基于虚拟MIMO子信道的多用户分集资源调度算法

根据多天线(MIMO)信道空间相关特性,提出一种虚拟子信道的分析方法,从子信道角度探讨信道容量在发射端已知信道响应时预期的性能改善;在此基础上,提出一种逼近信道容量上限的波束形成方法,发掘MIMO信道矩阵最大奇异值与波束形成矢量潜在的联系,并从理论角度详细分析了单用户与多用户最大奇异值联合分布特性,实现阵列增益、空间分集和多用户分集充分融合;仿真与分析表明,利用用户间潜在的随机分布特性能有效提高用户的空间分集增益,提高系统资源利用率,对系统性能改善显著.     

一种新颖的基于混沌映像格子的图像保密通信方案

基于混沌映像格子(CML)提出了一种新颖的图像保密通信方案.发送方利用CML快速产生二值时空混沌序列,并将其与原始图像进行异或加密处理,经通信双方同步后,接收方即可解密出原始图像.由于混沌序列对CMI.中的耦合系数、驱动序列初值等比较敏感,增加了序列抗攻击能力.数值实验结果表明本方案是可行的,并对系统密钥空间、密钥敏感性等密码学特性进行了分析.     

一种基于中断处理机制的动态反汇编算法

传统的反汇编是静态进行的,它难以处理逻辑陷阱、花指令、代码中的数据、动态控制流等问题,这就导致其最终的反汇编结果可能不完整,存在错误.一段特意设计的代码,可以用动态控制流替代静态控制流;一段特意设计的花指令,可以让静态控制流关系任意复杂,这都将使静态反汇编分析难以进行.让代码运行起来,动态地进行反汇编,可以解决上述静态反汇编遇到的问题.结合计算机的中断处理机制,使得代码的实际执行路径是可知的.针对实际执行到的计算机指令进行反汇编,确保了反汇编结果的准确性;反复执行代码,在时间上进行积累,可以确保反汇编结果的完整性不断增加并趋于完整.     

一种新型的HA载药系统药物释放度的测定

目的:设计一种新型的透明质酸(HA)靶向载药系统,为开发治疗卵巢癌的美法仑靶向制剂奠定基础。方法:用活化的聚乙二醇对HA进行修饰后作为载体,与抗肿瘤药美法仑键合形成前药,再自组装成纳米胶束给药系统,并用高效液相法(HPLC)测定药物在模拟人体环境条件下的释药情况。结果:pH值会显著影响药物的累计释放量,P0.05;取样量对给药体系的累计释放量没有显著性影响,P0.05。结论:pH影响透明质酸酶的活性,所以会对药物的释放度带来影响。而取样量的对释放度没有显著性影响。     

基于视差估计算法的多视点视频预测方案

多视点视频编码是立体视频的关键技术,视差估计是目前多视点视频编码中常用的方法之一.探讨了多视点视频编码中的视差估计算法原理,对当前应用视差估计算法的几种典型预测结构进行了深入分析,提出一种结合分级B图与视点相关性的多视点编码方案,该方案在H.264/AVC的编码模型JM下实现.实验表明,该方案在兼顾随机访问性能的同时,实现了较高的编码效率,尤其适合视点间相关性较高的运动图像序列.     

基于VPN技术的组网方案探讨

基于VPN技术,提出了一种为大公司分布在不同区域的分支机构提供一种非常廉价、安全、灵活自如的网络信息传输解决方案,并通过组建试验网络的测试,证明了方案的可行性.     

A Novel Model System for Design of Biomaterials Based on Recombinant Analogs of Spider Silk Proteins

Spider dragline silk possesses impressive mechanical and biochemical properties. It is synthesized by a couple of major ampullate glands in spiders and comprises of two major structural proteins—spidroins 1 and 2. The relationship between structure and mechanical properties of spider silk is not well understood. Here, we modeled the complete process of the spider silk assembly using two new recombinant analogs of spidroins 1 and 2. The artificial genes sequence of the hydrophobic core regions of spidroin 1 and 2 have been designed using computer analysis of existing databases and mathematical modeling. Both proteins were expressed in Pichia pastoris and purified using a cation exchange chromatography. Despite the absence of hydrophilic N- and C-termini, both purified proteins spontaneously formed the nanofibrils and round micelles of about 1 μm in aqueous solutions. The electron microscopy study has revealed the helical structure of a nanofibril with a repeating motif of 40 nm. Using the electrospinning, the thin films with an antiparallel β-sheet structure were produced. In summary, we were able to obtain artificial structures with characteristics that are perspective for further biomedical applications, such as producing three-dimensional matrices for tissue engineering and drug delivery. Vladimir G Bogush and Olga S Sokolova contributed equally to the paper. Name(s) of guarantors of the work: Mikhail P Kirpichnikov, Vladimir G Debabov. Meeting presentation: Russian–American Nanomedicine Workshop, Moscow, 10–12 Dec 2007.     

A Novel System Based on a Poloxamer/ PLGA Blend as a Tetanus Toxoid Delivery Vehicle

Purpose. Previous work on the encapsulation of proteins and antigens in poly(lactic-co-glycolic acid) (PLGA) microspheres has led to the conclusion that microencapsulated antigens are frequently inactivated due to their interaction with the polymer. To improve the compatibility of the antigen with the polymer, we have devised a novel microencapsulated system consisting of a blend of PLGA 50:50 and poloxamer 188 (Pluronic^® F68) and applied it to the delivery of tetanus antigen. Methods. Tetanus toxoid was encapsulated in microspheres containing different amounts of poloxamer using an anhydrous procedure based on an oil-in-oil solvent extraction process. The compatibility of the polymers was studied by Fourier transform infrared (FT-IR) spectroscopy. Microspheres were assayed in vitro and in vivo for their ability to deliver active antigen for extended periods of time. Results. Analysis by FT-IR spectroscopy evidenced the miscibility of both polymers by a hydrogen bonding mechanism. In vitro release studies revealed that microspheres containing poloxamer released anti-genically active TT, in a pulsatile manner, for up to 50 days. In addition, it was observed that the intensity and duration of the pulses were dependent on both poloxamer content and TT loading in the microspheres. The in vivo evaluation of this new system showed that the neutralizing antibodies elicited by the TT encapsulated in poloxamer-PLGA microspheres were considerably higher and more prolonged than those obtained after administration of the aluminum phosphate-adsorbed toxoid. Conclusions. These results indicate the importance of devising new microencapsulation approaches specially adapted for preserving the activity of protein antigens incorporated within PLGA microspheres.     

一种基于词编码的中文文档格式

分析了汉语自动分词问题产生的根源和面临的困难,针对性地提出了一种基于词的中文编码方法和中文文档新格式,实现了以词作为中文文本的最小信息载体,使中文文本分析可以在词平台上实现,避免了自动分词对中文信息处理带来的障碍.基于中文词的编码方法,以每个词作为一个单位,对词进行编码.此方法避开了中文的自动分词问题,特别是解决了歧义切分的难题,并提出了一种利用文档格式解决未登录词问题的新思路.采用统计分析方法对词平台基础上的关键词自动抽取进行了实验研究,取得良好效果.