In this paper, we propose a scheme for solving the k-mutual exclusion problem in a distributed system, which is a generalization of the quorum based scheme for solving the distributed mutual exclusion problem. The proposed scheme uses a set of weighted quorums as the underlying structure, which can be constructed from any quorum system by applying the technique of k-decomposition. The notion of...

This paper introduces and studies the question of balancing the load on processors participating in a given quorum system. Our proposed measure for the degree of balancing is the ratio between the load on the least frequently referenced element and on the most frequently used one. We give some simple sufficient and necessary conditions for perfect balancing. We then look at the balancing proper...

Among failure-prone and dynamic distributed systems there is a significant class of systems that strive for high availability and can function with inconsistent data. Examples include flight reservation systems which allow overbooking or emergency ambulance systems which return informative responses to time-critical queries. Data replication is a well-known technique for tolerating failures and...

We are going to start a new topic today: Quorum system. The lexical meaning of the word Quorum is “the minimum number of members of a group that needs to be present at any of its meetings to make any decision for the group”. For example, majority is an example of a quorum for voting in a group. Majority is required in the voting system to avoid the partitioning and inconsistency in the decision...

A quorum system is a collection of subsets of nodes, called quorums, with the property that each pair of quorums have a non-empty intersection. Quorum systems are the key mathematical abstraction for ensuring consistency in fault-tolerant and highly available distributed computing. This paper is a brief overview of the evolution of quorum systems, with emphasis on their role in two fundamental ...

A quorum system is a collection of subsets of servers, every two of which intersect. Quorum systems have been suggested as a tool for concurrency control in replicated databases almost twenty years ago. They promised to guarantee strict consistency and to provide high availability and fault-tolerance in the face of server crashes and network partitions. Despite these promises, current commercia...

Disease caused by antibiotic resistant pathogens is becoming a serious problem, both in human and veterinary medicine. The inhibition of quorum sensing, bacterial cell-to-cell communication, is a promising alternative strategy to control disease. In this study, we determined the quorum sensing-disrupting activity of 20 thiophenones towards the quorum sensing model bacterium V. harveyi. In order...

Vibrio fischeri is a typical quorum-sensing bacterium for which lux box, luxR, and luxI have been identified as the key elements involved in quorum sensing. To decode the quorum-sensing mechanism, an artificially constructed cell-cell communication system has been built. In brief, the system expresses several programmed cell-death BioBricks and quorum-sensing genes driven by the promoters lux p...

2007/Jul/02 Sensibility of quorum growth thresholds controlling local immune responses – p. 2007/Jul/02 Sensibility of quorum growth thresholds controlling local immune responses – p. 2/36 Motivation 2007/Jul/02 Sensibility of quorum growth thresholds controlling local immune responses – p. 3/36 Immune system Leukocytes (white blood cells) circulate in the blood Leukocytes are produced in the b...

AI-2-mediated quorum sensing has been identified in various bacteria, including both Gram-negative and Gram-positive species, and numerous phenotypes have been reported to be regulated by this mechanism, using the luxS-mutant strain. But the AI-2 production process confused this regulatory function; some considered this regulation as the result of a metabolic change, which refers to an importan...