Estimation of scanner parameters is an important part in developing electronic document management system. This paper suggests considering the scanner as a system that contains two main channels: a photoelectric conversion channel and a channel for measuring spatial coordinates of objects. Although both of channels consist of the same elements, the testing of their parameters should be executed separately. The special structure of the two-dimensional reference signal is offered for this purpose. In this structure, the fields for testing various parameters of the scanner are sp atially separated. Characteristics of the scanner are associated with the loss of information when a document is digitized. The methods to test grayscale transmitting ability, resolution and aberrations level are offered.

An OMNET package with an implementation of a useful modification of a well-known self-similar traffic model is presented. The package is designed for the analysis of real WAN traffic traces, for the identification of model parameters and for the generation of synthetic traffic, which is close to real one by a number of characteristics simultaneously. These characteristics include traffic value probability distribution, normalized autocorrelation function and Hurst parameter. The performance of the package was tested with traffic traces from CAIDA and Internet Traffic Archive collections. These experiments revealed that the probability distribution of the modern WAN traffic has multimodal “saw-like” form. The reason for that interesting phenomenon is yet to be discovered.

Constant bit rate (CBR) traffic is expected to be an important traffic source in high-speed networks. Such sources usually have stringent delay and loss requirements and in many cases they should be delivered exactly as they were generated. A simple delay priority scheme in the network nodes will bound the delay and delay jitter for CBR traffic so that the CBR flows with stringent QoS will only compete with similar traffic flows within the network. We extend the work of Privalov and Sohraby (see IEEE/ACM Trans. on Networking, 1998) to a networking environment and provide the end-to-end jitter analysis of feed-forward connection-oriented networks supporting multiplexed CBR connections. The impact of the traffic mix in each node and the number of nodes in the network on the end-to-end jitter of individual flows are examined.

Constant bit rate (CBR) traffic is expected to be a major source of traffic in high-speed networks. Such sources may have stringent delay and loss requirements and in many cases, they should be delivered exactly as they were generated. A simple delay priority scheme will bound the cell delay and jitter for CBR streams, so that in the network switches, CBR traffic will only compete with other CBR traffic in the networks. We consider a multiplexor in such an environment. We provide an exact analysis of the jitter process in the homogeneous case. In this case, we obtain the complete characterization of the jitter process showing the inaccuracies of the existing results. Our results indicate that the jitter variance is bounded and never exceeds the constant /sup 2///sub 3/ slot. It is also shown that the per-stream successive cell inter-departures times are negatively correlated with the lag 1 correlation of - 1/2 . Higher order correlation coefficients are shown to be zero. Simple asymptotic results on per-stream behavior are also provided when the number of CBR streams is considered large. In the heterogeneous case, we bound the jitter distribution and moments. Simple results are provided for the computation of the bound on the jitter variance for any mix of CBR streams in this case. It is shown that streams with a low rate (large period) do experience little jitter variance. However, the jitter variance for the high-rate streams could be quite substantial.

Constant bit-rate (CBR) traffic is expected to be a major source of traffic in high-speed networks. Such sources may have stringent delay and loss requirements and, in many cases, they should be delivered exactly as they were generated. A simple delay priority scheme will bound the cell delay and jitter for CBR streams so that in the network switches CBR traffic will only compete with other CBR traffic in the networks, In this paper we consider a multiplexor in such an environment. We provide an exact analysis of the jitter process in the homogeneous case. In this case we obtain the complete characterization of the jitter process showing the inaccuracies of the existing results. Our results indicate that jitter variance is bounded and never exceeds the constant 2/3 slot. It is also shown that the per-stream successive cell interdeparture times are negatively correlated with the lag 1 correlation of -1/2. Higher order correlation coefficients are shown to be zero. Simple asymptotic results on per-stream behavior are also provided when the number of CBR streams is considered large. In the heterogeneous case we bound the jitter distribution and moments. Simple results are provided for the computation of the bound on the jitter variance for any mix of CBR streams in this case. It is shown that streams with a low rate (large period) do experience little jitter variance. However, the jitter variance for the high-rate streams could be quite substantial.