last decade, Wireless Sensor Networks (WSNs) have brought radical changes to the means and forms of communication for monitoring and control of a large number of applications including Smart Grid (SG). Traditional energy networks have been modernized to Smart Grids to boost the energy industry in the context of efficient and effective power management, performance, real-time control and information flow using two-way communication between utility provides and end-users. However, integrating two-way communication in smart grid comes at the cost of cyber security vulnerabilities and challenges. In the context of SG, node capture is a severe security threat due to the fact that a compromised node can significantly impact the operations and security of the SG network. In this paper, node compromise attack is explored on Advance Metering Infrastructure (AMI) with smart meters for Neighbor Area Networks (NANs) in star and mesh network topologies. Simulation of node compromise/failure for a SG network, using ZigBee nodes in simulation indicates that a partial mesh topology is more resilient to node capture attacks as compared to star topology. A larger number of nodes are reachable from the control center of the SG in a partial mesh topology compared to that in a star topology
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