安卓系统与IOS系统比较—英文文献翻译外文翻译

ESEP 2011: 9-10 December 2011, Singapore

An Analysis and Comparison of Open and Closed Mobile

Platforms

Android vs. iPhone

Yinglu ZOUa, , Hao WU b, Jianxin HUANG a,b

a Information Engineering College,7 JianXue Road, JinShui District, ZhengZhou,

450001, China

Abstract

With the release of Android 2.2 Froyo and iPhone 4, the war between open and closed mobile platforms tends to befiercer. Being the representatives of the two parties, Froyo and iOS 4 are quite different at system framework, newfeature, application market and integration model. According to the company spirits of Google and Apple, we do some analyses and comparisons of the above points, explain the differences of Android and iPhone from the shallower to the deeper, then conclude the characteristics of open and closed mobile platforms, aiming at providing an objective reference for researchers of mobile platforms, helping them see clearer into mobile industry. As a result,both Froyo and iOS 4 have their advantages and disadvantages, still they are far from being perfect, there?s room forfurther improvement.

Keywords: Android；iPhone；Froyo；iOS 4；smart phone；mobile platform

1. Introduction

In recent years, the popularity of smart phone kept going up. More and more smart phones are sold anda lot of people are embracing them. Smart phones brought great convenience to users, as well created opportunities for smart phone researchers. That?s to say, the wide spread of smart phones benefited both sides. At the same time, developing of smart phone OS becomes one of the smartest industry. To be a smart phone OS, the system should: 1. Provide services like a PC. 2. Work with a GPU for better visual effects. 3. Allow the user to surf on Internet freely. And apparently, there?re also some weaknesses:1.Limited batte ry. 2. Poor CPU performance against PC CPU. 3. Small storage. 4. The use of RAM may leads to loss of data when the phone runs out of battery

Now the 2 giants of smart phone OS are Android and iPhone OS. On one side, Android is based on Linux kernel and Dalvik virtual machine, and it is open sourced. The upper layer of Android is Java based,allowing developers to develop Android applications with Google SDK and sell their software in Android Market. On the

other side, iPhone OS, which bases on Unix kernel and Darwin model but is closed sourced,evolves from Mac OS X and is the default OS of iPhone, iPod Touch and iPad. Objective C based software can run in iPhone OS, and just like Android, you can develop your own iPhone applications and upload them onto Apple?s …App Store? for sale [1] [2] [3] [4].

By comparing the latest Android and iPhone OS, Android 2.2 Froyo and iOS 4, we can take a glimpse at the main feature of open and closed smart phone OSs. While the 2 OSs are designed in rather different mentality an d functionality, it?s a little early to tell which one is better.

2. Smart Phone OS

2.1. Android

The system architecture of Android consists of 5 layers, which are Linux Kernel, Android Runtime, Libraries, Application Framework and Applications, from bottom to top.

Android provides core services like security, memory management, process management, network stack and drivers, basing on Linux 2.6. Being the abstract layer between software and hardware, the layer of Linux Kernel hides the implementing details of hardware and provides integrated services for upper layer.

Dalvik virtual machine and Java core libraries are included in the layer of Android Runtime, providing most functions in Java core libraries.

The layer of Libraries contains a class of C/C++ libraries for Android components. Those libraries are integrated by the layer of Application Framework and then provided to developers.

The layer of Application Framework provides all kinds of modules for program initialization to simplify the use of components, allowing developers do whatever they want and provide services for other softwares, under the limitation of security, of course.

Mainstream applications are located in the layer of Application, including e-mail, SMS, calendar, Google map, Web browser and contacts. Users interact directly with this layer [1] [2].

The latest version of Android, Android 2.2 Froyo, puts on some new features. They are: 1. Support Flash 10.1, enables user to watch flash on the phone. 2. V8 JavaScript engine in web browser leads to faster Internet data transportation. 3. Big advance in network sharing. You can use the phone as a 3G NIC,or convert 3G signal

to Wi-Fi. 4. Automatically software update. 5. Softwares can be setup in SD card to extend file storages.

2.2. iPhone

iPhone OS is consist of 4 abstract layers: Core OS, Core Service, Media and Cocoa Touch respectively.

Layers of Core OS and Core Service are designed in C language to handle core system services, enabling developers to perform file access, sockets calling and data handling. CFNetwork and SQLite are also parts of these 2 layers.

The layer of Media, according to its name, this layer is used to control video and audio, as well handle 2D and 3D images. The Open GL-ES Quratz part of the layer is coded with C language, while the part of Core-Audio and Core-Animation is Objective C based.

The layer of Cocoa Touch builds a basic framework for all kinds of programs in iPhone. Most programs run in Cocoa Touch layer, and it?s surely Objective C based [3] [4].

The latest iPhone OS is iOS 4. It includes the following new features: 1.Software classification. This

feature enables user to place sorted softwares into different documents, making it clearer to manage. 2. Email integration. One account is for all e-mails from different providers. 3. iBook, originally from iPad, is built in iOS. 4. A brand new Apple Game Center makes iPhone a tremendous entertainment platform.

2.3. Android vs. iPhone

Being the top 2 smart phone OSs, we?re sure that both Android and iPhone have their own advantages and disadvantages. Now let?s take a look at each of them, and see what unique feature they have.

Android 2.2 Froyo fully support multitask, which means you can listen to music while writing blog. And iOS 4, officially announced to be …multitasked?, is in fact a play of concept. Only a few of softwares which are authorized by Apple can run …simultaneously?, whose principle is much easier that multitask:when an application is switched out, its current state is saved and then the system just closes it. And when it?s switched in, we?re back to the previous snapshot [5] [6] [7].

During the publication of Android 2.2 Froyo, Google announced it has …the most fluent web browser?,because the use of V8 JavaScript engine. V8 is a brand new engine, designed for running big size JavaScript application. In some kind of tests, V8

is much faster than JScript from Internet Explorer, SpiderMonkey from Firefox and JavaScriptCore from Safari. It all owe to 3 key parts of V8, they?re fast attribute access, dynamic code generation, effective trash cleaning.

2.3.1. Fast Attribute Access

JavaScript is a kind of dynamic language, which means attributes can be added or deleted at runtime, and they?re frequently changed. Most JavaScript engines use a dictionary style structure to store the attributes of an object, so it requires a whole dictionary search to find the position of attributes in memory.It?s quite inefficient and it?s slower than Java and Smalltalk.

To solve this problem, V8 discarded dynamic search and realized it in a different way: Create hidden classes for objects dynamically. In JavaScript, every time when we?re adding a new attribute to an object,we create a subclass with the new attribute from a hidden class as the super class. It?s a recursive course and the above performance happens only once when we first do this. Later we just use the previous hidden subclass when we?re in the same situation. So there?s no need to repeat operation and create a dictionary. This leads to the save of time and energy, as well make it easier for the implementation of class optimization and inner cache [4].

2.3.2. Dynamic Code Generation

When JavaScript is running for the very first time, V8 translate it directly into local machine code, rather than explain it to bytecode. Attribute access is done by inner cache, which is often translated into instructions by V8 at runtime.

When it comes to the code where certain object is accessed, V8 tries to find the current hidden class. Meanwhile, V8 assumes that all objects in the snippet are described by the same hidden class, so V8 willmodify corresponding inner cache to make the direct use of the hidden class more convenient. If thisassumption is correct, the access of attributes can be all done in only 1 instruction. Even if the predictionfails, inner cache is modified again by V8, which won?t take too much time and resource. When one hidden class is shared by a lot of objects, the access speed can be close to most dynamic language access speed. Inner cache and hidden class, mixed with dynamic code and class optimization, improve the efficiency of JavaScript at a large scale [4].

2.3.3. Effective Trash Cleaning

V8 does memory recycles automatically. To guarantee the speed of object distribution, as well cut the time of trash cleaning and clear fragment up, V8 will

interrupt the running application when performing trash cleaning. Mostly, only a small part of object stack is involved in trash cleaning cycle, so the interruption caused little. All location of objects and pointers are logged by V8, so the system won?t take object for pointer and memory overflow is avoided [4].

Besides …the most fluent web browser?, Google collaborated with Adobe and Android 2.2 Froyo fully supports Flash. That?s to say, not only flash media, but all flash web pages can display perfectly on Android. To the contrary, Apple turned down Adobe and take HTML5 as iPhone?s web protocol, making it unable to show some flash based animation.

Android 2.2 Froyo also leads the way in network sharing. Smart phone with Froyo can be connected toa PC as a 3G NIC, and can also conveniently convert 3G signal to Wi-Fi. iOS 4 can do the first too, butfailed to convert 3G to Wi-Fi.

Video conference is both supported by Froyo and iOS 4, but the conditions are different. You can see aFroyo user via camera as long as you get a camera also. However, iOS 4 user can only do video talk toanother iOS 4 user, which is a big limitation.

While Android is ascendant in network interaction, Apple is unique in its friendship and entertainment.The added feature of …software classification? enables user to place sorted softwares into differentdocuments, making it clearer to manage. What?s more, there?re hundreds of thousands applications inApp Store, meaning that iPhone can have up to hundreds of thousands functions. This is a ratherremarkable feature that Apple publicizes.

And the most convincing point given by Apple, is that …Android looks exactly familiar with iPhone.?Although it?s just a subjective sense, the born of iPhone really brought big revolution to the phone industry, and the name …Apple? itself is a world famous brand [7] [8].

3. Open and Closed platforms

3.1. SDK

The most important part of every developing platform is SDK, enable 3rd party developers to make software for the platform. Usually, libraries, debug tools and emulators are included in SDK. Different platforms distribute their SDKs differently. Some SDK is complete free and open, while others are strictly limited.

Developers of open platforms can get and modify part or all of the source code. Google and Linux are leaders of open platforms; they publicized the whole source

code of Android and Linux. The good point is that, platform owners can save a great amount of time and energy developing and maintaining the platform, because 3rd party developers will do this for them. With less money spent on development and maintenance, a relatively low price can attract more and more phone users.

Contrarily, closed platforms lock their source code in the safety and forbid 3rd party accesses. Apple and Microsoft are the representatives of them, they are both closed sourced, but some differences do exists. 3rd party iPhone applications are restricted within narrow limits, for that Apple will look through every application which is uploaded onto …App Store?, and a lot of applications are turned down.Microsoft don?t check Windows applications at all, it all depends on the users themselves. You installed the mareware, you suffer the loss.

3.2. Application Market

Market is the medium between de velopers and users, hence it?s very important. Some predicted that there will be more and more application markets while some don?t think so. In current markets, both do exist. Some specify only one market for their products, while others sell their softwares in various markets.

Softwares from Nokia, Microsoft and Linux Mobile are sold in every market. Developers of these platforms can release their own application in whatever markets, so markets have to compete with each other for a living. This is good for users. However, the lack of universal management may lead to mess and chaos, softwares that have the same functionality exist in different markets, which confuses users a lot.

Correspondingly, sole markets claim that most applications should be sold in them. This kind of monopolization leads to no competitor. …App Store? and ?Android Market? are deputy of sole markets. Normally, iPhone applications can only be found in …App Store?, and Apple will check every one of them by itself. Good news is that every application in …App Store? is officially tested, it?s safe; Bad news is that a lot of pretty good softwares are rejected for various reasons. And a big unofficial mechanism is built by hackers, that is …jailbreak? and …SIM unlock?.

…Jailbreak? is a process that allows iPad, iPhone and iPod Touch users to gain root access and unlock the operating system thus removing any limitations imposed upon them by Apple. Once jailbroken, iPhone users are able to download many extensions and themes previously unavailable through the App Store via installers such as Cydia. A jailbroken iPad, iPhone or iPod Touch is still able to use the App Store and iTunes [9].

And a …SIM lock? is a capability built into GSM phones by mobile phone

manufacturers. Network

providers use this capability to restrict the use of these phones to specific countries and network providers.Generally, phones can be locked to accept only SIM cards based on the International Mobile Subscriber Identity. …SIM unlock? make it possible to use a mobile phone without considering countries and networks specified by mobile phone manufacturers.

However in Android, Google doesn?t test every application at all, so although there?s an official market for Android applications, you can still release your product anywhere you want. Considering security problems, Google banned the use of some components. Like …jailbreak? and …SIM unlock? in iPhone, …root? in Android gives users 100% control of their devices, along with some security risks. …Root? is a process that allows users of cellphones running the Android operating system to attain privileged control (known as "root access") within Android's Linux subsystem, similar to jailbreaking on Apple devices running the iOS operating system, overcoming limitations that the carriers and manufacturers put on such phones. Rooting makes it possible to use custom versions of the Android system such as CyanogenMod, supporting features unavailable in stock ROMs. It also allows for newer versions of Android not supplied by the original device manufacturer. In contrast to iOS jailbreaking, rooting is not needed to run applications not distributed by the official Android Market. It is needed however, when trying to access paid Android applications from countries which are not part of the paid applications market.

3.3. Integration

Some companies focus only on their core industry, i.e. develop an operating system and provide an environment for 3rd party development. Others not only do these, but manage the process of developing a software to publicizing it. Depending on the integration of platforms, we sort them to 4 kinds: full integration platform, market integration platform, device integration platform and no integration platform.

The publicizing model of full integration platform is very strict. Its management ranges from device manufacturing to application release, whose representative is Apple. Apple?s factory produces iPhone,Apple?s …App Store? sells application, Apple?s …iTunes? is the channel of Apple?s resources. The whole process is under Apple?s control.

Market integration platforms commit themselves to developing and selling softwares. Google is one of them. Unlike apple, Google don?t have a factory to

manufacture its own handsets, but only developed Android and set up …Android M arket? for Android applications. However, companies like Google definitely have the capability to produce its own devices. Google is in good relationship with HTC, who is the OEM of T-Mobile, O2 and Orange, etc.

Device integration platforms produce their o wn handsets, but don?t set up application markets. Forexample, RIM makes Blackberry, but there?s no official application market for Blackberry. No integration platforms do few things. Microsoft neither makes mobile phones, nor sets up a market.What they do is only developing the operating system: Windows Phone 7.

4. Conclusion

Representatives of open and closed platforms, Android 2.2 Froyo and iOS 4 are both loved and hated.Great browsers are built into them, and their producers are both world famous revolutionary. Android leans to Internet experience, which comes down in one continuous line with Google. But currently, various versions of Android fill the market, and most companies in Open Handset Alliance tend to customize their own Android systems. These facts make Android lack of a general brand image, so people may feel confused and say …No? to Android. iPhone OS focuses more on entertainment and it?s very friendly. But Apple is too cool to attract more customers: Diehard fans of Steve Jobs buy every product made by Apple, and people who dislike the style Apple do things may just sniffed at Apple.

Besides, Android 2.2 Froyo succeeds the features of open platforms well. It?s a …users only? platform, because users of Froyo can almost customize everything they want. And members of Open Handset

Alliance tend to provide more choices for users. And iOS 4, typically closed platform member, manages everything ranging from OS development to device manufacturing. It?s a …consider for users? platform.To some extent, u sers of Android canonizes …free? and …open?, what they care is if they have 100% management of their handsets, no matter whether the OS is called …Android? or …Another?. Apple users are loyal to the brand; they would like to authorize Apple to make decisions for them. So although some iPhone users love physical keyboards, they bought iPhone. In other words, Android users think a lot of …open platform? rather than the brand Google; most iPhone users are follower of Apple, they love the …closed platforms? cre ated by Steve Jobs.

Both Android and iPhone have their unique IDE, SDK and other characteristics. Believe it or not, no perfection exists in the world, so none of today?s mobile

platforms fully meets the needs of users and researchers. The choice of platform boils down to the needs of users and researchers, this article should make the decision easier. Of course the content of this article is time sensitive; platforms will gradually meet the demands of consumers as new technologies emerging.

References

[1] Dave Mark, Jeff LaMarche. “Beginning iPhone 3 Development: Exploring the iPhone SDK”. 2009.

[2] Erica Sadun. “The iPhone Developer?s Cookbook: Building Application with the iPhone SDK”, 2009.

[3] Ed Burnette. “Hello, Android: Introducing Google?s Mobile De velopment Platform”, 2009.

[4] W.Frank Ableson, Charlie Collins, Robi Sen. “Unlocking Android: A Developer?s Guide”, 2010.

[5] Hee- Yeon Cho, Choon- Sung Nam, Dong- Ryeol Shin. “A Comparison of Open and Closed Mobile Platforms”.

International Conference on Electronics and Information Engineering, 2010.

[6] Ryan C. McKeen, Finis R. Price III. “DROID v iPHONE”. ABA Journal, 2010.

[7] Mies Ginny, Sullivan Mark. “iPhone 4 vs. Droid X: A Head-to-Head Comparison”. PC World, 2010.

[8] Fleishman, Glenn. “More Options With Tomorrow's Cell Phones”. PC World, 2008.

[9] Keller, Mike. “Jailbreaking Your iPhone: The Pros and Cons”. PC World, 2010.

分析和比较开放和封闭的移动平台

摘要

随着Android 2.2 Froyo和iPhone 4版本的发布，开放式和封闭式的移动平台之间的战争愈演愈烈。作为双方代表，Froyo和iOS4在制度的框架，新功能，应用市场和一体化模式有很大的不同。据谷歌和苹果的公司精神，我们做上述各点的一些分析和比较，说明Android的差异，从iPhone浅向更深，然后得出结论开放式和封闭式的移动平台的特点，目的是为移动平台的研究人员提供客观的参考，帮助他们对移动行业有更清晰的认识。当然，Froyo和iOS4都具有自己的优势和劣势，他们距离完美还有很大的距离，依然有进一步改善的空间。

关键词：Android；iPhone；Froyo；OS 4；智能手机；移动平台

1 介绍

近年来，智能手机的普及率不断攀升。越来越多的智能手机被卖出和很多人都更加青睐于它们。智能手机给用户带来了极大方便，并为智能手机研究者创建了机会。这就是说，智能手机的广泛普及，对双方都有利双方。同时，智能手机操作系统发展成为最智能的行业之一。要成为一个智能手机操作系统，该系统应：1.提供服务PC式的服务。2.使用GPU得到更绚丽的视觉效果。 3.允许用户在互联网上自由地冲浪。显然，它们也有一些弱点：1，电池的限制。2。较电脑CPU 来说，手机CPU性能差。 3.存储空间小。 4.在手机电池耗尽时，RAM的使用可能会导致数据丢失。

现在智能手机操作系统的两巨头是Android和iPhone OS。一方面，Android 是基于Linux内核，Dalvik虚拟机，它是开源的。上层的Android是基于Java的，允许开发者使用谷歌SDK开发Android应用程序和在Android 市场销售他们的软件。另一方面，iPhone操作系统基于Unix内核和达尔文模型，但它是封源的，是从Mac OS X继承而来，是iPhone，iPod Touch和iPad默认的操作系统。基于C语言的软件可以在iPhone OS上运行，就像Android，你可以开发自己的iPhone应用程序，并上传到苹果的App Store进行销售。

通过比较Android和iPhone OS的最新系统：Android 2.2 Froyo和iOS4，我们可以了解下开放式和封闭式的智能手机操作系统的主要特点。虽然两个操作系统的整体思路和功能设计有很大的不同，它初略分辨出哪一个更好一点。

2 智能手机

2.1 Android

Android系统的体系结构由5层，从底部到顶部分别是Linux内核，Android 运行库，应用框架和应用程序。Android提供的核心服务，如安全，内存管理，

红外数据通信技术外文翻译文献

红外数据通信技术外文翻译文献(文档含中英文对照即英文原文和中文翻译) Infrared Remote Control System Abstract Red outside data correspondence the technique be currently within the scope of world drive extensive usage of a kind of wireless conjunction technique, drive numerous hardware and software platform support. Red outside the transceiver product have cost low, small scaled turn, the baud rate be quick, point to point SSL, be free from electromagnetism thousand Raos

etc. characteristics, can realization information at dissimilarity of the product fast, convenience, safely exchange and transmission, at short distance wireless deliver aspect to own very obvious of advantage. Along with red outside the data deliver a technique more and more mature, the cost descend, red outside the transceiver necessarily will get at the short distance communication realm more extensive of application. The purpose that design this system is transmit customer’s operation information with infrared rays for transmit media, then demodulate original signal with receive circuit. It use coding chip to modulate signal and use decoding chip to demodulate signal. The coding chip is PT2262 and decoding chip is PT2272. Both chips are made in Taiwan. Main work principle is that we provide to input the information for the PT2262 with coding keyboard. The input information was coded by PT2262 and loading to high frequent load wave whose frequent is 38 kHz, then modulate infrared transmit dioxide and radiate space outside when it attian enough power. The receive circuit receive the signal and demodulate original information. The original signal was decoded by PT2272, so as to drive some circuit to accomplish customer’s operation demand. Keywords: Infrared dray；Code；Decoding；LM386；Red outside transceiver 1 Introduction 1.1 research the background and significance Infrared Data Communication Technology is the world wide use of a wireless connection technology, by the many hardware and software platforms supported. Is a data through electrical pulses and infrared optical pulse switch between the wireless data transceiver technology.

英文文献翻译

中等分辨率制备分离的 快速色谱技术 W. Clark Still,* Michael K a h n , and Abhijit Mitra Departm(7nt o/ Chemistry, Columbia Uniuersity,1Veu York, Neu; York 10027 ReceiLied January 26, 1978 我们希望找到一种简单的吸附色谱技术用于有机化合物的常规净化。这种技术是适于传统的有机物大规模制备分离，该技术需使用长柱色谱法。尽管这种技术得到的效果非常好，但是其需要消耗大量的时间，并且由于频带拖尾经常出现低复原率。当分离的样本剂量大于1或者2g时，这些问题显得更加突出。近年来，几种制备系统已经进行了改进，能将分离时间减少到1-3h，并允许各成分的分辨率ΔR f≥（使用薄层色谱分析进行分析）。在这些方法中，在我们的实验室中，媒介压力色谱法1和短柱色谱法2是最成功的。最近，我们发现一种可以将分离速度大幅度提升的技术，可用于反应产物的常规提纯，我们将这种技术称为急骤色谱法。虽然这种技术的分辨率只是中等（ΔR f≥），而且构建这个系统花费非常低，并且能在10-15min内分离重量在的样本。4 急骤色谱法是以空气压力驱动的混合介质压力以及短柱色谱法为基础，专门针对快速分离，介质压力以及短柱色谱已经进行了优化。优化实验是在一组标准条件5下进行的，优化实验使用苯甲醇作为样本，放在一个20mm*5in.的硅胶柱60内，使用Tracor 970紫外检测器监测圆柱的输出。分辨率通过持续时间（r）和峰宽（w,w/2）的比率进行测定的（Figure 1），结果如图2-4所示，图2-4分别放映分辨率随着硅胶颗粒大小、洗脱液流速和样本大小的变化。

软件开发概念和设计方法大学毕业论文外文文献翻译及原文

毕业设计（论文）外文文献翻译 文献、资料中文题目：软件开发概念和设计方法文献、资料英文题目： 文献、资料来源： 文献、资料发表（出版）日期： 院（部）： 专业： 班级： 姓名： 学号： 指导教师： 翻译日期： 2017.02.14

外文资料原文 Software Development Concepts and Design Methodologies During the 1960s, ma inframes and higher level programming languages were applied to man y problems including human resource s yste ms,reservation s yste ms, and manufacturing s yste ms. Computers and software were seen as the cure all for man y bu siness issues were some times applied blindly. S yste ms sometimes failed to solve the problem for which the y were designed for man y reasons including: ?Inability to sufficiently understand complex problems ?Not sufficiently taking into account end-u ser needs, the organizational environ ment, and performance tradeoffs ?Inability to accurately estimate development time and operational costs ?Lack of framework for consistent and regular customer communications At this time, the concept of structured programming, top-down design, stepwise refinement，and modularity e merged. Structured programming is still the most dominant approach to software engineering and is still evo lving. These failures led to the concept of "software engineering" based upon the idea that an engineering-like discipl ine could be applied to software design and develop ment. Software design is a process where the software designer applies techniques and principles to produce a conceptual model that de scribes and defines a solution to a problem. In the beginning, this des ign process has not been well structured and the model does not alwa ys accurately represent the problem of software development. However,design methodologies have been evolving to accommo date changes in technolog y coupled with our increased understanding of development processes. Whereas early desig n methods addressed specific aspects of the

外文翻译 - 英文

The smart grid Smart grid is the grid intelligent (electric power), also known as the "grid" 2.0, it is based on the integration, high-speed bidirectional communication network, on the basis of through the use of advanced sensor and measuring technology, advanced equipme nt technology, the advanced control method, and the application of advanced technology of decision support system, realize the power grid reliability, security, economic, efficient, environmental friendly and use the security target, its main features include self-healing, incentives and include user, against attacks, provide meet user requirements of power quality in the 21st century, allow all sorts of different power generation in the form of access, start the electric power market and asset optimizatio n run efficiently. The U.S. department of energy (doe) "the Grid of 2030" : a fully automated power transmission network, able to monitor and control each user and power Grid nodes, guarantee from power plants to end users among all the nodes in the whole process of transmission and distribution of information and energy bi-directional flow. China iot alliance between colleges: smart grid is made up of many parts, can be divided into:intelligent substation, intelligent power distribution network, intelli gent watt-hourmeter,intelligent interactive terminals, intelligent scheduling, smart appliances, intelligent building electricity, smart city power grid, smart power generation system, the new type of energy storage system.Now a part of it to do a simple i ntroduction. European technology BBS: an integration of all users connected to the power grid all the behavior of the power transmission network, to provide sustained and effective economic and security of power. Chinese academy of sciences, institute of electrical: smart grid is including all kinds of power generation equipment, power transmission and distribution network, power equipment and storage equipment, on the basis of the physical power grid will be modern advanced sensor measurement technology, network technology, communication

通信工程项目毕业材料外文翻译

用于多跳认知无线电网络的分布式网络编码控制信道 Alfred Asterjadhi等著 1 前言 大多数电磁频谱由政府机构长期指定给公司或机构专门用于区域或国家地区。由于这种资源的静态分配，许可频谱的许多部分在许多时间和/或位置未使用或未被充分利用。另一方面，几种最近的无线技术在诸如IEEE802.11，蓝牙，Zigbee之类的非许可频段中运行，并且在一定程度上对WiMAX进行操作;这些技术已经看到这样的成功和扩散，他们正在访问的频谱- 主要是2.4 GHz ISM频段- 已经过度拥挤。为了为这些现有技术提供更多的频谱资源，并且允许替代和创新技术的潜在开发，最近已经提出允许被许可的设备（称为次要用户）访问那些许可的频谱资源，主要用户未被使用或零星地使用。这种方法通常被称为动态频谱接入（DSA），无线电设备发现和机会性利用未使用或未充分利用的频谱带的能力通常称为认知无线电（CR）技术。 DSA和CR最近都引起了无线通信和网络界的极大关注。通常设想两种主要应用。第一个是认知无线接入（CW A），根据该认知接入点，认知接入点负责识别未使用的许可频谱，并使用它来提供对次用户的接入。第二个应用是我们在这个技术中研究的应用，它是认知自组织网络（CAN），也就是使用 用于二级用户本身之间通信的无许可频谱，用于诸如点对点内容分发，环境监控，安全性等目的，灾难恢复情景通信，军事通信等等。 设计CAN系统比CW A有更多困难，主要有两个原因。第一是识别未使用的频谱。在CW A中，接入点的作用是连接到互联网，因此可以使用简单的策略来推断频谱可用性，例如查询频谱调节器在其地理位置的频谱可用性或直接与主用户协商频谱可用性或一些中间频谱经纪人另一方面，在CAN中，与频谱调节器或主要用户的缺乏直接通信需要二级用户能够使用检测技术自己识别未使用的频谱。第二个困难是辅助用户协调媒体访问目的。在CW A中存在接入点和通常所有二级用户直接与之通信（即，网络是单跳）的事实使得直接使用集中式媒体接入控制（MAC）解决方案，如时分多址（TDMA）或正交频分多址（OFDMA）。相反，预计CAN将跨越多跳，缺少集中控制器;而对于传统的单通道多跳自组织网络而言，这个问题的几个解决方案是已知的，因为假设我们处理允许设备访问的具有成

计算机网络-外文文献-外文翻译-英文文献-新技术的计算机网络

New technique of the computer network Abstract The 21 century is an ages of the information economy, being the computer network technique of representative techniques this ages, will be at very fast speed develop soon in continuously creatively, and will go deep into the people's work, life and study. Therefore, control this technique and then seem to be more to deliver the importance. Now I mainly introduce the new technique of a few networks in actuality live of application. keywords Internet Network System Digital Certificates Grid Storage 1. Foreword Internet turns 36, still a work in progress Thirty-six years after computer scientists at UCLA linked two bulky computers using a 15-foot gray cable, testing a new way for exchanging data over networks, what would ultimately become the Internet remains a work in progress. University researchers are experimenting with ways to increase its capacity and speed. Programmers are trying to imbue Web pages with intelligence. And work is underway to re-engineer the network to reduce Spam (junk mail) and security troubles. All the while threats loom: Critics warn that commercial, legal and political pressures could hinder the types of innovations that made the Internet what it is today. Stephen Crocker and Vinton Cerf were among the graduate students who joined UCLA professor Len Klein rock in an engineering lab on Sept. 2, 1969, as bits of meaningless test data flowed silently between the two computers. By January, three other "nodes" joined the fledgling network.

外文翻译---硬件软件的设计和开发过程知识讲解

附录 一、英文原文 Hardware/Software Design and Development Process Everett Lumpkin and Michael Gabrick Delphi Corporation, Electronics and Safety Division INTRODUCTION Process and technology advancements in the semiconductor industry have helped to revolutionize automotive and consumer electronics. As Moore’s Law predicted, the increase in complexity and operating frequencies of today’s integrated circuits have enabled the creation of system applications once thought to be impossible. And systems such as camera cell phones, automotive infotainment systems, advanced powertrain controllers and handheld personal computers have been realized as a result. In addition to the increases in process technology, the Electronic Design Automation (EDA) industry has helped to transform the way semiconductor integrated circuits (IC) and subsequent software applications are designed and verified. This transformation has occurred in the form of design abstraction, where the implementation continues to be performed at higher levels through the innovation of design automation tools. An example of this trend is the evolution of software development from the early days of machine-level programming to the C++ and Java software written today. The creation of the assembler allowed the programmer to move a level above machine language, which increased the efficiency of code generation and documentation, but still tied the programmer to the underlying hardware architecture. Likewise, the dawn of C / C++ compilers, debuggers and linkers helped to move the abstraction layer further away from the underlying hardware, making the software completely platform independent, easier to read, easier to debug and more efficient to manage. However, a shift to higher levels of software abstraction has not translated to a reduction in complexity or human resources. On the contrary, as integrated systems have become more feature rich, the complexity of the operating system and corresponding applications have increased rapidly, as have the costs associated with the software implementation and verification activities. Certainly the advancements in embedded software tools such as static code checkers, debuggers and hardware emulators have helped to solve some of the software verification problems, but software verification activities have become more time and resource consuming than the actual software creation. Time-to-market constraints have pushed software verification activities to the system-level, and led to a greater demand for production hardware to be made available earlier in

外文翻译computerprogram英文.doc

Computer Program 1 Introduction Computer Program, set of instructions that directs a computer to perform someprocessing function or combination of functions. For the instructions to be carried out, a computer must execute a program, that is, the computer reads the program, and then follow the steps encoded in the program in a precise order until completion. A program can be executed many different times, with each execution yielding a potentially different result depending upon the options and data that the user gives the computer. Programs fall into two major classes: application programs and operating systems. An application program is one that carries out somefunction directly for a user, such as word processing or game-playing. An operating system is a program that manages the computer and the various resources and devices connected to it, such as RAM,hard drives, monitors, keyboards, printers, and modems,so that they maybe used by other programs. Examples of operating systems are DOS, Windows 95, OS\2, and UNIX. 2 Program Development Software designers create new programs by using special applications programs, often called utility programs or development programs. A programmer uses another type of program called a text editor to write the new program in a special notation called a programming language. With the text editor, the programmer creates a text file, which is an ordered list of instructions, also called the program source file. The individual instructions that make up the program source file are called source code. At this point, a special applications program translates the source code into machine language, or object code— a format that the operating system

5G无线通信网络中英文对照外文翻译文献

5G无线通信网络中英文对照外文翻译文献(文档含英文原文和中文翻译)

翻译： 5G无线通信网络的蜂窝结构和关键技术 摘要 第四代无线通信系统已经或者即将在许多国家部署。然而，随着无线移动设备和服务的激增，仍然有一些挑战尤其是4G所不能容纳的，例如像频谱危机和高能量消耗。无线系统设计师们面临着满足新型无线应用对高数据速率和机动性要求的持续性增长的需求，因此他们已经开始研究被期望于2020年后就能部署的第五代无线系统。在这篇文章里面，我们提出一个有内门和外门情景之分的潜在的蜂窝结构，并且讨论了多种可行性关于5G无线通信系统的技术，比如大量的MIMO技术，节能通信，认知的广播网络和可见光通信。面临潜在技术的未知挑战也被讨论了。 介绍 信息通信技术（ICT）创新合理的使用对世界经济的提高变得越来越重要。无线通信网络在全球ICT战略中也许是最挑剔的元素，并且支撑着很多其他的行业，它是世界上成长最快最有活力的行业之一。欧洲移动天文台（EMO）报道2010年移动通信业总计税收1740亿欧元,从而超过了航空航天业和制药业。无线技术的发展大大提高了人们在商业运作和社交功能方面通信和生活的能力无线移动通信的显著成就表现在技术创新的快速步伐。从1991年二代移动通信系统(2G)的初次登场到2001年三代系统（3G）的首次起飞，无线移动网络已经实现了从一个纯粹的技术系统到一个能承载大量多媒体内容网络的转变。4G无线系统被设计出来用来满足IMT-A技术使用IP面向所有服务的需求。在4G系统中，先进的无线接口被用于正交频分复用技术（OFDM），多输入多输出系统（MIMO）和链路自适应技术。4G无线网络可支持数据速率可达1Gb/s的低流度，比如流动局域无线访问，还有速率高达100M/s的高流速，例如像移动访问。LTE系统和它的延伸系统LTE-A，作为实用的4G系统已经在全球于最近期或不久的将来部署。 然而，每年仍然有戏剧性增长数量的用户支持移动宽频带系统。越来越多的

变电站_外文翻译_外文文献_英文文献_变电站的综合概述

英文翻译 A comprehensive overview of substations Along with the economic development and the modern industry developments of quick rising, the design of the power supply system become more and more completely and system. Because the quickly increase electricity of factories, it also increases seriously to the dependable index of the economic condition, power supply in quantity. Therefore they need the higher and more perfect request to the power supply. Whether Design reasonable, not only affect directly the base investment and circulate the expenses with have the metal depletion in colour metal, but also will reflect the dependable in power supply and the safe in many facts. In a word, it is close with the economic performance and the safety of the people. The substation is an importance part of the electric power system, it is consisted of the electric appliances equipments and the Transmission and the Distribution. It obtains the electric power from the electric power system, through its function of transformation and assign, transport and safety. Then transport the power to every place with safe, dependable, and economical. As an important part of power’s transport and control, the transformer substation must change the mode of the traditional design and control, then can adapt to the modern electric power system, the development of modern industry and the of trend of the society life. Electric power industry is one of the foundations of national industry and national economic development to industry, it is a coal, oil, natural gas, hydropower, nuclear power, wind power and other energy conversion into electrical energy of the secondary energy industry, it for the other departments of the national economy fast and stable development of the provision of adequate power, and its level of development is a reflection of the country's economic development an important indicator of the level. As the power in the industry and the importance of the national economy, electricity transmission and distribution of electric energy used in these areas is an indispensable component.。Therefore, power transmission and distribution is critical. Substation is to enable superior power plant power plants or power after adjustments to the lower load of books is an important part of power transmission. Operation of its functions, the capacity of a direct impact on the size of the lower load power, thereby affecting the industrial production and power consumption.Substation system if a link failure, the system will protect the part of action. May result in power outages and so on, to the production and living a great disadvantage. Therefore, the substation in the electric power system for the protection of electricity reliability,

软件开发外文翻译

软件开发外文翻译本页仅作为文档页封面，使用时可以删除 This document is for reference only-rar21year.March

Requirements Phase The chances of a product being developed on time and within budget are somewhat slim unless the members of the software development team agree on what the software product will do. The first step in achieving this unanimity is to analyze the client’s current situation as precisely as possible. For example, it is inadequate to say, “ They need a computer-aided design system because they claim their manual design system, there is lousy. “ Unless the development team knows exactly what is wrong with the current manual system, there is a high probability that aspects of the new computerized system will be equally “lousy. “ Similarly, if a personal computer manufacturer is contemplating development of a new operating system, the first step is to evaluate the firm’s current operating system and analyze carefully exactly why it is unsatisfactory. To take an extreme example, it is vital to know whether the problem exists only in the mind of the sales manager, who blames the operating system for poor sales, or whether users of the operating system are thoroughly disenchanted with its functionality and reliability. Only after a clear picture of the present situation has been gained can the team attempt to answer the critical question, What must the new product be able to do The process of answering this question is carried out during the requirements phase. A commonly held misconception is that , during the requirements phase, the developers must determine what software the client wants. On the contrary, the real objective of the requirements phase is to determine what software the client needs. The problem is that many clients do not know what they need. Furthermore, even a client who has a good idea of what is needed may have difficulty in accurately conveying these ideas to the developers, because most clients are less computer literate than the members of the development team.