Architecture description can be modeled as a set of alternative choices and decisions, where the rationale and tradeoffs for each decision are documented and understood as needed to inform subsequent decisions. Each decision, based on ISO/IEC/IEEE 42010, pertains to one or more stakeholder concerns. These concerns combined with the system environment and scenarios provide architecture design context that clarifies the motivation for decisions. Subsequent authors have introduced the notion of an influencing decision force, using a many-to-many relationship with concern, to provide further context for decisions. For both concerns and forces it is left to the architect to identify the nature of this context. This paper proposes a systematic process for identifying and documenting design context in support of architectural decisions. For our work decision force is used as a central unifying aspect of the architecture framework metamodel. We extend the decision Forces Viewpoint to capture detailed design context descriptions, and add features for tagging the architecture description elements to facilitate identification of commonality, classification, and specialization. Initial feedback from industry stakeholders indicates this approach should be explored further.

Requirements evolve over the development lifecycle of a software project. Agile practices are designed specifically to address this challenge while showing early and continuous progress towards project goals. Applying an agile approach allows stakeholders to adapt the scope and capabilities of a development release to changing market needs. More recently, an agile approach has been recommended for developing the architecture of software systems, enabling the design to support current requirements and early releases while evolving to meet future expectations. Our experience defining emergent software systems to build a product line architecture for advanced data analytics demonstrates the benefits that can be gained from prioritizing work activities and delaying architecture decisions. This paper proposes a process and ontology for agile architecture development. Only the necessary aspects for each evolutionary release are designed and prototyped, as determined by expectations of the identified application domain scenarios. Feedback from implementing the scenarios using the architecture extends our understanding of the requirements and provides the backlog for successive design iterations.

Multi-core CPUs are now common in modern computers. To get access to effectively an unlimited supply of compute resources, software programs that have been highly optimized to use a single CPU need to be converted where possible to use concurrency. We have initiated our concurrency software research for performance enhancement on a large-scale system with high throughput and low latency transactions. In this paper, we report our experience, experiments, and results in various aspects of concurrency design and programming, including multi-threaded prototypes, static and dynamic concurrency analysis, future techniques and trends, concurrency experiments, and concurrency design patterns. Based on the concurrency experiments, we achieved at least 80 percent overall performance increases as measured by transaction throughput. As a result, capital expenditures for large scale deployments can be significantly reduced.