In the pipeline banyan (PB), the reservation cycle in the control plane is made several times faster than payload transmission in data plane. This enables pipelining multiple banyans. It is observed that the ratio of throughput to switching delay (service rate) is relatively low in the PB due to the banyan. For this, we present a scalable pipelined asynchronous transfer mode (ATM) switch architecture employing a family of dilated banyan (DB) networks together with their complexity analysis and performance. A DB can be engineered between two extremes: 1) a low-cost banyan with internal and external conflicts, or 2) a highcost conflict-free fully connected network with multiple outlets. Between the two extremes lies a family of DB's having different switching delays and throughputs. Increasing the dilation degree reduces path conflicts, which produces noticeable increase in service rate due to increase in throughput and decrease in path delay. Compared to PB, the pipelined dilated banyan (PDB) requires smaller number of data planes for the same throughput, or provides higher throughput for a given number of data planes. Simulation of PDB is carried out under uniform traffic and simulated ATM traffic. We study the switch performance while varying the load, buffer size, and number of data planes. To analyze the robustness of the switch, we show that performance is not degradable under ATM traffic with temporal and spatial burstiness generated using the ON-OFF model. The PDB is scalable with respect to service rate and can be engineered with respect to: 1) cell loss rate; 2) hardware resources; 3) size of buffers; 4) switching delays; and 5) delay incurred to higher priority traffic. The PDB can deliver up to 3.5 times the service rate of the PB with only linear increase in hardware cost.

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Objective: Assessment of the macular ganglion cells function in myopic subjects using pattern electroretinogram (PERG) in comparison with healthy controls to help in diagnosing of retinal diseases, and studying the relationship of the changes seen in PERG with the axial length (AL) of the eye. Methods: The study was cross sectional, included 62 subjects (121 eyes). Three groups were examined: group 1: controls or emmetropics; group 2: mild myopics; group 3: moderate myopics. For all participants, a detailed pathological story was taken, a comprehensive eye examination was performed, AL was measured, and PERG was recorded, then the variables of the recorded waves (peak time and amplitude) were analyzed. Results: A statistically significant decrease in mean amplitudes of (P50, N95) waves was observed in group 2 (36 eyes) and 3 (25 eyes) compared to group 1 (60 eyes) (P-value <0.01), and a statistically significant elongation of mean N95 peak time was observed in (group 2 and 3) compared to group 1 (P-value <0.01) without being associated with elongation of mean P50 peak time. By studying the relationship between AL and each of peak time and amplitude of (P50, N95) waves, we have found that when AL increased, amplitudes decreased and peak times prolonged in a statistically significant way (P-value <0.01). Conclusion:The decreased amplitude of P50 wave may indicate a functional impairment of the macula in myopic subjects, and the decreased amplitude of N95 wave may be due to a functional impairment of their ganglion cells. The elongation of P50 peak time with increasing of AL may be due to a delay of the synaptic transmission between photoreceptors, bipolar cells, and ganglion cells.

Background: Retinopathy is a severe and common complication of diabetes. The pathology seems to be characterized not only by the involvement of retinal micro vessels but also by a real neuropathy. Before the onset of micro vascular lesions, the retina of the eye undergoes subtle functional changes that are not detectable by fundus photography. Electrophysiological investigations allow a more detailed study of the visual function. These techniques are safe, repeatable, quick, and objective. Objective: To study pattern electroretinogram (PERG) and pattern reversal visual evoked potentials (PRVEP) in type 2 diabetic patients without diabetic retinopathy (DR) or with mild non-proliferative DR (mNPDR) to detect changes by comparing with those of healthy control. And to assess the correlation of the parameters with diabetes duration and the level of Glycosylated Haemoglobin A1c (HbA1c). Materials and Methods: It was a cross-sectional study, included two groups (diabetic patients and the healthy). Age range was preset at 40-65 years. For all the participants, a detailed clinical history was collected, a comprehensive ophthalmic examination and thorough blood investigations were performed, then {PRVEP (60', 15'), PERG} were recorded and (waveform, peak time, amplitude) of tests components were analyzed. Results: Mean (P100, N135) peak times of PRVEP were statistically significantly delayed in (50) eyes of type 2 diabetics without DR when compared to (36) eyes of control (p-value<0.01), abnormalities in waveforms like (double peaks, broad peak) were also observed in diabetics. There were alterations in other parameters (amplitudes of PRVEP, peak times and amplitudes of PERG) but the changes were not statistically significant. No statistically significant changes were found in (6) eyes of diabetic patients with mNPDR. No statistically significant correlation was obtained between diabetes duration or the level of HbA1c and delay of peak times or reduce amplitudes in patients. Conclusions: Electrophysiological tests are sensitive and useful investigations for the early identification of visual dysfunctions before the development of overt retinopathy in type 2 diabetics. PRVEP is more sensitive than PERG to monitor alterations and it may be sufficient to screen the patients in this stage.