Informal and graphical modeling techniques enable developers to construct abstract representations of systems. Object-oriented modeling techniques further facilitate the development process. The Unified modeling Langu...
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ISBN:
(纸本)9780769510507
Informal and graphical modeling techniques enable developers to construct abstract representations of systems. Object-oriented modeling techniques further facilitate the development process. The Unified modeling Language (UML), an object-oriented modeling approach, could be broad enough in scope to represent a variety of domains and gain widespread use. Currently, UML comprises several different notations with no formal semantics attached to the individual diagrams. Therefore, it is not possible to apply rigorous automated analysis or to execute a UML model in order to test its behavior, short of writing code and performing exhaustive testing. We introduce a general framework for formalizing a subset of UML diagrams in terms of different formal languages based on a homomorphic mapping between metamodels describing UML and the formal language. This framework enables the construction of a consistent set of rules for transforming UML models into specifications in the formal language. The resulting specifications derived from UML diagrams enable either execution through simulation or analysis through model checking, using existing tools. This paper describes the use of this framework for formalizing UML to model and analyze embeddedsystems. A prototype system for generating the formal specifications and results from an industrial case study are also described.
This paper describes an object-oriented model and a reuse-oriented methodology for the co-design of embeddedcomputersystems. Our approach is based on a hierarchy of classes which describes all possible specification...
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This paper describes an object-oriented model and a reuse-oriented methodology for the co-design of embeddedcomputersystems. Our approach is based on a hierarchy of classes which describes all possible specifications of systems of a certain domain, the behavior of hard- and software-components, and the target-architectures. The content of this knowledge base (re-usable, formalized descriptions) is determined by the analysis of known systems. We present solutions for a specification methodology, the modeling of heterogeneous systems by task graphs, and the mapping process from specified requirements down to hard- or software components in a target architecture. This approach is illustrated by functions of the domain of robot controls.
Different distributed environmental simulationsystems are presented They take advantage of the possibilities of modern network technologies to gather input data, perform simulation and spread the simulation results. ...
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ISBN:
(纸本)0769508103
Different distributed environmental simulationsystems are presented They take advantage of the possibilities of modern network technologies to gather input data, perform simulation and spread the simulation results. The term 'distributed' applies in this context both to the simulation, this is a parallel (distributed) simulation on computer networks, and to the fact, that all components (pre- and postprocessing and the simulation models) may reside in different locations and will be accessed via the Web. The systems described use this architecture to a different extent. Based on this it is shown, that it should be possible to build a system which links various data sources, simulation models, visualization and information tools, all of them running possibly remotely on the corresponding hardware. Such a system would form a distributed virtual laboratory.
This paper describes an object-oriented model and a reuse-oriented methodology for the co-design of embeddedcomputersystems. Our approach is based on a hierarchy of classes which describes all possible specification...
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VHPI is the VHDL Procedural Interface, an IEEE standards effort, with an ANSI C interface for developing models and applications that are easily integrated into a compliant simulation tool. VHPI provides sufficient ac...
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VHPI is the VHDL Procedural Interface, an IEEE standards effort, with an ANSI C interface for developing models and applications that are easily integrated into a compliant simulation tool. VHPI provides sufficient access to the runtime data model to implement foreign architectures equivalent to those which can be described in VHDL. This paper examines how the control and data flow features of VHPI can be used for modeling foreign architectures.
High level modeling and (quantitative) performance analysis of signal processing systems requires high level models for the applications (algorithms) and the implementations (architecture), a mapping of the former int...
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High level modeling and (quantitative) performance analysis of signal processing systems requires high level models for the applications (algorithms) and the implementations (architecture), a mapping of the former into the latter, and a simulator for fast execution of the whole. Signal processing algorithms are very often nested-loop algorithms with a high degree of inherent parallelism. This paper presents - for such applications - suitable application and implementation models, a method to convert a given imperative executable specification to a specification in terms of the application model, a method to map this specification into an architecture specification in terms of the implementation model, and a method to analyze the performance through simulation. The methods and tools are illustrated by means of an example.
An object-oriented modeling infrastructure using the Java-based, Silk simulation classes is defined that enables the simulation of multitasking, distributed systems using symmetric multiprocessors. The simulation infr...
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An object-oriented modeling infrastructure using the Java-based, Silk simulation classes is defined that enables the simulation of multitasking, distributed systems using symmetric multiprocessors. The simulation infrastructure is being used to evaluate alternative architectures for embedded, distributed systems. We show how the underlying structure is adapted to several different applications, including various Internet applications. The paper describes the infrastructure, its robustness, and the application of the model to produce insights for a system under design. The simulation infrastructure enables a high fidelity representation of the internal complexity of the application on each processing node, the operating system behavior, and the disks and network. The simple yet powerful representation leverages the use of the Silk entity-thread architecture to achieve a simulation architecture that maps to the actual system architecture in both conceptual design and processing sequence. The model has been validated through instrumentation of the evolving target system.
This paper explores the problem of efficiently ordering interprocessor communication operations in statically-scheduled multiprocessors for iterative dataflow graphs. In most digital signal processing applications, th...
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This paper explores the problem of efficiently ordering interprocessor communication operations in statically-scheduled multiprocessors for iterative dataflow graphs. In most digital signal processing applications, the throughput of the system is significantly affected by communication costs. By explicitly modeling these costs within an effective graph-theoretic analysis framework, we show that ordered transaction schedules can significantly outperform self-timed schedules even when synchronization costs are low. However, we also show that when communication latencies are non-negligible, finding an optimal transaction order given a static schedule is an NP-complete problem and that this intractability holds both under iterative and non-iterative execution. We develop new heuristics for finding efficient transaction orders, and perform an experimental comparison to gauge the performance of these heuristics.
Scheduling simulators are useful in the design exploration phase of the development of reactive embedded real-time computersystems. However, most conventional scheduling simulators do not fulfil all the requirements ...
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Scheduling simulators are useful in the design exploration phase of the development of reactive embedded real-time computersystems. However, most conventional scheduling simulators do not fulfil all the requirements needed for the modeling of application functionality and system environment. Other system modeling approaches exist for this purpose, but these usually do not deal with scheduling aspects. This paper proposes an new approach to the modeling and simulation of both functional and scheduling aspects of real-time systems. The new approach is based on Petri nets and uses a principle called delegated execution. The main idea is to associate time progress with an explicit scheduler subnet instead of the task structure. Advantages of this approach are the ability to model preemptive scheduling, to combine an application with several schedulers, and to reuse standard scheduler models. The modeling methodology is demonstrated using the well-known mine drainage system case study.
We propose an efficient strategy for resource management for scalable QoS guaranteed real-time communication services. This strategy is based on sink trees, and is particularly well suited for differentiated-services ...
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ISBN:
(纸本)0769509304
We propose an efficient strategy for resource management for scalable QoS guaranteed real-time communication services. This strategy is based on sink trees, and is particularly well suited for differentiated-services based architectures. We first show that finding a set of sink-trees in a given network is NP-complete. Then we propose a heuristic algorithm that always efficiently produces a set of sink-trees for a given network. Sink-tree based resource management integrates routing and resource reservation along the routes, and therefore has a number of advantages over other resource management scheme, in terms of: admission probability, link resource utilization, flow set up latency, signaling over-head, and routing over-head. In this paper we show by simulation experiments that even for simple cases the sink-tree based approach shows excellent results in terms of admission probability.
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