ecos RTOS 原理介紹和應用開發The design philosophy of eCos was to augment an open-source RTOS (which meant no
per-unit royalties) with source-level con?guration tools that would enable embedded developers
to scale their RTOS from hundreds of bytes to hundreds of kilobytes without needing to manu-
ally change a line of source code.
Picking Up Perl is a freely redistributable tutorial book on Perl that can be downloaded in pdf, postscript, or textinfo format. It can also be viewed online in html format, either as one large file or as separate files for each chapter.
This gorgeous, full-color book will guide you through the complete design process, from getting inspiration and sketching ideas out, through to choosing a color scheme, designing the layout, and selecting effective imagery.
Throughout, the focus is on simple and practical techniques that anyone can use 鈥?you don鈥檛 need to have gone to art school or have artistic flair to create stunning designs using the methods outlined in this book.
You鈥檒l follow along as author and design guru Jason Beaird creates a complete web site layout using the techniques that you鈥檝e learned.
The book鈥檚 full-color layout and large format (8鈥?x 10鈥? make The Principles Of Beautiful Wed Design a pleasure to read.
Servomotors are available as AC or DC motors. Early servomotors were generally DC motors because the only type of control for large currents was through SCRs for many years. As transistors became capable of controlling larger currents and switching the large currents at higher frequencies, the AC servomotor became used more often. Early servomotors were specifically designed for servo amplifiers. Today a class of motors is designed for applica-tions that may use a servo amplifier or a variable-frequency controller, which means that a motor may be used in a servo system in one application, and used in a variable-frequency drive in another application. Some companies also call any closed-loop system that does not use a stepper motor a servo system, so it is possible for a simple AC induction motor that is connected to a velocity controller to be called a servomotor.
A Design and Implementation of The Online Shopping System
Abstract: Along with the development of the computer ,the database technique is widespread in the application of Internet, more and more , providing more thoughtful and humanized service for the large network customer. Characteristic services have already become gradually the current as the application of Wed nowadays. This text studied a method of project which composed of characteristic page and dynamic state of technical customer according to the data connection rule, compared with some projects that adopt already on present nets, this project have the advantage of providing customers more simple ,reflective obvious meticulous use and so on..
Find an introduction to the architecture, concepts and algorithms of the Linux kernel in Professional Linux Kernel Architecture, a guide to the kernel sources and large number of connections among subsystems.
Watermarking schemes evaluation
Abstract鈥擠igital watermarking has been presented as a solution to copy protection of multimedia objects and dozens of schemes and algorithms have been proposed. Two main problems seriously darken the future of this technology though.
Firstly, the large number of attacks and weaknesses which appear as fast as new algorithms are proposed, emphasizes the limits of this technology and in particu-lar the fact that it may not match users expectations.
Secondly, the requirements, tools and methodologies to assess the current technologies are almost non-existent. The lack of benchmarking of current algorithms is bla-tant. This confuses rights holders as well as software and hardware manufacturers and prevents them from using the solution appropriate to their needs. Indeed basing long-lived protection schemes on badly tested watermarking technology does not make sense.
The most straightforward approximation is the standard Gaussian approximation, where the MAI is approximated by a Gaussian random variable. This approximation is simple, however it is not accurate in general. In situations where the number of users is not large, the Gaussian approximation is not appropriate. In-depth analysis of must be applied. The Holtzman?s improved Gaussian approximation provides a better approximation to the MAI term. The approximation conditions the interference term on the operation condition of each user.
