上下文無關文法(Context-Free Grammar, CFG)是一個4元組G=(V, T, S, P),其中,V和T是不相交的有限集,S∈V,P是一組有限的產生式規則集,形如A→α,其中A∈V,且α∈(V∪T)*。V的元素稱為非終結符,T的元素稱為終結符,S是一個特殊的非終結符,稱為文法開始符。 設G=(V, T, S, P)是一個CFG,則G產生的語言是所有可由G產生的字符串組成的集合,即L(G)={x∈T* | Sx}。一個語言L是上下文無關語言(Context-Free Language, CFL),當且僅當存在一個CFG G,使得L=L(G)。 *⇒ 例如,設文法G:S→AB A→aA|a B→bB|b 則L(G)={a^nb^m | n,m>=1} 其中非終結符都是大寫字母,開始符都是S,終結符都是小寫字母。
標簽: Context-Free Grammar CFG
上傳時間: 2013-12-10
上傳用戶:gaojiao1999
《Prolog Programming in Depth》: In this book, we emphasize practical Prolog programming, not just theory. We present several ready-to-run expert system shells, as well as routines for sorting,searching, natural language processing, and even numerical equation solving. We also emphasize interoperability with other software. For example, Chapter 5 presents techniques for reading Lotus spreadsheets and other special file formats from within a Prolog program.
標簽: Prolog Programming programming emphasize
上傳時間: 2014-01-24
上傳用戶:JIUSHICHEN
Writing Your First ASP Application ( Quick Start ) (Page 1 of 8 ) There are many tutorials out there that show you how to program in ASP. Some of them are good, and some are bad. Some of them are downright terrible. In any case, you ve read a bit about ASP and now you are ready to build your first application. But where do you start? In my own experience, I have found that I find it easier to learn something if I actually work with it hands-on. Just reading a book or documentation doesn’t give you the practical knowledge you need to be able to rush off and start creating applications. In this article, I will discuss the creation of a very simple application. I will cover what the application will do, how we will approach writing it, demonstrate in code how we will do it, and discuss additional features that could be added to it. Writing Your First ASP Application ( Quick Start ) - Users On Your Website
標簽: Application tutorials Writing First
上傳時間: 2015-11-05
上傳用戶:franktu
一:需求分析 1. 問題描述 魔王總是使用自己的一種非常精練而抽象的語言講話,沒人能聽懂,但他的語言是可逐步解釋成人能聽懂的語言,因為他的語言是由以下兩種形式的規則由人的語言逐步抽象上去的: ----------------------------------------------------------- (1) a---> (B1)(B2)....(Bm) (2)[(op1)(p2)...(pn)]---->[o(pn)][o(p(n-1))].....[o(p1)o] ----------------------------------------------------------- 在這兩種形式中,從左到右均表示解釋.試寫一個魔王語言的解釋系統,把 他的話解釋成人能聽得懂的話. 2. 基本要求: 用下述兩條具體規則和上述規則形式(2)實現.設大寫字母表示魔王語言的詞匯 小寫字母表示人的語言的詞匯 希臘字母表示可以用大寫字母或小寫字母代換的變量.魔王語言可含人的詞匯. (1) B --> tAdA (2) A --> sae 3. 測試數據: B(ehnxgz)B 解釋成 tsaedsaeezegexenehetsaedsae若將小寫字母與漢字建立下表所示的對應關系,則魔王說的話是:"天上一只鵝地上一只鵝鵝追鵝趕鵝下鵝蛋鵝恨鵝天上一只鵝地上一只鵝". | t | d | s | a | e | z | g | x | n | h | | 天 | 地 | 上 | 一只| 鵝 | 追 | 趕 | 下 | 蛋 | 恨 |
上傳時間: 2014-12-02
上傳用戶:jkhjkh1982
Space-Time Processing for CDMA Mobile Communications.Written for research students and design engineers, this book addresses many basic questions related to the use of space-time processing in CDMA-based third-generation systems
標簽: Communications Space-Time Processing for
上傳時間: 2014-01-13
上傳用戶:cooran
漢諾塔!!! Simulate the movement of the Towers of Hanoi puzzle Bonus is possible for using animation eg. if n = 2 A→B A→C B→C if n = 3 A→C A→B C→B A→C B→A B→C A→C
標簽: the animation Simulate movement
上傳時間: 2017-02-11
上傳用戶:waizhang
Have you ever seen players eyes light up as they explore the worlds that you ve created in your games? If you have, then game development probably has you hooked firmly in its grasp! If you ve never taken your games beyond the PC, now s the time! "J2ME Game Programming" is a hands-on guide that teaches you how to create games for micro-devices. You ll be amazed at just how cool the games you create can look and play. Focusing primarily on mobile phone game creation, you ll jump right in and create your own games as you work your way through the book. The thought has surely crossed your mind that it would be nice to make some money off of this cool hobby of yours. J2ME offers real opportunity to profit from your games. Learn how you can earn revenue from your games by taking them to market. If you have a basic understanding of Java, then you re ready to explore all that "J2ME Game Programming" has to offer!
標簽: you created players explore
上傳時間: 2017-02-25
上傳用戶:lanhuaying
ASP .NET 3.5 C# 2008 this a advance version of .net framework. So reading this book you will be ready to develop web application in VS2008
標簽: this framework advance reading
上傳時間: 2017-03-22
上傳用戶:a673761058
將魔王的語言抽象為人類的語言:魔王語言由以下兩種規則由人的語言逐步抽象上去的:α-〉β1β2β3…βm ;θδ1δ2…-〉θδnθδn-1…θδ1 設大寫字母表示魔王的語言,小寫字母表示人的語言B-〉tAdA,A-〉sae,eg:B(ehnxgz)B解釋為tsaedsaeezegexenehetsaedsae對應的話是:“天上一只鵝地上一只鵝鵝追鵝趕鵝下鵝蛋鵝恨鵝天上一只鵝地上一只鵝”。(t-天d-地s-上a-一只e-鵝z-追g-趕x-下n-蛋h-恨)
上傳時間: 2013-12-19
上傳用戶:aix008
本代碼為編碼開關代碼,編碼開關也就是數字音響中的 360度旋轉的數字音量以及顯示器上用的(單鍵飛梭開 關)等類似鼠標滾輪的手動計數輸入設備。 我使用的編碼開關為5個引腳的,其中2個引腳為按下 轉輪開關(也就相當于鼠標中鍵)。另外3個引腳用來 檢測旋轉方向以及旋轉步數的檢測端。引腳分別為a,b,c b接地a,c分別接到P2.0和P2.1口并分別接兩個10K上拉 電阻,并且a,c需要分別對地接一個104的電容,否則 因為編碼開關的觸點抖動會引起輕微誤動作。本程序不 使用定時器,不占用中斷,不使用延時代碼,并對每個 細分步數進行判斷,避免一切誤動作,性能超級穩定。 我使用的編碼器是APLS的EC11B可以參照附件的時序圖 編碼器控制流水燈最能說明問題,下面是以一段流水 燈來演示。
上傳時間: 2017-07-03
上傳用戶:gaojiao1999