Reusability of assets within a family of products is the major goal of Software Product Line Engineering (SPLE), therefore managing variability is an important task in SPLs. Configuration management in the context of software product line engineering is more complicated than that in single systems engineering due to &rdquo / variability in space&rdquo / in addition to &rdquo / variability in time&rdquo / of core assets. In this study, a method for documenting variability in executable configuration items, namely components, is proposed by associating them with the Orthogonal Variability Model (OVM) which introduces variability as a separate model. The main aim is to trace variability in dierent configurations by explicitly documenting variability information for components. The links between OVM elements and components facilitate tool support for product derivation as the components matching the selected variations can be gathered by following the links. The proposed scheme is demonstrated on a case study about a radar GUI variability model.

abstract: In the middle of the 20th century in the United States, transportation and infrastructure development became a priority on the national agenda, instigating the development of mathematical models that would predict transportation network performance. Approximately 40 years later, transportation planning models again became a national priority, this time instigating the development of highly disaggregate activity-based traffic models called microsimulations. These models predict the travel on a network at the level of the individual decision-maker, but do so with a large computational complexity and processing time requirement. The vast resources and steep learning curve required to integrate microsimulation models into the general transportation plan have deterred planning agencies from incorporating these tools. By researching the stochastic variability in the results of a microsimulation model with varying random number seeds, this paper evaluates the number of simulation trials necessary, and therefore the computational effort, for a planning agency to reach stable model outcomes. The microsimulation tool used to complete this research is the Transportation Analysis and Simulation System (TRANSIMS). The requirements for initiating a TRANSIMS simulation are described in the paper. Two analysis corridors are chosen in the Metropolitan Phoenix Area, and the roadway performance characteristics volume, vehicle-miles of travel, and vehicle-hours of travel are examined in each corridor under both congested and uncongested conditions. Both congested and uncongested simulations are completed in twenty trials, each with a unique random number seed. Performance measures are averaged for each trial, providing a distribution of average performance measures with which to test the stability of the system. The results of this research show that the variability in outcomes increases with increasing congestion. Although twenty trials are sufficient to achieve stable solutions for the uncongested state, convergence in the congested state is not achieved. These results indicate that a highly congested urban environment requires more than twenty simulation runs for each tested scenario before reaching a solution that can be assumed to be stable. The computational effort needed for this type of analysis is something that transportation planning agencies should take into consideration before beginning a traffic microsimulation program. / Dissertation/Thesis / M.S. Civil Engineering 2010

Die vorliegende Arbeit beschäftigt sich mit der Frage, wie Variabilitätsinformationen aus den Quelltext von Generatoren extrahiert werden können. Zu diesem Zweck wurde eine Klassifizierung von Variablen entwickelt, die im Vergleich zu bestehenden Ansätzen eine genauere Identifikation von Merkmalen ermöglicht. Zudem bildet die Unterteilung die Basis der Erkennung von Merkmalinteraktionen und Cross-tree-Constraints. Weiterhin wird gezeigt, wie die gewonnenen Informationen durch Merkmalmodelle dargestellt werden können. Da diese auf dem Generator-Quelltext basieren, liefern sie Erkenntnisse über den Lösungsraum der Domäne. Es wird sichtbar, aus welchen Implementierungskomponenten ein Merkmal besteht und welche Beziehungen es zwischen Merkmalen gibt. Allerdings liefert ein automatisch generiertes Merkmalmodell nur wenig Erkenntnisse über den Lösungsraum. Außerdem wurde ein Prototyp entwickelt, der eine Automatisierung des beschriebenen Extraktionsprozesses ermöglicht.

Configurable process models are integrated representations of multiple variants of a process model in a given domain, e.g. multiple variants of a shipment-to-delivery process in the logistics domain. Configurable process models provide a basis for managing variability and for enabling reuse of process models in Process-Aware Information Systems. Rather than designing process models from scratch, analysts can derive process models by configuring existing ones, thereby reusing proven practices. This thesis starts with the observation that existing approaches for capturing and managing configurable process models suffer from three shortcomings that affect their usability in practice. Firstly, configuration in existing approaches is performed manually and as such it is error-prone. In particular, analysts are left with the burden of ensuring the correctness of the individualized models. Secondly, existing approaches suffer from a lack of decision support for the selection of configuration alternatives. Consequently, stakeholders involved in the configuration of process models need to possess expertise both in the application domain and in the modeling language employed. This assumption represents an adoption obstacle in domains where users are unfamiliar with modeling notations. Finally, existing approaches for configurable process modeling are limited in scope to control-flow aspects, ignoring other equally important aspects of process models such as object flow and resource management. Following a design science research method, this thesis addresses the above shortcomings by proposing an integrated framework to manage the configuration of process models. The framework is grounded on three original and interrelated contributions: (i) a conceptual foundation for correctness-preserving configuration of process models; (ii) a questionnaire-driven approach for process model configuration, providing decision support and abstraction from modeling notations; (iii) a meta-model for configurable process models covering control-flow, data objects and resources. While the framework is language-independent, an embodiment of the framework in the context of a process modeling language used in practice is also developed in this thesis. The framework was formally defined and validated using four scenarios taken from different domains. Moreover, a comprehensive toolset was implemented to support the validation of the framework.