Investigating Advances in the Acquisition of Secure Systems Based on Open Architecture, Open Source Software, and Software Product Lines

Naval Postgraduate School Acquisition Research Progra

Software Licenses in Context: The Challenge of Heterogeneously-Licensed Systems

The prevailing approach to free/open source software and licenses has been that each system is developed, distributed, and used under the terms of a single license. But it is increasingly common for information systems and other software to be composed with components from a variety of sources, and with a diversity of licenses. This may result in possible license conflicts and organizational liability for failure to fulfill license obligations. Research and practice to date have not kept up with this sea-change in software licensing arising from free/open source software development. System consumers and users consequently rely on ad hoc heuristics (or costly legal advice) to determine which license rights and obligations are in effect, often with less than optimal results; consulting services are offered to identify unknowing unauthorized use of licensed software in information systems; and researchers have shown how the choice of a (single) specific license for a product affects project success and system adoption. Legal scholars have examined how pairs of software licenses conflict but only in simple contexts. We present an approach for understanding and modeling software licenses, as well as for analyzing conflicts among groups of licenses in realistic system contexts, and for guiding the acquisition, integration, or development of systems with free/open source components in such an environment. This work is based on an empirical analysis of representative software licenses and of heterogeneously-licensed systems. Our approach provides guidance for achieving a “best-of-breed” component strategy while obtaining desired license rights in exchange for acceptable obligations

Relationships between scenarios

Abstract. Scenarios are widely used in requirements analysis and other activities, but their informality is a challenge for reasoning about them and providing significant tool support. This research describes an approach for identifying aspects of scenarios that people use consistently, structuring them, and using this structure to support work with scenarios. Our approach clarifies how scenarios can be related (for example by specialization) and how they can be used to give each other context and constraints, and provides a foundation for more extensive automated support. Automated support for scenario manipulation and analysis lets human expertise be concentrated on the tasks that need it most. Our approach is implemented by an XML language and a Java package for it. We describe how they have been used in goal-driven specificationbased testing, computed social worlds of autonomous animated agents, and analysis of business rules and scenarios

Temporally expressive scenarios in ScenarioML

Sequential, non-overlapping events are the norm in traditionally-expressed scenarios and use cases, but the world is much more fluid. Events have duration and may overlap, be separated in time, begin or end together, or have various other specific temporal relations. The ordering of the events may be completely known or partially uncertain, resulting in any of a large (but finite) number of relations for any two events. These relations, which can be formally stated and manipulated, are separable in form and meaning from the events themselves, which in requirements are most often expressed in prose. The temporal relations and partial ordering of events can be a significant part of what is specified, and must be inferred by a reader if not explicitly expressed. This paper presents a scenario language, ScenarioML, which expresses requirements scenarios using a broad and effective selection of event relations and structures. ScenarioML scenarios range from concrete scenarios to parameterized schemata that represent large families of scenarios related in a variety of temporal and structural ways. The language is designed for automated analysis and operations on temporal event relations, as well as other aspects of scenarios. An example from aircraft navigation is presented

business rules, and matching

Scenarios (or use cases) and business rules each have strengths and offer mutually reinforcing views of a software system. Scenarios describe uses of a system in terms of situations, interactions, and events unfolding over time. Business rules describe fundamental constraints on a system’s transactions. However, analysis of scenarios and business rules together can be challenging. We present an approach for evaluating these two distinct views in combination. We operationalize business rules as scenarios that must match the world in every appropriate context, or as negative scenarios that must not match. Scenarios are patterns that can match occurrences in the world; a system whose behavior meets its requirements results in occurrences that its scenarios match successfully. We mediate the interaction of business rules and scenarios through comatching events appearing in two or more scenarios. A co-matched event is not judged to have successfully matched unless all the events that co-match it do. A case study of business rules for automated teller machines illustrates our approach

Software Support for Calculations in Allen's Interval Algebra

This report gives a compact introduction to interval algebra and describes a software tool, allen, for working with interval algebra relations. In connection with this tool, we propose a convenient notation for Allen's basic relations in which each relation is represented by a single lower or uppercase lette

Achieving Better Buying Power for Mobile Open Architecture Software Systems Through Diverse Acquisition Scenarios

Naval Postgraduate School Acquisition Research Progra

Achieving Better Buying Power through Acquisition of Open Architecture Software Systems for Web and Mobile Devices

Naval Postgraduate School Acquisition Research Progra