Many complex systems—such as telecom equipment,memory modules, optical systems, networking equipment,servers and base stations—use FPGAs and otherdigital ICs that require multiple voltage rails that muststart up and shut down in a specific order, otherwise theICs can be damaged. The LTC®2924 is a simple andcompact solution to power supply sequencing in a 16-pinSSOP package (see figures 1 and 2).
為了解決磁放大器性能測試過程中，需要對其供給不同數(shù)值恒定電流的問題，設(shè)計了一種基于DAC7512和單片機(jī)的數(shù)控恒流源系統(tǒng)。該系統(tǒng)采用AT89C51作為主控器件，將計算機(jī)發(fā)送的電流控制字命令轉(zhuǎn)換為D/A轉(zhuǎn)換器控制字，通過模擬SPI通信接口，寫D/A控制字到DAC7512，從而控制其輸出相應(yīng)數(shù)字電壓值，經(jīng)差動縮放電路、電壓/電路變換電路和功率驅(qū)動電路，最后輸出恒定電流。實驗結(jié)果表明，恒流源輸出電流調(diào)節(jié)范圍為-45~+45 mA、精度為±0.1 mA，分辨率達(dá)0.024 4 mA，具有應(yīng)用靈活，外圍電路簡單，可靠性高的特點。該數(shù)控直流恒流源也可為相關(guān)產(chǎn)品的測試系統(tǒng)研發(fā)提供參考。
Abstract:
In order to solve the need to supply different values constant current for the magnetic amplifier in testing process， numerical control constant current source system was designed based on DAC7512 chip and microcontroller technology. The system used the AT89C51 as the main chip， which can convert the current control word from computer into to D/A control words. And the system wrote D/A control word into the DAC7512 chip to control the output voltage value by the SPI communication interface， which can output corresponding constant current figures by scaling circuit， the V/I converter and power drive circuit. Experimental results show that the current source output current adjustment range is -45~+45mA， accuracy is ± 0.1mA， and resolution ratio is 0.024 4mA
it contains many classic Test Problems for Unconstrained Optimization such as camel6,treccani,goldstein,branin,
shubert1,Ackley,dejong,dejong1,dejong2,
dpower,rastrigin,Griewangk,Schwefel,
rosenbrock2 and step.
the package have the contour and mesh figures of these problem.
it also give m files of these problems,and
you can easily get your view of figures.
The present paper deals with the problem of calculating mean delays in polling systems
with either exhaustive or gated service. We develop a mean value analysis (MVA) to
compute these delay figures. The merits of MVA are in its intrinsic simplicity and its
intuitively appealing derivation. As a consequence, MVA may be applied, both in an
exact and approximate manner, to a large variety of models.
《為Windows Vista編寫安全的代碼》，2007年出版
Providing developers with first-hand insights into design decisions and practical advice for solving real-world security issues, this authoritative guide urges developers to write more secure code on the Vista platform to support a growing customer base.
Table of Contents
Writing Secure Code for Windows Vista
Foreword
Introduction
Chapter 1 - Code Quality
Chapter 2 - User Account Control, Tokens, and Integrity Levels
Chapter 3 - Buffer Overrun Defenses
Chapter 4 - Networking Defenses
Chapter 5 - Creating Secure and Resilient
Chapter 6 - Internet Explorer 7 Defenses
Chapter 7 - Cryptographic Enhancements
Chapter 8 - Authentication and Authorization
Chapter 9 - Miscellaneous Defenses and Security-Related Technologies
Index
List of figures
List of Tables
List of Sidebars
In this demo, I use the EM algorithm with a Rauch-Tung-Striebel smoother and an M step, which I ve recently derived, to train a two-layer perceptron, so as to classify medical data (kindly provided by Steve Roberts and Will Penny from EE, Imperial College). The data and simulations are described in: Nando de Freitas, Mahesan Niranjan and Andrew Gee Nonlinear State Space Estimation with Neural Networks and the EM algorithm After downloading the file, type "tar -xf EMdemo.tar" to uncompress it. This creates the directory EMdemo containing the required m files. Go to this directory, load matlab5 and type "EMtremor". The figures will then show you the simulation results, including ROC curves, likelihood plots, decision boundaries with error bars, etc. WARNING: Do make sure that you monitor the log-likelihood and check that it is increasing. Due to numerical errors, it might show glitches for some data sets.
the geometry of a diffraction grating, a common
illustration in textbooks of optics, spectroscopy, and analytical chemistry.
Sliders on the figures allow real-time interactive control of the incidence angle,
grating ruling density (lines/mm), wavelength, and diffraction order.
