14 research outputs found

    KETERSEDIAAN OPERASI JOIN DIPERLUAS KOTERI-k TAK-TERDOMINASI

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    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

    Method for Constructing Nondominated K-coteries

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    k-coteries for tolerating network 2-Partition

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    Network partition, which makes it impossible for some pairs of precesses to communicate with each other, is one of the most serious network failures. Although the notion of k-coterie is introduced to design a k-mutual exclusion algorithm robust against network failures, the number of processes allowed to simultaneously access the critical section may fatally decrease once network partition occurs. This paper discusses how to construct a k-coterie such that the k-mutual exclusion algorithm adopting it is robust against network 2-partition. To this end, we introduce the notion of complemental k-coterie, and show that complemental k-coteries meet our purpose. We then give methods for constructing complemental k-coteries, and show a necessary and sufficient condition for a k-coteries to be complemental

    OPERASI JOIN KOTERI-k DIPERLUAS

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    Sebagaiman diketahui bahwa koteri-k merupakan perluasan dari definisi koteri yang dapat diterapkan masalah mutex-k. Pada mutex-k terdapat sebanyak k proses yang dapat mengakses sumber daya. Selain itu, kita juga mengenal koteri-k khusus yang disebut dengan koteri-k mayoritas dimana untuk setiap korumnya memiliki ukuran yang sama yang ditentukan dengan . Terdapat beberapa cara dalam penggabungan koter-ki salah satu diantaranya dan sudah tidak asing lagi yaitu operasi join yang merupakan suatu operasi yang digunakan dalam menggabungkan koteri-k mayoritas yang diperkenalkan oleh Neilsen dan Mizuno. Pada operasi join, terdapat salah satu sifat yang menyatakan bahwa jika  dan  tak-terdominasi maka  tak-terdominasi. Ternyata sifat tersebut tidak selamanya berlaku sehingga mengakibatkan koteri-k yang dihasilkan dari operasi join menjadi terdominasi.Tujuan dari penelitian ini yaitu memperkenalkan suatu cara baru dalam menggabungkan koteri-k mayoritas tak-terdominasi yang disebut dengan operasi join diperluas. Dimana operasi join diperluas ini adalah suatu operasi yang dikembangkan dari operasi join yang dibangun dengan cara menggabungkan dua koteri-k mayoritas  dan  yang memiliki ukuran korum yang sama masing-masing atas semesta tak-kosong  dan  dengan unsur tereliminasi , dimana  untuk membentuk  atas semesta tak-kosong . Hasil dari penelitian ini menunjukan bahwa untuk penggabungan dua koteri-k mayoritas tak-terdominasi dengan mengguankan operasi join diperluas akan selalu menghasilkan koteri-k tak-terdominasi dengan nilai k sebelum dan setelah dilakukan operasi penggabungan tidak mengalami perubahan

    Coterie Join Operation and Tree Structured k-Coteries

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    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

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

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    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

    Distributed License Server

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    Efficient Quorum Structure for Distributed Mutual Exclusion

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    Computer Scienc

    Quorum Based Conflict Resolution Algorithms In Distributed Systems

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    Mutual exclusion is one of the most fundamental issues in the study of distributed systems. The problem arises when two or more processes are competing to use a mutual exclusive resource concurrently, i.e., the resource can only be used by at most one process at a time. Synchronizations adopting quorum systems are an important class of distributed algorithms since they are gracefully and significantly tolerate process and communication failures that may lead to network partitioning. Coterie based algorithm is a typical quorum based algorithm for mutual exclusion: A process can use the resource  only if it obtains permissions from all processes in any quorum ofcoterie, and since each quorum intersects with each other and each process only issues one permission, the mutual exclusion can be guaranteed. Many quorum systems have been defined based on the relaxation of the properties of coterie system. Each of them is designed to resolve its corresponding problem, e.g., k-coterie based algorithm to resolve the k-mutual exclusion, local coterie for the generalized mutual exclusion, (h, k)-arbiter for h-out of-k resource allocation problem, etc. Therefore, design an algorithm for any distributed conflict resolution problem is only meant to define a new quorum system which can be implemented to the corresponding problem. Since most of distributed conflict resolution problems are designed based on the relaxation of the safety property of mutual exclusion, understanding the way to relaxing the safety property and its quorum system is important to study any kind of conflict resolution problem in distributed systems
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