Chaotic cryptology

A method to transfer secret information using chaotic dynamical systems is proposed. It is based on modulating a chaotic system with the message such that its time evolution contains the hidden information. Decryption of the cipher is achieved by chaos control. Operation of the scheme is demonstrated by en- and decoding a short german text.     

Cascading attack on trusted-relay quantum key distribution networks

Trusted relays are the main state-of-the-art way to realize quantum key distribution networks.However, it is hard to require that all nodes in the network are fully trusted. In a multipath keytransmission mechanism, the nodes can be weakly trusted because the secret key can be split into many parts and each part is transmitted to the receiver through a different path. However, if the capacity of a node's quantum key pool is poorly designed, an attacker, Eve may eavesdrop on the communicating parties' secret message by initiating a redirection attack. In this paper, we show that Eve can trigger a cascading collapse effect by collapsing one of the edges in the network and forcing the communication parties to transmit the message through the nodes controlled by Eve. The influence of the traffic transfer ratio and the control parameters of the edge load on the breakdown probability of the edge are analyzed using a simulation. In order to effectively defend against the cascading attack, it is important for the designer to handle the relationship between the traffic and the capacity of the quantum key pool of each node in the network.     

Soft Interference Cancellation for Random Coding in Massive Gaussian Multiple-Access

In 2017, Polyanskiy showed that the trade-off between power and bandwidth efficiency for massive Gaussian random access is governed by two fundamentally different regimes: low power and high power. For both regimes, tight performance bounds were found by Zadik et al., in 2019. This work utilizes recent results on the exact block error probability of Gaussian random codes in additive white Gaussian noise to propose practical methods based on iterative soft decoding to closely approach these bounds. In the low power regime, this work finds that orthogonal random codes can be applied directly. In the high power regime, a more sophisticated effort is needed. This work shows that power-profile optimization by means of linear programming, as pioneered by Caire et al. in 2001, is a promising strategy to apply. The proposed combination of orthogonal random coding and iterative soft decoding even outperforms the existence bounds of Zadik et al. in the low power regime and is very close to the non-existence bounds for message lengths around 100 and above. Finally, the approach of power optimization by linear programming proposed for the high power regime is found to benefit from power imbalances due to fading which makes it even more attractive for typical mobile radio channels.     

协作通信系统中的一种高效分集传输技术

研究协作通信系统中结合空时分组码与频域均衡的传输方案,采用判决反馈与干扰抵消等算法对该方案进行优化. 中继节点对发射信号进行空时分组编码后发送,接收机将收到的信号做快速傅里叶变换处理,再进行空间-频域的联合均衡,最后变换回时域判决,即可得到发送信息的估计结果. 该方案可获取中继提供的协作分集增益,且频域处理复杂度很低. 本文通过判决反馈和干扰抵消等信号处理手段降低均衡过程带来的信噪比损失,提高了该算法在协作通信信道下的传输性能,计算机仿真结果表明,当信噪比为12 dB时,新算法可将原算法的误码率从10-2以上降低到10-3以下.      

再论建筑物区分所有权之成员权的性质--评《物权法》第七十条之规定

德国学者贝尔曼先生提出的建筑物区分所有权制度,早在奴隶社会就已萌芽并逐步发展。作为区分所有权人享有的一项特殊权利———成员权,其在学界及实务界受到广泛的关注并逐步为世界各国立法所确认。我国《物权法》亦对此作出了规定———即区分所有权人享有共同管理权。成员权作为一项特殊的权利,其除具有“物法性”的一面,还具有“人法性”的一面,我国立法中将其表述为共同管理权,恰恰忽略了成员权这一重要法律特质,存有不足之处,在理论与实务中均值得进一步探讨。     

船用VHF通信设备的仿真与实操评估

阐述了开发甚高频(very high frequency,VHF)仿真设备所使用的关键技术、系统结构、模块设计、开发流程以及实操评估功能的实现等.系统的实操评估采用分步评估法和层次分析法相结合,根据试题的特点确定各评估要素的权重,并依据评估要素,从任务是否完成,操纵时间和操纵步骤3点来设计评估算法,从而计算出船员的评估成绩.该仿真设备基于Microsoft Visual 2010开发工具和微软基础类库(microsoft foundation classes,MFC)开发环境,实现了对船用VHF通信设备的模拟和实操自动评估功能,用户可以通过客户终端对设备操作进行训练并得到评估成绩.     

分层异构网下的虚拟协作MIMO-STC编码研究

针对移动通信系统中,各单天线用户终端在协作过程中存在的由于用户个数动态变化而导致协作通信无法进行有效空时编码的问题,提出一种新的基于分层异构网络上的不同层之间的协作虚拟多输入多输出空时编码方案(multiple input multiple output space-time coding,MIMO-STC),即由多用户环境中的单天线移动终端共享彼此天线构成一个虚拟多发多收天线阵列,并结合线性弥散空时码编码理论,实现不同层用户簇间的可靠通信.该编码方案能够根据发送簇和接收簇中协作用户个数的具体情况灵活编码,提高分集增益和误码性能.仿真结果表明:采用弥散空时编码方案的虚拟协作通信系统能够有效对抗Raleigh信道下的多径衰落效应,提高系统性能.     

中职本科生计算机人才培养模式研究与探索

利用案例分析和文献分析等方法,以CDIO模式、BTEC模式和结构功能理论为理论基础,从中职本科计算机专业学生缺乏学习信心、自主学习能力以及不适应高校授课方式三方面入手,充分了解中职本学生在学习中面对的困境,并得出学习困境原因;通过创新教育教学方法、完善培养机制、打造双师型师资团队、贯彻"学生本位"的课程设置,充分激活学生学习动力,增加学生内在信心,形成适用于中职本计算机人才的人才培养模式,以提升中职本科计算机人才综合能力为着力点,提高就业能力,满足社会需求.     

一种基于粗交流的博弈分类方法

关于博弈的分类,是博弈论研究的基础性工作。传统博弈论关于博弈的分类实际上只考虑了两个分类准则,分别记为信息的完全性和信息的动态特征。于是,传统博弈论得出了关于博弈的如下分类： Game/(θ1∩θ2)=(完全信息静态博弈,完全信息动态博弈,不完全信息静态博弈,不完全信息动态博弈)。本文在此基础上引入关于博弈分类的第三个分类准则：信息粗交流准则,记为=信息交流的粗糙度。由此,我们得到关于博弈的如下分类：Game/(θ1∩θ2∩θ3)=(完全信息静态博弈,完全信息动态博弈,完全信息粗交流静态博弈,完全信息粗交流动态博弈,不完全信息静态博弈,不完全信息动态博弈,不完全信息粗交流静态博弈,不完全信息粗交流动态博弈)     

Four-Wave Mixing in Microwires to All-Optical Signal Processing in Mode-Division Multiplexing Systems

Abstract

Mode-division multiplexing requires all-optical signal processing techniques that are able to deal with a new coding dimension, the spatial mode. In this context, optical microwires emerge as a potential highly non-linear and multi-modal waveguide envisioning the development of all-optical signal processing devices to mode-division multiplexing systems based on the four-wave mixing process. The inter- and intramodal phase-matching conditions for the four-wave mixing process are mapped as a function of the microwire diameter and the wavelength of signals. Moreover, the efficiency of four-wave mixing considering a strong guiding regime is investigated in the multi-modal regime.