Existence conditions are given for maximum likelihood parameter estimates for several commonly employed twoparameter software reliability models. For these models, the maximum likelihood equations can be expressed in ...
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The replication scheme of a distributed database determines how many replicas of each object are created, and to which processors these replicas are allocated. This scheme critically affects the performance of a distr...
Existence conditions are given for maximum likelihood parameter estimates for several commonly employed two-parameter software reliability models. For these models, the maximum likelihood equations can be expressed in...
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Existence conditions are given for maximum likelihood parameter estimates for several commonly employed two-parameter software reliability models. For these models, the maximum likelihood equations can be expressed in terms of a single equation in one unknown. Bounds are given on solutions to these single equations problems to serve as initial intervals for search algorithms like bisection. Uniqueness of the solutions is established in some cases. Results are given for the case of grouped failure data.< >
A tasking query language (TQL) for aiding very general analysis of Ada tasking in a Petri-net-based environment is discussed. An important principle of TQL's design is that of hiding the formalism upon which the a...
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A tasking query language (TQL) for aiding very general analysis of Ada tasking in a Petri-net-based environment is discussed. An important principle of TQL's design is that of hiding the formalism upon which the analysis framework is built. Instead, TQL defines a language by which queries of Ada interactions themselves can be expressed. Examples of TQL's capabilities are presented, and a sample analysis session using the gas station program is described.< >
A method for automating the search for codes that have particular structural features is described. A pattern language is used to specify the pattern of desired code. The benefits of using a pattern language include a...
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A method for automating the search for codes that have particular structural features is described. A pattern language is used to specify the pattern of desired code. The benefits of using a pattern language include a higher level of abstraction in specifying patterns and the power to specify complex patterns which are impossible to express in grep type languages. A system that accepts these patterns and locates code fragments in C source files is described.< >
The replication scheme of a distributed database determines how many replicas of each object are created, and to which processors these replicas are allocated. This scheme critically affects the performance of a distr...
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The replication scheme of a distributed database determines how many replicas of each object are created, and to which processors these replicas are allocated. This scheme critically affects the performance of a distributed system, since reading an object locally is less costly than reading it from a remote processor. Therefore in a read-intensive network a widely distributed replication is mandated. On the other hand, an update of an object is usually written to all, or a majority of the replicas, and therefore in a write-intensive network a narrowly distributed replication is mandated. In other words, the optimal replication scheme depends on the read-write pattern for each object. The authors propose a practical algorithm, called dynamic-data-allocation (DDA), that changes the replication scheme of an object (i.e. the processors which store a replica of the object) dynamically as the read-write pattern of the object changes in the network. They assume that the changes in the read-write pattern are not known a priori.< >
One of the most important problem, which arised during the creation of distributed software configurations (DSCs) for parallel systems and distributed computer control systems (DCCS), is deadlocks between interacting ...
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One of the most important problem, which arised during the creation of distributed software configurations (DSCs) for parallel systems and distributed computer control systems (DCCS), is deadlocks between interacting processes. Deadlocks are the subject of research, because their influence on normal computersystems behaviour is obvious. In the DCCS oriented software development system ALADDIN/LAMP during DSC debugging and maintenance the problem of deadlocks elimination also was faced. Programming language OCCAM was designed for development of DSCs runing on the transputer networks. This paper deals with the problem of DCCS software components operation reliability increasing by means of deadlock analysis and elimination. As the most important OCCAM language features as the approach to ALADDIN/LAMP tools extention for deadlocks analysis in OCCAM-written DSCs are presented.
Poisson processes with failure intensity functions that are approximately constant are investigated. Maximum likelihood estimation procedures are used to estimate the failure intensity for a fixed level of approximati...
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Model selection based on a predictive performance measure is compared to model selection based on maximum likelihood. Both procedures exhibit unstable relative performance when predictive performance is measured over ...
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Design for dependability has long been an important issue for computersystems. While several dependability analysis tools have been produced, no effort has been made to automate the design for dependability. This pap...
ISBN:
(纸本)9780897913638
Design for dependability has long been an important issue for computersystems. While several dependability analysis tools have been produced, no effort has been made to automate the design for dependability. This paper describes ASSURE, an automated design for dependability advisor, which is part of the MICON system for rapid prototyping of small computersystems. A design for dependability methodology and a formal interface between synthesis and dependability analysis are presented. ASSURE's operation includes dependability analysis, evaluation of dependability enhancement techniques using predictive estimation, and selection of a technique. Different kinds of knowledge used in designing for dependability are identified, including an algorithmic approach for dependability analysis and a knowledge-based approach for suggesting dependability enhancement techniques. Examples of designs produced using ASSURE as a dependability advisor are provided and show an order of magnitude dependability improvement.
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