多分存彩色图像秘密共享（2，n）方案

文献[2]中提出了一种基于异或（XOR）操作的彩色图像秘密共享（2,n）方案,简单易于实现,但恢复密图的效果较差。通过分析此方案,文章提出一个多分存的彩色图像秘密共享（2,n）方案,通过给用户增加分存图像的方法改善了恢复密图的质量。实验分析表明所提方案不仅取得了很好的恢复效果,而且保持了安全性和算法的简单性。     

Timing and hamming weight attacks on minimal cost encryption scheme

The timing and Hamming weight attacks on the data encryption standard (DES) cryptosystem for minimal cost encryption scheme is presented in this article. In the attack, timing information on encryption processing is used to select and collect effective plaintexts for attack. Then the collected plaintexts are utilized to infer the expanded key differences of the secret key, from which most bits of the expanded secret key are recovered. The remaining bits of the expanded secret key are deduced by the correlations between Hamming weight values of the input of the S-boxes in the first-round. Finally, from the linear relation of the encryption time and the secret key's Hamming weight, the entire 56 bits of the secret key are thoroughly recovered. Using the attack, the minimal cost encryption scheme can be broken with 223 known plaintexts and about 221 calculations at a success rate a＞99%. The attack has lower computing complexity, and the method is more effective than other previous methods.     

Z源逆变器拓扑对比研究

针对传统Z源逆变器存在的一些缺陷,有文献研究了Z源逆变器拓扑的改进问题,目前存在两种改进的Z源逆变器拓扑。其中一种将输入电源插入到Z源网络中,带来的优点是输入电流连续,并可以减小其中一个电容的耐压;另一种输入电源与负载位于同一侧,可以减小Z源电容的电压,并可以实现变换器的软启动。本文在分析改进拓扑稳态工作原理的基础上,对三种拓扑进行了对比分析,并给出了仿真和实验研究的结果,验证了理论分析的正确性。     

Low‐Power 512‐Bit EEPROM Designed for UHF RFID Tag Chip

In this paper, the design of a low‐power 512‐bit synchronous EEPROM for a passive UHF RFID tag chip is presented. We apply low‐power schemes, such as dual power supply voltage (VDD=1.5 V and VDDP=2.5 V), clocked inverter sensing, voltage‐up converter, I/O interface, and Dickson charge pump using Schottky diode. An EEPROM is fabricated with the 0.25 μm EEPROM process. Power dissipation is 32.78 μW in the read cycle and 78.05 μW in the write cycle. The layout size is 449.3 μm × 480.67 μm.     

基于LoRa物联网技术的智能照明控制方案在高速公路上的应用——以北京新机场高速公路(南五环-北京新机场)为例

文章结合北京新机场高速公路照明工程实例,阐述了常规照明控制系统的现状,分析了基于新兴的LoRa物联网技术智能照明控制方案的系统原理和系统构成、系统在高速公路智能照明控制领域的应用以及系统应用能达到的节能和管理效益的提升效果,并对系统的扩展应用前景做了研究分析。     

软件测试模型及其改进方案

当前软件企业面临着用户需求日益复杂、软件产品架构日益扩大等问题。这些问题向软件测试提出了更高的要求。该文对传统测试模型进行了介绍和分析,在分析V模型、W模型以及X模型等软件测试模型的特点和局限性的基础上．利用增加单元测试准则的方法对软件测试模型进行了改进。基于以上工作,以CMMI的标准为指导对软件测试流程以及测试模型的改进提出了思路和方法。     

卫星通信网中ACM技术研究

针对现有卫星通信网传输效率不高的问题,讨论了自适应编码调制(ACM)技术在卫星通信中的应用。提出了在点对点和TDM/TDMA(FDMA)组网方式下的编码调制的自适应调整策略和自适应调整门限值的计算方法,给出了中心站网管控制下的自适应调整流程;并通过重新设计2种应用方式下的调制信号帧结构,结合现有的突发解调技术,可以实现信号的自适应解调。     

轮询多址通信系统门限服务策略研究

从两方面对离散时间情况下轮询多址通信门限排队服务系统进行了研究。改进了系统服务策略，运用嵌入式马尔可夫链理论和多维概率母函数的方法，得到了改进后系统查询时间点处的平均排队队长和信息分组平均时延理论解析式，仿真结果表明分析方法有效且系统性能较之原系统得到提高；采用一种简化的近似算法，得到了轮询周期内平均队长的理论解析式，理论计算与仿真结果有较好的一致性。     

Optimization Design for Digital Binoculars

In order to develop competitive and high performance/cost ratio of digital binoculars, design scheme should be optimized in term of technical capacity, economic benefit, product performance, risk management, etc. The common optimization method is limited in qualitative analysis, and the parameter optimization method is limited in obtaining optimal parameter only from technical side. Each method has its limitation. Based on the analysis of digital binoculars parameters, optional design schemes are laid down.Analytic hierarchy process combined the qualitative analysis with the quantitative analysis together. The design schemes are optimized, and result is worked out.     

海啸带给我们的思考--应急通信的重要性

介绍了应急通信的一般特点,并着重介绍应急通信系统的通信方式和海上安全应急通信系统.