我们编写的程序由两个主要方面组成 1 算法的集合就是将指令组织成程序来解决某个特定的问题 2 数据的集合算法在这些数据上操作以提供问题的解决方案 纵观短暂的计算机发展史这两个主要方面算法和数据一直保持不变发展演化的 是它们之间的关系就是所谓的程序设计方法programming paradigm 在过程化程序设计方法procedural programming 中一个问题可直接由一组算法来建 立模型例如公共图书馆的资料借阅/登记check out/check in 系统是由一系列过程表现 出来的其中两个主要的过程是资料的借阅和登记这些数据被独立存储起来我们既可以 在某个全局位置上访问这些数据或者把数据传递给过程以便它能够访问这些数据Fortran C 和 Pascal 是三种著名的过程语言C++也支持过程化程序设计单独的过程如check_in() check_out() over_due() fine()等等都被称为函数第三篇将集中讨论C++对过程化程序 设计方法的支持尤其将重点讨论函数函数模板和通用算法 在20 世纪70 年代程序设计的焦点从过程化程序设计方法转移到了抽象数据类型 abstract data type 简写为ADT 的程序设计上现在通常称之为基于对象(object based 的程序设计在基于对象的程序设计方法中我们通过一组数据抽象来建立问题的模型在 C++中我们把这些抽象称为类class 例如在这种方法下图书馆资料借阅登记系统就 由类的对象实例比如书借阅者还书时间罚款等之间的相互作用表现出来以此表 示出图书馆的抽象概念与每个类相关的算法被称为该类的公有接口public interface 数 据以私有形式被存储在每个对象中对数据的访问应与一般的程序代码隔离开来CLU Ada 和Modula-2 是三种支持抽象数据类型的程序设计语言第四篇将说明和讨论C++对抽象数据 类型程序设计方法的支持 面向对象的程序设计方法通过继承inheritance 机制和动态绑定dynamic binding 机 制扩展了抽象数据类型继承机制是对现有实现代码的重用动态绑定是指对现有的公有接 口的重用以前独立的类型现在有了类型/子类型的特定关系一本书一盒录像带一段录 音甚至孩子的宠物尽管它们有各自的借阅/登记方式但都可以成为图书馆的收藏资料 共享的公有接口和私有的数据都放在一个抽象类图书馆资料LibraryMaterial 中每个特 殊的图书馆资料类都从LibraryMaterial 抽象类继承共享的行为它们只需要提供与自身行为相 关的算法和数据Simula Smalltalk 和Java 是三种支持面向对象程序设计方法的著名语言 第五篇将集中讨论C++对面向对象程序设计方法的支持 C++是一种支持多种程序设计方法的语言虽然我们主要把它当作面向对象的语言但 实际上它也提供对过程化的和基于对象的程序设计方法的支持这样做的好处是对每个问题 都能够提供最合适的解决方案事实上没有一种程序设计方法能够
上传时间： 2019-01-30
上传用户：jizhi111
无线电CW通联 基本Q短语，通联实例 A: CQCQCQ DE BA4ALC/5 BA4ALC/5 BA4ALC/5 PSE K B:BA4ALC/5 DE BD4IZL BD4IZL K A:BD4IZL DE BA4ALC/5 GM TNX FER CALL DR OM UR RST 559 55N K B:RR BA4ALC/5 DE BD4IZL GM DR OM TNX 55N RPRT UR 599 5NN FB MY NAME IS YU YU QTH JINAN JINAN BA4ALC/5 DE BD4IZL K A: DR YU OM TNX FB RPRT OP JACK JACK QTH NINGBO NINGBO WX HR IS FINE ES WARM TEMP 20C 20C HW? DE BA4ALC/5 K B:R DR JACK OM WX CLOUDY CLOUDY ES TEMP 15C 15C BT RIG FT80C FT80C ANT DIPOLE DP PWR 100WATTS 1TTW BA4ALC/5 DE BD4IZL K A: BD4IZL DE BA4ALC/5 MY RIG IS IC746PRO IC746PRO ES PWR 100W 1OOW BT ANT 2 ELE YAGI 2ELE YAGI 12MH TNX FER NICE QSO QSL VIA BURO HPE CUAGN BD4IZL DE BA4ALC/5 73 73 GL ES GB TU TU SK.. B:TNX FB CW QSO QSL QRZ.COM CUAGN BA4ALC/5 DE BD4IZL 73 DR JACK TU SK.. A:. B:.
上传时间： 2019-03-05
上传用户：shuyinglee
Mobile communication has gained significant importance in today’s society. As of 2010, the number of mobile phone subscribers has surpassed 5 billion [ABI10], and the global annual mobile revenue is soon expected to top $1 trillion [Inf10]. While these numbers appear promising for mobile operators at first sight, the major game-changer that has come up recently is the fact that the market is more and more driven by the demand for mobile data traffic [Cis10].
上传时间： 2020-05-27
上传用户：shancjb
With the advancement of technology and miniaturization of electronic devices, applications of wireless sensor networks (WSNs) can be seen in diverse areas in our lives. In fact, these WSNs have gained a lot of attention from both the research community and industry, making them easily available on the market. An extensive amount of research, easy availability, and cheap cost make them useful in various types of futuristic applications as well.
标签： Communication Technologies Emerging
上传时间： 2020-05-27
上传用户：shancjb
This book describes how global mobile communication was made. It is written for those who want or need to know how this was achieved e.g.: † Young professionals who want to build their career on GSM and UMTS and need to understand the basics † Strategic and technical planners who want to drive the future GSM and UMTS develop- ment † Strategists who plan to repeat GSM’s success in the fourth generation † Academics, who want to understand and analyse the development of GSM and UMTS; † Activists in other large scale international communication projects who want to use experiences gained
标签： Creation UMTS GSM and The of
上传时间： 2020-05-27
上传用户：shancjb
Having dealt with in-depth analysis of SS#7, GSM and GPRS networks I started to monitor UTRAN interfaces approximately four years ago. Monitoring interfaces means decoding the data captured on the links and analysing how the different data segments and messages are related to each other. In general I wanted to trace all messages belonging to a single call to prove if the network elements and protocol entities involved worked fine or if there had been failures or if any kind of suspicious events had influenced the normal call proceeding or the call’s quality of service. Cases showing normal network behaviour have been documented in Kreher and Ruedebusch (UMTS Signaling. John Wiley & Sons, Ltd, 2005), which provides examples for technical experts investigating call flows and network procedures.
标签： Performance Measurement Practical Guide UMTS
上传时间： 2020-06-01
上传用户：shancjb
One of the predominant topics in the domain of the emerging Smart Grid can be seen in standardization. With the combination of existing protection and automa- tion technology with upcoming ICT-based solutions, different interoperability is- sues arise when technologies have to be combined in the infrastructure. Standards have proven to be one of the most striking solutions to actually cope with this topic. Since 2008, this topic has gained much attention in various political and technical agendas.
标签： Standardization Smart Grids in
上传时间： 2020-06-07
上传用户：shancjb
Radio frequency identification (RFID) is a type of automatic identification systems which has gained popularity in recent years for being fast and reliable in keeping track of the individual objects. In RFID systems, contactless object identification is achieved using radio signals without the need for physical contact as the case with other existing identification technologies such as barcodes. Therefore, a huge number of items can be identified in a short amount of time with high reliability and low cost which makes the RFID technology very attractive for a wide range of applications such as supply chain management, e-health, monitoring humans, pets, animals, and many other objects, toll control, and electrical tagging. Furthermore, RFID technology eliminates the human error and reduces the total cost of the products.
上传时间： 2020-06-08
上传用户：shancjb
Research on microwave power amplififiers has gained a growing importance demanded by the many continuously developing applications which require such subsystem performance. A broad set of commercial and strategic systems in fact have their overall performance boosted by the power amplififier, the latter becoming an enabling component wherever its effificiency and output power actually allows functionalities and operating modes previously not possible. This is the case for the many wireless systems and battery-operated systems that form the substrate of everyday life, but also of high-performance satellite and dual-use systems.
上传时间： 2021-10-30
上传用户：得之我幸78
It all started rather innocuously. I walked into Dr GT Murthy’s office one fine day, andchanged my life. “Doc” was then the General Manager, Central R&D, of a very largeelectrical company headquartered in Bombay. In his new state-of-the-art electronics center,he had hand-picked some of India’s best engineers (over a hundred already) ever assembledunder one roof. Luckily, he too was originally a Physicist, and that certainly helped me gainsome empathy. Nowadays he is in retirement, but I will always remember him as athoroughly fair, honest and facts-oriented person, who led by example. There were severalthings I absorbed from him that are very much part of my basic engineering persona today.You can certainly look upon this book as an extension of what Doc started many years agoin India … because that’s what it really is! I certainly wouldn’t be here today if I hadn’t metDoc. And in fact, several of the brash, high-flying managers I’ve met in recent years,desperately need some sort of crash course in technology and human values from Doc!
标签： 开关电源
上传时间： 2021-11-23
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