Understanding the behavior of a system is crucial in being able to modify, maintain, and improve the system. A particularly difficult aspect of some system behaviors is concurrency. While there are many techniques to ...
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Understanding the behavior of a system is crucial in being able to modify, maintain, and improve the system. A particularly difficult aspect of some system behaviors is concurrency. While there are many techniques to specify intended concurrent behavior, there are few, if any, techniques to capture and model actual concurrent behavior. This paper presents a technique to discover patterns of concurrent behavior from traces of system events. The technique is based on a probabilistic analysis of the event traces. Using metrics for the number, frequency, and regularity of event occurrences, a determination is made of the likely concurrent behavior being manifested by the system. The technique is useful in a wide variety of software engineering tasks, including architecture discovery, reengineering, user interaction modeling, and software process improvement.
Recent years have seen increasing interest in systems that reason about and manipulate executable code. Such systems can generally benefit from information about aliasing. Unfortunately, most existing alias analyses a...
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ISBN:
(纸本)9780897919791
Recent years have seen increasing interest in systems that reason about and manipulate executable code. Such systems can generally benefit from information about aliasing. Unfortunately, most existing alias analyses are formulated in terms of high-level language features, and are unable to cope with features, such as pointer arithmetic, that pervade executable programs. This paper describes a simple algorithm that can be used to obtain aliasing information for executable code. In order to be practical, the algorithm is careful to keep its memory requirements low, sacrificing precision where necessary to achieve this goal. Experimental results indicate that it is nevertheless able to provide a reasonable amount of information about memory references across a variety of benchmark programs.
Two techniques for improving garbage collection were presented, namely, generational stack collection and profile-driven pretenuring. The first is applicable to stack based implementations of functional languages whil...
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Two techniques for improving garbage collection were presented, namely, generational stack collection and profile-driven pretenuring. The first is applicable to stack based implementations of functional languages while the second is useful for any generational collector. Both techniques were implemented in a generational collector used by the TIL compiler and have observed decreases in garbage collection times of as much as 70% and 30%, respectively.
We describe a foundational language for specifying dynamically evolving networks of distributed processes, Dπ. The language is a distributed extension of the π-calculus which incorporates the notions of remote execu...
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We describe a foundational language for specifying dynamically evolving networks of distributed processes, Dπ. The language is a distributed extension of the π-calculus which incorporates the notions of remote execution, migration, and site failure. Novel features of Dπ include: 1. Communication channels are explicitly located: the use of a channel requires knowledge of both the channel and its location. 2. Names are endowed with permissions: the holder of a name may only use that name in the manner allowed by these permissions. A type system is proposed in which the types control the allocation of permissions;in well-typed processes all names are used in accordance with the permissions allowed by the types. We prove Subject Reduction and Type Safety Theorems for the type system. In the final section we define a semantic theory based on barbed bisimulations and discuss its characterization in terms of a bisimulation relation over a relativized labelled transition system.
The purpose of safety case is to argue that a system is acceptably safe to operate in a specified context. Common argument approaches exist between safety case developments. Informal reuse of safety case material alre...
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The purpose of safety case is to argue that a system is acceptably safe to operate in a specified context. Common argument approaches exist between safety case developments. Informal reuse of safety case material already occurs, but in an uncontrolled, unpredictable and potentially dangerous manner. Based on the principles of design patterns combined with the safety argument representation concepts provided by the goal structuring notation, the concept of safety case patterns is developed. Using these patterns, it is possible to identify and record reusable arguments in a number of situations and at different levels within the safety case.
The proceedings contains 3 papers from the 1998 IEE Colloquium on Understanding Patterns and Their Application to systems Engineering. Topics discussed include: architecture-driven and pattern-based techniques for obj...
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The proceedings contains 3 papers from the 1998 IEE Colloquium on Understanding Patterns and Their Application to systems Engineering. Topics discussed include: architecture-driven and pattern-based techniques for object re-engineering (ADAPTOR);CREWS validation frames;and safety case patterns.
The growing class of portable systems, such as personal computing and communication devices, has resulted in a new set of system design requirements, mainly characterized by dominant importance of power minimization a...
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The growing class of portable systems, such as personal computing and communication devices, has resulted in a new set of system design requirements, mainly characterized by dominant importance of power minimization and design reuse. We develop the design methodology for the low power core-based real-time system-on-chip based on dynamically variable voltage hardware. The key challenge is to develop effective scheduling techniques that treat voltage as a variable to be determined, in addition to the conventional task scheduling and allocation. Our synthesis technique also addresses the selection of the processor core and the determination of the instruction and data cache size and configuration so as to fully exploit dynamically variable voltage hardware, which result in significantly lower power consumption for a set of target applications than existing techniques. The highlight of the proposed approach is the non-preemptive scheduling heuristic which results in solutions very close to optimal ones for many test cases. The effectiveness of the approach is demonstrated on a variety of modern industrial-strength multimedia and communication applications.
A set of PC tools has been developed by the authors to make computer simulation accessible for clinical laboratories planning to restructure or to automate their operations. The new tools include modules for the gener...
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A set of PC tools has been developed by the authors to make computer simulation accessible for clinical laboratories planning to restructure or to automate their operations. The new tools include modules for the generation of specific workflow files (requests and arrival rates) and for the immediate visualization and assessment of experimental results. These two tools cooperate with a simulation package called Simlab(R), which the authors developed earlier. Simlab describes the design of any kind of laboratory in terms of work ureas, staffing, instrumentation, tubes, tests, and routings and produces useful performance data for a. given experimental scenario. These performance data include hourly utilization patterns for each individual staff member and piece of equipment, hourly sample queue patterns in front of each workplace, and turnaround times for stat and routine orders. Simlab in combination with the new tools is used for the authors' technology-based services in laboratory workflow analysis. An example can be downloaded from the authors' Web site at http://***. (C) 1998 John Wiley & Sons, Inc.
In-System programming (ISP) is evolving from a good concept to essential practice in the latest miniaturized and fast-to-market designs. This paper studies the fast growing technique of In-System programming Flash mem...
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In-System programming (ISP) is evolving from a good concept to essential practice in the latest miniaturized and fast-to-market designs. This paper studies the fast growing technique of In-System programming Flash memories using JTAG access methods which is being employed as an emulation port.
The familiar Hindley-Milner type system of the ML language family is extended with monad annotations to account for possible side effects of expression evaluation. This also allows effects to be effectively encapsulat...
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The familiar Hindley-Milner type system of the ML language family is extended with monad annotations to account for possible side effects of expression evaluation. This also allows effects to be effectively encapsulated by lexical scopesΓ with enforcement provided by type checking. A type-and-effects analysis supports type inference. Type soundness and completeness theorems establish the coherence of monadic type inference with the reference semantics of a small ML-style language.
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