Encoded video streams present numerous problems in bandwidth allocation, multi-plexing and admission control as a result of their Variable Bit Rate(VBR) characteristics. In particular, since video signals show a large range of variability, peak rate allocation results in very low bandwidth utilization. However, other allocation schemes tend to cause cell loss, delay and delay jitter which make ...

The multiple access control (MAC) problem in a wireless network has intrigued researchers for years. For a broad-band wireless network such as wireless ATM, an effective MAC protocol is very much desired because efficient allocation of channel bandwidth is imperative in accommodating a large user population with satisfactory quality of service. Indeed, MAC protocols for a wireless ATM network i...

To guarantee quality of service (QoS), the requirements of video transmission, such as delay and cell loss rate (CLR), are very stringent. These constraints are diicult to meet if high network utilization is desired. In this paper, dynamic band-width allocation algorithms, in which scene change identiication is incorporated, are proposed to improve the bandwidth utilization. The bandwidth alloc...

System NP Hardness problem is addressed and Mathematical framework is proposed for certificates and enhancement of security systems KeywordsKey Management, Certificates, NP

An encoded video traac is a correlated and bursty traac with high value of peak to mean ratio (burstiness). For asynchronous transfer mode (ATM) networks, the challenge of QoS guarantees is to allocate an eeective bandwidth for each video connection and a tradeoo should be achieved between improving the network utilisation and providing QoS guarantees. The allocated bandwidth could be based on ...

In this paper, we propose a new dynamic resource allocation and call admission control method for the VBR video sources to meet the user’s quality of service requirements and at the same time to achieve an efficient resource management in networks. Without any prior knowledge of the user’s traffic statistics, the proposed mechanism dynamically adjusts the necessary bandwidth by the networks bas...

Spaceborne reflectance measurements from the POLDER instrument are used to study the specific directional signature close to the backscatter direction. The data analysis makes it possible to derive the extinction-tobackscatter ratio (EBR), which is related to the inverse of the scattering phase function for an angle of 180 and is needed for a quantitative interpretation of lidar observations (a...

In order to ensure continued availability of high-performance network for the nation's research and education community and to continue supporting the development of new high performance Internet capabilities, the National Science Foundation (NSF) established the very-high-speed Backbone Network Service (vBNS) through a cooperative agreement with MCI telecommunications Corporation. To ensure qu...

introduction: timeliness has been considered as a key domain in quality of emergency department (ed) care and delay in care providing is influential determinants of patient’s outcomes. the present study, aimed to evaluate the determinants of prolonged ed length of stay (los). methods: in this cross-sectional study, using adopted version of the latest form for external evaluation and accreditati...

introduction: due to the use of information technology in libraries and information centers, librarians are faced with many challenges in terms of their roles and needs; hence, they require continuous training to cope with these challenges. the aim of the present study was to determine the effectiveness of in-service training courses for librarians working in libraries at the isfahan university...