The use of sequencing information in software specification for verification

Software requirements specifications, virtual machine definitions, and algorithmic design all place constraints on the sequence of operations that are permissible during a program's execution. This paper discusses how these constraints can be captured and used to aid in the program verification process. The sequencing constraints can be expressed as a grammar over the alphabet of program operations. Several techniques can be used in support of testing or verification based on these specifications. Dynamic aalysis and static analysis are considered here. The automatic generation of some of these aids is feasible; the means of doing so is described

Spasticity: a problem of disordered motor function

Thesis (M.D.)--Boston Universit

Arcadia, a software development environment research project

The research objectives of the Arcadia project are two-fold: discovery and development of environment architecture principles and creation of novel software development tools, particularly powerful analysis tools, which will function within an environment built upon these architectural principles.Work in the architecture area is concerned with providing the framework to support integration while also supporting the often conflicting goal of extensibility. Thus, this area of research is directed toward achieving external integration by providing a consistent, uniform user interface, while still admitting customization and addition of new tools and interface functions. In an effort to also attain internal integration, research is aimed at developing mechanisms for structuring and managing the tools and data objects that populate a software development environment, while facilitating the insertion of new kinds of tools and new classes of objects.The unifying theme of work in the tools area is support for effective analysis at every stage of a software development project. Research is directed toward tools suitable for analyzing pre-implementation descriptions of software, software itself, and towards the production of testing and debugging tools. In many cases, these tools are specifically tailored for applicability to concurrent, distributed, or real-time software systems.The initial focus of Arcadia research is on creating a prototype environment, embodying the architectural principles, which supports Ada1 software development. This prototype environment is itself being developed in Ada.Arcadia is being developed by a consortium of researchers from the University of California at Irvine, the University of Colorado at Boulder, the University of Massachusetts at Amherst, TRW, Incremental Systems Corporation, and The Aerospace Corporation. This paper delineates the research objectives and describes the approaches being taken, the organization of the research endeavor, and current status of the work

A Toxic Substance Obtained by Growing Hemolytic Streptococci in a Special Medium*

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A metaphor and a conceptual architecture for software development environments

A conceptual architecture for software development environments (SDEs) is presented in terms of a new metaphor drawn from business enterprises. A metaphor is employed as the architecture is complex, requiring understanding from several perspectives. The metaphor provides a rich set of familiar concepts that strongly aid in understanding the environment architecture and software production. The metaphor is applicable to individual programming environments, software development environments supporting teams of developers, and to large-scale software production as a whole.The paper begins by considering three perspectives on SDEs, a function-based view, an objects-and-relations view, and a process-centered view. The process view, being the most encompassing, is held through the remainder of the paper. Three metaphors for organizing and explaining a process-centered environment are then examined, including the hierarchical contract model and the individual/family/city/state model. Next the corporation model is introduced and a detailed analogy is drawn between corporations and software development environments. Within the context of the corporation metaphor, three corporate organization schemes are reviewed and federal decentralization is argued to be most appropriate for an SDE. Relationships induced by such an organization are discussed and a mapping between the conceptual architecture and a possible implementation architecture is briefly discussed

Why didn't economists predict the Great Depression?

Economists failed to forecast the Great Depression, perhaps because they had lacked reason to theorize enough about business cycles. Since theory is a public good, the market produces too little of it. The prospect of ex post fame may induce theory; but fame comes from explaining famous events, not from averting adverse events. Also, learning-by-doing induces theory by cutting its cost, favoring the first theories to be developed. These dealt with markets – not business cycles – in the decades before the Depression

The theory of money supply: a case study

The theory of money supply is less developed than that of money demand, largely because 19th-century economists believed that money was unimportant and because they viewed the central bank as either an appendage to the economy or as a welfare-maximizing black box. The paper reviews each of these beliefs in turn

When will privatization maximize the government's net revenues?

Governments often sell assets for revenues or economic efficiency. When the capital is durable, potential buyers may wait for the government to cut its price, since they know that as a monopoly it will initially price above marginal cost. Rather than sell, the government could continue to lease the capital to the public – that is, to sell the services that the capital generates, in exchange for a tax payment. Comparative statics indicate that a government maximizing its net revenues may prefer leasing to selling for a large inventory of capital-intensive products that buyers view as vital. For example, a socialist government contemplating a transition to markets must consider the impact on its own revenues. If its major assets are capital-intensive, the impact may be negative

When will privatization maximize the government's net revenues?

Governments often sell assets for revenues or economic efficiency. When the capital is durable, potential buyers may wait for the government to cut its price, since they know that as a monopoly it will initially price above marginal cost. Rather than sell, the government could continue to lease the capital to the public – that is, to sell the services that the capital generates, in exchange for a tax payment. Comparative statics indicate that a government maximizing its net revenues may prefer leasing to selling for a large inventory of capital-intensive products that buyers view as vital. For example, a socialist government contemplating a transition to markets must consider the impact on its own revenues. If its major assets are capital-intensive, the impact may be negative