This paper investigates the availability characteristics and the reliability of a three-dissimilar-unit repairable system with two diierent repair facilities. Under some practical assumptions, we obtain the explicit expressions of the state probabilities of the system, and then the explicit expressions of the following performance measures of the system: (1) the pointwise and steady-state avail...

We study the coverage problem from the fault tolerance point of view for sensor networks. Fault tolerance is a critical issue for sensors deployed in places where are not easily replaceable, repairable and rechargeable. The failure of one node should not incapacitate the entire network. We propose three 1 fault tolerant models, and we compare them among themselves, and with the minimal coverage...

Research in traditional reliability theory is based mainly on probist reliability, which uses a binary state assumption and classical reliability distributions. In the present paper the binary state assumption has been replaced by a fuzzy state assumption, thereby leading to profust reliability estimates of a repairable system, which is modeled as a four unit gracefully degradable system using ...

This paper presents a formal framework allowing to extend the simplification of static fault trees to fault trees built with gates PRIORITY AND. The laws which make these simplifications possible have been demonstrated thanks to a homogeneous algebraic definition of each gate studied. These definitions use a mathematical model of events able to take into account their order of appearance. The p...

When a node in a distributed storage system fails, it needs to be promptly repaired to maintain system integrity. While typical erasure codes can provide a significant storage advantage over replication, they suffer from poor repair efficiency. Locally repairable codes (LRCs) tackle this issue by reducing the number of nodes participating in the repair process (locality), with the cost of reduc...

In this paper we study asymptotic behaviour of marked point processes describing failure processes of repairable systems in which repair decisions depend on the past. Under natural conditions on system parameters such processes admit unique time stationary distributions and are ergodic. Convergence of moments and mean number of failures as well as central limit theorems will be established. The...

This paper deals with the modeling of a preventive maintenance strategy applied to a single-unit system subject to random failures. According to this policy, the system is subjected to imperfect periodic preventive maintenance restoring it to ‘as good as new’ with probability p and leaving it at state ‘as bad as old’ with probability q. Imperfect repairs are performed following failures occurri...

Subscapularis is the most powerful muscle in the rotator cuff. A steep learning curve and constrained space anteriorly make the repair difficult. In massive tears of the rotator cuff, repair of the subscapularis initially makes the massive supraspinatus tear repairable. We present our technique to repair subscapularis and supraspinatus tear by double-row anchors in a knotless and tension-free m...

Two related families of codes are studied: batch codes and codes for private information retrieval. These two families can be viewed as natural generalizations of locally repairable codes, which were extensively studied in the context of coding for fault tolerance in distributed data storage systems. Bounds on the parameters of the codes, as well as basic constructions, are presented. Connectio...