查询词典 digital coding

Speech coding is one of the basic and most important components in digital communication networks. 2. 4kb/s and even lower bit-rate speech coding is always one of the most important research topics in the area of speech coding.

数字语音的编码传输是整个数字化通信网中最重要、最基本的组成部分之一。2.4kb/s甚至更低速率的语音编码技术一直是语音编码中重要的研究课题。

The main content of this thesis includes six parts. First of all, it is a comprehensive systematic introduction about RSA algorithm including the present application situation and principle of RSA algorithm----producing big prime numbers and secret keys, the encryption arithmetic for information and the decryption for secret information, which establish the theory foundation for achieving concrete; secondly, it introduces some basic conception of RSA digital signature and theory of digital signature realizing process; thirdly, it introduces the basic principle of MD5 algorithm; fourthly, it states design and realization of RSA digital signature in detail. The main modules includes producing RSA secret keys, implementation of RSA encryption algorithm and decryption algorithm, producing message digest and realizing digital signature and verification by RSA; the fifth, it carries on testing entirely, analyzing and improving for this system;The sixth, it analyses the security of RSA digital signature and points out the development direction of RSA digital signature.

本文主要研究的内容包括：第一，对RSA算法进行了全面系统的介绍，包括RSA算法的应用现状和原理—大素数的产生、密钥对的产生、对明文的加密运算和密文的解密运算，为具体实现打下了理论基础；第二，介绍了RSA数字签名的一些基本概念和数字签名的理论实现过程；第三，对MD5算法基本原理的介绍；第四，详述了RSA数字签名的设计与实现，主要实现的模块包括RSA密钥的产生，RSA加密算法和解密算法的实现，消息摘要MD的生成以及利用RSA算法实现数字签名和签名的验证；第五，对该系统进行了整体的测试和分析改进；第六，分析了RSA数字签名的安全性，指出了RSA数字签名的发展方向。

In this paper, the concept of network security and security structures of OSI and Internet is introduced, and various threats confronting the computer network are also discussed. Several kinds of network information security technologies, including firewall technology, virtual private network, intrusion detection system, data encryption technology, identity authentication and security protocol etc. are also examined. The security of internal network is the biggest problem in the construction of each network. The solution to this problem lies in setting up a firewall. The theory of a firewall and the approach to its actualization is studied. Intrusion detection system, an important part of the computer network security system, has gained extensive attention. IDS monitors the computer and network traffic for intrusion and suspicious activities. It not only detects the intrusion from the extranet hacker, but also the intranet users. The emergence of virtual private network paves the way for realizing secure connection of LAN quickly and at a relatively low cost. The concept, function, key techniques, including the tunnel technology, and the ways to realize VPN are expounded in this paper. Also introduced is the data encrypt network technology, which is called the soul of computer network security, such as digital digest, digital signature, digital certificate, digital encrypt arithmetic and so on. At the same time, the principle and the process of implementing network security by digital certificate and digital signature, the basic principle and characters of security protocols, and finally, three of the security protocols, concerning the security problems in network, IPsec, SLL and SET are analyzed in detail Computer network system should be a system of dynamic defence, both dynamic and static, passive as well as active, and even offensive, combined with management and technology.

本文系统地介绍了网络安全的概念、OSI及Internet的安全体系结构，并讨论了计算机网络面临的各种安全威胁；内部网络的安全问题是每个建网单位面临的最大问题，可以认为防火墙技术是解决网络安全的一个主要手段，本文研究了防火墙的原理及其实现手段；作为一种主动的防御措施，入侵检测系统作为网络系统安全的重要组成部分，得到了广泛的重视，TDS对计算机和网络资源上的恶意使用行为进行识别和响应，不仅检测来自外部的入侵行为，也监督内部用户的未授权活动；虚拟专用网技术的出现，为实现网络间的连接提供了快速安全但又相对便宜的手段，本文较深入的探讨了实现VPN的隧道技术，并对VPN的概念、功能、实现途径、基本构成、关键技术及发展前景等问题进行了全面论述；数据加密技术是网络安全核心技术之一，本文从数据加密算法、数字摘要、数字签名及数字证书等几方面简要介绍了数据加密技术，并分析用数字证书和数字签名实现网络安全的原理和过程；对安全协议的基本原理、主要特点进行了较为深入的研究，并就网络的安全性问题剖析了三种安全协议：IPsec协议、SLL协议和SET协议。

In this dissertation, digital lock-in detection techniques under integer period sampling and non-integer period sampling are separately investigated (1) Under integer period sampling, digital signal sequence is acquired through sampling the measured signal, but digital reference sequence is acquired through mathematical operation, then digital lock-in detection can be realized by calculating crosscorrelation function of digital signal sequence and digital reference sequence Harmonic measure is also analyzed, and a method of measuring harmonic of a periodic signal under aliasing is put forward.

本文对使用采样ADC把模拟信号转换为数字信号并通过计算数字信号的相关函数来实现锁定检测的技术进行了研究，在此基础上设计了一个多功能的数字LIA并在一些科学实验中进行了应用。本文对整周期采样和非整周期采样时的数字锁定检测技术分别进行了研究。(1)在整周期采样时，对被测信号进行采样得到信号序列，而参考序列由数学运算得到，通过计算信号序列和参考序列的互相关函数就可实现锁定检测。

For preparing for the researches of text digital watermarking and advantaging other researchers" development when using the Chinese mathematical expression theory, this paper designs and realizes a development platform of Chinese mathematical expression. It has been proved by experiments that the platform"s function, execution speed and stability can satisfy the requirements of conversion and operation of enormous data.This research found out that the structure information of Chinese have plenty redundant information that can be used by the Chinese mathematical expression for the digital watermarking, the data embedded can possess better robustness. Based on this finding, this paper designs a kind of text digital watermarking method of embedding watermarking by using Chinese structure, and realizes the method by using the Chinese mathematical expression platform.Considering the watermarking embedding algorithms importance to the robustness of the text digital watermarking, this paper makes fully use of the advantage of the Chinese mathematical expression theory to design a kind of layered text method, which has being realized by using the Chinese mathematical expression platform. The layered text method can handle the text as a solid structure, and the embedding data havepreferable robustness.Finally, based on the researches of the text digital watermarking method and the text layered method, this paper integrates the method of making use of the Chinese structure embedding watermarking with the robust algorithm based on text layered, and realizes a brand-new text digital watermarking method. Proved by lots of experiments, this brand-new method has good robustness and better invisibility.

为了为研究工作做准备和方便其他使用汉字数学表达式理论体系的人进行开发，本文基于汉字数学表达式理论设计实现了一个汉字数学表达式平台，实现了Unicode汉字集中的汉字、汉字数学表达式、汉字的Unicode码之间的相互转化、依据汉字数学表达式提取汉字的结构信息、由汉字数学表达式在非中文平台上不依赖字库显示汉字的图像等功能，使用复合文档技术和流压缩技术进行数据的存储，使用对汉字数学表达式进行二叉树拆分来处理汉字数学表达式中包含的信息，使用自定义哈希函数来提高运行速度，实验证明，该平台功能、速度和稳定性完全能满足大量数据的转化和运算要求；通过研究表明汉字的结构信息中存在大量可使用汉字数学表达式理论加以利用的水印加载空间，加载在该空间的数据可以具有较好的鲁棒性，基于此，本文设计了一种利用汉字结构加载水印的文本数字水印方法，并使用汉字数学表达式平台将其实现；由于水印嵌入算法对于文本数字水印的鲁棒性至关重要，本文充分利用汉字数学表达式理论的优点，设计了一种文本分层的方法，并使用汉字数学表达式平台将其实现，使文本成为一个立体的空间，使嵌入在其中的数据具有更好的鲁棒性；最后在基于汉字数学表达式的文本数字水印嵌入方法的研究和基于汉字数学表达式的文本分层方法的研究的基础上，结合利用汉字结构嵌入水印的方法和基于文本分层的抗攻击文本水印嵌入算法实现了一种全新的文本数字水印方法，经实验证明，该方法有良好的鲁棒性和较好的隐蔽性。

In order to realize the compatible communications system between digital TETRA and analogy MPT1327. Communications protocol between digital radio and control center is defined. Emergency call software flow for TETRA and MPT module is designed, and also state information sending and receiving for TETRA and MPT module is designed in this communication system. By comparing several solutions, switch methods between analogy TETRA communications and digital TETRA communications are designed including manual-switch and soft-switch. In the article, coding module of receiving and sending equipments in TATT analogy TETRA communications is described, so that it can be compatible with NOKIA network equipments and it also can improve the availability rate of the trunk system. In order to realize the integration of digital TETRA communication and analogy MPT1327 communications, double- frequency antenna system is researched.

通过几种车载电台解决方案比较，设计了相应的模拟集群通信系统与数字集群通信系统的切换方法，其中包括人工切换和软切换，实现了模拟与数字集群兼容的一体化移动列车调度电台解决方案；为了实现数字集群通信系统与模拟集群通信系统以及NOKIA与TAIT模拟集群通信系统之间的相互兼容，设计了新的数字车载电台与控制中心之间的通信协议；系统设计了用于数字集群通信模块的紧急呼叫通讯流程，以及设计了用于模拟集群通信模块状态信息发送与接收流程，以满足列车无线调度的运营要求；论文还论述了对TAIT模拟集群收发设备编码模块的改造，使之能与NOKIA的集群设备相兼容，提高了集群设备的利用率，为在NOKIA模拟集群通讯模块停产后寻找了一种可替代的兼容解决方案；为了实现数字集群通信系统与模拟集群通信系统设备的综合，论文还探讨了本工作所需专用的双频段的天线系统。

Cyclic Redundancy check code is recommended by International Telecommunications Organization , used in the digital communication system error control coding way (given several coding generator polynomial), they have been widely used by the people in the digital communication system.

循环冗余检错编码是国际通信组织推荐的用于数字通信系统的差错控制编码方式（给出了几种编码的生成多项式），已被人们在数字通信系统中广泛地使用。

Blend various advantages of the coding project of the parameter audio frequencies in the meantime, carried on adjustment on the coder structure, have to a certain signal more the mold piece of coding result, if wave structure analytical transformation short time of the mold piece, double the composition examine and double the transformation short time mold piece etc. is an options to bring into coder, from user while coding according to small together source voice document of small together characteristics, decide whether use and how use, but these vivid constitutions can through a code flow in define several good to mark ratio in advance tell a decoding machine especially, constituting decoding machine is little with complications to without direct influence.

同时融合多种参数音频编码方案的优点，在编码器结构上进行了调整，将只对某类信号有较好编码效果的模块，如谐波结构分析模块、双变换短时成分检测与双变换短时模块等，作为选项纳入到编码器中，由使用者在编码时根据小同源声文件的小同特点，来决定是否使用和如何使用，而这些灵活的设置都可以通过码流中预先定义好的几个标示比特位来告知解码器，对解码器本身的构成与复杂度少没有直接的影响。

The analytical properties of arithmetic coding are investigated, which include the nested intervals property of arithmetic coding, the convergence of arithmetic coding, the concepts of an arithmetic code number and of arithmetic code mapping.

这些分析性质丰富了算术编码的理论，在本文一些重要结论的证明中得到了应用，并简化了证明。

Referring to HMIS public data coding criterion, parts coding management module was designed and established, and parts coding automatic generation function was realized. According to the data collection methods in the reliability theory, maintenance record collection principle was determined, and maintenance record management module was established. Then, by using reliability theory and mathematical statistics method, data statistic analysis and malfunction analysis modules were established, and components failure data statistics, choosing of life distribution law, and predicting of maintenance period were realized.

参照HMIS公用数据编码规范，设计并建立了零件编码管理模块，实现零件编码自动生成功能；根据可靠性理论中数据的收集方法，确定了维修记录收集原则，建立了维修记录管理模块；继而，利用可靠性理论及数理统计方法中对数据的统计分析，建立了数据统计分析、故障分析模块，实现了对零部件故障数据的统计、寿命分布规律的选择及对维修周期的预测。

Fostering the concept of multi-culture firmly and mastering the development of advanced culture correctly are conductive to resisting terrorism, separatism of nationalities and ultraism of religion, which is of great academic theoretical, immediate and profound historical si...

牢固树立多元文化的理念和正确把握先进文化的发展方向，有助于在世界范围内自觉地抵制恐怖主义，民族分裂主义和宗教极端主义。不仅具有重大的学术理论意义，而且也具有重大的现实意义和深远的历史意义。

But if anyone walks in the night, he stumbles, because the light is not in him.

11：10 若在黑夜行走，就必碰跌，因为那光不在他里面。