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Description: he power method will be applied to the jacobian matrix of the
2-D henon map to approximate the first Lyapunov exponent by creating
a graph of ln|yn| vs. n, where n is the number of iterations of the
power method and yn = 1/n*ln|DG^n(xo)*yo|. The slope will be an
approximation to the largest Lyapunov exponent.-he power method will be applied to the jacob ian matrix of the 2-D map to approximate henon th e first Lyapunov exponent by creating a graph of ln | yn | vs. n, where n is the number of iterations of the power m ethod and yn = a / n * ln | DG ^ n (xo) * yo |. The slope w ill be an approximation to the largest Lyapunov exponent.
Platform: |
Size: 1428 |
Author: 杨蒙 |
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Description: Some algorithms of variable step size LMS adaptive filtering are studied．The VS—LMS algorithm is improved．
Another new non-linear function between肛and e(／ t)is established．The theoretic analysis and computer
simulation results show that this algorithm converges more quickly than the origina1．Furthermore，better antinoise
property is exhibited under Low—SNR environment than the original one．-variable step size of a LMS daptive filtering are studied. The VS-LMS algorithm is improved. Another new non-linear function between anus and e (/ t) is established. The theoretic analysis and computer simulatio n results show that this algorithm converges mo 're quickly than the origina1. Furthermore, better antinoise property is exhibited under L ow - SNR environment than the original one.
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Size: 3701 |
Author: 上将 |
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Description: 一系列缓冲区类支撑起了 Java 2 平台标准版的新 I/O（NIO）包。这些类的数据容器形成了其它 NIO 操作（如套接字通道上的非阻塞读取）的基础。在本月的 Merlin 的魔力中，常驻 Java 编程专家 John Zukowski 展示了如何操作那些数据缓冲区来执行如读／写原语这样的任务以及如何使用内存映射文件。在以后的文章里，他将把这里所提到的概念扩展到套接字通道的使用。 Java 2 平台标准版（Java 2 Platform Standard Edition，J2SE）1.4 对 Java 平台的 I/O 处理能力做了大量更改。它不仅用流到流的链接方式继续支持以前 J2SE 发行版的基于流的 I/O 操作，而且 Merlin 还添加了新的功能 — 称之为新 I/O 类（NIO），现在这些类位于 java.nio 包中。
I/O 执行输入和输出操作，将数据从文件或系统控制台等传送至或传送出应用程序。（有关 Java I/O 的其它信息，请参阅 参考资料）。
缓冲区基础
抽象的 Buffer 类是 java.nio 包支持缓冲区的基础。 Buffer的工作方式就象内存中用于读写基本数据类型的 RandomAccessFile 。象 RandomAccessFile一样，使用 Buffer ，所执行的下一个操作（读／写）在当前某个位置发生。执行这两个操作中的任一个都会改变那个位置，所以在写操作之后进行读操作不会读到刚才所写的内容，而会读到刚才所写内容之后的数据。 Buffer 提供了四个指示方法，用于访问线性结构（从最高值到最低值）：
"capacity() ：表明缓冲区的大小
"limit() ：告诉您到目前为止已经往缓冲区填了多少字节，或者让您用 :limit(int newLimit) 来改变这个限制
"position() ：告诉您当前的位置，以执行下一个读／写操作
"mark() ：为了稍后用 reset() 进行重新设置而记住某个位置
缓冲区的基本操作是 get() 和 put() ；然而，这些方法在子类中都是针对每种数据类型的特定方法。为了说明这一情况，让我们研究一个简单示例，该示例演示了从同一个缓冲区读和写一个字符。在清单 1 中， flip() 方法交换限制和位置，然后将位置置为 0，并废弃标记，让您读刚才所写的数据：
清单 1. 读／写示例
import java.nio.*;
...
CharBuffer buff = ...;
buff.put('A');
buff.flip();
char c = buff.get();
System.out.println("An A: " + c);
现在让我们研究一些具体的 Buffer 子类。
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缓冲区类型
Merlin 具有 7 种特定的 Buffer 类型，每种类型对应着一个基本数据类型（不包括 boolean）：
"ByteBuffer
"CharBuffer
"DoubleBuffer
"FloatBuffer
"IntBuffer
"LongBuffer
"ShortBuffer
在本文后面，我将讨论第 8 种类型 MappedByteBuffer ，它用于内存映射文件。如果您必须使用的类型不是这些基本类型，则可以先从 ByteBuffer 获得字节类型，然后将其转换成 Object 或其它任何类型。
正如前面所提到的，每个缓冲区包含 get() 和 put() 方法，它们可以提供类型安全的版本。通常，需要重载这些 get() 和 put() 方法。例如，有了 CharBuffer ，可以用 get() 获得下一个字符，用 get(int index) 获得某个特定位置的字符，或者用 get(char[] destination) 获得一串字符。静态方法也可以创建缓冲区，因为不存在构造函数。那么，仍以 CharBuffer为例，用 CharBuffer.wrap(aString) 可以将 String对象转换成 CharBuffer 。为了演示，清单 2 接受第一个命令行参数，将它转换成 CharBuffer ，并显示参数中的每个字符：
清单 2. CharBuffer 演示
import java.nio.*;
public class ReadBuff {
public static void main(String args[]) {
if (args.length != 0) {
CharBuffer buff = CharBuffer.wrap(args[0]);
for (int i=0, n=buff.length(); i<n; i++) {
System.out.println(i + " : " + buff.get());
}
}
}
}
请注意，这里我使用了 get() ，而没有使用 get(index) 。我这样做的原因是，在每次执行 get() 操作之后，位置都会移动，所以不需要手工来声明要检索的位置。
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直接 vs. 间接
既然已经了解了典型的缓冲区，那么让我们研究直接缓冲区与间接缓冲区之间的差别。在创建缓冲区时，可以要求创建直接缓冲区，创建直接缓冲区的成本要比创建间接缓冲区高，但这可以使运行时环境直接在该缓冲区上进行较快的本机 I/O 操作。因为创建直接缓冲区所增加的成本，所以直接缓冲区只用于长生存期的缓冲区，而不用于短生存期、一次性且用完就丢弃的缓冲区。而且，只能在 ByteBuffer 这个级别上创建直接缓冲区，如果希望使用其它类型，则必须将 Buffer 转换成更具体的类型。为了演示，清单 3 中代码的行为与清单 2 的行为一样，但清单 3 使用直接缓冲区：
清单 3. 列出网络接口
import java.nio.*;
public class ReadDirectBuff {
public static void main(String args[]) {
if (args.length != 0) {
String arg = args[0];
int size = arg.length();
ByteBuffer byteBuffer = ByteBuffer.allocateDirect(size*2);
CharBuffer buff = byteBuffer.asCharBuffer();
buff.put(arg);
buff.rewind();
for (int i=0, n=buff.length(); i<n; i++) {
System.out.println(i + " : " + buff.get());
}
}
}
}
在上面的代码中，请注意，不能只是将 String 包装在直接 ByteBuffer中。必须首先创建一个缓冲区，先填充它，然后将位置倒回起始点，这样才能从头读。还要记住，字符长度是字节长度的两倍，因此示例中会有 size*2 。
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内存映射文件
第 8 种 Buffer 类型 MappedByteBuffer 只是一种特殊的 ByteBuffer 。 MappedByteBuffer 将文件所在区域直接映射到内存。通常，该区域包含整个文件，但也可以只映射部分文件。所以，必须指定要映射文件的哪部分。而且，与其它 Buffer 对象一样，这里没有构造函数；必须让 java.nio.channels.FileChannel的 map() 方法来获取 MappedByteBuffer 。此外，无需过多涉及通道就可以用 getChannel() 方法从 FileInputStream 或 FileOutputStream获取 FileChannel 。通过从命令行传入文件名来读取文本文件的内容，清单 4 显示了 MappedByteBuffer ：
清单 4. 读取内存映射文本文件
import java.io.*;
import java.nio.*;
import java.nio.channels.*;
import java.nio.charset.*;
public class ReadFileBuff {
public static void main(String args[]) throws IOException {
if (args.length != 0) {
String filename = args[0];
FileInputStream fis = new FileInputStream(filename);
FileChannel channel = fis.getChannel();
int length = (int)channel.size();
MappedByteBuffer byteBuffer =
channel.map(FileChannel.MapMode.READ_ONLY, 0, length);
Charset charset = Charset.forName("ISO-8859-1");
CharsetDecoder decoder = charset.newDecoder();
CharBuffer charBuffer = decoder.decode(byteBuffer);
for (int i=0, n=charBuffer.length(); i<n; i++) {
System.out.print(charBuffer.get());
}
}
}
}
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Size: 5876 |
Author: 635868631@qq.com |
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Description: 大量C++.NET和VB.NET源码-A large number of C++. NET and VB.NET source code
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Size: 34464768 |
Author: 站长 |
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Description: he power method will be applied to the jacobian matrix of the
2-D henon map to approximate the first Lyapunov exponent by creating
a graph of ln|yn| vs. n, where n is the number of iterations of the
power method and yn = 1/n*ln|DG^n(xo)*yo|. The slope will be an
approximation to the largest Lyapunov exponent.-he power method will be applied to the jacob ian matrix of the 2-D map to approximate henon th e first Lyapunov exponent by creating a graph of ln | yn | vs. n, where n is the number of iterations of the power m ethod and yn = a/n* ln | DG ^ n (xo)* yo |. The slope w ill be an approximation to the largest Lyapunov exponent.
Platform: |
Size: 1024 |
Author: 杨蒙 |
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Description: Some algorithms of variable step size LMS adaptive filtering are studied．The VS—LMS algorithm is improved．
Another new non-linear function between肛and e(／ t)is established．The theoretic analysis and computer
simulation results show that this algorithm converges more quickly than the origina1．Furthermore，better antinoise
property is exhibited under Low—SNR environment than the original one．-variable step size of a LMS daptive filtering are studied. The VS-LMS algorithm is improved. Another new non-linear function between anus and e (/ t) is established. The theoretic analysis and computer simulatio n results show that this algorithm converges mo 're quickly than the origina1. Furthermore, better antinoise property is exhibited under L ow- SNR environment than the original one.
Platform: |
Size: 3072 |
Author: 上将 |
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Description: The early parser is like a dynamic programming. The reasonable time vs sentence length should be O(n^2) n=input length. But I don’t know why the execution time are all very short to be examinated.-The early parser is like a dynamic programming. The reasonable time vs sentence length should be O (n ^ 2) n = input length. But I don t know why the execution time are all very short to be examinated.
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Size: 43008 |
Author: 詹包 |
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Description: Used to plot temp VS time graph
But has no data attached n the x axis(time) has time string format
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Size: 1024 |
Author: Rakesh/Lohit |
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Description: MIMO 系统仿真，对时变信道的自适应调制-erq.m : function for ERQ algorithm in MIMO systems
space_wf.m : function for spatial domain power waterfilling
st_wf.m : function for spatial and temporal domain waterfilling
MIMO_rate.m : Plot spectral efficiency vs SNR for various cases
MIMO_ber.m : Plot BER vs SNR for ERQ algorithm
Report_figN.m : Plot figure N in final report (N=1,2,...,8)
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Size: 18432 |
Author: jonathan Peng |
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Description: 分布文件系统
Ceph是基于California大学存储系统研究中心研究成果的LGPL项目-v0.13 released
We’ve made a v0.13 release. This mostly fixes bugs with v0.12 that have come up over the past couple weeks:
* [ku]lcient: fix sync read vs eof, lseek(…, SEEK_END)
* mds: misc bug fixes for multiclient file access
But also a few other big things:
* osd: stay active during backlog generation
* osdmap: override mappings (pg_temp)
* kclient: some improvements in kmalloc, memory preallocation
The OSD changes mean that the storage cluster can temporarily delegate authority for a placement group to the node that has the complete data while an index is being generated for recovery (that can take a while). Once that’s ready, control will fall back to the new/correct node and the usual recovery will kick in.
The disk format and wire protocols have changed with this version.
We’re continuing to work on the security infrastructure… hopefully will be ready for v0.14.
Here are the relevant URLs:
* Git tree at git://ceph.newdream.n
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Size: 4090880 |
Author: whoami |
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Description: Capacity of a MIMO System vs. C/N Relatioship
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Size: 2048 |
Author: dcoloma |
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Description: This MATLAB code plot the aperture efficiency Vs the subtended angle. The user enter the value of n (2,4,6 or 8) and the code will plot and tell what is angle value that achieves max efficiency and the value of this efficiency.
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Size: 33792 |
Author: Ismail Elbadawy |
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Description: This MATLAB Code plot the aperture efficiency Vs the subtended angle. The user determine the value of n and the code plot and tell what is the angle value that achieves max efficeiency and the value of this efficiency.
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Size: 31744 |
Author: Ismail Elbadawy |
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Description: C++链表解决约瑟夫环问题，问题描述：假设有N个小孩按照序号1，2，，，N围坐成一圈，从第一个小孩开始报数，每次报到n的人退出，接着从下一个人重新开始从1开始报数，下一次再报到n的人退出，
求最后一个留下第几个人；-C++ linked list to solve the problem Josephus, described the problem: Suppose there are N children according to number 1,2,,, N sitting in a circle, starting from the first child reported that the number of people out of every report of n, then from the next to re-start from 1 reported that the number, n, the next person and then report out, seeking the last to leave the first few people
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Size: 5040128 |
Author: 沈宙 |
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Description: L utilisation d intégrateurs limités permet de "clamper" à 0 la valeur basse de Ired et de Vs. Simulink simule des équations mathématiques dans lesquelles le comportement unidirectionnel des semi conducteurs n est pas exprimé. Sans cette précaution, un courant Ired<0 pourrait apparaî tre en régime transitoire.
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Size: 35840 |
Author: chaib |
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Description: 1）匿名用户可以浏览留言内容，在管理员开启“允许匿名用户留言”功能的情况下可以留言。
2）已登录用户可以留言、编辑以及删除自己的留言。
3）管理员具有管理用户（例如添加删除用户），管理留言（删除与回复留言），管理留言本（如设置分页每页显示的留言记录条数，开启/关闭匿名用户与已登录用户留言等）
4）必须采用N层架构（比如三层结构表示层/业务逻辑层/数据访问层）、使用自定义的DBHelper类、界面必须要采用CSS+DIV来进行布局、需要使用校验控件（比如RequiredFieldValidator）。
5）后台数据库需要自行设计（其中需要包含留言者的ip地址，留言日期，留言内容等），必须使用到存储过程。
6）开发环境VS 2005+SQL Server2005。
-1) Anonymous users can view message content, the administrator opens the " Allow anonymous users to comment" feature in case you can leave a message. 2) has been logged users can post, edit, and delete their own comments. 3) administrators with administrative user (for example, add and delete users), Management Message (deleted and reply to messages), management Guestbook (such as setting the paging message Show number of records, turn on/off the anonymous user and logged in user comments, etc. ) 4) must use N-tier architecture (such as three-tier structure of the presentation layer/business logic/data access layer), using a custom DBHelper class, the interface must be used CSS+DIV for layout, you need to use the calibration controls (eg RequiredFieldValidator) . 5) back-end database design their own needs (which needs to include a message' s ip address, message date, message content, etc.), you must use the stored procedure. 6) Development Environment VS 2005+SQL Server200
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Size: 3254272 |
Author: 沈文娟 |
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Description: 用vs编写的一个c示例程序，用于实现阶乘运算。-This C program can Implement factorial calculation, which is a sample program wrote in microsoft visual studio.
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Size: 605184 |
Author: Lorraine Chan |
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Description: 变步长自适应滤波算法，对VS—LMS算法进行了改进，建立了步长因子μ与误差信号e（n）之间另一种新的非线性函数关系．理论分析和计算机仿真结果表明，该关系不仅具有原有算法收敛速度快的优点，而且在低信噪比环境下比原有算法具有更好的抗噪声性能．-The variable step size adaptive filtering algorithm is discussed, and the VS-LMS algorithm is improved. A new nonlinear function relation between the step size factor μ and the error signal e (n) is established. Theoretical analysis and computer simulation results show that the proposed algorithm not only has the advantages of high convergence speed of the original algorithm, but also has better anti- noise performance in the low SNR environment than the original algorithm.
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Size: 1024 |
Author: 曹展宏 |
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Description: 排隊理論
產生exponential分布的 inter-arrival time，Mean 0.25, 0.5, 1, 2
1.統計並劃出Cumulative distribution曲線與其理論曲線
2.時間單位各為1、2、…20單位，分別統計各時間單位之arrival的個數，並劃出Pn(t) v.s t 與其理論值，n取0、1、2、3、4、5，λ取0.5。-Queuing theory produce exponential distribution of inter-arrival time, Mean 0.25, 0.5, 1, 2 1. Cumulative distribution statistics and draw the curve with its theoretical curve 2. Each unit of time is 1, 2, ... 20 units, respectively, each time statistics the arrival of the number of units, and draw Pn (t) vs t and its theoretical value, n take 0,1,2,3,4,5, λ is 0.5.
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Size: 265216 |
Author: 張瑀征 |
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Description: 人工智能实验 n皇后问题 源码 VS工程(AI class homework n Queen problem)
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Size: 4567040 |
Author: JenniferHo
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