Dieter K. Hammer

Tool Support for Architectural Decisions

In contrast to software architecture models, architectural decisions are often not explicitly documented, and therefore eventually lost. This contributes to major problems such as high-cost system evolution, stakeholders mis-communication, and limited reusability of core system assets. An approach is outlined that systematically and semi-automatically documents architectural decisions and allows them to be effectively shared by the stakeholders. A first attempt is presented that partially implements the approach by binding architectural decisions, models and the system implementation. The approach is demonstrated with an example demonstrating its usefulness with regards to some industrial use cases.

DySOA: making service systems self-adaptive

Service-centric systems exist in a very dynamic environment. This requires these systems to adapt at runtime in order to keep fulfilling their QoS. In order to create self-adaptive service systems, developers should not only design the service architecture, but also need to design the self-adaptability aspects in a structured way. A key aspect in creating these self-adaptive service systems is modeling runtime variability properties. In this paper, we propose DySOA (Dynamic Service-Oriented Architecture), an architecture that extends service-centric applications to make them self-adaptive. DySOA allows developers to explicitly model elements that deal with QoS evaluation and variable composition configurations. Having the DySOA elements explicit enables separation of concerns, making them adaptable at runtime and reusable in next versions. We demonstrate the use of DySOA with an example.

Scenario-based decision making for architectural variability in product families

In this paper, we present a systematic approach towards decision making for variability in product families in the context of uncertainty. Our approach consists of the following ingredients: a suitable set of architectural views that bridge the gap between customer needs and available technology, a multi-view variation modeling technique, the selection of several scenarios of different kinds, and a quantitative analysis of quality aspects for these scenarios.

Creating self-adaptive service systems with Dysoa

Service-centric systems exist in a very dynamic environment, which requires these systems to adapt at runtime in order to keep fulfilling its QoS requirements to its users. In order to create self-adaptive service-centric systems, developers not only design the service architecture, but need to design the self-adaptability aspects in a structured way. Current service standards and technologies do not provide a general architecture in which all aspects for self-adaptability can be designed. In this paper we propose DySOA (dynamic service-oriented architecture), an architecture that extends service-centric applications to make them self-adaptive. DySOA allows developers to explicitly model the process and components that deal with determining the QoS of the running system, with evaluating the QoS, and with reconfiguring the system when necessary. Having the DySOA elements explicit enables separation of concerns, making the DySOA elements adaptable at runtime and reusable in next versions. We demonstrate how to use DySOA with an example.

A scenario-driven approach for value, risk, and cost analysis in system architecting for innovation

We present a quantitative method for scenario-driven value, risk, and cost analysis when proposing new system architectures for innovation projects. The method helps to articulate the relative benefits and/or disadvantages of the proposed set of scenarios in the early architecting phases of a new system. It provides the arguments on which to base an informed decision to select the final architectural scenarios for further consideration in the design. In this paper we present a case study in which we applied the proposed method.

A Method for Strategic Scenario-Based Architecting

Strategic decisions have to be made when long-lasting architectures for software-intensive systems are developed. It is a good idea to consider various changes in the business environment before the final system architecture is proposed. Since the future cannot be predicted accurately, strategic scenarios are a useful way of guiding the strategic decision-making process. Strategic scenarios can be defined as stories that describe plausible futures; they are particularly useful for guiding ones perception of the future. This paper presents our approach to the use of strategic scenarios for directing the strategic and tactical decision-making process when developing long-lasting system architectures. This approach was applied in a case study carried out in the medical imaging domain.