In this paper we consider a wiretap channel with a secret key buffer. We use the coding scheme of [1] to enhance the secrecy rate to the capacity of the main channel, while storing each securely transmitted message in the secret key buffer. We use the oldest secret bits from the buffer to be used as a secret key to transmit a message in a slot and then remove those bits. With this scheme we are...

Continuous Time Markov Chain (CMTC) is widely used to describe and analyze systems in several knowledge areas. Steady state availability is one important analysis that can be made through Markov chain formalism that allows researchers generate equations for several purposes, such as channel capacity estimation in wireless networks as well as system performance estimations. The problem with this...

We consider an infinite graph G whose vertex set is the set of natural numbers and adjacency depends solely on the difference between vertices. We study the largest cardinality of a set of permutations of [n] any pair of which differ somewhere in a pair of adjacent vertices of G and determine it completely in an interesting special case. We give estimates for other cases and compare the results...

There has been criticism of the use of budgeted capacity as the denominator of overhead rates. Prior questionnaire-based research has analysed which type of capacity is used in the denominator of overhead rates, but it has not assessed why these capacity levels are used. This paper uses grounded theory techniques to analyse 50 interviews with British management accountants about why a particula...

Common lean wisdom concerning efficient operations is to reduce variability in workflow throughput. Lean producers use various methods to dissipate production variability in a system that provides wide product variety in order to allow production to better match demand. Amongst these is the use of flexible capacity strategies to adapt to changeable conditions when this approach best suits. Yet,...

Abstract: We develop a model to analyze optimal product-costing and pricing decisions in a dynamic information environment under long-term-capacity commitment. The arrival of new information about demand and cost parameters each period makes the problem complex. The optimal prices and capacity choices in our model cannot be decoupled as in Banker and Hughes’ (1994) single-period model. The opti...

We study the interaction between two interfering Gaussian 2-user multiple access channels. The capacity region is characterized under mixed strong–extremely strong interference and individually very strong interference. Furthermore, the sum capacity is derived under a less restricting definition of very strong interference. Finally, a general upper bound on the sum capacity is provided, which i...

There are several studies analysing the Internet’s topology to obtain insights into the consequences of disturbances. But concentrating on topology misses the point that the Internet’s survivability depends on the relationship of topology, capacity and traffic. Using the INESS simulation model we compare several disturbances of Internet exchange points to reveal the consequences for the surviva...

During recent years, MIMO communication systems become an important research and development subject. Many papers are already published in the fields of channel capacity, synchronization, space time coding, etc. The idea of this book was born during the Wicom Conference in 2007, where many sessions have dedicated to MIMO systems, dealing with physical channel layer as well as protocol aware MIM...