Coterie Join Operation and Tree Structured k-Coteries

The coterie join operation proposed by Neilsen and Mizuno produces, from a k-coterie and a coterie, a new k-coterie. For the coterie join operation, this paper first shows 1) a necessary and sufficient condition to produce a nondominated k-coterie (more accurately, a nondominated k-semicoterie satisfying Nonintersection Property) and 2) a sufficient condition to produce a k-conterie with higher availability. By recursively applying the coterie join operation in such a way that the above conditions hold, we define nondominated k-coteries, called tree structured k-coteries, the availabilities of which are thus expected to be very high. This paper then proposes a new k-mutual exclusion algorithm that effectively uses a tree structured k-coterie, by extending Agrawal and El Abbadi's tree algoriyhm. The number of messages necessary for k processes obeying the algorithm to simultaneously enter the critical section is approximately bounded by k log (n / k) in the best case, where n is the number of processes in the system

An asynchronous message-passing distributed algorithm for the global critical section problem

This paper considers the global $(l,k)$-CS problem which is the problem of controlling the system in such a way that, at least $l$ and at most $k$ processes must be in the CS at a time in the network. In this paper, a distributed solution is proposed in the asynchronous message-passing model. Our solution is a versatile composition method of algorithms for $l$-mutual inclusion and $k$-mutual exclusion. Its message complexity is $O(|Q|)$, where $|Q|$ is the maximum size for the quorum of a coterie used by the algorithm, which is typically $|Q| = \sqrt{n}$.Comment: This is a modified version of the conference paper in PDAA201

(h,k)-Arbiters for h-out-of-k mutual exclusion problem

Abstracth-Out-of-k mutual exclusion is a generalization of the 1-mutual exclusion problem, where there are k units of shared resources and each process requests h(1⩽h⩽k) units at the same time. Though k-arbiter has been shown to be a quorum-based solution to this problem, quorums in k-arbiter are much larger than those in the 1-coterie for 1-mutual exclusion. Thus, the algorithm based on k-arbiter needs many messages. This paper introduces the new notion that each request uses different quorums depending on the number of units of its request. Based on the notion, this paper defines two (h,k)-arbiters for h-out-of-k mutual exclusion: a uniform (h,k)-arbiter and a (k+1)-cube (h,k)-arbiter. The quorums in each (h,k)-arbiter are not larger than the ones in the corresponding k-arbiter; consequently, it is more efficient to use (h,k)-arbiters than the k-arbiters. A uniform (h,k)-arbiter is a generalization of the majority coterie for 1-mutual exclusion. A (k+1)-cube (h,k)-arbiter is a generalization of square grid coterie for 1-mutual exclusion

Simulation of Diagonal Data Replication in Mesh

In a large dynamic network, data can be copied anywhere to make it fault tolerant and easy accessed but there must be an efficient protocol to manage the replicas and make sure the data is consistent and high in availability with a low communication cost.In this paper, we introduced a new protocol, named Diagonal Replication in Mesh (DRM) for data replica control protocol for a large dynamic network by using quorum and voting techniques to improve the availability and the communication cost because quorum techniques reduce the number of copies involved in reading or writing data.The protocol of DRM replicates data for large dynamic network by putting the protocol in a logical mesh structure and access consistent data by ensuring the quorum not to have a nonempty intersection quorum.To evaluate our protocol, we developed a simulation model in Java.Our results proved that DRM improves the performance of the response time compare to Three Dimensional Grid structure Protocol (TDGS)

KETERSEDIAAN OPERASI JOIN DIPERLUAS KOTERI-k TAK-TERDOMINASI

Penelitian ini bertujuan menganalisis ketersediaan dari koteri-  mayoritas tak-terdominasi yang menggunakan operasi join diperluas yaitu penggabungkan koteri- ,  dan  masing-masing atas semesta  dan  dengan unsur tereliminasi , dimana  yang menghasilakan koteri-  tak-terdominasi  atas semesta . Metode penggabungan koteri-  mayoritas tak-terdominasi yang menggunakan operasi join diperluas menghasilkan koteri  atas . Hasil ketersediaan dari operasi join kemudian dibandingkan dengan ketersedian dengan menggunakan operasi join. Dari penelitian ini, menunjukkan bahwa ketersedian operasi join memberikan hasil yang lebih baik jika dibandingkan dengan ketersedian dari operasi join

Un protocole contrôle de réplique d'une structure d'arborescence arbitraire. An arbitrary tree-structured replica control protocol

La réplication des données, qui est un problème de calcul distribué, est utilisée dans les grands systèmes distribués, en vue de parvenir à la tolérance aux pannes ainsi que d'améliorer les performances du système. Cependant, des sousjacents protocoles de synchronisation, également connus sous le nom de protocoles contrôle de réplique, sont nécessaires afin de maintenir la cohérence des données entre les répliques. De nombreux protocoles contrôle de réplique existent, chacun ayant ses avantages et inconvénients. Ceux-ci sont mesurés par le coût de communication, la disponibilité ainsi que la charge de système induite par les opérations de lecture ou d'écriture de ces protocoles. En général, ces protocoles contrôle de réplique sont répartis en deux familles: ceux qui supposent que les répliques du système sont organisées logiquement dans une structure et ceux qui ne nécessitent pas d'imposer une structure spécifique aux répliques. Dans cette thèse, à l'équipe ASTRE de l'IRIT (Institut de Recherche en Informatique de Toulouse) et sous la direction du Professeur Jean Paul Bahsoun, nous nous intéressons à l'étudier les protocoles de réplication qui organisent logiquement les répliques dans une structure d'un arbre et étudier la façon de contourner les inconvénients de la racine que ces protocoles en arbre souffrent de son goulot d'étranglement.In large distributed systems, replication is the most widely used approach to offer high data availability, low bandwidth consumption, increased faulttolerance and improved scalability of the overall system. Replication-based systems implement replica control (consistency) protocols that enforce a specified semantics of accessing data. Also, the performance depends on a host of factors chief of which is the protocol used to maintain consistency among the replicas. Several replica control protocols have been described in the literature. They differ according to various parameters such as their communication costs, their ability to tolerate replica failures (also termed as their availability), as well as the load they impose on the system when performing read and write operations. Moreover these replica control protocols can be classified into two families: some protocols assume that replicas of the system are arranged logically into a specific structure (Finite Projective Plane, Grid or Tree) whereas others do not require any specific structure to be imposed on the replicas. In this thesis, at group ASTRE of IRIT and under the supervision of professor Jean-Paul Bashoun, we are interested in studying the replication protocols that arrange logically the replicas into a tree structure and investigate how to circumvent the drawbacks of the root replica as the existing treestructured protocols suffer from the root replica's bottleneck

THE PREDICTORS AND CONSEQUENCES OF INDIVIDUAL VARIATION IN SOCIALITY IN BLACK-TAILED PRAIRIE DOGS (CYNOMYS LUDOVICIANUS)

Sociality describes the organization of members of a species in a group to maximize fitness. It is thought to evolve when the benefits of existing in social groups outweigh the costs. Typically, these costs and benefits are generalized to the species or population level and not at the level of the individual, where the decisions and the consequences of those decisions regarding sociality often resides. Social network analysis (SNA) provides a tool to test hypotheses to identify variation in sociality at an individual level, as well as the potential trade-offs associated with this variation in sociality, which may change across time. In many SNA studies, the temporal variation of the cost/benefit structure is often ignored. Black-tailed prairie dogs (Cynomys ludovicianus) live in highly social colonies and display an elaborate range of social behaviours. Previous research had indicated that individuals live in sub-community structures called coteries, containing one breeding male and a harem of females. The social structure of this species dramatically shifts during the reproductive period. As prairie dogs have this shift in sociality, it is the best time to investigate these potential trade-offs. I constructed social networks of members of a prairie dog colony from the northern limit of their range, in southern Saskatchewan through behavioural observation and examined correlates of variation in sociality between and within individuals (across time). I compared sociality between two seasons that greatly differed in their importance for reproductive success. I determined that better body condition enabled individuals to maintain social stability over time. Furthermore, individual prairie dogs vary their level of sociality over the year, presumably to optimize individual fitness. Reproductive females decrease their sociality during the breeding period to maximize foraging time and availability for defense of their litter, while reproductive males increase their aggressive interactions to defend the home range and resources their coterie females require for foraging. I found that females that maintained affiliative social connections within their own coterie had higher reproductive success than those connecting adjacent coteries, while variation in frequency of agonistic connections did not correlate with reproductive success. This research improves the understanding of the utility of SNA for wild populations through examining acute behavioural shifts and using new temporal methodologies previously unused in wild populations