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1.
Many recent studies have convincingly demonstrated that network traffic exhibits a noticeable self-similar nature, which has a considerable impact on network performance, and most studies of optical burst switching (OBS) networks are under a fundamental assumption that full wavelength conversion is available throughout the network. In practice, however, economic and technical considerations are likely to dictate a more limited and sparse deployment of wavelength converters in the optical network. Therefore, we present a novel scheme for OBS networks, called logical cascaded private subnet (LCPN) with start wavelength assignment policy. We define the concept of canoe relative to cluster in self-similar traffic, and introduce a new device named payload segregator at the edge node as a gateway to the core node in OBS Networks. According to the changes in the edge node framework, we put forward the concept of cluster private subnet and canoe private subnet in the core node correspondingly. A new start wavelength assignment policy is proposed for the absence of (full) wavelength conversion capabilities in the core node of OBS Networks. The performance study indicates that, our new scheme is robust under self-similar traffic and wavelength continuity constraint.  相似文献   
2.
龚兴华 《世界电信》1994,7(5):46-47
本文以一个多媒体通信应用VISIT为实例,介绍了多媒体通信在数字程控交换机及专网中的应用情况。  相似文献   
3.
为了对全国平均每百户居民私家车拥有量进行预测,建立了可分离变量微分方程的数学模型,采用最小二乘法,借助Excel作为计算工具,得到了微分方程近似解的参数值,并用微分方程的近似解估计了最大拥有量以及2010年以后某些年的拥有量.  相似文献   
4.
建立私有云VPC需将企业内部IT资源与外部服务资源实现互通,而SDN便是实现这一切的关键。  相似文献   
5.
介绍了SOI技术的特点和制造方法、超薄SOI技术,应变硅SOI技术及其设备,如大束流专用氧离子注入机。  相似文献   
6.
A linear quadtree compression scheme for image encryption   总被引:5,自引:0,他引:5  
A private key encryption scheme for a two-dimensional image data is proposed in this work. This scheme is designed on the basis of lossless data compression principle. The proposed scheme is developed to have both data encryption and compression performed simultaneously. For the lossless data compression effect, the quadtree data structure is used to represent the image; for the encryption purpose, various scanning sequences of image data are provided. The scanning sequences comprise a private key for encryption. Twenty four possible combinations of scanning sequences are defined for accessing four quadrants, thereby making available 24n × 4n(n − 1)/2 possibilities to encode an image of resolution 2n × 2n. The security of the proposed encryption scheme therefore relies on the computational infeasibility of an exhaustive search approach. Three images of 512 × 512 pixels are used to verify the feasibility of the proposed scheme. The testing results and analysis demonstrate the characteristics of the proposed scheme. This scheme can be applied for problems of data storage or transmission in a public network.  相似文献   
7.
Lanthanide p-toluene sulphonic acid (ptsa) complexes were prepared for La, Pr, Nd, Sm, Eu, Dy, Ho, Er and Yb, and found to exist as Ln(ptsa)3. Conductivity studies of La(ptsa)3 in DMSO and DMF suggest 1:2 and, possibly, 1:1 electrolyte behaviour in these solvents, respectively. NMR lanthanide-induced chemical shifts (LIS) for aromatic protons in (ptsa)? and methyl protons in DMSO, were measured for all complexes as a function of the [Ln3+[DMSO] in a medium consisting of CCl4, DMSO, and CH3CN. Analysis of the LIS data suggests a change in (ptsa)? coordination round Ln3+ across the lanthanide series.  相似文献   
8.
综合业务局部区域网的发展   总被引:1,自引:0,他引:1  
本文首先说明企业机关单位中数据LAN与电话PABX宜予合并,组成综合业务局部区域网(ISLAN);继而解释建立这种ISLAN应予周密考虑的问题;然后,作为例子,介绍英国电信研究实验室专为ISLAN创拟的Orwell协议,包括分隙环(slotted ring)和并联环(torus),以及它们每一结点和每一线路复接器的结构。这种ISLAN是以异步转移方式(ATM)为依据的,接口码速150-600Mb/s。最后简单表示分布控制ISLAN在大楼的装置应用。  相似文献   
9.
This paper considers the problem of coordinating a single-vendor multi-buyer inventory system when there are privacy restrictions in the information required to solve the problem. The objective function and cost parameters of each facility are regarded as private information that no other facilities in the system have access to. Moreover, each facility is responsible to specify its own replenishment policy. The objective is to minimize the total average setup/ordering and inventory-related cost. Solution methodologies under private and global information are developed to find two types of nested power-of-two stationary policies. The first policy assumes all the buyers must replenish simultaneously. The second policy is a more general case where the common replenishment assumption is relaxed. A simple form of information exchange is uncovered that allows the solution methodologies for private and global information yield the same results. The experimental results suggest that the performance of the proposed heuristics is comparable or better than an existing method.  相似文献   
10.
为了对网络蠕虫等网络攻击行为进行早期检测,论文设计实现了一个基于暗网的可视化的早期检测系统,并采用实际网络实验的方法,在某专用网络中进行实验,结果表明该系统在专用网络中比传统入侵检测系统更早发现蠕虫,且时间提前量十分可观。  相似文献   
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