Reconciling Synthesis and Decomposition: A Composite Approach to Capability Identification

Stakeholders' expectations and technology constantly evolve during the lengthy development cycles of a large-scale computer based system. Consequently, the traditional approach of baselining requirements results in an unsatisfactory system because it is ill-equipped to accommodate such change. In contrast, systems constructed on the basis of Capabilities are more change-tolerant; Capabilities are functional abstractions that are neither as amorphous as user needs nor as rigid as system requirements. Alternatively, Capabilities are aggregates that capture desired functionality from the users' needs, and are designed to exhibit desirable software engineering characteristics of high cohesion, low coupling and optimum abstraction levels. To formulate these functional abstractions we develop and investigate two algorithms for Capability identification: Synthesis and Decomposition. The synthesis algorithm aggregates detailed rudimentary elements of the system to form Capabilities. In contrast, the decomposition algorithm determines Capabilities by recursively partitioning the overall mission of the system into more detailed entities. Empirical analysis on a small computer based library system reveals that neither approach is sufficient by itself. However, a composite algorithm based on a complementary approach reconciling the two polar perspectives results in a more feasible set of Capabilities. In particular, the composite algorithm formulates Capabilities using the cohesion and coupling measures as defined by the decomposition algorithm and the abstraction level as determined by the synthesis algorithm.Comment: This paper appears in the 14th Annual IEEE International Conference and Workshop on the Engineering of Computer Based Systems (ECBS); 10 pages, 9 figure

Characteristics of Waterfowl Harvest at Horseshoe Lake, Madison County, Illinois

Division of Wildlife Resources Migratory Bird Section, Periodic Report No. 13Report issued on: April 21, 197

Achieving Asynchronous Speedup While Preserving Synchronous Semantics: An Implementation of Instructional Footprinting in Linda

Linda is a coordination language designed to support process creation and inter-process communication within conventional computational languages. Although the Linda paradigm touts architectural and language independence, it often suffers performance penalties, particularly on local area network platforms. Instructional Footprinting is an optimization technique with the primary goal of enhancing the execution speed of Linda programs. The two main aspects of Instructional Footprinting are instructional decomposition and code motion. This paper addresses the semantic issues encountered when the Linda primitives, IN and RD, are decomposed and moved past other Linda operations. Formal semantics are given as well as results showing significant speedup (as high as 64%) when Instructional Footprinting is used

An Objectives-Driven Process for Selecting Methods to Support Requirements Engineering Activities

This paper presents a framework that guides the requirements engineer in the implementation and execution of an effective requirements generation process. We achieve this goal by providing a well-defined requirements engineering model and a criteria based process for optimizing method selection for attendant activities. Our model, unlike other models, addresses the complete requirements generation process and consists of activities defined at more adequate levels of abstraction. Additionally, activity objectives are identified and explicitly stated - not implied as in the current models. Activity objectives are crucial as they drive the selection of methods for each activity. Our model also incorporates a unique approach to verification and validation that enhances quality and reduces the cost of generating requirements. To assist in the selection of methods, we have mapped commonly used methods to activities based on their objectives. In addition, we have identified method selection criteria and prescribed a reduced set of methods that optimize these criteria for each activity defined by our requirements generation process. Thus, the defined approach assists in the task of selecting methods by using selection criteria to reduce a large collection of potential methods to a smaller, manageable set. The model and the set of methods, taken together, provide the much needed guidance for the effective implementation and execution of the requirements generation process.Comment: 20 pages, 5 figures, 3 tables, publisheed: 29th Annual IEEE/NASA Software Engineering Workshop, April 200