In safety-critical systems, the potential impact of each separate failure is normally studied in detail and remedied by adding backups. Failure combinations, though, are rarely studied exhaustively; there are just too...
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In safety-critical systems, the potential impact of each separate failure is normally studied in detail and remedied by adding backups. Failure combinations, though, are rarely studied exhaustively; there are just too many of them, and most have a low probability of occurrence. Defect detection in software development is usually understood to be a best effort at rigorous testing just before deployment. But defects can be introduced in all phases of software design, not just in the final coding phase. Defect detection therefore shouldn't be limited to the end of the process, but practiced from the very beginning. In a rigorous model-based engineering process, each phase is based on the construction of verifiable models that capture the main decisions.
The development of small-scale quantum devices raises the question of how to fairly assess and detect quantum speedup. Here, we show how to define and measure quantum speedup and how to avoid pitfalls that might mask ...
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The development of small-scale quantum devices raises the question of how to fairly assess and detect quantum speedup. Here, we show how to define and measure quantum speedup and how to avoid pitfalls that might mask or fake such a speedup. We illustrate our discussion with data from tests run on a D-Wave Two device with up to 503 qubits. By using random spin glass instances as a benchmark, we found no evidence of quantum speedup when the entire data set is considered and obtained inconclusive results when comparing subsets of instances on an instance-by-instance basis. Our results do not rule out the possibility of speedup for other classes of problems and illustrate the subtle nature of the quantum speedup question.
In this second and final part of this series, the authors offer help in choosing which of the three spreadsheets - Visi-Calc, Multiplan and Lotus 1-2-3 - is the best for his or her particular use. The choice of which ...
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In this second and final part of this series, the authors offer help in choosing which of the three spreadsheets - Visi-Calc, Multiplan and Lotus 1-2-3 - is the best for his or her particular use. The choice of which package comes down to the needs and capabilities of the individual user. Many first time users and occasional users find that one of the less complicated packages with fewer features and fewer choices makes it easier for them to use the spreadsheet concept. The industrial engineer should know how to use a spreadsheet correctly and efficiently so that he may be aware of the many potential uses of this valuable tool. Refs.
In a stationary Ornstein-Uhlenbeck process, the Guassian variabley(0, 1) has serial correlation given bywhere ρδtis the correlation between observations separated by time interval δt, and the constantais such thate...
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In a stationary Ornstein-Uhlenbeck process, the Guassian variabley(0, 1) has serial correlation given bywhere ρδtis the correlation between observations separated by time interval δt, and the constantais such thate-ais the correlation between observations separated by one unit of time. In any finite length of time, saymhours, there will be a minimum and a maximum ofywhose probability distributions are of great operational importance, but which have never been determined with exactness. The author has approximated the distribution of miny(t) in time interval 0
The need exists for specifying software reliability requirements and for performing reliability assessments of developed software to insure that these requirements are being met. To help satisfy these needs, a long-te...
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The need exists for specifying software reliability requirements and for performing reliability assessments of developed software to insure that these requirements are being met. To help satisfy these needs, a long-term effort has been initiated to develop a handbook for software reliability assessment, similar to MIL-HDBK-217, that can be used by appropriate Air Force personnel in specifying and assessing software reliability requirements. This paper outlines the status of this effort, with emphasis on the initial version of this proposed handbook that will serve as an interim guide to software reliability assessment, and on the nonhomogeneous Poisson process software reliability prediction model that forms the basis of this initial guidebook.
A new procedure for numerical optimization of constrained nonlinear problems is described. The method makes use of an efficient “Boundary Tracking” strategy to move on the constraint surfaces. In a comparison study ...
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A new procedure for numerical optimization of constrained nonlinear problems is described. The method makes use of an efficient “Boundary Tracking” strategy to move on the constraint surfaces. In a comparison study it was found to be an effective method for treating nonlinear mathematical programming problems particularly those with difficult nonlinear constraints.
A root of a function is the locus for the independent variable(s) when the function is equal to zero. Numerical analysis offers a good number of algorithms to determine the root(s) of a function. This article includes...
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A root of a function is the locus for the independent variable(s) when the function is equal to zero. Numerical analysis offers a good number of algorithms to determine the root(s) of a function. This article includes a general view of the subject and methods classifications, criteria for convergence, speed comparisons in obtaining the root, a review of eleven basic methods for single real functions, and a discussion of the two schemes used, as well as a presentation of Pascal functions and procedures for some of the above.
Biomedical ontologies are often very large and complex. Only a subset of the ontology may be needed for a specified application or community. For ontology end users, it is desirable to have community-based labels rath...
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Biomedical ontologies are often very large and complex. Only a subset of the ontology may be needed for a specified application or community. For ontology end users, it is desirable to have community-based labels rather than the labels generated by ontology developers. Ontodog is a web-based system that can generate an ontology subset based on Excel input, and support generation of an ontology community view, which is defined as the whole or a subset of the source ontology with user-specified annotations including user-preferred labels. Ontodog allows users to easily generate community views with minimal ontology knowledge and no programming skills or installation required. Currently 4100 ontologies including all OBO Foundry ontologies are available to generate the views based on user needs. We demonstrate the application of Ontodog for the generation of community views using the Ontology for Biomedical Investigations as the source ontology.
The programming of some Pascal loops which have two possible reasons for exit are examined. In particular the use of state variables is considered. Within the loop, a variable of an enumerated type records the current...
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The programming of some Pascal loops which have two possible reasons for exit are examined. In particular the use of state variables is considered. Within the loop, a variable of an enumerated type records the current state of interest, and upon exit from the loop, a case-statement discriminates the possible resultant states. This approach applies to loops with an arbitrary number of reasons for exit. Use of this technique can make programs easier to write and they become more transparent and reliable. The approach is recommended for all but the most straightforward loops with more than one reason for exit.
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