Medical school essay writing service
How would the chief architect at C use the evolution style? The first step would likely be the definition of the initial and target architectures.
Existing tools make it relatively easy to specify these architectures using standard architecture modeling and visualization techniques. At this point the evolution tools would check that these two architectures satisfy the pre- and postconditions required by the style, perhaps noting situations in which the target architecture is missing certain required structures or is otherwise malformed with respect to the target family. Next, medical school essay writing service the architect starts filling in intermediate stages. The tools would check that the release is well formed and that the path satisfies the constraints of the style, warning the medical school essay writing service architect when it identifies divergences. This process repeats until the architect has fully specified a set of releases and transitions to arrive at the target architecture. To define alternative paths, the architect could follow this same process repeatedly, or instead begin by defining potential intermediate states and then later draw the paths between them. The architect also needs to make decisions about various trade-offs—for example, 4 1. To do this the architect uses one of several parameterized analyses provided by the evolution style. The analyses require the architect to select dimensions of concern and provide weighted utilities. With these annotations in hand, the tools calculate costs and utility, allowing the architect to explore alternative scenarios. Over time, as the evolution proceeds, the architect will update the values and perform recalculations, perhaps leading to revisions of the remaining releases on the path.
The architect also needs to make decisions about various trade-offs.
Again, the architect may want to explore this trade-off between evolution duration on the one hand, and availability or risk on the other. The evaluation functions require the architect to select dimensions of concern and provide weighted utilities. With these annotations in hand, the medical school essay writing service tools calculate costs and utility, allowing the architect to explore alternative scenarios.
Over time, as the evolution proceeds, the architect will update the values and perform recalculations, perhaps leading medical school essay writing service to revisions of the remaining releases on the path. We can help software architects to plan large-scale evolutions of software systems...
Planning a major evolution of a software system presents significant challenges. Moreover, an architect typically has a multitude of choices available—different ways of evolving the system. The task of understanding the trade-offs among the various alternatives and selecting which alternative is optimal with respect to the goals of the particular evolution presents its own significant challenges. This thesis proposes an approach to help the architect navigate this complex maze.
In this dissertation, I argue that many of these difficulties can be ameliorated by providing architects with tools that can leverage collected information about particular domains of evolution and assist the architect in understanding the issues of an evolution, considering alternative ways of evolving the system from its initial architecture to a desired target architecture, and making trade-offs among these alternatives.
While project-planning approaches can be useful for estimating the overall effort involved in carrying out a large-scale software evolution and for making high-level business trade-offs, they are not useful for making detailed architectural decisions about the structure of the evolving system or the order of architectural operations, nor are they useful for analyzing the effect of constraints on the evolving architecture. Thus, to support detailed planning of large-scale evolutions of software systems, this thesis argues that it is necessary to take an architectural approach. The rest of the thesis statement explains the elements of this approach. The first element of the approach that this thesis describes is a theory—a formally defined framework for modeling instances of software architecture evolution. There is not complete agreement on what exactly constitutes a theory, but there is fairly broad consensus that a theory at least includes a set of constructs or entities, propositions that define how the constructs relate, explanations for the propositions, and a characterization of the scope of the theory (the domain to which it is applicable). Gregor distinguishes among five types of theory: analytical (or descriptive) theories, explanatory theories, predictive theories, theories that are both explanatory and predictive, and prescriptive theories. The sort of theory I present in this dissertation is probably best characterized as a prescriptive theory. The provision of the recipe implies that the recipe, if acted upon, will cause an artifact of a certain type to come into being. The appropriateness of including prescription under the label theory has been debated. In particular, it will show how the requirements listed above can be met by viewing an architecture evolution scenario as a directed graph in which intermediate evolution states are represented as nodes, architectural transitions are represented as edges, and evolution paths appear as paths from the node representing the initial state to that representing the target state.
By itself it is just a conceptual model, but it provides a foundation that will support the languages, models, and tools necessary to help software architects plan evolutions. Therefore, we need a language that is sufficiently expressive to capture the constraints that arise naturally in real-world evolution planning. Similarly, the ability to specify analyses or evaluations of candidate evolution paths is necessary for making intelligent trade-offs. This requires a means of expressing analyses in a way that is sufficiently general to reuse analyses across many evolutions and sufficient to express analyses useful for evolution planning. The approach as I have described it so far would be sufficient to model and analyze architecture evolutions in principle, but it would not be useful in practical contexts without adequate tooling. More precisely, they must be reasonably easy to automate in such a way that evaluation of typical constraints and analyses can be completed within reasonable time, even for industrial-scale software systems.