条件接收系统中解扰器的设计与实现

介绍数字视频广播（Digital Video Broadcasting，DVB）条件接收系统的系统结构，详细分析了条件接收系统的工作原理，并给出条件接收系统的解扰器工作流程及实现方案。     

调制光安全保护系统的设计

介绍了利用红外线的发射与接收所构成的光束保护系统。红外线的发射与接收形成一“安全网” ,利用其档光性能 ,可以实现安全防范功能。为提高系统抗干扰性能 ,采用调制的红外光线 ,经过信号处理 ,驱动继电器动作 ,从而实现报警和保护。重点阐述了光束保护系统的基本工作原理 ,并给出了主要硬件原理图。     

实现自动化下变频接收的方案研究

本文介绍了下变频的基本原理,以及如何利用下变频器HSP50216对不同的调制信号进行解调,并给出了一个接收系统设计方案,利用HSP50216具有四个独立可编程通道的特点和相位自适应解调原理,实现针对发送端的变化的自动化接收。     

一种基于蓝牙的交互式系统设计与实现

随着无线互联技术和移动终端技术的发展,手机等移动终端用户对蓝牙产品的功能提出了更高的要求。蓝牙采用推送技术进行数据传输,用户只能选择是否接收,不能对蓝牙发送端的数据进行自主交互浏览。采用J2ME和蓝牙技术实现一种在移动蓝牙终端上使用的交互式系统,有效地利用了J2ME 跨平台的优势,以及蓝牙传送数据易用性和实用性等优点。根据对JSR82规范提供的Java蓝牙无线技术API的研究,给出了蓝牙交互式系统的设计方案和系统结构。通过J2ME的无线应用开发包和MIDlet编程模型,实现了交互式系统。     

HOOK技术在DRM中的应用研究

本文在对HOOK技术特点和DRM系统功能需求分析的基础之上,指出了HOOK技术在DRM中的典型应用,找到了防止文件内容复制的新方法,并给出了其实现的方法。     

调制光安全保护系统的设计

介绍了利用红外线的发射与接收所构成的光束保护系统，红外线的发射与接收形成一“安全网”，利用其挡光性能，可以实现安全防范功能，为提高系统抗干扰性能，采用调制的红外光线，经过信号处理，驱动继电器动作，从而实现报警和保护，重点阐述了光束保护系统的基本工作原理，并给出了主要硬件原理图。     

安全Push VOD DRM系统的设计与分析

Push VOD系统的推行和发展给数字内容保护技术带来了更大的挑战,传统的条件接收技术已不能满足Push VOD系统的安全性需求。结合现有数字版权保护技术,提出了一种Push VOD DRM系统的设计方案。该系统将DRM技术与CA技术融合,对整个系统的密钥管理逻辑进行了深入的研究,实现对数字内容整个生命周期的保护,满足了Push VOD系统的安全性需求,也为Push VOD系统提供了付费业务的支撑。     

基于AVS的广播式手机电视系统

提出并实现了一种基于AVS的广播式手机电视系统,包括音视频数据的实时编码、系统层复用、T-DMB信号发射与接收、PC及手机平台的解码回放等,重点介绍了音视频编码器中的AVS视频编码算法的优化和复用器的实现,通过实验对编码器的性能进行了测试,对播放端的播放效果进行了分析。实验结果表明,AVS能够很好地应用于手机电视。     

磁浮列车间隙传感器无线在线检测系统设计

为实现磁浮列车间隙传感器的无线在线检测,设计了一种基于蓝牙的无线检测系统.该系统由数据采样、数据接收处理与无线发射模块构成.系统采用成熟的蓝牙传输模块,缩短了设计周期,具有成本低、体积小、可靠性高等特点.检测系统的实际使用表明,系统结构简单,大大降低了传感器检测维护的工作量,从而提高了效率.     

无线随机动态操作点阵式大屏幕系统的设计

无线随机动态操作点阵式大屏幕系统的设计是对当前点阵式大屏幕提出的一个创新。章详细论述了系统结构及具体实现方法，建立了较完善的无线操作与随机动态系统。系统分为手写板控制及发射子系统，编码无线传输子系统，大屏幕及控制显示子系统。同时提供了系统结构图，发射器、接收器、接收控制电路图。     

全球数字广播系统音频编码器的软件实现

全球范围的数字广播系统DRM(Digital Radio Mondiale),是一种针对30MHz以下频段的数字声音广播系统。和传统广播系统相比,DRM数字广播系统在声音质量上是模拟调幅广播无法比拟的。这其中的关键之一在于DRM系统引入了新的信源编解码技术——MPEG-4标准的AAC(Advanced Audio Coding,先进音频编码)。在分析符合DRM标准的AAC音频编码器原理基础上,提出了一种改进的离散余弦变换算法,并在PC上实现了基于该算法的AAC音频编码器。实验表明,该软件编码器能够满足DRM系统实时性要求。     

Evaluation of the DRM and the Time for Preventive Maintenance for Aging Software

An attempt to capture software aging and specify when to do preventive maintenance (PM) is presented in this paper. A composite measure termed the DRM, Deteriorating Response Measure, is defined. It is based on the analysis of the deteriorating speed of the software against time and load. This speed is characterized as follows: (1) It decays with increased load. (2) It does not increase again when the load decreases, this indicates loss of elasticity. The DRM is mathematically formulated based on a queueing system model.Specifying when to do preventive maintenance depends on the decision maker's perspective of the manifestation of aging. It is tried here to formalize this dependence. Three degrading performance metrics are defined for a DRM: (1) Decaying restored speed value. (2) Increasing speed offset ratio (recoverability index). (3) Increasing operation interval offset. These metrics can be used singly or aggregately in a DRM to specify when to do preventive maintenance. Results of model testing are also shown.This work can be part of an on-line procedure that calculates performance indexes for a server type software system like a web browser, an operating system, a database, and helps in the decision to do preventive maintenance for aging software.     

A personal mobile DRM manager for smartphones

In this paper we report on our experience in building the experimental Personal Digital Rights Manager for Motorola smartphones, an industry first.Digital Rights Management allows producers or owners of digital content to control the manner in which the content is consumed. This may range from simply preventing duplication to finer access policies such as restricting who can use the content, on what devices, and for how long. In most commercial DRM systems, the average end user plays the role of content consumer, using DRM protected content made available by a service. Here we present a personal digital rights system for mobile devices where the end user has the ability to place DRM protection and controls on his or her own personal content.We designed the personal DRM system to allow users of a mobile device to transparently define controls and generate licenses on custom content and securely transfer them to other mobile devices. A user is able to define and restrict the intended audience and ensure expiration of the content as desired. Compatible devices automatically detect each other and exchange credentials. The personal DRM system on each device safely enforces the content usage rules and also handles moving licenses between devices while preventing leakage of content. We implemented a prototype of our system on Motorola E680i smartphones.     

DRM中流媒体加密密钥切换技术研究与实现

针对数字版权管理（DRM）系统中流媒体的内容加密密钥不易更换的问题和基于OMA DRM2．0规范与ISO13818-1 MPEG 2 TS标准框架,提出提前下发期、密钥过渡期及切换时间窗的机制和严密的内容加密密钥切换时序流程,实现流媒体内容加密密钥平滑切换,提高DRM系统安全性,不影响用户正常收看流媒体节目。     

A flexible and lightweight user‐demand DRM system for multimedia contents over multiple portable device platforms

With the rapid development of technology, digital multimedia has been widely utilized. Access of multimedia contents has become a daily routine. Although multimedia brings ease and convenience for content sharing, it also makes piracy more feasible. For example, it is easy to upload a copyrighted video to YouTube without the owners' permission. Authors and merchants are very much in need of protecting their intellectual property and commercial profits. Digital right management (DRM) systems are provided to fulfill this desire. DRM is a collection of techniques used to control access to copyrighted materials. Because current enterprise DRM solutions are not allowed for customized modification, they cannot fit in our considered scenario perfectly. As a result, we propose a secure DRM system with a design based on user demands, where a consumer can access contents only on authenticated devices until the authorization expires. Our DRM scheme involves a series of robust cryptosystems including AES, SHA‐256, and RSA. Applications as DRM agents are implemented on Windows, Mac OS, Android, and iOS platforms. Moreover, we modularized the DRM components for easy extension and integration. For better performance on low‐end devices, parameters of encryption are introduced, namely, the key size and the encryption density. We addressed the mask shift problem caused by random access and implemented the device identifier acquirement. The DRM system also proved to have high security and good performance in our analysis. Copyright © 2017 John Wiley & Sons, Ltd.     

基于SuperV的DRM基带信道编码调制器设计

介绍了基于SuperV微处理器芯片的DRM(Digital Radio Mondiale)发射机数字基带部分的设计和实现。该系统包括信道编码器和调制器,它的内部功能和外部特性完全符合ETSI ES201980和相关标准。基带信道编码调制器通过PCI接口输入DRM源编码信号,并通过AES接口输出调制信号,其软件采用模块化设计,可以根据用户需求灵活配置。同现有的发射机基带处理模块相比,具有成本低,易于调试、可灵活配置等特点。     

工作流环境下数字内容保护系统研究与实现

针对目前工作流系统中对敏感数字内容缺乏有力的安全保护的问题,研究并实现了一种在工作流环境下敏感数字内容流转安全保护系统。该系统基于数字版权管理系统(DRM)紧密结合工作流系统,通过使用并扩展工作流过程定义语言XPDL,使得数字版权管理系统能够充分利用工作流流程信息,解决了数字内容权限与工作流系统动态连接问题,从而实现了在不安全的网络环境下数字内容的安全分发与流转。     

Production Protection to Copy(right) Protection: From the 10NES to DVDs

Much of what modern digital rights management (DRM) systems attempt to accomplish was actually forcefully implemented on videogame consoles beginning with the Nintendo Entertainment System (NES) and SEGA Genesis system in the early 1980s. Examining the links between modern DRM mechanisms and these early production and copy protection systems can help contextualize the future of media production and access.     

数字版权管理中eBook安全机制研究

DRM系统的安全性依赖于其信任组件的安全性，该信任组件处于非安全的环境，其安全模型与基于互联网的系统的安全模型有着本质的区别。本文讨论了当前DRM系统的信任组件所采用的安全技术，并着重分析了基于DRM的电子书管理策略和信息组件模型的开发，提出了一个基于机器硬件指纹识别的DRM技术方案，该模型的实现将对数字图书馆的构建具有重要的实际意义。     

基于Terra的数字版权管理设计及实现

文章提出了一个基于Terra的数字版权保护平台的设计和原型系统并研究分析了一些应用实例。