A New NTRU-Type Public-Key Cryptosystem over the Binary Field

As the development of cloud computing and the convenience of wireless sensor netowrks, smart devices are widely used in daily life, but the security issues of the smart devices have not been well resolved. In this paper, we present a new NTRU-type public-key cryptosystem over the binary field. Specifically, the security of our scheme relies on the computational intractability of an unbalanced sparse polynomial ratio problem (DUSPR). Through theoretical analysis, we prove the correctness of our proposed cryptosystem. Furthermore, we implement our scheme using the NTL library, and conduct a group of experiments to evaluate the capabilities and consuming time of encryption and decryption. Our experiments result demonstrates that the NTRU-type public-key cryptosystem over the binary field is relatively practical and effective.     

一种基于地图爬虫的场景边界识别与质量监控方法

本文提出了一种基于地图爬虫的场景边界识别与质量监控方法，参考互联网爬虫技术实现场景边界自动识别，依靠“MR+OTT”和“帕累托法则”实现场景资源信息自动更新，在此基础上，关联网优大数据实现重点场景网络质量的智能预警监控。在某市进行试点，方案上线后自动识别场景4361处，实现场景小区自动更新，初次评估覆盖率92.85%，经过两个月的整治，覆盖率提升至94.22%，弱覆盖小区占比下降4.72PP。     

Manganese ferrite-polyaniline hybrid materials: Electrical and magnetic properties

Magnetic MnFe₂O₄ nanopowders were synthesized by an original solvothermal method in the absence and in the presence of tetra-n-butylammonium bromide (TBAB) and Tween 80 (TW) as surfactants. Manganese ferrite/polyaniline (PANI) hybrid materials were synthesized by in situ polymerization of aniline on the surface of MnFe₂O₄ using ammonium persulfate as oxidant. The purpose of the study was to investigate the influence of the two surfactants on the properties of the MnFe₂O₄ powders and of their composites with PANI. The specific surface area, the cumulative surface area of pores and the cumulative volume of pores are influenced by the nature of surfactant in case of MnFe₂O₄ powders and are higher by comparison to those of the MnFe₂O₄/PANI hybrid materials. The values of saturation magnetization in case of MnFe₂O₄ powders are higher than those of the hybrid materials and are not influenced by the surfactant nature. These features revealed that MnFe₂O₄ powders can be efficiently used as adsorbents for the purification of wastewaters. The values of the electrical conductivity of the composites exhibit a significant increase in comparison to the MnFe₂O₄ powders and depend on the surfactant nature. The highest value of electrical conductivity was achieved by the composite obtained using Tween 80 as surfactant (σ_DC = 54.5·10^?5S?m^?1) which was close to that of PANI (σ_DC = 61.2·10^?5 S?m^?1). The fact that the magnetic and electric properties of the synthesized MnFe₂O₄/PANI composites can be changed by design, demonstrate the high potential of these materials to be used in magneto-electric applications.     

Distance Estimation and Material Classification of a Compliant Tactile Sensor Using Vibration Modes and Support Vector Machine

Many animals possess actively movable tactile sensors in their heads, to explore the near-range space. During locomotion, an antenna is used in near range orientation, for example, in detecting, localizing, probing, and negotiating obstacles. A bionic tactile sensor used in the present work was inspired by the antenna of the stick insects. The sensor is able to detect an obstacle and its location in 3D (Three dimensional) space. The vibration signals are analyzed in the frequency domain using Fast Fourier Transform (FFT) to estimate the distances. Signal processing algorithms, Artificial Neural Network (ANN) and Support Vector Machine (SVM) are used for the analysis and prediction processes. These three prediction techniques are compared for both distance estimation and material classification processes. When estimating the distances, the accuracy of estimation is deteriorated towards the tip of the probe due to the change in the vibration modes. Since the vibration data within that region have high a variance, the accuracy in distance estimation and material classification are lower towards the tip. The change in vibration mode is mathematically analyzed and a solution is proposed to estimate the distance along the full range of the probe.     

A Straightforward Direct Traction Boundary Integral Method for Two-Dimensional Crack Problems Simulation of Linear Elastic Materials

This paper presents a direct traction boundary integral equation method (DTBIEM) for two-dimensional crack problems of materials. The traction boundary integral equation was collocated on both the external boundary and either side of the crack surfaces. The displacements and tractions were used as unknowns on the external boundary, while the relative crack opening displacement (RCOD) was chosen as unknowns on either side of crack surfaces to keep the single-domain merit. Only one side of the crack surfaces was concerned and needed to be discretized, thus the proposed method resulted in a smaller system of algebraic equations compared with the dual boundary element method (DBEM). A new set of crack-tip shape functions was constructed to represent the strain field singularity exactly, and the SIFs were evaluated by the extrapolation of the RCOD. Numerical examples for both straight and curved cracks are given to validate the accuracy and efficiency of the presented method.     

Effect of metal-hydride hydrogen activation on longitudinal yield of negative ions from PIG

We present the results of the study of activated hydrogen, desorbed from a metal hydride cathode, effect on a PIG ability to emit negative hydrogen ions H^? in the longitudinal direction. It becomes possible due to a change in the discharge properties with the further output of negatively charged particles together with positive ions along the magnetic field. The separation of negative ions from an extracted flow of charged particles was carried out by an electromagnetic filter. The efficiency of the filter was investigated and the optimal external parameters for H^? ions separation were determined. The beam current of H^? ions has been obtained at the level of 5 mkA at an average discharge current 2 mA and a discharge voltage 5 kV.     

SENSITIVITY ANALYSIS AND OPTIMIZATION OF ELASTIC-PLASTIC STRUCTURES

Elastic-plastic analysis problems formulated as quadratic programming problems involve energy functional and equilibrium and yield constraints that depend on the design, material and loading. In this paper we consider the problem of determining the variation of structural response with respect to variations of these parameters. A general result for discrete structures is presented and implications for optimal design are discussed.     

A RECONSTRUCTION OF THE KEY TO BEALE CIPHER NUMBER TWO

A reconstruction of the key used to encrypt B2 (Beale Cipher Number 2) reveals greater statistical anomalies in Bl than previously reported by Gillogly [8]. The 1885 pamphlet versions of the ciphers are used in this analysis. Several explanations of these anomalies are discussed. The application of artificial intelligence techniques to automated cryptanalysis of the Beale Ciphers is discussed.     

A STATISTICAL ATTACK ON THE RUNNING KEY CIPHER

The frequencies of n-graphs, groups of n letters, for n as large as 6 are compiled and used to launch a statistical attack on a running key cipher. Programs written in C++ make the calculations possible. The results of the attack for various values of n are analyzed.     

Explicit dynamics of space free-flyers with multiple manipulators via SPACEMAPLE

This paper focuses on the dynamics of a multiple manipulator space free-flying robot (SFFR) with rigid links and issues relevant to the development of appropriate control algorithms. To develop an explicit dynamics model of such complex systems, the Lagrangian formulation is applied. First, the system kinetic energy is derived based on a developed kinematics approach. Then, through vigorous mathematical analyses, three formats are obtained which describe the contribution of each term of kinetic energy to the equations of motion. Next, explicit derivations of a system's mass matrix, and of the vectors of non-linear velocity terms and generalized forces are introduced for the first time. The obtained dynamics model is very useful for dynamics analyses, design and development of control algorithms for such complex systems. The explicit SFFR dynamics can be implemented either numerically or symbolically. Following the latter approach, the developed symbolic code for dynamics modeling, i.e. SPACEMAPLE, and its verification procedure are described, and issues relevant to the development and computation of dynamics models in control algorithms are briefly discussed. Specific dynamic characteristics of SFFRs compared to fixed-base manipulators are pointed out.