Standardization of a multi-configuration medium access protocol for broadband ISDN

This paper examines the current work within various standards bodies to define a multi-configuration medium access control (MAC) protocol for operation between broadband ISDN terminals. To begin, the configurations in which the MAC protocol is expected to operate are introduced. The relation between the MAC protocol and the broadband ISDN resource allocation schemes is then discussed. Several MAC protocol proposals currently being discussed in various standards bodies, each with unique assumptions regarding resource allocation in broadband ISDN, are then described and compared. Finally, areas for future work on this topic are identified.     

用于人脸识别的GFC方法

本文介绍了Gabor-fisher classifier分类器(GFC)人脸识别方法,利用该方法首先对面部图像进行Gabor小波处理,再对得到的增广Gabor特征向量应用增强线性辨别法模型(EFM)以得到辨别特征,该方法对于人脸图像在光照和表情变化的情况下仍然是有效的.该方法的新颖之处在于:(1)引入了Gabor小波,得到的增广特征向量更好地反映了图像的特征;(2)应用EFM在对维数进行降低的同时进行分类特征提取.通过与传统的LDA方法和PCA方法的对比得出,该方法在应用于光照和面部表情变化比较大的FERET数据库时,优势比较明显.     

Construction of functional aliphatic polycarbonates for biomedical applications

Aliphatic polycarbonates are one important kind of biodegradable polymers and have been commonly used as integral components of engineered tissues, medical devices and drug delivery systems. As far as the biomedical application is concerned, traditional aliphatic polycarbonates usually suffer from the strong hydrophobicity, deficient functionality, and insufficient compatibility with cell/organs. Consequently, the application is quite limited in scope. Due to the imparted appealing properties, aliphatic polycarbonates bearing specifically designed functional/reactive groups attract great interest from researchers in the recent years. The present review outlines the development up to date concerning the design and biomedical application of functional aliphatic polycarbonates, with an emphasis on their ring-opening (co)polymerization preparation.     

蛋白酶水解铬革屑所得胶原蛋白产物分子量的研究

用经典凝胶柱层析和凝胶电泳相结合的方法 ,对蛋白酶水解铬革屑所得胶原蛋白产物进行了分子量测定 ,并用高效毛细管电泳法进行对比验证。研究表明 :在本文建立的水解条件下 ,水解产物中分子量为5 0 0 0 0 - 70 0 0 0 D之间的占 10 .7%,2 0 0 0 0 - 30 0 0 0 D之间的占 89.3%。     

气体滤光相关红外吸收法测定空气中一氧化碳的测量不确定度评定

建立气体滤光相关红外吸收法(GFC)测定空气中一氧化碳的测量不确定度的评定方法。方法通过建立数学模型,分析各种不确定分量的来源来评定标准不确定度,最后确定合成不确定度和扩展不确定度。     

光声和气体滤波技术相结合的CO探测方法

对火灾中痕量一氧化碳检测不仅可用于燃烧过程分析,产物毒性分析,并且能实现灵敏可靠的火灾探测.但常用的光声仪器的现场性、实时性较差,一般红外吸收法又不如前者灵敏.我们提出一种综合利用光声和CO气体滤波技术进行现场CO检测的方法,保持了吸收光谱法的现场性,又可达到光声方法的灵敏度.     

A multiservice GFC protocol

Generic flow control (GFC) is used to provide controlled transmissions from terminals over the BISDN user-network interface. The reason for requiring controlled transmission is to allow for the multiplexing of cells from a number of terminals connected in either a dual bus or star configuration. GFC must provide fair access for each terminal, and the meaning of this is discussed for different services. It must provide a guaranteed minimum bandwidth, meeting the requirement of fair access for constant bit-rate terminals. It must also provide fair access for variable bit-rate (VBR) terminals. It is proposed that all terminals of a given class are given the same percentage reduction of their agreed peak bandwidths during overload conditions, leading to approximately similar delay distributions within the class. GFC can then be considered as providing a given quality of service per terminal (through guaranteed bandwidth) and an additional common quality of service for the unguaranteed cells. Some simulation results are provided for the dual bus configuration.     

用GFC法研究柠檬酸盐蒙囿铝(Ⅲ)配合物的组成分布

通过凝胶过滤色谱 (GFC)对柠檬酸盐 (Cit)蒙囿的铝 (Ⅲ )配合物溶液的组分进行分离 ,用低压离子色谱(LPIC)和铬天青比色法分别测量各组分中Cit和Al3 +的含量 ,进而对溶液中各组分的分布及各组分中[Al3 +]/[Cit]值进行分析 ,为推断铝配合物的结构和Cit参与配位的方式提供了依据。     

基于GFC的非分散红外CH_4和C_2H_2气体检测系统

基于甲烷气体和乙炔气体近红外吸收的机理,研究了一种高灵敏度非分散红外系统,同时测量甲烷气体和乙炔气体浓度.系统采用折反式吸收池作为气室,结合先进的气体滤波相关技术和相关检测技术,实现了对微弱光谱信号的调制和检测,最后实现对浓度的反演,从而实现了甲烷和乙炔气体实时测量.试验结果表明:系统具有10~(-5)的测量分辨力.     

B-ISDN中用户网路接口处的流量控制分析

以Ｂ－ＩＳＤＮ用户网路接口处的澳式ＧＦＣ规程为中心,在多个终端共享媒介各终端信源采用马氏调制流体模型的情形下,讨论了本规程在对称双点总线结构下的有关ＧＦＣ控制。结果表明：各类端之间的蹁对各类业务终端不构成决定性影响,最终影响各终端带宽分配的决定性因素还是终端的带宽均衡参数β和业务流整形参数γ,因此可以根据各终端的业务质量要求,对β,γ值进行优化选择。