Analysis of (k 0 ,k 1 ) clock-controlled sequences

Cryptographic sequence generators are discussed in which a linear feedback shift register (LFSR) is clock controlled in a pseudorandom manner by another register. A model of clock-controlled sequences is proposed. The necessary and sufficient condition guaranteeing the maximal linear complexity and the maximal period of such sequences is given. Two kinds of improved models having better statistical properties are given. In order to study the security of this model, three types of algebraic attacking algorithms are proposed. If the length of the second LFSR in such a model is large, the model can resist our algebraic attacks.     

Developing a New Security Framework for Bluetooth Low Energy Devices

Wearable devices are becoming more popular in our daily life. They are usually used to monitor health status, track fitness data, or even do medical tests, etc. Since the wearable devices can obtain a lot of personal data, their security issues are very important. Motivated by the consideration that the current pairing mechanisms of Bluetooth Low Energy (BLE) are commonly impractical or insecure for many BLE based wearable devices nowadays, we design and implement a security framework in order to protect the communication between these devices. The security framework is a supplement to the Bluetooth pairing mechanisms and is compatible with all BLE based wearable devices. The framework is a module between the application layer and the GATT (Generic Attribute Profile) layer in the BLE architecture stack. When the framework starts, a client and a server can automatically and securely establish shared fresh keys following a designed protocol; the services of encrypting and decrypting messages are provided to the applications conveniently by two functions; application data are securely transmitted following another protocol using the generated keys. Prudential principles are followed by the design of the framework for security purposes. It can protect BLE based wearable devices from replay attacks, Man-in-The-Middle attacks, data tampering, and passive eavesdropping. We conduct experiments to show that the framework can be conveniently deployed with practical operational cost of power consumption. The protocols in this framework have been formally verified that the designed security goals are satisfied.     

Structural design of a carbon fiber-reinforced polymer wheel for ultra-high speed grinding

Ultra-high speed grinding (UHSG) is receiving considerable attention owing to its ability to achieve high machining accuracy and productivity. The materials and design of the grinding wheels play a significant role in this technology. Wheels with steel bodies are currently widely used, but have deficiencies such as a large mass loading imposing on the spindle, along with high power consumption, large stress and deformation, and limited practical grinding wheel speed. Wheel bodies made of carbon fiber-reinforced polymer (CFRP) show promise for use in UHSG because of the low density and high specific strength of this material. The main aim of this paper is to carry out a structural design of a CFRP grinding wheel for UHSG. Comparisons of stress and deformation, dynamic characteristics, thermal deformation, and power consumption between steel and CFRP wheel bodies reveal the superior performance characteristics of CFRP. The design of the laminate structure of the CFRP is then optimized, considering various laminate processes. The abrasive layers are designed with regard to the number and thickness of segments. Finally, a CFRP wheel for UHSG is developed based on the design proposal.     

Novel bilateral-diffusion image encryption algorithm with compound chaos and LFSR

Abstract

In order to solve the problem of short cycle and low precision of one-dimensional (1D) chaotic function, the new compound two-dimensional chaotic function is presented by exploiting two 1D chaotic functions which are switched randomly. A new chaotic sequence generator is designed by the compound chaos and linear feedback shift register (LFSR). The random properties of compound chaotic functions and LFSR are also proved rigorously. The novel bilateral-diffusion image encryption algorithm and permutation algorithm are proposed based on the compound chaotic function and LFSR, which can produce more avalanche effect and larger key space. The entropy analysis, differential analysis, statistical analysis, cipher random analysis and cipher sensitivity analysis are introduced to test the security of new scheme. The results show that the novel image encryption method passes SP 800-22 standard tests and solves the problem of short cycle and low precision of 1D chaotic function.     

Automated Controller Placement for Software-Defined Networks to Resist DDoS Attacks

In software-defined networks (SDNs), controller placement is a critical factor in the design and planning for the future Internet of Things (IoT), telecommunication, and satellite communication systems. Existing research has concentrated largely on factors such as reliability, latency, controller capacity, propagation delay, and energy consumption. However, SDNs are vulnerable to distributed denial of service (DDoS) attacks that interfere with legitimate use of the network. The ever-increasing frequency of DDoS attacks has made it necessary to consider them in network design, especially in critical applications such as military, health care, and financial services networks requiring high availability. We propose a mathematical model for planning the deployment of SDN smart backup controllers (SBCs) to preserve service in the presence of DDoS attacks. Given a number of input parameters, our model has two distinct capabilities. First, it determines the optimal number of primary controllers to place at specific locations or nodes under normal operating conditions. Second, it recommends an optimal number of smart backup controllers for use with different levels of DDoS attacks. The goal of the model is to improve resistance to DDoS attacks while optimizing the overall cost based on the parameters. Our simulated results demonstrate that the model is useful in planning for SDN reliability in the presence of DDoS attacks while managing the overall cost.     

A Novel High-Speed Multiplexing IC Based on Resonant Tunneling Diodes

A new multiplexing IC based on the resonant tunneling diode (RTD) is proposed. The unique negative differential resistance characteristics arising from quantum effects of the RTD enable us to develop a new functional low-power digital circuit. The proposed multiplexing IC consists of two current-mode-logic monostable-bistable transition logic elements (CML-MOBILEs) based on the RTD and a low-power selector circuit block. The proposed circuit has been fabricated by using an InP RTD/ heterojunction bipolar transistor monolithic microwave integrated circuit technology. The multiplexing operation of the fabricated quantum effect IC has been confirmed up to 45 Gb/s for the first time as a monolithic technology based on the quantum effect devices. The dc power consumption is only 23 mW, which is found to be one-fourth of the current state-of-the-art conventional transistor-based multiplexing IC.     

Tool for Automated Instruction Set Characterization for Software Power Estimation

The complexity and functionality of mobile digital devices is continuously growing. This results in a higher energy consumption of such devices. To counteract this trend, it is mandatory to accomplish software power optimizations based on accurate power consumption models characterized for the processor. This paper presents an environment for automated instruction set characterization based on physical power measurements. The generic design of this characterization system enables an easy portability to other architectures. For an accurate current measurement, a high-performance sampling technique has been established, which can be either clock or energy driven. The performance of those techniques is analyzed, and the advantages over the conventional solution of a series resistor are discussed. During the characterization of different processor platforms, it could be shown that the characterization effort can be reduced from three man-months to two man-weeks.      

大面积高光学质量金钢石自支撑膜的制备

介绍了一种新型的磁控/流体动力学控制的大口径长通道直流电弧等离子体炬，并据此设计建造了100千瓦级高功率DC Arc Plasma Jet CVD金刚石膜沉积系统，讨论了该系统采用的半封闭式气体循环系统的工作原理，以及在气体循环条件下制备大面积高光学质量金刚石自支撑膜的研究结果。     

A glass/silicon technology for low-power robust gas sensors

Semiconductor gas sensors are devices based on metallic oxides that operate at high temperatures for achieving good sensitivities to the gases of interest. Silicon micromachined structures are often used as platforms for obtaining both high temperatures and low-power consumption at the same time. In this paper, a microstructure based on the combination of micromachined silicon substrates and glass wafers is presented. The device incorporates an array of four different thin-film gas sensors that, depending on the design, can operate at the same or at different temperatures. The designs have been optimized by the finite element method (FEM) and the geometrical parameters of the structure have been selected in order to reduce the power consumption. The full process fabrication is presented. It is based on the combination of bulk micromachining, glass structuring, anodic bonding, and sensitive material deposition. Electrical, thermal, and mechanical tests have been done to demonstrate that the devices show high robustness and can reach high temperatures with low-power consumption.     

Architectural design of a sensory node controller for optimized energy utilization in sensor networks

The increasing complexity of manufacturing machines and the continued demand for high productivity have led to growing applications of sensor networks to enable more reliable, timely, and comprehensive information gathering from the machines being monitored. An effective and efficient utilization of sensor networks requires new sensor designs that enable adaptive event-driven information gathering based on the condition of the machines, as well as a coordinated information distribution adjusted to the available communication bandwidth of the network. This paper investigates several fundamental aspects regarding the architectural design of a sensory node controller (SNOC). The SNOC is the key element in a large-scale sensor network that coordinates the operation of individual sensors and the communication among various sensing clusters to realize distributed intelligent sensing. A parametric SNOC design that dynamically adjusts the power supply and the data-acquisition procedure to reduce the overall energy consumption of the sensor network is presented. Considerations on both the hardware and software aspects of the design to achieve energy efficiency are described, and analytical formulations are derived. Simulation results for a sensor network consisting of 40 SNOCs, each coordinating eight physical sensors, have shown that the design is able to reduce the energy consumption by about 43%, as compared to traditional techniques. A prototype SNOC was designed and implemented, based on the platform of a commercially available microcontroller, and experimentally tested for its ability to dynamically adjust the power consumption. The study has provided a concrete input to the design optimization and experimental realization of an SNOC-based sensor network for machine-system monitoring.     

燃煤电厂脱硫废水辅助煤电解制氢

燃煤电厂脱硫工艺产生的脱硫废水具有高盐分、腐蚀性和结垢性等特点,是电厂废水处理中最难的一个环节。基于H型电解池对脱硫废水及其辅助煤电解的特性进行了研究,在脱硫废水资源化利用的同时吸纳燃煤电厂的过余电力。结果表明：脱硫废水经过酸化后电解性能明显高于水,可以降低电解制氢的电耗;仅脱硫废水不能促进煤的电氧化,仍需要添加部分铁离子作为催化剂,但未经酸化的脱硫废水可以促进铁离子的催化作用,从而进一步降低电解制氢的电耗。基于此,提出了酸化处理、直接利用和添加煤粉3种可能的电解脱硫废水制氢的工艺手段。     

Phased-ultrasonic receiving-planar array transducer for partial discharge location in transformer

Partial discharge (PD) location in transformers is very important, and many methods that have been brought forward in past decades have a limitation theoretically, namely, they cannot locate multiple PDs in electrical equipment. In this paper, a new PD location method based on UHF and ultrasonic-phased arrays receiving theory has been presented, which has a possibility to locate multiple PDs. According to the method, a phased-ultrasonic receiving-planar array sensor that possesses 16 * 16 elements is designed; and, based on the phased-array theory, the characteristics of the plane sensor are studied. The laboratory experimental tests on the plane sensor element indicates that it has a good performance within the frequency band of the main ultrasonic energy produced by PD in transformer oil. Location tests are conducted on one or two piezoelectric ultrasonic sources in oil, which are both simulated as PD sources and triggered by an electrical pulse whose front is considered as a time benchmark in the locating algorithm. The test results show locations to one and two PDs can be realized in a single measurement, which lays a foundation for locating PDs in a power transformer in service.     

Magnetic force control with composite of giant magnetostrictive and piezoelectric materials

We propose a new magnetic force control device, composed of a giant magnetostrictive material (Terfenol-D) and a piezoelectric material (PZT), for coilless magnetic force control. The device uses the inverse magnetostrictive effect, whereby the variation of magnetization of a Terfenol-D rod controlled by PZT is converted to the variation of magnetic force by a magnetic circuit. Because PZT is electrically capacitive, the method has the advantage of low power consumption and low heat generation in static operation. We have fabricated several devices with different geometrical shapes of the rods and magnetic yokes, and we describe their characteristics such as power consumption, heat generation, and response. We discuss a magnetic circuit design strategy that uses the /spl Delta/E effect in magnetostrictive materials to increase the energy conversion efficiency.     

Design of a Low-Power Micromachined Fluxgate Sensor Using Localized Core Saturation Method

Design of a low-power micromachined ring-type flux- gate sensor with localized saturation cores has been made and optimized in this work. The design is accomplished by using the electromagnetic simulation software, Magnet^TM, which is capable of establishing a quantitative connection between the sensor parameters and the geometrical parameters of the model. Using recently developed data extraction techniques, the design with low power (19 mW) and high sensitivity (590 V/T at 60 muT) can be achieved after a series of simulations. For comparison, an actual device has been fabricated with sensitivity of 650 V/T at 60 muT, power consumption of 14 mW. The good agreement between the simulation and the experimental results validate our new approach for the design of low-power fluxgate. In addition, measurements using a second-harmonics-based detection circuit have been performed so that the noise, stability, and perming effect of the fabricated device are explored.     

Vacancy‐Induced Synaptic Behavior in 2D WS2 Nanosheet–Based Memristor for Low‐Power Neuromorphic Computing

Memristors with nonvolatile memory characteristics have been expected to open a new era for neuromorphic computing and digital logic. However, existing memristor devices based on oxygen vacancy or metal‐ion conductive filament mechanisms generally have large operating currents, which are difficult to meet low‐power consumption requirements. Therefore, it is very necessary to develop new materials to realize memristor devices that are different from the mechanisms of oxygen vacancy or metal‐ion conductive filaments to realize low‐power operation. Herein, high‐performance and low‐power consumption memristors based on 2D WS₂ with 2H phase are demonstrated, which show fast ON (OFF) switching times of 13 ns (14 ns), low program current of 1 µA in the ON state, and SET (RESET) energy reaching the level of femtojoules. Moreover, the memristor can mimic basic biological synaptic functions. Importantly, it is proposed that the generation of sulfur and tungsten vacancies and electron hopping between vacancies are dominantly responsible for the resistance switching performance. Density functional theory calculations show that the defect states formed by sulfur and tungsten vacancies are at deep levels, which prevent charge leakage and facilitate the realization of low‐power consumption for neuromorphic computing application.     

Assessment of information impacts in power system security against malicious attacks in a general framework

In the analysis of power systems security, recently a new concern related to possible malicious attacks caught much attention. Coordination among different transmission system operators (TSO) in an interconnected power system to counteract such attacks has become an important problem. This paper presents a general framework for describing the physical, cyber and decision-making aspects of the problem and their interrelations; within this framework, an analytic tool for the assessment of information impacts in handling on-line security after a malicious attack is proposed and discussed. The model is based on the socially rational multi-agent systems and the equilibrium of a fictitious play is considered to analyze the impacts of various levels of information available to the interconnected system operators on the outcomes of the decision-making process under attack. A 34-buses test system, with 3 systems interconnected by tie-lines, is presented to illustrate the model and compare the impacts of different information scenarios.     

Power Pinch Analysis supply side management: strategy on purchasing and selling of electricity

Pinch analysis concept has been recently stepped into the realm of design and optimisation of power systems. One well-established pinch analysis that has been used in power systems design and optimisation is called Power Pinch Analysis (PoPA). In PoPA, both graphical and numerical approaches have provided an insight on the systematic approach to target and design various power systems. By only visualising the minimum amount of outsource energy required by the power system, the graphical PoPA method as a whole does not show the purchasing of outsource energy based on the exact time intervals. Using graphical PoPA, the objective of this study is to determine a proper strategy to buy and sell outsource electricity to improve the overall performance of a hybrid power system comprising renewable power generators and energy storage system. The strategies are made based on three design parameters: energy-related capacity, power-related capacity of energy storage and maximum grid power rating between centralised grid and hybrid power system. While deciding on the best strategy and heuristics to be implemented, the effects on system operation and economy are indirectly analysed. It is experimented that the output can benefit electricity consumers or producers.     

An improved differential power analysis against random process interrupts

In this paper, we propose an improved differential power analysis (DPA) attack method for use against the 128-bit Advanced Encryption Standard (AES-128) with random process interrupt (RPI) protection applied on a field-programmable gate array (FPGA). The misalignment caused by RPIs is undermined by the new signals processed by our proposed method. Our method uses compressed energy entropy and the sliding window technique to process the power consumption curves (PCCs). The results of our experiments show that by gathering the scattered information, our method has excellent performance on the DPA attacks. Compared with existing methods, our proposed method shows better performance in increasing the amplitude of the maximum spike of the correlation curve. While achieving the same success rates, the number of PCCs applied in our method has decreased by 35%.     

Hybrid Optical Image Converters Based on InSb-MDS Structures for the Medium-Frequency Infrared Band

Results of a comparative investigation of image sensors based on metal-dielectric-semiconductor (MDS) structures and on photodiodes are presented. The noise characteristics, sensitivity, power consumption, and overall dimensions of the two types of image sensors are compared. It is shown that InSb-MDS structures are promising for the design of solid-state hybrid image sensors in the medium infrared range of wavelengths.     

Screw-Type Windmills and Their Particular Features

A new type of windmill based on a screw-type wind receiver has appeared recently. In the present article, the principles of operation of screw-type windmills and their geometric characteristics are discussed. Attention is given to the design and technology of manufacture of a screw-type rotor; possible arrangements of wind-power plants with a screw-type rotor are shown. The procedure of calculation of the power characteristics is substantiated. Screw-type windmills are noiseless and environmentally safe; they show promise as the least expensive ones.