On design of physical random access channel in high-speed railway LTE systems

For the uplink in the long-term evolution （LTE） systems, the physical random access channel （PRACH） adopts Zadoff-Chu （ZC） sequences as preamble sequences, and each user can choose a unique cyclic shift for user identification. In high-mobility scenario, the Doppler fre- quency shift raises up the false alarm probability by inducing the correlation peak offsetting at the receiver side. Traditional detection method utilizes multiple search win- dows for searching the potential uplink users. When the Doppler frequency shift is larger than the subcarrier spac- ing, the energy of correlation peak leaks outside the search window and increases the false alarm probability. In this paper, we present a novel design for PRACH preamble sequence for high-speed railway scenario. Through numerical observation, we find out that the offset of the correlation peaks only depends on the initial root sequence number and the length of ZC sequences. Therefore, the root number of ZC sequences should be carefully designed to generate a preamble sequence to fight against the Doppler frequency shift. Consequently, those offsets of the corre- lation peaks are concentrated within a single search win- dow, resulting in lower complexity of detection and lower probability of false alarm for random access in LTE uplink.     

Stable silver nanoparticles–aptamer bioconjugates for cellular prion protein imaging

Combining the unique optical properties of metal nanoparticles and the specific recognition of aptamer,aptamer–nanoparticle conjugates have been extensively used in a wide range of applications,particularly multifunctional nanoparticles for cell detection and molecular imaging.Conventional conjugates prepared by chemisorption of monothiol-modified oligonucleotides onto nanoparticle surfaces suffer from a lack of stability when exposed to a variety of small molecules.If silver is used in place of gold,then this lack of stability is even more pronounced.In this study,we reported here the effective and facile strategy of preparing stable silver nanoparticle–aptamer conjugates by in situ generation of strong metal affinity capping ligands,dithiocarbamates modified anti-prion protein aptamer.The conjugates produced are stable and can withstand NaCl concentration at0.25 mol/L.Meanwhile,they could be applied in the cellular prion protein imaging successfully.     

基于混成自动机的CPS行为建模与属性验证

系统实时性、安全性和可靠性等非功能属性是信息物理系统在诸多领域应用的关键因素。论文在分析CPS模型构建与分析验证中面临的挑战的基础上,提出了一种CPS行为建模与属性验证方法。该方法首先基于混成自动机对CPS的行为进行建模,然后将此模型转换为混合程序模型,最后在定理证明器KeYmaera中对HP模型的属性进行形式化验证。文中论述了行为模型描述语言的结构,建立了混成自动机模型与HP模型之间的转换规则,分析了模型转换的一致性。应用实例表明:该方法既能简单直观地描述CPS动态行为,又能对CPS的属性进行严格的形式化验证,且有效避免了形式化验证中的状态空间爆炸问题。     

13-Bit多速正六边形格子气自动机模型

建立了具完全对称性的多速正六边形格子气自动机模型,通过对典型绕流问题的计算模拟,证明了模型的正确性和有效性。     

d维自助式类渗流细胞自动机模型临界值为零的一个充分条件

研究了d维自助式类渗流细胞自动机模型的临界值问题．对于一类控制定向模型且被修正基本模型控制的自助式渗流模型,利用外生成思想,得到其临界值pc＝0的一个充分条件．     

互连网络诊断性与容错性的细胞图自动机算法的串行模拟

本文对作者以前提出的细胞图自动机算法,给出了串行模拟结果,特别地给出了这些串行模拟程序对几种重要的互连网络如超立方体,交叉立体和Ｍｏｂｉｕｓ立方体模拟的一些具体结果及效率分析．     

基于元胞自动机的企业生产过程的研究

为减少和预防企业生产中意外事故的发生,将元胞自动机理论应用于企业生产过程的研究,建立了某企业生产中基层-员工执行系统的元胞自动机模型.通过对安全生产的个人因素和环境因素在不同状态下的模拟和分析,认为员工遵守规章规程的程度是影响企业安全生产的关键因素之一;并在此基础上,建议企业多关注于如何保证政策法规被规范执行,以缩小实际操作与规则规程之间的差距.这为企业安全生产的研究提供了一种新的思路.     

模拟材料损伤的移动元胞自动机法

根据非均匀材料的细观特征,从质点运动学出发,建立了描述细观非均匀材料破坏的移动元胞自动机(Movable Cellular Automata)法的动力学动基本模型,根据弹塑性小变形理论对元胞对的运动和受力进行分析,建立移动元胞自动机法的本构模型。利用此模型计算了非均匀ZrO2陶瓷材料在冲击载荷下的破坏和断裂过程,得出模拟试样的应力应变曲线。     

量子自动机的格同态

给出了量子自动机的格上同态、子格、理想、同构嵌入的定义,并且研究了量子自动机的格上同态、子格、理想的性质,同时讨论了量子自动机的格上子格、理想与同态之间的关系,得出了量子自动机的格的一些性质.     

二元离散细胞神经网络周期解的存在性

利用Lyapunov函数和Lasalle不变集原理讨论了二元离散细胞神经网络模型,得出了系统存在2-周期解.