非理想信道下基于人工噪声的密集异构蜂窝网安全传输方案

针对密集异构蜂窝网在非理想信道状态信息条件下的安全传输问题,该文分析了人工噪声对通信的可靠性和安全性的影响,在此基础上提出功率分配优化模型,在不同信道估计精度条件下给出了最优的功率分配因子。首先,考虑信道估计误差对合法信号传输以及人工噪声泄露的影响,推导了典型通信链路的连通中断概率和安全中断概率。然后,在安全性和可靠性约束条件下建立功率分配优化模型以最大化系统安全吞吐量,并通过K维联合搜索算法得到每层网络的最优功率分配因子。最后,仿真结果表明系统设置最优功率分配因子时,人工噪声方案可提升约15%的安全吞吐量。     

一种改进的物理光学迭代法

该文使用线积分形式的Kirchhoff公式替代F.Obelleiro(1995)提出的物理光学迭代(IPO)法中的经典Kirchhoff公式,提出了一种改进的IPO法。数值计算结果表明,改进的IPO法和FObelleiro(1995)的IPO法比较,对三面角反射器、飞机座舱等大口面凹型腔体的电磁散射特性分析,在数值精度相当的情况下,计算速度明显提高。     

基于人工神经网络特征向量提取的FF-APUF攻击方法

为评估物理不可克隆函数(PUF)的安全性,需针对不同的PUF结构设计相应的攻击方法.该文通过对强PUF电路结构和工作机理的研究,利用人工神经网络(ANN)提出一种针对触发器-仲裁器物理不可克隆函数(FF-APUF)的有效攻击方法.首先,根据FF-APUF电路结构,利用多维数组构建电路延时模型;然后,对FF-APUF的二...     

FPGA-based Physical Unclonable Functions: A comprehensive overview of theory and architectures

Physically Unclonable Functions (PUFs) are a promising technology and have been proposed as central building blocks in many cryptographic protocols and security architectures. Among other uses, PUFs enable chip identifier/authentication, secret key generation/storage, seed for a random number generator and Intellectual Property (IP) protection. Field Programmable Gate Arrays (FPGAs) are re-configurable hardware systems which have emerged as an interesting trade-off between the versatility of standard microprocessors and the efficiency of Application Specific Integrated Circuits (ASICs). In FPGA devices, PUFs may be instantiated directly from FPGA fabric components in order to exploit the propagation delay differences of signals caused by manufacturing process variations. PUF technology can protect the individual FPGA IP cores with less overhead. In this article, we first provide an extensive survey on the current state-of-the-art of FPGA based PUFs. Then, we provide a detailed performance evaluation result for several FPGA based PUF designs and their comparisons. Subsequently, we briefly report on some of the known attacks on FPGA based PUFs and the corresponding countermeasures. Finally, we conclude with a brief overview of the FPGA based PUF application scenarios and future research directions.     

Energy policy implications of waste management in various sectors of the economy—An analysis based on physical systems theory

This paper aims to bring into focus the impact of waste management in different sectors of the economy on some important policy issues related to energy. In a multi-sector economy, the total energy demand consists of the direct energy demand of human population, the intermediate demand of other sectors and the energy wastes which cannot be recycled and have to be rejected to nature. These sectorial interlinkages in the economy, due to their cascading effects, are very important for studying the real impact of waste generation or waste recycling on the energy demand and prices. A generalized multi-sector economy model which combines the concepts of input-output economics with waste management (input-output-waste model) has been developed based on physical systems theory. The results of sensitivity analysis of this model are presented in this paper, which suggest the need to have a serious look into waste management practices in all sectors of the economy from an energy policy point of view.     

A PRACTICAL METHOD FOR RECTIFYING INTERFACIAL TENSION DATA TO PREDICT THE SHAPE OF INTERFACES IN AN IMMISCIBLE LIQUID/LIQUID/GAS SYSTEM

The shape of interfaces formed by the contact of two liquid phases, immiscible with each other, and a gaseous phase can be predicted on the condition that the tension to work at each interface is known with a sufficient accuracy. In general, interfacial tension data available are not so accurate, however, as to be useful as they are in predicting the shape of interfaces, particularly when the spreading coefficient of either liquid (liquid 1) on the other (liquid 2) has a negative value of a small magnitude. Presented in this note is a simple method to rectify the interfacial tension data, with the aid of a measurement of the radius of a lens of liquid 1 of a known volume placed on the horizontal surface of liquid 2, and thereby make them usable for predicting interfacial geometries. The method is tested by applying it to benzene/water and n-pentane/water systems.     

Crosstalk-aware multi-bit flip-flop generation for power optimization

Applying multi-bit flip-flops (MBFFs) for clock power reduction in modern nanometer ICs has been becoming a promising lower-power design technique. Many previous works tried to utilize as more MBFFs with larger number of bits as possible to gain more clock power saving. However, an MBFF with larger number of bits may lead to serious crosstalk due to the close interconnecting wires belonging to different signal nets which are connected to the same MBFF. This paper analyzes, evaluates, and compares the relationship between power consumption and crosstalk when applying MBFFs with different numbers of bits. To solve the addressed problem, a novel crosstalk-aware power optimization approach is further proposed to optimize power consumption while satisfying the crosstalk constraint. Experimental results show that the proposed approach is very effective in crosstalk avoidance when applying MBFFs for power optimization.     

Implementation of pseudo-linear feedback shift register-based physical unclonable functions on silicon and sufficient Challenge–Response pair acquisition using Built-In Self-Test before shipping

We implemented pseudo-linear feedback shift-register-based physical unclonable functions (PL-PUFs) on silicon and analyzed their performances in terms of reproducibility, uniqueness, and resistance to machine-learning attacks. A PL-PUF is compact and high-throughput PUF, slightly oversensitive to voltage fluctuations. To overcome this drawback, we developed a capturing signal generation circuit that was tolerant to the reproducibility degradation caused by supply voltage changes. We also implemented a Built-In Self-Test (BIST) circuit with an irreversible destruction mechanism to enable exceedingly fast challenge–response pairs (CPRs) for the PUFs before shipping. After the CPRs were evaluated, the BIST circuit became invulnerable to exploitation by attackers.     

BeO瓷的金属化和封接

综述了氧化铍瓷的金属化及其封接技术,指出氧化铍瓷和Al2O3瓷在金属化工艺上的差异,论文最后汇集了国内外常用烧结金属粉末法15种配方和工艺参数,以资同行专家参考.     

Scheduling with interference decoding: Complexity and algorithms

In this article we study the problem of scheduling wireless links in the physical interference model with interference decoding capability. We analyze two models with different decoding strategies that explore the fact that interfering signals should not be treated as random noise, but as well-structured signals. The first model makes use of successive interference cancelation, which allows the strongest signal to be iteratively decoded and subtracted from a collision, thus enabling the decoding of weaker simultaneous signals. The second model explores the fact that routers are able to forward the interfered signal of a pair of nodes that wish to exchange a message and these nodes are able to decode the collided messages by subtracting their own contribution from the interfered signal. We prove that the scheduling problem remains NP-complete in both models. Moreover, we propose a polynomial-time scheduling algorithm that uses successive interference cancelation to compute short schedules for network topologies formed by nodes arbitrarily distributed in the Euclidean plane. We prove that the proposed algorithm is correct in the physical interference model and provide simulation results demonstrating the performance of the algorithm in different network topologies. We compare the results to solutions without successive interference cancelation and observe that considerable throughput gains are obtained in certain scenarios.