Sharif Digital Repository

Network reliability analysis is usually based on minimal path or cut enumeration from which the associated reliability expressions are deduced. The cut-set method is a popular approach in the reliability analysis of many systems from simple to complex configurations. The computational requirements necessary to determine the minimal cut-sets of a network depend mainly on the number of minimal paths between the source and the sink. A technique designated as the "Path Tracing Algorithm" is presented in this paper, which can handle both simple and complex networks, and considers both unidirectional and bi-directional branches. A step by step procedure is explained using a bridge-network. The... 

In a stochastic-flow network, a (d, T, b, P1, P2)-MP is a system state vector for which d units of flow can be transmitted through two separate minimal paths (SMPs) P1 and P2 simultaneously from a source node to a sink node satisfying time and budget limitations T and b, respectively. Problem of determining all the (d, T, b, P1, P2)-MPs, termed as the (d, T, b, P1, P2)-MP problem, has been attractive in reliability theory. Here, some new results are established for the problem. Using these results, a new algorithm is developed to find all the (d, T, b, P1, P2)-MPs, and its correctness is established. The algorithm is compared with a recently proposed one to show the practical efficiency of... 

In recent decades, multistate two-terminal reliability problem has attracted several researchers, and accordingly many exact and approximation approaches have been proposed in the literature in terms of minimal cuts (MCs) or minimal paths (MPs) to address this problem. Here, an MP-based approximation approach is developed based on exact algorithms. With all the MPs at hand, the approach rearranges the MPs ascendingly with respect to their lengths and then sets the flow on some MPs to be zero which turns to reduce the computing cost in solving the problem. We provide the complexity results, and by employing some benchmarks and one thousand randomly generated networks illustrate that not only... 

Abstract Several researchers have worked on transmitting a given amount of flow through a network flow within fastest possible time, allowing flow to be transmitted through one or more paths. Extending this problem to the system reliability problem, the quickest path reliability problem has been introduced. The problem evaluates the probability of transmitting some given amount of flow from a source node to a sink node through a single minimal path in a stochastic-flow network within some specified units of time. Later, the problem has been extended to allow flow to be transmitted through two or more separate minimal paths (SMPs). Here, we consider the problem of sending flow through two... 

In this paper, minimal paths and cuts technique is developed to handle fault tree analysis (FTA) on the critical components of industrial robots. This analysis is integrated with the reliability block diagram (RBD) approach in order to investigate the robot system reliability. The model is implemented in a complex advanced manufacturing system having autonomous guided vehicles (AGVs) as material handling devices. FTA grants cause and effects and hierarchical properties to the model. On the other hand, RBD simplifies the complex system of the AGVs for reliability evaluation. The results show that due to the filtering of the paths in a manufacturing system for AGVs, the reliability is highly... 

The quickest path reliability problem evaluates the probability of transmitting some given units of flow from a source node to a sink node through a single minimal path in a stochastic-flow network within some specified units of time. This problem has been recently extended to the case of transmitting flow through q separate minimal paths (SMPs) simultaneously within a budget constraint. Here, we propose a new algorithm to solve such problems. The algorithm finds all the minimal vectors for which a given demand level d units of flow can be transmitted through q SMPs from a source node to a sink node satisfying some given time and budget limits. In our proposed algorithm, a special... 

We propose a partially adaptive fault-tolerant and deadlock-free routing algorithm in n-dimensional meshes based on the fault-tolerant planar-adaptive routing and Duato's protocol. In particular, we show that only four virtual channels per physical channel are sufficient for tolerating multiple faulty regions even in the case of n-dimensional meshes. Our scheme is able to handle faulty blocks whose associated fault rings have overlaps. In addition, it can be used to route messages when fault regions touch the boundaries of the mesh. A flag bit is introduced for guiding misrouted messages. Messages are routed adaptively in healthy regions of the network. Once a message faces a faulty region,...