A Secure Mutual Authentication Scheme of Blockchain-Based in WBANs

Wireless Body Area Networks(WBANs)refer to small sensor network that consists of sensor devices mounted on the surface of the body or implanted in the body,as such networks are employed to harvest physiological data of the human body or to act as an assistant regulator of several specific physiological indicators of the human body.The sensor devices transmit the harvested human physiological data to the local node via a public channel.Before transmitting data,the sensor device and the local node should perform mutual authentication and key agreement.It is proposed in this paper a secure mutual authentication scheme of blockchain-based in WBANs.To analyze the security of this scheme,formal security analysis,and informal security analysis are used,then the computation and communication costs are compared with those of the relevant schemes.Relevant experimental results reveal that the proposed scheme exhibit more effective control over energy consumption and promising.

并行应用于3D地震偏移的Butterworth和Chebyshev倾角滤波器

倾角滤波器是一个精确的频率-空间域偏移所必需的,因此,可靠和高效的滤波器设计和应用在理论上及实际上都是同等重要的。频率-空间域倾角滤波器通过使用Butterworth和Chebyshev运算法则来实现。把滤波器转换函数的乘积项转换为计算求和,一个串接(一系列)的Butterworth和Chebyshev倾角滤波器能够并行以提高效率。对于一个给定阶次的滤波器的,Butterworth和Chebyshev滤波器的成本是相同的。然而,Chebyshev滤波器具有一个比相同阶次的Butterworth滤波器狭窄的过渡带,但是在一些以波数-依赖的振幅波动为代价下,使它对于相位补偿比Butterworth滤波器有更高的效率。对于耗散能量的消除和对于分割误差的相位补偿,两种实现的方法已经被3D单向的频率-空间深度域偏移合并在了一起;一个单一的滤波器完成了两个目标。

Experiments with Two New Boosting Algorithms

Boosting is an effective classifier combination method, which can improve classification performance of an unstable learning algorithm. But it dose not make much more improvement of a stable learning algorithm. In this paper, multiple TAN classifiers are combined by a combination method called Boosting-MultiTAN that is compared with the Boosting-BAN classifier which is boosting based on BAN combination. We describe experiments that carried out to assess how well the two algorithms perform on real learning problems. Fi- nally, experimental results show that the Boosting-BAN has higher classification accuracy on most data sets, but Boosting-MultiTAN has good effect on others. These results argue that boosting algorithm deserve more attention in machine learning and data mining communities.

Microstructure, mechanical properties and deformation mechanisms of an as-cast Mg–Zn–Y–Nd–Zr alloy for stent applications

A new Mg-2Zn-0.2Y -0.5N d-0.4Zr (wt%) alloy designed specially for stent applications has been developed. The as-cast alloy is featured with equiaxed grains with a mean size of about 40 μm and a small am ount of second phase (T phase) distributed discontinuously either at the grain boundaries or inside the grains. This alloy exhibits a tensile elongation of up to 35%, which is much larger than that of most reported other as-cast Mg alloys. The tensile deform ation mechanisms have also been investigated. The results show that, besides basal slip,{10-12} extension twining and non-basal pyramidal slips can also be observed at initial stage and later stage during tensile deform ation, respectively, which are responsible for the good room -tem perature ductility.

On the shear modulus and thermal effects during structural relaxation of a model metallic glass:Correlation and thermal decoupling

Pd_(40)Ni_(40)P_(20)(at.%)samples with different enthalpy states were fabricated through high-pressure torsion or sub-Tg annealing of the as-cast material.Subsequently,the underlying structural relaxation was studied by in-situ shear modulus measurements and modulated differential scanning calorimetry.The results show that high-pressure torsion leads to shear modulus softening and an increase of the nonreversible exothermic enthalpy,indicating a significant structural rejuvenation,while sub-Tg annealing causes shear modulus hardening and a decrease of the nonreversible exothermic enthalpy.The reversible endothermic effect which can reflect the fractional change of supercooled liquid with temperature was found to be almost identical for all samples,and independent of deformation or thermal history.The total heat flow can be well correlated with the shear modulus within the framework of interstitialcy theory.Furthermore,we demonstrate that the structural relaxation below Tg decouples into internal stress relaxation andβ-relaxation.In addition,this work indicates that the processes ofα-relaxation andβ-relaxation in the metallic glass are of similar structural origin but occur on different spatial scales.

The effect of hydrogen on the recombination of Frenkel pair in tungsten： A theoretical insight

Tungsten (W), with its primary advantages, is considered as the most promising candidate for plasma facing materials (PFMs) for the next generation of fusion devices such as ITER. However, continuous bombardment with 14.1 MeV neutron introduces Frenkel defects as the primary damage in W [1]. The Frenkel defects, composed of self-interstitial atoms (SIAs) and vacancies, can develop to extended defects such as voids and interstitial clusters, resulting in hardening, swelling and embrittlement of W, thus degrading the properties of W [2]. The recombination of SIAs and vacancies is an effective way to reduce the Frenkel defects in bulk W, which enhances the radiation resistance of W based on recent theoretical calculations [3,4]. The moving of the SIA to the vacancy could finish the recombination process through instantaneous or thermally activated way [3]. The instantaneous recombination region is an ellipse with the semi-minor axis of 5.4 ? and semi-major axis of 18 ? according to the molecular dynamics calculation [4].