Component forensics

Visual sensor technologies have experienced tremendous growth in recent decades, and digital devices are becoming ubiquitous. Digital images taken by various imaging devices have been used in a growing number of applications, from military and reconnaissance to medical diagnosis and consumer photography. Consequently, a series of new forensic issues arise amidst such rapid advancement and widespread adoption of imaging technologies. For example, one can readily ask what kinds of hardware and software components as well as their parameters have been employed inside these devices? Given a digital image, which imaging sensor or which brand of sensor was used to acquire the image? How was the image acquired? Was it captured using a digital camera, cell phone camera, image scanner, or was it created artificially using an imageediting software? Has the image undergone any manipulation after capture? Is it authentic, or has it been tampered in any way? Does it contain any hidden information or steganographic data? Many of these forensic questions are related to tracing the origin of the digital image to its creation process. Evidence obtained from such analysis would provide useful forensic information to law enforcement, security, and intelligence agencies. Knowledge of image acquisition techniques can also help answer further forensic questions regarding the nature of additional processing that the image might have undergone after capture.     

Multimedia information broadcasting using digital TV channels

The structure of a new system used to broadcast multimedia information within a digital TV channel is outlined. The proposed scheme is based on the the Digital Storage Media Command and Control (DSM-CC) functions, and uses a newly developed protocol that allows to efficiently convey multimedia information. Such information has the same characteristics of HTML files used in WWW environments, as it may contain text, images, sounds and animation organized as an hypertext. The transport structure used is the MPEG-2 Transport Stream, which is the most standardized platform for the development of new digital TV services. A prototype software was developed to encode the file system by means of DSM-CC operations and include it in a MPEG-2 compatible Transport Stream     

基于奇异值分解的数字图像水印方法

随着计算机和网络技术的飞速发展,数字图像、音频和视频产品愈来愈需要一种有效的版权保护方法,另外通信系统在网络环境下的信息安全问题也日益显露出来.数字图像水印技术为上述问题提供了一个潜在的解决方案.所谓水印技术就是将数字、序列号、文字、图像标志等版权信息嵌入到多媒体数据中,以起到版权保护、秘密通信、数据文件的真伪鉴别和产品标志等作用.本文提出了一种新的基于奇异值分解的数字水印算法并且对该方法的理论基础给出分析.实验结果表明这种方法要比目前提出的流行算法鲁棒.     

快速响应红外探测器数字降噪研究

通过分析快速响应热释电红外探测器的振动噪声机理和输出电信号的频谱,得到相应结果。根据结果本文提出一种新颖的数字降噪方案,并采用基于FPGA的硬件电路将其实现,在文中对硬件的结构和其中的FPGA代码实现进行了介绍,最后本文给出了降噪之后的实际效果。     

数字签名技术在电子病历中的设计与实现

目的:推进医疗行业的信息无纸化,大力发展数字化医院,完善身份识别和信息安全等问题。方法:通过对我院相关业务的需求分析,引入了数字签名技术来保障数据完整性和不可抵赖性。结果:数字签名技术使医院的业务环境更加安全有效,保证了身份真实和责任明确,用电子签名替代了传统的医生手写签名方式,优化了业务流程。结论:数字签名技术有效推进了医疗行业的信息无纸化,对于医疗信息系统在身份认证、授权管理、责任认定等方面的信息安全的需求有着非常重要的意义。     

Digital optics

The authors discuss digital optics, a technology for processing, transport, and storage of optical digital information. Digital optics offers both the high temporal bandwidth of fiber communications and the high connectivity and information density of optical imaging. The energy dissipation per bit of communicated information, as well as the chip area dedicated to interconnections, can be significantly lower in optics than in high-speed electronics. This motivates the introduction of parallel optical interconnections through free space in communication-intensive areas of digital information processing such as switching in telecommunications and within multiprocessors. Digital optical circuits can be constructed by cascading two-dimensional planar arrays of optical logic gates interconnected in free space. The state of the art and the trends in digital optical information processing systems for optical logic, optoelectronic interfaces, and optical free-space interconnection systems are reviewed     

一种基于数字电视系统的数据传输技术研究

数字电视是较为成熟和先进的信息传输技术，详细介绍一种通过数字电视系统传输数据的方法。     

数字图书馆的构建

数字图书馆是传统图书馆的未来发展方向，国内外对此进行了大量研究。针对目前研究情况，探讨了数字图书馆构建中所面临的数字化信息存储、统一规范的检索标准、海量数字化资源建设、网络设计与安全、多媒体信息的表现、知识产权和著作权以及数字图书馆数据模型方案的设计等相关问题。     

电信运营商信息服务科技能力助力数字政府建设思路

数字政府是数字中国的重要组成部分，引领驱动数字经济、数字社会、数字生态、数字文化全方位协同发展。近年来，我国数字政府建设取得了显著成就，服务效能显著提升。电信运营商坚持主动服务国家战略和经济社会发展需要，具备雄厚的技术、管理、人才等资源优势，可借鉴国外发达国家数字政府建设经验，针对我国数字政府热点问题与发展趋势，从提供咨询设计等专家智力支撑；依托信息基础设施构筑5G、算力网络、人工智能等数字政府能力底座；发挥属地化服务资源优势；推进信令等大数据应用四个方面助力我国数字政府建设工作。     

企业馆藏信息资源数字化建设初探

数字图书馆因其传递信息的便利性和快捷性而成为未来图书馆发展的主要模式。企业图书馆数字化建设的关键是馆藏信息资源的数字化。在数字化资源建设中对馆藏数字化对象、输入设备、数据存储模式等的选择应根据各自的馆藏、人力、财力等资源具体分析，作切合实际的选择。     

基于模糊决策树的电话记录取证分析

Digital evidences can be obtained from computers and various kinds of digital devices, such as telephones, mp3/mp4 players, printers, cameras, etc. Telephone Call Detail Records (CDRs) are one important source of digital evidences that can identify suspects and their partners. Law enforcement authorities may intercept and record specific conversations with a court order and CDRs can be obtained from telephone service providers. However, the CDRs of a suspect for a period of time are often fairly large in volume. To obtain useful information and make appropriate decisions automatically from such large amount of CDRs become more and more difficult. Current analysis tools are designed to present only numerical results rather than help us make useful decisions. In this paper, an algorithm based on Fuzzy Decision Tree (FDT) for analyzing CDRs is proposed. We conducted experimental evaluation to verify the proposed algorithm and the result is very promising.     

Beyond the law

Moore's Law has proven a remarkably useful rule of thumb in the semiconductor industry. But technological progress in industries that rely on partly analogue technology - such as the mobile phone industry - obeys different laws. Digital technology is about information storage and processing: Moore's Law reflects the ability to reduce the amount of energy (electrons) needed to store and read a single bit. Radio technology is about the transport of information. The reasons why Moore's Law is not applicable to analogue technology are discussed. Mobiel phones use analogue technology, which is different to the digital technology described by Moore's Law     

Single-Post Inductive Obstacle in Rectangular Waveguide

A rapidly converging moment solution for electromagnetic scattering by a single inductive post in a rectangular waveguide is obtained. The numerical results show good agreement with Marcuvitz's data as far as this data goes. Furthermore, Marcuvitz's curves are extended to cover data for large posts. This new data should aflow one to design a simply constructed new type of narrow bandpass filter, namely, a filter consisting of large single posts. The successful use of this straightforward moment solution in solving the single-post problem suggests that this technique should prove useful in solving a variety of microwave discontinuities such as those involving thin or thick irises and posts of arbitrary shape.     

Getting more out of eye diagrams [circuit testing]

The eye diagram, so called for its resemblance to a human eye, is a well-established tool. The communications industry uses it to observe and analyze the performance of circuits that drive the transfer of digital data streams. In its simplest form, it is generated on the screen of a storage oscilloscope (analog or digital) by overlaying sweeps of different segments of a long data stream driven by a master clock. The author describes how the eye diagram is used to obtain information about the circuit under test. The advent of the digital oscilloscope has led to improvements in the use of the method. Digital oscilloscopes give engineers the ability to use timing jitter, rise time, pulse width, amplitude, and more than 40 other signal parameters as the basis for making decisions-or, even better, for having automatic test equipment make them. The most powerful digital scopes will even calculate and display such statistical quantities as the mean, minimum, maximum, and standard deviation of these parameters     

一种虚拟光学数据加密的系统实现

本文在虚拟光学数据加密理论模型的基础上,研究一种并行电子系统实现方法.该系统利用TMS320C6701浮点DSP(Digital Signal Processor)实现具有多重锁、多重密钥的高密级多媒体数据加密系统.该系统具有安全性高、加/解密速度快、实时性好、适用范围宽等优点,可用于多种媒体信息如文本、图像、语音、视频等的加/解密.     

Multimedia information broadcasting using digital TV channels

In this paper, the structure of a new system to broadcast multimedia information within a digital TV channel is outlined. The proposed scheme is based on the DSM-CC (digital storage media command and control) functions, and uses a newly developed protocol that allows to efficiently convey multimedia information. Such information has the same characteristics of HTML files used in WWW environments, as it may contain text, images, sounds and animation organized as hypertext. The transport structure used is the MPEG-2 transport stream, which is the most popular standardized platform for the development of new digital TV services. Prototype software was developed to encode the file system by means of DSM-CC operations and include it in a MPEG-2 compatible transport system     

一种基于图像融合的数字水印方案

数字水印是一种新型的多媒体信息版权保护技术，它是在多媒体信息中嵌入标志版权信息的不可感知且难以去除的水印信息，通过检测水印信息来进行版权保护及盗版跟踪，从而有效地弥补了数字加密技术的不足之处。提出了一种具有良好鲁棒性的数字水印方案。由于该方案利用人眼视觉系统把数字水印嵌入到图像的视觉重要区域中，对水印的破坏将会非常困难。     

Radio-over-Fibre access for sustainable Digital Cities

Pervasive broadband access will transform cities to the net social, environmental and economic benefit of the e-City dweller as did the introduction of utility and transport network infrastructures. Yet without action, the quantity of greenhouse gas emissions attributable to the increasing energy consumption of access networks will become a serious threat to the environment. This paper introduces the vision of a ‘sustainable Digital City’ and then considers strategies to overcome economic and technical hurdles faced by engineers responsible for developing the information and communications technology (ICT) network infrastructure of a Digital City. In particular, ICT energy consumption, already an issue from an operating cost perspective, is responsible for 3 % of global energy consumption and is growing unsustainably. A grand challenge is to conceive of networks, systems and devices that together can cap wireless network energy consumption whilst accommodating growth in the number of subscribers and the bandwidth of services. This paper provides some first research directions to tackle this grand challenge. A distributed antenna system with radio frequency (RF) transport over an optical fibre (or optical wireless in benign environments) distribution network is identified as best suited to wireless access in cluttered urban environments expected in a Digital City from an energy consumption perspective. This is a similar architecture to Radio-over-Fibre which, for decades, has been synonymous with RF transport over analogue intensity-modulated direct detection optical links. However, it is suggested herein that digital coherent optical transport of RF holds greater promise than the orthodox approach. The composition of the wireless and optical channels is then linear, which eases the digital signal processing tasks and permits robust wireless protocols to be used end-to-end natively which offers gains in terms of capacity and energy efficiency. The arguments are supported by simulation studies of distributed antenna systems and digital coherent Radio-over-Fibre links.     

Subscriber Line Testing for Digital Switching Offices

This paper presents an overview of subscriber line testing as provided in Northern Telecom's Digital World^®family of host and remote digital switching systems. Capabilities provided in Digital World satisfy the major telco needs related to subscriber line testing. The various products incorporate interfaces to external test systems as well as internal line test facilities. A new subscriber line measurement technique is identified. It offers further advantages in speed and accuracy and has many potential applications in the analog and digital switching environments.     

数字图书馆IP网络存储管理技术研究

随着日益增长的数据信息需求,对数字图书馆的存储技术和存储设备提出了更高的要求,传统的存储设备和存储技术已经无法满足数字图书馆的存储要求。本文从设备成本,系统可靠性,兼容性,安全性等方面对常用的几种存储技术进行分析和比较,探冲符合现阶段数字图书馆存储要求的存储方式,并为未来存储技术的发展和运用进行战略性思考。