This paper considers the problem of dynamically establishing dependable connections (D-connections) with specified failure restoration guarantees in wavelength-routed wavelength-division multiplexed (WDM) networks. We call a connection with fault tolerant requirements as a D-connection. We recommend using a pro-active approach to fault tolerance wherein a D-connection is identified with the est...

The data transmission potential inherent in optical networks is enormous, and because of this great potential, optical networks are in dire need of fault toleration. Recently, various fault toleration techniques exploiting the special properties of optical data transmission have been presented, one of the most interesting being backup-multiplexing. Backup multiplexing comes in a couple of diffe...

In distributed data base systems (DDBSs), a transaction blocks during two-phase commit (2PC) processing if the coordinator site fails and at the same time some participant site has declared itself ready to commit the transaction. The blocking phenomena reduces availability of the system since the blocked transactions keep all the resources until they receive the final command from the coordinat...

The present study introduced a novel hierarchical hub set covering problem with capacity constraints. This study showed the significance of fixed charge costs for locating facilities, assigning hub links and designing a productivity network. The proposed model employs mixed integer programming to locate facilities and establish links between nodes according to the travel time between an origin-...

The p-hub center problem is to locate p hubs and to allocate non-hub nodes to hub nodes such that the maximum travel time (or distance) between any origin–destination pair is minimized. We address the p-hub center allocation problem, a subproblem of the location problem, where hub locations are given. We present complexity results and IP formulations for several versions of the problem. We esta...

Storage capacity, like computing power, follows its Moore’s law and grows dramatically. Consequently, the need for data backup services increases. The domain of data backup was recently hit by the peer-to-peer wave: several projects propose to use a cooperative approach to the backup problem. In this paper we survey these projects, the various problems they face and the techniques they propose ...

hub covering location problem, network design,   single machine scheduling, genetic algorithm,   shuffled frog leaping algorithm   hub location problems (hlp) are synthetic optimization problems that appears in telecommunication and transportation networks where nodes send and receive commodities (i.e., data transmissions, passengers transportation, express packages, postal deliveries, etc.) th...

The hierarchical hub location problem is encountered three-level network that is applied in production-distribution system, education system, emergency medical services, telecommunication network, etc. This paper addresses the hierarchical hub covering problem with single assignment accounting for mandatory dispersion of central hubs restriction as a special case. This formulation with incorpor...

We present a trace-driven simulator that evaluates the performance of backup algorithms. We use this simulator to compare the performance of the commonly-used level scheme (our name for the algorithm used by the UNIX dump utility) with that of a new algorithm called the Z scheme. We show that the Z scheme has better backup performance than the level scheme and slightly worse restore performance...