近年來，近距離無線傳輸技術是發(fā)展最快、最引入注目的技術，而ZigBee恰恰是填補了低速率無線通信技術的空缺，與其他標準在應用上相得益彰。它專注于近距離傳輸，成本低、同時入門檻也低，雖然其出現(xiàn)較晚，但目前已經得到人們越來越多的關注，成為無線技術研究的一個新熱點。 本文在詳細分析了傳統(tǒng)的抄表方式和無線抄表系統(tǒng)的發(fā)展狀況以及相關的無線數(shù)據(jù)傳輸技術的基礎上，提出了基于ZigBee技術的無線抄表系統(tǒng)的方案。論文在研究ZigBee組網(wǎng)技術的基礎上，設計了基于ZigBee開發(fā)平臺的無線嵌入式抄表系統(tǒng)，編寫了相應的軟件，完成了相應的調試和分析，并進行了系統(tǒng)的可靠性、實時性和安全性等問題分析。為了減少系統(tǒng)由于節(jié)點路由而造成的功耗損耗過大的問題，本文在組網(wǎng)應用過程中采用Tree+AODVjr的路由算法，從而保持系統(tǒng)能夠保持較小功耗的情況下進行數(shù)據(jù)的多跳路由，同時以ARM S3C2410為核心實現(xiàn)了基站設計，實現(xiàn)小區(qū)電表數(shù)據(jù)的集中采集，并通過GPRS/GSM模塊實現(xiàn)基站和抄表中心的數(shù)據(jù)傳輸和實時控制，在此基礎上，對抄表系統(tǒng)軟件也進行了相應的設計。 通過單點對單點、星形網(wǎng)絡數(shù)據(jù)傳輸實驗，取得了相應的實驗數(shù)據(jù)，對于協(xié)議的特點、系統(tǒng)可靠性和功耗情況有了整體把握，為今后ZigBee技術的進一步研究和應用打下了堅實基礎。 實驗結果顯示，本文提出的方案切實可行，并且采用ZigBee技術具有節(jié)約資源、操作方便、可靠性高而且易于管理等特點，基站和系統(tǒng)利用較為成熟的GPRS/GSM網(wǎng)絡技術進行通訊，既滿足了實時性要求，又降低了成本。
標簽： ZIGBEE 嵌入式 自動抄表系統(tǒng)
上傳時間： 2013-06-27
上傳用戶：kjgkadjg
基于FPGA技術的網(wǎng)絡入侵檢測是未來的發(fā)展方向，而網(wǎng)絡包頭的分類是入侵檢測系統(tǒng)的關鍵。 文章首先介紹了FPGA技術的基本原理以及其在信息安全方面的應用，接著介紹入侵檢測系統(tǒng)以及FPGA技術在入侵檢測系統(tǒng)中的應用。 分析了幾種比較出名的網(wǎng)絡包分類算法，包括軟件分類方法、TCAM分類算法、BV算法、Tree Bitmap算法以及端口范圍分類算法。 在此基礎上，文章設計了一個基于FPGA技術的入侵檢測系統(tǒng)包分類的基本框架圖，實現(xiàn)框架圖中的各個基本功能模塊。在實現(xiàn)過程中，提出了一類結合三態(tài)內容可尋址內存(TCAM)和普通存儲器(RAM)的網(wǎng)絡包包頭分類方案。我們將檢測規(guī)則編號并位圖化，使用RAM存儲與包頭結構相關的規(guī)則位圖，通過TCAM上的數(shù)據(jù)匹配操作，快速關聯(lián)待分析的網(wǎng)絡數(shù)據(jù)包與入侵檢測規(guī)則。文章還討論了網(wǎng)包頭分類方法的優(yōu)化算法，將優(yōu)化算法與未優(yōu)化算法在速度和空間上進行比較。此外，還討論了對Snort的規(guī)則庫進行整理和規(guī)則化的問題。 最后，對所設計的包頭分類匹配模塊在Quartus II進行仿真評估，將實驗結果與已有的一些分類算法進行了比較。結果說明，本設計在匹配速度和更新速度上有優(yōu)勢，但消耗了較多的存儲空間．
標簽： 入侵檢測系統(tǒng) 網(wǎng)絡 包分類 技術研究
上傳時間： 2013-07-17
上傳用戶：gonuiln
· 摘要： 本文利用了十六位SPCE061A單片機的強大的DSP功能,實現(xiàn)了特定發(fā)音人識別(Speaker Dependent)功能.結合大容量的FLASH存儲器,成功地實現(xiàn)將語音播放與識別技術應用于智能家居控制系統(tǒng)中.另外,詳細介紹了具有語音識別功能的新一代智能家居控制系統(tǒng)的硬件配置與軟件流程,從而在實現(xiàn)系統(tǒng)功能的同時,將低成本、低功耗與友好人機界面有機結合起來.
標簽： 單片機 語音識別 智能家居控制系統(tǒng) 實現(xiàn)方案
上傳時間： 2013-04-24
上傳用戶：xwd2010
Abstract: Most magnetic read head data sheets do not fully specify the frequency-dependent components andare often vague when specifying other key parameters. In some cases, the specifications of two very similarheads from two different manufacturers might be quite different in terms of parameters specified and omitted.The limitations in the data sheets make designing an optimum card reading system unnecessarily difficult andtime consuming. This document outlines a strategy to overcome the above shortcomings and offers guidelinesto overcome the noise issues.
標簽： MCR 噪聲環(huán)境 磁卡讀寫器
上傳時間： 2013-11-13
上傳用戶：dysyase
Control systems are becoming increasingly dependent on digital processing and so require sensors able to provide direct digital inputs. Sensors based on time measurement, having outputs based on a frequency or phase, have an advantage over conventional analogue sensors in that their outputs can be measured directly in digital systems by pulse counting.
上傳時間： 2013-10-08
上傳用戶：wuyuying
The #1 Step-by-Step Guide to labviewNow Completely Updated for labview 8! Master labview 8 with the industry's friendliest, most intuitive tutorial: labview for Everyone, Third Edition. Top labview experts Jeffrey Travis and Jim Kring teach labview the easy way: through carefully explained, step-by-step examples that give you reusable code for your own projects! This brand-new Third Edition has been fully revamped and expanded to reflect new features and techniques introduced in labview 8. You'll find two new chapters, plus dozens of new topics, including Project Explorer, AutoTool, XML, event-driven programming, error handling, regular expressions, polymorphic VIs, timed structures, advanced reporting, and much more. Certified labview Developer (CLD) candidates will find callouts linking to key objectives on NI's newest exam, making this book a more valuable study tool than ever. Not just what to d why to do it! Use labview to build your own virtual workbench Master labview's foundations: wiring, creating, editing, and debugging VIs; using controls and indicators; working with data structures; and much more Learn the "art" and best practices of effective labview development NEW: Streamline development with labview Express VIs NEW: Acquire data with NI-DAQmx and the labview DAQmx VIs NEW: Discover design patterns for error handling, control structures, state machines, queued messaging, and more NEW: Create sophisticated user interfaces with tree and tab controls, drag and drop, subpanels, and more Whatever your application, whatever your role, whether you've used labview or not, labview for Everyone, Third Edition is the fastest, easiest way to get the results you're after!
上傳時間： 2013-10-14
上傳用戶：shawvi
Complete support for EBNF notation; Object-oriented parser design; C++ output; Deterministic bottom-up "shift-reduce" parsing; SLR(1), LALR(1) and LR(1) table construction methods; Automatic parse tree creation; Possibility to output parse tree in XML format; Verbose conflict diagnostics; Generation of tree traverse procedures
標簽： Object-oriented Deterministic Complete notation
上傳時間： 2014-11-29
上傳用戶：kr770906
此軟件應用了桌面表單，自定義菜單，常用工具條，數(shù)據(jù)表加密，TREE等控件技術。新學者可以借鑒。人性與個性化的界面設計，嘿嘿，還真值得一看
上傳時間： 2015-01-18
上傳用戶：遠遠ssad
This scheme is initiated by Ziv and Lempel [1]. A slightly modified version is described by Storer and Szymanski [2]. An implementation using a binary tree is proposed by Bell [3]. The algorithm is quite simple: Keep a ring buffer, which initially contains "space" characters only. Read several letters from the file to the buffer. Then search the buffer for the longest string that matches the letters just read, and send its length and position in the buffer.
標簽： initiated described modified slightly
上傳時間： 2014-01-09
上傳用戶：sk5201314
Contains a complete archiver by Haruhiko Okumura. The archiver uses an LZ engine whose output is compressed with static Huffman. The file is chopped into pieces which all get their own independent set of Huffman tree s. ARJ 2.41, ZIP 2.0 and PKZIP 2.04g use essentially the same method. ZOO and LHA even use excactly the same method.
標簽： archiver Contains complete Haruhiko
上傳時間： 2014-01-17
上傳用戶：himbly
