Redundancy technique is known as a way to enhance the reliability and availability of non-reparable systems, but for repairable systems, another factor is getting prominent called as the number of maintenance resources. In this study, availability optimization of series-parallel systems is modelled by using Markovian process by which the number of maintenance resources is located into the obje...

The distribution of extracellular enzyme activities in particle-size fractions of sediments was investigated in a subtropical mangrove ecosystem. Five enzymes involved in carbon (C), nitrogen (N), and phosphorus (P) cycling were analyzed in the sand, silt, and clay of sediments. Among these fractions, the highest activities of phenol oxidase (PHO), β-D glucosidase (GLU), and N-acetyl-glucosimin...

in this paper, we study different methods of solving joint redundancy-availability optimization for series-parallel systems with multi-state components. we analyzed various effective factors on system availability in order to determine the optimum number and version of components in each sub-system and consider the effects of improving failure rates of each component in each sub-system and impr...

The development of cheap computing resources and an efficient networking infrastructure has led to the abundance of large computing clusters. Clusters introduce interesting resource management problems. A significant challenge for a cluster’s resource manager is to dynamically and efficiently allocate resources to competing consumers according to a configurable policy and to provide guarantees ...

As greater numbers of data-intensive applications are required to process big data in bandwidth-constrained datacenters with heterogeneous physical machines (PMs) and virtual machines (VMs), network core traffic is experiencing rapid growth. The VMs of a virtual cluster (VC) must be allocated as compactly as possible to avoid bandwidth-related bottlenecks. Since each PM/switch has a certain fai...

Resource allocation involves deciding how to divide a resource of limited availability among multiple demands in a way that optimizes current objectives. In this brief paper we focus on one type of distributed resource allocation problem where via an imperfect communication network multiple processors can share the load presented by multiple task types. We introduce asynchronous “cooperative” r...

ii Abstract Video servers aimed at the home market must deliver very large files at a low cost. The video files must be shared and reused to contain costs. The nature of videos, however, demand a low jitter (late block delivery) rate. Normal systems tolerate disk queues and deliver, typically, smaller objects in a less predictable manner. This paper explores in a multi disk, stripped, enviornme...

Authentication as a security key issue is required for securing the inter-vehicle communication. Mostly, authentication schemes that depend on the network infrastructure Road Side Unit (RSU) had been proven to have low computation and communication overhead. RSUs may become unavailable due to congestion or failure conditions. Replicating authentication service offered by RSUs to trusted vehicle...

In this paper, we consider the problem of dynamic spectrum allocation in cognitive radio (CR) networks and propose a new sealed-bid auction framework to address the spectrum allocation problem when the spectrum is not available with certainty. In our model, we assume that the moderator plays the dual role of being a fusion center (FC) for spectrum sensing and an auctioneer for spectrum allocati...

An availability model is developed to optimize the availability of a series repairable system with multiple k-out-of-n subsystems in this paper. There are two types of decision variables that determine the system designer’s decision to allocate the number of repairmen and to allocate the number of redundant components in each subsystem in the presence of weight, volume and cost constraint...