This paper provides a case-study in the field of metric semantics for probabilistic programming. Both an operational and a denotational semantics are presented for an abstract process language pr, which features actio...
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Object technology is an approach that is increasingly being adopted for the development of quality software and software-intensive systems. Recent experience has demonstrated that it provides a sophisticated environme...
ISBN:
(纸本)9780769510507
Object technology is an approach that is increasingly being adopted for the development of quality software and software-intensive systems. Recent experience has demonstrated that it provides a sophisticated environment to support high quality softwareengineering practice. However, the use of object technology should not be restricted to languages but should encompass analysis, design, V&V and many such aspects belonging to the methodological dimension of the development life-cycle. Furthermore, it should also cover other issues belonging to the technological and contextual aspects.
One of the most important methods in communication system design, especially in protocol design, is the composition method. We propose a method for simultaneously composing service specifications and protocol specific...
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One of the most important methods in communication system design, especially in protocol design, is the composition method. We propose a method for simultaneously composing service specifications and protocol specifications based on the LOTOS language. In this method, an asynchronous communication model is adopted which is more realistic in actual communication networks. We use the concept of the weak bisimulation equivalence to represent the correctness of composition. A software support system based on the proposed composition method is also described.
This paper provides a case-study in the field of metric semantics for probabilistic programming. Both an operational and a denotational semantics are presented for an abstract process language Download : Download full...
This paper provides a case-study in the field of metric semantics for probabilistic programming. Both an operational and a denotational semantics are presented for an abstract process language
Download : Download full-size image pr , which features action refinement and probabilistic choice. The two models are constructed in the setting of complete ultrametric spaces, here based on probability measures of compact support over sequences of actions. It is shown that the standard toolkit for metric semantics works well in the probabilistic context of
Download : Download full-size image pr , e.g. in establishing the correctness of the denotational semantics with respect to the operational one. In addition, it is shown how the method of proving full abstraction —as proposed recently by the authors for a nondeterministic language with action refinement—can be adapted to deal with the probabilistic language
Download : Download full-size image pr as well.
Before designing safety- or mission-critical real-time systems, a specification of the required behaviour of the system should be produced and reviewed by domain experts. After the system has been implemented, it shou...
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ISBN:
(纸本)1581132662
Before designing safety- or mission-critical real-time systems, a specification of the required behaviour of the system should be produced and reviewed by domain experts. After the system has been implemented, it should be thoroughly tested to ensure that it behaves correctly. This is best done using a monitor, a system that observes the behaviour of a target system and reports if that behaviour is consistent with the requirements. Such a monitor can be used both as an oracle during testing and as a supervisor during operation. Monitors should be based on the documented requirements of the system. If the target system is required to monitor or control real-valued quantities, then the requirements, which are expressed in terms of the monitored and controlled quantities, will allow a range of behaviours to account for errors and imprecision in observation and control of these quantities. Even if the controlled variables are discrete valued, the requirements must specify the timing tolerance. Because of the limitations of the devices used by the monitor to observe the environmental quantities, there is unavoidable potential for false reports, both negative and positive. This paper discusses design of monitors for real-time systems, and examines the conditions under which a monitor will produce false reports. We describe the conclusions that can be drawn when using a monitor to observe system behaviour.
We present a method of test generation for acyclic sequential circuits with hold registers. A complete (100% fault efficiency) test sequence for an acyclic sequential circuit can be obtained by applying a combinationa...
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We present a method of test generation for acyclic sequential circuits with hold registers. A complete (100% fault efficiency) test sequence for an acyclic sequential circuit can be obtained by applying a combinational test generator to all the maximal time-expansion models (TEMs) of the circuit. We propose a class of acyclic sequential circuits for which the number of maximal TEMs is one, i.e, the maximum TEM exists. For a circuit in the class, test generation can be performed by using only the maximum TEM. The proposed class of sequential circuits with the maximum TEM properly includes several known classes of acyclic sequential circuits such as balanced structures and acyclic sequential circuits without hold registers for which test generation can be also performed by using a combinational test generator. Therefore, in general, the hardware overhead for partial scan based on the proposed structure is smaller than that based on balanced or acyclic sequential structure without hold registers.
With the expansion of the areas of database applications, the amount of data processed has become gigantic, and the demand for faster database systems has increasingly intensified. Thus, many efforts have been expende...
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With the expansion of the areas of database applications, the amount of data processed has become gigantic, and the demand for faster database systems has increasingly intensified. Thus, many efforts have been expended to execute database operations more efficiently using special hardware. However, for the cases in which mass-produced LSI cannot be used, cost has become excessive, and replacement methods have been sought. Vector processors have powerful pipeline operators and large-capacity main memories and have rapidly spread in recent years. In this paper, algorithms for relational database operations suitable for vector processors showing the characteristics of vector processors sufficiently are presented. This algorithm is based on the hash method, which is highly efficient when the capacity of the main memory is large, and it is shown that a rate of acceleration more than 10 times the average is obtained for representative relational database operations when this algorithm is executed on a vector processor.
Micro kernel architecture is widely used in the design of operating systems. However, traditional micro kernels are not easily extensible and so are not very flexible. For example, the granularity of kernel functions ...
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Micro kernel architecture is widely used in the design of operating systems. However, traditional micro kernels are not easily extensible and so are not very flexible. For example, the granularity of kernel functions does not accord with the users' needs. Moreover, users cannot customize kernel functions easily. Another problem of micro kernels is that system performance is poor due to the overhead of switching address spaces and due to the increased interprocess communication in micro kernels. To address these problems, we have designed and implemented the Lavender micro kernel. Lavender is a micro kernel which can be customized according to application-specific requirements. In order to reduce kernel overhead due to switching address spaces and interprocess communication, Lavender provides users with functionality for process groups and for resident address space. By means of this functionality, the overhead of interprocess procedure calls is reduced to about one-fifth that of other micro kernels. In this paper, the structure and features of Lavender are described. Furthermore, a performance evaluation of process groups and resident address space is presented and the effectiveness of Lavender is discussed.
We present a method of test generation for acyclic sequential circuits with hold registers. A complete (100% fault efficiency) test sequence for an acyclic sequential circuit can be obtained by applying a combinationa...
详细信息
We present a method of test generation for acyclic sequential circuits with hold registers. A complete (100% fault efficiency) test sequence for an acyclic sequential circuit can be obtained by applying a combinational test generator to all the maximal time-expansion models (TEMs) of the circuit. We propose a class of acyclic sequential circuits for which the number of maximal TEMs is one, i.e., the maximum TEM exists. For a circuit in the class, test generation can be performed by using only the maximum TEM. The proposed class of sequential circuits with the maximum TEM properly includes several known classes of acyclic sequential circuits such as balanced structures and acyclic sequential circuits without hold registers for which test generation can also be performed by using a combinational test generator. Therefore, in general, the hardware overhead for partial scan based on the proposed structure is smaller than that based on balanced or acyclic sequential structure without hold registers.
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