Optimization is omnipresent in our world. Its numerous applications spread from industrial cases, such as logistics, construction management or production planning; to the private sphere, filled with problems of selecting daycare or vacation planning. In this thesis, we concentrate on expensive black-box optimization (EBBO) problems, a subset of optimization problems (OPs), which are characterized by an expensive cost of evaluating an objective function. Such OPs are reoccurring in various domains, being known as: hyperpameter optimization in machine learning, performance configuration optimization or parameter tuning in search-based software engineering, simulation optimization in operations research, meta-optimization or parameter tuning in the optimization domain itself. High diversity of domains introduces a plethora of solving approaches, which adhere to a similar structure and workflow, but differ in details. The software frameworks stemming from different areas possess only partially intersecting manageability points, i.e., lack manageability. In this thesis, we argue that the lack of manageability in EBBO is a major problem, which leads to underachieving optimization quality. The goal of this thesis is to study the role of manageability in EBBO and to investigate whether improving the manageability of EBBO frameworks increases optimization quality. To reach this goal, we appeal to software product line engineering (SPLE), a methodology for developing highly-manageable software systems. Based on the foundations of SPLE, we introduce a novel framework for EBBO called BRISE. It offers: 1) a loosely-coupled software architecture, separating concerns of the experiment designer and the developer of EBBO strategies; 2) a full coverage of all EBBO problem types; and 3) a context-aware variability model, which captures the experiment-designer-defined OP with the content model; and manageability points including their variants and constraints with the cardinality-based feature model. High manageability of the introduced BRISE framework enables us: 1) to extend the framework with novel efficient strategies, such as adaptive repetition management; and 2) to introduce novel EBBO mechanisms, such as multi-objective compositional surrogate modeling, dynamic sampling and hierarchical surrogate modeling. The evaluation of the novel approaches with a set of case studies, including: the WFG benchmark for multi-objective optimization, combined selection and parameter control of meta-heuristics, and energy optimization; demonstrated their superiority over the state-of-the-art competitors. Thus, it supports the research hypothesis of this thesis: Improving manageability of an EBBO framework enables to increase optimization quality.

Modern business applications are getting increasingly distributed as multi-tenant software as a service (SaaS). This leads to new challenges in terms of quality assurance, because all customers are directly affected by software changes. The resulting problem is to proactively determinate evolutionary effects. Because SaaS applications are often realized in the sense of a software product line, this thesis examines ways of using feature models to face the mentioned problem. For this purpose, two approaches are analyzed: extended feature models with quality attributes annotated per feature and the analysis of structural aspects of feature models and corresponding concrete configurations. The presented attributed feature model approach measures the quality of concrete configurations to make configurations comparable according to specific quality goals. Criteria are elicited for when configurations can be compared to draw helpful conclusions. The structural approach focuses economic questions that are quality assurance related, such as identifying features that none of the tenants selected in their application configurations. Furthermore, three algorithms are presented that demonstrate the structural analysis approach to gather information relevant to quality assurance.

To offer customisable software, there are two main concepts yet: software product lines that allow the product customisation based on a fixed set of variability and software ecosystems, allowing an open product customisation based on a common platform. Offering a software family that enables external developers to supply software artefacts means to offer a common platform as part of an ecosystem and to sacrifice variability control. Keeping full variability control means to offer a customisable product as a product line, but without the support for external contributors. This thesis proposes a third concept of variable software: partly open software families. They combine a customisable platform similar to product lines with controlled openness similar to ecosystems. As a major contribution of this thesis a variability modelling concept is proposed which is part of a variability management for these partly open software families. This modelling concept is based on feature models and extends them to support open variability modelling by means of interfaces, structural interface specifications and the inclusion of semantic information. Additionally, the introduction of a rights management allows multiple contributors to work with the model. This is required to enable external developers to use the model for the concrete extension development. The feasibility of the proposed model is evaluated using a prototypically developed modelling tool and by means of a case study based on a car infotainment system.

Die Konzepte zur Erstellung von Software-Produktlinien dienen der ingenieurmäßigen, unternehmensinternen Wiederverwendung existierender Software-Artefakte. Existierende Ansätze nutzen von Hand erstellte und gewartete Kompositionsprogramme zum Assemblieren der Produkte entsprechend einer Variantenauswahl. Der Einsatz einer automatischen Planungskomponente sowie eines einfachen, erweiterbaren Komponenten-Meta-Modells hilft dabei, die dabei anfallenden Daten computergestützt zu verarbeiten. Die Integration beider Konzepte zu einem hybriden Ansatz ermöglicht die Neuerstellung von Produkten, die nicht von Anfang an als Produktlinie konzipiert sind, ohne eine spätere Umarbeitung unter Nutzung der automatischen Planungskomponente unnötig zu erschweren.

Software Product Lines (SPLs) are a successful approach to software reuse in the large. Even though tools exist to create SPLs, their evolution is widely unexplored. Evolving an SPL manually is tedious and error-prone as it is hard to avoid unintended side-effects that may harm the consistency of the SPL. In this thesis, the conceptual basis of a system for the evolution of model-based SPLs is presented, which maintains consistency of models and feature mapping. As basis, a novel classification is introduced that distinguishes evolutions by their potential to harm the mapping of an SPL. Furthermore, multiple remapping operators are presented that can remedy the negative side-effects of an evolution. A set of evolutions is complemented with appropriate remapping operations for the use in SPLs. Finally, an implementation of the evolution system in the SPL tool FeatureMapper is provided to demonstrate the capabilities of the presented approach when co-evolving models and feature mapping of an SPL.

Modern business applications are getting increasingly distributed as multi-tenant software as a service (SaaS). This leads to new challenges in terms of quality assurance, because all customers are directly affected by software changes. The resulting problem is to proactively determinate evolutionary effects. Because SaaS applications are often realized in the sense of a software product line, this thesis examines ways of using feature models to face the mentioned problem. For this purpose, two approaches are analyzed: extended feature models with quality attributes annotated per feature and the analysis of structural aspects of feature models and corresponding concrete configurations. The presented attributed feature model approach measures the quality of concrete configurations to make configurations comparable according to specific quality goals. Criteria are elicited for when configurations can be compared to draw helpful conclusions. The structural approach focuses economic questions that are quality assurance related, such as identifying features that none of the tenants selected in their application configurations. Furthermore, three algorithms are presented that demonstrate the structural analysis approach to gather information relevant to quality assurance.

To offer customisable software, there are two main concepts yet: software product lines that allow the product customisation based on a fixed set of variability and software ecosystems, allowing an open product customisation based on a common platform. Offering a software family that enables external developers to supply software artefacts means to offer a common platform as part of an ecosystem and to sacrifice variability control. Keeping full variability control means to offer a customisable product as a product line, but without the support for external contributors. This thesis proposes a third concept of variable software: partly open software families. They combine a customisable platform similar to product lines with controlled openness similar to ecosystems. As a major contribution of this thesis a variability modelling concept is proposed which is part of a variability management for these partly open software families. This modelling concept is based on feature models and extends them to support open variability modelling by means of interfaces, structural interface specifications and the inclusion of semantic information. Additionally, the introduction of a rights management allows multiple contributors to work with the model. This is required to enable external developers to use the model for the concrete extension development. The feasibility of the proposed model is evaluated using a prototypically developed modelling tool and by means of a case study based on a car infotainment system.

Die Konzepte zur Erstellung von Software-Produktlinien dienen der ingenieurmäßigen, unternehmensinternen Wiederverwendung existierender Software-Artefakte. Existierende Ansätze nutzen von Hand erstellte und gewartete Kompositionsprogramme zum Assemblieren der Produkte entsprechend einer Variantenauswahl. Der Einsatz einer automatischen Planungskomponente sowie eines einfachen, erweiterbaren Komponenten-Meta-Modells hilft dabei, die dabei anfallenden Daten computergestützt zu verarbeiten. Die Integration beider Konzepte zu einem hybriden Ansatz ermöglicht die Neuerstellung von Produkten, die nicht von Anfang an als Produktlinie konzipiert sind, ohne eine spätere Umarbeitung unter Nutzung der automatischen Planungskomponente unnötig zu erschweren.

Software Product Lines (SPLs) are a successful approach to software reuse in the large. Even though tools exist to create SPLs, their evolution is widely unexplored. Evolving an SPL manually is tedious and error-prone as it is hard to avoid unintended side-effects that may harm the consistency of the SPL. In this thesis, the conceptual basis of a system for the evolution of model-based SPLs is presented, which maintains consistency of models and feature mapping. As basis, a novel classification is introduced that distinguishes evolutions by their potential to harm the mapping of an SPL. Furthermore, multiple remapping operators are presented that can remedy the negative side-effects of an evolution. A set of evolutions is complemented with appropriate remapping operations for the use in SPLs. Finally, an implementation of the evolution system in the SPL tool FeatureMapper is provided to demonstrate the capabilities of the presented approach when co-evolving models and feature mapping of an SPL.:1 Introduction 1.1 Motivation for Evolving Software Product Lines 1.2 Outline of the Thesis 2 Background and Scope 2.1 Concepts and Terminology 2.1.1 Software Product Lines 2.1.2 Model-Driven Software Development 2.1.3 FeatureMapper 2.2 Scope 2.3 Related Work 3 Evolution of Software Product Lines 3.1 Evolutions 3.1.1 Evolutions in the Problem Space 3.1.2 Evolutions in the Solution Space 3.2 Classification Systems for Evolutions 3.2.1 Classification by Behavior Preservation 3.2.2 Classification Systems in the Literature 3.2.3 Classification by Semantical Extent of Model Changes 3.3 Remapping Operations 3.3.1 Remapping in the Problem Space 3.3.2 Remapping in the Solution Space 3.4 Classification and Remapping of Evolutions 3.4.1 Classification and Remapping of Problem Space Evolutions 3.4.2 Classification and Remapping of Solution Space Evolutions 4 A Framework for Evolutions in FeatureMapper 4.1 Relevant Technology 4.1.1 Refactory 4.1.2 EMFText 4.2 Implementation 4.2.1 Implementation of the Evolutions System 4.2.2 Implementation of the Remapping System 4.2.3 Implementation of the User Interface System 4.2.4 Implementation of the Test Suite 4.3 Possibilities for Extension 4.3.1 Adding New Evolutions 4.3.2 Adapting Existing Evolutions 5 Example Project 5.1 Initial Situation in 2001 5.2 First Revision in 2006 5.2.1 Removing the Cassette Player 5.2.2 Adding an MP3 CD Player 5.2.3 Adding a Personal Navigation Device 5.2.4 Changing the Implementation of the UI Builder 5.2.5 Summary of the Changes of the First Revision in 2006 5.3 Second Revision in 2011 5.3.1 Creating a Multi-Format CD Player 5.3.2 Enhancing Voice Recognition to Control the Audio Player 5.3.3 Restructuring Personal Navigation Maps 5.3.4 Changing the Implementation of the CD Player 5.3.5 Summary of the Changes of the Second Revision in 2011 5.4 Conclusion of the Example Project 6 Conclusion 6.1 Summarized Findings 6.2 Limitations and Drawbacks 6.3 Possibilities for Future Work 6.4 Theoretical and Practical Contributions A Object Remapping Specification (*.orspec) A.1 Object Remapping Specification Model A.2 Object Remapping Specification Syntax B DocBooklet (*.docbooklet) B.1 DocBooklet Model B.2 DocBooklet Syntax C NavMap (*.navmap) C.1 NavMap Model C.2 NavMap Syntax List of Figures List of Tables List of Listings Bibliography

Domain feature models concisely express commonality and variability among variants of a software product line. For separation of concerns, e.g., due to legal restrictions, technical considerations, and business requirements, multi-view approaches restrict the configuration choices on feature models for different stakeholders. However, recent approaches lack a formalization for precise, yet flexible specifications of views that ensure every derivable configuration perspective to obey feature model semantics. Here, we introduce a novel approach for clustering feature models to create multi-perspectives. Such customized perspectives result from composition of multiple concern-relevant views. A structured view model is used to organize feature groups, whereat a feature can be contained in multiple views. We provide formalizations for view composition and guaranteed consistency of the resulting perspectives w.r.t. feature model semantics. Thereupon, an efficient algorithm to verify consistency for entire clusterings is provided. We present an implementation and evaluate our concepts on two case studies.