数字化战场的技术体系结构

阐述了信息制胜战中数字战场的三种体系结构（作战体系结构、系统体制结构与技术体系结构）及信息系统技术体系近几年的发展；介绍了信息化战场提出的几种技术体系结构，进而分析指出了数字化战场发展过程中所需要开发的各种信息业务和应当注意加强研究的技术方面。     

以数字搜索树表示的二值图象的几何变换

本文介绍以数字搜索树表示的二值图象的一种几何变换算法，文中讨论了四分区与正四边区的基本关系，输出ＤＳＴ结点成立的充分条件，给出了完整的几何变换算法并对算法的复杂性作了分析。     

公安110报警指挥系统组网设计

１１０是电话网中的匪警特服号，现代信息化社会的发展要求１１０接警响应迅速而准确，本文介绍了公安１１０报警指挥系统的组成原理，给出了该系统与公共市话网和公安专网的组网实现方法，并对工程设计中的系统可靠性问题进行了详细的讨论，该系统也可用于１１９报警等其待服业务。     

电子引伸计的数字智能化研究

由于目前的电子引伸计精度不高、不快捷、智能化程度不高,对其数字智能化方向的研究十分必要。从数字智能式电子引伸计的特点、关键技术、技术指标及应用入手,制定开发的技术路线,并介绍相应的信号处理技术。     

A low power and small area all digital delay-locked loop based on ring oscillator architecture

A 133-500 MHz,5.2 mW @500 MHz,0.021 mm2 all digital delay-locked loop(ADDLL)is presented.The power and area reduction of the proposed ADDLL are achieved by implementing a high frequency ring oscillator(ROSC)to count the reference clocks such that the one-clock cycle delay chain and the phase detector in a conventional Master block are no longer needed.The proposed ADDLL has better immunity to PVT(process,voltage,and temperature)than most conventional DLLs,which do not update the control word signals after the locking process,since the control signals for slave delay line are updated in every 256 reference cycles.Fabricated in 0.13 um CMOS process,the measured RMS jitter is 10.83 ps at 500 MHz while the RMS jitter of the input signal is 9.97 ps.     

数字水印攻击及对策分析

数字水印技术作为数字媒体版权保护的重要手段越来越引起人们的重视。文章讨论了数字水印的概念、特征,重点介绍了数字水印的鲁棒性及影响数字水印鲁棒性的因素,总结和分析了数字水印主要攻击方式并提出相应的应对措施。     

An oblivious fragile watermarking scheme for images utilizing edge transitions in BTC bitmaps

As one of the famous block-based image coding schemes,block truncation coding(BTC) has been also applied in digital watermarking.Previous BTC-based watermarking or hiding schemes usually embed secret data by modifying the BTC encoding stage or BTC-compressed data,obtaining the watermarked image with poorer quality than the BTC-compressed version.This paper presents a new oblivious image watermarking scheme by exploiting BTC bitmaps.Unlike the traditional schemes,our approach does not really perform the BTC compression on images during the embedding process but utilizes the parity of the number of horizontal edge transitions in each BTC bitmap to guide the watermark embedding and extraction processes.The embedding process starts by partitioning the original cover image into non-overlapping 4×4 blocks and performing BTC on each block to obtain its BTC bitmap.One watermark bit is embedded in each block by modifying at most three pixel values in the block to make sure that the parity of the number of horizontal edge transitions in the bitmap of the modified block is equal to the embedded watermark bit.In the extraction stage,the suspicious image is first partitioned into non-overlapping 4×4 blocks and BTC is performed on each block to obtain its bitmap.Then,by checking the parity of the number of horizontal edge transitions in the bitmap,we can extract one watermark bit in each block.Experimental results demonstrate that the proposed watermarking scheme is fragile to various image processing operations while keeping the transparency very well.     

A robust watermarking algorithm based on QR factorization and DCT using quantization index modulation technique

We propose a robust digital watermarking algorithm for copyright protection.A stable feature is obtained by utilizing QR factorization and discrete cosine transform(DCT) techniques,and a meaningful watermark image is embedded into an image by modifying the stable feature with a quantization index modulation(QIM) method.The combination of QR factorization,DCT,and QIM techniques guarantees the robustness of the algorithm.Furthermore,an embedding location selection method is exploited to select blocks with small modifications as the embedding locations.This can minimize the embedding distortion and greatly improve the imperceptibility of our scheme.Several standard images were tested and the experimental results were compared with those of other published schemes.The results demonstrate that our proposed scheme can achieve not only better imperceptibility,but also stronger robustness against common signal processing operations and lossy compressions,such as filtering,noise addition,scaling,sharpening,rotation,cropping,and JPEG/JPEG2000 compression.     

PACS系统架构与数字化医院建设

随着我国科技的快速发展和对医院制度的改革,越来越多的新科技引进到医院管理中,医院逐渐步入数字化管理。将PACS系统新型技术应用到医院中,使得医院信息化建设由以病人费用为中心的收费信息,转变为以病人信息为中心的临床信息,全面地解决了医院数字化存档及通信问题,提升了医院信息化管理层次。文章对PACS系统在数字化医院中的建设,首先对PASC系统的发展做出了介绍,然后详细地阐述了PACS系统的设计,最后对我国的数字化医院建设中PACS的应用进行了分析。     

A multipurpose audio watermarking algorithm with synchronization and encryption

We propose a new multipurpose audio watermarking scheme in which two complementary watermarks are used.For audio copyright protection,the watermark data with copyright information or signature are first encrypted by Arnold transformation.Then the watermark data are inserted in the low frequency largest significant discrete cosine transform(DCT) coefficients to obtain robustness performance.For audio authentication,a chaotic signal is inserted in the high frequency insignificant DCT coefficients to detect tampered regions.Furthermore,the synchronization code is embedded in the audio statistical characteristics to resist desynchronization attacks.Experimental results show that our proposed method can not only obtain satisfactory detection and tampered location,but also achieve imperceptibility and robustness to common signal processing attacks,such as cropping,shifting,and time scale modification(TSM).Comparison results show that our method outperforms some existing methods.