Software architectural design is essential for complex distributed applications. Architectural specifications need to define the key aspects of the application, including its intended functions, interfaces, interopera...
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Software architectural design is essential for complex distributed applications. Architectural specifications need to define the key aspects of the application, including its intended functions, interfaces, interoperability requirements, distributability; scalability, extensibility, target platforms and networks, and required middleware services. the authors present an architectural extension for specifying distributable components of the application and for quantifying their interaction patterns. the goal of the specification is to serve as the basis for obtaining optimal distributions of the application components over a target network that minimizes remote communication among the components. the optimal distributions are obtained by using the architectural specification to derive a BIP (binary integer programming) model and solving the resulting system. they formalize the object-oriented architectural style using the Z specification language. this style defines the detailed information necessary to derive optimal distributions using the BIP model.
this contribution introduces a class of Galois field used to achieve fast finite field arithmetic which we call an Optimal Extension Field (OEF). this approach is well suited for implementation of public-key cryptosys...
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the authors propose a knowledge representation system that combines a greater expressive richness than that of the Boolean or attribute frameworks, and an analogous treatment complexity. this system can be used in sym...
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the authors propose a knowledge representation system that combines a greater expressive richness than that of the Boolean or attribute frameworks, and an analogous treatment complexity. this system can be used in symbolic-numerical clustering analysis and will be used to build a Galois (concept) lattice. Data and data classes are described by labelled, recursive trees called genterms. the set of these are generated with an algebraic signature. In addition, it is ordered by a generalization relation inducing a semilattice and easily extending to a lattice. Genterm node labels belong to numerical or symbolic sets of type. Each of these sets is a semilattice in which the order relation can also be viewed as a generalization relation. the used formalism is similar to those of abstract data type signatures and offers an alternative to the description logic formalisms. the elements of the Galois lattice between a genterm lattice and a power set of objects are couples (concepts) containing one set of objects and its description by a unique genterm.
Essentially all distributed systems, applications, and services at some level boil down to the problem of managing distributed shared state. Unfortunately, while the problem of managing distributed shared state is sha...
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Essentially all distributed systems, applications, and services at some level boil down to the problem of managing distributed shared state. Unfortunately, while the problem of managing distributed shared state is shared by many applications, there is no common means of managing the data-every application devises its own solution. We have developed Khazana, a distributed service exporting the abstraction of a distributed persistent globally shared store that applications can use to store their shared state. Khazana is responsible for performing many of the common operations needed by distributed applications, including replication, consistency management, fault recovery, access control and location management. Using Khazana as a form of middleware, distributed applications can be quickly developed from corresponding uniprocessor applications through the insertion of Khazana data access and synchronization operations.
We introduce a new performance metric, called Load Balancing Factor (LBF), to assist programmers with evaluating different tuning alternatives. the LBF metric differs from traditional performance metrics since it is i...
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We introduce a new performance metric, called Load Balancing Factor (LBF), to assist programmers with evaluating different tuning alternatives. the LBF metric differs from traditional performance metrics since it is intended to measure the performance implications of a specific tuning alternative rather than quantifying where time is spent in the current version of the program. A second unique aspect of the metric is that it provides guidance about moving work within a distributed or parallel program rather than reducing it. A variation of the LBF metric can also be used to predict the performance impact of changing the underlying network. the LBF metric can be computed incrementally and online during the execution of the program to be tuned. We also present a case study that shows that our metric can predict the actual performance gains accurately for a test suite of six programs.
this paper proposes a transparent selective sequential consistency approach to distributed shared memory (DSM) systems. First, three basic techniques-time selection, processor selection, and data selection-are analyze...
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this paper proposes a transparent selective sequential consistency approach to distributed shared memory (DSM) systems. First, three basic techniques-time selection, processor selection, and data selection-are analyzed for improving the performance of strictly sequential consistency DSM systems, and a transparent approach to achieving these selections is proposed. then, this paper focuses on the protocols and techniques devised to achieve transparent data selection, including a novel selective lazy/eager updates propagation protocol for propagating updates on shared data objects, and the critical region updated pages set scheme to automatically detect the associations between shared data objects and synchronization objects. the proposed approach is able to offer the same potential performance advantages as the entry consistency model or the scope consistency model, but it imposes no extra burden to programmers and never fails to execute programs correctly. the devised protocols and techniques have been implemented and experimented with in the context of the TreadMarks DSM system. Performance results have shown that for many applications, our transparent data selection approach outperforms the lazy release consistency model using a lazy or eager updates propagation protocol.
NYNET (ATM wide area network testbed in New York state) Communication System (NCS) is a multithreaded message passing system developed at Syracase University that provides high performance and flexible communication s...
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NYNET (ATM wide area network testbed in New York state) Communication System (NCS) is a multithreaded message passing system developed at Syracase University that provides high performance and flexible communication services over asynchronous transfer mode (ATM) based high performance distributed computing (HPDC) environments. NCS capitalizes on thread based programming model to overlap computations and communications, and develop a dynamic message passing environment with separate data and control paths. this leads to a flexible and adaptive message passing environment that can support multiple flow control, error control, and multicasting algorithms. We provide an overview of the NCS architecture and present how NCS point to point communication services are implemented. We also analyze the overhead incurred by using multithreading and compare the performance of NCS point to point communication primitives withthose of other message passing systems such as p4, PVM, and MPI. Benchmarking results indicate that NCS shows comparable performance to other systems for small message sizes but outperforms other systems for large message sizes.
Fast remote procedure call (RPC) is a major concern for distributed systems. Many studies aimed at efficient RPC consist of either new implementations of the RPC paradigm or manual optimization of critical sections of...
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Fast remote procedure call (RPC) is a major concern for distributed systems. Many studies aimed at efficient RPC consist of either new implementations of the RPC paradigm or manual optimization of critical sections of the code. this paper presents an experiment that achieves automatic optimization of an existing, commercial RPC implementation, namely the Sun RPC. the optimized Sun RPC is obtained by using an automatic program specializer. It runs up to 1.5 times faster than the original Sun RPC. Close examination of the specialized code does not reveal further optimization opportunities which would lead to significant improvements without major manual restructuring. the contributions of this work are: the optimized code is safely produced by an automatic tool and thus does not entail any additional maintenance; to the best of our knowledge this is the first successful specialization of mature, commercial, representative system code; and the optimized Sun RPC runs significantly faster than the original code.
the proceedings contain 18 papers. the special focus in this conference is on Functional and logicprogramming. the topics include: Safe folding/unfolding with conditional narrowing;optimal non-deterministic functiona...
ISBN:
(纸本)3540634592
the proceedings contain 18 papers. the special focus in this conference is on Functional and logicprogramming. the topics include: Safe folding/unfolding with conditional narrowing;optimal non-deterministic functional logic computations;a semantic basis for termination analysis of logic programs and its realization using symbolic norm constraints;parallelizing functional programs by generalization;higher-order equational unification via explicit substitutions;parameterised higher-order algebraic specifications;a computation model for a higher-order functional logic language;on composable properties of term rewriting systems;needed reductions with context-sensitive rewriting;conditional term graph rewriting;lazy narrowing with parametric order sorted types;termination of algebraic type systems;proof net semantics of proof search computation;perpetuality and uniform normalization;model generation with existentially quantified variables and constraints and optimal left-to-right pattern-matching automata.
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