汽车制造商拥抱48V轻混系统

全球的汽车制造商已经开始推出采用新48V电源子系统的汽车.本文就48V电源子系统相关性能及系统优势进行了详细介绍,同时介绍了一款12V/48V电源系统及双向DC/DC同步PWM控制器ISL78226.     

Wavelets and statistical analysis of functional magnetic resonance images of the human brain

Wavelets provide an orthonormal basis for multiresolution analysis and decorrelation or 'whitening' of nonstationary time series and spatial processes. Wavelets are particularly well suited to analysis of biological signals and images, such as human brain imaging data, which often have fractal or scale-invariant properties. We briefly define some key properties of the discrete wavelet transform (DWT) and review its applications to statistical analysis of functional magnetic resonance imaging (fMRI) data. We focus on time series resampling by 'wavestrapping' of wavelet coefficients, methods for efficient linear model estimation in the wavelet domain, and wavelet-based methods for multiple hypothesis testing, all of which are somewhat simplified by the decorrelating property of the DWT.     

A SystemC library for specifying pipeline abstractions

We describe a SystemC library for specifying, modeling, and simulating hardware pipelines. The library includes a set of overloaded operators defining a pipeline expression language that allows the user to quickly specify the architecture of the pipeline. The pipeline expression is used to derive the connectivity of the SystemC modules that define the stages of the pipeline and to automatically insert latches and control modules between the stages to handle the proper routing of transactions through pipeline. Using the SystemC simulator the pipeline can then be simulated and evaluated. The pipeline expression language sits on top of SystemC, exposes all of the features of C++ and SystemC enabling the user to specify, evaluate, and analyze pipeline architectures.     

Hey! You! Get Off of My Cloud

ABSTRACT

Internet documents are generally created with the sweeping assumption that hypertext's characteristics make for better reading. However, one type of reading does not fit all genres of writing. In fact, how people go about reading hypertext is a largely unanswered question. This essay examines whether hypertext syllabi discourage reading and discourage searching the Internet by suggesting to students that all they need is linked to the syllabus. Specifically, the essay examines a syllabus called “Ethics and the Internet” by Wendy Robinson at Duke University to see how some pages lend themselves to reading, and how others do not.     

Multi-objective optimisation of bijective s-boxes

In this paper we investigate the heuristic construction of bijective s-boxes that satisfy a wide range of cryptographic criteria including algebraic complexity, high nonlinearity, low autocorrelation and have none of the known weaknesses including linear structures, fixed points or linear redundancy. We demonstrate that the power mappings can be evolved (by iterated mutation operators alone) to generate bijective s-boxes with the best known tradeoffs among the considered criteria. The s-boxes found are suitable for use directly in modern encryption algorithms. Joanne Fuller, Ph.D.: She is a research associate at the Information Security Institute of Queensland University of Technology in Brisbane, Australia. She received her Ph.D. from out in 2004. William Millan, Ph.D.: He is a postdoctoral research fellow at the Information Security Institute of Queensland University of Technology in Brisbane, Australia. He pioneered the use of Evolutionary Computation techniques to develop new cryptographic primitives, notably new Boolean functions and S-boxes for block and stream ciphers, and has published many papers in this area. Ed Dawson, Ph.D.: He is the Director of the Information Security Institute of Queensland University of Technology in Brisbane, Australia. He has published more than 200 papers in Crypto conferences and Journals. He has served as Program Committee Member for more than 50 International Conferences in Cryptology and Network Security. He is currently a member of the Board of Directors of International Association for Cryptologic Research (IACR).     

GHZ polarization dynamics in ferroelectric thin films

Abstract

We present results from experiments which measure the local dielectric response of ferroelectric thin films driven by microwave-frequency electric fields. The repetition rate of a mode-locked Ti:Sapphire laser is used to generate a microwave drive signal that is phase-locked to an optical probe pulse and applied to the ferroelectric thin film. The induced polarization change in the ferroelectric film is measured stroboscopically via the electro-optic effect. Polarization images are acquired by scanning the laser beam across the sample in a confocal geometry. Time resolution is achieved by changing the delay between the electrical pump and the optical probe. Initial results show large local phase shifts in the ferroelectric response of closely separated regions of a Ba_0.5Sr_0.5TiO₃ thin film. This new experimental technique may help to understand the physical mechanisms of dielectric loss in these materials.     

Intraindividual variability in affect: Reliability, validity, and personality correlates.

This article gives an overview of previous work on affect variability, discusses the methodological shortcomings of research on affect variability, and presents the results of an empirical study of intraindividual variability in primary emotions across time. The results of a daily assessment study using structural equation modeling and nonlinear regression analyses showed that intraindividual variability in affect is a multidimensional construct that is sufficiently stable to be considered a psychological trait and can be reliably measured by the intraindividual standard deviation. Intraindividual variability showed convergent validity with mean level scores and neuroticism but was sufficiently distinct to be considered a unique trait. This was particularly true of intraindividual variability in positive emotions; only about 10% of the variance could be accounted for by mean affect levels and the variables of the 5-factor model of personality. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Cache consistency by design

Summary. In this paper we present a proof of the sequential consistency of the lazy caching protocol of Afek, Brown, and Merritt. The proof will follow a strategy of stepwise refinement, developing the distributed caching memory in five transformation steps from a specification of the serial memory, whilst preserving the sequential consistency in each step. The proof, in fact, presents a rationalized design of the distributed caching memory. We will carry out our proof using a simple process-algebraic formalism for the specification of the various design stages. We will not follow a strictly algebraic exposition, however. At some points the correctness will be shown using direct semantic arguments, and we will also employ higher-order constructs like action transducers to relate behaviours. The distribution of the design/proof over five transformation steps provides a good insight into the variations that could have been allowed at each point of the design while still maintaining sequential consistency. The design/proof in fact establishes the correctness of a whole family of related memory architectures. The factorization in smaller steps also allows for a closer analysis of the fairness assumptions about the distributed memory.     

先进运动技术助飞机涂装师一臂之力

随着飞行器对象建模技术的改进以及控制技术的提高．Boeing公司最新的飞机涂装系统能够在确保不发生接触的前提下,将涂装人员吊送到与飞机间隔4英寸之内的位置进行操作。     

Collaboration planning framework (CPF) to support distributed product development

Current marketplace is undergoing major changes that will affect the way organizations conduct their business. Organizations need to respond to a geographically dispersed marketplace. This can be achieved by leveraging globally distributed resources to fully understand and interpret individual customer needs. That is, organizations need to integrate their operations (product development) in a way that will allow dynamic response to market changes. Computer-supported collaborative engineering could provide the integrating mechanisms needed to integrate distributed operations. The change to collaborative engineering should be based on sound and comprehensive methodologies that can analyze current practices, assess their ability to be performed collaboratively, restructure organizational practices to enhance their performance in a collaborative environment, select appropriate tools to support practices, and provide an implementation plan. This paper presents a framework to build computer-supported collaborative product design and development operating in a distributed environment. The framework is composed of six modules that provide a systematic procedure to plan for computer supported collaborative engineering.