上下文无关文法（Context-Free Grammar, CFG）是一个4元组G=(V, T, S, P)，其中，V和T是不相交的有限集，S∈V，P是一组有限的产生式规则集，形如A→α，其中A∈V，且α∈(V∪T)*。V的元素称为非终结符，T的元素称为终结符，S是一个特殊的非终结符，称为文法开始符。 设G=(V, T, S, P)是一个CFG，则G产生的语言是所有可由G产生的字符串组成的集合，即L(G)={x∈T* | Sx}。一个语言L是上下文无关语言（Context-Free Language, CFL），当且仅当存在一个CFG G，使得L=L(G)。 *⇒ 例如，设文法G：S→AB A→aA|a B→bB|b 则L(G)={a^nb^m | n,m>=1} 其中非终结符都是大写字母，开始符都是S，终结符都是小写字母。
标签： Context-Free Grammar CFG
上传时间： 2013-12-10
上传用户：gaojiao1999
This lab exercise will introduce you to the AccelWare IP generators. AccelWare is a library of over fifty IP generators, available in the form of three toolkits that produce synthesizable MATLAB for common MATLAB built in and toolbox functions. Each generator offers macro and micro-architecture selections that allow full customization of the generated model to the target application requirements.
标签： AccelWare generators introduce exercise
上传时间： 2013-12-16
上传用户：2467478207
Given an positive integer A (1 <= A <= 109), output the lowest bit of A. For example, given A = 26, we can write A in binary form as 11010, so the lowest bit of A is 10, so the output should be 2. Another example goes like this: given A = 88, we can write A in binary form as 1011000, so the lowest bit of A is 1000, so the output should be 8.
标签： A. positive integer example
上传时间： 2014-01-22
上传用户：rocketrevenge
一:需求分析 1. 问题描述 魔王总是使用自己的一种非常精练而抽象的语言讲话,没人能听懂,但他的语言是可逐步解释成人能听懂的语言,因为他的语言是由以下两种形式的规则由人的语言逐步抽象上去的: ----------------------------------------------------------- (1) a---> (B1)(B2)....(Bm) (2)[(op1)(p2)...(pn)]---->[o(pn)][o(p(n-1))].....[o(p1)o] ----------------------------------------------------------- 在这两种形式中,从左到右均表示解释.试写一个魔王语言的解释系统,把 他的话解释成人能听得懂的话. 2. 基本要求: 用下述两条具体规则和上述规则形式(2)实现.设大写字母表示魔王语言的词汇 小写字母表示人的语言的词汇 希腊字母表示可以用大写字母或小写字母代换的变量.魔王语言可含人的词汇. (1) B --> tAdA (2) A --> sae 3. 测试数据: B(ehnxgz)B 解释成 tsaedsaeezegexenehetsaedsae若将小写字母与汉字建立下表所示的对应关系,则魔王说的话是:"天上一只鹅地上一只鹅鹅追鹅赶鹅下鹅蛋鹅恨鹅天上一只鹅地上一只鹅". | t | d | s | a | e | z | g | x | n | h | | 天 | 地 | 上 | 一只| 鹅 | 追 | 赶 | 下 | 蛋 | 恨 |
上传时间： 2014-12-02
上传用户：jkhjkh1982
This paper examines the asymptotic (large sample) performance of a family of non-data aided feedforward (NDA FF) nonlinear least-squares (NLS) type carrier frequency estimators for burst-mode phase shift keying (PSK) modulations transmitted through AWGN and flat Ricean-fading channels. The asymptotic performance of these estimators is established in closed-form expression and compared with the modified Cram`er-Rao bound (MCRB). A best linear unbiased estimator (BLUE), which exhibits the lowest asymptotic variance within the family of NDA FF NLS-type estimators, is also proposed.
标签： performance asymptotic examines non-data
上传时间： 2015-12-30
上传用户：225588
We have a group of N items (represented by integers from 1 to N), and we know that there is some total order defined for these items. You may assume that no two elements will be equal (for all a, b: a<b or b<a). However, it is expensive to compare two items. Your task is to make a number of comparisons, and then output the sorted order. The cost of determining if a < b is given by the bth integer of element a of costs (space delimited), which is the same as the ath integer of element b. Naturally, you will be judged on the total cost of the comparisons you make before outputting the sorted order. If your order is incorrect, you will receive a 0. Otherwise, your score will be opt/cost, where opt is the best cost anyone has achieved and cost is the total cost of the comparisons you make (so your score for a test case will be between 0 and 1). Your score for the problem will simply be the sum of your scores for the individual test cases.
标签： represented integers group items
上传时间： 2016-01-17
上传用户：jeffery
The XML Toolbox converts MATLAB data types (such as double, char, struct, complex, sparse, logical) of any level of nesting to XML format and vice versa. For example, >> project.name = MyProject >> project.id = 1234 >> project.param.a = 3.1415 >> project.param.b = 42 becomes with str=xml_format(project, off ) "<project> <name>MyProject</name> <id>1234</id> <param> <a>3.1415</a> <b>42</b> </param> </project>" On the other hand, if an XML string XStr is given, this can be converted easily to a MATLAB data type or structure V with the command V=xml_parse(XStr).
标签： converts Toolbox complex logical
上传时间： 2016-02-12
上传用户：a673761058
Hospital queue is a regular met are very familiar with the phenomenon. It every day one way or another in the form in front of us. For example, patients to hospitals, pharmacies dispensing to patients, patients with transfusion to the infusion room, often need wait To some kind of service.
标签： phenomenon Hospital familiar regular
上传时间： 2013-12-26
上传用户：四只眼
The purpose of this Primer is to help you begin to use MATLAB. It is not intended to be a substitute for the online help facility or the MATLAB documentation (such as Getting Started with MATLAB, available in printed form and online). The Primer can best be used hands-on. You are encouraged to work at the computer as you read the Primer and freely experiment with the examples. This Primer, along with the online help facility, usually suffices for students in a class requiring the use of MATLAB.
标签： intended substitu to purpose
上传时间： 2013-12-27
上传用户：dengzb84
文件说明java模式，The CustomerFacade class offers a higher level business service in the form of the saveCustomerData method. Instead of interacting with each of the subsystem components directly, the client AccountManager can make use of the higher level, more simplified interface offered by the CustomerFacade object to validate and save the input customer data.
上传时间： 2016-12-10
上传用户：kernaling
