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Michael Merritt

Other affiliations: Bell Labs, Lawrence Livermore National Laboratory, AT&T  ...read more
Bio: Michael Merritt is an academic researcher from AT&T Labs. The author has contributed to research in topics: Shared memory & Distributed shared memory. The author has an hindex of 33, co-authored 86 publications receiving 6227 citations. Previous affiliations of Michael Merritt include Bell Labs & Lawrence Livermore National Laboratory.


Papers
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Book ChapterDOI
03 Jul 1995
TL;DR: The translation technique generalizes to other interleaving models, although in each case, the translation map must match the specific model, and enables one to verify systems specified by I/O Automata through model-checkers such as COSPAN or SMV, that operate on models with synchronous parallel composition.
Abstract: The I/O Automaton paradigm of Lynch and Tuttle models asynchrony through an interleaving parallel composition and generalizes more common interleaving models based upon message-passing, such as Hoare's CSP. It is not generally recognized that such interleaving models in fact can be viewed as a special cases of synchronous parallel composition, in which components all move in lock-step. Let A be any set of finite-state I/O Automata drawing actions from a fixed finite set containing a subset Δ, In this article we establish a translation T ∶ A → P to a class of ω-automata P closed under a synchronous parallel composition, for which T is monotonic with respect to implementation relative to Δ, and linear with respect to composition. Thus, for A1,..., A m , B1, ..., B n Σ A and A = A1∥ ⋯ ∥A m , B = B1∥ ⋯ ∥B N , if Δ is the set of actions common to both A and B, then A implements B (in the sense of I/O Automata) if and only if the ω-automaton language containment L(T(A1) ⊗ ⋯ ⊗ T(A m )) ⊂ L(T(B1) ⊗ ⋯ ⊗ T(B n )) obtains, where ∥ denotes the interleaving parallel composition on A and ⊗ denotes the synchronous parallel composition on P. For the class P, we use the L-process model of ω-automata. This result enables one to verify systems specified by I/O Automata through model-checkers such as COSPAN or SMV, that operate on models with synchronous parallel composition. The translation technique generalizes to other interleaving models, although in each case, the translation map must match the specific model. Proofs have been eliminated on account of space limitations. A full version (with all proofs) is available upon request.

15 citations

Proceedings ArticleDOI
01 Aug 1985
TL;DR: Using simple protocols, it is shown how to achieve consensus in constant expected time, within a variety of fail-stop and omission failure models, which are based on distributively flipping a coin.

15 citations

Journal ArticleDOI
TL;DR: It is shown that sticky bits are universal in the Byzantine failure model for n ≥ 3t + 1, an improvement over the previous result requiring n ≥ (2t + 2) + 1.
Abstract: We provide efficient constructions and tight bounds for shared memory systems accessed by n processes, up to t of which may exhibit Byzantine failures, in a model previously explored by Malkhi et al. [21]. We show that sticky bits are universal in the Byzantine failure model for n ≥ 3t + 1, an improvement over the previous result requiring n ≥ (2t + 1) (t + 1). Our result follows from a new strong consensus construction that uses sticky bits and tolerates t Byzantine failures among n processes for any n ≥ 3t + 1, the best possible bound on n for strong consensus. We also present tight bounds on the efficiency of implementations of strong consensus objects from sticky bits and similar primitive objects.

15 citations

Journal Article
TL;DR: Four classic problems in concurrent computing when the number of processes which may participate is infinite are explored, and improved bounds for election when participation is required and a new adaptive algorithm for starvation-free mutual exclusion in a model with unbounded concurrency are proposed.
Abstract: We explore four classic problems in concurrent computing (election, mutual exclusion, consensus, and naming) when the number of processes which may participate is infinite. Partial information about the number of actually participating processes and the concurrency level is shown to affect the possibility and complexity of solving these problems. We survey and generalize work carried out in models with finite bounds on the number of processes, and prove several new results. These include improved bounds for election when participation is required and a new adaptive algorithm for starvation-free mutual exclusion in a model with unbounded concurrency. We also explore models where objects stronger than atomic registers, such as test&set bits, semaphores or read-modify-write registers, are used.

14 citations

Book ChapterDOI
Yehuda Afek1, Danny Dolev2, Eli Gafni1, Michael Merritt3, Nir Shavit2 
24 Sep 1990
TL;DR: This paper presents a solution to the first-in, first out l-exclusion problem of [FLBB79], this solution is achieved without the use of powerful readmodify-write synchronization primitives, and it requires only bounded size shared memory.
Abstract: This paper presents a solution to the first-in, first out l-exclusion problem of [FLBB79]. Unlike the solution in [FLBB79], this solution is achieved without the use of powerful readmodify-write synchronization primitives, and it requires only bounded size shared memory. Moreover, this solution has the extra property of being first-in, first-enabled, a property which subsumes first-in, first-out. Use of the concurrent time-stamp system of [DS89] is key in solving the problem within bounded size shared memory.

14 citations


Cited by
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Patent
30 Sep 2010
TL;DR: In this article, the authors proposed a secure content distribution method for a configurable general-purpose electronic commercial transaction/distribution control system, which includes a process for encapsulating digital information in one or more digital containers, a process of encrypting at least a portion of digital information, a protocol for associating at least partially secure control information for managing interactions with encrypted digital information and/or digital container, and a process that delivering one or multiple digital containers to a digital information user.
Abstract: PROBLEM TO BE SOLVED: To solve the problem, wherein it is impossible for an electronic content information provider to provide commercially secure and effective method, for a configurable general-purpose electronic commercial transaction/distribution control system. SOLUTION: In this system, having at least one protected processing environment for safely controlling at least one portion of decoding of digital information, a secure content distribution method comprises a process for encapsulating digital information in one or more digital containers; a process for encrypting at least a portion of digital information; a process for associating at least partially secure control information for managing interactions with encrypted digital information and/or digital container; a process for delivering one or more digital containers to a digital information user; and a process for using a protected processing environment, for safely controlling at least a portion of the decoding of the digital information. COPYRIGHT: (C)2006,JPO&NCIPI

7,643 citations

Journal ArticleDOI
TL;DR: In this paper, it is shown that every protocol for this problem has the possibility of nontermination, even with only one faulty process.
Abstract: The consensus problem involves an asynchronous system of processes, some of which may be unreliable The problem is for the reliable processes to agree on a binary value In this paper, it is shown that every protocol for this problem has the possibility of nontermination, even with only one faulty process By way of contrast, solutions are known for the synchronous case, the “Byzantine Generals” problem

4,389 citations

Book
01 Jan 1996
TL;DR: This book familiarizes readers with important problems, algorithms, and impossibility results in the area, and teaches readers how to reason carefully about distributed algorithms-to model them formally, devise precise specifications for their required behavior, prove their correctness, and evaluate their performance with realistic measures.
Abstract: In Distributed Algorithms, Nancy Lynch provides a blueprint for designing, implementing, and analyzing distributed algorithms. She directs her book at a wide audience, including students, programmers, system designers, and researchers. Distributed Algorithms contains the most significant algorithms and impossibility results in the area, all in a simple automata-theoretic setting. The algorithms are proved correct, and their complexity is analyzed according to precisely defined complexity measures. The problems covered include resource allocation, communication, consensus among distributed processes, data consistency, deadlock detection, leader election, global snapshots, and many others. The material is organized according to the system model-first by the timing model and then by the interprocess communication mechanism. The material on system models is isolated in separate chapters for easy reference. The presentation is completely rigorous, yet is intuitive enough for immediate comprehension. This book familiarizes readers with important problems, algorithms, and impossibility results in the area: readers can then recognize the problems when they arise in practice, apply the algorithms to solve them, and use the impossibility results to determine whether problems are unsolvable. The book also provides readers with the basic mathematical tools for designing new algorithms and proving new impossibility results. In addition, it teaches readers how to reason carefully about distributed algorithms-to model them formally, devise precise specifications for their required behavior, prove their correctness, and evaluate their performance with realistic measures. Table of Contents 1 Introduction 2 Modelling I; Synchronous Network Model 3 Leader Election in a Synchronous Ring 4 Algorithms in General Synchronous Networks 5 Distributed Consensus with Link Failures 6 Distributed Consensus with Process Failures 7 More Consensus Problems 8 Modelling II: Asynchronous System Model 9 Modelling III: Asynchronous Shared Memory Model 10 Mutual Exclusion 11 Resource Allocation 12 Consensus 13 Atomic Objects 14 Modelling IV: Asynchronous Network Model 15 Basic Asynchronous Network Algorithms 16 Synchronizers 17 Shared Memory versus Networks 18 Logical Time 19 Global Snapshots and Stable Properties 20 Network Resource Allocation 21 Asynchronous Networks with Process Failures 22 Data Link Protocols 23 Partially Synchronous System Models 24 Mutual Exclusion with Partial Synchrony 25 Consensus with Partial Synchrony

4,340 citations

Proceedings ArticleDOI
16 Jul 2001
TL;DR: A suite of security building blocks optimized for resource-constrained environments and wireless communication, and shows that they are practical even on minimal hardware: the performance of the protocol suite easily matches the data rate of the network.
Abstract: As sensor networks edge closer towards wide-spread deployment, security issues become a central concern. So far, much research has focused on making sensor networks feasible and useful, and has not concentrated on security.We present a suite of security building blocks optimized for resource-constrained environments and wireless communication. SPINS has two secure building blocks: SNEP and mTESLA SNEP provides the following important baseline security primitives: Data confidentiality, two-party data authentication, and data freshness. A particularly hard problem is to provide efficient broadcast authentication, which is an important mechanism for sensor networks. mTESLA is a new protocol which provides authenticated broadcast for severely resource-constrained environments. We implemented the above protocols, and show that they are practical even on minimal hardware: the performance of the protocol suite easily matches the data rate of our network. Additionally, we demonstrate that the suite can be used for building higher level protocols.

2,703 citations

Journal ArticleDOI
TL;DR: This paper describes the beliefs of trustworthy parties involved in authentication protocols and the evolution of these beliefs as a consequence of communication, and gives the results of the analysis of four published protocols.
Abstract: Authentication protocols are the basis of security in many distributed systems, and it is therefore essential to ensure that these protocols function correctly. Unfortunately, their design has been extremely error prone. Most of the protocols found in the literature contain redundancies or security flaws. A simple logic has allowed us to describe the beliefs of trustworthy parties involved in authentication protocols and the evolution of these beliefs as a consequence of communication. We have been able to explain a variety of authentication protocols formally, to discover subtleties and errors in them, and to suggest improvements. In this paper we present the logic and then give the results of our analysis of four published protocols, chosen either because of their practical importance or because they serve to illustrate our method.

2,638 citations