Complex orthogonal designs (CODs) are used to construct space-time block codes. COD Oz with parameter [p, n, k] is a p × n matrix, where nonzero entries are filled by ±zi or ±z ∗ i , i = 1, 2, . . . , k, such that O H z Oz = (|z1| 2 + |z2| 2 + . . . + |zk| 2)In×n. Adams et al. in “The final case of the decoding delay problem for maximum rate complex orthogonal designs,” IEEE Trans. Inf. Theory,...

We study a M/M/1 queue in a multi-phase random environment, where the system occasionally suffers a disastrous failure, causing all present jobs to be lost. The system then moves to a repair phase. As soon as the system is repaired, it moves to phase i with probability qi ≥ 0. We use two methods of analysis to study the probabilistic behaviour of the system in steady state: (i) via probability ...

2-Arylhydrazono-3-oxobutanenitriles 2 was reacted with hydroxylamine hydrochloride to yield amidooxime 3. This was cyclized into the corresponding oxadiazole 4 on refluxing in acetic anhydride. When refluxed in DMF in presence of piperidine, the corresponding 1,2,3-triazoleamine 5 was formed. The latter was acylated to 6 by addition of acetic anhydride while treatment of 5 with malononitrile ga...