1,374 research outputs found
Efficient Authenticated Encryption Schemes with Public Verifiability
An authenticated encryption scheme allows messages to be encrypted and
authenticated simultaneously. In 2003, Ma and Chen proposed such a scheme with
public verifiability. That is, in their scheme the receiver can efficiently
prove to a third party that a message is indeed originated from a specific
sender. In this paper, we first identify two security weaknesses in the Ma-Chen
authenticated encryption scheme. Then, based on the Schnorr signature, we
proposed an efficient and secure improved scheme such that all the desired
security requirements are satisfied.Comment: Early version appears in the Proc. of The 60th IEEE Vehicular
Technology Conference (VTC 2004-Fall) - Wireless Technologies for Global
Security. IEEE, 200
Information filtering based on corrected redundancy-eliminating mass diffusion
Methods used in information filtering and recommendation often rely on quantifying the similarity between objects or users. The used similarity metrics often suffer from similarity redundancies arising from correlations between objects’ attributes. Based on an unweighted undirected object-user bipartite network, we propose a Corrected Redundancy-Eliminating similarity index (CRE) which is based on a spreading process on the network. Extensive experiments on three benchmark data sets— Movilens, Netflix and Amazon—show that when used in recommendation, the CRE yields significant improvements in terms of recommendation accuracy and diversity. A detailed analysis is presented to unveil the origins of the observed differences between the CRE and mainstream similarity indices
The contribution of ultracompact dark matter minihalos to the isotropic radio background
The ultracompact minihalos could be formed during the earlier epoch of the
universe. The dark matter annihilation within them is very strong due to the
steep density profile, . The high energy electrons and
positrons from the dark matter annihilation can inverse Compton scatter (ICS)
with the background photons, such as CMB photons, to acquire higher energy. On
the other hand, the synchrotron radiation can also be produced when they meet
the magnetic field. In this paper, we study the signals from the UCMHs due to
the dark matter annihilation for the radio, X-ray and -ray band. We
found that for the radio emission the UCMHs can provide one kind of source for
the radio excess observed by ARCADE 2.
But the X-ray signals due to the ICS effect or the -ray signals
mainly due to the prompt emission from dark matter would exceed the present
observations, such as Fermi, COMPTEL and CHANDRA. We found that the strongest
limits on the fraction of UCMHs come from the X-ray observations and the
constraints from the radio data are the weakest.Comment: 6 pages, 8 figures, Comments Welcome! Some Refs. are added, some
presentation have been corrected. The conclusions remain unchanged. One
important reference has been corrected. Some presentations are changed and
added according to the referee's comments. Accepted for publication in PR
An Efficient Wireless Recharging Mechanism for Achieving Perpetual Lifetime of Wireless Sensor Networks
[[abstract]]Energy recharging has received much attention in recent years. Several recharging mechanisms were proposed for achieving perpetual lifetime of a given Wireless Sensor Network (WSN). However, most of them require a mobile recharger to visit each sensor and then perform the recharging task, which increases the length of the recharging path. Another common weakness of these works is the requirement for the mobile recharger to stop at the location of each sensor. As a result, it is impossible for recharger to move with a constant speed, leading to inefficient movement. To improve the recharging efficiency, this paper takes “recharging while moving” into consideration when constructing the recharging path. We propose a Recharging Path Construction (RPC) mechanism, which enables the mobile recharger to recharge all sensors using a constant speed, aiming to minimize the length of recharging path and improve the recharging efficiency while achieving the requirement of perpetual network lifetime of a given WSN. Performance studies reveal that the proposed RPC outperforms existing proposals in terms of path length and energy utilization index, as well as visiting cycle.[[notice]]補正完
Boron neutron capture therapy induces cell cycle arrest and cell apoptosis of glioma stem/progenitor cells in vitro
BACKGROUND: Glioma stem cells in the quiescent state are resistant to clinical radiation therapy. An almost inevitable glioma recurrence is due to the persistence of these cells. The high linear energy transfer associated with boron neutron capture therapy (BNCT) could kill quiescent and proliferative cells. METHODS: The present study aimed to evaluate the effects of BNCT on glioma stem/progenitor cells in vitro. The damage induced by BNCT was assessed using cell cycle progression, apoptotic cell ratio and apoptosis-associated proteins expression. RESULTS: The surviving fraction and cell viability of glioma stem/progenitor cells were decreased compared with differentiated glioma cells using the same boronophenylalanine pretreatment and the same dose of neutron flux. BNCT induced cell cycle arrest in the G2/M phase and cell apoptosis via the mitochondrial pathway, with changes in the expression of associated proteins. CONCLUSIONS: Glioma stem/progenitor cells, which are resistant to current clinical radiotherapy, could be effectively killed by BNCT in vitro via cell cycle arrest and apoptosis using a prolonged neutron irradiation, although radiosensitivity of glioma stem/progenitor cells was decreased compared with differentiated glioma cells when using the same dose of thermal neutron exposure and boronophenylalanine pretreatment. Thus, BNCT could offer an appreciable therapeutic advantage to prevent tumor recurrence, and may become a promising treatment in recurrent glioma
Preparation of Cu2ZnSnS/Se4 Thin Films from Oxide Precursors and its Prospect for Other Cu2MSnS4 Thin Films
In this chapter, the preparation of Cu2ZnSnSe4 (CZTSe) and Cu2ZnSnS4 (CZTS) thin films from oxide precursors was described. Such an oxides‐based route is a low cost, facile way for the kesteries thin films. The rationality of applying oxides method into CZTSe and CZTS thin films was also clarified, including the reactive thermodynamics and annealing process. Finally, this oxide‐based approach is also expected for the preparation of the other Cu2MSnS4 (M= Co2+, Fe2+, Ni2+, Mn2+) thin films
On Sum Rate Maximization Study for Cellular-Connected UAV Swarm Communications
AbstractThe integration of cellular networks and unmanned aerial vehicle (UAV) swarm communications is expected to be a promising technology to provide ubiquitous network connectivity for various UAV assisted Internet of Things (IoT) applications. To support these IoT applications with stringent requirement of rate performance, this paper explores the maximum sum rate performance for the cellular-connected UAV swarm communications. The sum rate maximization can be formulated as a nonlinear and nonconvex optimization problem with the constraints of transmit power of UAVs, elevation angle, azimuth angle and height of antenna array equipped at base station (BS). According to the Karush–Kuhn–Tucker (KKT) optimality conditions and the standard interference function, we propose an iterative algorithm to solve the problem, wherein the problem is transformed into a concave optimization problem by utilizing the rate approximation and logarithmic transformations. The iterative algorithm is proved to converge to a global solution for the approximated concave optimization problem. Finally, simulation results are provided to indicate the effect of some important system parameters on the sum rate performance in the system.Abstract
The integration of cellular networks and unmanned aerial vehicle (UAV) swarm communications is expected to be a promising technology to provide ubiquitous network connectivity for various UAV assisted Internet of Things (IoT) applications. To support these IoT applications with stringent requirement of rate performance, this paper explores the maximum sum rate performance for the cellular-connected UAV swarm communications. The sum rate maximization can be formulated as a nonlinear and nonconvex optimization problem with the constraints of transmit power of UAVs, elevation angle, azimuth angle and height of antenna array equipped at base station (BS). According to the Karush–Kuhn–Tucker (KKT) optimality conditions and the standard interference function, we propose an iterative algorithm to solve the problem, wherein the problem is transformed into a concave optimization problem by utilizing the rate approximation and logarithmic transformations. The iterative algorithm is proved to converge to a global solution for the approximated concave optimization problem. Finally, simulation results are provided to indicate the effect of some important system parameters on the sum rate performance in the system
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